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Sample records for interactive influence diagrams

  1. The Classroom as Rhizome: New Strategies for Diagramming Knotted Interactions

    ERIC Educational Resources Information Center

    de Freitas, Elizabeth

    2012-01-01

    This article calls attention to the unexamined role of diagrams in educational research and offers examples of alternative diagramming practices or tools that shed light on classroom interaction as a rhizomatic process. Drawing extensively on the work of Latour, Deleuze and Guattari, and Chatelet, this article explores the power of diagramming as…

  2. Influence diagrams as oil spill decision science tools

    EPA Science Inventory

    Making inferences on risks to ecosystem services (ES) from ecological crises can be more reliably handled using decision science tools. Influence diagrams (IDs) are probabilistic networks that explicitly represent the decisions related to a problem and evidence of their influence...

  3. Influence Diagram Use With Respect to Technology Planning and Investment

    NASA Technical Reports Server (NTRS)

    Levack, Daniel J. H.; DeHoff, Bryan; Rhodes, Russel E.

    2009-01-01

    Influence diagrams are relatively simple, but powerful, tools for assessing the impact of choices or resource allocations on goals or requirements. They are very general and can be used on a wide range of problems. They can be used for any problem that has defined goals, a set of factors that influence the goals or the other factors, and a set of inputs. Influence diagrams show the relationship among a set of results and the attributes that influence them and the inputs that influence the attributes. If the results are goals or requirements of a program, then the influence diagram can be used to examine how the requirements are affected by changes to technology investment. This paper uses an example to show how to construct and interpret influence diagrams, how to assign weights to the inputs and attributes, how to assign weights to the transfer functions (influences), and how to calculate the resulting influences of the inputs on the results. A study is also presented as an example of how using influence diagrams can help in technology planning and investment. The Space Propulsion Synergy Team (SPST) used this technique to examine the impact of R&D spending on the Life Cycle Cost (LCC) of a space transportation system. The question addressed was the effect on the recurring and the non-recurring portions of LCC of the proportion of R&D resources spent to impact technology objectives versus the proportion spent to impact operational dependability objectives. The goals, attributes, and the inputs were established. All of the linkages (influences) were determined. The weighting of each of the attributes and each of the linkages was determined. Finally the inputs were varied and the impacts on the LCC determined and are presented. The paper discusses how each of these was accomplished both for credibility and as an example for future studies using influence diagrams for technology planning and investment planning.

  4. Phase diagram of two interacting helical states

    NASA Astrophysics Data System (ADS)

    Santos, Raul A.; Gutman, D. B.; Carr, Sam T.

    2016-06-01

    We consider two coupled time-reversal-invariant helical edge modes of the same helicity, such as would occur on two stacked quantum spin Hall insulators. In the presence of interaction, the low-energy physics is described by two collective modes, one corresponding to the total current flowing around the edge and the other one describing relative fluctuations between the two edges. We find that quite generically, the relative mode becomes gapped at low temperatures, but only when tunneling between the two helical modes is nonzero. There are two distinct possibilities for the gapped state depending on the relative size of different interactions. If the intraedge interaction is stronger than the interedge interaction, the state is characterized as a spin-nematic phase. However, in the opposite limit, when the interaction between the helical edge modes is strong compared to the interaction within each mode, a spin-density wave forms, with emergent topological properties. First, the gap protects the conducting phase against localization by weak nonmagnetic impurities; second, the protected phase hosts localized zero modes on the ends of the edge that may be created by sufficiently strong nonmagnetic impurities.

  5. Use of influence diagrams in gas transfer system option prioritization

    SciTech Connect

    Heger, A.S.; Garcia, M.D.

    1995-08-01

    A formal decision-analysis methodology was applied to aid the Department of Energy (DOE) in deciding which of several gas transfer system (GTS) options should be selected. The decision objectives for this case study, i.e., risk and cost, were directly derived from the DOE guidelines. Influence diagrams were used to define the structure of the decision problem and clearly delineate the flow if information. A set of performance matrices wee used in conjunction with the influence diagrams to assess and evaluate the degree to which the objectives of the case study were met. These performance measures were extracted from technical models, design and operating data, and professional judgments. The results were aggregated to provide an overall evaluation of the different design options of the gas transfer system. Consequently, the results of this analysis were used as an aid to DOE to select a viable GTS option.

  6. Phase diagram and critical end point for strongly interacting quarks.

    PubMed

    Qin, Si-xue; Chang, Lei; Chen, Huan; Liu, Yu-xin; Roberts, Craig D

    2011-04-29

    We introduce a method based on chiral susceptibility, which enables one to draw a phase diagram in the chemical-potential-temperature plane for strongly interacting quarks whose interactions are described by any reasonable gap equation, even if the diagrammatic content of the quark-gluon vertex is unknown. We locate a critical end point at (μ(E),T(E))∼(1.0,0.9)T(c), where T(c) is the critical temperature for chiral-symmetry restoration at μ=0, and find that a domain of phase coexistence opens at the critical end point whose area increases as a confinement length scale grows.

  7. Phase diagram and entanglement of two interacting topological Kitaev chains

    NASA Astrophysics Data System (ADS)

    Herviou, Loïc; Mora, Christophe; Le Hur, Karyn

    2016-04-01

    A superconducting wire described by a p -wave pairing and a Kitaev Hamiltonian exhibits Majorana fermions at its edges and is topologically protected by symmetry. We consider two Kitaev wires (chains) coupled by a Coulomb-type interaction and study the complete phase diagram using analytical and numerical techniques. A topological superconducting phase with four Majorana fermions occurs until moderate interactions between chains. For large interactions, both repulsive and attractive, by analogy with the Hubbard model, we identify Mott phases with Ising-type magnetic order. For repulsive interactions, the Ising antiferromagnetic order favors the occurrence of orbital currents spontaneously breaking time-reversal symmetry. By strongly varying the chemical potentials of the two chains, quantum phase transitions towards fully polarized (empty or full) fermionic chains occur. In the Kitaev model, the quantum critical point separating the topological superconducting phase and the polarized phase belongs to the universality class of the critical Ising model in two dimensions. When increasing the Coulomb interaction between chains, then we identify an additional phase corresponding to two critical Ising theories (or two chains of Majorana fermions). We confirm the existence of such a phase from exact mappings and from the concept of bipartite fluctuations. We show the existence of negative logarithmic corrections in the bipartite fluctuations, as a reminiscence of the quantum critical point in the Kitaev model. Other entanglement probes such as bipartite entropy and entanglement spectrum are also used to characterize the phase diagram. The limit of large interactions can be reached in an equivalent setup of ultracold atoms and Josephson junctions.

  8. Phase diagram of harmonically confined one-dimensional fermions with attractive and repulsive interactions

    SciTech Connect

    Campo, V. L. Jr.; Capelle, K.

    2005-12-15

    We construct the complete U-{mu} phase diagram for harmonically confined ultracold fermionic atoms with repulsive and attractive interactions({mu} is the chemical potential and U the interaction strength). Our approach is based on density-functional theory, and employs analytical expressions for the kinetic and correlation energy functionals, permitting us to obtain closed expressions for all phase boundaries and characteristic lines of the phase diagram, both for repulsive and attractive interactions.

  9. Influence Diagrams as Decision-Making Tools for Pesticide Risk Management

    EPA Science Inventory

    The pesticide policy arena is filled with discussion of probabilistic approaches to assess ecological risk, however, similar discussions about implementing formal probabilistic methods in pesticide risk decision making are less common. An influence diagram approach is proposed f...

  10. Phase diagrams for the adsorption of monomers with non-additive interactions

    NASA Astrophysics Data System (ADS)

    Pinto, O. A.; Ramirez-Pastor, A. J.; Nieto, F.

    2016-09-01

    In several experimental systems phase diagrams coverage-temperature show a strong asymmetry. This behavior can be reproduced by including non-additive lateral interactions. In this work a Monte Carlo study on the canonical assembly of the criticality of monomer adsorption with non-additive interactions is presented. Traditional pairwise energies were replaced by other more general ones where the lateral interaction between two ad-atoms depends on the coverage at first sphere of coordination. This kind of energies includes multibody interactions like three-body interactions and four-body interactions, etc. These energies induce the formation of several non-additive ordered structures. Finite size scaling method was used to classify the order of phase transition of each non-additive phase. On the other hand, the corresponding phase diagrams are formed naturally, in which case the diagrams show strong asymmetries.

  11. Minimizing risks from spilled oil to ecosystem services using influence diagrams: The Deepwater Horizon spill response

    EPA Science Inventory

    Making inferences on risks to ecosystem services (ES) from ecological crises may be improved using decision science tools. Influence diagrams (IDs) are probabilistic networks that explicitly represent the decisions related to a problem and evidence of their influence on desired o...

  12. Water Mediated Interactions and the Protein Folding Phase Diagram in the Temperature-Pressure Plane.

    PubMed

    Sirovetz, Brian J; Schafer, Nicholas P; Wolynes, Peter G

    2015-08-27

    The temperature-pressure behavior of two proteins, ubiquitin and λ-repressor, is explored using a realistically coarse-grained physicochemical model, the associative memory, water mediated, structure and energy model (AWSEM). The phase diagram across the temperature-pressure plane is obtained by perturbing the water mediated interactions in the Hamiltonian systematically. The phase diagrams calculated with direct simulations along with an extended bridge sampling estimator show the main features found experimentally, including both cold- and pressure-denaturation. The denatured ensembles in different parts of the phase diagram are characterized and found to be structurally distinct. The protein energy landscape is found to be funneled throughout the phase diagram, but modest changes in the entropy and free energy of the water are found to drive both cold and pressure induced denaturation. PMID:26102155

  13. Minimizing risks from spilled oil to ecosystem services using influence diagrams: the Deepwater Horizon spill response.

    PubMed

    Carriger, John F; Barron, Mace G

    2011-09-15

    Decision science tools can be used in evaluating response options and making inferences on risks to ecosystem services (ES) from ecological disasters. Influence diagrams (IDs) are probabilistic networks that explicitly represent the decisions related to a problem and their influence on desired or undesired outcomes. To examine how IDs might be useful in probabilistic risk management for spill response efforts, an ID was constructed to display the potential interactions between exposure events and the trade-offs between costs and ES impacts from spilled oil and response decisions in the DWH spill event. Quantitative knowledge was not formally incorporated but an ID platform for doing this was examined. Probabilities were assigned for conditional relationships in the ID and scenarios examining the impact of different response actions on components of spilled oil were investigated in hypothetical scenarios. Given the structure of the ID, potential knowledge gaps included understanding of the movement of oil, the ecological risk of different spill-related stressors to key receptors (e.g., endangered species, fisheries), and the need for stakeholder valuation of the ES benefits that could be impacted by a spill. Framing the Deepwater Horizon problem domain in an ID conceptualized important variables and relationships that could be optimally accounted for in preparing and managing responses in future spills. These features of the developed IDs may assist in better investigating the uncertainty, costs, and the trade-offs if large-scale, deep ocean spills were to occur again.

  14. Solving Algebra Problems with Interactive Diagrams: Demonstration and Construction of Examples

    ERIC Educational Resources Information Center

    Naftaliev, Elena; Yerushalmy, Michal

    2011-01-01

    We investigated how students use the representation of data in a given example appearing in an interactive diagram (ID) and how they create additional examples with the ID. Students who worked with the ID that offered limited representations and tools ("illustrating ID") looked for ways to bypass the designed constraints: they changed the…

  15. Magnetic phase diagram of interacting nanoparticle systems under the mean-field model

    NASA Astrophysics Data System (ADS)

    Mao, Zhongquan; Chen, Xi

    2011-06-01

    The disordered random-anisotropy magnetic nanoparticle systems with competing dipolar interactions and ferromagnetic exchange couplings are investigated by Monte Carlo simulations. Superspin glass (SSG) and superferromagnetic (SFM) behaviors are found at low temperatures depending on the interactions. Based on the mean-field approximation, the Curie-Weiss temperature TCW = 0 is suggested as the phase boundary between the SSG systems and the SFM systems, which is evidenced by the spontaneous magnetizations and relaxations. The magnetic phase diagram is plotted.

  16. Application of influence diagrams to prostate intensity-modulated radiation therapy plan selection

    NASA Astrophysics Data System (ADS)

    Meyer, Jürgen; Phillips, Mark H.; Cho, Paul S.; Kalet, Ira; Doctor, Jason N.

    2004-05-01

    The purpose is to incorporate clinically relevant factors such as patient-specific and dosimetric information as well as data from clinical trials in the decision-making process for the selection of prostate intensity-modulated radiation therapy (IMRT) plans. The approach is to incorporate the decision theoretic concept of an influence diagram into the solution of the multiobjective optimization inverse planning problem. A set of candidate IMRT plans was obtained by varying the importance factors for the planning target volume (PTV) and the organ-at-risk (OAR) in combination with simulated annealing to explore a large part of the solution space. The Pareto set for the PTV and OAR was analysed to demonstrate how the selection of the weighting factors influenced which part of the solution space was explored. An influence diagram based on a Bayesian network with 18 nodes was designed to model the decision process for plan selection. The model possessed nodes for clinical laboratory results, tumour grading, staging information, patient-specific information, dosimetric information, complications and survival statistics from clinical studies. A utility node was utilized for the decision-making process. The influence diagram successfully ranked the plans based on the available information. Sensitivity analyses were used to judge the reasonableness of the diagram and the results. In conclusion, influence diagrams lend themselves well to modelling the decision processes for IMRT plan selection. They provide an excellent means to incorporate the probabilistic nature of data and beliefs into one model. They also provide a means for introducing evidence-based medicine, in the form of results of clinical trials, into the decision-making process.

  17. Phase diagram for a cubic-Q interacting boson model Hamiltonian: Signs of triaxiality

    SciTech Connect

    Fortunato, L.; Alonso, C. E.; Arias, J. M.; Garcia-Ramos, J. E.; Vitturi, A.

    2011-07-15

    An extension of the Interacting Boson Model that includes the cubic (QxQxQ){sup (0)} term is proposed. The potential energy surface for the cubic quadrupole interaction is explicitly calculated within the coherent state formalism using the complete ({chi}-dependent) expression for the quadrupole operator. The Q-cubic term is found to depend on the asymmetry deformation parameter {gamma} as a linear combination of cos(3{gamma}) and cos{sup 2}(3{gamma}) terms, thereby allowing for triaxiality. The phase diagram of the model in the large N limit is explored: The orders of the phase transition surfaces that define the phase diagram are described, and the possible nuclear equilibrium shapes are established. It is found that for this particular Hamiltonian, contrary to expectations, there is only a very tiny region of triaxiality, and that the transition from prolate to oblate shapes is so fast that, in most cases, the onset of triaxiality might go unnoticed.

  18. Interacting bosons in a disordered lattice: Dynamical characterization of the quantum phase diagram

    NASA Astrophysics Data System (ADS)

    Buonsante, Pierfrancesco; Pezzè, Luca; Smerzi, Augusto

    2015-03-01

    We study the quantum dynamics of interacting bosons in a three-dimensional disordered lattice. We show that the superfluid current induced by an adiabatic acceleration of the disordered lattice undergoes a dynamical instability signaling the onset of the Bose-glass phase. The dynamical superfluid-Bose-glass phase diagram is found in very good agreement with static superfluid fraction calculation. A different boundary is obtained when the disorder is suddenly quenched in a moving periodic lattice. In this case we do not observe a dynamical instability but rather a depletion of the superfluid density. Our analysis is based on a dynamical Gutzwiller approach which we show to reproduce the quantum Monte Carlo static phase diagram in the strong interaction limit.

  19. Potential application of influence diagram as a risk assessment tool in Brownfields sites

    SciTech Connect

    Attoh-Okine, N.O.

    1998-12-31

    Brownfields are vacant, abandoned, or underutilized commercial and industrial sites and facilities where real or perceived environmental contamination is an obstacle to redevelopment. These sites are vacant because they often do not meet the strict remediation requirements of the Superfund Law. The sites are accessible locations with much of the infrastructure, albeit deteriorated, in place. Thus they also represent an opportunity to slow down suburban and rural sprawl. As a liability, the concern stems from the environment liability of both known and unknown site contamination. Influence diagrams are tools used to represent complex decision problems based on incomplete and uncertain information from a variety of sources. The influence diagrams can be used to divide all uncertainties (Brownfields site infrastructure impact assessment) into subfactors until the level has been reached at which intuitive functions are most effective. Given the importance of uncertainties and the utilities of the Brownfields infrastructure, the use of influence diagrams seem more appropriate for representing and solving risks involved in Brownfields infrastructure assessment.

  20. Computational Study of Sulfur–nickel Interactions: A New S–Ni Phase Diagram

    SciTech Connect

    Wang, Jeng-Han; Liu, Meilin

    2007-06-22

    Prediction of the interactions between H2S-contaminated hydrogen fuel and Ni surfaces under conditions similar to those for solid oxide fuel cell (SOFC) operation using DFT (density function theory) calculations (with thermodynamic corrections) has resulted in a new S–Ni phase diagram, which suggests the existence of an intermediate state between clean Ni surfaces and nickel sulfides – sulfur atoms adsorbed on Ni surfaces. This prediction is consistent with many experimental observations relevant to sulfur poisoning of Nibased anodes in SOFCs, which cannot be explained using the existing S–Ni bulk phase diagram from classical thermodynamics. The accurate prediction of the adsorption phase is vital to a fundamental understanding of the sulfur poisoning mechanism of Ni-based anodes under SOFC operating conditions.

  1. Exact thermodynamics and phase diagram of integrable t-J model with chiral interaction

    NASA Astrophysics Data System (ADS)

    Tavares, T. S.; Ribeiro, G. A. P.

    2016-09-01

    We study the phase diagram and finite temperature properties of an integrable generalization of the one-dimensional super-symmetric t-J model containing interactions explicitly breaking parity-time reversal (PT) symmetries. To this purpose, we apply the quantum transfer matrix method which results in a finite set of non-linear integral equations. We obtain numerical solutions to these equations leading to results for thermodynamic quantities as a function of temperature, magnetic field, particle density and staggering parameter. Studying the maxima lines of entropy at low but non zero temperature reveals the phase diagram of the model. There are ten different phases which we may classify in terms of the qualitative behaviour of auxiliary functions, closely related to the dressed energy functions.

  2. Quantized Pumping and Topology of the Phase Diagram for a System of Interacting Bosons

    NASA Astrophysics Data System (ADS)

    Berg, Erez; Levin, Michael; Altman, Ehud

    2011-03-01

    Interacting lattice bosons at integer filling can support two distinct insulating phases, which are separated by a critical point: the Mott insulator and the Haldane insulator [E. G. Dalla Torre, E. Berg, and E. Altman, Phys. Rev. Lett. 97, 260401 (2006).PRLTAO0031-900710.1103/PhysRevLett.97.260401]. The critical point can be gapped out by breaking lattice inversion symmetry. Here, we show that encircling this critical point adiabatically pumps one boson across the system. When multiple chains are coupled, the two insulating phases are no longer sharply distinct, but the pumping property survives. This leads to strict constraints on the topology of the phase diagram of systems of quasi-one-dimensional interacting bosons.

  3. Phase diagram of Rydberg atoms with repulsive van der Waals interaction

    SciTech Connect

    Osychenko, O. N.; Astrakharchik, G. E.; Boronat, J.; Lutsyshyn, Y.; Lozovik, Yu. E.

    2011-12-15

    We report a quantum Monte Carlo calculation of the phase diagram of bosons interacting with a repulsive inverse sixth power pair potential, a model for assemblies of Rydberg atoms in the local van der Waals blockade regime. The model can be parametrized in terms of just two parameters, the reduced density and temperature. Solidification happens to the fcc phase. At zero temperature, the transition density is found with the diffusion Monte Carlo method at density {rho}=3.9 (({Dirac_h}/2{pi}){sup 2}/mC{sub 6}){sup 3/4}, where C{sub 6} is the strength of the interaction. The solidification curve at nonzero temperature is studied with the path-integral Monte Carlo approach and is compared with transitions in corresponding harmonic and classical crystals. Relaxation mechanisms are considered in relation to present experiments.

  4. First-order reversal curve diagrams of magnetic entities with mean interaction field: A physical analysis perspective

    NASA Astrophysics Data System (ADS)

    Béron, Fanny; Ménard, David; Yelon, Arthur

    2008-04-01

    A new approach to the quantitative and physical analysis of first-order reversal curve (FORC) diagrams is presented. Each hysteron in the FORC method represents a magnetic cluster. Starting with a model for a ferromagnetic, isotropic, and monodomain sphere, and adding anisotropy and domain structure, three different types of "basic hysterons" are obtained: vertical reversible and irreversible, and linear. The FORC diagrams of basic hysterons with a mean interaction field were obtained by simulation. From them, the relationships between the characteristics of the hysterons and the FORC distribution function were extracted. Different sets of hysterons can lead to the same FORC distribution function. A positive mean interaction field tends to merge the hysterons on the FORC diagram, while a negative mean interaction field introduces repulsion between them.

  5. The phase diagram in the SU(3) Nambu-Jona-Lasinio model with 't Hooft and eight-quark interactions

    SciTech Connect

    Moreira, J.; Hiller, B.; Blin, A. H.; Osipov, A. A.

    2010-08-05

    It is shown that the endpoint of the first order transition line which merges into a crossover regime in the phase diagram of the Nambu--Jona-Lasinio model, extended to include the six-quark 't Hooft and eight-quark interaction Lagrangians, is pushed towards vanishing chemical potential and higher temperatures with increasing strength of the OZI-violating eight-quark interactions. We clarify a connection between the location of the endpoint in the phase diagram and the mechanism of chiral symmetry breaking at the quark level. Constraints on the coupling strengths based on groundstate stability and physical considerations are explained.

  6. Bridging and depletion mechanisms in colloid-colloid effective interactions: A reentrant phase diagram.

    PubMed

    Fantoni, Riccardo; Giacometti, Achille; Santos, Andrés

    2015-06-14

    A general class of nonadditive sticky-hard-sphere binary mixtures, where small and large spheres represent the solvent and the solute, respectively, is introduced. The solute-solute and solvent-solvent interactions are of hard-sphere type, while the solute-solvent interactions are of sticky-hard-sphere type with tunable degrees of size nonadditivity and stickiness. Two particular and complementary limits are studied using analytical and semi-analytical tools. The first case is characterized by zero nonadditivity, lending itself to a Percus-Yevick approximate solution from which the impact of stickiness on the spinodal curves and on the effective solute-solute potential is analyzed. In the opposite nonadditive case, the solvent-solvent diameter is zero and the model can then be reckoned as an extension of the well-known Asakura-Oosawa model with additional sticky solute-solvent interaction. This latter model has the property that its exact effective one-component problem involves only solute-solute pair potentials for size ratios such that a solvent particle fits inside the interstitial region of three touching solutes. In particular, we explicitly identify the three competing physical mechanisms (depletion, pulling, and bridging) giving rise to the effective interaction. Some remarks on the phase diagram of these two complementary models are also addressed through the use of the Noro-Frenkel criterion and a first-order perturbation analysis. Our findings suggest reentrance of the fluid-fluid instability as solvent density (in the first model) or adhesion (in the second model) is varied. Some perspectives in terms of the interpretation of recent experimental studies of microgels adsorbed onto large polystyrene particles are discussed.

  7. Bridging and depletion mechanisms in colloid-colloid effective interactions: A reentrant phase diagram

    NASA Astrophysics Data System (ADS)

    Fantoni, Riccardo; Giacometti, Achille; Santos, Andrés

    2015-06-01

    A general class of nonadditive sticky-hard-sphere binary mixtures, where small and large spheres represent the solvent and the solute, respectively, is introduced. The solute-solute and solvent-solvent interactions are of hard-sphere type, while the solute-solvent interactions are of sticky-hard-sphere type with tunable degrees of size nonadditivity and stickiness. Two particular and complementary limits are studied using analytical and semi-analytical tools. The first case is characterized by zero nonadditivity, lending itself to a Percus-Yevick approximate solution from which the impact of stickiness on the spinodal curves and on the effective solute-solute potential is analyzed. In the opposite nonadditive case, the solvent-solvent diameter is zero and the model can then be reckoned as an extension of the well-known Asakura-Oosawa model with additional sticky solute-solvent interaction. This latter model has the property that its exact effective one-component problem involves only solute-solute pair potentials for size ratios such that a solvent particle fits inside the interstitial region of three touching solutes. In particular, we explicitly identify the three competing physical mechanisms (depletion, pulling, and bridging) giving rise to the effective interaction. Some remarks on the phase diagram of these two complementary models are also addressed through the use of the Noro-Frenkel criterion and a first-order perturbation analysis. Our findings suggest reentrance of the fluid-fluid instability as solvent density (in the first model) or adhesion (in the second model) is varied. Some perspectives in terms of the interpretation of recent experimental studies of microgels adsorbed onto large polystyrene particles are discussed.

  8. Bridging and depletion mechanisms in colloid-colloid effective interactions: A reentrant phase diagram.

    PubMed

    Fantoni, Riccardo; Giacometti, Achille; Santos, Andrés

    2015-06-14

    A general class of nonadditive sticky-hard-sphere binary mixtures, where small and large spheres represent the solvent and the solute, respectively, is introduced. The solute-solute and solvent-solvent interactions are of hard-sphere type, while the solute-solvent interactions are of sticky-hard-sphere type with tunable degrees of size nonadditivity and stickiness. Two particular and complementary limits are studied using analytical and semi-analytical tools. The first case is characterized by zero nonadditivity, lending itself to a Percus-Yevick approximate solution from which the impact of stickiness on the spinodal curves and on the effective solute-solute potential is analyzed. In the opposite nonadditive case, the solvent-solvent diameter is zero and the model can then be reckoned as an extension of the well-known Asakura-Oosawa model with additional sticky solute-solvent interaction. This latter model has the property that its exact effective one-component problem involves only solute-solute pair potentials for size ratios such that a solvent particle fits inside the interstitial region of three touching solutes. In particular, we explicitly identify the three competing physical mechanisms (depletion, pulling, and bridging) giving rise to the effective interaction. Some remarks on the phase diagram of these two complementary models are also addressed through the use of the Noro-Frenkel criterion and a first-order perturbation analysis. Our findings suggest reentrance of the fluid-fluid instability as solvent density (in the first model) or adhesion (in the second model) is varied. Some perspectives in terms of the interpretation of recent experimental studies of microgels adsorbed onto large polystyrene particles are discussed. PMID:26071729

  9. Interacting massive binaries, HR-diagram of the LMC and SN1987A

    NASA Astrophysics Data System (ADS)

    Rathnasree, N.

    1993-05-01

    The observational constraints on massive star models for the LMC arise essentially from (1) the distribution of stars in the HR-diagram of the LMC, (2) the observations of SN 1987A and its progenitor and (3) from the determinations of surface abundances of certain blue supergiants in the LMC which are seen to be helium and nitrogen enriched. The standard physical inputs used in single star evolutionary models do not give good agreement with these observational constraints. The study of interacting binary stars, taking into account the effect of the transfer of CNO processed and helium enriched material to the secondaries in these systems, reveals that the presence of a substantial fraction of such stars in the BSG region in the HR-diagram of the LMC gives good agreement with the observational constraints discussed above. Mass transfer to the secondary while it is still within its main-sequence could give an evolutionary model at 20 M_⊙ which stays in the blue through out its lifetime and yet could show helium enrichment and CNO processing in its circumstellar material and the envelope of the star consistent with the observations of SN1987A. However, a more consistent model for the progenitor is obtained if the component masses are nearly equal and the secondary star accretes matter from the primary after it evolves to the Hayashi track. The presence of highly helium and nitrogen enriched BSG stars at high temperatures is shown to arise as a natural consequence of interacting binary star evolution, a feature in general difficult to reconcile with all the existing evolutionary models. It is predicted that these stars should be abundant at high temperatures close to the main-sequence while lower temperature regions should be populated by stars with moderate helium and nitrogen enrichment. This research was partially supported by 8(th) Five year plan project 8P-45 at TIFR, India. Supercomputing time on the CRAY XMP and YMP at the University of Illinois is

  10. Gender Influences in Classroom Interaction.

    ERIC Educational Resources Information Center

    Wilkinson, Louise Cherry, Ed.; Marrett, Cora B., Ed.

    The 11 chapters comprising this work focus on the interactional influences that may be related to differential classroom experiences for males and females. The effects of contextual factors, teacher characteristics, and student characteristics are investigated. Addressed primarily to researchers, this information should prove useful to teachers,…

  11. Influence of V-Diagrams on 10th Grade Turkish Students' Achievement in the Subject of Mechanical Waves

    ERIC Educational Resources Information Center

    Tekes, Hanife; Gonen, Selahattin

    2012-01-01

    The purpose of the present study was to examine how the use of V-diagrams one of the learning techniques used in laboratory studies in experiments conducted regarding the 10th grade lesson unit of "waves" influenced students' achievements. In the study, a quasi-experimental design with a pretest and posttest control group was used. The study was…

  12. Characteristic correlations between the Δm* interaction curves and the Preisach diagram in particulate media

    NASA Astrophysics Data System (ADS)

    Bottoni, G.; Candolfo, D.; Cecchetti, A.

    2002-05-01

    Magnetic interparticle interactions are analyzed by Δm* curves calculated from the initial magnetization curve and the hysteresis loop, instead of the usual deviation Δm based on remanence curves. This study is made on tapes of acicular CrO2 particles and on tapes of CoTi-doped Ba ferrite platelet-shaped particles. The standard Preisach map of the samples is experimentally constructed and the Δm* values, computed from this map, and the values agree fairly well with the Δm* curves measured for the ac demagnetized state and various dc demagnetized states. We describe a procedure for remagnetizing the dc demagnetized samples. For the acicular particles, the peak of the remagnetized curves is lower than that computed from the Preisach map. The opposite occurs for the platelet-shaped particles. This different behavior is ascribed to the different influence of the statistical interaction field and the mean interaction field.

  13. The phase diagram of a directed polymer in random media with p-spin ferromagnetic interactions

    NASA Astrophysics Data System (ADS)

    Wedagedera, J. R.

    2011-01-01

    We consider a directed polymer model with an additive p-spin (p>2) ferromagnetic term in the Hamiltonian. We give a rigorous proof for the specific free energy and derive the phase diagram. This model was proposed previously, and a detailed proof was given in the case p = 2, while the main result was only stated for p > 2. We give a detailed proof of the main result and show the behavior of the model as p → ∞ by constructing the phase diagram also in this case. These results are important in many applications, for instance, in telecommunication and immunology. Our major finding is that in the phase diagram for p > 2, a new transition curve (absent for p = 2) emerges between the paramagnetic region and the so-called mixed region and that the ferromagnetic region diminishes as p → ∞.

  14. Effect of Dzyaloshinskii-Moriya interaction on phase diagrams of spin-1 Heisenberg-Ising alternating chains

    NASA Astrophysics Data System (ADS)

    Liu, Guang-Hua; Dou, Jun-Ya; Lu, Peng

    2016-03-01

    The effect of the Dzyaloshinskii-Moriya interaction (DMI) on ground-state phase diagrams of spin-1 Heisenberg-Ising alternating chains is investigated by the infinite time-evolving block decimation method. Three rich phase diagrams for three cases with different DMIs are obtained and discussed systematically. The DMI on even bonds plays a key role in the ground-state phase diagram, especially the appearance of the Haldane phase. However, the DMI on odd bonds seems to have very weak effect on the phase diagram. Both the odd- and even-string orders become nonzero in the Haldane phase, and have their maximum values at θ = π. For the odd-dimer phase, the even-string correlator vanishes absolutely despite varying θ, but a double-peak structure of the odd-string correlator is observed. Odd-string correlator becomes maximum at θ = π / 2 and 3 π / 2, but vanishes at θ = π. It indicates that the generalized string correlator can be used to distinguish the odd-dimer from the Haldane phase. Doubly degenerate entanglement spectrum is observed in the Haldane phase, which can be regarded as a clear signature of the existence of topological orders. Strong enough transverse nearest-neighbor correlations are found to be very important for the appearance of the Haldane and the odd-dimer phases.

  15. Teaching Electron--Positron--Photon Interactions with Hands-on Feynman Diagrams

    NASA Astrophysics Data System (ADS)

    Kontokostas, George; Kalkanis, George

    2013-04-01

    Feynman diagrams are introduced in many physics textbooks, such as those by Alonso and Finn 1 and Serway,2 and their use in physics education has been discussed by various authors.3-5 They have an appealing simplicity and can give insight into events in the microworld. Yet students often do not understand their significance and often cannot combine the basic units of interaction—points where the world lines of two fermions and one boson meet—to construct diagrams for observed processes.

  16. On the phase diagram of the extended Hubbard model with intersite density-density interactions in the atomic limit

    NASA Astrophysics Data System (ADS)

    Kapcia, Konrad Jerzy; Robaszkiewicz, Stanisław

    2016-11-01

    The charge ordering is a phenomenon associated with inhomogeneous distribution of electron density occurring mostly in strongly correlated materials such as transition metal oxides or organic conductors. The extended Hubbard model (EHM) is one of the simplest model for description of this phenomenon. The full phase diagram of the EHM with intersite density-density interactions W1 and W2 (nearest- and next-nearest-neighbour, respectively) in the atomic limit as a function of the chemical potential has been derived in the variational approach, which treats the on-site interaction exactly and the intersite interactions within mean-field approximation. The results for arbitrary values of model parameters (in the two-sublattice assumption) reveal that the diagram has very complex structure including various (multi-)critical points. A variety of the transitions between different phases, in particular with long-range charge-order, has been found to occur on the diagram. The results presented are rigorous ones in the high-dimension limit for any W1 and W2 ≤ 0.

  17. Teaching Electron--Positron--Photon Interactions with Hands-on Feynman Diagrams

    ERIC Educational Resources Information Center

    Kontokostas, George; Kalkanis, George

    2013-01-01

    Feynman diagrams are introduced in many physics textbooks, such as those by Alonso and Finn and Serway, and their use in physics education has been discussed by various authors. They have an appealing simplicity and can give insight into events in the microworld. Yet students often do not understand their significance and often cannot combine the…

  18. How Different Variants of Orbit Diagrams Influence Student Explanations of the Seasons

    ERIC Educational Resources Information Center

    Lee, Victor R.

    2010-01-01

    The cause of the seasons is often associated with a very particular alternative conception: That the earth's orbit around the sun is highly elongated, and the differences in distance result in variations in temperature. It has been suggested that the standard diagrams used to depict the earth's orbit may be in some way responsible for the initial…

  19. Influence of thermophysical properties of working fluid on the design of cryogenic turboexpanders using nsds diagram

    NASA Astrophysics Data System (ADS)

    Sam, Ashish A.; Ghosh, Parthasarathi

    2015-12-01

    Cryogenic turboexpanders are an essential part of liquefaction and refrigeration plants. The thermodynamic efficiency of these plants depends upon the efficiency of the turboexpander, which is the main cold generating component of these plants, and therefore, they should be designed for high thermodynamic efficiencies. Balje's [1] nsdschart, which is a contour of isentropic efficiencies plotted against specific speed and specific diameter, is commonly used for the preliminary design of cryogenic turboexpanders. But, these charts were developed based on calculations for a specific heat ratio (γ) of 1.4, and studies show that care should be taken while implementing the same for gases which have a higher γ of 1.67. Hence there is a need to investigate the extent of applicability of nsds diagram in designing expansion turbines for higher specific heat ratios. In this paper, Computational Fluid Dynamics (CFD) analysis of cryogenic turboexpanders was carried out using Ansys CFX®. The turboexpanders were designed based on the methodologies prescribed by Kun and Sentz [2] following the nsds diagram of Balje and Hasselgruber's technique for generating blade profile. The computational results of the two cases were analysed to investigate the applicability of Balje's nsds diagram for the design of turboexpanders for refrigeration and liquefaction cycles.

  20. Liquid/liquid metal extraction: Phase diagram topology resulting from molecular interactions between extractant, ion, oil and water

    NASA Astrophysics Data System (ADS)

    Bauer, C.; Bauduin, P.; Dufrêche, J. F.; Zemb, T.; Diat, O.

    2012-11-01

    We consider the class of surfactants called "extractants" since they specifically interact with some cations and are used in liquid-liquid separation processes. We review here features of water-poor reverse micelles in water/oil/ extractant systems as determined by combined structural studies including small angle scattering techniques on absolute scale. Origins of instabilities, liquid-liquid separation as well as emulsification failure are detected. Phase diagrams contain the same multi-phase domains as classical microemulsions, but special unusual features appear due to the high spontaneous curvature directed towards the polar cores of aggregates as well as rigidity of the film made by extracting molecules.

  1. Generating functionals for harmonic expectation values of paths with fixed end points: Feynman diagrams for nonpolynomial interactions.

    PubMed

    Kleinert, H; Pelster, A; Bachmann, M

    1999-09-01

    We introduce a general class of generating functionals for the calculation of quantum-mechanical expectation values of arbitrary functionals of fluctuating paths with fixed end points in configuration or momentum space. The generating functionals are calculated explicitly for the harmonic oscillator with time-dependent frequency, and used to derive a smearing formula for correlation functions of polynomial and nonpolynomial functions of time-dependent positions and momenta. This formula summarizes the effect of quantum fluctuations, and serves to derive generalized Wick rules and Feynman diagrams for perturbation expansions of nonpolynomial interactions.

  2. Gelation and state diagram for a model nanoparticle system with adhesive hard sphere interactions

    NASA Astrophysics Data System (ADS)

    Wagner, Norman; Aaron, Eberle

    2012-02-01

    We provide the first comprehensive state diagram of thermoreversible gelation in a model nanoparticle system from dilute concentrations to the attractive driven glass. We show the temperature dependence of the interparticle potential is related to a surface molecular phase transition of the brush layer using neutron reflectivity (NR) and small-angle neutron scattering (SANS) [1]. We establish the temperature dependence of the interparticle potential using SANS, dynamic light scattering (DLS), and rheology. The potential parameters extracted from SANS suggest that, for this system, gelation is an extension of the Mode Coupling Theory (MCT) attractive driven glass line (ADG) to lower volume fractions and follows the percolation transition. Below the critical concentration, gelation proceeds without competition for phase separation [2]. These results are used to develop a complete state diagram for the sticky hard sphere reference system. [4pt] [1] A.P.R. Eberle, N.J. Wagner, B. Akgun, S.K. Satija, Langmuir 26 3003 (2010).[0pt] [2] A.P.R. Eberle, N.J. Wagner, R. Castaneda-Priego, Phys. Rev. Let. 105704 (2011).

  3. Influence of the antenna diagram on a stellar interferometer that is suffering from telescope-pointing errors.

    PubMed

    Longueteau, Emmanuel; Delage, Laurent; Reynaud, François

    2002-10-01

    We report our experimental investigations of the influence of differential telescope-pointing errors on data corruption in an optical stellar interferometer. This effect was investigated theoretically as a function of the telescope antenna diagram, which depends on the aperture diameter. Using a laboratory breadboard consisting of a three-telescope array, we carried out the experiments with various aperture diameters and complex objects. The results matched the simulation and demonstrate that, when there is no error in pointing, a large aperture size induces correctible error but that, with a pointing error, data corruption becomes critical. In both cases, the larger the apertures, the more corrupt the data.

  4. Influence of trapping potentials on the phase diagram of bosonic atoms in optical lattices

    SciTech Connect

    Giampaolo, S.M.; Illuminati, F.; Mazzarella, G.; De Siena, S.

    2004-12-01

    We study the effect of external trapping potentials on the phase diagram of bosonic atoms in optical lattices. We introduce a generalized Bose-Hubbard Hamiltonian that includes the structure of the energy levels of the trapping potential, and show that these levels are in general populated both at finite and zero temperature. We characterize the properties of the superfluid transition for this situation and compare them with those of the standard Bose-Hubbard description. We briefly discuss similar behaviors for fermionic systems.

  5. Flow Effects on the Flammability Diagrams of Solid Fuels: Microgravity Influence on Ignition Delay

    NASA Technical Reports Server (NTRS)

    Cordova, J. L.; Walther, D. C.; Fernandez-Pello, A. C.; Steinhaus, T.; Torero, J. L.; Quintere, J. G.; Ross, H. D.

    1999-01-01

    The possibility of an accidental fire in space-based facilities is a primary concern of space exploration programs. Spacecraft environments generally present low velocity air currents produced by ventilation and heating systems (of the order of 0.1 m/s), and fluctuating oxygen concentrations around that of air due to CO2 removal systems. Recent experiments of flame spread in microgravity show the spread rate to be faster and the limiting oxygen concentration lower than in normal-gravity. To date, there is not a material flammability-testing protocol that specifically addresses issues related to microgravity conditions. The present project (FIST) aims to establish a testing methodology that is suitable for the specific conditions of reduced gravity. The concepts underlying the operation of the LIFT apparatus, ASTM-E 1321-93, have been used to develop the Forced-flow Ignition and flame-Spread Test (FIST). As in the LIFT, the FIST is used to obtain the flammability diagrams of the material, i.e., graphs of ignition delay time and flame spread rate as a function of the externally applied radiant flux, but under forced flow rather than natural convection conditions, and for different oxygen concentrations. Although the flammability diagrams are similar, the flammability properties obtained with the FIST are found to depend on the flow characteristics. A research program is currently underway with the purpose of implementing the FIST as a protocol to characterize the flammability performance of solid materials to be used in microgravity facilities. To this point, tests have been performed with the FIST apparatus in both normal-gravity and microgravity conditions to determine the effects of oxidizer flow characteristics on the flammability diagrams of polymethylmethacrylate (PMMA) fuel samples. The experiments are conducted at reduced gravity in a KC- 135 aircraft following a parabolic flight trajectory that provides up to 25 seconds of low gravity. The objective of the

  6. MIDAS, prototype Multivariate Interactive Digital Analysis System, phase 1. Volume 3: Wiring diagrams

    NASA Technical Reports Server (NTRS)

    Kriegler, F. J.; Christenson, D.; Gordon, M.; Kistler, R.; Lampert, S.; Marshall, R.; Mclaughlin, R.

    1974-01-01

    The Midas System is a third-generation, fast, multispectral recognition system able to keep pace with the large quantity and high rates of data acquisition from present and projected sensors. A principal objective of the MIDAS Program is to provide a system well interfaced with the human operator and thus to obtain large overall reductions in turn-around time and significant gains in throughput. The hardware and software generated in Phase I of the overall program are described. The system contains a mini-computer to control the various high-speed processing elements in the data path and a classifier which implements an all-digital prototype multivariate-Gaussian maximum likelihood decision algorithm operating at 2 x 100,000 pixels/sec. Sufficient hardware was developed to perform signature extraction from computer-compatible tapes, compute classifier coefficients, control the classifier operation, and diagnose operation. The MIDAS construction and wiring diagrams are given.

  7. Influence of Die and Punch Profile Radii on Deep Drawing Force and Punch Load- Displacement Diagram

    NASA Astrophysics Data System (ADS)

    Mansourinejad, M.; Mirzakhani, B.; Pishbin, H.; Amadeh, A.; Farshchian, B.

    2011-01-01

    In this study, circumstances of formation and development of different zones of cup during the deep drawing process is predicted using geometrical relationships between punch and some process variables. Also, relationships between bending angle, die and punch profile radii, strain in flange and die profile regions are obtained at a given punch travel. In addition, deformation force components are calculated and based on the obtained relationships punch force-displacement diagrams for various punch and die profile radii are plotted. The effects of punch and die profile radii on these diagrams are then discussed. According to the proposed analysis, the effects of die and punch profile radii on deep drawing force are compared with each other. It is concluded that the die profile radius affects not only bending and unbending forces but also the actual drawing ratio while the punch profile radius has only an insignificant effect on actual drawing ratio. Also, effects of die and punch profile radii on punch stroke at maximum load are the same.

  8. Use of an influence diagram and fuzzy probability for evaluating accident management in a boiling water reactor

    SciTech Connect

    Yu, D.; Kastenberg, W.E.; Okrent, D. . Mechanical, Aerospace, and Nuclear Engineering Dept.)

    1994-06-01

    A new approach is presented for evaluating the uncertainties inherent in severe accident management strategies. At first, this analysis considers accident management as a decision problem (i.e., applying a strategy compared with do nothing) and uses an influence diagram. To evaluate imprecise node probabilities in the influence diagram, the analysis introduces the concept of a fuzzy probability. When fuzzy logic is applied, fuzzy probabilities are easily propagated to obtain results. In addition, the results obtained provide not only information similar to the classical approach, which uses point-estimate values, but also additional information regarding the impact of using imprecise input data. As an illustrative example, the proposed methodology is applied to the evaluation of the drywell flooding strategy for a long-term station blackout sequence at the Peach Bottom nuclear power plant. The results show that the drywell flooding strategy is beneficial for preventing reactor vessel breach. It is also effective for reducing the probability of containment failure for both liner melt-through and late overpressurization. Even though uncertainty exists in the results, flooding is preferred to do nothing when evaluated in terms of two risk measures: early and late fatalities.

  9. Investigation of the distinction between van der Waals interaction and chemical bonding based on the PAEM-MO diagram.

    PubMed

    Zhao, Dong-Xia; Yang, Zhong-Zhi

    2014-05-15

    In recent years, the basic problem of understanding chemical bonding, nonbonded, and/or van der Waals interactions has been intensively debated in terms of various theoretical methods. We propose and construct the potential acting on one electron in a molecule-molecular orbital (PAEM-MO) diagram, which draws the PAEM inserted the MO energy levels with their major atomic orbital components. PAEM-MO diagram is able to show clear distinction of chemical bonding from nonbonded and/or vdW interactions. The rule for this is as follows. Along the line connecting two atoms in a molecule or a complex, the existence of chemical bonding between these two atoms needs to satisfy two conditions: (a) a critical point of PAEM exists and (b) PAEM barrier between the two atoms is lower in energy than the occupied major valence-shell bonding MO which contains in-phase atomic components (positive overlap) of the two considered atoms. In contrast to the chemical bonding, for a nonbonded interaction or van der Waals interaction between two atoms, both conditions (a) and (b) do not be satisfied at the same time. This is demonstrated and discussed by various typical cases, particularly those related to helium atom and H-H bonding in phenanthrene. There are helium bonds in HHeF and HeBeO molecules, whereas no H-H bonding in phenanthrene. The validity and limitation for this rule is demonstrated through the investigations of the curves of the PAEM barrier top and MO energies versus the internuclear distances for He2 , H2 , and He2 (+) systems. PMID:24615750

  10. Particles, Feynman Diagrams and All That

    ERIC Educational Resources Information Center

    Daniel, Michael

    2006-01-01

    Quantum fields are introduced in order to give students an accurate qualitative understanding of the origin of Feynman diagrams as representations of particle interactions. Elementary diagrams are combined to produce diagrams representing the main features of the Standard Model.

  11. Ultracold bosons with cavity-mediated long-range interactions: A local mean-field analysis of the phase diagram

    NASA Astrophysics Data System (ADS)

    Niederle, Astrid E.; Morigi, Giovanna; Rieger, Heiko

    2016-09-01

    Ultracold bosonic atoms in optical lattices self-organize into a variety of structural and quantum phases when placed into a single-mode cavity and pumped by a laser. Cavity optomechanical effects induce an atom density modulation at the cavity-mode wavelength that competes with the optical lattice arrangement. Simultaneously short-range interactions via particle hopping promote superfluid order such that a variety of structural and quantum coherent phases can occur. We analyze the emerging phase diagram in two dimensions by means of an extended Bose-Hubbard model using a local mean-field approach combined with a superfluid cluster analysis. For commensurate ratios of the cavity and external lattice wavelengths, the Mott insulator-superfluid transition is modified by the appearance of charge density wave and supersolid phases, at which the atomic density supports the buildup of a cavity field. For incommensurate ratios, the optomechanical forces induce the formation of Bose-glass and superglass phases, namely, nonsuperfluid and superfluid phases, respectively, displaying quasiperiodic density modulations, which in addition can exhibit structural and superfluid stripe formation. The onset of such structures is constrained by the on-site interaction and is favorable at fractional densities. Experimental observables are identified and discussed.

  12. The Influence of the Diameter Ratio on the Characteristics Diagram of the Axial Compressor

    NASA Technical Reports Server (NTRS)

    Eckert, B.; Pflueger, F.; Weinig, F.

    1948-01-01

    With the further development of axial blowers into highly loaded flow machines, the influence of the diameter ratio upon air output and efficiency gains in significance. Clarification of this matter is important for single-stage axial compressors, and is of still greater importance for multistage ones, and particularly for aircraft power plants. Tests with a single-stage axial blower gave a decrease in the attainable maximum pressure coefficient and optimum efficiency as the diameter ratio increased. The decrease must be ascribed chiefly to the guide surface of the hub and housing between the blades increasing with the diameter ratio.

  13. Engineering holographic phase diagrams

    NASA Astrophysics Data System (ADS)

    Chen, Jiunn-Wei; Dai, Shou-Huang; Maity, Debaprasad; Zhang, Yun-Long

    2016-10-01

    By introducing interacting scalar fields, we tried to engineer physically motivated holographic phase diagrams which may be interesting in the context of various known condensed matter systems. We introduce an additional scalar field in the bulk which provides a tunable parameter in the boundary theory. By exploiting the way the tuning parameter changes the effective masses of the bulk interacting scalar fields, desired phase diagrams can be engineered for the boundary order parameters dual to those scalar fields. We give a few examples of generating phase diagrams with phase boundaries which are strikingly similar to the known quantum phases at low temperature such as the superconducting phases. However, the important difference is that all the phases we have discussed are characterized by neutral order parameters. At the end, we discuss if there exists any emerging scaling symmetry associated with a quantum critical point hidden under the dome in this phase diagram.

  14. Influence of Computer-Assisted Roundhouse Diagrams on High School 9th Grade Students' Understanding the Subjects of "Force and Motion"

    ERIC Educational Resources Information Center

    Kocakaya, F.; Gönen, S.

    2014-01-01

    Main aim of this study is to examine the influence of computer-assisted roundhouse diagrams on high school 9th grade students' academic achievements in the subjects of "Force and Motion". The study was carried out in a public high school in Diyarbakir the province in the Southeast of Turkey. In the study, the…

  15. Phase diagrams of Wyoming Na-montmorillonite clay. Influence of particle anisotropy.

    PubMed

    Michot, Laurent J; Bihannic, Isabelle; Porsch, Katharina; Maddi, Solange; Baravian, Christophe; Mougel, Julien; Levitz, Pierre

    2004-12-01

    Natural Na-Wyoming montmorillonite was size fractionated by successive centrifugation. Polydisperse particles with average sizes of 400, 290, and 75 nm were then obtained. As the structural charge of the particles belonging to three fractions (determined by cationic exchange capacity measurements) is the same, such a procedure allows studying the effect of particle anisotropy on the colloidal phase behavior of swelling clay particles. Osmotic stress experiments were carried out at different ionic strengths. The osmotic pressure curves display a plateau whose beginning systematically coincides with the sol/gel transition determined by oscillatory stress measurements. The concentration corresponding to the sol/gel transition increases linearly with particle anisotropy, which shows that the sol/gel transition is not directly related to an isotropic/nematic transition of individual clay particles. Indeed, a reverse evolution should be observed for an I/N transition involving the individual clay particles. Still, when observed between crossed polarizer and analyzer, the gel samples exhibit permanent birefringent textures, whereas in the "sol" region, transient birefringence is observed when the samples are sheared. This suggests that interacting clay particles are amenable to generate, at rest and/or under shear, large anisotropic particle associations. PMID:15568830

  16. The Hubble diagram for a system within dark energy: influence of some relevant quantities

    NASA Astrophysics Data System (ADS)

    Saarinen, J.; Teerikorpi, P.

    2014-08-01

    Aims: We study the influence of relevant quantities, including the density of dark energy (DE), to the predicted Hubble outflow around a system of galaxies. In particular, we are interested in the difference between two models: 1) the standard ΛCDM model, with the everywhere constant DE density, and 2) the "Swiss cheese model", where the Universe is as old as the standard model and the DE density is zero on short scales, including the environment of the system. Methods: We calculated the current predicted outflow patterns of dwarf galaxies around the Local Group-like system, using different values for the mass of the group, the local DE density, and the time of ejection of the dwarf galaxies, which are treated as test particles. These results are compared with the observed Hubble flow around the Local Group. Results: The predicted distance-velocity relations around galaxy groups are not very sensitive indicators of the DE density, owing to the observational scatter and the uncertainties caused by the mass used for the group and a range in the ejection times. In general, the Local Group outflow data agree with the local DE density being equal to the global one, if the Local Group mass is about 4 × 1012 M⊙; a lower mass ≲ 2 × 1012 M⊙ could suggest a zero local DE density. The dependence of the inferred DE density on the mass is a handicap in this and other common dynamical methods. This emphasizes the need to use different approaches together, for constraining the local DE density.

  17. Effect of monomer-monomer interactions on the phase diagrams of the S = 1/2 distorted diamond type quantum spin chain

    NASA Astrophysics Data System (ADS)

    Okamoto, Kiyomi; Tonegawa, Takashi; Sakai, Tôru

    2016-02-01

    By use of mainly the exact diagonalization and the level spectroscopy method, we investigate the ground-state phase diagrams of the S = 1/2 distorted diamond type quantum spin chain with the monomer-monomer interactions and/or ferromagnetic interactions for the zero magnetic field case, as well as the M = Ms/3 case and the M = (2/3)Ms case, where M is the total magnetization and Ms is the saturation magnetization. The magnetization plateau at M = Ms/3 vanishes in the region where the ferromagnetic interaction is rather strong. The monomer-monomer interaction remarkably stabilizes the magnetization plateau at M = (2/3)Ms.

  18. Thermodynamic Diagrams

    NASA Astrophysics Data System (ADS)

    Chaston, Scot

    1999-02-01

    Thermodynamic data such as equilibrium constants, standard cell potentials, molar enthalpies of formation, and standard entropies of substances can be a very useful basis for an organized presentation of knowledge in diverse areas of applied chemistry. Thermodynamic data can become particularly useful when incorporated into thermodynamic diagrams that are designed to be easy to recall, to serve as a basis for reconstructing previous knowledge, and to determine whether reactions can occur exergonically or only with the help of an external energy source. Few students in our chemistry-based courses would want to acquire the depth of knowledge or rigor of professional thermodynamicists. But they should nevertheless learn how to make good use of thermodynamic data in their professional occupations that span the chemical, biological, environmental, and medical laboratory fields. This article discusses examples of three thermodynamic diagrams that have been developed for this purpose. They are the thermodynamic energy account (TEA), the total entropy scale, and the thermodynamic scale diagrams. These diagrams help in the teaching and learning of thermodynamics by bringing the imagination into the process of developing a better understanding of abstract thermodynamic functions, and by allowing the reader to keep track of specialist thermodynamic discourses in the literature.

  19. Hubble Diagram

    NASA Astrophysics Data System (ADS)

    Djorgovski, S.; Murdin, P.

    2000-11-01

    Initially introduced as a way to demonstrate the expansion of the universe, and subsequently to determine the expansion rate (the HUBBLE CONSTANT H0), the Hubble diagram is one of the classical cosmological tests. It is a plot of apparent fluxes (usually expressed as magnitudes) of some types of objects at cosmological distances, against their REDSHIFTS. It is used as a tool to measure the glob...

  20. Influence of interstitial Fe to the phase diagram of Fe1+yTe1-xSex single crystals.

    PubMed

    Sun, Yue; Yamada, Tatsuhiro; Pyon, Sunseng; Tamegai, Tsuyoshi

    2016-01-01

    Superconductivity (SC) with the suppression of long-range antiferromagnetic (AFM) order is observed in the parent compounds of both iron-based and cuprate superconductors. The AFM wave vectors are bicollinear (π, 0) in the parent compound FeTe different from the collinear AFM order (π, π) in most iron pnictides. Study of the phase diagram of Fe1+yTe1-xSex is the most direct way to investigate the competition between bicollinear AFM and SC. However, presence of interstitial Fe affects both magnetism and SC of Fe1+yTe1-xSex, which hinders the establishment of the real phase diagram. Here, we report the comparison of doping-temperature (x-T) phase diagrams for Fe1+yTe1-xSex (0 ≤ x ≤ 0.43) single crystals before and after removing interstitial Fe. Without interstitial Fe, the AFM state survives only for x < 0.05, and bulk SC emerges from x = 0.05, and does not coexist with the AFM state. The previously reported spin glass state, and the coexistence of AFM and SC may be originated from the effect of the interstitial Fe. The phase diagram of Fe1+yTe1-xSex is found to be similar to the case of the "1111" system such as LaFeAsO1-xFx, and is different from that of the "122" system. PMID:27577047

  1. Spin-lattice interactions as revealed by the pressure-temperature phase diagram of Co[N(CN)2 ]2

    NASA Astrophysics Data System (ADS)

    Musfeldt, Janice; Brinzari, T. V.; O'Neal, K. R.; Chen, P.; Schleuter, J. A.; Manson, J. L.; Litvinchuk, A. P.; Liu, Z.

    2015-03-01

    We combined diamond anvil cell techniques, synchrotron-based infrared and Raman spectroscopies, and complementary lattice dynamics calculations to investigate spin-lattice coupling and the magnetic crossover mechanism in the molecule-based quantum magnet Co[N(CN)2]2. These findings along with prior magnetic properties work were brought together to create a pressure-temperature phase diagram in which the second-order structural boundaries converge on key areas of activity involving the spin state, exposing how the pressure-induced local lattice distortions trigger the ferromagnetic to antiferromagnetic crossover transition. Similar triggering events may take place in other materials. We thank the NSF and PRF for support of this work.

  2. Scattering equations and Feynman diagrams

    NASA Astrophysics Data System (ADS)

    Baadsgaard, Christian; Bjerrum-Bohr, N. E. J.; Bourjaily, Jacob L.; Damgaard, Poul H.

    2015-09-01

    We show a direct matching between individual Feynman diagrams and integration measures in the scattering equation formalism of Cachazo, He and Yuan. The connection is most easily explained in terms of triangular graphs associated with planar Feynman diagrams in φ 3-theory. We also discuss the generalization to general scalar field theories with φ p interactions, corresponding to polygonal graphs involving vertices of order p. Finally, we describe how the same graph-theoretic language can be used to provide the precise link between individual Feynman diagrams and string theory integrands.

  3. Phase diagram of the alternating-spin Heisenberg chain with extra isotropic three-body exchange interactions

    NASA Astrophysics Data System (ADS)

    Ivanov, Nedko B.; Ummethum, Jörg; Schnack, Jürgen

    2014-10-01

    For the time being isotropic three-body exchange interactions are scarcely explored and mostly used as a tool for constructing various exactly solvable one-dimensional models, although, generally speaking, such competing terms in generic Heisenberg spin systems can be expected to support specific quantum effects and phases. The Heisenberg chain constructed from alternating S = 1 and σ = 1/2 site spins defines a realistic prototype model admitting extra three-body exchange terms. Based on numerical density-matrix renormalization group (DMRG) and exact diagonalization (ED) calculations, we demonstrate that the additional isotropic three-body terms stabilize a variety of partially-polarized states as well as two specific non-magnetic states including a critical spin-liquid phase controlled by two Gaussinal conformal theories as well as a critical nematic-like phase characterized by dominant quadrupolar S-spin fluctuations. Most of the established effects are related to some specific features of the three-body interaction such as the promotion of local collinear spin configurations and the enhanced tendency towards nearest-neighbor clustering of the spins. It may be expected that most of the predicted effects of the isotropic three-body interaction persist in higher space dimensions.

  4. Ion mixing and phase diagrams

    NASA Astrophysics Data System (ADS)

    Lau, S. S.; Liu, B. X.; Nicolet, M.-A.

    1983-05-01

    Interactions induced by ion irradiation are generally considered to be non-equilibrium processes, whereas phase diagrams are determined by phase equilibria. These two entities are seemingly unrelated. However, if one assumes that quasi-equilibrium conditions prevail after the prompt events, subsequent reactions are driven toward equilibrium by thermodynamical forces. Under this assumption, ion-induced reactions are related to equilibrium and therefore to phase diagrams. This relationship can be seen in the similarity that exists in thin films between reactions induced by ion irradiation and reactions induced by thermal annealing. In the latter case, phase diagrams have been used to predict the phase sequence of stable compound formation, notably so in cases of silicide formation. Ion-induced mixing not only can lead to stable compound formation, but also to metastable alloy formation. In some metal-metal systems, terminal solubilities can be greatly extended by ion mixing. In other cases, where the two constituents of the system have different crystal structures, extension of terminal solubility from both sides of the phase diagram eventually becomes structurally incompatible and a glassy (amorphous) mixture can form. The composition range where this bifurcation is likely to occur is in the two-phase regions of the phase diagram. These concepts are potentially useful guides in selecting metal pairs that from metallic glasses by ion mixing. In this report, phenomenological correlation between stable (and metastable) phase formation and phase diagram is discussed in terms of recent experimental data.

  5. Influence of Radioactivity on Surface Interaction Forces

    SciTech Connect

    Walker, Mark E; McFarlane, Joanna; Glasgow, David C; Chung, Eunhyea; Taboada Serrano, Patricia L; Yiacoumi, Sotira; Tsouris, Costas

    2010-01-01

    Although some differences have been observed, the transport behavior of radioactive aerosol particles has often been assumed to be analogous to the behavior of nonradioactive aerosols in dispersion models. However, radioactive particles can become electrostatically charged as a result of the decay process. Theories have been proposed to describe this self-charging phenomenon, which may have a significant effect on how these particles interact with one another and with charged surfaces in the environment. In this study, atomic force microscopy (AFM) was employed to quantify surface forces between a particle and a planar surface and to compare measurements with and without the involvement of radioactivity. The main objective of this work is to assess directly the effects of radioactivity on the surface interactions of radioactive aerosols via the measurement of the adhesion force. The adhesion force between a silicon nitride AFM tip and an activated gold substrate was measured so that any possible effects due to radioactivity could be observed. The adhesion force between the tip and the gold surface increased significantly when the gold substrate (25 mm{sup 2} surface area) was activated to a level of approximately 0.6 mCi. The results of this investigation will prompt further work into the effects of radioactivity in particle-surface interactions.

  6. Influence of radioactivity on surface interaction forces.

    PubMed

    Walker, M E; McFarlane, J; Glasgow, D C; Chung, E; Taboada-Serrano, P; Yiacoumi, S; Tsouris, C

    2010-10-15

    Although some differences have been observed, the transport behavior of radioactive aerosol particles has often been assumed to be analogous to the behavior of nonradioactive aerosols in dispersion models. However, radioactive particles can become electrostatically charged as a result of the decay process. Theories have been proposed to describe this self-charging phenomenon, which may have a significant effect on how these particles interact with one another and with charged surfaces in the environment. In this study, atomic force microscopy (AFM) was employed to quantify surface forces between a particle and a planar surface and to compare measurements with and without the involvement of radioactivity. The main objective of this work is to assess directly the effects of radioactivity on the surface interactions of radioactive aerosols via the measurement of the adhesion force. The adhesion force between a silicon nitride AFM tip and an activated gold substrate was measured so that any possible effects due to radioactivity could be observed. The adhesion force between the tip and the gold surface increased significantly when the gold substrate (25 mm(2) surface area) was activated to a level of approximately 0.6 mCi. The results of this investigation will prompt further work into the effects of radioactivity in particle-surface interactions.

  7. A Regime Diagram for Subduction

    NASA Astrophysics Data System (ADS)

    Stegman, D. R.; Farrington, R.; Capitanio, F. A.; Schellart, W. P.

