WorldWideScience

Sample records for fotoehlektricheskie moduli na

  1. Biļešu tirdzniecības risinājuma zāles plāna modulis

    OpenAIRE

    Bušs, Jēkabs

    2015-01-01

    Biļešu tirdzniecības risinājuma zāles plāna modulis, ir daļa no biļešu tirdzniecības programmprodukta. Modulis sniedz iespēju iestādes klientiem ērti aplūkot zāles plānojumu, kā arī iestādes darbiniekiem izmantot to kā zāles plānojuma administrēšanas un tirdzniecības galveno rīku. Modulis sniedz iespēju apskatīt konkrētos datus par attiecīgām izrādēm, sniedz iespēju apskatīt un uzstādīt attiecīgo izrāžu bloķētās vietas, bet pats galvenais, modulis sniedz iespēju iestādes darbiniekiem ar g...

  2. Heterotic moduli stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Cicoli, M. [Bologna Univ. (Italy). Dipt. Fisica ed Astronomia; INFN, Bologna (Italy); Adbus Salam ICTP, Trieste (Italy); De Alwis, S. [Adbus Salam ICTP, Trieste (Italy); Colorado Univ., Boulder, CO (United States). UCB 390 Physics Dept.; Westphal, A. [DESY Hamburg (Germany). Theory Group

    2013-04-15

    We perform a systematic analysis of moduli stabilization for weakly coupled heterotic string theory compactified on smooth Calabi-Yau three-folds. We focus on both supersymmetric and supersymmetry breaking vacua of generic (0,2) compactifications obtained by minimising the total (F+D)-term scalar potential. After reviewing how to stabilise all the geometric moduli in a supersymmetric way by including fractional fluxes, non-perturbative and threshold effects, we show that the inclusion of {alpha}' corrections leads to new de Sitter or nearly Minkowski vacua which break supersymmetry spontaneously. The minimum lies at moderately large volumes of all the geometric moduli, at perturbative values of the string coupling and at the right phenomenological value of the GUT gauge coupling. However the structure of the heterotic 3-form flux used for complex structure moduli stabilization does not contain enough freedom to tune the superpotential. This results in the generic prediction of high-scale supersymmetry breaking around the GUT scale. We finally provide a dynamical derivation of anisotropic compactifications with stabilized moduli which allow for perturbative gauge coupling unification around 10{sup 16} GeV.

  3. Moduli-induced baryogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Ishiwata, Koji; Jeong, Kwang Sik [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Takahashi, Fuminobu [Tohoku Univ., Sendai (Japan). Dept. of Physics; Tokyo Univ., Kashiwa (Japan). Kavli IPMU, TODIAS

    2013-12-15

    We study a scenario for baryogenesis in modular cosmology and discuss its implications for the moduli stabilization mechanism and the supersymmetry (SUSY) breaking scale. If moduli fields dominate the Universe and decay into the standard model particles through diatonic couplings, the right amount of baryon asymmetry can be generated through CP violating decay of gluino into quark and squark followed by baryon-number violating squark decay. We find that, in the KKLT-type moduli stabilization, at least two non-perturbative terms are required to obtain a sizable CP phase, and that the successful baryogenesis is possible for the soft SUSY breaking mass heavier than O(1) TeV. A part of the parameter space for successful baryogenesis can be probed at the collider experiments, dinucleon decay search experiment, and the measurements of electric dipole moments of neutron and electron. It is also shown that similar baryogenesis works in the case of the gravitino- or the saxion-dominated Universe.

  4. Oscillons from string moduli

    Science.gov (United States)

    Antusch, Stefan; Cefalà, Francesco; Krippendorf, Sven; Muia, Francesco; Orani, Stefano; Quevedo, Fernando

    2018-01-01

    A generic feature of string compactifications is the presence of many scalar fields, called moduli. Moduli are usually displaced from their post-inflationary minimum during inflation. Their relaxation to the minimum could lead to the production of oscillons: localised, long-lived, non-linear excitations of the scalar fields. Here we discuss under which conditions oscillons can be produced in string cosmology and illustrate their production and potential phenomenology with two explicit examples: the case of an initially displaced volume modulus in the KKLT scenario and the case of a displaced blow-up Kähler modulus in the Large Volume Scenario (LVS). One, in principle, observable consequence of oscillon dynamics is the production of gravitational waves which, contrary to those produced from preheating after high scale inflation, could have lower frequencies, closer to the currently observable range. We also show that, for the considered parameter ranges, oscillating fibre and volume moduli do not develop any significant non-perturbative dynamics. Furthermore, we find that the vacua in the LVS and the KKLT scenario are stable against local overshootings of the field into the decompatification region, which provides an additional check on the longevity of these metastable configurations.

  5. Moduli of weighted hyperplane arrangements

    CERN Document Server

    Lahoz, Martí; Macrí, Emanuele; Stellari, Paolo

    2015-01-01

    This book focuses on a large class of geometric objects in moduli theory and provides explicit computations to investigate their families. Concrete examples are developed that take advantage of the intricate interplay between Algebraic Geometry and Combinatorics. Compactifications of moduli spaces play a crucial role in Number Theory, String Theory, and Quantum Field Theory – to mention just a few. In particular, the notion of compactification of moduli spaces has been crucial for solving various open problems and long-standing conjectures. Further, the book reports on compactification techniques for moduli spaces in a large class where computations are possible, namely that of weighted stable hyperplane arrangements.

  6. Kahler Moduli Inflation Revisited

    CERN Document Server

    Blanco-Pillado, Jose J; Copeland, Edmund J; Gomez-Reino, Marta; Nunes, Nelson J

    2010-01-01

    We perform a detailed numerical analysis of inflationary solutions in Kahler moduli of type IIB flux compactifications. We show that there are inflationary solutions even when all the fields play an important role in the overall shape of the scalar potential. Moreover, there exists a direction of attraction for the inflationary trajectories that correspond to the constant volume direction. This basin of attraction enables the system to have an island of stability in the set of initial conditions. We provide explicit examples of these trajectories, compute the corresponding tilt of the density perturbations power spectrum and show that they provide a robust prediction of n_s approximately 0.96 for 60 e-folds of inflation.

  7. Moduli spaces in algebraic geometry

    International Nuclear Information System (INIS)

    Goettsche, L.

    2000-01-01

    This volume of the new series of lecture notes of the Abdus Salam International Centre for Theoretical Physics contains the lecture notes of the School on Algebraic Geometry which took place at the Abdus Salam International Centre for Theoretical Physics from 26 July to 13 August 1999. The school consisted of 2 weeks of lecture courses and one week of conference. The topic of the school was moduli spaces. More specifically the lectures were divided into three subtopics: principal bundles on Riemann surfaces, moduli spaces of vector bundles and sheaves on projective varieties, and moduli spaces of curves

  8. Moduli space of torsional manifolds

    International Nuclear Information System (INIS)

    Becker, Melanie; Tseng, L.-S.; Yau, S.-T.

    2007-01-01

    We characterize the geometric moduli of non-Kaehler manifolds with torsion. Heterotic supersymmetric flux compactifications require that the six-dimensional internal manifold be balanced, the gauge bundle be Hermitian Yang-Mills, and also the anomaly cancellation be satisfied. We perform the linearized variation of these constraints to derive the defining equations for the local moduli. We explicitly determine the metric deformations of the smooth flux solution corresponding to a torus bundle over K3

  9. Moduli mediation without moduli-induced gravitino problem

    Energy Technology Data Exchange (ETDEWEB)

    Akita, Kensuke [Department of Physics, Waseda University, Tokyo, 169-8555 (Japan); Kobayashi, Tatsuo [Department of Physics, Hokkaido University,Sapporo, 060-0810 (Japan); Oikawa, Akane; Otsuka, Hajime [Department of Physics, Waseda University, Tokyo, 169-8555 (Japan)

    2016-05-30

    We study the moduli-induced gravitino problem within the framework of the phenomenologically attractive mirage mediations. The huge amount of gravitino generated by the moduli decay can be successfully diluted by introducing an extra light modulus field which does not induce the supersymmetry breaking. Since the lifetime of extra modulus field becomes longer than usually considered modulus field, our proposed mechanism is applied to both the low- and high-scale supersymmetry breaking scenarios. We also point out that such an extra modulus field appears in the flux compactification of type II string theory.

  10. String moduli inflation. An overview

    International Nuclear Information System (INIS)

    Cicoli, Michele; Quevedo, Fernando

    2011-06-01

    We present an overview of inflationary models derived from string theory focusing mostly on closed string moduli as inflatons. After a detailed discussion of the η-problem and different approaches to address it, we describe possible ways to obtain a de Sitter vacuum with all closed string moduli stabilised. We then look for inflationary directions and present some of the most promising scenarios where the inflatons are either the real or the imaginary part of Kaehler moduli. We pay particular attention on extracting potential observable implications, showing how most of the scenarios predict negligible gravitational waves and could therefore be ruled out by the Planck satellite. We conclude by briefly mentioning some open challenges in string cosmology beyond deriving just inflation. (orig.)

  11. On the Moduli of Convexity

    Czech Academy of Sciences Publication Activity Database

    Guirao, A. J.; Hájek, Petr Pavel

    2007-01-01

    Roč. 135, č. 10 (2007), s. 3233-3240 ISSN 0002-9939 R&D Projects: GA AV ČR IAA100190502 Institutional research plan: CEZ:AV0Z10190503 Keywords : Banach spaces * moduli of convexity * uniformly rotund norms Subject RIV: BA - General Mathematics Impact factor: 0.520, year: 2007

  12. Moduli fields as quintessence and the chameleon

    International Nuclear Information System (INIS)

    Brax, Philippe; Martin, Jerome

    2007-01-01

    We consider models where moduli fields are not stabilized and play the role of quintessence. In order to evade gravitational tests, we investigate the possibility that moduli behave as chameleon fields. We find that, for realistic moduli superpotentials, the chameleon effect is not strong enough, implying that moduli quintessence models are gravitationally ruled out. More generally, we state a no-go theorem for quintessence in supergravity whereby models either behave like a pure cosmological constant or violate gravitational tests

  13. Moduli backreaction on inflationary attractors

    International Nuclear Information System (INIS)

    Roest, Diederik; Werkman, Pelle

    2016-07-01

    We investigate the interplay between moduli dynamics and inflation, focusing on the KKLT- scenario and cosmological α-attractors. General couplings between these sectors can induce a significant backreaction and potentially destroy the inflationary regime; however, we demonstrate that this generically does not happen for α-attractors. Depending on the details of the superpotential, the volume modulus can either be stable during the entire inflationary trajectory, or become tachyonic at some point and act as a waterfall field, resulting in a sudden end of inflation. In the latter case there is a universal supersymmetric minimum where the scalars end up, preventing the decompactification scenario. The gravitino mass is independent from the inflationary scale with no fine-tuning of the parameters. The observational predictions conform to the universal value of attractors, fully compatible with the Planck data, with possibly a capped number of e-folds due to the interplay with moduli.

  14. Moduli spaces of riemannian metrics

    CERN Document Server

    Tuschmann, Wilderich

    2015-01-01

    This book studies certain spaces of Riemannian metrics on both compact and non-compact manifolds. These spaces are defined by various sign-based curvature conditions, with special attention paid to positive scalar curvature and non-negative sectional curvature, though we also consider positive Ricci and non-positive sectional curvature. If we form the quotient of such a space of metrics under the action of the diffeomorphism group (or possibly a subgroup) we obtain a moduli space. Understanding the topology of both the original space of metrics and the corresponding moduli space form the central theme of this book. For example, what can be said about the connectedness or the various homotopy groups of such spaces? We explore the major results in the area, but provide sufficient background so that a non-expert with a grounding in Riemannian geometry can access this growing area of research.

  15. Moduli Backreaction on Inflationary Attractors

    CERN Document Server

    Roest, Diederik; Werkman, Pelle

    2016-01-01

    We investigate the interplay between moduli dynamics and inflation, focusing on the KKLT-scenario and cosmological $\\alpha$-attractors. General couplings between these sectors can induce a significant backreaction and potentially destroy the inflationary regime; however, we demonstrate that this generically does not happen for $\\alpha$-attractors. Depending on the details of the superpotential, the volume modulus can either be stable during the entire inflationary trajectory, or become tachyonic at some point and act as a waterfall field, resulting in a sudden end of inflation. In the latter case there is a universal supersymmetric minimum where the scalars end up, preventing the decompactification scenario. The observational predictions conform to the universal value of attractors, fully compatible with the Planck data, with possibly a capped number of e-folds due to the interplay with moduli.

  16. Moduli destabilization via gravitational collapse

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Dong-il [Sogang Univ., Seoul (Korea, Republic of). Center for Quantum Spacetime; Pedro, Francisco G. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany). Theory Group; Yeom, Dong-han [Sogang Univ., Seoul (Korea, Republic of). Center for Quantum Spacetime; Kyoto Univ. (Japan). Yukawa Inst. for Theoretical Physics

    2013-06-15

    We examine the interplay between gravitational collapse and moduli stability in the context of black hole formation. We perform numerical simulations of the collapse using the double null formalism and show that the very dense regions one expects to find in the process of black hole formation are able to destabilize the volume modulus. We establish that the effects of the destabilization will be visible to an observer at infinity, opening up a window to a region in spacetime where standard model's couplings and masses can differ significantly from their background values.

  17. A Metric for Heterotic Moduli

    Science.gov (United States)

    Candelas, Philip; de la Ossa, Xenia; McOrist, Jock

    2017-12-01

    Heterotic vacua of string theory are realised, at large radius, by a compact threefold with vanishing first Chern class together with a choice of stable holomorphic vector bundle. These form a wide class of potentially realistic four-dimensional vacua of string theory. Despite all their phenomenological promise, there is little understanding of the metric on the moduli space of these. What is sought is the analogue of special geometry for these vacua. The metric on the moduli space is important in phenomenology as it normalises D-terms and Yukawa couplings. It is also of interest in mathematics, since it generalises the metric, first found by Kobayashi, on the space of gauge field connections, to a more general context. Here we construct this metric, correct to first order in {α^{\\backprime}}, in two ways: first by postulating a metric that is invariant under background gauge transformations of the gauge field, and also by dimensionally reducing heterotic supergravity. These methods agree and the resulting metric is Kähler, as is required by supersymmetry. Checking the metric is Kähler is intricate and the anomaly cancellation equation for the H field plays an essential role. The Kähler potential nevertheless takes a remarkably simple form: it is the Kähler potential of special geometry with the Kähler form replaced by the {α^{\\backprime}}-corrected hermitian form.

  18. SUGRA chaotic inflation and moduli stabilisation

    International Nuclear Information System (INIS)

    Davis, S.C.

    2008-01-01

    Chaotic inflation predicts a large gravitational wave signal which can be tested by the upcoming Planck satellite. We discuss a SUGRA implementation of chaotic inflation in the presence of moduli fields, and find that inflation does not work with a generic KKLT moduli stabilisation potential. A viable model can be constructed with a fine-tuned moduli sector, but only for a very specific choice of Kaeahler potential. Our analysis also shows that inflation models satisfying ∂ i W inf =0 for all inflation sector fields φ i can be combined successfully with a fine-tuned moduli sector. (orig.)

  19. Moduli stabilization in non-geometric backgrounds

    International Nuclear Information System (INIS)

    Becker, Katrin; Becker, Melanie; Vafa, Cumrun; Walcher, Johannes

    2007-01-01

    Type II orientifolds based on Landau-Ginzburg models are used to describe moduli stabilization for flux compactifications of type II theories from the world-sheet CFT point of view. We show that for certain types of type IIB orientifolds which have no Kaehler moduli and are therefore intrinsically non-geometric, all moduli can be explicitly stabilized in terms of fluxes. The resulting four-dimensional theories can describe Minkowski as well as anti-de Sitter vacua. This construction provides the first string vacuum with all moduli frozen and leading to a 4D Minkowski background

  20. The moduli and gravitino (non)-problems in models with strongly stabilized moduli

    International Nuclear Information System (INIS)

    Evans, Jason L.; Olive, Keith A.; Garcia, Marcos A.G.

    2014-01-01

    In gravity mediated models and in particular in models with strongly stabilized moduli, there is a natural hierarchy between gaugino masses, the gravitino mass and moduli masses: m 1/2 << m 3/2 << m φ . Given this hierarchy, we show that 1) moduli problems associated with excess entropy production from moduli decay and 2) problems associated with moduli/gravitino decays to neutralinos are non-existent. Placed in an inflationary context, we show that the amplitude of moduli oscillations are severely limited by strong stabilization. Moduli oscillations may then never come to dominate the energy density of the Universe. As a consequence, moduli decay to gravitinos and their subsequent decay to neutralinos need not overpopulate the cold dark matter density

  1. Gravitational Particle Production and the Moduli Problem

    CERN Document Server

    Felder, G; Linde, Andrei D; Felder, Gary; Kofman, Lev; Linde, Andrei

    2000-01-01

    A theory of gravitational production of light scalar particles during and after inflation is investigated. We show that in the most interesting cases where long-wavelength fluctuations of light scalar fields can be generated during inflation, these fluctuations rather than quantum fluctuations produced after inflation give the dominant contribution to particle production. In such cases a simple analytical theory of particle production can be developed. Application of our results to the theory of quantum creation of moduli fields demonstrates that if the moduli mass is smaller than the Hubble constant then these fields are copiously produced during inflation. This gives rise to the cosmological moduli problem even if there is no homogeneous component of the classical moduli field in the universe. To avoid this version of the moduli problem it is necessary for the Hubble constant H during the last stages of inflation and/or the reheating temperature T_R after inflation to be extremely small.

  2. K3 surfaces and their moduli

    CERN Document Server

    Farkas, Gavril; Geer, Gerard

    2016-01-01

    This book provides an overview of the latest developments concerning the moduli of K3 surfaces. It is aimed at algebraic geometers, but is also of interest to number theorists and theoretical physicists, and continues the tradition of related volumes like “The Moduli Space of Curves” and “Moduli of Abelian Varieties,” which originated from conferences on the islands Texel and Schiermonnikoog and which have become classics. K3 surfaces and their moduli form a central topic in algebraic geometry and arithmetic geometry, and have recently attracted a lot of attention from both mathematicians and theoretical physicists. Advances in this field often result from mixing sophisticated techniques from algebraic geometry, lattice theory, number theory, and dynamical systems. The topic has received significant impetus due to recent breakthroughs on the Tate conjecture, the study of stability conditions and derived categories, and links with mirror symmetry and string theory. At the same time, the theory of irred...

  3. Universal moduli spaces of Riemann surfaces

    Science.gov (United States)

    Ji, Lizhen; Jost, Jürgen

    2017-04-01

    We construct a moduli space for Riemann surfaces that is universal in the sense that it represents compact Riemann surfaces of any finite genus. This moduli space is a connected complex subspace of an infinite dimensional complex space, and is stratified according to genus such that each stratum has a compact closure, and it carries a metric and a measure that induce a Riemannian metric and a finite volume measure on each stratum. Applications to the Plateau-Douglas problem for minimal surfaces of varying genus and to the partition function of Bosonic string theory are outlined. The construction starts with a universal moduli space of Abelian varieties. This space carries a structure of an infinite dimensional locally symmetric space which is of interest in its own right. The key to our construction of the universal moduli space then is the Torelli map that assigns to every Riemann surface its Jacobian and its extension to the Satake-Baily-Borel compactifications.

  4. Geometry and quantization of moduli spaces

    CERN Document Server

    Andersen, Jørgen; Riera, Ignasi

    2016-01-01

    This volume is based on four advanced courses held at the Centre de Recerca Matemàtica (CRM), Barcelona. It presents both background information and recent developments on selected topics that are experiencing extraordinary growth within the broad research area of geometry and quantization of moduli spaces. The lectures focus on the geometry of moduli spaces which are mostly associated to compact Riemann surfaces, and are presented from both classical and quantum perspectives.

  5. Moduli stabilization in type IIB orientifolds

    International Nuclear Information System (INIS)

    Schulgin, W.

    2007-01-01

    This thesis deals with the stabilization of the moduli fields in the compactifications of the type IIB string theory on orientifolds. A concrete procedure for the construction of solutions, in which all moduli fields are fixed, yields the KKLT scenario. We study, on which models the scenario can be applied, if approximations of the original KKLT work are abandoned. We find that in a series of models, namely such without complex-structure moduli the construction of the consistent solutions in the framework of the KKLT scenario is not possible. The nonperturbative effects, like D3 instantons and gaugino condensates are a further component of the KKLT scenario. They lead to the stabilization of the Kaehler moduli. We present criteria for the generation of the superpotential due to the D3 instantons at a Calaby-Yau manifold in presence of fluxes. Furthermore we show that although the presence of the nonperturbative superpotential in the equations of motions is correlated with the switching on of all ISD and IASD fluxes, the deciding criterium for the generation of the nonperturbative superpotential depends only on the fluxes of the type (2,1). Thereafter we discuss two models, in which we stabilize all moduli fields. Thereby it deals with Calabi-Yau orientifolds which have been obtained by a blow-up procedure from the Z 6-II and Z 2 x Z 4 orientifolds

  6. M-theory moduli space and cosmology

    International Nuclear Information System (INIS)

    Brustein, R.; Alwis, S.P. de; Novak, E.G.

    2003-01-01

    We conduct a systematic search for a viable string or M-theory cosmology, focusing on cosmologies that include an era of slow-roll inflation, after which the moduli are stabilized and the Universe is in a state with an acceptably small cosmological constant. We observe that the duality relations between different cosmological backgrounds of string or M-theory moduli space are greatly simplified, and that this simplification leads to a truncated moduli space within which possible cosmological solutions lie. We review some known challenges to four dimensional models in the ''outer,'' perturbative, region of moduli space, and use duality relations to extend them to models of all of the (compactified) perturbative string theories and 11D supergravity, including brane world models. We conclude that cosmologies restricted to the outer region are not viable, and that the most likely region of moduli space in which to find realistic cosmology is the 'central', nonperturbative region, with coupling and compact volume both of order unity, in string units

  7. Dynamical gauge coupling unification from moduli stabilization

    International Nuclear Information System (INIS)

    Choi, Kiwoon

    2006-01-01

    In D-brane models, different part of the 4-dimensional gauge group might originate from D-branes wrapping different cycles in the internal space, and then the standard model gauge couplings at the compactification scale are determined by different cycle-volume moduli. We point out that those cycle-volume moduli can naturally have universal vacuum expectation values up to small deviations suppressed by 1/8π 2 if they are stabilized by KKLT-type non-perturbative superpotential with properly chosen discrete parameters. This dynamical unification of gauge couplings is independent of the detailed form of the moduli Kahler potential, but relies crucially on the existence of low energy supersymmetry. If supersymmetry is broken by an uplifting brane as in KKLT compactification, again independently of the detailed form of the moduli Kahler potential, the moduli-mediated gaugino masses at the compactification scale are universal also, and are comparable to the anomaly-mediated gaugino masses. As a result, both the gauge coupling unification at high energy scale and the mirage mediation pattern of soft supersymmetry breaking masses are achieved naturally even when the different sets of the standard model gauge bosons originate from D-branes wrapping different cycles in the internal space

  8. A minicourse on moduli of curves

    International Nuclear Information System (INIS)

    Looijenga, E.

    2000-01-01

    These are notes that accompany a short course given at the School on Algebraic Geometry 1999 at the ICTP, Trieste. A major goal is to outline various approaches to moduli spaces of curves. In the last part I discuss the algebraic classes that naturally live on these spaces; these can be thought of as the characteristic classes for bundles of curves. (author)

  9. Roaming moduli space using dynamical triangulations

    NARCIS (Netherlands)

    Ambjørn, J.; Barkley, J.; Budd, T.G.

    2012-01-01

    In critical as well as in non-critical string theory the partition function reduces to an integral over modulispace after integration over matter fields. For non-critical string theory this moduli integrand is known for genus one surfaces. The formalism of dynamicaltriangulations provides us with a

  10. Moduli spaces of convex projective structures on surfaces

    DEFF Research Database (Denmark)

    Fock, V. V.; Goncharov, A. B.

    2007-01-01

    We introduce explicit parametrisations of the moduli space of convex projective structures on surfaces, and show that the latter moduli space is identified with the higher Teichmüller space for defined in [V.V. Fock, A.B. Goncharov, Moduli spaces of local systems and higher Teichmüller theory, ma.......AG/0311149]. We investigate the cluster structure of this moduli space, and define its quantum version....

  11. Dimensional reduction for D3-brane moduli

    Energy Technology Data Exchange (ETDEWEB)

    Cownden, Brad [Department of Physics & Astronomy, University of Manitoba,Winnipeg, Manitoba R3T 2N2 (Canada); Frey, Andrew R. [Department of Physics & Astronomy, University of Manitoba,Winnipeg, Manitoba R3T 2N2 (Canada); Department of Physics, University of Winnipeg,Winnipeg, Manitoba R3B 2E9 (Canada); Marsh, M.C. David [Department of Applied Mathematics and Theoretical Physics, University of Cambridge,Cambridge, CB3 0WA (United Kingdom); Underwood, Bret [Department of Physics, Pacific Lutheran University,Tacoma, WA 98447 (United States)

    2016-12-28

    Warped string compactifications are central to many attempts to stabilize moduli and connect string theory with cosmology and particle phenomenology. We present a first-principles derivation of the low-energy 4D effective theory from dimensional reduction of a D3-brane in a warped Calabi-Yau compactification of type IIB string theory with imaginary self-dual 3-form flux, including effects of D3-brane motion beyond the probe approximation, and find the metric on the moduli space of brane positions, the universal volume modulus, and axions descending from the 4-form potential. As D3-branes may be considered as carrying either electric or magnetic charges for the self-dual 5-form field strength, we present calculations in both duality frames. Our results are consistent with, but extend significantly, earlier results on the low-energy effective theory arising from D3-branes in string compactifications.

  12. Hybrid inflation and the moduli problem

    International Nuclear Information System (INIS)

    Berkooz, M.; Volansky, T.; Dine, M.

    2005-01-01

    We revisit some questions in supersymmetric hybrid inflation. We analyze the amount of fine-tuning required in various models, the problem of decay at the end of inflation and the generation of baryons after inflation. We find that the most natural setting for hybrid inflation is in supersymmetric models with nonrenormalizable couplings. Furthermore, we argue that almost inevitably, one of the fields involved is a modulus, with Planck scale variation. The resulting moduli problem can be solved in two ways: either by a massive modulus (which requires some fine-tuning), or an enhanced symmetry point, in which the moduli becomes strongly coupled to the standard model. Various possibilities for baryon production are discussed

  13. Dimensional reduction for D3-brane moduli

    Science.gov (United States)

    Cownden, Brad; Frey, Andrew R.; Marsh, M. C. David; Underwood, Bret

    2016-12-01

    Warped string compactifications are central to many attempts to stabilize moduli and connect string theory with cosmology and particle phenomenology. We present a first-principles derivation of the low-energy 4D effective theory from dimensional reduction of a D3-brane in a warped Calabi-Yau compactification of type IIB string theory with imaginary self-dual 3-form flux, including effects of D3-brane motion beyond the probe approximation, and find the metric on the moduli space of brane positions, the universal volume modulus, and axions descending from the 4-form potential. As D3-branes may be considered as carrying either electric or magnetic charges for the self-dual 5-form field strength, we present calculations in both duality frames. Our results are consistent with, but extend significantly, earlier results on the low-energy effective theory arising from D3-branes in string compactifications.

  14. Plutonium Elastic Moduli, Electron Localization, and Temperature

    International Nuclear Information System (INIS)

    Migliori, Albert; Mihut-Stroe, Izabella; Betts, Jon B.

    2008-01-01

    In almost all materials, compression is accompanied naturally by stiffening. Even in materials with zero or negative thermal expansion, where warming is accompanied by volume contraction it is the volume change that primarily controls elastic stiffness. Not so in the metal plutonium. In plutonium, alloying with gallium can change the sign of thermal expansion, but for the positive thermal- expansion monoclinic phase as well as the face-centered-cubic phase with either sign of thermal expansion, and the orthorhombic phase, recent measurements of elastic moduli show soften on warming by an order of magnitude more than expected, the shear and compressional moduli track, and volume seems irrelevant. These effects point toward a novel mechanism for electron localization, and have important implication for the pressure dependence of the bulk compressibility. (authors)

  15. Local string models and moduli stabilisation

    Science.gov (United States)

    Quevedo, Fernando

    2015-03-01

    A brief overview is presented of the progress made during the past few years on the general structure of local models of particle physics from string theory including: moduli stabilisation, supersymmetry breaking, global embedding in compact Calabi-Yau compactifications and potential cosmological implications. Type IIB D-brane constructions and the Large Volume Scenario (LVS) are discussed in some detail emphasising the recent achievements and the main open questions.

  16. BCFT moduli space in level truncation

    Czech Academy of Sciences Publication Activity Database

    Kudrna, Matěj; Maccaferri, C.

    2016-01-01

    Roč. 2016, č. 4 (2016), 1-33, č. článku 057. ISSN 1029-8479 R&D Projects: GA ČR(CZ) GA14-31689S Institutional support: RVO:68378271 Keywords : deformation: marginal * field theory: string * tachyon: potential * string: open * moduli space * effective potential * nonperturbative * toy model Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 6.063, year: 2016

  17. Supersymmetric moduli stabilization and high-scale inflation

    Directory of Open Access Journals (Sweden)

    Wilfried Buchmuller

    2014-09-01

    Full Text Available We study the back-reaction of moduli fields on the inflaton potential in generic models of F-term inflation. We derive the moduli corrections as a power series in the ratio of Hubble scale and modulus mass. The general result is illustrated with two examples, hybrid inflation and chaotic inflation. We find that in both cases the decoupling of moduli dynamics and inflation requires moduli masses close to the scale of grand unification. For smaller moduli masses the CMB observables are strongly affected.

  18. Arithmetic fundamental groups and moduli of curves

    International Nuclear Information System (INIS)

    Makoto Matsumoto

    2000-01-01

    This is a short note on the algebraic (or sometimes called arithmetic) fundamental groups of an algebraic variety, which connects classical fundamental groups with Galois groups of fields. A large part of this note describes the algebraic fundamental groups in a concrete manner. This note gives only a sketch of the fundamental groups of the algebraic stack of moduli of curves. Some application to a purely topological statement, i.e., an obstruction to the subjectivity of Johnson homomorphisms in the mapping class groups, which comes from Galois group of Q, is explained. (author)

  19. On moduli spaces in AdS{sub 4} supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Alwis, Senarath de [Colorado Univ., Boulder, CO (United States). Dept. of Physics; Louis, Jan [Hamburg Univ. (Germany). Fachbereich 12 - Physik; Hamburg Univ. (Germany). Zentrum fuer Mathematische Physik; McAllister, Liam [Cornell Univ., Ithaca, NY (United States). Dept. of Physics; Triendl, Hagen [CERN, Geneva (Switzerland). Theory Division, Physics Dept.; Westphal, Alexander [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Gruppe Theorie

    2013-12-15

    We study the structure of the supersymmetric moduli spaces of N=1 and N=2 supergravity theories in AdS{sub 4} backgrounds. In the N=1 case, the moduli space cannot be a complex submanifold of the Kaehler field space, but is instead real with respect to the inherited complex structure. In N=2 supergravity the same result holds for the vector multiplet moduli space, while the hypermultiplet moduli space is a Kaehler submanifold of the quaternionic-Kaehler field space. These findings are in agreement with AdS/CFT considerations.

  20. Singular points in moduli spaces of Yang-Mills fields

    International Nuclear Information System (INIS)

    Ticciati, R.

    1984-01-01

    This thesis investigates the metric dependence of the moduli spaces of Yang-Mills fields of an SU(2) principal bundle P with chern number -1 over a four-dimensional, simply-connected, oriented, compact smooth manifold M with positive definite intersection form. The purpose of this investigation is to suggest that the surgery class of the moduli space of irreducible connections is, for a generic metric, a Z 2 topological invariant of the smooth structure on M. There are three main parts. The first two parts are local analysis of singular points in the moduli spaces. The last part is global. The first part shows that the set of metrics for which the moduli space of irreducible connections has only non-degenerate singularities has codimension at least one in the space of all metrics. The second part shows that, for a one-parameter family of moduli spaces in a direction transverse to the set of metrics for which the moduli spaces have singularities, passing through a non-degenerate singularity of the simplest type changes the moduli space by a cobordism. The third part shows that generic one-parameter families of metrics give rise to six-dimensional manifolds, the corresponding family of moduli spaces of irreducible connections. It is shown that when M is homeomorphic to S 4 the six-dimensional manifold is a proper cobordism, thus establishing the independence of the surgery class of the moduli space on the metric on M

  1. Moduli stabilization and the pattern of sparticle spectra

    International Nuclear Information System (INIS)

    Choi, Kiwoon

    2008-01-01

    We discuss the pattern of low energy sparticle spectra which appears in some class of moduli stabilization scenario. In case that light moduli are stabilized by non-perturbative effects encoded in the superpotential and a phenomenologically viable de Sitter vacuum is obtained by a sequestered supersymmetry breaking sector, the anomaly-mediated soft terms become comparable to the moduli-mediated ones, leading to a quite distinctive pattern of low energy spacticle masses dubbed the mirage mediation pattern. We also discuss low energy sparticle masses in more general mixed-mediation scenario which includes a comparable size of gauge mediation in addition to the moduli and anomaly mediations.

  2. Monoids of moduli spaces of manifolds

    DEFF Research Database (Denmark)

    Galatius, Søren; Randal-Williams, Oscar

    2010-01-01

    with generalised orientations specified by a map ¿: X ¿ BO(d). The main result of [Acta Math. 202 (2009) 195–239] is a determination of the homotopy type of the classifying space BC¿. The goal of the present paper is a systematic investigation of subcategories D¿C¿ with the property that BD¿ BC¿, the smaller...... such D the better. We prove that in most cases of interest, D can be chosen to be a homotopy commutative monoid. As a consequence we prove that the stable cohomology of many moduli spaces of surfaces with ¿–structure is the cohomology of the  infinite loop space of a certain Thom spectrum MT...

  3. Compactifications of reductive groups as moduli stacks of bundles

    DEFF Research Database (Denmark)

    Martens, Johan; Thaddeus, Michael

    Let G be a reductive group. We introduce the moduli problem of "bundle chains" parametrizing framed principal G-bundles on chains of lines. Any fan supported in a Weyl chamber determines a stability condition on bundle chains. Its moduli stack provides an equivariant toroidal compactification of G...

  4. Canonical measures on the moduli spaces of compact Riemann surfaces

    International Nuclear Information System (INIS)

    Nag, S.

    1988-08-01

    We first study some explicit relations between the canonical line bundle and the Hodge bundle over moduli spaces for low genus. This leads to a natural measure on the moduli space of every genus which is related to the Siegel symplectic metric on Siegel upper half-space as well as to the Hodge metric on the Hodge bundle. (author). 9 refs

  5. The universal connection and metrics on moduli spaces

    International Nuclear Information System (INIS)

    Massamba, Fortune; Thompson, George

    2003-11-01

    We introduce a class of metrics on gauge theoretic moduli spaces. These metrics are made out of the universal matrix that appears in the universal connection construction of M. S. Narasimhan and S. Ramanan. As an example we construct metrics on the c 2 = 1 SU(2) moduli space of instantons on R 4 for various universal matrices. (author)

  6. Beauty is Attractive: Moduli Trapping at Enhanced Symmetry Points

    Energy Technology Data Exchange (ETDEWEB)

    Kofman, L

    2004-02-27

    We study quantum effects on moduli dynamics arising from the production of particles which are light at points of enhanced symmetry in moduli space. The resulting forces trap the moduli at these points. Moduli trapping occurs in time-dependent quantum field theory, as well as in systems of moving D-branes, where it leads the branes to combine into stacks. Trapping also occurs in the presence of gravity, though the range over which the moduli can roll is limited by Hubble friction. We observe that a scalar field trapped on a steep potential can induce a stage of acceleration of the universe, which we call trapped inflation. Moduli trapping ameliorates the cosmological moduli problem and may affect vacuum selection. In particular, rolling moduli are most powerfully attracted to the points of greatest symmetry. Given suitable assumptions about the dynamics of the very early universe, this effect might help to explain why among the plethora of possible vacuum states of string theory, we appear to live in one with a large number of (spontaneously broken) symmetries.

  7. Moduli of Riemann surfaces, transcendental aspects

    International Nuclear Information System (INIS)

    Hain, R.

    2000-01-01

    These notes are an informal introduction to moduli spaces of compact Riemann surfaces via complex analysis, topology and Hodge Theory. The prerequisites for the first lecture are just basic complex variables, basic Riemann surface theory up to at least the Riemann-Roch formula, and some algebraic topology, especially covering space theory. The first lecture covers moduli in genus 0 and genus 1 as these can be understood using relatively elementary methods, but illustrate many of the points which arise in higher genus. The notes cover more material than was covered in the lectures, and sometimes the order of topics in the notes differs from that in the lectures. We have seen in genus 1 case that M 1 is the quotient Γ 1 /X 1 of a contractible complex manifold X 1 = H by a discrete group Γ 1 = SL 2 (Z). The action of Γ 1 on X 1 is said to be virtually free - that is, Γ 1 has a finite index subgroup which acts (fixed point) freely on X 1 . In this section we will generalize this to all g >= 1 - we will sketch a proof that there is a contractible complex manifold Xg, called Teichmueller space, and a group Γ g , called the mapping class group, which acts virtually freely on X g . The moduli space of genus g compact Riemann surfaces is the quotient: M g = Γ g /X g . This will imply that M g has the structure of a complex analytic variety with finite quotient singularities. Teichmueller theory is a difficult and technical subject. Because of this, it is only possible to give an overview. In this lecture, we compute the orbifold Picard group of M g for all g >= 1. Recall that an orbifold line bundle over M g is a holomorphic line bundle L over Teichmueller space X g together with an action of the mapping class group Γ g on it such that the projection L → X g is Γ g -equivariant. An orbifold section of this line bundle is a holomorphic Γ g -equivariant section X g → L of L. This is easily seen to be equivalent to fixing a level l>= 3 and considering holomorphic

  8. Stretch Moduli of Ribonucleotide Embedded Short DNAs

    Science.gov (United States)

    Chiu, Hsiang-Chih; Koh, Kyung Duk; Riedo, Elisa; Storici, Francesca

    2013-03-01

    Understanding the mechanical properties of DNA is essential to comprehending the dynamics of many cellular functions. DNA deformations are involved in many mechanisms when genetic information needs to be stored and used. In addition, recent studies have found that Ribonucleotides (rNMPs) are among the most common non-standard nucleotides present in DNA. The presences of rNMPs in DNA might cause mutation, fragility or genotoxicity of chromosome but how they influence the structure and mechanical properties of DNA remains unclear. By means of Atomic Force Microscopy (AFM) based single molecule spectroscopy, we measure the stretch moduli of double stranded DNAs (dsDNA) with 30 base pairs and 5 equally embedded rNMPs. The dsDNAs are anchored on gold substrate via thiol chemistry, while the AFM tip is used to pick up and stretch the dsDNA from its free end through biotin-streptavidin bonding. Our preliminary results indicate that the inclusion of rNMPs in dsDNA might significantly change its stretch modulus, which might be important in some biological processes.

  9. Higher-Derivative Supergravity and Moduli Stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Ciupke, David; Westphal, Alexander [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group; Louis, Jan [Hamburg Univ. (Germany). Fachberich Physik; Hamburg Univ. (Germany). Zentrum fuer Mathematische Physik

    2015-05-15

    We review the ghost-free four-derivative terms for chiral superfields in N=1 supersymmetry and supergravity. These terms induce cubic polynomial equations of motion for the chiral auxiliary fields and correct the scalar potential. We discuss the different solutions and argue that only one of them is consistent with the principles of effective field theory. Special attention is paid to the corrections along flat directions which can be stabilized or destabilized by the higher-derivative terms. We then compute these higher-derivative terms explicitly for the type IIB string compactified on a Calabi-Yau orientifold with fluxes via Kaluza-Klein reducing the (α'){sup 3}R{sup 4} corrections in ten dimensions for the respective N=1 Kaehler moduli sector. We prove that together with flux and the known (α'){sup 3}-corrections the higher-derivative term stabilizes all Calabi-Yau manifolds with positive Euler number, provided the sign of the new correction is negative.

  10. Young's moduli of cables for high field superconductive dipole magnet

    International Nuclear Information System (INIS)

    Yamada, Shunji; Shintomi, Takakazu.

    1983-01-01

    Superconductive dipole magnets for big accelerators are subjected to enormous electro-magnetic force, when they are operated with high field such as 10 Tesla. They should be constructed by means of superconductive cables, which have high Young's modulus, to obtain good performance. To develop such cables we measured the Young's moduli of cables for practical use of accelerator magnets. They are monolithic and compacted strand cables. We measured also Young's moduli of monolithic copper and brass cables for comparison. The obtained data showed the Young's moduli of 35 and 15 GPa for the monolithic and compacted strand cables, respectively. (author)

  11. Higgs, moduli problem, baryogenesis and large volume compactifications

    Energy Technology Data Exchange (ETDEWEB)

    Higaki, Tetsutaro [RIKEN Nishina Center, Saitama (Japan). Mathematical Physics Lab.; Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Takahashi, Fuminobu [Tohoku Univ., Sendai (Japan). Dept. of Physics

    2012-07-15

    We consider the cosmological moduli problem in the context of high-scale supersymmetry breaking suggested by the recent discovery of the standard-model like Higgs boson. In order to solve the notorious moduli-induced gravitino problem, we focus on the LARGE volume scenario, in which the modulus decay into gravitinos can be kinematically forbidden. We then consider the Affleck-Dine mechanism with or without an enhanced coupling with the inflaton, taking account of possible Q-ball formation. We show that the baryon asymmetry of the present Universe can be generated by the Affleck-Dine mechanism in LARGE volume scenario, solving the moduli and gravitino problems.

  12. Higgs, moduli problem, baryogenesis and large volume compactifications

    International Nuclear Information System (INIS)

    Higaki, Tetsutaro; Takahashi, Fuminobu

    2012-07-01

    We consider the cosmological moduli problem in the context of high-scale supersymmetry breaking suggested by the recent discovery of the standard-model like Higgs boson. In order to solve the notorious moduli-induced gravitino problem, we focus on the LARGE volume scenario, in which the modulus decay into gravitinos can be kinematically forbidden. We then consider the Affleck-Dine mechanism with or without an enhanced coupling with the inflaton, taking account of possible Q-ball formation. We show that the baryon asymmetry of the present Universe can be generated by the Affleck-Dine mechanism in LARGE volume scenario, solving the moduli and gravitino problems.

  13. Moduli of Parabolic Higgs Bundles and Atiyah Algebroids

    DEFF Research Database (Denmark)

    Logares, Marina; Martens, Johan

    2010-01-01

    In this paper we study the geometry of the moduli space of (non-strongly) parabolic Higgs bundles over a Riemann surface with marked points. We show that this space possesses a Poisson structure, extending the one on the dual of an Atiyah algebroid over the moduli space of parabolic vector bundles....... By considering the case of full flags, we get a Grothendieck–Springer resolution for all other flag types, in particular for the moduli spaces of twisted Higgs bundles, as studied by Markman and Bottacin and used in the recent work of Laumon–Ngô. We discuss the Hitchin system, and demonstrate that all...

  14. New moduli spaces from string background independence consistency conditions

    International Nuclear Information System (INIS)

    Zwiebach, B.

    1996-01-01

    In string field theory an infinitesimal background deformation is implemented as a canonical transformation whose hamiltonian function is defined by moduli spaces of punctured Riemann surfaces having one special puncture. We show that the consistency conditions associated to the commutator of two deformations are implemented by virtue of the existence of moduli spaces of punctured surfaces with two special punctures. The spaces are antisymmetric under the exchange of the special punctures, and satisfy recursion relations relating them to moduli spaces with one special puncture and to string vertices. We develop the theory of moduli spaces of surfaces with arbitrary number of special punctures and indicate their relevance to the construction of a string field theory that makes no reference to a conformal background. Our results also imply a partial antibracket cohomology theorem for the string action. (orig.)

  15. On the moduli space of superminimal surfaces in spheres

    Directory of Open Access Journals (Sweden)

    Luis Fernández

    2003-01-01

    Full Text Available Using a birational correspondence between the twistor space of S2n and projective space, we describe, up to birational equivalence, the moduli space of superminimal surfaces in S2n of degree d as curves of degree d in projective space satisfying a certain differential system. Using this approach, we show that the moduli space of linearly full maps is nonempty for sufficiently large degree and we show that the dimension of this moduli space for n=3 and genus 0 is greater than or equal to 2d+9. We also give a direct, simple proof of the connectedness of the moduli space of superminimal surfaces in S2n of degree d.

  16. Moduli spaces of curves and enumerative geometry via topological recursion

    NARCIS (Netherlands)

    Lewański, D.

    2017-01-01

    The thesis considers several enumerative geometric problems concerning the topology of the moduli space of curves and their combinatorics. These enumerative geometric problems are analysed from different intertwined points of view and using different mathematical tools, including Hurwitz theory,

  17. Aspects of Moduli Stabilization in Type IIB String Theory

    Directory of Open Access Journals (Sweden)

    Shaaban Khalil

    2016-01-01

    Full Text Available We review moduli stabilization in type IIB string theory compactification with fluxes. We focus on KKLT and Large Volume Scenario (LVS. We show that the predicted soft SUSY breaking terms in KKLT model are not phenomenological viable. In LVS, the following result for scalar mass, gaugino mass, and trilinear term is obtained: m0=m1/2=-A0=m3/2, which may account for Higgs mass limit if m3/2~O(1.5 TeV. However, in this case, the relic abundance of the lightest neutralino cannot be consistent with the measured limits. We also study the cosmological consequences of moduli stabilization in both models. In particular, the associated inflation models such as racetrack inflation and Kähler inflation are analyzed. Finally, the problem of moduli destabilization and the effect of string moduli backreaction on the inflation models are discussed.

  18. Successfully combining SUGRA hybrid inflation and moduli stabilisation

    International Nuclear Information System (INIS)

    Davis, S.C.

    2008-01-01

    Inflation and moduli stabilisation mechanisms work well independently, and many string-motivated supergravitymodels have been proposed for them. However a complete theory will contain both, and there will be (gravitational) interactions between the two sectors. These give corrections to the inflaton potential, which generically ruin inflation. This holds true even for fine-tuned moduli stabilisation schemes. We show that a viable combined model can be obtained if it is the Kaehler functions (G=K+ln vertical stroke W vertical stroke 2 ) of the two sectors that are added, rather than the superpotentials (as is usually done). Interaction between the two sectors does still impose some restrictions on the moduli stabilisation mechanism, which are derived. Significantly, we find that the (post-inflation) moduli stabilisation scale no longer needs to be above the inflationary energy scale. (orig.)

  19. Fields generated by sums and products of singular moduli

    OpenAIRE

    Faye, Bernadette; Riffaut, Antonin

    2017-01-01

    We show that the field $\\mathbb{Q}(x,y)$, generated by two singular moduli~$x$ and~$y$, is generated by their sum ${x+y}$, unless~$x$ and~$y$ are conjugate over~$\\mathbb{Q}$, in which case ${x+y}$ generates a subfield of degree at most~$2$. We obtain a similar result for the product of two singular moduli.

  20. On D-brane dynamics and moduli stabilization

    Science.gov (United States)

    Kitazawa, Noriaki

    2017-09-01

    We discuss the effect of the dynamics of D-branes on moduli stabilization in type IIB string theory compactifications, with reference to a concrete toy model of T6/Z 3 orientifold compactification with fractional D3-branes and anti-D3-branes at orbifold fixed points. The resulting attractive forces between anti-D3-branes and D3-branes, together with the repulsive forces between anti-D3-branes and O3-planes, can affect the stability of the compact space. There are no complex structure moduli in T6/Z 3 orientifold, which should thus capture some generic features of more general settings where all complex structure moduli are stabilized by three-form fluxes. The simultaneous presence of branes and anti-branes brings along the breaking of supersymmetry. Non-BPS combinations of this type are typical of “brane supersymmetry breaking” and are a necessary ingredient in the KKLT scenario for stabilizing the remaining Kähler moduli. The conclusion of our analysis is that, while mutual D-brane interactions sometimes help Kähler moduli stabilization, this is not always the case.

  1. Moduli vacuum misalignment and precise predictions in string inflation

    Energy Technology Data Exchange (ETDEWEB)

    Cicoli, Michele [Dipartimento di Fisica ed Astronomia, Università di Bologna,via Irnerio 46, 40126 Bologna (Italy); INFN sezione di Bologna,viale Berti Pichat 6/2, 40127 Bologna (Italy); Abdus Salam ICTP,Strada Costiera 11, Trieste 34014 (Italy); Dutta, Koushik [Theory Division, Saha Institute of Nuclear Physics,1/AF Salt Lake, Kolkata 700064 (India); Maharana, Anshuman [Harish Chandra Research Intitute,Chattnag Road, Jhunsi, Allahabad 211019 (India); Quevedo, Fernando [Abdus Salam ICTP,Strada Costiera 11, Trieste 34014 (Italy); DAMTP, University of Cambridge,Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)

    2016-08-03

    The predictions for all the cosmological observables of any inflationary model depend on the number of e-foldings which is sensitive to the post-inflationary history of the universe. In string models the generic presence of light moduli leads to a late-time period of matter domination which lowers the required number of e-foldings and, in turn, modifies the exact predictions of any inflationary model. In this paper we compute exactly the shift of the number of e-foldings in Kähler moduli inflation which is determined by the magnitude of the moduli initial displacement caused by vacuum misalignment and the moduli decay rates. We find that the preferred number of e-foldings gets reduced from 50 to 45, causing a modification of the spectral index at the percent level. Our results illustrate the importance of understanding the full post-inflationary evolution of the universe in order to derive precise predictions in string inflation. To perform this task it is crucial to work in a setting where there is good control over moduli stabilisation.

  2. Effect of TeO2 on the elastic moduli of sodium borate glasses

    International Nuclear Information System (INIS)

    Saddeek, Y.B.; Abd El Latif, Lamia

    2004-01-01

    Sodium borate glass containing tellurite as Te x Na 2-2x B 4-4x O 7-5x with x=0, 0.05, 0.15, 0.25 and 0.35 have been prepared by rapid quenching. Ultrasonic velocity (both longitudinal and shear) measurements have been made using a transducer operated at the fundamental frequency of 4 MHz at room temperature. The density was measured by the conventional Archimedes method. The elastic moduli, the Debye temperature, Poisson's ratio, and the parameters derived from the Makishima-Mackenzie model and the bond compression model have been obtained as a function of TeO 2 content. The monotonic decrease in the velocities and the elastic moduli, and the increase in the ring diameter and the ratio K bc /K e as a function of TeO 2 modifier content reveals the loose packing structure, which is attributed to the increase in the molar volume and the reduction in the vibrations of the borate lattice. The observed results confirm that the addition of TeO 2 changes the rigid character of Na 2 B 4 O 7 to a matrix of ionic behaviour bonds (NBOs). This is due to the creation of more and more discontinuities and defects in the glasses, thus breaking down the borax structure

  3. Information metric on instanton moduli spaces in nonlinear σ models

    International Nuclear Information System (INIS)

    Yahikozawa, Shigeaki

    2004-01-01

    We study the information metric on instanton moduli spaces in two-dimensional nonlinear σ models. In the CP 1 model, the information metric on the moduli space of one instanton with the topological charge Q=k(k≥1) is a three-dimensional hyperbolic metric, which corresponds to Euclidean anti-de Sitter space-time metric in three dimensions, and the overall scale factor of the information metric is 4k 2 /3; this means that the sectional curvature is -3/4k 2 . We also calculate the information metric in the CP 2 model

  4. Cautionary remarks on the moduli space metric for multidyon simulations

    International Nuclear Information System (INIS)

    Bruckmann, Falk; Dinter, Simon; Ilgenfritz, Ernst-Michael; Mueller-Preussker, Michael; Wagner, Marc

    2009-01-01

    We perform a detailed numerical investigation of the approximate moduli space metric proposed by Diakonov and Petrov [Phys. Rev. D 76, 056001 (2007)] for a confining model of dyons. Our findings strongly indicate that this metric is positive definite (and, therefore, a valid moduli space metric) throughout a considerable part of configuration space only for a small number of dyons at sufficiently low density. This poses strong limitations on results obtained by an unrestricted integration over collective coordinates in this model. It also indicates that strong correlations between collective coordinates will be essential for the physical content of a dyon model, which could be exhibited by a suitable simulation algorithm.

  5. CP violation and moduli stabilization in heterotic models

    International Nuclear Information System (INIS)

    Giedt, Joel

    2002-01-01

    The role of moduli stabilization in predictions for CP violation is examined in the context of four-dimensional effective supergravity models obtained from the weakly coupled heterotic string. They point out that while stabilization of compactification moduli has been studied extensively, the determination of background values for other scalar by dynamical means has not been subjected to the same degree of scrutiny. These other complex scalars are important potential sources of CP violation and they show in a simple model how their background values (including complex phases) may be determined from the minimization of the supergravity scalar potential, subject to the constraint of vanishing cosmological constant

  6. Duality Group for Calabi-Yau 2-Moduli Space

    OpenAIRE

    Ceresole, A.; D'Auria, R.; Regge, T.

    1993-01-01

    We present an efficient method for computing the duality group $\\Gamma$ of the moduli space \\cM for strings compactified on a Calabi-Yau manifold described by a two-moduli deformation of the quintic polynomial immersed in $\\CP(4)$, $\\cW={1\\over5}(\\iy_1^5+\\cdots+\\iy_5^5)-a\\,\\iy_4^3 \\iy_5^2 -b\\, \\iy_4^2 \\iy_5^3$. We show that $\\Gamma$ is given by a $3$--dimensional representation of a central extension of $B_5$, the braid group on five strands.

  7. Polycrystalline gamma plutonium's elastic moduli versus temperature

    Energy Technology Data Exchange (ETDEWEB)

    Migliori, Albert [Los Alamos National Laboratory; Betts, J [Los Alamos National Laboratory; Trugman, A [Los Alamos National Laboratory; Mielke, C H [Los Alamos National Laboratory; Mitchell, J N [Los Alamos National Laboratory; Ramos, M [Los Alamos National Laboratory; Stroe, I [WORCESTER POLYTECHNIC INSTITUTE

    2009-01-01

    Resonant ultrasound spectroscopy was used to measure the elastic properties of pure polycrystalline {sup 239}Pu in the {gamma} phase. Shear and longitudinal elastic moduli were measured simultaneously and the bulk modulus was computed from them. A smooth, linear, and large decrease of all elastic moduli with increasing temperature was observed. They calculated the Poisson ratio and found that it increases from 0.242 at 519 K to 0.252 at 571 K. These measurements on extremely well characterized pure Pu are in agreement with other reported results where overlap occurs.

  8. The stable moduli space of Riemann surfaces: Mumford's conjecture

    DEFF Research Database (Denmark)

    Madsen, I.; Weiss, Michael

    2007-01-01

    , one may replace the stable moduli space of Riemann surfaces by $B\\Gamma_{\\infty}$, where $\\Gamma_\\infty$ is the group of isotopy classes of automorphisms of a smooth oriented connected surface of ``large'' genus. Tillmann's theorem that the plus construction makes $B\\Gamma_{\\infty}$ into an infinite...

  9. Intermediate Jacobians and Hodge structures of moduli spaces

    Indian Academy of Sciences (India)

    The mixed Hodge structure on the low degree cohomology of the moduli space of vector bundles on a curve is studied. Analysis of the third cohomology yields a new proof of a Torelli theorem. Author Affiliations. Donu Arapura1 Pramathanath Sastry1 2. Department of Mathematics, Purdue University, West Lafayette, ...

  10. Infinite Grassmannian and moduli space of G-bundles

    International Nuclear Information System (INIS)

    Kumar, S.; Ramanathan, A.

    1993-03-01

    Let C be a smooth irreducible projective curve and G a simply connected simple affine algebraic group of C. We study in this paper the relationship between the space of vacua defined in Conformal Field Theory and the space of sections of a line bundle on the moduli space of G-bundles over C. (author). 33 refs

  11. Moduli space for endomorphisms of finite dimension vector spaces

    International Nuclear Information System (INIS)

    Kanarek, H.

    1990-12-01

    Consider the set (End n ) of endomorphisms of vector spaces of dimension n n ). What we present here is a decomposition of (End n ) in which each element has a fine moduli space and one of them is composed by the semisimple endomorphisms as D. Mumford shows. (author). 2 refs

  12. Moduli and (un)attractor black hole thermodynamics

    NARCIS (Netherlands)

    Astefanesei, D.; Goldstein, K.D.; Mahapatra, S.

    2008-01-01

    We investigate four-dimensional spherically symmetric black hole solutions in gravity theories with massless, neutral scalars non-minimally coupled to gauge fields. In the non-extremal case, we explicitly show that, under the variation of the moduli, the scalar charges appear in the first law of

  13. Stability of Picard Bundle Over Moduli Space of Stable Vector ...

    Indian Academy of Sciences (India)

    Abstract. Answering a question of [BV] it is proved that the Picard bundle on the moduli space of stable vector bundles of rank two, on a Riemann surface of genus at least three, with fixed determinant of odd degree is stable.

  14. On moduli of convexity and some applications | Barcenas ...

    African Journals Online (AJOL)

    Abstract. We provide some properties of both moduli of convexity δ and β and derive some applications of the modulus β to the geometry of Banach spaces as well as fixed point theory. Quaestiones Mathematicae 32(2009), 307–319 ...

  15. Quantum cohomology of moduli spaces of genus zero stable curves

    OpenAIRE

    Fontanari, Claudio

    2007-01-01

    We investigate the (small) quantum cohomology ring of the moduli spaces of stable n-pointed curves of genus 0. In particular, we determine an explicit presentation in the case n=5 and we outline a computational approach to the case n=6.

