Science.gov

Sample records for experience structured interactions

  1. C-SIDE: The control-structure interaction demonstration experiment

    NASA Technical Reports Server (NTRS)

    Mohl, James B.; Davis, Hugh W.

    1993-01-01

    The Control-Structure Interaction Demonstration Experiment (C-SIDE) is sponsored by the Electro-Optics and Cryogenics Division of Ball Aerospace Systems Group. Our objective is to demonstrate methods of solution to structure control problems utilizing currently available hardware in a system that is an extension of our corporate experience. The larger space structures with which Ball has been associated are the SEASAT radar antenna, Shuttle Imaging Radar (SIR) -A, -B and -C antennas and the Radarsat spacecraft. The motivation for the C-SIDE configuration is to show that integration of active figure control in the radar's system-level design can relieve antenna mechanical design constraints. This presentation is primarily an introduction to the C-SIDE testbed. Its physical and functional layouts, and major components are described. The sensor is of special interest as it enables direct surface figure measurements from a remote location. The Remote Attitude Measurement System (RAMS) makes high-rate, unobtrusive measurements of many locations, several of which may be collocated easily with actuators. The control processor is a 386/25 executing a reduced order model-based algorithm with provision for residual mode filters to compensate for structure interaction. The actuators for the ground demonstration are non-contacting, linear force devices. Results presented illustrate some basic characteristics of control-structure interaction with this hardware. The testbed will be used for evaluation of current technologies and for research in several areas. A brief indication of the evolution of the C-SIDE is given at the conclusion.

  2. Technically Speaking: On the Structure and Experience of Interaction Involving Augmentative Alternative Communications

    ERIC Educational Resources Information Center

    Engelke, Christopher Robert

    2013-01-01

    Technically Speaking: On the Structure and Experience of Interaction Involving Augmentative Alternative Communications examines the ways that communication is structured and experienced by looking at interactions involving augmented communicators--people with severe speech disabilities who use forms of assistive technology in order to communicate…

  3. Interaction of light with hematite hierarchical structures: Experiments and simulations

    NASA Astrophysics Data System (ADS)

    Distaso, Monica; Zhuromskyy, Oleksander; Seemann, Benjamin; Pflug, Lukas; Mačković, Mirza; Encina, Ezequiel; Taylor, Robin Klupp; Müller, Rolf; Leugering, Günter; Spiecker, Erdmann; Peschel, Ulf; Peukert, Wolfgang

    2017-03-01

    Mesocrystalline particles have been recognized as a class of multifunctional materials with potential applications in different fields. However, the internal organization of nanocomposite mesocrystals and its influence on the final properties have not yet been investigated. In this paper, a novel strategy based on electrodynamic simulations is developed to shed light on how the internal structure of mesocrystals influences their optical properties. In a first instance, a unified design protocol is reported for the fabrication of hematite/PVP particles with different morphologies such as pseudo-cubes, rods-like and apple-like structures and controlled particle size distributions. The optical properties of hematite/PVP mesocrystals are effectively simulated by taking their aggregate and nanocomposite structure into consideration. The superposition T-Matrix approach accounts for the aggregate nature of mesocrystalline particles and validate the effective medium approximation used in the framework of the Mie theory and electromagnetic simulation such as Finite Element Method. The approach described in our paper provides the framework to understand and predict the optical properties of mesocrystals and more general, of hierarchical nanostructured particles.

  4. Remote Manipulator System (RMS)-based Controls-Structures Interaction (CSI) flight experiment feasibility study

    NASA Technical Reports Server (NTRS)

    Demeo, Martha E.

    1990-01-01

    The feasibility of an experiment which will provide an on-orbit validation of Controls-Structures Interaction (CSI) technology, was investigated. The experiment will demonstrate the on-orbit characterization and flexible-body control of large flexible structure dynamics using the shuttle Remote Manipulator System (RMS) with an attached payload as a test article. By utilizing existing hardware as well as establishing integration, operation and safety algorithms, techniques and procedures, the experiment will minimize the costs and risks of implementing a flight experiment. The experiment will also offer spin-off enhancement to both the Shuttle RMS (SRMS) and the Space Station RMS (SSRMS).

  5. Spatial memories of virtual environments: how egocentric experience, intrinsic structure, and extrinsic structure interact.

    PubMed

    Kelly, Jonathan W; McNamara, Timothy P

    2008-04-01

    Previous research has uncovered three primary cues that influence spatial memory organization:egocentric experience, intrinsic structure (object defined), and extrinsic structure (environment defined). In the present experiments, we assessed the relative importance of these cues when all three were available during learning. Participants learned layouts from two perspectives in immersive virtual reality. In Experiment 1, axes defined by intrinsic and extrinsic structures were in conflict, and learning occurred from two perspectives, each aligned with either the intrinsic or the extrinsic structure. Spatial memories were organized around a reference direction selected from the first perspective, regardless of its alignment with intrinsic or extrinsic structures. In Experiment 2, axes defined by intrinsic and extrinsic structures were congruent, and spatial memories were organized around reference axes defined by those congruent structures, rather than by the initially experienced view. The findings are discussed in the context of spatial memory theory as it relates to real and virtual environments.

  6. Experiment for validation of fluid-structure interaction models and algorithms.

    PubMed

    Hessenthaler, A; Gaddum, N R; Holub, O; Sinkus, R; Röhrle, O; Nordsletten, D

    2016-11-04

    In this paper a fluid-structure interaction (FSI) experiment is presented. The aim of this experiment is to provide a challenging yet easy-to-setup FSI test case that addresses the need for rigorous testing of FSI algorithms and modeling frameworks. Steady-state and periodic steady-state test cases with constant and periodic inflow were established. Focus of the experiment is on biomedical engineering applications with flow being in the laminar regime with Reynolds numbers 1283 and 651. Flow and solid domains were defined using computer-aided design (CAD) tools. The experimental design aimed at providing a straightforward boundary condition definition. Material parameters and mechanical response of a moderately viscous Newtonian fluid and a nonlinear incompressible solid were experimentally determined. A comprehensive data set was acquired by using magnetic resonance imaging to record the interaction between the fluid and the solid, quantifying flow and solid motion.

  7. Nonlinear soil-structure interaction calculations simulating the SIMQUAKE experiment using STEALTH 2D

    NASA Technical Reports Server (NTRS)

    Tang, H. T.; Hofmann, R.; Yee, G.; Vaughan, D. K.

    1980-01-01

    Transient, nonlinear soil-structure interaction simulations of an Electric Power Research Institute, SIMQUAKE experiment were performed using the large strain, time domain STEALTH 2D code and a cyclic, kinematically hardening cap soil model. Results from the STEALTH simulations were compared to identical simulations performed with the TRANAL code and indicate relatively good agreement between all the STEALTH and TRANAL calculations. The differences that are seen can probably be attributed to: (1) large (STEALTH) vs. small (TRANAL) strain formulation and/or (2) grid discretization differences.

  8. Observations of flow path interactions with surface structures during initial soil development stage using irrigation experiments

    NASA Astrophysics Data System (ADS)

    Bartl, Steffen; Biemelt, Detlef; Badorreck, Annika; Gerke, Horst H.

    2010-05-01

    Structures and processes are dynamically linked especially during initial stages of soil and ecosystem development. Here we assume that soil pore structures and micro topography determine the flow paths and water fluxes as well as further structure changes. Reports about flow path developments at the soil surface are still limited because of an insufficient knowledge of the changing micro topography at the surface. The objective of this presentation is to evaluate methods for parameterisation of surface micro topography for analysing interactions between infiltration and surface runoff. Complex irrigation experiments were carried out at an experimental site in the neighbourhood of the artificially created water catchment "Chicken Creek". The irrigation rates between 160 mm/h and 250 mm/h were held constant over a time period of 20 minutes. The incoming intensities were measured as well as the raindrop-velocity and -size distributions. The surface runoff was continuously registered, soil samples were taken, and soil water potential heads were monitored using tensiometers. Surface and subsurface flow paths were identified using different tracers. The soil surface structures were recorded using a high resolution digital camera before, during, and after irrigation. Micro topography was surveyed using close-range photogrammetry. With this experimental design both, flow paths on the surface and in the soil as well as structure and texture changes could be observed simultaneously. In 2D vertical cross-sections, the effect of initial sediment deposition structure on infiltration and runoff was observed. Image analysis of surface pictures allowed identifying structural and soil textural changes during the runoff process. Similar structural changes related to surface flow paths were found with the photogrammetric surface analysis. We found evidence for the importance of the initial structures on the flow paths as well as a significant influence of the system development

  9. Peer Observed Interaction and Structured Evaluation (POISE): a Canadian experience with peer supervision for genetic counselors.

    PubMed

    Goldsmith, Claire; Honeywell, Christina; Mettler, Gabrielle

    2011-04-01

    Peer observation, while often used in other professions, has not been formally applied in genetic counseling. The objective of this study was to pilot a method of peer evaluation whereby genetic counselors observed, and were observed by, each other during patient interaction. All of the available genetic counselors participated in both rounds of the pilot study (six in round one, seven in round two). The genetic counselors that observed the session used an observation room. Most participants reported learning a new skill. Sensitivity to, and comfort with, the feedback process improved. We conclude that Peer-Observed Interaction and Structured Evaluation (POISE) provides an opportunity to refresh counseling approaches and develop feedback skills without causing undue team discord. This new approach to peer supervision in genetic counselling offers a live observation approach for genetic counsellor supervision.

  10. Modal interactions due to friction in the nonlinear vibration response of the "Harmony" test structure: Experiments and simulations

    NASA Astrophysics Data System (ADS)

    Claeys, M.; Sinou, J.-J.; Lambelin, J.-P.; Todeschini, R.

    2016-08-01

    The nonlinear vibration response of an assembly with friction joints - named "Harmony" - is studied both experimentally and numerically. The experimental results exhibit a softening effect and an increase of dissipation with excitation level. Modal interactions due to friction are also evidenced. The numerical methodology proposed groups together well-known structural dynamic methods, including finite elements, substructuring, Harmonic Balance and continuation methods. On the one hand, the application of this methodology proves its capacity to treat a complex system where several friction movements occur at the same time. On the other hand, the main contribution of this paper is the experimental and numerical study of evidence of modal interactions due to friction. The simulation methodology succeeds in reproducing complex form of dynamic behavior such as these modal interactions.

  11. Experiment in Structural Learning.

    ERIC Educational Resources Information Center

    Diener, Z. P.

    The concern of the experiment is to find out the roles of abstraction and generalization in the learning of mathematical structures. The basic question is whether to generalize before abstracting or vice-versa in order to maximize transfer. The experiment involves four mathematical tasks and a transfer of activity. Experimental procedures are…

  12. Interaction of curcumin with Al(III) and its complex structures based on experiments and theoretical calculations

    NASA Astrophysics Data System (ADS)

    Jiang, Teng; Wang, Long; Zhang, Sui; Sun, Ping-Chuan; Ding, Chuan-Fan; Chu, Yan-Qiu; Zhou, Ping

    2011-10-01

    Curcumin has been recognized as a potential natural drug to treat the Alzheimer's disease (AD) by chelating baleful metal ions, scavenging radicals and preventing the amyloid β (Aβ) peptides from the aggregation. In this paper, Al(III)-curcumin complexes with Al(III) were synthesized and characterized by liquid-state 1H, 13C and 27Al nuclear magnetic resonance (NMR), mass spectroscopy (MS), ultraviolet spectroscopy (UV) and generalized 2D UV-UV correlation spectroscopy. In addition, the density functional theory (DFT)-based UV and chemical shift calculations were also performed to view insight into the structures and properties of curcumin and its complexes. It was revealed that curcumin could interact strongly with Al(III) ion, and form three types of complexes under different molar ratios of [Al(III)]/[curcumin], which would restrain the interaction of Al(III) with the Aβ peptide, reducing the toxicity effect of Al(III) on the peptide.

  13. Methods to test the interactive effects of drought and plant invasion on ecosystem structure and function using complementary common garden and field experiments.

    PubMed

    Alba, Christina; NeSmith, Julienne E; Fahey, Catherine; Angelini, Christine; Flory, Stephen Luke

    2017-03-01

    Abiotic global change drivers affect ecosystem structure and function, but how they interact with biotic factors such as invasive plants is understudied. Such interactions may be additive, synergistic, or offsetting, and difficult to predict. We present methods to test the individual and interactive effects of drought and plant invasion on native ecosystems. We coupled a factorial common garden experiment containing resident communities exposed to drought (imposed with rainout shelters) and invasion with a field experiment where the invader was removed from sites spanning a natural soil moisture gradient. We detail treatments and their effects on abiotic conditions, including soil moisture, light, temperature, and humidity, which shape community and ecosystem responses. Ambient precipitation during the garden experiment exceeded historic norms despite severe drought in prior years. Soil moisture was 48% lower in drought than ambient plots, but the invader largely offset drought effects. Additionally, temperature and light were lower and humidity higher in invaded plots. Field sites spanned up to a 10-fold range in soil moisture and up to a 2.5-fold range in light availability. Invaded and resident vegetation did not differentially mediate soil moisture, unlike in the garden experiment. Herbicide effectively removed invaded and resident vegetation, with removal having site-specific effects on soil moisture and light availability. However, light was generally higher in invader-removal than control plots, whereas resident removal had less effect on light, similar to the garden experiment. Invasion mitigated a constellation of abiotic conditions associated with drought stress in the garden experiment. In the field, where other factors co-varied, these patterns did not emerge. Still, neither experiment suggested that drought and invasion will have synergistic negative effects on ecosystems, although invasion can limit light availability. Coupling factorial garden

  14. Fluid structure interaction

    NASA Astrophysics Data System (ADS)

    Komatsu, K.

    A few nonflow field problems are considered, taking into account mainly fluid-shell dynamic interaction and fluid-solid impact. Fluid-shell systems are used as models for sloshing and POGO (structure-propulsion coupling oscillation) in liquid rockets, floating lids of oil tanks, large tanks containing fluid, nuclear containment vessels, and head injury studies in biomechanics. The study of structure-water impact finds applications in the problems associated with water landings of reentry vehicles, water entry of torpedoes, and slamming of ships in heavy seas. At least three different methods can be used in handling wet structures. Attention is given to the method which treats fluid by boundary elements and structure by finite elements.

  15. Structural interaction with control systems

    NASA Technical Reports Server (NTRS)

    Noll, R. B.; Zvara, J.

    1971-01-01

    A monograph which assesses the state of the art of space vehicle design and development is presented. The monograph presents criteria and recommended practices for determining the structural data and a mathematical structural model of the vehicle needed for accurate prediction of structure and control-system interaction; for design to minimize undesirable interactions between the structure and the control system; and for determining techniques to achieve the maximum desirable interactions and associated structural design benefits. All space vehicles are treated, including launch vehicles, spacecraft, and entry vehicles. Important structural characteristics which affect the structural model used for structural and control-system interaction analysis are given.

  16. Structure enhancement methodology using theory and experiment: gas-phase molecular structures using a dynamic interaction between electron diffraction, molecular mechanics, and ab initio data.

    PubMed

    Kafka, Graeme R; Masters, Sarah L; Rankin, David W H

    2007-07-05

    A new method of incorporating ab initio theoretical data dynamically into the gas-phase electron diffraction (GED) refinement process has been developed to aid the structure determination of large, sterically crowded molecules. This process involves calculating a set of differences between parameters that define the positions of peripheral atoms (usually hydrogen), as determined using molecular mechanics (MM), and those which use ab initio methods. The peripheral-atom positions are then updated continually during the GED refinement process, using MM, and the returned positions are modified using this set of differences to account for the differences between ab initio and MM methods, before being scaled back to the average parameters used to define them, as refined from experimental data. This allows the molecule to adopt a completely asymmetric structure if required, without being constrained by the MM parametrization, whereas the calculations can be performed on a practical time scale. The molecular structures of tri-tert-butylphosphine oxide and tri-tert-butylphosphine imide have been re-examined using this new technique, which we call SEMTEX (Structure Enhancement Methodology using Theory and EXperiment).

  17. Structural Assembly Demonstration Experiment (SADE)

    NASA Technical Reports Server (NTRS)

    Akin, David L.; Mills, Raymond A.; Bowden, Mary L.

    1987-01-01

    The purpose of the Structural Assembly Demonstration Experiment (SADE) was to create a near-term Shuttle flight experiment focusing on the deployment and erection of structural truss elements. The activities of the MIT Space Systems Laboratory consist of three major areas: preparing and conducting neutral buoyancy simulation test series; producing a formal SADE Experiment plan; and studying the structural dynamics issues of the truss structure. Each of these areas is summarized.

  18. ISE structural dynamic experiments

    NASA Technical Reports Server (NTRS)

    Lock, Malcolm H.; Clark, S. Y.

    1988-01-01

    The topics are presented in viewgraph form and include the following: directed energy systems - vibration issue; Neutral Particle Beam Integrated Space Experiment (NPB-ISE) opportunity/study objective; vibration sources/study plan; NPB-ISE spacecraft configuration; baseline slew analysis and results; modal contributions; fundamental pitch mode; vibration reduction approaches; peak residual vibration; NPB-ISE spacecraft slew experiment; goodbye ISE - hello Zenith Star Program.

  19. Control-structure interaction

    NASA Technical Reports Server (NTRS)

    Cheng, Joseph K.; Ianculescu, George D.; Kenney, Charles S.; Laub, Alan J.; Ly, Jason H. Q.; Papadopoulos, Philip M.

    1992-01-01

    The feasibility of using conventional proportional-integral-derivative (PID) control and an alternative optimal control to perform the pointing and tracking functions of the Space Station solar dynamic power module is investigated. A very large state model of 6 rigid body modes and 272 flexible modes is used in conjunction with classical linear-quadratic-Gaussian (LQG) optimal control to produce a full-order controller that satisfies the requirements. The results are compared with a classically designed PID controller that was implemented for a much smaller (6 rigid body, 40 flexible modes) model. The conventional control design approach is shown to be very much influenced by the order reduction of the plant model, i.e., the number of retained elastic modes from the full-order model, suggesting that for a complex, large space structure, such as the Space Station Freedom solar dynamic module, application of conventional control system design methods may not be adequate. The use of LQG control is recommended, and method for solving the large matrix. Riccati equation that arises from the optimal formulation is provided.

  20. Interactive Screen Experiments with Single Photons

    ERIC Educational Resources Information Center

    Bronner, Patrick; Strunz, Andreas; Silberhorn, Christine; Meyn, Jan-Peter

    2009-01-01

    Single photons are used for fundamental quantum physics experiments as well as for applications. Originally being a topic of advance courses, such experiments are increasingly a subject of undergraduate courses. We provide interactive screen experiments (ISE) for supporting the work in a real laboratory, and for students who do not have access to…

  1. Structural verification for GAS experiments

    NASA Technical Reports Server (NTRS)

    Peden, Mark Daniel

    1992-01-01

    The purpose of this paper is to assist the Get Away Special (GAS) experimenter in conducting a thorough structural verification of its experiment structural configuration, thus expediting the structural review/approval process and the safety process in general. Material selection for structural subsystems will be covered with an emphasis on fasteners (GSFC fastener integrity requirements) and primary support structures (Stress Corrosion Cracking requirements and National Space Transportation System (NSTS) requirements). Different approaches to structural verifications (tests and analyses) will be outlined especially those stemming from lessons learned on load and fundamental frequency verification. In addition, fracture control will be covered for those payloads that utilize a door assembly or modify the containment provided by the standard GAS Experiment Mounting Plate (EMP). Structural hazard assessment and the preparation of structural hazard reports will be reviewed to form a summation of structural safety issues for inclusion in the safety data package.

  2. Rapid Method Development in Hydrophilic Interaction Liquid Chromatography for Pharmaceutical Analysis Using a Combination of Quantitative Structure-Retention Relationships and Design of Experiments.

    PubMed

    Taraji, Maryam; Haddad, Paul R; Amos, Ruth I J; Talebi, Mohammad; Szucs, Roman; Dolan, John W; Pohl, Chris A

    2017-02-07

    A design-of-experiment (DoE) model was developed, able to describe the retention times of a mixture of pharmaceutical compounds in hydrophilic interaction liquid chromatography (HILIC) under all possible combinations of acetonitrile content, salt concentration, and mobile-phase pH with R(2) > 0.95. Further, a quantitative structure-retention relationship (QSRR) model was developed to predict retention times for new analytes, based only on their chemical structures, with a root-mean-square error of prediction (RMSEP) as low as 0.81%. A compound classification based on the concept of similarity was applied prior to QSRR modeling. Finally, we utilized a combined QSRR-DoE approach to propose an optimal design space in a quality-by-design (QbD) workflow to facilitate the HILIC method development. The mathematical QSRR-DoE model was shown to be highly predictive when applied to an independent test set of unseen compounds in unseen conditions with a RMSEP value of 5.83%. The QSRR-DoE computed retention time of pharmaceutical test analytes and subsequently calculated separation selectivity was used to optimize the chromatographic conditions for efficient separation of targets. A Monte Carlo simulation was performed to evaluate the risk of uncertainty in the model's prediction, and to define the design space where the desired quality criterion was met. Experimental realization of peak selectivity between targets under the selected optimal working conditions confirmed the theoretical predictions. These results demonstrate how discovery of optimal conditions for the separation of new analytes can be accelerated by the use of appropriate theoretical tools.

  3. Design for Engaging Experience and Social Interaction

    ERIC Educational Resources Information Center

    Harteveld, Casper; ten Thij, Eleonore; Copier, Marinka

    2011-01-01

    One of the goals of game designers is to design for an engaging experience and for social interaction. The question is how. We know that games can be engaging and allow for social interaction, but how do we achieve this or even improve on it? This article provides an overview of several scientific approaches that deal with this question. It…

  4. Organizational Learning from Cross-Cultural Experiences: An Ethnomethodological Case Study Examining the Relative Importance of Social Structure and Cultural Values during Dynamic Interaction

    ERIC Educational Resources Information Center

    Waldecker, Gary T.

    2011-01-01

    This study explored how social structure and cultural values dynamically interact in collective learning between two religious organizations cooperating in a joint project. It further explored the enablers of and impediments to collective learning in this context. The study employed the theoretical framework provided by the Organizational Learning…

  5. Localized structures in convective experiments

    NASA Astrophysics Data System (ADS)

    Burguete, J.; Mancini, H.

    2014-01-01

    In this work we review localized structures appearing in thermo-convective experiments performed in extended (large "aspect ratio") fluid layers. After a brief general review (not exhaustive), we focus on some results obtained in pure fluids in a Bénard-Marangoni system with non-homogeneous heating where some structures of this kind appear. The experimental results are compared in reference to the most classical observed in binary mixtures experiments or simulations. In the Bénard-Marangoni experiment we present the stability diagram where localized structures appear and the typical situations where these local mechanisms have been studied experimentally. Some new experimental results are also included. The authors want to honor Prof. H. Brand in his 60th. birthday and to thank him for helpful discussions.

  6. Acoustoelasticity. [sound-structure interaction

    NASA Technical Reports Server (NTRS)

    Dowell, E. H.

    1977-01-01

    Sound or pressure variations inside bounded enclosures are investigated. Mathematical models are given for determining: (1) the interaction between the sound pressure field and the flexible wall of a Helmholtz resonator; (2) coupled fluid-structural motion of an acoustic cavity with a flexible and/or absorbing wall; (3) acoustic natural modes in multiple connected cavities; and (4) the forced response of a cavity with a flexible and/or absorbing wall. Numerical results are discussed.