    2009-12-01

    Regime diagrams and associated scaling relations have profoundly influenced our understanding of planetary dynamics. Previous regime diagrams characterized the regimes of stagnant-lid, small viscosity contrast, transitional, and no-convection for temperature-dependent (Moresi and Solomatov, 1995), and non-linear power law rheologies (Solomatov and Moresi, 1997) as well as stagnant-lid, sluggish-lid, and mobile-lid regimes once the finite strength of rock was considered (Moresi and Solomatov, 1998). Scalings derived from such models have been the cornerstone for parameterized models of thermal evolution of rocky planets and icy moons for the past decade. While such a theory can predict the tectonic state of a planetary body, it is still rather incomplete in regards to predicting tectonics. For example, the mobile-lid regime is unspecific as to how continuous lithospheric recycling should occur on a terrestrial planet. Towards this goal, Gerya et al., (2008) advanced a new regime diagram aiming to characterize when subduction would manifest itself as a one-sided or two-sided downwelling and either symmetric or asymmetric. Here, we present a regime diagram for the case of a single-sided, asymmetric type of subduction (most Earth-like type). Using a 3-D numerical model of a free subduction, we describe a total of 5 different styles of subduction that can possibly occur. Each style is distinguished by its upper mantle slab morphology resulting from the sinking kinematics. We provide movies to illustrate the different styles and their progressive time-evolution. In each regime, subduction is accommodated by a combination of plate advance and slab rollback, with associated motions of forward plate velocity and trench retreat, respectively. We demonstrate that the preferred subduction mode depends upon two essential controlling factors: 1) buoyancy of the downgoing plate and 2) strength of plate in resisting bending at the hinge. We propose that a variety of subduction

  8. The Influence of Proxemic Variables on Dyadic Interaction Between Peers.

    ERIC Educational Resources Information Center

    Weiss, Michael; Keys, Christopher

    This study addresses three issues: (1) the influence of proxemic variables (distance, furniture presence) on dyadic interaction; (2) the consistency between measures of self-disclosure; and (3) the applicability of reciprocity and distance-equilibrium views of dyadic interaction. Dyads of male college students were randomly assigned to one of four…

  9. Caution: Venn Diagrams Ahead!

    ERIC Educational Resources Information Center

    Kimmins, Dovie L.; Winters, J. Jeremy

    2015-01-01

    Two perspectives of the term "Venn diagram" reflect the typical differences in the uses of Venn diagrams in the subject areas of mathematics and language arts. These differences are subtle; nevertheless, they can potentially be confusing. In language arts, the circles in a Venn diagram typically represent things that can be compared and…

  10. Lipid-alamethicin interactions influence alamethicin orientation.

    PubMed

    Huang, H W; Wu, Y

    1991-11-01

    dipole-electric field interactions. We speculate that the phase-transitionlike behavior is a manifestation of membrane-mediated intermolecular interactions between peptide molecules. PMID:19431805

  11. Lipid-alamethicin interactions influence alamethicin orientation

    PubMed Central

    Huang, Huey W.; Wu, Yili

    1991-01-01

    -electric field interactions. We speculate that the phase-transitionlike behavior is a manifestation of membrane-mediated intermolecular interactions between peptide molecules. PMID:19431805

  12. Phase Equilibria Diagrams Database

    National Institute of Standards and Technology Data Gateway

    SRD 31 NIST/ACerS Phase Equilibria Diagrams Database (PC database for purchase)   The Phase Equilibria Diagrams Database contains commentaries and more than 21,000 diagrams for non-organic systems, including those published in all 21 hard-copy volumes produced as part of the ACerS-NIST Phase Equilibria Diagrams Program (formerly titled Phase Diagrams for Ceramists): Volumes I through XIV (blue books); Annuals 91, 92, 93; High Tc Superconductors I & II; Zirconium & Zirconia Systems; and Electronic Ceramics I. Materials covered include oxides as well as non-oxide systems such as chalcogenides and pnictides, phosphates, salt systems, and mixed systems of these classes.

  13. The influence of nanostructured materials on biointerfacial interactions.

    PubMed

    Koegler, Peter; Clayton, Andrew; Thissen, Helmut; Santos, Gil Nonato C; Kingshott, Peter

    2012-12-01

    Control over biointerfacial interactions in vitro and in vivo is the key to many biomedical applications: from cell culture and diagnostic tools to drug delivery, biomaterials and regenerative medicine. The increasing use of nanostructured materials is placing a greater demand on improving our understanding of how these new materials influence biointerfacial interactions, including protein adsorption and subsequent cellular responses. A range of nanoscale material properties influence these interactions, and material toxicity. The ability to manipulate both material nanochemistry and nanotopography remains challenging in its own right, however, a more in-depth knowledge of the subsequent biological responses to these new materials must occur simultaneously if they are ever to be affective in the clinic. We highlight some of the key technologies used for fabrication of nanostructured materials, examine how nanostructured materials influence the behavior of proteins and cells at surfaces and provide details of important analytical techniques used in this context.

  14. Phase diagrams of a ferromagnetic amorphous bilayer system

    NASA Astrophysics Data System (ADS)

    Bengrine, M.; Benyoussef, A.; El Kenz, A.; Loulidi, M.; Mhirech, F.

    1998-03-01

    Using the effective-field theory, we study phase diagrams of a ferromagnetic amorphous bilayer system, consisting of two monolayers (A and B) with different spins ( SA= {1}/{2} and SB= {1}/{2}, 1) and different interaction constants coupled together with an interlayer coupling. The effects of amorphization in the monolayer B and in the interlayer coupling are investigated. The influence of the crystal-field interaction D, in the case SA= {1}/{2} and SB=1, is also studied. A number of interesting phenomena are obtained such as the dependence of the tricritical behavior on amorphization. Other phenomena have been given in a variety of phase diagrams. The temperature dependence of the total magnetization is also examined.

  15. Gravity wave transmission diagram

    NASA Astrophysics Data System (ADS)

    Tomikawa, Yoshihiro

    2016-07-01

    A possibility of gravity wave propagation from a source region to the airglow layer around the mesopause has been discussed based on the gravity wave blocking diagram taking into account the critical level filtering alone. This paper proposes a new gravity wave transmission diagram in which both the critical level filtering and turning level reflection of gravity waves are considered. It shows a significantly different distribution of gravity wave transmissivity from the blocking diagram.

  16. Reading fitness landscape diagrams through HSAB concepts

    NASA Astrophysics Data System (ADS)

    Vigneresse, Jean-Louis

    2014-10-01

    Fitness landscapes are conceived as range of mountains, with local peaks and valleys. In terms of potential, such topographic variations indicate places of local instability or stability. The chemical potential, or electronegativity, its value changed of sign, carries similar information. In addition to chemical descriptors defined through hard-soft acid-base (HSAB) concepts and computed through density functional theory (DFT), the principles that rule chemical reactions allow the design of such landscape diagrams. The simplest diagram uses electrophilicity and hardness as coordinates. It allows examining the influence of maximum hardness or minimum electrophilicity principles. A third dimension is introduced within such a diagram by mapping the topography of electronegativity, polarizability or charge exchange. Introducing charge exchange during chemical reactions, or mapping a third parameter (f.i. polarizability) reinforces the information carried by a simple binary diagram. Examples of such diagrams are provided, using data from Earth Sciences, simple oxides or ligands.

  17. Hertzsprung-Russell Diagram

    NASA Astrophysics Data System (ADS)

    Chiosi, C.; Murdin, P.

    2000-11-01

    The Hertzsprung-Russell diagram (HR-diagram), pioneered independently by EJNAR HERTZSPRUNG and HENRY NORRIS RUSSELL, is a plot of the star luminosity versus the surface temperature. It stems from the basic relation for an object emitting thermal radiation as a black body: ...

  18. Influence of vane sweep on rotor-stator interaction noise

    NASA Astrophysics Data System (ADS)

    Envia, Edmane; Kerschen, Edward J.

    1990-12-01

    The influence of vane sweep in rotor-stator interaction noise is investigated. In an analytical approach, the interaction of a convected gust representing the rotor viscous wake, with a cascade of cascade of finite span swept airfoils, representing the stator, is analyzed. The analysis is based on the solution of the exact linearized equations of motion. High frequency convected gusts for which noise generation is concentrated near the leading edge of airfoils is considered. In a preliminary study, the problem of an isolated finite span swept airfoil interacting with a convected gust is analyzed. Results indicate that sweep can substantially reduce the farfield noise levels for a single airfoil. Using the single airfoil model, an approximate solution to the problem of noise radiation from a cascade of finite span swept airfoils interacting with a convected gust is derived. A parametric study of noise generated by gust cascade interaction is carried out to assess the effectiveness of vane sweep in reducing rotor-stator interaction noise. The results show that sweep is beneficial in reducing noise levels. Rotor wake twist or circumferential lean substantially influences the effectiveness of vane sweep. The orientation of vane sweep must be chosen to enhance the natural phase lag caused by wake lean, in which case rather small sweep angles substantially reduce the noise levels.

  19. Influence of vane sweep on rotor-stator interaction noise

    NASA Technical Reports Server (NTRS)

    Envia, Edmane; Kerschen, Edward J.

    1990-01-01

    The influence of vane sweep in rotor-stator interaction noise is investigated. In an analytical approach, the interaction of a convected gust representing the rotor viscous wake, with a cascade of cascade of finite span swept airfoils, representing the stator, is analyzed. The analysis is based on the solution of the exact linearized equations of motion. High frequency convected gusts for which noise generation is concentrated near the leading edge of airfoils is considered. In a preliminary study, the problem of an isolated finite span swept airfoil interacting with a convected gust is analyzed. Results indicate that sweep can substantially reduce the farfield noise levels for a single airfoil. Using the single airfoil model, an approximate solution to the problem of noise radiation from a cascade of finite span swept airfoils interacting with a convected gust is derived. A parametric study of noise generated by gust cascade interaction is carried out to assess the effectiveness of vane sweep in reducing rotor-stator interaction noise. The results show that sweep is beneficial in reducing noise levels. Rotor wake twist or circumferential lean substantially influences the effectiveness of vane sweep. The orientation of vane sweep must be chosen to enhance the natural phase lag caused by wake lean, in which case rather small sweep angles substantially reduce the noise levels.

  20. Massive basketball diagram for a thermal scalar field theory

    NASA Astrophysics Data System (ADS)

    Andersen, Jens O.; Braaten, Eric; Strickland, Michael

    2000-08-01

    The ``basketball diagram'' is a three-loop vacuum diagram for a scalar field theory that cannot be expressed in terms of one-loop diagrams. We calculate this diagram for a massive scalar field at nonzero temperature, reducing it to expressions involving three-dimensional integrals that can be easily evaluated numerically. We use this result to calculate the free energy for a massive scalar field with a φ4 interaction to three-loop order.

  1. Calculation of the pair potential interaction in electric double-layered magnetic fluids: a quantitative analysis of the pH-dependent phase diagram

    NASA Astrophysics Data System (ADS)

    Campos, A. F. C.; Tourinho, F. A.; da Silva, G. J.; Depeyrot, J.

    2005-03-01

    In this work, the phase behavior of an acidic EDL-MF sample based on cobalt ferrite nanoparticles is studied in absence of external magnetic field and constant temperature. An experimental pH-dependent phase diagram of the ferrofluid sample is established and the result shows three phases in different pH ranges: a sol phase in low pH conditions, a gel phase when 3.8 diagram.

  2. Hand gestures and perceived influence in small group interaction.

    PubMed

    Maricchiolo, Fridanna; Livi, Stefano; Bonaiuto, Marino; Gnisci, Augusto

    2011-11-01

    A laboratory study was carried out to establish the relative importance of verbal and gestural behavior, as well as their interaction, for perceived social influence in more or less competitive small groups. Forty women (psychology students) participated in leaderless small group discussions of different sizes (four-member and eight-member): at the end, each member rated the perceived influence in decision-making of every other member. Verbal dominance coding is based on traditional quantitative conversational dominance (number of talk turns). Gestural coding (conversational, ideational, object-adaptor, self-adaptor gestures) is based on classical gesture classifications. Beside a substantial effect of verbal dominance, the main result is that frequency of object-adaptors and conversational (only in large groups) and ideational (in both small and large groups) gestures increases perceived influence scores particularly when the verbal dominance of the speaker is low.

  3. Square Source Type Diagram

    NASA Astrophysics Data System (ADS)

    Aso, N.; Ohta, K.; Ide, S.

    2014-12-01

    Deformation in a small volume of earth interior is expressed by a symmetric moment tensor located on a point source. The tensor contains information of characteristic directions, source amplitude, and source types such as isotropic, double-couple, or compensated-linear-vector-dipole (CLVD). Although we often assume a double couple as the source type of an earthquake, significant non-double-couple component including isotropic component is often reported for induced earthquakes and volcanic earthquakes. For discussions on source types including double-couple and non-double-couple components, it is helpful to display them using some visual diagrams. Since the information of source type has two degrees of freedom, it can be displayed onto a two-dimensional flat plane. Although the diagram developed by Hudson et al. [1989] is popular, the trace corresponding to the mechanism combined by two mechanisms is not always a smooth line. To overcome this problem, Chapman and Leaney [2012] developed a new diagram. This diagram has an advantage that a straight line passing through the center corresponds to the mechanism obtained by a combination of an arbitrary mechanism and a double-couple [Tape and Tape, 2012], but this diagram has some difficulties in use. First, it is slightly difficult to produce the diagram because of its curved shape. Second, it is also difficult to read out the ratios among isotropic, double-couple, and CLVD components, which we want to obtain from the estimated moment tensors, because they do not appear directly on the horizontal or vertical axes. In the present study, we developed another new square diagram that overcomes the difficulties of previous diagrams. This diagram is an orthogonal system of isotropic and deviatoric axes, so it is easy to get the ratios among isotropic, double-couple, and CLVD components. Our diagram has another advantage that the probability density is obtained simply from the area within the diagram if the probability density

  4. The f-spin physics of rare-earth iron pnictides: influence of d-electron antiferromagnetic order on heavy fermion phase diagram

    SciTech Connect

    Zhu, Jian-xin; Dai, Jianhui; Si, Qimiao

    2009-01-01

    Some of the high {Tc} iron pnictides contain rare-earth elements, raising the question of how the existence and tunability of a d-electron antiferromagnetic order influences the heavy fermion behavior of the f-moments. With CeOFeP and CeOFeAs in mind as prototypes, we derive an extended Anderson lattice model appropriate for these quaternary systems. We show that the Kondo screening of the f-moments are efficiently suppressed by the d-electron ordering. We also argue that, inside the d-electron ordered state (as in CeOFeAs), the f-moments provide a rare realization of a quantum frustrated magnet with competing J{sub 1}-J{sub 2}-J{sub 3} interactions in an effective square lattice. Implications ofr the heavy fermion physics in broader contexts are also discussed.

  5. Influence of interstitial Fe to the phase diagram of Fe1+yTe1‑xSex single crystals

    NASA Astrophysics Data System (ADS)

    Sun, Yue; Yamada, Tatsuhiro; Pyon, Sunseng; Tamegai, Tsuyoshi

    2016-08-01

    Superconductivity (SC) with the suppression of long-range antiferromagnetic (AFM) order is observed in the parent compounds of both iron-based and cuprate superconductors. The AFM wave vectors are bicollinear (π, 0) in the parent compound FeTe different from the collinear AFM order (π, π) in most iron pnictides. Study of the phase diagram of Fe1+yTe1‑xSex is the most direct way to investigate the competition between bicollinear AFM and SC. However, presence of interstitial Fe affects both magnetism and SC of Fe1+yTe1‑xSex, which hinders the establishment of the real phase diagram. Here, we report the comparison of doping-temperature (x-T) phase diagrams for Fe1+yTe1‑xSex (0 ≤ x ≤ 0.43) single crystals before and after removing interstitial Fe. Without interstitial Fe, the AFM state survives only for x < 0.05, and bulk SC emerges from x = 0.05, and does not coexist with the AFM state. The previously reported spin glass state, and the coexistence of AFM and SC may be originated from the effect of the interstitial Fe. The phase diagram of Fe1+yTe1‑xSex is found to be similar to the case of the “1111” system such as LaFeAsO1‑xFx, and is different from that of the “122” system.

  6. Influence of interstitial Fe to the phase diagram of Fe1+yTe1−xSex single crystals

    PubMed Central

    Sun, Yue; Yamada, Tatsuhiro; Pyon, Sunseng; Tamegai, Tsuyoshi

    2016-01-01

    Superconductivity (SC) with the suppression of long-range antiferromagnetic (AFM) order is observed in the parent compounds of both iron-based and cuprate superconductors. The AFM wave vectors are bicollinear (π, 0) in the parent compound FeTe different from the collinear AFM order (π, π) in most iron pnictides. Study of the phase diagram of Fe1+yTe1−xSex is the most direct way to investigate the competition between bicollinear AFM and SC. However, presence of interstitial Fe affects both magnetism and SC of Fe1+yTe1−xSex, which hinders the establishment of the real phase diagram. Here, we report the comparison of doping-temperature (x-T) phase diagrams for Fe1+yTe1−xSex (0 ≤ x ≤ 0.43) single crystals before and after removing interstitial Fe. Without interstitial Fe, the AFM state survives only for x < 0.05, and bulk SC emerges from x = 0.05, and does not coexist with the AFM state. The previously reported spin glass state, and the coexistence of AFM and SC may be originated from the effect of the interstitial Fe. The phase diagram of Fe1+yTe1−xSex is found to be similar to the case of the “1111” system such as LaFeAsO1−xFx, and is different from that of the “122” system. PMID:27577047

  7. G×E Interaction Influences Trajectories of Hand Grip Strength

    PubMed Central

    Pedersen, Nancy L.; Rantanen, Taina; Kremen, William S.; Johnson, Wendy; Panizzon, Matthew S.; Christiansen, Lene; Franz, Carol E.; McGue, Matt; Christensen, Kaare; Hamdi, Nayla R.; Krueger, Robert F.; Reynolds, Chandra

    2015-01-01

    Age-related decline in grip strength predicts later life disability, frailty, lower well-being and cognitive change. While grip strength is heritable, genetic influence on change in grip strength has been relatively ignored, with non-shared environmental influence identified as the primary contributor in a single longitudinal study. The extent to which gene-environment interplay, particularly gene-environment interactions, contributes to grip trajectories has yet to be examined. We considered longitudinal grip strength measurements in seven twin studies of aging in the Interplay of Genes and Environment across Multiple Studies consortium. Growth curve parameters were estimated for same-sex pairs, aged 34–99 (N = 10,681). Fisher's test for mixture distribution of within-monozy-gotic twin-pair differences (N = 1724) was performed on growth curve parameters. We observed significant gene-environment interaction on grip strength trajectories. Finally, we compared the variability of within-pair differences of growth curve parameters by APOE haplotypes. Though not statistically significant, the results suggested that APOE ε2ε2/ε2ε3 haplotypes might buffer environmental influences on grip strength trajectories. PMID:26318288

  8. Phase Diagrams of Electric-Fduced Aggregation in Conducting Colloids

    NASA Technical Reports Server (NTRS)

    Khusid, B.; Acrivos, A.

    1999-01-01

    Under the application of a sufficiently strong electric field, a suspension may undergo reversible phase transitions from a homogeneous random arrangement of particles into a variety of ordered aggregation patterns. The surprising fact about electric-field driven phase transitions is that the aggregation patterns, that are observed in very diverse systems of colloids, display a number of common structural features and modes of evolution thereby implying that a universal mechanism may exist to account for these phenomena. It is now generally believed that this mechanism emanates from the presence of the long-range anisotropic interactions between colloidal particles due to their polarization in an applied field. But, in spite of numerous applications of the electric-field-driven phenomena in biotechnology, separation, materials engineering, chemical analysis, etc. our understanding of these phenomena is far from complete. Thus, it is the purpose of the proposed research to develop a theory and then test experimentally, under normal- and low-gravity conditions, the accuracy of the theoretical predictions regarding the effect of the synergism of the interparticle electric and hydrodynamic interactions on the phase diagram of a suspension. The main results from our theoretical studies performed to-date enable one to trace how the variations of the electrical properties of the constituent materials influence the topology of the suspension phase diagram and then, by using an appropriate phase diagram, to evaluate how the electric-field-induced transformations will depend on the frequency and the strength of the applied field.

  9. Biotic-Abiotic Interactions: Factors that Influence Peptide-Graphene Interactions.

    PubMed

    Kim, Steve S; Kuang, Zhifeng; Ngo, Yen H; Farmer, Barry L; Naik, Rajesh R

    2015-09-16

    Understanding the factors that influence the interaction between biomolecules and abiotic surfaces is of utmost interest in biosensing and biomedical research. Through phage display technology, several peptides have been identified as specific binders to abiotic material surfaces, such as gold, graphene, silver, and so forth. Using graphene-peptide as our model abiotic-biotic pair, we investigate the effect of graphene quality, number of layers, and the underlying support substrate effect on graphene-peptide interactions using both experiments and computation. Our results indicate that graphene quality plays a significant role in graphene-peptide interactions. The graphene-biomolecule interaction appears to show no significant dependency on the number of graphene layers or the underlying support substrate. PMID:26305504

  10. Biotic-Abiotic Interactions: Factors that Influence Peptide-Graphene Interactions.

    PubMed

    Kim, Steve S; Kuang, Zhifeng; Ngo, Yen H; Farmer, Barry L; Naik, Rajesh R

    2015-09-16

    Understanding the factors that influence the interaction between biomolecules and abiotic surfaces is of utmost interest in biosensing and biomedical research. Through phage display technology, several peptides have been identified as specific binders to abiotic material surfaces, such as gold, graphene, silver, and so forth. Using graphene-peptide as our model abiotic-biotic pair, we investigate the effect of graphene quality, number of layers, and the underlying support substrate effect on graphene-peptide interactions using both experiments and computation. Our results indicate that graphene quality plays a significant role in graphene-peptide interactions. The graphene-biomolecule interaction appears to show no significant dependency on the number of graphene layers or the underlying support substrate.

  11. Upgrading Diagnostic Diagrams

    NASA Astrophysics Data System (ADS)

    Proxauf, B.; Kimeswenger, S.; Öttl, S.

    2014-04-01

    Diagnostic diagrams of forbidden lines have been a useful tool for observers in astrophysics for many decades now. They are used to obtain information on the basic physical properties of thin gaseous nebulae. Moreover they are also the initial tool to derive thermodynamic properties of the plasma from observations to get ionization correction factors and thus to obtain proper abundances of the nebulae. Some diagnostic diagrams are in wavelengths domains which were difficult to take either due to missing wavelength coverage or low resolution of older spectrographs. Thus they were hardly used in the past. An upgrade of this useful tool is necessary because most of the diagrams were calculated using only the species involved as a single atom gas, although several are affected by well-known fluorescence mechanisms as well. Additionally the atomic data have improved up to the present time. The new diagnostic diagrams are calculated by using large grids of parameter space in the photoionization code CLOUDY. For a given basic parameter the input radiation field is varied to find the solutions with cooling-heating-equilibrium. Empirical numerical functions are fitted to provide formulas usable in e.g. data reduction pipelines. The resulting diagrams differ significantly from those used up to now and will improve the thermodynamic calculations.

  12. Weyl card diagrams

    SciTech Connect

    Jones, Gregory; Wang, John E.

    2005-06-15

    To capture important physical properties of a spacetime we construct a new diagram, the card diagram, which accurately draws generalized Weyl spacetimes in arbitrary dimensions by encoding their global spacetime structure, singularities, horizons, and some aspects of causal structure including null infinity. Card diagrams draw only nontrivial directions providing a clearer picture of the geometric features of spacetimes as compared to Penrose diagrams, and can change continuously as a function of the geometric parameters. One of our main results is to describe how Weyl rods are traversable horizons and the entirety of the spacetime can be mapped out. We review Weyl techniques and as examples we systematically discuss properties of a variety of solutions including Kerr-Newman black holes, black rings, expanding bubbles, and recent spacelike-brane solutions. Families of solutions will share qualitatively similar cards. In addition we show how card diagrams not only capture information about a geometry but also its analytic continuations by providing a geometric picture of analytic continuation. Weyl techniques are generalized to higher dimensional charged solutions and applied to generate perturbations of bubble and S-brane solutions by Israel-Khan rods.

  13. The influence of biological rhythms on host-parasite interactions.

    PubMed

    Martinez-Bakker, Micaela; Helm, Barbara

    2015-06-01

    Biological rhythms, from circadian control of cellular processes to annual cycles in life history, are a main structural element of biology. Biological rhythms are considered adaptive because they enable organisms to partition activities to cope with, and take advantage of, predictable fluctuations in environmental conditions. A flourishing area of immunology is uncovering rhythms in the immune system of animals, including humans. Given the temporal structure of immunity, and rhythms in parasite activity and disease incidence, we propose that the intersection of chronobiology, disease ecology, and evolutionary biology holds the key to understanding host-parasite interactions. Here, we review host-parasite interactions while explicitly considering biological rhythms, and propose that rhythms: influence within-host infection dynamics and transmission between hosts, might account for diel and annual periodicity in host-parasite systems, and can lead to a host-parasite arms race in the temporal domain.

  14. Influence of airfoil thickness on convected gust interaction noise

    NASA Technical Reports Server (NTRS)

    Kerschen, E. J.; Tsai, C. T.

    1989-01-01

    The case of a symmetric airfoil at zero angle of attack is considered in order to determine the influence of airfoil thickness on sound generated by interaction with convected gusts. The analysis is based on a linearization of the Euler equations about the subsonic mean flow past the airfoil. Primary sound generation is found to occur in a local region surrounding the leading edge, with the size of the local region scaling on the gust wavelength. For a parabolic leading edge, moderate leading edge thickness is shown to decrease the noise level in the low Mach number limit.

  15. A pseudo-haptic knot diagram interface

    NASA Astrophysics Data System (ADS)

    Zhang, Hui; Weng, Jianguang; Hanson, Andrew J.

    2011-01-01

    To make progress in understanding knot theory, we will need to interact with the projected representations of mathematical knots which are of course continuous in 3D but significantly interrupted in the projective images. One way to achieve such a goal would be to design an interactive system that allows us to sketch 2D knot diagrams by taking advantage of a collision-sensing controller and explore their underlying smooth structures through a continuous motion. Recent advances of interaction techniques have been made that allow progress to be made in this direction. Pseudo-haptics that simulates haptic effects using pure visual feedback can be used to develop such an interactive system. This paper outlines one such pseudo-haptic knot diagram interface. Our interface derives from the familiar pencil-and-paper process of drawing 2D knot diagrams and provides haptic-like sensations to facilitate the creation and exploration of knot diagrams. A centerpiece of the interaction model simulates a "physically" reactive mouse cursor, which is exploited to resolve the apparent conflict between the continuous structure of the actual smooth knot and the visual discontinuities in the knot diagram representation. Another value in exploiting pseudo-haptics is that an acceleration (or deceleration) of the mouse cursor (or surface locator) can be used to indicate the slope of the curve (or surface) of whom the projective image is being explored. By exploiting these additional visual cues, we proceed to a full-featured extension to a pseudo-haptic 4D visualization system that simulates the continuous navigation on 4D objects and allows us to sense the bumps and holes in the fourth dimension. Preliminary tests of the software show that main features of the interface overcome some expected perceptual limitations in our interaction with 2D knot diagrams of 3D knots and 3D projective images of 4D mathematical objects.

  16. The Interplay among Gestures, Discourse, and Diagrams in Students' Geometrical Reasoning

    ERIC Educational Resources Information Center

    Chen, Chia-Ling; Herbst, Patricio

    2013-01-01

    This study explores interactions with diagrams that are involved in geometrical reasoning; more specifically, how students publicly make and justify conjectures through multimodal representations of diagrams. We describe how students interact with diagrams using both gestural and verbal modalities, and examine how such multimodal interactions with…

  17. Impulse-Momentum Diagrams

    ERIC Educational Resources Information Center

    Rosengrant, David

    2011-01-01

    Multiple representations are a valuable tool to help students learn and understand physics concepts. Furthermore, representations help students learn how to think and act like real scientists. These representations include: pictures, free-body diagrams, energy bar charts, electrical circuits, and, more recently, computer simulations and…

  18. Influence of Expectation and Campus Racial Climate on Undergraduates' Interracial Interaction

    ERIC Educational Resources Information Center

    Tamam, Ezhar; Idris, Fazilah; Tien, Wendy Yee Mei; Ahmad, Mona Alkauthar

    2013-01-01

    In this study, the authors examine the influence of interracial interaction expectation and campus racial climate perception on attitudes toward interracial interaction which, in turn, influences the levels of interracial interaction among students at a multicultural university in Malaysia. Interaction across race is fundamental to students'…

  19. Elementary diagrams in nuclear and neutron matter

    SciTech Connect

    Wiringa, R.B.

    1995-08-01

    Variational calculations of nuclear and neutron matter are currently performed using a diagrammatic cluster expansion with the aid of nonlinear integral equations for evaluating expectation values. These are the Fermi hypernetted chain (FHNC) and single-operator chain (SOC) equations, which are a way of doing partial diagram summations to infinite order. A more complete summation can be made by adding elementary diagrams to the procedure. The simplest elementary diagrams appear at the four-body cluster level; there is one such E{sub 4} diagram in Bose systems, but 35 diagrams in Fermi systems, which gives a level of approximation called FHNC/4. We developed a novel technique for evaluating these diagrams, by computing and storing 6 three-point functions, S{sub xyz}(r{sub 12}, r{sub 13}, r{sub 23}), where xyz (= ccd, cce, ddd, dde, dee, or eee) denotes the exchange character at the vertices 1, 2, and 3. All 35 Fermi E{sub 4} diagrams can be constructed from these 6 functions and other two-point functions that are already calculated. The elementary diagrams are known to be important in some systems like liquid {sup 3}He. We expect them to be small in nuclear matter at normal density, but they might become significant at higher densities appropriate for neutron star calculations. This year we programmed the FHNC/4 contributions to the energy and tested them in a number of simple model cases, including liquid {sup 3}He and Bethe`s homework problem. We get reasonable, but not exact agreement with earlier published work. In nuclear and neutron matter with the Argonne v{sub 14} interaction these contributions are indeed small corrections at normal density and grow to only 5-10 MeV/nucleon at 5 times normal density.

  20. Thermodynamic and topological phase diagrams of correlated topological insulators

    NASA Astrophysics Data System (ADS)

    Zdulski, Damian; Byczuk, Krzysztof

    2015-09-01

    A definition of topological phases of density matrices is presented. The topological invariants in case of both noninteracting and interacting systems are extended to nonzero temperatures. The influence of electron interactions on topological insulators at finite temperatures is investigated. A correlated topological insulator is described by the Kane-Mele model, which is extended by the interaction term of the Falicov-Kimball type. Within the Hartree-Fock and the Hubbard I approximations, thermodynamic and topological phase diagrams are determined where the long-range order is included. The results show that correlation effects lead to a strong suppression of the existence of the nontrivial topological phase. In the homogeneous phase, we find a purely correlation driven phase transition into the topologically trivial Mott insulator.

  1. An Instructional Strategy to Introduce Pedagogical Content Knowledge Using Venn Diagrams

    NASA Astrophysics Data System (ADS)

    Otto, Charlotte A.; Everett, Susan A.

    2013-03-01

    This paper describes the use of a three-circle Venn diagram as a vehicle for introducing pre-service elementary teachers to pedagogical content knowledge (PCK). Each circle of the diagram represents pedagogy, content and context individually. The overlap of any two circles represents the interaction between the circles. For example, the overlap of pedagogy and context relates to the ways that each of these general topics influences the other. The overlap of all three circles represents a complete lesson that is an integration of the three major components of PCK. The Venn diagram is an easily remembered graphic illustration of PCK that can be useful in planning lessons. The use of this graphic organizer in a science capstone course required of all pre-service elementary teachers is described.

  2. Time-temperature-transformation diagrams with more than one nose

    NASA Technical Reports Server (NTRS)

    Weinberg, Michael C.

    1992-01-01

    The structures of time-temperature-transformation diagrams of glasses which crystallize the combined homogeneous and heterogeneous crystallization mechanisms are examined. Considerations are given to the factors which might produce more than one extremum in such diagrams. Specific nucleation and growth models are used, and the influence of the parameters which appear in the nucleation and growth rate expressions upon the structure of the diagrams is evaluated.

  3. Tectonic discrimination diagrams revisited

    NASA Astrophysics Data System (ADS)

    Vermeesch, Pieter

    2006-06-01

    The decision boundaries of most tectonic discrimination diagrams are drawn by eye. Discriminant analysis is a statistically more rigorous way to determine the tectonic affinity of oceanic basalts based on their bulk-rock chemistry. This method was applied to a database of 756 oceanic basalts of known tectonic affinity (ocean island, mid-ocean ridge, or island arc). For each of these training data, up to 45 major, minor, and trace elements were measured. Discriminant analysis assumes multivariate normality. If the same covariance structure is shared by all the classes (i.e., tectonic affinities), the decision boundaries are linear, hence the term linear discriminant analysis (LDA). In contrast with this, quadratic discriminant analysis (QDA) allows the classes to have different covariance structures. To solve the statistical problems associated with the constant-sum constraint of geochemical data, the training data must be transformed to log-ratio space before performing a discriminant analysis. The results can be mapped back to the compositional data space using the inverse log-ratio transformation. An exhaustive exploration of 14,190 possible ternary discrimination diagrams yields the Ti-Si-Sr system as the best linear discrimination diagram and the Na-Nb-Sr system as the best quadratic discrimination diagram. The best linear and quadratic discrimination diagrams using only immobile elements are Ti-V-Sc and Ti-V-Sm, respectively. As little as 5% of the training data are misclassified by these discrimination diagrams. Testing them on a second database of 182 samples that were not part of the training data yields a more reliable estimate of future performance. Although QDA misclassifies fewer training data than LDA, the opposite is generally true for the test data. Therefore LDA is a cruder but more robust classifier than QDA. Another advantage of LDA is that it provides a powerful way to reduce the dimensionality of the multivariate geochemical data in a similar

  4. Preparation and Eh--pH diagrams of Fe(II)--Fe(III) green rust compounds; hyperfine interaction characteristics and stoichiometry of hydroxy-chloride, -sulphate and -carbonate

    NASA Astrophysics Data System (ADS)

    Génin, J.-M. R.; Refait, Ph.; Simon, L.; Drissi, S. H.

    1998-12-01

    Fe(II)--Fe(III) hydroxy-chloride, -sulphate and -carbonate were prepared by oxidation of a ferrous hydroxide precipitate in anion-containing aqueous solutions. The compounds are characterized by monitoring the redox potential Eh and the pH of stochiometric suspension vs time with the appropriate concentration ratios. X-ray diffraction allows us to characterize the crystal structure by distinguishing “green rust one” (GR1) from “green rust two” (GR2). Since green rusts (GRs) are of a pyroaurite-sjögrenite-like structure, i.e., consisting of intercalated foreign anions and water molecules in the interlayers between the brucite-like layers of Fe(OH)2, their chemical formulae can be determined from the Mössbauer spectra. Three quadrupole doublets are observed: D1 and D2 correspond to a ferrous state with isomershift IS of about 1.27 mm s-1 and quadrupole splittings QS of about 2.85 and 2.60 mm s-1, respectively, whereas D3 corresponds to a ferric state with IS and QS of about 0.4 mm s-1. The hyperfine parameters of these doublets are similar from one green rust to another but their intensity ratios vary considerably. Finally, Eh and pH equilibrium diagrams of the Fe species in the presence of chloride, sulphate and carbonate anions contained within the water solution are drawn and the thermodynamic conditions of existence and degrees of oxidation of green rusts are discussed.

  5. A technique for calculating the γ-matrix structures of the diagrams of a total four-fermion interaction with infinite number of vertices in d=2+ɛ dimensional regularization

    NASA Astrophysics Data System (ADS)

    Vasil'Ev, A. N.; Derkachev, S. É.; Kivel', N. A.

    1995-05-01

    It is known [1] that in d=2+ɛ dimensional regularization any four-fermion interaction generates an infinite number of counterterms of the form MediaObjects/11232_2005_BF02274026_f1.jpg , where 11232_2005_Article_BF02274026_TeX2GIFE1.gif γ _{α _1 ...α _n }^{(n)} equiv As[γ α _1 ...γ α _n ] is an antisymmetrized product of γ matrices. Therefore, a multiplicatively renormalizable complete model must include all such vertices, and the calcultion of the γ-matrix factors of its diagrams is a rather complicated problem. An effective technique for such calculations is proposed here. Its main elements are the realization of the γ matrices by the operators of a fermionic free field, transition to generating functions and functionals, the use of various functional forms of Wick's theorem, and reduction of the general d-dimensional problem to the case d=1. The general method is illustrated by specific calculations of the γ factors of one- and two-loop diagrams with arbitrary set of vertices γ (n) ⊗γ (n) .

  6. Impulse-Momentum Diagrams

    NASA Astrophysics Data System (ADS)

    Rosengrant, David

    2011-01-01

    Multiple representations are a valuable tool to help students learn and understand physics concepts. Furthermore, representations help students learn how to think and act like real scientists.2 These representations include: pictures, free-body diagrams,3 energy bar charts,4 electrical circuits, and, more recently, computer simulations and animations.5 However, instructors have limited choices when they want to help their students understand impulse and momentum. One of the only available options is the impulse-momentum bar chart.6 The bar charts can effectively show the magnitude of the momentum as well as help students understand conservation of momentum, but they do not easily show the actual direction. This paper highlights a new representation instructors can use to help their students with momentum and impulse—the impulse-momentum diagram (IMD).

  7. TEP process flow diagram

    SciTech Connect

    Wilms, R Scott; Carlson, Bryan; Coons, James; Kubic, William

    2008-01-01

    This presentation describes the development of the proposed Process Flow Diagram (PFD) for the Tokamak Exhaust Processing System (TEP) of ITER. A brief review of design efforts leading up to the PFD is followed by a description of the hydrogen-like, air-like, and waterlike processes. Two new design values are described; the mostcommon and most-demanding design values. The proposed PFD is shown to meet specifications under the most-common and mostdemanding design values.

  8. The Construction of Venn Diagrams.

    ERIC Educational Resources Information Center

    Grunbaum, Branko

    1984-01-01

    The study and use of "Venn diagrams" can lead to many interesting problems of a geometric, topological, or combinatorial character. The general nature of these diagrams is discussed and two new results are formulated. (JN)

  9. Prey type, vibrations and handling interactively influence spider silk expression.

    PubMed

    Blamires, S J; Chao, I-C; Tso, I-M

    2010-11-15

    The chemical and mechanical properties of spider major ampullate (MA) silks vary in response to different prey, mostly via differential expression of two genes - MaSp1 and MaSp2 - although the spinning process exerts additional influence over the mechanical properties of silk. The prey cues that initiate differential gene expression are unknown. Prey nutrients, vibratory stimuli and handling have been suggested to be influential. We performed experiments to decouple the vibratory stimuli and handling associated with high and low kinetic energy prey (crickets vs flies) from their prey nutrients to test the relative influence of each as inducers of silk protein expression in the orb web spider Nephila pilipes. We found that the MA silks from spiders feeding on live crickets had greater percentages of glutamine, serine, alanine and glycine than those from spiders feeding on live flies. Proline composition of the silks was unaffected by feeding treatment. Increases in alanine and glycine in the MA silks of the live-cricket-feeding spiders indicate a probable increase in MaSp1 gene expression. The amino acid compositions of N. pilipes feeding on crickets with fly stimuli and N. pilipes feeding on flies with cricket stimuli did not differ from each other or from pre-treatment responses, so these feeding treatments did not induce differential MaSp expression. Our results indicate that cricket vibratory stimuli and handling interact with nutrients to induce N. pilipes to adjust their gene expression to produce webs with mechanical properties appropriate for the retention of this prey. This shows that spiders can genetically alter their silk chemical compositions and, presumably, mechanical properties upon exposure to different prey types. The lack of any change in proline composition with feeding treatment in N. pilipes suggests that the MaSp model determined for Nephila clavipes is not universally applicable to all Nephila.

  10. Massive basketball diagram for a thermal scalar field theory

    SciTech Connect

    Andersen, Jens O.; Braaten, Eric; Strickland, Michael

    2000-08-15

    The ''basketball diagram'' is a three-loop vacuum diagram for a scalar field theory that cannot be expressed in terms of one-loop diagrams. We calculate this diagram for a massive scalar field at nonzero temperature, reducing it to expressions involving three-dimensional integrals that can be easily evaluated numerically. We use this result to calculate the free energy for a massive scalar field with a {phi}{sup 4} interaction to three-loop order. (c) 2000 The American Physical Society.

  11. Phase diagram of a truncated tetrahedral model.

    PubMed

    Krcmar, Roman; Gendiar, Andrej; Nishino, Tomotoshi

    2016-08-01

    Phase diagram of a discrete counterpart of the classical Heisenberg model, the truncated tetrahedral model, is analyzed on the square lattice, when the interaction is ferromagnetic. Each spin is represented by a unit vector that can point to one of the 12 vertices of the truncated tetrahedron, which is a continuous interpolation between the tetrahedron and the octahedron. Phase diagram of the model is determined by means of the statistical analog of the entanglement entropy, which is numerically calculated by the corner transfer matrix renormalization group method. The obtained phase diagram consists of four different phases, which are separated by five transition lines. In the parameter region, where the octahedral anisotropy is dominant, a weak first-order phase transition is observed. PMID:27627273

  12. Phase diagram of a truncated tetrahedral model

    NASA Astrophysics Data System (ADS)

    Krcmar, Roman; Gendiar, Andrej; Nishino, Tomotoshi

    2016-08-01

    Phase diagram of a discrete counterpart of the classical Heisenberg model, the truncated tetrahedral model, is analyzed on the square lattice, when the interaction is ferromagnetic. Each spin is represented by a unit vector that can point to one of the 12 vertices of the truncated tetrahedron, which is a continuous interpolation between the tetrahedron and the octahedron. Phase diagram of the model is determined by means of the statistical analog of the entanglement entropy, which is numerically calculated by the corner transfer matrix renormalization group method. The obtained phase diagram consists of four different phases, which are separated by five transition lines. In the parameter region, where the octahedral anisotropy is dominant, a weak first-order phase transition is observed.

  13. Situational influences on rhythmicity in speech, music, and their interaction.

    PubMed

    Hawkins, Sarah

    2014-12-19

    Brain processes underlying the production and perception of rhythm indicate considerable flexibility in how physical signals are interpreted. This paper explores how that flexibility might play out in rhythmicity in speech and music. There is much in common across the two domains, but there are also significant differences. Interpretations are explored that reconcile some of the differences, particularly with respect to how functional properties modify the rhythmicity of speech, within limits imposed by its structural constraints. Functional and structural differences mean that music is typically more rhythmic than speech, and that speech will be more rhythmic when the emotions are more strongly engaged, or intended to be engaged. The influence of rhythmicity on attention is acknowledged, and it is suggested that local increases in rhythmicity occur at times when attention is required to coordinate joint action, whether in talking or music-making. Evidence is presented which suggests that while these short phases of heightened rhythmical behaviour are crucial to the success of transitions in communicative interaction, their modality is immaterial: they all function to enhance precise temporal prediction and hence tightly coordinated joint action. PMID:25385776

  14. Situational influences on rhythmicity in speech, music, and their interaction

    PubMed Central

    Hawkins, Sarah

    2014-01-01

    Brain processes underlying the production and perception of rhythm indicate considerable flexibility in how physical signals are interpreted. This paper explores how that flexibility might play out in rhythmicity in speech and music. There is much in common across the two domains, but there are also significant differences. Interpretations are explored that reconcile some of the differences, particularly with respect to how functional properties modify the rhythmicity of speech, within limits imposed by its structural constraints. Functional and structural differences mean that music is typically more rhythmic than speech, and that speech will be more rhythmic when the emotions are more strongly engaged, or intended to be engaged. The influence of rhythmicity on attention is acknowledged, and it is suggested that local increases in rhythmicity occur at times when attention is required to coordinate joint action, whether in talking or music-making. Evidence is presented which suggests that while these short phases of heightened rhythmical behaviour are crucial to the success of transitions in communicative interaction, their modality is immaterial: they all function to enhance precise temporal prediction and hence tightly coordinated joint action. PMID:25385776

  15. Situational influences on rhythmicity in speech, music, and their interaction.

    PubMed

    Hawkins, Sarah

    2014-12-19

    Brain processes underlying the production and perception of rhythm indicate considerable flexibility in how physical signals are interpreted. This paper explores how that flexibility might play out in rhythmicity in speech and music. There is much in common across the two domains, but there are also significant differences. Interpretations are explored that reconcile some of the differences, particularly with respect to how functional properties modify the rhythmicity of speech, within limits imposed by its structural constraints. Functional and structural differences mean that music is typically more rhythmic than speech, and that speech will be more rhythmic when the emotions are more strongly engaged, or intended to be engaged. The influence of rhythmicity on attention is acknowledged, and it is suggested that local increases in rhythmicity occur at times when attention is required to coordinate joint action, whether in talking or music-making. Evidence is presented which suggests that while these short phases of heightened rhythmical behaviour are crucial to the success of transitions in communicative interaction, their modality is immaterial: they all function to enhance precise temporal prediction and hence tightly coordinated joint action.

  16. Phase diagram of QCD

    SciTech Connect

    Halasz, M.A.; Verbaarschot, J.J.; Jackson, A.D.; Shrock, R.E.; Stephanov, M.A.

    1998-11-01

    We analyze the phase diagram of QCD with two massless quark flavors in the space of temperature T and chemical potential of the baryon charge {mu} using available experimental knowledge of QCD, insights gained from various models, as well as general and model independent arguments including continuity, universality, and thermodynamic relations. A random matrix model is used to describe the chiral symmetry restoration phase transition at finite T and {mu}. In agreement with general arguments, this model predicts a tricritical point in the T{mu} plane. Certain critical properties at such a point are universal and can be relevant to heavy ion collision experiments. {copyright} {ital 1998} {ital The American Physical Society}

  17. Knot probabilities in random diagrams

    NASA Astrophysics Data System (ADS)

    Cantarella, Jason; Chapman, Harrison; Mastin, Matt

    2016-10-01

    We consider a natural model of random knotting—choose a knot diagram at random from the finite set of diagrams with n crossings. We tabulate diagrams with 10 and fewer crossings and classify the diagrams by knot type, allowing us to compute exact probabilities for knots in this model. As expected, most diagrams with 10 and fewer crossings are unknots (about 78% of the roughly 1.6 billion 10 crossing diagrams). For these crossing numbers, the unknot fraction is mostly explained by the prevalence of ‘tree-like’ diagrams which are unknots for any assignment of over/under information at crossings. The data shows a roughly linear relationship between the log of knot type probability and the log of the frequency rank of the knot type, analogous to Zipf’s law for word frequency. The complete tabulation and all knot frequencies are included as supplementary data.

  18. Wilson Loop Diagrams and Positroids

    NASA Astrophysics Data System (ADS)

    Agarwala, Susama; Marin-Amat, Eloi

    2016-07-01

    In this paper, we study a new application of the positive Grassmannian to Wilson loop diagrams (or MHV diagrams) for scattering amplitudes in N= 4 Super Yang-Mill theory (N = 4 SYM). There has been much interest in studying this theory via the positive Grassmannians using BCFW recursion. This is the first attempt to study MHV diagrams for planar Wilson loop calculations (or planar amplitudes) in terms of positive Grassmannians. We codify Wilson loop diagrams completely in terms of matroids. This allows us to apply the combinatorial tools in matroid theory used to identify positroids (non-negative Grassmannians) to Wilson loop diagrams. In doing so, we find that certain non-planar Wilson loop diagrams define positive Grassmannians. While non-planar diagrams do not have physical meaning, this finding suggests that they may have value as an algebraic tool, and deserve further investigation.

  19. Warped penguin diagrams

    SciTech Connect

    Csaki, Csaba; Grossman, Yuval; Tanedo, Philip; Tsai, Yuhsin

    2011-04-01

    We present an analysis of the loop-induced magnetic dipole operator in the Randall-Sundrum model of a warped extra dimension with anarchic bulk fermions and an IR brane-localized Higgs. These operators are finite at one-loop order and we explicitly calculate the branching ratio for {mu}{yields}e{gamma} using the mixed position/momentum space formalism. The particular bound on the anarchic Yukawa and Kaluza-Klein (KK) scales can depend on the flavor structure of the anarchic matrices. It is possible for a generic model to either be ruled out or unaffected by these bounds without any fine-tuning. We quantify how these models realize this surprising behavior. We also review tree-level lepton flavor bounds in these models and show that these are on the verge of tension with the {mu}{yields}e{gamma} bounds from typical models with a 3 TeV Kaluza-Klein scale. Further, we illuminate the nature of the one-loop finiteness of these diagrams and show how to accurately determine the degree of divergence of a five-dimensional loop diagram using both the five-dimensional and KK formalism. This power counting can be obfuscated in the four-dimensional Kaluza-Klein formalism and we explicitly point out subtleties that ensure that the two formalisms agree. Finally, we remark on the existence of a perturbative regime in which these one-loop results give the dominant contribution.

  20. Spin wave Feynman diagram vertex computation package

    NASA Astrophysics Data System (ADS)

    Price, Alexander; Javernick, Philip; Datta, Trinanjan

    Spin wave theory is a well-established theoretical technique that can correctly predict the physical behavior of ordered magnetic states. However, computing the effects of an interacting spin wave theory incorporating magnons involve a laborious by hand derivation of Feynman diagram vertices. The process is tedious and time consuming. Hence, to improve productivity and have another means to check the analytical calculations, we have devised a Feynman Diagram Vertex Computation package. In this talk, we will describe our research group's effort to implement a Mathematica based symbolic Feynman diagram vertex computation package that computes spin wave vertices. Utilizing the non-commutative algebra package NCAlgebra as an add-on to Mathematica, symbolic expressions for the Feynman diagram vertices of a Heisenberg quantum antiferromagnet are obtained. Our existing code reproduces the well-known expressions of a nearest neighbor square lattice Heisenberg model. We also discuss the case of a triangular lattice Heisenberg model where non collinear terms contribute to the vertex interactions.

  1. Consumer trait variation influences tritrophic interactions in salt marsh communities

    PubMed Central

    Hughes, Anne Randall; Hanley, Torrance C; Orozco, Nohelia P; Zerebecki, Robyn A

    2015-01-01

    The importance of intraspecific variation has emerged as a key question in community ecology, helping to bridge the gap between ecology and evolution. Although much of this work has focused on plant species, recent syntheses have highlighted the prevalence and potential importance of morphological, behavioral, and life history variation within animals for ecological and evolutionary processes. Many small-bodied consumers live on the plant that they consume, often resulting in host plant-associated trait variation within and across consumer species. Given the central position of consumer species within tritrophic food webs, such consumer trait variation may play a particularly important role in mediating trophic dynamics, including trophic cascades. In this study, we used a series of field surveys and laboratory experiments to document intraspecific trait variation in a key consumer species, the marsh periwinkle Littoraria irrorata, based on its host plant species (Spartina alterniflora or Juncus roemerianus) in a mixed species assemblage. We then conducted a 12-week mesocosm experiment to examine the effects of Littoraria trait variation on plant community structure and dynamics in a tritrophic salt marsh food web. Littoraria from different host plant species varied across a suite of morphological and behavioral traits. These consumer trait differences interacted with plant community composition and predator presence to affect overall plant stem height, as well as differentially alter the density and biomass of the two key plant species in this system. Whether due to genetic differences or phenotypic plasticity, trait differences between consumer types had significant ecological consequences for the tritrophic marsh food web over seasonal time scales. By altering the cascading effects of the top predator on plant community structure and dynamics, consumer differences may generate a feedback over longer time scales, which in turn influences the degree of trait

  2. Consumer trait variation influences tritrophic interactions in salt marsh communities.

    PubMed

    Hughes, Anne Randall; Hanley, Torrance C; Orozco, Nohelia P; Zerebecki, Robyn A

    2015-07-01

    The importance of intraspecific variation has emerged as a key question in community ecology, helping to bridge the gap between ecology and evolution. Although much of this work has focused on plant species, recent syntheses have highlighted the prevalence and potential importance of morphological, behavioral, and life history variation within animals for ecological and evolutionary processes. Many small-bodied consumers live on the plant that they consume, often resulting in host plant-associated trait variation within and across consumer species. Given the central position of consumer species within tritrophic food webs, such consumer trait variation may play a particularly important role in mediating trophic dynamics, including trophic cascades. In this study, we used a series of field surveys and laboratory experiments to document intraspecific trait variation in a key consumer species, the marsh periwinkle Littoraria irrorata, based on its host plant species (Spartina alterniflora or Juncus roemerianus) in a mixed species assemblage. We then conducted a 12-week mesocosm experiment to examine the effects of Littoraria trait variation on plant community structure and dynamics in a tritrophic salt marsh food web. Littoraria from different host plant species varied across a suite of morphological and behavioral traits. These consumer trait differences interacted with plant community composition and predator presence to affect overall plant stem height, as well as differentially alter the density and biomass of the two key plant species in this system. Whether due to genetic differences or phenotypic plasticity, trait differences between consumer types had significant ecological consequences for the tritrophic marsh food web over seasonal time scales. By altering the cascading effects of the top predator on plant community structure and dynamics, consumer differences may generate a feedback over longer time scales, which in turn influences the degree of trait

  3. Program Synthesizes UML Sequence Diagrams

    NASA Technical Reports Server (NTRS)

    Barry, Matthew R.; Osborne, Richard N.

    2006-01-01

    A computer program called "Rational Sequence" generates Universal Modeling Language (UML) sequence diagrams of a target Java program running on a Java virtual machine (JVM). Rational Sequence thereby performs a reverse engineering function that aids in the design documentation of the target Java program. Whereas previously, the construction of sequence diagrams was a tedious manual process, Rational Sequence generates UML sequence diagrams automatically from the running Java code.

  4. Feynchois:. a Feynman Diagram Generator

    NASA Astrophysics Data System (ADS)

    Choi, Chul-Woo; Gonsalves, Richard J.

    A Feynman diagram generator, named FeynChois, is described. It provides the user with a full GUI (Graphical User Interface) environment which enables the generation diagrams automatically with several mouse operations. The diagram generator is built on an Application Programming Interface (API) called ViewableBeans which provides a framework for programming graphically representable objects. We also present a means for describing Feynman rules in a computer friendly manner using the XML (Extensible Markup Language) format.

  5. The Factors Influencing Young Children's Social Interaction in Technology Integration

    ERIC Educational Resources Information Center

    Lim, Eun Mee

    2015-01-01

    When technology integration is accomplished successfully in early childhood education settings, children tend to interact more with one another and exchange information related to computer tasks as well as the overall classroom on-going curriculum themes. Therefore, to explore how young children are interacting in computer areas when using…

  6. Framing matters: contextual influences on interracial interaction outcomes.

    PubMed

    Babbitt, Laura G; Sommers, Samuel R

    2011-09-01

    Previous studies indicate that interracial interactions frequently have negative outcomes but have typically focused on social contexts. The current studies examined the effect of manipulating interaction context. In Study 1, Black and White participants worked together with instructions that created either a social focus or a task focus. With a task focus, interracial pairs were more consistently synchronized, Black participants showed less executive function depletion, and White participants generally showed reduced implicit bias. Follow-up studies suggested that prejudice concerns help explain these findings: White participants reported fewer concerns about appearing prejudiced when they imagined an interracial interaction with a task focus rather than a social focus (Study 2a), and Black participants reported less vigilance against prejudice in an imagined interracial interaction with a task focus rather than a social focus (Study 2b). Taken together, these studies illustrate the importance of interaction context for the experiences of both Blacks and Whites.

  7. The influence of interspecific interactions on species range expansion rates

    PubMed Central

    Svenning, Jens-Christian; Gravel, Dominique; Holt, Robert D.; Schurr, Frank M.; Thuiller, Wilfried; Münkemüller, Tamara; Schiffers, Katja H.; Dullinger, Stefan; Edwards, Thomas C.; Hickler, Thomas; Higgins, Steven I.; Nabel, Julia E. M. S.; Pagel, Jörn; Normand, Signe

    2014-01-01

    Ongoing and predicted global change makes understanding and predicting species’ range shifts an urgent scientific priority. Here, we provide a synthetic perspective on the so far poorly understood effects of interspecific interactions on range expansion rates. We present theoretical foundations for how interspecific interactions may modulate range expansion rates, consider examples from empirical studies of biological invasions and natural range expansions as well as process-based simulations, and discuss how interspecific interactions can be more broadly represented in process-based, spatiotemporally explicit range forecasts. Theory tells us that interspecific interactions affect expansion rates via alteration of local population growth rates and spatial displacement rates, but also via effects on other demographic parameters. The best empirical evidence for interspecific effects on expansion rates comes from studies of biological invasions. Notably, invasion studies indicate that competitive dominance and release from specialized enemies can enhance expansion rates. Studies of natural range expansions especially point to the potential for competition from resident species to reduce expansion rates. Overall, it is clear that interspecific interactions may have important consequences for range dynamics, but also that their effects have received too little attention to robustly generalize on their importance. We then discuss how interspecific interactions effects can be more widely incorporated in dynamic modeling of range expansions. Importantly, models must describe spatiotemporal variation in both local population dynamics and dispersal. Finally, we derive the following guidelines for when it is particularly important to explicitly represent interspecific interactions in dynamic range expansion forecasts: if most interacting species show correlated spatial or temporal trends in their effects on the target species, if the number of interacting species is low

  8. The influence of interspecific interactions on species range expansion rates

    USGS Publications Warehouse

    Svenning, Jens-Christian; Gravel, Dominique; Holt, Robert D.; Schurr, Frank M.; Thuiller, Wilfried; Münkemüller, Tamara; Schiffers, Katja H.; Dullinger, Stefan; Edwards, Thomas C.; Hickler, Thomas; Higgins, Steven I.; Nabel, Julia E.M.S.; Pagel, Jörn; Normand, Signe

    2014-01-01

    Ongoing and predicted global change makes understanding and predicting species’ range shifts an urgent scientific priority. Here, we provide a synthetic perspective on the so far poorly understood effects of interspecific interactions on range expansion rates. We present theoretical foundations for how interspecific interactions may modulate range expansion rates, consider examples from empirical studies of biological invasions and natural range expansions as well as process-based simulations, and discuss how interspecific interactions can be more broadly represented in process-based, spatiotemporally explicit range forecasts. Theory tells us that interspecific interactions affect expansion rates via alteration of local population growth rates and spatial displacement rates, but also via effects on other demographic parameters. The best empirical evidence for interspecific effects on expansion rates comes from studies of biological invasions. Notably, invasion studies indicate that competitive dominance and release from specialized enemies can enhance expansion rates. Studies of natural range expansions especially point to the potential for competition from resident species to reduce expansion rates. Overall, it is clear that interspecific interactions may have important consequences for range dynamics, but also that their effects have received too little attention to robustly generalize on their importance. We then discuss how interspecific interactions effects can be more widely incorporated in dynamic modeling of range expansions. Importantly, models must describe spatiotemporal variation in both local population dynamics and dispersal. Finally, we derive the following guidelines for when it is particularly important to explicitly represent interspecific interactions in dynamic range expansion forecasts: if most interacting species show correlated spatial or temporal trends in their effects on the target species, if the number of interacting species is low

  9. Diagonal Slices of 3D Young Diagrams in the Approach of Maya Diagrams

    NASA Astrophysics Data System (ADS)

    Cai, Li-Qiang; Wang, Li-Fang; Wu, Ke; Yang, Jie

    2014-09-01

    According to the correspondence between 2D Young diagrams and Maya diagrams and the relation between 2D and 3D Young diagrams, we construct 3D Young diagrams in the approach of Maya diagrams. Moreover, we formulate the generating function of 3D Young diagrams, which is the MacMahon function in terms of Maya diagrams.

  10. The Influence of Ethnicity, Gender, and Dyadic Composition on Uncertainty Reduction in Initial Interactions.

    ERIC Educational Resources Information Center

    Gudykunst, William B.; Hammer, Mitchell R.

    1987-01-01

    Observation of 485 Black and White students demonstrates that ethnicity and self-monitoring have independent influences upon uncertainty reduction in initial interactions, while the effects of gender and dyadic composition are interactive in nature. Many of the relationships between interaction variables posited by Berger and Calabrese are…

  11. On Public Influence on People's Interactions with Ordinary Biodiversity.

    PubMed

    Skandrani, Zina; Daniel, Lucie; Jacquelin, Lauriane; Leboucher, Gérard; Bovet, Dalila; Prévot, Anne-Caroline

    2015-01-01

    Besides direct impacts of urban biodiversity on local ecosystem services, the contact of city dwellers with urban nature in their everyday life could increase their awareness on conservation issues. In this paper, we focused on a particularly common animal urban species, the feral pigeon Columba livia. Through an observational approach, we examined behavioral interactions between city dwellers and this species in the Paris metropolis, France. We found that most people (mean: 81%) do not interact with pigeons. Further, interactions (either positive or negative) are context and age-dependent: children interact more than adults and the elderly, while people in tourist spots interact more than people in urban parks or in railway stations, a result that suggests that people interacting with pigeons are mostly tourists. We discuss these results in terms of public normative pressures on city dwellers' access to and reconnection with urban nature. We call for caution in how urban species are publically portrayed and managed, given the importance of interactions with ordinary biodiversity for the fate of nature conservation. PMID:26154622

  12. INTERACTIVITY INFLUENCES THE MAGNITUDE OF VIRTUAL REALITY ANALGESIA

    PubMed Central

    Wender, Regina; Hoffman, Hunter G.; Hunner, Harley H.; Seibel, Eric J.; Patterson, David R.; Sharar, Sam R.

    2009-01-01

    Despite medication with opioids and other powerful pharmacologic pain medications, most patients rate their pain during severe burn wound care as severe to excruciating. Excessive pain is a widespread medical problem in a wide range of patient populations. Immersive virtual reality (VR) distraction may help reduce pain associated with medical procedures. Recent research manipulating immersiveness has shown that a high tech VR helmet reduces pain more effectively than a low tech VR helmet. The present study explores the effect of interactivity on the analgesic effectiveness of virtual reality. Using a double blind design, in the present study, twenty-one volunteers were randomly assigned to one of two groups, and received a thermal pain stimulus during either interactive VR, or during non-interactive VR. Subjects in both groups individually glided through the virtual world, but one group could look around and interact with the environment using the trackball, whereas participants in the other group had no trackball. Afterwards, each participant provided subjective 0–10 ratings of cognitive, sensory and affective components of pain, and the amount of fun during the pain stimulus. Compared to the non-interactive VR group, participants in the interactive VR group showed 75% more reduction in pain unpleasantness (p < .005) and 74% more reduction in worst pain (p < .005). Interactivity increased the analgesic effectiveness of immersive virtual reality. PMID:20390047

  13. INTERACTIVITY INFLUENCES THE MAGNITUDE OF VIRTUAL REALITY ANALGESIA.

    PubMed

    Wender, Regina; Hoffman, Hunter G; Hunner, Harley H; Seibel, Eric J; Patterson, David R; Sharar, Sam R

    2009-01-01

    Despite medication with opioids and other powerful pharmacologic pain medications, most patients rate their pain during severe burn wound care as severe to excruciating. Excessive pain is a widespread medical problem in a wide range of patient populations. Immersive virtual reality (VR) distraction may help reduce pain associated with medical procedures. Recent research manipulating immersiveness has shown that a high tech VR helmet reduces pain more effectively than a low tech VR helmet. The present study explores the effect of interactivity on the analgesic effectiveness of virtual reality. Using a double blind design, in the present study, twenty-one volunteers were randomly assigned to one of two groups, and received a thermal pain stimulus during either interactive VR, or during non-interactive VR. Subjects in both groups individually glided through the virtual world, but one group could look around and interact with the environment using the trackball, whereas participants in the other group had no trackball. Afterwards, each participant provided subjective 0-10 ratings of cognitive, sensory and affective components of pain, and the amount of fun during the pain stimulus. Compared to the non-interactive VR group, participants in the interactive VR group showed 75% more reduction in pain unpleasantness (p < .005) and 74% more reduction in worst pain (p < .005). Interactivity increased the analgesic effectiveness of immersive virtual reality.

  14. On Public Influence on People's Interactions with Ordinary Biodiversity.

    PubMed

    Skandrani, Zina; Daniel, Lucie; Jacquelin, Lauriane; Leboucher, Gérard; Bovet, Dalila; Prévot, Anne-Caroline

    2015-01-01

    Besides direct impacts of urban biodiversity on local ecosystem services, the contact of city dwellers with urban nature in their everyday life could increase their awareness on conservation issues. In this paper, we focused on a particularly common animal urban species, the feral pigeon Columba livia. Through an observational approach, we examined behavioral interactions between city dwellers and this species in the Paris metropolis, France. We found that most people (mean: 81%) do not interact with pigeons. Further, interactions (either positive or negative) are context and age-dependent: children interact more than adults and the elderly, while people in tourist spots interact more than people in urban parks or in railway stations, a result that suggests that people interacting with pigeons are mostly tourists. We discuss these results in terms of public normative pressures on city dwellers' access to and reconnection with urban nature. We call for caution in how urban species are publically portrayed and managed, given the importance of interactions with ordinary biodiversity for the fate of nature conservation.