  16. Moduli for decorated tuples of sheaves and representation spaces ...

    Indian Academy of Sciences (India)

    We extend the scope of a former paper to vector bundle problems involving more than one vector bundle. As the main application, we obtain the solution of the well-known moduli problems of vector bundles associated with general quivers. Author Affiliations. Alexander Schmitt1. Universität Duisburg-Essen, Campus Essen, ...

  17. Moduli space of Parabolic vector bundles over hyperelliptic curves

    Indian Academy of Sciences (India)

    27

    MODULI SPACE OF PARABOLIC VECTOR BUNDLES OVER. HYPERELLIPTIC CURVES. SURATNO BASU AND SARBESWAR PAL. Abstract. Let X be a smooth projective hyperelliptic curve of arbitrary genus g. In this short article we will classify the rank 2 stable vector bundles with parabolic structure along a reduced ...

  18. Bounds on Scalar Masses in Theories of Moduli Stabilization

    CERN Document Server

    Acharya, Bobby Samir; Kuflik, Eric

    2014-01-01

    In recent years it has been realised that pre-BBN decays of moduli can be a significant source of dark matter production, giving a `non-thermal WIMP miracle' and substantially reduced fine-tuning in cosmological axion physics. We study moduli masses and sharpen the claim that moduli dominated the pre-BBN Universe. We conjecture that in any string theory with stabilized moduli there will be at least one modulus field whose mass is of order (or less than) the gravitino mass and we prove this for a large class of models based on Calabi-Yau extra dimensions. Cosmology then generically requires the gravitino mass not be less than about 30 TeV and the cosmological history of the Universe is non-thermal prior to BBN. Stable LSP's produced in these decays can account for the observed dark matter if they are `wino-like,' which is consistent with the PAMELA data for positrons and antiprotons. With WIMP dark matter, there is an upper limit on the gravitino mass of order 250 TeV. We briefly consider implications for the ...

  19. Bohr--Sommerfeld Lagrangians of moduli spaces of Higgs bundles

    DEFF Research Database (Denmark)

    Biswas, Indranil; Gammelgaard, Niels Leth; Logares, Marina

    Let $X$ be a compact connected Riemann surface of genus at least two. Let $M_H(r,d)$ denote the moduli space of semistable Higgs bundles on $X$ of rank $r$ and degree $d$. We prove that the compact complex Bohr-Sommerfeld Lagrangians of $M_H(r,d)$ are precisely the irreducible components of the n...

  20. On rationality of moduli spaces of vector bundles on real Hirzebruch ...

    Indian Academy of Sciences (India)

    Introduction. Moduli spaces of semistable vector bundles on a smooth projective variety are studied from various points of view. One of the questions that is often addressed is the birational type of the moduli space, more precisely, the question of rationality. It is known that the moduli space of semistable vector bundles of ...

  1. Probing the moduli dependence of refined topological amplitudes

    Directory of Open Access Journals (Sweden)

    I. Antoniadis

    2015-12-01

    Full Text Available With the aim of providing a worldsheet description of the refined topological string, we continue the study of a particular class of higher derivative couplings Fg,n in the type II string effective action compactified on a Calabi–Yau threefold. We analyse first order differential equations in the anti-holomorphic moduli of the theory, which relate the Fg,n to other component couplings. From the point of view of the topological theory, these equations describe the contribution of non-physical states to twisted correlation functions and encode an obstruction for interpreting the Fg,n as the free energy of the refined topological string theory. We investigate possibilities of lifting this obstruction by formulating conditions on the moduli dependence under which the differential equations simplify and take the form of generalised holomorphic anomaly equations. We further test this approach against explicit calculations in the dual heterotic theory.

  2. IMPA-ICTP School on Moduli of Curves

    CERN Document Server

    Ciliberto, Ciro; Esteves, Eduardo; Melo, Margarida; Voisin, Claire

    2017-01-01

    Providing a timely description of the present state of the art of moduli spaces of curves and their geometry, this volume is written in a way which will make it extremely useful both for young people who want to approach this important field, and also for established researchers, who will find references, problems, original expositions, new viewpoints, etc. The book collects the lecture notes of a number of leading algebraic geometers and in particular specialists in the field of moduli spaces of curves and their geometry. This is an important subject in algebraic geometry and complex analysis which has seen spectacular developments in recent decades, with important applications to other parts of mathematics such as birational geometry and enumerative geometry, and to other sciences, including physics.  The themes treated are classical but with a constant look to modern developments (see Cascini, Debarre, Farkas, and Sernesi's contributions), and include very new material, such as Bridgeland stability (see M...

  3. Graph Complexes and the Moduli Space of Riemann Surfaces

    DEFF Research Database (Denmark)

    Egas Santander, Daniela

    In this thesis we compare several combinatorial models for the moduli space of open-closed cobordisms and their compactifications. More precisely, we study Godin's category of admissible fat graphs, Costello's chain complex of black and white graphs, and Bödigheimer's space of radial slit......, that the complex of black and white graphs is a homological model of this mapping class group. Beyond giving new proofs of these results, the methods used give a new interpretation of Costello's model in terms of admissible fat graphs, which is a more classical model of moduli space. This connection could...... potentially allow to transfer constructions in fat graphs to the black and white model. Moreover, we compare Bödigheimer's radial slit configurations and the space of metric admissible fat graphs, producing an explicit homotopy equivalence using a "critical graph" map. This critical graph map descends...

  4. In Silico Measurement of Elastic Moduli of Nematic Liquid Crystals

    Science.gov (United States)

    Sidky, Hythem; de Pablo, Juan J.; Whitmer, Jonathan K.

    2018-03-01

    Experiments on confined droplets of the nematic liquid crystal 5CB have questioned long-established bounds imposed on the elastic free energy of nematic systems. This elasticity, which derives from molecular alignment within nematic systems, is quantified through a set of moduli which can be difficult to measure experimentally and, in some cases, can only be probed indirectly. This is particularly true of the surfacelike saddle-splay elastic term, for which the available experimental data indicate values on the cusp of stability, often with large uncertainties. Here, we demonstrate that all nematic elastic moduli, including the saddle-splay elastic constant k24, may be calculated directly from atomistic molecular simulations. Importantly, results obtained through in silico measurements of the 5CB elastic properties demonstrate unambiguously that saddle-splay elasticity alone is unable to describe the observed confined morphologies.

  5. Structures and Elastic Moduli of Polymer Nanocomposite Thin Films

    Science.gov (United States)

    Yuan, Hongyi; Karim, Alamgir; University of Akron Team

    2014-03-01

    Polymeric thin films generally possess unique mechanical and thermal properties due to confinement. In this study we investigated structures and elastic moduli of polymer nanocomposite thin films, which can potentially find wide applications in diverse areas such as in coating, permeation and separation. Conventional thermoplastics (PS, PMMA) and biopolymers (PLA, PCL) were chosen as polymer matrices. Various types of nanoparticles were used including nanoclay, fullerene and functionalized inorganic particles. Samples were prepared by solvent-mixing followed by spin-coating or flow-coating. Film structures were characterized using X-ray scattering and transmission electron microscopy. Elastic moduli were measured by strain-induced elastic buckling instability for mechanical measurements (SIEBIMM), and a strengthening effect was found in certain systems due to strong interaction between polymers and nanoparticles. The effects of polymer structure, nanoparticle addition and film thickness on elastic modulus will be discussed and compared with bulk materials.

  6. No-scale D-term inflation with stabilized moduli

    International Nuclear Information System (INIS)

    Buchmueller, Wilfried; Domcke, Valerie; Wieck, Clemens

    2013-09-01

    We study the consistency of hybrid inflation and moduli stabilization, using the Kallosh- Linde model as an example for the latter. We find that F-term hybrid inflation is not viable since inflationary trajectories are destabilized by tachyonic modes. On the other hand, D-term hybrid inflation is naturally compatible with moduli stabilization due to the absence of a large superpotential term during the inflationary phase. Our model turns out to be equivalent to superconformal D-term inflation and it therefore successfully accounts for the CMB data in the large-field regime. Supersymmetry breaking can be incorporated via an O'Raifeartaigh model. For GUT-scale inflation one obtains a stringent bound on the gravitino mass. A rough estimate yields m 3/2 >or similar 10 5 GeV, contrary to naive expectation.

  7. The Hilbert Series of the One Instanton Moduli Space

    CERN Document Server

    Benvenuti, Sergio; Mekareeya, Noppadol; 10.1007

    2010-01-01

    The moduli space of k G-instantons on R^4 for a classical gauge group G is known to be given by the Higgs branch of a supersymmetric gauge theory that lives on Dp branes probing D(p + 4) branes in Type II theories. For p = 3, these (3 + 1) dimensional gauge theories have N = 2 supersymmetry and can be represented by quiver diagrams. The F and D term equations coincide with the ADHM construction. The Hilbert series of the moduli spaces of one instanton for classical gauge groups is easy to compute and turns out to take a particularly simple form which is previously unknown. This allows for a G invariant character expansion and hence easily generalisable for exceptional gauge groups, where an ADHM construction is not known. The conjectures for exceptional groups are further checked using some new techniques like sewing relations in Hilbert Series. This is applied to Argyres-Seiberg dualities.

  8. Instantons from geodesics in AdS moduli spaces

    Science.gov (United States)

    Ruggeri, Daniele; Trigiante, Mario; Van Riet, Thomas

    2018-03-01

    We investigate supergravity instantons in Euclidean AdS5 × S5/ℤk. These solutions are expected to be dual to instantons of N = 2 quiver gauge theories. On the supergravity side the (extremal) instanton solutions are neatly described by the (lightlike) geodesics on the AdS moduli space for which we find the explicit expression and compute the on-shell actions in terms of the quantised charges. The lightlike geodesics fall into two categories depending on the degree of nilpotency of the Noether charge matrix carried by the geodesic: for degree 2 the instantons preserve 8 supercharges and for degree 3 they are non-SUSY. We expect that these findings should apply to more general situations in the sense that there is a map between geodesics on moduli-spaces of Euclidean AdS vacua and instantons with holographic counterparts.

  9. The Coulomb Branch Formula for Quiver Moduli Spaces

    CERN Document Server

    Manschot, Jan; Sen, Ashoke

    2014-01-01

    In recent series of works, by translating properties of multi-centered supersymmetric black holes into the language of quiver representations, we proposed a formula that expresses the Hodge numbers of the moduli space of semi-stable representations of quivers with generic superpotential in terms of a set of invariants associated to `single-centered' or `pure-Higgs' states. The distinguishing feature of these invariants is that they are independent of the choice of stability condition. Furthermore they are uniquely determined by the $\\chi_y$-genus of the moduli space. Here, we provide a self-contained summary of the Coulomb branch formula, spelling out mathematical details but leaving out proofs and physical motivations.

  10. On natural inflation and moduli stabilisation in string theory

    Energy Technology Data Exchange (ETDEWEB)

    Palti, Eran [Institut für Theoretische Physik, Ruprecht-Karls-Universität, Philosophenweg 19, Heidelberg, 69120 (Germany)

    2015-10-28

    Natural inflation relies on the existence of an axion decay constant which is super-Planckian. In string theory only sub-Planckian axion decay constants have been found in any controlled regime. However in field theory it is possible to generate an enhanced super-Planckian decay constant by an appropriate aligned mixing between axions with individual sub-Planckian decay constants. We study the possibility of such a mechanism in string theory. In particular we construct a new realisation of an alignment scenario in type IIA string theory compactifications on a Calabi-Yau where the alignment is induced through fluxes. Within field theory the original decay constants are taken to be independent of the parameters which induce the alignment. In string theory however they are moduli dependent quantities and so interact gravitationally with the physics responsible for the mixing. We show that this gravitational effect of the fluxes on the moduli can precisely cancel any enhancement of the effective decay constant. This censorship of an effective super-Planckian decay constant depends on detailed properties of Calabi-Yau moduli spaces and occurs for all the examples and classes that we study. We expand these results to a general superpotential assuming only that the axion superpartners are fixed supersymmetrically and are able to show for a large class of Calabi-Yau manifolds, but not all, that the cancellation effect occurs and is independent of the superpotential. We also study simple models where the moduli are fixed non-supersymmetrically and find that similar cancellation behaviour can emerge. Finally we make some comments on a possible generalisation to axion monodromy inflation models.

  11. Von Neuman representations on self-dual Hilbert W* moduli

    International Nuclear Information System (INIS)

    Frank, M.

    1987-01-01

    Von Neumann algebras M of bounded operators on self-dual Hilbert W* moduli H possessing a cyclic-separating element x-bar in H are considered. The close relation of them to certain real subspaces of H is established. Under the supposition that the underlying W*-algebra is commutative, a Tomita-Takesaki type theorem is stated. The natural cone in H arising from the pair (M, x-bar) is investigated and its properties are obtained

  12. On Rationality of Moduli Spaces of Vector Bundles on Real ...

    Indian Academy of Sciences (India)

    Let be a real form of a Hirzebruch surface. Let M H ( r , c 1 , c 2 ) be the moduli space of vector bundles on . Under some numerical conditions on r , c 1 and c 2 , we identify those M H ( r , c 1 , c 2 ) that are rational. Author Affiliations. Indranil Biswas1 Ronnie Sebastian2. School of Mathematics, Tata Institute of ...

  13. Picard groups of the moduli spaces of semistable sheaves I

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    This completes the extension of results of [6] to nodal curves. Let U = U(n,d) denote the moduli space of torsion-free sheaves of rank n and degree d on Y. If Y has only a single ordinary node as singularity, then the variety U(2,d) has a stratification, U = U ∪ U1 ∪ U0, a disjoint union. Points of U1 correspond to torsion-free.

  14. Elastic moduli and crosslinking of some tellurite glass systems

    Energy Technology Data Exchange (ETDEWEB)

    El-Mallawany, R., E-mail: raoufelmallawany@Yahoo.com [Physics Dept., Science College, Northern Boarders University (Saudi Arabia); Afifi, H. [National Institute for Standards, Giza (Egypt)

    2013-12-16

    Tellurite glass systems in the form 80(TeO{sub 2})–5(TiO{sub 2})–(15 − x)(WO{sub 3})–(x)A{sub n}O{sub m} have been prepared by the melt quenching technique. The A{sub n}O{sub m} oxide was Nb{sub 2}O{sub 5} or Nd{sub 2}O{sub 3} or Er{sub 2}O{sub 3} and x ≤ 5 mol%. Density and Molar volume have been determined for the prepared glasses. Both longitudinal and shear ultrasonic velocities were measured in different compositions of the glass system by using the pulse-echo method at 5 MHz frequency and at room temperature. Ultrasonic velocity and density data have been used to calculate elastic moduli (longitudinal modulus L, shear modulus G, Young's modulus E, Bulk modulus K), Poisson's ratio σ, and Debye temperature θ{sub D}. Quantitative analysis of elastic moduli based on the number of bonds per unit volume, average crosslinks and number of vibrating atoms per unit volume has been achieved. - Highlights: • Tellurite glasses. • Elastic moduli, Poisson's ratio, Debye temperature, microhardness. • Number of bonds per unit volume, average crosslinks, number of vibrating atoms per unit volume.

  15. The structure and elastic moduli of flux-line lattices in anisotropic superconductors

    International Nuclear Information System (INIS)

    Grishin, A.M.; Martynovich, A.Yu.; Yampol'skiy, S.V.

    1992-01-01

    The elastic moduli of flux-line lattices in anisotropic superconductors are investigated. In addition to the well-known bulk, shear, and tilt moduli the authors observe moduli that relate deformations in the basal plane of the lattice to vortex tilt. These moduli vanish when the superconductor is magnetized along the axis of anisotropy. The vortex structure continuum realized in this case has identical bulk and shear moduli and different tilt moduli. A hexagonal flux-line lattice is realized in superconductors with 'easy axis' anisotropy when a weak magnetic field is applied. When the field H is applied in the ab-plane of the crystal the lattice becomes an oblique lattice with orthorhombic symmetry. This results in a sharp growth of its elastic moduli and the induction in the sample. Vortex chain structures are the only stable structures in 'easy plane' superconductors. The elastic moduli characterizing the rigidity of an isolated chain are exponentially large compared to the moduli describing interchain interaction. The tilt moduli may reverse their sign when H is oriented near the axis of anisotropy c for strongly anisotropic superconductors. In this case, the vortex structure and all related elastic moduli undergo a discontinuous irreversible change

  16. Moduli stabilization and uplifting with dynamically generated F-terms

    International Nuclear Information System (INIS)

    Dudas, Emilian; Papineau, Chloe; Pokorski, Stefan

    2007-01-01

    We use the F-term dynamical supersymmetry breaking models with metastable vacua in order to uplift the vacuum energy in the KKLT moduli stabilization scenario. The main advantage compared to earlier proposals is the manifest supersymmetric treatment and the natural coexistence of a TeV gravitino mass with a zero cosmological constant. We argue that it is generically difficult to avoid anti de-Sitter supersymmetric minima, however the tunneling rate from the metastable vacuum with zero vacuum energy towards them can be very suppressed. We briefly comment on the properties of the induced soft terms in the observable sector

  17. Moduli stabilization and uplifting with dynamically generated F-terms

    Energy Technology Data Exchange (ETDEWEB)

    Dudas, Emilian [CERN Theory Division, CH-1211, Geneva 23 (Switzerland); Papineau, Chloe [CPhT, Ecole Polytechnique, F-91128 Palaiseau Cedex (France); Pokorski, Stefan [Institute of Theoretical Physics, Univ. of Warsaw, 00-681 Warsaw (Poland)

    2007-02-15

    We use the F-term dynamical supersymmetry breaking models with metastable vacua in order to uplift the vacuum energy in the KKLT moduli stabilization scenario. The main advantage compared to earlier proposals is the manifest supersymmetric treatment and the natural coexistence of a TeV gravitino mass with a zero cosmological constant. We argue that it is generically difficult to avoid anti de-Sitter supersymmetric minima, however the tunneling rate from the metastable vacuum with zero vacuum energy towards them can be very suppressed. We briefly comment on the properties of the induced soft terms in the observable sector.

  18. Ultrasonic velocity and elastic moduli of heavy metal tellurite glasses

    Energy Technology Data Exchange (ETDEWEB)

    Afifi, Hesham; Marzouk, Samier

    2003-05-26

    Longitudinal and transverse ultrasonic waves velocities in lead tungsten tellurite glasses have been measured using the pulse-echo method at 5 MHz frequency and at room temperature (300 K). The elastic properties; longitudinal modulus, shear modulus, Young's modulus, bulk modulus and Poisson's ratio together with the microhardness, softening temperature, and Debye temperature are found to be rather sensitive to the glass composition. Information about the structure of the glass can be deduced after calculating the average stretching force constant and the average ring size. A comparison between the experimental elastic moduli data obtained in this study and those calculated theoretically by other models has been discussed.

  19. Fixing All Moduli in a Simple F-Theory Compactification

    Energy Technology Data Exchange (ETDEWEB)

    Denef, F.

    2005-04-28

    We discuss a simple example of an F-theory compactification on a Calabi-Yau fourfold where background fluxes, together with nonperturbative effects from Euclidean D3 instantons and gauge dynamics on D7 branes, allow us to fix all closed and open string moduli. We explicitly check that the known higher order corrections to the potential, which we neglect in our leading approximation, only shift the results by a small amount. In our exploration of the model, we encounter interesting new phenomena, including examples of transitions where D7 branes absorb O3 planes, while changing topology to preserve the net D3 charge.

  20. Non-minimal gauge mediation and moduli stabilization

    International Nuclear Information System (INIS)

    Jelinski, T.; Lalak, Z.; Pawelczyk, J.

    2010-01-01

    In this Letter we consider U(1) A -gauged Polonyi model with two spurions coupled to a twisted closed string modulus. This offers a consistent setup for metastable SUSY breakdown which allows for moduli stabilization and naturally leads to gauge or hybrid gauge/gravitational mediation mechanism. Due to the presence of the second spurion one can arrange for a solution of the μ and B μ problems in a version of modified Giudice-Masiero mechanism, which works both in the limit of pure gauge mediation and in the mixed regime of hybrid mediation.

  1. Homology of the open moduli space of curves

    DEFF Research Database (Denmark)

    Madsen, Ib Henning

    2012-01-01

    This is a survey on the proof of a generalized version of the Mumford conjecture obtained in joint work with M. Weiss stating that a certain map between some classifying spaces which a priori have different natures induces an isomorphism at the level of integral homology. We also discuss our proof...... of the original Mumford conjecture stating that the stable rational cohomology of the moduli space of Riemann surfaces is a certain polynomial algebra generated by the Mumford–Morita–Miller cohomology classes of even degrees....

  2. Quiver theories for moduli spaces of classical group nilpotent orbits

    Energy Technology Data Exchange (ETDEWEB)

    Hanany, Amihay; Kalveks, Rudolph [Theoretical Physics Group, The Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom)

    2016-06-21

    We approach the topic of Classical group nilpotent orbits from the perspective of the moduli spaces of quivers, described in terms of Hilbert series and generating functions. We review the established Higgs and Coulomb branch quiver theory constructions for A series nilpotent orbits. We present systematic constructions for BCD series nilpotent orbits on the Higgs branches of quiver theories defined by canonical partitions; this paper collects earlier work into a systematic framework, filling in gaps and providing a complete treatment. We find new Coulomb branch constructions for above minimal nilpotent orbits, including some based upon twisted affine Dynkin diagrams. We also discuss aspects of 3d mirror symmetry between these Higgs and Coulomb branch constructions and explore dualities and other relationships, such as HyperKähler quotients, between quivers. We analyse all Classical group nilpotent orbit moduli spaces up to rank 4 by giving their unrefined Hilbert series and the Highest Weight Generating functions for their decompositions into characters of irreducible representations and/or Hall Littlewood polynomials.

  3. Correlations between elastic moduli and properties in bulk metallic glasses

    International Nuclear Information System (INIS)

    Wang Weihua

    2006-01-01

    A survey of the elastic, mechanical, fragility, and thermodynamic properties of bulk metallic glasses (BMGs) and glass-forming liquids is presented. It is found that the elastic moduli of BMGs have correlations with the glass transition temperature, melting temperature, mechanical properties, and even liquid fragility. On the other hand, the elastic constants of available BMGs show a rough correlation with a weighted average of the elastic constants for the constituent elements. Although the theoretical and physical reasons for the correlations are to be clarified, these correlations could assist in understanding the long-standing issues of glass formation and the nature of glass and simulate the work of theorists. Based on the correlation, we show that the elastic moduli can assist in selecting alloying components for controlling the elastic properties and glass-forming ability of the BMGs and thus can guide BMG design. As case study, we report the formation of the families of rare-earth-based BMGs with controllable properties

  4. Thermodynamics and elastic moduli of fluids with steeply repulsive potentials

    Science.gov (United States)

    Heyes, D. M.

    1997-08-01

    Analytic expressions for the thermodynamic properties and elastic moduli of molecular fluids interacting with steeply repulsive potentials are derived using Rowlinson's hard-sphere perturbation treatment which employs a softness parameter, λ specifying the deviation from the hard-sphere potential. Generic potentials of this form might be used to represent the interactions between near-hard-sphere stabilized colloids. Analytic expressions for the equivalent hard-sphere diameter of inverse power [ɛ(σ/r)n where ɛ sets the energy scale and σ the distance scale] exponential and logarithmic potential forms are derived using the Barker-Henderson formula. The internal energies in the hard-sphere limit are predicted essentially exactly by the perturbation approach when compared against molecular dynamics simulation data using the same potentials. The elastic moduli are similarly accurately predicted in the hard-sphere limit, as they are trivially related to the internal energy. The compressibility factors from the perturbation expansion do not compare as favorably with simulation data, and in this case the Carnahan-Starling equation of state prediction using the analytic effective hard-sphere diameter would appear to be a preferable route for this thermodynamic property. A more refined state point dependent definition for the effective hard-sphere diameter is probably required for this property.

  5. On a new compactification of the moduli of vector bundles on a surface

    International Nuclear Information System (INIS)

    Timofeeva, N V

    2008-01-01

    A new compactification of the moduli scheme of Gieseker-stable vector bundles with prescribed Hilbert polynomial on a smooth projective polarized surface (S,H) defined over a field k=k-bar of characteristic zero is constructed. The families of locally free sheaves on the surface S are completed by locally free sheaves on surfaces that are certain modifications of S. The new moduli space has a birational morphism onto the Gieseker-Maruyama moduli space. The case when the Gieseker-Maruyama space is a fine moduli space is considered. Bibliography: 12 titles.

  6. On a new compactification of moduli of vector bundles on a surface. III: Functorial approach

    International Nuclear Information System (INIS)

    Timofeeva, Nadezhda V

    2011-01-01

    A new compactification for the scheme of moduli for Gieseker-stable vector bundles with prescribed Hilbert polynomial on the smooth projective polarized surface (S,L) is constructed. We work over the field k=k-bar of characteristic zero. Families of locally free sheaves on the surface S are completed with locally free sheaves on schemes which are modifications of S. The Gieseker-Maruyama moduli space has a birational morphism onto the new moduli space. We propose the functor for families of pairs 'polarized scheme-vector bundle' with moduli space of such type. Bibliography: 16 titles.

  7. Dynamics of moduli and gaugino condensates in an expanding universe

    International Nuclear Information System (INIS)

    Papineau, C.; Ramos-Sanchez, S.; Postma, M.

    2009-08-01

    We study dynamical moduli stabilization driven by gaugino condensation in supergravity. In the presence of background radiation, there exists a region of initial conditions leading to successful stabilization. We point out that most of the allowed region corresponds to initial Hubble rate H close to the scale of condensation Λ, which is the natural cutoff of the effective theory. We first show that including the condensate dynamics sets a strong bound on the initial conditions. We then find that (complete) decoupling of the condensate happens at H about two orders of magnitude below Λ. This bound implies that in the usual scenario with the condensate integrated out, only the vicinity of the minimum leads to stabilization. Finally, we discuss the effects of thermal corrections. (orig.)

  8. Instanton transition in thermal and moduli deformed de Sitter cosmology

    International Nuclear Information System (INIS)

    Kounnas, Costas; Partouche, Herve

    2008-01-01

    We consider the de Sitter cosmology deformed by the presence of a thermal bath of radiation and/or time-dependent moduli fields. Depending on the parameters, either a first or second-order phase transition can occur. In the first case, an instanton allows a double analytic continuation. It induces a probability to enter the inflationary evolution by tunnel effect from another cosmological solution. The latter starts with a big bang and, in the case the transition does not occur, ends with a big crunch. A temperature duality exchanges the two cosmological branches. In the limit where the pure de Sitter universe is recovered, the tunnel effect reduces to a 'creation from nothing', due to the vanishing of the big bang branch. However, the latter may be viable in some range of the deformation parameter. In the second case, there is a smooth evolution from a big bang to the inflationary phase

  9. Exact moduli space metrics for hyperbolic vortex polygons

    International Nuclear Information System (INIS)

    Krusch, S.; Speight, J. M.

    2010-01-01

    Exact metrics on some totally geodesic submanifolds of the moduli space of static hyperbolic N-vortices are derived. These submanifolds, denoted as Σ n,m , are spaces of C n -invariant vortex configurations with n single vortices at the vertices of a regular polygon and m=N-n coincident vortices at the polygon's center. The geometric properties of Σ n,m are investigated, and it is found that Σ n,n-1 is isometric to the hyperbolic plane of curvature -(3πn) -1 . The geodesic flow on Σ n,m and a geometrically natural variant of geodesic flow recently proposed by Collie and Tong ['The dynamics of Chern-Simons vortices', Phys. Rev. D Part. Fields Gravit. Cosmol. 78, 065013 (2008);e-print arXiv:hep-th/0805.0602] are analyzed in detail.

  10. Graph Complexes and the Moduli Space of Riemann Surfaces

    DEFF Research Database (Denmark)

    Egas Santander, Daniela

    potentially allow to transfer constructions in fat graphs to the black and white model. Moreover, we compare Bödigheimer's radial slit configurations and the space of metric admissible fat graphs, producing an explicit homotopy equivalence using a "critical graph" map. This critical graph map descends...... to a homeomorphism between the Unimodular Harmonic compactification and the space of Sullivan diagrams, which are natural compactifications of the space of radial slit configurations and the space of metric admissible fat graphs, respectively. Finally, we use experimental methods to compute the homology of the chain......In this thesis we compare several combinatorial models for the moduli space of open-closed cobordisms and their compactifications. More precisely, we study Godin's category of admissible fat graphs, Costello's chain complex of black and white graphs, and Bödigheimer's space of radial slit...

  11. Yukawa unification in moduli-dominant SUSY breaking

    International Nuclear Information System (INIS)

    Khalil, S.; Tatsuo Kobayashi

    1997-07-01

    We study Yukawa in string models with moduli-dominant SUSY breaking. This type of SUSY breaking in general leads to non-universal soft masses, i.e. soft scalar masses and gaugino masses. Such non-universality is important for phenomenological aspects of Yukawa unification, i.e., successful electroweak breaking, SUSY corrections to the bottom mass and the branching ratio of b → sγ. We show three regions in the whole parameter space which lead to successful electroweak breaking and allow small SUSY corrections to the bottom mass. For these three regions we investigated the b → sγ decay and mass spectra. (author). 26 refs, 6 figs

  12. The motive of the moduli stack of G-bundles over the universal curve

    Indian Academy of Sciences (India)

    E-mail: dvb@math.purdue.edu. MS received 11 April 2007; revised 27 January 2008. Abstract. We define relative motives in the sense of André. After associating a complex in the derived category of motives to an algebraic stack we study this complex in the case of the moduli of G-bundles varying over the moduli of curves.

  13. Higher genus moduli spaces in closed string field theory

    Science.gov (United States)

    Rahman, Sabbir Ahmed

    1997-10-01

    We provide an overview of covariant closed string field theory, covering briefly the geometry of moduli spaces of Riemann surfaces, conformal field theory in the operator formalism and the Batalin-Vilkovisky formalism. Several important applications are also described including connections on the space of conformal theories, quantum background independence, the ghost-dilaton theorem, and string field theory around non-conformal backgrounds. The proof of the ghost-dilaton theorem in string theory is completed by showing that the coupling constant dependence of the vacuum vertices appearing in the closed string action is given correctly by one-point functions of the ghost-dilaton. To prove this at genus one the formalism required to evaluate off-shell amplitudes on tori is developed. Higher order background independence conditions arising from multiple commutators of background deformations in quantum closed string field theory are analysed. The conditions are shown to amount to a vanishing theorem for ΔS cohomology classes. This holds by virtue of the existence of moduli spaces of higher genus surfaces with two kinds of punctures. Our result is a generalisation of a previous genus zero analysis relevant to the classical theory. The string theory operators /partial,/ [/cal K] and [/cal I] are shown to be expressible as inner derivations of the B-V algebra of string vertices. As a consequence, the recursion relations for the string vertices are found to take the form of a 'geometrical' quantum master equation, [1/over 2]/[[/cal B],[/cal B]/]+/Delta[/cal B]=0, where '[/cal B]' is the sum of string vertices. That the B-V delta operator cannot be an inner derivation on the algebra is also shown. The set of string vertices of non-negative dimension is completed in a consistent manner. As a consequence the string action takes the simple form S=f([/cal B]). That the action satisfies the B-V master equation follows immediately from the recursion relations for the string

  14. Research on differences and correlation between tensile, compression and flexural moduli of cement stabilized macadam

    Directory of Open Access Journals (Sweden)

    Yi Yang

    2017-07-01

    Full Text Available In order to reveal the differences and conversion relations between the tensile, compressive and flexural moduli of cement stabilized macadam, in this paper, we develop a new test method for measuring three moduli simultaneously. By using the materials testing system, we test three moduli of the cement stabilized macadam under different loading rates, propose a flexural modulus calculation formula which considers the shearing effect, reveal the change rules of the tensile, compression and flexural moduli with the loading rate and establish the conversion relationships between the three moduli. The results indicate that: three moduli become larger with the increase of the loading rate, showing a power function pattern; with the shear effect considered, the flexural modulus is increased by 47% approximately over that in the current test method; the tensile and compression moduli of cement stabilized macadam are significantly different. Therefore, if only the compression modulus is used as the structural design parameter of asphalt pavement, there will be a great deviation in the analysis of the load response. In order to achieve scientific design and calculation, the appropriate design parameters should be chosen based on the actual stress state at each point inside the pavement structure.

  15. Moduli vacuum bubbles produced by evaporating black holes

    International Nuclear Information System (INIS)

    Morris, J. R.

    2007-01-01

    We consider a model with a toroidally compactified extra dimension giving rise to a temperature-dependent 4D effective potential with one-loop contributions due to the Casimir effect, along with a 5D cosmological constant. The forms of the effective potential at low and high temperatures indicate a possibility for the formation of a domain wall bubble, formed by the modulus scalar field, surrounding an evaporating black hole. This is viewed as an example of a recently proposed black hole vacuum bubble arising from matter-sourced moduli fields in the vicinity of an evaporating black hole [D. Green, E. Silverstein, and D. Starr, Phys. Rev. D 74, 024004 (2006)]. The black hole bubble can be highly opaque to lower-energy particles and photons, and thereby entrap them within. For high-temperature black holes, there may also be a symmetry-breaking black hole bubble of false vacuum of the type previously conjectured by Moss [I. G. Moss, Phys. Rev. D 32, 1333 (1985)], tending to reflect low-energy particles from its wall. A double bubble composed of these two different types of bubble may form around the black hole, altering the hole's emission spectrum that reaches outside observers. Smaller mass black holes that have already evaporated away could have left vacuum bubbles behind that contribute to the dark matter

  16. Hilbert series and moduli spaces of kU(N) vortices

    Energy Technology Data Exchange (ETDEWEB)

    Hanany, Amihay [Theoretical Physics Group, The Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom); Seong, Rak-Kyeong [School of Physics, Korea Institute for Advanced Study,85 Hoegi-ro, Seoul 130-722 (Korea, Republic of)

    2015-02-02

    We study the moduli spaces of kU(N) vortices which are realized by the Higgs branch of a U(k) supersymmetric gauge theory. The theory has 4 supercharges and lives on k D1-branes in a N D3- and NS5-brane background. We realize the vortex moduli space as a ℂ{sup ∗} projection of the vortex master space. The Hilbert series is calculated in order to characterize the algebraic structure of the vortex master space and to identify the precise ℂ{sup ∗} projection. As a result, we are able to fully classify the moduli spaces up to 3 vortices.

  17. On the fine Simpson moduli spaces of 1-dimensional sheaves supported on plane quartics

    Directory of Open Access Journals (Sweden)

    Iena Oleksandr

    2018-02-01

    Full Text Available A parametrization of the fine Simpson moduli spaces of 1-dimensional sheaves supported on plane quartics is given: we describe the gluing of the Brill-Noether loci described by Drézet and Maican, provide a common parameter space for these loci, and show that the Simpson moduli space M = M4m ± 1(ℙ2 is a blow-down of a blow-up of a projective bundle over a smooth moduli space of Kronecker modules. Two different proofs of this statement are given.

  18. Explicit Gromov-Hausdorff compactifications of moduli spaces of Kähler-Einstein Fano manifolds

    DEFF Research Database (Denmark)

    Spotti, Cristiano; Sun, Song

    We exhibit the first non-trivial concrete examples of Gromov-Hausdorff compactifications of moduli spaces of Kähler-Einstein Fano manifolds in all complex dimensions bigger than two (Fano K-moduli spaces). We also discuss potential applications to explicit study of moduli spaces of K-stable Fano ...... manifolds with large anti-canonical volume. Our arguments are based on recent progress about the geometry of metric tangent cones and on related ideas about the algebro-geometric study of singularities of K-stable Fano varieties....

  19. Moduli Potentials in Type IIA Compactifications with RR and NS Flux

    Energy Technology Data Exchange (ETDEWEB)

    Kachru, S.

    2004-12-01

    We describe a simple class of type IIA string compactifications on Calabi-Yau manifolds where background fluxes generate a potential for the complex structure moduli, the dilaton, and the Kaehler moduli. This class of models corresponds to gauged {Nu} = 2 supergravities, and the potential is completely determined by a choice of gauging and by data of the {Nu} = 2 Calabi-Yau model--the prepotential for vector multiplets and the quaternionic metric on the hypermultiplet moduli space. Using mirror symmetry, one can determine many (though not all) of the quantum corrections which are relevant in these models.

  20. Deformations, moduli stabilisation and gauge couplings at one-loop

    Energy Technology Data Exchange (ETDEWEB)

    Honecker, Gabriele; Koltermann, Isabel [PRISMA Cluster of Excellence, MITP & Institut für Physik (WA THEP),Johannes Gutenberg-Universität,Staudingerweg 9, 55128 Mainz (Germany); Staessens, Wieland [Instituto de Física Teórica UAM-CSIC, Universidad Autónoma de Madrid Cantoblanco,Calle de Nicolás Cabrera 13-15, 28049 Madrid (Spain); Departamento de Física Teórica, Universidad Autónoma de Madrid Cantoblanco,Calle de Nicolás Cabrera 13-15, 28049 Madrid (Spain)

    2017-04-05

    We investigate deformations of ℤ{sub 2} orbifold singularities on the toroidal orbifold T{sup 6}/(ℤ{sub 2}×ℤ{sub 6}) with discrete torsion in the framework of Type IIA orientifold model building with intersecting D6-branes wrapping special Lagrangian cycles. To this aim, we employ the hypersurface formalism developed previously for the orbifold T{sup 6}/(ℤ{sub 2}×ℤ{sub 2}) with discrete torsion and adapt it to the (ℤ{sub 2}×ℤ{sub 6}×ΩR) point group by modding out the remaining ℤ{sub 3} subsymmetry and the orientifold projection ΩR. We first study the local behaviour of the ℤ{sub 3}×ΩR invariant deformation orbits under non-zero deformation and then develop methods to assess the deformation effects on the fractional three-cycle volumes globally. We confirm that D6-branes supporting USp(2N) or SO(2N) gauge groups do not constrain any deformation, while deformation parameters associated to cycles wrapped by D6-branes with U(N) gauge groups are constrained by D-term supersymmetry breaking. These features are exposed in global prototype MSSM, Left-Right symmetric and Pati-Salam models first constructed in (DOI: 10.1016/j.nuclphysb.2015.10.009; 10.1002/prop.201400066), for which we here count the number of stabilised moduli and study flat directions changing the values of some gauge couplings. Finally, we confront the behaviour of tree-level gauge couplings under non-vanishing deformations along flat directions with the one-loop gauge threshold corrections at the orbifold point and discuss phenomenological implications, in particular on possible LARGE volume scenarios and the corresponding value of the string scale M{sub string}, for the same global D6-brane models.

  1. A flux-scaling scenario for high-scale moduli stabilization in string theory

    Directory of Open Access Journals (Sweden)

    Ralph Blumenhagen

    2015-08-01

    Full Text Available Tree-level moduli stabilization via geometric and non-geometric fluxes in type IIB orientifolds on Calabi–Yau manifolds is investigated. The focus is on stable non-supersymmetric minima, where all moduli are fixed except for some massless axions. The scenario includes the purely axionic orientifold-odd moduli. A set of vacua allowing for parametric control over the moduli vacuum expectation values and their masses is presented, featuring a specific scaling with the fluxes. Uplift mechanisms and supersymmetry breaking soft masses on MSSM-like D7-branes are discussed as well. This scenario provides a complete effective framework for realizing the idea of F-term axion monodromy inflation in string theory. It is argued that, with all masses close to the Planck and GUT scales, one is confronted with working at the threshold of controlling all mass hierarchies.

  2. Size-dependent elastic moduli and vibrational properties of fivefold twinned copper nanowires

    Science.gov (United States)

    Zheng, Y. G.; Zhao, Y. T.; Ye, H. F.; Zhang, H. W.

    2014-08-01

    Based on atomistic simulations, the elastic moduli and vibration behaviors of fivefold twinned copper nanowires are investigated in this paper. Simulation results show that the elastic (i.e., Young’s and shear) moduli exhibit size dependence due to the surface effect. The effective Young’s modulus is found to decrease slightly whereas the effective shear modulus increases slightly with the increase in the wire radius. Both moduli tend to approach certain values at a larger radius and can be suitably described by core-shell composite structure models. Furthermore, we show by comparing simulation results and continuum predictions that, provided the effective Young’s and shear moduli are used, classic elastic theory can be applied to describe the small-amplitude vibration of fivefold twinned copper nanowires. Moreover, for the transverse vibration, the Timoshenko beam model is more suitable because shear deformation becomes apparent.

  3. Size-dependent elastic moduli and vibrational properties of fivefold twinned copper nanowires

    International Nuclear Information System (INIS)

    Zheng, Y G; Zhao, Y T; Ye, H F; Zhang, H W

    2014-01-01

    Based on atomistic simulations, the elastic moduli and vibration behaviors of fivefold twinned copper nanowires are investigated in this paper. Simulation results show that the elastic (i.e., Young’s and shear) moduli exhibit size dependence due to the surface effect. The effective Young’s modulus is found to decrease slightly whereas the effective shear modulus increases slightly with the increase in the wire radius. Both moduli tend to approach certain values at a larger radius and can be suitably described by core-shell composite structure models. Furthermore, we show by comparing simulation results and continuum predictions that, provided the effective Young’s and shear moduli are used, classic elastic theory can be applied to describe the small-amplitude vibration of fivefold twinned copper nanowires. Moreover, for the transverse vibration, the Timoshenko beam model is more suitable because shear deformation becomes apparent. (paper)

  4. An Efficient and Accurate Genetic Algorithm for Backcalculation of Flexible Pavement Layer Moduli : Executive Summary Report

    Science.gov (United States)

    2012-12-01

    Backcalculation of pavement moduli has been an intensively researched subject for more than four decades. Despite the existence of many backcalculation programs employing different backcalculation procedures and algorithms, accurate inverse of the la...

  5. Moduli of mathematical instanton vector bundles with odd c2 on projective space

    International Nuclear Information System (INIS)

    Tikhomirov, Aleksandr S

    2012-01-01

    We study the moduli space I n of mathematical instanton vector bundles of rank 2 with second Chern class n≥1 on the projective space P 3 , and prove the irreducibility of I n for arbitrary odd n≥1.

  6. Symplectic geometry on moduli spaces of holomorphic bundles over complex surfaces

    OpenAIRE

    Khesin, Boris; Rosly, Alexei

    2000-01-01

    We give a comparative description of the Poisson structures on the moduli spaces of flat connections on real surfaces and holomorphic Poisson structures on the moduli spaces of holomorphic bundles on complex surfaces. The symplectic leaves of the latter are classified by restrictions of the bundles to certain divisors. This can be regarded as fixing a "complex analogue of the holonomy" of a connection along a "complex analogue of the boundary" in analogy with the real case.

  7. Extrapolation of bulk rock elastic moduli of different rock types to high pressure conditions and comparison with texture-derived elastic moduli

    Science.gov (United States)

    Ullemeyer, Klaus; Lokajíček, Tomás; Vasin, Roman N.; Keppler, Ruth; Behrmann, Jan H.

    2018-02-01

    In this study elastic moduli of three different rock types of simple (calcite marble) and more complex (amphibolite, micaschist) mineralogical compositions were determined by modeling of elastic moduli using texture (crystallographic preferred orientation; CPO) data, experimental investigation and extrapolation. 3D models were calculated using single crystal elastic moduli, and CPO measured using time-of-flight neutron diffraction at the SKAT diffractometer in Dubna (Russia) and subsequently analyzed using Rietveld Texture Analysis. To define extrinsic factors influencing elastic behaviour, P-wave and S-wave velocity anisotropies were experimentally determined at 200, 400 and 600 MPa confining pressure. Functions describing variations of the elastic moduli with confining pressure were then used to predict elastic properties at 1000 MPa, revealing anisotropies in a supposedly crack-free medium. In the calcite marble elastic anisotropy is dominated by the CPO. Velocities continuously increase, while anisotropies decrease from measured, over extrapolated to CPO derived data. Differences in velocity patterns with sample orientation suggest that the foliation forms an important mechanical anisotropy. The amphibolite sample shows similar magnitudes of extrapolated and CPO derived velocities, however the pattern of CPO derived velocity is closer to that measured at 200 MPa. Anisotropy decreases from the extrapolated to the CPO derived data. In the micaschist, velocities are higher and anisotropies are lower in the extrapolated data, in comparison to the data from measurements at lower pressures. Generally our results show that predictions for the elastic behavior of rocks at great depths are possible based on experimental data and those computed from CPO. The elastic properties of the lower crust can, thus, be characterized with an improved degree of confidence using extrapolations. Anisotropically distributed spherical micro-pores are likely to be preserved, affecting

  8. Lectures on moduli of principal G-bundles over algebraic curves

    International Nuclear Information System (INIS)

    Sorger, C.

    2000-01-01

    These notes are supposed to be an introduction to the moduli of G-bundles on curves. Therefore I will lay stress on ideas in order to make these notes more readable. In the last years the moduli spaces of G-bundles over algebraic curves have attracted some attention from various subjects like from conformal field theory or Beilinson and Drinfeld's geometric Langlands program. In both subjects it turned out that the 'stacky' point of view is more convenient and as the basic motivation of these notes is to introduce to the latter subject our moduli spaces will be moduli stacks (and not coarse moduli spaces). As people may feel uncomfortable with stacks I have included a small introduction to them. Actually there is a forthcoming book of Laumon and Moret-Bailly based on their preprint and my introduction merely does the step -1, i.e. explains why we are forced to use them here and recalls the basic results I need later. So here is the plan of the lectures: after some generalities on G-bundles, I will classify them topologically. Actually the proof is more interesting than the result as it will give a flavor of the basic theorem on G-bundles which describes the moduli stack as a double quotient of loop-groups. This 'uniformization theorem', which goes back to A. Weil as a bijection on sets, will be proved in the section following the topological classification. Then I will introduce two line bundles on the moduli stack: the determinant and the paffian bundle. The first one can be used to describe the canonical bundle on the moduli stack and the second to define a square-root of it. Unless G is simply connected the square root depends on the choice of a theta-characteristic. This square root plays an important role in the geometric Langlands program. Actually, in order to get global differential operators on the moduli stack one has to consider twisted differential operators with values in these square-roots. The rest of the lectures will be dedicated to describe the

  9. Moduli Dark Matter and the Search for Its Decay Line using Suzaku X-Ray Telescope

    Science.gov (United States)

    Kusenko, Alexander; Loewenstein, Michael; Yanagida, Tsutomu T.

    2013-01-01

    Light scalar fields called moduli arise from a variety of different models involving supersymmetry and/or string theory; thus their existence is a generic prediction of leading theories for physics beyond the standard model. They also present a formidable, long-standing problem for cosmology. We argue that an anthropic solution to the moduli problem exists in the case of small moduli masses and that it automatically leads to dark matter in the form of moduli. The recent discovery of the 125 GeV Higgs boson implies a lower bound on the moduli mass of about a keV. This form of dark matter is consistent with the observed properties of structure formation, and it is amenable to detection with the help of x-ray telescopes. We present the results of a search for such dark matter particles using spectra extracted from the first deep x-ray observations of the Draco and Ursa Minor dwarf spheroidal galaxies, which are darkmatter- dominated systems with extreme mass-to-light ratios and low intrinsic backgrounds. No emission line is positively detected, and we set new constraints on the relevant new physics.

  10. The moduli space of N=1 superspheres with tubes and the sewing operation

    CERN Document Server

    Barron, Katrina

    2003-01-01

    Within the framework of complex supergeometry and motivated by two-dimensional genus-zero holomorphic N=1 superconformal field theory, we define the moduli space of N=1 genus-zero super-Riemann surfaces with oriented and ordered half-infinite tubes, modulo superconformal equivalence. We define a sewing operation on this moduli space which gives rise to the sewing equation and normalization and boundary conditions. To solve this equation, we develop a formal theory of infinitesimal N=1 superconformal transformations based on a representation of the N=1 Neveu-Schwarz algebra in terms of superderivations. We solve a formal version of the sewing equation by proving an identity for certain exponentials of superderivations involving infinitely many formal variables. We use these formal results to give a reformulation of the moduli space, a more detailed description of the sewing operation, and an explicit formula for obtaining a canonical supersphere with tubes from the sewing together of two canonical superspheres...

  11. The information metric on the moduli space of instantons with global symmetries

    Directory of Open Access Journals (Sweden)

    Emanuel Malek

    2016-02-01

    Full Text Available In this note we revisit Hitchin's prescription [1] of the Fisher metric as a natural measure on the moduli space of instantons that encodes the space–time symmetries of a classical field theory. Motivated by the idea of the moduli space of supersymmetric instantons as an emergent space in the sense of the gauge/gravity duality, we extend the prescription to encode also global symmetries of the underlying theory. We exemplify our construction with the instanton solution of the CPN sigma model on R2.

  12. The Picard group of the moduli space of r-Spin Riemann surfaces

    DEFF Research Database (Denmark)

    Randal-Williams, Oscar

    2012-01-01

    An r-Spin Riemann surface is a Riemann surface equipped with a choice of rth root of the (co)tangent bundle. We give a careful construction of the moduli space (orbifold) of r-Spin Riemann surfaces, and explain how to establish a Madsen–Weiss theorem for it. This allows us to prove the “Mumford...... conjecture” for these moduli spaces, but more interestingly allows us to compute their algebraic Picard groups (for g≥10, or g≥9 in the 2-Spin case). We give a complete description of these Picard groups, in terms of explicitly constructed line bundles....

  13. Dynamic Moduli for the Phase I System Calculated from the 1977 and 1978 Dresser Atlas

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, Christopher F. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    1981-09-29

    The 1977 and 1978 Dresser Atlas acoustic experiments provided a good measure of the P-wave velocity in the Phase 1 system (Fehler, 1981). However, not enough good S-wave arrivals were present in any step to allow Fehler to calculate S-wave velocities using a velocity hyperbola. This is unfortunate because I need the S-wave velocity to calculate dynamic moduli from the seismic velocities. In this memo I describe a method for calculating the S-wave velocity without making a velocity hyperbola and I calculate S-wave velocities and dynamic moduli for the Phase 1 system in 1978.

  14. The geometry of the light-cone cell decomposition of moduli space

    Energy Technology Data Exchange (ETDEWEB)

    Garner, David, E-mail: d.p.r.garner@qmul.ac.uk; Ramgoolam, Sanjaye, E-mail: s.ramgoolam@qmul.ac.uk [Centre for Research in String Theory, School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom)

    2015-11-15

    The moduli space of Riemann surfaces with at least two punctures can be decomposed into a cell complex by using a particular family of ribbon graphs called Nakamura graphs. We distinguish the moduli space with all punctures labelled from that with a single labelled puncture. In both cases, we describe a cell decomposition where the cells are parametrised by graphs or equivalence classes of finite sequences (tuples) of permutations. Each cell is a convex polytope defined by a system of linear equations and inequalities relating light-cone string parameters, quotiented by the automorphism group of the graph. We give explicit examples of the cell decomposition at low genus with few punctures.

  15. Canonical generators of the cohomology of moduli of parabolic bundles on curves

    International Nuclear Information System (INIS)

    Biswas, I.; Raghavendra, N.

    1994-11-01

    We determine generators of the rational cohomology algebras of moduli spaces of parabolic vector bundles on a curve, under some 'primality' conditions on the parabolic datum. These generators are canonical in a precise sense. Our results are new even for usual vector bundles (i.e., vector bundles without parabolic structure) whose rank is greater than 2 and is coprime to the degree; in this case, they are generalizations of a theorem of Newstead on the moduli of vector bundles of rank 2 and odd degree. (author). 11 refs

  16. Poincarщ polynomial of the moduli spaces of parabolic bundles

    Indian Academy of Sciences (India)

    И the set of isomorphism classes of quasi-parabolic vector bundles with data R, and determinant v. ..... The result is first proved over an algebraically closed field, and then Galois descent is applied (using the .... The theorem of Seshadri implies that the topological type of these moduli spaces depends only on the genus g,.

  17. The Euler characteristic of local systems on the moduli of genus 3 hyperelliptic curves.

    NARCIS (Netherlands)

    Bini, G.; van der Geer, G.B.M.

    2005-01-01

    Abstract: For a partition of non-negative integers, we calculate the Euler characteristic of the local system on the moduli space of genus 3 hyperelliptic curves using a suitable stratification. For some cases of low degree, we make a guess for the motivic Euler characteristic of V using counting

  18. On rationality of moduli spaces of vector bundles on real Hirzebruch ...

    Indian Academy of Sciences (India)

    (Math. Sci.) Vol. 123, No. 2, May 2013, pp. 213–223. c Indian Academy of Sciences. On rationality of moduli spaces of vector bundles on real Hirzebruch surfaces. INDRANIL BISWAS1 and RONNIE SEBASTIAN2. 1School of Mathematics, Tata Institute of Fundamental Research,. Homi Bhabha Road, Mumbai 400 005, India.

  19. Stability of Picard bundle over moduli space of stable vector bundles ...

    Indian Academy of Sciences (India)

    Springer Verlag Heidelberg #4 2048 1996 Dec 15 10:16:45

    E-mail: indranil@math.tifr.res.in; tomas@math.tifr.res.in. MS received 14 September 2000. Abstract. Answering a question of [BV] it is proved that the Picard bundle on the moduli space of stable vector bundles of rank two, on a Riemann surface of genus at least three, with fixed determinant of odd degree is stable. Keywords ...

  20. Hurwitz numbers, moduli of curves, topological recursion, Givental's theory and their relations

    NARCIS (Netherlands)

    Spitz, L.

    2014-01-01

    The study of curves is an important area of research in algebraic geometry and mathematical physics. In my thesis I study so-called moduli spaces of curves; these are spaces that parametrize all curves with some specified properties. In particular, I study maps from curves to other spaces, recursive

  1. Determination of static moduli in fractured rocks by T-matrix model

    Czech Academy of Sciences Publication Activity Database

    Chalupa, F.; Vilhelm, J.; Petružálek, Matěj; Bukovská, Z.

    2017-01-01

    Roč. 22, č. 1 (2017), s. 22-31 ISSN 1335-1788 Institutional support: RVO:67985831 Keywords : fractured rocks * dynamic and static moduli * T-matrix model * elastic wave velocity * well logging Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 0.769, year: 2016 http://actamont.tuke.sk/pdf/2017/n1/3chalupa.pdf

  2. A family of metrics on the moduli space of CP2 instantons

    International Nuclear Information System (INIS)

    Habermann, L.

    1992-01-01

    A family of Riemannian metrics on the moduli space of irreducible self-dual connections of instanton number k=1 over CP 2 is considered. We find explicit formulas for these metrics and deduce conclusions concerning the geometry of the instant space. (orig.)

  3. Hilbert Series for Moduli Spaces of Instantons on C^2/Z_n

    CERN Document Server

    Dey, Anindya; Mekareeya, Noppadol; Rodríguez-Gómez, Diego; Seong, Rak-Kyeong

    2014-01-01

    We study chiral gauge-invariant operators on moduli spaces of G instantons for any classical group G on A-type ALE spaces using Hilbert Series (HS). Moduli spaces of instantons on an ALE space can be realized as Higgs branches of certain quiver gauge theories which appear as world-volume theories on Dp branes in a Dp-D(p+4) system with the D(p+4) branes (with or without O(p+4) planes) wrapping the ALE space. We study in detail a list of quiver gauge theories which are related to G-instantons of arbitrary ranks and instanton numbers on a generic A_{n-1} ALE space and discuss the corresponding brane configurations. For a large class of theories, we explicitly compute the Higgs branch HS which reveals various algebraic/geometric aspects of the moduli space such as the dimension of the space, generators of the moduli space and relations connecting them. In a large number of examples involving lower rank instantons, we demonstrate that HS for equivalent instantons of isomorphic gauge groups but very different quiv...

  4. Stability of Picard bundle over moduli space of stable vector bundles ...

    Indian Academy of Sciences (India)

    Springer Verlag Heidelberg #4 2048 1996 Dec 15 10:16:45

    Stability of Picard bundle over moduli space of stable vector bundles of rank two over a curve. INDRANIL BISWAS and TOM ´AS L G ´OMEZ. School of Mathematics, Tata Institute of Fundamental Research, Homi Bhabha Road,. Mumbai 400 005, India. E-mail: indranil@math.tifr.res.in; tomas@math.tifr.res.in. MS received 14 ...

  5. Euler characteristics of moduli spaces of torsion free sheaves on toric surfaces

    NARCIS (Netherlands)

    Kool, M.

    2015-01-01

    Given a smooth toric variety X, the action of the torus T lifts to the moduli space M of stable sheaves on X. Using the pioneering work of Klyacho, a fairly explicit combinatorial description of the fixed point locus MT can be given (as shown by earlier work of the author). In this paper, we apply

  6. Moser Vector Fields and Geometry of the Mabuchi Moduli Space of Kähler Metrics

    Directory of Open Access Journals (Sweden)

    Daniel Guan

    2014-01-01

    Full Text Available There is a natural Moser type transformation along any curve in the moduli spaces of Kähler metrics. In this paper we apply this transformation to give an explicit construction of the parallel transformation along a curve in the Mabuchi moduli space of Kähler metrics. This is crucial in the proof of the equivalence between the existence of the Kähler metrics with constant scalar curvature and the geodesic stability for the type II compact almost homogeneous manifolds of cohomogeneity one mentioned in (Guan 2013. We also explain a new description of the geodesics and prove a curvature property of the moduli space, called curvature symmetric, which makes it similar to some special symmetric spaces with nonpositive curvatures, although the spaces are usually not complete. Finally, we generalize our geodesic stability conjectures in (Guan 2003 and give several results on the Lie algebra structures related to the parallel transformations. In the last section, we generalize the Futaki obstruction of the Kähler-Einstein metrics to the parallel vector fields of the invariant Mabuchi moduli space. We call the related stability the parallel stability. This includes the toric and cohomogeneity one cases as well as the spherical manifolds.