  7. Affective loop experiences: designing for interactional embodiment

    PubMed Central

    Höök, Kristina

    2009-01-01

    Involving our corporeal bodies in interaction can create strong affective experiences. Systems that both can be influenced by and influence users corporeally exhibit a use quality we name an affective loop experience. In an affective loop experience, (i) emotions are seen as processes, constructed in the interaction, starting from everyday bodily, cognitive or social experiences; (ii) the system responds in ways that pull the user into the interaction, touching upon end users' physical experiences; and (iii) throughout the interaction the user is an active, meaning-making individual choosing how to express themselves—the interpretation responsibility does not lie with the system. We have built several systems that attempt to create affective loop experiences with more or less successful results. For example, eMoto lets users send text messages between mobile phones, but in addition to text, the messages also have colourful and animated shapes in the background chosen through emotion-gestures with a sensor-enabled stylus pen. Affective Diary is a digital diary with which users can scribble their notes, but it also allows for bodily memorabilia to be recorded from body sensors mapping to users' movement and arousal and placed along a timeline. Users can see patterns in their bodily reactions and relate them to various events going on in their lives. The experiences of building and deploying these systems gave us insights into design requirements for addressing affective loop experiences, such as how to design for turn-taking between user and system, how to create for ‘open’ surfaces in the design that can carry users' own meaning-making processes, how to combine modalities to create for a ‘unity’ of expression, and the importance of mirroring user experience in familiar ways that touch upon their everyday social and corporeal experiences. But a more important lesson gained from deploying the systems is how emotion processes are co-constructed and

  8. Affective loop experiences: designing for interactional embodiment.

    PubMed

    Höök, Kristina

    2009-12-12

    Involving our corporeal bodies in interaction can create strong affective experiences. Systems that both can be influenced by and influence users corporeally exhibit a use quality we name an affective loop experience. In an affective loop experience, (i) emotions are seen as processes, constructed in the interaction, starting from everyday bodily, cognitive or social experiences; (ii) the system responds in ways that pull the user into the interaction, touching upon end users' physical experiences; and (iii) throughout the interaction the user is an active, meaning-making individual choosing how to express themselves-the interpretation responsibility does not lie with the system. We have built several systems that attempt to create affective loop experiences with more or less successful results. For example, eMoto lets users send text messages between mobile phones, but in addition to text, the messages also have colourful and animated shapes in the background chosen through emotion-gestures with a sensor-enabled stylus pen. Affective Diary is a digital diary with which users can scribble their notes, but it also allows for bodily memorabilia to be recorded from body sensors mapping to users' movement and arousal and placed along a timeline. Users can see patterns in their bodily reactions and relate them to various events going on in their lives. The experiences of building and deploying these systems gave us insights into design requirements for addressing affective loop experiences, such as how to design for turn-taking between user and system, how to create for 'open' surfaces in the design that can carry users' own meaning-making processes, how to combine modalities to create for a 'unity' of expression, and the importance of mirroring user experience in familiar ways that touch upon their everyday social and corporeal experiences. But a more important lesson gained from deploying the systems is how emotion processes are co-constructed and experienced

  9. Structure and interactions of biological helices

    NASA Astrophysics Data System (ADS)

    Kornyshev, Alexei A.; Lee, Dominic J.; Leikin, Sergey; Wynveen, Aaron

    2007-07-01

    Helices are essential building blocks of living organisms, be they molecular fragments of proteins ( α -helices), macromolecules (DNA and collagen), or multimolecular assemblies (microtubules and viruses). Their interactions are involved in packing of meters of genetic material within cells and phage heads, recognition of homologous genes in recombination and DNA repair, stability of tissues, and many other processes. Helical molecules form a variety of mesophases in vivo and in vitro. Recent structural studies, direct measurements of intermolecular forces, single-molecule manipulations, and other experiments have accumulated a wealth of information and revealed many puzzling physical phenomena. It is becoming increasingly clear that in many cases the physics of biological helices cannot be described by theories that treat them as simple, unstructured polyelectrolytes. The present article focuses on the most important and interesting aspects of the physics of structured macromolecules, highlighting various manifestations of the helical motif in their structure, elasticity, interactions with counterions, aggregation, and poly- and mesomorphic transitions.

  10. An experiment with interactive planning models

    NASA Technical Reports Server (NTRS)

    Beville, J.; Wagner, J. H.; Zannetos, Z. S.

    1970-01-01

    Experiments on decision making in planning problems are described. Executives were tested in dealing with capital investments and competitive pricing decisions under conditions of uncertainty. A software package, the interactive risk analysis model system, was developed, and two controlled experiments were conducted. It is concluded that planning models can aid management, and predicted uses of the models are as a central tool, as an educational tool, to improve consistency in decision making, to improve communications, and as a tool for consensus decision making.

  11. Interaction between Syntactic Structure and Information Structure in the Processing of a Head-Final Language

    ERIC Educational Resources Information Center

    Koizumi, Masatoshi; Imamura, Satoshi

    2017-01-01

    The effects of syntactic and information structures on sentence processing load were investigated using two reading comprehension experiments in Japanese, a head-final SOV language. In the first experiment, we discovered the main effects of syntactic and information structures, as well as their interaction, showing that interaction of these two…

  12. NASA/DOD Controls-Structures Interaction Technology 1989

    NASA Technical Reports Server (NTRS)

    Newsom, Jerry R. (Compiler)

    1989-01-01

    The purpose of this conference was to report to industry, academia, and government agencies on the current status of controls-structures interaction technology. The agenda covered ground testing, integrated design, analysis, flight experiments, and concepts.

  13. Control/structure interaction design methodology

    NASA Technical Reports Server (NTRS)

    Briggs, Hugh C.; Layman, William E.

    1989-01-01

    The Control Structure Interaction Program is a technology development program for spacecraft that exhibit interactions between the control system and structural dynamics. The program objectives include development and verification of new design concepts (such as active structure) and new tools (such as a combined structure and control optimization algorithm) and their verification in ground and possibly flight test. The new CSI design methodology is centered around interdisciplinary engineers using new tools that closely integrate structures and controls. Verification is an important CSI theme and analysts will be closely integrated to the CSI Test Bed laboratory. Components, concepts, tools and algorithms will be developed and tested in the lab and in future Shuttle-based flight experiments. The design methodology is summarized in block diagrams depicting the evolution of a spacecraft design and descriptions of analytical capabilities used in the process. The multiyear JPL CSI implementation plan is described along with the essentials of several new tools. A distributed network of computation servers and workstations was designed that will provide a state-of-the-art development base for the CSI technologies.

  14. Structural Dynamics and Control Interaction of Flexible Structures

    NASA Technical Reports Server (NTRS)

    Ryan, Robert S. (Editor); Scofield, Harold N. (Editor)

    1987-01-01

    A workshop on structural dynamics and control interaction of flexible structures was held to promote technical exchange between the structural dynamics and control disciplines, foster joint technology, and provide a forum for discussing and focusing critical issues in the separate and combined areas. Issues and areas of emphasis were identified in structure-control interaction for the next generation of flexible systems.

  15. Excitonic energy level structure and pigment-protein interactions in the recombinant water-soluble chlorophyll protein. II. Spectral hole-burning experiments.

    PubMed

    Pieper, J; Rätsep, M; Trostmann, I; Schmitt, F-J; Theiss, C; Paulsen, H; Eichler, H J; Freiberg, A; Renger, G

    2011-04-14

    Persistent spectral hole burning at 4.5 K has been used to investigate the excitonic energy level structure and the excited state dynamics of the recombinant class-IIa water-soluble chlorophyll-binding protein (WSCP) from cauliflower. The hole-burned spectra are composed of four main features: (i) a narrow zero-phonon hole (ZPH) at the burn wavelength, (ii) a number of vibrational ZPHs, (iii) a broad low-energy hole at ~665 and ~683 nm for chlorophyll b- and chlorophyll a-WSCP, respectively, and (iv) a second satellite hole at ~658 and ~673 nm for chlorophyll b- and chlorophyll a-WSCP, respectively. The doublet of broad satellite holes is assigned to an excitonically coupled chlorophyll dimer. The lower-energy holes at ~665 and ~683 nm for chlorophyll b- and chlorophyll a-WSCP, respectively, represent the lower exciton states. Taking into account the parameters of electron-phonon coupling, the lower exciton state can be assigned as the fluorescence origin. The lower exciton state is populated by two processes: (i) exciton relaxation from the higher exciton state and (ii) vibrational relaxation within the lower exciton state. Assuming identical site energies for the two excitonically coupled chlorophyll molecules, the dipole-dipole interaction energy J is directly determined to be 85 and 100 cm(-1) for chlorophyll b- and chlorophyll a-WSCP, respectively, based on the positions of the satellite holes. The Gaussian low-energy absorption band identified by constant fluence hole burning at 4.5 K has a width of ~150 cm(-1) and peaks at 664.9 and 682.7 nm for chlorophyll b- and chlorophyll a-WSCP, respectively. The action spectrum is broader and blue-shifted compared to the fluorescent lower exciton state. This finding can be explained by a slow protein relaxation between energetically inequivalent conformational substates within the lowest exciton state in agreement with the results of Schmitt et al. (J. Phys. Chem. B2008, 112, 13951).

  16. Interactive computer code for dynamic and soil structure interaction analysis

    SciTech Connect

    Mulliken, J.S.

    1995-12-01

    A new interactive computer code is presented in this paper for dynamic and soil-structure interaction (SSI) analyses. The computer program FETA (Finite Element Transient Analysis) is a self contained interactive graphics environment for IBM-PC`s that is used for the development of structural and soil models as well as post-processing dynamic analysis output. Full 3-D isometric views of the soil-structure system, animation of displacements, frequency and time domain responses at nodes, and response spectra are all graphically available simply by pointing and clicking with a mouse. FETA`s finite element solver performs 2-D and 3-D frequency and time domain soil-structure interaction analyses. The solver can be directly accessed from the graphical interface on a PC, or run on a number of other computer platforms.

  17. Transient cavitation in fluid-structure interactions

    SciTech Connect

    Kot, C.A.; Hsieh, B.J.; Youngdahl, C.K.; Valentin, R.A.

    1981-11-01

    A generalized column separation model is extended to predict transient cavitation associated with fluid-structure interactions. The essential feature of the combined fluid-structure interaction calculations is the coupling between the fluid transient, which is computed one dimensionally, and the structural response which can be multidimensional. Proper coupling is achieved by defining an average, one-dimensional, structural velocity and by assuming a spatially uniform pressure loading of the structure. This procedure is found to be effective even for complex finite element structural models for which the required computational time step is orders of magnitude smaller than that for the fluid transient. Computational examples and comparison with experimental data show that neglecting cavitation and setting the fluid velocity at all times equal to that of the structural boundary leads to unreal negative pressure predictions. A properly coupled column separation model reproduces the important features of fluid-structure interactions, converges rapidly, and gives reasonable fluid and structural response predictions. 9 refs.

  18. Ice interaction with offshore structures

    SciTech Connect

    Cammaert, A.B.; Muggeridge, D.B.

    1988-01-01

    Oil platforms and other offshore structures being built in the arctic regions must be able to withstand icebergs, ice islands, and pack ice. This reference explain the effect ice has on offshore structures and demonstrates design and construction methods that allow such structures to survive in harsh, ice-ridden environments. It analyzes the characteristics of sea ice as well as dynamic ice forces on structures. Techniques for ice modeling and field testing facilitate the design and construction of sturdy, offshore constructions. Computer programs included.

  19. Interactive Raster Data Structure Study.

    DTIC Science & Technology

    1983-01-01

    4-23 4-9 Basic Concepts of Conventional Relational Structures and Relational Algebra Operations. . .............. 4-24 4-10 Structural...Graphics-Oriented Relational Algebraic Interpreter Systems... ... ......... .. 4-33 4-15 Logical Picture Representation by Relational Tablets...attempts required users familiar with lineal -based features to conceive of cartographic * entities as scan lines and pixels of data. The relative maturity

  20. An Interactive Introduction to Protein Structure

    ERIC Educational Resources Information Center

    Lee, W. Theodore

    2004-01-01

    To improve student understanding of protein structure and the significance of noncovalent interactions in protein structure and function, students are assigned a project to write a paper complemented with computer-generated images. The assignment provides an opportunity for students to select a protein structure that is of interest and detail…

  1. Combustion: Structural interaction in a viscoelastic material

    NASA Technical Reports Server (NTRS)

    Chang, T. Y.; Chang, J. P.; Kumar, M.; Kuo, K. K.

    1980-01-01

    The effect of interaction between combustion processes and structural deformation of solid propellant was considered. The combustion analysis was performed on the basis of deformed crack geometry, which was determined from the structural analysis. On the other hand, input data for the structural analysis, such as pressure distribution along the crack boundary and ablation velocity of the crack, were determined from the combustion analysis. The interaction analysis was conducted by combining two computer codes, a combustion analysis code and a general purpose finite element structural analysis code.

  2. PSAIA – Protein Structure and Interaction Analyzer

    PubMed Central

    Mihel, Josip; Šikić, Mile; Tomić, Sanja; Jeren, Branko; Vlahoviček, Kristian

    2008-01-01

    Background PSAIA (Protein Structure and Interaction Analyzer) was developed to compute geometric parameters for large sets of protein structures in order to predict and investigate protein-protein interaction sites. Results In addition to most relevant established algorithms, PSAIA offers a new method PIADA (Protein Interaction Atom Distance Algorithm) for the determination of residue interaction pairs. We found that PIADA produced more satisfactory results than comparable algorithms implemented in PSAIA. Particular advantages of PSAIA include its capacity to combine different methods to detect the locations and types of interactions between residues and its ability, without any further automation steps, to handle large numbers of protein structures and complexes. Generally, the integration of a variety of methods enables PSAIA to offer easier automation of analysis and greater reliability of results. PSAIA can be used either via a graphical user interface or from the command-line. Results are generated in either tabular or XML format. Conclusion In a straightforward fashion and for large sets of protein structures, PSAIA enables the calculation of protein geometric parameters and the determination of location and type for protein-protein interaction sites. XML formatted output enables easy conversion of results to various formats suitable for statistic analysis. Results from smaller data sets demonstrated the influence of geometry on protein interaction sites. Comprehensive analysis of properties of large data sets lead to new information useful in the prediction of protein-protein interaction sites. PMID:18400099

  3. System Identification Tools for Control Structure Interaction

    DTIC Science & Technology

    1990-01-01

    DT! FILE COPY AL-TR-89-054 AD: 00 Final Report System Identification Tools for O for the period - September 1988 to Control Structure Interaction May...Classification) System Identification Tools for Control Structure Interaction (U) 12. PERSONAL AUTHOR(S) Kosut, Robert L.; Kabuli, Guntekin M. 13a. TYPE OF...identification, dynamics, 22 01 system identification , robustness, dynamic modeling, robust 22 02 control design, control design procedure 19. ABSTRACT

  4. Some Experiments in Atomic Structure

    ERIC Educational Resources Information Center

    Logan, Kent R.

    1974-01-01

    The role of spectral color slides in laboratory situations is discussed, then experiments for secondary school students concerning color and wave length, evidence of quantization, and the ionization energy of the hydrogen atom are outlined. Teaching guidelines for creating a set of spectrograms and photographic specifications are provided. (DT)

  5. Joint Optics Structures Experiment (JOSE)

    NASA Astrophysics Data System (ADS)

    Founds, David

    1987-06-01

    The objectives of the JOSE program is to develop, demonstrate, and evaluate active vibration suppression techniques for Directed Energy Weapons (DEW). DEW system performance is highly influenced by the line-of-sight (LOS) stability and in some cases by the wave front quality. The missions envisioned for DEW systems by the Strategic Defense Initiative require LOS stability and wave front quality to be significantly improved over any current demonstrated capability. The Active Control of Space Structures (ACOSS) program led to the development of a number of promising structural control techniques. DEW structures are vastly more complex than any structures controlled to date. They will be subject to disturbances with significantly higher magnitudes and wider bandwidths, while holding higher tolerances on allowable motions and deformations. Meeting the performance requirements of the JOSE program requires upgrading the ACOSS techniques to meet new more stringent requirements, the development of requisite sensors and acturators, improved control processors, highly accurate system identification methods, and the integration of hardware and methodologies into a successful demonstration.

  6. Joint Optics Structures Experiment (JOSE)

    NASA Technical Reports Server (NTRS)

    Founds, David

    1987-01-01

    The objectives of the JOSE program is to develop, demonstrate, and evaluate active vibration suppression techniques for Directed Energy Weapons (DEW). DEW system performance is highly influenced by the line-of-sight (LOS) stability and in some cases by the wave front quality. The missions envisioned for DEW systems by the Strategic Defense Initiative require LOS stability and wave front quality to be significantly improved over any current demonstrated capability. The Active Control of Space Structures (ACOSS) program led to the development of a number of promising structural control techniques. DEW structures are vastly more complex than any structures controlled to date. They will be subject to disturbances with significantly higher magnitudes and wider bandwidths, while holding higher tolerances on allowable motions and deformations. Meeting the performance requirements of the JOSE program requires upgrading the ACOSS techniques to meet new more stringent requirements, the development of requisite sensors and acturators, improved control processors, highly accurate system identification methods, and the integration of hardware and methodologies into a successful demonstration.

  7. Generalized Structured Component Analysis with Latent Interactions

    ERIC Educational Resources Information Center

    Hwang, Heungsun; Ho, Moon-Ho Ringo; Lee, Jonathan

    2010-01-01

    Generalized structured component analysis (GSCA) is a component-based approach to structural equation modeling. In practice, researchers may often be interested in examining the interaction effects of latent variables. However, GSCA has been geared only for the specification and testing of the main effects of variables. Thus, an extension of GSCA…

  8. Characterizing nanoparticle interactions: Linking models to experiments

    SciTech Connect

    Ramakrishnan, S.; Zukoski, C. F.

    2000-07-15

    Self-assembly of nanoparticles involves manipulating particle interactions such that attractions are on the order of the average thermal energy in the system. If the self-assembly is to result in an ordered packing, an understanding of their phase behavior is necessary. Here we test the ability of simple pair potentials to characterize the interactions and phase behavior of silico tungstic acid (STA), a 1.2 nm particle. The strength of interaction is controlled by dispersing STA in different background salt concentrations. The experimental variables used in characterizing the interactions are the osmotic compressibility (d{pi}/d{rho}), the second virial coefficient (B{sub 2}), relative solution viscosity ({eta}/{eta}{sub c}), and the solubility ({rho}{sigma}{sup 3}){sub sat}. Various techniques are then developed to extract the parameters of square well, the adhesive hard sphere (AHS), and the Yukawa pair potentials that best describe the experimental data. The AHS model describes the solution thermodynamic behavior only where the system is weakly attractive but, as would be expected, fails when long range repulsions or nonmonotonic pair potentials become important. Model free representations are presented which offer the opportunity to extract pair potential parameters. (c) 2000 American Institute of Physics.

  9. Working Smart Workbook. An Interactive Learning Experience.

    ERIC Educational Resources Information Center

    Los Angeles Unified School District, CA. Div. of Adult and Occupational Education.

    This workbook accompanies an interactive videodisc used in the Working Smart workplace literacy project prepared for the hotel and food services industry in the Los Angeles, California area. The first instructional unit addresses preparing the work area, including stocking supplies and cleaning the work area. The second instructional unit covers…

  10. Regularity of nuclear structure under random interactions

    SciTech Connect

    Zhao, Y. M.

    2011-05-06

    In this contribution I present a brief introduction to simplicity out of complexity in nuclear structure, specifically, the regularity of nuclear structure under random interactions. I exemplify such simplicity by two examples: spin-zero ground state dominance and positive parity ground state dominance in even-even nuclei. Then I discuss two recent results of nuclear structure in the presence of random interactions, in collaboration with Prof. Arima. Firstly I discuss sd bosons under random interactions, with the focus on excited states in the yrast band. We find a few regular patterns in these excited levels. Secondly I discuss our recent efforts towards obtaining eigenvalues without diagonalizing the full matrices of the nuclear shell model Hamiltonian.

  11. Intermolecular potentials from shock structure experiments. [for monatomic gases

    NASA Technical Reports Server (NTRS)

    Sturtevant, B.; Steinhilper, E. A.

    1974-01-01

    Ground-state intermolecular interaction potentials determined from shock structure experiments with four monatomic gases are reported. These potentials are assessed for self-consistency, using the law of corresponding states, and their suitability for engineering applications in rarefied gas dynamics is discussed.

  12. Liner target interaction experiments on Pegasus II

    SciTech Connect

    Hockaday, M.P.; Chrien, R.E.; Bartsch, R.

    1995-09-01

    The Los Alamos High Energy Density Physics program uses capacitively driven low voltage, inductive-storage pulse power to implode cylindrical targets for hydrodynamics experiments. Once a precision driver liner was characterized an experimental series characterizing the aluminum target dynamics was performed. The target was developed for shock-induced quasi-particle ejecta experiments including holography. The concept for the Liner shock experiment is that the driver liner is used to impact the target liner which then accelerates toward a collimator with a slit in it. A shock wave is set up in the target liner and as the shock emerges from the back side of the target liner, ejecta are generated. By taking a laser hologram the particle distribution of the ejecta are hoped to be determined. The goal for the second experimental series was to characterize the target dynamics and not to measure and generate the ejecta. Only the results from the third shot, Pegasus II-26 fired April 26th, 1994, from the series is discussed in detail. The second experimental series successfully characterized the target dynamics necessary to move forward towards the planned quasi-ejecta experiments.

  13. Interaction Between Air Propellers and Airplane Structures

    NASA Technical Reports Server (NTRS)

    Durand, W F

    1927-01-01

    The purpose of this investigation was the determination of the character and amount of interaction between air propellers as usually mounted on airplanes and the adjacent parts of the airplane structure - or, more specifically, those parts of the airplane structure within the wash of the propeller, and capable of producing any significant effect on propeller performance. In report no. 177 such interaction between air propellers and certain simple geometrical forms was made the subject of investigation and report. The present investigation aims to carry this general study one stage further by substituting actual airplane structures for the simple geometrical forms. From the point of view of the present investigation, the airplane structures, viewed as an obstruction in the wake of the propeller, must also be viewed as a necessary part of the airplane and not as an appendage which might be installed or removed at will. (author)

  14. RANS Modeling of Benchmark Shockwave / Boundary Layer Interaction Experiments

    NASA Technical Reports Server (NTRS)

    Georgiadis, Nick; Vyas, Manan; Yoder, Dennis

    2010-01-01

    This presentation summarizes the computations of a set of shock wave / turbulent boundary layer interaction (SWTBLI) test cases using the Wind-US code, as part of the 2010 American Institute of Aeronautics and Astronautics (AIAA) shock / boundary layer interaction workshop. The experiments involve supersonic flows in wind tunnels with a shock generator that directs an oblique shock wave toward the boundary layer along one of the walls of the wind tunnel. The Wind-US calculations utilized structured grid computations performed in Reynolds-averaged Navier-Stokes mode. Three turbulence models were investigated: the Spalart-Allmaras one-equation model, the Menter Shear Stress Transport wavenumber-angular frequency two-equation model, and an explicit algebraic stress wavenumber-angular frequency formulation. Effects of grid resolution and upwinding scheme were also considered. The results from the CFD calculations are compared to particle image velocimetry (PIV) data from the experiments. As expected, turbulence model effects dominated the accuracy of the solutions with upwinding scheme selection indicating minimal effects.!

  15. THz Radiation Generation via Laser Plasma Interaction Experiments

    NASA Astrophysics Data System (ADS)

    Yugami, Noboru; Higashiguchi, Takeshi

    2008-12-01

    Recently radiation generation from the interaction between laser and plasma is studied. Terahertz radiation from photo-conductive antenna which is based on semiconductor technology is widely used, The power is in the order of nano-watt level so that it is hard to use for application. On the other hand, terahertz radiation from laser plasma interaction is much higher than that of semiconductor technology. In our experiments, we have studied by use DARC (dc to ac radiation converter) mechanism by using YAG laser with nano-second pulse duration. DARC is novel radiation source using the interaction between laser-created ionization front and static electric field. The frequency of radiation is determined by both plasma density of ionization front and the geometry of DARC structure. We observed radiation pulse of frequency of 1.2 THz and pulse duration of 2 ps with ZnSe crystal as media detected by EO (electro-optics) sampling technique. Note from Publisher: This article contains the abstract only.