  15. Potential-pH Diagrams.

    ERIC Educational Resources Information Center

    Barnum, Dennis W.

    1982-01-01

    Potential-pH diagrams show the domains of redoxpotential and pH in which major species are most stable. Constructing such diagrams provides students with opportunities to decide what species must be considered, search literature for equilibrium constants and free energies of formation, and practice in using the Nernst equation. (Author/JN)

  16. Particle–hole ring diagrams for fermions in two dimensions

    SciTech Connect

    Kaiser, N.

    2014-11-15

    The set of particle–hole ring diagrams for a many-fermion system in two dimensions is studied. The complex-valued polarization function is derived in detail and shown to be expressible in terms of square-root functions. For a contact-interaction the perturbative contributions to the energy per particle Ē(k{sub f}) are calculated in a closed analytical form from third up to twelfth order. The resummation of the particle–hole ring diagrams to all orders is studied and a pronounced dependence on the dimensionless coupling parameter α is found. There is a substantial difference between the complete ring-sum with all exchange-type diagrams included and the standard resummation of the leading n-ring diagrams only. The spin factor S{sub n}(g) associated to the nth order ring diagrams is derived for arbitrary spin-degeneracy g.

  17. Phase diagrams of diblock copolymers in electric fields: a self-consistent field theory study.

    PubMed

    Wu, Ji; Wang, Xianghong; Ji, Yongyun; He, Linli; Li, Shiben

    2016-04-21

    We investigated the phase diagrams of diblock copolymers in external electrostatic fields by using real-space self-consistent field theory. The lamella, cylinder, sphere, and ellipsoid structures were observed and analyzed by their segment distributions, which were arranged to two types of phase diagrams to examine the phase behavior in weak and strong electric fields. One type was constructed on the basis of Flory-Huggins interaction parameter and volume fraction. We identified an ellipsoid structure with a body-centered cuboid arrangement as a stable phase and discussed the shift of phase boundaries in the electric fields. The other type of phase diagrams was established on the basis of the dielectric constants of two blocks in the electric fields. We then determined the regions of ellipsoid phase in the phase diagrams to examine the influence of dielectric constants on the phase transition between ellipsoidal and hexagonally packed cylinder phases. A general agreement was obtained by comparing our results with those described in previous experimental and theoretical studies. PMID:27020849

  18. Failure Assessment Diagram for Titanium Brazed Joints

    NASA Technical Reports Server (NTRS)

    Flom, Yury; Jones, Justin S.; Powell, Mollie M.; Puckett, David F.

    2011-01-01

    The interaction equation was used to predict failure in Ti-4V-6Al joints brazed with Al 1100 filler metal. The joints used in this study were geometrically similar to the joints in the brazed beryllium metering structure considered for the ATLAS telescope. This study confirmed that the interaction equation R(sub sigma) + R(sub Tau) = 1, where R(sub sigma) and R(sub Tau)are normal and shear stress ratios, can be used as conservative lower bound estimate of the failure criterion in ATLAS brazed joints as well as for construction of the Failure Assessment Diagram (FAD).

  19. Penguin-like diagrams from the standard model

    NASA Astrophysics Data System (ADS)

    Ping, Chia Swee

    2015-04-01

    The Standard Model is highly successful in describing the interactions of leptons and quarks. There are, however, rare processes that involve higher order effects in electroweak interactions. One specific class of processes is the penguin-like diagram. Such class of diagrams involves the neutral change of quark flavours accompanied by the emission of a gluon (gluon penguin), a photon (photon penguin), a gluon and a photon (gluon-photon penguin), a Z-boson (Z penguin), or a Higgs-boson (Higgs penguin). Such diagrams do not arise at the tree level in the Standard Model. They are, however, induced by one-loop effects. In this paper, we present an exact calculation of the penguin diagram vertices in the `tHooft-Feynman gauge. Renormalization of the vertex is effected by a prescription by Chia and Chong which gives an expression for the counter term identical to that obtained by employing Ward-Takahashi identity. The on-shell vertex functions for the penguin diagram vertices are obtained. The various penguin diagram vertex functions are related to one another via Ward-Takahashi identity. From these, a set of relations is obtained connecting the vertex form factors of various penguin diagrams. Explicit expressions for the gluon-photon penguin vertex form factors are obtained, and their contributions to the flavor changing processes estimated.

  20. Penguin-like diagrams from the standard model

    SciTech Connect

    Ping, Chia Swee

    2015-04-24

    The Standard Model is highly successful in describing the interactions of leptons and quarks. There are, however, rare processes that involve higher order effects in electroweak interactions. One specific class of processes is the penguin-like diagram. Such class of diagrams involves the neutral change of quark flavours accompanied by the emission of a gluon (gluon penguin), a photon (photon penguin), a gluon and a photon (gluon-photon penguin), a Z-boson (Z penguin), or a Higgs-boson (Higgs penguin). Such diagrams do not arise at the tree level in the Standard Model. They are, however, induced by one-loop effects. In this paper, we present an exact calculation of the penguin diagram vertices in the ‘tHooft-Feynman gauge. Renormalization of the vertex is effected by a prescription by Chia and Chong which gives an expression for the counter term identical to that obtained by employing Ward-Takahashi identity. The on-shell vertex functions for the penguin diagram vertices are obtained. The various penguin diagram vertex functions are related to one another via Ward-Takahashi identity. From these, a set of relations is obtained connecting the vertex form factors of various penguin diagrams. Explicit expressions for the gluon-photon penguin vertex form factors are obtained, and their contributions to the flavor changing processes estimated.

  1. The Features of Interactive Whiteboards and Their Influence on Learning

    ERIC Educational Resources Information Center

    Kennewell, Steve; Beauchamp, Gary

    2007-01-01

    In a small-scale study of Information and Communication Technology (ICT)-rich primary school, interactive whiteboards (IWBs) were found to be the predominant ICT tools used by teachers. The study sought to identify how the teachers used features of ICT to enhance learning, based on a list of ICT's functions published for teacher education…

  2. Magnetic Interactions Influence the Properties of Helium Defects in Iron.

    SciTech Connect

    Seletskaia, Tatiana; Osetskiy, Yury N; Stoller, Roger E; Stocks, George Malcolm

    2005-01-01

    Density functional theory calculations of He defect properties in iron have shown an unexpected influence of magnetism arising from the defect's electronic structure. In contrast with previous work that neglected such effects, the results indicate that the tetrahedral position is energetically more favorable for the He interstitial than the octahedral site. This may have significant implications for He clustering and bubble nucleation, which will impact material performance in future fusion reactors. These results provide the basis for development of improved atomistic models.

  3. Cryptococcus and Phagocytes: Complex Interactions that Influence Disease Outcome.

    PubMed

    Leopold Wager, Chrissy M; Hole, Camaron R; Wozniak, Karen L; Wormley, Floyd L

    2016-01-01

    Cryptococcus neoformans and C. gattii are fungal pathogens that cause life-threatening disease. These fungi commonly enter their host via inhalation into the lungs where they encounter resident phagocytes, including macrophages and dendritic cells, whose response has a pronounced impact on the outcome of disease. Cryptococcus has complex interactions with the resident and infiltrating innate immune cells that, ideally, result in destruction of the yeast. These phagocytic cells have pattern recognition receptors that allow recognition of specific cryptococcal cell wall and capsule components. However, Cryptococcus possesses several virulence factors including a polysaccharide capsule, melanin production and secretion of various enzymes that aid in evasion of the immune system or enhance its ability to thrive within the phagocyte. This review focuses on the intricate interactions between the cryptococci and innate phagocytic cells including discussion of manipulation and evasion strategies used by Cryptococcus, anti-cryptococcal responses by the phagocytes and approaches for targeting phagocytes for the development of novel immunotherapeutics. PMID:26903984

  4. Cryptococcus and Phagocytes: Complex Interactions that Influence Disease Outcome

    PubMed Central

    Leopold Wager, Chrissy M.; Hole, Camaron R.; Wozniak, Karen L.; Wormley, Floyd L.

    2016-01-01

    Cryptococcus neoformans and C. gattii are fungal pathogens that cause life-threatening disease. These fungi commonly enter their host via inhalation into the lungs where they encounter resident phagocytes, including macrophages and dendritic cells, whose response has a pronounced impact on the outcome of disease. Cryptococcus has complex interactions with the resident and infiltrating innate immune cells that, ideally, result in destruction of the yeast. These phagocytic cells have pattern recognition receptors that allow recognition of specific cryptococcal cell wall and capsule components. However, Cryptococcus possesses several virulence factors including a polysaccharide capsule, melanin production and secretion of various enzymes that aid in evasion of the immune system or enhance its ability to thrive within the phagocyte. This review focuses on the intricate interactions between the cryptococci and innate phagocytic cells including discussion of manipulation and evasion strategies used by Cryptococcus, anti-cryptococcal responses by the phagocytes and approaches for targeting phagocytes for the development of novel immunotherapeutics. PMID:26903984

  5. A spinor technique in symbolic Feynman diagram calculation mesons

    SciTech Connect

    A. Pang; C. Ji

    1994-02-17

    The authors present a recursive diagrammatic method for evaluating tree-level Feynman diagrams involving multi-fermions which interact through gauge bosons (gluons or photons). Based on this method, a package called COMPUTE, which can generate and calculate all the possible Feynman diagrams for exclusive processes in perturbative QCD, has been developed (available in both Mathematics and Maple). As an example, a calculation of the nucleon Compton scattering amplitude is given.

  6. Cooperative or Anticooperative: How Noncovalent Interactions Influence Each Other.

    PubMed

    Saha, Soumen; Sastry, G Narahari

    2015-08-27

    This computational study examines the key factors that control the structures and energetics of the coexistence of multiple noncovalent interactions. 4-Amino-2-iodophenol is taken as a model that exhibits nine different kinds of noncovalent interactions, viz., cation-π (CP), hydrogen bond (HB) through O (OHB), HB through N (NHB), halogen bond (XB), π-π (PP), metal ion-lone pair (ML) through O (OML), ML through N (NML), charge assisted hydrogen bond (CHB) through O (OCHB), and CHB through N (NCHB). Through all possible combinations of these noncovalent interactions, based on energy, geometry, charge, and atoms in molecules (AIM) analysis, we have systematically analyzed the cooperativity among 40 ternary systems and 105 quaternary systems. We have observed that CP-HB, CP-XB, CP-PP, HB-HB, HB-XB, HB-PP, HB-ML, HB-CHB, XB-PP, XB-ML, XB-CHB, PP-ML, and PP-OCHB can form cooperative ternary systems. While studying the quaternary systems, we have observed that HB, XB, and PP work together by enhancing each other's strength. The study highlights that the positively charged species enhances HB-HB and HB-PP interactions and forms cooperative HB-HB-CHB, HB-HB-ML, HB-PP-ML, and HB-PP-CHB systems. Surprisingly, OHB-OML-NML, OHB-OML-OCHB, OHB-OML-NCHB, OHB-NML-OCHB, NHB-OML-NML, NHB-OML-NCHB, and NHB-NML-OCHB are also cooperative in nature despite the electrostatic repulsion between two positive charge species. The current study shows the widespread presence of cooperativity as well as anticooperativity in supramolecular assembles.

  7. Cyanogenic Pseudomonads Influence Multitrophic Interactions in the Rhizosphere

    PubMed Central

    Rudrappa, Thimmaraju; Splaine, Robert E.; Biedrzycki, Meredith L.; Bais, Harsh P.

    2008-01-01

    In the rhizosphere, plant roots cope with both pathogenic and beneficial bacterial interactions. The exometabolite production in certain bacterial species may regulate root growth and other root-microbe interactions in the rhizosphere. Here, we elucidated the role of cyanide production in pseudomonad virulence affecting plant root growth and other rhizospheric processes. Exposure of Arabidopsis thaliana Col-0 seedlings to both direct (with KCN) and indirect forms of cyanide from different pseudomonad strains caused significant inhibition of primary root growth. Further, we report that this growth inhibition was caused by the suppression of an auxin responsive gene, specifically at the root tip region by pseudomonad cyanogenesis. Additionally, pseudomonad cyanogenesis also affected other beneficial rhizospheric processes such as Bacillus subtilis colonization by biofilm formation on A. thaliana Col-0 roots. The effect of cyanogenesis on B. subtilis biofilm formation was further established by the down regulation of important B. subtilis biofilm operons epsA and yqxM. Our results show, the functional significance of pseudomonad cyanogenesis in regulating multitrophic rhizospheric interactions. PMID:18446201

  8. The Hertzsprung-Russell Diagram.

    ERIC Educational Resources Information Center

    Woodrow, Janice

    1991-01-01

    Describes a classroom use of the Hertzsprung-Russell diagram to infer not only the properties of a star but also the star's probable stage in evolution, life span, and age of the cluster in which it is located. (ZWH)

  9. Atemporal diagrams for quantum circuits

    SciTech Connect

    Griffiths, Robert B.; Wu Shengjun; Yu Li; Cohen, Scott M.

    2006-05-15

    A system of diagrams is introduced that allows the representation of various elements of a quantum circuit, including measurements, in a form which makes no reference to time (hence 'atemporal'). It can be used to relate quantum dynamical properties to those of entangled states (map-state duality), and suggests useful analogies, such as the inverse of an entangled ket. Diagrams clarify the role of channel kets, transition operators, dynamical operators (matrices), and Kraus rank for noisy quantum channels. Positive (semidefinite) operators are represented by diagrams with a symmetry that aids in understanding their connection with completely positive maps. The diagrams are used to analyze standard teleportation and dense coding, and for a careful study of unambiguous (conclusive) teleportation. A simple diagrammatic argument shows that a Kraus rank of 3 is impossible for a one-qubit channel modeled using a one-qubit environment in a mixed state.

  10. Exercising influence: distinct biotic interactions shape root microbiomes.

    PubMed

    Sloan, Sarah Stuart; Lebeis, Sarah L

    2015-08-01

    Root microbiomes are formed from diverse microbial soil settings with extraordinary consistency, suggesting both defined mechanisms of assembly and specific microbial activity. Recent improvements in sequencing technologies, data analysis techniques, and study design, allow definition of the microbiota within these intimate and important relationships with increasing accuracy. Comparing datasets provides powerful insights into the overlap of plant microbiomes, as well as the impacts of surrounding plants and microbes on root microbiomes and long-term soil conditioning. Here we address how recent studies tease apart the impact of various biotic interactions, including: plant-plant, plant-microbe, and microbe-microbe on root microbiome composition. PMID:26116973

  11. Exercising influence: distinct biotic interactions shape root microbiomes.

    PubMed

    Sloan, Sarah Stuart; Lebeis, Sarah L

    2015-08-01

    Root microbiomes are formed from diverse microbial soil settings with extraordinary consistency, suggesting both defined mechanisms of assembly and specific microbial activity. Recent improvements in sequencing technologies, data analysis techniques, and study design, allow definition of the microbiota within these intimate and important relationships with increasing accuracy. Comparing datasets provides powerful insights into the overlap of plant microbiomes, as well as the impacts of surrounding plants and microbes on root microbiomes and long-term soil conditioning. Here we address how recent studies tease apart the impact of various biotic interactions, including: plant-plant, plant-microbe, and microbe-microbe on root microbiome composition.

  12. The Influence of Context-Specific and Dispositional Achievement Goals on Children's Paired Collaborative Interaction

    ERIC Educational Resources Information Center

    Harris, Amanda; Yuill, Nicola; Luckin, Rosemary

    2008-01-01

    Background: Research has demonstrated that working collaboratively can have positive effects on children's learning. While key factors have been identified which influence the quality of these interactions, little research has addressed the influence of children's achievement goals on collaborative behaviour. Aims: This paper investigates the…

  13. Opinion dynamics on interacting networks: media competition and social influence.

    PubMed

    Quattrociocchi, Walter; Caldarelli, Guido; Scala, Antonio

    2014-01-01

    The inner dynamics of the multiple actors of the informations systems - i.e, T.V., newspapers, blogs, social network platforms, - play a fundamental role on the evolution of the public opinion. Coherently with the recent history of the information system (from few main stream media to the massive diffusion of socio-technical system), in this work we investigate how main stream media signed interaction might shape the opinion space. In particular we focus on how different size (in the number of media) and interaction patterns of the information system may affect collective debates and thus the opinions' distribution. We introduce a sophisticated computational model of opinion dynamics which accounts for the coexistence of media and gossip as separated mechanisms and for their feedback loops. The model accounts also for the effect of the media communication patterns by considering both the simple case where each medium mimics the behavior of the most successful one (to maximize the audience) and the case where there is polarization and thus competition among media memes. We show that plurality and competition within information sources lead to stable configurations where several and distant cultures coexist. PMID:24861995

  14. Influence of airfoil camber on convected gust interaction noise

    NASA Astrophysics Data System (ADS)

    Myers, M. R.; Kerschen, E. J.

    1986-07-01

    This paper investigates the effect of airfoil steady loading on the sound generated by the interaction of an airfoil with a convected disturbance. A previous theory, which included only the incidence angle contribution to the mean loading, is extended to include camber. The theory is based on a linearization of the Euler equations about a nonuniform, 0(1) Mach number subsonic mean flow. The discussion concentrates on the case of a slightly cambered airfoil at small incidence angle, interacting with a gust whose wavelength is short compared to the airfoil chord. The small parameter representing the amount of camber and incidence, and the large parameter representing the ratio of airfoil chord to disturbance wavelength, are utilized in a singular perturbation solution to the governing equations. Acoustic power calculations reveal that the amount of sound generated increases significantly with increased loading. More importantly, it is shown that the radiated acoustic power correlates very well with the strength of the mean flow around the leading edge.

  15. Opinion dynamics on interacting networks: media competition and social influence

    PubMed Central

    Quattrociocchi, Walter; Caldarelli, Guido; Scala, Antonio

    2014-01-01

    The inner dynamics of the multiple actors of the informations systems – i.e, T.V., newspapers, blogs, social network platforms, – play a fundamental role on the evolution of the public opinion. Coherently with the recent history of the information system (from few main stream media to the massive diffusion of socio-technical system), in this work we investigate how main stream media signed interaction might shape the opinion space. In particular we focus on how different size (in the number of media) and interaction patterns of the information system may affect collective debates and thus the opinions' distribution. We introduce a sophisticated computational model of opinion dynamics which accounts for the coexistence of media and gossip as separated mechanisms and for their feedback loops. The model accounts also for the effect of the media communication patterns by considering both the simple case where each medium mimics the behavior of the most successful one (to maximize the audience) and the case where there is polarization and thus competition among media memes. We show that plurality and competition within information sources lead to stable configurations where several and distant cultures coexist. PMID:24861995

  16. Opinion dynamics on interacting networks: media competition and social influence.

    PubMed

    Quattrociocchi, Walter; Caldarelli, Guido; Scala, Antonio

    2014-05-27

    The inner dynamics of the multiple actors of the informations systems - i.e, T.V., newspapers, blogs, social network platforms, - play a fundamental role on the evolution of the public opinion. Coherently with the recent history of the information system (from few main stream media to the massive diffusion of socio-technical system), in this work we investigate how main stream media signed interaction might shape the opinion space. In particular we focus on how different size (in the number of media) and interaction patterns of the information system may affect collective debates and thus the opinions' distribution. We introduce a sophisticated computational model of opinion dynamics which accounts for the coexistence of media and gossip as separated mechanisms and for their feedback loops. The model accounts also for the effect of the media communication patterns by considering both the simple case where each medium mimics the behavior of the most successful one (to maximize the audience) and the case where there is polarization and thus competition among media memes. We show that plurality and competition within information sources lead to stable configurations where several and distant cultures coexist.

  17. Opinion dynamics on interacting networks: media competition and social influence

    NASA Astrophysics Data System (ADS)

    Quattrociocchi, Walter; Caldarelli, Guido; Scala, Antonio

    2014-05-01

    The inner dynamics of the multiple actors of the informations systems - i.e, T.V., newspapers, blogs, social network platforms, - play a fundamental role on the evolution of the public opinion. Coherently with the recent history of the information system (from few main stream media to the massive diffusion of socio-technical system), in this work we investigate how main stream media signed interaction might shape the opinion space. In particular we focus on how different size (in the number of media) and interaction patterns of the information system may affect collective debates and thus the opinions' distribution. We introduce a sophisticated computational model of opinion dynamics which accounts for the coexistence of media and gossip as separated mechanisms and for their feedback loops. The model accounts also for the effect of the media communication patterns by considering both the simple case where each medium mimics the behavior of the most successful one (to maximize the audience) and the case where there is polarization and thus competition among media memes. We show that plurality and competition within information sources lead to stable configurations where several and distant cultures coexist.

  18. Interactive Television Instructors' Perceptions of Students' Nonverbal Responsiveness and Their Influence on Distance Teaching.

    ERIC Educational Resources Information Center

    Mottet, Timothy P.

    The objective of this study was to examine the relationships between interactive television instructors' perceptions of students' nonverbal responsiveness and the influence of these perceptions on distance teaching. The study yielded three general conclusions. First, interactive television instructors' perceptions of students' nonverbal…

  19. Interpersonal Interaction in Online Learning: Experienced Online Instructors' Perceptions of Influencing Factors

    ERIC Educational Resources Information Center

    York, Cindy S.; Richardson, Jennifer C.

    2012-01-01

    A multitude of factors influence interpersonal interaction between students and instructors in an online course. This study examines perceptions of six experienced online instructors to determine factors they believe increase interaction among their students and between the students and instructor of online courses. The end result is an inventory…

  20. Air-sea Interaction Influence on the MJO propagation

    NASA Astrophysics Data System (ADS)

    May, P. W.; Chen, S.; Doyle, J.; Flatau, M. K.; Schmidt, J. M.

    2012-12-01

    The Madden-Julian oscillation (MJO) is a multi-scale low frequency mode that influences the intraseasonal variability of weather across the globe. One of the outstanding forecast challenges is the large model errors in the MJO eastward propagation as it transitions from the Indian Ocean to the Maritime Continent. We will discuss the air-sea coupling impact on the MJO propagation using the Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS) running in an extended forecast mode on the second CINDY/DYNAMO MJO. Preliminary comparison with uncoupled forecast indicates the effect of the full ocean coupling is to damp the westward propagating modes and retrograde the eastward propagating mode. The impacts of these changes are examined through the analysis of the model sensitivity and satellite data.

  1. Beyond the dyad: do family interactions influence children's attachment representations in middle childhood?

    PubMed

    Dubois-Comtois, Karine; Moss, Ellen

    2008-12-01

    This study examines the influence of mother-child and family interactions on the development of child attachment representations in middle childhood for a sample of 49 families. Mother-child interactions were observed during a snacktime in a lab setting (Moss, Rousseau, Parent, St-Laurent, & Saintonge, 1998) when children were 5-6 years old. Three years later, children's attachment representations were assessed using a doll play narrative procedure (Solomon, George, & DeJong, 1995) in the lab setting. Within 6 months of the second lab visit, family interactions were filmed during mealtime and coded using the Mealtime Interaction Coding System (MICS; Dickstein, Hayden, Schiller, Seifer, & San Antonio, 1994). Results showed clear differences between attachment groups on quality of mother-child and family interaction with the secure/confident group showing highest and the disorganized/frightened group showing lowest quality interactions. Family interactions predicted children's attachment representations, after controlling variance explained by prior mother-child interactions.

  2. Some factors influencing cadmium-manganese interaction in adult rats

    SciTech Connect

    Gruden, N.; Matausic, S. )

    1989-07-01

    Recent data show that even a low dose of cadmium (20 {mu}g/day/rat) significantly suppresses manganese transduodenal transport when administered during a three-day period. The inhibitory effect of cadmium upon manganese absorption is enhanced by concurrently administered iron-fortified milk diet. This suggests that the (synergistic) action of cadmium and iron upon manganese and the competition between these (three) ions in the intestine depend on their relative concentrations and affinity for the binding sites within the intestinal mucosa. For this reason the authors considered it worthwhile examining whether this inhibitory effect of cadmium would be affected by simultaneously administered manganese-fortified milk. Since the absorption of heavy metals and, at the same time, the demand for manganese is higher in the young than in the old animals, they also studied how this interaction depends upon the animals' age and sex and whether it is the same in the whole small intestine.

  3. Failure Assessment Diagram for Brazed 304 Stainless Steel Joints

    NASA Technical Reports Server (NTRS)

    Flom, Yory

    2011-01-01

    Interaction equations were proposed earlier to predict failure in Albemet 162 brazed joints. Present study demonstrates that the same interaction equations can be used for lower bound estimate of the failure criterion in 304 stainless steel joints brazed with silver-based filler metals as well as for construction of the Failure Assessment Diagrams (FAD).

  4. Influence of receptor flexibility on intramolecular H-bonding interactions.

    PubMed

    Sun, Hongmei; Guo, Kai; Gan, Haifeng; Li, Xin; Hunter, Christopher A

    2015-08-01

    Atropisomers of a series of zinc tetraphenyl porphyrins were synthesized and used as supramolecular receptors. Rotation around the porphyrin-meso phenyl bonds is restricted by installing ortho-chlorine substituents on the phenyl groups. The chlorine substituents allowed chromatographic separation of atropisomers, which did not interconvert at room temperature. The porphyrin meso phenyl groups were also equipped with phenol groups, which led to the formation of intramolecular H-bonds when the zinc porphyrins were bound to pyridine ligands equipped with ester or amide side arms. Binding of the pyridine ligands with the conformationally locked chloroporphyrins was compared with the corresponding unsubstituted porphyrins, which are more flexible. The association constants of 150 zinc porphyrin-pyridine complexes were measured in two different solvents, toluene and 1,1,2,2-tetrachloroethane (TCE). These association constants were then used to construct 120 chemical double mutant cycles to quantify the influence of chlorine substitution on the free energy of intramolecular H-bonds formed between the phenol side arms of the porphyrins and the ester or amide side arms of the pyridine ligands. Conformational restriction leads to increases in the stability of some complexes and decreases in the stability of others with variations in the free energy contribution due to intramolecular H-bonding of -5 to +6 kJ mol(-1).

  5. Factors in client-clinician interaction that influence hearing aid adoption.

    PubMed

    Poost-Foroosh, Laya; Jennings, Mary Beth; Shaw, Lynn; Meston, Christine N; Cheesman, Margaret F

    2011-09-01

    The influence of client-clinician interactions has not been emphasized in hearing health care, despite the extensive evidence of the impact of the provider-patient interaction on health outcomes. The purpose of this study was to identify factors in the client-clinician interaction that may influence hearing aid adoption. Thirteen adults who had received a hearing aid recommendation within the previous 3 months and 10 audiologists participated in a study to generate, sort, and rate the importance of factors in client-clinician interaction that may influence the hearing aid purchase decision. A concept mapping approach was used to define meaningful clusters of factors. Quantitative analysis and qualitative interpretation of the statements resulted in eight concepts. The concepts in order of their importance are (a) Ensuring client comfort, (b) Understanding and meeting client needs, (c) Client-centered traits and actions, (d) Acknowledging client as an individual, (e) Imposing undue pressure and discomfort, (f) Conveying device information by clinician, (g) Supporting choices and shared decision making, and (h) Factors in client readiness. Two overarching themes of client-centered interaction and client empowerment were identified. Results highlight the influence of the client-clinician interaction in hearing aid adoption and suggest the possibility of improving hearing aid adoption by empowering clients through a client-centered interaction.

  6. Jupiter Torus Diagram

    NASA Technical Reports Server (NTRS)

    2003-01-01

    A cut-away schematic of Jupiter's space environment shows magnetically trapped radiation ions (in red), the neutral gas torus of the volcanic moon Io (green) and the newly discovered neutral gas torus of the moon Europa (blue). The white lines represent magnetic field lines.

    Energetic neutral atoms (ENA) are emitted from the Europa torus regions because of the interaction between the trapped ions and the neutral gases. The Magnetospheric Imaging Instrument on NASA's Cassini spacecraft imaged those energetic neutral atoms in early 2001 during Cassini's flyby of Jupiter. Energetic neutral atoms also come from Jupiter when radiation ions impinge onto Jupiter's upper atmosphere.

    Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages Cassini for NASA's Office of Space Science, Washington, D.C.

  7. Intraspecific genetic variation and competition interact to influence niche expansion

    PubMed Central

    Agashe, Deepa; Bolnick, Daniel I.

    2010-01-01

    Theory and empirical evidence show that intraspecific competition can drive selection favouring the use of novel resources (i.e. niche expansion). The evolutionary response to such selection depends on genetic variation for resource use. However, while genetic variation might facilitate niche expansion, genetically diverse groups may also experience weaker competition, reducing density-dependent selection on resource use. Therefore, genetic variation for fitness on different resources could directly facilitate, or indirectly retard, niche expansion. To test these alternatives, we factorially manipulated both the degree of genetic variation and population density in flour beetles (Tribolium castaneum) exposed to both novel and familiar food resources. Using stable carbon isotope analysis, we measured temporal change and individual variation in beetle diet across eight generations. Intraspecific competition and genetic variation acted on different components of niche evolution: competition facilitated niche expansion, while genetic variation increased individual variation in niche use. In addition, genetic variation and competition together facilitated niche expansion, but all these impacts were temporally variable. Thus, we show that the interaction between genetic variation and competition can also determine niche evolution at different time scales. PMID:20462902

  8. Automatically Assessing Graph-Based Diagrams

    ERIC Educational Resources Information Center

    Thomas, Pete; Smith, Neil; Waugh, Kevin

    2008-01-01

    To date there has been very little work on the machine understanding of imprecise diagrams, such as diagrams drawn by students in response to assessment questions. Imprecise diagrams exhibit faults such as missing, extraneous and incorrectly formed elements. The semantics of imprecise diagrams are difficult to determine. While there have been…

  9. How will biotic interactions influence climate change-induced range shifts?

    PubMed

    HilleRisLambers, Janneke; Harsch, Melanie A; Ettinger, Ailene K; Ford, Kevin R; Theobald, Elinore J

    2013-09-01

    Biotic interactions present a challenge in determining whether species distributions will track climate change. Interactions with competitors, consumers, mutualists, and facilitators can strongly influence local species distributions, but few studies assess how and whether these interactions will impede or accelerate climate change-induced range shifts. In this paper, we explore how ecologists might move forward on this question. We first outline the conditions under which biotic interactions can result in range shifts that proceed faster or slower than climate velocity and result in ecological surprises. Next, we use our own work to demonstrate that experimental studies documenting the strength of biotic interactions across large environmental gradients are a critical first step for understanding whether they will influence climate change-induced range shifts. Further progress could be made by integrating results from these studies into modeling frameworks to predict how or generalize when biotic interactions mediate how changing climates influence range shifts. Finally, we argue that many more case studies like those described here are needed to explore the importance of biotic interactions during climate change-induced range shifts.

  10. Universal jamming phase diagram in the hard-sphere limit.

    PubMed

    Haxton, Thomas K; Schmiedeberg, Michael; Liu, Andrea J

    2011-03-01

    We present a new formulation of the jamming phase diagram for a class of glass-forming fluids consisting of spheres interacting via finite-ranged repulsions at temperature T, packing fraction ϕ or pressure p, and applied shear stress Σ. We argue that the natural choice of axes for the phase diagram are the dimensionless quantities T/pσ³, pσ³/ε, and Σ/p, where T is the temperature, p is the pressure, Σ is the stress, σ is the sphere diameter, ε is the interaction energy scale, and m is the sphere mass. We demonstrate that the phase diagram is universal at low pσ³/ε; at low pressure, observables such as the relaxation time are insensitive to details of the interaction potential and collapse onto the values for hard spheres, provided the observables are nondimensionalized by the pressure. We determine the shape of the jamming surface in the jamming phase diagram, organize previous results in relation to the jamming phase diagram, and discuss the significance of various limits.

  11. Voronoi Diagrams and Spring Rain

    ERIC Educational Resources Information Center

    Perham, Arnold E.; Perham, Faustine L.

    2011-01-01

    The goal of this geometry project is to use Voronoi diagrams, a powerful modeling tool across disciplines, and the integration of technology to analyze spring rainfall from rain gauge data over a region. In their investigation, students use familiar equipment from their mathematical toolbox: triangles and other polygons, circumcenters and…

  12. Sound generation and upstream influence due to instability waves interacting with non-uniform mean flows

    NASA Technical Reports Server (NTRS)

    Goldstein, M. E.

    1984-01-01

    Attention is given to the sound produced by artificially excited, spatially growing instability waves on subsonic shear layers. Real flows that always diverge in the downstream direction allow sound to be produced by the interaction of the instability waves with the resulting streamwise variations of the flow. The upstream influence, or feedback, can interact with the splitter plate lip to produce a downstream-propagating instability wave that may under certain conditions be the same instability wave that originally generated the upstream influence. The present treatment is restricted to very low Mach number flows, so that compressibility effects can only become important over large distances.

  13. Influence of chaotic synchronization on mixing in the phase space of interacting systems

    NASA Astrophysics Data System (ADS)

    Astakhov, Sergey V.; Dvorak, Anton; Anishchenko, Vadim S.

    2013-03-01

    Using the concept of the relative metric entropy, we study the influence of the synchronization phenomenon on mixing rate in the phase space of deterministic and noisy chaotic systems. We show that transition to both complete and phase synchronization of chaos is accompanied by the decrease of the level of mixing induced by internal nonlinear mechanisms of interacting systems as well as by external noise influence. Therefore, the decrease of the mixing rate in the phase space of interacting systems may indicate transition to synchronization. The obtained results are important for time series analysis in various types of real noisy systems (e.g., biological, social, and financial systems).

  14. Cues Matter: Learning Assistants Influence Introductory Biology Student Interactions during Clicker-Question Discussions.

    PubMed

    Knight, Jennifer K; Wise, Sarah B; Rentsch, Jeremy; Furtak, Erin M

    2015-01-01

    The cues undergraduate biology instructors provide to students before discussions of clicker questions have previously been shown to influence student discussion. We further explored how student discussions were influenced by interactions with learning assistants (LAs, or peer coaches). We recorded and transcribed 140 clicker-question discussions in an introductory molecular biology course and coded them for features such as the use of reasoning and types of questions asked. Students who did not interact with LAs had discussions that were similar in most ways to students who did interact with LAs. When students interacted with LAs, the only significant changes in their discussions were the use of more questioning and more time spent in discussion. However, when individual LA-student interactions were examined within discussions, different LA prompts were found to generate specific student responses: question prompts promoted student use of reasoning, while students usually stopped their discussions when LAs explained reasons for answers. These results demonstrate that LA prompts directly influence student interactions during in-class discussions. Because clicker discussions can encourage student articulation of reasoning, instructors and LAs should focus on how to effectively implement questioning techniques rather than providing explanations. PMID:26590204

  15. Cues Matter: Learning Assistants Influence Introductory Biology Student Interactions during Clicker-Question Discussions

    PubMed Central

    Knight, Jennifer K.; Wise, Sarah B.; Rentsch, Jeremy; Furtak, Erin M.

    2015-01-01

    The cues undergraduate biology instructors provide to students before discussions of clicker questions have previously been shown to influence student discussion. We further explored how student discussions were influenced by interactions with learning assistants (LAs, or peer coaches). We recorded and transcribed 140 clicker-question discussions in an introductory molecular biology course and coded them for features such as the use of reasoning and types of questions asked. Students who did not interact with LAs had discussions that were similar in most ways to students who did interact with LAs. When students interacted with LAs, the only significant changes in their discussions were the use of more questioning and more time spent in discussion. However, when individual LA–student interactions were examined within discussions, different LA prompts were found to generate specific student responses: question prompts promoted student use of reasoning, while students usually stopped their discussions when LAs explained reasons for answers. These results demonstrate that LA prompts directly influence student interactions during in-class discussions. Because clicker discussions can encourage student articulation of reasoning, instructors and LAs should focus on how to effectively implement questioning techniques rather than providing explanations. PMID:26590204

  16. Influence of dipolar interaction on magnetic properties of ultrafine ferromagnetic particles

    PubMed

    Garcia-Otero; Porto; Rivas; Bunde

    2000-01-01

    We use Monte Carlo simulations to study the influence of dipolar interaction and polydispersity on the magnetic properties of single-domain ultrafine ferromagnetic particles. From the zero field cooling (ZFC)/field cooling (FC) simulations we observe that the blocking temperature T(B) clearly increases with increasing strength of interaction, but it is almost not effected by a broadening of the distribution of particle sizes. While the dependence of the ZFC/FC curves on interaction and cooling rate are reminiscent of a spin glass transition at T(B), the relaxational behavior of the magnetic moments below T(B) is not in accordance with the picture of cooperative freezing.

  17. White is green: new schematic diagrams

    NASA Astrophysics Data System (ADS)

    Glicksman, Hal

    2002-06-01

    Two new schematic diagrams are presented here that derive from the study of the value relationships of the primary colors of RGB computer and video color. The first diagram is a 'Truth Table' that presents true-false, on-off states of the three colors of RGB so that the colors are presented in the order of their brightness values. The second diagram is a triple Venn diagram based on the perception of color. This diagram is presented as an alternative to the Venn diagrams of additive and subtractive color usually used to explain color.

  18. Flow interaction based propagation model and bursty influence behavior analysis of Internet flows

    NASA Astrophysics Data System (ADS)

    Wu, Xiao-Yu; Gu, Ren-Tao; Ji, Yue-Feng

    2016-11-01

    QoS (quality of service) fluctuations caused by Internet bursty flows influence the user experience in the Internet, such as the increment of packet loss and transmission time. In this paper, we establish a mathematical model to study the influence propagation behavior of the bursty flow, which is helpful for developing a deep understanding of the network dynamics in the Internet complex system. To intuitively reflect the propagation process, a data flow interaction network with a hierarchical structure is constructed, where the neighbor order is proposed to indicate the neighborhood relationship between the bursty flow and other flows. The influence spreads from the bursty flow to each order of neighbors through flow interactions. As the influence spreads, the bursty flow has negative effects on the odd order neighbors and positive effects on the even order neighbors. The influence intensity of bursty flow decreases sharply between two adjacent orders and the decreasing degree can reach up to dozens of times in the experimental simulation. Moreover, the influence intensity increases significantly when network congestion situation becomes serious, especially for the 1st order neighbors. Network structural factors are considered to make a further study. Simulation results show that the physical network scale expansion can reduce the influence intensity of bursty flow by decreasing the flow distribution density. Furthermore, with the same network scale, the influence intensity in WS small-world networks is 38.18% and 18.40% lower than that in ER random networks and BA scale-free networks, respectively, due to a lower interaction probability between flows. These results indicate that the macro-structural changes such as network scales and styles will affect the inner propagation behaviors of the bursty flow.

  19. Transitioning Transfer Students: Interactive Factors that Influence First-Year Retention

    ERIC Educational Resources Information Center

    Luo, Mingchu; Williams, James E.; Vieweg, Bruce

    2007-01-01

    This study examined the diverse patterns of interactive factors that influence transfer students' first-year retention at a midsize four-year university. The population for this study consisted of five cohorts totaling 1,713 full-time, degree-seeking transfer students. Sequential sets of logistic regression analyses on blocks of variables were…

  20. Interaction in Instrumental Learning: The Influence of Interpersonal Dynamics on Parents

    ERIC Educational Resources Information Center

    Creech, Andrea; Hallam, Susan

    2009-01-01

    The research reported here forms part of a UK study that investigated the impact of interpersonal interaction on teaching and learning outcomes, in the context of learning a musical instrument. This article presents the findings relating to parents, exploring how parental involvement, self-efficacy and personal satisfaction were influenced by…

  1. The Influence of Interactive Context on Prelinguistic Vocalizations and Maternal Responses

    ERIC Educational Resources Information Center

    Gros-Louis, Julie; West, Meredith J.; King, Andrew P.

    2016-01-01

    Many studies have documented influences of maternal responsiveness on cognitive and language development. Given the bidirectionality of interactions in caregiver-infant dyads, it is important to understand how infant behavior elicits variable responses. Prior studies have shown that mothers respond differentially to features of prelinguistic…

  2. The Influence of Learner Characteristics on Satisfaction with Interactive Televised Courses in Florida Community Colleges.

    ERIC Educational Resources Information Center

    Bower, Beverly L.; Kamata, Akihito; Smith, Kathleen Shea

    This report describes a pilot project designed to explore the influence of particular personality and demographic characteristics on community college student satisfaction with distance learning, specifically interactive telecommunications (ITV) courses. The study used the Telecourse Evaluation Questionnaire (TEQ) and the Sixteen Personality…

  3. The influence of third-order interactions on the density profile of associating hard spheres

    NASA Astrophysics Data System (ADS)

    Henderson, D.; Sokolowski, S.; Zagorski, R.; Trokhymchuk, A.

    Canonical ensemble Monte Carlo simulations and the non-uniform Percus-Yevick (NPY) equation for the local density are used to study the influence of surface mediated thirdorder interactions on the adsorption of associating hard spheres on a hard wall. A comparison of the NPY density profiles with the computer simulations data indicates that this approximation predicts the fluid structure reasonably well.

  4. Attentional Engagement in Infancy: The Interactive Influence of Attentional Inertia and Attentional State

    ERIC Educational Resources Information Center

    Oakes, Lisa M.; Ross-Sheehy, Shannon; Kannass, Kathleen N.

    2004-01-01

    We evaluated the interactive influences of attentional state and attentional inertia on infants' level of attentional engagement. We assessed infants' distraction latencies longitudinally at 6.5 and 9 months as they explored toys, and we coded both their attentional state (focused vs. casual) and how long they had been looking at the toy at each…

  5. Support Services and Learning Styles Influencing Interaction in Asynchronous Online Discussions

    ERIC Educational Resources Information Center

    Kucuk, M.; Genc-Kumtepe, E.; Tasci, D.

    2010-01-01

    This paper reports a case of online classes from the English Language Teaching Programme at Anadolu University, Turkey. The study used an explanatory case oriented research design that assisted to examine relations between students' learning styles and factors influencing students' participation in asynchronous interactions in online courses. The…

  6. Individual Variation in Agrammatism: A Single Case Study of the Influence of Interaction

    ERIC Educational Resources Information Center

    Beeke, Suzanne; Wilkinson, Ray; Maxim, Jane

    2007-01-01

    Background: Agrammatic speech can manifest in different ways in the same speaker if task demands change. Individual variation is considered to reflect adaptation, driven by psycholinguistic factors such as underlying deficit. Recently, qualitative investigations have begun to show ways in which conversational interaction can influence the form of…

  7. Influence of Structure and Interaction on Student Achievement and Satisfaction in Web-Based Distance Learning

    ERIC Educational Resources Information Center

    Lee, Hye-Jung; Rha, Ilju

    2009-01-01

    This study examines the influence of instructional design and management style on student achievement and satisfaction in a web-based distance learning environment. From the literature review, two major instructional design and management styles in web-based distance education were conceptualized as structure and interpersonal interaction. To…

  8. Interacting with a Computer-Simulated Pet: Factors Influencing Children's Humane Attitudes and Empathy

    ERIC Educational Resources Information Center

    Tsai, Yueh-Feng; Kaufman, David

    2014-01-01

    Previous research by Tsai and Kaufman (2010a, 2010b) has suggested that computer-simulated virtual pet dogs can be used as a potential medium to enhance children's development of empathy and humane attitudes toward animals. To gain a deeper understanding of how and why interacting with a virtual pet dog might influence children's social and…

  9. Interactive influences of bioactive trace metals on biological production in oceanic waters

    SciTech Connect

    Bruland, K.W.; Donat, J.R.; Hutchins, D.A. )

    1991-12-01

    The authors present an overview of the oceanic chemistries of the bioactive trace metals, Mn, Fe, Co, Ni, Cu, and Zn; the authors combine field data with results from laboratory phytoplankton culture-trace metal studies and speculate on the potential influences of these trace metals on oceanic plankton production and species composition. Most field studies have focused on the effects of single metals. However, they propose that synergistic and antagonistic interactions between multiple trace metals could be very important in the oceans. Trace metal antagonisms that may prove particularly important are those between Cu and the potential biolimiting metals Fe, Mn, and Zn. These antagonistic interactions could have the greatest influence on biological productivity in areas of the open ocean isolated from terrestrial inputs, such as the remote high nutrient regions of the Pacific and Antarctic Oceans. The emerging picture of trace metal-biota interactions in these oceanic areas is one in which biology strongly influences distribution and chemical speciation of all these bioactive trace metals. It also seems likely that many of these bioactive trace metals and their speciation may influence levels of primary productivity, species composition, and trophic structure. Future investigations should give more complete consideration to the interactive effects of biologically important trace metals.

  10. Modeling the Influence of Interaction Layer Formation on Thermal Conductivity of U–Mo Dispersion Fuel

    SciTech Connect

    Burkes, Douglas; Casella, Andrew M.; Huber, Tanja K.

    2015-01-01

    The Global Threat Reduction Initiative Program continues to develop existing and new plate- and rod-type research and test reactor fuels with maximum attainable uranium loadings capable of potentially converting a number of the world’s remaining high-enriched uranium fueled reactors to low-enriched uranium fuel. Currently, the program is focused on assisting with the development and qualification of an even higher density fuel type consisting of a uranium-molybdenum (U-Mo) alloy dispersed in an aluminum matrix. Thermal conductivity is an important consideration in determining the operational temperature of the fuel plate and can be influenced by interaction layer formation between the fuel and matrix, porosity that forms during fabrication of the fuel plates, and upon the concentration of the dispersed phase within the matrix. This paper develops and validates a simple model to study the influence of interaction layer formation and conductivity, fuel particle size, and volume fraction of fuel dispersed in the matrix on the effective conductivity of the composite. The model shows excellent agreement with results previously presented in the literature. In particular, the thermal conductivity of the interaction layer does not appear to be important in determining the overall conductivity of the composite, while formation of the interaction layer and subsequent consumption of the matrix reveals a rather significant effect. The effective thermal conductivity of the composite can be influenced by the fuel particle distribution by minimizing interaction layer formation and preserving the higher thermal conductivity matrix.

  11. How parental dietary behavior and food parenting practices affect children's dietary behavior. Interacting sources of influence?

    PubMed

    Larsen, Junilla K; Hermans, Roel C J; Sleddens, Ester F C; Engels, Rutger C M E; Fisher, Jennifer O; Kremers, Stef P J

    2015-06-01

    Until now, the literatures on the effects of food parenting practices and parents' own dietary behavior on children's dietary behavior have largely been independent from one another. Integrating findings across these areas could provide insight on simultaneous and interacting influences on children's food intake. In this narrative review, we provide a conceptual model that bridges the gap between both literatures and consists of three main hypotheses. First, parental dietary behavior and food parenting practices are important interactive sources of influence on children's dietary behavior and Body Mass Index (BMI). Second, parental influences are importantly mediated by changes in the child's home food environment. Third, parenting context (i.e., parenting styles and differential parental treatment) moderates effects of food parenting practices, whereas child characteristics (i.e., temperament and appetitive traits) mainly moderate effects of the home food environment. Future studies testing (parts of) this conceptual model are needed to inform effective parent-child overweight preventive interventions.

  12. Pharmacists’ Perceptions of the Influence of Interactions with the Pharmaceutical Industry on Clinical Decision-Making

    PubMed Central

    Tejani, Aaron M; Loewen, Peter; Bachand, Richard; Harder, Curtis K

    2015-01-01

    Background: There is a paucity of literature examining the perceptions of Canadian pharmacists toward drug promotion by the pharmaceutical industry and pharmacist–industry interactions. Objectives: To determine whether hospital pharmacists perceive their interactions with the pharmaceutical industry as influencing their clinical decision-making or that of their colleagues and whether hospital pharmacists perceive that interactions with the pharmaceutical industry create a conflict of interest. Methods: A cross-sectional survey of the complete sample of hospital pharmacists practising in 3 large health authorities in a single Canadian province was conducted from February to April 2010. Results: A total of 224 responses were received from the approximately 480 pharmacists in the target health authorities (response rate approximately 47%). Fifty-eight percent of respondents (127/218) did not believe that information received at industry-sponsored events influenced their clinical decision-making. Most (142/163 [87%]) disagreed that small gifts influenced their clinical decision-making, whereas responses were divided for large gifts. Respondents were also divided on the issue of whether their interactions created conflicts of interest, with most of those who had received gifts agreeing that large gifts would create a conflict of interest (134/163 [82%]) whereas small gifts would not (100/163 [61%]). There were positive correlations between respondents’ beliefs about their own susceptibility to influence from sponsored events or receipt of small or large gifts and the susceptibility of others, but 22% of respondents (28/127) expressed a different perception about sponsored events, all believing themselves to be less influenced than their colleagues. Only 6% (4/64) of those who received large gifts and 4% (5/142) of those who received small gifts and felt they were not influenced by these gifts reported that it was likely others would be influenced by the receipt of

  13. Hero's journey in bifurcation diagram

    NASA Astrophysics Data System (ADS)

    Monteiro, L. H. A.; Mustaro, P. N.

    2012-06-01

    The hero's journey is a narrative structure identified by several authors in comparative studies on folklore and mythology. This storytelling template presents the stages of inner metamorphosis undergone by the protagonist after being called to an adventure. In a simplified version, this journey is divided into three acts separated by two crucial moments. Here we propose a discrete-time dynamical system for representing the protagonist's evolution. The suffering along the journey is taken as the control parameter of this system. The bifurcation diagram exhibits stationary, periodic and chaotic behaviors. In this diagram, there are transition from fixed point to chaos and transition from limit cycle to fixed point. We found that the values of the control parameter corresponding to these two transitions are in quantitative agreement with the two critical moments of the three-act hero's journey identified in 10 movies appearing in the list of the 200 worldwide highest-grossing films.

  14. Quantum Dimer Model: Phase Diagrams

    NASA Astrophysics Data System (ADS)

    Goldstein, Garry; Chamon, Claudio; Castelnovo, Claudio

    We present new theoretical analysis of the Quantum Dimer Model. We study dimer models on square, cubic and triangular lattices and we reproduce their phase diagrams (which were previously known only numerically). We show that there are several types of dimer liquids and solids. We present preliminary analysis of several other models including doped dimers and planar spin ice, and some results on the Kagome and hexagonal lattices.

  15. Introducing the Circular Flow Diagram to Business Students

    ERIC Educational Resources Information Center

    Daraban, Bogdan

    2010-01-01

    The circular flow of income diagram is a simplified representation of the functioning of a free-market economic system. It illustrates how businesses interact with the other economic participants within the key macroeconomic markets that coordinate the flow of income through the national economy. Therefore, it can provide students of business with…

  16. Analysing Collisions Using Minkowski Diagrams in Momentum Space

    ERIC Educational Resources Information Center

    Bokor, Nandor

    2011-01-01

    Momentum space and Minkowski diagrams are powerful tools for interpreting and analysing relativistic collisions in one or two spatial dimensions. All relevant quantities that characterize a collision, including the mass, velocity, momentum and energy of the interacting particles, both before and after collision, can be directly seen from a single…

  17. INCONEL 718: A solidification diagram

    NASA Astrophysics Data System (ADS)

    Knorovsky, G. A.; Cieslak, M. J.; Headley, T. J.; Romig, A. D.; Hammetter, W. F.

    1989-10-01

    As part of a program studying weldability of Ni-base superalloys, results of an integrated analytical approach are used to generate a constitution diagram for INCONEL 718* in the temperature range associated with solidification. Differential thermal analysis of wrought material and optical and scanning electron microscopy, electron probe microanalysis, and analytical electron microscopy of gas tungsten arc welds are used in conjunction with solidification theory to generate data points for this diagram. The important features of the diagram are an austenite (γ)/Laves phase eutectic which occurs at ≈19.1 wt pct Nb between austenite containing ≈9.3 wt pct Nb and a Laves phase which contains ≈22.4 wt pct Nb. The distribution coefficient for Nb was found to be ≈0.5. The solidification sequence of INCONEL 718 was found to be (1) proeutectic γ, followed by (2) a γ/NbC eutectic at ≈1250°C, followed by (3) continued γ solidification, followed by (4) a γ/Laves phase eutectic at ≈1200°C. An estimate of the volume fraction eutectic is made using the Scheil solidification model, and the fraction of each phase in the eutectic is calculated via the lever rule. These are compared with experimentally determined values and found to be in good agreement.

  18. Causal diagrams in systems epidemiology

    PubMed Central

    2012-01-01

    Methods of diagrammatic modelling have been greatly developed in the past two decades. Outside the context of infectious diseases, systematic use of diagrams in epidemiology has been mainly confined to the analysis of a single link: that between a disease outcome and its proximal determinant(s). Transmitted causes ("causes of causes") tend not to be systematically analysed. The infectious disease epidemiology modelling tradition models the human population in its environment, typically with the exposure-health relationship and the determinants of exposure being considered at individual and group/ecological levels, respectively. Some properties of the resulting systems are quite general, and are seen in unrelated contexts such as biochemical pathways. Confining analysis to a single link misses the opportunity to discover such properties. The structure of a causal diagram is derived from knowledge about how the world works, as well as from statistical evidence. A single diagram can be used to characterise a whole research area, not just a single analysis - although this depends on the degree of consistency of the causal relationships between different populations - and can therefore be used to integrate multiple datasets. Additional advantages of system-wide models include: the use of instrumental variables - now emerging as an important technique in epidemiology in the context of mendelian randomisation, but under-used in the exploitation of "natural experiments"; the explicit use of change models, which have advantages with respect to inferring causation; and in the detection and elucidation of feedback. PMID:22429606

  19. How does human-induced environmental change influence host-parasite interactions?

    PubMed

    Budria, Alexandre; Candolin, Ulrika

    2014-04-01

    Host-parasite interactions are an integral part of ecosystems that influence both ecological and evolutionary processes. Humans are currently altering environments the world over, often with drastic consequences for host-parasite interactions and the prevalence of parasites. The mechanisms behind the changes are, however, poorly known. Here, we explain how host-parasite interactions depend on two crucial steps--encounter rate and host-parasite compatibility--and how human activities are altering them and thereby host-parasite interactions. By drawing on examples from the literature, we show that changes in the two steps depend on the influence of human activities on a range of factors, such as the density and diversity of hosts and parasites, the search strategy of the parasite, and the avoidance strategy of the host. Thus, to unravel the mechanisms behind human-induced changes in host-parasite interactions, we have to consider the characteristics of all three parts of the interaction: the host, the parasite and the environment. More attention should now be directed to unfold these mechanisms, focusing on effects of environmental change on the factors that determine encounter rate and compatibility. We end with identifying several areas in urgent need of more investigations.

  20. Size Dependent Phase Diagrams of Nickel-Carbon Nanoparticles

    NASA Astrophysics Data System (ADS)

    Magnin, Y.; Zappelli, A.; Amara, H.; Ducastelle, F.; Bichara, C.

    2015-11-01

    The carbon rich phase diagrams of nickel-carbon nanoparticles, relevant to catalysis and catalytic chemical vapor deposition synthesis of carbon nanotubes, are calculated for system sizes up to about 3 nm (807 Ni atoms). A tight binding model for interatomic interactions drives the grand canonical Monte Carlo simulations used to locate solid, core shell and liquid stability domains, as a function of size, temperature, and carbon chemical potential or concentration. Melting is favored by carbon incorporation from the nanoparticle surface, resulting in a strong relative lowering of the eutectic temperature and a phase diagram topology different from the bulk one. This should lead to a better understanding of the nanotube growth mechanisms.

  1. Differential Effectiveness of Two Science Diagram Types.

    ERIC Educational Resources Information Center

    Holliday, William G.

    Reported is an Aptitude Treatment Instruction (ATI) Study designed to evaluate the aptitude of verbal comprehension in terms of two unitary complex science diagram types: a single complex block word diagram and a single complex picture word diagram.. ATI theory and research indicate that different effective instructional treatments tend to help…

  2. The Importance of Design in Learning from Node-Link Diagrams

    ERIC Educational Resources Information Center

    van Amelsvoort, Marije; van der Meij, Jan; Anjewierden, Anjo; van der Meij, Hans

    2013-01-01

    Diagrams organize by location. They give spatial cues for finding and recognizing information and for making inferences. In education, diagrams are often used to help students understand and recall information. This study assessed the influence of perceptual cues on reading behavior and subsequent retention. Eighty-two participants were assigned…

  3. Interpretation of the Hubble diagram in a nonhomogeneous universe

    NASA Astrophysics Data System (ADS)

    Fleury, Pierre; Dupuy, Hélène; Uzan, Jean-Philippe

    2013-06-01

    In the standard cosmological framework, the Hubble diagram is interpreted by assuming that the light emitted by standard candles propagates in a spatially homogeneous and isotropic spacetime. However, the light from “point sources”—such as supernovae—probes the Universe on scales where the homogeneity principle is no longer valid. Inhomogeneities are expected to induce a bias and a dispersion of the Hubble diagram. This is investigated by considering a Swiss-cheese cosmological model, which (1) is an exact solution of the Einstein field equations, (2) is strongly inhomogeneous on small scales, but (3) has the same expansion history as a strictly homogeneous and isotropic universe. By simulating Hubble diagrams in such models, we quantify the influence of inhomogeneities on the measurement of the cosmological parameters. Though significant in general, the effects reduce drastically for a universe dominated by the cosmological constant.

  4. An Instructional Strategy to Introduce Pedagogical Content Knowledge Using Venn Diagrams

    ERIC Educational Resources Information Center

    Otto, Charlotte A.; Everett, Susan A.

    2013-01-01

    This paper describes the use of a three-circle Venn diagram as a vehicle for introducing pre-service elementary teachers to pedagogical content knowledge (PCK). Each circle of the diagram represents pedagogy, content and context individually. The overlap of any two circles represents the interaction between the circles. For example, the overlap of…

  5. The Effect of Social Network Diagrams on a Virtual Network of Practice: A Korean Case

    ERIC Educational Resources Information Center

    Jo, Il-Hyun

    2009-01-01

    This study investigates the effect of the presentation of social network diagrams on virtual team members' interaction behavior via e-mail. E-mail transaction data from 22 software developers in a Korean IT company was analyzed and depicted as diagrams by social network analysis (SNA), and presented to the members as an intervention. Results…

  6. Phase diagram of a model of the protein amelogenin.

    PubMed

    Haaga, Jason; Pemberton, Elizabeth; Gunton, J D; Rickman, J M

    2016-08-28

    There has been considerable recent interest in the self-assembly and phase behavior of models of colloidal and protein particles with anisotropic interactions. One example of particular interest is amelogenin, an important protein involved in the formation of dental enamel. Amelogenin is primarily hydrophobic with a 25-residue charged C-terminus tail. This protein undergoes a hierarchical assembly process that is crucial to mineral deposition, and experimental work has demonstrated that the deletion of the C-terminus tail prevents this self-assembly. A simplified model of amelogenin has been proposed in which the protein is treated as a hydrophobic sphere, interacting via the Asakura-Oosawa (AO) potential, with a tethered point charge on its surface. In this paper, we examine the effect of the Coulomb interaction between the point charges in altering the phase diagram of the AO model. For the parameter case specific to amelogenin, we find that the previous in vitro experimental and model conditions correspond to the system being near the low-density edge of the metastable region of the phase diagram. Our study illustrates more generally the importance of understanding the phase diagram for proteins, in that the kinetic pathway for self-assembly and the resulting aggregate morphology depends on the location of the initial state in the phase diagram. PMID:27586954

  7. Phase diagram of a model of the protein amelogenin

    NASA Astrophysics Data System (ADS)

    Haaga, Jason; Pemberton, Elizabeth; Gunton, J. D.; Rickman, J. M.

    2016-08-01

    There has been considerable recent interest in the self-assembly and phase behavior of models of colloidal and protein particles with anisotropic interactions. One example of particular interest is amelogenin, an important protein involved in the formation of dental enamel. Amelogenin is primarily hydrophobic with a 25-residue charged C-terminus tail. This protein undergoes a hierarchical assembly process that is crucial to mineral deposition, and experimental work has demonstrated that the deletion of the C-terminus tail prevents this self-assembly. A simplified model of amelogenin has been proposed in which the protein is treated as a hydrophobic sphere, interacting via the Asakura-Oosawa (AO) potential, with a tethered point charge on its surface. In this paper, we examine the effect of the Coulomb interaction between the point charges in altering the phase diagram of the AO model. For the parameter case specific to amelogenin, we find that the previous in vitro experimental and model conditions correspond to the system being near the low-density edge of the metastable region of the phase diagram. Our study illustrates more generally the importance of understanding the phase diagram for proteins, in that the kinetic pathway for self-assembly and the resulting aggregate morphology depends on the location of the initial state in the phase diagram.

  8. Diagram, a Learning Environment for Initiation to Object-Oriented Modeling with UML Class Diagrams

    ERIC Educational Resources Information Center

    Py, Dominique; Auxepaules, Ludovic; Alonso, Mathilde

    2013-01-01

    This paper presents Diagram, a learning environment for object-oriented modelling (OOM) with UML class diagrams. Diagram an open environment, in which the teacher can add new exercises without constraints on the vocabulary or the size of the diagram. The interface includes methodological help, encourages self-correcting and self-monitoring, and…

  9. Phase diagrams of bosonic ABn chains

    NASA Astrophysics Data System (ADS)

    Cruz, G. J.; Franco, R.; Silva-Valencia, J.

    2016-04-01

    The A B N - 1 chain is a system that consists of repeating a unit cell with N sites where between the A and B sites there is an energy difference of λ. We considered bosons in these special lattices and took into account the kinetic energy, the local two-body interaction, and the inhomogenous local energy in the Hamiltonian. We found the charge density wave (CDW) and superfluid and Mott insulator phases, and constructed the phase diagram for N = 2 and 3 at the thermodynamic limit. The system exhibited insulator phases for densities ρ = α/ N, with α being an integer. We obtained that superfluid regions separate the insulator phases for densities larger than one. For any N value, we found that for integer densities ρ, the system exhibits ρ + 1 insulator phases, a Mott insulator phase, and ρ CDW phases. For non-integer densities larger than one, several CDW phases appear.

  10. [The influences of interaction during online gaming on sociability and aggression in real life].

    PubMed

    Fuji, Kei; Yoshida, Fujio

    2010-02-01

    This study examined the influences of online gaming on sociability and aggression in real life. It was hypothesized that the effects of online gaming would differ depending on the interaction style of the online-gamers. Online-gamers in Japan (n = 1 477) were asked to respond to questionnaires that measured interaction style during online gaming, the effects of sociability and aggression, as well as social and individual orientation in real life. Factor analysis of the scores for interaction style extracted five factors. Covariance structure analysis indicated that sociable interactions such as "Broadening relations" and "Feeling of belonging" promoted sociability in real life. In addition, "Release from daily hassles" promoted sociability and decreased aggression. In contrast, non-sociable and aggressive interactions decreased sociability and increased aggression. The results also suggested that a social orientation in real life promoted sociable interactions during game playing, while an individual orientation promoted non-sociable and aggressive interactions. These results supported the hypotheses and suggested that online gaming resulted in positive outcomes for those who are socially, but negative outcomes for those who are not.

  11. Conflict and expectancies interact to predict sexual behavior under the influence among gay and bisexual men

    PubMed Central

    Wells, Brooke E; Starks, Tyrel J; Parsons, Jeffrey T; Golub, Sarit

    2013-01-01

    As the mechanisms of the associations between substance use and risky sex remain unclear, this study investigates the interactive roles of conflicts about casual sex and condom use and expectancies of the sexual effects of substances in those associations among gay men. Conflict interacted with expectancies to predict sexual behavior under the influence; low casual sex conflict coupled with high expectancies predicted the highest number of casual partners, and high condom use conflict and high expectancies predicted the highest number of unprotected sex acts. Results have implications for intervention efforts that aim to improve sexual decision-making and reduce sexual expectancies. PMID:23584507

  12. Conflict and expectancies interact to predict sexual behavior under the influence among gay and bisexual men.

    PubMed

    Wells, Brooke E; Starks, Tyrel J; Parsons, Jeffrey T; Golub, Sarit

    2014-07-01

    As the mechanisms of the associations between substance use and risky sex remain unclear, this study investigates the interactive roles of conflicts about casual sex and condom use and expectancies of the sexual effects of substances in those associations among gay men. Conflict interacted with expectancies to predict sexual behavior under the influence; low casual sex conflict coupled with high expectancies predicted the highest number of casual partners, and high condom use conflict and high expectancies predicted the highest number of unprotected sex acts. Results have implications for intervention efforts that aim to improve sexual decision-making and reduce sexual expectancies.