  7. The determinant bundle on the moduli space of stable triples over a ...

    Indian Academy of Sciences (India)

    The curvature of the Chern connection of this holomorphic Hermitian line bundle is computed. The curvature is shown to coincide with a constant scalar multiple of the natural Kähler form on the moduli space. The construction is based on a result of Quillen on the determinant line bundle over the space of Dolbeault ...

  8. Mirror symmetry and the moduli space for generic hypersurfaces in toric varieties

    CERN Document Server

    Berglund, P; Klemm, A D

    1995-01-01

    The moduli dependence of (2,2) superstring compactifications based on Calabi--Yau hypersurfaces in weighted projective space has so far only been investigated for Fermat-type polynomial constraints. These correspond to Landau-Ginzburg orbifolds with c=9 whose potential is a sum of A-type singularities. Here we consider the generalization to arbitrary quasi-homogeneous singularities at c=9. We use mirror symmetry to derive the dependence of the models on the complexified K\\"ahler moduli and check the expansions of some topological correlation functions against explicit genus zero and genus one instanton calculations. As an important application we give examples of how non-algebraic (``twisted'') deformations can be mapped to algebraic ones, hence allowing us to study the full moduli space. We also study how moduli spaces can be nested in each other, thus enabling a (singular) transition from one theory to another. Following the recent work of Greene, Morrison and Strominger we show that this corresponds to bla...

  9. Poincaré polynomial of the moduli spaces of parabolic bundles

    Indian Academy of Sciences (India)

    In this paper we use Weil conjectures (Deligne's theorem) to calculate the Betti numbers of the moduli spaces of semi-stable parabolic bundles on a curve. The quasi parabolic analogue of the Siegel formula, together with the method of Harder-Narasimhan filtration gives us a recursive formula for the Poincaré polynomials ...

  10. The determinant bundle on the moduli space of stable triples over a ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Abstract. We construct a holomorphic Hermitian line bundle over the moduli space of stable triples of the form (E1,E2,φ), where E1 and E2 are holomorphic vector bundles over a fixed compact Riemann surface X, and φ : E2 −→ E1 is a holomorphic vector bundle homomorphism. The curvature of the Chern connection of ...

  11. TOPICAL REVIEW: Solitons in the Higgs phase: the moduli matrix approach

    Science.gov (United States)

    Eto, Minoru; Isozumi, Youichi; Nitta, Muneto; Ohashi, Keisuke; Sakai, Norisuke

    2006-06-01

    We review our recent work on solitons in the Higgs phase. We use U(NC) gauge theory with NF Higgs scalar fields in the fundamental representation, which can be extended to possess eight supercharges. We propose the moduli matrix as a fundamental tool to exhaust all BPS solutions, and to characterize all possible moduli parameters. Moduli spaces of domain walls (kinks) and vortices, which are the only elementary solitons in the Higgs phase, are found in terms of the moduli matrix. Stable monopoles and instantons can exist in the Higgs phase if they are attached by vortices to form composite solitons. The moduli spaces of these composite solitons are also worked out in terms of the moduli matrix. Webs of walls can also be formed with characteristic difference between Abelian and non-Abelian gauge theories. Instanton-vortex systems, monopole-vortex-wall systems, and webs of walls in Abelian gauge theories are found to admit negative energy objects with the instanton charge (called intersectons), the monopole charge (called boojums) and the Hitchin charge, respectively. We characterize the total moduli space of these elementary as well as composite solitons. In particular the total moduli space of walls is given by the complex Grassmann manifold SU(NF)/[SU(NC) × SU(NF - NC) × U(1)] and is decomposed into various topological sectors corresponding to boundary condition specified by particular vacua. The moduli space of k vortices is also completely determined and is reformulated as the half ADHM construction. Effective Lagrangians are constructed on walls and vortices in a compact form. We also present several new results on interactions of various solitons, such as monopoles, vortices and walls. Review parts contain our works on domain walls (Isozumi Y et al 2004 Phys. Rev. Lett. 93 161601 (Preprint hep-th/0404198), Isozumi Y et al 2004 Phys. Rev. D 70 125014 (Preprint hep-th/0405194), Eto M et al 2005 Phys. Rev. D 71 125006 (Preprint hep-th/0412024), Eto M et al 2005

  12. Quantum triangulations moduli space, quantum computing, non-linear sigma models and Ricci flow

    CERN Document Server

    Carfora, Mauro

    2017-01-01

    This book discusses key conceptual aspects and explores the connection between triangulated manifolds and quantum physics, using a set of case studies ranging from moduli space theory to quantum computing to provide an accessible introduction to this topic. Research on polyhedral manifolds often reveals unexpected connections between very distinct aspects of mathematics and physics. In particular, triangulated manifolds play an important role in settings such as Riemann moduli space theory, strings and quantum gravity, topological quantum field theory, condensed matter physics, critical phenomena and complex systems. Not only do they provide a natural discrete analogue to the smooth manifolds on which physical theories are typically formulated, but their appearance is also often a consequence of an underlying structure that naturally calls into play non-trivial aspects of representation theory, complex analysis and topology in a way that makes the basic geometric structures of the physical interactions involv...

  13. Anti-D3 branes and moduli in non-linear supergravity

    Science.gov (United States)

    Garcia del Moral, Maria P.; Parameswaran, Susha; Quiroz, Norma; Zavala, Ivonne

    2017-10-01

    Anti-D3 branes and non-perturbative effects in flux compactifications spontaneously break supersymmetry and stabilise moduli in a metastable de Sitter vacua. The low energy 4D effective field theory description for such models would be a supergravity theory with non-linearly realised supersymmetry. Guided by string theory modular symmetry, we compute this non-linear supergravity theory, including dependence on all bulk moduli. Using either a constrained chiral superfield or a constrained vector field, the uplifting contribution to the scalar potential from the anti-D3 brane can be parameterised either as an F-term or Fayet-Iliopoulos D-term. Using again the modular symmetry, we show that 4D non-linear supergravities that descend from string theory have an enhanced protection from quantum corrections by non-renormalisation theorems. The superpotential giving rise to metastable de Sitter vacua is robust against perturbative string-loop and α' corrections.

  14. D3/D7 branes at singularities: constraints from global embedding and moduli stabilisation

    Science.gov (United States)

    Cicoli, M.; Krippendorf, S.; Mayrhofer, C.; Quevedo, F.; Valandro, R.

    2013-07-01

    In the framework of type IIB string compactifications on Calabi-Yau orien-tifolds we describe how to construct consistent global embeddings of models with fractional D3-branes and connected `flavour' D7-branes at del Pezzo singularities with moduli stabilisation. Our results are applied to build an explicit compact example with a left-right symmetric model at a dP0 singularity which features three families of chiral matter and gauge coupling unification at the intermediate scale. We show how to stabilise the moduli obtaining a controlled de Sitter minimum and spontaneous supersymmetry breaking. We find an interesting non-trivial dynamical relation between the requirement of TeV-scale soft terms and the correct phenomenological values of the unified gauge coupling and unification scale.

  15. Moduli backreaction and supersymmetry breaking in string-inspired inflation models

    International Nuclear Information System (INIS)

    Dudas, Emilian; Wieck, Clemens

    2015-06-01

    We emphasize the importance of effects from heavy fields on supergravity models of inflation. We study, in particular, the backreaction of stabilizer fields and geometric moduli in the presence of supersymmetry breaking. Many effects do not decouple even if those fields are much heavier than the inflaton field. We apply our results to successful models of Starobinsky-like inflation and natural inflation. In most scenarios producing a plateau potential it proves difficult to retain the flatness of the potential after backreactions are taken into account. Some of them are incompatible with non-perturbative moduli stabilization. In natural inflation there exist a number of models which are not constrained by backreactions at all. In those cases the correction terms from heavy fields have the same inflaton-dependence as the uncorrected potential, so that inflation may be possible even for very large gravitino masses.

  16. Topological sectors and measures on moduli space in quantum Yang-Mills on a Riemann surface

    Science.gov (United States)

    Fine, Dana Stanley

    1996-03-01

    Previous path integral treatments of Yang-Mills on a Riemann surface automatically sum over principal fiber bundles of all possible topological types in computing quantum expectations. This paper extends the path integral formulation to treat separately each topological sector. The formulation is sufficiently explicit to calculate Wilson line expectations exactly. Further, it suggests two new measures on the moduli space of flat connections, one of which proves to agree with the small-volume limit of the Yang-Mills measure.

  17. Experimental and theoretical investigation of the elastic moduli of silicate glasses and crystals

    Science.gov (United States)

    Philipps, Katharina; Stoffel, Ralf Peter; Dronskowski, Richard; Conradt, Reinhard

    2017-02-01

    A combined quantum-mechanical and thermodynamic approach to the mechanical properties of multicomponent silicate glasses is presented. Quantum chemical calculations based on density-functional theory (DFT) on various silicate systems were performed to explore the crystalline polymorphs existing for a given chemical composition. These calculations reproduced the properties of known polymorphs even in systems with extensive polymorphism, like MgSiO3. Properties resting on the atomic and electronic structure, i.e., molar volumes (densities) and bulk moduli were predicted correctly. The theoretical data (molar equilibrium volumes, bulk moduli) were then used to complement the available experimental data. In a phenomenological evaluation, experimental data of bulk moduli, a macroscopic property resting on phononic structure, were found to linearly scale with the ratios of atomic space demand to actual molar volume in a universal way. Silicates ranging from high-pressure polymorphs to glasses were represented by a single master line. This suggests that above the Debye limit (in practice: above room temperature), the elastic waves probe the short range order coordination polyhedra and their next-neighbor linkage only, while the presence or absence of an extended translational symmetry is irrelevant. As a result, glasses can be treated - with respect to the properties investigated - as commensurable members of polymorphic series. Binary glasses fit the very same line as their one-component end-members, again both in the crystalline and glassy state. Finally, it is shown that the macroscopic properties of multicomponent glasses also are linear superpositions of the properties of their constitutional phases (as determined from phase diagrams or by thermochemical calculations) taken in their respective glassy states. This is verified experimentally for heat capacities and Young’s moduli of industrial glass compositions. It can be concluded, that the combined quantum

  18. Nondestructive Evaluation of Young's Moduli of Full-Size wood Laminated Composite Poles

    Science.gov (United States)

    Cheng Piao; Todd F. Shube; Chung Y. Hse; R.C. Tang

    2004-01-01

    An exploratory study was conducted to evaluate the Young's moduli of wood laminated composite poles (LCP) by using a free transverse vibration method. Full-size LCP, 6.1 m long and 10.2 cm in diameter, were lab-fabricated with 9 and/or 12 southern yellow pine [SYP] strips of thickness, 1.9 cm, 2.9 cm and 3.8 cm. The frequency of free transverse vibration in a LCP...

  19. Simultaneous moduli measurement of elastic materials at elevated temperatures using an ultrasonic waveguide method

    Science.gov (United States)

    Periyannan, Suresh; Balasubramaniam, Krishnan

    2015-11-01

    A novel technique for simultaneously measuring the moduli of elastic isotropic material, as a function of temperature, using two ultrasonic guided wave modes that are co-generated using a single probe is presented here. This technique can be used for simultaneously measuring Young's modulus (E) and shear modulus (G) of different materials over a wide range of temperatures (35 °C-1200 °C). The specimens used in the experiments have special embodiments (for instance, a bend) at one end of the waveguide and an ultrasonic guided wave generator/detector (transducer) at the other end for obtaining reflected signals in a pulse-echo mode. The orientation of the transducer can be used for simultaneously generating/receiving the L(0,1) and/or T(0,1) using a single transducer in a waveguide on one end. The far end of the waveguides with the embodiment is kept inside a heating device such as a temperature-controlled furnace. The time of flight difference, as a function of uniform temperature distribution region (horizontal portion) of bend waveguides was measured and used to determine the material properties. Several materials were tested and the comparison between values reported in the literature and measured values were found to be in agreement, for both elastic moduli (E and G) measurements, as a function of temperature. This technique provides significant reduction in time and effort over conventional means of measurement of temperature dependence of elastic moduli.

  20. Correlation between longitudinal, circumferential, and radial moduli in cortical bone: effect of mineral content.

    Science.gov (United States)

    Macione, J; Depaula, C A; Guzelsu, N; Kotha, S P

    2010-07-01

    Previous studies indicate that changes in the longitudinal elastic properties of bone due to changes in mineral content are related to the longitudinal strength of bone tissue. Changes in mineral content are expected to affect bone tissue mechanical properties along all directions, albeit to different extents. However, changes in tissue mechanical properties along the different directions are expected to be correlated to one another. In this study, we investigate if radial, circumferential, and longitudinal moduli are related in bone tissue with varying mineral content. Plexiform bovine femoral bone samples were treated in fluoride ion solutions for a period of 3 and 12 days to obtain bones with 20% and 32% lower effective mineral contents. Transmission ultrasound velocities were obtained in the radial, circumferential, and longitudinal axes of bone and combined with measured densities to obtain corresponding tensorial moduli. Results indicate that moduli decreased with fluoride ion treatments and were significantly correlated to one another (r(2) radial vs. longitudinal = 0.80, r(2) circumferential vs. longitudinal = 0.90, r(2) radial vs. circumferential = 0.85). Densities calculated from using ultrasound parameters, acoustic impedance and transmission velocities, were moderately correlated to those measured by the Archimedes principle (r(2)=0.54, p<0.01). These results suggest that radial and circumferential ultrasound measurements could be used to determine the longitudinal properties of bone and that ultrasound may not be able to predict in vitro densities of bones containing unbonded mineral. Published by Elsevier Ltd.

  1. N=2 topological gauge theory, the Euler characteristic of moduli spaces, and the Casson invariant

    International Nuclear Information System (INIS)

    Blau, M.; Thompson, G.

    1991-11-01

    Gauge theory with a topological N=2 symmetry is discussed. This theory captures the de Rahm complex and Riemannian geometry of some underlying moduli space M and the partition function equals the Euler number χ (M) of M. Moduli spaces of instantons and of flat connections in 2 and 3 dimensions are explicitly dealt with. To motivate the constructions the relation between the Mathai-Quillen formalism and supersymmetric quantum mechanics are explained and a new kind of supersymmetric quantum mechanics is introduced, based on the Gauss-Codazzi equations. The gauge theory actions are interpreted from the Atiyah-Jeffrey point of view and related to super-symmetric quantum mechanics on spaces of connections. As a consequence of these considerations the Euler number χ (M) of the moduli space of flat connections as a generalization to arbitrary three-manifolds of the Casson invariant. The possibility of constructing a topological version of the Penner matrix model is also commented. (author). 63 refs

  2. Realistic D-brane models on warped throats: Fluxes, hierarchies and moduli stabilization

    International Nuclear Information System (INIS)

    Cascales, J.F.G.; Garcia del Moral, M.P.; Quevedo, F.; Uranga, A.

    2004-01-01

    We describe the construction of string theory models with semirealistic spectrum in a sector of (anti) D3-branes located at an orbifold singularity at the bottom of a highly warped throat geometry, which is a generalisation of the Klebanov-Strassler deformed conifold. These models realise the Randall-Sundrum proposal to naturally generate the Planck/electroweak hierarchy in a concrete string theory embedding, and yielding interesting chiral open string spectra. We describe examples with Standard Model gauge group (or left-right symmetric extensions) and three families of SM fermions, with correct quantum numbers including hypercharge. The dilaton and complex structure moduli of the geometry are stabilised by the 3-form fluxes required to build the throat. We describe diverse issues concerning the stabilisation of geometric Kahler moduli, like blow-up modes of the orbifold singularities, via D term potentials and gauge theory non-perturbative effects, like gaugino condensation. This local geometry, once embedded in a full compactification, could give rise to models with all moduli stabilised, and with the potential to lead to de Sitter vacua. Issues of gauge unification, proton stability, supersymmetry breaking and Yukawa couplings are also discussed. (author)

  3. Experimentally-based multiscale model of the elastic moduli of bovine trabecular bone and its constituents.

    Science.gov (United States)

    Hamed, Elham; Novitskaya, Ekaterina; Li, Jun; Jasiuk, Iwona; McKittrick, Joanna

    2015-09-01

    The elastic moduli of trabecular bone were modeled using an analytical multiscale approach. Trabecular bone was represented as a porous nanocomposite material with a hierarchical structure spanning from the collagen-mineral level to the trabecular architecture level. In parallel, compression testing was done on bovine femoral trabecular bone samples in two anatomical directions, parallel to the femoral neck axis and perpendicular to it, and the measured elastic moduli were compared with the corresponding theoretical results. To gain insights on the interaction of collagen and minerals at the nanoscale, bone samples were deproteinized or demineralized. After such processing, the treated samples remained as self-standing structures and were tested in compression. Micro-computed tomography was used to characterize the hierarchical structure of these three bone types and to quantify the amount of bone porosity. The obtained experimental data served as inputs to the multiscale model and guided us to represent bone as an interpenetrating composite material. Good agreement was found between the theory and experiments for the elastic moduli of the untreated, deproteinized, and demineralized trabecular bone. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Neutrino masses, Baryon asymmetry, dark matter and the moduli problem - A complete framework

    International Nuclear Information System (INIS)

    Kumar, Piyush

    2009-01-01

    Recent developments in string theory have led to 'realistic' string compactifications which lead to moduli stabilization while generating a hierarchy between the Electroweak and Planck scales at the same time. However, this seems to suggest a rethink of our standard notions of cosmological evolution after the end of inflation and before the beginning of BBN. This epoch is crucial for addressing the issues of neutrino masses, baryon asymmetry, Dark Matter (DM) abundance and the moduli (gravitino) problem. We argue that within classes of realistic string compactifications as defined above, there generically exists a light modulus with a mass comparable to that of the gravitino which is typically much smaller than the Hubble parameter during inflation. Therefore, it is destabilized and generates a large late-time entropy when it decays. Thus, all known elegant mechanisms of generating the baryon asymmetry of the Universe in the literature have to take this fact into account. In this work, we find that it is still possible to naturally generate the observed baryon asymmetry of the Universe as well as light left-handed neutrino masses from a period of Affleck-Dine (AD) leptogenesis shortly after the end of inflation, in classes of realistic string constructions with a minimal extension of the MSSM below the unification scale (consisting only of right-handed neutrinos) and satisfying certain microscopic criteria described in the text. The AD mechanism has already been used to generate the baryon asymmetry in the literature; however in this work we have embedded the above mechanism within a framework well motivated from string theory and have tried to describe the epoch from the end of inflation to the beginning of BBN in a complete and self-consistent manner. The consequences of our analysis are as follows. The lightest left-handed neutrino is required to be virtually massless. The moduli (gravitino) problem can be naturally solved in this framework both within gravity

  5. GUT scale extra dimensions and light moduli in supergravity and cosmology

    International Nuclear Information System (INIS)

    Moeller, Jan

    2010-05-01

    We study the dynamical properties of geometric moduli in five- and six-dimensional supergravity compactified on flat orbifolds, focusing on the impact of the Kaehler potential. In both cases, the Kaehler potential exhibits no-scale structure at tree level. In five dimensions, the volume modulus (radion) can be stabilized by means of perturbative Kaehler corrections. In six dimensions, the same holds for size and shape of the extra dimensions, only if the dilaton can be stabilized in a Minkowski vacuum by nonperturbative effects. We develop a systematic description of almost no-scale models and derive a model independent formula for the radion mass. The radion mass is suppressed compared to the gravitino mass. The supression factor reflects the hierarchy between the Planck and the compactification scale. We analyze a specific example, where the compactification scale is determined by Fayet-Iliopoulos terms of a locally anomalous Abelian gauge group, which are O(M GUT ). In a scenario with gravitino dark matter, this leads to a radion mass of 1-10 MeV. In this mass range, the radion is cosmologically stable and contributes to the dark matter density. Based on galactic gamma ray data, we derive a tight bound on the initial displacement of the field value from its low energy vacuum. We also investigate implications of typical moduli Kaehler potentials on the cosmological evolution of the scalar fields. In particular, we discuss a class of models with steep exponential potentials and non-canonical kinetic terms, motivated by our radion example. We consider the overshooting problem of cosmological moduli dynamics, and the possibility of slow-roll solutions despite the steepness of the scalar potential. (orig.)

  6. GUT scale extra dimensions and light moduli in supergravity and cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, Jan

    2010-05-15

    We study the dynamical properties of geometric moduli in five- and six-dimensional supergravity compactified on flat orbifolds, focusing on the impact of the Kaehler potential. In both cases, the Kaehler potential exhibits no-scale structure at tree level. In five dimensions, the volume modulus (radion) can be stabilized by means of perturbative Kaehler corrections. In six dimensions, the same holds for size and shape of the extra dimensions, only if the dilaton can be stabilized in a Minkowski vacuum by nonperturbative effects. We develop a systematic description of almost no-scale models and derive a model independent formula for the radion mass. The radion mass is suppressed compared to the gravitino mass. The supression factor reflects the hierarchy between the Planck and the compactification scale. We analyze a specific example, where the compactification scale is determined by Fayet-Iliopoulos terms of a locally anomalous Abelian gauge group, which are O(M{sub GUT}). In a scenario with gravitino dark matter, this leads to a radion mass of 1-10 MeV. In this mass range, the radion is cosmologically stable and contributes to the dark matter density. Based on galactic gamma ray data, we derive a tight bound on the initial displacement of the field value from its low energy vacuum. We also investigate implications of typical moduli Kaehler potentials on the cosmological evolution of the scalar fields. In particular, we discuss a class of models with steep exponential potentials and non-canonical kinetic terms, motivated by our radion example. We consider the overshooting problem of cosmological moduli dynamics, and the possibility of slow-roll solutions despite the steepness of the scalar potential. (orig.)

  7. In vitro behaviors of rat mesenchymal stem cells on bacterial celluloses with different moduli

    Energy Technology Data Exchange (ETDEWEB)

    Taokaew, Siriporn [Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330 (Thailand); Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325-3906 (United States); Phisalaphong, Muenduen [Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330 (Thailand); Zhang Newby, Bi-min, E-mail: bimin@uakron.edu [Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325-3906 (United States)

    2014-05-01

    Compressive moduli of bacteria-synthesized cellulose (BC) were altered by two drying techniques: ambient-air drying and freeze drying. While no significant differences in dry weight were found, their cross-sectional structures and thickness varied greatly. Freeze dried BCs had loose cross-sectional structures and a thickness of ∼ 4.7 mm, whereas air dried BCs had more compacted cross-sectional structures and a thickness of ∼ 0.1 mm. The compressive moduli of the rehydrated freeze dried and rehydrated air dried BCs were measured to be 21.06 ± 0.22 kPa and 90.09 ± 21.07 kPa, respectively. When rat mesenchymal stem cells (rMSCs) were seeded on these BCs, they maintained a round morphology in the first 3 days of cultivation. More spread-out morphology and considerable proliferation on freeze dried BCs were observed in 7 days, but not on air-dried BCs. The cells were further grown for 3 weeks in the absence and presence of differentiation agents. Without using any differentiation agents, no detectable differentiation was noticed for rMSCs further cultivated on both types of BC. With differentiation inducing agents, chondrogenic differentiation, visualized by histological staining, was observed in some area of the rehydrated freeze dried BCs; while osteogenic differentiation was noticed on the stiffer rehydrated air dried BCs. - Graphical abstract: In the presence of induction agents, rat mesenchymal stem cells (rMSCs) preferentially differentiated into osteocytes on stiffer air dried BC films. - Highlights: • Bacterial cellulose (BC) sheets with different moduli generated by drying differently • Air-dried BC exhibited a modulus similar to that of bone. • Freeze-dried BC showed a modulus in the range of that of muscle. • Air-dried BC promoted the differentiation of rMSCs into osteocytes. • Freeze-dried BC promoted the differentiation of rMSCs into chondrocytes.

  8. Quantitative determination of optical trapping strength and viscoelastic moduli inside living cells

    International Nuclear Information System (INIS)

    Mas, Josep; Berg-Sørensen, Kirstine; Richardson, Andrew C; Reihani, S Nader S; Oddershede, Lene B

    2013-01-01

    With the success of in vitro single-molecule force measurements obtained in recent years, the next step is to perform quantitative force measurements inside a living cell. Optical traps have proven excellent tools for manipulation, also in vivo, where they can be essentially non-invasive under correct wavelength and exposure conditions. It is a pre-requisite for in vivo quantitative force measurements that a precise and reliable force calibration of the tweezers is performed. There are well-established calibration protocols in purely viscous environments; however, as the cellular cytoplasm is viscoelastic, it would be incorrect to use a calibration procedure relying on a viscous environment. Here we demonstrate a method to perform a correct force calibration inside a living cell. This method (theoretically proposed in Fischer and Berg-Sørensen (2007 J. Opt. A: Pure Appl. Opt. 9 S239)) takes into account the viscoelastic properties of the cytoplasm and relies on a combination of active and passive recordings of the motion of the cytoplasmic object of interest. The calibration procedure allows us to extract absolute values for the viscoelastic moduli of the living cell cytoplasm as well as the force constant describing the optical trap, thus paving the way for quantitative force measurements inside the living cell. Here, we determine both the spring constant of the optical trap and the elastic contribution from the cytoplasm, influencing the motion of naturally occurring tracer particles. The viscoelastic moduli that we find are of the same order of magnitude as moduli found in other cell types by alternative methods. (paper)

  9. Variational method of determining effective moduli of polycrystals with tetragonal symmetry

    Science.gov (United States)

    Meister, R.; Peselnick, L.

    1966-01-01

    Variational principles have been applied to aggregates of randomly oriented pure-phase polycrystals having tetragonal symmetry. The bounds of the effective elastic moduli obtained in this way show a substantial improvement over the bounds obtained by means of the Voigt and Reuss assumptions. The Hill average is found to be a good approximation in most cases when compared to the bounds found from the variational method. The new bounds reduce in their limits to the Voigt and Reuss values. ?? 1966 The American Institute of Physics.

  10. Variational method of determining effective moduli of polycrystals: (A) hexagonal symmetry, (B) trigonal symmetry

    Science.gov (United States)

    Peselnick, L.; Meister, R.

    1965-01-01

    Variational principles of anisotropic elasticity have been applied to aggregates of randomly oriented pure-phase polycrystals having hexagonal symmetry and trigonal symmetry. The bounds of the effective elastic moduli obtained in this way show a considerable improvement over the bounds obtained by means of the Voigt and Reuss assumptions. The Hill average is found to be in most cases a good approximation when compared to the bounds found from the variational method. The new bounds reduce in their limits to the Voigt and Reuss values. ?? 1965 The American Institute of Physics.

  11. Simultaneous measurement of field dependence of elastic moduli by laser interferometry

    CERN Document Server

    Bayon, A; Salazar, F

    2000-01-01

    A methodology is applied which allows the simultaneous determination of Young's modulus and the shear modulus to evaluate elastic moduli variations with the magnetic field (DELTA E and DELTA G). The method employed is based on the simultaneous detection of the transverse and torsional natural frequencies of a slender magnetic bar located within a solenoid. The resultant vibration is detected via a heterodyne interferometric optical system with a broad bandwidth. The vibration detection and excitation systems do not interact with the sample. The applicability of the method is demonstrated by characterizing 10-mm-diameter nickel bars. The results are compared with those obtained from longitudinal vibrations.

  12. Feeding strategies as revealed by the section moduli of the humerus bones in bipedal theropod dinosaurs

    Science.gov (United States)

    Lee, Scott; Richards, Zachary

    2015-03-01

    The section modulus of a bone is a measure of its ability to resist bending torques. Carnivorous dinosaurs presumably had strong arm bones to hold struggling prey during hunting. Some theropods are believed to have become herbivorous and such animals would not have needed such strong arms. In this work, the section moduli of the humerus bones of bipedal theropod dinosaurs (from Microvenator celer to Tyrannosaurus rex) are studied to determine the maximum bending loads their arms could withstand. The results show that bending strength is not of uniform importance to these magnificent animals. The predatory theropods had strong arms for use in hunting. In contrast, the herbivorous dinosaurs had weaker arms.

  13. Connecting p-gonal loci in the compactification of moduli space

    OpenAIRE

    Costa, Antonio F.; Izquierdo, Milagros; Parlier, Hugo

    2015-01-01

    Consider the moduli space $\\mathcal{M}_{g}$ of Riemann surfaces of genus $g\\geq 2$ and its Deligne-Munford compactification $\\bar{\\mathcal{M}_{g}}$. We are interested in the branch locus ${\\mathcal{B}_{g}}$ for $g>2$, i.e., the subset of $\\mathcal{M}_{g}$ consisting of surfaces with automorphisms. It is well-known that the set of hyperelliptic surfaces (the hyperelliptic locus) is connected in $\\mathcal{M}_{g}$ but the set of (cyclic) trigonal surfaces is not. By contrast, we show that for $g...

  14. Representation of moduli spaces of curves and calculation of extremal polynomials

    International Nuclear Information System (INIS)

    Bogatyrev, A B

    2003-01-01

    The classical Chebyshev and Zolotarev polynomials are the first ranks of the hierarchy of extremal polynomials, which are typical solutions of problems on the conditional minimization of the uniform norm over a space of polynomials. In the general case such polynomials are connected with hyperelliptic curves the genus of which labels the ranks of the hierarchy. Representations of the moduli spaces of such curves are considered in this paper with applications to the calculation of extremal polynomials. Uniformizing curves by special Schottky groups one obtains effectively computable parametric expressions for extremal polynomials in terms of linear series of Poincare

  15. N=2→0 super no-scale models and moduli quantum stability

    Directory of Open Access Journals (Sweden)

    Costas Kounnas

    2017-06-01

    Full Text Available We consider a class of heterotic N=2→0 super no-scale Z2-orbifold models. An appropriate stringy Scherk–Schwarz supersymmetry breaking induces tree level masses to all massless bosons of the twisted hypermultiplets and therefore stabilizes all twisted moduli. At high supersymmetry breaking scale, the tachyons that occur in the N=4→0 parent theories are projected out, and no Hagedorn-like instability takes place in the N=2→0 models (for small enough marginal deformations. At low supersymmetry breaking scale, the stability of the untwisted moduli is studied at the quantum level by taking into account both untwisted and twisted contributions to the 1-loop effective potential. The latter depends on the specific branch of the gauge theory along which the background can be deformed. We derive its expression in terms of all classical marginal deformations in the pure Coulomb phase, and in some mixed Coulomb/Higgs phases. In this class of models, the super no-scale condition requires having at the massless level equal numbers of untwisted bosonic and twisted fermionic degrees of freedom. Finally, we show that N=1→0 super no-scale models are obtained by implementing a second Z2 orbifold twist on N=2→0 super no-scale Z2-orbifold models.

  16. Moduli dynamics as a predictive tool for thermal maximally supersymmetric Yang-Mills at large N

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Takeshi [Department of Physics, Shizuoka University,836 Ohya, Suruga-ku, Shizuoka 422-8529 (Japan); Department of Physics and Astronomy, University of Kentucky,Lexington, KY 40506 (United States); Shiba, Shotaro [Maskawa Institute for Science and Culture, Kyoto Sangyo University,Kamigamo-Motoyama, Kita-ku, Kyoto 603-8555 (Japan); Wiseman, Toby [Theoretical Physics Group, Blackett Laboratory, Imperial College,Exhibition Road, London SW7 2AZ (United Kingdom); Withers, Benjamin [Mathematical Sciences and STAG Research Centre, University of Southampton,Highfield, Southampton SO17 1BJ (United Kingdom)

    2015-07-09

    Maximally supersymmetric (p+1)-dimensional Yang-Mills theory at large N and finite temperature, with possibly compact spatial directions, has a rich phase structure. Strongly coupled phases may have holographic descriptions as black branes in various string duality frames, or there may be no gravity dual. In this paper we provide tools in the gauge theory which give a simple and unified picture of the various strongly coupled phases, and transitions between them. Building on our previous work we consider the effective theory describing the moduli of the gauge theory, which can be computed precisely when it is weakly coupled far out on the Coulomb branch. Whilst for perturbation theory naive extrapolation from weak coupling to strong gives little information, for this moduli theory naive extrapolation from its weakly to its strongly coupled regime appears to encode a surprising amount of information about the various strongly coupled phases. We argue it encodes not only the parametric form of thermodynamic quantities for these strongly coupled phases, but also certain transcendental factors with a geometric origin, and allows one to deduce transitions between the phases. We emphasise it also gives predictions for the behaviour of other observables in these phases.

  17. Ridge regression for predicting elastic moduli and hardness of calcium aluminosilicate glasses

    Science.gov (United States)

    Deng, Yifan; Zeng, Huidan; Jiang, Yejia; Chen, Guorong; Chen, Jianding; Sun, Luyi

    2018-03-01

    It is of great significance to design glasses with satisfactory mechanical properties predictively through modeling. Among various modeling methods, data-driven modeling is such a reliable approach that can dramatically shorten research duration, cut research cost and accelerate the development of glass materials. In this work, the ridge regression (RR) analysis was used to construct regression models for predicting the compositional dependence of CaO-Al2O3-SiO2 glass elastic moduli (Shear, Bulk, and Young’s moduli) and hardness based on the ternary diagram of the compositions. The property prediction over a large glass composition space was accomplished with known experimental data of various compositions in the literature, and the simulated results are in good agreement with the measured ones. This regression model can serve as a facile and effective tool for studying the relationship between the compositions and the property, enabling high-efficient design of glasses to meet the requirements for specific elasticity and hardness.

  18. Young's moduli of carbon materials investigated by various classical molecular dynamics schemes

    Science.gov (United States)

    Gayk, Florian; Ehrens, Julian; Heitmann, Tjark; Vorndamme, Patrick; Mrugalla, Andreas; Schnack, Jürgen

    2018-05-01

    For many applications classical carbon potentials together with classical molecular dynamics are employed to calculate structures and physical properties of such carbon-based materials where quantum mechanical methods fail either due to the excessive size, irregular structure or long-time dynamics. Although such potentials, as for instance implemented in LAMMPS, yield reasonably accurate bond lengths and angles for several carbon materials such as graphene, it is not clear how accurate they are in terms of mechanical properties such as for instance Young's moduli. We performed large-scale classical molecular dynamics investigations of three carbon-based materials using the various potentials implemented in LAMMPS as well as the EDIP potential of Marks. We show how the Young's moduli vary with classical potentials and compare to experimental results. Since classical descriptions of carbon are bound to be approximations it is not astonishing that different realizations yield differing results. One should therefore carefully check for which observables a certain potential is suited. Our aim is to contribute to such a clarification.

  19. Laser ultrasonic assessment of the effects of porosity and microcracking on the elastic moduli of nuclear graphites

    International Nuclear Information System (INIS)

    Spicer, James B.; Olasov, Lauren R.; Zeng, Fan W.; Han, Karen; Gallego, Nidia C.; Contescu, Cristian I.

    2016-01-01

    Laser ultrasonic methods have been used to measure the elastic moduli of various nuclear graphites. Measurements were made to assess wavespeeds for longitudinal and shear waves in different propagation directions and these were used along with density measurements to compute the longitudinal and shear moduli as well as Young's modulus. All moduli decreased with increasing graphite porosity and these variations could be interpreted using models describing the effect of porosity on material stiffness. Extrapolations for these models to zero porosity were used to infer the moduli for theoretically dense graphite; the results were far below predicted values reported in the literature for fully dense, polycrystalline, isotropic graphite. Differences can be attributed to microcracking in the graphite microstructure. Using models for the effects of microcracking on modulus, estimates for microcrack populations indicate that the number of cracks per unit volume must be much greater than the number of pores per unit volume. Experimental results reported in the literature for irradiated graphites as well as for the stress dependence of graphite modulus are consistent with the influence of microcracking on elastic behavior and could be interpreted using concepts developed here. Results in this work for graphite structure-property relationships should allow for more sophisticated characterization of nuclear graphites using ultrasonic methods. - Highlights: • Moduli of nuclear graphites measured using laser ultrasonic methods. • Estimates made for the moduli of fully dense, polycrystalline, isotropic graphite. • Models for modulus used to assess effects of microcracking on stiffness. • Microcrack densities estimated using models for effect of microcracks on modulus.

  20. Abelian monopoles: the case of a positive-dimensional moduli space

    International Nuclear Information System (INIS)

    Tyurin, N A

    2000-01-01

    In this paper we consider (in the framework of the general Seiberg-Witten theory) the case when the moduli space of solutions of the Seiberg-Witten equations has positive even dimension. We describe a connection between the Seiberg-Witten invariants of a given manifold X and those of the connected sum Y=X ++ d(CP)-bar 2 where d=(1/2)v. dimM SW . We introduce the notion of a complex structure with degeneration (based on the connection between spinor geometry and complex geometry) and generalize the notion of a pseudoholomorphic curve to the case when the underlying manifold a priori has no almost complex structure

  1. Shear Moduli for Non-Isotropic, Open Cell Foams Using a General Elongated Kelvin Foam Model

    Science.gov (United States)

    Sullivan, Roy M.; Ghosn, Louis J.

    2009-01-01

    Equations for calculating the shear modulus of non-isotropic, open cell foams in the plane perpendicular to the rise direction and in a plane parallel to the rise direction are derived using an elongated Kelvin foam model. This Kelvin foam model is more general than that employed by previous authors as the size and shape of the unit cell are defined by specifying three independent cell dimensions. The equations for the shear compliances are derived as a function of three unit cell dimensions and the section properties of the cell edges. From the compliance equations, the shear modulus equations are obtained and written as a function of the relative density and two unit cell shape parameters. The dependence of the two shear moduli on the relative density and the two shape parameters is demonstrated.

  2. Topological recursion for chord diagrams, RNA complexes, and cells in moduli spaces

    DEFF Research Database (Denmark)

    Andersen, Jørgen Goul; chekhov, Leonid; Penner, Robert

    2013-01-01

    We introduce and study the Hermitian matrix model with potential V(x)=x^2/2-stx/(1-tx), which enumerates the number of linear chord diagrams of fixed genus with specified numbers of backbones generated by s and chords generated by t. For the one-cut solution, the partition function, correlators a...... topology as well as the number of cells in Riemann's moduli spaces for bordered surfaces. The free energies are computed here in principle for all genera and explicitly for genera less than four....... and free energies are convergent for small t and all s as a perturbation of the Gaussian potential, which arises for st=0. This perturbation is computed using the formalism of the topological recursion. The corresponding enumeration of chord diagrams gives at once the number of RNA complexes of a given...

  3. Bulk moduli and equations of state of ice VII and ice VIII

    Science.gov (United States)

    Klotz, S.; Komatsu, K.; Kagi, H.; Kunc, K.; Sano-Furukawa, A.; Machida, S.; Hattori, T.

    2017-05-01

    The compression behavior of deuterated ice VII and VIII was investigated by high pressure neutron scattering in the pressure range 2-13.7 GPa between 93 and 300 K. We establish equations of state which contain accurate values for the bulk moduli B0, their pressure derivatives B0', as well as the ambient pressure volume V0. These equations of state hold over a large part of the stability domain of ice VII, by comparison with available x-ray data, and to at least ≈13 GPa for ice VIII. They are indistinguishable at low pressures, but beyond ≈7 GPa and at low temperatures ice VIII appears to become stiffer than expected. This might be related to an anomalous phonon hardening observed previously in ice VIII in this P /T range [D. D. Klug et al., Phys. Rev. B 70, 144113 (2004), 10.1103/PhysRevB.70.144113].

  4. The moduli space of instantons on an ALE space from 3d $\\mathcal{N}=4$ field theories

    CERN Document Server

    Mekareeya, Noppadol

    2015-01-01

    The moduli space of instantons on an ALE space is studied using the moduli space of $\\mathcal{N}=4$ field theories in three dimensions. For instantons in a simple gauge group $G$ on $\\mathbb{C}^2/\\mathbb{Z}_n$, the Hilbert series of such an instanton moduli space is computed from the Coulomb branch of the quiver given by the affine Dynkin diagram of $G$ with flavour nodes of unitary groups attached to various nodes of the Dynkin diagram. We provide a simple prescription to determine the ranks and the positions of these flavour nodes from the order of the orbifold $n$ and from the residual subgroup of $G$ that is left unbroken by the monodromy of the gauge field at infinity. For $G$ a simply laced group of type $A$, $D$ or $E$, the Higgs branch of such a quiver describes the moduli space of instantons in projective unitary group $PU(n) \\cong U(n)/U(1)$ on orbifold $\\mathbb{C}^2/\\hat{G}$, where $\\hat{G}$ is the discrete group that is in McKay correspondence to $G$. Moreover, we present the quiver whose Coulomb ...

  5. The cohomology ring of the real locus of the moduli space of stable curves of genus 0 with marked points

    NARCIS (Netherlands)

    Etingof, P.; Henriques, A.G.; Kamnitzer, J.; Rains, E.M.

    2010-01-01

    We compute the Poincaré polynomial and the cohomology algebra with rational coefficients of the manifold Mn of real points of the moduli space of algebraic curves of genus 0 with n labeled points. This cohomology is a quadratic algebra, and we conjecture that it is Koszul. We also compute the

  6. A Mechanics Model for Sensors Imperfectly Bonded to the Skin for Determination of the Young's Moduli of Epidermis and Dermis

    Science.gov (United States)

    Yuan, J. H.; Shi, Y.; Pharr, M.; Feng, X.; Rogers, John A.; Huang, Yonggang

    2016-01-01

    A mechanics model is developed for the encapsulated piezoelectric thin-film actuators/sensors system imperfectly bonded to the human skin to simultaneously determine the Young's moduli of the epidermis and dermis as well as the thickness of epidermis. PMID:27330219

  7. Bottom-up approach to moduli dynamics in heavy gravitino scenario: Superpotential, soft terms, and sparticle mass spectrum

    International Nuclear Information System (INIS)

    Endo, Motoi; Yamaguchi, Masahiro; Yoshioka, Koichi

    2005-01-01

    The physics of moduli fields is examined in the scenario where the gravitino is relatively heavy with mass of order 10 TeV, which is favored in view of the severe gravitino problem. The form of the moduli superpotential is shown to be determined, if one imposes a phenomenological requirement that no physical CP phase arise in gaugino masses from conformal anomaly mediation. This bottom-up approach allows only two types of superpotential, each of which can have its origins in a fundamental underlying theory such as superstring. One superpotential is the sum of an exponential and a constant, which is identical to that obtained by Kachru et al. (KKLT), and the other is the racetrack superpotential with two exponentials. The general form of soft supersymmetry-breaking masses is derived, and the pattern of the superparticle mass spectrum in the minimal supersymmetric standard model is discussed with the KKLT-type superpotential. It is shown that the moduli mediation and the anomaly mediation make comparable contributions to the soft masses. At the weak scale, the gaugino masses are rather degenerate compared to the minimal supergravity, which bring characteristic features on the superparticle masses. In particular, the lightest neutralino, which often constitutes the lightest superparticle and thus a dark matter candidate, is a considerable admixture of gauginos and Higgsinos. We also find a small mass hierarchy among the moduli, gravitino, and superpartners of the standard-model fields. Cosmological implications of the scenario are briefly described

  8. Direct micromechanics derivation and DEM confirmation of the elastic moduli of isotropic particulate materials: Part I No particle rotation

    Science.gov (United States)

    Fleischmann, J. A.; Drugan, W. J.; Plesha, M. E.

    2013-07-01

    We derive the macroscopic elastic moduli of a statistically isotropic particulate aggregate material via the homogenization methods of Voigt (1928) (kinematic hypothesis), Reuss (1929) (static hypothesis), and Hershey (1954) and Kröner (1958) (self-consistent hypothesis), originally developed to treat crystalline materials, from the directionally averaged elastic moduli of three regular cubic packings of uniform spheres. We determine analytical expressions for these macroscopic elastic moduli in terms of the (linearized) elastic inter-particle contact stiffnesses on the microscale under the three homogenization assumptions for the three cubic packings (simple, body-centered, and face-centered), assuming no particle rotation. To test these results and those in the literature, we perform numerical simulations using the discrete element method (DEM) to measure the overall elastic moduli of large samples of randomly packed uniform spheres with constant normal and tangential contact stiffnesses (linear spring model). The beauty of DEM is that simulations can be run with particle rotation either prohibited or unrestrained. In this first part of our two-part series of papers, we perform DEM simulations with particle rotation prohibited, and we compare these results with our theoretical results that assumed no particle rotation. We show that the self-consistent homogenization assumption applied to the locally body-centered cubic (BCC) packing most accurately predicts the measured values of the overall elastic moduli obtained from the DEM simulations, in particular Poisson's ratio. Our new analytical self-consistent results lead to significantly better predictions of Poisson's ratio than all prior published theoretical results. Moreover, our results are based on a direct micromechanics analysis of specific geometrical packings of uniform spheres, in contrast to all prior theoretical analyses, which were based on difficult-to-verify hypotheses involving overall inter

  9. Elastic properties and spectroscopic studies of Na 2 O–ZnO–B 2 O 3 ...

    Indian Academy of Sciences (India)

    Elastic properties, 11B MAS–NMR and IR spectroscopic studies have been employed to study the structure of Na2O–ZnO–B2O3 glasses. Sound velocities and elastic moduli such as longitudinal, Young's, bulk and shear modulus have been measured at a frequency of 10 MHz as a function of ZnO concentration.

  10. Elastic properties and spectroscopic studies of Na2O–ZnO–B2O3 ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Elastic properties, 11B MAS–NMR and IR spectroscopic studies have been employed to study the structure of Na2O–ZnO–B2O3 glasses. Sound velocities and elastic moduli such as longitudinal, Young's, bulk and shear modulus have been measured at a frequency of 10 MHz as a function of ZnO concentration.

  11. Rock Physical Interpretation of the Relationship between Dynamic and Static Young's Moduli of Sedimentary Rocks

    Science.gov (United States)

    Takahashi, T.

    2017-12-01

    The static Young's modulus (deformability) of a rock is indispensable for designing and constructing tunnels, dams and underground caverns in civil engineering. Static Young's modulus which is an elastic modulus at large strain level is usually obtained with the laboratory tests of rock cores sampled in boreholes drilled in a rock mass. A deformability model of the entire rock mass is then built by extrapolating the measurements based on a rock mass classification obtained in geological site characterization. However, model-building using data obtained from a limited number of boreholes in the rock mass, especially a complex rock mass, may cause problems in the accuracy and reliability of the model. On the other hand, dynamic Young's modulus which is the modulus at small strain level can be obtained from seismic velocity. If dynamic Young's modulus can be rationally converted to static one, a seismic velocity model by the seismic method can be effectively used to build a deformability model of the rock mass. In this study, we have, therefore, developed a rock physics model (Mavko et al., 2009) to estimate static Young's modulus from dynamic one for sedimentary rocks. The rock physics model has been generally applied to seismic properties at small strain level. In the proposed model, however, the sandy shale model, one of rock physics models, is extended for modeling the static Young's modulus at large strain level by incorporating the mixture of frictional and frictionless grain contacts into the Hertz-Mindlin model. The proposed model is verified through its application to the dynamic Young's moduli derived from well log velocities and static Young's moduli measured in the tri-axial compression tests of rock cores sampled in the same borehole as the logs were acquired. This application proves that the proposed rock physics model can be possibly used to estimate static Young's modulus (deformability) which is required in many types of civil engineering applications

  12. Real-time monitoring of complex moduli from micro-rheology

    International Nuclear Information System (INIS)

    Yanagishima, Taiki; Kotar, Jurij; Eiser, Erika; Frenkel, Daan

    2011-01-01

    We describe an approach to on-line analysis of micro-rheology data using a multi-scale time-correlation method. The method is particularly suited to processing high-volume data streams and compressing the relevant information in real time. Using this, we can obtain complex moduli of visco-elastic media without our method suffering from the high-frequency artefacts that are associated with the truncation errors in the most widely used versions of micro-rheology. Moreover, the present approach obviates the need to choose the time interval for data acquisition beforehand. We test our approach first on an artificial data set and then on experimental data obtained both for an optically trapped colloidal probe in water and for a similar probe in polyethylene glycol solutions at various concentrations. In all cases, we obtain good agreement with the bulk rheology data in the region of overlap. We compare our method with the conventional Kramers-Kronig (KK) transform approach and find that the two methods agree over most of the frequency regime. For the same data set, the present approach is superior to the KK one at high frequencies and can be made to perform at least comparably at low frequencies.

  13. Multi-Regge kinematics and the moduli space of Riemann spheres with marked points

    CERN Document Server

    Del Duca, Vittorio; Drummond, James; Duhr, Claude; Dulat, Falko; Marzucca, Robin; Papathanasiou, Georgios; Verbeek, Bram

    2016-08-25

    We show that scattering amplitudes in planar N = 4 Super Yang-Mills in multi-Regge kinematics can naturally be expressed in terms of single-valued iterated integrals on the moduli space of Riemann spheres with marked points. As a consequence, scattering amplitudes in this limit can be expressed as convolutions that can easily be computed using Stokes' theorem. We apply this framework to MHV amplitudes to leading-logarithmic accuracy (LLA), and we prove that at L loops all MHV amplitudes are determined by amplitudes with up to L + 4 external legs. We also investigate non-MHV amplitudes, and we show that they can be obtained by convoluting the MHV results with a certain helicity flip kernel. We classify all leading singularities that appear at LLA in the Regge limit for arbitrary helicity configurations and any number of external legs. Finally, we use our new framework to obtain explicit analytic results at LLA for all MHV amplitudes up to five loops and all non-MHV amplitudes with up to eight external legs and...

  14. Temperature- and thickness-dependent elastic moduli of polymer thin films

    Directory of Open Access Journals (Sweden)

    Ao Zhimin

    2011-01-01

    Full Text Available Abstract The mechanical properties of polymer ultrathin films are usually different from those of their counterparts in bulk. Understanding the effect of thickness on the mechanical properties of these films is crucial for their applications. However, it is a great challenge to measure their elastic modulus experimentally with in situ heating. In this study, a thermodynamic model for temperature- (T and thickness (h-dependent elastic moduli of polymer thin films Ef(T,h is developed with verification by the reported experimental data on polystyrene (PS thin films. For the PS thin films on a passivated substrate, Ef(T,h decreases with the decreasing film thickness, when h is less than 60 nm at ambient temperature. However, the onset thickness (h*, at which thickness Ef(T,h deviates from the bulk value, can be modulated by T. h* becomes larger at higher T because of the depression of the quenching depth, which determines the thickness of the surface layer δ.

  15. An in situ estimation of anisotropic elastic moduli for a submarine shale

    Science.gov (United States)

    Miller, Douglas E.; Leaney, Scott; Borland, William H.

    1994-11-01

    Direct arrival times and slownesses from wide-aperture walkaway vertical seismic profile data acquired in a layered anisotropic medium can be processed to give direct estimate of the phase slowness surface associated with the medium at the depth of the receivers. This slowness surface can, in turn, be fit by an estimated transversely isotropic medium with a vertical symmetry axis (a 'TIV' medium). While the method requires that the medium between the receivers and the surface be horizontally stratified, no further measurement or knowledge of that medium is required. When applied to data acquired in a compacting shale sequence (here termed the 'Petronas shale') encountered by a well in the South China Sea, the method yields an estimated TIV medium that fits the data extremely well over 180 deg of propagation angles sampled by 201 source positions. The medium is strongly anisotropic. The anisotropy is significantly anelliptic and implies that the quasi-shear mode should be triplicated for off-axis propagation. Estimated density-normalized moduli (in units of sq km/sq s) for the Petronas shale are A(sub 11) = 6.99 +/- 0.21, A(sub 33) = 5.53 +/- 0.17, A(sub 55) = 0.91 +/- 0.05, and A(sub 13) = 2.64 +/- 0.26. Densities in the logged zone just below the survey lie in the range between 2200 and 2400 kg/cu m with an average value close to 2300 kg/cu m.

  16. Preparation and Elastic Moduli of Germanate Glass Containing Lead and Bismuth

    Directory of Open Access Journals (Sweden)

    Wan M. M. Yunus

    2012-04-01

    Full Text Available This paper reports the rapid melt quenching technique preparation for the new family of bismuth-lead germanate glass (BPG systems in the form of (GeO260–(PbO40−x–(½Bi2O3x where x = 0 to 40 mol%. Their densities with respect of Bi2O3 concentration were determined using Archimedes’ method with acetone as a floatation medium. The current experimental data are compared with those of bismuth lead borate (B2O320–(PbO80−x–(Bi2O3x. The elastic properties of BPG were studied using the ultrasonic pulse-echo technique where both longitudinal and transverse sound wave velocities have been measured in each glass samples at a frequency of 15 MHz and at room temperature. Experimental data shows that all the physical parameters of BPG including density and molar volume, both longitudinal and transverse velocities increase linearly with increasing of Bi2O3 content in the germanate glass network. Their elastic moduli such as longitudinal, shear and Young’s also increase linearly with addition of Bi2O3 but the bulk modulus did not. The Poisson’s ratio and fractal dimensionality are also found to vary linearly with the Bi2O3 concentration.

  17. Multi-Regge kinematics and the moduli space of Riemann spheres with marked points

    Energy Technology Data Exchange (ETDEWEB)

    Duca, Vittorio Del [Institute for Theoretical Physics, ETH Zürich,Hönggerberg, 8093 Zürich (Switzerland); Druc, Stefan; Drummond, James [School of Physics & Astronomy, University of Southampton,Highfield, Southampton, SO17 1BJ (United Kingdom); Duhr, Claude [Theoretical Physics Department, CERN,Route de Meyrin, CH-1211 Geneva 23 (Switzerland); Center for Cosmology, Particle Physics and Phenomenology (CP3),Université catholique de Louvain,Chemin du Cyclotron 2, 1348 Louvain-La-Neuve (Belgium); Dulat, Falko [SLAC National Accelerator Laboratory, Stanford University,Stanford, CA 94309 (United States); Marzucca, Robin [Center for Cosmology, Particle Physics and Phenomenology (CP3),Université catholique de Louvain,Chemin du Cyclotron 2, 1348 Louvain-La-Neuve (Belgium); Papathanasiou, Georgios [SLAC National Accelerator Laboratory, Stanford University,Stanford, CA 94309 (United States); Verbeek, Bram [Center for Cosmology, Particle Physics and Phenomenology (CP3),Université catholique de Louvain,Chemin du Cyclotron 2, 1348 Louvain-La-Neuve (Belgium)

    2016-08-25

    We show that scattering amplitudes in planar N=4 Super Yang-Mills in multi-Regge kinematics can naturally be expressed in terms of single-valued iterated integrals on the moduli space of Riemann spheres with marked points. As a consequence, scattering amplitudes in this limit can be expressed as convolutions that can easily be computed using Stokes’ theorem. We apply this framework to MHV amplitudes to leading-logarithmic accuracy (LLA), and we prove that at L loops all MHV amplitudes are determined by amplitudes with up to L+4 external legs. We also investigate non-MHV amplitudes, and we show that they can be obtained by convoluting the MHV results with a certain helicity flip kernel. We classify all leading singularities that appear at LLA in the Regge limit for arbitrary helicity configurations and any number of external legs. Finally, we use our new framework to obtain explicit analytic results at LLA for all MHV amplitudes up to five loops and all non-MHV amplitudes with up to eight external legs and four loops.

  18. Preparation and Elastic Moduli of Germanate Glass Containing Lead and Bismuth

    Science.gov (United States)

    Sidek, Hj A. A.; Bahari, Hamid R.; Halimah, Mohamed K.; Yunus, Wan M. M.

    2012-01-01

    This paper reports the rapid melt quenching technique preparation for the new family of bismuth-lead germanate glass (BPG) systems in the form of (GeO2)60–(PbO)40−x–(½Bi2O3)x where x = 0 to 40 mol%. Their densities with respect of Bi2O3 concentration were determined using Archimedes’ method with acetone as a floatation medium. The current experimental data are compared with those of bismuth lead borate (B2O3)20–(PbO)80−x–(Bi2O3)x. The elastic properties of BPG were studied using the ultrasonic pulse-echo technique where both longitudinal and transverse sound wave velocities have been measured in each glass samples at a frequency of 15 MHz and at room temperature. Experimental data shows that all the physical parameters of BPG including density and molar volume, both longitudinal and transverse velocities increase linearly with increasing of Bi2O3 content in the germanate glass network. Their elastic moduli such as longitudinal, shear and Young’s also increase linearly with addition of Bi2O3 but the bulk modulus did not. The Poisson’s ratio and fractal dimensionality are also found to vary linearly with the Bi2O3 concentration. PMID:22606000

  19. Direct micromechanics derivation and DEM confirmation of the elastic moduli of isotropic particulate materials:. Part II Particle rotation

    Science.gov (United States)

    Fleischmann, J. A.; Drugan, W. J.; Plesha, M. E.

    2013-07-01

    In Part I, Fleischmann et al. (2013), we performed theoretical analyses of three cubic packings of uniform spheres (simple, body-centered, and face-centered) assuming no particle rotation, employed these results to derive the effective elastic moduli for a statistically isotropic particulate material, and assessed these results by performing numerical discrete element method (DEM) simulations with particle rotations prohibited. In this second part, we explore the effect that particle rotation has on the overall elastic moduli of a statistically isotropic particulate material. We do this both theoretically, by re-analyzing the elementary cells of the three cubic packings with particle rotation allowed, which leads to the introduction of an internal parameter to measure zero-energy rotations at the local level, and numerically via DEM simulations in which particle rotation is unrestrained. We find that the effects of particle rotation cannot be neglected. For unrestrained particle rotation, we find that the self-consistent homogenization assumption applied to the locally body-centered cubic packing incorporating particle rotation effects most accurately predicts the measured values of the overall elastic moduli obtained from the DEM simulations, in particular Poisson's ratio. Our new self-consistent results and theoretical modeling of particle rotation effects together lead to significantly better theoretical predictions of Poisson's ratio than all prior published results. Moreover, our results are based on a direct micromechanics analysis of specific geometrical packings of uniform spheres, in contrast to prior theoretical analyses based on hypotheses involving overall inter-particle contact distributions. Thus, our results permit a direct assessment of the reasons for the theory-experiment discrepancies noted in the literature with regard to previous theoretical derivations of the macroscopic elastic moduli for particulate materials, and our new theoretical results

  20. Clarification of the Hashin-Shtrikman bounds on the effective elastic moduli of polycrystals with hexagonal, trigonal, and tetragonal symmetries

    Science.gov (United States)

    Watt, J.P.; Peselnick, L.