  16. Coulomb Interactions in Hanbury Brown-Twiss Experiments with Electrons

    ERIC Educational Resources Information Center

    Shen, Kan

    2009-01-01

    This dissertation examines the effect of Coulomb interactions in Hanbury Brown-Twiss (HBT) type experiments with electrons. HBT experiments deal with intensity interference, which is related to the second-order correlation function of the particle field. This is an extension of the usual amplitude interference experiment, such as Young's…

  17. Laser Mode Structure Experiments for Undergraduate Laboratories.

    ERIC Educational Resources Information Center

    Phillips, Richard A.; Gehrz, Robert D.

    Experiments dealing with laser mode structure are presented which are suitable for an upper division undergraduate laboratory. The theory of cavity modes is summarized. The mode structure of the radiation from a helium-neon laser is measured by using a photodiode detector and spectrum analyzer to detect intermode beating. Off-axial modes can be…

  18. Fundamental Structure of Matter and Strong Interaction

    SciTech Connect

    Jian-Ping Chen

    2011-11-01

    More than 99% of the visible matter in the universe are the protons and neutrons. Their internal structure is mostly governed by the strong interaction. Understanding their internal structure in terms of fundamental degrees-of-freedom is one of the most important subjects in modern physics. Worldwide efforts in the last few decades have lead to numerous surprises and discoveries, but major challenges still remain. An overview of the progress will be presented with a focus on the recent studies of the proton and neutron's electromagnetic and spin structure. Future perspectives will be discussed.

  19. On some structure-turbulence interaction problems

    NASA Technical Reports Server (NTRS)

    Maekawa, S.; Lin, Y. K.

    1976-01-01

    The interactions between a turbulent flow structure; responding to its excitation were studied. The turbulence was typical of those associated with a boundary layer, having a cross-spectral density indicative of convection and statistical decay. A number of structural models were considered. Among the one-dimensional models were an unsupported infinite beam and a periodically supported infinite beam. The fuselage construction of an aircraft was then considered. For the two-dimensional case a simple membrane was used to illustrate the type of formulation applicable to most two-dimensional structures. Both the one-dimensional and two-dimensional structures studied were backed by a cavity filled with an initially quiescent fluid to simulate the acoustic environment when the structure forms one side of a cabin of a sea vessel or aircraft.

  20. HAARP High Power Experiments and Observations of Ionospheric Interactions

    DTIC Science & Technology

    1996-01-01

    HAARP HIGH POWER EXPERIMENTS AND OBSERVATIONS OF IONOSPHERIC INTERACTIONS Paul Rodriguez(1), Edward Kennedy(2), Paul Kossey(3), Michael Kaiser(4...Initial experiments showed scintillation-like variations in low frequency propagation through the earth’s ionosphere . A HAARP -HIPAS transmission experiment... ionospheric irregularities. Recently, lunar echoes at 8 MHz were detected by WIND. The experiments at HAARP will extend to nonlinear regimes as power

  1. Microscopic Approaches to Nuclear Structure: Configuration Interaction

    SciTech Connect

    Ormand, W E

    2007-09-21

    The configuration interaction (CI) approach to solving the nuclear many-body problem, also known as the interacting shell model, has proven to be powerful tool in understanding the structure of nuclei. The principal criticism of past applications of the shell model is the reliance on empirical tuning to interaction matrix elements. If an accurate description of nuclei far from the valley of stability, where little or no data is available, a more fundamental approach is needed. This starts with recent ab initio approaches with effective interactions in the no-core shell model (NCSM). Using effective-field theory for guidance, fully ab initio descriptions of nuclei up to {sup 16}O with QCD based NN, NNN, and NNNN interactions will be possible within the next five years. An important task is then to determine how to use these NCSM results to develop effective interactions to describe heavier nuclei without the need to resort to an empirical retuning with every model space. Thus, it is likely that more traditional CI applications utilizing direct diagonalization and more fundamental interactions will be applicable to nuclei with perhaps up to one hundred constituents. But, these direct diagonalization CI applications will always be computationally limited due to the rapid increase in the number of configurations with particle number. Very recently, the shifted-contour method has been applied to the Auxiliary-field Monte Carlo approach to the Shell Model (AFMCSM), and preliminary applications exhibit a remarkable taming of the notorious sign problem. If the mitigation of the sign problem holds true, the AFMCSM will offer a method to compute quantum correlations to mean-field applications for just about all nuclei; giving exact results for CI model spaces that can approach 10{sup 20-25}. In these lectures, I will discuss modern applications of CI to the nuclear many-body problem that have the potential to guide nuclear structure theory into the next decade.

  2. Numerical analysis of soil-structure interaction

    NASA Astrophysics Data System (ADS)

    Vanlangen, Harry

    1991-05-01

    A study to improve some existing procedures for the finite element analysis of soil deformation and collapse is presented. Special attention is paid to problems of soil structure interaction. Emphasis is put on the behavior of soil rather than on that of structures. This seems to be justifiable if static interaction of stiff structures and soft soil is considered. In such a case nonlinear response will exclusively stem from soil deformation. In addition, the quality of the results depends to a high extent on the proper modeling of soil flow along structures and not on the modeling of the structure itself. An exception is made when geotextile reinforcement is considered. In that case the structural element, i.e., the geotextile, is highly flexible. The equation of continuum equilibrium, which serves as a starting point for the finite element formulation of large deformation elastoplasticity, is discussed with special attention being paid to the interpretation of some objective stress rate tensors. The solution of nonlinear finite element equations is addressed. Soil deformation in the prefailure range is discussed. Large deformation effect in the analysis of soil deformation is touched on.

  3. NASA SDO Social Media - An Interactive Experience

    NASA Astrophysics Data System (ADS)

    Durscher, R.; Wawro, M.; NASA SDO Social Media Team

    2011-12-01

    The world of social media has become an important outlet of information and news around the world. Social networking now accounts for over 25% of all time spent online in the US. NASA puts strong emphasis on its social media programs, and, in fact, is the top-ranked social media user in the public sector. We will describe our SDO Social Media project, which aims to engage the public in learning about the SDO mission, the Sun, space weather, and the impact the Sun has on Earth and other NASA exploration missions. We'll discuss the various social media outlets and the techniques we use for reaching and engaging our audience. Effectiveness is measured through the use of various automatically-gathered statistics and level of public engagement. Of key importance to effective social media use is having access to scientists who can quickly respond to questions and express their answers in meaningful ways to the public. Our presentation will highlight the importance of scientist involvement and suggest ways for encouraging more scientists to support these efforts. It will also address how our social media approach has been paving the way for other Mission E/PO teams in using our best practices and experiences.

  4. Joint Air Sea Interaction (JASIN) experiment, Northwest coast of Scotland

    NASA Technical Reports Server (NTRS)

    Businger, J. A.

    1981-01-01

    The joint air sea interaction (JASIN) experiment took place off the Northwest coast of Scotland. Sea surface and boundary layer parameters were measured. The JASIN data was used as ground truth for various sensors on the SEASAT satellite.

  5. Solvent-Ion Interactions in Salt Water: A Simple Experiment.

    ERIC Educational Resources Information Center

    Willey, Joan D.

    1984-01-01

    Describes a procedurally quick, simple, and inexpensive experiment which illustrates the magnitude and some effects of solvent-ion interactions in aqueous solutions. Theoretical information, procedures, and examples of temperature, volume and hydration number calculations are provided. (JN)

  6. Experiments In Characterizing Vibrations Of A Structure

    NASA Technical Reports Server (NTRS)

    Yam, Yeung; Hadaegh, Fred Y.; Bayard, David S.

    1993-01-01

    Report discusses experiments conducted to test methods of identification of vibrational and coupled rotational/vibrational modes of flexible structure. Report one in series that chronicle development of integrated system of methods, sensors, actuators, analog and digital signal-processing equipment, and algorithms to suppress vibrations in large, flexible structure even when dynamics of structure partly unknown and/or changing. Two prior articles describing aspects of research, "Autonomous Frequency-Domain Indentification" (NPO-18099), and "Automated Characterization Of Vibrations Of A Structure" (NPO-18141).

  7. Self-Structure and Emotional Experience

    PubMed Central

    Ditzfeld, Christopher P.; Showers, Carolin J.

    2013-01-01

    Two studies examine individual differences in affective reactivity by linking emotional experience to cognitive self-structure. Consistent with the view that individuals with an evaluatively compartmentalized self-structure are emotionally reactive, we find that evaluative compartmentalization is associated with the experience of, and desire for, high-arousal positive affect, whereas evaluative integration is associated with the experience of low-arousal positive and negative affect and the desire for low-arousal positive affect. Although compartmentalized individuals are less granular in their tendency to report experiencing both high- and low-arousal affect (cf. Feldman Barrett, 2004), they are strongly differentiated in their perceptions of high-arousal states as positive and low-arousal states as negative. Thus, compartmentalized individuals’ reactivity may be explained by their preference for high-arousal positive states and the “breadth” of their emotionality (e.g., the tendency to experience sadness and nervousness at the same time). PMID:24125479

  8. Fluid Structure Interaction Effect on Sandwich Composite Structures

    DTIC Science & Technology

    2011-09-01

    14. SUBJECT TERMS Fluid Structure Interaction, FSI, composite, balsa, low velocity impact, sandwich composites, VARTM , Vacuum Assisted Resin Transfer...11 1. Vacuum Assisted Resin Transfer Molding ( VARTM ) ...................11 2. Procedure...required equipment for VARTM composite production. ..............10 Figure 4. VARTM Lay-up (From [8

  9. Proton-neutron interaction and nuclear structure

    SciTech Connect

    Casten, R.F.

    1986-01-01

    The pervasive role of the proton-neutron interaction in nuclear structure is discussed. Particular emphasis is given to its influence on the onset of collectivity and deformation, on intruder states, and on the evolution of subshell structure. The N/sub p/N/sub n/ scheme is outlined and some applications of it to collective model calculations and to nuclei far off stability are described. The concept of N/sub p/N/sub n/ multiplets is introduced. 32 refs., 20 figs.

  10. Structural insights into microtubule doublet interactions inaxonemes

    SciTech Connect

    Downing, Kenneth H.; Sui, Haixin

    2007-06-06

    Coordinated sliding of microtubule doublets, driven by dynein motors, produces periodic beating of the axoneme. Recent structural studies of the axoneme have used cryo-electron tomography to reveal new details of the interactions among some of the multitude of proteins that form the axoneme and regulate its movement. Connections among the several sets of dyneins, in particular, suggest ways in which their actions may be coordinated. Study of the molecular architecture of isolated doublets has provided a structural basis for understanding the doublet's mechanical properties that are related to the bending of the axoneme, and has also offered insight into its potential role in the mechanism of dynein activity regulation.

  11. Dissipative Structures At Laser-Solid Interactions

    NASA Astrophysics Data System (ADS)

    Nanai, Laszlo

    1989-05-01

    The questions which are discussed in this lecture refer to one of sections of laser-solid interactions, namely: to formation of different dissipative structures on the surface of metals and semiconductors when they are irradiated by intensive laser light in chemically active media (f.e.air). Some particular examples of the development at different spatial and time instabilities, periodic and stochastic structures, auto-wave processes are present-ed using testing materials vanadium metal and semiconducting V205 single crystals and light sources: cw and pulsed CO2 and YAG lasers.

  12. Structural interaction with transportation and handling systems

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Problems involved in the handling and transportation of finished space vehicles from the factory to the launch site are presented, in addition to recommendations for properly accounting for in space vehicle structural design, adverse interactions during transportation. Emphasis is given to the protection of vehicle structures against those environments and loads encountered during transportation (including temporary storage) which would exceed the levels that the vehicle can safely withstand. Current practices for verifying vehicle safety are appraised, and some of the capabilities and limitations of transportation and handling systems are summarized.

  13. Soil/Structure Interactions in Earthquakes

    NASA Technical Reports Server (NTRS)

    Ramey, G. W.; Moore, R. K.; Yoo, C. H.; Bush, Thomas D., Jr.; Stallings, J. M.

    1986-01-01

    In effort to improve design of Earthquake-resistant structures, mathematical study undertaken to simulate interactions among soil, foundation, and superstructure during various kinds of vibrational excitation. System modeled as three lumped masses connected vertically by springs, with lowest mass connected to horizontal vibrator (representing ground) through springs and dashpot. Behavior of springs described by elastic or elastoplastic force/deformation relationships. Relationships used to approximate nonlinear system behavior and soil/foundation-interface behavior.

  14. A deployable structure and solar array controls experiment for STEP

    NASA Technical Reports Server (NTRS)

    Nishimoto, T. S.

    1984-01-01

    A candidate configuration for a controls experiment on the Space Technology Experiments Platform (STEP) is described. The elements of the experiment are the mast, the solar array, and an articulation module between the two. The characteristic dimensions are very compatible for integration on a pallet such a STEP's proposed configuration. The controls' objective would be the measurement of orbiter interaction as well as the system identification of the appendages. The flight experiment configuration would also provide a test bed for various active vibration controls concepts. The instrumentation being considered would measure accelerations, strains, displacements, and temperatures. The deployable mast has eight elements defining a structural bay. Uniaxial measurements would be required to define loads at a cross section of the structure. Displacements due to thermal distortion of the mast and the local state of the solar concentrator may be measured by an optical ranging technique from the orbiter aft flight deck.

  15. Computer Controlled Experiments Using the Interactive Microcomputer Peripheral.

    ERIC Educational Resources Information Center

    Howard, Edgar; Howard, Peter

    1985-01-01

    Describes the Interactive Microcomputer Peripheral (including major features, source, and current cost) and physics experiments using the instrument. The instrument can also be used for such purposes as counting, timing, and frequency measurement as well as for experiments in biology and experimental psychology. (JN)

  16. Flow Experiences of Children in an Interactive Social Game Environment

    ERIC Educational Resources Information Center

    Inal, Yavuz; Cagiltay, Kursat

    2007-01-01

    This study examines children's flow experiences in an interactive social game environment. A total of 33 children aged from 7 to 9 years participated in the study for 6 weeks. Data were collected through observations and interviews. In order to measure the flow experiences of the children, items of a flow scale were administered to the children…

  17. Statistical structure of host-phage interactions.

    PubMed

    Flores, Cesar O; Meyer, Justin R; Valverde, Sergi; Farr, Lauren; Weitz, Joshua S

    2011-07-12

    Interactions between bacteria and the viruses that infect them (i.e., phages) have profound effects on biological processes, but despite their importance, little is known on the general structure of infection and resistance between most phages and bacteria. For example, are bacteria-phage communities characterized by complex patterns of overlapping exploitation networks, do they conform to a more ordered general pattern across all communities, or are they idiosyncratic and hard to predict from one ecosystem to the next? To answer these questions, we collect and present a detailed metaanalysis of 38 laboratory-verified studies of host-phage interactions representing almost 12,000 distinct experimental infection assays across a broad spectrum of taxa, habitat, and mode of selection. In so doing, we present evidence that currently available host-phage infection networks are statistically different from random networks and that they possess a characteristic nested structure. This nested structure is typified by the finding that hard to infect bacteria are infected by generalist phages (and not specialist phages) and that easy to infect bacteria are infected by generalist and specialist phages. Moreover, we find that currently available host-phage infection networks do not typically possess a modular structure. We explore possible underlying mechanisms and significance of the observed nested host-phage interaction structure. In addition, given that most of the available host-phage infection networks examined here are composed of taxa separated by short phylogenetic distances, we propose that the lack of modularity is a scale-dependent effect, and then, we describe experimental studies to test whether modular patterns exist at macroevolutionary scales.

  18. INSPIRE - Premission. [Interactive NASA Space Physics Ionosphere Radio Experiment

    NASA Technical Reports Server (NTRS)

    Taylor, William W. L.; Mideke, Michael; Pine, William E.; Ericson, James D.

    1992-01-01

    The Interactive NASA Space Physics Ionosphere Radio Experiment (INSPIRE) designed to assist in a Space Experiments with Particle Accelerators (SEPAC) project is discussed. INSPIRE is aimed at recording data from a large number of receivers on the ground to determine the exact propagation paths and absorption of radio waves at frequencies between 50 Hz and 7 kHz. It is indicated how to participate in the experiment that will involve high school classes, colleges, and amateur radio operators.

  19. Apollo experience report: Spacecraft structural windows

    NASA Technical Reports Server (NTRS)

    Pigg, O. E.; Weiss, S. P.

    1973-01-01

    The window structural design and verification experience is presented for the Apollo command and lunar modules. This report presents window design philosophy, design criteria, hardware description, and qualification and acceptance test programs and discusses the problems encountered and solutions developed in these areas. The structural characteristics of glass are not generally well understood by designers. The optics and instrument glass covers were not considered to be structural components and thus were not normally subjected to the design, qualification, and acceptance standards necessary to preclude failures. These two factors contributed significantly to window problems on both Apollo spacecraft.

  20. Structural Priming and Frequency Effects Interact in Chinese Sentence Comprehension

    PubMed Central

    Wei, Hang; Dong, Yanping; Boland, Julie E.; Yuan, Fang

    2016-01-01

    Previous research in several European languages has shown that the language processing system is sensitive to both structural frequency and structural priming effects. However, it is currently not clear whether these two types of effects interact during online sentence comprehension, especially for languages that do not have morphological markings. To explore this issue, the present study investigated the possible interplay between structural priming and frequency effects for sentences containing the Chinese ambiguous construction V NP1 de NP2 in a self-paced reading experiment. The sentences were disambiguated to either the more frequent/preferred NP structure or the less frequent VP structure. Each target sentence was preceded by a prime sentence of three possible types: NP primes, VP primes, and neutral primes. When the ambiguous construction V NP1 de NP2 was disambiguated to the dispreferred VP structure, participants experienced more processing difficulty following an NP prime relative to following a VP prime or a neutral baseline. When the ambiguity was resolved to the preferred NP structure, prime type had no effect. These results suggest that structural priming in comprehension is modulated by the baseline frequency of alternative structures, with the less frequent structure being more subject to structural priming effects. These results are discussed in the context of the error-based, implicit learning account of structural priming. PMID:26869954

  1. The structure and dynamics of interactive documents

    SciTech Connect

    Rocha, J.T.

    1999-04-01

    Advances in information technology continue to accelerate as the new millennium approaches. With these advances, electronic information management is becoming increasingly important and is now supported by a seemingly bewildering array of hardware and software whose sole purpose is the design and implementation of interactive documents employing multimedia applications. Multimedia memory and storage applications such as Compact Disk-Read Only Memory (CD-ROMs) are already a familiar interactive tool in both the entertainment and business sectors. Even home enthusiasts now have the means at their disposal to design and produce CD-ROMs. More recently, Digital Video Disk (DVD) technology is carving its own niche in these markets and may (once application bugs are corrected and prices are lowered) eventually supplant CD-ROM technology. CD-ROM and DVD are not the only memory and storage applications capable of supporting interactive media. External, high-capacity drives and disks such as the Iomega{copyright} zip{reg_sign} and jaz{reg_sign} are also useful platforms for launching interactive documents without the need for additional hardware such as CD-ROM burners and copiers. The main drawback here, however, is the relatively high unit price per disk when compared to the unit cost of CD-ROMs. Regardless of the application chosen, there are fundamental structural characteristics that must be considered before effective interactive documents can be created. Additionally, the dynamics of interactive documents employing hypertext links are unique and bear only slight resemblance to those of their traditional hard-copy counterparts. These two considerations form the essential content of this paper.

  2. Simulation of the fine structure of the 12 July 1996 Stratosphere-Troposphere Experiment: Radiation, Aerosols and Ozone (STERAO-A) storm accounting for effects of terrain and interaction with mesoscale flow

    NASA Astrophysics Data System (ADS)

    Stenchikov, Georgiy; Pickering, Kenneth; Decaria, Alex; Tao, W.-K.; Scala, John; Ott, Lesley; Bartels, Diana; Matejka, Thomas

    2005-07-01

    Vertical mixing of chemical tracers and optically active constituents by deep convection affects regional and global chemical balances in the troposphere and lower stratosphere. This important process is not explicitly resolved in global and regional models and has to be parameterized. However, mixing depends strongly on the spatial structure, strength, and temporal evolution of the particular storm, complicating parameterization of this important effect in the large-scale models. To better quantify dynamic fields and associated mixing processes, we simulate a thunderstorm observed on 12 July 1996 during the STERAO-A (Stratosphere-Troposphere Experiment: Radiation, Aerosols, and Ozone) Deep Convection field project using the Goddard Cloud Ensemble (GCE) model. The 12 July STERAO-A storm had very complex temporal and spatial structure. The meteorological environment and evolution of the storm were significantly different than those of the 10 July STERAO-A storm extensively discussed in previous studies. Our 2-D and 3-D GCE model runs with uniform one-sounding initialization were unable to reproduce the full life cycle of the 12 July storm observed by the CHILL radar system. To describe the storm evolution, we modified the 3-D GCE model to include the effects of terrain and the capability of using nonuniform initial fields. We conducted a series of numerical experiments and reproduced the observed life cycle and fine spatial structure of the storm. The main characteristics of the 3-D simulation of the 12 July storm were compared with observations, with 2-D simulations of the same storm, and with the evolution of the 10 July storm. The simulated 3-D convection appears to be stronger and more realistic than in our 2-D simulations. Having developed in a less unstable environment than the 10 July 1996 STERAO-A storm, our simulation of the 12 July storm produced weaker but sustainable convection that was significantly fed by wind shear instability in the lower troposphere

  3. Fluid-structure interaction of reticulated porous wings

    NASA Astrophysics Data System (ADS)

    Strong, Elizabeth; Jawed, Mohammad; Reis, Pedro

    Insects of the orders Neuroptera and Hymenoptera locomote via flapping flight with reticulated wings that have porous structures that confers them with remarkable lightweight characteristics. Yet these porous wings still perform as contiguous plates to provide the necessary aerodynamic lift and drag required for flight. Even though the fluid flow past the bulk of these insects may be in high Reynolds conditions, viscosity can dominate over inertia in the flow through the porous sub-features. Further considering the flexibility of these reticulated wings yields a highly nonlinear fluid-structure interaction problem. We perform a series of dynamically-scaled precision model experiments to gain physical insight into this system. Our experiments are complemented with computer simulations that combine the Discrete Elastic Rods method and a model for the fluid loading that takes into account the `leakiness' through the porous structure. Our results are anticipated to find applications in micro-air vehicle aerodynamics.

  4. Structures in multiple spin-2 interactions

    NASA Astrophysics Data System (ADS)

    Baldacchino, Oliver; Schmidt-May, Angnis

    2017-04-01

    We study generalisations of ghost-free bimetric theory which involve more than two spin-2 fields. The consistent interactions can enter in the form of two different couplings and in the majority of this work we concentrate on the simpler one. The corresponding action involves one metric coupled to N tensor fields which do not interact with each other. We derive maximally symmetric solutions to the multimetric equations of motion and identify the mass eigenstates in the linearised theory around these backgrounds. Our results are then applied to the problem of singling out multimetric models which possess certain additional structures. In particular, we look for a relation between scale invariant background solutions, the perturbative emergence of Weyl invariance and the presence of partially massless spin-2 fields in the linear theory. Our findings generalise known results in bimetric theory and allow us to point out similarities and differences between the bi- and multimetric models.