  13. The influence of variations in Jupiter's plasma environment on the Europa interaction

    NASA Astrophysics Data System (ADS)

    Westlake, J. H.; Case, A. W.; Jia, X.; Kasper, J. C.; Khurana, K. K.; Kivelson, M.; McNutt, R. L., Jr.; Paty, C. S.; Rymer, A. M.; Saur, J.; Slavin, J. A.; Smith, H. T.; Stevens, M. L.

    2014-12-01

    We present a multidisciplinary study of the influence of variations in Jupiter's corotational plasma environment on the details of the Europa interaction and the production of Europa's sputtered atmosphere. We build upon the measurements of the Voyager and Galileo spacecraft with updated models of the Jovian plasma environment and its interaction with Europa. We specifically discuss how plasma perturbations affect the accuracy with which Europa's induction signature can be extracted from measurements and the resulting fidelity of any quantities obtained related to ocean depth and salinity.

  14. Origin and use of crystallization phase diagrams.

    PubMed

    Rupp, Bernhard

    2015-03-01

    Crystallization phase diagrams are frequently used to conceptualize the phase relations and also the processes taking place during the crystallization of macromolecules. While a great deal of freedom is given in crystallization phase diagrams owing to a lack of specific knowledge about the actual phase boundaries and phase equilibria, crucial fundamental features of phase diagrams can be derived from thermodynamic first principles. Consequently, there are limits to what can be reasonably displayed in a phase diagram, and imagination may start to conflict with thermodynamic realities. Here, the commonly used `crystallization phase diagrams' are derived from thermodynamic excess properties and their limitations and appropriate use is discussed.

  15. Expression of Superparamagnetic Particles on FORC Diagrams

    NASA Astrophysics Data System (ADS)

    Hirt, A. M.; Kumari, M.; Crippa, F.; Petri-Fink, A.

    2015-12-01

    Identification of superparamagnetic (SP) particles in natural materials provides information on processes that lead to the new formation or dissolution of iron oxides. SP particles express themselves on first-order reversal curve (FORC) diagrams as a distribution centered near the origin of the diagram. Pike et al. (2001, GJI, 145, 721) demonstrated that thermal relaxation produces an upward shift in the FORC distribution, and attributed this to a pause encountered at each reversal field. In this study we examine the relationship between this upward shift and particles size on two sets of synthetic iron oxide nanoparticles. One set of coated magnetite particles have well-constrained particles size with 9, 16 and 20 nm as their diameter. A second set from the FeraSpin™ Series, consisting of FeraSpinXS, M and XL, were evaluated. Rock magnetic experiments indicate that the first set of samples is exclusively magnetite, whereas the FeraSpin samples contain predominantly magnetite with some degree of oxidation. Samples from both sets show that the upward shift of the FORC distribution at the origin increases with decreasing particle size. The amount of shift in the FeraSpin series is less when compared to the samples from the first set. This is attributed to the effect of interaction that counteracts the effect of thermal relaxation behavior of the SP particles. The FeraSpin series also shows a broader FORC distribution on the vertical axis that appears to be related to non-saturation of the hysteresis curve at maximum applied field. This non-saturation behavior can be due to spins of very fine particles or oxidation to hematite. AC susceptibility at low temperature indicates that particle interaction may affect the effective magnetic particle size. Our results suggest that the FORC distribution in pure SP particle systems provides information on the particle size distribution or oxidation, which can be further evaluated with low temperature techniques.

  16. Voronoi Diagrams Without Bounding Boxes

    NASA Astrophysics Data System (ADS)

    Sang, E. T. K.

    2015-10-01

    We present a technique for presenting geographic data in Voronoi diagrams without having to specify a bounding box. The method restricts Voronoi cells to points within a user-defined distance of the data points. The mathematical foundation of the approach is presented as well. The cell clipping method is particularly useful for presenting geographic data that is spread in an irregular way over a map, as for example the Dutch dialect data displayed in Figure 2. The automatic generation of reasonable cell boundaries also makes redundant a frequently used solution to this problem that requires data owners to specify region boundaries, as in Goebl (2010) and Nerbonne et al (2011).

  17. Influences and interactions of inundation, peat, and snow on active layer thickness

    DOE PAGESBeta

    Atchley, Adam L.; Coon, Ethan T.; Painter, Scott L.; Harp, Dylan R.; Wilson, Cathy J.

    2016-05-18

    The effect of three environmental conditions: 1) thickness of organic soil, 2) snow depth, and 3) soil moisture content or water table height above and below the soil surface, on active layer thickness (ALT) are investigated using an ensemble of 1D thermal hydrology models. Sensitivity analyses of the ensemble exposed the isolated influence of each environmental condition on ALT and their multivariate interactions. The primary and interactive influences are illustrated in the form of color maps of ALT change. Results show that organic layer acts as a strong insulator, and its thickness is the dominant control of ALT, but themore » strength of the effect of organic layer thickness is dependent on the saturation state. Snow depth, subsurface saturation, and ponded water depth are strongly codependent and positively correlated to ALT.« less

  18. Vulnerabilities, Influences and Interaction Paths: Failure Data for Integrated System Risk Analysis

    NASA Technical Reports Server (NTRS)

    Malin, Jane T.; Fleming, Land

    2006-01-01

    We describe graph-based analysis methods for identifying and analyzing cross-subsystem interaction risks from subsystem connectivity information. By discovering external and remote influences that would be otherwise unexpected, these methods can support better communication among subsystem designers at points of potential conflict and to support design of more dependable and diagnosable systems. These methods identify hazard causes that can impact vulnerable functions or entities if propagated across interaction paths from the hazard source to the vulnerable target. The analysis can also assess combined impacts of And-Or trees of disabling influences. The analysis can use ratings of hazards and vulnerabilities to calculate cumulative measures of the severity and importance. Identification of cross-subsystem hazard-vulnerability pairs and propagation paths across subsystems will increase coverage of hazard and risk analysis and can indicate risk control and protection strategies.

  19. Parents' Metacognitive Knowledge: Influences on Parent-Child Interactions in a Science Museum Setting

    NASA Astrophysics Data System (ADS)

    Thomas, Gregory P.; Anderson, David

    2013-06-01

    Despite science learning in settings such as science museums being recognized as important and given increasing attention in science education circles, the investigation of parents' and their children's metacognition in such settings is still in its infancy. This is despite an individual's metacognition being acknowledged as an important influence on their learning within and across contexts. This research investigated parents' metacognitive procedural and conditional knowledge, a key element of their metacognition, related to (a) what they knew about how they and their children thought and learned, and (b) whether this metacognitive knowledge influenced their interactions with their children during their interaction with a moderately complex simulation in a science museum. Parents reported metacognitive procedural and conditional knowledge regarding their own and their children's thinking and learning processes. Further, parents were aware that this metacognitive knowledge influenced their interactions with their children, seeing this as appropriate pedagogical action for them within the context of the particular exhibit and its task requirements at the science museum, and for the child involved. These findings have implications for exhibit and activity development within science museum settings.

  20. Microbe-host interactions: Influence of the gut microbiota on the enteric nervous system.

    PubMed

    Hyland, Niall P; Cryan, John F

    2016-09-15

    The enteric nervous system (ENS), considered a separate branch of the autonomic nervous system, is located throughout the length of the gastrointestinal (GI) tract as a series of interconnected ganglionated plexi. Given the proximity of the intestinal microbiota to the ENS, it is perhaps not surprising that the gut microbiota can influence its development and function. However, these interactions are complex and may be either direct or indirect, often involving signalling initiated by microbe-derived components, metabolites or host-derived intermediaries which subsequently affect enteric nerve excitability and GI function. Individual microbes and strains can differentially influence ENS activity and neurochemistry. In this review we will briefly summarise the role of the microbiota on ENS development, and, in some more detail, explore the mechanisms by which the microbiota can influence ENS activity and function.

  1. The influence of print exposure on the body-object interaction effect in visual word recognition

    PubMed Central

    Hansen, Dana; Siakaluk, Paul D.; Pexman, Penny M.

    2012-01-01

    We examined the influence of print exposure on the body-object interaction (BOI) effect in visual word recognition. High print exposure readers and low print exposure readers either made semantic categorizations (“Is the word easily imageable?”; Experiment 1) or phonological lexical decisions (“Does the item sound like a real English word?”; Experiment 2). The results from Experiment 1 showed that there was a larger BOI effect for the low print exposure readers than for the high print exposure readers in semantic categorization, though an effect was observed for both print exposure groups. However, the results from Experiment 2 showed that the BOI effect was observed only for the high print exposure readers in phonological lexical decision. The results of the present study suggest that print exposure does influence the BOI effect, and that this influence varies as a function of task demands. PMID:22563312

  2. Phase Diagrams of Nuclear Pasta

    NASA Astrophysics Data System (ADS)

    Caplan, Matthew; Horowitz, Chuck; Berry, Don; da Silva Schneider, Andre

    2016-03-01

    In the inner crust of neutrons stars, where matter is near the saturation density, protons and neutrons arrange themselves into complex structures called nuclear pasta. Early theoretical work predicted a simple graduated hierarchy of pasta phases, consisting of spheres, cylinders, slabs, and uniform matter with voids. Previous work has simulated these phases with a simple classical model and has shown that the formation of these structures is dependent on the temperature, density, and proton fraction. However, previous work only studied a limited range of these parameters due to computational limitations. Thanks to recent advances in computing it is now possible to survey the structure of nuclear pasta for a larger range of parameters. By simulating nuclear pasta with constant temperature and proton fraction in an expanding simulation volume we are able to study the phase transitions in nuclear pasta, and thus produce a set of phase diagrams. We report on these phase diagrams as well as newly identified phases of nuclear pasta and discuss their implications for neutron star observables.

  3. Genetic influences on growth and body composition in mice: multilocus interactions

    PubMed Central

    Ankra-Badu, Georgina A.; Pomp, Daniel; Shriner, Daniel; Allison, David B.; Yi, Nengjun

    2011-01-01

    Background The genetic architecture of body weight and body composition is complex because these traits are normally influenced by multiple genes and their interactions, even after controlling for the environment. Bayesian methodology provides an efficient way of estimating these interactions. Subjects and measurements We used Bayesian model selection techniques to estimate the effect of epistatic interactions on age-related body weight (at 3, 6, and 10 weeks) and body composition (organ weights and fat-related traits) in an F2 sample obtained from a cross between high-growth (M16i) mice and low-growth (L6) mice. Results We observed epistatic and main-effect quantitative trait loci (QTL) that controlled both body weight and body composition. Epistatic effects were generally more significant for WK3 and WK6 than WK10. Chromosomes 5 and 13 interacted strongly to control body weight at 3 weeks. A pleiotropic QTL on chromosome 2 was associated with body weight and some body composition phenotypes. Testis weight was regulated by a QTL on chromosome 13 with a significantly large main effect. Conclusion By analyzing epistatic interactions, we detected QTL not found in a previous analysis of this mouse population. Hence, the detection of gene-gene interactions may provide new information about the genetic architecture of complex obesity-related traits and may lead to the detection of additional obesity genes. PMID:18982013

  4. Evolutionary Influenced Interaction Pattern as Indicator for the Investigation of Natural Variants Causing Nephrogenic Diabetes Insipidus.

    PubMed

    Grunert, Steffen; Labudde, Dirk

    2015-01-01

    The importance of short membrane sequence motifs has been shown in many works and emphasizes the related sequence motif analysis. Together with specific transmembrane helix-helix interactions, the analysis of interacting sequence parts is helpful for understanding the process during membrane protein folding and in retaining the three-dimensional fold. Here we present a simple high-throughput analysis method for deriving mutational information of interacting sequence parts. Applied on aquaporin water channel proteins, our approach supports the analysis of mutational variants within different interacting subsequences and finally the investigation of natural variants which cause diseases like, for example, nephrogenic diabetes insipidus. In this work we demonstrate a simple method for massive membrane protein data analysis. As shown, the presented in silico analyses provide information about interacting sequence parts which are constrained by protein evolution. We present a simple graphical visualization medium for the representation of evolutionary influenced interaction pattern pairs (EIPPs) adapted to mutagen investigations of aquaporin-2, a protein whose mutants are involved in the rare endocrine disorder known as nephrogenic diabetes insipidus, and membrane proteins in general. Furthermore, we present a new method to derive new evolutionary variations within EIPPs which can be used for further mutagen laboratory investigations.

  5. Soil abiotic factors influence interactions between belowground herbivores and plant roots.

    PubMed

    Erb, Matthias; Lu, Jing

    2013-03-01

    Root herbivores are important ecosystem drivers and agricultural pests, and, possibly as a consequence, plants protect their roots using a variety of defensive strategies. One aspect that distinguishes belowground from aboveground plant-insect interactions is that roots are constantly exposed to a set of soil-specific abiotic factors. These factors can profoundly influence root resistance, and, consequently, the outcome of the interaction with belowground feeders. In this review, we synthesize the current literature on the impact of soil moisture, nutrients, and texture on root-herbivore interactions. We show that soil abiotic factors influence the interaction by modulating herbivore abundance and behaviour, root growth and resistance, beneficial microorganisms, as well as natural enemies of the herbivores. We suggest that abiotic heterogeneity may explain the high variability that is often encountered in root-herbivore systems. We also propose that under abiotic stress, the relative fitness value of the roots and the potential negative impact of herbivory increases, which may lead to a higher defensive investment and an increased recruitment of beneficial microorganisms by the plant. At the same time, both root-feeding herbivores and natural enemies are likely to decrease in abundance under extreme environmental conditions, leading to a context- and species-specific impact on plant fitness. Only by using tightly controlled experiments that include soil abiotic heterogeneity will it be possible to understand the impact of root feeders on an ecosystem scale and to develop predictive models for pest occurrence and impact.

  6. Polymer segregation under confinement: Influences of macromolecular crowding and the interaction between the polymer and crowders

    NASA Astrophysics Data System (ADS)

    Chen, Yuhao; Yu, Wancheng; Wang, Jiajun; Luo, Kaifu

    2015-10-01

    Entropy driven polymer segregation in confinements as a model for chromosome separation in bacteria has attracted wide attention; however, the effects of macromolecular crowding and the interaction between the binding protein and the newly replicated DNA on the segregation dynamics are not clear. Using Langevin dynamics simulations, we investigate the influences of crowders and the attractive interaction between the polymer and a small number of crowders on segregation of two overlapping polymers under a cylindrical confinement. We find that the segregation time increases with increasing the volume fraction of crowders due to the slower chain diffusion in crowded environments. For a fixed volume fraction of crowders, the segregation time decreases with increasing the size of crowders. Moreover, the attractive interaction between the polymer and a small number of crowders can significantly facilitate the chain segregation. These results are important for understanding the chromosome segregation in living cells.

  7. Cascading processes and interactions in torrent catchments and their influence on the damage pattern

    NASA Astrophysics Data System (ADS)

    Keiler, Margreth; Gebbers, David

    2014-05-01

    Research on single geomorphological processes during damaging events has a long history; however, comprehensive documentations and analyses of the events have been conducted not until the late 1980s. Thus, for highly damaging events insights about triggering, the evolution and the impacts of processes during an event and the resulting damage were produced. Though, in the majority of cases the processes were studied in a well-defined procedure of one disciplinary focus. These focused studies neglect mutable influences which may alter the sequence of the process or the event. During damaging events multiple geomorphological processes are active which leads to the assumption that they have a certain impact on each other and the course of damaging effect. Consequently, for a comprehensive hazard and risk analysis all processes of a catchment have to be analysed and evaluated quantitatively and qualitatively (MARZOCCHI, 2007). Although the demand for a sophisticated risk management is increasing, the research on interactions as well as on physical vulnerability to multiple hazards, including the different processes impact effects, is still very limited (KAPPES et al., 2010, 2011). The challenges in this field are the quantity of data needed, and furthermore to conduct this kind of analysis is very complex and complicated (KAPPES et al. 2012). Yet, knowledge about possible interactions and resulting impact effects could significantly contribute to the reduction of risk in a region. The objective of this study is to analyse, i) how geomorphological processes interact with each other and with other factors of the surrounding during a damaging event, ii) what influences those interactions have on the resulting damage of the event and iii) whether or not different events are comparable in terms of those interactions and their impacts. To meet these objectives, 15 damaging torrent events, which occurred between 2000 and 2011 in the Bernese Oberland and the Pennine Alps

  8. Influence of substrate interaction and confinement on electric-field-induced transition in symmetric block-copolymer thin films.

    PubMed

    Mukherjee, Arnab; Mukherjee, Rajdip; Ankit, Kumar; Bhattacharya, Avisor; Nestler, Britta

    2016-03-01

    In the present work, we study morphologies arising due to competing substrate interaction, electric field, and confinement effects on a symmetric diblock copolymer. We employ a coarse-grained nonlocal Cahn-Hilliard phenomenological model taking into account the appropriate contributions of substrate interaction and electrostatic field. The proposed model couples the Ohta-Kawasaki functional with Maxwell equation of electrostatics, thus alleviating the need for any approximate solution used in previous studies. We calculate the phase diagram in electric-field-substrate strength space for different film thicknesses. In addition to identifying the presence of parallel, perpendicular, and mixed lamellae phases similar to analytical calculations, we also find a region in the phase diagram where hybrid morphologies (combination of two phases) coexist. These hybrid morphologies arise either solely due to substrate affinity and confinement or are induced due to the applied electric field. The dependence of the critical fields for transition between the various phases on substrate strength, film thickness, and dielectric contrast is discussed. Some preliminary 3D results are also presented to corroborate the presence of hybrid morphologies. PMID:27078402

  9. Influence of substrate interaction and confinement on electric-field-induced transition in symmetric block-copolymer thin films

    NASA Astrophysics Data System (ADS)

    Mukherjee, Arnab; Mukherjee, Rajdip; Ankit, Kumar; Bhattacharya, Avisor; Nestler, Britta

    2016-03-01

    In the present work, we study morphologies arising due to competing substrate interaction, electric field, and confinement effects on a symmetric diblock copolymer. We employ a coarse-grained nonlocal Cahn-Hilliard phenomenological model taking into account the appropriate contributions of substrate interaction and electrostatic field. The proposed model couples the Ohta-Kawasaki functional with Maxwell equation of electrostatics, thus alleviating the need for any approximate solution used in previous studies. We calculate the phase diagram in electric-field-substrate strength space for different film thicknesses. In addition to identifying the presence of parallel, perpendicular, and mixed lamellae phases similar to analytical calculations, we also find a region in the phase diagram where hybrid morphologies (combination of two phases) coexist. These hybrid morphologies arise either solely due to substrate affinity and confinement or are induced due to the applied electric field. The dependence of the critical fields for transition between the various phases on substrate strength, film thickness, and dielectric contrast is discussed. Some preliminary 3D results are also presented to corroborate the presence of hybrid morphologies.

  10. Influence of the number of topologically interacting neighbors on swarm dynamics

    PubMed Central

    Shang, Yilun; Bouffanais, Roland

    2014-01-01

    Recent empirical and theoretical works on collective behaviors based on a topological interaction are beginning to offer some explanations as for the physical reasons behind the selection of a particular number of nearest neighbors locally affecting each individual's dynamics. Recently, flocking starlings have been shown to topologically interact with a very specific number of neighbors, between six to eight, while metric-free interactions were found to govern human crowd dynamics. Here, we use network- and graph-theoretic approaches combined with a dynamical model of locally interacting self-propelled particles to study how the consensus reaching process and its dynamics are influenced by the number k of topological neighbors. Specifically, we prove exactly that, in the absence of noise, consensus is always attained with a speed to consensus strictly increasing with k. The analysis of both speed and time to consensus reveals that, irrespective of the swarm size, a value of k ~ 10 speeds up the rate of convergence to consensus to levels close to the one of the optimal all-to-all interaction signaling. Furthermore, this effect is found to be more pronounced in the presence of environmental noise. PMID:24567077

  11. Early adversity and combat exposure interact to influence anterior cingulate cortex volume in combat veterans☆

    PubMed Central

    Woodward, Steven H.; Kuo, Janice R.; Schaer, Marie; Kaloupek, Danny G.; Eliez, Stephan

    2013-01-01

    Objective Childhood and combat trauma have been observed to interact to influence amygdala volume in a sample of U.S. military veterans with and without PTSD. This interaction was assessed in a second, functionally-related fear system component, the pregenual and dorsal anterior cingulate cortex, using the same sample and modeling approach. Method Anterior cingulate cortical tissues (gray + white matter) were manually-delineated in 1.5 T MR images in 87 U.S. military veterans of the Vietnam and Persian Gulf wars. Hierarchical multiple regression modeling was used to assess associations between anterior cingulate volume and the following predictors, trauma prior to age 13, combat exposure, the interaction of early trauma and combat exposure, and PTSD diagnosis. Results As previously observed in the amygdala, unique variance in anterior cingulate cortical volume was associated with both the diagnosis of PTSD and with the interaction of childhood and combat trauma. The pattern of the latter interaction indicated that veterans with childhood trauma exhibited a significant inverse linear relationship between combat trauma and anterior cingulate volume while those without childhood trauma did not. Such associations were not observed in hippocampal or total cerebral tissue volumes. Conclusions In the dorsal anterior cingulate cortex, as in the amygdala, early trauma may confer excess sensitivity to later combat trauma. PMID:24179818

  12. On the influence of ram-pressure stripping on interacting galaxies in clusters

    NASA Astrophysics Data System (ADS)

    Kapferer, W.; Kronberger, T.; Ferrari, C.; Riser, T.; Schindler, S.

    2008-09-01

    We investigate the influence of ram pressure on the star-formation rate and the distribution of gas and stellar matter in interacting model galaxies in clusters. To simulate the baryonic and non-baryonic components of interacting disc galaxies moving through a hot, thin medium, we use a combined N-body/hydrodynamic code GADGET2 with a description for star formation based on density thresholds. Two identical model spiral galaxies on a collision trajectory with three different configurations were investigated in detail. In the first configuration, the galaxies collide without the presence of an ambient medium. In the second configurations, the ram pressure acts face-on on the interacting galaxies and in the third configuration the ram pressure acts edge-on. The ambient medium is thin (10-28gcm-3), hot (3keV ~ 3.6 × 107 K) and has a relative velocity of 1000kms-1, to mimic an average low ram pressure in the outskirts of galaxy clusters. The interaction velocities are comparable to galaxy interactions in groups, falling along filaments into galaxy clusters. The global star-formation rate of the interacting system is enhanced in the presence of ram pressure by a factor of 3 in comparison to the same interaction without the presence of an ambient medium. The tidal tails and the gaseous bridge of the interacting system are almost completely destroyed by the ram pressure. The amount of gas in the wake of the interacting system is ~50 per cent of the total gas of the colliding galaxies after 500Myr the galaxies start to feel the ram pressure. Nearly ~10-15 per cent in mass of all newly formed stars are formed in the wake of the interacting system at distances larger than 20 kpc behind the stellar discs. As the tidal tails and the gaseous bridge between the interacting systems feel the ram pressure, knots of cold gas (T < 1 × 105 K) start to form. These irregular structures contain several 106Msolar of cold gas and newly formed stars and, as the ram pressure acts on them

  13. Hubble's diagram and cosmic expansion

    NASA Astrophysics Data System (ADS)

    Kirshner, Robert P.

    2004-01-01

    Edwin Hubble's classic article on the expanding universe appeared in PNAS in 1929 [Hubble, E. P. (1929) Proc. Natl. Acad. Sci. USA 15, 168-173]. The chief result, that a galaxy's distance is proportional to its redshift, is so well known and so deeply embedded into the language of astronomy through the Hubble diagram, the Hubble constant, Hubble's Law, and the Hubble time, that the article itself is rarely referenced. Even though Hubble's distances have a large systematic error, Hubble's velocities come chiefly from Vesto Melvin Slipher, and the interpretation in terms of the de Sitter effect is out of the mainstream of modern cosmology, this article opened the way to investigation of the expanding, evolving, and accelerating universe that engages today's burgeoning field of cosmology.

  14. Hubble's diagram and cosmic expansion.

    PubMed

    Kirshner, Robert P

    2004-01-01

    Edwin Hubble's classic article on the expanding universe appeared in PNAS in 1929 [Hubble, E. P. (1929) Proc. Natl. Acad. Sci. USA 15, 168-173]. The chief result, that a galaxy's distance is proportional to its redshift, is so well known and so deeply embedded into the language of astronomy through the Hubble diagram, the Hubble constant, Hubble's Law, and the Hubble time, that the article itself is rarely referenced. Even though Hubble's distances have a large systematic error, Hubble's velocities come chiefly from Vesto Melvin Slipher, and the interpretation in terms of the de Sitter effect is out of the mainstream of modern cosmology, this article opened the way to investigation of the expanding, evolving, and accelerating universe that engages today's burgeoning field of cosmology. PMID:14695886

  15. Phase diagram of ammonium nitrate.

    PubMed

    Dunuwille, Mihindra; Yoo, Choong-Shik

    2013-12-01

    Ammonium Nitrate (AN) is a fertilizer, yet becomes an explosive upon a small addition of chemical impurities. The origin of enhanced chemical sensitivity in impure AN (or AN mixtures) is not well understood, posing significant safety issues in using AN even today. To remedy the situation, we have carried out an extensive study to investigate the phase stability of AN and its mixtures with hexane (ANFO-AN mixed with fuel oil) and Aluminum (Ammonal) at high pressures and temperatures, using diamond anvil cells (DAC) and micro-Raman spectroscopy. The results indicate that pure AN decomposes to N2, N2O, and H2O at the onset of the melt, whereas the mixtures, ANFO and Ammonal, decompose at substantially lower temperatures. The present results also confirm the recently proposed phase IV-IV' transition above 17 GPa and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400°C.

  16. Phase diagram of ammonium nitrate

    NASA Astrophysics Data System (ADS)

    Dunuwille, Mihindra; Yoo, Choong-Shik

    2013-12-01

    Ammonium Nitrate (AN) is a fertilizer, yet becomes an explosive upon a small addition of chemical impurities. The origin of enhanced chemical sensitivity in impure AN (or AN mixtures) is not well understood, posing significant safety issues in using AN even today. To remedy the situation, we have carried out an extensive study to investigate the phase stability of AN and its mixtures with hexane (ANFO-AN mixed with fuel oil) and Aluminum (Ammonal) at high pressures and temperatures, using diamond anvil cells (DAC) and micro-Raman spectroscopy. The results indicate that pure AN decomposes to N2, N2O, and H2O at the onset of the melt, whereas the mixtures, ANFO and Ammonal, decompose at substantially lower temperatures. The present results also confirm the recently proposed phase IV-IV' transition above 17 GPa and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400°C.

  17. Hubble's diagram and cosmic expansion

    PubMed Central

    Kirshner, Robert P.

    2004-01-01

    Edwin Hubble's classic article on the expanding universe appeared in PNAS in 1929 [Hubble, E. P. (1929) Proc. Natl. Acad. Sci. USA 15, 168–173]. The chief result, that a galaxy's distance is proportional to its redshift, is so well known and so deeply embedded into the language of astronomy through the Hubble diagram, the Hubble constant, Hubble's Law, and the Hubble time, that the article itself is rarely referenced. Even though Hubble's distances have a large systematic error, Hubble's velocities come chiefly from Vesto Melvin Slipher, and the interpretation in terms of the de Sitter effect is out of the mainstream of modern cosmology, this article opened the way to investigation of the expanding, evolving, and accelerating universe that engages today's burgeoning field of cosmology. PMID:14695886

  18. Phase diagram of ammonium nitrate

    NASA Astrophysics Data System (ADS)

    Dunuwille, M.; Yoo, C. S.

    2014-05-01

    Ammonium Nitrate (AN) has often subjected to uses in improvised explosive devices, due to its wide availability as a fertilizer and its capability of becoming explosive with slight additions of organic and inorganic compounds. Yet, the origin of enhanced energetic properties of impure AN (or AN mixtures) is neither chemically unique nor well understood -resulting in rather catastrophic disasters in the past1 and thereby a significant burden on safety in using ammonium nitrates even today. To remedy this situation, we have carried out an extensive study to investigate the phase stability of AN at high pressure and temperature, using diamond anvil cells and micro-Raman spectroscopy. The present results confirm the recently proposed phase IV-to-IV' transition above 17 GPa2 and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400 °C.

  19. Mathematical review on source-type diagrams

    NASA Astrophysics Data System (ADS)

    Aso, Naofumi; Ohta, Kazuaki; Ide, Satoshi

    2016-03-01

    A source-type diagram is a visualization tool used to display earthquake sources, including double-couples, compensated linear vector dipoles, and isotropic deformation. Together with recent observations of non-double-couple events in a variety of tectonic settings, it is important to be able to recognize the source type intuitively from a representative diagram. Since previous works have proposed diagrams created using a range of projections, we review these diagrams in the framework of the moment tensor eigenvalue space. For further applications, we also provide complete formulas for conversion between moment tensor representation and the coordinate system of each diagram style. Using both a global catalog and synthetic data, we discuss differences between types of diagrams and the relative effectiveness of each.

  20. Continuation of point clouds via persistence diagrams

    NASA Astrophysics Data System (ADS)

    Gameiro, Marcio; Hiraoka, Yasuaki; Obayashi, Ippei

    2016-11-01

    In this paper, we present a mathematical and algorithmic framework for the continuation of point clouds by persistence diagrams. A key property used in the method is that the persistence map, which assigns a persistence diagram to a point cloud, is differentiable. This allows us to apply the Newton-Raphson continuation method in this setting. Given an original point cloud P, its persistence diagram D, and a target persistence diagram D‧, we gradually move from D to D‧, by successively computing intermediate point clouds until we finally find a point cloud P‧ having D‧ as its persistence diagram. Our method can be applied to a wide variety of situations in topological data analysis where it is necessary to solve an inverse problem, from persistence diagrams to point cloud data.

  1. Influence of polymer-surfactant interactions on o/w emulsion properties and microcapsule formation.

    PubMed

    Petrovic, Lidija B; Sovilj, Verica J; Katona, Jaroslav M; Milanovic, Jadranka L

    2010-02-15

    The aim of this work was to investigate the influence of interactions between 1.00%w/w hydroxypropylmethyl cellulose (HPMC) and the anionic surfactant sodium dodecylsulfate (SDS) on the properties of 20%w/w sunflower oil/water emulsion and the corresponding microcapsules obtained by spray drying technique. On the basis of the viscosity and rheological measurements, particle size and particle size distribution, and stability assessment, it was concluded that the emulsion characteristics depend strongly on the interaction mechanism. Significant increase in viscosity and non-Newtonian thixotropic behavior was observed in the SDS concentration range from 0.15 to 1.00%w/v, corresponding to HPMC-SDS interactions in the continuous phase. In the interaction region, a three-dimensional network is formed in the continuous phase by intermolecular binding of SDS molecules to the adjacent HPMC chains, which contributes to increase in the viscosity and thixotropic properties. The mean diameter of emulsion particles, d(vs), decreases with increase in SDS concentration, but emulsion stability depends on the adsorption layer structure, i.e. HPMC-SDS interactions. The HPMC/SDS complex adsorbed at the o/w interface makes the layer more compact, enhancing thus emulsion stability. Microcapsules, obtained in the form of powder by spray drying of emulsions, have good redispersibility in water, but their stability changes depending on the HPMC-SDS interaction mechanism, i.e., the HPMC/SDS complex forms a more compact layer that is resistant to breaking during the drying process. The highest encapsulation efficiency was found in the interaction region.

  2. The surprising influence of late charged current weak interactions on Big Bang Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Grohs, E.; Fuller, George M.

    2016-10-01

    The weak interaction charged current processes (νe + n ↔ p +e-; νbare + p ↔ n +e+; n ↔ p +e- +νbare) interconvert neutrons and protons in the early universe and have significant influence on Big Bang Nucleosynthesis (BBN) light-element abundance yields, particularly that for 4He. We demonstrate that the influence of these processes is still significant even when they operate well below temperatures T ∼ 0.7 MeV usually invoked for "weak freeze-out," and in fact down nearly into the alpha-particle formation epoch (T ≈ 0.1 MeV). This physics is correctly captured in commonly used BBN codes, though this late-time, low-temperature persistent effect of the isospin-changing weak processes, and the sensitivity of the associated rates to lepton energy distribution functions and blocking factors are not widely appreciated. We quantify this late-time influence by analyzing weak interaction rate dependence on the neutron lifetime, lepton energy distribution functions, entropy, the proton-neutron mass difference, and Hubble expansion rate. The effects we point out here render BBN a keen probe of any beyond-standard-model physics that alters lepton number/energy distributions, even subtly, in epochs of the early universe all the way down to near T = 100 keV.

  3. The neptunium-iron phase diagram

    NASA Astrophysics Data System (ADS)

    Gibson, J. K.; Haire, R. G.; Beahm, E. C.; Gensini, M. M.; Maeda, A.; Ogawa, T.

    1994-08-01

    The phase relations in the Np-Fe alloy system have been elucidated using differential thermal analysis. A phase diagram for this system is postulated based upon the experimental results, regular-solution model calculations, and an expected correspondence to the U-Fe and Pu-Fe diagrams. The postulated Np-Fe diagram is characterized by limited terminal solid solubilities, two intermetallic solid phases, NpFe 2 and Np 6Fe, and two eutectics.

  4. Symmetric Monotone Venn Diagrams with Seven Curves

    NASA Astrophysics Data System (ADS)

    Cao, Tao; Mamakani, Khalegh; Ruskey, Frank

    An n-Venn diagram consists of n curves drawn in the plane in such a way that each of the 2 n possible intersections of the interiors and exteriors of the curves forms a connected non-empty region. A k-region in a diagram is a region that is in the interior of precisely k curves. A n-Venn diagram is symmetric if it has a point of rotation about which rotations of the plane by 2π/n radians leaves the diagram fixed; it is polar symmetric if it is symmetric and its stereographic projection about the infinite outer face is isomorphic to the projection about the innermost face. A Venn diagram is monotone if every k-region is adjacent to both some (k - 1)-region (if k > 0) and also to some k + 1 region (if k < n). A Venn diagram is simple if at most two curves intersect at any point. We prove that the "Grünbaum" encoding uniquely identifies monotone simple symmetric n-Venn diagrams and describe an algorithm that produces an exhaustive list of all of the monotone simple symmetric n-Venn diagrams. There are exactly 23 simple monotone symmetric 7-Venn diagrams, of which 6 are polar symmetric.

  5. Measurement uncertainty of liquid chromatographic analyses visualized by Ishikawa diagrams.

    PubMed

    Meyer, Veronika R

    2003-09-01

    Ishikawa, or cause-and-effect diagrams, help to visualize the parameters that influence a chromatographic analysis. Therefore, they facilitate the set up of the uncertainty budget of the analysis, which can then be expressed in mathematical form. If the uncertainty is calculated as the Gaussian sum of all uncertainty parameters, it is necessary to quantitate them all, a task that is usually not practical. The other possible approach is to use the intermediate precision as a base for the uncertainty calculation. In this case, it is at least necessary to consider the uncertainty of the purity of the reference material in addition to the precision data. The Ishikawa diagram is then very simple, and so is the uncertainty calculation. This advantage is given by the loss of information about the parameters that influence the measurement uncertainty.

  6. Influence of compressibility on the Lagrangian statistics of vorticity-strain-rate interactions.

    PubMed

    Danish, Mohammad; Sinha, Sawan Suman; Srinivasan, Balaji

    2016-07-01

    The objective of this study is to investigate the influence of compressibility on Lagrangian statistics of vorticity and strain-rate interactions. The Lagrangian statistics are extracted from "almost" time-continuous data sets of direct numerical simulations of compressible decaying isotropic turbulence by employing a cubic spline-based Lagrangian particle tracker. We study the influence of compressibility on Lagrangian statistics of alignment in terms of compressibility parameters-turbulent Mach number, normalized dilatation-rate, and flow topology. In comparison to incompressible turbulence, we observe that the presence of compressibility in a flow field weakens the alignment tendency of vorticity toward the largest strain-rate eigenvector. Based on the Lagrangian statistics of alignment conditioned on dilatation and topology, we find that the weakened tendency of alignment observed in compressible turbulence is because of a special group of fluid particles that have an initially negligible dilatation-rate and are associated with stable-focus-stretching topology. PMID:27575211

  7. Influence of compressibility on the Lagrangian statistics of vorticity-strain-rate interactions.

    PubMed

    Danish, Mohammad; Sinha, Sawan Suman; Srinivasan, Balaji

    2016-07-01

    The objective of this study is to investigate the influence of compressibility on Lagrangian statistics of vorticity and strain-rate interactions. The Lagrangian statistics are extracted from "almost" time-continuous data sets of direct numerical simulations of compressible decaying isotropic turbulence by employing a cubic spline-based Lagrangian particle tracker. We study the influence of compressibility on Lagrangian statistics of alignment in terms of compressibility parameters-turbulent Mach number, normalized dilatation-rate, and flow topology. In comparison to incompressible turbulence, we observe that the presence of compressibility in a flow field weakens the alignment tendency of vorticity toward the largest strain-rate eigenvector. Based on the Lagrangian statistics of alignment conditioned on dilatation and topology, we find that the weakened tendency of alignment observed in compressible turbulence is because of a special group of fluid particles that have an initially negligible dilatation-rate and are associated with stable-focus-stretching topology.

  8. Emotion and narrative fiction: Interactive influences before, during, and after reading.

    PubMed

    Mar, Raymond A; Oatley, Keith; Djikic, Maja; Mullin, Justin

    2011-08-01

    Emotions are central to the experience of literary narrative fiction. Affect and mood can influence what book people choose, based partly on whether their goal is to change or maintain their current emotional state. Once having chosen a book, the narrative itself acts to evoke and transform emotions, both directly through the events and characters depicted and through the cueing of emotionally valenced memories. Once evoked by the story, these emotions can in turn influence a person's experience of the narrative. Lastly, emotions experienced during reading may have consequences after closing the covers of a book. This article reviews the current state of empirical research for each of these stages, providing a snapshot of what is known about the interaction between emotions and literary narrative fiction. With this, we can begin to sketch the outlines of what remains to be discovered. PMID:21824023

  9. Influence of compressibility on the Lagrangian statistics of vorticity-strain-rate interactions

    NASA Astrophysics Data System (ADS)

    Danish, Mohammad; Sinha, Sawan Suman; Srinivasan, Balaji

    2016-07-01

    The objective of this study is to investigate the influence of compressibility on Lagrangian statistics of vorticity and strain-rate interactions. The Lagrangian statistics are extracted from "almost" time-continuous data sets of direct numerical simulations of compressible decaying isotropic turbulence by employing a cubic spline-based Lagrangian particle tracker. We study the influence of compressibility on Lagrangian statistics of alignment in terms of compressibility parameters—turbulent Mach number, normalized dilatation-rate, and flow topology. In comparison to incompressible turbulence, we observe that the presence of compressibility in a flow field weakens the alignment tendency of vorticity toward the largest strain-rate eigenvector. Based on the Lagrangian statistics of alignment conditioned on dilatation and topology, we find that the weakened tendency of alignment observed in compressible turbulence is because of a special group of fluid particles that have an initially negligible dilatation-rate and are associated with stable-focus-stretching topology.

  10. Interaction of Mean Temperature and Daily Fluctuation Influences Dengue Incidence in Dhaka, Bangladesh.

    PubMed

    Sharmin, Sifat; Glass, Kathryn; Viennet, Elvina; Harley, David

    2015-01-01

    Local weather influences the transmission of the dengue virus. Most studies analyzing the relationship between dengue and climate are based on relatively coarse aggregate measures such as mean temperature. Here, we include both mean temperature and daily fluctuations in temperature in modelling dengue transmission in Dhaka, the capital of Bangladesh. We used a negative binomial generalized linear model, adjusted for rainfall, anomalies in sea surface temperature (an index for El Niño-Southern Oscillation), population density, the number of dengue cases in the previous month, and the long term temporal trend in dengue incidence. In addition to the significant associations of mean temperature and temperature fluctuation with dengue incidence, we found interaction of mean and temperature fluctuation significantly influences disease transmission at a lag of one month. High mean temperature with low fluctuation increases dengue incidence one month later. Besides temperature, dengue incidence was also influenced by sea surface temperature anomalies in the current and previous month, presumably as a consequence of concomitant anomalies in the annual rainfall cycle. Population density exerted a significant positive influence on dengue incidence indicating increasing risk of dengue in over-populated Dhaka. Understanding these complex relationships between climate, population, and dengue incidence will help inform outbreak prediction and control.

  11. Interaction of Mean Temperature and Daily Fluctuation Influences Dengue Incidence in Dhaka, Bangladesh

    PubMed Central

    Sharmin, Sifat; Glass, Kathryn; Viennet, Elvina; Harley, David

    2015-01-01

    Local weather influences the transmission of the dengue virus. Most studies analyzing the relationship between dengue and climate are based on relatively coarse aggregate measures such as mean temperature. Here, we include both mean temperature and daily fluctuations in temperature in modelling dengue transmission in Dhaka, the capital of Bangladesh. We used a negative binomial generalized linear model, adjusted for rainfall, anomalies in sea surface temperature (an index for El Niño-Southern Oscillation), population density, the number of dengue cases in the previous month, and the long term temporal trend in dengue incidence. In addition to the significant associations of mean temperature and temperature fluctuation with dengue incidence, we found interaction of mean and temperature fluctuation significantly influences disease transmission at a lag of one month. High mean temperature with low fluctuation increases dengue incidence one month later. Besides temperature, dengue incidence was also influenced by sea surface temperature anomalies in the current and previous month, presumably as a consequence of concomitant anomalies in the annual rainfall cycle. Population density exerted a significant positive influence on dengue incidence indicating increasing risk of dengue in over-populated Dhaka. Understanding these complex relationships between climate, population, and dengue incidence will help inform outbreak prediction and control. PMID:26161895

  12. Teacher-student classroom interactions: the influence of gender, academic dominance, and teacher communication style.

    PubMed

    Ilatov, Z Z; Shamai, S; Hertz-Lazarovitz, R; Mayer-Young, S

    1998-01-01

    Two Israeli grade 7 classes, with different teachers, were monitored and the lessons coded according to categories that were based on the conceptual framework of speech acts theory combined with role theory. The two classes differed in their academic composition: one class was dominated by females and the other was balanced by gender. Different classroom interactions were observed. The two teachers manifested different communication styles: one exercised more control, while the other was more influenced by the dominant students. The teachers did not have any bias against females; they were "gender blind." Thus, the findings indicated that gender, academic composition, and teacher communication style are important factors in teacher-student interactions. PMID:9706314

  13. Specific interaction of capsid protein and importin-{alpha}/{beta} influences West Nile virus production

    SciTech Connect

    Bhuvanakantham, Raghavan; Chong, Mun-Keat; Ng, Mah-Lee

    2009-11-06

    West Nile virus (WNV) capsid (C) protein has been shown to enter the nucleus of infected cells. However, the mechanism by which C protein enters the nucleus is unknown. In this study, we have unveiled for the first time that nuclear transport of WNV and Dengue virus C protein is mediated by their direct association with importin-{alpha}. This interplay is mediated by the consensus sequences of bipartite nuclear localization signal located between amino acid residues 85-101 together with amino acid residues 42 and 43 of C protein. Elucidation of biological significance of importin-{alpha}/C protein interaction demonstrated that the binding efficiency of this association influenced the nuclear entry of C protein and virus production. Collectively, this study illustrated the molecular mechanism by which the C protein of arthropod-borne flavivirus enters the nucleus and showed the importance of importin-{alpha}/C protein interaction in the context of flavivirus life-cycle.

  14. A genetic interaction between the APP and Dab1 genes influences brain development

    PubMed Central

    Pramatarova, Albéna; Chen, Kelian; Howell, Brian W.

    2008-01-01

    The Dab1 docking protein is required for the proper organization of brain laminae and for a signal transduction pathway initiated by Reelin binding to the ApoER2 and VLDLR receptors on the cell surface of neurons. Dab1 physically interacts with APP, however, it is not known whether the APP gene influences Dab1 function. Here we demonstrate a genetic interaction between Dab1 and APP. Dab1-hypomorphic animals have neuronal ectopias in the neocortex and reduced cerebellar volume, possibly a consequence of Purkinje cell misplacement. These phenotypes are exacerbated in transgenic animals overexpressing a mutant form of APP, APPswe, which is characterized by increased processing at the β-secretase site. The Dab1-hypomorphic phenotype is improved in the cerebellum of animals that are deficient for APP. Together this suggests that APP expression constrains the consequences of Dab1 activity during brain development. PMID:18029196

  15. Influence of interfacial Dzyaloshinskii-Moriya interaction on the parametric amplification of spin waves

    SciTech Connect

    Verba, Roman; Tiberkevich, Vasil; Slavin, Andrei

    2015-09-14

    The influence of the interfacial Dzyaloshinskii-Moriya interaction (IDMI) on the parametric amplification of spin waves propagating in ultrathin ferromagnetic film is considered theoretically. It is shown that the IDMI changes the relation between the group velocities of the signal and idler spin waves in a parametric amplifier, which may result in the complete vanishing of the reversed idler wave. In the optimized case, the idler spin wave does not propagate from the pumping region at all, which increases the efficiency of the amplification of the signal wave and suppresses the spurious impact of the idler waves on neighboring spin-wave processing devices.

  16. Influence of emitted electrons transiting between surfaces on plasma-surface interaction

    SciTech Connect

    Campanell, Michael; Wang, Hongyue

    2013-09-02

    Emitted electrons are accelerated back into the plasma by the sheath. If their mean free path is large, they can propagate directly to another surface without suffering collisions. We analyze the effects of “transit” on plasma-surface interaction. When transit occurs, surfaces exchanging electrons are intricately coupled. All surfaces float more negatively than they would if the emission collisionally remixed with the bulk plasma. Asymmetries of the system drive a net “transit current” between the surfaces, which influences their potential difference. The larger the initial energy spread of the emitted electrons, the larger the potential difference.

  17. Platelet receptor polymorphisms do not influence Staphylococcus aureus-platelet interactions or infective endocarditis.

    PubMed

    Daga, Shruti; Shepherd, James G; Callaghan, J Garreth S; Hung, Rachel K Y; Dawson, Dana K; Padfield, Gareth J; Hey, Shi Y; Cartwright, Robyn A; Newby, David E; Fitzgerald, J Ross

    2011-03-01

    Cardiac vegetations result from bacterium-platelet adherence, activation and aggregation, and are associated with increased morbidity and mortality in infective endocarditis. The GPIIb/IIIa and FcγRIIa platelet receptors play a central role in platelet adhesion, activation and aggregation induced by endocarditis pathogens such as Staphylococcus aureus, but the influence of known polymorphisms of these receptors on the pathogenesis of infective endocarditis is unknown. We determined the GPIIIa platelet antigen Pl(A1/A2) and FcγRIIa H131R genotype of healthy volunteers (n = 160) and patients with infective endocarditis (n = 40), and investigated the influence of these polymorphisms on clinical outcome in infective endocarditis and S. aureus-platelet interactions in vitro. Platelet receptor genotype did not correlate with development of infective endocarditis, vegetation characteristics on echocardiogram or the composite clinical end-point of embolism, heart failure, need for surgery or mortality (P > 0.05 for all), even though patients with the GPIIIa Pl(A1/A1) genotype had increased in vivo platelet activation (P = 0.001). Furthermore, neither GPIIIa Pl(A1/A2) nor FcγRIIa H131R genotype influenced S. aureus-induced platelet adhesion, activation or aggregation in vitro (P > 0.05). Taken together, our data suggest that the GPIIIa and FcγRIIa platelet receptor polymorphisms do not influence S. aureus-platelet interactions in vitro or the clinical course of infective endocarditis.

  18. Influence of nonelectrostatic ion-ion interactions on double-layer capacitance

    NASA Astrophysics Data System (ADS)

    Zhao, Hui

    2012-11-01

    Recently a Poisson-Helmholtz-Boltzmann (PHB) model [Bohinc , Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.85.031130 85, 031130 (2012)] was developed by accounting for solvent-mediated nonelectrostatic ion-ion interactions. Nonelectrostatic interactions are described by a Yukawa-like pair potential. In the present work, we modify the PHB model by adding steric effects (finite ion size) into the free energy to derive governing equations. The modified PHB model is capable of capturing both ion specificity and ion crowding. This modified model is then employed to study the capacitance of the double layer. More specifically, we focus on the influence of nonelectrostatic ion-ion interactions on charging a double layer near a flat surface in the presence of steric effects. We numerically compute the differential capacitance as a function of the voltage under various conditions. At small voltages and low salt concentrations (dilute solution), we find out that the predictions from the modified PHB model are the same as those from the classical Poisson-Boltzmann theory, indicating that nonelectrostatic ion-ion interactions and steric effects are negligible. At moderate voltages, nonelectrostatic ion-ion interactions play an important role in determining the differential capacitance. Generally speaking, nonelectrostatic interactions decrease the capacitance because of additional nonelectrostatic repulsion among excess counterions inside the double layer. However, increasing the voltage gradually favors steric effects, which induce a condensed layer with crowding of counterions near the electrode. Accordingly, the predictions from the modified PHB model collapse onto those computed by the modified Poisson-Boltzmann theory considering steric effects alone. Finally, theoretical predictions are compared and favorably agree with experimental data, in particular, in concentrated solutions, leading one to conclude that the modified PHB model adequately predicts the diffuse

  19. Junction Protein Shrew-1 Influences Cell Invasion and Interacts with Invasion-promoting Protein CD147

    PubMed Central

    Schreiner, Alexander; Ruonala, Mika; Jakob, Viktor; Suthaus, Jan; Boles, Eckhard; Wouters, Fred

    2007-01-01

    Shrew-1 was previously isolated from an endometriotic cell line in our search for invasion-associated genes. It proved to be a membrane protein that targets to the basolateral membrane of polarized epithelial cells, interacting with E-cadherin–catenin complexes of adherens junctions. Paradoxically, the existence of adherens junctions is incompatible with invasion. To investigate whether shrew-1 can indeed influence cellular invasion, we overexpressed it in HT1080 fibrosarcoma cells. This resulted in enhanced invasiveness, accompanied by an increased matrix metalloprotease (MMP)-9 level in the supernatant, raising the question about the role of shrew-1 in this process. Logic suggested we looked for an interaction with CD147, a known promoter of invasiveness and MMP activity. Indeed, genetics-based, biochemical, and microscopy experiments revealed shrew-1– and CD147-containing complexes in invasive endometriotic cells and an interaction in epithelial cells, which was stronger in MCF7 tumor cells, but weaker in Madin-Darby canine kidney cells. In contrast to the effect mediated by overexpression, small interfering RNA-mediated down-regulation of either shrew-1 or CD147 in HeLa cells decreased invasiveness without affecting the proliferation behavior of HeLa cells, but the knockdown cells displayed decreased motility. Altogether, our results imply that shrew-1 has a function in the regulation of cellular invasion, which may involve its interaction with CD147. PMID:17267690

  20. Environmental influences on virus-host interactions in an Australian subtropical reservoir.

    PubMed

    Säwström, Christin; Pollard, Peter

    2012-02-01

    Viral and prokaryotic interactions in freshwaters have been investigated worldwide but there are few temporal studies in the tropics and none in the sub-tropics. In this 10-month study, we examined temporal changes in virus-host interactions and viral life cycles (lytic versus lysogenic) in relation to the prevailing environmental conditions in a subtropical water reservoir (Wivenhoe) in southeast Queensland, Australia. Heterotrophic prokaryotes and picocyanobacteria were positively correlated with concentrations of viruses throughout the study, indicating the presence of both bacteriophages and cyanophages in the reservoir. The percentage of heterotrophic prokaryotes and picocyanobacteria containing intracellular viruses (FVIC) ranged between 0.2% and 2.4% and did not vary significantly over the 10-month study, whereas lysogenic heterotrophic prokaryotes were only detected in the drier months of June and July. Spearman rank correlation analysis showed that the oxidative-reduction potential (ORP) of the water reservoir influenced the concentrations of viruses, heterotrophic prokaryotes and picocyanobacteria significantly, with low ORP offering a favourable environment for these components. There was a negative relationship between FVIC and rainfall suggesting the associated run-off altered virus-host interactions. Overall, our study provides novel information and inferences on how virus-host interactions in subtropical freshwaters might respond to changes in precipitation predicted to occur with global climate change. PMID:23757232

  1. Environmental influences on virus-host interactions in an Australian subtropical reservoir.

    PubMed

    Säwström, Christin; Pollard, Peter

    2012-02-01

    Viral and prokaryotic interactions in freshwaters have been investigated worldwide but there are few temporal studies in the tropics and none in the sub-tropics. In this 10-month study, we examined temporal changes in virus-host interactions and viral life cycles (lytic versus lysogenic) in relation to the prevailing environmental conditions in a subtropical water reservoir (Wivenhoe) in southeast Queensland, Australia. Heterotrophic prokaryotes and picocyanobacteria were positively correlated with concentrations of viruses throughout the study, indicating the presence of both bacteriophages and cyanophages in the reservoir. The percentage of heterotrophic prokaryotes and picocyanobacteria containing intracellular viruses (FVIC) ranged between 0.2% and 2.4% and did not vary significantly over the 10-month study, whereas lysogenic heterotrophic prokaryotes were only detected in the drier months of June and July. Spearman rank correlation analysis showed that the oxidative-reduction potential (ORP) of the water reservoir influenced the concentrations of viruses, heterotrophic prokaryotes and picocyanobacteria significantly, with low ORP offering a favourable environment for these components. There was a negative relationship between FVIC and rainfall suggesting the associated run-off altered virus-host interactions. Overall, our study provides novel information and inferences on how virus-host interactions in subtropical freshwaters might respond to changes in precipitation predicted to occur with global climate change.

  2. Scaling analysis and application: Phase diagram of magnetic nanorings and elliptical nanoparticles

    SciTech Connect

    Zhang Wen; Singh, Rohit; Bray-Ali, Noah; Haas, Stephan

    2008-04-01

    The magnetic properties of single-domain nanoparticles with different geometric shapes, crystalline anisotropies, and lattice structures are investigated. A recently proposed scaling approach is shown to be universal and in agreement with dimensional analysis coupled with the assumption of incomplete self-similarity. It is used to obtain phase diagrams of magnetic nanoparticles featuring three competing configurations: in-plane ferromagnetism, out-of-plane ferromagnetism, and vortex formation. The influence of the vortex core on the scaling behavior and phase diagram is analyzed. Three-dimensional phase diagrams are obtained for cylindrical nanorings depending on their height and outer and inner radii. The triple points in these phase diagrams are shown to be in a linear relationship with the inner radius of the ring. Elliptically shaped magnetic nanoparticles are also studied. A new parametrization for double vortex configurations is proposed, and regions in the phase diagram where the double vortex is a stable ground state are identified.

  3. Seasonal Influences on Ground-Surface Water Interactions in an Arsenic-Affected Aquifer in Cambodia

    NASA Astrophysics Data System (ADS)

    Richards, L. A.; Magnone, D.; Van Dongen, B.; Bryant, C.; Boyce, A.; Ballentine, C. J.; Polya, D. A.

    2015-12-01

    Millions of people in South and Southeast Asia consume drinking water daily which contains dangerous levels of arsenic exceeding health-based recommendations [1]. A key control on arsenic mobilization in aquifers in these areas has been controversially identified as the interaction of 'labile' organic matter contained in surface waters with groundwaters and sediments at depth [2-4], which may trigger the release of arsenic from the solid- to aqueous-phase via reductive dissolution of iron-(hyr)oxide minerals [5]. In a field site in Kandal Province, Cambodia, which is an arsenic-affected area typical to others in the region, there are strong seasonal patterns in groundwater flow direction, which are closely related to monsoonal rains [6] and may contribute to arsenic release in this aquifer. The aim of this study is to explore the implications of the high susceptibility of this aquifer system to seasonal changes on potential ground-surface water interactions. The main objectives are to (i) identify key zones where there are likely ground-surface water interactions, (ii) assess the seasonal impact of such interactions and (iii) quantify the influence of interactions using geochemical parameters (such as As, Fe, NO3, NH4, 14C, 3T/3He, δ18O, δ2H). Identifying the zones, magnitude and seasonal influence of ground-surface water interactions elucidates new information regarding potential locations/pathways of arsenic mobilization and/or transport in affected aquifers and may be important for water management strategies in affected areas. This research is supported by NERC (NE/J023833/1) to DP, BvD and CJB and a NERC PhD studentship (NE/L501591/1) to DM. References: [1] World Health Organization, 2008. [2] Charlet & Polya (2006), Elements, 2, 91-96. [3] Harvey et al. (2002), Science, 298, 1602-1606. [4] Lawson et al. (2013), Env. Sci. Technol. 47, 7085 - 7094. [5] Islam et al. (2004), Nature, 430, 68-71. [6] Benner et al. (2008) Appl. Geochem. 23(11), 3072 - 3087.

  4. Phase Diagram of Ammonium Nitrate

    NASA Astrophysics Data System (ADS)

    Dunuwille, Mihindra; Yoo, Choong-Shik

    2013-06-01

    Ammonium Nitrate (AN) has often been subjected to uses in improvised explosive devices, due to its wide availability as a fertilizer and its capability of becoming explosive with slight additions of organic and inorganic compounds. Yet, the origin of enhanced energetic properties of impure AN (or AN mixtures) is neither chemically unique nor well understood - resulting in rather catastrophic disasters in the past1 and thereby a significant burden on safety, in using ammonium nitrates even today. To remedy this situation, we have carried out an extensive study to investigate the phase stability of AN, in different chemical environments, at high pressure and temperature, using diamond anvil cells and micro-Raman spectroscopy. The present results confirm the recently proposed phase IV-to-IV' transition above 15 GPa2 and provide new constraints for the melting and phase diagram of AN to 40 GPa and 673 K. The present study has been supported by the U.S. DHS under Award Number 2008-ST-061-ED0001.

  5. Phase diagram of ammonium nitrate

    SciTech Connect

    Dunuwille, Mihindra; Yoo, Choong-Shik

    2013-12-07

    Ammonium Nitrate (AN) is a fertilizer, yet becomes an explosive upon a small addition of chemical impurities. The origin of enhanced chemical sensitivity in impure AN (or AN mixtures) is not well understood, posing significant safety issues in using AN even today. To remedy the situation, we have carried out an extensive study to investigate the phase stability of AN and its mixtures with hexane (ANFO–AN mixed with fuel oil) and Aluminum (Ammonal) at high pressures and temperatures, using diamond anvil cells (DAC) and micro-Raman spectroscopy. The results indicate that pure AN decomposes to N{sub 2}, N{sub 2}O, and H{sub 2}O at the onset of the melt, whereas the mixtures, ANFO and Ammonal, decompose at substantially lower temperatures. The present results also confirm the recently proposed phase IV-IV{sup ′} transition above 17 GPa and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400°C.

  6. Mucoadhesion on pig vesical mucosa: influence of polycarbophil/calcium interactions.

    PubMed

    Kerec, M; Bogataj, M; Mugerle, B; Gasperlin, M; Mrhar, A

    2002-07-01

    The influence of polycarbophil/calcium interactions on the mucoadhesive properties of polycarbophil has been examined. Polycarbophil dispersions and films with different concentrations of calcium or sodium ions were prepared and the following parameters were measured: detachment force on pig vesical mucosa, zeta potential, pH and viscosity. Polycarbophil detachment force decreased significantly in the presence of calcium but not sodium. Both ions decrease the pH of polycarbophil dispersions. On the other hand, altering the pH of hydrated polycarbophil films in the absence of added ions had an insignificant effect on detachment force. Both ions reduce the absolute values of polycarbophil zeta potential, calcium more efficiently than sodium. We could conclude that decreased mucoadhesion strength of polycarbophil in the presence of calcium is due to the chelation of polycarbophil carboxylic groups by calcium and crosslinking of polymer. The crosslinked polymer chains would be expected to be less flexible, and therefore, interpenetrate to a lesser extent with the glycosaminoglycans of mucus. Additionally, the interactions between functional groups of polycarbophil and mucus glycosaminoglycans are lowered due to the calcium, blocking the carboxylic groups. The mechanism of calcium influence on viscosity of polycarbophil dispersions appears to be different: repulsion between ionised carboxylic groups of polycarbophil prevails over the crosslinking of polycarbophil by calcium.

  7. Invasive earthworms interact with abiotic conditions to influence the invasion of common buckthorn (Rhamnus cathartica).

    PubMed

    Roth, Alexander M; Whitfeld, Timothy J S; Lodge, Alexandra G; Eisenhauer, Nico; Frelich, Lee E; Reich, Peter B

    2015-05-01

    Common buckthorn (Rhamnus cathartica L.) is one of the most abundant and ecologically harmful non-native plants in forests of the Upper Midwest United States. At the same time, European earthworms are invading previously glaciated areas in this region, with largely anecdotal evidence suggesting they compound the negative effects of buckthorn and influence the invasibility of these forests. Germination and seedling establishment are important control points for colonization by any species, and manipulation of the conditions influencing these life history stages may provide insight into why invasive species are successful in some environments and not others. Using a greenhouse microcosm experiment, we examined the effects of important biotic and abiotic factors on the germination and seedling establishment of common buckthorn. We manipulated light levels, leaf litter depth and earthworm presence to investigate the independent and interactive effects of these treatments on buckthorn establishment. We found that light and leaf litter depth were significant predictors of buckthorn germination but that the presence of earthworms was the most important factor; earthworms interacted with light and leaf litter to increase the number and biomass of buckthorn across all treatments. Path analysis suggested both direct and moisture-mediated indirect mechanisms controlled these processes. The results suggest that the action of earthworms may provide a pathway through which buckthorn invades forests of the Upper Midwest United States. Hence, researchers and managers should consider co-invasion of plants and earthworms when investigating invasibility and creating preemptive or post-invasion management plans.

  8. Dynamic phase diagram of soft nanocolloids.

    PubMed

    Gupta, Sudipta; Camargo, Manuel; Stellbrink, Jörg; Allgaier, Jürgen; Radulescu, Aurel; Lindner, Peter; Zaccarelli, Emanuela; Likos, Christos N; Richter, Dieter

    2015-09-01

    We present a comprehensive experimental and theoretical study covering micro-, meso- and macroscopic length and time scales, which enables us to establish a generalized view in terms of structure-property relationship and equilibrium dynamics of soft colloids. We introduce a new, tunable block copolymer model system, which allows us to vary the aggregation number, and consequently its softness, by changing the solvophobic-to-solvophilic block ratio (m : n) over two orders of magnitude. Based on a simple and general coarse-grained model of the colloidal interaction potential, we verify the significance of interaction length σint governing both structural and dynamic properties. We put forward a quantitative comparison between theory and experiment without adjustable parameters, covering a broad range of experimental polymer volume fractions (0.001 ≤ϕ≤ 0.5) and regimes from ultra-soft star-like to hard sphere-like particles, that finally results in the dynamic phase diagram of soft colloids. In particular, we find throughout the concentration domain a strong correlation between mesoscopic diffusion and macroscopic viscosity, irrespective of softness, manifested in data collapse on master curves using the interaction length σint as the only relevant parameter. A clear reentrance in the glass transition at high aggregation numbers is found, recovering the predicted hard-sphere (HS) value in the hard-sphere like limit. Finally, the excellent agreement between our new experimental systems with different but already established model systems shows the relevance of block copolymer micelles as a versatile realization of soft colloids and the general validity of a coarse-grained approach for the description of the structure and dynamics of soft colloids. PMID:26219628

  9. Electrostatic, elastic and hydration-dependent interactions in dermis influencing volume exclusion and macromolecular transport.