    1980-01-01

    Bounds on the effective elastic moduli of randomly oriented aggregates of hexagonal, trigonal, and tetragonal crystals are derived using the variational principles of Hashin and Shtrikman. The bounds are considerably narrower than the widely used Voigt and Reuss bounds. The Voigt-Reuss-Hill average lies within the Hashin-Shtrikman bounds in nearly all cases. Previous bounds of Peselnick and Meister are shown to be special cases of the present results.

  1. Tunable dynamic moduli of magnetic elastomers: from characterization by x-ray micro-computed tomography to mesoscopic modeling

    Science.gov (United States)

    Pessot, Giorgio; Schümann, Malte; Gundermann, Thomas; Odenbach, Stefan; Löwen, Hartmut; Menzel, Andreas M.

    2018-03-01

    Ferrogels and magnetorheological elastomers are composite materials obtained by embedding magnetic particles of mesoscopic size in a crosslinked polymeric matrix. They combine the reversible elastic deformability of polymeric materials with the high responsivity of ferrofluids to external magnetic fields. These materials stand out, for example, for significant magnetostriction as well as a pronounced increase of the elastic moduli in the presence of external magnetic fields. By means of x-ray micro-computed tomography, the position and size of each magnetic particle can be measured with a high degree of accuracy. We here use data extracted from real magnetoelastic samples as input for coarse-grained dipole-spring modeling and calculations to investigate internal restructuring, stiffening, and changes in the normal modes spectrum. More precisely, we assign to each particle a dipole moment proportional to its volume and set a randomized network of springs between them that mimics the behavior of the polymeric elastic matrix. Extending our previously developed methods, we compute the resulting structural changes in the systems as well as the frequency-dependent elastic moduli when magnetic interactions are turned on. Particularly, with increasing magnetization, we observe the formation of chain-like aggregates. Interestingly, the static elastic moduli can first show a slight decrease with growing amplitude of the magnetic interactions, before a pronounced increase appears upon the chain formation. The change of the dynamic moduli with increasing magnetization depends on the frequency and can even feature nonmonotonic behavior. Overall, we demonstrate how theory and experiments can complement each other to learn more about the dynamic behavior of this interesting class of materials.

  2. Elastic moduli of biological fibers in a coarse-grained model: crystalline cellulose and β-amyloids.

    Science.gov (United States)

    Poma, Adolfo B; Chwastyk, Mateusz; Cieplak, Marek

    2017-10-25

    We study the mechanical response of cellulose and β-amyloid microfibrils to three types of deformation: tensile, indentational, and shear. The cellulose microfibrils correspond to the allomorphs Iα or Iβ whereas the β-amyloid microfibrils correspond to the polymorphs of either two- or three-fold symmetry. This response can be characterized by three elastic moduli, namely, Y L , Y T , and S. We use a structure-based coarse-grained model to analyze the deformations in a unified manner. We find that each of the moduli is almost the same for the two allomorphs of cellulose but Y L is about 20 times larger than Y T (140 GPa vs. 7 GPa), indicating the existence of significant anisotropy. For cellulose we note that the anisotropy results from the involvement of covalent bonds in stretching. For β-amyloid, the sense of anisotropy is opposite to that of cellulose. In the three-fold symmetry case, Y L is about half of Y T (3 vs. 7) whereas for two-fold symmetry the anisotropy is much larger (1.6 vs. 21 GPa). The S modulus is derived to be 1.2 GPa for three-fold symmetry and one half of it for the other symmetry and 3.0 GPa for cellulose. The values of the moduli reflect deformations in the hydrogen-bond network. Unlike in our theoretical approach, no experiment can measure all three elastic moduli with the same apparatus. However, our theoretical results are consistent with various measured values: typical Y L for cellulose Iβ ranges from 133 to 155 GPa, Y T from 2 to 25 GPa, and S from 1.8 to 3.8 GPa. For β-amyloid, the experimental values of S and Y T are about 0.3 GPa and 3.3 GPa respectively, while the value of Y L has not been reported.

  3. The Moduli Space and M(Atrix) Theory of 9d N=1 Backgrounds of M/String Theory

    Energy Technology Data Exchange (ETDEWEB)

    Aharony, Ofer; /Weizmann Inst. /Stanford U., ITP /SLAC; Komargodski, Zohar; Patir, Assaf; /Weizmann Inst.

    2007-03-21

    We discuss the moduli space of nine dimensional N = 1 supersymmetric compactifications of M theory/string theory with reduced rank (rank 10 or rank 2), exhibiting how all the different theories (including M theory compactified on a Klein bottle and on a Moebius strip, the Dabholkar-Park background, CHL strings and asymmetric orbifolds of type II strings on a circle) fit together, and what are the weakly coupled descriptions in different regions of the moduli space. We argue that there are two disconnected components in the moduli space of theories with rank 2. We analyze in detail the limits of the M theory compactifications on a Klein bottle and on a Moebius strip which naively give type IIA string theory with an uncharged orientifold 8-plane carrying discrete RR flux. In order to consistently describe these limits we conjecture that this orientifold non-perturbatively splits into a D8-brane and an orientifold plane of charge (-1) which sits at infinite coupling. We construct the M(atrix) theory for M theory on a Klein bottle (and the theories related to it), which is given by a 2 + 1 dimensional gauge theory with a varying gauge coupling compactified on a cylinder with specific boundary conditions. We also clarify the construction of the M(atrix) theory for backgrounds of rank 18, including the heterotic string on a circle.

  4. Ceramic strengthening by tuning the elastic moduli of resin-based luting agents.

    Science.gov (United States)

    Spazzin, Aloísio O; Bacchi, Ataís; Alessandretti, Rodrigo; Santos, Mateus B; Basso, Gabriela R; Griggs, Jason; Moraes, Rafael R

    2017-03-01

    Resin-based luting agents (RBLAs) with tuned elastic moduli (E) were prepared and their influence on the strengthening, reliability, and mode of failure of luted feldspar ceramic was investigated. RBLAs with low E (2.6GPa), intermediate E (6.6GPa), and high E (13.3GPa) were prepared and used to coat acid-etched ceramic disks. Positive (untreated ceramic) and negative (acid-etched ceramic) control groups were tested. The response variables (n=30) were biaxial flexural strength (σ bf , MPa), characteristic strength (σ 0 , MPa), and Weibull modulus at the ceramic surface (z=0) and luting agent surface (z=-t 2 ). A 3D finite element analysis simulated the biaxial flexural test. Fractographic analysis and morphology of the bonded interfaces were analyzed using scanning electron microscopy. The RBLAs improved σ bf and σ 0 at z=0, particularly those with intermediate and high E, whereas the mechanical reliability was only affected in the negative control. At z=-t 2 , differences between all RBLAs were observed but the structural reliability was independent of the RBLA tested. Increasing E of the RBLA was associated with increased stress concentration at the RBLA and reduced stresses reaching the ceramic. Failures originated on the ceramic surface at the ceramic-cement interface. In the high E group, failure sometimes originated from the RBLA free surface. All RBLAs completely filled the ceramic irregularities. Increased E of the RBLA reduced the variability of strength, the stress reaching the ceramic structure, and sometimes altered the origin of failure. The use of high E RBLAs seems beneficial for luting feldspar ceramics. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  5. NASA/University JOint VEnture (JOVE) Program: Transverse Shear Moduli Using the Torsional Responses of Rectangular Laminates

    Science.gov (United States)

    Bogan, Sam

    2001-01-01

    The first year included a study of the non-visible damage of composite overwrapped pressure vessels with B. Poe of the Materials Branch of Nasa-Langley. Early determinations showed a clear reduction in non-visible damage for thin COPVs when partially pressurized rather than unpressurized. Literature searches on Thicker-wall COPVs revealed surface damage but clearly visible. Analysis of current Analytic modeling indicated that that current COPV models lacked sufficient thickness corrections to predict impact damage. After a comprehensive study of available published data and numerous numerical studies based on observed data from Langley, the analytic framework for modeling the behavior was determined lacking and both Poe and Bogan suggested any short term (3yr) result for Jove would be overly ambitious and emphasis should be placed on transverse shear moduli studies. Transverse shear moduli determination is relevant to the study of fatigue, fracture and aging effects in composite structures. Based on the techniques developed by Daniel & Tsai, Bogan and Gates determined to verify the results for K3B and 8320. A detailed analytic and experimental plan was established and carried out that included variations in layup, width, thickness, and length. As well as loading rate variations to determine effects and relaxation moduli. The additional axial loads during the torsion testing were studied as was the placement of gages along the composite specimen. Of the proposed tasks, all of tasks I and 2 were completed with presentations given at Langley, SEM conferences and ASME/AIAA conferences. Sensitivity issues with the technique associated with the use of servohydraulic test systems for applying the torsional load to the composite specimen limited the torsion range for predictable and repeatable transverse shear properties. Bogan and Gates determined to diverge on research efforts with Gates continuing the experimental testing at Langley and Bogan modeling the apparent non

  6. A mathematical model for the determination of forming tissue moduli in needled-nonwoven scaffolds.

    Science.gov (United States)

    Soares, João S; Zhang, Will; Sacks, Michael S

    2017-03-15

    Formation of engineering tissues (ET) remains an important scientific area of investigation for both clinical translational and mechanobiological studies. Needled-nonwoven (NNW) scaffolds represent one of the most ubiquitous biomaterials based on their well-documented capacity to sustain tissue formation and the unique property of substantial construct stiffness amplification, the latter allowing for very sensitive determination of forming tissue modulus. Yet, their use in more fundamental studies is hampered by the lack of: (1) substantial understanding of the mechanics of the NNW scaffold itself under finite deformations and means to model the complex mechanical interactions between scaffold fibers, cells, and de novo tissue; and (2) rational models with reliable predictive capabilities describing their evolving mechanical properties and their response to mechanical stimulation. Our objective is to quantify the mechanical properties of the forming ET phase in constructs that utilize NNW scaffolds. We present herein a novel mathematical model to quantify their stiffness based on explicit considerations of the modulation of NNW scaffold fiber-fiber interactions and effective fiber stiffness by surrounding de novo ECM. Specifically, fibers in NNW scaffolds are effectively stiffer than if acting alone due to extensive fiber-fiber cross-over points that impart changes in fiber geometry, particularly crimp wavelength and amplitude. Fiber-fiber interactions in NNW scaffolds also play significant role in the bulk anisotropy of the material, mainly due to fiber buckling and large translational out-of-plane displacements occurring to fibers undergoing contraction. To calibrate the model parameters, we mechanically tested impregnated NNW scaffolds with polyacrylamide (PAM) gels with a wide range of moduli with values chosen to mimic the effects of surrounding tissues on the scaffold fiber network. Results indicated a high degree of model fidelity over a wide range of planar

  7. U(N) instantons on N=(1/2) superspace: Exact solution and geometry of moduli space

    International Nuclear Information System (INIS)

    Britto, Ruth; Feng Bo; Lunin, Oleg; Rey, Soo-Jong

    2004-01-01

    We construct the exact solution of one (anti-)instanton in N=(1/2) super Yang-Mills theory defined on non(anti-)commutative superspace. We first identify N=(1/2) superconformal invariance as maximal spacetime symmetry. For the gauge group U(2), the SU(2) part of the solution is given by the standard (anti-)instanton, but the U(1) field strength also turns out to be nonzero. The solution is SO(4) rotationally symmetric. For the gauge group U(N), in contrast with the U(2) case, we show that the entire U(N) part of the solution is deformed by non(anti-)commutativity and fermion zero modes. The solution is no longer rotationally symmetric; it is polarized into an axially symmetric configuration because of the underlying non(anti-)commutativity. We compute the 'information metric' of one (anti-)instanton. We find that the moduli space geometry is deformed from the hyperbolic space H 5 (Euclidean anti-de Sitter space) in a way anticipated from reduced spacetime symmetry. Remarkably, the volume measure of the moduli space turns out to be independent of the non(anti-)commutativity. Implications for D branes in the Ramond-Ramond flux background and the gauge-gravity correspondence are discussed

  8. Modal Damping Ratio and Optimal Elastic Moduli of Human Body Segments for Anthropometric Vibratory Model of Standing Subjects.

    Science.gov (United States)

    Gupta, Manoj; Gupta, T C

    2017-10-01

    The present study aims to accurately estimate inertial, physical, and dynamic parameters of human body vibratory model consistent with physical structure of the human body that also replicates its dynamic response. A 13 degree-of-freedom (DOF) lumped parameter model for standing person subjected to support excitation is established. Model parameters are determined from anthropometric measurements, uniform mass density, elastic modulus of individual body segments, and modal damping ratios. Elastic moduli of ellipsoidal body segments are initially estimated by comparing stiffness of spring elements, calculated from a detailed scheme, and values available in literature for same. These values are further optimized by minimizing difference between theoretically calculated platform-to-head transmissibility ratio (TR) and experimental measurements. Modal damping ratios are estimated from experimental transmissibility response using two dominant peaks in the frequency range of 0-25 Hz. From comparison between dynamic response determined form modal analysis and experimental results, a set of elastic moduli for different segments of human body and a novel scheme to determine modal damping ratios from TR plots, are established. Acceptable match between transmissibility values calculated from the vibratory model and experimental measurements for 50th percentile U.S. male, except at very low frequencies, establishes the human body model developed. Also, reasonable agreement obtained between theoretical response curve and experimental response envelop for average Indian male, affirms the technique used for constructing vibratory model of a standing person. Present work attempts to develop effective technique for constructing subject specific damped vibratory model based on its physical measurements.

  9. The (orbifold) Euler characteristic of the moduli space of curves and the continuum limit of Penner's connected generating function

    International Nuclear Information System (INIS)

    Chair, N.

    1990-08-01

    The generating function that gives rise to the orbifold Euler characteristic of the moduli space of punctured compact Riemann surfaces X(M s g ), g≥0 is derived explicitly. In the derivation, we show that we do not need to use the three-term recursion relation for the orthogonal polynomials. Also the continuum limit of Penner's connected generating function is considered and is shown to be formally equivalent to the free energy obtained recently by Distler and Vafa which exhibits the logarithmic divergences found for genus zero and one in D=1 matrix models. Finally, it is shown that the free energy and its s-derivatives are nothing but the continuum limit of a certain generating function introduced by Harer and Zagier in obtaining the true Euler characteristic with any number of punctures, e(Γ g s ), s≥0. (author). 13 refs

  10. Quantization vial real polarization of the moduli space of flat connections and Chern-Simons gauge theory in genus one

    International Nuclear Information System (INIS)

    Weitsman, J.; Harvard Univ., Cambridge, MA

    1991-01-01

    We study the quantization of the moduli space of flat connections on a surface of genus one, using the real polarization of this space. The quantum wave functions in this formalism are exponential functions supported along the integral fibres of the polarization. The space of wave functions obtained in this way is isomorphic to a space of theta functions. We use our construction to cunstruct part of what may be a topological field theory in genus one, and to compute the associated invariants of some three manifolds. These computations agree with those of Witten, but the invariants are expressed as sums of quantities computed at a discrete set of connections with curvature concentrated on a link in the three manifold. A similar prescription is used to produce knot invariants. (orig.)

  11. Origin of the multiple configurations that drive the response of δ-plutonium’s elastic moduli to temperature

    Science.gov (United States)

    Migliori, Albert; Söderlind, Per; Landa, Alexander; Freibert, Franz J.; Maiorov, Boris; Ramshaw, B. J.; Betts, Jon B.

    2016-01-01

    The electronic and thermodynamic complexity of plutonium has resisted a fundamental understanding for this important elemental metal. A critical test of any theory is the unusual softening of the bulk modulus with increasing temperature, a result that is counterintuitive because no or very little change in the atomic volume is observed upon heating. This unexpected behavior has in the past been attributed to competing but never-observed electronic states with different bonding properties similar to the scenario with magnetic states in Invar alloys. Using the recent observation of plutonium dynamic magnetism, we construct a theory for plutonium that agrees with relevant measurements by using density-functional-theory (DFT) calculations with no free parameters to compute the effect of longitudinal spin fluctuations on the temperature dependence of the bulk moduli in δ-Pu. We show that the softening with temperature can be understood in terms of a continuous distribution of thermally activated spin fluctuations. PMID:27647904

  12. Origin of the multiple configurations that drive the response of δ-plutonium's elastic moduli to temperature

    Science.gov (United States)

    Migliori, Albert; Söderlind, Per; Landa, Alexander; Freibert, Franz J.; Maiorov, Boris; Ramshaw, B. J.; Betts, Jon B.

    2016-10-01

    The electronic and thermodynamic complexity of plutonium has resisted a fundamental understanding for this important elemental metal. A critical test of any theory is the unusual softening of the bulk modulus with increasing temperature, a result that is counterintuitive because no or very little change in the atomic volume is observed upon heating. This unexpected behavior has in the past been attributed to competing but never-observed electronic states with different bonding properties similar to the scenario with magnetic states in Invar alloys. Using the recent observation of plutonium dynamic magnetism, we construct a theory for plutonium that agrees with relevant measurements by using density-functional-theory (DFT) calculations with no free parameters to compute the effect of longitudinal spin fluctuations on the temperature dependence of the bulk moduli in δ-Pu. We show that the softening with temperature can be understood in terms of a continuous distribution of thermally activated spin fluctuations.

  13. In search of invariants for viscous liquids in the density scaling regime: investigations of dynamic and thermodynamic moduli.

    Science.gov (United States)

    Jedrzejowska, Agnieszka; Grzybowski, Andrzej; Paluch, Marian

    2017-07-19

    In this paper, we report the nontrivial results of our investigations of dynamic and thermodynamic moduli in search of invariants for viscous liquids in the density scaling regime by using selected supercooled van der Waals liquids as representative materials. Previously, the dynamic modulus M p-T (defined in the pressure-temperature representation by the ratio of isobaric activation energy and activation volume) as well as the ratio B T /M p-T (where B T is the thermodynamic modulus defined as the inverse isothermal compressibility) have been suggested as some kinds of material constants. We have established that they are not valid in the explored wide range of temperatures T over a dozen decades of structural relaxation times τ. The temperature dependences of M p-T and B T /M p-T have been elucidated by comparison with the well-known measure of the relative contribution of temperature and density fluctuations to molecular dynamics near the glass transition, i.e., the ratio of isochoric and isobaric activation energies. Then, we have implemented an idea to transform the definition of the dynamic modulus M p-T from the p-T representation to the V-T one. This idea relied on the disentanglement of combined temperature and density fluctuations involved in isobaric parameters and has resulted in finding an invariant for viscous liquids in the density scaling regime, which is the ratio of thermodynamic and dynamic moduli, B T /M V-T . In this way, we have constituted a characteristic of thermodynamics and molecular dynamics, which remains unchanged in the supercooled liquid state for a given material, the molecular dynamics of which obeys the power density scaling law.

  14. On a stratification of the Kontsevich moduli space ¯M0,n(G(2,4),d)  and enumerative geometry

    DEFF Research Database (Denmark)

    Martinez, Cristina

    2009-01-01

    ‾We consider a particular stratification of the moduli space of stable maps to G(2,4) . As an application we compute the degree of the variety parametrizing rational ruled surfaces with a minimal directrix of degree by studying divisors in this moduli space of stable maps. For example, there are ...

  15. A model for the parabolic slices Per1(e2πip/q) in moduli space of quadratic rational maps

    DEFF Research Database (Denmark)

    Uhre, Eva

    2010-01-01

    The notion of relatedness loci in the parabolic slices Per1(e2πip/q) in moduli space of quadratic rational maps is introduced. They are counterparts of the disconnectedness or escape locus in the slice of quadratic polynomials. A model for these loci is presented, and a strategy of proof of the f...

  16. The L2-metric on the moduli space of SU(2)-instantons with instanton number 1 over the Euclidean 4-space

    International Nuclear Information System (INIS)

    Habermann, L.

    1992-08-01

    The L 2 -metric g 0 on the moduli space M 1 (Q) of self-dual SU(2)-connections with instanton number 1 over the Euclidean 4-space is described. It is shown that the Riemannian manifold (M 1 (Q), g 0 ) is isometric to R + xR 4 with the Euclidean metric. (orig.)

  17. Monte Carlo calculations of the elastic moduli and pressure-volume-temperature equation of state for hexahydro-1,3,5-trinitro-1,3,5-triazine

    International Nuclear Information System (INIS)

    Sewell, Thomas D.; Bennett, Carl M.

    2000-01-01

    Isothermal-isobaric Monte Carlo calculations were used to obtain predictions of the elastic coefficients and derived engineering moduli and Poisson ratios for crystalline hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The elastic coefficients were computed using the strain fluctuation formula due to Rahman and Parrinello [J. Chem. Phys. 76, 2662 (1982)]. Calculations were performed as a function of temperature (218 K≤T≤333 K) and hydrostatic pressure (0 GPa≤p≤4 GPa). The predicted values of the moduli and Poisson ratios under ambient conditions are in accord with general expectations for molecular crystals and with a very recent, unpublished determination for RDX. The moduli exhibit a sensitive pressure dependence whereas the Poisson ratios are relatively independent of pressure. The temperature dependence of the moduli is comparable to the precision of the results. However, the crystal does exhibit thermal softening for most pressures. An additional product of the calculations is information about the pressure-volume-temperature (pVT) equation of state. We obtain near-quantitative agreement with experiment for the case of hydrostatic compression and reasonable, but not quantitative, correspondence for thermal expansion. The results indicate a significant dependence of the thermal expansion coefficients on hydrostatic pressure. (c) 2000 American Institute of Physics

  18. Microstructural dependence on relevant physical-mechanical properties on SiO2-Na2O-CaO-P2O5 biological glasses.

    Science.gov (United States)

    Rajendran, V; Begum, A Nishara; Azooz, M A; el Batal, F H

    2002-11-01

    Bioactive glasses of the system SiO2-Na2O-CaO-P2O5 have been prepared by the normal melting and annealing technique. The elastic moduli, attenuation, Vickers hardness, fracture toughness and fracture surface energy have been obtained using the known method at room temperature. The temperature dependence of elastic moduli and attenuation measurements have been extended over a wide range of temperature from 150 to 500 K. The SiO2 content dependence of velocities, attenuation, elastic moduli, and other parameters show an interesting observation at 45 wt% of SiO2 by exhibiting an anomalous behaviour. A linear relation is developed for Tg, which explores the influence of Na2O on SiO2-Na2O-CaO-P2O5 bioactive glasses. The measured hardness, fracture toughness and fracture surface energy show a linear relation with Young's modulus. It is also interesting to note that the observed results are functions of polymerisation and the number of non-bridging oxygens (NBO) prevailing in the network with change in SiO2 content. The temperature dependence of velocities, attenuation and elastic moduli show the existence of softening in the glass network structure as temperature increases.

  19. Fiber/collagen composites for ligament tissue engineering: influence of elastic moduli of sparse aligned fibers on mesenchymal stem cells.

    Science.gov (United States)

    Thayer, Patrick S; Verbridge, Scott S; Dahlgren, Linda A; Kakar, Sanjeev; Guelcher, Scott A; Goldstein, Aaron S

    2016-08-01

    Electrospun microfibers are attractive for the engineering of oriented tissues because they present instructive topographic and mechanical cues to cells. However, high-density microfiber networks are too cell-impermeable for most tissue applications. Alternatively, the distribution of sparse microfibers within a three-dimensional hydrogel could present instructive cues to guide cell organization while not inhibiting cell behavior. In this study, thin (∼5 fibers thick) layers of aligned microfibers (0.7 μm) were embedded within collagen hydrogels containing mesenchymal stem cells (MSCs), cultured for up to 14 days, and assayed for expression of ligament markers and imaged for cell organization. These microfibers were generated through the electrospinning of polycaprolactone (PCL), poly(ester-urethane) (PEUR), or a 75/25 PEUR/PCL blend to produce microfiber networks with elastic moduli of 31, 15, and 5.6 MPa, respectively. MSCs in composites containing 5.6 MPa fibers exhibited increased expression of the ligament marker scleraxis and the contractile phenotype marker α-smooth muscle actin versus the stiffer fiber composites. Additionally, cells within the 5.6 MPa microfiber composites were more oriented compared to cells within the 15 and 31 MPa microfiber composites. Together, these data indicate that the mechanical properties of microfiber/collagen composites can be tuned for the engineering of ligament and other target tissues. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1894-1901, 2016. © 2016 Wiley Periodicals, Inc.

  20. Evaluation of stem cell-to-tenocyte differentiation by atomic force microscopy to measure cellular elastic moduli.

    Science.gov (United States)

    Morita, Yasuyuki; Mukai, Taichi; Ju, Yang; Watanabe, Sachi

    2013-05-01

    In the present study, we evaluated whether stem cell-to-tenocyte differentiation could be evaluated via measurement of the mechanical properties of the cell. We used mechanical uniaxial cyclic stretching to induce the differentiation of human bone marrow mesenchymal stem cells into tenocytes. The cells were subjected to cyclic elongation of 10 or 15 % at a cyclic frequency of 1 Hz for 24 or 48 h, and differentiation was assessed by real-time PCR (rtPCR) determination of messenger RNA expression levels for four commonly used markers of stem cell-to-tenocyte differentiation: type I collagen, type III collagen, tenascin-C, and scleraxis. The rtPCR results showed that cells subjected to 10 % cyclic elongation for 24 or 48 h differentiated into tenocytes. Atomic force microscopy (AFM) was then used to measure the force curves around the cell nuclei, and the AFM data were used to calculate the elastic moduli of the cell surfaces. The elastic modulus values of the control (non-stretched) cells differed significantly from those of cells stretched at 10 % for 24 or 48 h (P atomic force microscopic measurement of the elastic modulus of the cell surface can be used to evaluate stem cell-to-tenocyte differentiation.

  1. Computational efficiency of numerical approximations of tangent moduli for finite element implementation of a fiber-reinforced hyperelastic material model.

    Science.gov (United States)

    Liu, Haofei; Sun, Wei

    2016-01-01

    In this study, we evaluated computational efficiency of finite element (FE) simulations when a numerical approximation method was used to obtain the tangent moduli. A fiber-reinforced hyperelastic material model for nearly incompressible soft tissues was implemented for 3D solid elements using both the approximation method and the closed-form analytical method, and validated by comparing the components of the tangent modulus tensor (also referred to as the material Jacobian) between the two methods. The computational efficiency of the approximation method was evaluated with different perturbation parameters and approximation schemes, and quantified by the number of iteration steps and CPU time required to complete these simulations. From the simulation results, it can be seen that the overall accuracy of the approximation method is improved by adopting the central difference approximation scheme compared to the forward Euler approximation scheme. For small-scale simulations with about 10,000 DOFs, the approximation schemes could reduce the CPU time substantially compared to the closed-form solution, due to the fact that fewer calculation steps are needed at each integration point. However, for a large-scale simulation with about 300,000 DOFs, the advantages of the approximation schemes diminish because the factorization of the stiffness matrix will dominate the solution time. Overall, as it is material model independent, the approximation method simplifies the FE implementation of a complex constitutive model with comparable accuracy and computational efficiency to the closed-form solution, which makes it attractive in FE simulations with complex material models.

  2. Hydrogen bonds, interfacial stiffness moduli, and the interlaminar shear strength of carbon fiber-epoxy matrix composites

    Directory of Open Access Journals (Sweden)

    John H. Cantrell

    2015-03-01

    Full Text Available The chemical treatment of carbon fibers used in carbon fiber-epoxy matrix composites greatly affects the fraction of hydrogen bonds (H-bonds formed at the fiber-matrix interface. The H-bonds are major contributors to the fiber-matrix interfacial shear strength and play a direct role in the interlaminar shear strength (ILSS of the composite. The H-bond contributions τ to the ILSS and magnitudes KN of the fiber-matrix interfacial stiffness moduli of seven carbon fiber-epoxy matrix composites, subjected to different fiber surface treatments, are calculated from the Morse potential for the interactions of hydroxyl and carboxyl acid groups formed on the carbon fiber surfaces with epoxy receptors. The τ calculations range from 7.7 MPa to 18.4 MPa in magnitude, depending on fiber treatment. The KN calculations fall in the range (2.01 – 4.67 ×1017 N m−3. The average ratio KN/|τ| is calculated to be (2.59 ± 0.043 × 1010 m−1 for the seven composites, suggesting a nearly linear connection between ILSS and H-bonding at the fiber-matrix interfaces. The linear connection indicates that τ may be assessable nondestructively from measurements of KN via a technique such as angle beam ultrasonic spectroscopy.

  3. Line operators in theories of class S, quantized moduli space of flat connections, and Toda field theory

    International Nuclear Information System (INIS)

    Coman, Ioana; Teschner, Joerg

    2015-05-01

    Non-perturbative aspects of N=2 supersymmetric gauge theories of class S are deeply encoded in the algebra of functions on the moduli space M flat of at SL(N)-connections on Riemann surfaces. Expectation values of Wilson and 't Hooft line operators are related to holonomies of flat connections, and expectation values of line operators in the low-energy effective theory are related to Fock-Goncharov coordinates on M flat . Via the decomposition of UV line operators into IR line operators, we determine their noncommutative algebra from the quantization of Fock-Goncharov Laurent polynomials, and find that it coincides with the skein algebra studied in the context of Chern-Simons theory. Another realization of the skein algebra is generated by Verlinde network operators in Toda field theory. Comparing the spectra of these two realizations provides non-trivial support for their equivalence. Our results can be viewed as evidence for the generalization of the AGT correspondence to higher-rank class S theories.

  4. Interneta veikala platformas “Prestashop” modulis priekš preču importa un preču datu atjaunošanas

    OpenAIRE

    Hromčenkova, Veronika

    2017-01-01

    Šī kvalifikācijas darba mērķis izstrādāt moduli priekš produktu importa interneta veikalam uz PrestaShop platformas. Modulī ir iespējams ielādēt failu XML formātā, tas saturs no XML struktūras tiks pārveidots par viegli lietojamo tabulu ar visiem datiem no faila, lietotājs var rediģēt datus tabulā un importēt veikalā. Import PrestaShop veikalā notiek caur PrestaShop tīmekļa pakalpojumu. Modulis atvieglo interneta veikala administratoriem preču importēšanu. Tas ir īpaši aktuāli, ja vajag pārne...

  5. Thermal expansion and elastic moduli of the silicide based intermetallic alloys Ti5Si3(X) and Nb5Si3

    International Nuclear Information System (INIS)

    Zhang, L.; Wu, J.

    1997-01-01

    Silicides are among those potential candidates for high temperature application because of their high melting temperature, low density and good oxidation resistance. Recent interest is focused on molybdenum silicides and titanium silicides. Extensive investigation has been carried out on MoSi 2 , yet comparatively less work was performed on titanium silicides such as Ti 5 Si 3 and Ti 3 and TiSi 2 which are of lower density than MoSi 2 . Fundamental understanding of the titanium silicides' properties for further evaluation their potential for practical application are thus needed. The thermal expansion coefficients and elastic moduli of intermetallic compounds are two properties important for evaluation as a first step. The thermal expansion determines the possible stress that might arise during cooling for these high melting point compounds, which is crucial to the preparation of defect free specimens; and the elastic moduli are usually reflections of the cohesion in crystal. In Frommeyer's work and some works afterwards, the coefficients of thermal expansion were measured on both polycrystalline and single crystal Ti 5 Si 3 . The elastic modulus of polycrystalline Ti 5 Si 3 was measured by Frommeyer and Rosenkranz. However, in the above works, the referred Ti 5 Si 3 was the binary one, no alloying effect has been reported on this matter. Moreover, the above parameters (coefficient of thermal expansion and elastic modulus) of Nb 5 Si 3 remain unreported so far. In this paper, the authors try to extend the knowledge of alloyed Ti 5 Si 3 compounds with Nb and Cr additions. Results on the coefficients of thermal expansion and elastic moduli of Ti 5 Si 3 compounds and Nb 5 Si 3 are presented and the discussion is focused on the alloying effect

  6. Electronic properties and bulk moduli of novel boron nitride polymorphs: hyperdiamond B12N12 and the simple cubic B24N24, B12N12 fulborenites

    International Nuclear Information System (INIS)

    Pokrivnyj, V.V.; Bekenev, V.L.

    2006-01-01

    Equation of states, energy band structure, electronic density of states, and bulk moduli of the boron nitride fulborenite crystals: B 12 N 12 with a diamond lattice and B 24 N 24 , B 12 N 12 with a simple cubic lattice have been calculated for the first time by FLAPW method. Calculated parameters of these compounds are as follows: equilibrium lattice parameter, the length of B-N bond, the number of atoms per conventional cell, density, bulk modulus, band gap. Hyperdiamond B 12 N 12 is shown to have the record bulk modulus B 0 = 658 GPa [ru

  7. Desenvolvimento de um equipamento para a caracterização não-destrutiva dos módulos elásticos de materiais cerâmicos Development of equipment for non-destructive characterization of elastic moduli of ceramic materials

    Directory of Open Access Journals (Sweden)

    A. H. A Pereira

    2010-06-01

    Full Text Available Foi desenvolvido um equipamento para a caracterização não-destrutiva dos módulos elásticos aplicável a cerâmicas, concretos e materiais frágeis baseado na norma ASTM E 1875-00. Pode-se medir com exatidão, praticidade e simultaneidade o módulo de Young, de cisalhamento e a razão de Poisson. O equipamento obtém, via espectroscopia de ressonância sônica, as freqüências naturais de vibração flexurais e torcionais do corpo de prova e calcula os módulos. O equipamento foi desenvolvido em três partes: suporte do corpo de prova, eletrônica e software. O suporte aplica as condições de contorno mecânicas e a excitação necessária, a eletrônica gera e capta os sinais e o software executa os cálculos. A validação foi realizada com ensaios inter-técnicas e inter-laboratoriais de materiais refratários e de referência. Os resultados mostraram que o equipamento é mais versátil do que as opções atuais para a medida simultânea das três propriedades elásticas apresentadas acima.In this work was developed an equipment for non-destructive characterization of elastic moduli applicable to ceramics, concretes, and brittle materials based on ASTM E 1875-00 standard. The Young's modulus, shear modulus and Poisson's ratio can be simultaneously and easily measured with accuracy applying the new equipment. The natural torsional and flexural vibration frequencies of the sample are measured through sonic resonance spectroscopy. This permits the calculation of the elastic moduli. The system was developed in three parts: the sample holder, the electronics and the software. The sample holder applies the mechanical boundary conditions and excitation. The electronics captures and generates the signals. Finally, the software performs the calculations. The validation was carried out with inter-laboratory and inter-technique tests of refractories and reference materials. The results showed that the equipment is more versatile than the current

  8. Moduli stabilization, large-volume dS minimum without D3-bar branes, (non-)supersymmetric black hole attractors and two-parameter Swiss cheese Calabi-Yau's

    CERN Document Server

    Misra, Aalok

    2008-01-01

    We consider issues of moduli stabilization and "area codes" for type II flux compactifications, and the "Inverse Problem" and "Fake Superpotentials" for extremal (non)supersymmetric black holes in type II compactifications on (orientifold of) a compact two-parameter Calabi-Yau expressed as a degree-18 hypersurface in WCP^4[1,1,1,6,9] which has multiple singular loci in its moduli space. We argue the existence of extended "area codes" [1] wherein for the same set of large NS-NS and RR fluxes, one can stabilize all the complex structure moduli and the axion-dilaton modulus (to different sets of values) for points in the moduli space away as well as near the different singular conifold loci leading to the existence of domain walls. By including non-perturbative alpha' and instanton corrections in the Kaehler potential and superpotential [2], we show the possibility of getting a large-volume non-supersymmetric (A)dS minimum. Further, using techniques of [3] we explicitly show that given a set of moduli and choice...

  9. High Elastic Moduli of a 54Al2O3-46Ta2O5 Glass Fabricated via Containerless Processing.

    Science.gov (United States)

    Rosales-Sosa, Gustavo A; Masuno, Atsunobu; Higo, Yuji; Inoue, Hiroyuki; Yanaba, Yutaka; Mizoguchi, Teruyasu; Umada, Takumi; Okamura, Kohei; Kato, Katsuyoshi; Watanabe, Yasuhiro

    2015-10-15

    Glasses with high elastic moduli have been in demand for many years because the thickness of such glasses can be reduced while maintaining its strength. Moreover, thinner and lighter glasses are desired for the fabrication of windows in buildings and cars, cover glasses for smart-phones and substrates in Thin-Film Transistor (TFT) displays. In this work, we report a 54Al2O3-46Ta2O5 glass fabricated by aerodynamic levitation which possesses one of the highest elastic moduli and hardness for oxide glasses also displaying excellent optical properties. The glass was colorless and transparent in the visible region, and its refractive index nd was as high as 1.94. The measured Young's modulus and Vickers hardness were 158.3 GPa and 9.1 GPa, respectively, which are comparable to the previously reported highest values for oxide glasses. Analysis made using (27)Al Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) spectroscopy revealed the presence of a significantly large fraction of high-coordinated Al in addition to four-coordinated Al in the glass. The high elastic modulus and hardness are attributed to both the large cationic field strength of Ta(5+) ions and the large dissociation energies per unit volume of Al2O3 and Ta2O5.

  10. Determination of hoop direction effective elastic moduli of non-circular profile, fiber reinforced polymer composite sewer liner pipes from lateral ring compression tests

    International Nuclear Information System (INIS)

    Czél, Gergely; Takács, Dénes

    2015-01-01

    A new material property determination method is presented for the calculation of effective elastic moduli of non-circular ring specimens cut from filament wound oval profile polymer composite sewer liner pipes. The hoop direction elastic moduli was determined using the test results obtained from ring compression tests, which is a very basic setup, and requires no special equipment. Calculations were executed for many different oval profiles, and diagrams were constructed, from which the cross section dependent C eff constants can be taken. The new method was validated by the comparison of tests and finite element analysis results. The calculation method and the diagrams are essential design tools for engineers, and a big step forward in sizing non-circular profile liner pipes. - Highlights: • A simple modulus measurement method is presented for non-circular ring specimens. • The evaluation method is validated against a finite element model. • Profile shape dependent constants are presented for a wide range of cross-sections. • A set of charts with the constants are provided to aid design engineers.

  11. Covers of the integers with odd moduli and their applications to the forms x^{m}-2^{n} and x^{2}-F_{3n}/2

    Science.gov (United States)

    Wu, Ke-Jian; Sun, Zhi-Wei

    2009-09-01

    In this paper we construct a cover \\{a_{s}(operatorname{mod} n_{s})\\}_{s=1}^{k} of mathbb{Z} with odd moduli such that there are distinct primes p_{1},ldots ,p_{k} dividing 2^{n_{1}}-1,ldots ,2^{n_{k}}-1 respectively. Using this cover we show that for any positive integer m divisible by none of 3, 5, 7, 11, 13 there exists an infinite arithmetic progression of positive odd integers the m th powers of whose terms are never of the form 2^{n}pm p^{a} with a,nin \\{0,1,2,ldots \\} and p a prime. We also construct another cover of mathbb{Z} with odd moduli and use it to prove that x^{2}-F_{3n}/2 has at least two distinct prime factors whenever nin \\{0,1,2,ldots \\} and xeq a (operatorname{mod} M) , where \\{F_{i}\\}_{igeqslant 0} is the Fibonacci sequence, and a and M are suitable positive integers having 80 decimal digits.

  12. Acoustic properties of NaBi(MoO4)2 crystals

    International Nuclear Information System (INIS)

    Antonenko, A.M.; Stolpakova, T.M.

    1984-01-01

    A complete set of elastic moduli of NaBi(MoO 4 ) 2 monocrystals with the scheelite type structure is measured. Angular dependences of the elastic wave velocities in the plane perpendicular to the fourth order axis are calculated as well as polarization of the propagating sound wave. Directions of pure modes make up angles of 18.1 and 63.1 deg with the [100] axis of the mentioned crystal. Angles of the ultrasonic beam deflection from the wave normal in the NaBi(MoO 4 ) 2 crystal are determined. Comparison is made of elastic properties of NaBi(MoO 4 ) 2 and other crystals having of the scheelite type structure

  13. Mechanical spectra of glass-forming liquids. I. Low-frequency bulk and shear moduli of DC704 and 5-PPE measured by piezoceramic transducers

    DEFF Research Database (Denmark)

    Hecksher, Tina; Olsen, Niels Boye; Nelson, Keith Adam

    2013-01-01

    We present dynamic shear and bulk modulus measurements of supercooled tetraphenyl-tetramethyl-trisiloxane (DC704) and 5-phenyl-4-ether over a range of temperatures close to their glass transition. The data are analyzed and compared in terms of time-temperature superposition (TTS), the relaxation...... is constant over the temperature range explored here. In addition, we demonstrate how one can measure reliably the DC shear viscosity over ten orders of magnitude by using the two measuring techniques in combination....... time, and the spectral shape parameters. We conclude that TTS is obeyed to a good approximation for both the bulk and shear moduli. The loss-peak shapes are nearly identical, while the shear modulus relaxes faster than the bulk modulus. The temperature dependence of this decoupling of time scales...

  14. Elastic moduli, damping and modulus of rupture changes in a high alumina refractory castable due to different types of thermal shock

    Directory of Open Access Journals (Sweden)

    Pereira, A. H. A.

    2012-06-01

    Full Text Available The work herein verifies the changes of the elastic moduli, damping and modulus of rupture (MOR of a high alumina refractory castable due to heating, cooling and heating-cooling thermal shock damage. Twelve prismatic specimens were prepared for the tests and divided into four groups. The thermal shocks were performed on three groups, each containing three specimens having abrupt temperature changes of 1100°C during heating in the first group, during cooling in the second and during heating followed by cooling in the third group. The fourth group, which was taken as a reference did not receive any thermal shock. The elastic moduli were measured after each thermal shock cycle. After 10 cycles, the MOR, the damping and the damping dependence on excitation amplitude were measured at room temperature for all specimens. The elastic moduli showed a similar decrease and the damping a similar increase due to the cooling and heating-cooling thermal shocks. The heating thermal shocks caused no significant changes on the elastic moduli and damping. However, the MOR appeared to be sensitive to the heating thermal shock. This work also shows that the damping for the studied refractory castable is non-linear (i.e., amplitude of excitation sensitive and that this non-linearity increases when the damage level rises.

    En este trabajo se investigaron las alteraciones de los módulos elásticos dinámicos, del amortiguamiento y del módulo de rotura (MOR de un material refractario moldeable de alta alúmina después de recibir choques térmicos de calentamiento, enfriamiento y calentamiento seguido de enfriamiento (calentamiento-enfriamiento. Para ello se prepararon doce cuerpos prismáticos dividiéndolos en cuatro grupos. Los choques térmicos se le aplicaron a sólo tres grupos, cada uno con tres muestras. Al primer grupo se le aplicó un cambio brusco de temperatura de 1100 °C en calentamiento, en enfriamiento al segundo grupo y calentamiento seguido

  15. Theoretical prediction of the fundamental properties for the ternary Li2PtH6 and Na2PtH6

    International Nuclear Information System (INIS)

    Ghebouli, M.A.; Choutri, H.; Bouarissa, N.; Ghebouli, B.; Bouhemadou, A.; Soyalp, F.; Uçgun, E.; Ocak, H.Y.

    2012-01-01

    Li 2 PtH 6 and Na 2 PtH 6 are good candidate for hydrogen storage. The structural, elastic, electronic and optical properties of Li 2 PtH 6 and Na 2 PtH 6 compounds have been investigated using pseudo-potential plane–wave method based on the density functional theory. Computed lattice constant and H atom positional parameter at equilibrium agree well with the available experimental data. A quadratic pressure dependence of the elastic stiffness is found. A set of isotropic elastic parameters and related properties, namely bulk and shear moduli, Young's modulus, Poisson's ratio, average sound velocity and Debye temperature are numerically estimated in the framework of the Voigt–Reuss–Hill approximation for Li 2 PtH 6 and Na 2 PtH 6 polycrystalline aggregate. The analyses of the band structure indicates that Li 2 PtH 6 and Na 2 PtH 6 are indirect gap semiconductors. The static dielectric constant and static refractive index are inversely proportional to the fundamental gap. Highlights: ► We predict elastic moduli, energy gaps and optical parameters. ► Electron effective mass is anisotropic. ► Li 2 PtH 6 and Na 2 PtH 6 are indirect gap semiconductors. ► The contribution to the optical spectra from main transitions are predicted.

  16. On moduli space of symmetric orthogonal matrices and exclusive Racah matrix S bar for representation R = [3,1] with multiplicities

    Science.gov (United States)

    Morozov, A.

    2017-03-01

    Racah matrices and higher j-symbols are used in description of braiding properties of conformal blocks and in construction of knot polynomials. However, in complicated cases the logic is actually inverted: they are much better deduced from these applications than from the basic representation theory. Following the recent proposal of [1] we obtain the exclusive Racah matrix S bar for the currently-front-line case of representation R = [ 3 , 1 ] with non-trivial multiplicities, where it is actually operator-valued, i.e. depends on the choice of bases in the intertwiner spaces. Effective field theory for arborescent knots in this case possesses gauge invariance, which is not yet properly described and understood. Because of this lack of knowledge a big part (about a half) of S bar needs to be reconstructed from orthogonality conditions. Therefore we discuss the abundance of symmetric orthogonal matrices, to which S bar belongs, and explain that dimension of their moduli space is also about a half of that for the ordinary orthogonal matrices. Thus the knowledge approximately matches the freedom and this explains why the method can work - with some limited addition of educated guesses. A similar calculation for R = [ r , 1 ] for r > 3 should also be doable.

  17. Compressive elastic moduli and polishing performance of non-rigid core/shell structured PS/SiO2 composite abrasives evaluated by AFM

    International Nuclear Information System (INIS)

    Chen, Ailian; Mu, Weibin; Chen, Yang

    2014-01-01

    The core/shell structured polystyrene (PS)/SiO 2 composite microspheres with different silica shell morphology were synthesized by a modified Stöber method. As confirmed by transmission electron microscopy (TEM), the rough discontinuous shell consisted of separate SiO 2 nanoparticles for composite-A, while the smooth continuous one was composed of amorphous silica network for composite-B. Atomic force microscopy (AFM) was employed to probe the compressive Young's moduli (E) and chemical mechanical polishing (CMP) performances of the as-prepared PS/SiO 2 composite microspheres. On the basis of the Hertzian contact mechanics, the calculated E values of the PS microspheres, composite-A and composite-B were 2.9 ± 0.4, 5.1 ± 1.2 and 6.0 ± 1.2 GPa, respectively. Compared to traditional abrasives, thermally grown silicon oxide wafers after polished by the core/shell PS/SiO 2 composite abrasives obtained a lower root mean square roughness and a higher material removal rate value. In addition, there is an obvious effect of shell morphology of the composites on oxide CMP performance and structural stability during polishing process. This approach would provide a basis for understanding the actual role of organic/inorganic core/shell composite abrasives in the material removal process of CMP.

  18. Elasticity moduli dependences on the magnetic field of Fe73.5Cu1Nb3Si13.5B9 strips annealed in the range from 300 to 600 C

    International Nuclear Information System (INIS)

    Kaczkowski, Z.; Vlasak, G.; Duhaj, P.

    1996-01-01

    The magnetic field dependences of the elasticity moduli of Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 strips annealed in vacuum for 1 h at 300-600 C were investigated. The maximum changes (ΔE effect), from 60 to 170 GPa, were observed after annealing at 450 C. After annealing at 550 C these changes were from 180 to 210 GPa. The changes are associated with magnetomechanical coupling. (orig.)

  19. Muscle Shear Moduli Changes and Frequency of Alternate Muscle Activity of Plantar Flexor Synergists Induced by Prolonged Low-Level Contraction

    Directory of Open Access Journals (Sweden)

    Ryota Akagi

    2017-09-01

    Full Text Available During prolonged low-level contractions, synergist muscles are activated in an alternating pattern of activity and silence called as alternate muscle activity. Resting muscle stiffness is considered to increase due to muscle fatigue. Thus, we investigated whether the difference in the extent of fatigue of each plantar flexor synergist corresponded to the difference in the frequency of alternate muscle activity between the synergists using muscle shear modulus as an index of muscle stiffness. Nineteen young men voluntarily participated in this study. The shear moduli of the resting medial and lateral gastrocnemius muscles (MG and LG and soleus muscle (SOL were measured using shear wave ultrasound elastography before and after a 1-h sustained contraction at 10% peak torque during maximal voluntary contraction of isometric plantar flexion. One subject did not accomplish the task and the alternate muscle activity for MG was not found in 2 subjects; therefore, data for 16 subjects were used for further analyses. The magnitude of muscle activation during the fatiguing task was similar in MG and SOL. The percent change in shear modulus before and after the fatiguing task (MG: 16.7 ± 12.0%, SOL: −4.1 ± 13.9%; mean ± standard deviation and the alternate muscle activity during the fatiguing task (MG: 33 [20–51] times, SOL: 30 [17–36] times; median [25th–75th percentile] were significantly higher in MG than in SOL. The contraction-induced change in shear modulus (7.4 ± 20.3% and the alternate muscle activity (37 [20–45] times of LG with the lowest magnitude of muscle activation during the fatiguing task among the plantar flexors were not significantly different from those of the other muscles. These results suggest that the degree of increase in muscle shear modulus induced by prolonged contraction corresponds to the frequency of alternate muscle activity between MG and SOL during prolonged contraction. Thus, it is likely that, compared with

  20. A serendipidade na medicina e na anestesiologia

    OpenAIRE

    Vale, Nilton Bezerra do; Delfino, José; Vale, Lúcio Flávio Bezerra do

    2005-01-01

    JUSTIFICATIVA E OBJETIVOS: Neste trabalho foram examinados mais de uma centena dos mais felizes acoplamentos de uma mente brilhante com a sorte benfazeja (serendipidade), através da releitura das mais relevantes histórias sobre invenções e descobertas relacionadas à ciência (n = 46), à Medicina (n = 46) e à Anestesiologia (n = 16). CONTEÚDO: Conceito de serendipidade; exemplos célebres de serendipidade em Ciência e Tecnologia; serendipidade na pesquisa e prática médicas; serendipidade na Anes...

  1. Effect of increasing concentration of Na2O on structural, elastic and optical properties of (90  ‑  x)GeO2–xNa2O–10PbO glass system in the germanate anomaly region

    Science.gov (United States)

    Zainudin, C. N.; Hisam, R.; Yusof, M. I. M.; Yahya, A. K.; Halimah, M. K.

    2017-10-01

    Ternary germanate glasses (90  ‑  x)GeO2–xNa2O–10PbO (x  =  10–30 mol%) have been prepared by the melt-quenching method. Density, ρ increased with Na2O content up to maxima at 20 mol% while molar volume, V a showed an opposite trend to the density, with a minima at 20 mol% of Na2O content indicating the presence of the germanate anomaly. Ultrasonic velocity measurements showed both longitudinal, v l and shear, v s velocities increased up to 20 mol% before decreasing with further addition of Na2O. Independent longitudinal, L and shear, G moduli along with Young’s modulus, Y, mean sound velocity, v m, Debye temperature, θ D, and hardness, H recorded maximum values at 20 mol% of Na2O content which were suggested to be related to the germanate anomaly. Structural modification occurring due to conversion of six-membered GeO4 rings to three-membered rings of GeO4 changed bond density and compactness of the glass systems and caused the increase in rigidity and stiffness of the glasses. Beyond 20 mol% of Na2O, the decrease in the elastic moduli was due to depolymerization of the glass network. Meanwhile, optical energy gap, E opt exhibited a minima at 20 mol% whereas Urbach energy, E U and refractive index, n showed a maxima at the same concentration, thereby indicating variation in polarizability due to changes in concentration of bridging and non-bridging oxygen.

  2. NA60 Status Report

    CERN Document Server

    Usai, G

    2010-01-01

    This report shortly summarizes the main results obtained from the analysis of the NA60 data during 2010, perspectives for the analysis activity during 2011 and the requests to CERN following from them. In addition, renewed interest is expressed for a possible continuation of NA60, including future running at lower SPS energies.

  3. Moduli stabilization, large-volume dS minimum without D3-branes, (non-)supersymmetric black hole attractors and two-parameter Swiss cheese Calabi–Yau’s

    CERN Document Server

    Misra, A

    2008-01-01

    We consider two sets of issues in this paper. The first has to do with moduli stabilization, existence of “area codes” [A. Giryavets, New attractors and area codes, JHEP 0603 (2006) 020, hep-th/0511215] and the possibility of getting a non-supersymmetric dS minimum without the addition of -branes as in KKLT for type II flux compactifications. The second has to do with the “inverse problem” [K. Saraikin, C. Vafa, Non-supersymmetric black holes and topological strings, hep-th/0703214] and “fake superpotentials” [A. Ceresole, G. Dall'Agata, Flow equations for non-BPS extremal black holes, JHEP 0703 (2007) 110, hep-th/0702088] for extremal (non-)supersymmetric black holes in type II compactifications. We use (orientifold of) a “Swiss cheese” Calabi–Yau [J.P. Conlon, F. Quevedo, K. Suruliz, Large-volume flux compactifications: Moduli spectrum and D3/D7 soft supersymmetry breaking, JHEP 0508 (2005) 007, hep-th/0505076] expressed as a degree-18 hypersurface in WCP4[1,1,1,6,9] in the “large-volume...

  4. At NA2

    CERN Multimedia

    1977-01-01

    One of the NA2 calorimeter sections is moved in. The NA2 calorimeter was divided in two halves, to the left and the right of the beam, each half consisting of sheets of passive high Z material interleaved with blades of plastic scintillators. The photo shows on the right, the upstream 'electron' module with eleven lead plates for a total radiation length of 20.

  5. Polarization dependence of Na* + Na* associative ionization revisited

    NARCIS (Netherlands)

    Meijer, H.A.J.; Meulen, H.P. v.d.; Morgenstern, R.; Hertel, I.V.; Meyer, E.; Witte, R.

    1986-01-01

    The dependence of the associative ionization process Na 3 2P3/2 + Na 3 2P3/2 → Na2+ + e- on the polarization of the laser light used for Na excitation was independently investigated in Utrecht and Berlin. The purpose of this paper is to clarify discrepancies between two other earlier experimental

  6. Letramento na contemporaneidade

    OpenAIRE

    Kleiman, Angela B.

    2014-01-01

    Neste trabalho examino a relação entre letramento e contemporaneidade, tomando como base para a discussão o letramento no mundo escolar e sua relação com os letramentos de outras instituições do mundo contemporâneo, a fim de determinar as relações entre as finalidades contemporâneas da leitura e da escrita (em outras palavras, o que significa ser letrado na contemporaneidade) e as práticas mobilizadas e as atividades realizadas na escola para atingir essas finalidades. Através de diversos exe...

  7. Nietzsche na moda

    OpenAIRE

    José,João

    2016-01-01

    Resumo Ao resgatar o filósofo alemão do esquecimento, Stefan Zweig seria o principal responsável pela atual "voga Nietzsche". A edição brasileira de seu livro em 1931 e o artigo "L'actualité de Nietzsche", publicado anonimamente na França em 1933, atestariam o crescente interesse pelo autor de Zaratustra . A presença de Nietzsche na cena contemporânea, todavia, dever-se-ia não somente aos ensaios de outros estudiosos como Salomé (1893), Bertram (1918), Andler (1920) e Walz (1932), mas a um fe...

  8. Riso na epilepsia

    Directory of Open Access Journals (Sweden)

    Edymar Jardim

    1967-06-01

    Full Text Available São estudados três casos de síndrome convulsiva temporal, com manifestações concomitantes de riso na sua fase inicial. As características principais foram a imotivação e á incoercibilidade do riso. Esses sintomas desapareceram com o uso de anticonvulsivantes.

  9. Biotecnologia na agricultura

    Directory of Open Access Journals (Sweden)

    Helaine Carrer

    2010-01-01

    Full Text Available A expectativa de o crescimento populacional atingir 9 bilhões de habitantes em 2050 em adição às questões da sustentabilidade e do aquecimento global nos desafiam a aumentar a oferta de alimentos. Uma metodologia alternativa que contribua para a redução do impacto desse cenário envolve a biotecnologia, que, nas últimas décadas, trouxe marcantes oportunidades tecnológicas na agricultura, resultando em relevante desenvolvimento na obtenção de novas variedades de plantas, na melhoria da qualidade de diversos alimentos e atualmente também na bioenergia. As técnicas biotecnológicas envolvendo os marcadores moleculares, a genômica e a transformação genética estão transformando a agricultura e são discutidas neste artigo.The expected population growth to reach 9 billion by 2050 in addition to issues of sustainability and global warming challenges us to increase the supply of food. An alternative approach to help reducing the impact of this scenario involves biotechnology which in recent decades has brought remarkable technological opportunities in the agriculture that resulted in relevant development in obtaining new plant varieties, improved quality of different foods, and now also in bioenergy. The biotechnology techniques involving molecular markers, genomics and genetic transformation are transforming agriculture and will be discussed in this article.

  10. Hidroma subdural na fossa posterior

    Directory of Open Access Journals (Sweden)

    José Carlos Vasques

    1970-03-01

    Full Text Available Os autores relatam um caso de hidroma subdural na fossa craniana posterior conseqüente a traumatismo na região occipital. O paciente foi operado com pleno sucesso. A raridade da localização de hidroma na fossa posterior é salientada, sendo discutidos os possíveis mecanismos etio-patogênicos.