  5. Engineering Structurally Interacting RNA (sxRNA).

    PubMed

    Doyle, Francis; Lapsia, Sameer; Spadaro, Salvatore; Wurz, Zachary E; Bhaduri-McIntosh, Sumita; Tenenbaum, Scott A

    2017-03-28

    RNA-based three-way junctions (3WJs) are naturally occurring structures found in many functional RNA molecules including rRNA, tRNA, snRNA and ribozymes. 3WJs are typically characterized as resulting from an RNA molecule folding back on itself in cis but could also form in trans when one RNA, for instance a microRNA binds to a second structured RNA, such as a mRNA. Trans-3WJs can influence the final shape of one or both of the RNA molecules and can thus provide a means for modulating the availability of regulatory motifs including potential protein or microRNA binding sites. Regulatory 3WJs generated in trans represent a newly identified regulatory category that we call structurally interacting RNA or sxRNA for convenience. Here we show that they can be rationally designed using familiar cis-3WJ examples as a guide. We demonstrate that an sxRNA "bait" sequence can be designed to interact with a specific microRNA "trigger" sequence, creating a regulatable RNA-binding protein motif that retains its functional activity. Further, we show that when placed downstream of a coding sequence, sxRNA can be used to switch "ON" translation of that sequence in the presence of the trigger microRNA and the amount of translation corresponded with the amount of microRNA present.

  6. Engineering Structurally Interacting RNA (sxRNA)

    PubMed Central

    Doyle, Francis; Lapsia, Sameer; Spadaro, Salvatore; Wurz, Zachary E.; Bhaduri-McIntosh, Sumita; Tenenbaum, Scott A.

    2017-01-01

    RNA-based three-way junctions (3WJs) are naturally occurring structures found in many functional RNA molecules including rRNA, tRNA, snRNA and ribozymes. 3WJs are typically characterized as resulting from an RNA molecule folding back on itself in cis but could also form in trans when one RNA, for instance a microRNA binds to a second structured RNA, such as a mRNA. Trans-3WJs can influence the final shape of one or both of the RNA molecules and can thus provide a means for modulating the availability of regulatory motifs including potential protein or microRNA binding sites. Regulatory 3WJs generated in trans represent a newly identified regulatory category that we call structurally interacting RNA or sxRNA for convenience. Here we show that they can be rationally designed using familiar cis-3WJ examples as a guide. We demonstrate that an sxRNA “bait” sequence can be designed to interact with a specific microRNA “trigger” sequence, creating a regulatable RNA-binding protein motif that retains its functional activity. Further, we show that when placed downstream of a coding sequence, sxRNA can be used to switch “ON” translation of that sequence in the presence of the trigger microRNA and the amount of translation corresponded with the amount of microRNA present. PMID:28350000

  7. User experience interaction design for digital educational games

    NASA Astrophysics Data System (ADS)

    Yuan, Jiugen; Zhang, Wenting; Xing, Ruonan

    2014-04-01

    Leading the elements of games into education is the newest teaching concepts in the field of educational technology, which is by using healthy games to impel and preserve the learner's motivation, improve the learning efficiency and bring one experience in learning something by playing games. First of all, this article has introduced the concept of Digital Game and User Experience and brought the essence of Digital Game to light to construct the frame of user experience interaction design for digital educational games and offer one design idea for the development of related products and hoping that Digital Game will bring us continuous innovation experience.

  8. PrP charge structure encodes interdomain interactions

    PubMed Central

    Martínez, Javier; Sánchez, Rosa; Castellanos, Milagros; Makarava, Natallia; Aguzzi, Adriano; Baskakov, Ilia V.; Gasset, María

    2015-01-01

    Almost all proteins contain charged residues, and their chain distribution is tailored to fulfill essential ionic interactions for folding, binding and catalysis. Among proteins, the hinged two-domain chain of the cellular prion protein (PrPC) exhibits a peculiar charge structure with unclear consequences in its structural malleability. To decipher the charge design role, we generated charge-reverted mutants for each domain and analyzed their effect on conformational and metabolic features. We found that charges contain the information for interdomain interactions. Use of dynamic light scattering and thermal denaturation experiments delineates the compaction of the α-fold by an electrostatic compensation between the polybasic 23–30 region and the α3 electronegative surface. This interaction increases stability and disfavors fibrillation. Independently of this structural effect, the N-terminal electropositive clusters regulate the α-cleavage efficiency. In the fibrillar state, use of circular dichroism, atomic-force and fluorescence microscopies reveal that the N-terminal positive clusters and the α3 electronegative surface dictate the secondary structure, the assembly hierarchy and the growth length of the fibril state. These findings show that the PrP charge structure functions as a code set up to ensure function and reduce pathogenic routes. PMID:26323476

  9. Solar Array Module Plasma Interaction Experiment (SAMPIE): Technical requirements document

    NASA Technical Reports Server (NTRS)

    Hillard, G. Barry; Ferguson, Dale C.

    1992-01-01

    The Solar Array Module Plasma Interactions Experiment (SAMPIE) is a NASA shuttle space flight experiment scheduled for launch in early 1994. The SAMPIE experiment will investigate plasma interactions of high voltage space power systems in low earth orbit. Solar cell modules, representing several technologies, will be biased to high voltages to characterize both arcing and plasma current collection. Other solar modules, specially modified in accordance with current theories of arcing and breakdown, will demonstrate the possibility of arc suppression. Finally, several test modules will be included to study the basic nature of these interactions. The science and technology goals for the project are defined in the Technical Requirements Document (TRD) which is presented here.

  10. The Plasma Interaction Experiment (PIX) description and test program. [electrometers

    NASA Technical Reports Server (NTRS)

    Ignaczak, L. R.; Haley, F. A.; Domino, E. J.; Culp, D. H.; Shaker, F. J.

    1978-01-01

    The plasma interaction experiment (PIX) is a battery powered preprogrammed auxiliary payload on the LANDSAT-C launch. This experiment is part of a larger program to investigate space plasma interactions with spacecraft surfaces and components. The varying plasma densities encountered during available telemetry coverage periods are deemed sufficient to determine first order interactions between the space plasma environment and the biased experimental surfaces. The specific objectives of the PIX flight experiment are to measure the plasma coupling current and the negative voltage breakdown characteristics of a solar array segment and a gold plated steel disk. Measurements will be made over a range of surface voltages up to plus or minus kilovolt. The orbital environment will provide a range of plasma densities. The experimental surfaces will be voltage biased in a preprogrammed step sequence to optimize the data returned for each plasma region and for the available telemetry coverage.

  11. Inquiry style interactive virtual experiments: a case on circular motion

    NASA Astrophysics Data System (ADS)

    Zhou, Shaona; Han, Jing; Pelz, Nathaniel; Wang, Xiaojun; Peng, Liangyu; Xiao, Hua; Bao, Lei

    2011-11-01

    Interest in computer-based learning, especially in the use of virtual reality simulations is increasing rapidly. While there are good reasons to believe that technologies have the potential to improve teaching and learning, how to utilize the technology effectively in teaching specific content difficulties is challenging. To help students develop robust understandings of correct physics concepts, we have developed interactive virtual experiment simulations that have the unique feature of enabling students to experience force and motion via an analogue joystick, allowing them to feel the applied force and simultaneously see its effects. The simulations provide students learning experiences that integrate both scientific representations and low-level sensory cues such as haptic cues under a single setting. In this paper, we introduce a virtual experiment module on circular motion. A controlled study has been conducted to evaluate the impact of using this virtual experiment on students' learning of force and motion in the context of circular motion. The results show that the interactive virtual experiment method is preferred by students and is more effective in helping students grasp the physics concepts than the traditional education method such as problem-solving practices. Our research suggests that well-developed interactive virtual experiments can be useful tools in teaching difficult concepts in science.

  12. Active aerodynamic control of wake-airfoil interaction noise - Experiment

    NASA Astrophysics Data System (ADS)

    Simonich, J. C.; Lavrich, P. L.; Sofrin, T. G.; Topol, D. A.

    A proof of concept experiment is conducted that shows the potential for active aerodynamic control of rotor wake/stator interaction noise in a simplified manner. A single airfoil model representing the stator was fitted with a moveable trailing edge flap controlled by a servo motor. The control system moves the motor driven flap in the correct angular displacement phase and rate to reduce the unsteady load on the airfoil during the wake interaction.

  13. A slewing control experiment for flexible structures

    NASA Technical Reports Server (NTRS)

    Juang, J.-N.; Horta, L. G.; Robertshaw, H. H.

    1985-01-01

    A hardware set-up has been developed to study slewing control for flexible structures including a steel beam and a solar panel. The linear optimal terminal control law is used to design active controllers which are implemented in an analog computer. The objective of this experiment is to demonstrate and verify the dynamics and optimal terminal control laws as applied to flexible structures for large angle maneuver. Actuation is provided by an electric motor while sensing is given by strain gages and angle potentiometer. Experimental measurements are compared with analytical predictions in terms of modal parameters of the system stability matrix and sufficient agreement is achieved to validate the theory.

  14. Optimal Force Generation with Fluid-Structure Interactions

    NASA Astrophysics Data System (ADS)

    Peng, Diing-wen

    Typical computational and experimental methods are unsuitable for studying large scale optimization problems involving complex fluid structure interactions, primarily due to their time-consuming nature. A novel experimental approach is proposed here that provides a high-fidelity and efficient alternative to discover optimal parameters arising from the passive interaction between structural elasticity and fluid dynamic forces. This approach utilizes motors, force transducers, and active controllers to emulate the effects of elasticity, eliminating the physical need to replace structural components in the experiment. A clustering genetic algorithm is then used to tune the structural parameters to achieve desired optimality conditions, resulting in approximated global optimal regions within the search bound. A prototype fluid-structure interaction experiment inspired by the lift generation of flapping wing insects is presented to highlight the capabilities of this approach. The experiment aims to maximize the average lift on a sinusoidally translating plate, by optimizing the damping ratio and natural frequency of the plate's elastic pitching dynamics. Reynolds number, chord length, and stroke length are varied between optimizations to explore their relationships to the optimal structural parameters. The results reveal that only limited ranges of stroke lengths are conducive to lift generation; there also exists consistent trends between optimal stroke length, natural frequency, and damping ratio. The measured lift, pitching angle, and torque on the plate for optimal scenarios exhibit the same frequency as the translation frequency, and the phase angles of the optimal structural parameters at this frequency are found to be independent of the stroke length. This critical phase can be then characterized by a linear function of the chord length and Reynolds number. Particle image velocimetry measurements are acquired for the kinematics generated with optimal and

  15. Ten years of experience from interactive ergonomics projects.

    PubMed

    Eklund, J; Karltun, J

    2012-01-01

    This paper highlights experiences from ergonomics projects, applying an interactive research approach. The aim of this paper is to summarise experiences from seven interactive ergonomics projects with the aim to improve ergonomics and organizational performance jointly. Results from these seven projects were analysed with a model for assessing sustainable change, including the factors active ownership, professional management, competent project leadership, and involved participants. All factors were found giving support to impact and sustainability of the change projects. However, the role of the researcher is difficult and demanding.

  16. Progress on control experiments of flexible structures

    NASA Technical Reports Server (NTRS)

    Juang, Jer-Nan

    1990-01-01

    Progress at the NASA Langley Research Center in the area of control experiments for flexible structures is described. First the author presents the experimental results for a linear model which represents slewing maneuvers of a generic space station solar panel carried out to evaluate experimentally some control technologies. Then the status of the rotational/translational maneuvering experiment of a flexible steel panel carried by a translation cart is presented. Finally, experimental results of the NASA minimast testbed using velocity command stepper motors as reaction mass reactors are shown. All the test configurations are briefly described, including actuator and sensor, test setup, and test software. The status of some research activities oriented primarily to the experimental methods for control of flexible structures is presented.

  17. Control/structure interaction conceptual design tool

    NASA Technical Reports Server (NTRS)

    Briggs, Hugh C.

    1990-01-01

    The JPL Control/Structure Interaction Program is developing new analytical methods for designing micro-precision spacecraft with controlled structures. One of these, the Conceptual Design Tool, will illustrate innovative new approaches to the integration of multi-disciplinary analysis and design methods. The tool will be used to demonstrate homogeneity of presentation, uniform data representation across analytical methods, and integrated systems modeling. The tool differs from current 'integrated systems' that support design teams most notably in its support for the new CSI multi-disciplinary engineer. The design tool will utilize a three dimensional solid model of the spacecraft under design as the central data organization metaphor. Various analytical methods, such as finite element structural analysis, control system analysis, and mechanical configuration layout, will store and retrieve data from a hierarchical, object oriented data structure that supports assemblies of components with associated data and algorithms. In addition to managing numerical model data, the tool will assist the designer in organizing, stating, and tracking system requirements.

  18. Advanced accelerating structures and their interaction with electron beams.

    SciTech Connect

    Gai, W.; High Energy Physics

    2008-01-01

    In this paper, we give a brief description of several advanced accelerating structures, such as dielectric loaded waveguides, photonic band gap, metamaterials and improved iris-loaded cavities. We describe wakefields generated by passing high current electron beams through these structures, and applications of wakefields to advanced accelerator schemes. One of the keys to success for high gradient wakefield acceleration is to develop high current drive beam sources. As an example, the high current RF photo injector at the Argonne Wakefield Accelerator, passed a {approx}80 nC electron beam through a high gradient dielectric loaded structure to achieve a 100 MV/m gradient. We will summarize recent related experiments on beam-structure interactions and also discuss high current electron beam generation and propagation and their applications to wakefield acceleration.

  19. Advanced Accelerating Structures and Their Interaction with Electron Beams

    SciTech Connect

    Gai Wei

    2009-01-22

    In this paper, we give a brief description of several advanced accelerating structures, such as dielectric loaded waveguides, photonic band gap, metamaterials and improved iris-loaded cavities. We describe wakefields generated by passing high current electron beams through these structures, and applications of wakefields to advanced accelerator schemes. One of the keys to success for high gradient wakefield acceleration is to develop high current drive beam sources. As an example, the high current RF photo injector at the Argonne Wakefield Accelerator, passed a {approx}80 nC electron beam through a high gradient dielectric loaded structure to achieve a 100 MV/m gradient. We will summarize recent related experiments on beam-structure interactions and also discuss high current electron beam generation and propagation and their applications to wakefield acceleration.

  20. Simulated Interactive Research Experiments as Educational Tools for Advanced Science.

    PubMed

    Tomandl, Mathias; Mieling, Thomas; Losert-Valiente Kroon, Christiane M; Hopf, Martin; Arndt, Markus

    2015-09-15

    Experimental research has become complex and thus a challenge to science education. Only very few students can typically be trained on advanced scientific equipment. It is therefore important to find new tools that allow all students to acquire laboratory skills individually and independent of where they are located. In a design-based research process we have investigated the feasibility of using a virtual laboratory as a photo-realistic and scientifically valid representation of advanced scientific infrastructure to teach modern experimental science, here, molecular quantum optics. We found a concept based on three educational principles that allows undergraduate students to become acquainted with procedures and concepts of a modern research field. We find a significant increase in student understanding using our Simulated Interactive Research Experiment (SiReX), by evaluating the learning outcomes with semi-structured interviews in a pre/post design. This suggests that this concept of an educational tool can be generalized to disseminate findings in other fields.

  1. Simulated Interactive Research Experiments as Educational Tools for Advanced Science

    PubMed Central

    Tomandl, Mathias; Mieling, Thomas; Losert-Valiente Kroon, Christiane M.; Hopf, Martin; Arndt, Markus

    2015-01-01

    Experimental research has become complex and thus a challenge to science education. Only very few students can typically be trained on advanced scientific equipment. It is therefore important to find new tools that allow all students to acquire laboratory skills individually and independent of where they are located. In a design-based research process we have investigated the feasibility of using a virtual laboratory as a photo-realistic and scientifically valid representation of advanced scientific infrastructure to teach modern experimental science, here, molecular quantum optics. We found a concept based on three educational principles that allows undergraduate students to become acquainted with procedures and concepts of a modern research field. We find a significant increase in student understanding using our Simulated Interactive Research Experiment (SiReX), by evaluating the learning outcomes with semi-structured interviews in a pre/post design. This suggests that this concept of an educational tool can be generalized to disseminate findings in other fields. PMID:26370627

  2. The Photogrammetric Appendage Structural Dynamics Experiment

    NASA Astrophysics Data System (ADS)

    Gilbert, Michael G.; Welch, Sharon S.; Moore, Christopher L.

    1995-09-01

    The Photogrammetric Appendage Structural Dynamics Experiment (PASDE) is a Hitchhiker payload scheduled to fly as part of the International Space Station (ISS) Phase-1 flight program to the Russian Space Station Mir. The objective of the first flight of PASDE on STS-74 is to obtain video images of the Mir Kvant-2 solar array response to various structural dynamic excitation events. This experiment will demonstrate the use of photogrammetric techniques for on-orbit structural dynamics measurements. Photogrammetric measurements will provide a low cost alternative to appendage mounted accelerometers to the ISS program. The PASDE experiment hardware consists of three instruments each containing two video cameras, two video tape recorders, a modified video signal time inserter, and associated avionics boxes. The instruments were designed and built at the NASA Langley Research Center, and are integrated into standard Hitchhiker canisters at the NASA Goddard Space Flight Center. The Hitchhiker canisters are then installed into the Space Shuttle cargo bay in locations selected to achieve good video coverage and photogrammetric geometry. The measurement resolution of the instruments is expected to be on the order of 0.25 cm (0.1 in.).

  3. The Photogrammetric Appendage Structural Dynamics Experiment

    NASA Technical Reports Server (NTRS)

    Gilbert, Michael G.; Welch, Sharon S.; Moore, Christopher L.

    1995-01-01

    The Photogrammetric Appendage Structural Dynamics Experiment (PASDE) is a Hitchhiker payload scheduled to fly as part of the International Space Station (ISS) Phase-1 flight program to the Russian Space Station Mir. The objective of the first flight of PASDE on STS-74 is to obtain video images of the Mir Kvant-2 solar array response to various structural dynamic excitation events. This experiment will demonstrate the use of photogrammetric techniques for on-orbit structural dynamics measurements. Photogrammetric measurements will provide a low cost alternative to appendage mounted accelerometers to the ISS program. The PASDE experiment hardware consists of three instruments each containing two video cameras, two video tape recorders, a modified video signal time inserter, and associated avionics boxes. The instruments were designed and built at the NASA Langley Research Center, and are integrated into standard Hitchhiker canisters at the NASA Goddard Space Flight Center. The Hitchhiker canisters are then installed into the Space Shuttle cargo bay in locations selected to achieve good video coverage and photogrammetric geometry. The measurement resolution of the instruments is expected to be on the order of 0.25 cm (0.1 in.).

  4. Physical scale experiments on torrential filter structures

    NASA Astrophysics Data System (ADS)

    Chiari, Michael; Moser, Markus; Trojer, Martin; Hübl, Johannes

    2016-04-01

    In the framework of the INTERREG Project "SedAlp" physical scale model experiments are carried out in the hydraulic laboratory of the Institute of Mountain Risk Engineering at the University of Life Sciences in Vienna in order to optimize torrent protection structures. Two different types of check dams are investigated. A screen-dam with inclined vertical beams is compared with a beam-dam with horizontal beams. The experiments evaluate the variation of sediment transport of these structures including the influence of coarse woody debris. Therefore the distance between the steel elements can be adjusted to show their ability to filter sediment. The physical scale of the experiments is 1:30. All experimental runs are Froude scaled. Both dams are tested in elongated and pear-shaped sediment retention basins in order to investigate the shape effect of the deposition area. For a systematic comparison of the two check dams experiments with fluvial bedload transport are made. First a typical hydrograph for an extreme flood with unlimited sediment supply is modelled. A typical torrential sediment mixture with a wide grain-size distribution is fed by a conveyor belt according the transport capacity of the upstream reach. Then the deposition is scanned with a laser-scan device in order to analyse the deposition pattern and the deposited volume. Afterwards a flood with a lower reoccurrence period without sediment transport from upstream is modelled to investigate the ability of the protection structure for self-emptying. To investigate the influence of driftwood on the deposition behaviour experiments with logs are made. Different log diameters and lengths are added upstream the basin. The results show, that the deposition during the experiments was not controlled by sorting-effects at the location of the dam. The deposition always started from upstream, where the transport capacity was reduced due to the milder slope and the widening of the basin. No grain sorting effects

  5. Interactions and Practices to Enhance the Inclusion Experience

    ERIC Educational Resources Information Center

    Tobin, Ruthanne

    2007-01-01

    In a collaborative research project, two inclusion teachers and their principal demonstrate ways to enhance the inclusion experience for five exceptional students: four with mild intellectual disabilities and one with a learning disability. The findings revealed that one teacher engaged in positive interactions in the classroom by positioning the…

  6. Interaction and the structures of coal

    NASA Astrophysics Data System (ADS)

    Opaprakasit, Pakorn

    The origin of a decrease in the amount of soluble material from coal upon a reflux treatment has been investigated in an attempt to obtain insight into the nature of the interaction in the macromolecular network structure of coal. This decrease in the extractable material is a result of an increase in the amount of physical cross-links associated with secondary interactions. The alternate possibility of covalent cross-link formation by ether linkage was found to be unlikely because the coal hydroxyl content remains unchanged upon heat treatment. The functional groups responsible for forming these physical cross-links and their contents vary from coal to coal with coal rank. Carboxylate/cation complexes, similar to those found in ionomers, dominate in low rank coal. In high rank coal, the clusters involving pi-cation interactions were observed. Both mechanisms seem to play a role in mid rank coals. These physical cross-links are responsible for a lowering of the extraction yield of coal, but are disrupted by a treatment with acid solution, resulting in an increase in the extraction yield. As a consequence, the cross-links in coal structure should be classified into two types; a "permanent" covalent cross-link, which break under extreme conditions such as chemical reaction and pyrolysis, and "reversible" cross-links, largely associated with ionomer-like structure and pi-cation interactions. The interaction between a "magic" solvent of N-methylpyrollidone and carbon disulfide (NMP/CS2) and its role in the unusual extractability enhancement of Upper Freeport coal has also been investigated. The results strongly suggest that NMP/CS2 mixed solvents form complexes with cations. These mixed solvents are capable of forming a solid complex with cations from NaOH and some simple salts, such as NaCl and LiCl. Given that Upper Freeport coal contains a large amount of mineral matter, it is not surprising that these types of complexes could be formed in the present of the mixed

  7. Interactive Plasma Physics Education Using Data from Fusion Experiments

    NASA Astrophysics Data System (ADS)

    Calderon, Brisa; Davis, Bill; Zwicker, Andrew

    2010-11-01

    The Internet Plasma Physics Education Experience (IPPEX) website was created in 1996 to give users access to data from plasma and fusion experiments. Interactive material on electricity, magnetism, matter, and energy was presented to generate interest and prepare users to understand data from a fusion experiment. Initially, users were allowed to analyze real-time and archival data from the Tokamak Fusion Test Reactor (TFTR) experiment. IPPEX won numerous awards for its novel approach of allowing users to participate in ongoing research. However, the latest revisions of IPPEX were in 2001 and the interactive material is no longer functional on modern browsers. Also, access to real-time data was lost when TFTR was shut down. The interactive material on IPPEX is being rewritten in ActionScript3.0, and real-time and archival data from the National Spherical Tokamak Experiment (NSTX) will be made available to users. New tools like EFIT animations, fast cameras, and plots of important plasma parameters will be included along with an existing Java-based ``virtual tokamak.'' Screenshots from the upgraded website and future directions will be presented.

  8. MINER{nu}A, a Neutrino--Nucleus Interaction Experiment

    SciTech Connect

    Solano Salinas, C. J.; Chamorro, A.; Romero, C.

    2007-10-26

    With the fantastic results of KamLAND and SNO for neutrino physics, a new generation of neutrino experiments are being designed and build, specially to study the neutrino oscillations to resolve most of the incognita still we have in the neutrino physics. At FERMILAB we have the experiments MINOS and, in a near future, NO{nu}A, to study this kind of oscillations. One big problem these experiments will have is the lack of a good knowledge of the Physics of neutrino interactions with matter, and this will generate big systematic errors. MINER{nu}A, also at FERMILAB, will cover this space studying with high statistics and great precision the neutrino--nucleus interactions.