    PubMed

    Øien, Alf H; Wiig, Helge

    2016-07-01

    Interstitial exclusion refers to the limitation of space available for plasma proteins and other macromolecules based on collagen and negatively charged glycosaminoglycans (GAGs) in the interstitial space. It is of particular importance to interstitial fluid and plasma volume regulation. Here we present a novel mechanical and mathematical model of the dynamic interactions of structural elements within the interstitium of the dermis at the microscopic level that may explain volume exclusion of charged and neutral macroparticles. At this level, the interstitium is considered to consist of elements called extracellular matrix (ECM) cells, again containing two main interacting structural components on a fluid background including anions and cations setting up osmotic forces: one smaller GAG component, having an intrinsic expansive electric force, and one bigger collagen component, having an intrinsic elastic force. Because of size differences, the GAG component interacts with a fraction of the collagen component only at normal hydration. This fraction, however, increases with rising hydration as a consequence of the modeled form of the interaction force between the GAGs and collagen. Collagen is locally displaced at variable degrees as hydration changes. Two models of GAGs are considered, having largely different geometries which demands different, but related, forms of GAG-collagen interaction forces. The effects of variable fixed charges on GAGs and of GAG density in tissue are evaluated taking into account observed volume exclusion properties of charged macromolecules as a function of tissue hydration. The presented models may improve our biophysical understanding of acting forces influencing tissue fluid dynamics. Such knowledge is significant when evaluating the transport of electrically charged and neutral macromolecules into and through the interstitium, and therefore to drug uptake and the therapeutic effects of macromolecular agents. PMID:27079466

  10. Interleukin-6 promoter polymorphism interacts with pain and life stress influencing depression phenotypes.

    PubMed

    Kovacs, David; Eszlari, Nora; Petschner, Peter; Pap, Dorottya; Vas, Szilvia; Kovacs, Peter; Gonda, Xenia; Bagdy, Gyorgy; Juhasz, Gabriella

    2016-05-01

    Interleukin-6 (IL-6) has emerged as a potent biomarker for depression as its elevated plasma levels in patients with clinical depression have been confirmed by meta-analyses. Increased plasma IL-6 concentration was associated with various psychological stress factors and physical disorders accompanied by pain. Another modulator of the IL-6 level is rs1800795, a promoter polymorphism in the IL-6 gene which is able to influence its expression rate. Therefore, we examined in a Hungarian population sample of 1053 volunteers with European origins if rs1800795 polymorphism can affect depression symptoms measured by Zung Self-rating Depression Scale (ZSDS), and Brief Symptom Inventory (BSI). We also investigated the interactions of the polymorphism with reported painful physical conditions and Recent Negative Life Events (RLE) measured by the List of Life Threatening Experiences. Rs1800795 significantly interacted with both RLE and painful condition on depressive symptoms measured by ZSDS and BSI using different heritability models, while no main effects of the polymorphism were identified. After correction for multiple testing only the rs1800795 × RLE interaction effect (recessive model) remained significant on the BSI score, while both RLE and painful conditions significantly interacted on the ZSDS. In conclusion, the functional IL-6 rs1800795 polymorphism in interaction with various stress factors increases the risk of depression and has a greater impact on symptoms measured by the ZSDS. Thus, IL-6 and other cytokines may be more relevant in the development of somatic symptoms compared to affective signs of depression, delineating a specific genotype-phenotype relationship in this heterogeneous disorder.

  11. Influence of trifluoroethanol on membrane interfacial anchoring interactions of transmembrane alpha-helical peptides.

    PubMed

    Ozdirekcan, Suat; Nyholm, Thomas K M; Raja, Mobeen; Rijkers, Dirk T S; Liskamp, Rob M J; Killian, J Antoinette

    2008-02-15

    Interfacial anchoring interactions between aromatic amino acid residues and the lipid-water interface are believed to be important determinants for membrane protein structure and function. Thus, it is possible that molecules that partition into the lipid-water interface can influence membrane protein activity simply by interfering with these anchoring interactions. Here we tested this hypothesis by investigating the effects of 2,2,2-trifluoroethanol (TFE) on the interaction of a Trp-flanked synthetic transmembrane peptide (acetyl-GW(2)(LA)(8)LW(2)A-NH(2)) with model membranes of dimyristoylphosphatidylcholine. Two striking observations were made. First, using (2)H nuclear magnetic resonance on acyl chain deuterated lipids, we found that addition of 4 or 8 vol % of TFE completely abolishes the ability of the peptide to order and stretch the lipid acyl chains in these relatively thin bilayers. Second, we observed that addition of 8 vol % TFE reduces the tilt angle of the peptide from 5.3 degrees to 2.5 degrees, as measured by (2)H NMR on Ala-d(4) labeled peptides. The "straightening" of the peptide was accompanied by an increased exposure of Trp to the aqueous phase, as shown by Trp-fluorescence quenching experiments using acrylamide. The observation of a reduced tilt angle was surprising because we also found that TFE partioning results in a significant thinning of the membrane, which would increase the extent of hydrophobic mismatch. In contrast to the Trp-flanked peptide, no effect of TFE was observed on the interaction of a Lys-flanked analog (acetyl-GK(2)(LA)(8)LK(2)A-NH(2)) with the lipid bilayer. These results emphasize the importance of interfacial anchoring interactions for membrane organization and provide new insights into how molecules such as TFE that can act as anesthetics may affect the behavior of membrane proteins that are enriched in aromatic amino acids at the lipid-water interface.

  12. Free-Body Diagrams: Necessary or Sufficient?

    NASA Astrophysics Data System (ADS)

    Rosengrant, David; Van Heuvelen, Alan; Etkina, Eugenia

    2005-09-01

    The Rutgers PAER group is working to help students develop various scientific abilities. One of the abilities is to create, understand and learn to use for qualitative reasoning and problem solving different representations of physical processes such as pictorial representations, motion diagrams, free-body diagrams, and energy bar charts. Physics education literature indicates that using multiple representations is beneficial for student understanding of physics ideas and for problem solving. We developed a special approach to construct and utilize free-body diagrams for representing physical phenomena and for problem solving. We will examine whether students draw free-body diagrams in solving problems when they know they will not receive credit for it; the consistency of their use in different conceptual areas; and if students who use free-body diagrams while solving problems in different areas of physics are more successful then those who do not.

  13. Influence of molecular shape, conformability, net surface charge, and tissue interaction on transscleral macromolecular diffusion.

    PubMed

    Srikantha, Nishanthan; Mourad, Fatma; Suhling, Klaus; Elsaid, Naba; Levitt, James; Chung, Pei Hua; Somavarapu, Satyanarayana; Jackson, Timothy L

    2012-09-01

    The purpose of this study was to investigate the influence of molecular shape, conformability, net surface charge and tissue interaction on transscleral diffusion. Unfixed, porcine sclera was clamped in an Ussing chamber. Fluorophore-labelled neutral albumin, neutral dextran, or neutral ficoll were placed in one hemi-chamber and the rate of transscleral diffusion was measured over 24 h using a spectrophotometer. Experiments were repeated using dextrans and ficoll with positive or negative net surface charges. Fluorescence recovery after photobleaching (FRAP) was undertaken to compare transscleral diffusion with diffusion through a solution. All molecules were 70 kDa. With FRAP, the diffusion coefficient (D) of neutral molecules was highest for albumin, followed by ficoll, then dextran (p < 0.0001). Positive dextrans diffused fastest, followed by negative, then neutral dextrans (p = 0.0004). Neutral ficoll diffused the fastest, followed by positive then negative ficoll (p = 0.5865). For the neutral molecules, transscleral D was highest for albumin, followed by dextran, then ficoll (p < 0.0001). D was highest for negative ficoll, followed by neutral, then positive ficoll (p < 0.0001). By contrast, D was highest for positive dextran, followed by neutral, then negative dextran (p = 0.0021). In conclusion, diffusion in free solution does not predict transscleral diffusion and the molecular-tissue interaction is important. Molecular size, shape, and charge may all markedly influence transscleral diffusion, as may conformability to a lesser degree, but their effects may be diametrically opposed in different molecules, and their influence on diffusion is more complex than previously thought. Each variable cannot be considered in isolation, and the interplay of all these variables needs to be tested, when selecting or designing drugs for transscleral delivery. PMID:22846670

  14. Influence of molecular shape, conformability, net surface charge, and tissue interaction on transscleral macromolecular diffusion.

    PubMed

    Srikantha, Nishanthan; Mourad, Fatma; Suhling, Klaus; Elsaid, Naba; Levitt, James; Chung, Pei Hua; Somavarapu, Satyanarayana; Jackson, Timothy L

    2012-09-01

    The purpose of this study was to investigate the influence of molecular shape, conformability, net surface charge and tissue interaction on transscleral diffusion. Unfixed, porcine sclera was clamped in an Ussing chamber. Fluorophore-labelled neutral albumin, neutral dextran, or neutral ficoll were placed in one hemi-chamber and the rate of transscleral diffusion was measured over 24 h using a spectrophotometer. Experiments were repeated using dextrans and ficoll with positive or negative net surface charges. Fluorescence recovery after photobleaching (FRAP) was undertaken to compare transscleral diffusion with diffusion through a solution. All molecules were 70 kDa. With FRAP, the diffusion coefficient (D) of neutral molecules was highest for albumin, followed by ficoll, then dextran (p < 0.0001). Positive dextrans diffused fastest, followed by negative, then neutral dextrans (p = 0.0004). Neutral ficoll diffused the fastest, followed by positive then negative ficoll (p = 0.5865). For the neutral molecules, transscleral D was highest for albumin, followed by dextran, then ficoll (p < 0.0001). D was highest for negative ficoll, followed by neutral, then positive ficoll (p < 0.0001). By contrast, D was highest for positive dextran, followed by neutral, then negative dextran (p = 0.0021). In conclusion, diffusion in free solution does not predict transscleral diffusion and the molecular-tissue interaction is important. Molecular size, shape, and charge may all markedly influence transscleral diffusion, as may conformability to a lesser degree, but their effects may be diametrically opposed in different molecules, and their influence on diffusion is more complex than previously thought. Each variable cannot be considered in isolation, and the interplay of all these variables needs to be tested, when selecting or designing drugs for transscleral delivery.

  15. The Influence of Social Interaction on the Perception of Emotional Expression: A Case Study with a Robot Head

    NASA Astrophysics Data System (ADS)

    Murray, John C.; Cañamero, Lola; Bard, Kim A.; Ross, Marina Davila; Thorsteinsson, Kate

    In this paper we focus primarily on the influence that socio-emotional interaction has on the perception of emotional expression by a robot. We also investigate and discuss the importance of emotion expression in socially interactive situations involving human robot interaction (HRI), and show the importance of utilising emotion expression when dealing with interactive robots, that are to learn and develop in socially situated environments. We discuss early expressional development and the function of emotion in communication in humans and how this can improve HRI communications. Finally we provide experimental results showing how emotion-rich interaction via emotion expression can affect the HRI process by providing additional information.

  16. Organizational Influences on Interdisciplinary Interactions during Research and Design of Large-Scale Complex Engineered Systems

    NASA Technical Reports Server (NTRS)

    McGowan, Anna-Maria R.; Seifert, Colleen M.; Papalambros, Panos Y.

    2012-01-01

    The design of large-scale complex engineered systems (LaCES) such as an aircraft is inherently interdisciplinary. Multiple engineering disciplines, drawing from a team of hundreds to thousands of engineers and scientists, are woven together throughout the research, development, and systems engineering processes to realize one system. Though research and development (R&D) is typically focused in single disciplines, the interdependencies involved in LaCES require interdisciplinary R&D efforts. This study investigates the interdisciplinary interactions that take place during the R&D and early conceptual design phases in the design of LaCES. Our theoretical framework is informed by both engineering practices and social science research on complex organizations. This paper provides preliminary perspective on some of the organizational influences on interdisciplinary interactions based on organization theory (specifically sensemaking), data from a survey of LaCES experts, and the authors experience in the research and design. The analysis reveals couplings between the engineered system and the organization that creates it. Survey respondents noted the importance of interdisciplinary interactions and their significant benefit to the engineered system, such as innovation and problem mitigation. Substantial obstacles to interdisciplinarity are uncovered beyond engineering that include communication and organizational challenges. Addressing these challenges may ultimately foster greater efficiencies in the design and development of LaCES and improved system performance by assisting with the collective integration of interdependent knowledge bases early in the R&D effort. This research suggests that organizational and human dynamics heavily influence and even constrain the engineering effort for large-scale complex systems.

  17. Interaction of triprolidine hydrochloride with serum albumins: thermodynamic and binding characteristics, and influence of site probes.

    PubMed

    Sandhya, B; Hegde, Ashwini H; Kalanur, Shankara S; Katrahalli, Umesha; Seetharamappa, J

    2011-04-01

    The interaction between triprolidine hydrochloride (TRP) to serum albumins viz. bovine serum albumin (BSA) and human serum albumin (HSA) has been studied by spectroscopic methods. The experimental results revealed the static quenching mechanism in the interaction of TRP with protein. The number of binding sites close to unity for both TRP-BSA and TRP-HSA indicated the presence of single class of binding site for the drug in protein. The binding constant values of TRP-BSA and TRP-HSA were observed to be 4.75 ± 0.018 × 10(3) and 2.42 ± 0.024 × 10(4)M(-1) at 294 K, respectively. Thermodynamic parameters indicated that the hydrogen bond and van der Waals forces played the major role in the binding of TRP to proteins. The distance of separation between the serum albumin and TRP was obtained from the Förster's theory of non-radioactive energy transfer. The metal ions viz., K(+), Ca(2+), Co(2+), Cu(2+), Ni(2+), Mn(2+) and Zn(2+) were found to influence the binding of the drug to protein. Displacement experiments indicated the binding of TRP to Sudlow's site I on both BSA and HSA. The CD, 3D fluorescence spectra and FT-IR spectral results revealed the changes in the secondary structure of protein upon interaction with TRP.

  18. Dynamics and Interactions of OmpF and LPS: Influence on Pore Accessibility and Ion Permeability.

    PubMed

    Patel, Dhilon S; Re, Suyong; Wu, Emilia L; Qi, Yifei; Klebba, Phillip E; Widmalm, Göran; Yeom, Min Sun; Sugita, Yuji; Im, Wonpil

    2016-02-23

    The asymmetric outer membrane of Gram-negative bacteria is formed of the inner leaflet with phospholipids and the outer leaflet with lipopolysaccharides (LPS). Outer membrane protein F (OmpF) is a trimeric porin responsible for the passive transport of small molecules across the outer membrane of Escherichia coli. Here, we report the impact of different levels of heterogeneity in LPS environments on the structure and dynamics of OmpF using all-atom molecular dynamics simulations. The simulations provide insight into the flexibility and dynamics of LPS components that are highly dependent on local environments, with lipid A being the most rigid and O-antigen being the most flexible. Increased flexibility of O-antigen polysaccharides is observed in heterogeneous LPS systems, where the adjacent O-antigen repeating units are weakly interacting and thus more dynamic, compared to homogeneous LPS systems in which LPS interacts strongly with each other with limited overall flexibility due to dense packing. The model systems were validated by comparing molecular-level details of interactions between OmpF surface residues and LPS core sugars with experimental data, establishing the importance of LPS core oligosaccharides in shielding OmpF surface epitopes recognized by monoclonal antibodies. There are LPS environmental influences on the movement of bulk ions (K(+) and Cl(-)), but the ion selectivity of OmpF is mainly affected by bulk ion concentration. PMID:26910429

  19. Social interactions influence dopamine and octopamine homeostasis in the brain of the ant Formica japonica.

    PubMed

    Wada-Katsumata, Ayako; Yamaoka, Ryohei; Aonuma, Hitoshi

    2011-05-15

    In ants, including Formica japonica, trophallaxis and grooming are typical social behaviors shared among nestmates. After depriving ants of either food or nestmates and then providing them with either food or nestmates, a behavioral change in type and frequency of social interactions was observed. We hypothesized that starvation and isolation affected levels of brain biogenic amines including dopamine (DA) and octopamine (OA) - neuromediators modifying various insect behaviors - and tested the relationship between brain biogenic amines and social behaviors of stressed ants. Ants starved for 7 days contained lower brain DA levels and they did not perform trophallaxis toward nestmates. Feeding starved ants sucrose solution re-established trophallaxis but not brain DA levels. The performance of trophallaxis induced recovery of brain DA content to the level of untreated ants. Ants that were isolated for 2 days displayed markedly increased OA levels, which following nestmate interactions, returned to levels similar to those of control (non-isolated) ants and ants isolated for 1 h. We conclude that: (1) starvation reduced brain DA level but had no significant effect on brain OA (trophallaxis recovered the brain DA levels), and (2) isolation increased brain OA level but had no effect on brain DA (trophallaxis and grooming events recovered the brain OA levels). We suggest that social interactions with nestmates influenced brain biogenic amine homeostasis in stressed F. japonica.

  20. Influence of copper on the interaction between cytochrome c and sulfite in vitro.

    PubMed

    Wang, Jinsheng; Guo, Dongsheng; Yuan, Xiaoying

    2006-01-01

    The quantitative influence of copper on the interaction between cytochrome c and sulfite, which is a derivate of sulfur dioxide in the human body, has been studied by fluorescence spectrometry and ultraviolet absorption spectrometry in vitro. The results indicate that copper may intensely combine with protein component and ferroporphyrin component in cytochrome c at the concentration of 0.1 mM, and the respective association constants (K(A)) are 3.77 x 10(4) L mol(-1) and 9.38 x 10(3) L mol(-1). Sulfite has little interaction with the protein component in cytochrome c (K(A) = 0.094 L mol(-1)), at either low concentrations or relatively high concentrations (<0.15 M). However, it can react with the ferroporphyrin component in cytochrome c (K(A) = 4.297 L mol(-1)). After copper is added to the sulfite-cytochrome c binary systems, the reaction between sulfite and the protein component in cytochrome c is obviously strengthened at a low concentration (K(A) = 7.289 L mol(-1)), while the addition of copper merely has a little effect on the interaction between sulfite and the ferroporphyrin component in cytochrome c. PMID:17009250

  1. Legionella-protozoa-nematode interactions in aquatic biofilms and influence of Mip on Caenorhabditis elegans colonization.

    PubMed

    Rasch, Janine; Krüger, Stefanie; Fontvieille, Dominique; Ünal, Can M; Michel, Rolf; Labrosse, Aurélie; Steinert, Michael

    2016-09-01

    Legionella pneumophila, the causative agent of Legionnaireś disease, is naturally found in aquatic habitats. The intracellular life cycle within protozoa pre-adapted the "accidental" human pathogen to also infect human professional phagocytes like alveolar macrophages. Previous studies employing the model organism Caenorhabditis elegans suggest that also nematodes might serve as a natural host for L. pneumophila. Here, we report for the first time from a natural co-habitation of L. pneumophila and environmental nematode species within biofilms of a warm water spring. In addition, we identified the protozoan species Oxytricha bifaria, Stylonychia mytilus, Ciliophrya sp. which have never been described as potential interaction partners of L. pneumophila before. Modeling and dissection of the Legionella-protozoa-nematode interaction revealed that C. elegans ruptures Legionella-infected amoebal cells and by this means incorporate the pathogen. Further infection studies revealed that the macrophage infectivity potentiator (Mip) protein of L. pneumophila, which is known to bind collagen IV during human lung infection, promotes the colonization of the intestinal tract of L4 larvae of C. elegans and negatively influences the life span of the worms. The Mip-negative L. pneumophila mutant exhibited a 32-fold reduced colonization rate of the nematodes after 48h when compared to the wild-type strain. Taken together, these studies suggest that nematodes may serve as natural hosts for L. pneumophila, promote their persistence and dissemination in the environment, and co-evolutionarily pre-adapt the pathogen for interactions with extracellular constituents of human lung tissue.

  2. The influence of inelastic neutrino interactions with light clusters on core-collapse supernova simulations

    NASA Astrophysics Data System (ADS)

    Furusawa, Shun; Nagakura, Hiroki; Sumiyoshi, Kohsuke; Yamada, Shoichi

    2014-12-01

    We perform numerical experiments to investigate the influence of inelastic neutrino reactions with light clusters in hot nuclear matter on core-collapse supernova simulations. These interactions have been neglected in most hydrodynamical supernova simulations. The neutrino absorptions and inelastic interactions with deuterons, tritons, helions and alpha particles are taken into account in the hydrodynamical simulations in addition to the ordinary charged- current interactions with nucleons. Axial symmetry is assumed but no equatorial symmetry is imposed. The time evolutions of shock waves are calculated with a simple light-bulb approximation for the neutrino transport and a multi-nuclei equation of state. We show that the heating rates of deuterons reach as high as ~ 10% of those of nucleons around the bottom of the gain region. On the other hand, alpha particles heat the matter near the shock wave, which is important when the shock wave expands and density and temperature of matter become low. It is also found that the models with heating by light clusters have different evolutions from those without it in non-linear evolution phase. The matter in the gain region has various densities and temperatures and there appear regions that are locally rich in deuterons and alpha particles. These results indicate that the inelastic reactions of light clusters, especially deuterons, should be incorporated in the simulations of core-collapse supernovae.

  3. Phase diagrams of scalemic mixtures: A Monte Carlo simulation study

    NASA Astrophysics Data System (ADS)

    Vlot, Margot J.; van Miltenburg, J. Cornelis; Oonk, Harry A. J.; van der Eerden, Jan P.

    1997-12-01

    In this paper, a simplified model was used to describe the interactions between the enantiomers in a scalemic mixture. Monte Carlo simulations were performed to determine several thermodynamic properties as a function of temperature and mole fraction of solid, liquid, and gas phase. Phase diagrams were constructed using a macroscopic thermodynamic program, PROPHASE. The model consists of spherical D and L molecules interacting via modified Lennard-Jones potentials (σDD=σLL, ɛDD=ɛLL, ɛDL=eɛDD, and σDL=sσDD.) The two heterochiral interaction parameters, e and s, were found to be sufficient to produce all types of phase diagrams that have been found for these systems experimentally. Conglomerates were found when the heterochiral interaction strength was smaller than the homochiral value, e<1. A different heterochiral interaction distance, s≠1, led to racemic compounds, with an ordered distribution of D and L molecules. The CsCl-structured compound was found to be stable for short DL interactions, s<1 (e=1), with an enantiotropic transition to a solid solution for s=0.96. Longer heterochiral distances, s>1, result in the formation of layered fcc compounds. The liquid regions in the phase diagram become larger for s≠1, caused by a strong decrease of the melting point for s<1 and s>1, in combination with only a small effect on the boiling point for s<1, and even an increase of the boiling point for s>1. Segregation into two different solid solutions, one with low mole fraction and the other one close to x=0.25, was obtained for these mixtures as well.

  4. State diagrams for harmonically trapped bosons in optical lattices

    SciTech Connect

    Rigol, Marcos; Batrouni, George G.; Rousseau, Valery G.; Scalettar, Richard T.

    2009-05-15

    We use quantum Monte Carlo simulations to obtain zero-temperature state diagrams for strongly correlated lattice bosons in one and two dimensions under the influence of a harmonic confining potential. Since harmonic traps generate a coexistence of superfluid and Mott insulating domains, we use local quantities such as the quantum fluctuations of the density and a local compressibility to identify the phases present in the inhomogeneous density profiles. We emphasize the use of the 'characteristic density' to produce a state diagram that is relevant to experimental optical lattice systems, regardless of the number of bosons or trap curvature and of the validity of the local-density approximation. We show that the critical value of U/t at which Mott insulating domains appear in the trap depends on the filling in the system, and it is in general greater than the value in the homogeneous system. Recent experimental results by Spielman et al. [Phys. Rev. Lett. 100, 120402 (2008)] are analyzed in the context of our two-dimensional state diagram, and shown to exhibit a value for the critical point in good agreement with simulations. We also study the effects of finite, but low (T{<=}t/2), temperatures. We find that in two dimensions they have little influence on our zero-temperature results, while their effect is more pronounced in one dimension.

  5. The Kohn-Luttinger mechanism and phase diagram of the superconducting state in the Shubin-Vonsovsky model

    SciTech Connect

    Kagan, M. Yu.; Val'kov, V. V.; Mitskan, V. A.; Korovuskin, M. M.

    2013-10-15

    Using the Shubin-Vonsovsky model in the weak-coupling regime W > U > V (W is the bandwidth, U is the Hubbard onsite repulsion, and V is the Coulomb interaction at neighboring sites) based on the Kohn-Luttinger mechanism, we determined the regions of the existence of the superconducting phases with the d{sub xy}, p, s, and d{sub x{sup 2}-y{sup 2}} symmetry types of the order parameter. It is shown that the effective interaction in the Cooper channel considerably depends not only on single-site but also on intersite Coulomb correlations. This is demonstrated by the example of the qualitative change and complication of the phase diagram of the superconducting state. The superconducting (SC) phase induction mechanism is determined taking into account polarization contributions in the second-order perturbation theory in the Coulomb interaction. The results obtained for the angular dependence of the superconducting gap in different channels are compared with angule-resolved photoemission spectroscopy (ARPES) results. The influence of long-range hops in the phase diagram and critical superconducting transition temperature in different channels is analyzed. The conditions for the appearance of the Kohn-Luttinger superconductivity with the d{sub x{sup 2}-y{sup 2}} symmetry and high critical temperatures T{sub c} {approx} 100 K near the half-filling are determined.

  6. Flow diagram analysis of electrical fatalities in construction industry.

    PubMed

    Chi, Chia-Fen; Lin, Yuan-Yuan; Ikhwan, Mohamad

    2012-01-01

    The current study reanalyzed 250 electrical fatalities in the construction industry from 1996 to 2002 into seven patterns based on source of electricity (power line, energized equipment, improperly installed or damaged equipment), direct contact or indirect contact through some source of injury (boom vehicle, metal bar or pipe, and other conductive material). Each fatality was coded in terms of age, company size, experience, performing tasks, source of injury, accident cause and hazard pattern. The Chi-square Automatic Interaction Detector (CHAID) was applied to the coded data of the fatal electrocution to find a subset of predictors that might derive meaningful classifications or accidents scenarios. A series of Flow Diagrams was constructed based on CHAID result to illustrate the flow of electricity travelling from electrical source to human body. Each of the flow diagrams can be directly linked with feasible prevention strategies by cutting the flow of electricity. PMID:22317293

  7. Size Dependent Phase Diagrams of Nickel-Carbon Nanoparticles.

    PubMed

    Magnin, Y; Zappelli, A; Amara, H; Ducastelle, F; Bichara, C

    2015-11-13

    The carbon rich phase diagrams of nickel-carbon nanoparticles, relevant to catalysis and catalytic chemical vapor deposition synthesis of carbon nanotubes, are calculated for system sizes up to about 3 nm (807 Ni atoms). A tight binding model for interatomic interactions drives the grand canonical Monte Carlo simulations used to locate solid, core shell and liquid stability domains, as a function of size, temperature, and carbon chemical potential or concentration. Melting is favored by carbon incorporation from the nanoparticle surface, resulting in a strong relative lowering of the eutectic temperature and a phase diagram topology different from the bulk one. This should lead to a better understanding of the nanotube growth mechanisms. PMID:26613451

  8. Flow diagram analysis of electrical fatalities in construction industry.

    PubMed

    Chi, Chia-Fen; Lin, Yuan-Yuan; Ikhwan, Mohamad

    2012-01-01

    The current study reanalyzed 250 electrical fatalities in the construction industry from 1996 to 2002 into seven patterns based on source of electricity (power line, energized equipment, improperly installed or damaged equipment), direct contact or indirect contact through some source of injury (boom vehicle, metal bar or pipe, and other conductive material). Each fatality was coded in terms of age, company size, experience, performing tasks, source of injury, accident cause and hazard pattern. The Chi-square Automatic Interaction Detector (CHAID) was applied to the coded data of the fatal electrocution to find a subset of predictors that might derive meaningful classifications or accidents scenarios. A series of Flow Diagrams was constructed based on CHAID result to illustrate the flow of electricity travelling from electrical source to human body. Each of the flow diagrams can be directly linked with feasible prevention strategies by cutting the flow of electricity.

  9. The Influence of Gene–Environment Interactions on the Development of Alcoholism and Drug Dependence

    PubMed Central

    2012-01-01

    Alcoholism and drug dependence are common psychiatric disorders with a heritability of about 50%; therefore genetic and environmental influences are equally important. Early-life stress is a predictor of adolescent problem drinking/drug use and alcohol/drug dependence in adulthood, but moderating factors governing the availability of alcohol/drug are important. The risk–resilience balance for addiction may be due in part to the interaction between genetic variation and environment stressors (G×E); this has been confirmed by twin studies of inferred genetic risk. Measured genotype studies to detect G×E effects have used a range of alcohol consumption and diagnostic phenotypes and stressors ranging from early-life to adulthood past year life events. In this article, the current state of the field is critically reviewed and suggestions are put forth for future research. PMID:22367454

  10. Functional trait differences influence neighbourhood interactions in a hyperdiverse Amazonian forest.

    PubMed

    Fortunel, Claire; Valencia, Renato; Wright, S Joseph; Garwood, Nancy C; Kraft, Nathan J B

    2016-09-01

    As distinct community assembly processes can produce similar community patterns, assessing the ecological mechanisms promoting coexistence in hyperdiverse rainforests remains a considerable challenge. We use spatially explicit neighbourhood models of tree growth to quantify how functional trait and phylogenetic similarities predict variation in growth and crowding effects for the 315 most abundant tree species in a 25-ha lowland rainforest plot in Ecuador. We find that functional trait differences reflect variation in (1) species maximum potential growth, (2) the intensity of interspecific interactions for some species, and (3) species sensitivity to neighbours. We find that neighbours influenced tree growth in 28% of the 315 focal tree species. Neighbourhood effects are not detected in the remaining 72%, which may reflect the low statistical power to model rare taxa and/or species insensitivity to neighbours. Our results highlight the spectrum of ways in which functional trait differences can shape community dynamics in highly diverse rainforests. PMID:27358248

  11. The influence of autologous cell interactions on spontaneous and pokeweed mitogen-induced immunoglobulin production

    SciTech Connect

    Beale, M.G.

    1985-05-01

    Both helper- and suppressor-T-cell activities are generated in the autologous mixed lymphocyte reaction and in pokeweed mitogen (PWM)-stimulated cultures. The addition of low numbers of irradiated non-T cells enhance while high numbers suppress spontaneous and PWM-stimulated IgG synthesis by autologous cells. Monocytes are the principal inducers of suppression and exert their influence within the first 24 hr of culture. Suppression in association with PWM stimulation is nonspecific in nature, T-cell mediated, partially radiosensitive, and resistant to hydrocortisone. Neither indomethacin nor dibutyryl cyclic AMP reverses monocyte-related suppression. These findings suggest that the outcome of in vitro Ig synthesis assays is critically dependent upon monocyte-T-cell interaction.

  12. Amphiphilic drug interactions with model cellular membranes are influenced by lipid chain-melting temperature

    PubMed Central

    Casey, Duncan; Charalambous, Kalypso; Gee, Antony; Law, Robert V.; Ces, Oscar

    2014-01-01

    Small-molecule amphiphilic species such as many drug molecules frequently exhibit low-to-negligible aqueous solubility, and generally have no identified transport proteins assisting their distribution, yet are able to rapidly penetrate significant distances into patient tissue and even cross the blood–brain barrier. Previous work has identified a mechanism of translocation driven by acid-catalysed lipid hydrolysis of biological membranes, a process which is catalysed by the presence of cationic amphiphilic drug molecules. In this study, the interactions of raclopride, a model amphiphilic drug, were investigated with mixtures of biologically relevant lipids across a range of compositions, revealing the influence of the chain-melting temperature of the lipids upon the rate of acyl hydrolysis. PMID:24621813

  13. Influence of hydroxylation and glycosylation in ring A of soybean isoflavones on interaction with BSA.

    PubMed

    Zhao, Jinyao; Ren, Fenglian

    2009-04-01

    In this paper, the influence of hydroxylation and glycosylation of soybean isoflavones in ring A on the interaction with BSA was investigated. Two soybean isoflavone aglycones (daidzein and genistein) and their glycosides (daidzin and genistin) were used to study their ability to bind BSA by quenching the BSA intrinsic fluorescence in solution. The hydroxylation and glycosylation of soybean isoflavones in ring A significantly affected the binding/quenching process; in general, the hydroxylation increases the binding affinity and the glycosylation decreased the binding affinity. For daidzein and daidzin, the binding constants for BSA were 5.2 x 10(4) and 5.58 x 10(3) L mol(-1), respectively. For genistein and genistin, the binding constants were 8.40 x 10(5) and 1.44 x 10(5) L mol(-1), respectively. PMID:19112046

  14. A Hubble Diagram for Quasars

    NASA Astrophysics Data System (ADS)

    Risaliti, G.; Lusso, E.

    2015-12-01

    We present a new method to test the ΛCDM cosmological model and to estimate cosmological parameters based on the nonlinear relation between the ultraviolet and X-ray luminosities of quasars. We built a data set of 1138 quasars by merging several samples from the literature with X-ray measurements at 2 keV and SDSS photometry, which was used to estimate the extinction-corrected 2500 Å flux. We obtained three main results: (1) we checked the nonlinear relation between X-ray and UV luminosities in small redshift bins up to z˜ 6, confirming that the relation holds at all redshifts with the same slope; (2) we built a Hubble diagram for quasars up to z˜ 6, which is well matched to that of supernovae in the common z = 0-1.4 redshift interval and extends the test of the cosmological model up to z˜ 6; and (3) we showed that this nonlinear relation is a powerful tool for estimating cosmological parameters. Using the present data and assuming a ΛCDM model, we obtain {{{Ω }}}M = 0.22{}-0.08+0.10 and {{{Ω }}}{{Λ }} = 0.92{}-0.30+0.18 ({{{Ω }}}M = 0.28 ± 0.04 and {{{Ω }}}{{Λ }} = 0.73 +/- 0.08 from a joint quasar-SNe fit). Much more precise measurements will be achieved with future surveys. A few thousand SDSS quasars already have serendipitous X-ray observations from Chandra or XMM-Newton, and at least 100,000 quasars with UV and X-ray data will be made available by the extended ROentgen Survey with an Imaging Telescope Array all-sky survey in a few years. The Euclid, Large Synoptic Survey Telescope, and Advanced Telescope for High ENergy Astrophysics surveys will further increase the sample size to at least several hundred thousand. Our simulations show that these samples will provide tight constraints on the cosmological parameters and will allow us to test for possible deviations from the standard model with higher precision than is possible today.

  15. Virial expansion with Feynman diagrams

    SciTech Connect

    Leyronas, X.

    2011-11-15

    We present a field theoretic method for the calculation of the second and third virial coefficients b{sub 2} and b{sub 3} of two-species fermions interacting via a contact interaction. The method is mostly analytic. We find a closed expression for b{sub 3} in terms of the two- and three-body T matrices. We recover numerically, at unitarity, and also in the whole Bose-Einstein-condensate-BCS crossover, previous numerical results for the third virial coefficient b{sub 3}.

  16. Managing uncertainty in collaborative robotics engineering projects: The influence of task structure and peer interaction

    NASA Astrophysics Data System (ADS)

    Jordan, Michelle

    Uncertainty is ubiquitous in life, and learning is an activity particularly likely to be fraught with uncertainty. Previous research suggests that students and teachers struggle in their attempts to manage the psychological experience of uncertainty and that students often fail to experience uncertainty when uncertainty may be warranted. Yet, few educational researchers have explicitly and systematically observed what students do, their behaviors and strategies, as they attempt to manage the uncertainty they experience during academic tasks. In this study I investigated how students in one fifth grade class managed uncertainty they experienced while engaged in collaborative robotics engineering projects, focusing particularly on how uncertainty management was influenced by task structure and students' interactions with their peer collaborators. The study was initiated at the beginning of instruction related to robotics engineering and preceded through the completion of several long-term collaborative robotics projects, one of which was a design project. I relied primarily on naturalistic observation of group sessions, semi-structured interviews, and collection of artifacts. My data analysis was inductive and interpretive, using qualitative discourse analysis techniques and methods of grounded theory. Three theoretical frameworks influenced the conception and design of this study: community of practice, distributed cognition, and complex adaptive systems theory. Uncertainty was a pervasive experience for the students collaborating in this instructional context. Students experienced uncertainty related to the project activity and uncertainty related to the social system as they collaborated to fulfill the requirements of their robotics engineering projects. They managed their uncertainty through a diverse set of tactics for reducing, ignoring, maintaining, and increasing uncertainty. Students experienced uncertainty from more different sources and used more and

  17. Environmental conditions and biotic interactions influence ecosystem structure and function in a drying stream

    USGS Publications Warehouse

    Ludlam, J.P.; Magoulick, D.D.

    2010-01-01

    Benthic consumers influence stream ecosystem structure and function, but these interactions depend on environmental context. We experimentally quantified the effects of central stoneroller minnows (Campostoma anomalum (Rafinesque) and Meek's crayfish (Orconectes meeki meeki (Faxon)) on benthic communities using electric exclusion quadrats in Little Mulberry Creek before (June) and during (August) seasonal stream drying. Unglazed ceramic tiles were deployed in June and August to measure periphyton and invertebrate abundance, and leafpack decomposition and primary production were also measured in August. Relationships between stoneroller and crayfish density and the size of consumer effects were evaluated with multiple linear regression models. Average chlorophyll a abundance was greater on exposed than exclusion tiles in August, but not in June. Sediment dry mass, periphyton ash-free dry mass (AFDM), and chironomid densities on tiles did not differ among treatments in either period. Leaf packs decayed faster in exposed than exclusion treatments (kexposed = 0.038 ?? 0.013, kexclusion = 0.007 ?? 0.002), but consumer effects were stronger in some pools than others. Leafpack invertebrate biomass and abundance and tile primary productivity did not differ among treatments. Consumer effects on chlorophyll a were related to crayfish and stoneroller density, and effects on chironomid density were related to stoneroller density. These results contrast with a previous exclusion experiment in Little Mulberry Creek that demonstrated strong consumer effects. The influence of stream drying on consumer effects appears to have been reduced by strong spates, underscoring the importance of conducting multi-year studies to determine the magnitude of variability in ecological interactions. ?? US Government: USGS 2010.

  18. Influence of the interactions between tea (Camellia sinensis) extracts and ascorbic acid on their antioxidant activity: analysis with interaction indexes and isobolograms.

    PubMed

    Enko, Jolanta; Gliszczyńska-Świgło, Anna

    2015-01-01

    Products containing natural additives, including antioxidants, are usually perceived by consumers as safer than those with synthetic ones. Natural antioxidants, besides having a preservative activity, may exert beneficial health effects. Interactions between antioxidants may significantly change their antioxidant activity, thus in designing functional foods or food/cosmetic ingredients knowledge about the type of interactions could be useful. In the present study, the interactions between ascorbic acid (AA; vitamin C) and different black and green tea extracts and the influence on their antioxidant activities were investigated. The antioxidant activities of tea extracts and their mixtures with AA prepared in several different weight ratios were measured using the trolox equivalent antioxidant capacity (TEAC), 1,1-diphenyl-2-picrylhydrazyl (DPPH), and ferric-reducing antioxidant power (FRAP) methods. The type of interaction was determined by interaction indexes and isobolograms. It was found that the weight ratio of extracts to AA significantly influenced the antioxidant activity of a mixture and the type of interaction between these components. The weight ratio of tea extract to AA can cause the change of interaction, e.g. from antagonism to additivism or from additivism to synergism. The observed differences in the type of interactions were probably also a result of different extracts' polyphenol composition and content. The type of interaction may also be affected by the medium in which extracts and AA interact, especially its pH and the solvent used. To obtain the best antioxidant effect, all these factors should be taken into account during the design of a tea extract-AA mixture. PMID:26035225

  19. Influence of the interactions between tea (Camellia sinensis) extracts and ascorbic acid on their antioxidant activity: analysis with interaction indexes and isobolograms.

    PubMed

    Enko, Jolanta; Gliszczyńska-Świgło, Anna

    2015-01-01

    Products containing natural additives, including antioxidants, are usually perceived by consumers as safer than those with synthetic ones. Natural antioxidants, besides having a preservative activity, may exert beneficial health effects. Interactions between antioxidants may significantly change their antioxidant activity, thus in designing functional foods or food/cosmetic ingredients knowledge about the type of interactions could be useful. In the present study, the interactions between ascorbic acid (AA; vitamin C) and different black and green tea extracts and the influence on their antioxidant activities were investigated. The antioxidant activities of tea extracts and their mixtures with AA prepared in several different weight ratios were measured using the trolox equivalent antioxidant capacity (TEAC), 1,1-diphenyl-2-picrylhydrazyl (DPPH), and ferric-reducing antioxidant power (FRAP) methods. The type of interaction was determined by interaction indexes and isobolograms. It was found that the weight ratio of extracts to AA significantly influenced the antioxidant activity of a mixture and the type of interaction between these components. The weight ratio of tea extract to AA can cause the change of interaction, e.g. from antagonism to additivism or from additivism to synergism. The observed differences in the type of interactions were probably also a result of different extracts' polyphenol composition and content. The type of interaction may also be affected by the medium in which extracts and AA interact, especially its pH and the solvent used. To obtain the best antioxidant effect, all these factors should be taken into account during the design of a tea extract-AA mixture.

  20. Follow the heart or the head? The interactive influence model of emotion and cognition.

    PubMed

    Luo, Jiayi; Yu, Rongjun

    2015-01-01

    The experience of emotion has a powerful influence on daily-life decision making. Following Plato's description of emotion and reason as two horses pulling us in opposite directions, modern dual-system models of decision making endorse the antagonism between reason and emotion. Decision making is perceived as the competition between an emotion system that is automatic but prone to error and a reason system that is slow but rational. The reason system (in "the head") reins in our impulses (from "the heart") and overrides our snap judgments. However, from Darwin's evolutionary perspective, emotion is adaptive, guiding us to make sound decisions in uncertainty. Here, drawing findings from behavioral economics and neuroeconomics, we provide a new model, labeled "The interactive influence model of emotion and cognition," to elaborate the relationship of emotion and reason in decision making. Specifically, in our model, we identify factors that determine when emotions override reason and delineate the type of contexts in which emotions help or hurt decision making. We then illustrate how cognition modulates emotion and how they cooperate to affect decision making. PMID:25999889

  1. Patterns in soil fertility and root herbivory interact to influence fine-root dynamics.

    PubMed

    Stevens, Glen N; Jones, Robert H

    2006-03-01

    Fine-scale soil nutrient enrichment typically stimulates root growth, but it may also increase root herbivory, resulting in trade-offs for plant species and potentially influencing carbon cycling patterns. We used root ingrowth cores to investigate the effects of microsite fertility and root herbivory on root biomass in an aggrading upland forest in the coastal plain of South Carolina, USA. Treatments were randomly assigned to cores from a factorial combination of fertilizer and insecticide. Soil, soil fauna, and roots were removed from the cores at the end of the experiment (8-9 mo), and roots were separated at harvest into three diameter classes. Each diameter class responded differently to fertilizer and insecticide treatments. The finest roots (< 1.0 mm diameter), which comprised well over half of all root biomass, were the only ones to respond significantly to both treatments, increasing when fertilizer and when insecticide were added (each P < 0.0001), with maximum biomass found where the treatments were combined (interaction term significant, P < 0.001). These results suggest that root-feeding insects have a strong influence on root standing crop with stronger herbivore impacts on finer roots and within more fertile microsites. Thus, increased vulnerability to root herbivory is a potentially significant cost of root foraging in nutrient-rich patches.

  2. The influence of interactional semantic patterns on the interpretation of noun-noun compounds.

    PubMed

    Maguire, Phil; Maguire, Rebecca; Cater, Arthur W S

    2010-03-01

    The CARIN theory (C. L. Gagné & E. J. Shoben, 1997) proposes that people use statistical knowledge about the relations with which modifiers are typically used to facilitate the interpretation of modifier-noun combinations. However, research on semantic patterns in compounding has suggested that regularities tend to be associated with pairings of semantic categories, rather than individual concepts (e.g., P. Maguire, E. J. Wisniewski, & G. Storms, in press; B. Warren, 1978). In the present study, the authors investigated whether people are sensitive to interactional semantic patterns in compounding. Experiment 1 demonstrated that the influence of a given modifier on ease of interpretation varies depending on the semantic category of the head. Experiment 2 demonstrated that the relation preference of the head noun influences ease of interpretation when the semantic category of the modifier is compatible with that preference. In light of these findings, the authors suggest that people are sensitive to how different semantic categories tend to be paired in combination and that this information is used to facilitate the interpretation process. PMID:20192532

  3. Follow the heart or the head? The interactive influence model of emotion and cognition

    PubMed Central

    Luo, Jiayi; Yu, Rongjun

    2015-01-01

    The experience of emotion has a powerful influence on daily-life decision making. Following Plato’s description of emotion and reason as two horses pulling us in opposite directions, modern dual-system models of decision making endorse the antagonism between reason and emotion. Decision making is perceived as the competition between an emotion system that is automatic but prone to error and a reason system that is slow but rational. The reason system (in “the head”) reins in our impulses (from “the heart”) and overrides our snap judgments. However, from Darwin’s evolutionary perspective, emotion is adaptive, guiding us to make sound decisions in uncertainty. Here, drawing findings from behavioral economics and neuroeconomics, we provide a new model, labeled “The interactive influence model of emotion and cognition,” to elaborate the relationship of emotion and reason in decision making. Specifically, in our model, we identify factors that determine when emotions override reason and delineate the type of contexts in which emotions help or hurt decision making. We then illustrate how cognition modulates emotion and how they cooperate to affect decision making. PMID:25999889

  4. Follow the heart or the head? The interactive influence model of emotion and cognition.

    PubMed

    Luo, Jiayi; Yu, Rongjun

    2015-01-01

    The experience of emotion has a powerful influence on daily-life decision making. Following Plato's description of emotion and reason as two horses pulling us in opposite directions, modern dual-system models of decision making endorse the antagonism between reason and emotion. Decision making is perceived as the competition between an emotion system that is automatic but prone to error and a reason system that is slow but rational. The reason system (in "the head") reins in our impulses (from "the heart") and overrides our snap judgments. However, from Darwin's evolutionary perspective, emotion is adaptive, guiding us to make sound decisions in uncertainty. Here, drawing findings from behavioral economics and neuroeconomics, we provide a new model, labeled "The interactive influence model of emotion and cognition," to elaborate the relationship of emotion and reason in decision making. Specifically, in our model, we identify factors that determine when emotions override reason and delineate the type of contexts in which emotions help or hurt decision making. We then illustrate how cognition modulates emotion and how they cooperate to affect decision making.

  5. PATTERNS IN SOIL FERTILITY AND ROOT HERBIVORY INTERACT TO INFLUENCE FINE-ROOT DYNAMICS.

    SciTech Connect

    Stevens, Glen, N.; Jones, Robert, H.

    2006-03-01

    Fine-scale soil nutrient enrichment typically stimulates root growth, but it may also increase root herbivory, resulting in trade-offs for plant species and potentially influencing carbon cycling patterns. We used root ingrowth cores to investigate the effects of microsite fertility and root herbivory on root biomass in an aggrading upland forest in the coastal plain of South Carolina, USA. Treatments were randomly assigned to cores from a factorial combination of fertilizer and insecticide. Soil, soil fauna, and roots were removed from the cores at the end of the experiment (8–9 mo), and roots were separated at harvest into three diameter classes. Each diameter class responded differently to fertilizer and insecticide treatments. The finest roots (,1.0 mm diameter), which comprised well over half of all root biomass, were the only ones to respond significantly to both treatments, increasing when fertilizer and when insecticide were added (each P , 0.0001), with maximum biomass found where the treatments were combined (interaction term significant, P , 0.001). These results suggest that root-feeding insects have a strong influence on root standing crop with stronger herbivore impacts on finer roots and within more fertile microsites. Thus, increased vulnerability to root herbivory is a potentially significant cost of root foraging in nutrient-rich patches.

  6. Influence of nuclear interactions in body tissues on tumor dose in carbon-ion radiotherapy

    SciTech Connect

    Inaniwa, T. Kanematsu, N.; Tsuji, H.; Kamada, T.

    2015-12-15

    Purpose: In carbon-ion radiotherapy treatment planning, the planar integrated dose (PID) measured in water is applied to the patient dose calculation with density scaling using the stopping power ratio. Since body tissues are chemically different from water, this dose calculation can be subject to errors, particularly due to differences in inelastic nuclear interactions. In recent studies, the authors proposed and validated a PID correction method for these errors. In the present study, the authors used this correction method to assess the influence of these nuclear interactions in body tissues on tumor dose in various clinical cases. Methods: Using 10–20 cases each of prostate, head and neck (HN), bone and soft tissue (BS), lung, liver, pancreas, and uterine neoplasms, the authors first used treatment plans for carbon-ion radiotherapy without nuclear interaction correction to derive uncorrected dose distributions. The authors then compared these distributions with recalculated distributions using the nuclear interaction correction (corrected dose distributions). Results: Median (25%/75% quartiles) differences between the target mean uncorrected doses and corrected doses were 0.2% (0.1%/0.2%), 0.0% (0.0%/0.0%), −0.3% (−0.4%/−0.2%), −0.1% (−0.2%/−0.1%), −0.1% (−0.2%/0.0%), −0.4% (−0.5%/−0.1%), and −0.3% (−0.4%/0.0%) for the prostate, HN, BS, lung, liver, pancreas, and uterine cases, respectively. The largest difference of −1.6% in target mean and −2.5% at maximum were observed in a uterine case. Conclusions: For most clinical cases, dose calculation errors due to the water nonequivalence of the tissues in nuclear interactions would be marginal compared to intrinsic uncertainties in treatment planning, patient setup, beam delivery, and clinical response. In some extreme cases, however, these errors can be substantial. Accordingly, this correction method should be routinely applied to treatment planning in clinical practice.

  7. The influence of source-receiver interaction on the numerical prediction of railway induced vibrations

    NASA Astrophysics Data System (ADS)

    Coulier, P.; Lombaert, G.; Degrande, G.

    2014-06-01

    The numerical prediction of vibrations in buildings due to railway traffic is a complicated problem where wave propagation in the soil couples the source (railway tunnel or track) and the receiver (building). This through-soil coupling is often neglected in state-of-the-art numerical models in order to reduce the computational cost. In this paper, the effect of this simplifying assumption on the accuracy of numerical predictions is investigated. A coupled finite element-boundary element methodology is employed to analyze the interaction between a building and a railway tunnel at depth or a ballasted track at the surface of a homogeneous halfspace, respectively. Three different soil types are considered. It is demonstrated that the dynamic axle loads can be calculated with reasonable accuracy using an uncoupled strategy in which through-soil coupling is disregarded. If the transfer functions from source to receiver are considered, however, large local variations in terms of vibration insertion gain are induced by source-receiver interaction, reaching up to 10 dB and higher, although the overall wave field is only moderately affected. A global quantification of the significance of through-soil coupling is made, based on the mean vibrational energy entering a building. This approach allows assessing the common assumption in seismic engineering that source-receiver interaction can be neglected if the distance between source and receiver is sufficiently large compared to the wavelength of waves in the soil. It is observed that the interaction between a source at depth and a receiver mainly affects the power flow distribution if the distance between source and receiver is smaller than the dilatational wavelength in the soil. Interaction effects for a railway track at grade are observed if the source-receiver distance is smaller than six Rayleigh wavelengths. A similar trend is revealed if the passage of a freight train is considered. The overall influence of dynamic

  8. Complex contextual influences on the communicative interactions of students with multiple and severe disabilities.

    PubMed

    De Bortoli, Tania; Arthur-Kelly, Michael; Foreman, Phil; Balandin, Susan; Mathisen, Bernice

    2011-10-01

    The aim of this study was to explore teachers' perceptions and experiences of supports and obstacles to engaging students with multiple and severe disabilities (MSD) in communicative interactions at school. Eleven teachers of students with MSD participated in two in-depth interviews. Interview transcripts were analysed for narrative structure and content themes. Inter-coder reliability for coding of content themes was 87.5%. Participants identified a broad range of factors, including: characteristics of individual students, attitudes, perceptions and beliefs of teachers and other staff, class structure, staffing, opportunities for collegiality, resources, funding, infrastructure, collaboration with speech-language pathologists, appropriate communication education for teachers, the role of government departments, and broader societal factors. The findings suggest that there are complex contextual influences on the communicative interactions of students with MSD. While inadequate systemic supports appear to contribute to low frequencies of communication, systemic factors can be structured so that students participate in activities and have opportunities for communication. Further research is required with teachers of students with MSD to substantiate these findings.

  9. Relative Cosolute Size Influences the Kinetics of Protein-Protein Interactions.

    PubMed

    Hoffman, Laurel; Wang, Xu; Sanabria, Hugo; Cheung, Margaret S; Putkey, John A; Waxham, M Neal

    2015-08-01

    Protein signaling occurs in crowded intracellular environments, and while high concentrations of macromolecules are postulated to modulate protein-protein interactions, analysis of their impact at each step of the reaction pathway has not been systematically addressed. Potential cosolute-induced alterations in target association are particularly important for a signaling molecule like calmodulin (CaM), where competition among >300 targets governs which pathways are selectively activated. To explore how high concentrations of cosolutes influence CaM-target affinity and kinetics, we methodically investigated each step of the CaM-target binding mechanism under crowded or osmolyte-rich environments mimicked by ficoll-70, dextran-10, and sucrose. All cosolutes stabilized compact conformers of CaM and modulated association kinetics by affecting diffusion and rates of conformational change; however, the results showed that differently sized molecules had variable effects to enhance or impede unique steps of the association pathway. On- and off-rates were modulated by all cosolutes in a compensatory fashion, producing little change in steady-state affinity. From this work insights were gained on how high concentrations of inert crowding agents and osmolytes fit into a kinetic framework to describe protein-protein interactions relevant for cellular signaling. PMID:26244733

  10. Flavor release and perception in hard candy: influence of flavor compound-compound interactions.

    PubMed

    Schober, Amanda L; Peterson, Devin G

    2004-05-01

    The influence of flavor compound-compound interactions on flavor release properties and flavor perception in hard candy was investigated. Hard candies made with two different modes of binary flavor delivery, (1) L-menthol and 1,8-cineole added as a mixture and (2) L-menthol and 1,8-cineole added separate from one another, were analyzed via breath analysis and sensory time-intensity testing. Single-flavor candy containing only L-menthol or 1,8-cineole was also investigated via breath analysis for comparison. The release rates of both L-menthol and 1,8-cineole in the breath were more rapid and at a higher concentration when the compounds were added to hard candy separate from one another in comparison to their addition as a mixture (conventional protocol). Additionally, the time-intensity study indicated a significantly increased flavor intensity (measured as overall cooling) for hard candy made with separate addition of these flavor compounds. In conclusion, the flavor properties of hard candy can be controlled, at least in part, by flavor compound-compound interactions and may be altered by the method of flavor delivery.

  11. Influence of plant-earthworm interactions on SOM chemistry and p,p'-DDE bioaccumulation.

    PubMed

    Kelsey, Jason W; Slizovskiy, Ilya B; Petriello, Michael C; Butler, Kelly L

    2011-05-01

    Laboratory experiments assessed how bioaccumulation of weathered p,p'-DDE from soil and humic acid (HA) chemistry are affected by interactions between the plants Cucurbita pepo ssp. pepo and ssp. ovifera and the earthworms Eisenia fetida, Lumbricus terrestris, and Apporectodea caliginosa. Total organochlorine phytoextraction by ssp. pepo increased at least 25% in the presence of any of the earthworm species (relative to plants grown in isolation). Uptake of the compound by ssp. ovifera was unaffected by earthworms. Plants influenced earthworm bioaccumulation as well. When combined with pepo, p,p'-DDE levels in E. fetida decreased by 50%, whereas, in the presence of ovifera, bioconcentration by L. terrestris increased by more than 2-fold. Spectral analysis indicated a decrease in hydrophobicity of HA in each of the soils in which both pepo and earthworms were present. However, HA chemistry from ovifera treatments was largely unaffected by earthworms. Risk assessments of contaminated soils should account for species interactions, and SOM chemistry may be a useful indictor of pollutant bioaccumulation. PMID:21421253

  12. Interaction between sex and early-life stress: influence on epileptogenesis and epilepsy comorbidities.

    PubMed

    Jones, Nigel C; O'Brien, Terence J; Carmant, Lionel

    2014-12-01

    Epilepsy is a common brain disorder which is characterised by recurring seizures. In addition to suffering from the constant stress of living with this neurological condition, patients also frequently experience comorbid psychiatric and cognitive disorders which significantly impact their quality of life. There is growing appreciation that stress, in particular occurring in early life, can negatively impact brain development, creating an enduring vulnerability to develop epilepsy. This aligns with the solid connections between early life environments and the development of psychiatric conditions, promoting the possibility that adverse early life events could represent a common risk factor for the later development of both epilepsy and comorbid psychiatric disorders. The influence of sex has been little studied, but recent research points to potential important interactions, particularly with regard to effects mediated by HPA axis programming. Understanding these interactions, and the underlying molecular mechanisms, will provide important new insights into the causation of both epilepsy and of psychiatric disorders, and potentially open up novel avenues for treatment.

  13. Influence of interactions between genes and childhood trauma on refractoriness in psychiatric disorders.

    PubMed

    Kim, Ji Sun; Lee, Seung-Hwan

    2016-10-01

    Psychiatric disorders are excellent disease models in which gene-environmental interaction play a significant role in the pathogenesis. Childhood trauma has been known as a significant environmental factor in the progress of, and prognosis for psychiatric illness. Patients with refractory illness usually have more severe symptoms, greater disability, lower quality of life and are at greater risk of suicide than other psychiatric patients. Our literature review uncovered some important clinical factors which modulate response to treatment in psychiatric patients who have experienced childhood trauma. Childhood trauma seems to be a critical determinant of treatment refractoriness in psychotic disorder, bipolar disorder, major depressive disorder, and post-traumatic stress disorder. In patients with psychotic disorders, the relationship between childhood trauma and treatment-refractoriness appears to be mediated by cognitive impairment. In the case of bipolar disorder, the relationship appears to be mediated by greater affective disturbance and earlier onset, while in major depressive disorder the mediating factors are persistent, severe symptoms and frequent recurrence. In suicidal individuals, childhood maltreatment was associated with violent suicidal attempts. In the case of PTSD patients, it appears that childhood trauma makes the brain more vulnerable to subsequent trauma, thus resulting in more severe, refractory symptoms. Given that several studies have suggested that there are distinct subtypes of genetic vulnerability to childhood trauma, it is important to understand how gene-environment interactions influence the course of psychiatric illnesses in order to improve therapeutic strategies.

  14. Factors influencing gastrointestinal tract and microbiota immune interaction in preterm infants.

    PubMed

    Collado, María Carmen; Cernada, María; Neu, Josef; Pérez-Martínez, Gaspar; Gormaz, María; Vento, Máximo

    2015-06-01

    The role of microbial colonization is indispensable for keeping a balanced immune response in life. However, the events that regulate the establishment of the microbiota, their timing, and the way in which they interact with the host are not yet fully understood. Factors such as gestational age, mode of delivery, environment, hygienic measures, and diet influence the establishment of microbiota in the perinatal period. Environmental microbes constitute the most important group of exogenous stimuli in this critical time frame. However, the settlement of a stable gut microbiota in preterm infants is delayed compared to term infants. Preterm infants have an immature gastrointestinal tract and immune system which predisposes to infectious morbidity. Neonatal microbial dynamics and alterations in early gut microbiota may precede and/or predispose to diseases such as necrotizing enterocolitis (NEC), late-onset sepsis or others. During this critical period, nutrition is the principal contributor for immunological and metabolic development, and microbiological programming. Breast milk is a known source of molecules that act synergistically to protect the gut barrier and enhance the maturation of the gut-related immune response. Host-microbe interactions in preterm infants and the protective role of diet focused on breast milk impact are beginning to be unveiled.

  15. Influence of interactions between genes and childhood trauma on refractoriness in psychiatric disorders.

    PubMed

    Kim, Ji Sun; Lee, Seung-Hwan

    2016-10-01

    Psychiatric disorders are excellent disease models in which gene-environmental interaction play a significant role in the pathogenesis. Childhood trauma has been known as a significant environmental factor in the progress of, and prognosis for psychiatric illness. Patients with refractory illness usually have more severe symptoms, greater disability, lower quality of life and are at greater risk of suicide than other psychiatric patients. Our literature review uncovered some important clinical factors which modulate response to treatment in psychiatric patients who have experienced childhood trauma. Childhood trauma seems to be a critical determinant of treatment refractoriness in psychotic disorder, bipolar disorder, major depressive disorder, and post-traumatic stress disorder. In patients with psychotic disorders, the relationship between childhood trauma and treatment-refractoriness appears to be mediated by cognitive impairment. In the case of bipolar disorder, the relationship appears to be mediated by greater affective disturbance and earlier onset, while in major depressive disorder the mediating factors are persistent, severe symptoms and frequent recurrence. In suicidal individuals, childhood maltreatment was associated with violent suicidal attempts. In the case of PTSD patients, it appears that childhood trauma makes the brain more vulnerable to subsequent trauma, thus resulting in more severe, refractory symptoms. Given that several studies have suggested that there are distinct subtypes of genetic vulnerability to childhood trauma, it is important to understand how gene-environment interactions influence the course of psychiatric illnesses in order to improve therapeutic strategies. PMID:26827636

  16. Relative Cosolute Size Influences the Kinetics of Protein-Protein Interactions

    PubMed Central

    Hoffman, Laurel; Wang, Xu; Sanabria, Hugo; Cheung, Margaret S.; Putkey, John A.; Waxham, M. Neal

    2015-01-01

    Protein signaling occurs in crowded intracellular environments, and while high concentrations of macromolecules are postulated to modulate protein-protein interactions, analysis of their impact at each step of the reaction pathway has not been systematically addressed. Potential cosolute-induced alterations in target association are particularly important for a signaling molecule like calmodulin (CaM), where competition among >300 targets governs which pathways are selectively activated. To explore how high concentrations of cosolutes influence CaM-target affinity and kinetics, we methodically investigated each step of the CaM-target binding mechanism under crowded or osmolyte-rich environments mimicked by ficoll-70, dextran-10, and sucrose. All cosolutes stabilized compact conformers of CaM and modulated association kinetics by affecting diffusion and rates of conformational change; however, the results showed that differently sized molecules had variable effects to enhance or impede unique steps of the association pathway. On- and off-rates were modulated by all cosolutes in a compensatory fashion, producing little change in steady-state affinity. From this work insights were gained on how high concentrations of inert crowding agents and osmolytes fit into a kinetic framework to describe protein-protein interactions relevant for cellular signaling. PMID:26244733

  17. BDNF Val66Met is Associated with Introversion and Interacts with 5-HTTLPR to Influence Neuroticism

    PubMed Central

    Terracciano, Antonio; Tanaka, Toshiko; Sutin, Angelina R; Deiana, Barbara; Balaci, Lenuta; Sanna, Serena; Olla, Nazario; Maschio, Andrea; Uda, Manuela; Ferrucci, Luigi; Schlessinger, David; Costa, Paul T

    2010-01-01

    Brain-derived neurotrophic factor (BDNF) regulates synaptic plasticity and neurotransmission, and has been linked to neuroticism, a major risk factor for psychiatric disorders. A recent genome-wide association (GWA) scan, however, found the BDNF Val66Met polymorphism (rs6265) associated with extraversion but not with neuroticism. In this study, we examine the links between BDNF and personality traits, assessed using the Revised NEO Personality Inventory (NEO-PI-R), in a sample from SardiNIA (n=1560) and the Baltimore Longitudinal Study of Aging (BLSA; n=1131). Consistent with GWA results, we found that BDNF Met carriers were more introverted. By contrast, in both samples and in a meta-analysis inclusive of published data (n=15251), we found no evidence for a main effect of BDNF Val66Met on neuroticism. Finally, on the basis of recent reports of an epistatic effect between BDNF and the serotonin transporter, we explored a Val66Met × 5-HTTLPR interaction in a larger SardiNIA sample (n=2333). We found that 5-HTTLPR LL carriers scored lower on neuroticism in the presence of the BDNF Val variant, but scored higher on neuroticism in the presence of the BDNF Met variant. Our findings support the association between the BDNF Met variant and introversion and suggest that BDNF interacts with the serotonin transporter gene to influence neuroticism. PMID:20042999

  18. Influence of wind and lake morphometry on the interaction between two rivers entering a stratified lake

    USGS Publications Warehouse

    Morillo, S.; Imberger, J.; Antenucci, J.P.; Woods, P.F.