  11. A epilepsia na neurocisticercose

    Directory of Open Access Journals (Sweden)

    Luís Marques-Assis

    1972-12-01

    Full Text Available Foram estudados 131 casos de epilepsia com etiologia cisticercótica comprovada. A idade variou de 2 a 68 anos; 75 pacientes eram de sexo masculino e 56 de sexo feminino; 117 eram brancos, 10 pardos, três pretos e um amarelo. A idade de início da doença predominou na primeira década. O estudo foi feito em relação ao tipo de epilepsia, ao tempo decorrido após a primeira crise, à freqüência das crises e ao eletrencefalograma relativamente às epilepsias em geral. Investigação foi feita também em relação à cefaléia, aos achados neurológicos, liquóricos, radiológicos simples e contrastados e anátomo-patológicos. A análise dos resultados permitiu aos autores as seguintes conclusões: 1 No grupo de neurocisticercose o início da doença predominou na primeira e a partir da quarta década em relação às epilepsias em geral. 2 Dentre as manifestações clínicas predominaram as formas convulsivas da doença (61%, sendo as crises bravas-jacksonianas as menos freqüentes (4%; quando comparadas com as epilepsias em geral, verifica-se incidência menor das convulsões generalizadas na neurocisticercose. 3 Quanto ao tempo de doença, verifica-se predomínio das formas de duração mais curta (um ano ou menos na neurocisticercose. 4 A severidade da epilepsia, traduzida pela freqüência das crises, foi menor no grupo com neurocisticercose. 5 Excluídos os casos com anormalidades eletrencefalográficas contínuas, foram encontrados maiores índices percentuais de EEG normal na neurocisticercose que nas epilepsias em geral. 6 A cefaléia estava presente em 68% dos casos, assumindo caráter paroxístico na maior parte (78%; em 67% dos casos com cefaléia paroxística não havia concomitantemente sinais de hipertensão intracraniana; nos casos com cefaléia contínua, em apenas dois (13% esses sinais não estavam presentes. 7 Na maior parte dos casos (62% as manifestações epilépticas se apresentaram isoladamente, sem sinais neurol

  12. The CERES / NA45 experiment

    CERN Multimedia

    Laurent Guiraud

    2000-01-01

    Ceres is one of the second generation heavy ion experiments at CERN's SPS. It is dedicated to the study of electron-positron pairs in relativistic nuclear collisions. NA45 is one of the seven experiments (NA44, NA45, NA49, NA50, NA52, WA97/NA57 and WA98) involved in CERN's Heavy Ion programme which provided evidence for the existence of a new state of matter, the quark-gluon plasma. In this state, quarks, instead of being bound up into more complex particles such as protons and neutrons, are liberated and roam freely. Theory predicts that this state must have existed at about 10 microseconds after the Big Bang, before the formation of matter as we know it today.

  13. Investigation of chemical bond characteristics, thermal expansion coefficients and bulk moduli of alpha-R2MoO6 and R2Mo2O7 (R = rare earths) by using a dielectric chemical bond method.

    Science.gov (United States)

    Li, Huaiyong; Zhang, Siyuan; Zhou, Shihong; Cao, Xueqiang

    2009-09-01

    Theoretical researches are performed on the alpha-R2MoO6 (R = Y, Gd, Tb Dy, Ho, Er, Tm and Yb) and pyrochlore-type R2Mo2O7 (R = Y, Nd, Sm, Gd, Tb and Dy) rare earth molybdates by using chemical bond theory of dielectric description. The chemical bonding characteristics and their relationship with thermal expansion property and compressibility are explored. The calculated values of linear thermal expansion coefficient (LTEC) and bulk modulus agree well with the available experimental values. The calculations reveal that the LTECs and the bulk moduli do have linear relationship with the ionic radii of the lanthanides: the LTEC decreases from 6.80 to 6.62 10(-6)/K and the bulk modulus increases from 141 to 154 GPa when R goes in the order Gd, Tb Dy, Ho, Er, Tm, and Yb in the alpha-R2MoO6 series; while in the R2Mo2O7 series, the LTEC ranges from 6.80 to 6.61 10(-6)/K and the bulk modulus ranges from 147 to 163 GPa when R varies in the order Nd, Sm, Gd, Tb and Dy. Copyright 2008 Wiley Periodicals, Inc.

  14. na Perua

    Directory of Open Access Journals (Sweden)

    Jorge Carvalho

    1989-01-01

    Full Text Available Antes de se caracterizar como tentativa de ensaio ou de análise a qualquer coisa, o presente artigo tem, antes de mais nada, a pretensão de se constituir uma provocação ao debate acerca da questão do esporte na escola. A provocação parte basicamente do relato da minha experiência pessoal como Secretário da Educação do Município de Aracaju, cargo que exerci no período de 1º de janeiro de 1986 a 27 de janeiro de 1987.

  15. Envolvimento pulmonar na polimiosite

    Directory of Open Access Journals (Sweden)

    Direndra Hasmucrai

    2010-07-01

    Full Text Available Resumo: Introdução: A polimiosite (PM e a dermatomiosite são classificadas como miopatias inflamatórias idiopáticas. O envolvimento pulmonar por PM é pouco frequente, estando descrito na literatura em cerca de 10% de casos.Os autores apresentam um caso de uma mulher de 75 anos, com queixas de febre, perda ponderal, artralgias, mialgias e diminuição simétrica e proximal da força muscular com impotência funcional dos membros superiores e inferiores, com início um mês antes do internamento. Apresentava infiltrados pulmonares na telerradiografia de tórax. Após estudo exaustivo estabeleceu-se o diagnóstico de envolvimento pulmonar na forma de pneumonia organizativa por PM. Efectuou-se corticoterapia e terapêutica com micofenolato com melhoria clínica, analítica e radiológica.Conclusão: Neste caso, foi a alteração na telerradiografia de tórax numa doente sem sintomatologia respiratória que levou ao estudo exaustivo até ao diagnóstico de PM, realçando mais uma vez a importância da telerradiografia no rastreio de patologias de outros foros.Rev Port Pneumol 2010; XVI (4: 671-677 Abstract: Introduction: Polymyositis and dermatomyositis are classified as idiopathic inflammatory myopathies. Interstitial lung disease is rare and is described in the literature in about 10% of cases.The authors describes a case of 75 year old woman presenting with one month evolution of fever, weight loss, arthralgia, myalgia and symmetric and proximal muscle weakness of upper and lower limbs. Nonspecific interstitial changes was found in chest X-ray. After exhaustive study, the diagnosis of pulmonary envolvement in the form of organizing pneumonia by polymyositis, was established. Glucocorticoids and mycophenolate were prescribed with good clinical, analytical and radiological outcome.Conclusion: In this case, it was the changes in the chest X-ray in a patient without respiratory sym ptomatology, that conducted to exhaustive study to polymyositis

  16. Envolvimento pulmonar na polimiosite

    Directory of Open Access Journals (Sweden)

    Direndra Hasmucrai

    2010-07-01

    Full Text Available Resumo: Introdução: A polimiosite (PM e a dermatomiosite são classificadas como miopatias inflamatórias idiopáticas. O envolvimento pulmonar por PM é pouco frequente, estando descrito na literatura em cerca de 10% de casos.Os autores apresentam um caso de uma mulher de 75 anos, com queixas de febre, perda ponderal, artralgias, mialgias e diminuição simétrica e proximal da força muscular com impotência funcional dos membros superiores e inferiores, com início um mês antes do internamento. Apresentava infiltrados pulmonares na telerradiografia de tórax. Após estudo exaustivo estabeleceu-se o diagnóstico de envolvimento pulmonar na forma de pneumonia organizativa por PM. Efectuou-se corticoterapia e terapêutica com micofenolato com melhoria clínica, analítica e radiológica. Conclusão: Neste caso, foi a alteração na telerradiografia de tórax numa doente sem sintomatologia respiratória que levou ao estudo exaustivo até ao diagnóstico de PM, realçando mais uma vez a importância da telerradiografia no rastreio de patologias de outros foros. Abstract: Introduction: Polymyositis and dermatomyositis are classified as idiopathic inflammatory myopathies. Interstitial lung disease is rare and is described in the literature in about 10% of cases.The authors describes a case of 75 year old woman presenting with one month evolution of fever, weight loss, arthralgia, myalgia and symmetric and proximal muscle weakness of upper and lower limbs. Nonspecific interstitial changes was found in chest X-ray. After exhaustive study, the diagnosis of pulmonary envolvement in the form of organizing pneumonia by polymyositis, was established. Glucocorticoids and mycophenolate were prescribed with good clinical, analytical and radiological outcome. Conclusion: In this case, it was the changes in the chest X-ray in a patient without respiratory symptomatology, that conducted to exhaustive study to polymyositis diagnosis, enhancing once again the

  17. Ultrasonic, FTIR and thermal investigations of SiO2-Na2O-CaO-P2O5 glasses doped with CeO2

    Science.gov (United States)

    Marzouk, Samir Y.

    2010-11-01

    The longitudinal and shear ultrasonic wave velocities for different compositions of SiO2-Na2O-CaO-P2O5 glasses were measured at room temperature (305 K) using a pulse-echo method at a frequency of 4 MHz. The elastic moduli, Poisson's ratio, microhardness, Debye temperature and other ultrasonic parameters were obtained from experimental data and analyzed using bond compression theory. By calculating the number of network bonds per unit volume, the average stretching constant, and the average ring size, information about the structure of the glass can be deduced. Structural changes after doping with CeO2 were investigated by FTIR spectroscopy, and by measurements of the thermal expansion coefficient, glass transition and softening temperature to throw more light on the characterization of these glasses.

  18. Theoretical prediction of the fundamental properties for the ternary Li2PtH6 and Na2PtH6

    Science.gov (United States)

    Ghebouli, M. A.; Choutri, H.; Bouarissa, N.; Ghebouli, B.; Bouhemadou, A.; Soyalp, F.; Uçgun, E.; Ocak, H. Y.

    2012-12-01

    Li2PtH6 and Na2PtH6 are good candidate for hydrogen storage. The structural, elastic, electronic and optical properties of Li2PtH6 and Na2PtH6 compounds have been investigated using pseudo-potential plane-wave method based on the density functional theory. Computed lattice constant and H atom positional parameter at equilibrium agree well with the available experimental data. A quadratic pressure dependence of the elastic stiffness is found. A set of isotropic elastic parameters and related properties, namely bulk and shear moduli, Young's modulus, Poisson's ratio, average sound velocity and Debye temperature are numerically estimated in the framework of the Voigt-Reuss-Hill approximation for Li2PtH6 and Na2PtH6 polycrystalline aggregate. The analyses of the band structure indicates that Li2PtH6 and Na2PtH6 are indirect gap semiconductors. The static dielectric constant and static refractive index are inversely proportional to the fundamental gap.

  19. Comprometimento pulmonar na leptospirose

    Directory of Open Access Journals (Sweden)

    Jorge Eduardo Manhães de Carvalho

    1992-03-01

    Full Text Available Em 23 pacientes com leptospirose apresentando comprometimento pulmonar, internados no Hospital Universitário Antônio Pedro da XJFF, Niterói, hemoptise e hemoptóicos foram observados em 21,7% e 30,4%, respectivajnente. Gasometria arterial revelou hipoxemia e hipocapnia na maioria dos casos. Radiografia de tórax em 15 pacientes mostrou comprometimento alveolar em 60%, comprometimento intersticial-reticular em 6%, padrão misto (alveolar e intersticial em20%e ausência de alterações radiológicas em 14%. A necrópsiade 13 pacientes mostrou edema, congestão e hemorragia nos pulmões em 100% dos casos. A hemorragia foi focal em 46% e difusa em 54% dos casos. Houve formação de membrana hialina em 30% e trombos de fibrina em 46% dos pulmões estudados, o que estabelece o diagnóstico da coagulação intravascular disseminada e a ocorrência da síndrome de angústia respiratória na leptospirose.

  20. ANALIZA POSLOVNE KULTURE NA JAPONSKEM

    OpenAIRE

    Ocvirk, Katja

    2012-01-01

    Poslovanje na mednarodnih trgih se z globalizacijo vedno bolj spreminja. V delu diplomskega seminarja sem opredelila kulturo in opisala njene pomembne sestavine ter značilnosti. Spoznala sem, da mora biti poslovnež, ki deluje na mednarodnem trgu, zelo dobro pripravljen in seznanjen s kulturnimi razlikami, da se izogne nepotrebnim napakam in spodrsljajem. Menim, da moramo pri poslovanju s poslovnimi partnerji, ki prihajajo iz drugih kultur, vedeti, kako deluje njihovo poslovno okolje. Na ...

  1. NA48 prototype calorimeter

    CERN Multimedia

    1990-01-01

    This is a calorimeter, a detector which measures the energy of particles. When in use, it is filled with liquid krypton at -152°C. Electrons and photons passing through interact with the krypton, creating a shower of charged particles which are collected on the copper ribbons. The ribbons are aligned to an accuracy of a tenth of a millimetre. The folding at each end allows them to be kept absolutely flat. Each shower of particles also creates a signal in scintillating material embedded in the support disks. These flashes of light are transmitted to electronics by the optical fibres along the side of the detector. They give the time at which the interaction occurred. The photo shows the calorimeter at NA48, a CERN experiment which is trying to understand the lack of anti-matter in the Universe today.

  2. Na Cauda do Cometa

    Science.gov (United States)

    Voelzke, M. R.

    2009-01-01

    Quando viam um cometa, os antigos gregos imaginavam uma estrela com uma vasta cabeleira. Não à toa, a palavra deriva do termo koma, que significa cabelo. Constituídos por fragmentos de gelo e gases, os cometas possuem um núcleo sólido, que pode ter vários quilômetros de diâmetro, e uma cauda que sempre aponta na direção contrária ao Sol, devido aos ventos solares. Graças à aparência de pontos luminosos em movimento (ao contrário de outros astros, que parecem estáticos), esses corpos celestes foram interpretados por diferentes povos com muito misticismo, inspirando mitos tanto de boas-novas como de maus presságios. Conheça algumas dessas histórias:

  3. A ENGENHARIA NA ESCOLA

    Directory of Open Access Journals (Sweden)

    Valéria Pelizzer Casara

    2015-04-01

    Full Text Available Este projeto teve por objetivo principal mostrar às jovens do ensino médio, como as áreas de exatas e de engenharia podem estar inseridas em situações rotineiras por elas vivenciadas e incentivá-las para ingressarem nessas áreas. O projeto foi executado na escola de ensino Médio Nelson Horostecki na cidade de Chapecó, Santa Catarina. Mostrou-se de forma simples que as áreas de exatas e de engenharia têm aplicações práticas nas nossas vidas. No desenvolvimento do projeto, realizaram-se oficinas na escola cujo tema principal abordado foi o processo de fabricação do chocolate, visto que o mesmo é um produto muito apreciado pelas adolescentes. Dentro dessa temática, foram trabalhadas as questões que envolvem conhecimentos das áreas de exatas e de engenharia, mais especificamente a Engenharia Ambiental. O projeto auxiliou na formação cidadã e também na escolha profissional das meninas. Muitas das alunas participantes nunca haviam tido contato direto com alunos graduandos de cursos na área das exatas. Mais ainda, este projeto oportunizou a aproximação da universidade com a comunidade externa. Palavras-chave: Extensão Universitária, Ciências Exatas e Engenharia, Chocolate, Oficinas.   Engineering in the school Abstract: The main objective of this project was to show high school female students how the exact sciences and engineering can be included in their routine situations encouraging them to entering in these areas. The project was carried out at the Nelson Horostecki High School in Chapecó, Santa Catarina State, Brazil. It was showed in a simple manner how exact sciences and engineering have practical applications in our lives. Workshops were conducted in the school during the execution of the project in which the main subject was the chocolate manufacturing process, since chocolate is a product greatly appreciated by the young female people. Within this matter, the activities were performed using the knowledge of

  4. Electronic properties and bulk moduli of new boron nitride polymorphs, i.e., hyperdiamond B12N12 and simple cubic B24N24, B12N12 fulborenites

    International Nuclear Information System (INIS)

    Pokropivny, V. V.; Bekenev, V. L.

    2006-01-01

    The energy-band structure, density of states, electron density distribution, equation of state, and bulk moduli of three boron-nitride fulborenite crystals, i.e., B 12 N 12 with diamond lattice and B 24 N 24 , B 12 N 12 with simple cubic lattice, whose sites contain fulborene B 12 N 12 and B 24 N 24 molecules, are calculated for the first time using the full-potential linearized augmented plane wave method. The following hyperdiamond B 12 N 12 parameters were obtained: the equilibrium lattice parameter a = 1.1191 nm, the B-N bond length a BN = 0.1405 nm, the number of atoms per unit cell Z = 192, the density ρ = 2.823 g/cm 3 , the bulk modulus B 0 = 658 GPa, and the band gap ΔE g = 3.05 eV. This is a previously unknown unique light superhard semiconductor faujasite with a recorded bulk modulus higher than that of diamond. There are reasons to assume that it is a E phase. The characteristics of B 24 N 24 with simple cubic lattice are as follows: the equilibrium lattice parameter a = 0.7346 nm, the B-N bond length a BN = 0.1521 nm, the number of atoms per unit cell Z = 48, the density ρ = 2.495 g/cm 3 , the bulk modulus B 0 = 367 GPa, and the band gap ΔE g = 3.76 eV. This material is a heteropolar semiconductor or insulator with a bulk modulus comparable with that of cubic boron nitride, as well as a new boron-nitride zeolite with channel diameter of 0.46 nm. B 12 N 12 with simple cubic lattice is a molecular semimetal

  5. Hodler à Iéna

    OpenAIRE

    2017-01-01

    A la mort de Hodler, on demanda que les planches qui recouvrait la fresque de Iéna, depuis la protestation contre le bombardement de Reims, soit enlevées. Les autorités de Iéna ont refusé énergiquement.

  6. Valores na escola

    Directory of Open Access Journals (Sweden)

    Menin Maria Suzana De Stefano

    2002-01-01

    Full Text Available Neste texto pretende-se discorrer sobre valores morais na escola e suas implicações para a formação de professores. Para tanto discutir-se-á, em primeiro lugar, e brevemente, o que são valores morais, ou éticos, e como a escola pode situar-se em relação a eles. Em seguida, serão relatadas algumas observações a respeito de valores de professores e práticas daí decorrentes. São comentados resultados de pesquisa que ilustram a transmissão de valores de forma doutrinal e a educação moral e cívica tal como realizada na ditadura militar, e, por outro lado, a posição relativista e/ou de laissez-faire que certas escolas podem adotar, metodologicamente, sobre a educação em valores. Finalmente, defender-se-á a idéia de que é necessária uma discussão sobre valores pelos diversos membros da escola e uma opção por uma metodologia para ensiná-los, seja os professores, em sua formação inicial e continuada, seja os alunos. A teoria de desenvolvimento moral de Jean Piaget será apresentada como uma referência possível para a educação em valores. Exemplos de situações escolares de conflito de valores entre direção, pais e alunos são discutidas para ilustrar como uma escola pode adotar um procedimento democrático de educação em valores, que se apresenta como um terceiro caminho possível de educação moral nas escolas, além das posições doutrinárias ou relativistas.

  7. Poklicna izgorelost ali zavzetost za delo, to je zdaj vprašanje Osebni in skupinski izobraževalni moduli za preprečevanje poklicne izgorelosti (2. del

    Directory of Open Access Journals (Sweden)

    Andreja Pšeničny

    2005-12-01

    Full Text Available Raziskavo sta avtorici posvetili preucevanju potreb po varovanju zaposlenih pred poklicno izgorelostjo, hkrati pa tudi spodbujanju njihove zavzetosti za delo. Podjetje, ki se zaveda pomena svojih virov, lahko v enem in drugem primeru s podobnimi izobrazevalnimi vsebinami in postopki oplemeniti svoj najpomembnejsi vir ljudi. Avtorici ugotavljata, da v zvezi s poklicno izgorelostjo danes ni vec poudarek na preucevanju osebnostnih lastnosti za delo »preveč« vnetih ljudi, marvec predvsem na proucevanju delovnega okolja in psiholoških delovnih okolisCin v podjetju. Poklicno izgorelost lahko prepreCimo tudi z znanstveno utemeljeno organiziranostjo podjetja ali ustanove; taksno, ki spodbuja formalne in neformalne komunikacijske okoliscine, pozitivne medsebojne in kolektivne odnose ter druge ugodne psihološke delovne okoliscine. Izobrazevanje za prepoznavanje in preprečevanje poklicne izgorelosti na eni strani ter izobrazevanje za spodbujanje zavzetosti za delo na drugi strani je posvečeno posameznikom, podjetjem, strokovni in široki javnosti.

  8. A aposta na filosofia

    Directory of Open Access Journals (Sweden)

    Márcio Suzuki

    2011-12-01

    Full Text Available Para Hume, filosofar é uma atividade semelhante às demais ocupações humanas. A decisão que leva à atividade filosófica é menos resultado de uma argumentação teórica do que fruto de um cálculo prático, que é entendido como uma caça ou um jogo. O objetivo deste trabalho será o de mostrar que no jogo filosófico perde quem joga sério demais. A aposta na filosofia tem que passar pelo bom humor e pela diversão: uma resposta a Pascal?For Hume, philosophy is in itself neither more nor less important than other human activities. On the contrary, it can be explained from its resemblance with game and hunting. If one chooses to dedicate himself to philosophy, his decision is not the consequence of logical reasoning, but depends on practical evaluation, which has something to do with gambling. The following text tries to show that in philosophy, like in other games, the loser will be the one who plays too earnestly. The philosophical game requires good humour and some relaxation: Is this a good answer to Pascal's pari?

  9. A Arquitetura na Cidade

    Directory of Open Access Journals (Sweden)

    Euler Sandeville Junior

    2013-07-01

    Full Text Available Este artigo é uma reflexão sobre três casos em que a arquitetura define a configuração do espaço público, investigando seus significados e pressupostos. São levantadas questões que não comportam respostas definitivas, mas que induzem a alguns parâmetros para discutir a atuação do arquiteto no espaço público, nas áreas centrais de nossas cidades. Nosso título é, sem dúvida, devedor do célebre trabalho de Aldo Rossi, a Arquitetura da cidade (1966. Porém, nos ocupamos apenas da inserção da arquitetura na cidade e numa perspectiva teórica muito distinta, reconhecendo para o projeto do objeto arquitetônico uma dependência do espaço e do tempo e das relações sociais que assim se estabelecem. São analisados o Memorial da América Latina, a estação Barra Funda do Metrô e a Praça da Sé. São aqui entendidos como campos de projeto da paisagem e, como tal, problematizados.

  10. O SUBLIME NA MODERNIDADE

    Directory of Open Access Journals (Sweden)

    Martha de Almeida

    2009-03-01

    Full Text Available A obra Uma investigação filosófica sobre a origem de nossas idéias do sublime e dobelo, do sensualista inglês Edmund Burke (1757, data as origens do sublime na Modernidade. Nosublime ocorre é um prazer ligado à dor, um "horror delicioso" que sentimos quando acreditamosque estamos em perigo sem que isso esteja ocorrendo realmente. Em O mundo como Vontade erepresentação Schopenhauer assume as influências que sofreu de Kant no que diz respeito à suainterpretação sobre o belo e o sublime, porém difere dele quanto à natureza dessa impressão. ParaSchopenhauer a experiência estética pressupõe a dissolução da subjetividade num movimento decontemplação das idéias livre do querer imposto pela vontade individual. As idéias deSchopenhauer influenciaram a estética do Nietzsche de O nascimento da tragédia.

  11. Low moduli elastomers with low viscous dissipation

    DEFF Research Database (Denmark)

    Bejenariu, Anca Gabriela; Yu, Liyun; Skov, Anne Ladegaard

    2012-01-01

    A controlled reaction schema for addition curing silicones leads to both significantly lower elastic modulus and lower viscous dissipation than for the chemically identical network prepared by the traditional reaction schema.......A controlled reaction schema for addition curing silicones leads to both significantly lower elastic modulus and lower viscous dissipation than for the chemically identical network prepared by the traditional reaction schema....

  12. Theoretical characterization of quaternary iridium based hydrides NaAeIrH{sub 6} (Ae = Ca, Ba and Sr)

    Energy Technology Data Exchange (ETDEWEB)

    Bouras, S. [Laboratory of Studies Surfaces and Interfaces of Solids Materials, Department of Physics, Faculty of Science, University of Setif 1, 19000 (Algeria); Ghebouli, B., E-mail: bghebouli@yahoo.fr [Laboratory of Studies Surfaces and Interfaces of Solids Materials, Department of Physics, Faculty of Science, University of Setif 1, 19000 (Algeria); Benkerri, M. [Laboratory of Studies Surfaces and Interfaces of Solids Materials, Department of Physics, Faculty of Science, University of Setif 1, 19000 (Algeria); Ghebouli, M.A., E-mail: med.amineghebouli@yahoo.fr [Microelectronic Laboratory (LMSE), University of Bachir Ibrahimi, Bordj-Bou-Arreridj 34000 (Algeria); Research Unit on Emerging Materials (RUEM), University of Setif 1, 19000 (Algeria); Choutri, H. [Microelectronic Laboratory (LMSE), University of Bachir Ibrahimi, Bordj-Bou-Arreridj 34000 (Algeria); Louail, L.; Chihi, T.; Fatmi, M. [Research Unit on Emerging Materials (RUEM), University of Setif 1, 19000 (Algeria); Bouhemadou, A. [Laboratory for Developing New Materials and Their Characterization, Department of Physics, Faculty of Science, University of Setif 1, 19000 (Algeria); Department of Physics and Astronomy, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Khenata, R.; Khachai, H. [Laboratoire de Physique Quantique et de Modélisation Mathématique, Université de Mascara, 29000 (Algeria)

    2015-01-15

    The quaternary iridium based hydrides NaAeIrH{sub 6} (Ae = Ca, Ba and Sr) are promising candidates as hydrogen storage materials. We have studied the structural, elastic, electronic, optical and thermodynamic properties of NaAeIrH{sub 6} (Ae = Ca, Ba and Sr) within the generalized gradient approximation, the local density approximation (LDA) and mBj in the frame of density functional perturbation theory. These alloys have a large indirect Γ–X band gap. The thermodynamic functions were computed using the phonon density of states. The origin of the possible transitions from valence band to conduction band was illustrated. By using the complex dielectric function, the optical properties such as absorption, reflectivity, loss function, refractive index and optical conductivity have been obtained. - Graphical abstract: Real and imaginary parts of the dielectric function, the absorption spectrum α(ω), reflectivity R(ω) and energy-loss spectrum L(ω). - Highlights: • NaAeIrH{sub 6} (Ae = Ca, Ba and Sr) alloys have been investigated. • The elastic moduli, energy gaps are predicted. • The optical and thermal properties were studied.

  13. DFT Predictions of Electronic, Transport, and Bulk Properties of Cubic Antifluorite A2B Compounds (A = Li, Na, B = O,S,Se)

    Science.gov (United States)

    Malozovsky, Yuriy; Franklin, Lashounda; Bagayoko, Diola

    We present results from ab-initio,self-consistent calculations of electronic, transport, and bulk properties of cubic antifluorite (anti-CaF2) compounds A2B (A = Li, Na, B = O, S, Se). Our computations employed the local density approximation (LDA) potential of Ceperley and Alder and the linear combination of atomic orbital (LCAO) formalism. The implementation of the LCAO formalism followed the Bagayoko, Zhao, and Williams method, as enhanced by Ekuma and Franklin (BZW-EF). Consequently, our calculations search for and attained the ground states of the systems under study, as required by DFT; our results therefore possess the full, physical content of DFT. We discuss band structures, band gaps, and related properties of these materials, including calculated, total and partial densities of states (DOS and PDOS), effective masses of charge carriers, equilibrium lattice constants, and the bulk moduli of cubic antifluorite compounds A2B (A = Li, Na, B = O, S, Se). Our results are predictions in some cases, due to the lack of experimental data. Work funded in part by the US Department of Energy (DOE), National Nuclear Security Administration (NNSA) (Award No.DE-NA0002630), the National Science Foundation (NSF) (Award No, 1503226), LaSPACE, and LONI-SUBR.

  14. SPOLNO NADLEGOVANJE NA DELOVNEM MESTU

    OpenAIRE

    Rubič, Gašper

    2016-01-01

    V diplomskem delu smo v uvodu predstavili problem spolnega nadlegovanja na delovnem mestu in predstavili podjetje TEKSTIL d.d. V nadaljevanju smo z anketo raziskali, ali problem spolnega nadlegovanja na delovnem mestu v obravnavanem podjetju obstaja in če, kako se nanj odziva okolje. V teoretičnem delu smo nadaljevali in predstavili definicijo spolnega nadlegovanja, ki je kakršna koli oblika nezaželenega verbalnega in neverbalnega ali fizičnega ravnanja spolne narave z učinkom ali nameno...

  15. Hemisferectomia na hemiplegia infantil

    Directory of Open Access Journals (Sweden)

    Rolando A. Tenuto

    1956-03-01

    Full Text Available Os autores relatam o caso de um paciente com 18 anos de idade, portador de paralisia cerebral instalada aos 4 anos de idade após moléstia febril prolongada (hemiplegia esquerda, crises convulsivas generalizadas, freqüentes e rebeldes à medicação, deficiência mental e alterações de conduta. O eletrencefalograma e o pneumencefalograma revelaram alterações graves do hemisfério direito; tendo o primeiro destes exames demonstrado a existência de perturbações propagadas ao outro hemisfério. Foi praticada a hemisferectomia direita. Durante o ato cirúrgico, por exigência técnica foram extirpados, além do hemisfério cerebral, os dois terços rostrais do núcleo caudado e o núcleo amigdalóide. No pós-operatório foi intercorrência de osteomielite e meningite, medicadas com antibióticos e seqüestrectomia. Apesar da complicação pós-operatória, instalou-se progressiva melhora em relação à conduta social; diminuiu também a espasticidade no membro inferior esquerdo e não mais se repetiram as crises convulsivas. Não foram observadas modificações quanto ao rendimento intelectual e quanto aos distúrbios sensitivos que existiam antes da intervenção cirúrgica. O exame neurocular mostrou hemianopsia homônima esquerda. Êstes resultados são concordantes com os assinalados na literatura sobre o assunto.

  16. Active transport of Na+ by reconstituted Na,K-ATPase

    International Nuclear Information System (INIS)

    Boldyrev, A.A.; Svinukhova, I.A.

    1987-01-01

    The ability of ATP, CTP, ITP, GTP, and UTP to support ouabain-sensitive accumulation of Na + by proteoliposomes with a reconstituted Na/K-pump was investigated. At a low [Na + ]/[K + ] ratio in the medium (20 mM/50 mM), a correlation is observed between the proton-accepting capacity of the nucleotide and its effectiveness as a substrate of active transport. To test the hypothesis of the importance of the presence of a negative charge in the 1-position of the purine (3-pyrimidine) base of the nucleotide for mutual transitions between the Na- and K-conformations of Na,K-ATPase they used two analogs of ATP: N 1 -hydroxy-ATP, possessing proton acceptor capacity, and N 1 -methoxy-ATP, in the molecule of which the negative charge is quenched by a methyl group. The first substrate supports active accumulation of Na + in proteoliposomes at the same rate as ATP, whereas the second substrate is relatively ineffective

  17. Risbjerg: Historisk stemmeskred med NA

    DEFF Research Database (Denmark)

    Thomsen, Søren Risbjerg

    2007-01-01

    ANALYSE: NA flytter 12,3 pct. af stemmerne i majs meningsmålinger - historisk mange vælgere på en måned, skriver professor Risbjerg. Udgivelsesdato: 3. juni 2007......ANALYSE: NA flytter 12,3 pct. af stemmerne i majs meningsmålinger - historisk mange vælgere på en måned, skriver professor Risbjerg. Udgivelsesdato: 3. juni 2007...

  18. Na via do Behemoth

    Directory of Open Access Journals (Sweden)

    Gérard Rabinovitch

    2008-06-01

    Full Text Available O momento nazista permanece um enigma impensado de que a cultura contemporânea continua cativa. O autor levanta a hipótese de que a persistência desse enigma e seus estragos duráveis se devem à insistência dos pensamentos político, sociológico e filosófico em construírem o nazismo à luz da metáfora hobbesiana do Leviatã. Propõe retomar a questão do nazismo sob a perspectiva do Behemoth, antônimo do Leviatã. Para tanto, sugere a necessidade de retornar a Freud e à psicanálise, balizas de um possível novo pensamento do político que escrutine a destrutividade nazista. Propõe ainda sondar as homologias entre nazismo, corjas e máfias, com base na figura da " heroicização da violência" que lhes seria comum. E avança um modelo " econômico" : a quimera, suscetível de capturar o caráter heterotópico e heterocrônico de sua construção criminosa.The paths of Behemoth. The Nazi moment remains as the thoughtless enigma of which contemporary culture is still captive. The author raises the hypothesis where the persistency of this enigma and its durable damages are due to the insistence of the political, social and philosophical thoughts in building the Nazism at the view of the Hobbesian metaphor of Leviathan. It is here proposed to resume the Nazism matter under Behemoth's perspective, antonym to Leviathan. For such, it is suggested a necessity to look back at Freud and the psychoanalysis, structured by a possible new political thought which scrutinizes the destructivity of the Nazism. It is also here proposed to gaze at the homologies between Nazism, mafias and gangs, with a base in the figure of " violence as a heroically act" that are their common ground. The author also advances an economical model: the chimera susceptible to capture the heterotopic and heterochronic character of its criminal construction.

  19. Estresse ocupacional na enfermagem atuante na unidade de terapia intensiva

    OpenAIRE

    Borges Teixeira, Larissa; Portela Veloso, Lorena Uchôa; Universidade Estadual do Piauí; Pereira Ribeiro, Ítalo Arão; Universidade Estadual do Piauí; Nunes de Oliveira, Tauane; Instituto de Ensino Superior Franciscano; Leal Cortez, Antônio Carlos; Universidade Estadual do Piauí

    2017-01-01

    Introdução: O estresse tem sido um dos problemas que mais tem acometido a equipe de enfermagem dentro da unidade de terapia intensiva (UTI), causando prejuízo funcional, bem como instabilidade na saúde desses profissionais. Objetivo: Descrever, através da revisão integrativa, o estresse no trabalho da enfermagem na UTI, bem como identificar fatores, sinais e sintomas associados ao estresse ocupacional. Método: Trata-se de uma pesquisa integrativa, utilizando como banco de dados a Biblioteca V...

  20. Corpo e sexualidade na gravidez

    Directory of Open Access Journals (Sweden)

    Natalúcia Matos Araújo

    2012-06-01

    Full Text Available Estudo etnográfico que teve como objetivo compreender como as gestantes vivenciam os processos fisiológicos do seu corpo durante a gestação e a sua repercussão na sexualidade. A pesquisa envolveu sete mulheres residentes em bairro popular de São Paulo. Na coleta de dados, utilizou-se observação participante e entrevista com questões norteadoras. Os dados foram apresentados na forma de narrativa e posteriormente organizados nas categorias: Percebendo as transformações corporais; Convivendo com as mudanças no corpo; Sentimentos e sensações na vida sexual durante a gestação e imaginando o corpo e a sexualidade após a gestação. As mulheres referiram-se às transformações do corpo como desconfortos e expressaram a preocupação de que fossem definitivas. Expressaram o desejo de que, após o parto, o corpo volte a ser como era e que volte a sentir desejo sexual. O reconhecimento destes fatos constitui-se numa ferramenta primordial na adequação das práticas profissionais.

  1. All new for NA62

    CERN Multimedia

    Antonella Del Rosso

    2012-01-01

    This week sees the start of the first run of the new NA62 experiment. This will be a unique opportunity for the collaboration to test its new beam, new detectors and new data acquisition system before the physics run in 2014. Speaking to the Bulletin, the NA62 technical coordinator Ferdinand Hahn shares the many challenges that the various teams faced to be on time for beam. Ready, steady, start!   A Large Angle Veto detector (white) in place in the NA62 decay volume (blue). With components from almost all the detectors in place downstream of the decay point of the mother particles – the kaons – and of the KTAG detector that tags the kaons before they decay, NA62 is ready for its first technical run. This unique run will test all the equipment as well as the trigger and the data acquisition systems. “This year, we will have about five weeks of beam from the SPS before the long shutdown of all the CERN machines,” says Ferdinand Hahn, NA62 Technical Co-...

  2. Kostel na Lesné

    OpenAIRE

    Pospíšil, Vojtěch

    2017-01-01

    Tato teoretická diplomová práce se zabývá prostorovou akustikou a s tím úzce spojenou problematikou doby dozvuku. Součástí práce je zpracování návrhu akustických úprav kostela na základě ručního výpočtu, který byl dále upravován ve specializovaném softwaru Odeon Room Acoustics Program. Pro okolní zástavbu kostela byla vytvořena hluková studie v programu Hluk+, aby bylo posouzeno, jaký bude mít tato novostavba hlukový dopad z kostelních zvonů dopad na své okolí. Na základě specializace, bylo v...

  3. gigapanorama of NA 62 cavern

    CERN Multimedia

    Brice, Maximilien

    2015-01-01

    The image shows the new rare Kaon decay experiment at CERN, called NA62. The NA62 experiment is 270 metres long and includes a 120-metre-long vacuum tank, shown here, housing several of the particle detectors. (Note: the experiment axis is a straight line, the curving of the tank is an optical effect of the photo.) Kaons are particles that decay into lighter elementary particles. The kaon decay processes are mostly well known, except for some very rare decay modes. For example, NA62 is investigating a rare decay predicted by the Standard Model in which a kaon decays into one pion and two neutrinos. This process occurs only once every 10 billion decays. The understanding of such ultra-rare decays are of great importance because they test the Standard Model in energy ranges not accessible by direct measurements. They are therefore complementary to the measurements at the LHC. ultra high definition on demand (photolab@cern.ch).

  4. OGLAŠEVANJE NA FACEBOOKU

    OpenAIRE

    Renko, Katica

    2013-01-01

    V magistrskem delu smo se seznanili z oglaševanjem na Facebooku. S pregledom gradiva, ki nam je ponujeno, smo preverili pogoje, načine, oblike … oglaševanja, ki pa smo jih s pregledom situacije v praksi preverili in dopolnili. Ob zaključku dela lahko rečemo, da je oglaševanje preko FB enostavnejše, cenejše, dostopnejše, omogoča nam ažurnost in samo komunikacijo z naslovniki, ki so potencialni kupci naših ponudb. Množični mediji nam omogočajo mnogotero obliko oglaševanja. Izbrana oblika ponuja...

  5. NA60 frees the quarks

    CERN Multimedia

    2003-01-01

    Fitted with new state-of-the-art silicon detectors, NA60 is prepared to study the phase transition from confined hadronic matter to a deconfined (free) quark-gluon plasma, a state of matter which probably existed an instant after the Big Bang.

  6. Hodler et Iéna

    OpenAIRE

    2017-01-01

    Suites de la protestation contre le bombardement de la cathédrale de Reims. Le recteur de l'Université de Jena propose d'enlever le tableau monumental de Hodler "Départ des étudiants d'Iéna pour la guerre de libération contre Napoléon en 1813".

  7. NA62: Hidden Sector Physics

    CERN Document Server

    Cesarotti, Carissa Joyce

    2016-01-01

    Modern experimental physics is often probing for new physics by either finding deviations from predictions on extremely precise measurements, or by looking for a new signal that cannot be explained with existing models. The NA62 experiment at CERN does the former by measuring the ultra-rare decay $K^+ \\rightarrow \\pi^+ \

  8. The system NaVO3-Na2WO4-Na2W2O7

    International Nuclear Information System (INIS)

    Kazanbekov, V.R.; Gasanaliev, A.M.; Kazanbekov, R.G.

    1994-01-01

    Phase diagrams of sodium metavanadate-sodium ditungstate, sodium metavanadate-sodium tungstate systems and surface of primary crystallization of sodium metavabadate-sodium tungstate-sodium ditungstate system were studied. The system sodium metavanadate-sodium ditungstate is eutectic one. Compound NaVO 3 x2Na 2 WO 4 is formed in solid state in sodium metavanadate-sodium tungstate system. Liquidus surface of sodium metavanadate-sodium tungstate-sodium ditungstate is presented by three crystallization fields of initial components. Composition and melting point of ternary eutectics are determined

  9. Europlanet NA2 Science Networking

    Science.gov (United States)

    Harri, Ari-Matti; Szego, Karoly; Genzer, Maria; Schmidt, Walter; Krupp, Norbert; Lammer, Helmut; Kallio, Esa; Haukka, Harri

    2013-04-01

    Europlanet RI / NA2 Science Networking [1] focused on determining the major goals of current and future European planetary science, relating them to the Research Infrastructure that the Europlanet RI project [2] developed, and placing them in a more global context. NA2 also enhanced the ability of European planetary scientists to participate on the global scene with their own agenda-setting projects and ideas. The Networking Activity NA2 included five working groups, aimed at identifying key science issues and producing reference books on major science themes that will bridge the gap between the results of present and past missions and the scientific preparation of the future ones. Within the Europlanet RI project (2009-2012) the NA2 and NA2-WGs organized thematic workshops, an expert exchange program and training groups to improve the scientific impact of this Infrastructure. The principal tasks addressed by NA2 were: • Science activities in support to the optimal use of data from past and present space missions, involving the broad planetary science community beyond the "space club" • Science activities in support to the preparation of future planetary missions: Earth-based preparatory observations, laboratory studies, R&D on advanced instrumentation and exploration technologies for the future, theory and modeling etc. • Develop scientific activities, joint publications, dedicated meetings, tools and services, education activities, engaging the public and industries • Update science themes and addressing the two main scientific objectives • Prepare and support workshops of the International Space Science Institute (ISSI) in Bern and • Support Trans National Activities (TNAs), Joined Research Activities (JRAs) and the Integrated and Distributed Information Service (IDIS) of the Europlanet project These tasks were achieved by WG workshops organized by the NA2 working groups, by ISSI workshops and by an Expert Exchange Program. There were 17 official WG

  10. Na+-stimulated ATPase of alkaliphilic halotolerant cyanobacterium Aphanothece halophytica translocates Na+ into proteoliposomes via Na+ uniport mechanism

    Directory of Open Access Journals (Sweden)

    Soontharapirakkul Kanteera

    2010-08-01

    Full Text Available Abstract Background When cells are exposed to high salinity conditions, they develop a mechanism to extrude excess Na+ from cells to maintain the cytoplasmic Na+ concentration. Until now, the ATPase involved in Na+ transport in cyanobacteria has not been characterized. Here, the characterization of ATPase and its role in Na+ transport of alkaliphilic halotolerant Aphanothece halophytica were investigated to understand the survival mechanism of A. halophytica under high salinity conditions. Results The purified enzyme catalyzed the hydrolysis of ATP in the presence of Na+ but not K+, Li+ and Ca2+. The apparent Km values for Na+ and ATP were 2.0 and 1.2 mM, respectively. The enzyme is likely the F1F0-ATPase based on the usual subunit pattern and the protection against N,N'-dicyclohexylcarbodiimide inhibition of ATPase activity by Na+ in a pH-dependent manner. Proteoliposomes reconstituted with the purified enzyme could take up Na+ upon the addition of ATP. The apparent Km values for this uptake were 3.3 and 0.5 mM for Na+ and ATP, respectively. The mechanism of Na+ transport mediated by Na+-stimulated ATPase in A. halophytica was revealed. Using acridine orange as a probe, alkalization of the lumen of proteoliposomes reconstituted with Na+-stimulated ATPase was observed upon the addition of ATP with Na+ but not with K+, Li+ and Ca2+. The Na+- and ATP-dependent alkalization of the proteoliposome lumen was stimulated by carbonyl cyanide m - chlorophenylhydrazone (CCCP but was inhibited by a permeant anion nitrate. The proteoliposomes showed both ATPase activity and ATP-dependent Na+ uptake activity. The uptake of Na+ was enhanced by CCCP and nitrate. On the other hand, both CCCP and nitrate were shown to dissipate the preformed electric potential generated by Na+-stimulated ATPase of the proteoliposomes. Conclusion The data demonstrate that Na+-stimulated ATPase from A. halophytica, a likely member of F-type ATPase, functions as an electrogenic Na

  11. Photodesorption of Na atoms from rough Na surfaces

    DEFF Research Database (Denmark)

    Balzer, Frank; Gerlach, R.; Manson, J.R.

    1997-01-01

    We investigate the desorption of Na atoms from large Na clusters deposited on dielectric surfaces. High-resolution translational energy distributions of the desorbing atoms are determined by three independent methods, two-photon laser-induced fluorescence, as well as single-photon and resonance......-enhanced two-photon ionization techniques. Upon variation of surface temperature and for different substrates (mica vs lithium fluoride) clear non-Maxwellian time-of-flight distributions are observed with a cos θ angular dependence and most probable kinetic energies below that expected of atoms desorbing from...... atoms are scattered by surface vibrations. Recent experiments providing time constants for the decay of the optical excitations in the clusters support this model. The excellent agreement between experiment and theory indicates the importance of both absorption of the laser photons via direct excitation...

  12. Photodesorption of Na atoms from rough Na surfaces

    DEFF Research Database (Denmark)

    Balzer, Frank; Gerlach, R.; Manson, J.R.

    1997-01-01

    atoms are scattered by surface vibrations. Recent experiments providing time constants for the decay of the optical excitations in the clusters support this model. The excellent agreement between experiment and theory indicates the importance of both absorption of the laser photons via direct excitation......We investigate the desorption of Na atoms from large Na clusters deposited on dielectric surfaces. High-resolution translational energy distributions of the desorbing atoms are determined by three independent methods, two-photon laser-induced fluorescence, as well as single-photon and resonance......-enhanced two-photon ionization techniques. Upon variation of surface temperature and for different substrates (mica vs lithium fluoride) clear non-Maxwellian time-of-flight distributions are observed with a cos θ angular dependence and most probable kinetic energies below that expected of atoms desorbing from...

  13. Obiteljska i bračna psihoterapija

    OpenAIRE

    Štalekar, Vlasta

    2010-01-01

    U radu je ukratko prikazana povijest obiteljske terapije na temelju koje se prati razvoj novih koncepata i terapijskih modela. Prikazana je podjela obiteljskih i bračnih terapija na brojne pravce, a navedene u ovom radu su sistemska, dinamska, strukturalna, strateška, transgeneracijska, iskustvena (prvenstveno je didaktičkog karaktera jer se u praksi ovi modeli uvelike preklapaju i nadopunjuju). Svaki terapijski model na jedinstven način tumači disfunkcije obiteljskog sustava t...

  14. Novel aspects of Na+,K+-ATPase

    OpenAIRE

    Aizman, Oleg

    2002-01-01

    Na,K-ATPase, an integral membrane protein expressed in each eukaryotic cell, serves as the major determinant of intracellular ion composition. In the current study we investigated novel aspects of Na,K-ATPase function and regulation. It is well established that Na,K-ATPase activity is regulated by reversible phosphorylation. New findings in this study are: 1) the level of intracellular Ca 2. concentration determines the functional effects of PKA and PKC-mediated Na,K-ATP...

  15. Carne suína

    OpenAIRE

    Ortigara, Claudino

    2000-01-01

    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. A carne suína é a fonte de proteína animal mais consumida no mundo. No entanto, em muitos países e em especial no Brasil o consumo per capita é muito baixo. Como conseqüência disso, limita-se o crescimento do segmento produtivo e uma série de benefícios socioeconômicos que são gerados pela atividade suinocultura.Com esse trabalho, buscamos uma explicação para entender a resistência da população ao consum...

  16. Economia na consulta de Endodontia

    OpenAIRE

    Pinto, Diogo Filipe Cardoso

    2016-01-01

    Introdução: Em Portugal a realidade actual, clínica e financeira do exercício da Medicina Dentária é bem distinta da do final do séc. XX devido à pletora de Médicos Dentistas e à baixa de honorários por acto Médico registada nos últimos anos. Objectivos: Este trabalho teve como objectivo perceber um pouco sobre os detalhes a ter em consideração aquando da abertura de uma clínica centrada na realização de tratamentos na área da Endodontia, e como publicitá-la de forma legal e apelativa. Pre...

  17. A Umbanda Portuguesa na Internet

    Directory of Open Access Journals (Sweden)

    Ismael Pordeus Júnior

    2004-01-01

    Full Text Available A partir de considerações sobre o processo de transculturação da Umbanda de Omolocô vou a propósito do grupo religioso do Terreiro de Umbanda Ogum Megê em Lisboa - Portugal discutir a textualização da memória. Como outras religiões que visam hoje o universal a Umbanda utiliza novas tecnologias disponíveis na Internet. Esse novo meio de comunicação favorece o processo de transculturação religiosa. Utilizando uma abordagem antropológica procuro realizar um estudo dos sites da Umbanda portuguesa na Internet, propondo uma visão ampla da utilização de novas tecnologias utilizadas para difusão da religião. Opto pelo estudo de caso, pois penso que permite uma melhor abordagem desse campo tecnológico.

  18. Otto Richard Gottlieb na UFRRJ

    OpenAIRE

    Raimundo Braz Filho; Universidade Estadual do Norte Fluminense Darcy Ribeiro; Mário Geraldo de Carvalho; Universidade Federal Rural do Rio de Janeiro

    2011-01-01

    Informações importantes da trajetória científica e produtiva do Prof. Otto Richard Gottlieb e sobre seu legado são revelados por dois de seus ex-alunos. Revelam sua perseverança na criação de grupos comprometidos com pesquisas em produtos naturais no Brasil. Inicialmente na Universidade de Brasília (UnB) e, em consequência de pressões políticas da década de sessenta, seu grupo deslocou-se para outras instituições recebendo apoio da Universidade Federal de Minas Gerais (UFMG), do Centro de Pes...

  19. Makosa Yanayofanywa na Wanafunzi Wanaojifunza Kiswahili kama ...

    African Journals Online (AJOL)

    Makala haya, yanashughulika na makosa ambayo hufanywa na wanafunzi wanaojifunza Kiswahili kama lugha ya pili katika shule za sekondari nchini Uganda. Mtafiti ameyaainisha makosa mbalimbali na kuyaeleza kiusahihi. Makala yanaeleza namna ambavyo makosa hayo hutokea. Yaani, kama ni makosa ...

  20. NA50 quark-gluon plasma experiment

    CERN Multimedia

    1997-01-01

    View of the NA50 detector, which studies quark-gluon plasma. The picture shows one of the six hodoscopes, made of 48 scintillator counters, used in the muon trigger of the NA50 spectrometer. The picture shows one of the six hodoscopes, made of 48 scintillator counters, used in the muon trigger of the NA50 spectrometer

  1. Pseudo-ternary phase diagram in the Na2O-Na2O2-NaOH system

    International Nuclear Information System (INIS)

    Saito, Jun-ichi; Tendo, Masayuki; Aoto, Kazumi

    1997-10-01

    Generally, the phase diagrams are always used to understand the present state of compounds at certain temperature. In order to understand the corrosion behavior of structural material for FBR by main sodium compounds (Na 2 O, Na 2 O 2 and NaOH), it is very important to comprehend the phase diagrams of their compounds. However, only Na 2 O-NaOH pseudo-binary phase diagram had been investigated previously in this system. There is no study of other pseudo-binary or ternary phase diagrams in the Na 2 O-Na 2 O 2 -NaOH system. In this study, in order to clarify the present states of their compounds at certain temperatures, the pseudo-binary and ternary phase diagrams in the Na 2 O-Na 2 O 2 -NaOH system were prepared. A series of thermal analyses with binary and ternary component system has been carried out using the differential scanning calorimetry (DSC). The liquidus temperature and ternary eutectic temperatures were confirmed by these measurements. The beneficial indications for constructing phase diagrams were obtained from these experiments. On the basis of these results, the interaction parameters between compounds which were utilized for the Thermo-Calc calculation were optimized. Thermo-Calc is one of thermodynamic calculation software. Consequently the accurate pseudo-binary and ternary phase diagrams were indicated using the optimized parameters. (author)

  2. Homocisteína Homocysteine

    Directory of Open Access Journals (Sweden)

    Lindalva Batista Neves

    2004-10-01

    Full Text Available A homocisteína, formada a partir da metionina hepática, é metabolizada nas vias de desmetilação e de transulfuração, sendo que seus valores plasmáticos e urinários refletem a síntese celular. Sua determinação, realizada em jejum e após sobrecarga de metionina, caracteriza as diferenças dessas vias metabólicas, principalmente quando de natureza genética. A hiper-homocisteinemia tem sido associada a maior risco de eventos aterotrombóticos, e a literatura sugere associação causal, independente de outros fatores de risco para doença arterial. Diminuição da homocisteína plasmática para valores normais é seguida de redução significante na incidência de doença aterotrombótica. A relação entre homocisteína e o fígado vem adquirindo importância nos dias atuais, uma vez que alterações das lipoproteínas e da depuração de metionina são comuns em pacientes com doença hepática crônica (hepatocelular e canalicular. O tratamento da hiper-homocisteinemia fundamenta-se na suplementação alimentar e medicamentosa de ácido fólico e vitaminas B6 e B12.Homocysteine, formed from hepatic methionine, is metabolized through the pathways of demethylation and transsulfuration. Its plasmatic and urinary values reflect the cell synthesis. Its determination after fasting and increased infusion of methionine shows the differences of these two metabolic pathways, mainly when it is related to genetic diseases. Hyperhomocysteinemia has been associated with a higher risk of vascular thrombotic events. Several authors suggest a causal relationship between these events independently of other risk factors for vascular diseases. Decrease in plasmatic homocysteine to normal levels is followed by a significant reduction on the incidence of vascular thrombotic events. The correlation between the liver and homocysteine is becoming more important because of the recent findings that alterations of lipoproteins and methionine clearance are

  3. Myocardial Na,K-ATPase: Clinical aspects

    OpenAIRE

    Kjeldsen, Keld

    2003-01-01

    The specific binding of digitalis glycosides to Na,K-ATPase is used as a tool for Na,K-ATPase quantification with high accuracy and precision. In myocardial biopsies from patients with heart failure, total Na,K-ATPase concentration is decreased by around 40%; a correlation exists between a decrease in heart function and a decrease in Na,K-ATPase concentration. During digitalization, around 30% of remaining pumps are occupied by digoxin. Myocardial Na,K-ATPase is also influenced by other drugs...

  4. Istraživanje uticaja nekih parametara na osetljivost eksplozivnih materija na toplotni impuls

    OpenAIRE

    Jeremić Radun

    2002-01-01

    Ispitivana je osetljivost nekoliko vrsta eksplozivnih materija na toplotni impuls merenjem vremena zadrške u zavisnosti od temperature. Na osnovu eksperimentalnih rezultata određene su vrednosti energije aktivacije i predeksponencijalni faktori u jednačini Semjonova. Istraživan je i uticaj mase ispitivanog uzorka, granulacije i veličine kristala eksploziva na osetljivost na toplotni impuls. Pokazano je da ovi parametri imaju značajan uticaj na osetljivost eksplozivnih materija, pa je neophodn...

  5. Silicene for Na-ion battery applications

    KAUST Repository

    Zhu, Jiajie

    2016-08-19

    Na-ion batteries are promising candidates to replace Li-ion batteries in large scale applications because of the advantages in natural abundance and cost of Na. Silicene has potential as the anode in Li-ion batteries but so far has not received attention with respect to Na-ion batteries. In this context, freestanding silicene, a graphene-silicene-graphene heterostructure, and a graphene-silicene superlattice are investigated for possible application in Na-ion batteries, using first-principles calculations. The calculated Na capacities of 954mAh/g for freestanding silicene and 730mAh/g for the graphenesilicene superlattice (10% biaxial tensile strain) are highly competitive and potentials of >0.3 V against the Na/Na potential exceed the corresponding value of graphite. In addition, the diffusion barriers are predicted to be <0.3 eV.

  6. Hali ya taaluma ya ukalimani Tanzania: jana, leo na kesho ...

    African Journals Online (AJOL)

    Umuhimu wa ukalimani katika mawasiliano umeongezeka kutokana na utandawazi. Utandawazi umerahisisha kukutanika na kuwasiliana kwa watu wazungumzao lugha tofauti kupitia wakalimani. Kutokana na ongezeko hilo la umuhimu wa ukalimani, kumekuwa na jitihada mbalimbali katika nchi mbalimbali kuhakikisha ...

  7. Docência na universidade: professores inovadores na USP

    Directory of Open Access Journals (Sweden)

    Chamlian Helena Coharik

    2003-01-01

    Full Text Available O artigo trata de pesquisa realizada com um grupo de professores inovadores da Universidade de São Paulo tendo como objetivo procurar subsídios para a formação do professor universitário. Esses docentes foram entrevistados, solicitando que detalhassem melhor suas experiências inovadoras; explicassem as razões pelas quais haviam introduzido modificações em sua forma de trabalho; explicitassem as relações entre sua atividade de docência e de pesquisa, expressassem o papel que atribuíam ao ensino na universidade, bem como a forma pela qual sua trajetória acadêmica havia se cumprido até então. A diversidade de experiências relatadas e, ao mesmo tempo, a convergência de visões a respeito de suas funções de ensino e de pesquisa na universidade permitem-nos afirmar que, mais do que uma formação pedagógica específica, a sensibilização para as dificuldades do ensino e a valorização institucional dessa atividade consistiriam em grande avanço para a formação do professor.