  9. VLF wave-wave interaction experiments in the magnetosphere

    NASA Technical Reports Server (NTRS)

    Chang, D. C. D.

    1978-01-01

    VLF wave-wave interaction experiments were carried out by injecting various forms of VLF pulses into the magnetosphere from a 21.2 km dipole antenna at Siple, Antarctica. The injected signals propagate along a geomagnetic field line and often interact strongly with energetic electrons trapped in the radiation belts near the equator. Signals may be amplified and trigger emissions. These signals may then interact with one another through these energetic electrons. This report is divided into three parts. In the first part, simulations of VLF pulses propagating in the magnetosphere are carried out. In the second part, it is found for the first time that a 10 ms gap in a triggering wave can induce emission, which may then interact with the post-gap signals. In the third part, sideband triggering is reported for the first time.

  10. Early steps towards quarks and their interactions using neutrino beams in CERN bubble chamber experiments

    NASA Astrophysics Data System (ADS)

    Perkins, Don H.

    2016-06-01

    Results from neutrino experiments at CERN in the1970's, using bubble chamber detectors filled with heavy liquids, gave early evidence for the existence of quarks and gluons as real dynamical objects. In detail, the measured moments of the non-singlet structure functions provided crucial support for the validity of the present theory of the strong inter-quark interactions, quantum chromodynamics.

  11. Nucleon structure and the high energy interactions

    NASA Astrophysics Data System (ADS)

    Selyugin, O. V.

    2015-06-01

    On the basis of the representation of the generalized structure of nucleons a new model of the hadron interaction at high energies is presented. A new t dependence of the generalized parton distributions is obtained from the comparative analysis of different sets of the parton distribution functions, based on the description of the entire set of experimental data for the electromagnetic form factors of the proton and neutron. Taking into account the different moments of the generalized parton distributions of the hadron, quantitative descriptions of all existing experimental data of the proton-proton and proton-antiproton elastic scatterings from √{s }=9.8 GeV to 8 TeV, including the Coulomb range and large momentum transfers up to -t =15 GeV2 , are obtained with a few free high-energy fitting parameters. The real part of the hadronic elastic scattering amplitude is determined only through the complex s that satisfies the dispersion relations. The negligible contributions of the hard Pomeron and the presence of the non-small contributions of the maximal Odderon are obtained. The non-dying form of the spin-flip amplitude is examined as well. The structures of the Born term and unitarized scattering amplitude are analyzed. It is shown that the black disk limit for the elastic scattering amplitude is not reached at LHC energies. Predictions for LHC energies are made.

  12. Telescience operations with the solar array module plasma interaction experiment

    NASA Technical Reports Server (NTRS)

    Wald, Lawrence W.; Bibyk, Irene K.

    1995-01-01

    The Solar Array Module Plasma Interactions Experiment (SAMPIE) is a flight experiment that flew on the Space Shuttle Columbia (STS-62) in March 1994, as part of the OAST-2 mission. The overall objective of SAMPIE was to determine the adverse environmental interactions within the space plasma of low earth orbit (LEO) on modern solar cells and space power system materials which are artificially biased to high positive and negative direct current (DC) voltages. The two environmental interactions of interest included high voltage arcing from the samples to the space plasma and parasitic current losses. High voltage arcing can cause physical damage to power system materials and shorten expected hardware life. parasitic current losses can reduce power system efficiency because electric currents generated in a power system drain into the surrounding plasma via parasitic resistance. The flight electronics included two programmable high voltage DC power supplies to bias the experiment samples, instruments to measure the surrounding plasma environment in the STS cargo bay, and the on-board data acquisition system (DAS). The DAS provided in-flight experiment control, data storage, and communications through the Goddard Space Flight Center (GSFC) Hitchhiker flight avionics to the GSFC Payload Operations Control Center (POCC). The DAS and the SAMPIE POCC computer systems were designed for telescience operations; this paper will focus on the experiences of the SAMPIE team regarding telescience development and operations from the GSFC POCC during STS-62. The SAMPIE conceptual development, hardware design, and system verification testing were accomplished at the NASA Lewis Research Center (LeRC). SAMPIE was developed under the In-Space Technology Experiment Program (IN-STEP), which sponsors NASA, industry, and university flight experiments designed to enable and enhance space flight technology. The IN-STEP Program is sponsored by the Office of Space Access and Technology (OSAT).

  13. Interactive Lecture Experiments in Large Introductory Physics Classes

    NASA Astrophysics Data System (ADS)

    Milner-Bolotin, Marina M.; Kotlicki, A.; Rieger, G.; Bates, F.; Moll, R.; McPhee, K.; Nashon, S.

    2006-12-01

    We describe Interactive Lecture Experiments (ILE), which build on Interactive Lecture Demonstrations proposed by Sokoloff and Thornton (2004) and extends it by providing students with the opportunity to analyze experiments demonstrated in the lecture outside of the classroom. Real time experimental data is collected, using Logger Pro combined with the digital video technology. This data is uploaded to the Internet and made available to the students for further analysis. Student learning is assessed in the following lecture using conceptual questions (clickers). The goal of this project is to use ILE to make large lectures more interactive and promote student interest in science, critical thinking and data analysis skills. We report on the systematic study conducted using the Colorado Learning Attitudes about Science Survey, Force Concept Inventory, open-ended physics problems and focus group interviews to determine the impact of ILE on student academic achievement, motivation and attitudes towards physics. Three sections of students (750 students) experienced four ILE experiments. The surveys were administered twice and academic results for students who experienced the ILE for a particular topic were compared to the students, from a different section, who did not complete the ILE for that topic. Additional qualitative data on students’ attitudes was collected using open ended survey questions and interviews. We will present preliminary conclusions about the role of ILEs as an effective pedagogy in large introductory physics courses. Sokoloff, D.R. and R.K. Thornton (2004). Interactive Lecture Demonstrations: Active Learning in Introductory Physics, J.Wiley & Sons, INC. Interactive Lecture Experiments: http://www.physics.ubc.ca/ year1lab/p100/LectureLabs/lectureLabs.html

  14. The FrPNC Experiment, weak interaction studies in Francium at TRIUMF

    NASA Astrophysics Data System (ADS)

    Gomez, E.; Aubin, S.; Collister, R.; Behr, J. A.; Gwinner, G.; Orozco, L. A.; Pearson, M. R.; Tandecki, M.; Sheng, D.; Zhang, J.

    2012-09-01

    Francium is an excellent system to study the nuclear weak force due to its large nucleus and relatively simple atomic structure. The FrPNC experiment has a facility to produce cold trapped atomic francium samples for parity non-conservation studies. We are preparing to measure both the nuclear spin independent and dependent parts of the weak interaction in francium. The first one gives information about weak neutral currents at low energies, while the second one is sensitive to weak interactions between nucleons. We present the current status of the experiment.

  15. Plasma-materials interactions during rf experiments in tokamaks

    SciTech Connect

    Cohen, S.A.; Bernabei, S.; Budny, R.; Chu, T.K.; Colestock, P.; Hinnov, E.; Hooke, W.; Hosea, J.; Hwang, D.; Jobes, F.

    1984-09-01

    Plasma-materials interactions studied in recent ICRF heating and lower hybrid current drive experiments are reviewed. The microscopic processes responsible for impurity generation are discussed. In ICRF experiments, improvements in machine operation and in antenna and feedthrough design have allowed efficient plasma heating at RF powers up to 3 MW. No significant loss of energy from the plasma core due to impurity radiation occurs. Lower hybrid current drive results in the generation and maintenance of hundreds of kiloamperes of plasma current carried by suprathermal electrons. The loss of these electrons and their role in impurity generation are assessed. Methods to avoid this problem are evaluated.

  16. Acoustic-structure interaction problems. Final report

    SciTech Connect

    Love, E.; Taylor, R.L.

    1993-12-01

    The purpose of this report is to compare and evaluate different numerical methods for solving problems of interaction between elastic solids and acoustic fluids. In particular, we concentrate our efforts on solution techniques involving the finite element method. To that end, in Chapter 2 we discuss different options for analysis of infinite fluids. In particular, the method of mesh trunction and the use of radiation elements and the use of infinite elements are discussed. Also discussed is the analysis of scattering from rigid boundaries. Chapter 3 is a brief discussion of finite element formulations for elastic solids. We review the development, of two dimensional plane strain elements and one dimensional plate and shell elements. In Chapter 4, there is a discussion of the method used to couple the solid and the fluid. We give examples for solution of scattering of pressure waves from thin elastic shell structures. Chapter 5 is a brief conclusion of results and includes recommendations for the best methods of solution and additional research.

  17. U.S. perspective on technology demonstration experiments for adaptive structures

    NASA Technical Reports Server (NTRS)

    Aswani, Mohan; Wada, Ben K.; Garba, John A.

    1991-01-01

    Evaluation of design concepts for adaptive structures is being performed in support of several focused research programs. These include programs such as Precision Segmented Reflector (PSR), Control Structure Interaction (CSI), and the Advanced Space Structures Technology Research Experiment (ASTREX). Although not specifically designed for adaptive structure technology validation, relevant experiments can be performed using the Passive and Active Control of Space Structures (PACOSS) testbed, the Space Integrated Controls Experiment (SPICE), the CSI Evolutionary Model (CEM), and the Dynamic Scale Model Test (DSMT) Hybrid Scale. In addition to the ground test experiments, several space flight experiments have been planned, including a reduced gravity experiment aboard the KC-135 aircraft, shuttle middeck experiments, and the Inexpensive Flight Experiment (INFLEX).

  18. Computational and experimental techniques for coupled acoustic/structure interactions.

    SciTech Connect

    Sumali, Anton Hartono; Pierson, Kendall Hugh; Walsh, Timothy Francis; Dohner, Jeffrey Lynn; Reese, Garth M.; Day, David Minot

    2004-01-01

    This report documents the results obtained during a one-year Laboratory Directed Research and Development (LDRD) initiative aimed at investigating coupled structural acoustic interactions by means of algorithm development and experiment. Finite element acoustic formulations have been developed based on fluid velocity potential and fluid displacement. Domain decomposition and diagonal scaling preconditioners were investigated for parallel implementation. A formulation that includes fluid viscosity and that can simulate both pressure and shear waves in fluid was developed. An acoustic wave tube was built, tested, and shown to be an effective means of testing acoustic loading on simple test structures. The tube is capable of creating a semi-infinite acoustic field due to nonreflecting acoustic termination at one end. In addition, a micro-torsional disk was created and tested for the purposes of investigating acoustic shear wave damping in microstructures, and the slip boundary conditions that occur along the wet interface when the Knudsen number becomes sufficiently large.

  19. Approaches to Testing Interaction Effects Using Structural Equation Modeling Methodology.

    ERIC Educational Resources Information Center

    Li, Fuzhong; Harmer, Peter; Duncan, Terry E.; Duncan, Susan C.; Acock, Alan; Boles, Shawn

    1998-01-01

    Reviews a single indicator approach and multiple indicator approaches that simplify testing interaction effects using structural equation modeling. An illustrative application examines the interactive effect of perceptions of competence and perceptions of autonomy on exercise-intrinsic motivation. (SLD)

  20. Effects of Fluid-Structure Interaction on Dynamic Response of Composite Structures: Experimental and Numerical Studies

    DTIC Science & Technology

    2013-08-01

    composite structures in water and air to enhance the understanding of the effects of fluid-structure interaction on marine composite structural...naval structures are in continuous contact with a water medium. As a result, proper understanding of fluid-structure interaction is important for a...Fluid-Structure Interaction (FSI) is more critical for the former structures. The objective of this study was to investigate the effect of water on

  1. Structure factors in granular experiments with homogeneous fluidization.

    PubMed

    Puglisi, Andrea; Gnoli, Andrea; Gradenigo, Giacomo; Sarracino, Alessandro; Villamaina, Dario

    2012-01-07

    Velocity and density structure factors are measured over a hydrodynamic range of scales in a horizontal quasi-2D fluidized granular experiment, with packing fractions φ ∈ [10%, 40%]. The fluidization is realized by vertically vibrating a rough plate, on top of which particles perform a Brownian-like horizontal motion in addition to inelastic collisions. On one hand, the density structure factor is equal to that of elastic hard spheres, except in the limit of large length-scales, as it occurs in the presence of an effective interaction. On the other hand, the velocity field shows a more complex structure which is a genuine expression of a non-equilibrium steady state and which can be compared to a recent fluctuating hydrodynamic theory with non-equilibrium noise. The temporal decay of velocity modes autocorrelations is compatible with linear hydrodynamic equations with rates dictated by viscous momentum diffusion, corrected by a typical interaction time with the thermostat. Equal-time velocity structure factors display a peculiar shape with a plateau at large length-scales and another one at small scales, marking two different temperatures: the "bath" temperature T(b), depending on shaking parameters, and the "granular" temperature T(g) < T(b), which is affected by collisions. The two ranges of scales are separated by a correlation length which grows with φ, after proper rescaling with the mean free path.

  2. The Dynamic Reactance Interaction - How Vested Interests Affect People's Experience, Behavior, and Cognition in Social Interactions.

    PubMed

    Steindl, Christina; Jonas, Eva

    2015-01-01

    In social interactions, individuals may sometimes pursue their own interests at the expense of their interaction partner. Such self-interested behaviors impose a threat to the interaction partner's freedom to act. The current article investigates this threat in the context of interdependence and reactance theory. We explore how vested interests influence reactance process stages of an advisor-client interaction. We aim to explore the interactional process that evolves. In two studies, participants took the perspective of a doctor (advisor) or a patient (client). In both studies we incorporated a vested interest. In Study 1 (N = 82) we found that in response to a vested interest of their interaction partner, patients indicated a stronger experience of reactance, more aggressive behavioral intentions, and more biased cognitions than doctors. A serial multiple mediation revealed that a vested interest engendered mistrust toward the interaction partner and this mistrust led to an emerging reactance process. Study 2 (N = 207) further demonstrated that doctors expressed their reactance in a subtle way: they revealed a classic confirmation bias when searching for additional information on their preliminary decision preference, indicating stronger defense motivation. We discuss how these findings can help us to understand how social interactions develop dynamically.

  3. Control Of Flexible Structures-2 (COFS-2) flight control, structure and gimbal system interaction study

    NASA Technical Reports Server (NTRS)

    Fay, Stanley; Gates, Stephen; Henderson, Timothy; Sackett, Lester; Kirchwey, Kim; Stoddard, Isaac; Storch, Joel

    1988-01-01

    The second Control Of Flexible Structures Flight Experiment (COFS-2) includes a long mast as in the first flight experiment, but with the Langley 15-m hoop column antenna attached via a gimbal system to the top of the mast. The mast is to be mounted in the Space Shuttle cargo bay. The servo-driven gimbal system could be used to point the antenna relative to the mast. The dynamic interaction of the Shuttle Orbiter/COFS-2 system with the Orbiter on-orbit Flight Control System (FCS) and the gimbal pointing control system has been studied using analysis and simulation. The Orbiter pointing requirements have been assessed for their impact on allowable free drift time for COFS experiments. Three fixed antenna configurations were investigated. Also simulated was Orbiter attitude control behavior with active vernier jets during antenna slewing. The effect of experiment mast dampers was included. Control system stability and performance and loads on various portions of the COFS-2 structure were investigated. The study indicates possible undesirable interaction between the Orbiter FCS and the flexible, articulated COFS-2 mast/antenna system, even when restricted to vernier reaction jets.

  4. Perceptions and experiences of people with mental illness regarding their interactions with police.

    PubMed

    Livingston, James D; Desmarais, Sarah L; Verdun-Jones, Simon; Parent, Richard; Michalak, Erin; Brink, Johann

    2014-01-01

    This study examined the perceptions and lived experiences of people with mental illness in relation to their interactions with the police. A community-based participatory research approach was used and a procedural justice theoretical perspective guided the study. In-depth, semi-structured interviews were conducted by peer researchers with 60 people with mental illness who had interacted with the police and were living in Metro Vancouver, Canada. Among the study participants, contact with the police was frequent and occurred under a diverse range of circumstances. The majority of participants perceived being treated in a procedurally just manner by the police officer(s) who were involved in their most recent interaction. Almost three-quarters (n=43, 72%) of participants were generally satisfied with how the police officer(s) had handled their most recent interaction. The slight majority of participants (n=30, 51%) rated their previous contacts with the police as a positive experience overall, with 32% (n=19) indicating that their previous interactions with the police were negative life experiences. The findings paint a more balanced picture than that which is often portrayed by the media. Emphasizing a procedural justice framework for police handling of situations involving people with mental illness is a vital step toward improving how these interactions are experienced and perceived.

  5. The FIRST experiment: interaction region and MAPS vertex detector

    NASA Astrophysics Data System (ADS)

    Spiriti, E.; de Napoli, M.; Romano, F.; FIRST Collaboration

    2011-06-01

    The improvement of the precision of the measurement of the nuclear cross-section, in order to fulfill the requirements of the actual Monte Carlo simulations for hadrontherapy and space radioprotection, is the main goal of the FIRST experiment. After a brief introduction on the treatment planning in hadrontherapy, this paper describes main characteristics and components of the experiment. The features of the interaction region detectors and their main needs (low material budget, high angular coverage, two tracks resolution and large trigger rate) are discussed. Special emphasis is devoted in discussing the new silicon pixel vertex detector, in particular its new developed data acquisition and its characterization with the first test results obtained with a prototype of the detector.

  6. Exploring novel structures for manipulating relativistic laser-plasma interaction

    NASA Astrophysics Data System (ADS)

    Ji, Liangliang

    2016-10-01

    The prospect of realizing compact particle accelerators and x-ray sources based on high power lasers has gained numerous attention. Utilization of all the proposed schemes in the field requires the laser-matter-interaction process to be repeatable or moreover, controllable. This has been very challenging at ultra-high light intensities due to the pre-pulse issue and the limitation on target manufacturing. With recent development on pulse cleaning technique, such as XPW and the use of plasma mirror, we now propose a novel approach that leverages recent advancements in 3D nano-printing of materials and high contrast lasers to manipulate the laser-matter interactions on the micro-scales. The current 3D direct laser-writing (DLW) technique can produce repeatable structures with at a resolution as high as 100 nm. Based on 3D PIC simulations, we explored two typical structures, the micro-cylinder and micro-tube targets. The former serves to enhance and control laser-electron acceleration and the latter is dedicated to manipulate relativistic light intensity. First principle-of-proof experiments were carried out in the SCARLET laser facility and confirmed some of our predictions on enhancing direct laser acceleration of electrons and ion acceleration. We believe that the use of the micro-structured elements provides another degree of freedom in LPI and these new results will open new paths towards micro-engineering interaction process that will benefit high field science, laser-based proton therapy, near-QED physics, and relativistic nonlinear optics. This work is supported by the AFOSR Basic Research Initiative (FA9550-14-1-0085).

  7. Recent Results from CLAS on Baryon Structure and Interactions

    SciTech Connect

    Ilieva, Yordanka Yordanova

    2013-08-01

    The understanding of baryon structure and interactions from Quantum Chromodynamics is one of the main objectives of modern hadron physics. Of particular interest is the regime of confinement where perturbative methods are not applicable to derive testable predictions. Understanding the transition from hadronic to partonic degrees of freedom, the hyperon-nucleon interaction, and nuclei in terms of quarks and gluons are some of the key problems. Here we present results of photoproduction experiments on light nuclear targets from Jefferson Lab Hall B. Our observation of onset of dimensional scaling in the cross section of two-body photodisintegration of (3)He at energy and momentum transfer well below 1 GeV suggests that quarks and gluons may be relevant degrees of freedom for the description of nuclear dynamics at energies lower than previously considered. Our program to study lambda-nucleon scattering via a large set of polarization observables for final-state interactions in exclusive hyperon photoproduction off the deuteron has produced preliminary results for single-polarization observables. The beam-spin asymmetry shows interesting features at large lambda polar angles and large kaon momenta.

  8. Quantifying long-range correlations and 1/f patterns in a minimal experiment of social interaction.

    PubMed

    Bedia, Manuel G; Aguilera, Miguel; Gómez, Tomás; Larrode, David G; Seron, Francisco

    2014-01-01

    In recent years, researchers in social cognition have found the "perceptual crossing paradigm" to be both a theoretical and practical advance toward meeting particular challenges. This paradigm has been used to analyze the type of interactive processes that emerge in minimal interactions and it has allowed progress toward understanding of the principles of social cognition processes. In this paper, we analyze whether some critical aspects of these interactions could not have been observed by previous studies. We consider alternative indicators that could complete, or even lead us to rethink, the current interpretation of the results obtained from both experimental and simulated modeling in the fields of social interactions and minimal perceptual crossing. In particular, we discuss the possibility that previous experiments have been analytically constrained to a short-term dynamic type of player response. Additionally, we propose the possibility of considering these experiments from a more suitable framework based on the use and analysis of long-range correlations and fractal dynamics. We will also reveal evidence supporting the idea that social interactions are deployed along many scales of activity. Specifically, we propose that the fractal structure of the interactions could be a more adequate framework to understand the type of social interaction patterns generated in a social engagement.

  9. Quantifying long-range correlations and 1/f patterns in a minimal experiment of social interaction

    PubMed Central

    Bedia, Manuel G.; Aguilera, Miguel; Gómez, Tomás; Larrode, David G.; Seron, Francisco

    2014-01-01

    In recent years, researchers in social cognition have found the “perceptual crossing paradigm” to be both a theoretical and practical advance toward meeting particular challenges. This paradigm has been used to analyze the type of interactive processes that emerge in minimal interactions and it has allowed progress toward understanding of the principles of social cognition processes. In this paper, we analyze whether some critical aspects of these interactions could not have been observed by previous studies. We consider alternative indicators that could complete, or even lead us to rethink, the current interpretation of the results obtained from both experimental and simulated modeling in the fields of social interactions and minimal perceptual crossing. In particular, we discuss the possibility that previous experiments have been analytically constrained to a short-term dynamic type of player response. Additionally, we propose the possibility of considering these experiments from a more suitable framework based on the use and analysis of long-range correlations and fractal dynamics. We will also reveal evidence supporting the idea that social interactions are deployed along many scales of activity. Specifically, we propose that the fractal structure of the interactions could be a more adequate framework to understand the type of social interaction patterns generated in a social engagement. PMID:25429277

  10. Police officers’ experiences of supportive and unsupportive social interactions following traumatic incidents

    PubMed Central

    Evans, Rachel; Pistrang, Nancy; Billings, Jo

    2013-01-01

    Background Police officers are routinely exposed to potentially traumatic incidents yet the majority do not develop post-traumatic stress disorder (PTSD). Social support has been identified as one factor that may maintain wellbeing in this population, although what constitutes supportive or unsupportive interactions is unclear. Objective To explore police officers’ experiences of supportive and unsupportive interactions following distressing incidents. Method Semi-structured interviews were conducted with 19 police officers. Transcripts were analysed using Braun and Clarke's (2006) thematic analysis approach. Results Participants described a range of supportive interactions with colleagues, friends, and family, as well as social constraints that hindered interactions. Ambivalence about talking about the impact of distressing events was striking throughout the accounts. The context and source of available support, as well as beliefs about talking, influenced their interactions. Humour was a central feature of interactions with colleagues; more emotional talk occurred with partners and close family, albeit with officers limiting details in order to protect others. Conclusions The findings provide tentative insights into the processes of social support that may contribute to the resilience of police officers following traumatic incidents. Further research is needed to examine whether the experiences of supportive and unsupportive interactions differ for those with and without PTSD. PMID:23516046

  11. Structure and ubiquitin binding of the ubiquitin-interacting motif

    SciTech Connect

    Fisher,R.; Wang, B.; Alam, S.; Higginson, D.; Robinson, H.; Sundquist, C.; Hill, C.