    2008-01-01

    The interaction of two rivers flowing into Coeur d'Alene Lake (United States) was investigated with a field experiment and three-dimensional numerical simulations. The focus was on the influence of basin morphology, wind speed, and wind direction on the fate and transport of the inflowing water. Data from the field campaign showed that intrusions from the two rivers propagated into the lake at different depths, with the trace element polluted Coeur d'Alene River flowing into the lake above the trace element poor and nutrient rich St. Joe River inflow. The inflows initially intruded horizontally into the lake at their level of neutral buoyancy and later mixed vertically. Model results revealed that, as the intrusions entered the main lake basin, a forced horizontal mode-two basin-scale internal wave interacted with the intrusions to frequently siphon them into the lake proper and where rapid vertical mixing followed. The results serve to show how detailed transport and mixing patterns in a lake can have important consequences for the plankton ecology in the lake. ?? 2008 ASCE.

  19. The Art of Free-Body Diagrams.

    ERIC Educational Resources Information Center

    Puri, Avinash

    1996-01-01

    Discusses the difficulty of drawing free-body diagrams which only show forces exerted on a body from its neighbors. Presents three ways a body may be modeled: a particle, rigid extended, and nonrigid extended. (MKR)

  20. Phase diagram for passive electromagnetic scatterers.

    PubMed

    Lee, Jeng Yi; Lee, Ray-Kuang

    2016-03-21

    With the conservation of power, a phase diagram defined by amplitude square and phase of scattering coefficients for each spherical harmonic channel is introduced as a universal map for any passive electromagnetic scatterers. Physically allowable solutions for scattering coefficients in this diagram clearly show power competitions among scattering and absorption. It also illustrates a variety of exotic scattering or absorption phenomena, from resonant scattering, invisible cloaking, to coherent perfect absorber. With electrically small core-shell scatterers as an example, we demonstrate a systematic method to design field-controllable structures based on the allowed trajectories in this diagram. The proposed phase diagram and inverse design can provide tools to design functional electromagnetic devices. PMID:27136839

  1. An Improved Mnemonic Diagram for Thermodynamic Relationships.

    ERIC Educational Resources Information Center

    Rodriguez, Joaquin; Brainard, Alan J.

    1989-01-01

    Considers pressure, volume, entropy, temperature, Helmholtz free energy, Gibbs free energy, enthalpy, and internal energy. Suggests the mnemonic diagram is for use with simple systems that are defined as macroscopically homogeneous, isotropic, uncharged, and chemically inert. (MVL)

  2. Attribute Reduction Based on Property Pictorial Diagram

    PubMed Central

    Wan, Qing; Wei, Ling

    2014-01-01

    This paper mainly studies attribute reduction which keeps the lattice structure in formal contexts based on the property pictorial diagram. Firstly, the property pictorial diagram of a formal context is defined. Based on such diagram, an attribute reduction approach of concept lattice is achieved. Then, through the relation between an original formal context and its complementary context, an attribute reduct of complementary context concept lattice is obtained, which is also based on the property pictorial diagram of the original formal context. Finally, attribute reducts in property oriented concept lattice and object oriented concept lattice can be acquired by the relations of attribute reduction between these two lattices and concept lattice of complementary context. In addition, a detailed illustrative example is presented. PMID:25247200

  3. Time-dependent Benioff strain release diagrams

    NASA Astrophysics Data System (ADS)

    Frid, V.; Goldbaum, J.; Rabinovitch, A.; Bahat, D.

    2011-04-01

    New time-dependent Benioff strain (TDBS) release diagrams were analyzed for acoustic emission during various loading tests and for electromagnetic (EM) radiation emanating during compression and, tension, which end in failure. TDBS diagrams are Benioff diagrams that are built consecutively, each time using a greater number of events (acoustic or EM emissions) using the last event as if it were associated with the 'actual failure'. An examination of such TDBS diagrams shows that at a certain time point (this time point is denoted by the term 'alarm' time), a comparatively short interval prior to actual collapse, their decreasing part is broken by a positive 'bulge'. This 'bulge' is quantified and an algorithm proposed for its assessment. Using the alarm time and other parameters of the failure process (fall, bulge size and escalation factors, bulge slope and slope fall time), a criterion for estimating the time of the actual collapse is developed and shown to agree well with laboratory experimental results.

  4. Veitch diagram plotter simplifies Boolean functions

    NASA Technical Reports Server (NTRS)

    Rubin, D. K.

    1964-01-01

    This device for simplifying the plotting of a Veitch diagram consists of several overlays for blocking out the unwanted squares. This method of plotting the various input combinations to a computer is used in conjunction with the Boolean functions.

  5. Consequences of complex environments: Temperature and energy intake interact to influence growth and metabolic rate.

    PubMed

    Stahlschmidt, Zachary R; Jodrey, Alicia D; Luoma, Rachel L

    2015-09-01

    The field of comparative physiology has a rich history of elegantly examining the effects of individual environmental factors on performance traits linked to fitness (e.g., thermal performance curves for locomotion). However, animals live in complex environments wherein multiple environmental factors co-vary. Thus, we investigated the independent and interactive effects of temperature and energy intake on the growth and metabolic rate of juvenile corn snakes (Pantherophis guttatus) in the context of shifts in complex environments. Unlike previous studies that imposed constant or fluctuating temperature regimes, we manipulated the availability of preferred thermal microclimates (control vs. relatively warm regimes) for eight weeks and allowed snakes to behaviorally thermoregulate among microclimates. By also controlling for energy intake, we demonstrate an interactive effect of temperature and energy on growth-relevant temperature shifts had no effect on snakes' growth when energy intake was low and a positive effect on growth when energy intake was high. Thus, acclimation to relatively warm thermal options can result in increased rates of growth when food is abundant in a taxon in which body size confers fitness advantages. Temperature and energy also interactively influenced metabolic rate-snakes in the warmer temperature regime exhibited reduced metabolic rate (O2 consumption rate at 25 °C and 30 °C) if they had relatively high energy intake. Although we advocate for continued investigation into the effects of complex environments on other traits, our results indicate that warming may actually benefit important life history traits in some taxa and that metabolic shifts may underlie thermal acclimation. PMID:25899738

  6. Consequences of complex environments: Temperature and energy intake interact to influence growth and metabolic rate.

    PubMed

    Stahlschmidt, Zachary R; Jodrey, Alicia D; Luoma, Rachel L

    2015-09-01

    The field of comparative physiology has a rich history of elegantly examining the effects of individual environmental factors on performance traits linked to fitness (e.g., thermal performance curves for locomotion). However, animals live in complex environments wherein multiple environmental factors co-vary. Thus, we investigated the independent and interactive effects of temperature and energy intake on the growth and metabolic rate of juvenile corn snakes (Pantherophis guttatus) in the context of shifts in complex environments. Unlike previous studies that imposed constant or fluctuating temperature regimes, we manipulated the availability of preferred thermal microclimates (control vs. relatively warm regimes) for eight weeks and allowed snakes to behaviorally thermoregulate among microclimates. By also controlling for energy intake, we demonstrate an interactive effect of temperature and energy on growth-relevant temperature shifts had no effect on snakes' growth when energy intake was low and a positive effect on growth when energy intake was high. Thus, acclimation to relatively warm thermal options can result in increased rates of growth when food is abundant in a taxon in which body size confers fitness advantages. Temperature and energy also interactively influenced metabolic rate-snakes in the warmer temperature regime exhibited reduced metabolic rate (O2 consumption rate at 25 °C and 30 °C) if they had relatively high energy intake. Although we advocate for continued investigation into the effects of complex environments on other traits, our results indicate that warming may actually benefit important life history traits in some taxa and that metabolic shifts may underlie thermal acclimation.

  7. Interactions between fluvial forces and vegetation size, density and morphology influence plant mortality during experimental floods

    NASA Astrophysics Data System (ADS)

    Stella, J. C.; Kui, L.; Manners, R.; Wilcox, A. C.; Lightbody, A.; Sklar, L. S.

    2015-12-01

    Introduction and methods Fluvial disturbance is a key driver of riparian vegetation dynamics in river corridors. Despite an increasing understanding of ecohydraulic interactions between plants and fluvial forces, the interactive influences of plant morphology and sediment supply on plant mortality, a key demographic factor, are largely unknown. To better understand these processes, we designed and conducted a series of flume experiments to: (1) quantify effects of plant traits that interact with flow and sediment transport on plant loss to scour during floods; and (2) predict plant dislodgement for different species across a range of plant sizes, patch densities, and sediment condition (equilibrium transport versus sediment deficit). We ran ten experimental floods in a 28 m long × 0.6 m wide × 0.71 m tall flume, using live, 1-3 year-old tamarisk and cottonwood seedlings with contrasting morphologies with varied combinations of size and density. Results and discussion Both sediment supply and plant traits (morphology and composition) have significant impacts on plant vulnerability during floods. Sediment deficit resulted in bed degradation and a 35% greater risk of plant loss compared to equilibrium sediment conditions. The probability of plant dislodgement in sparse patches was 4.5 times greater than in dense patches. Tamarisk plants and patches had greater frontal area, basal diameter and longer roots compared to cottonwood across all seedling heights. These traits, as well as its lower crown position reduced tamarisk's vulnerability to scour by 75%. Compared with cottonwood, tamarisk exhibits better resistance to floods, due to its greater root biomass and longer roots that stabilize soil, and its greater frontal area and lower crown that effectively trap sediment. These traits likely contribute to riverscape-scale changes in channel morphology that are evident where tamarisk has invaded native riparian communities, and explain the persistence of tamarisk

  8. Composition of extrafloral nectar influences interactions between the myrmecophyte Humboldtia brunonis and its ant associates.

    PubMed

    Shenoy, Megha; Radhika, Venkatesan; Satish, Suma; Borges, Renee M

    2012-01-01

    Ant-plant interactions often are mediated by extrafloral nectar (EFN) composition that may influence plant visitation by ants. Over a 300 km range in the Indian Western Ghats, we investigated the correlation between the EFN composition of the myrmecophytic ant-plant Humboldtia brunonis (Fabaceae) and the number and species of ants visiting EFN. EFN composition varied among H. brunonis populations and between plant organs (floral bud vs. young leaf EFN). In general, EFN was rich in sugars with small quantities of amino acids, especially essential amino acids, and had moderate invertase activity. In experiments at the study sites with sugar and amino acid solutions and with leaf or floral bud EFN mimics, dominant EFN-feeding ants differentiated between solutions as well as between mimics. The castration parasite Crematogaster dohrni (northern study site) was the least selective and did not exhibit any clear feeding preferences, while the largely trophobiont-tending non-protective Myrmicaria brunnea (middle study site) preferred higher sucrose concentrations and certain essential/non-essential amino acid mixtures. The mutualistic Technomyrmex albipes (southern study site) preferred sucrose over glucose or fructose solutions and consumed the leaf EFN mimic to a greater extent than the floral bud EFN mimic. This young leaf EFN mimic had low sugar concentrations, the lowest viscosity and sugar:amino acid ratio, was rich in essential amino acids, and appeared ideally suited to the digestive physiology of T. albipes. This preference for young leaf EFN may explain the greater protection afforded to young leaves than to floral buds by T. albipes, and may also help to resolve ant-pollinator conflicts. The differential response of dominant ants to sugar, amino acids, or solution viscosity suggests that plants can fine-tune their interactions with local ants via EFN composition. Thus, EFN can mediate local partner-choice mechanisms in ant-plant interactions.

  9. A universal structured-design diagramer

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Program (FLOWCHARTER) generates standardized flowcharts and concordances for development and debugging of programs in any language. User describes programming-language grammar, providing syntax rules in Backus-Naur form (BNF), list of semantic rules, and set of concordance rules. Once grammar is described, user supplies only source code of program to be diagrammed. FLOWCHARTER automatically produces flow diagram and concordance. Source code for program is written for PASCAL Release 2 compiler, as distributed by University of Minnesota.

  10. Lattice and Phase Diagram in QCD

    SciTech Connect

    Lombardo, Maria Paola

    2008-10-13

    Model calculations have produced a number of very interesting expectations for the QCD Phase Diagram, and the task of a lattice calculations is to put these studies on a quantitative grounds. I will give an overview of the current status of the lattice analysis of the QCD phase diagram, from the quantitative results of mature calculations at zero and small baryochemical potential, to the exploratory studies of the colder, denser phase.

  11. Fluctuations and the QCD phase diagram

    SciTech Connect

    Schaefer, B.-J.

    2012-06-15

    In this contribution the role of quantum fluctuations for the QCD phase diagram is discussed. This concerns in particular the importance of the matter back-reaction to the gluonic sector. The impact of these fluctuations on the location of the confinement/deconfinement and the chiral transition lines as well as their interrelation are investigated. Consequences of our findings for the size of a possible quarkyonic phase and location of a critical endpoint in the phase diagram are drawn.

  12. ISS EPS Orbital Replacement Unit Block Diagrams

    NASA Technical Reports Server (NTRS)

    Schmitz, Gregory V.

    2001-01-01

    The attached documents are being provided to Switching Power Magazine for information purposes. This magazine is writing a feature article on the International Space Station Electrical Power System, focusing on the switching power processors. These units include the DC-DC Converter Unit (DDCU), the Bi-directional Charge/Discharge Unit (BCDU), and the Sequential Shunt Unit (SSU). These diagrams are high-level schematics/block diagrams depicting the overall functionality of each unit.

  13. The Sinorhizobium meliloti RNA chaperone Hfq influences central carbon metabolism and the symbiotic interaction with alfalfa

    PubMed Central

    2010-01-01

    Background The bacterial Hfq protein is able to interact with diverse RNA molecules, including regulatory small non-coding RNAs (sRNAs), and thus it is recognized as a global post-transcriptional regulator of gene expression. Loss of Hfq has an extensive impact in bacterial physiology which in several animal pathogens influences virulence. Sinorhizobium meliloti is a model soil bacterium known for its ability to establish a beneficial nitrogen-fixing intracellular symbiosis with alfalfa. Despite the predicted general involvement of Hfq in the establishment of successful bacteria-eukaryote interactions, its function in S. meliloti has remained unexplored. Results Two independent S. meliloti mutants, 2011-3.4 and 1021Δhfq, were obtained by disruption and deletion of the hfq gene in the wild-type strains 2011 and 1021, respectively, both exhibiting similar growth defects as free-living bacteria. Transcriptomic profiling of 1021Δhfq revealed a general down-regulation of genes of sugar transporters and some enzymes of the central carbon metabolism, whereas transcripts specifying the uptake and metabolism of nitrogen sources (mainly amino acids) were more abundant than in the wild-type strain. Proteomic analysis of the 2011-3.4 mutant independently confirmed these observations. Symbiotic tests showed that lack of Hfq led to a delayed nodulation, severely compromised bacterial competitiveness on alfalfa roots and impaired normal plant growth. Furthermore, a large proportion of nodules (55%-64%) elicited by the 1021Δhfq mutant were non-fixing, with scarce content in bacteroids and signs of premature senescence of endosymbiotic bacteria. RT-PCR experiments on RNA from bacteria grown under aerobic and microoxic conditions revealed that Hfq contributes to regulation of nifA and fixK1/K2, the genes controlling nitrogen fixation, although the Hfq-mediated regulation of fixK is only aerobiosis dependent. Finally, we found that some of the recently identified S. meliloti s

  14. Phase diagram of the Kane-Mele-Coulomb model

    NASA Astrophysics Data System (ADS)

    Hohenadler, M.; Parisen Toldin, F.; Herbut, I. F.; Assaad, F. F.

    2014-08-01

    We determine the phase diagram of the Kane-Mele model with a long-range Coulomb interaction using an exact quantum Monte Carlo method. Long-range interactions are expected to play a role in honeycomb materials because the vanishing density of states in the semimetallic weak-coupling phase suppresses screening. According to our results, the Kane-Mele-Coulomb model supports the same phases as the Kane-Mele-Hubbard model. The nonlocal part of the interaction promotes short-range sublattice charge fluctuations, which compete with antiferromagnetic order driven by the onsite repulsion. Consequently, the critical interaction for the magnetic transition is significantly larger than for the purely local Hubbard repulsion. Our numerical data are consistent with SU (2) Gross-Neveu universality for the semimetal to antiferromagnet transition, and with 3D XY universality for the quantum spin Hall to antiferromagnet transition.

  15. Influence of Constitution and Charge on Radical Pairing Interactions in Tris-radical Tricationic Complexes.

    PubMed

    Cheng, Chuyang; Cheng, Tao; Xiao, Hai; Krzyaniak, Matthew D; Wang, Yuping; McGonigal, Paul R; Frasconi, Marco; Barnes, Jonathan C; Fahrenbach, Albert C; Wasielewski, Michael R; Goddard, William A; Stoddart, J Fraser

    2016-07-01

    The results of a systematic investigation of trisradical tricationic complexes formed between cyclobis(paraquat-p-phenylene) bisradical dicationic (CBPQT(2(•+))) rings and a series of 18 dumbbells, containing centrally located 4,4'-bipyridinium radical cationic (BIPY(•+)) units within oligomethylene chains terminated for the most part by charged 3,5-dimethylpyridinium (PY(+)) and/or neutral 3,5-dimethylphenyl (PH) groups, are reported. The complexes were obtained by treating equimolar amounts of the CBPQT(4+) ring and the dumbbells containing BIPY(2+) units with zinc dust in acetonitrile solutions. Whereas UV-Vis-NIR spectra revealed absorption bands centered on ca. 1100 nm with quite different intensities for the 1:1 complexes depending on the constitutions and charges on the dumbbells, titration experiments showed that the association constants (Ka) for complex formation vary over a wide range, from 800 M(-1) for the weakest to 180 000 M(-1) for the strongest. While Coulombic repulsions emanating from PY(+) groups located at the ends of some of the dumbbells undoubtedly contribute to the destabilization of the trisradical tricationic complexes, solid-state superstructures support the contention that those dumbbells with neutral PH groups at the ends of flexible and appropriately constituted links to the BIPY(•+) units stand to gain some additional stabilization from C-H···π interactions between the CBPQT(2(•+)) rings and the PH termini on the dumbbells. The findings reported in this Article demonstrate how structural changes implemented remotely from the BIPY(•+) units influence their non-covalent bonding interactions with CBPQT(2(•+)) rings. Different secondary effects (Coulombic repulsions versus C-H···π interactions) are uncovered, and their contributions to both binding strengths associated with trisradical interactions and the kinetics of associations and dissociations are discussed at some length, supported by extensive DFT

  16. Methylation interactions in Arabidopsis hybrids require RNA-directed DNA methylation and are influenced by genetic variation.

    PubMed

    Zhang, Qingzhu; Wang, Dong; Lang, Zhaobo; He, Li; Yang, Lan; Zeng, Liang; Li, Yanqiang; Zhao, Cheng; Huang, Huan; Zhang, Heng; Zhang, Huiming; Zhu, Jian-Kang

    2016-07-19

    DNA methylation is a conserved epigenetic mark in plants and many animals. How parental alleles interact in progeny to influence the epigenome is poorly understood. We analyzed the DNA methylomes of Arabidopsis Col and C24 ecotypes, and their hybrid progeny. Hybrids displayed nonadditive DNA methylation levels, termed methylation interactions, throughout the genome. Approximately 2,500 methylation interactions occurred at regions where parental DNA methylation levels are similar, whereas almost 1,000 were at differentially methylated regions in parents. Methylation interactions were characterized by an abundance of 24-nt small interfering RNAs. Furthermore, dysfunction of the RNA-directed DNA methylation pathway abolished methylation interactions but did not affect the increased biomass observed in hybrid progeny. Methylation interactions correlated with altered genetic variation within the genome, suggesting that they may play a role in genome evolution. PMID:27382183

  17. Superconducting phase diagram of itinerant antiferromagnets

    NASA Astrophysics Data System (ADS)

    Rømer, A. T.; Eremin, I.; Hirschfeld, P. J.; Andersen, B. M.

    2016-05-01

    We study the phase diagram of the Hubbard model in the weak-coupling limit for coexisting spin-density-wave order and spin-fluctuation-mediated superconductivity. Both longitudinal and transverse spin fluctuations contribute significantly to the effective interaction potential, which creates Cooper pairs of the quasiparticles of the antiferromagnetic metallic state. We find a dominant dx2-y2-wave solution in both electron- and hole-doped cases. In the quasi-spin-triplet channel, the longitudinal fluctuations give rise to an effective attraction supporting a p -wave gap, but are overcome by repulsive contributions from the transverse fluctuations which disfavor p -wave pairing compared to dx2-y2. The subleading pair instability is found to be in the g -wave channel, but complex admixtures of d and g are not energetically favored since their nodal structures coincide. Inclusion of interband pairing, in which each fermion in the Cooper pair belongs to a different spin-density-wave band, is considered for a range of electron dopings in the regime of well-developed magnetic order. We demonstrate that these interband pairing gaps, which are nonzero in the magnetic state, must have the same parity under inversion as the normal intraband gaps. The self-consistent solution to the full system of five coupled gap equations gives intraband and interband pairing gaps of dx2-y2 structure and similar gap magnitude. In conclusion, the dx2-y2 gap dominates for both hole and electron doping inside the spin-density-wave phase.

  18. The influence of social norms upon behavioral expressions of implicit and explicit weight-related stigma in an interactive game.

    PubMed

    Pryor, John B; Reeder, Glenn D; Wesselmann, Eric D; Williams, Kipling D; Wirth, James H

    2013-06-01

    This research explored the roles of social influence and stigma-related attitudes in how people behaved toward an overweight female in an interactive computer game. Photographs were used to manipulate whether one of the players in the game was overweight or average weight. We found that both explicit and implicit anti-fat attitudes influenced interactions with an overweight player, but only when other players ostracized the overweight player, not when they included her. Under conditions of ostracism, explicit attitudes were better predictors of more controllable behaviors, while implicit attitudes were better predictors of more automatic behaviors.

  19. The Influence of Social Norms upon Behavioral Expressions of Implicit and Explicit Weight-Related Stigma in an Interactive Game

    PubMed Central

    Pryor, John B.; Reeder, Glenn D.; Wesselmann, Eric D.; Williams, Kipling D.; Wirth, James H.

    2013-01-01

    This research explored the roles of social influence and stigma-related attitudes in how people behaved toward an overweight female in an interactive computer game. Photographs were used to manipulate whether one of the players in the game was overweight or average weight. We found that both explicit and implicit anti-fat attitudes influenced interactions with an overweight player, but only when other players ostracized the overweight player, not when they included her. Under conditions of ostracism, explicit attitudes were better predictors of more controllable behaviors, while implicit attitudes were better predictors of more automatic behaviors. PMID:23766740

  20. Calculation of binary phase diagrams between the actinide elements, rare earth elements, and transition metal elements

    SciTech Connect

    Selle, J E

    1992-06-26

    Attempts were made to apply the Kaufman method of calculating binary phase diagrams to the calculation of binary phase diagrams between the rare earths, actinides, and the refractory transition metals. Difficulties were encountered in applying the method to the rare earths and actinides, and modifications were necessary to provide accurate representation of known diagrams. To calculate the interaction parameters for rare earth-rare earth diagrams, it was necessary to use the atomic volumes for each of the phases: liquid, body-centered cubic, hexagonal close-packed, and face-centered cubic. Determination of the atomic volumes of each of these phases for each element is discussed in detail. In some cases, empirical means were necessary. Results are presented on the calculation of rare earth-rare earth, rare earth-actinide, and actinide-actinide diagrams. For rare earth-refractory transition metal diagrams and actinide-refractory transition metal diagrams, empirical means were required to develop values for the enthalpy of vaporization for rare earth elements and values for the constant (C) required when intermediate phases are present. Results of using the values determined for each element are presented.

  1. The effective QCD phase diagram and the critical end point

    NASA Astrophysics Data System (ADS)

    Ayala, Alejandro; Bashir, Adnan; Cobos-Martínez, J. J.; Hernández-Ortiz, Saúl; Raya, Alfredo

    2015-08-01

    We study the QCD phase diagram on the temperature T and quark chemical potential μ plane, modeling the strong interactions with the linear sigma model coupled to quarks. The phase transition line is found from the effective potential at finite T and μ taking into account the plasma screening effects. We find the location of the critical end point (CEP) to be (μCEP /Tc, TCEP /Tc) ∼ (1.2, 0.8), where Tc is the (pseudo)critical temperature for the crossover phase transition at vanishing μ. This location lies within the region found by lattice inspired calculations. The results show that in the linear sigma model, the CEP's location in the phase diagram is expectedly determined solely through chiral symmetry breaking. The same is likely to be true for all other models which do not exhibit confinement, provided the proper treatment of the plasma infrared properties for the description of chiral symmetry restoration is implemented. Similarly, we also expect these corrections to be substantially relevant in the QCD phase diagram.

  2. Above–Belowground Herbivore Interactions in Mixed Plant Communities Are Influenced by Altered Precipitation Patterns

    PubMed Central

    Ryalls, James M. W.; Moore, Ben D.; Riegler, Markus; Johnson, Scott N.

    2016-01-01

    Root- and shoot-feeding herbivores have the capacity to influence one another by modifying the chemistry of the shared host plant. This can alter rates of nutrient mineralization and uptake by neighboring plants and influence plant–plant competition, particularly in mixtures combining grasses and legumes. Root herbivory-induced exudation of nitrogen (N) from legume roots, for example, may increase N acquisition by co-occurring grasses, with knock-on effects on grassland community composition. Little is known about how climate change may affect these interactions, but an important and timely question is how will grass–legume mixtures respond in a future with an increasing reliance on legume N mineralization in terrestrial ecosystems. Using a model grass–legume mixture, this study investigated how simultaneous attack on lucerne (Medicago sativa) by belowground weevils (Sitona discoideus) and aboveground aphids (Acyrthosiphon pisum) affected a neighboring grass (Phalaris aquatica) when subjected to drought, ambient, and elevated precipitation. Feeding on rhizobial nodules by weevil larvae enhanced soil water retention under ambient and elevated precipitation, but only when aphids were absent. While drought decreased nodulation and root N content in lucerne, grass root and shoot chemistry were unaffected by changes in precipitation. However, plant communities containing weevils but not aphids showed increased grass height and N concentrations, most likely associated with the transfer of N from weevil-attacked lucerne plants containing more nodules and higher root N concentrations compared with insect-free plants. Drought decreased aphid abundance by 54% but increased total and some specific amino acid concentrations (glycine, lysine, methionine, tyrosine, cysteine, histidine, arginine, aspartate, and glutamate), suggesting that aphid declines were being driven by other facets of drought (e.g., reduced phloem hydraulics). The presence of weevil larvae belowground

  3. Above-Belowground Herbivore Interactions in Mixed Plant Communities Are Influenced by Altered Precipitation Patterns.

    PubMed

    Ryalls, James M W; Moore, Ben D; Riegler, Markus; Johnson, Scott N

    2016-01-01

    Root- and shoot-feeding herbivores have the capacity to influence one another by modifying the chemistry of the shared host plant. This can alter rates of nutrient mineralization and uptake by neighboring plants and influence plant-plant competition, particularly in mixtures combining grasses and legumes. Root herbivory-induced exudation of nitrogen (N) from legume roots, for example, may increase N acquisition by co-occurring grasses, with knock-on effects on grassland community composition. Little is known about how climate change may affect these interactions, but an important and timely question is how will grass-legume mixtures respond in a future with an increasing reliance on legume N mineralization in terrestrial ecosystems. Using a model grass-legume mixture, this study investigated how simultaneous attack on lucerne (Medicago sativa) by belowground weevils (Sitona discoideus) and aboveground aphids (Acyrthosiphon pisum) affected a neighboring grass (Phalaris aquatica) when subjected to drought, ambient, and elevated precipitation. Feeding on rhizobial nodules by weevil larvae enhanced soil water retention under ambient and elevated precipitation, but only when aphids were absent. While drought decreased nodulation and root N content in lucerne, grass root and shoot chemistry were unaffected by changes in precipitation. However, plant communities containing weevils but not aphids showed increased grass height and N concentrations, most likely associated with the transfer of N from weevil-attacked lucerne plants containing more nodules and higher root N concentrations compared with insect-free plants. Drought decreased aphid abundance by 54% but increased total and some specific amino acid concentrations (glycine, lysine, methionine, tyrosine, cysteine, histidine, arginine, aspartate, and glutamate), suggesting that aphid declines were being driven by other facets of drought (e.g., reduced phloem hydraulics). The presence of weevil larvae belowground

  4. A study of the influence of forest gaps on fire-atmosphere interactions

    NASA Astrophysics Data System (ADS)

    Kiefer, Michael T.; Heilman, Warren E.; Zhong, Shiyuan; Charney, Joseph J.; Bian, Xindi

    2016-07-01

    Much uncertainty exists regarding the possible role that gaps in forest canopies play in modulating fire-atmosphere interactions in otherwise horizontally homogeneous forests. This study examines the influence of gaps in forest canopies on atmospheric perturbations induced by a low-intensity fire using the ARPS-CANOPY model, a version of the Advanced Regional Prediction System (ARPS) model with a canopy parameterization. A series of numerical experiments are conducted with a stationary low-intensity fire, represented in the model as a line of enhanced surface sensible heat flux. Experiments are conducted with and without forest gaps, and with gaps in different positions relative to the fire line. For each of the four cases considered, an additional simulation is performed without the fire to facilitate comparison of the fire-perturbed atmosphere and the background state. Analyses of both mean and instantaneous wind velocity, turbulent kinetic energy, air temperature, and turbulent mixing of heat are presented in order to examine the fire-perturbed atmosphere on multiple timescales. Results of the analyses indicate that the impact of the fire on the atmosphere is greatest in the case with the gap centered on the fire and weakest in the case with the gap upstream of the fire. It is shown that gaps in forest canopies have the potential to play a role in the vertical as well as horizontal transport of heat away from the fire. Results also suggest that, in order to understand how the fire will alter wind and turbulence in a heterogeneous forest, one needs to first understand how the forest heterogeneity itself influences the wind and turbulence fields without the fire.

  5. Host-synthesized secondary compounds influence the in vitro interactions between fungal endophytes of maize.

    PubMed

    Saunders, Megan; Kohn, Linda M

    2008-01-01

    Maize produces a suite of allelopathic secondary metabolites, the benzoxazinoids. 2,4-Dihydroxy-7-methoxy-2H-1,4-benzoxazin-3-one and 2,4-dihydroxy-2H-1,4-benzoxazin-3-one reside as glucosides in plant tissue and spontaneously degrade to 6-methoxy-2-benzoxazolinone (MBOA) and 2-benzoxazolinone (BOA) upon plant cell disruption. Several maize-associated fungi in the genus Fusarium can metabolize MBOA and BOA. BOA tolerance levels in 10 species of Fusarium and in the maize endophytes Nigrospora oryzae, Acremonium zeae, and Periconia macrospinosa were characterized. BOA tolerance ranged from 0.25 to 1.10 mg/ml among species. The influence of substrate alteration by one species on the subsequent growth of another species was assessed in the presence and absence of BOA. The colony area of the secondary colonizer in heterospecific interactions was compared to that in autospecific interactions (one isolate follows itself). In the presence of BOA, four of six secondary colonizers had greater growth (facilitation) when primary colonizers had higher BOA tolerance than the secondary colonizer. When the primary colonizer had lower tolerance than the secondary, three of six secondary colonizers were inhibited (competition) and three not significantly affected. In BOA-free medium, the number of isolates that were facilitated or inhibited was the same regardless of the tolerance level of the primary colonizer. Two of six secondary colonizers were facilitated, two inhibited, and two not significantly affected. This study provides some support for facilitation in stressful conditions under the Menge-Sutherland model. The results are not consistent with the corresponding prediction of competition in the absence of stress. The hypothesis drawn from these data is that in the presence of a toxin, fungal species that detoxify their substrate can enhance the colonization rate of less tolerant fungi.

  6. Host-Synthesized Secondary Compounds Influence the In Vitro Interactions between Fungal Endophytes of Maize▿

    PubMed Central

    Saunders, Megan; Kohn, Linda M.

    2008-01-01

    Maize produces a suite of allelopathic secondary metabolites, the benzoxazinoids. 2,4-Dihydroxy-7-methoxy-2H-1,4-benzoxazin-3-one and 2,4-dihydroxy-2H-1,4-benzoxazin-3-one reside as glucosides in plant tissue and spontaneously degrade to 6-methoxy-2-benzoxazolinone (MBOA) and 2-benzoxazolinone (BOA) upon plant cell disruption. Several maize-associated fungi in the genus Fusarium can metabolize MBOA and BOA. BOA tolerance levels in 10 species of Fusarium and in the maize endophytes Nigrospora oryzae, Acremonium zeae, and Periconia macrospinosa were characterized. BOA tolerance ranged from 0.25 to 1.10 mg/ml among species. The influence of substrate alteration by one species on the subsequent growth of another species was assessed in the presence and absence of BOA. The colony area of the secondary colonizer in heterospecific interactions was compared to that in autospecific interactions (one isolate follows itself). In the presence of BOA, four of six secondary colonizers had greater growth (facilitation) when primary colonizers had higher BOA tolerance than the secondary colonizer. When the primary colonizer had lower tolerance than the secondary, three of six secondary colonizers were inhibited (competition) and three not significantly affected. In BOA-free medium, the number of isolates that were facilitated or inhibited was the same regardless of the tolerance level of the primary colonizer. Two of six secondary colonizers were facilitated, two inhibited, and two not significantly affected. This study provides some support for facilitation in stressful conditions under the Menge-Sutherland model. The results are not consistent with the corresponding prediction of competition in the absence of stress. The hypothesis drawn from these data is that in the presence of a toxin, fungal species that detoxify their substrate can enhance the colonization rate of less tolerant fungi. PMID:17993551

  7. Influence of olive oil phenolic compounds on headspace aroma release by interaction with whey proteins.

    PubMed

    Genovese, Alessandro; Caporaso, Nicola; De Luca, Lucia; Paduano, Antonello; Sacchi, Raffaele

    2015-04-22

    The release of volatile compounds in an oil-in-water model system obtained from olive oil-whey protein (WP) pairing was investigated by considering the effect of phenolic compounds. Human saliva was used to simulate mouth conditions by retronasal aroma simulator (RAS) analysis. Twelve aroma compounds were quantified in the dynamic headspace by SPME-GC/MS. The results showed significant influences of saliva on the aroma release of virgin olive oil (VOO) volatiles also in the presence of WP. The interaction between WP and saliva leads to lower headspace release of ethyl esters and hexanal. Salivary components caused lower decrease of the release of acetates and alcohols. A lower release of volatile compounds was found in the RAS essay in comparison to that in orthonasal simulation of only refined olive oil (without addition of saliva or WP), with the exception of hexanal and 1-penten-3-one, where a significantly higher release was found. Our results suggest that the extent of retronasal odor (green, pungent) of these two volatile compounds is higher than orthonasal odor. An extra VOO was used to verify the release in model systems, indicating that WP affected aroma release more than model systems, while saliva seems to exert an opposite trend. A significant increase in aroma release was found when phenolic compounds were added to the system, probably due to the contrasting effects of binding of volatile compounds caused by WP, for the polyphenol-protein interaction phenomenon. Our study could be applied to the formulation of new functional foods to enhance flavor release and modulate the presence and concentrations of phenolics and whey proteins in food emulsions/dispersions. PMID:25832115

  8. Distinct parietal sites mediate the influences of mood, arousal, and their interaction on human recognition memory.

    PubMed

    Greene, Ciara M; Flannery, Oliver; Soto, David

    2014-12-01

    The two dimensions of emotion, mood valence and arousal, have independent effects on recognition memory. At present, however, it is not clear how those effects are reflected in the human brain. Previous research in this area has generally dealt with memory for emotionally valenced or arousing stimuli, but the manner in which interacting mood and arousal states modulate responses in memory substrates remains poorly understood. We investigated memory for emotionally neutral items while independently manipulating mood valence and arousal state by means of music exposure. Four emotional conditions were created: positive mood/high arousal, positive mood/low arousal, negative mood/high arousal, and negative mood/low arousal. We observed distinct effects of mood valence and arousal in parietal substrates of recognition memory. Positive mood increased activity in ventral posterior parietal cortex (PPC) and orbitofrontal cortex, whereas arousal condition modulated activity in dorsal PPC and the posterior cingulate. An interaction between valence and arousal was observed in left ventral PPC, notably in a parietal area distinct from the those identified for the main effects, with a stronger effect of mood on recognition memory responses here under conditions of relative high versus low arousal. We interpreted the PPC activations in terms of the attention-to-memory hypothesis: Increased arousal may lead to increased top-down control of memory, and hence dorsal PPC activation, whereas positive mood valence may result in increased activity in ventral PPC regions associated with bottom-up attention to memory. These findings indicate that distinct parietal sites mediate the influences of mood, arousal, and their interplay during recognition memory.

  9. Influence of external inputs and asymmetry of connections on information-geometric measures involving up to ten neuronal interactions.

    PubMed

    Nie, Yimin; Fellous, Jean-Marc; Tatsuno, Masami

    2014-10-01

    The investigation of neural interactions is crucial for understanding information processing in the brain. Recently an analysis method based on information geometry (IG) has gained increased attention, and the property of the pairwise IG measure has been studied extensively in relation to the two-neuron interaction. However, little is known about the property of IG measures involving more neuronal interactions. In this study, we systematically investigated the influence of external inputs and the asymmetry of connections on the IG measures in cases ranging from 1-neuron to 10-neuron interactions. First, the analytical relationship between the IG measures and external inputs was derived for a network of 10 neurons with uniform connections. Our results confirmed that the single and pairwise IG measures were good estimators of the mean background input and of the sum of the connection weights, respectively. For the IG measures involving 3 to 10 neuronal interactions, we found that the influence of external inputs was highly nonlinear. Second, by computer simulation, we extended our analytical results to asymmetric connections. For a network of 10 neurons, the simulation showed that the behavior of the IG measures in relation to external inputs was similar to the analytical solution obtained for a uniformly connected network. When the network size was increased to 1000 neurons, the influence of external inputs almost disappeared. This result suggests that all IG measures from 1-neuron to 10-neuron interactions are robust against the influence of external inputs. In addition, we investigated how the strength of asymmetry influenced the IG measures. Computer simulation of a 1000-neuron network showed that all the IG measures were robust against the modulation of the asymmetry of connections. Our results provide further support for an information-geometric approach and will provide useful insights when these IG measures are applied to real experimental spike data.

  10. Structure diagram of binary Lennard-Jones clusters

    NASA Astrophysics Data System (ADS)

    Mravlak, Marko; Kister, Thomas; Kraus, Tobias; Schilling, Tanja

    2016-07-01

    We analyze the structure diagram for binary clusters of Lennard-Jones particles by means of a global optimization approach for a large range of cluster sizes, compositions, and interaction energies and present a publicly accessible database of 180 000 minimal energy structures (http://softmattertheory.lu/clusters.html). We identify a variety of structures such as core-shell clusters, Janus clusters, and clusters in which the minority species is located at the vertices of icosahedra. Such clusters can be synthesized from nanoparticles in agglomeration experiments and used as building blocks in colloidal molecules or crystals. We discuss the factors that determine the formation of clusters with specific structures.

  11. Structure diagram of binary Lennard-Jones clusters.

    PubMed

    Mravlak, Marko; Kister, Thomas; Kraus, Tobias; Schilling, Tanja

    2016-07-14

    We analyze the structure diagram for binary clusters of Lennard-Jones particles by means of a global optimization approach for a large range of cluster sizes, compositions, and interaction energies and present a publicly accessible database of 180 000 minimal energy structures (http://softmattertheory.lu/clusters.html). We identify a variety of structures such as core-shell clusters, Janus clusters, and clusters in which the minority species is located at the vertices of icosahedra. Such clusters can be synthesized from nanoparticles in agglomeration experiments and used as building blocks in colloidal molecules or crystals. We discuss the factors that determine the formation of clusters with specific structures. PMID:27421400

  12. The Influence of MSI (Metal-Support Interactions) and the Solvent in Liquid-Phase Reactions

    SciTech Connect

    Vannice, M. A.

    2003-05-30

    Results were repeatedly obtained that were consistent with a hypothesis proposed at the beginning of this program, i.e., due to Metal-Support Interactions (MSI), unique active sites can be created in the metal-support interfacial region to enhance activity and improve selectivity in certain types of reactions, especially those involving the hydrogenation of carbonyl and unsaturated C=C bonds. Higher turnover frequencies (TOF-molecule/s/site) and increased selectivity for C=O bond versus C=C bond hydrogenation was established in the hydrogenation reactions of: acetone, crotonaldehyde, acetophenone, phenylethanol, acetylcyclohexane, benzaldehyde, benzyl alcohol, phenylacetaldehyde and citral over Pt/TiO{sub 2} MSI catalysts. Higher rates of hydrogenation benzene, toluene and xylene could be obtained over certain supported Pt and Pd catalysts. Au/TiO{sub 2} catalysts were developed that were active for CO hydrogenation at subambient temperatures. The influence of support and metal crystallite size were established for the adsorption of H{sub 2}, CO and O{sub 2} on families of Pt and Pd catalysts.

  13. Dopamine and cognitive control: sex-by-genotype interactions influence the capacity to switch attention.

    PubMed

    Gurvich, C; Rossell, S L

    2015-03-15

    Cognitive performance in healthy persons varies widely between individuals. Sex differences in cognition are well reported, and there is an emerging body of evidence suggesting that the relationship between dopaminergic neurotransmission, implicated in many cognitive functions, is modulated by sex. Here, we examine the influence of sex and genetic variations along the dopaminergic pathway on aspects of cognitive control. A total of 415 healthy individuals, selected from an international consortium linked to Brain Research and Integrative Neuroscience Network (BRAINnet), were genotyped for two common and functional genetic variations of dopamine regulating genes: the catechol-O-methyltransferase [COMT] gene (rs4680) and the dopamine receptor D2 [DRD2] gene (rs6277). Cognitive measures were selected to explore sustained attention (using a continuous performance task), switching of attention (using a Trails B adaptation) and working memory (a visual computerised adaptation of digit span). While there were no main effects for genotype across any tasks, analyses revealed significant sex by genotype interactions for the capacity to switch attention. In relation to COMT, superior performance was noted in females with the Val/Val genotype and for DRD2, superior performance was seen for TT females and CC males. These findings highlight the importance of considering genetic variation in baseline dopamine levels in addition to sex, when considering the impact of dopamine on cognition in healthy populations. These findings also have important implications for the many neuropsychiatric disorders that implicate dopamine, cognitive changes and sex differences.

  14. Quality of interactions influences everyday life in psychiatric inpatient care—patients’ perspectives

    PubMed Central

    Molin, Jenny; Graneheim, Ulla H.; Lindgren, Britt-Marie

    2016-01-01

    Everyday life consists of daily activities that are taken for granted. It forms the foundation for human efforts and contains elements of both comfort and boredom. Because everyday life escapes no one, life in a psychiatric ward will become ordinary while staying there. This study aims to explore everyday life in psychiatric inpatient care based on patients’ experiences. We individually interviewed 16 participants with experiences of psychiatric inpatient care and analysed the data in accordance with the methods of grounded theory. Data collection and analysis continued in parallel in accordance with the method. Our results showed that everyday life is linked to the core category quality of interactions influences everyday life, and three constructed categories—staff makes the difference, looking for shelter in a stigmatizing environment, and facing a confusing care content—were related to the core category. Our results highlight the importance of ordinary relationships between staff and patients in psychiatric inpatient care. These results can be used to develop nursing interventions to improve psychiatric inpatient care and might also be used as a basis for reflective dialogues among staff. PMID:26806313

  15. Influence of the composition of cement kiln dust on its interaction with fly ash and slag

    SciTech Connect

    Chaunsali, Piyush; Peethamparan, Sulapha

    2013-12-15

    Cement kiln dust (CKD), a by-product of the cement industry, contains significant amounts of alkali, free lime, chloride and sulfate. Wide variation reported in the chemical composition of CKDs limits their potential application as a sustainable binder component in concrete. In the current study, the performance of two different CKDs as components in a novel binder is evaluated. Several binders are developed by blending CKDs with fly ash or slag. Binders with 70% CKD were prepared at a water-to-binder ratio of 0.4, and heat-cured at 75 °C to accelerate the strength development. The hydration progress was monitored using X-ray diffraction, and morphological examination was performed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Ettringite and calcium aluminosilicate hydrate (C-A-S-H) were identified as the main hydration products in the hardened binder system. Strength development of CKD-based binder was found to be significantly influenced by its free lime and sulfate contents. -- Highlights: •Interaction of cement kiln dust with fly ash and slag was explored. •CKD with higher free lime and sulfate content increased the strength of binder. •C-S-H like reaction gel with fibrillar morphology is observed in CKD-based binders.

  16. Influence of gene interaction on complex trait variation with multilocus models.

    PubMed

    Mäki-Tanila, Asko; Hill, William G

    2014-09-01

    Although research effort is being expended into determining the importance of epistasis and epistatic variance for complex traits, there is considerable controversy about their importance. Here we undertake an analysis for quantitative traits utilizing a range of multilocus quantitative genetic models and gene frequency distributions, focusing on the potential magnitude of the epistatic variance. All the epistatic terms involving a particular locus appear in its average effect, with the number of two-locus interaction terms increasing in proportion to the square of the number of loci and that of third order as the cube and so on. Hence multilocus epistasis makes substantial contributions to the additive variance and does not, per se, lead to large increases in the nonadditive part of the genotypic variance. Even though this proportion can be high where epistasis is antagonistic to direct effects, it reduces with multiple loci. As the magnitude of the epistatic variance depends critically on the heterozygosity, for models where frequencies are widely dispersed, such as for selectively neutral mutations, contributions of epistatic variance are always small. Epistasis may be important in understanding the genetic architecture, for example, of function or human disease, but that does not imply that loci exhibiting it will contribute much genetic variance. Overall we conclude that theoretical predictions and experimental observations of low amounts of epistatic variance in outbred populations are concordant. It is not a likely source of missing heritability, for example, or major influence on predictions of rates of evolution.

  17. Influence of Acoustic Field Structure on Polarization Characteristics of Acousto-optic Interaction in Crystals

    NASA Astrophysics Data System (ADS)

    Muromets, A. V.; Trushin, A. S.

    Influence of acoustic field structure on polarization characteristics of acousto-optic interaction is investigated. It is shown that inhomogeneity of acoustic field and mechanism of ultrasound excitation causes changes in values of acousto-optic figure of merit for ordinary and extraordinary light beams in comparison with theoretic values. The theoretic values were derived under assumption that acoustic wave is homogeneous. Experimental analysis was carried out in acousto-optic cell based on lithium niobate crystal where the acoustic wave propagates at the angle 13 degrees to Z axis of the crystal. We used three different methods of ultrasound generation in the crystal: by means of external piezotransducer, by interdigital transducer and by two sets of electrodes placed on top of the crystal surface. In the latter case, the first pair of the electrodes was directed along X crystal axis, while the second pair of the electrodes was directed orthogonally to X crystal axis and the direction of ultrasound. Obtained values for diffraction efficiencies for ordinary and extraordinary polarized optical beams were qualitatively different which may be caused by spatial inhomogeneity of the generated acoustic waves in the crystal. Structure of acoustic field generated by these sets of electrodes was examined by laser probing. We performed the analysis of the acoustic field intensity using acousto-optic method. A relation of diffraction efficiencies for ordinary and extraordinary light waves was measured during each iteration of the laser probing.

  18. Dopamine and cognitive control: sex-by-genotype interactions influence the capacity to switch attention.

    PubMed

    Gurvich, C; Rossell, S L

    2015-03-15

    Cognitive performance in healthy persons varies widely between individuals. Sex differences in cognition are well reported, and there is an emerging body of evidence suggesting that the relationship between dopaminergic neurotransmission, implicated in many cognitive functions, is modulated by sex. Here, we examine the influence of sex and genetic variations along the dopaminergic pathway on aspects of cognitive control. A total of 415 healthy individuals, selected from an international consortium linked to Brain Research and Integrative Neuroscience Network (BRAINnet), were genotyped for two common and functional genetic variations of dopamine regulating genes: the catechol-O-methyltransferase [COMT] gene (rs4680) and the dopamine receptor D2 [DRD2] gene (rs6277). Cognitive measures were selected to explore sustained attention (using a continuous performance task), switching of attention (using a Trails B adaptation) and working memory (a visual computerised adaptation of digit span). While there were no main effects for genotype across any tasks, analyses revealed significant sex by genotype interactions for the capacity to switch attention. In relation to COMT, superior performance was noted in females with the Val/Val genotype and for DRD2, superior performance was seen for TT females and CC males. These findings highlight the importance of considering genetic variation in baseline dopamine levels in addition to sex, when considering the impact of dopamine on cognition in healthy populations. These findings also have important implications for the many neuropsychiatric disorders that implicate dopamine, cognitive changes and sex differences. PMID:25510197

  19. Influence of habitat manipulations on interactions between cutthroat trout and invertebrate drift. [Salmo clarki

    SciTech Connect

    Wilzbach, M.A.; Cummins, K.W.; Hall, J.D.

    1986-08-01

    The objectives of this study were to examine the interactions of the riparian setting (logged vs forested) and prey availability on the prey capture efficiency and growth of cutthroat trout, and to determine if the riparian setting influences the impact of trout predation on drift composition. Short-term relative growth rates of cutthroat trout, experimentally confined in stream pools, were greater in a logged than in a forested section of stream. Differences in growth rates were attributed to differences, among pools in invertebrate drift density, and to differences in trout foraging efficiency that were related to differences between the sections in the amount of overhead shading and substrate crevices. Mean percentages of introduced prey captured by trout were greater in logged control pools and pools of both sections whose bottoms were covered with fiberglass screening to eliminate substrate crevices than in forested control pools and logged pools that were artificially shaded. A logarithmic relationship was found between trout foraging efficiency and surface light of pools. Drift density significantly increased relative to controls in pools from which trout were removed in the logged reach, but not in the forested section. This may result from habitat features in the logged section that favor greater trout foraging success and the occurrence of behaviorally drifting prey taxa, which represent a predictable food supply for the trout.

  20. Clinical setting influences patterns of interaction between osteoporosis patient and physician.

    PubMed

    Gasparik, Andrea Ildiko

    2014-08-01

    The importance of healthy behavior for bone health, as well as low adherence to anti-osteoporosis medication are well-described problems. Both, lifestyle habits and compliance with drug-therapy are influenced by the relationship between patients and physicians. We analyzed 152 consecutive doctor-patient interactions conducted in public and private practices specialized in the management of osteoporosis. We recorded the duration of the consultation and the relative length of: (a) Personal and medical history collection, (b) Physical examination, (c) Explanation of the diagnosis and treatment modalities, and (d) Administrative tasks. The overall length and the respective duration of the four phases of the consultation significantly differ in private versus public practices. In the private practice, doctors spend more time with the patient and dedicate a higher proportion of their time to history collection and explanation of diagnosis/treatment for osteoporosis. While we do not integrate data on medication adherence, we believe that since more time is dedicated to health education, patients consulting in the private sector have a greater probability to adopt a healthy lifestyle and better/ longer take anti-osteoporosis medications. Further investigations are needed to assess if the differences in patient and doctor behaviors in the public-private settings have a significant impact on therapeutic adherence and subsequently fracture reduction in patients receiving anti-osteoporosis treatment.

  1. Dietary fat type and energy restriction interactively influence plasma leptin concentration in rats.

    PubMed

    Cha, M C; Jones, P J

    1998-08-01

    To investigate whether dietary fat source and energy restriction interactively influence plasma leptin levels and its association of leptin with insulin action, rats were fed diets containing either fish, safflower oil, or beef tallow (20% wt/wt) for 10 weeks. Groups of rats consumed each diet ad libitum or at 85% or 70% of ad libitum energy intake in a design that held fat intake constant. Graded levels of energy restriction caused body weight to decrease (P < 0.001) differently according to the dietary fat provided. Plasma leptin concentrations were 60% higher (P < 0.05) in the groups fed fish oil and safflower oil ad libitum compared with those in the beef tallow group, despite smaller perirenal fat mass and fat cell size in the fish oil-fed animals. Energy restriction resulted in a 62% decrease (P < 0.05) in leptin levels in fish oil- and safflower oil-fed rats, whereas no changes were observed in beef tallow-fed animals. Plasma insulin levels were lower (P < 0.05) in the fish oil group fed ad libitum compared with those in the two other diet groups. These data demonstrate a hyperleptinemic effect in animals consuming diets rich in polyunsaturated fatty acid, which can be normalized to the level of saturated fat consumption by mild energy restriction. Thus, dietary fatty acid composition, independent of adipose tissue mass, is an important determinant of circulating leptin level in diet-induced obesity.

  2. Predicting the influence of long-range molecular interactions on macroscopic-scale diffusion by homogenization of the Smoluchowski equation.

    PubMed

    Kekenes-Huskey, P M; Gillette, A K; McCammon, J A

    2014-05-01

    The macroscopic diffusion constant for a charged diffuser is in part dependent on (1) the volume excluded by solute "obstacles" and (2) long-range interactions between those obstacles and the diffuser. Increasing excluded volume reduces transport of the diffuser, while long-range interactions can either increase or decrease diffusivity, depending on the nature of the potential. We previously demonstrated [P. M. Kekenes-Huskey et al., Biophys. J. 105, 2130 (2013)] using homogenization theory that the configuration of molecular-scale obstacles can both hinder diffusion and induce diffusional anisotropy for small ions. As the density of molecular obstacles increases, van der Waals (vdW) and electrostatic interactions between obstacle and a diffuser become significant and can strongly influence the latter's diffusivity, which was neglected in our original model. Here, we extend this methodology to include a fixed (time-independent) potential of mean force, through homogenization of the Smoluchowski equation. We consider the diffusion of ions in crowded, hydrophilic environments at physiological ionic strengths and find that electrostatic and vdW interactions can enhance or depress effective diffusion rates for attractive or repulsive forces, respectively. Additionally, we show that the observed diffusion rate may be reduced independent of non-specific electrostatic and vdW interactions by treating obstacles that exhibit specific binding interactions as "buffers" that absorb free diffusers. Finally, we demonstrate that effective diffusion rates are sensitive to distribution of surface charge on a globular protein, Troponin C, suggesting that the use of molecular structures with atomistic-scale resolution can account for electrostatic influences on substrate transport. This approach offers new insight into the influence of molecular-scale, long-range interactions on transport of charged species, particularly for diffusion-influenced signaling events occurring in crowded

  3. Predicting the influence of long-range molecular interactions on macroscopic-scale diffusion by homogenization of the Smoluchowski equation

    SciTech Connect

    Kekenes-Huskey, P. M.; Gillette, A. K.; McCammon, J. A.

    2014-05-07

    The macroscopic diffusion constant for a charged diffuser is in part dependent on (1) the volume excluded by solute “obstacles” and (2) long-range interactions between those obstacles and the diffuser. Increasing excluded volume reduces transport of the diffuser, while long-range interactions can either increase or decrease diffusivity, depending on the nature of the potential. We previously demonstrated [P. M. Kekenes-Huskey et al., Biophys. J. 105, 2130 (2013)] using homogenization theory that the configuration of molecular-scale obstacles can both hinder diffusion and induce diffusional anisotropy for small ions. As the density of molecular obstacles increases, van der Waals (vdW) and electrostatic interactions between obstacle and a diffuser become significant and can strongly influence the latter's diffusivity, which was neglected in our original model. Here, we extend this methodology to include a fixed (time-independent) potential of mean force, through homogenization of the Smoluchowski equation. We consider the diffusion of ions in crowded, hydrophilic environments at physiological ionic strengths and find that electrostatic and vdW interactions can enhance or depress effective diffusion rates for attractive or repulsive forces, respectively. Additionally, we show that the observed diffusion rate may be reduced independent of non-specific electrostatic and vdW interactions by treating obstacles that exhibit specific binding interactions as “buffers” that absorb free diffusers. Finally, we demonstrate that effective diffusion rates are sensitive to distribution of surface charge on a globular protein, Troponin C, suggesting that the use of molecular structures with atomistic-scale resolution can account for electrostatic influences on substrate transport. This approach offers new insight into the influence of molecular-scale, long-range interactions on transport of charged species, particularly for diffusion-influenced signaling events occurring in

  4. The Semiotic Structure of Geometry Diagrams: How Textbook Diagrams Convey Meaning

    ERIC Educational Resources Information Center

    Dimmel, Justin K.; Herbst, Patricio G.

    2015-01-01

    Geometry diagrams use the visual features of specific drawn objects to convey meaning about generic mathematical entities. We examine the semiotic structure of these visual features in two parts. One, we conduct a semiotic inquiry to conceptualize geometry diagrams as mathematical texts that comprise choices from different semiotic systems. Two,…

  5. Teacher-Student Interaction, Empathy and Their Influence on Learning in Swimming Lessons

    ERIC Educational Resources Information Center

    Lémonie, Yannick; Light, Richard; Sarremejane, Philippe

    2016-01-01

    The bulk of interest in the role that interaction plays in learning in sport and physical education (PE) has focused on peer interaction at the expense of teacher-student interaction. This article redresses this imbalance in the literature by reporting on a study that inquired into the nature of teacher-student interaction and its effect on…

  6. 49 CFR 1152.10 - System diagram map.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... of its rail system or file only a narrative description of its lines that provides all of the... date upon which the diagram or narrative, or any amended diagram or narrative, is filed with the Board... pending before the Board on the date upon which the diagram or narrative, or any amended diagram...

  7. 49 CFR 1152.10 - System diagram map.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... of its rail system or file only a narrative description of its lines that provides all of the... date upon which the diagram or narrative, or any amended diagram or narrative, is filed with the Board... pending before the Board on the date upon which the diagram or narrative, or any amended diagram...

  8. 49 CFR 1152.10 - System diagram map.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... of its rail system or file only a narrative description of its lines that provides all of the... date upon which the diagram or narrative, or any amended diagram or narrative, is filed with the Board... pending before the Board on the date upon which the diagram or narrative, or any amended diagram...

  9. The Use of Computational Diagrams and Nomograms in Higher Education.

    ERIC Educational Resources Information Center

    Brandenburg, Richard K.; Simpson, William A.

    1984-01-01

    The use of computational diagrams and nomographs for the calculations that frequently occur in college administration is examined. Steps in constructing a nomograph and a four-dimensional computational diagram are detailed, and uses of three- and four-dimensional diagrams are covered. Diagrams and nomographs are useful in the following cases: (1)…

  10. 49 CFR 1152.10 - System diagram map.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... of its rail system or file only a narrative description of its lines that provides all of the... date upon which the diagram or narrative, or any amended diagram or narrative, is filed with the Board... pending before the Board on the date upon which the diagram or narrative, or any amended diagram...

  11. 49 CFR 1152.10 - System diagram map.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... of its rail system or file only a narrative description of its lines that provides all of the... date upon which the diagram or narrative, or any amended diagram or narrative, is filed with the Board... pending before the Board on the date upon which the diagram or narrative, or any amended diagram...

  12. Fishbone Diagrams: Organize Reading Content with a "Bare Bones" Strategy

    ERIC Educational Resources Information Center

    Clary, Renee; Wandersee, James

    2010-01-01

    Fishbone diagrams, also known as Ishikawa diagrams or cause-and-effect diagrams, are one of the many problem-solving tools created by Dr. Kaoru Ishikawa, a University of Tokyo professor. Part of the brilliance of Ishikawa's idea resides in the simplicity and practicality of the diagram's basic model--a fish's skeleton. This article describes how…

  13. The Interaction of Principal and Teacher Instructional Influence as a Measure of Leadership as an Organizational Quality

    ERIC Educational Resources Information Center

    Jackson, Karen M.; Marriott, Christine

    2012-01-01

    Purpose: This article presents the design and test of a measure of school leadership as an organizational quality through the interaction of principal and teacher instructional influence. The Organizational Leadership Model hypothesizes four distinct conditions of school leadership, and the analysis investigates the relationship between teacher,…

  14. The Influence of Dating Anxiety on Normative Experiences of Dating, Sexual Interactions, and Alcohol Consumption among Canadian Middle Adolescents

    ERIC Educational Resources Information Center

    Boyle, Andrea M.; O'Sullivan, Lucia F.

    2013-01-01

    Adolescents tend to consume alcohol and find romantic and sexual partners in mixed-group settings that are unmonitored by adults. Relatively little is known about the influence that dating anxiety may have with these social interactions. A sample of 163 high school students (aged 14-17 years) completed online surveys assessing dating, sex, and…

  15. Glucokinase regulatory proten genetic variant interacts with omega-3 PUFA to influence insulin resistance and inflammation in metabolic syndrome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glucokinase Regulatory Protein (GCKR) plays a central role regulating both hepatic triglyceride and glucose metabolism. Fatty acids are key metabolic regulators, which interact with genetic factors and influence glucose metabolism and other metabolic traits. Omega-3 polyunsaturated fatty acids (n-3...

  16. Distances between Disciplines: Influences of Interdisciplinary Discourse on Faculty Scholarship and Interaction at One University. ASHE Annual Meeting Paper.

    ERIC Educational Resources Information Center

    Frost, Susan H.; Jean, Paul M.

    This qualitative case study explores the influences of sustained discourse across disciplines on college faculty attitudes and behaviors related to scholarship and intellectual interaction. The study, conducted at Emory University (Georgia), involved 25 faculty who had participated in a series of semester-long seminars that explored topics of…

  17. Untangling Teacher-Child Play Interactions: Do Teacher Education and Experience Influence "Good-Fit" Responses to Children's Play?

    ERIC Educational Resources Information Center

    Trawick-Smith, Jeffrey; Dziurgot, Tracy

    2010-01-01

    The purpose of this study was to determine if levels of teacher education and experience would influence how teachers respond to children's play needs in a preschool classroom. The interactions of eight teachers--three of whom were categorized as high education/high experience, three as low education/high experience, and two as low education/low…

  18. Early Adverse Environments and Genetic Influences on Age at First Sex: Evidence for Gene × Environment Interaction

    ERIC Educational Resources Information Center

    Carlson, Marie D.; Mendle, Jane; Harden, K. Paige

    2014-01-01

    Youth who experience adverse environments in early life initiate sexual activity at a younger age, on average, than those from more advantaged circumstances. Evolutionary theorists have posited that ecological stress precipitates earlier reproductive and sexual onset, but it is unclear how stressful environments interact with genetic influences on…

  19. The Butterfly diagram leopard skin pattern

    NASA Astrophysics Data System (ADS)

    Ternullo, Maurizio

    2011-08-01

    A time-latitude diagram where spotgroups are given proportional relevance to their area is presented. The diagram reveals that the spotted area distribution is higly dishomogeneous, most of it being concentrated in few, small portions (``knots'') of the Butterfly Diagram; because of this structure, the BD may be properly described as a cluster of knots. The description, assuming that spots scatter around the ``spot mean latitude'' steadily drifting equatorward, is challenged. Indeed, spots cluster around at as many latitudes as knots; a knot may appear at either lower or higher latitudes than previous ones, in a seemingly random way; accordingly, the spot mean latitude abruptly drifts equatorward or even poleward at any knot activation, in spite of any smoothing procedure. Preliminary analyses suggest that the activity splits, in any hemisphere, into two or more distinct ``activity waves'', drifting equatorward at a rate higher than the spot zone as a whole.

  20. When do procedural fairness and outcome fairness interact to influence employees' work attitudes and behaviors? The moderating effect of uncertainty.

    PubMed

    De Cremer, David; Brockner, Joel; Fishman, Ariel; van Dijke, Marius; van Olffen, Woody; Mayer, David M

    2010-03-01

    Prior research has shown that procedural fairness interacts with outcome fairness to influence employees' work attitudes (e.g., organizational commitment) and behaviors (e.g., job performance, organizational citizenship behavior), such that employees' tendencies to respond more positively to higher procedural fairness are stronger when outcome fairness is relatively low. In the present studies, we posited that people's uncertainty about their standing as organizational members would have a moderating influence on this interactive relationship between procedural fairness and outcome fairness, in that the interactive relationship was expected to be more pronounced when uncertainty was high. Using different operationalizations of uncertainty of standing (i.e., length of tenure as a proxy, along with self-reports and coworkers' reports), we found support for this hypothesis in 4 field studies spanning 3 different countries.