  8. Na alvorada de um sport

    OpenAIRE

    Sartori, Carina

    2013-01-01

    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas, Programa de Pós-graduação em História, Florianópolis, 2013 Em Florianópolis, a primeira Sociedade de Regatas organizada, meados do século XIX, contaria com a participação dos Coronéis da Marinha e da Escola de Menores e Marinheiros da Canhoneira. Na virada do século, a fundação do Clube 29 de Abril permitiria que as atividades relacionadas ao Remo fossem oferecidas a todos que se associ...

  9. A Umbanda Portuguesa na Internet

    OpenAIRE

    Ismael Pordeus Júnior

    2004-01-01

    A partir de considerações sobre o processo de transculturação da Umbanda de Omolocô vou a propósito do grupo religioso do Terreiro de Umbanda Ogum Megê em Lisboa - Portugal discutir a textualização da memória. Como outras religiões que visam hoje o universal a Umbanda utiliza novas tecnologias disponíveis na Internet. Esse novo meio de comunicação favorece o processo de transculturação religiosa. Utilizando uma abordagem antropológica procuro realizar um estudo dos sites da Umbanda portuguesa...

  10. Relationship between intracellular Na+ concentration and reduced Na+ affinity in Na+,K+-ATPase mutants causing neurological disease

    DEFF Research Database (Denmark)

    Toustrup-Jensen, Mads Schak; Einholm, Anja P.; Schack, Vivien

    2014-01-01

    The neurological disorders familial hemiplegic migraine type 2 (FHM2), alternating hemiplegia of childhood (AHC), and rapid-onset dystonia parkinsonism (RDP) are caused by mutations of Na+,K+-ATPase α2- and α3-isoforms, expressed in glial and neuronal cells, respectively. Although these disorders......, addressing the question to what extent they cause a change of the intracellular Na+ and K+ concentrations ([Na+]i and [K+]i) in COS cells. C-terminal extension mutants generally showed dramatically reduced Na+ affinity without disturbance of K+ binding, as did other RDP mutants. No phosphorylation from ATP...... was observed for the +28 mutation of α2, despite a high expression level. A significant rise of [Na+]i and reduction of [K+]i was detected in cells expressing mutants with reduced Na+ affinity, and did not require a concomitant reduction of the maximal catalytic turnover rate or expression level. Moreover, two...

  11. O ATLETISMO NA PERSPECTIVA EDUCACIONAL

    Directory of Open Access Journals (Sweden)

    Leandro Araujo de Sousa

    2017-06-01

    Full Text Available A educação física escolar deve proporcionar experiências aos alunos para o seu desenvolvimento integral. As aulas muitas vezes são reduzidas ao ensino de esportes tradicionais, o que limita o repertório de movimentos dos alunos. Dessa forma o presente estudo de revisão objetiva problematizar o atletismo no ambiente escolar e propor possibilidades pedagógicas para seu ensino. Nesta pesquisa propomos tratar o ensino do atletismo na escola, caracterizando-o pelo seu repertório de movimentos que são naturais ao ser humano, como correr, saltar e lançar, o que possibilita maior praticidade em sua aplicação pedagógica, porém essas possibilidades não são consideradas no ambiente educacional. Diante dos dados encontrados, sugerimos que esse esporte seja abordado de forma multidimensional no ambiente escolar contextualizando-o à visão de algumas correntes teóricas. Nessa perspectiva do esporte educacional, o atletismo pode, assim como deve ser trabalhado nas aulas de educação física como instrumento pedagógico de ensino e auxiliar na formação do aluno de forma global.

  12. Identidades Homossexuais na Territorialidade Tradicionalista

    Directory of Open Access Journals (Sweden)

    Edipo Djavan dos Reis Göergen

    2015-12-01

    Full Text Available Este artigo apresenta o debate teórico que sustenta a pesquisa de mestrado desenvolvida pelo autor. Tendo por base suas vivências em contextos de tradicionalismo gaúcho, o autor deste trabalho tem percebido a grande quantidade de homossexuais, ou indivíduos que se auto-denominam não-heterossexuais, integrando as atividades artísticas do Movimento Tradicionalista Gaúcho, ou a territorialidade tradicionalista. Interessado em investigar tal fenômeno, o autor tem desenvolvido o projeto de pesquisa “Os Espaços Paradoxais de Relações Homoeróticas na Territorialidade Tradicionalista”, sob orientação do prof. Dr. Benhur Pinós da Costa, no Programa de Pós-Graduação em Geografia (UFSM. Para que essa pesquisa seja realizada, levam-se em conta as relações de gênero e de sexualidade que estão envolvidas no tema. Dessa forma, por ainda se tratarem de temáticas tidas como insignificantes na sociedade em geral e marginalizadas no campo científico, para que o presente trabalho fosse empreendido, buscou-se amparo teórico nas geografias feministas e queer, segmentos contemporâneos da ciência geográfica.

  13. Micotoxinas e Micotoxicoses na Avicultura

    Directory of Open Access Journals (Sweden)

    Santurio JM

    2000-01-01

    Full Text Available Esta revisão tem como objetivo principal mostrar, baseado em dezenas de pesquisas realizadas, os efeitos tóxicos das micotoxinas aflatoxinas, tricotecenos, zealenona e fumonisinas sobre o desempenho das aves. O descobrimento das propriedades hepatotóxicas e hepatocarcinogênicas de algumas linhagens de Aspergillus flavus e A. parasiticus em perus, na Inglaterra, no início da década de 1960, seguida pela elucidação da estrutura de seus metabólitos tóxicos, as aflatoxinas, deu novo enfoque e prioridade para a pesquisa sobre micotoxinas. Análises de aflatoxinas realizadas no Laboratório de Análises Micotoxicológicas (LAMIC da Universidade Fedaral de Santa Maria, entre os anos de 1986 e janeiro de 2000, em 15.600 amostras de alimentos destinados principalmente ao consumo animal, demonstram que no milho analisado, 41,9% das amostras estavam contaminadas por aflatoxinas. Em surtos de aflatoxicose no campo, uma das características mais marcantes é a má absorção que se manifesta como partículas de ração mal digeridas na excreta das aves. Também observa-se, em frangos e poedeiras que recebem AFL, extrema palidez das mucosas e pernas. Dietas deficientes em riboflavina ou colecalciferol (vit. D tornaram frangos sensíveis, nos índices de desenvolvimento corporal, a concentrações muito baixas de AFL. O efeito aflatoxina nos frangos é maior na fase inicial de crescimento, ou seja, quando as aves ingeriram aflatoxina nos primeiros 21 dias de vida, e quanto maior o nível de stress do lote, menor a quantidade de AFL para afetar negativamente seu desempenho, seja na produção de carne ou de ovos. As principais micotoxinas do grupo dos tricotecenos são: toxina T-2; deoxynivalenol (DON; diacetoxyscirpenol (DAS, todas produzidas através de diversas espécies de fungos do gênero Fusarium. Além dos tricotecenos, o fusarium também pode produzir zearalenona e fumonisinas. Dessas fusarium-toxinas, somente toxina T-2 gera patologias s

  14. Fotografia na Imprensa: conflitos na câmara escura

    Directory of Open Access Journals (Sweden)

    José Lúcio da Silva Menezes

    2014-07-01

    Full Text Available Este artigo recupera o teor ideológico do discurso que a Revista Veja elaborou sobre a classe trabalhadora que emergiu no cenário brasileiro, no final da década de 1970. O destaque dado aos trabalhadores como temática central resgatada, deve-se aos movimentos grevistas por eles encetados, após anos de ocultamento de sua resistência sob a repressão da ditadura civil-militar (1964-1985. Com a rebeldia operária, as matérias a respeito deste grupo, na Revista,foram se tornando mais constantes e visíveis, pois já não era mais possível, para a Revista Veja, ignorar a existência da classe operária que, com a força insurgente das greves, ocupava as ruas do Brasil.

  15. Vpliv toplotnih mostov na porabo energije za ogrevanje na primeru osnovne šole

    OpenAIRE

    Megušar, Primož

    2015-01-01

    Na primeru Osnovne šole Dobrova sem preveril, kakšen vpliv imajo dejanski toplotni mostovi na porabo energije za ogrevanje. Iz načrtov stavbe sem evidentiral vse toplotne mostove, kateri vplivajo na porabo energije. Tem toplotnim mostovom sem nato v standardu SIST EN ISO 14683 poiskal ustrezne približke. Nato sem s programom TOST izvedel tri simulacije. V prvem primeru toplotnih mostov nisem upošteval. V drugem primeru sem toplotne mostove upošteval na poenostavljen način, v zadnjem primeru p...

  16. Na and K dependence of the Na/K pump in cystic fibrosis fibroblasts.

    OpenAIRE

    Reznik, V M; Schneider, J A; Mendoza, S A

    1981-01-01

    The Na and K dependence of the Na/K pump was measured in skin fibroblasts from patients with cystic fibrosis and age/sex-matched controls. Under basal conditions, there was no difference between control and cystic fibrosis cells in protein per cell, intracellular Na and K content, or Na/K pump activity (measured as ouabain-sensitive 86Rb uptake). There was no difference in the Na dependence of the Na/K pump between cystic fibrosis cells and control cells. In cells from patients with cystic fi...

  17. Modification of single Na+ channels by batrachotoxin.

    Science.gov (United States)

    Quandt, F N; Narahashi, T

    1982-11-01

    The modifications in the properties of voltage-gated Na+ channels caused by batrachotoxin were studied by using the patch clamp method for measuring single channel currents from excised membranes of N1E-115 neuroblastoma cells. The toxin-modified open state of the Na+ channel has a decreased conductance in comparison to that of normal Na+ channels. The lifetime of the modified open state is drastically prolonged, and channels now continue to open during a maintained depolarization so that the probability of a channel being open becomes constant. Modified and normal open states of Na+ channels coexist in batrachotoxin-exposed membrane patches. Unlike the normal condition, Na+ channels exposed to batrachotoxin open spontaneously at large negative potentials. These spontaneous openings apparently cause the toxin-induced increase in Na+ permeability which, in turn, causes membrane depolarization.

  18. Low-spin states of 23Na

    International Nuclear Information System (INIS)

    Bakkum, E.L.

    1987-01-01

    A study of 23 Na via the 22 Ne(p,γ) 23 Na and 23 Na(γ,γ) 23 Na reactions is presented. Only a limited number of resonances has been studied, selected on the basis of strong excitation of the lowest levels of which the spin was unknown. As a result the spins are now known of all levels of 23 Na with excitation energies up to 7 MeV, except for a few high-spin states which are too weakly excited in the decay of the known 22 Ne(p,γ) resonances. The mean lifetimes of the 23 Na levels at 4.43 and 7.89 MeV were found to be 350±70 and 220±17 attoseconds (1 attosecond = 10 -18 seconds) respectively. 97 refs.; 22 figs.; 12 tabs

  19. Modification of single Na+ channels by batrachotoxin.

    OpenAIRE

    Quandt, F N; Narahashi, T

    1982-01-01

    The modifications in the properties of voltage-gated Na+ channels caused by batrachotoxin were studied by using the patch clamp method for measuring single channel currents from excised membranes of N1E-115 neuroblastoma cells. The toxin-modified open state of the Na+ channel has a decreased conductance in comparison to that of normal Na+ channels. The lifetime of the modified open state is drastically prolonged, and channels now continue to open during a maintained depolarization so that the...

  20. PRIMERJAVA GEODETSKIH METOD NA ZAHTEVNEM GRADBENEM OBJEKTU

    OpenAIRE

    Reberčnik, Matic

    2017-01-01

    V projektni nalogi smo v uvodnih poglavjih predstavili različne načine izvajanja geodetskih meritev, ki jih v gradbeništvu uporabljamo pri analizi pomikov in deformacij gradbenih konstrukcij ter terena, na katerem so le-te postavljene. V nadaljevanju opisujemo terestične in GNSS (globalni navigacijski satelitski sistem) metode, ki smo jih uporabljali pri izvajanju meritev na izbranem premostitvenem objektu avtocestnega odseka v Sloveniji (zaradi varovanja podatkov ga imenujemo Objekt 1). Pod...

  1. Ionic dependence of active Na-K transport: clamping of cellular Na+ with monensin

    International Nuclear Information System (INIS)

    Haber, R.S.; Pressley, T.A.; Loeb, J.N.; Ismail-Beigi, F.

    1987-01-01

    The Na + ionophore monensin was used to study the Na + - and K + -dependence of ouabain-inhibitable 86 Rb + uptake in ARL 15 cells, a rat liver cell line. Graded concentrations of monensin rapidly induced incremental elevations of cellular Na + that were stable for up to 2 h. In experiments in which cellular Na + was thus clamped at various levels, the activation curve for ouabain-inhibitable 86 Rb + uptake as a function of intracellular Na + was found to be steepest near basal Na + levels (Hill coefficient /congruent/ 2.4), indicating that these cells can respond to relatively large changes in passive Na + entry by increasing the rate of Na-K pump function with only minimal increases in cellular Na + . Exposure of cells to monensin also permitted examination of the extracellular-K + dependence of ouabain inhibitable 86 Rb + uptake in presence of saturating intracellular Na + and yielded a Hill coefficient of ∼ 1.5. The rate of ATP hydrolysis calculated from measurements of the maximal rate of ouabain-inhibitable 86 Rb + uptake in intact cells was similar to the enzymatic V/sub max/ of the Na + -K + -ATPase in cell lysates, suggesting that the Na + -K + -ATPase activity in these broken-cell preparations closely reflects the functional transport capacity of the Na-K pump

  2. Fabrication of implanted $^{22}$Na targets

    CERN Multimedia

    2002-01-01

    A knowledge of the $^{22}$Na(p,$\\gamma$)$^{23}$ Mg reaction rate is of significant astrophysical interest. In order to complete previous studies of this reaction, radioactive $^{22}$Na targets of high purity are required. We ask for support to fabricate these targets via the implantation technique at ISOLDE GPS (off—line mode) using $^{22}$Na nuclides in an Al matrix produced in Nov. 1990 at the PSI (Zürich). The $^{22}$Na nuclides are released and ionized in a surface ionisation source, mass-analyzed at ISOLDE GPS, and implanted in a Ni-Ta backing and a C—foil in a special implantation setup.

  3. OGLAŠEVANJE NA FACEBOOKU V SLOVENIJI

    OpenAIRE

    Dobnik, Monja

    2013-01-01

    Danes so zahvaljujoč napredni mobilni tehnologiji družbena omrežja z nami na vsakem koraku. Facebook (FB) se po priljubljenosti uvršča v sam vrh družbenih omrežij in glede na to, da ga uporablja že več kot milijarda zemljanov, ponuja tudi odlične trg za oglaševanje. To so ugotovili tudi slovenski podjetniki. V diplomski nalogi je predstavljeno, kako na FB oglašujejo nekatera slovenska podjetja, s pomočjo spletnega vprašalnika pa je ugotovljeno tudi, kaj o oglasih na FB menijo njegovi uporabni...

  4. Na+ Recirculation and Isosmotic Transport

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Møbjerg, N

    2006-01-01

    of the absorbate. Mathematical modeling reproducing bioelectric and hydrosmotic properties of small intestine and proximal tubule, respectively, predicts a significant range of observations such as isosmotic transport, hyposmotic transport, solvent drag, anomalous solvent drag, the residual hydraulic permeability...... external baths. Hyperosmolarity of lis is governed by the hydraulic permeability of the apical plasma membrane and tight junction with 6-7 mOsm in small intestine and transport demands a Na(+) recirculation of 50-70% in small intestine but might be barely...... measurable in proximal tubule. The model fails to reproduce a certain type of observations: The reduced volume absorption at transepithelial osmotic equilibrium in AQP1 knockout mice, and the stimulated water absorption by gallbladder in diluted external solutions. Thus, it indicates cellular regulation...

  5. O consumo na vida digital

    Directory of Open Access Journals (Sweden)

    Iuri Yudi Furukita Baptista

    2016-02-01

    Full Text Available O modelo de consumo não possui as mesmas características sempre: suas relações, motivações, formatos, espaços, interesses e atividades são construções sociais que se modificam atreladas ao cenário econômico, político e tecnológico. O presente trabalho repassa o surgimento da sociedade do consumidor para então conjecturar sobre as propriedades distintivas do consumo na vida digital. O que se defende ao final é que o consumidor já não se restringe ao papel de consumir.

  6. Na+/Ca2+ exchange and Na+/K+-ATPase in the heart

    Science.gov (United States)

    Shattock, Michael J; Ottolia, Michela; Bers, Donald M; Blaustein, Mordecai P; Boguslavskyi, Andrii; Bossuyt, Julie; Bridge, John H B; Chen-Izu, Ye; Clancy, Colleen E; Edwards, Andrew; Goldhaber, Joshua; Kaplan, Jack; Lingrel, Jerry B; Pavlovic, Davor; Philipson, Kenneth; Sipido, Karin R; Xie, Zi-Jian

    2015-01-01

    This paper is the third in a series of reviews published in this issue resulting from the University of California Davis Cardiovascular Symposium 2014: Systems approach to understanding cardiac excitation–contraction coupling and arrhythmias: Na+ channel and Na+ transport. The goal of the symposium was to bring together experts in the field to discuss points of consensus and controversy on the topic of sodium in the heart. The present review focuses on cardiac Na+/Ca2+ exchange (NCX) and Na+/K+-ATPase (NKA). While the relevance of Ca2+ homeostasis in cardiac function has been extensively investigated, the role of Na+ regulation in shaping heart function is often overlooked. Small changes in the cytoplasmic Na+ content have multiple effects on the heart by influencing intracellular Ca2+ and pH levels thereby modulating heart contractility. Therefore it is essential for heart cells to maintain Na+ homeostasis. Among the proteins that accomplish this task are the Na+/Ca2+ exchanger (NCX) and the Na+/K+ pump (NKA). By transporting three Na+ ions into the cytoplasm in exchange for one Ca2+ moved out, NCX is one of the main Na+ influx mechanisms in cardiomyocytes. Acting in the opposite direction, NKA moves Na+ ions from the cytoplasm to the extracellular space against their gradient by utilizing the energy released from ATP hydrolysis. A fine balance between these two processes controls the net amount of intracellular Na+ and aberrations in either of these two systems can have a large impact on cardiac contractility. Due to the relevant role of these two proteins in Na+ homeostasis, the emphasis of this review is on recent developments regarding the cardiac Na+/Ca2+ exchanger (NCX1) and Na+/K+ pump and the controversies that still persist in the field. PMID:25772291

  7. Analiza utjecaja stabilizatora na određivanje elemenata vanjske orijentacije kamere na bespilotnoj letjelici

    OpenAIRE

    Gašparović, Mateo; Gajski, Dubravko

    2016-01-01

    U radu su prikazani i interpretirani rezultati analize utjecaja stabilizatora kamere na određivanje elemenata vanjske orijentacije na bespilotnim letjelicama. Riječ je o 3-osnom stabilizatoru baziranom na elektromotorima bez četkica. Prikazan je i objašnjen koncept rada stabilizatora kamera na bespilotnim letjelicama. Za potrebe rada stabilizator je unaprijeđen upotrebom drugog inercijalnog mjernog uređaja (IMU). Provedena su dva testiranja stabilizatora upotrebom jednog i dva inercijalna mje...

  8. Na+,K+-ATPase Na+ affinity in rat skeletal muscle fiber types

    DEFF Research Database (Denmark)

    Kristensen, Michael; Juel, Carsten

    2010-01-01

    Previous studies in expression systems have found different ion activation of the Na(+)/K(+)-ATPase isozymes, which suggest that different muscles have different ion affinities. The rate of ATP hydrolysis was used to quantify Na(+),K(+)-ATPase activity, and the Na(+) affinity of Na(+),K(+)-ATPase......Previous studies in expression systems have found different ion activation of the Na(+)/K(+)-ATPase isozymes, which suggest that different muscles have different ion affinities. The rate of ATP hydrolysis was used to quantify Na(+),K(+)-ATPase activity, and the Na(+) affinity of Na......(+),K(+)-ATPase was studied in total membranes from rat muscle and purified membranes from muscle with different fiber types. The Na(+) affinity was higher (K(m) lower) in oxidative muscle compared with glycolytic muscle and in purified membranes from oxidative muscle compared with glycolytic muscle. Na......(+),K(+)-ATPase isoform analysis implied that heterodimers containing the beta(1) isoform have a higher Na(+) affinity than heterodimers containing the beta(2) isoform. Immunoprecipitation experiments demonstrated that dimers with alpha(1) are responsible for approximately 36% of the total Na,K-ATPase activity. Selective...

  9. Exploration of NaVOPO4 as a cathode for a Na-ion battery.

    Science.gov (United States)

    Song, Jie; Xu, Maowen; Wang, Long; Goodenough, John B

    2013-06-11

    Monoclinic NaVOPO4 is explored as a cathode material for a sodium ion battery. It exhibits electrochemical activity operating at an average potential of 3.6 V (vs. Na(+)/Na) and delivers a reversible capacity of 90 mA h g(-1) at 1/15 C.

  10. Effects of CaO/P2O5 ratio on the structure and elastic properties of SiO2-CaO-Na2O-P2O5 bioglasses.

    Science.gov (United States)

    Lin, Chung-Cherng; Chen, Shih-Fan; Leung, Kak Si; Shen, Pouyan

    2012-02-01

    The evolution of elastic properties and structure upon the change of CaO/P(2)O(5) ratio in SiO(2)-CaO-Na(2)O-P(2)O(5) glasses (45S5-derived and 55S4-derived) at ambient conditions has been studied by using both Brillouin and Raman spectroscopy coupled with X-ray diffraction. Under the same SiO(2)/Na(2)O ratio, it is found that a decrease in CaO/P(2)O(5) molar ratio has caused a more-polymerized silicate network via a net consumption of Q(0), Q(1), and Q(2) species yet enriching in Q(3) and Q(4) species. Brillouin experiments revealed that all the bulk, shear and Young's moduli of the glasses studied increases with the increase of CaO/P(2)O(5) molar ratio. The unexpected variation trend in shear modulus can be correlated to the contribution from cohesion, the less-polymerized phosphate Q species, and density. Compared to the 45S5-derived, the more-polymerized 55S4-deived glass has a lower bulk but slightly higher shear modulus at the given CaO/P(2)O(5) ratio.

  11. Study of the Na-C-O and Na-H-O ternary systems in the sodium rich corner

    International Nuclear Information System (INIS)

    Maupre, J.-P.

    1978-02-01

    The purpose of this study is to provide a contribution to the understanding of the sodium - carbon - oxygen and sodium - hydrogen - oxygen ternary systems in the sodium rich corner. In order to do this the Na-NaH-Na 2 O-NaOH phase diagram was completed and the Na-Na 2 O-Na 2 CO 3 -C phase diagram was outlined. This work is made up of two parts. The first is devoted to a critical literature survey essential to establish correct phase diagrams. The second is an experimental study followed by a discussion collating our finding to the literary data. The basic experimental technique used is differential thermal analysis (DTA) but it has been completed by quenching, X-ray and chemical analysis methods. The proposed phase diagrams imply that Na-NaH-Na 2 O-NaOH and Na-Na 2 O-Na 2 CO 3 -C systems are reciprocal ternary systems. Temperatures of stable pairs reversal are respectively 410 and 690 0 C. The stable pairs are Na-NaOH and Na-Na 2 CO 3 at elevated temperature, Na 2 O-NaH and Na 2 O-C at low temperature [fr

  12. OGLAŠEVANJE NA DRUŽBENIH OMREŽJIH NA PRIMERU FACEBOOKA

    OpenAIRE

    Novak, Martina

    2012-01-01

    V diplomskem delu obravnavamo družbene medije kot novo priložnost za promocijo in oglaševanje podjetij. Spoznali smo družbena omrežja na splošno in nekaj teh, ki jih uporabljamo tudi v Sloveniji na kratko predstavili. Podrobneje smo se osredotočili na družbeno omrežje Facebook, predvsem na samo spletno stran, njen izgled in storitve, ki jih ponuja uporabnikom. V nalogi je podrobneje opisan Facebook kot orodje za uporabo oglaševanja. Spoznali smo brezplačne in plačljive načine promocije in ogl...

  13. Extracellular Na+ levels regulate formation and activity of the NaX/alpha1-Na+/K+-ATPase complex in neuronal cells.

    Directory of Open Access Journals (Sweden)

    Emmanuelle eBerret

    2014-12-01

    Full Text Available MnPO neurons play a critical role in hydromineral homeostasis regulation by acting as sensors of extracellular sodium concentration ([Na+]out. The mechanism underlying Na+-sensing involves Na+-flow through the NaX channel, directly regulated by the Na+/K+-ATPase α1-isoform which controls Na+-influx by modulating channel permeability. Together, these two partners form a complex involved in the regulation of intracellular sodium ([Na+]in. Here we aim to determine whether environmental changes in Na+ could actively modulate the NaX/Na+/K+-ATPase complex activity.We investigated the complex activity using patch-clamp recordings from rat MnPO neurons and Neuro2a cells. When the rats were fed with a high-salt-diet, or the [Na+] in the culture medium was increased, the activity of the complex was up-regulated. In contrast, drop in environmental [Na+] decreased the activity of the complex. Interestingly under hypernatremic condition, the colocalization rate and protein level of both partners were up-regulated. Under hyponatremic condition, only NaX protein expression was increased and the level of NaX/Na+/K+-ATPase remained unaltered. This unbalance between NaX and Na+/K+-ATPase pump proportion would induce a bigger portion of Na+/K+-ATPase-control-free NaX channel. Thus we suggest that hypernatremic environment increases NaX/Na+/K+-ATPase α1-isoform activity by increasing the number of both partners and their colocalization rate, whereas hyponatremic environment down-regulates complex activity via a decrease in the relative number of NaX channels controlled by the pump.

  14. K+ congeners that do not compromise Na+ activation of the Na+,K+-ATPase

    DEFF Research Database (Denmark)

    Mahmmoud, Yasser A; Kopec, Wojciech; Khandelia, Himanshu

    2015-01-01

    to no antagonism to cytoplasmic Na(+) activation. Na(+),K(+)-ATPase structures revealed a previously undescribed rotamer transition of the hydroxymethyl side chain of the absolutely conserved Thr(772) of the α-subunit. The side chain contributes its hydroxyl to Na(+) in site I in the E1 form and rotates......The Na(+),K(+)-ATPase is essential for ionic homeostasis in animal cells. The dephosphoenzyme contains Na(+) selective inward facing sites, whereas the phosphoenzyme contains K(+) selective outward facing sites. Under normal physiological conditions, K(+) inhibits cytoplasmic Na(+) activation...... to contribute its methyl group toward K(+) in the E2 form. Molecular dynamics simulations to the E1·AlF4 (-)·ADP·3Na(+) structure indicated that 1) bound organic cations differentially distorted the ion binding sites, 2) the hydroxymethyl of Thr(772) rotates to stabilize bound Form(+) through water molecules...

  15. Crystal structure of Na+, K(+)-ATPase in the Na(+)-bound state.

    Science.gov (United States)

    Nyblom, Maria; Poulsen, Hanne; Gourdon, Pontus; Reinhard, Linda; Andersson, Magnus; Lindahl, Erik; Fedosova, Natalya; Nissen, Poul

    2013-10-04

    The Na(+), K(+)-adenosine triphosphatase (ATPase) maintains the electrochemical gradients of Na(+) and K(+) across the plasma membrane--a prerequisite for electrical excitability and secondary transport. Hitherto, structural information has been limited to K(+)-bound or ouabain-blocked forms. We present the crystal structure of a Na(+)-bound Na(+), K(+)-ATPase as determined at 4.3 Å resolution. Compared with the K(+)-bound form, large conformational changes are observed in the α subunit whereas the β and γ subunit structures are maintained. The locations of the three Na(+) sites are indicated with the unique site III at the recently suggested IIIb, as further supported by electrophysiological studies on leak currents. Extracellular release of the third Na(+) from IIIb through IIIa, followed by exchange of Na(+) for K(+) at sites I and II, is suggested.

  16. LEITURA E LEITURA NA UNIVERSIDADE

    Directory of Open Access Journals (Sweden)

    Profª Drª Márcia A. G. Molina

    2015-12-01

    Full Text Available O texto apresenta uma discussão acerca da leitura, traçando, primeiramente, um percurso histórico dessa questão, iniciando-se no XIX aqui no Brasil.. Na sequência, aponta-se para a importância daquele que trabalha com a leitura ter paixão por ela, para que possa formar sujeitos também apaixonados pelo ato de ler. Continua mostrando os tipos de leitura, de acordo com FREIRE (1989, KOCK e ELIAS (2006 e apontando as atuais orientações para os procedimentos de leitura de um texto, baseados em KLEIMAN (2002. Conclui-se que, para formar o bom leitor, entendido como aquele que lê o não-dito e caminha para além da paráfrase reprodutiva, deve-se: ter paixão pela leitura, orientar os estudantes para essa prática, estabelecendo-se objetivos de leitura e reconhecer as estratégias que compreendem essa atividade.

  17. Necessidades da vida na morte

    Directory of Open Access Journals (Sweden)

    Denise Stefanoni Combinato

    2017-04-01

    Full Text Available Em função do envelhecimento populacional e aumento de doenças crônicas não transmissíveis, a Estratégia Saúde da Família (ESF tem se deparado com as necessidades das pessoas em processo de morte. A partir da análise do trabalho de profissionais da saúde que cuidaram de pessoas em processo de morte, o objetivo deste artigo é discutir as necessidades de saúde nesse processo, a fim de subsidiar o trabalho com essa população, especialmente na Atenção Primária à Saúde. Participaram da entrevista, após serem selecionados por dois questionários, onze profissionais (enfermeiros e médicos da ESF de Campinas/SP. A análise de dados foi pautada no referencial teórico-metodológico da Psicologia histórico-cultural. Como resultado, tem-se que as necessidades dos pacientes e familiares não são restritas ao momento de vida (proximidade da morte, mas referem-se, também, às condições de vulnerabilidade social.

  18. Terapia de linguagem na afasia

    Directory of Open Access Journals (Sweden)

    Mauro Spinelli

    1977-12-01

    Full Text Available A terapia da linguagem na afasia foi estudada em 15 pacientes, 8 do sexo masculino e 7 do sexo feminino; a idade variou de menos de 10 anos a mais de 50 anos; em 11 casos a afasia era sequela de acidente vascular cerebral e, em 4, de traumatismo crânio-encefálico. Quanto ao tipo de afasia, 5 pacientes apresentavam déficits predominantemente de expressão e 10 apresentavam déficits receptivos e expressivos em graus equiparáveis. Em 6 casos a terapia foi iniciada dentro dos 3 primeiros meses de instalação do quadro; nos restantes foi iniciada mais tardiamente. Dos 15 pacientes, 11 apresentaram evolução satisfatória, a qual não depndeu do grau de afasia, do tipo de afasia, da idade do paciente, do tipo de patologia e do intervalo entre a instalação do quadro afásico e o início da terapia. A terapia da linguagem no paciente afásico é efetiva, o prognóstico não pode ser feito a priori. Somente a evolução do caso com sua retestagem criteriosa poderá dar dados realmente úteis para se falar em evolução.

  19. Liquido cefalorraquiano na cisticercose encefalica

    Directory of Open Access Journals (Sweden)

    João Baptista dos Reis

    1979-06-01

    Full Text Available Foi feito um estudo do comportamento do líquido cefalorraquiano (LCR na cisticercose encefálica, com base em 656 observações retiradas de um material constituído por 120.000 exames de pacientes neurológicos e psiquiátricos, reunidas em 35 anos de trabalho. Com base nos casos comprovados por necrópsia ou cirurgia foram descritas as alterações do LCR. O estudo consecutivo de amostras de LCR obtidas em anos sucessivos, durante o decurso da doença, mostrou a persistência das alterações em numerosos casos, mesmo depois de 4 a 18 anos de observação. A reação de fixação de complemento para cisticerco permaneceu positiva durante todos estes anos. Foram também apreciadas as modificações do LCR em casos de cisticercose sub-cutânea e do globo ocular e em casos com cisticercos calcificados no encéfalo.

  20. Barroco: A tempestade na Biblioteca

    Directory of Open Access Journals (Sweden)

    Diego Cervelin

    2008-10-01

    Full Text Available http://dx.doi.org/10.5007/1984-784x.2008v8n12p167 Desde que Heinrich Wölfflin, nos últimos vinte anos do século XIX, se interessou por trazer à tona as formas arquitetônicas do século XVII conferindo-lhes caráter autônomo de estilo histórico determinável, não é nenhuma novidade que os estudos sobre o barroco pudessem polarizar – quase sempre em um tom colérico – os pesquisadores da arte e da cultura. Em terras do Brasil, não chega a ser de todo descabido recordar a severíssima crítica operada por Sérgio Buarque de Holanda em Raízes do Brasil. O livro, que pretende detectar a avalanche de equívocos que teria povoado o passado nacional com as vistas voltadas para a concretização de um projeto de emancipação e progresso na linha da história brasileira, apresenta em seu quarto capítulo uma impugnação explícita ao passado colonial.

  1. Barroco: A tempestade na Biblioteca

    Directory of Open Access Journals (Sweden)

    Diego Cervelin

    2008-12-01

    Full Text Available Desde que Heinrich Wölfflin, nos últimos vinte anos do século XIX, se interessou por trazer à tona as formas arquitetônicas do século XVII conferindo-lhes caráter autônomo de estilo histórico determinável, não é nenhuma novidade que os estudos sobre o barroco pudessem polarizar – quase sempre em um tom colérico – os pesquisadores da arte e da cultura. Em terras do Brasil, não chega a ser de todo descabido recordar a severíssima crítica operada por Sérgio Buarque de Holanda em Raízes do Brasil. O livro, que pretende detectar a avalanche de equívocos que teria povoado o passado nacional com as vistas voltadas para a concretização de um projeto de emancipação e progresso na linha da história brasileira, apresenta em seu quarto capítulo uma impugnação explícita ao passado colonial.

  2. Gasotransmitters: Novel regulators of epithelial Na+ transport?

    Directory of Open Access Journals (Sweden)

    Mike eAlthaus

    2012-04-01

    Full Text Available The vectorial transport of Na+ across epithelia is crucial for the maintenance of Na+ and water homeostasis in organs such as the kidneys, lung or intestine. Dysregulated Na+ transport processes are associated with various human diseases such as hypertension, the salt-wasting syndrome pseudohypoaldosteronism type 1, pulmonary edema, cystic fibrosis or intestinal disorders, which indicate that a precise regulation of epithelial Na+ transport is essential. Novel regulatory signaling molecules are gasotransmitters. There are currently three known gasotransmitters: nitric oxide (NO, carbon monoxide (CO and hydrogen sulfide (H2S. These molecules are endogenously produced in mammalian cells by specific enzymes and have been shown to regulate various physiological processes. There is a growing body of evidence, which indicates that gasotransmitters may also regulate Na+ transport across epithelia. This review will summarize the available data concerning NO, CO and H2S dependent regulation of epithelial Na+ transport processes and will discuss whether or not these mediators can be considered as true physiological regulators of epithelial Na+ transport biology.

  3. NMR studies on Na+ transport in Synechococcus PCC 6311

    Science.gov (United States)

    Nitschmann, W. H.; Packer, L.

    1992-01-01

    The freshwater cyanobacterium Synechococcus PCC 6311 is able to adapt to grow after sudden exposure to salt (NaCl) stress. We have investigated the mechanism of Na+ transport in these cells during adaptation to high salinity. Na+ influx under dark aerobic conditions occurred independently of delta pH or delta psi across the cytoplasmic membrane, ATPase activity, and respiratory electron transport. These findings are consistent with the existence of Na+/monovalent anion cotransport or simultaneous Na+/H+ +anion/OH- exchange. Na+ influx was dependent on Cl-, Br-, NO3-, or NO2-. No Na+ uptake occurred after addition of NaI, NaHCO3, or Na2SO4. Na+ extrusion was absolutely dependent on delta pH and on an ATPase activity and/or on respiratory electron transport. This indicates that Na+ extrusion via Na+/H+ exchange is driven by primary H+ pumps in the cytoplasmic membrane. Cells grown for 4 days in 0.5 m NaCl medium, "salt-grown cells," differ from control cells by a lower maximum velocity of Na+ influx and by lower steady-state ratios of [Na+]in/[Na+]out. These results indicate that cells grown in high-salt medium increase their capacity to extrude Na+. During salt adaptation Na+ extrusion driven by respiratory electron transport increased from about 15 to 50%.

  4. Na/K pump inactivation, subsarcolemmal Na measurements, and cytoplasmic ion turnover kinetics contradict restricted Na spaces in murine cardiac myocytes

    OpenAIRE

    Lu, Fang-Min; Hilgemann, Donald W.

    2017-01-01

    The Na/K pump exports cytoplasmic Na ions while importing K ions, and its activity is thought to be affected by restricted intracellular Na diffusion in cardiac myocytes. Lu and Hilgemann find instead that the pump can enter an inactivated state and that inactivation can be relieved by cytoplasmic Na.

  5. Fotokromne tiskarske barve na osnovi resorufina

    OpenAIRE

    Drnovšek, Petra

    2017-01-01

    Pametni materiali pod vplivom zunanjega dejavnika na predvidljiv in navadno uporaben način spremenijo svoje lastnosti. Takšni materiali so fotokatalitsko aktivne tiskarske barve, pri katerih se pod vplivom ultravijoličnega sevanja (v nadaljevanju UV) in/ali vidne svetlobe sproži fotokataliza, čemur sledi sprememba barve. Ena izmed možnih aplikacij fotokatalitsko aktivnih tiskarskih barv je ta, da uporabnika s spremembo barve opozarjajo na količino izpostavljenosti potencialno škodljivemu UV s...

  6. Pretpostavke za valorizaciju zapisa na elektronskim medijima

    OpenAIRE

    Eržišnik, Davorin

    1999-01-01

    U napisu se raspravlja o razlozima za valorizaciju zapisa na elektronskim medijima. Oni su ujedno i pretpostavke za tu valorizaciju, jer da bi ona uoće provodila, moraju postojati i razlozi. Istraživanje se bazira na usporedbi izmedju tih zapisa s jedne strane te klasičnih dokumenata i mikrofilmskih zapisa, s druge. Zaključuje se da u odnosu na tu drugu stranu, elektronski zapisi moraju imati i neke dodatne prednosti i kvalitete. U protivnom, ni ta valorizacija ne bi imala smisla.

  7. Naša eko hrana

    OpenAIRE

    Kelnerić, Tatjana

    2013-01-01

    Zdrav način življenja trajna je zadaća održivog razvoja i može se reći da ne postoji dobna granica za početak takvog načina života. U tom kontekstu neizbježno je da cilj svakog odgojno-obrazovnog rada, bilo da je riječ o projektu ili svakodnevici jedne odgojno-obrazovne skupine u dječjem vrtiću, mora biti usmjeren na čisto i zdravo okruženje, neposredan kontakt djeteta s prirodom, pravilnu prehranu i kretanje.

  8. VPLIV TEHNOLOŠKIH SPREMEMB NA GLOBALIZACIJO

    OpenAIRE

    Mohar, Nives

    2015-01-01

    Magistrsko delo z naslovom »Vpliv tehnoloških dejavnikov na globalizacijo« zajema dve večji področji ekonomske teorije – tehnologijo in globalizacijo. Namen magistrskega dela je analizirati odnose med tehnološkimi spremembami, gospodarsko rastjo in globaliziranostjo držav. Teoretični del smo razdelili na obravnavo tehnologije in globalizacije. Najprej smo predstavili pojme, ki se navezujejo na tehnologijo, nato smo prikazali mesto tehnologije skozi zgodovino ekonomske teorije in predstavi...

  9. Na+,K+ pumpen vedbliver at overraske

    DEFF Research Database (Denmark)

    Vilsen, Bente

    2008-01-01

    This article provides an overview of news about the Na+,K+ pump, an indispensable enzyme whose protein structure has been described in a recent article in Nature, 50 years after its discovery. In combination with mutational analysis, the structure reveals the binding pocket for the K+ ions...... and the regulation of Na+ transport by a strategically located C-terminus of the protein. Focus is also on the pathophysiology of two neurological disorders, familial hemiplegic migraine and rapid-onset dystonia-parkinsonism, recently shown to be caused by mutations in the Na+,K+-ATPase. Udgivelsesdato: may 19...

  10. Myocardial Na,K-ATPase: Clinical aspects

    Science.gov (United States)

    Kjeldsen, Keld

    2003-01-01

    The specific binding of digitalis glycosides to Na,K-ATPase is used as a tool for Na,K-ATPase quantification with high accuracy and precision. In myocardial biopsies from patients with heart failure, total Na,K-ATPase concentration is decreased by around 40%; a correlation exists between a decrease in heart function and a decrease in Na,K-ATPase concentration. During digitalization, around 30% of remaining pumps are occupied by digoxin. Myocardial Na,K-ATPase is also influenced by other drugs used for the treatment of heart failure. Thus, potassium loss during diuretic therapy has been found to reduce myocardial Na,K-ATPase, whereas angiotensin-converting enzyme inhibitors may stimulate Na,K pump activity. Furthermore, hyperaldosteronism induced by heart failure has been found to decrease Na,K-ATPase activity. Accordingly, treatment with the aldosterone antagonist, spironolactone, may also influence Na,K-ATPase activity. The importance of Na,K pump modulation with heart disease, inhibition in digitalization and other effects of medication should be considered in the context of sodium, potassium and calcium regulation. It is recommended that digoxin be administered to heart failure patients who, after institution of mortality-reducing therapy, still have heart failure symptoms, and that the therapy be continued if symptoms are revealed or reduced. Digitalis glycosides are the only safe inotropic drugs for oral use that improve hemodynamics in heart failure. An important aspect of myocardial Na,K pump affection in heart disease is its influence on extracellular potassium (Ke) homeostasis. Two important aspects should be considered: potassium handling among myocytes, and effects of potassium entering the extracellular space of the heart via the bloodstream. It should be noted that both of these aspects of Ke homeostasis are affected by regulatory aspects, eg, regulation of the Na,K pump by physiological and pathophysiological conditions, as well as by medical

  11. Prepoznavanje spolnega nadlegovanja na delovnem mestu v zdravstvu

    OpenAIRE

    Lešnik, Tina

    2013-01-01

    Diplomsko delo predstavlja problem spolnega nadlegovanja na delovnem mestu na podlagi slovenske in tuje teorije ter se osredotoča na ugotavljanje pojava spolnega nadlegovanja na delovnem mestu v zdravstvu. Izhodišča: Dosedanje raziskave nasilja in spolnega nadlegovanja na delovnem mestu kažejo, da so zdravstveni delavci le temu izpostavljeni bolj kot delavci v drugih panogah. V okviru diplomskega dela smo raziskali prepoznavanje in pojavnost spolnega nadlegovanja na delovnem mestu med štu...

  12. Glutathionylation-Dependence of Na+-K+-Pump Currents Can Mimic Reduced Subsarcolemmal Na+ Diffusion

    Science.gov (United States)

    Garcia, Alvaro; Liu, Chia-Chi; Cornelius, Flemming; Clarke, Ronald J.; Rasmussen, Helge H.

    2016-01-01

    The existence of a subsarcolemmal space with restricted diffusion for Na+ in cardiac myocytes has been inferred from a transient peak electrogenic Na+-K+ pump current beyond steady state on reexposure of myocytes to K+ after a period of exposure to K+-free extracellular solution. The transient peak current is attributed to enhanced electrogenic pumping of Na+ that accumulated in the diffusion-restricted space during pump inhibition in K+-free extracellular solution. However, there are no known physical barriers that account for such restricted Na+ diffusion, and we examined if changes of activity of the Na+-K+ pump itself cause the transient peak current. Reexposure to K+ reproduced a transient current beyond steady state in voltage-clamped ventricular myocytes as reported by others. Persistence of it when the Na+ concentration in patch pipette solutions perfusing the intracellular compartment was high and elimination of it with K+-free pipette solution could not be reconciled with restricted subsarcolemmal Na+ diffusion. The pattern of the transient current early after pump activation was dependent on transmembrane Na+- and K+ concentration gradients suggesting the currents were related to the conformational poise imposed on the pump. We examined if the currents might be accounted for by changes in glutathionylation of the β1 Na+-K+ pump subunit, a reversible oxidative modification that inhibits the pump. Susceptibility of the β1 subunit to glutathionylation depends on the conformational poise of the Na+-K+ pump, and glutathionylation with the pump stabilized in conformations equivalent to those expected to be imposed on voltage-clamped myocytes supported this hypothesis. So did elimination of the transient K+-induced peak Na+-K+ pump current when we included glutaredoxin 1 in patch pipette solutions to reverse glutathionylation. We conclude that transient K+-induced peak Na+-K+ pump current reflects the effect of conformation-dependent β1 pump subunit

  13. Altered Na+ transport after an intracellular alpha-subunit deletion reveals strict external sequential release of Na+ from the Na/K pump.

    Science.gov (United States)

    Yaragatupalli, Siddhartha; Olivera, J Fernando; Gatto, Craig; Artigas, Pablo

    2009-09-08

    The Na/K pump actively exports 3 Na(+) in exchange for 2 K(+) across the plasmalemma of animal cells. As in other P-type ATPases, pump function is more effective when the relative affinity for transported ions is altered as the ion binding sites alternate between opposite sides of the membrane. Deletion of the five C-terminal residues from the alpha-subunit diminishes internal Na(+) (Na(i)(+)) affinity approximately 25-fold [Morth et al. (2007) Nature 450:1043-1049]. Because external Na(+) (Na(o)(+)) binding is voltage-dependent, we studied the reactions involving this process by using two-electrode and inside-out patch voltage clamp in normal and truncated (DeltaKESYY) Xenopus-alpha1 pumps expressed in oocytes. We observed that DeltaKESYY (i) decreased both Na(o)(+) and Na(i)(+) apparent affinities in the absence of K(o)(+), and (ii) did not affect apparent Na(o)(+) affinity at high K(o)(+). These results support a model of strict sequential external release of Na(+) ions, where the Na(+)-exclusive site releases Na(+) before the sites shared with K(+) and the DeltaKESYY deletion only reduces Na(o)(+) affinity at the shared sites. Moreover, at nonsaturating K(o)(+), DeltaKESYY induced an inward flow of Na(+) through Na/K pumps at negative potentials. Guanidinium(+) can also permeate truncated pumps, whereas N-methyl-D-glucamine cannot. Because guanidinium(o)(+) can also traverse normal Na/K pumps in the absence of both Na(o)(+) and K(o)(+) and can also inhibit Na/K pump currents in a Na(+)-like voltage-dependent manner, we conclude that the normal pathway transited by the first externally released Na(+) is large enough to accommodate guanidinium(+).

  14. Efecto del pH en emulsiones o/w formuladas con proteína de patata y quitosano

    Directory of Open Access Journals (Sweden)

    Calero, N.

    2013-03-01

    Full Text Available Emulsions formulated with healthy ingredients are becoming increasingly popular in the developed world, due to the consumer concern about diseases related to fat and to fatty diets. This study focuses on the O/W emulsions formulated with high-oleic sunflower oil, vegetable protein (potato protein and chitosan; and deals with the role of pH in the preparation of 40 wt% high-oleic sunflower oil in water emulsions. First of all, potato protein suspensions were prepared in a pH range from 2.0 to 11.5 and enhanced protein solubility was observed with increasing pH. An increase in pH emulsion resulted in more viscoelasticity as demonstrated by the greater values for the storage and lost moduli derived from small amplitude oscillatory shear measurements as well as by the progressive change in the shape of the mechanical spectrum. Flow curves showed shear thinning properties and increasing viscosity values with pH. Z-potential measurements revealed that attractive interactions between potato protein and chitosan progressively increased with pH. The results obtained are consistent with the occurrence of a protein-polysaccharide complex around the interface of oil droplets, which yielded enhanced physical stability.

    Las emulsiones con ingredientes saludables están adquiriendo más popularidad en el mundo desarrollado, ya que el consumidor es consciente de la relación existente entre algunas enfermedades y las dietas ricas en grasas. En este trabajo se estudian emulsiones O/W formuladas con aceite de girasol alto oleico, una proteína vegetal (proteína de patata y quitosano. Concretamente, se estudia la influencia del pH en la preparación de emulsiones que contenían 40% de aceite de girasol alto oleico. Se prepararon suspensiones de la proteína en un intervalo de valores de pH comprendido entre 2 y 11,5, observándose un aumento de solubilidad de la proteína al aumentar el pH. El aumento del pH de la emulsión provocó un aumento de la

  15. Painful Na-channelopathies: an expanding universe.

    Science.gov (United States)

    Waxman, Stephen G

    2013-07-01

    The universe of painful Na-channelopathies--human disorders caused by mutations in voltage-gated sodium channels--has recently expanded in three dimensions. We now know that mutations of sodium channels cause not only rare genetic 'model disorders' such as inherited erythromelalgia and channelopathy-associated insensitivity to pain but also common painful neuropathies. We have learned that mutations of NaV1.8, as well as mutations of NaV1.7, can cause painful Na-channelopathies. Moreover, recent studies combining atomic level structural models and pharmacogenomics suggest that the goal of genomically guided pain therapy may not be unrealistic. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Erythrocyte 22Na+ influx in hypertension

    International Nuclear Information System (INIS)

    Shalev, O.; Eaton, J.W.; Ben-Ishay, D.

    1984-01-01

    We assessed 22Na+ uptake by erythrocytes (RBC) from 38 individuals with essential hypertension and 37 healthy controls. All subjects were male, white, non-obese and with normal renal function, obviating sex, race, hormonal, ponderal and renal factors known to influence RBC Na+ handling. The mean +/- sem 22Na+ uptake of the patients was 284 +/- 16 mumole/liter RBC/hour while that of normal controls was 249 +/- 11 mumole/liter RBC/hour; although the difference reached borderline significance, individual values showed considerable overlap. Consequently, in our population, RBC 22Na+ uptake is not a reliable marker for essential hypertension. We believe that previous studies should be reassessed with regard to patients' characteristics and future studies employ rigorous criteria in selection of subjects

  17. SHMUTZ & PROTON-DIAMANT H + Irradiated/Written-Hyper/Super-conductivity(HC/SC) Precognizance/Early Experiments Connections: Wet-Graphite Room-Tc & Actualized MgB2 High-Tc: Connection to Mechanical Bulk-Moduli/Hardness: Diamond Hydrocarbon-Filaments, Disorder, Nano-Powders:C,Bi,TiB2,TiC

    Science.gov (United States)

    Wunderman, Irwin; Siegel, Edward Carl-Ludwig; Lewis, Thomas; Young, Frederic; Smith, Adolph; Dresschhoff-Zeller, Gieselle

    2013-03-01

    SHMUTZ: ``wet-graphite''Scheike-....[Adv.Mtls.(7/16/12)]hyper/super-SCHMUTZ-conductor(S!!!) = ``wet''(?)-``graphite''(?) = ``graphene''(?) = water(?) = hydrogen(?) =ultra-heavy proton-bands(???) = ...(???) claimed room/high-Tc/high-Jc superconductOR ``p''-``wave''/ BAND(!!!) superconductIVITY and actualized/ instantiated MgB2 high-Tc superconductors and their BCS- superconductivity: Tc Siegel[ICMAO(77);JMMM 7,190(78)] connection to SiegelJ.Nonxline-Sol.40,453(80)] disorder/amorphous-superconductivity in nano-powders mechanical bulk/shear(?)-moduli/hardness: proton-irradiated diamond, powders TiB2, TiC,{Siegel[Semis. & Insuls.5:39,47, 62 (79)])-...``VS''/concommitance with Siegel[Phys.Stat.Sol.(a)11,45(72)]-Dempsey [Phil.Mag. 8,86,285(63)]-Overhauser-(Little!!!)-Seitz-Smith-Zeller-Dreschoff-Antonoff-Young-...proton-``irradiated''/ implanted/ thermalized-in-(optimal: BOTH heat-capacity/heat-sink & insulator/maximal dielectric-constant) diamond: ``VS'' ``hambergite-borate-mineral transformable to Overhauser optimal-high-Tc-LiBD2 in Overhauser-(NW-periodic-table)-Land: CO2/CH4-ETERNAL-sequestration by-product: WATER!!!: physics lessons from

  18. Na+-H+ exchange and Na+-dependent transport systems in streptozotocin diabetic rat kidneys

    International Nuclear Information System (INIS)

    El-Seifi, S.; Freiberg, J.M.; Kinsella, F.J.; Cheng, L.; Sacktor, B.

    1987-01-01

    The streptozotocin-induced diabetic rat was used to test the hypothesis that Na + -H + exchange activity in the proximal tubule luminal membrane would be increased in association with renal hypertrophy, altered glomerular hemodynamics, enhanced filtered load and tubular reabsorption of 22 Na + , and stimulated 22 Na= pump activity in the basolateral membrane, previously reported characteristics of this experimental animal model. Amiloride-sensitive H + gradient-dependent Na + uptake and Na + gradient-dependent H + flux were increased in brush-border membrane vesicles from the streptozotocin-treated animals. Na + gradient-dependent uptakes of phosphate, D-glucose, L-proline, and myoinositol were decreased in the drug-induced diabetic animals. These membrane transport alterations were not found when the streptozotocin-diabetic animals were treated with insulin

  19. Perfil nutricional na artrite reumatoide

    Directory of Open Access Journals (Sweden)

    Rachel Simone Maccarini Zarpellon

    2014-01-01

    Full Text Available Objetivo: Estudar o perfil nutricional de pacientes com artrite reumatoide (AR. Métodos: Estudo transversal observacional de 102 pacientes com AR. Os pacientes foram estudados para dados clínicos, demográficos, sorológicos, atividade de doença e perfil nutricional. Neste último incluiu-se a medida do índice de massa corporal (IMC, relação quadril/cintura, pregas cutâneas bicipitais (PCB e sua adequação; prega cutânea tricipital (PCT e sua adequação e circunferência muscular do braço (CMB e sua adequação. Estudos de associação foram feitos usando os testes de Fisher e qui-quadrado para dados nominais e teste t não pareado e Mann Whitney para dados numéricos. Para cálculo de correlação usou-se o teste de Spearman. Resultado: Na amostra existiam 14/102 homens e 88/102 mulheres com idade média de 52,1 ± 11,5 anos e duração média de doença de 10,6 ± 7,4 anos. A relação cintura/quadril média era de 0,92 ± 0,07. De acordo com IMC, 30,3% tinham peso normal e 65,5% tinham peso acima do normal. De acordo com PCB, 74,5% eram normais e 25,5% tinham depleção; de acordo com a PCT, 83,3% eram normais e 16,7% tinham depleção. Associação de variáveis nutricionais com gênero, fator reumatoide, nódulos e atividade da doença não mostraram diferenças (p = NS exceto, por uma relação cintura/quadril menor em indivíduos com nódulos (p = 0,02 e uma correlação modesta da PCT com a duração de doença (p = 0,02; R = 0,22; 95% IC = 0,01-0,40. Conclusão: Existe uma alta prevalência de sobrepeso e obesidade em artrite reumatoide e uma pequena frequência de depleção muscular.

  20. Glutathionylation-Dependence of Na+-K+-Pump Currents Can Mimic Reduced Subsarcolemmal Na+ Diffusion

    OpenAIRE

    Garcia, Alvaro; Liu, Chia-Chi; Cornelius, Flemming; Clarke, Ronald?J.; Rasmussen, Helge?H.

    2016-01-01

    The existence of a subsarcolemmal space with restricted diffusion for Na+ in cardiac myocytes has been inferred from a transient peak electrogenic Na+-K+ pump current beyond steady state on reexposure of myocytes to K+ after a period of exposure to K+-free extracellular solution. The transient peak current is attributed to enhanced electrogenic pumping of Na+ that accumulated in the diffusion-restricted space during pump inhibition in K+-free extracellular solution. However, there are no know...

  1. Theoretical study of Na(4p2P)+Na(3s2S) and Cd(5p3P0)+Na(3s2S) collisions and their role in the energy transfer between Cd* and Na

    International Nuclear Information System (INIS)

    Magnier, S.; Pisa Univ.; Angeli, C.; Granucci, G.; Masnou-Seeuws, F.; Allegrini, M.; Pisa Univ.; Persico, M.

    1997-01-01

    We have computed the cross sections for the energy transfer process Cd(5p 3 P 0 ) + Na(3s 2 S) →Cd(5s 1 S) + Na(4p 2 P) and for the state changing collision Na(4p 2 P) + Na(3s 2 S)→Na(3d 2 D) + Na(3s 2 S), based on theoretical interaction potentials for the NaCd and Na 2 systems, respectively. Our calculations shed light on the interpretation of experiments with laser excited Na+Cd vapour mixtures. It turns out that Cd(5p 3 P 0 ), in rapid equilibrium with the doorway state Cd(5p 3 P 1 ), efficiently transfers energy to Na, populating the 4p 2 P state. The collisions with ground state Na cause a very fast conversion of the 4p 2 P to the 3d 2 D state, from which the strongest emission is observed. (orig.)

  2. Suppression of Na interstitials in Na-F codoped ZnO

    Science.gov (United States)

    Huo, Wenxing; Mei, Zengxia; Tang, Aihua; Liang, Huili; Du, Xiaolong

    2018-04-01

    Controlling the formation of interstitial Na (Nai) self-compensating defects has been a long-term physics problem for effective Na doping in ZnO. Herein, we present an experimental approach to the suppression of Nai defects in ZnO via Na and F codoping under an oxygen-rich condition during the molecular beam epitaxy growth process. It is found that the incorporation of such large numbers of Na and F dopants (˜1020 cm-3) does not cause an obvious influence on the lattice parameters. Hall-effect measurements demonstrate that F doping efficiently raises the Fermi level (EF) of ZnO films, which is expected to make the formation energy of Nai and NaZn increase and decrease, respectively. Most of the Na atoms occupy the substitutional Zn sites, and the formation of Nai is suppressed consequently. Secondary ion mass spectrometry measurements reveal that F and Na atoms are tightly bonded together due to their strong Coulomb interaction. The enhanced deep level emission (DLE) in ZnO:Na-F is ascribed to the considerable amount of isolated Zn vacancy (VZn) defects induced by the elevated EF and the formation of neutral (" separators="| FO + - Na Zn - ) 0 complexes. On the other hand, formation of (" separators="| FO + - VZn 2 - ) - complexes in ZnO:F exhausts most of the isolated Zn vacancies, leading to the disappearance of the DLE band.