    2003-01-01

    Ubiquitylation is used to target proteins into a large number of different biological processes including proteasomal degradation, endocytosis, virus budding, and vacuolar protein sorting (Vps). Ubiquitylated proteins are typically recognized using one of several different conserved ubiquitin binding modules. Here, we report the crystal structure and ubiquitin binding properties of one such module, the ubiquitin-interacting motif (UIM). We found that UIM peptides from several proteins involved in endocytosis and vacuolar protein sorting including Hrs, Vps27p, Stam1, and Eps15 bound specifically, but with modest affinity (K{sub d} = 0.1-1 mM), to free ubiquitin. Full affinity ubiquitin binding required the presence of conserved acidic patches at the N and C terminus of the UIM, as well as highly conserved central alanine and serine residues. NMR chemical shift perturbation mapping experiments demonstrated that all of these UIM peptides bind to the I44 surface of ubiquitin. The 1.45 {angstrom} resolution crystal structure of the second yeast Vps27p UIM (Vps27p-2) revealed that the ubiquitin-interacting motif forms an amphipathic helix. Although Vps27p-2 is monomeric in solution, the motif unexpectedly crystallized as an antiparallel four-helix bundle, and the potential biological implications of UIM oligomerization are therefore discussed.

  12. Experiments Evaluating the Interaction between Deformable Substrates and Prograding Clinoforms

    NASA Astrophysics Data System (ADS)

    Chatmas, E. S.; Foreman, B.; Abeyta, A.; Paola, C.

    2013-12-01

    Passive margins often contain salt and mobile shale layers that act as deformable substrates underlying coastal sediments. By understanding the interaction between deformable substrates and migrating clinoforms in simplified, experimental settings, we hope to clarify their fundamental behavior in natural deltaic settings. Substrate deformation occurs by a number of processes and can result in rugose ocean floor bathymetry which can locally trap sediment. In our experiments, we focus on how differential sediment loading on two substrates of different rheologies (Newtonian versus Bingham) affects aspects of clinoform deposition. We are particularly interested in the effects of the progradation rate and substrate rheology on the locus of clinoform deposition over time as the substrate and delta interact. Our experimental setup uses a rectangular flume that is 230 cm long, 8 cm wide and 30 cm tall. The materials we used for the mobile shale experiments involved a mixture of kaolinite and water which provide a Bingham rheology, and the sediment was a quartz sand and coal mixture. For a Newtonian rheology we used corn syrup as a deformable substrate, capturing the Newtonian rheology of subsurface salt, and the sediment consisted of a mixture of equal volumes of walnut shells and kaolinite clay. For each experiment we systematically changed sediment feed rate and substrate thickness. Deformation styles differ qualitatively between Bingham (kaolinite/mobile shale) and Newtonian (corn syrup/salt) experiments. In mobile-shale (Bingham) experiments, a bulge forms at the toe of the clinoform and the clinoform eventually overtops this bulge, creating alternating thick and thin stratigraphic accumulations down depositional dip. For the salt (Newtonian) experiments, deformation occurs behind the clinoform foreset in the form of diapirs. Preliminary results show minimal impacts on shoreline progradation rate as the delta loads mobile shale substrates. This suggests that the

  13. NASA/DOD Control/Structures Interaction Technology, 1986

    NASA Technical Reports Server (NTRS)

    Wright, Robert L. (Compiler)

    1986-01-01

    Control/structures interactions, deployment dynamics and system performance of large flexible spacecraft are discussed. Spacecraft active controls, deployable truss structures, deployable antennas, solar power systems for space stations, pointing control systems for space station gimballed payloads, computer-aided design for large space structures, and passive damping for flexible structures are among the topics covered.

  14. Structural study of surfactant-dependent interaction with protein

    SciTech Connect

    Mehan, Sumit; Aswal, Vinod K.; Kohlbrecher, Joachim

    2015-06-24

    Small-angle neutron scattering (SANS) has been used to study the complex structure of anionic BSA protein with three different (cationic DTAB, anionic SDS and non-ionic C12E10) surfactants. These systems form very different surfactant-dependent complexes. We show that the structure of protein-surfactant complex is initiated by the site-specific electrostatic interaction between the components, followed by the hydrophobic interaction at high surfactant concentrations. It is also found that hydrophobic interaction is preferred over the electrostatic interaction in deciding the resultant structure of protein-surfactant complexes.

  15. Market structure explained by pairwise interactions

    NASA Astrophysics Data System (ADS)

    Bury, Thomas

    2013-03-01

    Financial markets are a typical example of complex systems where interactions between constituents lead to many remarkable features. Here we give empirical evidence, by making as few assumptions as possible, that the market microstructure capturing almost all of the available information in the data of stock markets does not involve higher order than pairwise interactions. We give an economic interpretation of this pairwise model. We show that it accurately recovers the empirical correlation coefficients; thus the collective behaviors are quantitatively described by models that capture the observed pairwise correlations but no higher-order interactions. Furthermore, we show that an order-disorder transition occurs, as predicted by the pairwise model. Last, we make the link with the graph-theoretic description of stock markets recovering the non-random and scale-free topology, shrinking length during crashes and meaningful clustering features, as expected.

  16. Sensitivity of the T2HKK experiment to nonstandard interactions

    NASA Astrophysics Data System (ADS)

    Fukasawa, Shinya; Ghosh, Monojit; Yasuda, Osamu

    2017-03-01

    If the flavor-dependent nonstandard interactions (NSIs) in neutrino propagation exist, then the matter effect is modified, and the modification is parametrized by the dimensionless parameter ɛα β (α , β =e , μ , τ ). In this paper, we discuss the sensitivity of the T2HKK experiment, the possibility of which is now seriously discussed as a future extension of the T2K experiment, to such NSIs. On the assumption that ɛα μ=0 (α =e , μ , τ ) and ɛτ τ=|ɛe τ|/(1 +ɛe e), which are satisfied by other experiments to a good approximation, we find that, among the possible off-axis flux configurations of 1.3°, 1.5°, 2.0°, and 2.5°, the case of the off-axis angle 1.3° gives the highest sensitivity to ɛe e and |ɛe τ|. Our results show that the 1.3° off-axis configuration can exclude NSIs for |ɛe e|≳1 or |ɛe τ|≳0.2 at 3 σ . We also find that in the presence of NSIs T2HKK (for the off-axis angle 1.3°) has better sensitivity to the two C P phases [δC P and arg(ɛe τ)] than DUNE. This is because of the synergy between the two detectors, i.e., one in Kamioka and one in Korea. T2HKK has better sensitivity to the C P phases than the atmospheric neutrino experiment at Hyper-Kamiokande in inverted hierarchy, but in normal hierarchy, the atmospheric neutrino experiment has the best sensitivity to the C P phases.

  17. Experiments on Diffusion Flame Structure of a Laminar Vortex Ring

    NASA Technical Reports Server (NTRS)

    Chen, Shin-Juh; Dahm, Werner J. A.

    1999-01-01

    The study of flame-vortex interactions provides one of the means to better understand turbulent combustion, and allows for canonical configurations that contain the fundamental elements found in turbulent flames, These include concentrated vorticity, entrainment and mixing, strain and nonequilibrium phenomena, diffusion and differential diffusion, partial premixing and diluent effects, and heat release effects. In flame- vortex configurations, these fundamental elements can be studied under more controlled conditions than is possible in direct investigations of turbulent flames. Since the paper of Marble, the problem of the flame-vortex interaction has received considerable attention theoretically, numerically and experimentally. Several configurations exist for study of the premixed flame/vortex ring interaction but more limited results have been obtained to date for the diffusion flame/vortex ring case. The setup of Chen and Dahm, which is conceptually similar to that of Karagozian and Manda and Karagozian, Suganuma and Strom where the ring is composed of fuel and air and combustion begins during the ring formation process, is used in the current study. However, it is essential to conduct the experiments in microgravity to remove the asymmetries caused by buoyancy and thus obtain highly symmetric and repeatable interactions. In previous studies it was found that the flame structure of the vortex ring was similar to that obtained analytically by Karagozian and Manda. Dilution of propane with nitrogen led mainly to a reduction in flame luminosities, flame burnout times were affected by both fuel volumes and amount of dilution, and a simple model of the burnout times was developed. In this paper, a discussion on reacting ring displacement and flame burnout time will be given, and the flame structures of vortex rings containing ethane and air will be compared to those of propane reacting in air.

  18. New graduate nurses' experiences of interactions in the critical care unit.

    PubMed

    Saghafi, Farida; Hardy, Jennifer; Hillege, Sharon

    2012-08-01

    This paper reports on one of the key findings from a recent descriptive phenomenological study on lived experience of 10 new graduate nurses (NGNs) in an intensive care unit (ICU) in a major acute care hospital. Interpersonal relationships experienced by NGNs in ICU give rise to diverse thoughts, perceptions and feelings that may have significant impact on their professional development, job satisfaction and retention. The researcher conducted in-depth, semi-structured audio-taped interviews to collect the data. Interaction with others as key theme and related subthemes: interaction with patients; interaction with other members of the ICU team; who is approachable; and feedback emerged. The NGNs' perception of their ability to interact with others, as part of their professional development, is influenced by both (i) how they see themselves and (ii) how they perceive that others see them.

  19. Solving Fluid Structure Interaction Problems with an Immersed Boundary Method

    NASA Technical Reports Server (NTRS)

    Barad, Michael F.; Brehm, Christoph; Kiris, Cetin C.

    2016-01-01

    An immersed boundary method for the compressible Navier-Stokes equations can be used for moving boundary problems as well as fully coupled fluid-structure interaction is presented. The underlying Cartesian immersed boundary method of the Launch Ascent and Vehicle Aerodynamics (LAVA) framework, based on the locally stabilized immersed boundary method previously presented by the authors, is extended to account for unsteady boundary motion and coupled to linear and geometrically nonlinear structural finite element solvers. The approach is validated for moving boundary problems with prescribed body motion and fully coupled fluid structure interaction problems. Keywords: Immersed Boundary Method, Higher-Order Finite Difference Method, Fluid Structure Interaction.

  20. Neutron Interactions in the CUORE Neutrinoless Double Beta Decay Experiment

    SciTech Connect

    Dolinski, Michelle Jean

    2008-10-01

    Neutrinoless double beta decay (0vDBD) is a lepton-number violating process that can occur only for a massive Majorana neutrino. The search for 0vDBD is currently the only practical experimental way to determine whether neutrinos are identical to their own antiparticles (Majorana neutrinos) or have distinct particle and anti-particle states (Dirac neutrinos). In addition, the observation of 0vDBD can provide information about the absolute mass scale of the neutrino. The Cuoricino experiment was a sensitive search for 0vDBD, as well as a proof of principle for the next generation experiment, CUORE. CUORE will search for 0vDBD of 130Te with a ton-scale array of unenriched TeO2 bolometers. By increasing mass and decreasing the background for 0vDBD, the half-life sensitivity of CUORE will be a factor of twenty better than that of Cuoricino. The site for both of these experiments is the Laboratori Nazionali del Gran Sasso, an underground laboratory with 3300 meters water equivalent rock overburden and a cosmic ray muon attenuation factor of 10-6. Because of the extreme low background requirements for CUORE, it is important that all potential sources of background in the 0vDBD peak region at 2530 keV are well understood. One potential source of background for CUORE comes from neutrons, which can be produced underground both by (α,n) reactions and by fast cosmic ray muon interactions. Preliminary simulations by the CUORE collaboration indicate that these backgrounds will be negligible for CUORE. However, in order to accurately simulate the expected neutron background, it is important to understand the cross sections for neutron interactions with detector materials. In order to help refine these simulations, I have measured the gamma-ray production cross sections for interactions of neutrons on the abundant stable isotopes of Te using the GEANIE detector array at the Los Alamos Neutron Science Center. In addition, I have used the GEANIE

  1. Structural and functional bases of laser-microvessels interaction

    NASA Astrophysics Data System (ADS)

    Kozlov, Valentine I.; Terman, Oleg A.; Builin, Vitalij; Lebedeva, Natalia A.; Samoilov, Nickolai

    1993-07-01

    Structural and functional microcirculatory changes in tissues and organs (muscles, liver, derma, epinephros, brain cortex) under various dosages and powers of laser irradiation in the red (633 nm) and near infrared (890 nm) spectrum regions have been studied in experiments and clinic. In case of nonsensitized tissues the `photoactivation' range of power densities and doses of laser irradiation has been established. We have identified a short-term reaction of microvessels and a long-term reaction (adaptation). The former consists of intensification of microcirculation and metabolism rise in parenchymatous cells; the latter is connected with neoangiogenesis acceleration. The intensification of the blood microcirculation includes a dilation of microvessels of all orders, an amplification of arteriolar vasomotions and an opening of `reserved' capillaries. Data on the structural reconstruction of myocytes and endotheliocytes have shown that the high differential parenchymatous cells and its membrane structures are sensitive to low energy laser irradiation and, on the other hand, under low energy laser irradiation there is an activation of synthetic processes in the cells. Thus, during the laser-tissue interaction in such complex system as human organism the microcirculation plays the key role among the other systems.

  2. Fluid-structure interactions in compressible cavity flows

    DOE PAGES

    Wagner, Justin L.; Casper, Katya Marie; Beresh, Steven J.; ...

    2015-06-08

    Experiments were performed to understand the complex fluid-structure interactions that occur during aircraft internal store carriage. A cylindrical store was installed in a rectangular cavity having a length-to-depth ratio of 3.33 and a length-to-width ratio of 1. The Mach number ranged from 0.6 to 2.5 and the incoming boundary layer was turbulent. Fast-response pressure measurements provided aeroacoustic loading in the cavity, while triaxial accelerometers provided simultaneous store response. Despite occupying only 6% of the cavity volume, the store significantly altered the cavity acoustics. The store responded to the cavity flow at its natural structural frequencies, and it exhibited a directionallymore » dependent response to cavity resonance. Specifically, cavity tones excited the store in the streamwise and wall-normal directions consistently, whereas a spanwise response was observed only occasionally. Also, the streamwise and wall-normal responses were attributed to the longitudinal pressure waves and shear layer vortices known to occur during cavity resonance. Although the spanwise response to cavity tones was limited, broadband pressure fluctuations resulted in significant spanwise accelerations at store natural frequencies. As a result, the largest vibrations occurred when a cavity tone matched a structural natural frequency, although energy was transferred more efficiently to natural frequencies having predominantly streamwise and wall-normal motions.« less

  3. Fluid-structure interactions in compressible cavity flows

    SciTech Connect

    Wagner, Justin L.; Casper, Katya Marie; Beresh, Steven J.; Hunter, Patrick S.; Spillers, Russell Wayne; Henfling, John F.; Mayes, Randall L.

    2015-06-08

    Experiments were performed to understand the complex fluid-structure interactions that occur during aircraft internal store carriage. A cylindrical store was installed in a rectangular cavity having a length-to-depth ratio of 3.33 and a length-to-width ratio of 1. The Mach number ranged from 0.6 to 2.5 and the incoming boundary layer was turbulent. Fast-response pressure measurements provided aeroacoustic loading in the cavity, while triaxial accelerometers provided simultaneous store response. Despite occupying only 6% of the cavity volume, the store significantly altered the cavity acoustics. The store responded to the cavity flow at its natural structural frequencies, and it exhibited a directionally dependent response to cavity resonance. Specifically, cavity tones excited the store in the streamwise and wall-normal directions consistently, whereas a spanwise response was observed only occasionally. Also, the streamwise and wall-normal responses were attributed to the longitudinal pressure waves and shear layer vortices known to occur during cavity resonance. Although the spanwise response to cavity tones was limited, broadband pressure fluctuations resulted in significant spanwise accelerations at store natural frequencies. As a result, the largest vibrations occurred when a cavity tone matched a structural natural frequency, although energy was transferred more efficiently to natural frequencies having predominantly streamwise and wall-normal motions.

  4. A Virtual Rock Physics Laboratory Through Visualized and Interactive Experiments

    NASA Astrophysics Data System (ADS)

    Vanorio, T.; Di Bonito, C.; Clark, A. C.

    2014-12-01

    As new scientific challenges demand more comprehensive and multidisciplinary investigations, laboratory experiments are not expected to become simpler and/or faster. Experimental investigation is an indispensable element of scientific inquiry and must play a central role in the way current and future generations of scientist make decisions. To turn the complexity of laboratory work (and that of rocks!) into dexterity, engagement, and expanded learning opportunities, we are building an interactive, virtual laboratory reproducing in form and function the Stanford Rock Physics Laboratory, at Stanford University. The objective is to combine lectures on laboratory techniques and an online repository of visualized experiments consisting of interactive, 3-D renderings of equipment used to measure properties central to the study of rock physics (e.g., how to saturate rocks, how to measure porosity, permeability, and elastic wave velocity). We use a game creation system together with 3-D computer graphics, and a narrative voice to guide the user through the different phases of the experimental protocol. The main advantage gained in employing computer graphics over video footage is that students can virtually open the instrument, single out its components, and assemble it. Most importantly, it helps describe the processes occurring within the rock. These latter cannot be tracked while simply recording the physical experiment, but computer animation can efficiently illustrate what happens inside rock samples (e.g., describing acoustic waves, and/or fluid flow through a porous rock under pressure within an opaque core-holder - Figure 1). The repository of visualized experiments will complement lectures on laboratory techniques and constitute an on-line course offered through the EdX platform at Stanford. This will provide a virtual laboratory for anyone, anywhere to facilitate teaching/learning of introductory laboratory classes in Geophysics and expand the number of courses

  5. Interface structure of co-rotating interaction regions

    NASA Technical Reports Server (NTRS)

    Ogilvie, K. W.; Roelof, E. C.; Forsyth, R. J.

    1997-01-01

    Plasma and particle observations on Ulysses during its passes through the southern and northern heliosphere have revealed that, inside the streamer belt, the large-scale structure of the quiet global heliosphere is dominated by corotating interaction regions (CIRs). Therefore, considerable attention is now being given to the internal plasma structure of CIRs, and in particular, to the manifestations of the stream interfaces that should mark their origins as interactions between low speed solar wind (in the low-latitude streamer belt) and high speed solar wind (from the equatorial extensions of the high latitude polar coronal holes). The SWICS and HI-SCALE experiments on Ulysses combine plasma and energetic particle measurements that are of considerable utility for such studies because, between them, they cover the proton energy range from 10 eV to 5 MeV. These measurements are used, together with magnetic field data, to study the remarkable series of CIRs that occurred during the period beginning July 1992 and the end of 1993 as Ulysses rose from the ecliptic to a southern heliographic latitude of 48 deg. The structure of the regions between the forward and reverse shocks were previously analyzed in terms of the proton specific entropy argument log that should exhibit a discontinuous jump at the stream interface. It was claimed that the stream interface, defined with respect to specific entropy, is also associated with a discontinuity in energetic proton intensities. The energetic particle data (greater than 60 keV) and how they were ordered with respect to interfaces and with respect to the magnetic field were examined.

  6. Controller-structure interaction compensation using adaptive residual mode filters

    NASA Technical Reports Server (NTRS)

    Davidson, Roger A.; Balas, Mark J.

    1990-01-01

    It is not feasible to construct controllers for large space structures or large scale systems (LSS's) which are of the same order as the structures. The complexity of the dynamics of these systems is such that full knowledge of its behavior cannot by processed by today's controller design methods. The controller for system performance of such a system is therefore based on a much smaller reduced-order model (ROM). Unfortunately, the interaction between the LSS and the ROM-based controller can produce instabilities in the closed-loop system due to the unmodeled dynamics of the LSS. Residual mode filters (RMF's) allow the systematic removal of these instabilities in a matter which does not require a redesign of the controller. In addition RMF's have a strong theoretical basis. As simple first- or second-order filters, the RMF CSI compensation technique is at once modular, simple and highly effective. RMF compensation requires knowledge of the dynamics of the system modes which resulted in the previous closed-loop instabilities (the residual modes), but this information is sometimes known imperfectly. An adaptive, self-tuning RMF design, which compensates for uncertainty in the frequency of the residual mode, has been simulated using continuous-time and discrete-time models of a flexible robot manipulator. Work has also been completed on the discrete-time experimental implementation on the Martin Marietta flexible robot manipulator experiment. This paper will present the results of that work on adaptive, self-tuning RMF's, and will clearly show the advantage of this adaptive compensation technique for controller-structure interaction (CSI) instabilities in actively-controlled LSS's.

  7. Antagonistic interactions of soil pseudomonads are structured in time.

    PubMed

    Kraemer, Susanne A; Soucy, Jean-Paul R; Kassen, Rees

    2017-04-06

    Social interactions have been invoked as potential major selective forces structuring natural microbial communities and thus may help explain the astonishing bacterial diversity of natural ecosystems. Here, we investigate the prevalence and structure of exotoxin-mediated antagonistic interactions among free-living soil Pseudomonas strains collected over the course of two years at distances of up to one kilometer. Unlike some previous studies on antagonistic interactions among natural isolates, we found the prevalence of exotoxin-mediated inhibitions to be relatively low. When present, antagonistic interactions show a weakly negative relationship with genetic relatedness and metabolic similarity. Intriguingly, isolates sampled from the same growing season were significantly more likely to inhibit each other than they were to inhibit isolates from different growing seasons. Exotoxin-mediated antagonistic interactions between soil pseudomonads thus seem to be structured in time but do not appear to be a major selective force structuring free-living soil bacterial communities of soil pseudomonads.

  8. ePsych: interactive demonstrations and experiments in psychology.

    PubMed

    Bradshaw, Gary L; Steinman, Bernard; McCarley, Nancy

    2002-05-01

    ePsych (http://epsych.msstate.edu), a new Web site currently under active development, is intended to teach students about the discipline of psychology. The site presumes little prior knowledge about the field and so may be used in introductory classes, but it incorporates sufficient depth of coverage to be useful in more advanced classes as well. Numerous interactive and dynamic elements are incorporated into various modules, orientations, and guidebooks. These elements include Java-based experiments and demonstrations, video clips, and animated diagrams. Rapid access to all material is provided through a layer-based navigation system that allows users to visit various "Worlds of the Mind." Active learning is encouraged, by challenging students with puzzles and problems and by providing the opportunity to "dig deeper" to learn more about the phenomena at hand.

  9. Real time digital control and controlled structures experiments

    NASA Technical Reports Server (NTRS)

    Rossi, Michael J.; Knowles, Gareth J.; Rauch, Frank

    1991-01-01

    Viewgraphs covering the following topics are given: controlled structures technology at Grumman Corporate Research Center, active and passive control technology, experiment plans, and vacuum chamber test experiment objectives and setup.

  10. Fluid Structure Interaction in a Turbine Blade

    NASA Technical Reports Server (NTRS)

    Gorla, Rama S. R.

    2004-01-01

    An unsteady, three dimensional Navier-Stokes solution in rotating frame formulation for turbomachinery applications is presented. Casting the governing equations in a rotating frame enabled the freezing of grid motion and resulted in substantial savings in computer time. The turbine blade was computationally simulated and probabilistically evaluated in view of several uncertainties in the aerodynamic, structural, material and thermal variables that govern the turbine blade. The interconnection between the computational fluid dynamics code and finite element structural analysis code was necessary to couple the thermal profiles with the structural design. The stresses and their variations were evaluated at critical points on the Turbine blade. Cumulative distribution functions and sensitivity factors were computed for stress responses due to aerodynamic, geometric, mechanical and thermal random variables.