  1. B-Fe-U Phase Diagram

    NASA Astrophysics Data System (ADS)

    Dias, Marta; Carvalho, Patrícia Almeida; Mardolcar, Umesh Vinaica; Tougait, Olivier; Noël, Henri; Gonçalves, António Pereira

    2014-04-01

    The liquidus projection of the U-rich corner of the B-Fe-U phase diagram is proposed based on X-ray powder diffraction measurements, differential thermal analysis, and scanning electron microscopy observations complemented with energy- and wavelength-dispersive X-ray spectroscopies. Two ternary reactions in this U-rich region were observed and their approximate temperatures were established. In addition, an overview of the complete phase diagram is given, including the liquidus projection; isothermal sections at 1053 K, 1223 K, and 1373 K (780 °C, 950 °C, and 1100 °C); and a U:(Fe,B) = 1:5 isopleth.

  2. On Cooperative Behavior in Distributed Teams: The Influence of Organizational Design, Media Richness, Social Interaction, and Interaction Adaptation.

    PubMed

    Håkonsson, Dorthe D; Obel, Børge; Eskildsen, Jacob K; Burton, Richard M

    2016-01-01

    Self-interest vs. cooperation is a fundamental dilemma in animal behavior as well as in human and organizational behavior. In organizations, how to get people to cooperate despite or in conjunction with their self-interest is fundamental to the achievement of a common goal. While both organizational designs and social interactions have been found to further cooperation in organizations, some of the literature has received contradictory support, just as very little research, if any, has examined their joint effects in distributed organizations, where communication is usually achieved via different communication media. This paper reviews the extant literature and offers a set of hypotheses to integrate current theories and explanations. Further, it discusses how future research should examine the joint effects of media, incentives, and social interactions.

  3. On Cooperative Behavior in Distributed Teams: The Influence of Organizational Design, Media Richness, Social Interaction, and Interaction Adaptation.

    PubMed

    Håkonsson, Dorthe D; Obel, Børge; Eskildsen, Jacob K; Burton, Richard M

    2016-01-01

    Self-interest vs. cooperation is a fundamental dilemma in animal behavior as well as in human and organizational behavior. In organizations, how to get people to cooperate despite or in conjunction with their self-interest is fundamental to the achievement of a common goal. While both organizational designs and social interactions have been found to further cooperation in organizations, some of the literature has received contradictory support, just as very little research, if any, has examined their joint effects in distributed organizations, where communication is usually achieved via different communication media. This paper reviews the extant literature and offers a set of hypotheses to integrate current theories and explanations. Further, it discusses how future research should examine the joint effects of media, incentives, and social interactions. PMID:27242605

  4. On Cooperative Behavior in Distributed Teams: The Influence of Organizational Design, Media Richness, Social Interaction, and Interaction Adaptation

    PubMed Central

    Håkonsson, Dorthe D.; Obel, Børge; Eskildsen, Jacob K.; Burton, Richard M.

    2016-01-01

    Self-interest vs. cooperation is a fundamental dilemma in animal behavior as well as in human and organizational behavior. In organizations, how to get people to cooperate despite or in conjunction with their self-interest is fundamental to the achievement of a common goal. While both organizational designs and social interactions have been found to further cooperation in organizations, some of the literature has received contradictory support, just as very little research, if any, has examined their joint effects in distributed organizations, where communication is usually achieved via different communication media. This paper reviews the extant literature and offers a set of hypotheses to integrate current theories and explanations. Further, it discusses how future research should examine the joint effects of media, incentives, and social interactions. PMID:27242605

  5. Influence of humic substances on plant-microbes interactions in the rhizosphere

    NASA Astrophysics Data System (ADS)

    Puglisi, Edoardo; Pascazio, Silvia; Spaccini, Riccardo; Crecchio, Carmine; Trevisan, Marco; Piccolo, Alessandro

    2013-04-01

    Humic substances are known to play a wide range of effects on the physiology of plant and microbes. This is of particular relevance in the rhizosphere of terrestrial environments, where the reciprocal interactions between plants roots, soil constituents and microorganisms strongly influence the plants acquisition of nutrients. Chemical advances are constantly improving our knowledge on humic substances: their supra-molecular architecture, as well as the moltitude of their chemical constituents, many of which are biologically active. An approach for linking the structure of humic substances with their biological activity in the rhizosphere is the use of rhizoboxes, which allow applying a treatment (e.g., an amendment with humic substances) in an upper soil-plant compartment and take measurements in a lower isolated rhizosphere compartment that can be sampled at desired distances from the rhizoplane. This approach can be adopted to assess the effects of several humic substances, as well as composted materials, on maize plants rhizodeposition of carbon, and in turn on the structure and activity of rhizosphere microbial communities. In order to gain a complete understanding of processes occurring in the complex soil-plant-microorganisms tripartite system, rhizobox experiments can be coupled with bacterial biosensors for the detection and quantification of bioavailable nutrients, chemical analyses of main rhizodeposits constituents, advanced chemical characterizations of humic substances, DNA-fingerprinting of microbial communities, and multivariate statistical approaches to manage the dataset produced and to infer general conclusions. By such an approach it was found that humic substances are significantly affecting the amount of carbon deposited by plant roots. This induction effect is more evident for substances with more hydrophobic and complex structure, thus supporting the scientific hypothesis of the "microbial loop model", which assumes that plants feed

  6. Spatial ecology of predator-prey interactions: corridors and patch shape influence seed predation.

    SciTech Connect

    J. L . Orrock; B. J. Danielson; M. J. Burns; D. J. Levey

    2003-02-03

    J.L. Orrock, B.J. Danielson, M.J. Burns, and D.J. Levey. 2003. Spatial ecology of predator-prey interactions: corridors and patch shape influence seed predation. Ecology, 84(10):2589-2599. Abstract: Corridors that connect patches of disjunct habitat may be promising tools for mediating the negative impacts of habitat fragmentation, but little is known about how corridors affect ecological interactions. In eight 12-ha experimental landscapes, we examined how corridors affect the impact of invertebrate, rodent, and avian seed predators on pokeweed, Phytolacca americana. Over 13 months in 2000 and 2001, we quantified the effects of patch shape, connectivity, and predator type on the number of seeds germinating in the field (germinants), seed removal, and the viability of remaining seeds. Corridors did not affect the number of P. americana germinants in experimental exclosures or the viability of seeds remaining in exclosures. However, corridors affected the removal of seeds in a predator-specific manner: invertebrates removed more seeds in unconnected patches, whereas rodents removed more seeds in connected patches. Seed removal by birds was similar in connected and unconnected patches. Total seed removal by all seed predators was not affected by corridors, because invertebrates removed more seeds where rodents removed fewer seeds, and vice versa. Overall, seed predation signi®cantly reduced the number and viability of remaining seeds, and reduced the number of germinants in 2000 but not in 2001. The abundance of naturally occurring P. americana plants in our experimental patches in 2000 decreased with increasing seed removal from exclosures but was not related to viability or germinants in 2000, suggesting that seed removal may shape the distribution and abundance of this species. Complementary patterns of seed removal by rodents and invertebrates suggest that corridors alter the effects of these predator taxa by changing the relative amounts of edge and core

  7. The effects of using diagramming as a representational technique on high school students' achievement in solving math word problems

    NASA Astrophysics Data System (ADS)

    Banerjee, Banmali

    Methods and procedures for successfully solving math word problems have been, and continue to be a mystery to many U.S. high school students. Previous studies suggest that the contextual and mathematical understanding of a word problem, along with the development of schemas and their related external representations, positively contribute to students' accomplishments when solving word problems. Some studies have examined the effects of diagramming on students' abilities to solve word problems that only involved basic arithmetic operations. Other studies have investigated how instructional models that used technology influenced students' problem solving achievements. Still other studies have used schema-based instruction involving students with learning disabilities. No study has evaluated regular high school students' achievements in solving standard math word problems using a diagramming technique without technological aid. This study evaluated students' achievement in solving math word problems using a diagramming technique. Using a quasi-experimental experimental pretest-posttest research design, quantitative data were collected from 172 grade 11 Hispanic English language learners (ELLS) and African American learners whose first language is English (EFLLs) in 18 classes at an inner city high school in Northern New Jersey. There were 88 control and 84 experimental students. The pretest and posttest of each participating student and samples of the experimental students' class assignments provided the qualitative data for the study. The data from this study exhibited that the diagramming method of solving math word problems significantly improved student achievement in the experimental group (p<.01) compared to the control group. The study demonstrated that urban, high school, ELLs benefited from instruction that placed emphasis on the mathematical vocabulary and symbols used in word problems and that both ELLs and EFLLs improved their problem solving success

  8. Influence of Dzyaloshinshkii-Moriya interaction on quantum correlations in two-qubit Werner states and MEMS

    NASA Astrophysics Data System (ADS)

    Sharma, Kapil K.; Pandey, S. N.

    2015-04-01

    In this paper, we study the influence of Dzyaloshinskii-Moriya (DM) interaction on quantum correlations in two-qubit Werner states and maximally entangled mixed states (MEMS). We consider our system as a closed system of a qubit pair and one auxiliary qubit, which interact with any one of the qubit of the pair through DM interaction. We show that DM interaction, taken along any direction ( x or y or z), does not affect two-qubit Werner states. On the other hand, the MEMS are affected by x and z components of DM interaction and remain unaffected by the y component. Further, we find that the state (i.e., probability amplitude) of auxiliary qubit does not affect the quantum correlations in both the states, and only DM interaction strength influences the quantum correlations. So one can avoid the intention to prepare the specific state of auxiliary qubit to manipulate the quantum correlations in both the states. We mention here that avoiding the preparation of state can contribute to cost reduction in quantum information processing. We also observe the phenomenon of entanglement sudden death in the present study.

  9. The Influence of Host Plant Extrafloral Nectaries on Multitrophic Interactions: An Experimental Investigation.

    PubMed

    Koptur, Suzanne; Jones, Ian M; Peña, Jorge E

    2015-01-01

    A field experiment was conducted with outplantings of the native perennial shrub Senna mexicana var. chapmanii in a semi-natural area adjacent to native pine rockland habitat in southern Florida. The presence of ants and the availability of extrafloral nectar were manipulated in a stratified random design. Insect communities were monitored and recorded over a period of six months with a view to addressing three main questions. Do ants provide biotic defense against key herbivores on S. chapmanii? Is the presence of ants on S. chapmanii mediated by EFN? Finally, are there ecological costs associated with the presence of ants on S. chapmanii, such as a reduction in alternative predator or parasitoid numbers? Herbivores on S. chapmanii included immature stages of three pierid butterflies, and adult weevils. Eight species of ants were associated with the plants, and other predators included spiders, ladybugs, wasps, and hemipterans. Parasitic, haemolymph-sucking midges (Ceratopogonidae) and parasitoid flies were also associated with the caterpillar herbivores, and possibly the extrafloral nectaries of the plants. The presence of ants did not appear to influence oviposition by butterflies, as numbers of lepidopterans of all developmental stages did not differ among treatments. Significantly more late instar caterpillars, however, were observed on plants with ants excluded, indicating that ants remove small caterpillars from plants. Substantially more alternative predators (spiders, ladybugs, and wasps) were observed on plants with ants excluded. Rates of parasitization did not differ among the treatments, but there were substantially fewer caterpillars succumbing to virus among those collected from control plants. We provide a rare look at facultative ant-plant mutualisms in the context of the many other interactions with which they overlap. We conclude that ants provide some biotic defense against herbivores on S. chapmanii, and plants benefit overall from the presence

  10. The Influence of Host Plant Extrafloral Nectaries on Multitrophic Interactions: An Experimental Investigation

    PubMed Central

    Koptur, Suzanne; Jones, Ian M.; Peña, Jorge E.

    2015-01-01

    A field experiment was conducted with outplantings of the native perennial shrub Senna mexicana var. chapmanii in a semi-natural area adjacent to native pine rockland habitat in southern Florida. The presence of ants and the availability of extrafloral nectar were manipulated in a stratified random design. Insect communities were monitored and recorded over a period of six months with a view to addressing three main questions. Do ants provide biotic defense against key herbivores on S. chapmanii? Is the presence of ants on S. chapmanii mediated by EFN? Finally, are there ecological costs associated with the presence of ants on S. chapmanii, such as a reduction in alternative predator or parasitoid numbers? Herbivores on S. chapmanii included immature stages of three pierid butterflies, and adult weevils. Eight species of ants were associated with the plants, and other predators included spiders, ladybugs, wasps, and hemipterans. Parasitic, haemolymph-sucking midges (Ceratopogonidae) and parasitoid flies were also associated with the caterpillar herbivores, and possibly the extrafloral nectaries of the plants. The presence of ants did not appear to influence oviposition by butterflies, as numbers of lepidopterans of all developmental stages did not differ among treatments. Significantly more late instar caterpillars, however, were observed on plants with ants excluded, indicating that ants remove small caterpillars from plants. Substantially more alternative predators (spiders, ladybugs, and wasps) were observed on plants with ants excluded. Rates of parasitization did not differ among the treatments, but there were substantially fewer caterpillars succumbing to virus among those collected from control plants. We provide a rare look at facultative ant-plant mutualisms in the context of the many other interactions with which they overlap. We conclude that ants provide some biotic defense against herbivores on S. chapmanii, and plants benefit overall from the presence

  11. Temperature-mediated biotic interactions influence enemy release of nonnative species in warming environments.

    PubMed

    Fey, Samuel B; Herren, Cristina M

    2014-08-01

    "Enemy release" occurs when invading species suffer from interactions with pathogens, parasites, herbivores, or predators to a lesser degree than native species due to a lack of shared evolutionary history. Here we provide strong support for the hypothesis that variable thermal sensitivities between a consumer and its resources can generate temperature-dependent enemy release using both a mathematical model and a field experiment. We identify three common scenarios where changes in temperature should alter enemy release based on asymmetric responses among enemies and their resources to changes in temperature: (1) the vital rates of a shared enemy are more sensitive to changes in temperature than its resources, (2) the enemy's thermal maximum for consumption is higher than the resources' maxima for growth, and (3) the invading resource has a higher thermal maximum for growth than its native competitor. Mathematical representations indicated that warming is capable of altering enemy release in each of these three scenarios. We also tested our hypothesis using a mesocosm warming experiment in a system that exhibits variable thermal sensitivities between a predator and its native and nonnative prey. We conducted a six-week experiment manipulating the presence of Lepomis sunfish (present, absent) and water temperature (ambient, heated) using the nonnative crustacean zooplankter, Daphnia lumholtzi, whose morphological defenses reduce predation from juvenile sunfish relative to native Daphnia pulex. Our results indicate that D. lumholtzi benefited to a greater extent from the presence of Lepomis predators as temperatures increase. Taken together, our model and experiment indicate that changes in environmental temperature may directly influence the success of nonnative species and may assist with forecasting the community consequences of biological invasions in a warming world. PMID:25230475

  12. Influence of Cu(II) on the interaction between sulfite and horseradish peroxidase in vitro

    NASA Astrophysics Data System (ADS)

    Lan, Jie; Guo, Dong-Sheng; Yuan, Xiao-Ying

    2007-06-01

    This paper discussed the quantitative influence of Cu(II) on the interaction between horseradish peroxidase (HRP) and sulfite (SO 32-), which is a derivate of sulfite dioxide in human bodies, by using fluorescence spectrum and ultraviolet (UV) absorption spectrometry in vitro. The results show that under the conditions of physiological pH and room-temperature, Cu(II) can bind strongly with both the protein part and the ferroporphyrin part in HRP at a low concentration (10 -4 mol L -1), and the combination constants are 2.047 × 10 3 and 7.66 × 10 2 L mol -1, respectively. Under the same conditions, SO 32- at low concentrations (<0.15 mol L -1) has little quenching for the fluorescence of HRP at 330 nm, and the combination constant is 0.108 L mol -1. While the fluorescence intensity at 440 nm enhance gradually with the increased concentration of SO 32- (<0.1 mol L -1), and the combination constant is 8.219 L mol -1. These indicate that SO 32- at low concentration has little reaction with the enzyme protein part in HRP but obvious reaction with the ferroporphyrin part in HRP. After SO 32- at low concentrations is added into the HRP-Cu(II) binary system, the reaction constants between SO 32- and the enzyme protein part in HRP increase rapidly. Compared with the absence of Cu(II), the combination constant of SO 32- with the enzyme protein part in HRP increases nearly 70 times with a certain Cu(II) concentration (5.0 × 10 -4 mol L -1) in the system. However, the presence of Cu(II) in the system has little effect on the reaction constants between SO 32- and the ferroporphyrin part in HRP.

  13. Influence of nuclear interactions in polyethylene range compensators for carbon-ion radiotherapy

    SciTech Connect

    Kanematsu, Nobuyuki Koba, Yusuke; Ogata, Risa; Himukai, Takeshi

    2014-07-15

    Purpose: A recent study revealed that polyethylene (PE) would cause extra carbon-ion attenuation per range shift by 0.45%/cm due to compositional differences in nuclear interactions. The present study aims to assess the influence of PE range compensators on tumor dose in carbon-ion radiotherapy. Methods: Carbon-ion radiation was modeled to be composed of primary carbon ions and secondary particles, for each of which the dose and the relative biological effectiveness (RBE) were estimated at a tumor depth in the middle of spread-out Bragg peak. Assuming exponential behavior for attenuation and yield of these components with depth, the PE effect on dose was calculated for clinical carbon-ion beams and was partly tested by experiment. The two-component model was integrated into a treatment-planning system and the PE effect was estimated in two clinical cases. Results: The attenuation per range shift by PE was 0.1%–0.3%/cm in dose and 0.2%–0.4%/cm in RBE-weighted dose, depending on energy and range-modulation width. This translates into reduction of RBE-weighted dose by up to 3% in extreme cases. In the treatment-planning study, however, the effect on RBE-weighted dose to tumor was typically within 1% reduction. Conclusions: The extra attenuation of primary carbon ions in PE was partly compensated by increased secondary particles for tumor dose. In practical situations, the PE range compensators would normally cause only marginal errors as compared to intrinsic uncertainties in treatment planning, patient setup, beam delivery, and clinical response.

  14. Family and School Socioeconomic Disadvantage: Interactive Influences on Adolescent Dating Violence Victimization

    PubMed Central

    Spriggs, Aubrey L.; Halpern, Carolyn Tucker; Herring, Amy H; Schoenbach, Victor J

    2010-01-01

    Although low socioeconomic status has been positively associated with adult partner violence, its relationship to adolescent dating violence remains unclear. Further, few studies have examined the relationship between contextual disadvantage and adolescent dating violence, or the interactive influences of family and contextual disadvantage. Guided by Social Disorganization Theory, Relative Deprivation Theory, and Gendered Resource Theory, we analyzed data from the U.S. National Longitudinal Study of Adolescent Health (1994-1996) to explore how family and school disadvantage relate to dating violence victimization. Psychological and minor physical victimization were self-reported by adolescents in up to six heterosexual romantic or sexual relationships. Family and school disadvantage were based on a principal component analysis of soecioeconomic indicators reported by adolescents and parents. In weighted multilevel random effects models, between-school variability in dating violence victimization was proportionately small but substantive: 10% for male victimization and 5% for female victimization. In bivariate analyses, family disadvantage was positively related to victimization for both males and females; however, school disadvantage was only related to males’ physical victimization. In models adjusted for race/ethnicity, relative age within the school, and mean school age, neither family nor school disadvantage remained related to males’ victimization. For females, family disadvantage remained significantly positively associated with victimization, but was modified by school disadvantage: family disadvantage was more strongly associated with dating violence victimization in more advantaged schools. Findings support gendered resource theory, and suggest that status differentials between females and their school context may increase their vulnerability to dating violence victimization. PMID:19375207

  15. Mycorrhizal Influences On Soil Biogeochemistry In Forests: Are There Biosphere Consequences Of Rhizosphere Interactions?

    NASA Astrophysics Data System (ADS)

    Phillips, R.; Rosling, A.

    2011-12-01

    Temperate forests have experienced dramatic changes in forest composition over the last several decades owing land use change, insect outbreaks, nitrogen deposition and climate change. Understanding the consequences of such changes for carbon (C) and nutrient retention is vital to accurately predict terrestrial feedbacks to global climate change. We sought to test the hypothesis that tree species that form associations with arbuscular mycorrhizal (AM) fungi influence soil biogeochemistry in ways that are fundamentally different from tree species that form associations with ectomycorrhizal (ECM) fungi. We examined tree-mycorrhizal interactions in the central hardwood forests of southern Indiana where a rich assemblage of AM (e.g. maples, ashes, tulip poplar, black cherry) and ECM (e.g. oaks, hickories, beech, pine) tree species co-occur on soils developed from similar parent materials. Across 35 plots along a "mycorrhizal gradient" (plots varying in the relative abundance of AM vs. ECM trees), we found striking differences in soil pH, carbon, (C), nitrogen (N) and phosphorus (P) cycling in upper surface soils. Soil pH varied by three pH units across the gradient, and was positively correlated with the relative abundance of tree species within each mycorrhizal type (r2 = 0.65; p < 0.0001). Similarly, indices of C, N, and P availability were strongly correlated with the abundance of trees within a mycorrhizal association (r2 = 0.73, p < 0.0001; r2 = 0.55, p < 0.0001; r2 = 0.16, p = 0.019; respectively). Collectively, our results suggest that AM- and ECM-dominated stands may differ in their effects on chemical weathering and denudation, with important consequences for C and nutrient retention, and feedbacks to global change.

  16. Influence of soil moisture-carbon cycle interactions on the terrestrial carbon cycle over Europe

    NASA Astrophysics Data System (ADS)

    Mystakidis, Stefanos; Davin, Edouard L.; Gruber, Nicolas; Seneviratne, Sonia I.

    2016-04-01

    Water availability is a crucial limiting factor for terrestrial ecosystems, but relatively few studies have quantitatively assessed the influence of soil moisture variability on the terrestrial carbon cycle. Here, we investigate the role of soil moisture variability and state in the contemporary terrestrial carbon cycle over Europe. For this we use a Regional Earth System Model (RESM) based on the COSMO-CLM Regional Climate Model, coupled to the Community Land Model version 4.0 (CLM4.0) and its carbon-nitrogen module. The simulation setup consists of a control simulation over the period 1979-2010 in which soil moisture is interactive and three sensitivity simulations in which soil moisture is prescribed to a mean, a very dry or a very wet seasonal cycle without inter-annual variability. The cumulative net biome productivity varies markedly between the different experiments ranging from a strong sink of up to 6PgC in the wet experiment to a source of up to 1.2PgC in the dry experiment. Changes in the land carbon uptake are driven by a combination of two factors: the direct impact of soil moisture on plant's carbon uptake (essentially in southern Europe) and an indirect effect through changes in temperature affecting ecosystem respiration (mainly in central and northern Europe). We find that removing temporal variations in soil moisture dampens interannual variations in terrestrial carbon fluxes (Gross Primary Productivity, respiration, Net Biome Productivity) by more than 50% over most of Europe. Moreover, the analysis reveals that on annual scale about two-thirds of central Europe and about 70% of southern Europe display statistically significant effect of drying and/or wetting on the terrestrial carbon budget and its components. Our findings confirm the crucial role of soil moisture in determining the magnitude and the inter-annual variability in land CO2 uptake which is a key contributor to the year-to-year variations in atmospheric CO2 concentration.

  17. Effect of speed matching on fundamental diagram of pedestrian flow

    NASA Astrophysics Data System (ADS)

    Fu, Zhijian; Luo, Lin; Yang, Yue; Zhuang, Yifan; Zhang, Peitong; Yang, Lizhong; Yang, Hongtai; Ma, Jian; Zhu, Kongjin; Li, Yanlai

    2016-09-01

    Properties of pedestrian may change along their moving path, for example, as a result of fatigue or injury, which has never been properly investigated in the past research. The paper attempts to study the speed matching effect (a pedestrian adjusts his velocity constantly to the average velocity of his neighbors) and its influence on the density-velocity relationship (a pedestrian adjust his velocity to the surrounding density), known as the fundamental diagram of the pedestrian flow. By the means of the cellular automaton, the simulation results fit well with the empirical data, indicating the great advance of the discrete model for pedestrian dynamics. The results suggest that the system velocity and flow rate increase obviously under a big noise, i.e., a diverse composition of pedestrian crowd, especially in the region of middle or high density. Because of the temporary effect, the speed matching has little influence on the fundamental diagram. Along the entire density, the relationship between the step length and the average pedestrian velocity is a piecewise function combined two linear functions. The number of conflicts reaches the maximum with the pedestrian density of 2.5 m-2, while decreases by 5.1% with the speed matching.

  18. Global phase diagram of a doped Kitaev-Heisenberg model

    SciTech Connect

    Okamoto, Satoshi

    2013-01-01

    The global phase diagram of a doped Kitaev-Heisenberg model is studied using an $SU(2)$ slave-boson mean-field method. Near the Kitaev limit, $p$-wave superconducting states which break the time-reversal symmetry are stabilized as reported by You {\\it et al.} [Phys. Rev. B {\\bf 86}, 085145 (2012)] irrespective of the sign of the Kitaev interaction. By further doping, a $d$-wave superconducting state appears when the Kitaev interaction is antiferromagnetic, while another $p$-wave superconducting state appears when the Kitaev interaction is ferromagnetic. This $p$-wave superconducting state does not break the time-reversal symmetry as reported by Hyart {\\it et al.} [Phys. Rev. B {\\bf 85}, 140510 (2012)], and such a superconducting state also appears when the antiferromagnetic Kitaev interaction and the ferromagnetic Heisenberg interaction compete. This work, thus, demonstrates the clear difference between the antiferromagnetic Kitaev model and the ferromagnetic Kitaev model when carriers are doped while these models are equivalent in the undoped limit, and how novel superconducting states emerge when the Kitaev interaction and the Heisenberg interaction compete.

  19. Study flow diagrams in Cochrane systematic review updates: an adapted PRISMA flow diagram.

    PubMed

    Stovold, Elizabeth; Beecher, Deirdre; Foxlee, Ruth; Noel-Storr, Anna

    2014-05-29

    Cochrane systematic reviews are conducted and reported according to rigorous standards. A study flow diagram must be included in a new review, and there is clear guidance from the PRISMA statement on how to do this. However, for a review update, there is currently no guidance on how study flow diagrams should be presented. To address this, a working group was formed to find a solution and produce guidance on how to use these diagrams in review updates.A number of different options were devised for how these flow diagrams could be used in review updates, and also in cases where multiple searches for a review or review update have been conducted. These options were circulated to the Cochrane information specialist community for consultation and feedback. Following the consultation period, the working group refined the guidance and made the recommendation that for review updates an adapted PRISMA flow diagram should be used, which includes an additional box with the number of previously included studies feeding into the total. Where multiple searches have been conducted, the results should be added together and treated as one set of results.There is no existing guidance for using study flow diagrams in review updates. Our adapted diagram is a simple and pragmatic solution for showing the flow of studies in review updates.

  20. Nonverbal Poetry: Family Life-Space Diagrams.

    ERIC Educational Resources Information Center

    Bardill, Donald R.

    2001-01-01

    Examines life-space diagrams as a form of nonverbal poetry which taps personal feelings, tells a story, and characterizes a particular life situation, forming a useful therapy technique that provides a family the opportunity to examine its internal family relationships. Offers two case studies, discusses five levels of knowing and awareness, and…

  1. Computer-Generated Diagrams for the Classroom.

    ERIC Educational Resources Information Center

    Carle, Mark A.; Greenslade, Thomas B., Jr.

    1986-01-01

    Describes 10 computer programs used to draw diagrams usually drawn on chalkboards, such as addition of three vectors, vector components, range of a projectile, lissajous figures, beats, isotherms, Snell's law, waves passing through a lens, magnetic field due to Helmholtz coils, and three curves. Several programming tips are included. (JN)

  2. Journeys on the H-R diagram

    SciTech Connect

    Kaler, J.B.

    1988-05-01

    The evolution of various types of stars along the H-R diagram is discussed. Star birth and youth is addressed, and the events that occur due to core contraction, shell burning, and double-shell burning are described. The evolutionary courses of planetary nebulae, white dwarfs, and supernovas are examined.

  3. Complexities of One-Component Phase Diagrams

    ERIC Educational Resources Information Center

    Ciccioli, Andrea; Glasser, Leslie

    2011-01-01

    For most materials, the solid at and near the triple-point temperature is denser than the liquid with which it is in equilibrium. However, for water and certain other materials, the densities of the phases are reversed, with the solid being less dense. The profound consequences for the appearance of the "pVT" diagram of one-component materials…

  4. Constructing Causal Diagrams to Learn Deliberation

    ERIC Educational Resources Information Center

    Easterday, Matthew W.; Aleven, Vincent; Scheines, Richard; Carver, Sharon M.

    2009-01-01

    Policy problems like "What should we do about global warming?" are ill-defined in large part because we do not agree on a system to represent them the way we agree Algebra problems should be represented by equations. As a first step toward building a policy deliberation tutor, we investigated: (a) whether causal diagrams help students learn to…

  5. Fog Machines, Vapors, and Phase Diagrams

    ERIC Educational Resources Information Center

    Vitz, Ed

    2008-01-01

    A series of demonstrations is described that elucidate the operation of commercial fog machines by using common laboratory equipment and supplies. The formation of fogs, or "mixing clouds", is discussed in terms of the phase diagram for water and other chemical principles. The demonstrations can be adapted for presentation suitable for elementary…

  6. Image Attributes: A Study of Scientific Diagrams.

    ERIC Educational Resources Information Center

    Brunskill, Jeff; Jorgensen, Corinne

    2002-01-01

    Discusses advancements in imaging technology and increased user access to digital images, as well as efforts to develop adequate indexing and retrieval methods for image databases. Describes preliminary results of a study of undergraduates that explored the attributes naive subjects use to describe scientific diagrams. (Author/LRW)

  7. Dynamic Tactile Diagram Simplification on Refreshable Displays

    ERIC Educational Resources Information Center

    Rastogi, Ravi; Pawluk, Dianne T. V.

    2013-01-01

    The increasing use of visual diagrams in educational and work environments, and even our daily lives, has created obstacles for individuals who are blind or visually impaired to "independently" access the information they represent. Although physical tactile pictures can be created to convey the visual information, it is typically a slow,…

  8. Phase diagram of spiking neural networks

    PubMed Central

    Seyed-allaei, Hamed

    2015-01-01

    In computer simulations of spiking neural networks, often it is assumed that every two neurons of the network are connected by a probability of 2%, 20% of neurons are inhibitory and 80% are excitatory. These common values are based on experiments, observations, and trials and errors, but here, I take a different perspective, inspired by evolution, I systematically simulate many networks, each with a different set of parameters, and then I try to figure out what makes the common values desirable. I stimulate networks with pulses and then measure their: dynamic range, dominant frequency of population activities, total duration of activities, maximum rate of population and the occurrence time of maximum rate. The results are organized in phase diagram. This phase diagram gives an insight into the space of parameters – excitatory to inhibitory ratio, sparseness of connections and synaptic weights. This phase diagram can be used to decide the parameters of a model. The phase diagrams show that networks which are configured according to the common values, have a good dynamic range in response to an impulse and their dynamic range is robust in respect to synaptic weights, and for some synaptic weights they oscillates in α or β frequencies, independent of external stimuli. PMID:25788885

  9. NFHS Court and Field Diagram Guide.

    ERIC Educational Resources Information Center

    Gillis, John, Ed.

    This guide contains a comprehensive collection of diagrams and specifications of playing fields and courts used in interscholastic and recreational sports, along with information on how to set up various formats of tournament drawings, how to compute golf handicaps, and how to convert metric-to-English distances. Lists are provided of national…

  10. Weight diagram construction of Lax operators

    SciTech Connect

    Carbon, S.L.; Piard, E.J.

    1991-10-01

    We review and expand methods introduced in our previous paper. It is proved that cyclic weight diagrams corresponding to representations of affine Lie algebras allow one to construct the associated Lax operator. The resultant Lax operator is in the Miura-like form and generates the modified KdV equations. The algorithm is extended to the super-symmetric case.

  11. The Binary Temperature-Composition Phase Diagram

    ERIC Educational Resources Information Center

    Sanders, Philip C.; Reeves, James H.; Messina, Michael

    2006-01-01

    The equations for the liquid and gas lines in the binary temperature-composition phase diagram are derived by approximating that delta(H)[subscript vap] of the two liquids are equal. It is shown that within this approximation, the resulting equations are not too difficult to present in an undergraduate physical chemistry lecture.

  12. Indirect genetic effects influence antipredator behavior in guppies: estimates of the coefficient of interaction psi and the inheritance of reciprocity.

    PubMed

    Bleakley, Bronwyn H; Brodie, Edmund D

    2009-07-01

    How and why cooperation evolves, particularly among nonrelatives, remains a major paradox for evolutionary biologists and behavioral ecologists. Although much attention has focused on fitness consequences associated with cooperating, relatively little is known about the second component of evolutionary change, the inheritance of cooperation or reciprocity. The genetics of behaviors that can only be expressed in the context of interactions are particularly difficult to describe because the relevant genes reside in multiple social partners. Indirect genetic effects (IGEs) describe the influence of genes carried in social partners on the phenotype of a focal individual and thus provide a novel approach to quantifying the genetics underlying interactions such as reciprocal cooperation. We used inbred lines of guppies and a novel application of IGE theory to describe the dual genetic control of predator inspection and social behavior, both classic models of reciprocity. We identified effects of focal strain, social group strain, and interactions between focal and group strains on variation in focal behavior. We measured psi, the coefficient of the interaction, which describes the degree to which an individual's phenotype is influenced by the phenotype of its social partners. The genetic identity of social partners substantially influences inspection behavior, measures of threat assessment, and schooling and does so in positively reinforcing manner. We therefore demonstrate strong IGEs for antipredator behavior that represent the genetic variation necessary for the evolution of reciprocity.

  13. Influence and interactions of multi-factors on the bioavailability of PAHs in compost amended contaminated soils.

    PubMed

    Wu, Guozhong; Li, Xingang; Kechavarzi, Cédric; Sakrabani, Ruben; Sui, Hong; Coulon, Frédéric

    2014-07-01

    Compost amendment to contaminated soils is a potential approach for waste recycling and soil remediation. The relative importance and interactions of multiple factors on PAH bioavailability in soils were investigated using conjoint analysis and five-way analysis of variance. Results indicated that soil type and contact time were the two most significant factors influencing the PAH bioavailability in amended soils. The other two factors (compost type and ratio of compost addition) were less important but their interactions with other factors were significant. Specifically the 4-factor interactions showed that compost addition stimulated the degradation of high molecular PAHs at the initial stage (3 month) by enhancing the competitive sorption within PAH groups. Such findings suggest that a realistic decision-making towards hydrocarbon bioavailability assessment should consider interactions among various factors. Further to this, this study demonstrated that compost amendment can enhance the removal of recalcitrant hydrocarbons such as PAHs in contaminated soils.

  14. Influence of N-terminal hydrophobicity of cationic peptides on thermodynamics of their interaction with plasmid DNA.

    PubMed

    Goparaju, Geetha N; Bruist, Michael F; Chandran, C Satish; Gupta, Pardeep K

    2009-05-01

    There is a need to understand the thermodynamics of interaction of cationic peptides with DNA to design better peptide based non-viral gene delivery vectors. The main aim of this study was to understand the influence of N-terminal hydrophobicity of cationic amphiphilic peptides on thermodynamics of interaction with plasmid DNA. The model peptides used were TATPTD and TATPTDs modified at the N-terminal with hydrophobic amino acids. The thermodynamic binding data from isothermal titration calorimetry were compared with ethidium bromide analysis and ultrafiltration to correlate the binding parameters with the structural features of the various peptides used. It was observed that peptides having a smaller hydrophobic domain at the N-terminal have good DNA condensing ability compared with the ones with a longer hydrophobic domain. Calorimetry of peptides that reached saturation binding indicated that enthalpy and entropy are favorable for the interaction. Moreover, the interaction of these peptides with DNA appears to be predominantly electrostatic.

  15. Influence and interactions of multi-factors on the bioavailability of PAHs in compost amended contaminated soils.

    PubMed

    Wu, Guozhong; Li, Xingang; Kechavarzi, Cédric; Sakrabani, Ruben; Sui, Hong; Coulon, Frédéric

    2014-07-01

    Compost amendment to contaminated soils is a potential approach for waste recycling and soil remediation. The relative importance and interactions of multiple factors on PAH bioavailability in soils were investigated using conjoint analysis and five-way analysis of variance. Results indicated that soil type and contact time were the two most significant factors influencing the PAH bioavailability in amended soils. The other two factors (compost type and ratio of compost addition) were less important but their interactions with other factors were significant. Specifically the 4-factor interactions showed that compost addition stimulated the degradation of high molecular PAHs at the initial stage (3 month) by enhancing the competitive sorption within PAH groups. Such findings suggest that a realistic decision-making towards hydrocarbon bioavailability assessment should consider interactions among various factors. Further to this, this study demonstrated that compost amendment can enhance the removal of recalcitrant hydrocarbons such as PAHs in contaminated soils. PMID:24875869

  16. Influence of perylenediimide–pyrene supramolecular interactions on the stability of DNA-based hybrids: Importance of electrostatic complementarity

    PubMed Central

    Winiger, Christian B; Langenegger, Simon M; Khorev, Oleg

    2014-01-01

    Summary Aromatic π–π stacking interactions are ubiquitous in nature, medicinal chemistry and materials sciences. They play a crucial role in the stacking of nucleobases, thus stabilising the DNA double helix. The following paper describes a series of chimeric DNA–polycyclic aromatic hydrocarbon (PAH) hybrids. The PAH building blocks are electron-rich pyrene and electron-poor perylenediimide (PDI), and were incorporated into complementary DNA strands. The hybrids contain different numbers of pyrene–PDI interactions that were found to directly influence duplex stability. As the pyrene–PDI ratio approaches 1:1, the stability of the duplexes increases with an average value of 7.5 °C per pyrene–PDI supramolecular interaction indicating the importance of electrostatic complementarity for aromatic π–π stacking interactions. PMID:25161715

  17. Students' different understandings of class diagrams

    NASA Astrophysics Data System (ADS)

    Boustedt, Jonas

    2012-03-01

    The software industry needs well-trained software designers and one important aspect of software design is the ability to model software designs visually and understand what visual models represent. However, previous research indicates that software design is a difficult task to many students. This article reports empirical findings from a phenomenographic investigation on how students understand class diagrams, Unified Modeling Language (UML) symbols, and relations to object-oriented (OO) concepts. The informants were 20 Computer Science students from four different universities in Sweden. The results show qualitatively different ways to understand and describe UML class diagrams and the "diamond symbols" representing aggregation and composition. The purpose of class diagrams was understood in a varied way, from describing it as a documentation to a more advanced view related to communication. The descriptions of class diagrams varied from seeing them as a specification of classes to a more advanced view, where they were described to show hierarchic structures of classes and relations. The diamond symbols were seen as "relations" and a more advanced way was seeing the white and the black diamonds as different symbols for aggregation and composition. As a consequence of the results, it is recommended that UML should be adopted in courses. It is briefly indicated how the phenomenographic results in combination with variation theory can be used by teachers to enhance students' possibilities to reach advanced understanding of phenomena related to UML class diagrams. Moreover, it is recommended that teachers should put more effort in assessing skills in proper usage of the basic symbols and models and students should be provided with opportunities to practise collaborative design, e.g. using whiteboards.

  18. Graphical Synthesis of Colloid Transport Results on Quirk-Schofield Diagrams

    NASA Astrophysics Data System (ADS)

    Mays, D. C.

    2008-05-01

    The degree of colloid dispersion, or conversely the degree of flocculation, is crucial for understanding colloid transport in natural porous media, since it determines whether colloids are mobile or immobile. Additionally, in porous media containing more than a few percent fines, the degree of colloid dispersion also influences the permeability, and consequently the practicality of fluid extraction or injection. Colloid dispersion is largely determined by the aqueous chemistry, specifically pH, ionic strength, and sodium adsorption ratio (SAR). In the soil science literature, the effects of these three variables on colloid dispersion are commonly illustrated on Quirk-Schofield diagrams. In contrast, Quirk-Schofield diagrams appear to have been overlooked in the contaminant hydrology literature. This presentation will demonstrate the usefulness of Quirk-Schofield diagrams for presenting and interpreting a diversity of published colloid transport results, ranging from microbial pathogens to engineered nanoparticles to colloid-facilitated transport of metals. In particular, a quantitative analysis of published findings is presented using new Quirk-Schofield diagrams for kaolinite, illite, and montmorillonite, three clay minerals that are common in natural porous media. Additionally, because there is a relationship between colloid dispersion and permeability, this presentation will also show how Quirk-Schofield diagrams can provide insight into permeability changes, with applications to aquifer hydraulics and reservoir damage. The common aspects of all these results will be apparent, demonstrating that Quirk-Schofield diagrams are a simple, graphical technique that can be used to synthesize findings across the diverse applications where colloids play a central role. This study also suggests a framework for consistent reporting of colloid transport results: (1) measure the effects of pH, ionic strength, and SAR on colloid dispersion; (2) report results on Quirk

  19. Effects of aspect ratio on the phase diagram of spheroidal particles

    NASA Astrophysics Data System (ADS)

    Kutlu, Songul; Haaga, Jason; Rickman, Jeffrey; Gunton, James

    Ellipsoidal particles occur in both colloidal and protein science. Models of protein phase transitions based on interacting spheroidal particles can often be more realistic than those based on spherical molecules. One of the interesting questions is how the aspect ratio of spheroidal particles affects the phase diagram. Some results have been obtained in an earlier study by Odriozola (J. Chem. Phys. 136:134505 (2012)). In this poster we present results for the phase diagram of hard spheroids interacting via a quasi-square-well potential, for different aspect ratios. These results are obtained from Monte Carlo simulations using the replica exchange method. We find that the phase diagram, including the crystal phase transition, is sensitive to the choice of aspect ratio. G. Harold and Leila Y. Mathers Foundation.

  20. Using cellular network diagrams to interpret large-scale datasets: past progress and future challenges

    NASA Astrophysics Data System (ADS)

    Karp, Peter D.; Latendresse, Mario; Paley, Suzanne

    2011-03-01

    Cellular networks are graphs of molecular interactions within the cell. Thanks to the confluence of genome sequencing and bioinformatics, scientists are now able to reconstruct cellular network models for more than 1,000 organisms. A variety of bioinformatics tools have been developed to support the visualization and navigation of cellular network data. Another important application is the use of cellular network diagrams to visualize and interpret large-scale datasets, such as gene-expression data. We present the Cellular Overview, a network visualization tool developed at SRI International (SRI) to support visualization, navigation, and interpretation of large-scale datasets on metabolic networks. Different variations of the diagram have been generated algorithmically for more than 1,000 organisms. We discuss the graphical design of the diagram and its interactive capabilities.

  1. Ethanol Concentration Influences the Mechanisms of Wine Tannin Interactions with Poly(L-proline) in Model Wine.

    PubMed

    McRae, Jacqui M; Ziora, Zyta M; Kassara, Stella; Cooper, Matthew A; Smith, Paul A

    2015-05-01

    Changes in ethanol concentration influence red wine astringency, and yet the effect of ethanol on wine tannin-salivary protein interactions is not well understood. Isothermal titration calorimetry (ITC) was used to measure the binding strength between the model salivary protein, poly(L-proline) (PLP) and a range of wine tannins (tannin fractions from a 3- and a 7-year old Cabernet Sauvignon wine) across different ethanol concentrations (5, 10, 15, and 40% v/v). Tannin-PLP interactions were stronger at 5% ethanol than at 40% ethanol. The mechanism of interaction changed for most tannin samples across the wine-like ethanol range (10-15%) from a combination of hydrophobic and hydrogen binding at 10% ethanol to only hydrogen binding at 15% ethanol. These results indicate that ethanol concentration can influence the mechanisms of wine tannin-protein interactions and that the previously reported decrease in wine astringency with increasing alcohol may, in part, relate to a decrease tannin-protein interaction strength.

  2. Phase diagram and storage capacity of sequence processing neural networks

    NASA Astrophysics Data System (ADS)

    Düring, A.; Coolen, A. C. C.; Sherrington, D.

    1998-10-01

    We solve the dynamics of Hopfield-type neural networks which store sequences of patterns, close to saturation. The asymmetry of the interaction matrix in such models leads to violation of detailed balance, ruling out an equilibrium statistical mechanical analysis. Using generating functional methods we derive exact closed equations for dynamical order parameters, namely the sequence overlap and correlation and response functions, in the thermodynamic limit. We calculate the time translation invariant solutions of these equations, describing stationary limit cycles, which leads to a phase diagram. The effective retarded self-interaction usually appearing in symmetric models is here found to vanish, which causes a significantly enlarged storage capacity of 0305-4470/31/43/005/img6, compared with 0305-4470/31/43/005/img7 for Hopfield networks storing static patterns. Our results are tested against extensive computer simulations and excellent agreement is found.

  3. Maternal rank influences the outcome of aggressive interactions between immature chimpanzees

    PubMed Central

    Markham, A. Catherine; Lonsdorf, Elizabeth V.; Pusey, Anne E.; Murray, Carson M.

    2015-01-01

    For many long-lived mammalian species, extended maternal investment has a profound effect on offspring integration in complex social environments. One component of this investment may be aiding young in aggressive interactions, which can set the stage for offspring social position later in life. Here we examined maternal effects on dyadic aggressive interactions between immature (<12 years) chimpanzees. Specifically, we tested whether relative maternal rank predicted the probability of winning an aggressive interaction. We also examined maternal responses to aggressive interactions to determine whether maternal interventions explain interaction outcomes. Using a 12-year behavioural data set (2000–2011) from Gombe National Park, Tanzania, we found that relative maternal rank predicted the probability of winning aggressive interactions in male–male and male–female aggressive interactions: offspring were more likely to win if their mother outranked their opponent’s mother. Female–female aggressive interactions occurred infrequently (two interactions), so could not be analysed. The probability of winning was also higher for relatively older individuals in male–male interactions, and for males in male–female interactions. Maternal interventions were rare (7.3% of 137 interactions), suggesting that direct involvement does not explain the outcome for the vast majority of aggressive interactions. These findings provide important insight into the ontogeny of aggressive behaviour and early dominance relationships in wild apes and highlight a potential social advantage for offspring of higher-ranking mothers. This advantage may be particularly pronounced for sons, given male philopatry in chimpanzees and the potential for social status early in life to translate more directly to adult rank. PMID:25624528

  4. Autoinducer-2 influences interactions amongst pioneer colonizing streptococci in oral biofilms.

    PubMed

    Cuadra-Saenz, Giancarlo; Rao, Dhana L; Underwood, Adam J; Belapure, Sneha A; Campagna, Shawn R; Sun, Zhichao; Tammariello, Steven; Rickard, Alexander H

    2012-07-01

    Streptococcus gordonii and Streptococcus oralis are among the first bacterial species to colonize clean tooth surfaces. Both produce autoinducer-2 (AI-2): a family of inter-convertible cell-cell signal molecules synthesized by the LuxS enzyme. The overall aim of this work was to determine whether AI-2 alters interspecies interactions between S. gordonii DL1 and S. oralis 34 within dual-species biofilms in flowing human saliva. Based upon AI-2 bioluminescence assays, S. gordonii DL1 produced more AI-2 activity than S. oralis 34 in batch culture, and both were able to remove AI-2 activity from solution. In single-species, saliva-fed flowcell systems, S. oralis 34 formed scant biofilms that were similar to the luxS mutant. Conversely, S. gordonii DL1 formed confluent biofilms while the luxS mutant formed architecturally distinct biofilms that possessed twofold greater biovolume than the wild-type. Supplementing saliva with 0.1-10 nM chemically synthesized AI-2 (csAI-2) restored the S. gordonii DL1 luxS biofilm phenotype to that which was similar to the wild-type; above or below this concentration range, biofilms were architecturally similar to that formed by the luxS mutant. In dual-species biofilms, S. gordonii DL1 was always more abundant than S. oralis 34. Compared with dual-species, wild-type biofilms, the biovolume occupied by S. oralis 34 was reduced by greater than sevenfold when neither species produced AI-2. The addition of 1 nM csAI-2 to the dual-species luxS-luxS mutant biofilms re-established the biofilm phenotype to resemble that of the wild-type pair. Thus, this work demonstrates that AI-2 can alter the biofilm structure and composition of pioneering oral streptococcal biofilms. This may influence the subsequent succession of other species into oral biofilms and the ecology of dental plaque.

  5. Influence of shifting cultivation practices on soil-plant-beetle interactions.

    PubMed

    Ibrahim, Kalibulla Syed; Momin, Marcy D; Lalrotluanga, R; Rosangliana, David; Ghatak, Souvik; Zothansanga, R; Kumar, Nachimuthu Senthil; Gurusubramanian, Guruswami

    2016-08-01

    . The present study revealed the fact that shifting cultivation practice significantly affects the beetle species in terms of biodiversity pattern as well as evolutionary features. Spatiotemporal assessment of soil-plant-beetle interactions in shifting cultivation system and their influence in land degradation and ecology will be helpful in making biodiversity conservation decisions in the near future. PMID:27154839

  6. A Simple Approach for Boundary Improvement of Euler Diagrams.

    PubMed

    Simonetto, Paolo; Archambault, Daniel; Scheidegger, Carlos

    2016-01-01

    General methods for drawing Euler diagrams tend to generate irregular polygons. Yet, empirical evidence indicates that smoother contours make these diagrams easier to read. In this paper, we present a simple method to smooth the boundaries of any Euler diagram drawing. When refining the diagram, the method must ensure that set elements remain inside their appropriate boundaries and that no region is removed or created in the diagram. Our approach uses a force system that improves the diagram while at the same time ensuring its topological structure does not change. We demonstrate the effectiveness of the approach through case studies and quantitative evaluations.

  7. Influence of Interaction Between Qubits on Entanglement Sudden Death and Birth

    NASA Astrophysics Data System (ADS)

    Ji, Y. H.; Wang, Z. S.; Hu, J. J.

    2011-03-01

    Dynamic evolution of entanglement is studied for coupling two-qubit system in non-Markov environment in terms of concurrence. We find that the degree of entanglement depends on the initial quantum state of the system and the interaction between the two-qubit system and the environment. When the interaction between the qubits and the environment is completely symmetric, especially, the environment has no effect on the entanglement, where the decoherence is entirely resulted from the interaction between qubits. By controlling the coupling way of the interaction, thus, one may avoid the entanglement sudden death (ESD).

  8. Linking the Budyko framework and the Dunne diagram

    NASA Astrophysics Data System (ADS)

    Trancoso, Ralph; Larsen, Joshua R.; McAlpine, Clive; McVicar, Tim R.; Phinn, Stuart

    2016-04-01

    The spatial and temporal heterogeneity of climate, soils, topography and vegetation control the water and energy balances among catchments. Two well-known hydrological theories underpinning these processes are the Budyko framework and the Dunne diagram. Relating the scaling of water-energy balances (Budyko) and runoff generation mechanisms (Dunne) raises some important catchment comparison questions, namely: (i) how do streamflow characteristics vary according to the annual water and energy balances?; (ii) to what extent do biophysical drivers of runoff explain the observed streamflow variability?; and (iii) are there quantifiable process overlaps between these two approaches, and can they offer insights into the mechanics of catchment co-evolution? This study addresses these questions by analysing daily streamflow and precipitation time series data to quantify hydrological similarity across 355 catchments located along a tropical-temperate climatic gradient in eastern Australia. We used eight hydrological metrics to describe the hydrological response over a 33-year period (1980-2013). Hierarchical cluster, ordination analysis, the Budyko framework, and generalized additive models were used to evaluate hydrological similarity, extract the dominant response, and examine how the landscape and climatic characteristics of catchments influence the dominant streamflow response. The catchments were classified into five clusters based on the analysis of their hydrological characteristics and similarity, which vary along the annual water and energy balances gradient in the Budyko framework. Furthermore, we show that the streamflow similarity is explained by six catchment-specific biophysical factors that overlap with those described by the Dunne diagram for runoff generation, which in this case have the following order of relative importance: (i) Dryness Index; (ii) Fraction of Photosynthetically Active Radiation; (iii) Saturated Hydraulic Conductivity; (iv) Soil Depth; (v

  9. Mutual touch during mother-infant face-to-face still-face interactions: influences of interaction period and infant birth status.

    PubMed

    Mantis, Irene; Stack, Dale M; Ng, Laura; Serbin, Lisa A; Schwartzman, Alex E

    2014-08-01

    Contact behaviours such as touch, have been shown to be influential channels of nonverbal communication between mothers and infants. While existing research has examined the communicative roles of maternal or infant touch in isolation, mutual touch, whereby touching behaviours occur simultaneously between mothers and their infants, has yet to be examined. The present study was designed to investigate mutual touch during face-to-face interactions between mothers and their 5½-month-old fullterm (n=40), very low birth weight/preterm (VLBW/preterm; n=40) infants, and infants at psychosocial risk (n=41). Objectives were to examine: (1) how the quantitative and qualitative aspects of touch employed by mothers and their infants varied across the normal periods of the still-face (SF) procedure, and (2) how these were associated with risk status. Mutual touch was systematically coded using the mother-infant touch scale. Interactions were found to largely consist of mutual touch and one-sided touch plus movement, highlighting that active touching is pervasive during mother-infant interactions. Consistent with the literature, while the SF period did not negatively affect the amount of mutual touch engaged in for mothers and their fullterm infants and mothers and their infants at psychosocial risk, it did for mothers and their VLBW/preterm infants. Together, results illuminate how both mothers and infants participate in shaping and co-regulating their interactions through the use of touch and underscore the contribution of examining the influence of birth status on mutual touch.

  10. Drawing and Using Free Body Diagrams: Why It May Be Better Not to Decompose Forces

    ERIC Educational Resources Information Center

    Aviani, Ivica; Erceg, Nataša; Mešic, Vanes

    2015-01-01

    In this study we investigated how two different approaches to drawing free body diagrams influence the development of students' understanding of Newton's laws, including their ability to identify real forces. For this purpose we developed a 12-item two-tier multiple choice survey and conducted a quasiexperiment. This experiment included two groups…

  11. Process-Based Species Pools Reveal the Hidden Signature of Biotic Interactions Amid the Influence of Temperature Filtering.

    PubMed

    Lessard, Jean-Philippe; Weinstein, Ben G; Borregaard, Michael K; Marske, Katharine A; Martin, Danny R; McGuire, Jimmy A; Parra, Juan L; Rahbek, Carsten; Graham, Catherine H

    2016-01-01

    A persistent challenge in ecology is to tease apart the influence of multiple processes acting simultaneously and interacting in complex ways to shape the structure of species assemblages. We implement a heuristic approach that relies on explicitly defining species pools and permits assessment of the relative influence of the main processes thought to shape assemblage structure: environmental filtering, dispersal limitations, and biotic interactions. We illustrate our approach using data on the assemblage composition and geographic distribution of hummingbirds, a comprehensive phylogeny and morphological traits. The implementation of several process-based species pool definitions in null models suggests that temperature-but not precipitation or dispersal limitation-acts as the main regional filter of assemblage structure. Incorporating this environmental filter directly into the definition of assemblage-specific species pools revealed an otherwise hidden pattern of phylogenetic evenness, indicating that biotic interactions might further influence hummingbird assemblage structure. Such hidden patterns of assemblage structure call for a reexamination of a multitude of phylogenetic- and trait-based studies that did not explicitly consider potentially important processes in their definition of the species pool. Our heuristic approach provides a transparent way to explore patterns and refine interpretations of the underlying causes of assemblage structure. PMID:27277404

  12. Theoretical studies to elucidate the influence of magnetic dipolar interactions occurring in the magnetic nanoparticle systems, for biomedical applications

    NASA Astrophysics Data System (ADS)

    Osaci, M.; Cacciola, M.

    2016-02-01

    In recent years, the study of magnetic nanoparticles has been intensively developed not only for their fundamental theoretical interest, but also for their many technological applications, especially biomedical applications, ranging from contrast agents for magnetic resonance imaging to the deterioration of cancer cells via hyperthermia treatment. The theoretical and experimental research has shown until now that the magnetic dipolar interactions between nanoparticles can have a significant influence on the magnetic behaviour of the system. But, this influence is not well understood. It is clear that the magnetic dipolar interaction intensity is correlated with the nanoparticle concentration, volume fraction and magnetic moment orientations. In this paper, we try to understand the influence of magnetic dipolar interactions on the behaviour of magnetic nanoparticle systems, for biomedical applications. For the model, we considered spherical nanoparticles with uniaxial anisotropy and lognormal distribution of the sizes. The model involves a simulation stage of the spatial distribution and orientation of the nanoparticles and their easy axes of magnetic anisotropy, and an evaluation stage of the Néel relaxation time. To assess the Néel relaxation time, we are going to discretise and adapt, to the local magnetic field, the Coffey analytical solution for the equation Fokker-Planck describing the dynamics of magnetic moments of nanoparticles in oblique external magnetic field. There are three fundamental aspects of interest in our studies on the magnetic nanoparticles: their spatial & orientational distributions, concentrations and sizes.

  13. Phase Coexistence in a Dynamic Phase Diagram.

    PubMed

    Gentile, Luigi; Coppola, Luigi; Balog, Sandor; Mortensen, Kell; Ranieri, Giuseppe A; Olsson, Ulf

    2015-08-01

    Metastability and phase coexistence are important concepts in colloidal science. Typically, the phase diagram of colloidal systems is considered at the equilibrium without the presence of an external field. However, several studies have reported phase transition under mechanical deformation. The reason behind phase coexistence under shear flow is not fully understood. Here, multilamellar vesicle (MLV)-to-sponge (L3 ) and MLV-to-Lα transitions upon increasing temperature are detected using flow small-angle neutron scattering techniques. Coexistence of Lα and MLV phases at 40 °C under shear flow is detected by using flow NMR spectroscopy. The unusual rheological behavior observed by studying the lamellar phase of a non-ionic surfactant is explained using (2) H NMR and diffusion flow NMR spectroscopy with the coexistence of planar lamellar-multilamellar vesicles. Moreover, a dynamic phase diagram over a wide range of temperatures is proposed.

  14. Penguin diagrams for improved staggered fermions

    SciTech Connect

    Lee, Weonjong

    2005-01-01

    We calculate, at the one-loop level, penguin diagrams for improved staggered fermion operators constructed using various fat links. The main result is that diagonal mixing coefficients with penguin operators are identical between the unimproved operators and the improved operators using such fat links as Fat7, Fat7+Lepage, Fat7, HYP (I) and HYP (II). In addition, it turns out that the off-diagonal mixing vanishes for those constructed using fat links of Fat7, Fat7 and HYP (II). This is a consequence of the fact that the improvement by various fat links changes only the mixing with higher dimension operators and off-diagonal operators. The results of this paper, combined with those for current-current diagrams, provide complete matching at the one-loop level with all corrections of O(g{sup 2}) included.

  15. Prediction of boron carbon nitrogen phase diagram

    NASA Astrophysics Data System (ADS)

    Yao, Sanxi; Zhang, Hantao; Widom, Michael

    We studied the phase diagram of boron, carbon and nitrogen, including the boron-carbon and boron-nitrogen binaries and the boron-carbon-nitrogen ternary. Based on the idea of electron counting and using a technique of mixing similar primitive cells, we constructed many ''electron precise'' structures. First principles calculation is performed on these structures, with either zero or high pressures. For the BN binary, our calculation confirms that a rhmobohedral phase can be stablized at high pressure, consistent with some experimental results. For the BCN ternary, a new ground state structure is discovered and an Ising-like phase transition is suggested. Moreover, we modeled BCN ternary phase diagram and show continuous solubility from boron carbide to the boron subnitride phase.

  16. Phase diagram of a single lane roundabout

    NASA Astrophysics Data System (ADS)

    Echab, H.; Lakouari, N.; Ez-Zahraouy, H.; Benyoussef, A.

    2016-03-01

    Using the cellular automata model, we numerically study the traffic dynamic in a single lane roundabout system of four entry/exit points. The boundaries are controlled by the injecting rates α1, α2 and the extracting rate β. Both the system with and without Splitter Islands of width Lsp are considered. The phase diagram in the (α1 , β) space and its variation with the roundabout size, Pagg (i.e. the probability of aggressive entry), and Pexit (i.e. the probability of preferential exit) are constructed. The results show that the phase diagram in both cases consists of three phases: free flow, congested and jammed. However, as Lsp increases the free flow phase enlarges while the congested and jammed ones shrink. On the other hand, the short sized roundabout shows better performance in the free flow phase while the large one is more optimal in the congested phase. The density profiles are also investigated.

  17. Direct Measurement of the Fluid Phase Diagram.

    PubMed

    Bao, Bo; Riordon, Jason; Xu, Yi; Li, Huawei; Sinton, David

    2016-07-19

    The thermodynamic phase of a fluid (liquid, vapor or supercritical) is fundamental to all chemical processes, and the critical point is particularly important for supercritical chemical extraction. Conventional phase measurement methods require hours to obtain a single datum on the pressure and temperature diagram. Here, we present the direct measurement of the full pressure-temperature phase diagram, with 10 000 microwells. Orthogonal, linear, pressure and temperature gradients are obtained with 100 parallel microchannels (spanning the pressure range), each with 100 microwells (spanning the temperature range). The phase-mapping approach is demonstrated with both a pure substance (CO2) and a mixture (95% CO2 + 5% N2). Liquid, vapor, and supercritical regions are clearly differentiated, and the critical pressure is measured at 1.2% error with respect to the NIST standard. This approach provides over 100-fold improvement in measurement speed over conventional methods. PMID:27331613

  18. Lack of Influence of Substrate on Ligand Interaction with the Human Multidrug and Toxin Extruder, MATE1.

    PubMed

    Martínez-Guerrero, Lucy J; Morales, Mark; Ekins, Sean; Wright, Stephen H

    2016-09-01

    Multidrug and toxin extruder (MATE) 1 plays a central role in mediating renal secretion of organic cations, a structurally diverse collection of compounds that includes ∼40% of prescribed drugs. Because inhibition of transport activity of other multidrug transporters, including the organic cation transporter (OCT) 2, is influenced by the structure of the transported substrate, the present study screened over 400 drugs as inhibitors of the MATE1-mediated transport of four structurally distinct organic cation substrates: the commonly used drugs: 1) metformin and 2) cimetidine; and two prototypic cationic substrates, 3) 1-methyl-4-phenylpyridinium (MPP), and 4) the novel fluorescent probe, N,N,N-trimethyl-2-[methyl(7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)amino]ethanaminium iodide. Transport was measured in Chinese hamster ovary cells that stably expressed the human ortholog of MATE1. Comparison of the resulting inhibition profiles revealed no systematic influence of substrate structure on inhibitory efficacy. Similarly, IC50 values for 26 structurally diverse compounds revealed no significant influence of substrate structure on the kinetic interaction of inhibitor with MATE1. The IC50 data were used to generate three-dimensional quantitative pharmacophores that identified hydrophobic regions, H-bond acceptor sites, and an ionizable (cationic) feature as key determinants for ligand binding to MATE1. In summary, in contrast to the behavior observed with some other multidrug transporters, including OCT2, the results suggest that substrate identity exerts comparatively little influence on ligand interaction with MATE1. PMID:27418674

  19. Pair interactions in polyelectrolyte-nanoparticle systems: Influence of dielectric inhomogeneities and the partial dissociation of polymers and nanoparticles

    SciTech Connect

    Pryamitsyn, Victor; Ganesan, Venkat

    2015-10-28

    We study the effective pair interactions between two charged spherical particles in polyelectrolyte solutions using polymer self-consistent field theory. In a recent study [V. Pryamitsyn and V. Ganesan, Macromolecules 47, 6095 (2015)], we considered a model in which the particles possess fixed charge density, the polymers contain a prespecified amount of dissociated charges and, the dielectric constant of the solution was assumed to be homogeneous in space and independent of the polymer concentration. In this article, we present results extending our earlier model to study situations in which either or both the particle and the polymers possess partially dissociable groups. Additionally, we also consider the case when the dielectric constant of the solution depends on the local concentration of the polymers and when the particle’s dielectric constant is lower than that of the solvent. For each case, we quantify the polymer-mediated interactions between the particles as a function of the polymer concentrations and the degree of dissociation of the polymer and particles. Consistent with the results of our previous study, we observe that the polymer-mediated interparticle interactions consist of a short-range attraction and a long-range repulsion. The partial dissociablity of the polymer and particles was seen to have a strong influence on the strength of the repulsive portion of the interactions. Rendering the dielectric permittivity to be inhomogeneous has an even stronger effect on the repulsive interactions and results in changes to the qualitative nature of interactions in some parametric ranges.