  3. Absolute quantification of Na + bound fraction by double-quantum filtered 23Na NMR spectroscopy

    Science.gov (United States)

    Mouaddab, Mohamed; Foucat, Loïc; Donnat, Jean Pierre; Renou, Jean Pierre; Bonny, Jean Marie

    2007-11-01

    A method is described for the absolute quantification of double-quantum filtered spectra of spin-3/2 nuclei ( 23Na). The method was tested on a model system, a cationic exchange resin for which the number of Na + binding sites was quantitatively controlled. The theoretical and experimental approaches were validated on samples with different Na + concentrations. An excellent agreement between the results obtained by double-quantum and single-quantum acquisitions was found. This method paves the way for absolute quantification of both bound and free fractions of Na +, which are determining factors in the characterization of salted/brined/dried food products.

  4. Interaction between Na+/K+-pump and Na+/Ca2+-exchanger modulates intercellular communication.

    Science.gov (United States)

    Matchkov, Vladimir V; Gustafsson, Helena; Rahman, Awahan; Briggs Boedtkjer, Donna M; Gorintin, Sarah; Hansen, Anne Kirstine; Bouzinova, Elena V; Praetorius, Helle A; Aalkjaer, Christian; Nilsson, Holger

    2007-04-13

    Ouabain, a specific inhibitor of the Na(+)/K(+)-pump, has previously been shown to interfere with intercellular communication. Here we test the hypothesis that the communication between vascular smooth muscle cells is regulated through an interaction between the Na(+)/K(+)-pump and the Na(+)/Ca(2+)-exchanger leading to an increase in the intracellular calcium concentration ([Ca(2+)](i)) in discrete areas near the plasma membrane. [Ca(2+)](i) in smooth muscle cells was imaged in cultured rat aortic smooth muscle cell pairs (A7r5) and in rat mesenteric small artery segments simultaneously with force. In A7r5 coupling between cells was estimated by measuring membrane capacitance. Smooth muscle cells were uncoupled when the Na(+)/K(+)-pump was inhibited either by a low concentration of ouabain, which also caused a localized increase of [Ca(2+)](i) near the membrane, or by ATP depletion. Reduction of Na(+)/K(+)-pump activity by removal of extracellular potassium ([K(+)](o)) also uncoupled cells, but only after inhibition of K(ATP) channels. Inhibition of the Na(+)/Ca(2+)-exchange activity by SEA0400 or by a reduction of the equilibrium potential (making it more negative) also uncoupled the cells. Depletion of intracellular Na(+) and clamping of [Ca(2+)](i) at low concentrations prevented the uncoupling. The experiments suggest that the Na(+)/K(+)-pump may affect gap junction conductivity via localized changes in [Ca(2+)](i) through modulation of Na(+)/Ca(2+)-exchanger activity.

  5. HCO3(-)-coupled Na+ influx is a major determinant of Na+ turnover and Na+/K+ pump activity in rat hepatocytes

    International Nuclear Information System (INIS)

    Fitz, J.G.; Lidofsky, S.D.; Weisiger, R.A.; Xie, M.H.; Cochran, M.; Grotmol, T.; Scharschmidt, B.F.

    1991-01-01

    Recent studies in hepatocytes indicate that Na(+)-coupled HCO3- transport contributes importantly to regulation of intracellular pH and membrane HCO3- transport. However, the direction of net coupled Na+ and HCO3- movement and the effect of HCO3- on Na+ turnover and Na+/K+ pump activity are not known. In these studies, the effect of HCO3- on Na+ influx and turnover were measured in primary rat hepatocyte cultures with 22Na+, and [Na+]i was measured in single hepatocytes using the Na(+)-sensitive fluorochrome SBFI. Na+/K+ pump activity was measured in intact perfused rat liver and hepatocyte monolayers as Na(+)-dependent or ouabain-suppressible 86Rb uptake, and was measured in single hepatocytes as the effect of transient pump inhibition by removal of extracellular K+ on membrane potential difference (PD) and [Na+]i. In hepatocyte monolayers, HCO3- increased 22Na+ entry and turnover rates by 50-65%, without measurably altering 22Na+ pool size or cell volume, and HCO3- also increased Na+/K+ pump activity by 70%. In single cells, exposure to HCO3- produced an abrupt and sustained rise in [Na+]i from approximately 8 to 12 mM. Na+/K+ pump activity assessed in single cells by PD excursions during transient K+ removal increased congruent to 2.5-fold in the presence of HCO3-, and the rise in [Na+]i produced by inhibition of the Na+/K+ pump was similarly increased congruent to 2.5-fold in the presence of HCO3-. In intact perfused rat liver, HCO3- increased both Na+/K+ pump activity and O2 consumption. These findings indicate that, in hepatocytes, net coupled Na+ and HCO3- movement is inward and represents a major determinant of Na+ influx and Na+/K+ pump activity. About half of hepatic Na+/K+ pump activity appears dedicated to recycling Na+ entering in conjunction with HCO3- to maintain [Na+]i within the physiologic range

  6. Clues to NaCN formation

    Science.gov (United States)

    Quintana-Lacaci, G.; Cernicharo, J.; Velilla Prieto, L.; Agúndez, M.; Castro-Carrizo, A.; Fonfría, J. P.; Massalkhi, S.; Pardo, J. R.

    2017-11-01

    Context. ALMA is providing us essential information on where certain molecules form. Observing where these molecules emission arises from, the physical conditions of the gas, and how this relates with the presence of other species allows us to understand the formation of many species, and to significantly improve our knowledge of the chemistry that occurs in the space. Aims: We studied the molecular distribution of NaCN around IRC +10216, a molecule detected previously, but whose origin is not clear. High angular resolution maps allow us to model the abundance distribution of this molecule and check suggested formation paths. Methods: We modeled the emission of NaCN assuming local thermal equilibrium (LTE) conditions. These profiles were fitted to azimuthal averaged intensity profiles to obtain an abundance distribution of NaCN. Results: We found that the presence of NaCN seems compatible with the presence of CN, probably as a result of the photodissociation of HCN, in the inner layers of the ejecta of IRC +10216. However, similar as for CH3CN, current photochemical models fail to reproduce this CN reservoir. We also found that the abundance peak of NaCN appears at a radius of 3 × 1015 cm, approximately where the abundance of NaCl, suggested to be the parent species, starts to decay. However, the abundance ratio shows that the NaCl abundance is lower than that obtained for NaCN. We expect that the LTE assumption might result in NaCN abundances higher than the real ones. Updated photochemical models, collisional rates, and reaction rates are essential to determine the possible paths of the NaCN formation. Based on observations carried out with ALMA and the IRAM 30 m Telescope. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada) and NSC and ASIAA (Taiwan), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. IRAM is supported by INSU/CNRS (France

  7. Quasi–solid state rechargeable Na-CO2 batteries with reduced graphene oxide Na anodes

    Science.gov (United States)

    Hu, Xiaofei; Li, Zifan; Zhao, Yaran; Sun, Jianchao; Zhao, Qing; Wang, Jianbin; Tao, Zhanliang; Chen, Jun

    2017-01-01

    Na-CO2 batteries using earth-abundant Na and greenhouse gas CO2 are promising tools for mobile and stationary energy storage, but they still pose safety risks from leakage of liquid electrolyte and instability of the Na metal anode. These issues result in extremely harsh operating conditions of Na-CO2 batteries and increase the difficulty of scaling up this technology. We report the development of quasi–solid state Na-CO2 batteries with high safety using composite polymer electrolyte (CPE) and reduced graphene oxide (rGO) Na anodes. The CPE of PVDF-HFP [poly(vinylidene fluoride-co-hexafluoropropylene)]–4% SiO2/NaClO4–TEGDME (tetraethylene glycol dimethyl ether) has high ion conductivity (1.0 mS cm−1), robust toughness, a nonflammable matrix, and strong electrolyte-locking ability. In addition, the rGO-Na anode presents fast and nondendritic Na+ plating/stripping (5.7 to 16.5 mA cm−2). The improved kinetics and safety enable the constructed rGO-Na/CPE/CO2 batteries to successfully cycle in wide CO2 partial pressure window (5 to 100%, simulated car exhaust) and especially to run for 400 cycles at 500 mA g−1 with a fixed capacity of 1000 mA·hour g−1 in pure CO2. Furthermore, we scaled up the reversible capacity to 1.1 A·hour in pouch-type batteries (20 × 20 cm, 10 g, 232 Wh kg−1). This study makes quasi–solid state Na-CO2 batteries an attractive prospect. PMID:28164158

  8. Kupokelewa Zaidi Kwa Simu Ya Mkononi Kuliko Kompyuta Na ...

    African Journals Online (AJOL)

    Mtandao wa tovuti ni nyenzo ya msingi katika maendeleo ya uwanja wa mawasiliano unaounganisha watu na jamii mbalimbali katika ulimwengu wa leo unaotandawaa. Katika “ulimwengu wa kwanza na wa pili”, yaani mabara ya Amerika, Uropa na Asia, maendeleo na mapinduzi makubwa katika uwanja wa teknolojia ya ...

  9. Effects of different NaCl Concentrations on germination and ...

    African Journals Online (AJOL)

    Growth was steadily stimulated in both species at lower NaCl levels with best growth stimulation at 50 mM NaCl but was adversely affected by higher NaCl concentration levels (75, 100 and 150 mM). Both species ... Key words: Germination, early seedling growth, NaCl, salinity, Amaranthus hybridus, Celosia argentea.

  10. Ujanibishaji wa Office 2003 na Windows XP kwa Kiswahili Sanifu ...

    African Journals Online (AJOL)

    Mradi wa ujanibishaji wa Office 2003 na Windows XP kwa Kiswahili sanifu ulitekelezwa katika kipindi 2004-2005. Malengo ya mradi yalikuwa: (1) kuandaa istilahi za kompyuta kwa Kiingereza-Kiswahili, na (2) kutafsiri programu nne za kawaida za Office (Outlook, Excel, Word na PowerPoint) na Windows XP. Makala hii ina ...

  11. Mabadiliko Ya Kifonolojia Na Kimofolojia Wakati Wa Utohozi Wa ...

    African Journals Online (AJOL)

    Mwingiliano wa lugha ya Kiswahili na Kiarabu una historia ndefu kidogo. Inasemekana Waarabu walianza muwasala na 'Waswahili' tangu karne ya kwanza (BK) (Polome 1967:9). Kutokana na muwasala huo wa muda mrefu, lugha hizi mbili (Kiarabu na Kiswahili) zimeathiriana sana. Lakini kuna maoni kwamba Kiarabu ...

  12. Utata kuhusu Dhana na Chimbuko la Wahadimu katika Kisiwa cha ...

    African Journals Online (AJOL)

    Data za makala haya zimepatikana kupitia usaili na majadiliano ya majopo ya wazungumzaji wa Kimakunduchi na Unguja na kujadili kwa muhtasari chimbuko la Wahadimu. Kwa muda mrefu dhana ya Wahadimu imekuwa ikijadiliwa kwa mitazamo tofautitofauti kama inavyobainishwa na wataalamu mbalimbali wakiwemo ...

  13. O Passeio Público do Rio de Janeiro na Literatura, na Pintura e na Fotografia do Século XIX

    Directory of Open Access Journals (Sweden)

    Solange de Aragão

    2012-06-01

    Full Text Available Este artigo tem como objetivo geral e mais amplo chamar a atenção dos pesquisadores para a importância da literatura, da pintura e da fotografia como fontes documentais para a construção da História do Paisagismo no Brasil por meio de um estudo de caso muito particular: o Passeio Público do Rio de Janeiro no século XIX. São objetivos específicos apresentar e analisar o modo como esse espaço livre público aparece na literatura, na pintura e na fotografia desse período, considerando suas transformações paisagísticas.

  14. Muziki wa Hip Hop na Haki Za Kijamii: Dhima, Changamoto na ...

    African Journals Online (AJOL)

    Ni dhahiri kuwa haki za kijamii zinaweza kuwasilishwa kwa jamii pana kupitia sanaa ya hip hop. Makala haya basi, yanabainisha dhima na mchango wa muziki wa hip hop katika masuala ya haki za kijamii, yanafafanua changamoto za muziki huu katika kuwasilisha haki za kijamii na kutoa mapendekezo kwa makundi ...

  15. Regeneration of plantlets under NaCl stress from NaN3 treated ...

    African Journals Online (AJOL)

    In this experiment, mutation induction in explants using NaN3 and subsequently, callus growth and plant regeneration under NaCl stressed conditions was assessed in some sugarcane (Saccharum officinarum L.) cultivars (Thatta-10, CPF-237 and SPHS-19). Immature bases of leaf tips were cultured on MS2n (MS salts, 3.0 ...

  16. Molecular dynamics investigation of Na+ in Na2Ni2TeO6

    International Nuclear Information System (INIS)

    Sau, Kartik; Kumar, P. Padma

    2014-01-01

    An inter-atomic potential for Na 2 Ni 2 TeO 6 in the Parrinello- Rahman-Vashishta (PRV) model is parameterized empirically. The potential reproduces variety of structural and transport properties of that material in good agreement with recent experimental results. The study provides fresh insights on the migration channels and mechanism of Na + in the system

  17. NaI(Tl) electron energy resolution

    CERN Document Server

    Mengesha, W

    2002-01-01

    NaI(Tl) electron energy resolution eta sub e was measured using the Modified Compton Coincidence Technique (MCCT). The MCCT allowed detection of nearly monoenergetic internal electrons resulting from the scattering of incident 662 keV gamma rays within a primary NaI(Tl) detector. Scattered gamma rays were detected using a secondary HPGe detector in a coincidence mode. Measurements were carried out for electron energies ranging from 16 to 438 keV, by varying the scattering angle. Measured HPGe coincidence spectra were deconvolved to determine the scattered energy spectra from the NaI(Tl) detector. Subsequently, the NaI(Tl) electron energy spectra were determined by subtracting the energy of scattered spectra from the incident source energy (662 keV). Using chi-squared minimization, iterative deconvolution of the internal electron energy spectra from the measured NaI(Tl) spectra was then used to determine eta sub e at the electron energy of interest. eta sub e values determined using this technique represent va...

  18. Na/K pump inactivation, subsarcolemmal Na measurements, and cytoplasmic ion turnover kinetics contradict restricted Na spaces in murine cardiac myocytes.

    Science.gov (United States)

    Lu, Fang-Min; Hilgemann, Donald W

    2017-07-03

    Decades ago, it was proposed that Na transport in cardiac myocytes is modulated by large changes in cytoplasmic Na concentration within restricted subsarcolemmal spaces. Here, we probe this hypothesis for Na/K pumps by generating constitutive transsarcolemmal Na flux with the Na channel opener veratridine in whole-cell patch-clamp recordings. Using 25 mM Na in the patch pipette, pump currents decay strongly during continuous activation by extracellular K (τ, ∼2 s). In contradiction to depletion hypotheses, the decay becomes stronger when pump currents are decreased by hyperpolarization. Na channel currents are nearly unchanged by pump activity in these conditions, and conversely, continuous Na currents up to 0.5 nA in magnitude have negligible effects on pump currents. These outcomes are even more pronounced using 50 mM Li as a cytoplasmic Na congener. Thus, the Na/K pump current decay reflects mostly an inactivation mechanism that immobilizes Na/K pump charge movements, not cytoplasmic Na depletion. When channel currents are increased beyond 1 nA, models with unrestricted subsarcolemmal diffusion accurately predict current decay (τ ∼15 s) and reversal potential shifts observed for Na, Li, and K currents through Na channels opened by veratridine, as well as for Na, K, Cs, Li, and Cl currents recorded in nystatin-permeabilized myocytes. Ion concentrations in the pipette tip (i.e., access conductance) track without appreciable delay the current changes caused by sarcolemmal ion flux. Importantly, cytoplasmic mixing volumes, calculated from current decay kinetics, increase and decrease as expected with osmolarity changes (τ >30 s). Na/K pump current run-down over 20 min reflects a failure of pumps to recover from inactivation. Simulations reveal that pump inactivation coupled with Na-activated recovery enhances the rapidity and effectivity of Na homeostasis in cardiac myocytes. In conclusion, an autoregulatory mechanism enhances cardiac Na/K pump activity when

  19. Anion-coupled Na efflux mediated by the human red blood cell Na/K pump

    International Nuclear Information System (INIS)

    Dissing, S.; Hoffman, J.F.

    1990-01-01

    The red cell Na/K pump is known to continue to extrude Na when both Na and K are removed from the external medium. Because this ouabain-sensitive flux occurs in the absence of an exchangeable cation, it is referred to as uncoupled Na efflux. This flux is also known to be inhibited by 5 mM Nao but to a lesser extent than that inhibitable by ouabain. Uncoupled Na efflux via the Na/K pump therefore can be divided into a Nao-sensitive and Nao-insensitive component. We used DIDS-treated, SO4-equilibrated human red blood cells suspended in HEPES-buffered (pHo 7.4) MgSO4 or (Tris)2SO4, in which we measured 22Na efflux, 35SO4 efflux, and changes in the membrane potential with the fluorescent dye, diS-C3 (5). A principal finding is that uncoupled Na efflux occurs electroneurally, in contrast to the pump's normal electrogenic operation when exchanging Nai for Ko. This electroneutral uncoupled efflux of Na was found to be balanced by an efflux of cellular anions. (We were unable to detect any ouabain-sensitive uptake of protons, measured in an unbuffered medium at pH 7.4 with a Radiometer pH-STAT.) The Nao-sensitive efflux of Nai was found to be 1.95 +/- 0.10 times the Nao-sensitive efflux of (SO4)i, indicating that the stoichiometry of this cotransport is two Na+ per SO4=, accounting for 60-80% of the electroneutral Na efflux. The remainder portion, that is, the ouabain-sensitive Nao-insensitive component, has been identified as PO4-coupled Na transport and is the subject of a separate paper. That uncoupled Na efflux occurs as a cotransport with anions is supported by the result, obtained with resealed ghosts, that when internal and external SO4 was substituted by the impermeant anion, tartrate i,o, the efflux of Na was inhibited 60-80%. This inhibition could be relieved by the inclusion, before DIDS treatment, of 5 mM Cli,o

  20. Metallic Na formation in NaCl crystals with irradiation of electron or vacuum ultraviolet photon

    Energy Technology Data Exchange (ETDEWEB)

    Owaki, Shigehiro [Osaka Prefecture Univ., Sakai, Osaka (Japan). Coll. of Integrated Arts and Sciences; Koyama, Shigeko; Takahashi, Masao; Kamada, Masao; Suzuki, Ryouichi

    1997-03-01

    Metallic Na was formed in NaCl single crystals with irradiation of a variety of radiation sources and analyzed the physical states with several methods. In the case of irradiation of 21 MeV electron pulses to the crystal blocks, the optical absorption and lifetime measurement of positron annihilation indicated appearance of Na clusters inside. Radiation effects of electron beam of 30 keV to the crystals in vacuum showed the appearance of not only metallic Na but atomic one during irradiation with Auger electron spectroscopy. Intense photon fluxes in vacuum ultraviolet region of synchrotron radiation were used as another source and an analyzing method of ultraviolet photoelectron spectroscopy. The results showed the metallic Na layered so thick that bulk plasmon can exist. (author)

  1. Hydrolysis of Rice Straw Pretreated by Na2SO3 Over Fe-resin/NaCl

    Directory of Open Access Journals (Sweden)

    YANG Hui

    2017-05-01

    Full Text Available To increase the conversion of rice straw(RS and the yield of products, we employed three methods, which were ultrasonic wave, steam explosion and Na2SO3 pretreatment to pretreat RS(the treated RS noted as CS-RS, ZQ-RS and Na2SO3-RS, respectively and found that Na2SO3 treatment was the best pretreatment method based on XRD, SEM, elemental analysis and content of cellulose, hemicellulose and lignin. The conversion of Na2SO3-RS and the yield of total reducing sugar(TRS and levulinic acid(LA were 97.3%, 29.6% and 13.5%, respectively by 10% Fe-resin in 3.3% NaCl solution under 200 ℃.

  2. Muscle K+, Na+, and Cl- disturbances and Na+-K+ pump inactivation: implications for fatigue

    DEFF Research Database (Denmark)

    McKenna, Michael J; Bangsbo, Jens; Renaud, Jean-Marc

    2008-01-01

    (+)-ATPase activity during exercise stabilizes Na(+) and K(+) concentration gradients and membrane excitability and thus protects against fatigue. However, during intense contraction some Na(+)-K(+) pumps are inactivated and together with further ionic disturbances, likely precipitate muscle fatigue.......Membrane excitability is a critical regulatory step in skeletal muscle contraction and is modulated by local ionic concentrations, conductances, ion transporter activities, temperature, and humoral factors. Intense fatiguing contractions induce cellular K(+) efflux and Na(+) and Cl(-) influx......, causing pronounced perturbations in extracellular (interstitial) and intracellular K(+) and Na(+) concentrations. Muscle interstitial K(+) concentration may increase 1- to 2-fold to 11-13 mM and intracellular K(+) concentration fall by 1.3- to 1.7-fold; interstitial Na(+) concentration may decline by 10 m...

  3. Osmotic and ionic effects of NaCl and Na2SO4 salinity on Phragmites australis

    DEFF Research Database (Denmark)

    Pagter, Majken; Bragato, Claudia; Malagoli, Mario

    2009-01-01

    and partly Cl ions from the leaves. Incomplete exclusion of Cl from the leaves may affect aboveground biomass production, which was significantly more reduced by NaCl than Na2SO4. Stomatal conductance was negatively influenced by decreasing water potentials caused by NaCl or Na2SO4, implying that a non...

  4. Structure-function relationships of Na+, K+, ATP, or Mg2+ binding and energy transduction in Na,K-ATPase

    DEFF Research Database (Denmark)

    Jorgensen, Peter L.; Pedersen, Per Amstrup

    2000-01-01

    Na,K-ATPase; Mutagenesis; Na+ binding; K+ binding; Tl+ binding; Mg2+ binding; ATP binding; Cation binding site; Energy transduction......Na,K-ATPase; Mutagenesis; Na+ binding; K+ binding; Tl+ binding; Mg2+ binding; ATP binding; Cation binding site; Energy transduction...

  5. Long-Range Effects of Na(+) Binding in Na,K-ATPase Reported by ATP.

    Science.gov (United States)

    Middleton, David A; Fedosova, Natalya U; Esmann, Mikael

    2015-12-01

    This paper addresses the question of long-range interactions between the intramembranous cation binding sites and the cytoplasmic nucleotide binding site of the ubiquitous ion-transporting Na,K-ATPase using (13)C cross-polarization magic-angle spinning (CP-MAS) solid-state nuclear magnetic resonance. High-affinity ATP binding is induced by the presence of Na(+) as well as of Na-like substances such as Tris(+), and these ions are equally efficient promoters of nucleotide binding. CP-MAS analysis of bound ATP with Na,K-ATPase purified from pig kidney membranes reveals subtle differences in the nucleotide interactions within the nucleotide site depending on whether Na(+) or Tris(+) is used to induce binding. Differences in chemical shifts for ATP atoms C1' and C5' observed in the presence of Na(+) or Tris(+) suggest alterations in the residues surrounding the bound nucleotide, hydrogen bonding, and/or conformation of the ribose ring. This is taken as evidence of a long-distance communication between the Na(+)-filled ion sites in the membrane interior and the nucleotide binding site in the cytoplasmic domain and reflects the first conformational change ultimately leading to phosphorylation of the enzyme. Stopped-flow fluorescence measurements with the nucleotide analogue eosin show that the dissociation rate constant for eosin is larger in Tris(+) than in Na(+), giving kinetic evidence of the difference in structural effects of Na(+) and Tris(+). According to the recent crystal structure of the E1·AlF4(-)·ADP·3Na(+) form, the coupling between the ion binding sites and the nucleotide side is mediated by, among others, the M5 helix.

  6. Eletrencefalograma na síndrome parkinsoniana

    Directory of Open Access Journals (Sweden)

    José Geraldo Camargo Lima

    1973-09-01

    Full Text Available Foram estudados os eletrencefalogramas de 50 pacientes parkinsonianos livres de qualquer antecedente convulsivo, sendo registrados traçados anormais em 40% dos casos. A incidência de traçados anormais foi maior na síndrome parkinsoniana bilateral do que na unilateral (52% e 25%, respectivamente. Entre as anormalidades assinaladas foram as paroxísticas as mais freqüentes (65% dos casos, caracterizando-se predominantemente por surtos de ondas teta. O registro de anormalidades paroxísticas do tipo irritativo encontrado em três casos é salientado. Alterações da atividade de base foram assinaladas em 35% dos pacientes. A idade dos pacientes não parece ter tido importante papel na gênese das anormalidades eletrencefalográficas.

  7. Knjige o kartografskim projekcijama na internetu

    Directory of Open Access Journals (Sweden)

    Nedjeljko Frančula

    2011-12-01

    Full Text Available U ovom prikazu skrećemo pozornost na neke knjige o kartografskim projekcijama koje su prvobitno objavljene u tisku, a potom digitalizirane i besplatno stavljene na mrežu. Neke od tih knjiga nude se na mreži kao Google e-knjige. Google godinama skuplja knjige kojima su istekla autorska prava i digitalizira ih. Fotografira se svaka stranica te zatim spaja u jednu veliku fotografiju iz koje se izvlači tekst softverom OCR. Google čuva originalnu digitalnu fotografiju u svom arhivu, a izvučeni tekst pretvara u formate HTML, PDF ili EPUB. Google danas nudi više od milijun besplatnih e-knjiga (http://www.google.com/books.

  8. Tecnologia simplificada na enfermagem materno infantil

    Directory of Open Access Journals (Sweden)

    Selma Campestrini

    1991-09-01

    Full Text Available A autora apresenta três modelos de tecnologia simplificada da enfermagem materno infantil: o equipamento didático SEIO COBAIA para treinar exercícios e massagens da mama e mamilo; a peça indumentária SUPRETRAUMA - sutiã preventivo de traumatismo mamilar - usado por gestantes; e, a técnica para reverter mamilo umbilicado durante o puerperio imediato. Além de corroborar na promoção do aleitamento materno e na prevenção de desmame precoce, demonstra a possibilidade da enfermagem relacionar o saber teórico-científico com o saber tecnico-prático, na saúde da mulher e da criança, com tecnologia adequada às necessidades, à compreensão e ao bem estar da população.

  9. Hidroginástica na terceira idade

    OpenAIRE

    Paula, Karla Campos de; Paula, Débora Campos de

    1998-01-01

    O processo de envelhecimento no indivíduo saudável está relacionado com inúmeras alterações psicológicas e físicas que interferem na área motora, concorrendo para a inatividade e contribuindo para o aparecimento e agravamento de determinadas doenças, além de influenciar negativamente a realização das atividades de vida diária. Portanto, a prática de atividade física é fundamental para o idoso, não só na prevenção de doenças como na reabilitação de suas habilidades motoras, promovendo um estil...

  10. Labirintos na cidade contemporânea

    Directory of Open Access Journals (Sweden)

    Edson Luiz André de Sousa

    Full Text Available Este artigo pretende tensionar pontos de conexão e diluição de fronteiras entre as categorias público/privado, conversando com a literatura de Baudelaire e W. Benjamin, Fredric Jamenson e Marc Augé. Através da imagem do labirinto, símbolo da cidade antiga que se quis extinguir na cidade moderna, busca-se refletir sobre alguns caminhos e caminhantes considerados excedentes na cidade contemporânea. O cenário propulsor dessa reflexão é a experiência do jornal Boca de Rua, elaborado por moradores de rua na cidade de Porto Alegre.

  11. Crystal structure of a Na+-bound Na+,K+-ATPase preceding the E1P state.

    Science.gov (United States)

    Kanai, Ryuta; Ogawa, Haruo; Vilsen, Bente; Cornelius, Flemming; Toyoshima, Chikashi

    2013-10-10

    Na(+),K(+)-ATPase pumps three Na(+) ions out of cells in exchange for two K(+) taken up from the extracellular medium per ATP molecule hydrolysed, thereby establishing Na(+) and K(+) gradients across the membrane in all animal cells. These ion gradients are used in many fundamental processes, notably excitation of nerve cells. Here we describe 2.8 Å-resolution crystal structures of this ATPase from pig kidney with bound Na(+), ADP and aluminium fluoride, a stable phosphate analogue, with and without oligomycin that promotes Na(+) occlusion. These crystal structures represent a transition state preceding the phosphorylated intermediate (E1P) in which three Na(+) ions are occluded. Details of the Na(+)-binding sites show how this ATPase functions as a Na(+)-specific pump, rejecting K(+) and Ca(2+), even though its affinity for Na(+) is low (millimolar dissociation constant). A mechanism for sequential, cooperative Na(+) binding can now be formulated in atomic detail.

  12. A perda de chance na responsabilidade civil

    OpenAIRE

    Silva, Rute Eunice Andrade Teixeira da

    2017-01-01

    Resumo: O presente trabalho tem como objecto de estudo a teoria da perda de chance. Tema ainda controverso tanto na doutrina como na jurisprudência, urge fazer-se uma análise do mesmo no âmbito do direito português. Para um melhor entendimento sobre a figura da perda de chance, é necessário ter presente alguns aspectos do instituto da responsabilidade civil. Será realizada uma análise geral dos pressupostos da responsabilidade civil, versando-nos principalmente sobre o dano e o ne...

  13. O trabalho na África subsariana

    OpenAIRE

    Carneiro, Emmanuel Moreira

    2008-01-01

    A natureza do trabalho e do mercado de emprego na África subsariana está intrinsecamente ligado ao tipo de produção material dominante, à natureza das relações de produção estabelecidas, bem como ao inerente sistema de formação e distribuição do rendimento. É ainda profundamente condicionada pela evolução do processo de estruturação mundial do capitalismo, o qual se traduz, na fase actual, pelo que se convencionou designar mundialização e globalização.

  14. A TEOLOGIA LATINO-AMERICANA NA ENCRUZILHADA

    Directory of Open Access Journals (Sweden)

    Victor Codina

    1999-01-01

    Full Text Available As mudanças ocorridas no mundo, no fim dos anos 80, não podem deixar de afetar a Teologia latino-americana e, muito concretamente, a Teologia da Libertação (TdL, teologia que nasceu na América Latina na década de 701. A TdL encontra-se hoje numa encruzilhada: retroceder e dar marcha a ré? Continuar repetindo o que até agora foi dito, como se nada tivesse acontecido?

  15. A Imagem como Ruína

    Directory of Open Access Journals (Sweden)

    Míriam Volpe

    2001-12-01

    Full Text Available O dialogismo ente o filme Citizen Kane, de Orson Welles, e o poema “Kubla Khan”, de S.T. Coleridgé, é analisado, sendo evidenciados não só o tema em comum – o mito do Paraíso perdido – como também a similariedade na organização do disurso na justaposição das images, como fragmentos da memória a serem preservados.

  16. Sexualidade na velhice e qualidade de vida

    OpenAIRE

    Viana, Helena Brandão; Madruga, Vera Aparecida

    2010-01-01

    O objetivo deste trabalho, realizado por meio de uma revisão de literatura, foi abordar uma revisão literária sobre a influência da sexualidade na qualidade de vida deidosos, temática pouco discutida nas diferentes áreas de pesquisas sobre envelhecimento. Diante da escassez de bibliografia na cultura brasileira, apresentou-se uma revisão de literatura sobre envelhecimento junto à temática da sexualidade, trazendo uma trajetória histórica sobre estudos de sexualidade ao longo do tempo, discuti...

  17. E-GRADIVA NA PRIMERU OBRAVNAVE GLAGOLA

    OpenAIRE

    Kajtna, Tjaša

    2013-01-01

    Sodobne tehnologije so korenito spremenile današnji način življenja. Tako je tudi z izobraževanjem. Vedno več učiteljev ob klasičnih metodah poučevanja uporablja tudi nove pristope, ki so povezani s sodobnimi tehnologijami. V diplomskem delu je opredeljeno e-izobraževanje, predstavljene so nove tehnologije, ki se pojavljajo v povezavi z le-tem. V nadaljevanju sledi teoretična obravnava e-gradiv, ki ob podpori informacijsko komunikacijskih tehnologij predstavljajo temelj e-izobraževanja. ...

  18. ANALIZA IZGUB NA OSLABLJENEM PRENAPETOSTNEM ODVODNIKU

    OpenAIRE

    Ajdnik, Miran

    2011-01-01

    Diplomska naloga obravnava problematiko izgub električne energije na oslabljenem prenapetostnem odvodniku na transformatorski postaji Kot-Makej (0,95/0,4 kV) in neozemljenem izvoru. Omenjena transformatorska postaja se napaja iz razdelilne transformatorske postaje Ravne (RTP RAVNE) preko 20 kV daljnovoda Mežica in transformatorske postaje Kot (20/0,95/0,4 kV). Rešitev je predstavljena s programskim orodjem MATLAB/Simulink iz knjižnice PowerSystem, s katerim je izvedena simulacija pri oslablje...

  19. Vpliv tripsinizacije na celice Caco-2.

    OpenAIRE

    Cuculić, Nika

    2018-01-01

    Caco-2 celična linija se uporablja v številnih predkliničnih raziskavah. Ena izmed najbolj izraženih lastnosti celične linije Caco-2 je njihova zmožnost spontane diferenciacije. Zaradi različnega rokovanja s celično linijo Caco-2 med laboratoriji, v kar spada tudi uporaba različnih koncentracij tripsina ter čas izpostavljenosti celic tripsinu, se rezultati raziskav med laboratoriji lahko zelo razlikujejo in niso primerljivi. Preverili smo vpliv različnih koncentracij tripsina na celično viabi...

  20. Izbor i prilagodba nadogradnje na implantatima

    OpenAIRE

    Belamarić, Sara

    2017-01-01

    Implantatne nadogradnje su spojni elementi između tijela implantata, kirurški postavljenog u kost, koji predstavlja zamjenu za prirodni korijen zuba i protetske suprastrukture kojom se nadoknađuje oblik, boja i funkcija zuba koji nedostaje. One predstavljaju središte funkcijskih i estetskih aspekata implantološke terapije. Imaju direktan utjecaj na dugoročnu prognozu i uspjeh ovog terapijskog postupka. Danas na tržištu postoji čitav niz dostupnih implantatnih nadogradnji. Najčešći materijali ...

  1. Recent results and prospects from NA62

    Directory of Open Access Journals (Sweden)

    Bizzeti Andrea

    2016-01-01

    K+ → π+ vv̄ is a theoretically very clean decay where indirect effects of new physics may be detectable. The NA62 apparatus has been significantly upgraded between 2008 and 2014 in order to measure the branching ratio of this decay with 10% precision. The NA62 experiment took data with the new setup in pilot runs in 2014 and 2015, reaching the design beam intensity. Results of first data quality studies in view of the 2016-2017 physics runs are presented.

  2. MEDGENERACIJSKI PRENOS ZNANJA NA DELOVNEM MESTU

    OpenAIRE

    Movern, Tina

    2015-01-01

    Prenos znanja med ljudmi igra ključno vlogo pri razvoju ter napredku človeštva. Nekaterih najbolj kompleksnih znanj kot so jeziki in kulturne norme, so lahko naučena oziroma priučena od drugih ljudi, ti pa so jih pridobili od prejšnjih generacij. Kot glavno gonilno silo razvoja neke organizacije bi prav lahko vzeli količino, kvaliteto in možnost upravljanja prenosa znanj v sami organizaciji, kar je tudi glavni predmet naše raziskave. Diplomska naloga je razdeljena na teoretični in empiri...

  3. Osteossarcoma parosteal: aspectos na radiologia convencional

    OpenAIRE

    Nanci Neto,Francisco; Marchiori,Edson; Vianna,Alberto Domingues; Aymoré,Ierecê Lins; Almeida,Ana Luiza Brito de; Irion,Klaus L.; Collares,Felipe Birchal

    2007-01-01

    OBJETIVO: Avaliar os achados clínicos mais importantes do osteossarcoma parosteal e descrever os seus aspectos mais comuns na radiologia convencional. MATERIAIS E MÉTODOS: Estudo retrospectivo com 26 pacientes com osteossarcoma parosteal, provenientes do arquivo do Clube do Osso, Rio de Janeiro, RJ, e análise dos principais achados clínicos e aspectos radiológicos. RESULTADOS: A doença predominou em pacientes do sexo feminino e teve idade média de acometimento na terceira década de vida. Os a...

  4. O problema do conhecimento verdadeiro na epidemiologia

    Directory of Open Access Journals (Sweden)

    Ayres José Ricardo de Carvalho Mesquita

    1992-01-01

    Full Text Available São examinadas as bases filosóficas da validação do conhecimento científico, com o intuito de estabelecer uma visão crítica a respeito da adoção das proposições de Popper na epidemiologia. Ressalta-se o caráter conservador que resulta das limitações técnicas implicadas na sua adoção, não obstante o evidente aumento da racionalidade e da criatividade heurística que propicia.

  5. Na+/K+-ATPase: Activity and inhibition

    Science.gov (United States)

    Čolović, M.; Krstić, D.; Krinulović, K.; Momić, T.; Savić, J.; Vujačić, A.; Vasić, V.

    2009-09-01

    The aim of the study was to give an overview of the mechanism of inhibition of Na+/K+-ATPase activity induced by some specific and non specific inhibitors. For this purpose, the effects of some ouabain like compounds (digoxin, gitoxin), noble metals complexes ([PtCl2DMSO2], [AuCl4]-, [PdCl4]2-, [PdCl(dien)]+, [PdCl(Me4dien)]+), transition metal ions (Cu2+, Zn2+, Fe2+, Co2+), and heavy metal ions (Hg2+, Pb2+, Cd2+) on the activity of Na+/K+-ATPase from rat synaptic plasma membranes (SPM), porcine cerebral cortex and human erythrocytes were discussed.

  6. Na, K-ATPase as signaling transducer

    OpenAIRE

    Li, Juan

    2007-01-01

    It is now generally agreed that Na,K-ATPase (NKA), in addition to its role in the maintenance of Na+ and K+ gradients across the cell membrane, is a signal transducer. Our group has identified a novel signaling pathway where NKA interact with IP3R to form a signaling microdomain. Ouabain, a specific ligand of NKA, activates this pathway, triggers slow Ca2+ oscillations and activates NF-κB. In current study, the molecular mechanisms and some important downstream effects of NK...

  7. Europlanet-2020 NA1 Exchange Program

    Science.gov (United States)

    Genzer, M.; Szego, K.; Haukka, H.; Harri, A.-M.

    2017-09-01

    The task of Exchange Program of NA1 is to support the activities of EPN2020 with experts and scientific exchange whenever it is needed. Short visits (up to 1 week) with the goal of improving infrastructure facilities and services offered to the scientific community are supported from this task. Since the start of the EPN2020 in September 2015 we have received and approved 14 applications for exchange program travel. More general and specifically targeted calls are planned for the future. The calls are announced on Europlanet-2020 NA1 web site.

  8. Abordagem neurologica na sindrome do X fragil

    OpenAIRE

    Marilisa Mantovani Guerreiro

    1993-01-01

    Resumo: Com o propósito de realizar a abordagem neurológica na Síndrome do X Frágil (SXF), estudaram-se 11 pacientes com este diagnóstico citogenético. A idade variou de 8 a 19 anos. Nove pacientes eram do sexo masculino e dois do feminino. Todos os indivíduos apresentaram pavilhões auriculares grandes e faces alongadas. Observou-se fronte proeminente em 63% dos casos e macrorquidia em 33% dentre aqueles do sexo masculino. Atraso na aquisição da fala, fala repetitiva, perseverativa, impulsiva...

  9. MANAGEMENT DOGODKOV NA PRIMERU NIKE KONVENCIJE

    OpenAIRE

    Kapić, Sara

    2010-01-01

    V diplomski nalogi je predstavljen potek ustvarjanja in izvedbe dogodka, ki zajema številne aktivnosti, in sicer na primeru Nike konvencije. Namen diplomske naloge je namreč podati kritično oceno izvajanja aktivnosti, z namenom ugotoviti, katere aktivnosti bi se v okviru upravljanja z dogodkom lahko izpeljale boljše in podati predloge za uspešnejšo zasnovo in organizacijo naslednje Nike konvencije. Na podlagi posnetka je ugotovljeno, da je pri organizaciji, vodenju, izvedbi in nadzoru prihaja...

  10. Alterações cognitivas na esquizofrenia

    OpenAIRE

    THEIL, Ruth Bonow

    2003-01-01

    Este estudo é uma revisão da literatura sobre o comprometimento cognitivo na esquizofrenia. Objetivou-se a análise da natureza e do padrão desse comprometimento, o estabelecimento de associações entre as variáveis clínicas e o desempenho neuropsicológico, e a determinação das correlações entre os déficits cognitivos na esquizofrenia e seus substratos neurais subjacentes. Foram inicialmente revistos os conceitos de esquizofrenia e sua evolução histórica, aspectos clínicos, cl...

  11. IDENTIDADE E CORPO NA MARCHA DAS VADIAS

    OpenAIRE

    Ribeiro Quintanilha de Souza, Aline

    2015-01-01

    O objetivo deste trabalho é analisar os temas de identidade de gênero e corporalidade na Marcha das Vadias. Esta é um movimento social que tem recebido visibilidade e experimentado um grande crescimento em adeptos e importância para as questões de gênero no Brasil. Este trabalho busca entender como práticas corporais são construídas para um objetivo político específico. Pretendo relacionar as principais reivindicações políticas desenvolvidas na manifestação com a construção da identidade "vad...

  12. Glutathionylation-Dependence of Na(+)-K(+)-Pump Currents Can Mimic Reduced Subsarcolemmal Na(+) Diffusion.

    Science.gov (United States)

    Garcia, Alvaro; Liu, Chia-Chi; Cornelius, Flemming; Clarke, Ronald J; Rasmussen, Helge H

    2016-03-08

    The existence of a subsarcolemmal space with restricted diffusion for Na(+) in cardiac myocytes has been inferred from a transient peak electrogenic Na(+)-K(+) pump current beyond steady state on reexposure of myocytes to K(+) after a period of exposure to K(+)-free extracellular solution. The transient peak current is attributed to enhanced electrogenic pumping of Na(+) that accumulated in the diffusion-restricted space during pump inhibition in K(+)-free extracellular solution. However, there are no known physical barriers that account for such restricted Na(+) diffusion, and we examined if changes of activity of the Na(+)-K(+) pump itself cause the transient peak current. Reexposure to K(+) reproduced a transient current beyond steady state in voltage-clamped ventricular myocytes as reported by others. Persistence of it when the Na(+) concentration in patch pipette solutions perfusing the intracellular compartment was high and elimination of it with K(+)-free pipette solution could not be reconciled with restricted subsarcolemmal Na(+) diffusion. The pattern of the transient current early after pump activation was dependent on transmembrane Na(+)- and K(+) concentration gradients suggesting the currents were related to the conformational poise imposed on the pump. We examined if the currents might be accounted for by changes in glutathionylation of the β1 Na(+)-K(+) pump subunit, a reversible oxidative modification that inhibits the pump. Susceptibility of the β1 subunit to glutathionylation depends on the conformational poise of the Na(+)-K(+) pump, and glutathionylation with the pump stabilized in conformations equivalent to those expected to be imposed on voltage-clamped myocytes supported this hypothesis. So did elimination of the transient K(+)-induced peak Na(+)-K(+) pump current when we included glutaredoxin 1 in patch pipette solutions to reverse glutathionylation. We conclude that transient K(+)-induced peak Na(+)-K(+) pump current reflects the effect

  13. In vivo PTH provokes apical NHE3 and NaPi2 redistribution and Na-K-ATPase inhibition

    DEFF Research Database (Denmark)

    Zhang, Y; Norian, J M; Magyar, C E

    1999-01-01

    The aim of this study was to test the hypothesis that in vivo administration of parathyroid hormone (PTH) provokes diuresis/natriuresis through redistribution of proximal tubule apical sodium cotransporters (NHE3 and NaPi2) to internal stores and inhibition of basolateral Na-K-ATPase activity....../diuresis and NHE3 and NaPi2 internalization, and that Na-K-ATPase inhibition is not secondary to depressed apical Na+ transport....

  14. Water transport by the renal Na(+)-dicarboxylate cotransporter

    DEFF Research Database (Denmark)

    Meinild, A K; Loo, D D; Pajor, A M

    2000-01-01

    This study investigated the ability of the renal Na(+)-dicarboxylate cotransporter, NaDC-1, to transport water. Rabbit NaDC-1 was expressed in Xenopus laevis oocytes, cotransporter activity was measured as the inward current generated by substrate (citrate or succinate), and water transport...... was monitored by the changes in oocyte volume. In the absence of substrates, oocytes expressing NaDC-1 showed an increase in osmotic water permeability, which was directly correlated with the expression level of NaDC-1. When NaDC-1 was transporting substrates, there was a concomitant increase in oocyte volume....... This solute-coupled influx of water took place in the absence of, and even against, osmotic gradients. There was a strict stoichiometric relationship between Na(+), substrate, and water transport of 3 Na(+), 1 dicarboxylate, and 176 water molecules/transport cycle. These results indicate that the renal Na...

  15. Intracellular Na(+) and metabolic modulation of Na/K pump and excitability in the rat suprachiasmatic nucleus neurons.

    Science.gov (United States)

    Wang, Yi-Chi; Yang, Jyh-Jeen; Huang, Rong-Chi

    2012-10-01

    Na/K pump activity and metabolic rate are both higher during the day in the suprachiasmatic nucleus (SCN) that houses the circadian clock. Here we investigated the role of intracellular Na(+) and energy metabolism in regulating Na/K pump activity and neuronal excitability. Removal of extracellular K(+) to block the Na/K pump excited SCN neurons to fire at higher rates and return to normal K(+) to reactivate the pump produced rebound hyperpolarization to inhibit firing. In the presence of tetrodotoxin to block the action potentials, both zero K(+)-induced depolarization and rebound hyperpolarization were blocked by the cardiac glycoside strophanthidin. Ratiometric Na(+) imaging with a Na(+)-sensitive fluorescent dye indicated saturating accumulation of intracellular Na(+) in response to pump blockade with zero K(+). The Na(+) ionophore monensin also induced Na(+) loading and hyperpolarized the membrane potential, with the hyperpolarizing effect of monensin abolished in zero Na(+) or by pump blockade. Conversely, Na(+) depletion with Na(+)-free pipette solution depolarized membrane potential but retained residual Na/K pump activity. Cyanide inhibition of oxidative phosphorylation blocked the Na/K pump to depolarize resting potential and increase spontaneous firing in most cells, and to raise intracellular Na(+) levels in all cells. Nonetheless, the Na/K pump was incompletely blocked by cyanide but completely blocked by iodoacetate to inhibit glycolysis, indicating the involvement of both oxidative phosphorylation and glycolysis in fueling the Na/K pump. Together, the results indicate the importance of intracellular Na(+) and energy metabolism in regulating Na/K pump activity as well as neuronal excitability in the SCN neurons.

  16. Presoja notranjih kontrol pri obračunu davka na dodano vrednost na primeru "Podjetja x"

    OpenAIRE

    Majcen, Borut

    2016-01-01

    Poslovanje podjetja si je ob odsotnosti notranjih kontrol nemogoče predstavljati. Podjetja so podvržena raznim tveganjem, še posebej v današnjih razmerah globalnega poslovanja, ko se podjetja soočajo z vedno novimi izzivi, kar prinaša tudi nova tveganja. Najučinkovitejši ukrep za obvladovanje tveganj predstavlja vzpostavitev sistema notranjih kontrol. Obvladovanje tveganj pa ne poteka samo na ravni podjetja kot celote, ampak je prisotno na vseh področjih delovanja podjetja, torej tudi na p...

  17. (1) Na-Allah et al

    African Journals Online (AJOL)

    Adeyinka Odunsi

    Na-Allah, Y., Zamnao, A. *Garba, S. and Abdullahi, A. U.. Department of Animal Science, Faculty of Agriculture,. Usmanu Danfodiyo University, P. M. B. 2346, Sokoto-Nigeria. *Corresponding author: email; sanigarba2003@yahoo.com Phone no. +234(0)8067090255. Abstract. This study evaluated the pre-‐weaning growth ...

  18. Habitus professoral na sala de aula virtual

    Directory of Open Access Journals (Sweden)

    Alexandre Marinho Pimenta

    2014-09-01

    Full Text Available Entendendo que a indiferença na ação pedagógica contribui para a reprodução das desigualdades no sistema de ensino, o presente artigo busca captar, a partir de entrevistas semiestruturadas, traços do habitus de professores supervisores de disciplinas do curso de Licenciatura em Pedagogia na modalidade a distância na Universidade de Brasília - UnB no âmbito do Sistema Universidade Aberta do Brasil - UAB. As orientações metodológicas de Bourdieu (2007 foram um dos elementos orientadores na análise das entrevistas, considerando ainda o uso heurístico do conceito de habitus. Conclui-se que o habitus professoral envolve esforços voluntários em busca de uma ação pedagógica diferenciada. No entanto, ele é ambíguo e condescendente frente aos limites do modelo de EaD no âmbito da UAB. Ao fim, os dados analisados permitem fornecer elementos para reorientação político-pedagógica que vise a um novo modelo de EaD nacional.

  19. Le Hodler d'Iéna

    OpenAIRE

    2017-01-01

    Suites de la protestation contre le bombardement de la cathédrale de Reims. Nouvelle proposition de M. Gunsburger pour le rachat du tableau de Hodler "Départ des étudiants d'Iéna pour la guerre de libération contre Napoléon en 1813".

  20. Study of deconfinement in NA50

    Indian Academy of Sciences (India)

    Corrado Cicalo

    from the forward hadronic energy measured in the very forward hadronic calorimeter. 2. Experimental setup and data selection. The NA50 apparatus [6] mainly consists of a muon spectrometer, a segmented active target and three independent centrality detectors: an electromagnetic calorimeter which measures the neutral ...

  1. Pijn tijdens of na de wortelkanaalbehandeling

    NARCIS (Netherlands)

    Wesselink, P.R.

    2012-01-01

    Een wortelkanaalbehandeling kan pijn veroorzaken tijdens en/of na de behandeling. Tijdens de behandeling moet dan onderscheid worden gemaakt tussen pijn bij een pulpitis en pijn bij een necrotische pulpa. In beide gevallen kan die pijn effectief worden bestreden, afhankelijk van de toestand waarin

  2. Leitura na escola: um barco à deriva?

    Directory of Open Access Journals (Sweden)

    Teixeira, Marlene

    2008-01-01

    Full Text Available Este artigo busca, na teoria da enunciação de É. Benveniste, elementos para repensar o trabalho com a leitura na escola. Considera que, na discussão das noções gêmeas de forma e sentido, o autor formula uma concepção de significado que, de um lado, pode deter a interpretação à deriva, implicada na visão de leitura centrada no leitor, e, de outro lado, possibilita que se transcenda a idéia de que é pela decifração mdo código que se dá o processo de construção do significado. Conclui que, no processo de leitura, é sempre de um trabalho com a língua que se trata, trabalho que se renova a cada ato de aproximação do aluno com o texto, porque a língua é submetida ao ato de enunciação

  3. NA49: lead-lead collision

    CERN Multimedia

    1996-01-01

    This is an image of an actual lead ion collision taken from tracking detectors on the NA49 experiment, part of the heavy ion project at CERN. These collisions produce a very complicated array of hadrons as the heavy ions break up. It is hoped that one of these collisions will eventually create a new state of matter known as quark-gluon plasma.

  4. Nucleotide binding to Na+/K+-ATPase

    Czech Academy of Sciences Publication Activity Database

    Kubala, Martin; Lánský, Zdeněk; Ettrich, R.; Plášek, J.; Teisinger, Jan; Amler, Evžen

    2005-01-01

    Roč. 272, č. S1 (2005), s. 191-191 E-ISSN 1742-4658. [FEBS Congress /30./ and IUBMB Conference /9./. 02.07.2005-07.07.2005, Budapest] Keywords : Na+/K+- ATPase * ATP binding * TNP-ATP Subject RIV: BO - Biophysics

  5. Therapy of hyperthyroidism with Na131I

    International Nuclear Information System (INIS)

    Kakehi, Hirotake; Furukawa, Takashi; Fukakusa, Shunichi; Futonaka, Hiroshi; Takahashi, Yuji

    1984-01-01

    Forty one patients of hyperthyroidism were treated with Na 131 I. Men and women are in the ratio 1:3.1. The ages of patients are between twenties and sixties and the forties are the highest in number. The observation period of clinical courses is between 1 and 8 years. The number of patients observed over 5 years are 51% of them and over 2 years are 83%. The treatment frequency is as follows: On 37 cases each one was treated once with Na 131 I. 2 cases twice, 1 case at 4 times in 3 years and 1 case at 5 times in 6 years. The treatment doses are between 4,000-6,000 rad (40-60 Gray). In the cases treated with the irradiation dose of 6,000 rad, we often saw hypothyroidism. In cases aiming 4,000-5,000 rad, there is a tendency of leaving hyperthyroidism unrecovered. In conclusion, the patients should be treated giving 4,000-5,000 rad or with Na 131 I doses of 3-6mCi. If the effects of the treatment are insufficient, the patients should be further treated with anti-thyroid drug or treated again with Na 131 I. As the result, there are at present 25 cases (61.0%) in normal status of the thyroid gland, 12 cases (29.2%) in hyperthyroidism and 4 cases (9.8%) in hypothyroidism totaling 41 cases in all. (author)

  6. NA48: Wiring up for Change

    CERN Multimedia

    2001-01-01

    The NA48 Collaboration is rebuilding its drift chambers ready for the experiment to start up again this coming July. An intricate task involving the soldering of over 24,000 wires! The future of the NA48 experiment is coming right down to the wire, that is, the wires which the Collaboration is installing in the clean room of Hall 887 on the Prévessin site. Six days a week, technicians are working in shifts to rebuild the experiment's drift chambers. The original chambers were damaged when a section of a vacuum tube imploded at the end of 1999. A year ago, CERN gave the green light for this essential part of the spectrometer to be rebuilt, so the NA48 experiment, which studies CP violation (see box), still has a bright future ahead of it. Three years of data-taking ahead The NA48 experiment aims to penetrate the secrets of CP (Charge Parity) violation. Charge and parity are two parameters which distinguish a particle from an antiparticle. In other words, an electron possesses a negative electric ...

  7. Study of deconfinement in NA50

    Indian Academy of Sciences (India)

    Corrado Cicalo

    The anomalous J/ψ pattern suppression observed in NA50 experiment is a clear evidence of the transition to a deconfined state of matter. Acknowledgements. This work was partially supported by Fundaç˜ao para a Ciência e a Tecnologia, by INTAS grant 96-0231 and by the Russian Foundation for Fundamental Research, ...

  8. Development of sulfide solid electrolytes and interface formation processes for bulk-type all-solid-state Li and Na batteries

    Directory of Open Access Journals (Sweden)

    Akitoshi Hayashi

    2016-07-01

    Full Text Available All-solid-state batteries with inorganic solid electrolytes are recognized as an ultimate goal of rechargeable batteries because of their high safety, versatile geometry and good cycle life. Compared to thin-film batteries, increasing the reversible capacity of bulk-type all-solid-state batteries using electrode active material particles is difficult because contact areas at solid–solid interfaces between the electrode and electrolyte particles are limited. Sulfide solid electrolytes have several advantages of high conductivity, wide electrochemical window, and appropriate mechanical properties such as formability, processability, and elastic modulus. Sulfide electrolyte with Li7P3S11 crystal has the highest Li+ ion conductivity of 1.7 × 10-2 S cm-1 at 25 °C. It is far beyond the Li+ ion conductivity of conventional organic liquid electrolytes. The Na+ ion conductivity of 7.4 × 10-4 S cm-1 is achieved for Na3.06P0.94Si0.06S4 with cubic structure. Moreover, formation of favorable solid–solid interfaces between electrode and electrolyte is important for realizing solid-state batteries. Sulfide electrolytes have better formability than oxide electrolytes. Consequently, a dense electrolyte separator and closely attached interfaces with active material particles are achieved via room-temperature sintering of sulfides merely by cold pressing without heat treatment. Elastic moduli for sulfide electrolytes are smaller than that of oxide electrolytes, and Na2S-P2S5 glass electrolytes have smaller Young’s modulus than Li2S-P2S5 electrolytes. Cross-sectional SEM observations for a positive electrode layer reveal that sulfide electrolyte coating on active material particles increases interface areas even with a minimum volume of electrolyte, indicating that the energy density of bulk-type solid-state batteries is enhanced. Both surface coating of electrode particles and preparation of nanocomposite are effective for increasing the reversible

  9. Zasvojenost z igrami na srečo : magistrsko delo

    OpenAIRE

    Rozman, Patricia

    2014-01-01

    Namen magistrske naloge je predstaviti eno izmed najbolj skritih oblik zasvojenosti, to je zasvojenost z igrami na srečo. Zanimalo me je, kako ta oblika zasvojenosti vpliva na posameznika, tako telesno kot duševno. Ali posameznikova zasvojenost vpliva na ljudi okoli njega, na njegovo družino, prijatelje, znance in službo, ter kako se zasvojenec s tem sooča. Predvsem me je zanimalo, ali zasvojenost z igrami na srečo vodi v kriminalna dejanja in kakšna so ta dejanja ter kako je to ureje...