  11. Interactive visualization tools for the structural biologist.

    PubMed

    Porebski, Benjamin T; Ho, Bosco K; Buckle, Ashley M

    2013-10-01

    In structural biology, management of a large number of Protein Data Bank (PDB) files and raw X-ray diffraction images often presents a major organizational problem. Existing software packages that manipulate these file types were not designed for these kinds of file-management tasks. This is typically encountered when browsing through a folder of hundreds of X-ray images, with the aim of rapidly inspecting the diffraction quality of a data set. To solve this problem, a useful functionality of the Macintosh operating system (OSX) has been exploited that allows custom visualization plugins to be attached to certain file types. Software plugins have been developed for diffraction images and PDB files, which in many scenarios can save considerable time and effort. The direct visualization of diffraction images and PDB structures in the file browser can be used to identify key files of interest simply by scrolling through a list of files.

  12. Interactive visualization tools for the structural biologist

    PubMed Central

    Porebski, Benjamin T.; Ho, Bosco K.; Buckle, Ashley M.

    2013-01-01

    In structural biology, management of a large number of Protein Data Bank (PDB) files and raw X-ray diffraction images often presents a major organizational problem. Existing software packages that manipulate these file types were not designed for these kinds of file-management tasks. This is typically encountered when browsing through a folder of hundreds of X-ray images, with the aim of rapidly inspecting the diffraction quality of a data set. To solve this problem, a useful functionality of the Macintosh operating system (OSX) has been exploited that allows custom visualization plugins to be attached to certain file types. Software plugins have been developed for diffraction images and PDB files, which in many scenarios can save considerable time and effort. The direct visualization of diffraction images and PDB structures in the file browser can be used to identify key files of interest simply by scrolling through a list of files. PMID:24068844

  13. Ecological Networks: Structure, Interaction Strength, and Stability

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Samit; Sinha, Somdatta

    The fundamental building blocks of any ecosystem, the food webs, which are assemblages of species through various interconnections, provide a central concept in ecology. The study of a food web allows abstractions of the complexity and interconnectedness of natural communities that transcend the specific details of the underlying systems. For example, Fig. 1 shows a typical food web, where the species are connected through their feeding relationships. The top predator, Heliaster (starfish) feeds on many gastropods like Hexaplex, Morula, Cantharus, etc., some of whom predate on each other [129]. Interactions between species in a food web can be of many types, such as predation, competition, mutualism, commensalism, and ammensalism (see Section 1.1, Fig. 2).

  14. Temporal coherence structure rapidly shapes neuronal interactions

    PubMed Central

    Lu, Kai; Xu, Yanbo; Yin, Pingbo; Oxenham, Andrew J.; Fritz, Jonathan B.; Shamma, Shihab A.

    2017-01-01

    Perception of segregated sources is essential in navigating cluttered acoustic environments. A basic mechanism to implement this process is the temporal coherence principle. It postulates that a signal is perceived as emitted from a single source only when all of its features are temporally modulated coherently, causing them to bind perceptually. Here we report on neural correlates of this process as rapidly reshaped interactions in primary auditory cortex, measured in three different ways: as changes in response rates, as adaptations of spectrotemporal receptive fields following stimulation by temporally coherent and incoherent tone sequences, and as changes in spiking correlations during the tone sequences. Responses, sensitivity and presumed connectivity were rapidly enhanced by synchronous stimuli, and suppressed by alternating (asynchronous) sounds, but only when the animals engaged in task performance and were attentive to the stimuli. Temporal coherence and attention are therefore both important factors in auditory scene analysis. PMID:28054545

  15. Operational experience with VAWT blades. [structural performance

    NASA Technical Reports Server (NTRS)

    Sullivan, W. N.

    1979-01-01

    The structural performance of 17 meter diameter wind turbine rotors is discussed. Test results for typical steady and vibratory stress measurements are summarized along with predicted values of stress based on a quasi-static finite element model.

  16. Interaction of almond cystatin with pesticides: Structural and functional analysis.

    PubMed

    Siddiqui, Azad Alam; Khaki, Peerzada Shariq Shaheen; Bano, Bilqees

    2017-03-01

    Pesticides are chemical substances that eliminate or control a variety of agricultural pests that damage crops and livestock. They not only affect the targeted pests but also affect the nontargeted systems, raising more concerns for their effect on both plant and animal systems. Cystatins (cysteine protease inhibitor) are ubiquitously present in all living cells and show a variety of important physiological functions. The present study shows the effect of different pesticides (pendimethalin, methoxyfenozide, and Cu(II) hydroxide) on purified almond cystatin. Almond cystatin showed concentration-dependent loss in papain inhibitory activity on interaction with the pesticides, showing maximum loss in the presence of Cu(II) hydroxide and minimum in the case of methoxyfenozide. Native polyacrylamide gel electrophoresis showed maximum degradation of purified cystatin in the presence of Cu(II) hydroxide with insignificant effect in the presence of methoxyfenozide. Structural alterations were significant in the case of Cu(II) hydroxide and less in the case of methoxyfenozide as revealed by UV and fluorescence spectral studies. Secondary structural alterations were further conformed by circular dichroism and Fourier transform infrared spectroscopy. The α-helix content of almond cystatin decreases from 35.64% (native) to 34.83%, 30.79%, and 29.62% for methoxyfenozide-, pendimethalin-, and Cu(II) hydroxide-treated cystatin, respectively. A Fourier transform infrared study shows an amide I band shift for almond cystatin from 1649.15 ± 0.5 to 1646.48 ± 0.6, 1640.44 ± 0.6, and 1635.11 ± 0.3 cm(-1) for methoxyfenozide, pendimethalin, and Cu(II) hydroxide, respectively. Values obtained for different thermodynamic parameters (ΔH(0) , ΔG(0) , N, and ΔS(0) ) by isothermal titration calorimetric experiments reveal maximum binding of almond cystatin with Cu(II) hydroxide followed by pendimethalin and little interaction with methoxyfenozide.

  17. Supersonic Parachute Aerodynamic Testing and Fluid Structure Interaction Simulation

    NASA Astrophysics Data System (ADS)

    Lingard, J. S.; Underwood, J. C.; Darley, M. G.; Marraffa, L.; Ferracina, L.

    2014-06-01

    The ESA Supersonic Parachute program expands the knowledge of parachute inflation and flying characteristics in supersonic flows using wind tunnel testing and fluid structure interaction to develop new inflation algorithms and aerodynamic databases.

  18. Space Technology Experiment Platform (STEP). A Shuttle-borne support facility for structures, structural dynamics, and control technology flight experiments

    NASA Technical Reports Server (NTRS)

    Harris, J. E.; Pinson, L. D.

    1983-01-01

    The Space Transportation System (STS) is used for technology experiments in space. The Space Technology Experiment Platform (STEP) is a Shuttle-borne experiment support facility for use by structures, structural dynamics, and controls technology flight experiments. STEP represents a key element in the commitment to STS utilization. The STEP concept and definition process is discussed, and the results obtained to date on the configuration and function capability are summarized, and preliminary schedule information is presented.

  19. Structure and thermodynamics of Drug-RNA aptamer interactions.

    PubMed

    Da Costa, J B; Dieckmann, T

    2013-04-01

    This mini-review will provide an overview on the recent studies of structure and thermodynamics of RNA aptamers that target drug molecules. These aptamers are studied to provide insight into RNA drug interactions. This interaction is important due to the many roles RNA plays in cell biology.

  20. Structuring Peer Interaction To Promote High-Level Cognitive Processing.

    ERIC Educational Resources Information Center

    King, Alison

    2002-01-01

    Examines the kind of peer learning that demands high-level cognitive processing, discussing how peer interaction influences cognitive processes (structuring peer interaction and using guided reciprocal peer questioning); how to promote cognitive processing (knowledge construction and integration and socio- cognitive conflict); metacognition; and…

  1. Controls structures interaction, an interdisciplinary challenge for large spacecraft

    NASA Technical Reports Server (NTRS)

    Hanks, Brantley R.

    1990-01-01

    Controls structures interaction (CSI), a phenomenon which occurs when control forces interact with the flexible motion of a structure, can, if improperly treated in design and development, cause reduced performance or control instabilities. Properly applied, it can improve flexible spacecraft performance. In this paper, the NASA CSI technology program for future spacecraft applications is described. The program objectives and organization are outlined, and the nature of individual program tasks is described. The interdisciplinary aspects of CSI are also addressed.

  2. Relaunch of the Interactive Plasma Physics Educational Experience (IPPEX)

    NASA Astrophysics Data System (ADS)

    Dominguez, A.; Rusaitis, L.; Zwicker, A.; Stotler, D. P.

    2015-11-01

    In the late 1990's PPPL's Science Education Department developed an innovative online site called the Interactive Plasma Physics Educational Experience (IPPEX). It featured (among other modules) two Java based applications which simulated tokamak physics: A steady state tokamak (SST) and a time dependent tokamak (TDT). The physics underlying the SST and the TDT are based on the ASPECT code which is a global power balance code developed to evaluate the performance of fusion reactor designs. We have relaunched the IPPEX site with updated modules and functionalities: The site itself is now dynamic on all platforms. The graphic design of the site has been modified to current standards. The virtual tokamak programming has been redone in Javascript, taking advantage of the speed and compactness of the code. The GUI of the tokamak has been completely redesigned, including more intuitive representations of changes in the plasma, e.g., particles moving along magnetic field lines. The use of GPU accelerated computation provides accurate and smooth visual representations of the plasma. We will present the current version of IPPEX as well near term plans of incorporating real time NSTX-U data into the simulation.

  3. Astronomy Patch Day: An Interactive Astronomy Experience for Girl Scouts

    NASA Astrophysics Data System (ADS)

    Knierman, K. A.; McCarthy, D. W.; Schutz, K.

    2005-12-01

    To help encourage a new generation of women in science, we have created Astronomy Patch Day for the Sahuaro Girl Scout Council in Tucson, Arizona. This all-day event is an interactive experience for Girl Scouts ages 5-18 to learn about astronomical concepts and women in astronomy. Our first Astronomy Patch Day, held on March 19, 2005, in conjunction with the Sahuaro Council's annual Science, Math, and Related Technologies (SMART) program, was very successful, reaching about 150-200 girls and their leaders. Individual troops rotated every half hour among our six activity booths: Earth-Moon, Solar System, Stars, Galaxies, Universe, and Ask an Astronomer, which were staffed by trained Girl Scout Leaders as well as faculty, post-doctoral researchers, and graduate students from Steward Observatory. To earn a patch, younger girls (ages 5-12) had to complete activities at three booths and older girls had to complete all six activities. Positive feedback for this event was received from both the girls and leaders. We plan to hold Astronomy Patch Day annually, possibly with different and/or additional activities in future years. K. Knierman is supported by an Arizona/NASA Space Grant Fellowship. This outreach program is supported by NIRCam/JWST E/PO.

  4. Aromatic-Aromatic Interactions in Biological System: Structure Activity Relationships

    SciTech Connect

    Rajagopal, Appavu; Deepa, Mohan; Govindaraju, Munisamy

    2016-02-26

    While, intramolecular hydrogen bonds have attracted the greatest attention in studies of peptide conformations, the recognition that several other weakly polar interactions may be important determinants of folded structure has been growing. Burley and Petsko provided a comprehensive overview of the importance of weakly polar interactions, in shaping protein structures. The interactions between aromatic rings, which are spatially approximate, have attracted special attention. A survey of the proximal aromatic residue pairs in proteins, allowed Burley and Petsko to suggest that, “phenyl ring centroids are separated by a preferential distance of between 4.5 and 7 Å, and dihedral angles approximately 90° are most common”.

  5. Different Strokes for Different Folks: Jung's Typology and Structured Experiences.

    ERIC Educational Resources Information Center

    Haber, Russell Alan

    1980-01-01

    Examined and compared the evaluations of students differentiated by Carl Jung's psychotypology when they were involved in either a session of nonverbal communication experiences or a session of fantasy experiences. Some of the Jungian psychological types preferred different structured experiences. (Author)

  6. Structural analysis of in silico mutant experiments of human inner-kinetochore structure.

    PubMed

    Henze, Richard; Huwald, Jan; Mostajo, Nelly; Dittrich, Peter; Ibrahim, Bashar

    2015-01-01

    Large multi-molecular complexes like the kinetochore are lacking of suitable methods to determine their spatial structure. Here, we use and evaluate a novel modeling approach that combines rule-bases reaction network models with spatial molecular geometries. In particular, we introduce a method that allows to study in silico the influence of single interactions (e.g. bonds) on the spatial organization of large multi-molecular complexes and apply this method to an extended model of the human inner-kinetochore. Our computational analysis method encompasses determination of bond frequency, geometrical distances, statistical moments, and inter-dependencies between bonds using mutual information. For the analysis we have extend our previously reported human inner-kinetochore model by adding 13 new protein interactions and three protein geometry details. The model is validated by comparing the results of in silico with reported in vitro single protein deletion experiments. Our studies revealed that most simulations mimic the in vitro behavior of the kinetochore complex as expected. To identify the most important bonds in this model, we have created 39 mutants in silico by selectively disabling single protein interactions. In a total of 11,800 simulation runs we have compared the resulting structures to the wild-type. In particular, this allowed us to identify the interaction Cenp-W-H3 and Cenp-S-Cenp-X as having the strongest influence on the inner-kinetochore's structure. We conclude that our approach can become a useful tool for the in silico dynamical study of large, multi-molecular complexes.

  7. Effect of ethanol on structures and interactions among globular proteins

    NASA Astrophysics Data System (ADS)

    Kundu, Sarathi; Aswal, V. K.; Kohlbrecher, J.

    2017-02-01

    Structures and interactions among globular proteins BSA and lysozyme are explored by small angle neutron scattering (SANS) technique at pD ≈ 7.0 by varying ethanol concentration. Interaction behaviours are also obtained in presence of monovalent salt (NaCl). SANS analysis shows that for both lower and higher BSA concentrations and in presence of NaCl, combination of intermediate-range repulsion and weak long-range attraction is responsible for the effective interaction behaviours with the variation of ethanol concentration. For lysozyme, interaction nature is same as BSA in absence of NaCl but in presence of NaCl, fractal structure factor explains the interaction behaviours.

  8. Structures-propulsion interactions and requirements. [large space structures

    NASA Technical Reports Server (NTRS)

    Coyner, J. V.

    1982-01-01

    The effects of low-thrust primary propulsion system characteristics on the mass, area, and orbit transfer characteristics of large space systems (LSS) were determined. Three general structural classes of LSS were considered, each with a broad range of diameters and nonstructural surface densities. While transferring the deployed structure from LEO and to GEO, an acceleration range of 0.02 to 0.1 g's was found to maximize deliverable payload based on structural mass impact. After propulsion system parametric analyses considering four propellant combinations produced values for available payload mass, length and volume, a thrust level range which maximizes deliverable LSS diameter was determined corresponding to a structure and propulsion vehicle. The engine start and/or shutdown thrust transients on the last orbit transfer (apogee) burn can impose transient loads which would be greater than the steady-state loads at the burnout acceleration. The effect of the engine thrust transients on the LSS was determined from the dynamic models upon which various engine ramps were imposed.

  9. Structural Dynamics and Control Interaction of Flexible Structures

    NASA Technical Reports Server (NTRS)

    Ryan, Robert S. (Editor); Scofield, Harold N. (Editor)

    1987-01-01

    A Workshop was held to promote technical exchange between the structural dynamic and control disciplines, foster joint technology, and provide a forum for discussing and focusing critical issues in the separate and combined areas. The workshop was closed by a panel meeting. Panel members' viewpoints and their responses to questions are included.

  10. The NASA controls-structures interaction technology program

    NASA Technical Reports Server (NTRS)

    Newsom, Jerry R.; Layman, W. E.; Waites, H. B.; Hayduk, R. J.

    1990-01-01

    The interaction between a flexible spacecraft structure and its control system is commonly referred to as controls-structures interaction (CSI). The CSI technology program is developing the capability and confidence to integrate the structure and control system, so as to avoid interactions that cause problems and to exploit interactions to increase spacecraft capability. A NASA program has been initiated to advance CSI technology to a point where it can be used in spacecraft design for future missions. The CSI technology program is a multicenter program utilizing the resources of the NASA Langley Research Center (LaRC), the NASA Marshall Space Flight Center (MSFC), and the NASA Jet Propulsion Laboratory (JPL). The purpose is to describe the current activities, results to date, and future activities of the NASA CSI technology program.

  11. Interactive Multidimensional Scaling of Cognitive Structure Underlying Person Perception

    ERIC Educational Resources Information Center

    Kehoe, Jerard; Reynolds, Thomas J.

    1977-01-01

    A computer-interactive multidimensional scaling program was used together with free response methods to represent and label dimensions of individual cognitive structure underlying persons' perceptions. The dimensional structures derived were predictive of semantic differential, paired comparison, and Repertory Grid Test triad judgments.…

  12. Membrane Structure: Lipid-Protein Interactions in Microsomal Membranes*

    PubMed Central

    Trump, Benjamin F.; Duttera, Sue M.; Byrne, William L.; Arstila, Antti U.

    1970-01-01

    The relationships of phospholipid to membrane structure and function were examined in hepatic microsomes. Findings indicate that normal microsomal membrane structure is dependent on lipid-protein interactions and that it correlates closely with glucose-6-phosphatase activity. Modification of most phospholipid with phospholipase-C is associated with widening of the membrane which can be reversed following readdition of phospholipid. Images PMID:4317915

  13. Connecting Protein Structure to Intermolecular Interactions: A Computer Modeling Laboratory

    ERIC Educational Resources Information Center

    Abualia, Mohammed; Schroeder, Lianne; Garcia, Megan; Daubenmire, Patrick L.; Wink, Donald J.; Clark, Ginevra A.

    2016-01-01

    An understanding of protein folding relies on a solid foundation of a number of critical chemical concepts, such as molecular structure, intra-/intermolecular interactions, and relating structure to function. Recent reports show that students struggle on all levels to achieve these understandings and use them in meaningful ways. Further, several…

  14. Interactive Hangman Teaches Amino Acid Structures and Abbreviations

    ERIC Educational Resources Information Center

    Pennington, Britney O.; Sears, Duane; Clegg, Dennis O.

    2014-01-01

    We developed an interactive exercise to teach students how to draw the structures of the 20 standard amino acids and to identify the one-letter abbreviations by modifying the familiar game of "Hangman." Amino acid structures were used to represent single letters throughout the game. To provide additional practice in identifying…

  15. Medium Modification of Hadronic Interactions from Low Energy Experiments

    NASA Astrophysics Data System (ADS)

    Friedman, E.

    Medium-modification of hadronic interactions is defined as the differences between hadron-hadron interaction in the nuclear medium and the corresponding interaction in free space. Deeply penetrating hadrons provide such information and we discuss here pionic atoms and scattering by nuclei of 21.5 MeV pions. Brief mention is made also of the interaction of 500-700 MeV/c K+ with nuclei.

  16. Evolutionary dynamics of general group interactions in structured populations

    NASA Astrophysics Data System (ADS)

    Li, Aming; Broom, Mark; Du, Jinming; Wang, Long

    2016-02-01

    The evolution of populations is influenced by many factors, and the simple classical models have been developed in a number of important ways. Both population structure and multiplayer interactions have been shown to significantly affect the evolution of important properties, such as the level of cooperation or of aggressive behavior. Here we combine these two key factors and develop the evolutionary dynamics of general group interactions in structured populations represented by regular graphs. The traditional linear and threshold public goods games are adopted as models to address the dynamics. We show that for linear group interactions, population structure can favor the evolution of cooperation compared to the well-mixed case, and we see that the more neighbors there are, the harder it is for cooperators to persist in structured populations. We further show that threshold group interactions could lead to the emergence of cooperation even in well-mixed populations. Here population structure sometimes inhibits cooperation for the threshold public goods game, where depending on the benefit to cost ratio, the outcomes are bistability or a monomorphic population of defectors or cooperators. Our results suggest, counterintuitively, that structured populations are not always beneficial for the evolution of cooperation for nonlinear group interactions.

  17. The role of nucleobase interactions in RNA structure and dynamics

    PubMed Central

    Bottaro, Sandro; Di Palma, Francesco; Bussi, Giovanni

    2014-01-01

    The intricate network of interactions observed in RNA three-dimensional structures is often described in terms of a multitude of geometrical properties, including helical parameters, base pairing/stacking, hydrogen bonding and backbone conformation. We show that a simple molecular representation consisting in one oriented bead per nucleotide can account for the fundamental structural properties of RNA. In this framework, canonical Watson-Crick, non-Watson-Crick base-pairing and base-stacking interactions can be unambiguously identified within a well-defined interaction shell. We validate this representation by performing two independent, complementary tests. First, we use it to construct a sequence-independent, knowledge-based scoring function for RNA structural prediction, which compares favorably to fully atomistic, state-of-the-art techniques. Second, we define a metric to measure deviation between RNA structures that directly reports on the differences in the base–base interaction network. The effectiveness of this metric is tested with respect to the ability to discriminate between structurally and kinetically distant RNA conformations, performing better compared to standard techniques. Taken together, our results suggest that this minimalist, nucleobase-centric representation captures the main interactions that are relevant for describing RNA structure and dynamics. PMID:25355509

  18. NASA/DOD Control/Structures Interaction Technology, 1986

    NASA Technical Reports Server (NTRS)

    Wright, Robert L. (Compiler)

    1987-01-01

    Papers presented at the CSI Technology Conference are given. The conference was jointly sponsored by the NASA Office of Aeronautics and Space Technology and the Department of Defense. The conference is the beginning of a series of annual conferences whose purpose is to report to industry, academia, and government agencies the current status of Control/Structures Interaction technology. The conference program was divided into five sessions: (1) Future spacecraft requirements; Technology issues and impact; (2) DOD special topics; (3) Large space systems technology; (4) Control of flexible structures, and (5) Selected NASA research in control structures interaction.

  19. JPL control/structure interaction test bed real-time control computer architecture

    NASA Technical Reports Server (NTRS)

    Briggs, Hugh C.

    1989-01-01

    The Control/Structure Interaction Program is a technology development program for spacecraft that exhibit interactions between the control system and structural dynamics. The program objectives include development and verification of new design concepts - such as active structure - and new tools - such as combined structure and control optimization algorithm - and their verification in ground and possibly flight test. A focus mission spacecraft was designed based upon a space interferometer and is the basis for design of the ground test article. The ground test bed objectives include verification of the spacecraft design concepts, the active structure elements and certain design tools such as the new combined structures and controls optimization tool. In anticipation of CSI technology flight experiments, the test bed control electronics must emulate the computation capacity and control architectures of space qualifiable systems as well as the command and control networks that will be used to connect investigators with the flight experiment hardware. The Test Bed facility electronics were functionally partitioned into three units: a laboratory data acquisition system for structural parameter identification and performance verification; an experiment supervisory computer to oversee the experiment, monitor the environmental parameters and perform data logging; and a multilevel real-time control computing system. The design of the Test Bed electronics is presented along with hardware and software component descriptions. The system should break new ground in experimental control electronics and is of interest to anyone working in the verification of control concepts for large structures.

  20. Social setting, intuition and experience in laboratory experiments interact to shape cooperative decision-making.

    PubMed

    Capraro, Valerio; Cococcioni, Giorgia

    2015-07-22

    Recent studies suggest that cooperative decision-making in one-shot interactions is a history-dependent dynamic process: promoting intuition versus deliberation typically has a positive effect on cooperation (dynamism) among people living in a cooperative setting and with no previous experience in economic games on cooperation (history dependence). Here, we report on a laboratory experiment exploring how these findings transfer to a non-cooperative setting. We find two major results: (i) promoting intuition versus deliberation has no effect on cooperative behaviour among inexperienced subjects living in a non-cooperative setting; (ii) experienced subjects cooperate more than inexperienced subjects, but only under time pressure. These results suggest that cooperation is a learning process, rather than an instinctive impulse or a self-controlled choice, and that experience operates primarily via the channel of intuition. Our findings shed further light on the cognitive basis of human cooperative decision-making and provide further support for the recently proposed social heuristics hypothesis.