  20. Influence of substituents on the nature of metal⋯π interaction and its cooperativity with halogen bond.

    PubMed

    Gao, Meng; Cheng, Jianbo; Yang, Xin; Li, Wenzuo; Xiao, Bo; Li, Qingzhong

    2015-08-01

    High-level quantum chemical calculations have been performed to investigate the influence of substituents on the metal-π interaction and its cooperative effect with halogen bond in C2X4⋯MCN⋯ClF (X = H, CN, CH3; M = Cu, Ag, Au). The strong electron-withdrawing group CN weakens the metal-π covalent interaction, while the weak electron-withdrawing group CH3 strengthens it. The metal-π covalent interaction is dominated by electrostatic energy although the AuCN complex has approximately equal electrostatic and polarization contributions. However, the metal-π covalent interaction is governed by polarization energy due to the CN substitution. A cooperative effect is found for the halogen bond and metal-π interactions in C2H4⋯MCN⋯ClF, while a diminutive effect occurs in the triads by the CN substituent. Orbital interaction analysis indicates that the strong electron-withdrawing group CN causes the C=C group vary from a stronger donor orbital to a stronger acceptor orbital.

  1. Influence of substituents on the nature of metal⋯π interaction and its cooperativity with halogen bond

    SciTech Connect

    Gao, Meng; Cheng, Jianbo E-mail: liqingzhong1990@sina.com; Yang, Xin; Li, Wenzuo; Xiao, Bo; Li, Qingzhong E-mail: liqingzhong1990@sina.com

    2015-08-07

    High-level quantum chemical calculations have been performed to investigate the influence of substituents on the metal—π interaction and its cooperative effect with halogen bond in C{sub 2}X{sub 4}⋯MCN⋯ClF (X = H, CN, CH{sub 3}; M = Cu, Ag, Au). The strong electron-withdrawing group CN weakens the metal—π covalent interaction, while the weak electron-withdrawing group CH{sub 3} strengthens it. The metal—π covalent interaction is dominated by electrostatic energy although the AuCN complex has approximately equal electrostatic and polarization contributions. However, the metal—π covalent interaction is governed by polarization energy due to the CN substitution. A cooperative effect is found for the halogen bond and metal—π interactions in C{sub 2}H{sub 4}⋯MCN⋯ClF, while a diminutive effect occurs in the triads by the CN substituent. Orbital interaction analysis indicates that the strong electron-withdrawing group CN causes the C=C group vary from a stronger donor orbital to a stronger acceptor orbital.

  2. The effect of rotation on Petersen Diagrams

    NASA Astrophysics Data System (ADS)

    Suárez, J. C.; Garrido, R.

    The well-known Petersen diagrams are a useful technique to constrain the mass and metallicity of models for double-mode radial pulsators. However, when moderately rotating stellar models are considered this method may fails. A preliminary study of the effect of rotation on the first overtone to fundamental period ratios is discussed for slow to moderate rotational velocities. The impact on the mass and metallicity determination is examined.

  3. Student Sensemaking with Science Diagrams in a Computer-Based Setting

    ERIC Educational Resources Information Center

    Furberg, Anniken; Kluge, Anders; Ludvigsen, Sten

    2013-01-01

    This paper reports on a study of students' conceptual sensemaking with science diagrams within a computer-based learning environment aimed at supporting collaborative learning. Through the microanalysis of students' interactions in a project about energy and heat transfer, we demonstrate "how" representations become productive social and cognitive…

  4. An exploration of motivations for two screen viewing, social interaction behaviors, and factors that influence viewing intentions.

    PubMed

    Shim, Hongjin; Oh, Poong; Song, Hyunjin; Lee, Yeonkyung

    2015-03-01

    This study explores whether, and how, motivations for two screen viewing predicted social interaction behaviors and subsequent viewing intention of TV programs. A total of 453 respondents who responded that they use social networking sites (SNSs) via smartphones and actively watch entertainment programs completed an online survey questionnaire. In agreement with uses and gratifications assumptions, motivations for TSV predicted distinctive sets of social interaction behaviors, which mediated the influence of motivations on viewing intentions. Respondents' two screen viewing was meaningfully related with social interaction, engagement with programs, information seeking, and passing time. Results suggest that two screen viewing could provide shared experiences nourishing social capital and reintegrate TV audiences by social adhesive resulting from TV with SNSs.

  5. An exploration of motivations for two screen viewing, social interaction behaviors, and factors that influence viewing intentions.

    PubMed

    Shim, Hongjin; Oh, Poong; Song, Hyunjin; Lee, Yeonkyung

    2015-03-01

    This study explores whether, and how, motivations for two screen viewing predicted social interaction behaviors and subsequent viewing intention of TV programs. A total of 453 respondents who responded that they use social networking sites (SNSs) via smartphones and actively watch entertainment programs completed an online survey questionnaire. In agreement with uses and gratifications assumptions, motivations for TSV predicted distinctive sets of social interaction behaviors, which mediated the influence of motivations on viewing intentions. Respondents' two screen viewing was meaningfully related with social interaction, engagement with programs, information seeking, and passing time. Results suggest that two screen viewing could provide shared experiences nourishing social capital and reintegrate TV audiences by social adhesive resulting from TV with SNSs. PMID:25751047

  6. Nonthermal Radio Emission and the HR Diagram

    NASA Technical Reports Server (NTRS)

    Gibson, D. M.

    1985-01-01

    Perhaps the most reliable indicator of non-radiative heating/momentum in a stellar atmosphere is the presence of nonthermal radio emission. To date, 77 normal stellar objects have been detected and identified as nonthermal sources. These stellar objects are tabulated herein. It is apparent that non-thermal radio emission is not ubiquitous across the HR diagram. This is clearly the case for the single stars; it is not as clear for the binaries unless the radio emission is associated with their late-type components. Choosing to make this association, the single stars and the late-type components are plotted together. The following picture emerges: (1) there are four locations on the HR diagram where non-thermal radio stars are found; (2) the peak incoherent 5 GHz luminosities show a suprisingly small range for stars within each class; (3) the fraction of stellar energy that escapes as radio emission can be estimated by comparing the integrated maximum radio luminosity to the bolometric luminosity; (4) there are no apparent differences in L sub R between binaries with two cool components, binaries with one hot and one cool component, and single stars for classes C and D; and (5) The late-type stars (classes B, C, and D) are located in parts of the HR diagram where there is reason to suspect that the surfaces of the stars are being braked with respect to their interiors.

  7. Refined phase diagram of boron nitride

    SciTech Connect

    Solozhenko, V.; Turkevich, V.Z.; Holzapfel, W.B.

    1999-04-15

    The equilibrium phase diagram of boron nitride thermodynamically calculated by Solozhenko in 1988 has been now refined on the basis of new experimental data on BN melting and extrapolation of heat capacities of BN polymorphs into high-temperature region using the adapted pseudo-Debye model. As compared with the above diagram, the hBN {l_reversible} cBN equilibrium line is displaced by 60 K toward higher temperatures. The hBN-cBN-L triple point has been calculated to be at 3480 {+-} 10 K and 5.9 {+-} 0.1 GPa, while the hBN-L-V triple point is at T = 3400 {+-} 20 K and p = 400 {+-} 20 Pa, which indicates that the region of thermodynamic stability of vapor in the BN phase diagram is extremely small. It has been found that the slope of the cBN melting curve is positive whereas the slope of hBN melting curve varies from positive between ambient pressure and 3.4 GPa to negative at higher pressures.

  8. Recognition and processing of logic diagrams

    NASA Astrophysics Data System (ADS)

    Darwish, Ahmed M.; Bashandy, Ahmed R.

    1996-03-01

    In this paper we present a vision system that is capable of interpreting schematic logic diagrams, i.e. determine the output as a logic function of the inputs. The system is composed of a number of modules each designed to perform a specific subtask. Each module bears a minor contribution in the form of a new mixture of known algorithms or extensions to handle actual real life image imperfections which researchers tend to ignore when they develop their theoretical foundations. The main contribution, thus, is not in any individual module, it is rather in their integration to achieve the target job. The system is organized more or less in a classical fashion. Aside from the image acquisition and preprocessing modules, interesting modules include: the segmenter, the identifier, the connector and the grapher. A good segmentation output is one reason for the success of the presented system. Several novelties exist in the presented approach. Following segmentation the type of each logic gate is determined and its topological connectivity. The logic diagram is then transformed to a directed acyclic graph in which the final node is the output logic gate. The logic function is then determined by backtracking techniques. The system is not only aimed at recognition applications. In fact its main usage may be to target other processing applications such as storage compression and graphics modification and manipulation of the diagram as is explained.

  9. The Critical Importance of Russell's Diagram

    NASA Astrophysics Data System (ADS)

    Gingerich, O.

    2013-04-01

    The idea of dwarf and giants stars, but not the nomenclature, was first established by Eijnar Hertzsprung in 1905; his first diagrams in support appeared in 1911. In 1913 Henry Norris Russell could demonstrate the effect far more strikingly because he measured the parallaxes of many stars at Cambridge, and could plot absolute magnitude against spectral type for many points. The general concept of dwarf and giant stars was essential in the galactic structure work of Harlow Shapley, Russell's first graduate student. In order to calibrate the period-luminosity relation of Cepheid variables, he was obliged to fall back on statistical parallax using only 11 Cepheids, a very sparse sample. Here the insight provided by the Russell diagram became critical. The presence of yellow K giant stars in globular clusters credentialed his calibration of the period-luminosity relation by showing that the calibrated luminosity of the Cepheids was comparable to the luminosity of the K giants. It is well known that in 1920 Shapley did not believe in the cosmological distances of Heber Curtis' spiral nebulae. It is not so well known that in 1920 Curtis' plot of the period-luminosity relation suggests that he didn't believe it was a physical relation and also he failed to appreciate the significance of the Russell diagram for understanding the large size of the Milky Way.

  10. Expanding application of the Wiggers diagram to teach cardiovascular physiology.

    PubMed

    Mitchell, Jamie R; Wang, Jiun-Jr

    2014-06-01

    Dr. Carl Wiggers' careful observations have provided a meaningful resource for students to learn how the heart works. Throughout the many years from his initial reports, the Wiggers diagram has been used, in various degrees of complexity, as a fundamental tool for cardiovascular instruction. Often, the various electrical and mechanical plots are the novice learner's first exposure to simulated data. As the various temporal relationships throughout a heartbeat could simply be memorized, the challenge for the cardiovascular instructor is to engage the learner so the underlying mechanisms governing the changing electrical and mechanical events are truly understood. Based on experience, we suggest some additions to the Wiggers diagram that are not commonly used to enhance cardiovascular pedagogy. For example, these additions could be, but are not limited to, introducing the concept of energy waves and their role in influencing pressure and flow in health and disease. Also, integrating concepts of exercise physiology, and the differences in cardiac function and hemodynamics between an elite athlete and normal subject, can have a profound impact on student engagement. In describing the relationship between electrical and mechanical events, the instructor may find the introduction of premature ventricular contractions as a useful tool to further understanding of this important principle. It is our hope that these examples can aid cardiovascular instructors to engage their learners and promote fundamental understanding at the expense of simple memorization.

  11. Expanding application of the Wiggers diagram to teach cardiovascular physiology

    PubMed Central

    Wang, Jiun-Jr

    2014-01-01

    Dr. Carl Wiggers' careful observations have provided a meaningful resource for students to learn how the heart works. Throughout the many years from his initial reports, the Wiggers diagram has been used, in various degrees of complexity, as a fundamental tool for cardiovascular instruction. Often, the various electrical and mechanical plots are the novice learner's first exposure to simulated data. As the various temporal relationships throughout a heartbeat could simply be memorized, the challenge for the cardiovascular instructor is to engage the learner so the underlying mechanisms governing the changing electrical and mechanical events are truly understood. Based on experience, we suggest some additions to the Wiggers diagram that are not commonly used to enhance cardiovascular pedagogy. For example, these additions could be, but are not limited to, introducing the concept of energy waves and their role in influencing pressure and flow in health and disease. Also, integrating concepts of exercise physiology, and the differences in cardiac function and hemodynamics between an elite athlete and normal subject, can have a profound impact on student engagement. In describing the relationship between electrical and mechanical events, the instructor may find the introduction of premature ventricular contractions as a useful tool to further understanding of this important principle. It is our hope that these examples can aid cardiovascular instructors to engage their learners and promote fundamental understanding at the expense of simple memorization. PMID:24913453

  12. Multiple contest experiences interact to influence each other's effect on subsequent contest decisions in a mangrove killifish.

    PubMed

    Hsu, Yuying; Huang, Yu-Yun; Wu, Ya-Ting

    2014-03-01

    Many animals modify behavioural decisions based on information they have previously acquired. Contest behaviour is often affected by previous contest experiences: individuals behave more and less aggressively after a victory and defeat, respectively (winner/loser effect). Individuals in the field sometimes encounter multiple competitors in quick succession, but whether these experiences interact to influence each other's importance is unclear. We tested five hypotheses for experience interaction (no interaction, retroactive interference, proactive interaction, reinforcement and diminishing returns) using Kryptolebias marmoratus. Focal individuals were paired up with opponents having the same 1-month contest outcome (1 month before the experiment), as this difference in actual or perceived fighting ability has been shown to affect the fish's response to new experiences. We gave the focal individual of a pair a winning or losing experience on day 1. Then both fish of the pair received the same winning, losing or no-contest experience on day 2. Then we organised fights between the two. The effect of a day-1 losing experience did depend on the fish's actual or perceived fighting ability: one-month losers readily showed loser effects from the day-1 losing experience, irrespective of the day-2 experience (i.e. no interaction between day-1 and day-2 experiences). One-month winners, however, only showed loser effects from a day-1 losing experience when the day-2 experience was also a loss (i.e. reinforcement). Day-1 winning experiences did not interact with day-2 experiences in 1-month losers or winners. Therefore, multiple experiences sometimes reinforce each other, but how they combine to influence behaviour depends on an individual's actual or perceived fighting ability. PMID:23760869

  13. On Public Influence on People’s Interactions with Ordinary Biodiversity

    PubMed Central

    Skandrani, Zina; Daniel, Lucie; Jacquelin, Lauriane; Leboucher, Gérard; Bovet, Dalila; Prévot, Anne-Caroline

    2015-01-01

    Besides direct impacts of urban biodiversity on local ecosystem services, the contact of city dwellers with urban nature in their everyday life could increase their awareness on conservation issues. In this paper, we focused on a particularly common animal urban species, the feral pigeon Columba livia. Through an observational approach, we examined behavioral interactions between city dwellers and this species in the Paris metropolis, France. We found that most people (mean: 81%) do not interact with pigeons. Further, interactions (either positive or negative) are context and age-dependent: children interact more than adults and the elderly, while people in tourist spots interact more than people in urban parks or in railway stations, a result that suggests that people interacting with pigeons are mostly tourists. We discuss these results in terms of public normative pressures on city dwellers’ access to and reconnection with urban nature. We call for caution in how urban species are publically portrayed and managed, given the importance of interactions with ordinary biodiversity for the fate of nature conservation. PMID:26154622

  14. Influence of salt bridge interactions on the gas-phase stability of DNA/peptide complexes

    NASA Astrophysics Data System (ADS)

    Alves, Sandra; Woods, Amina; Delvolvé, Alice; Tabet, Jean Claude

    2008-12-01

    Negative ion mode electrospray ionization mass spectrometry was used to study DNA duplexes-peptide interaction. In the present study, we show that peptides that contain two adjacent basic residues interact noncovalently with DNA single strand or duplex. Fragmentation of the complexes between peptides containing basic residues and DNA were studied under collisions and showed unexpected dissociation pathways, as previously reported for peptide-peptide interactions. The binary complexes are dissociated either along fragmentation of the covalent bonds of the peptide backbone and/or along the single DNA strand backbone cleavage without disruption of noncovalent interaction, which demonstrates the strong binding of peptide to the DNA strand. Sequential MS/MS and MSn were further performed on ternary complexes formed between duplexes and peptides to investigate the nature of interaction. The CID spectra showed as major pathway the disruption of the noncovalent interactions and the formation of binary complexes and single-strand ions, directed by the nucleic acid gas-phase acidity. Indeed, a preferential formation of complexes with thymidine containing single strands is observed. An alternative pathway is also detected, in which complexes are dissociated along the covalent bond of the peptide and/or DNA according to the basicity. Our experimental data suggest the presence of strong salt bridge interactions between DNA and peptides containing basic residues.

  15. Placing the Forces on Free-Body Diagrams.

    ERIC Educational Resources Information Center

    Sperry, Willard

    1994-01-01

    Discusses the problem of drawing free-body diagrams to analyze the conditions of static equilibrium. Presents a method based on the correct placement of the normal force on the body. Includes diagrams. (MVL)

  16. 75 FR 61512 - Outer Continental Shelf Official Protraction Diagrams

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-05

    ... Outer Continental Shelf Official Protraction Diagrams (OPDs) located within Atlantic Ocean areas, with... Bureau of Ocean Energy Management, Regulation and Enforcement Outer Continental Shelf Official Protraction Diagrams AGENCY: Bureau of Ocean Energy Management, Regulation and Enforcement, Interior....

  17. Proof test diagrams for Zerodur glass-ceramic

    NASA Technical Reports Server (NTRS)

    Tucker, D. S.

    1991-01-01

    Proof test diagrams for Zerodur glass-ceramics are calculated from available fracture mechanics data. It is shown that the environment has a large effect on minimum time-to-failure as predicted by proof test diagrams.

  18. Soma-to-germline interactions during Drosophila oogenesis are influenced by dose-sensitive interactions between cut and the genes cappuccino, ovarian tumor and agnostic.

    PubMed Central

    Jackson, S M; Berg, C A

    1999-01-01

    The cut gene of Drosophila melanogaster encodes a homeodomain protein that regulates a soma-to-germline signaling pathway required for proper morphology of germline cells during oogenesis. cut is required solely in somatic follicle cells, and when cut function is disrupted, membranes separating adjacent nurse cells break down and the structural integrity of the actin cytoskeleton is compromised. To understand the mechanism by which cut expression influences germline cell morphology, we determined whether binucleate cells form by defective cytokinesis or by fusion of adjacent cells. Egg chambers produced by cut, cappuccino, and chickadee mutants contained binucleate cells in which ring canal remnants stained with antibodies against Hu-li tai shao and Kelch, two proteins that are added to ring canals after cytokinesis is complete. In addition, defects in egg chamber morphology were observed only in middle to late stages of oogenesis, suggesting that germline cell cytokineses were normal in these mutants. cut exhibited dose-sensitive genetic interactions with cappuccino but not with chickadee or other genes that regulate cytoskeletal function, including armadillo, spaghetti squash, quail, spire, Src64B, and Tec29A. Genomic regions containing genes that cooperate with cut were identified by performing a second-site noncomplementing screen using a collection of chromosomal deficiencies. Sixteen regions that interact with cut during oogenesis and eight regions that interact during the development of other tissues were identified. Genetic interactions between cut and the ovarian tumor gene were identified as a result of the screen. In addition, the gene agnostic was found to be required during oogenesis, and genetic interactions between cut and agnostic were revealed. These results demonstrate that a signaling pathway regulating the morphology of germline cells is sensitive to genetic doses of cut and the genes cappuccino, ovarian tumor, and agnostic. Since these genes

  19. Forcing an entire bifurcation diagram: Case studies in chemical oscillators

    NASA Astrophysics Data System (ADS)

    Kevrekidis, I. G.; Aris, R.; Schmidt, L. D.

    1986-12-01

    We study the finite amplitude periodic forcing of chemical oscillators. In particular, we examine systems that, when autonomous, (i.e. for zero forcing amplitude) exhibit a single stable oscillation. Using one of the system parameters as a forcing variable by varying it periodically, we show through extensive numerical work how the bifurcation diagram of the autonomous system with respect to this parameter affects the qualitative response of the full forced system. As the forcing variable oscillates around its midpoint, its instantaneous values may cross points (such as Hopf bifurcation poiints) of the autonomous bifurcation diagram so that the characterization of the system as a simple forced oscillator is no longer valid. Such a neighboring Hopf bifurcation of the unforced system is found to set the scene for the interaction of resonance horns and the loss of tori in the full forced system as the amplitude of the forcing grows. Our test case presented here is the Continuous Stirred Tank Reactor (CSTR) with periodically forced coolant temperature.

  20. Understanding the H -T phase diagram of the monoaxial helimagnet

    NASA Astrophysics Data System (ADS)

    Laliena, Victor; Campo, Javier; Kousaka, Yusuke

    2016-09-01

    Some unexpected features of the phase diagram of the monoaxial helimagnet in presence of an applied magnetic field perpendicular to the chiral axis are theoretically predicted. A rather general Hamiltonian with long-range Heisenberg exchange and Dzyaloshinskii-Moriya interactions is considered. The continuum limit simplifies the free energy, which contains only a few parameters which in principle are determined by the many parameters of the Hamiltonian, although in practice they may be tuned to fit the experiments. The phase diagram contains a chiral soliton lattice phase and a forced ferromagnetic phase separated by a line of phase transitions, which are of second order at low T and of first order in the vicinity of the zero-field ordering temperature, and are separated by a tricritical point. A highly nonlinear chiral soliton lattice, in which many harmonics contribute appreciably to the spatial modulation of the local magnetic moment, develops only below the tricritical temperature, and in this case, the scaling shows a logarithmic behavior similar to that at T =0 , which is a universal feature of the chiral soliton lattice. Below the tricritical temperature, the normalized soliton density curves are found to be independent of T , in agreement with the experimental results of magnetorresistance curves, while above the tricritical temperature they show a noticeable temperature dependence. The implications in the interpretation of experimental results of CrNb3S6 are discussed.

  1. Glass and liquid phase diagram of a polyamorphic monatomic system

    NASA Astrophysics Data System (ADS)

    Reisman, Shaina; Giovambattista, Nicolas

    2013-02-01

    We perform out-of-equilibrium molecular dynamics (MD) simulations of a monatomic system with Fermi-Jagla (FJ) pair potential interactions. This model system exhibits polyamorphism both in the liquid and glass state. The two liquids, low-density (LDL) and high-density liquid (HDL), are accessible in equilibrium MD simulations and can form two glasses, low-density (LDA) and high-density amorphous (HDA) solid, upon isobaric cooling. The FJ model exhibits many of the anomalous properties observed in water and other polyamorphic liquids and thus, it is an excellent model system to explore qualitatively the thermodynamic properties of such substances. The liquid phase behavior of the FJ model system has been previously characterized. In this work, we focus on the glass behavior of the FJ system. Specifically, we perform systematic isothermal compression and decompression simulations of LDA and HDA at different temperatures and determine "phase diagrams" for the glass state; these phase diagrams varying with the compression/decompression rate used. We obtain the LDA-to-HDA and HDA-to-LDA transition pressure loci, PLDA-HDA(T) and PHDA-LDA(T), respectively. In addition, the compression-induced amorphization line, at which the low-pressure crystal (LPC) transforms to HDA, PLPC-HDA(T), is determined. As originally proposed by Poole et al. [Phys. Rev. E 48, 4605 (1993)], 10.1103/PhysRevE.48.4605 simulations suggest that the PLDA-HDA(T) and PHDA-LDA(T) loci are extensions of the LDL-to-HDL and HDL-to-LDL spinodal lines into the glass domain. Interestingly, our simulations indicate that the PLPC-HDA(T) locus is an extension, into the glass domain, of the LPC metastability limit relative to the liquid. We discuss the effects of compression/decompression rates on the behavior of the PLDA-HDA(T), PHDA-LDA(T), PLPC-HDA(T) loci. The competition between glass polyamorphism and crystallization is also addressed. At our "fast rate," crystallization can be partially suppressed and the

  2. Glass and liquid phase diagram of a polyamorphic monatomic system.

    PubMed

    Reisman, Shaina; Giovambattista, Nicolas

    2013-02-14

    We perform out-of-equilibrium molecular dynamics (MD) simulations of a monatomic system with Fermi-Jagla (FJ) pair potential interactions. This model system exhibits polyamorphism both in the liquid and glass state. The two liquids, low-density (LDL) and high-density liquid (HDL), are accessible in equilibrium MD simulations and can form two glasses, low-density (LDA) and high-density amorphous (HDA) solid, upon isobaric cooling. The FJ model exhibits many of the anomalous properties observed in water and other polyamorphic liquids and thus, it is an excellent model system to explore qualitatively the thermodynamic properties of such substances. The liquid phase behavior of the FJ model system has been previously characterized. In this work, we focus on the glass behavior of the FJ system. Specifically, we perform systematic isothermal compression and decompression simulations of LDA and HDA at different temperatures and determine "phase diagrams" for the glass state; these phase diagrams varying with the compression/decompression rate used. We obtain the LDA-to-HDA and HDA-to-LDA transition pressure loci, P(LDA-HDA)(T) and P(HDA-LDA)(T), respectively. In addition, the compression-induced amorphization line, at which the low-pressure crystal (LPC) transforms to HDA, P(LPC-HDA)(T), is determined. As originally proposed by Poole et al. [Phys. Rev. E 48, 4605 (1993)] simulations suggest that the P(LDA-HDA)(T) and P(HDA-LDA)(T) loci are extensions of the LDL-to-HDL and HDL-to-LDL spinodal lines into the glass domain. Interestingly, our simulations indicate that the P(LPC-HDA)(T) locus is an extension, into the glass domain, of the LPC metastability limit relative to the liquid. We discuss the effects of compression/decompression rates on the behavior of the P(LDA-HDA)(T), P(HDA-LDA)(T), P(LPC-HDA)(T) loci. The competition between glass polyamorphism and crystallization is also addressed. At our "fast rate," crystallization can be partially suppressed and the glass

  3. Pathway Based Analysis of Genes and Interactions Influencing Porcine Testis Samples from Boars with Divergent Androstenone Content in Back Fat

    PubMed Central

    Sahadevan, Sudeep; Gunawan, Asep; Tholen, Ernst; Große-Brinkhaus, Christine; Tesfaye, Dawit; Schellander, Karl; Hofmann-Apitius, Martin; Cinar, Mehmet Ulas; Uddin, Muhammad Jasim

    2014-01-01

    One of the primary factors contributing to boar taint is the level of androstenone in porcine adipose tissues. A majority of the studies performed to identify candidate biomarkers for the synthesis of androstenone in testis tissues follow a reductionist approach, identifying and studying the effect of biomarkers individually. Although these studies provide detailed information on individual biomarkers, a global picture of changes in metabolic pathways that lead to the difference in androstenone synthesis is still missing. The aim of this work was to identify major pathways and interactions influencing steroid hormone synthesis and androstenone biosynthesis using an integrative approach to provide a bird’s eye view of the factors causing difference in steroidogenesis and androstenone biosynthesis. For this purpose, we followed an analysis procedure merging together gene expression data from boars with divergent levels of androstenone and pathway mapping and interaction network retrieved from KEGG database. The interaction networks were weighted with Pearson correlation coefficients calculated from gene expression data and significant interactions and enriched pathways were identified based on these networks. The results show that 1,023 interactions were significant for high and low androstenone animals and that a total of 92 pathways were enriched for significant interactions. Although published articles show that a number of these enriched pathways were activated as a result of downstream signaling of steroid hormones, we speculate that the significant interactions in pathways such as glutathione metabolism, sphingolipid metabolism, fatty acid metabolism and significant interactions in cAMP-PKA/PKC signaling might be the key factors determining the difference in steroidogenesis and androstenone biosynthesis between boars with divergent androstenone levels in our study. The results and assumptions presented in this study are from an in-silico analysis done at the

  4. Pathway based analysis of genes and interactions influencing porcine testis samples from boars with divergent androstenone content in back fat.

    PubMed

    Sahadevan, Sudeep; Gunawan, Asep; Tholen, Ernst; Große-Brinkhaus, Christine; Tesfaye, Dawit; Schellander, Karl; Hofmann-Apitius, Martin; Cinar, Mehmet Ulas; Uddin, Muhammad Jasim

    2014-01-01

    One of the primary factors contributing to boar taint is the level of androstenone in porcine adipose tissues. A majority of the studies performed to identify candidate biomarkers for the synthesis of androstenone in testis tissues follow a reductionist approach, identifying and studying the effect of biomarkers individually. Although these studies provide detailed information on individual biomarkers, a global picture of changes in metabolic pathways that lead to the difference in androstenone synthesis is still missing. The aim of this work was to identify major pathways and interactions influencing steroid hormone synthesis and androstenone biosynthesis using an integrative approach to provide a bird's eye view of the factors causing difference in steroidogenesis and androstenone biosynthesis. For this purpose, we followed an analysis procedure merging together gene expression data from boars with divergent levels of androstenone and pathway mapping and interaction network retrieved from KEGG database. The interaction networks were weighted with Pearson correlation coefficients calculated from gene expression data and significant interactions and enriched pathways were identified based on these networks. The results show that 1,023 interactions were significant for high and low androstenone animals and that a total of 92 pathways were enriched for significant interactions. Although published articles show that a number of these enriched pathways were activated as a result of downstream signaling of steroid hormones, we speculate that the significant interactions in pathways such as glutathione metabolism, sphingolipid metabolism, fatty acid metabolism and significant interactions in cAMP-PKA/PKC signaling might be the key factors determining the difference in steroidogenesis and androstenone biosynthesis between boars with divergent androstenone levels in our study. The results and assumptions presented in this study are from an in-silico analysis done at the

  5. Recursive graphical construction of feynman diagrams and their multiplicities in straight phi(4) and straight phi2A theory

    PubMed

    Kleinert; Pelster; Kastening; Bachmann

    2000-08-01

    The free energy of a field theory can be considered as a functional of the free correlation function. As such it obeys a nonlinear functional differential equation that can be turned into a recursion relation. This is solved order by order in the coupling constant to find all connected vacuum diagrams with their proper multiplicities. The procedure is applied to a multicomponent scalar field theory with a straight phi(4) self-interaction and then to a theory of two scalar fields straight phi and A with an interaction straight phi2A. All Feynman diagrams with external lines are obtained from functional derivatives of the connected vacuum diagrams with respect to the free correlation function. Finally, the recursive graphical construction is automatized by computer algebra with the help of a unique matrix notation for the Feynman diagrams.

  6. Harnessing nanotopography and integrin-matrix interactions to influence stem cell fate

    NASA Astrophysics Data System (ADS)

    Dalby, Matthew J.; Gadegaard, Nikolaj; Oreffo, Richard O. C.

    2014-06-01

    Stem cells respond to nanoscale surface features, with changes in cell growth and differentiation mediated by alterations in cell adhesion. The interaction of nanotopographical features with integrin receptors in the cells' focal adhesions alters how the cells adhere to materials surfaces, and defines cell fate through changes in both cell biochemistry and cell morphology. In this Review, we discuss how cell adhesions interact with nanotopography, and we provide insight as to how materials scientists can exploit these interactions to direct stem cell fate and to understand how the behaviour of stem cells in their niche can be controlled. We expect knowledge gained from the study of cell-nanotopography interactions to accelerate the development of next-generation stem cell culture materials and implant interfaces, and to fuel discovery of stem cell therapeutics to support regenerative therapies.

  7. Geometric influence on Ruderman-Kittel-Kasuya-Yosida interactions in zigzag carbon nanotubes.

    PubMed

    Bunder, J E; Hill, James M

    2012-04-21

    We derive an analytic description of the spin susceptibility in finite length zigzag carbon nanotubes (CNT) with chirality (n, 0). The spin susceptibility is proportional to the Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions which describes indirect carrier mediated exchange coupling between localized magnetic moments. We show that the strongest RKKY interactions are along the edges of the nanotube and in the thermodynamic limit at half filling with spin symmetry the shape of the susceptibility curve about the edge of the CNT can be determined solely by the lattice geometry represented by the parameter n and a parameter L which describes the nanotube length. We also show that the introduction of Zeeman splitting or doping may have no effect on the spin susceptibility, provided n is small. A detailed knowledge of magnetic interactions, such as RKKY interactions, in CNT is of vital importance to the development of nanotechnology applications.

  8. Influence of strong field vacuum polarization on gravitational-electromagnetic wave interaction

    SciTech Connect

    Forsberg, M.; Brodin, G.; Papadopoulos, D.

    2010-07-15

    The interaction between gravitational and electromagnetic waves in the presence of a static magnetic field is studied. The field strength of the static field is allowed to surpass the Schwinger critical field, such that the QED effects of vacuum polarization and magnetization are significant. Equations governing the interaction are derived and analyzed. It turns out that the energy conversion from gravitational to electromagnetic waves can be significantly altered due to the QED effects. The consequences of our results are discussed.

  9. The influence of interactive technology on student performance in an Oklahoma secondary Biology I program

    NASA Astrophysics Data System (ADS)

    Feltman, Vallery

    Over the last decade growth in technologies available to teach students and enhance curriculum has become an important consideration in the educational system. The profile of today's secondary students have also been found to be quite different than those of the past. Their learning styles and preferences are issues that should be addressed by educators. With the growth and availability of new technologies students are increasingly expecting to use these as learning tools in their classrooms. This study investigates how interactive technology may impact student performance. This study specifically focuses on the use of the Apple Ipad in 4 Biology I classrooms. This study used an experimental mixed method design to examine how using Ipads for learning impacted student achievement, motivation to learn, and learning strategies. Qualitatively the study examined observed student behaviors and student perceptions regarding the use of interactive technologies. Data was analyzed using descriptive statistics, t-tests, 2-way ANOVAs, and qualitative analysis. Quantitatively the results revealed no significant difference between students who used the interactive technology to learn and those who did not. Qualitative data revealed behaviors indicative of being highly engaged with the subject matter and the development of critical thinking skills which may improve student performance. Student perceptions also revealed overall positive experiences with using interactive technology in the classroom. It is recommended that further studies be done to look at using interactive technologies for a longer period of time using multiple subjects areas. This would provide a more in-depth exploration of interactive technologies on student achievement.

  10. Differences in the influence of the interaction between acetylsalicylic acid and salicylic acid on platelet function in whole blood and isolated platelets: influence of neutrophils.

    PubMed

    González-Correa, J A; Muñoz-Marín, J; López-Villodres, J A; Navas, M D; Guerrero, A; Torres, J A; De La Cruz, J P

    2007-08-01

    The aim of this study was to characterize the influence of the interaction between acetylsalicylic acid (ASA) and salicylic acid (SA) on the inhibition by ASA of platelet aggregation in platelets isolated from whole blood, and to determine whether leukocytes influence this pharmacological interaction. This in vitro study was done in human blood from which we prepared samples of whole blood, platelet-rich plasma (PRP), PRP plus mononuclear leukocytes, and PRP plus neutrophils. The variables recorded were maximum platelet aggregation intensity, thromboxane B2 (TxB2) production, and nitric oxide (NO) production (N=10 different samples in each type of experiment). Different concentrations of ASA and SA were incubated with all samples. In PRP, the concentration of ASA that inhibited maximum aggregation by 50% (IC50) (281+/-16microM) increased with increasing SA concentration to a maximum of more than 2mM when 500microM SA was used. In whole blood, the IC50 for ASA (24.9+/-1.2microM) decreased with decreasing SA concentrations to 7.9+/-0.8microM with 50microM SA and 15.6+/-0.9microM with 125microM SA, and increased to 46.2+/-2.6microM with 250microM SA and 96.3+/-7.2microM with 500microM SA. In experiments with PRP+neutrophils the IC50 of ASA increased in the presence of all concentrations of SA. The antagonistic interactions were also reflected in the changes in TxB2 production in all samples. In samples of neutrophils incubated with ASA, the curve for NO production was shifted to the right, a finding that paralleled the changes in platelet aggregation. In conclusion, the influence of the interaction between ASA and its metabolite SA on platelet aggregation difference depending on the type of sample, and was antagonistic in PRP but partially agonistic in whole blood. Nitric oxide synthesis showed an additive effect of the two compounds.

  11. Phase diagram of a rotating Bose-Einstein condensate with anharmonic confinement

    SciTech Connect

    Jackson, A.D.; Kavoulakis, G.M.; Lundh, E.

    2004-05-01

    We examine the phase diagram of an effectively repulsive Bose-Einstein condensate of atoms that rotates in a quadratic-plus-quartic potential. With use of a variational method we identify the three possible phases of the system as a function of the rotational frequency of the trap and of the coupling constant. The derived phase diagram is shown to be universal and partly exact in the limit of weak interactions and small anharmonicity. The variational results are found to be consistent with numerical solutions of the Gross-Pitaevskii equation.

  12. Natural representations: diagram and text in Darwin's "On the origin of species".

    PubMed

    Brink-Roby, Heather

    2009-01-01

    This article examines Darwin's use of diagram and text in the "Origin" by focusing on their interacting roles in his discussion of natural relations, extinction, and time. Each medium presented opportunities and challenges that depend on the topic in question; indeed, a medium's dimensionality could undermine one claim and make self-evident another. While Darwin divides representational labor between diagram and text, he also creates a constitutive interplay between media. The resulting dynamic alliance of form and content recalls his early evolutionary reflections on representation; image and word could be used not simply to argue for, but also as evidence of, his theory.

  13. Microscopic theory for the charge stability diagram of coupled quantum dot systems

    NASA Astrophysics Data System (ADS)

    Yang, Shuo; Wang, Xin; Das Sarma, Sankar

    2011-03-01

    We present a quantitative microscopic theory for the charge stability diagram of coupled quantum dot systems. Using the configuration interaction method we obtain a generalized Hubbard model, from which the charge stability diagram is calculated and compared with experiments. We establish an exact connection between experimental measurements and the microscopic theory, and predict some experimentally observable quantum effects. We also map the classical capacitance model to the extended Hubbard model, and argue that the effect of spin-exchange and various hopping terms cannot be expressed in the capacitance model. This work is supported by LPS-CMTC, IARPA, and CNAM.

  14. The Problem of Labels in E-Assessment of Diagrams

    ERIC Educational Resources Information Center

    Jayal, Ambikesh; Shepperd, Martin

    2009-01-01

    In this article we explore a problematic aspect of automated assessment of diagrams. Diagrams have partial and sometimes inconsistent semantics. Typically much of the meaning of a diagram resides in the labels; however, the choice of labeling is largely unrestricted. This means a correct solution may utilize differing yet semantically equivalent…

  15. Science Visual Literacy: Learners' Perceptions and Knowledge of Diagrams

    ERIC Educational Resources Information Center

    McTigue, Erin M.; Flowers, Amanda C.

    2011-01-01

    Constructing meaning from science texts relies not only on comprehending the words but also the diagrams and other graphics. The goal of this study was to explore elementary students' perceptions of science diagrams and their skills related to diagram interpretation. 30 students, ranging from second grade through middle school, completed a diagram…

  16. Differential Cognitive and Affective Responses to Flow Diagrams in Science

    ERIC Educational Resources Information Center

    Holliday, William G.; And Others

    1977-01-01

    Describes a study in which tenth-grade biology students who were low verbal performers scored significantly higher on achievement tests when provided with picture-word diagrams of biological concepts than when provided with block-word diagrams. Students and teachers also preferred picture-word diagrams as indicated by a questionnaire. (MLH)

  17. Students' Learning Activities While Studying Biological Process Diagrams

    ERIC Educational Resources Information Center

    Kragten, Marco; Admiraal, Wilfried; Rijlaarsdam, Gert

    2015-01-01

    Process diagrams describe how a system functions (e.g. photosynthesis) and are an important type of representation in Biology education. In the present study, we examined students' learning activities while studying process diagrams, related to their resulting comprehension of these diagrams. Each student completed three learning tasks. Verbal…

  18. The BDNF Val66Met Polymorphism Interacts with Maternal Parenting Influencing Adolescent Depressive Symptoms: Evidence of Differential Susceptibility Model.

    PubMed

    Zhang, Leilei; Li, Zhi; Chen, Jie; Li, Xinying; Zhang, Jianxin; Belsky, Jay

    2016-03-01

    Although depressive symptoms are common during adolescence, little research has examined gene-environment interaction on youth depression. This study chose the brain-derived neurotrophic factor (BDNF) gene, tested the interaction between a functional polymorphism resulting amino acid substitution of valine (Val) to methionine (Met) in the proBDNF protein at codon 66 (Val66Met), and maternal parenting on youth depressive symptoms in a sample of 780 community adolescents of Chinese Han ethnicity (aged 11-17, M = 13.6, 51.3 % females). Participants reported their depressive symptoms and perceived maternal parenting. Results indicated the BDNF Val66Met polymorphism significantly moderated the influence of maternal warmth-reasoning, but not harshness-hostility, on youth depressive symptoms. Confirmatory model evaluation indicated that the interaction effect involving warmth-reasoning conformed to the differential-susceptibility rather than diathesis-stress model of person-X-environment interaction. Thus, Val carriers experienced less depressive symptoms than Met homozygotes when mothering was more positive but more symptoms when mothering was less positive. The findings provided evidence in support of the differential susceptibility hypothesis of youth depressive symptoms and shed light on the importance of examining the gene-environment interaction from a developmental perspective.

  19. Apolipoprotein A2 polymorphism interacts with intakes of dairy foods to influence body weight in 2 U.S. populations.

    PubMed

    Smith, Caren E; Tucker, Katherine L; Arnett, Donna K; Noel, Sabrina E; Corella, Dolores; Borecki, Ingrid B; Feitosa, Mary F; Aslibekyan, Stella; Parnell, Laurence D; Lai, Chao-Qiang; Lee, Yu-Chi; Ordovás, José M

    2013-12-01

    The interaction between a functional apolipoprotein A2 gene (APOA2) variant and saturated fatty acids (SFAs) for the outcome of body mass index (BMI) is among the most widely replicated gene-nutrient interactions. Whether this interaction can be extrapolated to food-based sources of SFAs, specifically dairy foods, is unexplored. Cross-sectional analyses were performed in 2 U.S. population-based samples. We evaluated interactions between dairy foods and APOA2 -265T > C (rs5082) for BMI in the Boston Puerto Rican Health Study (n = 955) and tested for replication in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) study (n = 1116). Dairy products were evaluated as total dairy, higher-fat dairy (>1%), and low-fat dairy (≤ 1%) in servings per day, dichotomized into high and low based on each population median and also as continuous variables. We identified a statistically significant interaction between the APOA2 -265T > C variant and higher-fat dairy food intake in the Boston Puerto Ricans (P-interaction = 0.028) and replicated this relation in the GOLDN study (P-interaction = 0.001). In both groups, individuals with the previously demonstrated SFA-sensitive genotype (CC) who consumed a greater amount of higher-fat dairy foods had greater BMI (P = 0.013 in Boston Puerto Ricans; P = 0.0007 in GOLDN women) compared with those consuming less of the higher-fat dairy foods. The results expand the understanding of the metabolic influence of dairy products, an important food group for which variable relations to body weight may be in part genetically based. Moreover, these findings suggest that other strongly demonstrated gene-nutrient relations might be investigated through appropriate food-based, translatable avenues and may be relevant to dietary management of obesity.

  20. Environmental influences on maize-Aspergillus flavus interactions and aflatoxin production.

    PubMed

    Fountain, Jake C; Scully, Brian T; Ni, Xinzhi; Kemerait, Robert C; Lee, Robert D; Chen, Zhi-Yuan; Guo, Baozhu

    2014-01-01

    Since the early 1960s, the fungal pathogen Aspergillus flavus (Link ex Fr.) has been the focus of intensive research due to the production of carcinogenic and highly toxic secondary metabolites collectively known as aflatoxins following pre-harvest colonization of crops. Given this recurrent problem and the occurrence of a severe aflatoxin outbreak in maize (Zea mays L.), particularly in the Southeast U.S. in the 1977 growing season, a significant research effort has been put forth to determine the nature of the interaction occurring between aflatoxin production, A. flavus, environment and its various hosts before harvest. Many studies have investigated this interaction at the genetic, transcript, and protein levels, and in terms of fungal biology at either pre- or post-harvest time points. Later experiments have indicated that the interaction and overall resistance phenotype of the host is a quantitative trait with a relatively low heritability. In addition, a high degree of environmental interaction has been noted, particularly with sources of abiotic stress for either the host or the fungus such as drought or heat stresses. Here, we review the history of research into this complex interaction and propose future directions for elucidating the relationship between resistance and susceptibility to A. flavus colonization, abiotic stress, and its relationship to oxidative stress in which aflatoxin production may function as a form of antioxidant protection to the producing fungus. PMID:24550905

  1. Does the Type of Event Influence How User Interactions Evolve on Twitter?

    PubMed Central

    del Val, Elena; Rebollo, Miguel; Botti, Vicente

    2015-01-01

    The number of people using on-line social networks as a new way of communication is continually increasing. The messages that a user writes in these networks and his/her interactions with other users leave a digital trace that is recorded. Thanks to this fact and the use of network theory, the analysis of messages, user interactions, and the complex structures that emerge is greatly facilitated. In addition, information generated in on-line social networks is labeled temporarily, which makes it possible to go a step further analyzing the dynamics of the interaction patterns. In this article, we present an analysis of the evolution of user interactions that take place in television, socio-political, conference, and keynote events on Twitter. Interactions have been modeled as networks that are annotated with the time markers. We study changes in the structural properties at both the network level and the node level. As a result of this analysis, we have detected patterns of network evolution and common structural features as well as differences among the events. PMID:25961305

  2. Does the type of event influence how user interactions evolve on Twitter?

    PubMed

    del Val, Elena; Rebollo, Miguel; Botti, Vicente

    2015-01-01

    The number of people using on-line social networks as a new way of communication is continually increasing. The messages that a user writes in these networks and his/her interactions with other users leave a digital trace that is recorded. Thanks to this fact and the use of network theory, the analysis of messages, user interactions, and the complex structures that emerge is greatly facilitated. In addition, information generated in on-line social networks is labeled temporarily, which makes it possible to go a step further analyzing the dynamics of the interaction patterns. In this article, we present an analysis of the evolution of user interactions that take place in television, socio-political, conference, and keynote events on Twitter. Interactions have been modeled as networks that are annotated with the time markers. We study changes in the structural properties at both the network level and the node level. As a result of this analysis, we have detected patterns of network evolution and common structural features as well as differences among the events. PMID:25961305

  3. Influence of the dipole interaction on the direction of the magnetization in thin ferromagnetic films

    NASA Astrophysics Data System (ADS)

    Moschel, A.; Usadel, K. D.

    1994-11-01

    The magnetization of thin films depends in a very sensitive way on surface anisotropy fields which often favor a perpendicular orientation and on the dipole interaction which favors an in-plane magnetization. A temperature driven transition from one to the other orientation has been observed experimentally. In order to understand this behavior theoretically we performed detailed calculations of the magnetization of very thin films (thickness of up to 5 layers) within a quantum mechanical mean field approach. A surface anisotropy that favors a perpendicular orientation and a long range dipole interaction were taken into account. It is shown that these competing interactions for certain values of the parameters may result in a temperature driven switching transition from an out-of plane to an in-plane ordered state. Varying the strength of the dipole interaction we found that the switching temperature is a very sensitive function of the ratio of these two competing interactions. A perpendicular ground state magnetization of the firm is only found for values of the surface anisotropy which are larger than a critical surface anisotropy value. The reorientation of the magnetization vector has its physical origin in an entropy increase of the system when going from a perpendicular to an in-plan ordered state.

  4. Influence of World and Gravity Model Selection on Surface Interacting Vehicle Simulations

    NASA Technical Reports Server (NTRS)

    Madden, Michael M.

    2007-01-01

    A vehicle simulation is surface-interacting if the state of the vehicle (position, velocity, and acceleration) relative to the surface is important. Surface-interacting simulations perform ascent, entry, descent, landing, surface travel, or atmospheric flight. Modeling of gravity is an influential environmental factor for surface-interacting simulations. Gravity is the free-fall acceleration observed from a world-fixed frame that rotates with the world. Thus, gravity is the sum of gravitation and the centrifugal acceleration due to the world s rotation. In surface-interacting simulations, the fidelity of gravity at heights above the surface is more significant than gravity fidelity at locations in inertial space. A surface-interacting simulation cannot treat the gravity model separately from the world model, which simulates the motion and shape of the world. The world model's simulation of the world's rotation, or lack thereof, produces the centrifugal acceleration component of gravity. The world model s reproduction of the world's shape will produce different positions relative to the world center for a given height above the surface. These differences produce variations in the gravitation component of gravity. This paper examines the actual performance of world and gravity/gravitation pairs in a simulation using the Earth.

  5. Environmental influences on maize-Aspergillus flavus interactions and aflatoxin production

    PubMed Central

    Fountain, Jake C.; Scully, Brian T.; Ni, Xinzhi; Kemerait, Robert C.; Lee, Robert D.; Chen, Zhi-Yuan; Guo, Baozhu

    2014-01-01

    Since the early 1960s, the fungal pathogen Aspergillus flavus (Link ex Fr.) has been the focus of intensive research due to the production of carcinogenic and highly toxic secondary metabolites collectively known as aflatoxins following pre-harvest colonization of crops. Given this recurrent problem and the occurrence of a severe aflatoxin outbreak in maize (Zea mays L.), particularly in the Southeast U.S. in the 1977 growing season, a significant research effort has been put forth to determine the nature of the interaction occurring between aflatoxin production, A. flavus, environment and its various hosts before harvest. Many studies have investigated this interaction at the genetic, transcript, and protein levels, and in terms of fungal biology at either pre- or post-harvest time points. Later experiments have indicated that the interaction and overall resistance phenotype of the host is a quantitative trait with a relatively low heritability. In addition, a high degree of environmental interaction has been noted, particularly with sources of abiotic stress for either the host or the fungus such as drought or heat stresses. Here, we review the history of research into this complex interaction and propose future directions for elucidating the relationship between resistance and susceptibility to A. flavus colonization, abiotic stress, and its relationship to oxidative stress in which aflatoxin production may function as a form of antioxidant protection to the producing fungus. PMID:24550905

  6. Inbreeding depression in an insect with maternal care: influences of family interactions, life stage and offspring sex.

    PubMed

    Meunier, J; Kölliker, M

    2013-10-01

    Although inbreeding is commonly known to depress individual fitness, the severity of inbreeding depression varies considerably across species. Among the factors contributing to this variation, family interactions, life stage and sex of offspring have been proposed, but their joint influence on inbreeding depression remains poorly understood. Here, we demonstrate that these three factors jointly shape inbreeding depression in the European earwig, Forficula auricularia. Using a series of cross-breeding, split-clutch and brood size manipulation experiments conducted over two generations, we first showed that sib mating (leading to inbred offspring) did not influence the reproductive success of earwig parents. Second, the presence of tending mothers and the strength of sibling competition (i.e. brood size) did not influence the expression of inbreeding depression in the inbred offspring. By contrast, our results revealed that inbreeding dramatically depressed the reproductive success of inbred adult male offspring, but only had little effect on the reproductive success of inbred adult female offspring. Overall, this study demonstrates limited effects of family interactions on inbreeding depression in this species and emphasizes the importance of disentangling effects of sib mating early and late during development to better understand the evolution of mating systems and population dynamics.

  7. Systematic mapping of genetic interaction networks.

    PubMed

    Dixon, Scott J; Costanzo, Michael; Baryshnikova, Anastasia; Andrews, Brenda; Boone, Charles

    2009-01-01

    Genetic interactions influencing a phenotype of interest can be identified systematically using libraries of genetic tools that perturb biological systems in a defined manner. Systematic screens conducted in the yeast Saccharomyces cerevisiae have identified thousands of genetic interactions and provided insight into the global structure of biological networks. Techniques enabling systematic genetic interaction mapping have been extended to other single-celled organisms, the bacteria Escherichia coli and the yeast Schizosaccharomyces pombe, opening the way to comparative investigations of interaction networks. Genetic interaction screens in Caenorhabditis elegans, Drosophila melanogaster, and mammalian models are helping to improve our understanding of metazoan-specific signaling pathways. Together, our emerging knowledge of the genetic wiring diagrams of eukaryotic and prokaryotic cells is providing a new understanding of the relationship between genotype and phenotype.

  8. Phase diagram of softly repulsive systems: the Gaussian and inverse-power-law potentials.

    PubMed

    Prestipino, Santi; Saija, Franz; Giaquinta, Paolo V

    2005-10-01

    We redraw, using state-of-the-art methods for free-energy calculations, the phase diagrams of two reference models for the liquid state: the Gaussian and inverse-power-law repulsive potentials. Notwithstanding the different behaviors of the two potentials for vanishing interparticle distances, their thermodynamic properties are similar in a range of densities and temperatures, being ruled by the competition between the body-centered-cubic (bcc) and face-centered-cubic (fcc) crystalline structures and the fluid phase. We confirm the existence of a reentrant bcc phase in the phase diagram of the Gaussian-core model, just above the triple point. We also trace the bcc-fcc coexistence line of the inverse-power-law model as a function of the power exponent n and relate the common features in the phase diagrams of such systems to the softness degree of the interaction. PMID:16238377

  9. The influence of arene-ring size on stacking interaction with canonical base pairs

    NASA Astrophysics Data System (ADS)

    Formánek, Martin; Burda, Jaroslav V.

    2014-04-01

    Stacking interactions between aromatic molecules (benzene, p-cymene, biphenyl, and di- and tetra-hydrogen anthracene) and G.C and A.T canonical Watson-Crick (WC) base pairs are explored. Two functionals with dispersion corrections: ω-B97XD and B3LYP-D3 are used. For a comparison also the MP2 and B3LYP-D3/PCM methods were used for the most stable p-cymene…WC geometries. It was found that the stacking interaction increases with the size of π-conjugation system. Its extent is in agreement with experimental finding on anticancer activity of Ru(II) piano-stool complexes where intercalation of these aromatic molecules should play an important role. The explored structures are considered as ternary system so that decomposition of the interaction energy to pairwise and non-additivity contributions is also examined.

  10. Influences of the size and hydroxyl number of fullerenes/fullerenols on their interactions with proteins.

    PubMed

    Wu, Xian; Yang, Sheng-Tao; Wang, Haifang; Wang, Luyao; Hu, Wenxiang; Cao, Aoneng; Liu, Yuanfang

    2010-10-01

    In this study, we systematically investigated the interaction of fullerenes/fullerenols with model proteins using a widely used computational docking program Autodock 4.0. We found that pi-pi interaction existed in all the proteins-fullerene/fullerenol systems investigated here, and contributed greatly to the overall interaction energy. We also found that with the increase of the carbon cage size, the binding strength between proteins and fullerenes/fullerenols increased constantly. In addition, our results show that functionalization of fullerenes with polar groups, such as hydroxyl groups, decreases the binding between proteins and fullerene derivatives. In other words, the more hydroxyl groups on fullerenols, the weaker binding between proteins and fullerenols.

  11. Building a responsive teacher: how temporal contingency of gaze interaction influences word learning with virtual tutors

    PubMed Central

    Lee, Hanju; Kanakogi, Yasuhiro; Hiraki, Kazuo

    2015-01-01

    Animated pedagogical agents are lifelike virtual characters designed to augment learning. A review of developmental psychology literature led to the hypothesis that the temporal contingency of such agents would promote human learning. We developed a Pedagogical Agent with Gaze Interaction (PAGI), an experimental animated pedagogical agent that engages in gaze interaction with students. In this study, university students learned words of a foreign language, with temporally contingent PAGI (live group) or recorded version of PAGI (recorded group), which played pre-recorded sequences from live sessions. The result revealed that students in the live group scored considerably better than those in the recorded group. The finding indicates that incorporating temporal contingency of gaze interaction from a pedagogical agent has positive effect on learning. PMID:26064584

  12. Influence of homology and node age on the growth of protein-protein interaction networks

    NASA Astrophysics Data System (ADS)

    Bottinelli, Arianna; Bassetti, Bruno; Lagomarsino, Marco Cosentino; Gherardi, Marco

    2012-10-01

    Proteins participating in a protein-protein interaction network can be grouped into homology classes following their common ancestry. Proteins added to the network correspond to genes added to the classes, so the dynamics of the two objects are intrinsically linked. Here we first introduce a statistical model describing the joint growth of the network and the partitioning of nodes into classes, which is studied through a combined mean-field and simulation approach. We then employ this unified framework to address the specific issue of the age dependence of protein interactions through the definition of three different node wiring or divergence schemes. A comparison with empirical data indicates that an age-dependent divergence move is necessary in order to reproduce the basic topological observables together with the age correlation between interacting nodes visible in empirical data. We also discuss the possibility of nontrivial joint partition and topology observables.

  13. Polyakov loop, diquarks, and the two-flavor phase diagram

    SciTech Connect

    Roessner, S.; Weise, W.; Ratti, C.

    2007-02-01

    An updated version of the PNJL model is used to study the thermodynamics of N{sub f}=2 quark flavors interacting through chiral four-point couplings and propagating in a homogeneous Polyakov loop background. Previous PNJL calculations are extended by introducing explicit diquark degrees of freedom and an improved effective potential for the Polyakov loop field. The mean field equations are treated under the aspect of accommodating group theoretical constraints and issues arising from the fermion sign problem. The input is fixed exclusively by selected pure-gauge lattice QCD results and by pion properties in vacuum. The resulting (T,{mu}) phase diagram is studied with special emphasis on the critical point, its dependence on the quark mass and on Polyakov loop dynamics. We present successful comparisons with lattice QCD thermodynamics expanded to finite chemical potential {mu}.

  14. Phase Diagram and Electronic Structure of Praseodymium and Plutonium

    NASA Astrophysics Data System (ADS)

    Lanatà, Nicola; Yao, Yongxin; Wang, Cai-Zhuang; Ho, Kai-Ming; Kotliar, Gabriel

    2015-01-01

    We develop a new implementation of the Gutzwiller approximation in combination with the local density approximation, which enables us to study complex 4 f and 5 f systems beyond the reach of previous approaches. We calculate from first principles the zero-temperature phase diagram and electronic structure of Pr and Pu, finding good agreement with the experiments. Our study of Pr indicates that its pressure-induced volume-collapse transition would not occur without change of lattice structure—contrarily to Ce. Our study of Pu shows that the most important effect originating the differentiation between the equilibrium densities of its allotropes is the competition between the Peierls effect and the Madelung interaction and not the dependence of the electron correlations on the lattice structure.

  15. Particle diagrams and embedded many-body random matrix theory.

    PubMed

    Small, R A; Müller, S

    2014-07-01

    We present a method which uses Feynman-like diagrams to calculate the statistical quantities of embedded many-body random matrix problems. The method provides a promising alternative to existing techniques and offers many important simplifications. We use it here to find the fourth, sixth, and eighth moments of the level density of an m-body system with k fermions or bosons interacting through a random Hermitian potential (k ≤ m) in the limit where the number of possible single-particle states is taken to infinity. All share the same transition, starting immediately after 2k = m, from moments arising from a semicircular level density to Gaussian moments. The results also reveal a striking feature; the domain of the 2nth moment is naturally divided into n subdomains specified by the points 2k = m,3 k = m,...,nk = m. PMID:25122235

  16. Intramembrane aromatic interactions influence the lipid sensitivities of pentameric ligand-gated ion channels.

    PubMed

    Carswell, Casey L; Sun, Jiayin; Baenziger, John E

    2015-01-23

    Although the Torpedo nicotinic acetylcholine receptor (nAChR) reconstituted into phosphatidylcholine (PC) membranes lacking cholesterol and anionic lipids adopts a conformation where agonist binding is uncoupled from channel gating, the underlying mechanism remains to be defined. Here, we examine the mechanism behind lipid-dependent uncoupling by comparing the propensities of two prokaryotic homologs, Gloebacter and Erwinia ligand-gated ion channel (GLIC and ELIC, respectively), to adopt a similar uncoupled conformation. Membrane-reconstituted GLIC and ELIC both exhibit folded structures in the minimal PC membranes that stabilize an uncoupled nAChR. GLIC, with a large number of aromatic interactions at the interface between the outermost transmembrane α-helix, M4, and the adjacent transmembrane α-helices, M1 and M3, retains the ability to flux cations in this uncoupling PC membrane environment. In contrast, ELIC, with a level of aromatic interactions intermediate between that of the nAChR and GLIC, does not undergo agonist-induced channel gating, although it does not exhibit the expected biophysical characteristics of the uncoupled state. Engineering new aromatic interactions at the M4-M1/M3 interface to promote effective M4 interactions with M1/M3, however, increases the stability of the transmembrane domain to restore channel function. Our data provide direct evidence that M4 interactions with M1/M3 are modulated during lipid sensing. Aromatic residues strengthen M4 interactions with M1/M3 to reduce the sensitivities of pentameric ligand-gated ion channels to their surrounding membrane environment. PMID:25519904

  17. The Mental Health Outcomes of Drought: A Systematic Review and Causal Process Diagram.

    PubMed

    Vins, Holly; Bell, Jesse; Saha, Shubhayu; Hess, Jeremy J

    2015-10-22

    Little is understood about the long term, indirect health consequences of drought (a period of abnormally dry weather). In particular, the implications of drought for mental health via pathways such as loss of livelihood, diminished social support, and rupture of place bonds have not been extensively studied, leaving a knowledge gap for practitioners and researchers alike. A systematic review of literature was performed to examine the mental health effects of drought. The systematic review results were synthesized to create a causal process diagram that illustrates the pathways linking drought effects to mental health outcomes. Eighty-two articles using a variety of methods in different contexts were gathered from the systematic review. The pathways in the causal process diagram with greatest support in the literature are those focusing on the economic and migratory effects of drought. The diagram highlights the complexity of the relationships between drought and mental health, including the multiple ways that factors can interact and lead to various outcomes. The systematic review and resulting causal process diagram can be used in both practice and theory, including prevention planning, public health programming, vulnerability and risk assessment, and research question guidance. The use of a causal process diagram provides a much needed avenue for integrating the findings of diverse research to further the understanding of the mental health implications of drought.

  18. The Mental Health Outcomes of Drought: A Systematic Review and Causal Process Diagram

    PubMed Central

    Vins, Holly; Bell, Jesse; Saha, Shubhayu; Hess, Jeremy J.

    2015-01-01

    Little is understood about the long term, indirect health consequences of drought (a period of abnormally dry weather). In particular, the implications of drought for mental health via pathways such as loss of livelihood, diminished social support, and rupture of place bonds have not been extensively studied, leaving a knowledge gap for practitioners and researchers alike. A systematic review of literature was performed to examine the mental health effects of drought. The systematic review results were synthesized to create a causal process diagram that illustrates the pathways linking drought effects to mental health outcomes. Eighty-two articles using a variety of methods in different contexts were gathered from the systematic review. The pathways in the causal process diagram with greatest support in the literature are those focusing on the economic and migratory effects of drought. The diagram highlights the complexity of the relationships between drought and mental health, including the multiple ways that factors can interact and lead to various outcomes. The systematic review and resulting causal process diagram can be used in both practice and theory, including prevention planning, public health programming, vulnerability and risk assessment, and research question guidance. The use of a causal process diagram provides a much needed avenue for integrating the findings of diverse research to further the understanding of the mental health implications of drought. PMID:26506367

  19. Language Interaction in Nahuatl Discourse: The Influence of Spanish in Child and Adult Narratives.

    ERIC Educational Resources Information Center

    Francis, Norbert; Gomez, Pablo Rogelio Navarrete

    2003-01-01

    This study on code-mixing focuses on the influence of Spanish in Nahuatl discourse as revealed in narratives produced by adults and children. Results indicate differences in frequency of content word embedded language (Spanish), lexical items across grade level (for children), grade level attained (for adults), and correlations (for children)…

  20. Influence of Sound Immersion and Communicative Interaction on the Lombard Effect

    ERIC Educational Resources Information Center

    Garnier, Maeva; Henrich, Nathalie; Dubois, Daniele

    2010-01-01

    Purpose: To examine the influence of sound immersion techniques and speech production tasks on speech adaptation in noise. Method: In Experiment 1, we compared the modification of speakers' perception and speech production in noise when noise is played into headphones (with and without additional self-monitoring feedback) or over loudspeakers. We…