  10. VPLIV BARVE EMBALAŽE NA ZAZNAVANJE OKUSA GOSTEGA SOKA

    OpenAIRE

    Prevolšek, Daša

    2016-01-01

    Z barvami se srečujemo na vsakem koraku. Mogoče se njihovega vpliva ne zavedamo povsem, vendar nam lahko že pogled na določeno barvo dvigne ali pokvari razpoloženje. Barve imajo zelo velik vpliv na človeka in v nas prebujajo različna čustva. Nekatere barve so pozitivne in nas osrečujejo, druge pa na nas delujejo negativno. Ravno zaradi tega je tudi za oblikovalce embalaže zelo pomembno, da vnaprej predvidijo, kako se bodo potencialni porabniki njihovega izdelka odzivali na njihovo embalažo. P...

  11. IZOBRAŽEVANJE NA DOMU - ŠTUDIJA PRIMERA

    OpenAIRE

    Križan, Urška

    2014-01-01

    V teoretičnem delu se skozi literaturo seznanjamo z zakoni, ki na območju Republike Slovenije urejajo izobraževanje na domu, pa tudi s smernicami, ki veljajo na področju organiziranosti takega pouka. Po enem tednu, ki smo ga preživeli na domačiji skupaj s tremi šoloobveznimi otroki, ki se šolajo na domu, ugotavljamo, da je izvajanje izobraževanja na domu zmeraj v skladu z zakoni in pogosto v skladu s smernicami.

  12. Effects of non-uniform root zone salinity on water use, Na+ recirculation, and Na+ and H+ flux in cotton.

    Science.gov (United States)

    Kong, Xiangqiang; Luo, Zhen; Dong, Hezhong; Eneji, A Egrinya; Li, Weijiang

    2012-03-01

    A new split-root system was established through grafting to study cotton response to non-uniform salinity. Each root half was treated with either uniform (100/100 mM) or non-uniform NaCl concentrations (0/200 and 50/150 mM). In contrast to uniform control, non-uniform salinity treatment improved plant growth and water use, with more water absorbed from the non- and low salinity side. Non-uniform treatments decreased Na(+) concentrations in leaves. The [Na(+)] in the '0' side roots of the 0/200 treatment was significantly higher than that in either side of the 0/0 control, but greatly decreased when the '0' side phloem was girdled, suggesting that the increased [Na(+)] in the '0' side roots was possibly due to transportation of foliar Na(+) to roots through phloem. Plants under non-uniform salinity extruded more Na(+) from the root than those under uniform salinity. Root Na(+) efflux in the low salinity side was greatly enhanced by the higher salinity side. NaCl-induced Na(+) efflux and H(+) influx were inhibited by amiloride and sodium orthovanadate, suggesting that root Na(+) extrusion was probably due to active Na(+)/H(+) antiport across the plasma membrane. Improved plant growth under non-uniform salinity was thus attributed to increased water use, reduced leaf Na(+) concentration, transport of excessive foliar Na(+) to the low salinity side, and enhanced Na(+) efflux from the low salinity root.

  13. Synthesis of Na-A and/or Na-X zeolite/porous carbon composites from carbonized rice husk

    Science.gov (United States)

    Katsuki, Hiroaki; Komarneni, Sridhar

    2009-07-01

    Na-A and/or Na-X zeolite/porous carbon composites were prepared under hydrothermal conditions by NaOH dissolution of silica first from carbonized rice husk followed by addition of NaAlO 2 and in situ crystallization of zeolites i.e., using a two-step process. When a one-step process was used, both Na-A and Na-X zeolites crystallized on the surface of carbon. Na-A or Na-X zeolite crystals were prepared on the porous carbonized rice husk at 90 °C for 2-6 h by changing the SiO 2/Al 2O 3, H 2O/Na 2O and Na 2O/SiO 2 molar ratios of precursors in the two-step process. The surface area and NH 4+-cation exchange capacity (CEC) of Na-A zeolite/porous carbon were found to be 171 m 2/g and 506 meq/100 g, respectively, while those of Na-X zeolite/porous carbon composites were 676 m 2/g and 317 meq/100 g, respectively. Na-A and Na-X zeolites are well-known microporous and hydrophilic materials while carbonized rice husk was found to be mesoporous (pores of ˜3.9 nm) and hydrophobic. These hybrid microporous-mesoporous and hydrophilic-hydrophobic composites are expected to be useful for decontamination of metal cations as well as organic contaminants simultaneously.

  14. Homology of the open moduli space of curves

    DEFF Research Database (Denmark)

    Madsen, Ib Henning

    2012-01-01

    This is a survey on the proof of a generalized version of the Mumford conjecture obtained in joint work with M. Weiss stating that a certain map between some classifying spaces which a priori have different natures induces an isomorphism at the level of integral homology. We also discuss our proo...

  15. Intermediate Jacobians and Hodge structures of moduli spaces

    Indian Academy of Sciences (India)

    space of vector bundles on a curve is studied. Analysis of the third cohomology yields a new proof of a Torelli theorem. Keywords. Vector bundle; mixed Hodge structure; intermediate Jacobian. 1. Introduction. We work throughout over the complex numbers C, i.e. all schemes are over C and all maps of schemes are maps of ...

  16. Large BCFT moduli in open string field theory

    Czech Academy of Sciences Publication Activity Database

    Maccaferri, C.; Schnabl, Martin

    2015-01-01

    Roč. 2015, č. 8 (2015), s. 149 ISSN 1029-8479 R&D Projects: GA ČR(CZ) GA14-31689S Institutional support: RVO:68378271 Keywords : String Field Theory * tachyon condensation * D-branes Subject RIV: BE - Theoretical Physics Impact factor: 6.023, year: 2015

  17. Minimum Moduli in Von Neumann Algebras | Gopalraj | Quaestiones ...

    African Journals Online (AJOL)

    In this paper we answer a question raised in [12] in the affirmative, namely that the essential minimum modulus of an element in a von. Neumann algebra, relative to any norm closed two-sided ideal, is equal to the minimum modulus of the element perturbed by an element from the ideal. As a corollary of this result, we ...

  18. Structure of digraphs associated with quadratic congruences with composite moduli

    Czech Academy of Sciences Publication Activity Database

    Somer, L.; Křížek, Michal

    2006-01-01

    Roč. 306, č. 18 (2006), s. 2174-2185 ISSN 0012-365X R&D Projects: GA MŠk(CZ) 1P05ME749 Institutional research plan: CEZ:AV0Z10190503 Keywords : Fermat numbers * Mersenne numbers * Carmichael function Subject RIV: BA - General Mathematics Impact factor: 0.347, year: 2006

  19. Moduli for decorated tuples of sheaves and representation spaces ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    of these vortex equations have an interpretation as pairs (P,τ) as above, satisfying cer- tain stability conditions which ...... the identification of C. P(Ev)(l) with H0(Ev(l)). 2. 3.4 ρ-pairs. In this section, we will fix a dimension vector r = (rv,v ∈ V ) and a homogeneous representation ρ : GL(V,r) −→ GL(A). By slightly deviating from ...

  20. Flexural strength and moduli of hypoallergenic denture base materials.

    Science.gov (United States)

    Pfeiffer, Peter; Rolleke, Christian; Sherif, Lamia

    2005-04-01

    Hypoallergenic denture base materials show no residual methyl methacrylate (MMA) or significantly lower residual MMA monomer content compared to polymethyl methacrylate-based (PMMA) heat-polymerizing acrylic resin. There is insufficient knowledge of the mechanical properties of hypoallergenic denture base materials to warrant their use in place of PMMA-based acrylic resins for patients with allergic reaction to MMA. This in vitro study compared flexural strength and flexural modulus of 4 hypoallergenic denture base materials with flexural strength/modulus of a PMMA heat-polymerizing acrylic resin. The following denture base resins were examined: Sinomer (heat-polymerized, modified methacrylate), Polyan (thermoplastic, modified methacrylate), Promysan (thermoplastic, enterephthalate-based), Microbase (microwave-polymerized, polyurethane-based), and Paladon 65 (heat-polymerized, methacrylate, control group). Specimens of each material were tested for flexural strength and flexural modulus (MPa, n = 5) according to ISO 1567:1999. The data were analyzed with 1-way analysis of variance and the Bonferroni-Dunn multiple comparisons post hoc analysis for each test variable (alpha=.05). Flexural strength of Microbase (67.2 +/- 5.3 MPa) was significantly lower than Paladon 65 (78.6 +/- 5.5 MPa, P denture base materials fulfilled the requirements regarding flexural strength (>65 MPa). With the exception of Sinomer, the tested denture base resins passed the requirements of ISO 1567 regarding flexural modulus (>2000 MPa). Flexural modulus of Promysan was significantly higher than the PMMA material. Microbase and Sinomer exhibited significantly lower flexural strength and flexural modulus, respectively, than PMMA. The other groups did not differ significantly from the control group.

  1. Yang-Mills moduli space in the adiabatic limit

    Science.gov (United States)

    Lechtenfeld, Olaf; Popov, Alexander D.

    2015-10-01

    We consider the Yang-Mills equations for a matrix gauge group G inside the future light cone of four-dimensional Minkowski space, which can be viewed as a Lorentzian cone C({H}3) over the three-dimensional hyperbolic space H3. Using the conformal equivalence of C({H}3) and the cylinder {{R}}× {H}3, we show that, in the adiabatic limit when the metric on H3 is scaled down, classical Yang-Mills dynamics is described by geodesic motion in the infinite-dimensional group manifold {C}∞ ({S}∞ 2,G) of smooth maps from the boundary two-sphere {S}∞ 2=\\partial {H}3 into the gauge group G.

  2. First Order Description of Black Holes in Moduli Space

    CERN Document Server

    Andrianopoli, Laura; Orazi, Emanuele; Trigiante, Mario

    2007-01-01

    We show that the second order field equations characterizing extremal solutions for spherically symmetric, stationary black holes are in fact implied by a system of first order equations given in terms of a prepotential W. This confirms and generalizes the results in hep-th/0702088. When the black holes are solutions of extended supergravities we are able to find an explicit expression for the prepotentials which reproduce all the attractors of the four dimensional N>2 theories. We discuss a possible extension of our considerations to the non extremal case.

  3. An Introduction to Riemann Surfaces, Algebraic Curves and Moduli Spaces

    CERN Document Server

    Schlichenmaier, Martin

    2007-01-01

    This book gives an introduction to modern geometry. Starting from an elementary level the author develops deep geometrical concepts, playing an important role nowadays in contemporary theoretical physics. He presents various techniques and viewpoints, thereby showing the relations between the alternative approaches. At the end of each chapter suggestions for further reading are given to allow the reader to study the touched topics in greater detail. This second edition of the book contains two additional more advanced geometric techniques: (1) The modern language and modern view of Algebraic Geometry and (2) Mirror Symmetry. The book grew out of lecture courses. The presentation style is therefore similar to a lecture. Graduate students of theoretical and mathematical physics will appreciate this book as textbook. Students of mathematics who are looking for a short introduction to the various aspects of modern geometry and their interplay will also find it useful. Researchers will esteem the book as reliable ...

  4. Page 1 Moduli for bundles over curves - 325 through the ...

    Indian Academy of Sciences (India)

    through the openimmersion (LX &,)(C) s (L x é,)(C). Therefore L x , has a reduction to P and hence seSer. 3.23. Lemma. Let : – S x X be a family of semistable G-bundles. Suppose there exist. (i) a dense open subset T of S. (ii) a reductive subgroup Mo of G of maximal rank and. (iii) a stable Mo-bundle Eo with the following ...

  5. Moduli for decorated tuples of sheaves and representation spaces ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    manifolds, one associates to the data of G, ρ, and a fixed differentiable principal G-bundle P cer- tain vortex equations. By the so-called Kobayashi–Hitchin correspondence, the solutions of these vortex equations have an interpretation as pairs (P,τ) ...

  6. Moduli space of Parabolic vector bundles over hyperelliptic curves

    Indian Academy of Sciences (India)

    27

    smooth irreducible projective curve Y such that the quotient X := Y/Γ is also smooth and irreducible with natural projection p : Y −→ X, then there is an equivalence of categories between the category of ..... It is obvious that the first projection Gen(Φ) −→ P1 has as fiber over µ, the variety of g planes isotropic to qλ, which has ...

  7. Evaluation of Procedures for Backcalculation of Airfield Pavement Moduli

    Science.gov (United States)

    2015-08-01

    surface and the base pavement is positively in good condition Cb = 0.8 if only reflective cracks or only joint reflective cracks are present on...backcalculation routine with the real pavement scenario.  Testing in proximity of cracks or joints results in measured deflection basins that... pavement (JPCP) 1 Plant mix (emulsified asphalt) material, cold-laid 20 Jointed reinforced concrete pavement (JRCP) 1 Cracked and seated PCC

  8. Adiabatic concept of Young´s moduli in metals

    Czech Academy of Sciences Publication Activity Database

    Pekárek, Viktor

    2006-01-01

    Roč. 51, č. 1 (2006), s. 45-53 ISSN 0001-7043 Institutional research plan: CEZ:AV0Z20570509 Keywords : temperature changes and heat dilatations under elastic strain * attenuation of elastic responses * thermo-mechanical anomaly Subject RIV: BM - Solid Matter Physics ; Magnetism

  9. Intermediate Jacobians and Hodge structures of moduli spaces

    Indian Academy of Sciences (India)

    For third cohomology, a more refined analysis yields: Theorem 1.0.2. Let X be a curve of genus g ! ...... deformation theoretic techniques in x 4), the method for obtaining the first estimate is as follows. Let V 33 yZ be a parabolic ..... The homotopy exact sequence tells us that UH is simply connected. Proposition 6.3.1 applied ...

  10. Modular forms and the cohomology of moduli spaces

    NARCIS (Netherlands)

    Faber, C.F.

    2012-01-01

    In the conference, I talked about the ongoing joint work with Jonas Bergstr om and Gerard van der Geer. See [5], xx2{3 for a survey and [1] for a detailed presentation. Some of the results mentioned in the talk and below have not yet been written up.

  11. Theoretical Relationships Between Moduli for Soil Layers Beneath Concrete Pavements.

    Science.gov (United States)

    method of analysis used for rigid pavements and the elastic layer method of analysis used for both rigid and flexible pavements. Twenty-three pavement sections were selected to illustrate the usage of these relationships. These sections represent the widest possible variation of rigid pavement types for which sufficient materials data was available. For the sections studied and within the context of linear analysis, these relationships demonstrate that the peak pavement stress can usually be computed by either method

  12. Moduli and Characteristics of Monotonicity in Some Banach Lattices

    Czech Academy of Sciences Publication Activity Database

    Foralewski, P.; Hudzik, H.; Kaczmarek, R.; Krbec, Miroslav

    -, - (2010), s. 852346 ISSN 1687-1812 R&D Projects: GA AV ČR IAA100190804; GA MŠk LC06052 Institutional research plan: CEZ:AV0Z10190503 Keywords : Banach lattice * characteristics of monotonicity * Orlicz function space * Orlicz sequence space Subject RIV: BA - General Mathematics http://www.fixedpointtheoryandapplications.com/content/2010/1/852346

  13. Moduli and Characteristics of Monotonicity in Some Banach Lattices

    Directory of Open Access Journals (Sweden)

    Miroslav Krbec

    2010-01-01

    Full Text Available First the characteristic of monotonicity of any Banach lattice X is expressed in terms of the left limit of the modulus of monotonicity of X at the point 1. It is also shown that for Köthe spaces the classical characteristic of monotonicity is the same as the characteristic of monotonicity corresponding to another modulus of monotonicity δ^m,E. The characteristic of monotonicity of Orlicz function spaces and Orlicz sequence spaces equipped with the Luxemburg norm are calculated. In the first case the characteristic is expressed in terms of the generating Orlicz function only, but in the sequence case the formula is not so direct. Three examples show why in the sequence case so direct formula is rather impossible. Some other auxiliary and complemented results are also presented. By the results of Betiuk-Pilarska and Prus (2008 which establish that Banach lattices X with ε0,m(X<1 and weak orthogonality property have the weak fixed point property, our results are related to the fixed point theory (Kirk and Sims (2001.

  14. Elastic moduli and elastic anisotropy of cold sprayed metallic coatings

    Czech Academy of Sciences Publication Activity Database

    Seiner, Hanuš; Cizek, J.; Sedlák, Petr; Huang, R.; Cupera, J.; Dlouhý, I.; Landa, Michal

    2016-01-01

    Roč. 291, April (2016), s. 342-347 ISSN 0257-8972 R&D Projects: GA ČR GA13-13616S; GA ČR(CZ) GA13-35890S Grant - others:NETME Centre Plus - národní program udržitelnosti(CZ) LO1202 Institutional support: RVO:61388998 Keywords : kinetic spray * CGDS * elastic properties * metals and alloys * deposition * resonant ultrasound spectroscopy Subject RIV: JG - Metallurgy Impact factor: 2.589, year: 2016 http://ac.els-cdn.com/S0257897216301165/1-s2.0-S0257897216301165-main.pdf?_tid=1083617a-017f-11e6-92e7-00000aacb361&acdnat=1460555773_2e80d3df20843f3af649bf3ac71c8844

  15. Atomistic Calculation of Elastic Moduli in Strained Silicon

    National Research Council Canada - National Science Library

    Zhu, Richard; Pan, Ernian; Chung, Peter W; Cai, Xinli; Liew, Kim M; Buldum, Alper

    2007-01-01

    .... Using our approach, the bulk modulus, effective elastic stiffnesses C11, C12, and C44 of the strained silicon, including also the effective Young's modulus and Poisson's ratio, are all calculated...

  16. Lattice Energies and Bulk Moduli of Ionic Crystals | Abdulsalam ...

    African Journals Online (AJOL)

    The Born-Lande equation has been used to calculate the lattice energy and bulk modulus of twenty one ionic crystals. These computations were carried out by means of a FORTRAN code, whose basic inputs are the name of crystal, the Born exponent, the number of charges and the lattice constant The lattice energies ...

  17. BCFT and OSFT moduli. An exact perturbative comparison

    Energy Technology Data Exchange (ETDEWEB)

    Larocca, Pier Vittorio; Maccaferri, Carlo [Universita di Torino, Dipartimento di Fisica, Torino (Italy); INFN, Sezione di Torino (Italy)

    2017-11-15

    Starting from the pseudo-B{sub 0} gauge solution for marginal deformations in OSFT, we analytically compute the relation between the perturbative deformation parameter λ in the solution and the BCFT marginal parameter λ, up to fifth order, by evaluating the Ellwood invariants. We observe that the microscopic reason why λ and λ are different is that the OSFT propagator renormalizes contact-term divergences differently from the contour deformation used in BCFT. (orig.)

  18. Equivalent moduli of continuity, Bloch's theorem for pluriharmonic ...

    Indian Academy of Sciences (India)

    Department of Mathematics, Hunan Normal University, Changsha, Hunan 410081, People's Republic of China; Department of Mathematics and Computational Science, Hengyang Normal University, Hengyang, Hunan 421008, People's Republic of China; Department of Mathematics, Indian Institute of Technology Madras, ...

  19. Brauer groups and obstruction problems moduli spaces and arithmetic

    CERN Document Server

    Hassett, Brendan; Várilly-Alvarado, Anthony; Viray, Bianca

    2017-01-01

    The contributions in this book explore various contexts in which the derived category of coherent sheaves on a variety determines some of its arithmetic. This setting provides new geometric tools for interpreting elements of the Brauer group. With a view towards future arithmetic applications, the book extends a number of powerful tools for analyzing rational points on elliptic curves, e.g., isogenies among curves, torsion points, modular curves, and the resulting descent techniques, as well as higher-dimensional varieties like K3 surfaces. Inspired by the rapid recent advances in our understanding of K3 surfaces, the book is intended to foster cross-pollination between the fields of complex algebraic geometry and number theory. Contributors: · Nicolas Addington · Benjamin Antieau · Kenneth Ascher · Asher Auel · Fedor Bogomolov · Jean-Louis Colliot-Thélène · Krishna Dasaratha · Brendan Hassett · Colin Ingalls · Martí Lahoz · Emanuele Macrì · Kelly McKinnie · Andrew Obus · Ekin Ozman · Raman...

  20. Cosserat moduli of anisotropic cancellous bone : A micromechanical analysis

    NARCIS (Netherlands)

    Fatemi, J.; Onck, P.R.; Poort, G.; Van Keulen, F.

    A micromechanical-based approach is proposed to quantify the effective (in the macroscopic sense) elastic constants of Cosserat materials. The material under investigation (cancellous bone) is cellular and classically elastic at the microscopic level and assumed to be dense Cosserat elastic at the

  1. Moduli induced cogenesis of baryon asymmetry and dark matter

    Directory of Open Access Journals (Sweden)

    Mansi Dhuria

    2016-05-01

    Full Text Available We study a cogenesis mechanism in which the observed baryon asymmetry of the universe and the dark matter abundance can be produced simultaneously at low reheating temperature without violating baryon number in the fundamental interactions. In particular, we consider a model which can be realized in the context of type IIB large volume string compactifications. The matter superfields in this model include additional pairs of color triplet and singlet superfields in addition to the Minimal Supersymmetric Standard Model (MSSM superfields. Assuming that the mass of the additional singlet fermions is O(GeV and of the color triplet fermions is O(TeV, we show that the modulus dominantly decays into the additional color triplet superfields. After soft supersymmetry (SUSY breaking, the lightest eigenstate of scalar component of color triplet superfield further decays into fermionic component of singlet superfield and quarks without violating baryon number. Imposing discrete Z2 symmetry, it follows that the singlet fermion will not further decay into the SM particles and therefore it can be considered as a stable asymmetric dark matter (ADM component. We find that the decay of the lightest eigenstate of scalar component of color triplet superfield gives the observed baryon asymmetry in the visible sector, an asymmetric dark matter component with the right abundance and naturally explains cosmic coincidence.

  2. Light moduli in almost no-scale models

    International Nuclear Information System (INIS)

    Buchmueller, Wilfried; Moeller, Jan; Schmidt, Jonas

    2009-09-01

    We discuss the stabilization of the compact dimension for a class of five-dimensional orbifold supergravity models. Supersymmetry is broken by the superpotential on a boundary. Classically, the size L of the fifth dimension is undetermined, with or without supersymmetry breaking, and the effective potential is of no-scale type. The size L is fixed by quantum corrections to the Kaehler potential, the Casimir energy and Fayet-Iliopoulos (FI) terms localized at the boundaries. For an FI scale of order M GUT , as in heterotic string compactifications with anomalous U(1) symmetries, one obtains L∝1/M GUT . A small mass is predicted for the scalar fluctuation associated with the fifth dimension, m ρ 3/2 /(L M). (orig.)

  3. Batrachotoxin-activated Na+ channels in planar lipid bilayers. Competition of tetrodotoxin block by Na+.

    Science.gov (United States)

    Moczydlowski, E; Garber, S S; Miller, C

    1984-11-01

    Single Na+ channels from rat skeletal muscle plasma membrane vesicles were inserted into planar lipid bilayers formed from neutral phospholipids and were observed in the presence of batrachotoxin. The batrachotoxin-modified channel activates in the voltage range -120 to -80 mV and remains open almost all the time at voltages positive to -60 mV. Low levels of tetrodotoxin (TTX) induce slow fluctuations of channel current, which represent the binding and dissociation of single TTX molecules to single channels. The rates of association and dissociation of TTX are both voltage dependent, and the association rate is competitively inhibited by Na+. This inhibition is observed only when Na+ is increased on the TTX binding side of the channel. The results suggest that the TTX receptor site is located at the channel's outer mouth, and that the Na+ competition site is not located deeply within the channel's conduction pathway.

  4. High-temperature phases of NaNbO3 and NaTaO3.

    Science.gov (United States)

    Darlington; Knight

    1999-02-01

    The high-temperature phases of the perovskites sodium niobate, NaNbO(3), and sodium tantalate, NaTaO(3), have been re-examined using the high-resolution powder diffractometer HRPD at the ISIS neutron spallation source; the two materials show the same sequence of phases with tilted octahedra. Diffraction patterns were measured every 5 K allowing structural changes with temperature within a single phase to be determined for the first time. Previous structure determinations within one phase had been performed at a single temperature only. The octahedra are tilted about pseudocubic directions and are also deformed; the magnitude of the deformation is shown to be proportional to the square of the angle of tilt as expected from a phenomenological theory applied to such transitions. The structures of NaNbO(3) between 753 and 793 K and of NaTaO(3) below 758 K are not as reported in the literature.

  5. Transmural gradients in Na/K pump activity and [Na+]I in canine ventricle.

    Science.gov (United States)

    Gao, J; Wang, W; Cohen, I S; Mathias, R T

    2005-09-01

    There are well-documented differences in ion channel activity and action potential shape between epicardial (EPI), midmyocardial (MID), and endocardial (ENDO) ventricular myocytes. The purpose of this study was to determine if differences exist in Na/K pump activity. The whole cell patch-clamp was used to measure Na/K pump current (I(P)) and inward background Na(+)-current (I(inb)) in cells isolated from canine left ventricle. All currents were normalized to membrane capacitance. I(P) was measured as the current blocked by a saturating concentration of dihydro-ouabain. [Na(+)](i) was measured using SBFI-AM. I(P)(ENDO) (0.34 +/- 0.04 pA/pF, n = 17) was smaller than I(P)(EPI) (0.68 +/- 0.09 pA/pF, n = 38); the ratio was 0.50 with I(P)(MID) being intermediate (0.53 +/- 0.13 pA/pF, n = 19). The dependence of I(P) on [Na(+)](i) or voltage was essentially identical in EPI and ENDO (half-maximal activation at 9-10 mM [Na(+)](i) or approximately -90 mV). Increasing [K(+)](o) from 5.4 to 15 mM caused both I(P)(ENDO) and I(P)(EPI) to increase, but the ratio remained approximately 0.5. I(inb) in EPI and ENDO were nearly identical ( approximately 0.6 pA/pF). Physiological [Na(+)](i) was lower in EPI (7 +/- 2 mM, n = 31) than ENDO (12 +/- 3 mM, n = 29), with MID being intermediate (9 +/- 3 mM, n = 22). When cells were paced at 2 Hz, [Na(+)](i) increased but the differences persisted (ENDO 14 +/- 3 mM, n = 10; EPI 9 +/- 2 mM, n = 10; and MID intermediate, 11 +/- 2 mM, n = 9). Based on these results, the larger I(P) in EPI appears to reflect a higher maximum turnover rate, which implies either a larger number of active pumps or a higher turnover rate per pump protein. The transmural gradient in [Na(+)](i) means physiological I(P) is approximately uniform across the ventricular wall, whereas transporters that utilize the transmembrane electrochemical gradient for Na(+), such as Na/Ca exchange, have a larger driving force in EPI than ENDO.

  6. Isotope separation of 22Na and 24Na with using light induced drift effect

    International Nuclear Information System (INIS)

    Hradecny, C.; Tethal, T.; Ermolaev, I.M.; Zemlyanoj, S.G.; Zuzaan, P.

    1993-01-01

    The LIDIS (Light Drift Isotope Separation) separator without a gas flow is discussed. It is shown, that atomization degree of the separated isotopes limited real separation coefficient. The better buffer gas purification allowed to increase the experimental separation factor of 22 Na and 24 Na isotopes up to 25. The new experimental set up allow to increase the separation efficiency up to 50%. 12 refs.; 5 figs

  7. Intracellular Na+ regulation of Na+ pump sites in cultured vascular smooth muscle cells

    International Nuclear Information System (INIS)

    Allen, J.C.; Navran, S.S.; Seidel, C.L.; Dennison, D.K.; Amann, J.M.; Jemelka, S.K.

    1989-01-01

    Enzymatically dispersed cells from canine saphenous vein and femoral artery were grown in fetal calf serum and studied at day 0 (freshly dispersed) through confluence in primary culture. Intracellular Na levels (Nai), but not intracellular K (Ki), were increased after 24 h in culture and then decreased to a steady state by 4 days. Na+ pump site number [( 3 H] ouabain binding) increased through day 3 and remained elevated. Nai was still elevated at 2 days when the Na+ pump site number began to increase. Total pump turnover (maximum ouabain-inhibited 86 Rb uptake) reflected the increase in Na+ pump site number. These key events precede the observed increases in both protein production and cellular proliferation. If the same cells are maintained in defined medium, without fetal calf serum, Nai, Ki, and the number of [ 3 H]ouabain binding sites do not change with time. These data are consistent with the suggestion that the initial mitogenic response of vascular smooth muscle cells to fetal calf serum involves an increased Na+ influx, and a Nai accumulation, caused by low Na+ pump density. The synthesis of new pump sites effects a decrease in the accumulated Nai, which may be related to cell proliferation

  8. Na+-NQR (Na+-translocating NADH:ubiquinone oxidoreductase) as a novel target for antibiotics.

    Science.gov (United States)

    Dibrov, Pavel; Dibrov, Elena; Pierce, Grant N

    2017-09-01

    The recent breakthrough in structural studies on Na+-translocating NADH:ubiquinone oxidoreductase (Na+-NQR) from the human pathogen Vibrio cholerae creates a perspective for the systematic design of inhibitors for this unique enzyme, which is the major Na+ pump in aerobic pathogens. Widespread distribution of Na+-NQR among pathogenic species, its key role in energy metabolism, its relation to virulence in different species as well as its absence in eukaryotic cells makes this enzyme especially attractive as a target for prospective antibiotics. In this review, the major biochemical, physiological and, especially, the pharmacological aspects of Na+-NQR are discussed to assess its 'target potential' for drug development. A comparison to other primary bacterial Na+ pumps supports the contention that NQR is a first rate prospective target for a new generation of antimicrobials. A new, narrowly targeted furanone inhibitor of NQR designed in our group is presented as a molecular platform for the development of anti-NQR remedies. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Active transport of Na/sup +/ by reconstituted Na,K-ATPase

    Energy Technology Data Exchange (ETDEWEB)

    Boldyrev, A.A.; Svinukhova, I.A.

    1987-02-20

    The ability of ATP, CTP, ITP, GTP, and UTP to support ouabain-sensitive accumulation of Na/sup +/ by proteoliposomes with a reconstituted Na/K-pump was investigated. At a low (Na/sup +/)/(K/sup +/) ratio in the medium (20 mM/50 mM), a correlation is observed between the proton-accepting capacity of the nucleotide and its effectiveness as a substrate of active transport. To test the hypothesis of the importance of the presence of a negative charge in the 1-position of the purine (3-pyrimidine) base of the nucleotide for mutual transitions between the Na- and K-conformations of Na,K-ATPase they used two analogs of ATP: N/sub 1/-hydroxy-ATP, possessing proton acceptor capacity, and N/sub 1/-methoxy-ATP, in the molecule of which the negative charge is quenched by a methyl group. The first substrate supports active accumulation of Na/sup +/ in proteoliposomes at the same rate as ATP, whereas the second substrate is relatively ineffective.

  10. Hidroginástica na terceira idade

    Directory of Open Access Journals (Sweden)

    Karla Campos de Paula

    1998-02-01

    Full Text Available O processo de envelhecimento no indivíduo saudável está relacionado com inúmeras alterações psicológicas e físicas que interferem na área motora, concorrendo para a inatividade e contribuindo para o aparecimento e agravamento de determinadas doenças, além de influenciar negativamente a realização das atividades de vida diária. Portanto, a prática de atividade física é fundamental para o idoso, não só na prevenção de doenças como na reabilitação de suas habilidades motoras, promovendo um estilo de vida saudável que é fator preponderante para a melhoria da qualidade de vida. Contudo, algumas precauções devem ser adotadas na prescrição da atividade direcionada para o idoso, a fim de que esta seja segura e prazerosa. Dentre os exercícios mais adequados aos idosos estão a caminhada, o ciclismo, a natação e a hidroginástica. Devido a sua grande procura, a hidroginástica vem aumentando o número de adeptos na terceira idade. Ela propicia ao idoso o aumento de sua capacidade aeróbia, força muscular, flexibilidade articular e o treinamento de habilidades específicas como equilíbrio e coordenação motora. Soma-se ainda o fato de esta atividade oferecer ambiente de relaxamento e incentivo ao contato social, atuando no combate ao estresse, depressão, na melhoria da autopercepção corporal e da auto-estima. Devemos, então, estar atentos às particularidades da hidroginástica, a fim de aproveitar todas as vantagens que esta oferece para o programa de exercícios direcionado para a terceira idade.

  11. Agmag Igbo dka Ngwar n'kwalite Ezi Nchekwa na Nkwsiike haobodo

    African Journals Online (AJOL)

    Ka Najira nwerechara onwe ya n'af 1960, olileanya tt mamala ya b na ihe ga-adz mma. Mana ka oge na-aga, a chptara na ihe na-akawanye nj. Usoro chch d iche iche daptara. Nd am na nd nkt achala mana nd gara n'ihu na-akawanye nj. O bu ihe doro anya na chch ha b nke nchgbu na fnfju akpa. N'agbanyegh na ...

  12. Transport of Na48 Drift Chambers to Dubna

    CERN Multimedia

    GOLOVATYUK, V

    2010-01-01

    On 22 July, in the occasion of the departure of the Na48 Drift Chambers from CERN, Mikhail Itkis (acting Director of the JIINR) and Rolf Heuer (CERN Director General) visited the NA62 experimental area.

  13. Angiotensin II-induced hypertension increases plasma membrane Na pump activity by enhancing Na entry in rat thick ascending limbs.

    Science.gov (United States)

    Gonzalez-Vicente, Agustin; Garvin, Jeffrey L

    2013-11-01

    Thick ascending limbs (TAL) reabsorb 30% of the filtered NaCl load. Na enters the cells via apical Na-K-2Cl cotransporters and Na/H exchangers and exits via basolateral Na pumps. Chronic angiotensin II (ANG II) infusion increases net TAL Na transport and Na apical entry; however, little is known about its effects on the basolateral Na pump. We hypothesized that in rat TALs Na pump activity is enhanced by ANG II-infusion, a model of ANG II-induced hypertension. Rats were infused with 200 ng·kg(-1)·min(-1) ANG II or vehicle for 7 days, and TAL suspensions were obtained. We studied plasma membrane Na pump activity by measuring changes in 1) intracellular Na (Nai) induced by ouabain; and 2) ouabain-sensitive oxygen consumption (QO2). We found that the ouabain-sensitive rise in Nai in TALs from ANG II-infused rats was 12.8 ± 0.4 arbitrary fluorescent units (AFU)·mg(-1)·min(-1) compared with only 9.9 ± 1.1 AFU·mg(-1)·min(-1) in controls (P Na pump expression, the number of Na pumps in the plasma membrane, or the affinity for Na. When furosemide (1.1 mg·kg(-1)·day(-1)) was coinfused with ANG II, no increase in plasma membrane Na pump activity was observed. We concluded that in ANG II-induced hypertension Na pump activity is increased in the plasma membrane of TALs and that this increase is caused by the chronically enhanced Na entry occurring in this model.

  14. Rescue of Na+ affinity in aspartate 928 mutants of Na+,K+-ATPase by secondary mutation of glutamate 314.

    Science.gov (United States)

    Holm, Rikke; Einholm, Anja P; Andersen, Jens P; Vilsen, Bente

    2015-04-10

    The Na(+),K(+)-ATPase binds Na(+) at three transport sites denoted I, II, and III, of which site III is Na(+)-specific and suggested to be the first occupied in the cooperative binding process activating phosphorylation from ATP. Here we demonstrate that the asparagine substitution of the aspartate associated with site III found in patients with rapid-onset dystonia parkinsonism or alternating hemiplegia of childhood causes a dramatic reduction of Na(+) affinity in the α1-, α2-, and α3-isoforms of Na(+),K(+)-ATPase, whereas other substitutions of this aspartate are much less disruptive. This is likely due to interference by the amide function of the asparagine side chain with Na(+)-coordinating residues in site III. Remarkably, the Na(+) affinity of site III aspartate to asparagine and alanine mutants is rescued by second-site mutation of a glutamate in the extracellular part of the fourth transmembrane helix, distant to site III. This gain-of-function mutation works without recovery of the lost cooperativity and selectivity of Na(+) binding and does not affect the E1-E2 conformational equilibrium or the maximum phosphorylation rate. Hence, the rescue of Na(+) affinity is likely intrinsic to the Na(+) binding pocket, and the underlying mechanism could be a tightening of Na(+) binding at Na(+) site II, possibly via movement of transmembrane helix four. The second-site mutation also improves Na(+),K(+) pump function in intact cells. Rescue of Na(+) affinity and Na(+) and K(+) transport by second-site mutation is unique in the history of Na(+),K(+)-ATPase and points to new possibilities for treatment of neurological patients carrying Na(+),K(+)-ATPase mutations. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Characterization of Na+-linked and Na+-independent Cl-/HCO3- exchange systems in Chinese hamster lung fibroblasts

    International Nuclear Information System (INIS)

    Cassel, D.; Scharf, O.; Rotman, M.; Cragoe, E.J. Jr.; Katz, M.

    1988-01-01

    The PS120 variant of Chinese hamster lung fibroblasts which lacks Na + /H + exchange activity was used to investigate bicarbonate transport systems and their role in intracellular pH (pH/sub i/) regulation. When pH/sub i/ was decreased by acid load, bicarbonate caused pH/sub i/ increase and stimulated 36 Cl - efflux from the cells, both in a Na + -dependent manner. These results together with previous findings that bicarbonate stimulates 22 Na + uptake in PS120 cells demonstrate the presence of a Na + -linked Cl - /HCO 3 - exchange system. In cells with normal initial pH/sub i/, bicarbonate caused Na + -independent pH/sub i/ increase in Cl - -free solutions and stimulated Na + -independent 36 Cl - efflux, indicating that a Na + -independent Cl - /HCO 3 - exchanger is also present in the cell. Na + -linked and Na + -independent Cl - /HCO 3- exchange is apparently mediated by two distinct systems, since a [(tetrahydrofluorene-7-yl)oxy]acetic acid derivative selectively inhibits the Na + -independent exchanger. An additional distinctive features is a 10-fold lower affinity for chloride of the Na + -linked exchanger. The Na + -linked and Na + -independent Cl - /HCO 3 - exchange systems are likely to protect the cell from acid and alkaline load, respectively

  16. The two C-terminal tyrosines stabilize occluded Na/K pump conformations containing Na or K ions.

    Science.gov (United States)

    Vedovato, Natascia; Gadsby, David C

    2010-07-01

    Interactions of the three transported Na ions with the Na/K pump remain incompletely understood. Na/K pump crystal structures show that the extended C terminus of the Na,K-adenosine triphosphatase (ATPase) alpha subunit directly contacts transmembrane helices. Deletion of the last five residues (KETYY in almost all Na/K pumps) markedly lowered the apparent affinity for Na activation of pump phosphorylation from ATP, a reflection of cytoplasmic Na affinity for forming the occluded E1P(Na3) conformation. ATPase assays further suggested that C-terminal truncations also interfere with low affinity Na interactions, which are attributable to extracellular effects. Because extracellular Na ions traverse part of the membrane's electric field to reach their binding sites in the Na/K pump, their movements generate currents that can be monitored with high resolution. We report here electrical measurements to examine how Na/K pump interactions with extracellular Na ions are influenced by C-terminal truncations. We deleted the last two (YY) or five (KESYY) residues in Xenopus laevis alpha1 Na/K pumps made ouabain resistant by either of two kinds of point mutations and measured their currents as 10-mM ouabain-sensitive currents in Xenopus oocytes after silencing endogenous Xenopus Na/K pumps with 1 microM ouabain. We found the low affinity inhibitory influence of extracellular Na on outward Na/K pump current at negative voltages to be impaired in all of the C-terminally truncated pumps. Correspondingly, voltage jump-induced transient charge movements that reflect pump interactions with extracellular Na ions were strongly shifted to more negative potentials; this signals a several-fold reduction of the apparent affinity for extracellular Na in the truncated pumps. Parallel lowering of Na affinity on both sides of the membrane argues that the C-terminal contacts provide important stabilization of the occluded E1P(Na3) conformation, regardless of the route of Na ion entry into the

  17. The rapid-onset dystonia parkinsonism mutation D923N of the Na+, K+-ATPase alpha3 isoform disrupts Na+ interaction at the third Na+ site.

    Science.gov (United States)

    Einholm, Anja Pernille; Toustrup-Jensen, Mads S; Holm, Rikke; Andersen, Jens Peter; Vilsen, Bente

    2010-08-20

    Rapid-onset dystonia parkinsonism (RDP), a rare neurological disorder, is caused by mutation of the neuron-specific alpha3-isoform of Na(+), K(+)-ATPase. Here, we present the functional consequences of RDP mutation D923N. Relative to the wild type, the mutant exhibits a remarkable approximately 200-fold reduction of Na(+) affinity for activation of phosphorylation from ATP, reflecting a defective interaction of the E(1) form with intracellular Na(+). This is the largest effect on Na(+) affinity reported so far for any Na(+), K(+)-ATPase mutant. D923N also affects the interaction with extracellular Na(+) normally driving the E(1)P to E(2)P conformational transition backward. However, no impairment of K(+) binding was observed for D923N, leading to the conclusion that Asp(923) is specifically associated with the third Na(+) site that is selective toward Na(+). The crystal structure of the Na(+), K(+)-ATPase in E(2) form shows that Asp(923) is located in the cytoplasmic half of transmembrane helix M8 inside a putative transport channel, which is lined by residues from the transmembrane helices M5, M7, M8, and M10 and capped by the C terminus, recently found involved in recognition of the third Na(+) ion. Structural modeling of the E(1) form of Na(+), K(+)-ATPase based on the Ca(2+)-ATPase crystal structure is consistent with the hypothesis that Asp(923) contributes to a site binding the third Na(+) ion. These results in conjunction with our previous findings with other RDP mutants suggest that a selective defect in the handling of Na(+) may be a general feature of the RDP disorder.

  18. Urgências reprodutivas na cadela

    OpenAIRE

    Costa, Teresa Isabel Rodrigues da

    2010-01-01

    Dissertação de Mestrado Integrado em Medicina Veterinária As urgências reprodutivas ocorrem com frequência na prática clínica, estando o seu desfecho favorável associado a um diagnóstico e intervenção céleres. Na cadela, consideram-se urgências reprodutivas a distócia, a piómetra, o prolapso uterino, a torção uterina, a tetania puerperal, a metrite e a mastite. Esta dissertação tem por base a análise dos dados referentes à casuística de urgências reprodutivas em cadelas veri...

  19. Jogos teatrais na escola pública

    Directory of Open Access Journals (Sweden)

    Ricardo Ottoni Vaz Japiassu

    1998-07-01

    Full Text Available O artigo apresenta os resultados parciais de pesquisa etnográfica que acompanha aspectos do desenvolvimento cultural de pré-adolescentes com a linguagem teatral em classe multisseriada, através do ensino regular de Teatro, em escola de ensino fundamental da rede pública estadual de São Paulo-SP. Os dados obtidos permitem afirmar que a linguagem cênica contribui na conscientização das novas possibilidades de significação da palavra na prática discursiva.The article shows partial results of ethnographic research in which kids are observed in their cultural development process with theater classes in public school education in São Paulo/Brazil. The data colected indicates that the use of theater games in school education helps students to be aware of a word’s new meaning possibilities in human comunication.

  20. HUME E O EMPIRISMO NA MORAL

    Directory of Open Access Journals (Sweden)

    Adriano Naves de Brito

    2007-12-01

    Full Text Available O que pretendo defender neste texto é que uma posição empirista na moral é compatível com uma pretensão de validade intersubjetiva de juízos morais. Essa pretensão deve, nesse caso, estar calcada na naturalização dos fundamentos da moralidade, mas tem de conviver com limites acerca da justificação de enunciados de valor. Para defender esse ponto, sirvo-me da filosofia moral de Hume, como ele a expôs no seu texto Uma investigação sobre os princípios da moral. No que diz respeito à filosofia de Hume, o objetivo deste texto é explicitar o caráter empírico seja de seu método de investigação da moral, seja do princípio que para ela ele encontra.

  1. News from the NA61/SHINE experiment

    Science.gov (United States)

    Šuša, Tatjana

    2018-02-01

    The main goals of the NA61/SHINE experiment at the CERN SPS are the search for the critical point of strongly interacting matter and the study of the properties of the onset of deconfinement. These aims are pursued by performing a two-dimensional scan of the phase diagram of strongly interacting matter by varying the momentum and size of the colliding nuclei. This contribution summarises the latest results from the NA61/SHINE experiment, in particular, new results on spectra and yields of ϕ meson in p+p interactions at 40, 80 and 158 GeV/c and K+ and K- production in central Be+Be collisions at mid-rapidity. In addition, results on system size dependence of particle yield ratios and fluctuations are presented.

  2. NA62 experiment at CERN SPS

    Directory of Open Access Journals (Sweden)

    Kozhuharov Venelin

    2014-01-01

    Full Text Available The NA62 experiment at SPS is a continuation of the long standing CERN kaon physics program. The high statistics and the unprecedent precision allow to probe the Standard Model and test the description of the strong interactions at low energy. The final results on the the lepton universality test by measuring the ratio RK = Γ(K+ → e+ν/Γ(K+ → µ+ν and the study of the K± → π±γγ decay are presented. The major goal of the NA62 experiment is to perform a measurement of the Br(K+ → π+νν̄ with a precision of 10% in two years of data taking. The detector setup together with the analysis technique is described.

  3. Luz e tempo na melancolia I

    Directory of Open Access Journals (Sweden)

    Cláudio Soares Braga Furtado

    2009-12-01

    Full Text Available A comparação entre as artes possibilita figurar o tempo como elemento comum entre a gravura renascentista de Dürer, a escultura romana de Laocoonte e o conto de Guimarães Rosa. A partir da leitura dessas artes distantes em forma, meios, época e lugar, descobrem-se mistérios aludidos em sutis sinais, que, se ainda não despertos na consciência criativa, estimulam interpretações. O papel da luz como unificadora das entidades tempo/espaço restabelece o princípio clássico da ut pictura poesis na leitura moderna.

  4. Kaizen: Uma Metodologia Inovadora na Siderurgia

    Directory of Open Access Journals (Sweden)

    Hericson Estanislau Prata

    2017-04-01

    Full Text Available A racionalização do processo produtivo industrial, por meio da redução dos desperdícios e da modernização do processo produtivo, com a adoção do Sistema Toyota de Produção (Produção Enxuta, tem sido adotada por uma parte importante das indústrias no mundo. O objetivo deste artigo é descrever essa metodologia empregada pelo grupo de melhoria de fase intensiva adotado na Vallourec Tubos do Brasil S.A. Como resultado, verificou-se que o processo utilizado para a implantação de mudanças em curto prazo foi a semana intensiva, também conhecida como evento Kaizen na indústria automotiva.

  5. O Personal Trainer na Perspectiva do Marketing

    Directory of Open Access Journals (Sweden)

    Cibele Biehl Bossle

    2011-03-01

    Full Text Available Esse estudo apresenta mapeamento das referências dedicadas à formação do personal trainer em bases de dados eletrônicas. Essa garimpagem revelou baixa produção científica sobre o assunto e mostrou que na literatura sobre personal trainer predominam livros com linguagem corrente no mundo dos negócios. Esses achados nos levaram a indagar sobre a força do discurso físico-empresarial, especialmente o marketing, na constituição desta ocupação profissional. Jeremy Rifkin, Zygmunt Bauman, Paula Sibilia e Denise Sant'Anna permitiram visualizar que o marketing dirigido ao personal trainer tem como tarefa reinventar, ressignificar e "repaginar" esta modalidade de serviço em nome da sobrevivência no disputado mercado da vida ativa.

  6. New NA22 results on correlations

    International Nuclear Information System (INIS)

    De Wolf, E.A.

    1993-01-01

    Recent NA22 results from π + p and K + p inelastic interactions at √s = 22 GeV on invariant-mass and Q 2 -dependence of two- and three-particle factorial cumulants are discussed in relation to earlier intermittency studies. The absence of Bose-Einstein type correlations among identical particles, and too large resonance production rates, are responsible for the strong disagreements of models with intermittency data. 6 figs., 17 refs

  7. NA35: sulphur-gold collision

    CERN Multimedia

    1991-01-01

    In this image the real particles produced by the collision of a 6400 GeV sulphur ion with a gold target can be seen as they pass through a streamer chamber. Streamer chambers consist of a gas chamber through which a strong pulsed electric field is passed, creating sparks as a charged particle passes through it. The NA35 experiment, which was in operation in the 1980s, was part of CERN's ongoing heavy ion project.

  8. Die Calvinistiese Sondagbeskouing met spesiale verwysing na ...

    African Journals Online (AJOL)

    omver te werp. Aan die ander kant het die orde en vrede in die kerk dit wel ook nodig gemaak om 'n dag vir gebruik van die diens van die Here af te sonder. Calvyn se insigte in verband met die oorgang van die Sabbat na die Sondag, is die insigte wat as die eg reformatoriese behoue gebly het. Haitjema (1961:249) sê in.

  9. Sources of Na for the Io atmosphere

    Science.gov (United States)

    Burnett, D. S.; Ellis, Susan B.; Rice, A.; Epstein, S.

    1993-01-01

    The physics and geology of Io have been extensively studied, but there has been little discussion of the chemistry. Relatively little is known about Io chemistry, but there are constraints. Further, it will be a long time before improvements will result from direct observation, given the severe difficulties with the Galileo mission. Via laboratory simulation experiments, plausible thermochemical and photochemical processes which determine the nature and amounts of surface constituents of Io are explored. The well-known density of Io shows that the planet overall is rocky. Because the orbit of Io is well within the magnetosphere of Jupiter and because Io only has a thin, transient SO2 atmosphere, the surface is continually sputtered with magnetospheric ions. Complex processes ionize and accelerate the Io surface atoms to keV and MeV energies. Remarkably, only S, O, and Na ions were found by Voyager. Sputtering also produces an atomic cloud of Na and S (O not observable) with a trace of K. Both gaseous and solid SO2 are known from spectroscopic studies. A trace of H2S and possibly CO2 are present. Geologic features are interpreted in terms of elemental S, but there is no direct evidence for this constituent. We thus have a rocky planet which does not have rocks on the surface. Our general goal is to understand the cycling of Na, S, and O through the crust and atmosphere on present-day Io and to understand how Io evolved to this state. A specific objective was to determine the phases on the surface which are the source of the Na in the atmosphere of Io.

  10. The NA48 liquid krypton calorimeter

    CERN Document Server

    Gorini, B

    1997-01-01

    The NA48 collaboration goal is to measure the CP violation parameter Re(ɛl/ɛ) at the level of 2 × 10−4. The neutral Kaon decays will be reconstructed by an electromagnetic liquid Krypton calorimeter with fine granularity and a volume almost totally sensible, to obtain excellent position and energy resolution, as well as time resolution. A description of the detector, results from tests of a prototype and the status of the final calorimeter are reported.

  11. Prototype calorimeters for the NA3 experiment

    CERN Multimedia

    1975-01-01

    The NA3 Experiment was set-up on the North Area of the SPS by the CERN/ Ecole Polytechnique/College de France/ Orsay/Saclay Collaboration, to study high transverse momentum leptons and hadrons from hadron collisions. The calorimeters measured the energy of hadrons (prototype on the right) and leptons (prototype on the left). They used a new type of plastic scintillator (plexipop). (see CERN Courier of November 1975) energy (prototype on the right)

  12. Maendeleo ya Fasihi ya Kiswahili ya Watoto nchini Tanzania na ...

    African Journals Online (AJOL)

    Fasihi ya Kiswahili ya watoto kama taaluma haina muda mrefu katika historia ya fasihi ya Kiswahili. Ikilinganishwa na fasihi ya watu wazima ambayo ilianza muda mrefu, na pia tafiti nyingi kufanyika katika mataifa mengi, fasihi ya watoto inaonekana kuwa imetelekezwa kwa muda mrefu kutokana na kutokupewa umuhimu ...

  13. Dhima za Mbinu Linganishi katika Kuhusisha Lugha na Lahaja ...

    African Journals Online (AJOL)

    Lengo la makala hii ni kujadili dhima za Mbinu Linganishi katika kuhusisha lugha na lahaja. Data za makala hii zilikusanywa kwa kutumia mbinu mbalimbali ambazo ni usaili, ushuhudiaji, hojaji na majadiliano katika majopo. Utafiti ulifanyika Tanzania Bara hususan Mkoani Mtwara na Tanzania Visiwani katika maeneo ya ...

  14. Glial Na(+) -dependent ion transporters in pathophysiological conditions.

    Science.gov (United States)

    Boscia, Francesca; Begum, Gulnaz; Pignataro, Giuseppe; Sirabella, Rossana; Cuomo, Ornella; Casamassa, Antonella; Sun, Dandan; Annunziato, Lucio

    2016-10-01

    Sodium dynamics are essential for regulating functional processes in glial cells. Indeed, glial Na(+) signaling influences and regulates important glial activities, and plays a role in neuron-glia interaction under physiological conditions or in response to injury of the central nervous system (CNS). Emerging studies indicate that Na(+) pumps and Na(+) -dependent ion transporters in astrocytes, microglia, and oligodendrocytes regulate Na(+) homeostasis and play a fundamental role in modulating glial activities in neurological diseases. In this review, we first briefly introduced the emerging roles of each glial cell type in the pathophysiology of cerebral ischemia, Alzheimer's disease, epilepsy, Parkinson's disease, Amyotrophic Lateral Sclerosis, and myelin diseases. Then, we discussed the current knowledge on the main roles played by the different glial Na(+) -dependent ion transporters, including Na(+) /K(+) ATPase, Na(+) /Ca(2+) exchangers, Na(+) /H(+) exchangers, Na(+) -K(+) -Cl(-) cotransporters, and Na(+) - HCO3- cotransporter in the pathophysiology of the diverse CNS diseases. We highlighted their contributions in cell survival, synaptic pathology, gliotransmission, pH homeostasis, and their role in glial activation, migration, gliosis, inflammation, and tissue repair processes. Therefore, this review summarizes the foundation work for targeting Na(+) -dependent ion transporters in glia as a novel strategy to control important glial activities associated with Na(+) dynamics in different neurological disorders. GLIA 2016;64:1677-1697. © 2016 Wiley Periodicals, Inc.

  15. Muundo wa Mashairi katika Diwani ya Mnyampala (1965) na Nafasi ...

    African Journals Online (AJOL)

    Makala hii pia inadadisi namna mbinu za kimuundo zilivyofanikisha usawiri na ubainishaji wa falsafa ya mtunzi kuhusu ushairi wa Kiswahili na nafasi ya ushairi katika jamii. Makala imeanza kwa kugusia usuli wa historia ya ushairi wa Kiswahili, historia fupi ya maisha ya Mathias Mnyampala na nadharia yake kuhusu ...

  16. Ujitokezaji wa Viambishi Njeo na Athari zake Kifonolojia katika ...

    African Journals Online (AJOL)

    Chanzo cha data za utafiti huu ni vitabu mbalimbali vinavyohusu lugha ya Shimalila, navyo vimeandikwa na watu mbalimbali wa jamii ya Shimalila ambao malengo yao ni kutafsiri Biblia kutoka katika lugha ya Kiswahili kwenda katika lugha ya Shimalila. Pia, data nyingine zimetokana na hojaji pamoja na usaili wa moja ...

  17. BAKITA NA LUGHA YA KUFUNDISHIA | BAKITA | Kioo cha Lugha

    African Journals Online (AJOL)

    BAKITA NA LUGHA YA KUFUNDISHIA. Baraza la Kiswahili la Taifa BAKITA. Abstract. Makala haya yanatoa maelezo mafupi ya matukio muhimu kuhusu suala la kutumia Kiswahili kama lugha ya kufundishia sekondari na vyuo katika kipindi baina ya mwaka 1967 mpaka 2000. Makala yanaeleza dhima na shughuli za ...

  18. Hadhi ya Kiswahili na watumiaji wake katika utandawazi ...

    African Journals Online (AJOL)

    Katika Taifa la Tanzania, mathalani, Kiswahili kimewakusanya na kuwajumuisha pamoja watu wa makabila zaidi ya 150 – kikitumika kama lugha ya mawasiliano inayoeleweka na watu wote. Hii si ajabu, ikizingatiwa kuwa, kwa silika yake, Kiswahili ni lugha unganishi, yaani yenye hulka ya kuunganisha, na siyo ya ...

  19. Hydrophilic C terminus of Salicornia europaea vacuolar Na/H ...

    Indian Academy of Sciences (India)

    Plant vacuolar Na+/H+ antiporters play important roles in cellular ion homeostasis,vacuolar pH regulation and sequestration of Na+ ions into the vacuole. Previous research showed that hydrophilic C-terminal region of Arabidopsis AtNHX1 negatively regulates the Na+/H+ transporting activity. In this study, we truncated the ...

  20. Fanfiction: uma escrita criativa na web

    Directory of Open Access Journals (Sweden)

    Daniele Alves Alencar

    Full Text Available RESUMO Estudo das fanfictions como uma prática de incentivo à leitura e produção de textos ficcionais na web. Por meio de pesquisa exploratória, bibliográfica e qualitativa foi desenvolvido o assunto para a área daCiência da Informação. Utiliza o site “Nyah! Fanfiction” como fonte de informação sobre as fanfictions e para aplicação de questionáriocomo auxílio na investigação do comportamento dos fanfiqueiros do site. O artigo mostra o que são as fanfictions, descreve a forma diferenciada que o ficwriterl ê o texto original para a produção da história, e apresenta o site “Nyah! Fanfiction” não apenas como depositário de fanfictions, mas também informa como essa prática pode se tornar mais que um passatempo, por explorar a imaginação, estimular a criação de textos, e assim intensificar a prática de leitura e escrita entre os jovens. O assunto estudado ainda é considerado novo na área de Biblioteconomia, portanto se faz necessário o desenvolvimento de mais pesquisas abordando o tema fanfiction.