  1. Recent experiences using finite-element-based structural optimization

    NASA Technical Reports Server (NTRS)

    Paul, B. K.; Mcconnell, J. C.; Love, Mike H.

    1989-01-01

    Structural optimization has been available to the structural analysis community as a tool for many years. The popular use of displacement method finite-element techniques to analyze linearly elastic structures has resulted in an ability to calculate the weight and constraint gradients inexpensively for numerical optimization of structures. Here, recent experiences in the investigation and use of structural optimization are discussed. In particular, experience with the commercially available ADS/NASOPT code is addressed. An overview of the ADS/NASOPT procedure and how it was implemented is given. Two example problems are also discussed.

  2. Computational modeling of RNA 3D structures and interactions.

    PubMed

    Dawson, Wayne K; Bujnicki, Janusz M

    2016-04-01

    RNA molecules have key functions in cellular processes beyond being carriers of protein-coding information. These functions are often dependent on the ability to form complex three-dimensional (3D) structures. However, experimental determination of RNA 3D structures is difficult, which has prompted the development of computational methods for structure prediction from sequence. Recent progress in 3D structure modeling of RNA and emerging approaches for predicting RNA interactions with ions, ligands and proteins have been stimulated by successes in protein 3D structure modeling.

  3. Unconventional interactions between water and heterocyclic nitrogens in protein structures.

    PubMed

    Stollar, Elliott J; Gelpí, Jose Luis; Velankar, Sameer; Golovin, Adel; Orozco, Modesto; Luisi, Ben F

    2004-10-01

    We report an unusual interaction in which a water molecule approaches the heterocyclic nitrogen of tryptophan and histidine along an axis that is roughly perpendicular to the aromatic plane of the side chain. The interaction is distinct from the well-known conventional aromatic hydrogen-bond, and it occurs at roughly the same frequency in protein structures. Calculations indicate that the water-indole interaction is favorable energetically, and we find several cases in which such contacts are conserved among structural orthologs. The indole-water interaction links side chains and peptide backbone in turn regions, connects the side chains in beta-sheets, and bridges secondary elements from different domains. We suggest that the water-indole interaction can be indirectly responsible for the quenching of tryptophan fluorescence that is observed in the folding of homeodomains and, possibly, many other proteins. We also observe a similar interaction between water and the imidazole nitrogens of the histidine side chain. Taken together, these observations suggest that the unconventional water-indole and water-imidazole interactions provide a small but favorable contribution to protein structures.

  4. THERMAL SHOCK ANALYSIS OF WINDOWS INTERACTING WITH ENERGETIC, FOCUSED BEAM OF THE BNL MUON TARGET EXPERIMENT.

    SciTech Connect

    SIMOS, N.; KIRK, H.; PRIGL, R.; BROWN, K.; MCDONALD, K.

    2001-06-18

    In this paper, issues associated with the interaction of a proton beam with windows designed for the muon targetry experiment E951 at BNL are explored. Specifically, a 24 GeV proton beam up to 16 TP per pulse and a pulse length of 100 ns is tightly focused (to 0.5 mm rms radius) on an experimental target. The need to maintain an enclosed environment around the target implies the use of beam windows that will survive the passage of the proton beam. The required beam parameters in such a setting will induce very high thermal, quasi-static and shock stresses in the window structure that exceed the strength of most common materials. In this effort, a detailed analysis of the thermal/shock response of beam windows is attempted through a transient thermal and stress wave propagation formulation that incorporates energy deposition rates calculated the by hadron interaction code MARS. The thermal response of the window structure and the subsequent stress wave generation and propagation are computed using the finite element analysis procedures of the ANSYS code. This analysis attempts to address issues pertaining to an optimal combination of material, window thickness and pulse structure that will allow for a window to safely survive the extreme demands of the experiment.

  5. Search for ντ Interactions with the Nuclear Emulsion Films of the Opera Experiment

    NASA Astrophysics Data System (ADS)

    Pupilli, Fabio

    2013-11-01

    The OPERA experiment aims at measuring the νμ → ντ oscillation through the ντ appearance in an almost pure νμ beam (CNGS). For the direct identification of the short-lived τ lepton, produced in ντ CC interactions, a micrometric detection resolution is needed. Therefore the OPERA detector makes use of nuclear emulsion films, the highest spatial resolution tracking device, combined with lead plates in an emulsion cloud chamber (ECC) structure called `brick'. In this paper the nuclear emulsion analysis chain is reported; the strategy and the algorithms set up will be described together with their performances.

  6. Interactive effects of warming, eutrophication and size structure: impacts on biodiversity and food-web structure.

    PubMed

    Binzer, Amrei; Guill, Christian; Rall, Björn C; Brose, Ulrich

    2016-01-01

    Warming and eutrophication are two of the most important global change stressors for natural ecosystems, but their interaction is poorly understood. We used a dynamic model of complex, size-structured food webs to assess interactive effects on diversity and network structure. We found antagonistic impacts: Warming increases diversity in eutrophic systems and decreases it in oligotrophic systems. These effects interact with the community size structure: Communities of similarly sized species such as parasitoid-host systems are stabilized by warming and destabilized by eutrophication, whereas the diversity of size-structured predator-prey networks decreases strongly with warming, but decreases only weakly with eutrophication. Nonrandom extinction risks for generalists and specialists lead to higher connectance in networks without size structure and lower connectance in size-structured communities. Overall, our results unravel interactive impacts of warming and eutrophication and suggest that size structure may serve as an important proxy for predicting the community sensitivity to these global change stressors.

  7. Structure and membrane interactions of the homodimeric antibiotic peptide homotarsinin

    NASA Astrophysics Data System (ADS)

    Verly, Rodrigo M.; Resende, Jarbas M.; Junior, Eduardo F. C.; de Magalhães, Mariana T. Q.; Guimarães, Carlos F. C. R.; Munhoz, Victor H. O.; Bemquerer, Marcelo Porto; Almeida, Fábio C. L.; Santoro, Marcelo M.; Piló-Veloso, Dorila; Bechinger, Burkhard

    2017-01-01

    Antimicrobial peptides (AMPs) from amphibian skin are valuable template structures to find new treatments against bacterial infections. This work describes for the first time the structure and membrane interactions of a homodimeric AMP. Homotarsinin, which was found in Phyllomedusa tarsius anurans, consists of two identical cystine-linked polypeptide chains each of 24 amino acid residues. The high-resolution structures of the monomeric and dimeric peptides were determined in aqueous buffers. The dimer exhibits a tightly packed coiled coil three-dimensional structure, keeping the hydrophobic residues screened from the aqueous environment. An overall cationic surface of the dimer assures enhanced interactions with negatively charged membranes. An extensive set of biophysical data allowed us to establish structure-function correlations with antimicrobial assays against Gram-positive and Gram-negative bacteria. Although both peptides present considerable antimicrobial activity, the dimer is significantly more effective in both antibacterial and membrane biophysical assays.

  8. Structure and membrane interactions of the homodimeric antibiotic peptide homotarsinin

    PubMed Central

    Verly, Rodrigo M.; Resende, Jarbas M.; Junior, Eduardo F. C.; de Magalhães, Mariana T. Q.; Guimarães, Carlos F. C. R.; Munhoz, Victor H. O.; Bemquerer, Marcelo Porto; Almeida, Fábio C. L.; Santoro, Marcelo M.; Piló-Veloso, Dorila; Bechinger, Burkhard

    2017-01-01

    Antimicrobial peptides (AMPs) from amphibian skin are valuable template structures to find new treatments against bacterial infections. This work describes for the first time the structure and membrane interactions of a homodimeric AMP. Homotarsinin, which was found in Phyllomedusa tarsius anurans, consists of two identical cystine-linked polypeptide chains each of 24 amino acid residues. The high-resolution structures of the monomeric and dimeric peptides were determined in aqueous buffers. The dimer exhibits a tightly packed coiled coil three-dimensional structure, keeping the hydrophobic residues screened from the aqueous environment. An overall cationic surface of the dimer assures enhanced interactions with negatively charged membranes. An extensive set of biophysical data allowed us to establish structure-function correlations with antimicrobial assays against Gram-positive and Gram-negative bacteria. Although both peptides present considerable antimicrobial activity, the dimer is significantly more effective in both antibacterial and membrane biophysical assays. PMID:28102305

  9. Structure and membrane interactions of the homodimeric antibiotic peptide homotarsinin.

    PubMed

    Verly, Rodrigo M; Resende, Jarbas M; Junior, Eduardo F C; de Magalhães, Mariana T Q; Guimarães, Carlos F C R; Munhoz, Victor H O; Bemquerer, Marcelo Porto; Almeida, Fábio C L; Santoro, Marcelo M; Piló-Veloso, Dorila; Bechinger, Burkhard

    2017-01-19

    Antimicrobial peptides (AMPs) from amphibian skin are valuable template structures to find new treatments against bacterial infections. This work describes for the first time the structure and membrane interactions of a homodimeric AMP. Homotarsinin, which was found in Phyllomedusa tarsius anurans, consists of two identical cystine-linked polypeptide chains each of 24 amino acid residues. The high-resolution structures of the monomeric and dimeric peptides were determined in aqueous buffers. The dimer exhibits a tightly packed coiled coil three-dimensional structure, keeping the hydrophobic residues screened from the aqueous environment. An overall cationic surface of the dimer assures enhanced interactions with negatively charged membranes. An extensive set of biophysical data allowed us to establish structure-function correlations with antimicrobial assays against Gram-positive and Gram-negative bacteria. Although both peptides present considerable antimicrobial activity, the dimer is significantly more effective in both antibacterial and membrane biophysical assays.

  10. A Method of Simulating Fluid Structure Interactions for Deformable Decelerators

    NASA Astrophysics Data System (ADS)

    Gidzak, Vladimyr Mykhalo

    A method is developed for performing simulations that contain fluid-structure interactions between deployable decelerators and a high speed compressible flow. The problem of coupling together multiple physical systems is examined with discussion of the strength of coupling for various methods. A non-monolithic strongly coupled option is presented for fluid-structure systems based on grid deformation. A class of algebraic grid deformation methods is then presented with examples of increasing complexity. The strength of the fluid-structure coupling is validated against two analytic problems, chosen to test the time dependent behavior of structure on fluid interactions, and of fluid on structure interruptions. A one-dimentional material heating model is also validated against experimental data. Results are provided for simulations of a wind tunnel scale disk-gap-band parachute with comparison to experimental data. Finally, a simulation is performed on a flight scale tension cone decelerator, with examination of time-dependent material stress, and heating.

  11. Distance learning via interactive telecommunications: ACCESS Network's experience

    NASA Astrophysics Data System (ADS)

    Kawashima, Junichi

    1989-05-01

    A variety of formal and informal telecourses, via interactive television (one-way audio, two-way video), for distant learners are presented. Three interactive formats (telephone, phone-in on radio, and audio teleconferencing) have been utilized in linking a studio instructor with students at home or in the classroom. More interactive segments have been allocated during the broadcast to improve the teaching-learning process. A field trial to test the usefulness of a computer conferencing facility for students studying at a distance and interacting with their teachers is described.

  12. Reduced-order models for vertical human-structure interaction

    NASA Astrophysics Data System (ADS)

    Van Nimmen, Katrien; Lombaert, Geert; De Roeck, Guido; Van den Broeck, Peter

    2016-09-01

    For slender and lightweight structures, the vibration serviceability under crowd- induced loading is often critical in design. Currently, designers rely on equivalent load models, upscaled from single-person force measurements. Furthermore, it is important to consider the mechanical interaction with the human body as this can significantly reduce the structural response. To account for these interaction effects, the contact force between the pedestrian and the structure can be modelled as the superposition of the force induced by the pedestrian on a rigid floor and the force resulting from the mechanical interaction between the structure and the human body. For the case of large crowds, however, this approach leads to models with a very high system order. In the present contribution, two equivalent reduced-order models are proposed to approximate the dynamic behaviour of the full-order coupled crowd-structure system. A numerical study is performed to evaluate the impact of the modelling assumptions on the structural response to pedestrian excitation. The results show that the full-order moving crowd model can be well approximated by a reduced-order model whereby the interaction with the pedestrians in the crowd is modelled using a single (equivalent) SDOF system.

  13. The interactive image tool: adding structure to images.

    PubMed Central

    Constantinou, P.; Mather, R.; Dev, P.

    1995-01-01

    The interactive image format and tool were developed by the Stanford University Medical Media and Information Technologies (SUMMIT) group to allow medical educators to add interactive annotations and outlines to medical cross-sections, gross dissections, and clinical images. The interactive image tool (IIT) format offers a general specification for adding structural information to images. The IIT format has been used to create rich databases of image/structure information which are employed in educational software created at SUMMIT. These databases consist of information which is re-usable in other applications as well as a standalone image database. Future extensions to the IIT format will provide a means to organize information based on the structure of that information rather than on the arbitrary or haphazard links of current hypertext and hypermedia information networks. Images Figure 1 Figure 2 PMID:8563335

  14. Hey! I Can Read This! The Interactive Book Experience.

    ERIC Educational Resources Information Center

    Butt, Donna Sabino; Thurman, Kathy Barlow

    This teaching resource goes beyond songs, games, and finger plays to function as a one-of-a-kind interactive book. Teachers are given basic instructions on how to create a variety of different interactive books for their students to enjoy. Lists of materials needed to create each book are also included with the instructions. The resource book…

  15. Interaction and e-Learning: The Student Experience

    ERIC Educational Resources Information Center

    Thorpe, Mary; Godwin, Steve

    2006-01-01

    A distinction between interpersonal and content interaction was identified in the literature, and applied in research undertaken on a selection of 36 courses. These courses differed in both the kinds of interaction offered and its integration in the teaching and assessment. They included different combinations and use of conferencing, email,…

  16. Evolutionary dynamics of group interactions on structured populations: a review

    PubMed Central

    Perc, Matjaž; Gómez-Gardeñes, Jesús; Szolnoki, Attila; Floría, Luis M.; Moreno, Yamir

    2013-01-01

    Interactions among living organisms, from bacteria colonies to human societies, are inherently more complex than interactions among particles and non-living matter. Group interactions are a particularly important and widespread class, representative of which is the public goods game. In addition, methods of statistical physics have proved valuable for studying pattern formation, equilibrium selection and self-organization in evolutionary games. Here, we review recent advances in the study of evolutionary dynamics of group interactions on top of structured populations, including lattices, complex networks and coevolutionary models. We also compare these results with those obtained on well-mixed populations. The review particularly highlights that the study of the dynamics of group interactions, like several other important equilibrium and non-equilibrium dynamical processes in biological, economical and social sciences, benefits from the synergy between statistical physics, network science and evolutionary game theory. PMID:23303223

  17. Mitral valve dynamics in structural and fluid-structure interaction models.

    PubMed

    Lau, K D; Diaz, V; Scambler, P; Burriesci, G

    2010-11-01

    Modelling and simulation of heart valves is a challenging biomechanical problem due to anatomical variability, pulsatile physiological pressure loads and 3D anisotropic material behaviour. Current valvular models based on the finite element method can be divided into: those that do model the interaction between the blood and the valve (fluid-structure interaction or 'wet' models) and those that do not (structural models or 'dry' models). Here an anatomically sized model of the mitral valve has been used to compare the difference between structural and fluid-structure interaction techniques in two separately simulated scenarios: valve closure and a cardiac cycle. Using fluid-structure interaction, the valve has been modelled separately in a straight tubular volume and in a U-shaped ventricular volume, in order to analyse the difference in the coupled fluid and structural dynamics between the two geometries. The results of the structural and fluid-structure interaction models have shown that the stress distribution in the closure simulation is similar in all the models, but the magnitude and closed configuration differ. In the cardiac cycle simulation significant differences in the valvular dynamics were found between the structural and fluid-structure interaction models due to difference in applied pressure loads. Comparison of the fluid domains of the fluid-structure interaction models have shown that the ventricular geometry generates slower fluid velocity with increased vorticity compared to the tubular geometry. In conclusion, structural heart valve models are suitable for simulation of static configurations (opened or closed valves), but in order to simulate full dynamic behaviour fluid-structure interaction models are required.

  18. Modifications in structure and interaction of nanoparticle-protein-surfactant complexes in electrolyte solution

    NASA Astrophysics Data System (ADS)

    Mehan, Sumit; Kumar, S.; Aswal, V. K.; Schweins, R.

    2016-05-01

    SANS experiments of three-component system of anionic silica nanoparticles, anionic BSA protein and anionic SDS surfactants have been carried out without and with electrolyte in aqueous solution. In both the cases, the interaction of surfactant with protein results in formation of bead-necklace structure of protein-surfactant complexes in solution. These protein-surfactant complexes interact very differently with nanoparticles in absence and presence of electrolyte. In absence of electrolyte, nanoparticles remain in dispersed phase in solution, whereas with the addition of electrolyte the nanoparticles fractal aggregates are formed. SANS describes the phase behavior to be governed by competition of electrostatic and depletion interactions among the components solution.

  19. The growth of structure in interacting dark energy models

    SciTech Connect

    Caldera-Cabral, Gabriela; Maartens, Roy; Schaefer, Bjoern Malte E-mail: roy.maartens@port.ac.uk

    2009-07-01

    If dark energy interacts with dark matter, there is a change in the background evolution of the universe, since the dark matter density no longer evolves as a{sup −3}. In addition, the non-gravitational interaction affects the growth of structure. In principle, these changes allow us to detect and constrain an interaction in the dark sector. Here we investigate the growth factor and the weak lensing signal for a new class of interacting dark energy models. In these models, the interaction generalises the simple cases where one dark fluid decays into the other. In order to calculate the effect on structure formation, we perform a careful analysis of the perturbed interaction and its effect on peculiar velocities. Assuming a normalization to today's values of dark matter density and overdensity, the signal of the interaction is an enhancement (suppression) of both the growth factor and the lensing power, when the energy transfer in the background is from dark matter to dark energy (dark energy to dark matter)

  20. Structural Requirements of the Fructan-Lipid Interaction

    PubMed Central

    Vereyken, Ingrid J.; van Kuik, J. Albert; Evers, Toon H.; Rijken, Pieter J.; de Kruijff, Ben

    2003-01-01

    Fructans are a group of fructose-based oligo- and polysaccharides. They are proposed to be involved in membrane protection of plants during dehydration. In accordance with this hypothesis, they show an interaction with hydrated lipid model systems. However, the structural requirements for this interaction are not known both with respect to the fructans as to the lipids. To get insight into this matter, the interaction of several inulins and levan with lipids was investigated using a monomolecular lipid system or the MC 540 probe in a bilayer system. MD was used to get conformational information concerning the polysaccharides. It was found that levan-type fructan interacted comparably with model membranes composed of glyco- or phospholipids but showed a preference for lipids with a small headgroup. Furthermore, it was found that there was an inulin chain-length-dependent interaction with lipids. The results also suggested that inulin-type fructan had a more profound interaction with the membrane than levan-type fructan. MD simulations indicated that the favorable conformation for levan is a helix, whereas inulin tends to form random coil structures. This suggests that flexibility is an important determinant for the fructan-lipid interaction. PMID:12719244

  1. Modal identification experiment design for large space structures

    NASA Technical Reports Server (NTRS)

    Kim, Hyoung M.; Doiron, Harold H.

    1991-01-01

    This paper describes an on-orbit modal identification experiment design for large space structures. Space Station Freedom (SSF) systems design definition and structural dynamic models were used as representative large space structures for optimizing experiment design. Important structural modes of study models were selected to provide a guide for experiment design and used to assess the design performance. A pulsed random excitation technique using propulsion jets was developed to identify closely-spaced modes. A measuremenat location selection approach was developed to estimate accurate mode shapes as well as frequencies and damping factors. The data acquisition system and operational scenarios were designed to have minimal impacts on the SSF. A comprehensive simulation was conducted to assess the overall performance of the experiment design.

  2. The Fifth NASA/DOD Controls-Structures Interaction Technology Conference, part 2

    NASA Technical Reports Server (NTRS)

    Newsom, Jerry R. (Compiler)

    1993-01-01

    This publication is a compilation of the papers presented at the Fifth NASA/DoD Controls-Structures Interaction (CSI) Technology Conference held in Lake Tahoe, Nevada, March 3-5, 1992. The conference, which was jointly sponsored by the NASA Office of Aeronautics and Space Technology and the Department of Defense, was organized by the NASA Langley Research Center. The purpose of this conference was to report to industry, academia, and government agencies on the current status of controls-structures interaction technology. The agenda covered ground testing, integrated design, analysis, flight experiments and concepts.

  3. The Fifth NASA/DOD Controls-Structures Interaction Technology Conference, part 1

    NASA Technical Reports Server (NTRS)

    Newsom, Jerry R. (Compiler)

    1993-01-01

    This publication is a compilation of the papers presented at the Fifth NASA/DoD Controls-Structures Interaction (CSI) Technology Conference held in Lake Tahoe, Nevada, March 3-5, 1992. The conference, which was jointly sponsored by the NASA Office of Aeronautics and Space Technology and the Department of Defense, was organized by the NASA Langley Research Center. The purpose of this conference was to report to industry, academia, and government agencies on the current status of controls-structures interaction technology. The agenda covered ground testing, integrated design, analysis, flight experiments and concepts.

  4. Electron-interface phonon interaction in multiple quantum well structures

    NASA Astrophysics Data System (ADS)

    Sun, J. P.; Teng, H. B.; Haddad, G. I.; Stroscio, M. A.

    1998-08-01

    Intersubband relaxation rates due to electron interactions with the interface phonons are evaluated for multiple quantum well structures designed for step quantum well lasers operating at mid-infrared to submillimetre wavelengths. The interface phonon modes and electron-phonon interaction Hamiltonians for the structures are derived using the transfer matrix method, based on the macroscopic dielectric continuum model, whereas the electron wavefunctions are obtained by solving the Schrödinger equation. Fermi's golden rule is employed to calculate the electron relaxation rates between the subbands in these structures. The relaxation rates for two different structures are examined and compared with those calculated using the bulk phonon modes and the Fröhlich interaction Hamiltonian. The sum rule for the relationship between the form factors of the various localized phonon modes and the bulk phonon modes is verified. The results obtained in this work illustrate that the transfer matrix method provides a convenient way for deriving the properties of the interface phonon modes in different structures of current interest and that, for preferential electron relaxation in intersubband laser structures, the effects of the interface phonon modes are significant and should be considered for optimal design of these laser structures.

  5. Why we interact: on the functional role of the striatum in the subjective experience of social interaction.

    PubMed

    Pfeiffer, Ulrich J; Schilbach, Leonhard; Timmermans, Bert; Kuzmanovic, Bojana; Georgescu, Alexandra L; Bente, Gary; Vogeley, Kai

    2014-11-01

    There is ample evidence that human primates strive for social contact and experience interactions with conspecifics as intrinsically rewarding. Focusing on gaze behavior as a crucial means of human interaction, this study employed a unique combination of neuroimaging, eye-tracking, and computer-animated virtual agents to assess the neural mechanisms underlying this component of behavior. In the interaction task, participants believed that during each interaction the agent's gaze behavior could either be controlled by another participant or by a computer program. Their task was to indicate whether they experienced a given interaction as an interaction with another human participant or the computer program based on the agent's reaction. Unbeknownst to them, the agent was always controlled by a computer to enable a systematic manipulation of gaze reactions by varying the degree to which the agent engaged in joint attention. This allowed creating a tool to distinguish neural activity underlying the subjective experience of being engaged in social and non-social interaction. In contrast to previous research, this allows measuring neural activity while participants experience active engagement in real-time social interactions. Results demonstrate that gaze-based interactions with a perceived human partner are associated with activity in the ventral striatum, a core component of reward-related neurocircuitry. In contrast, interactions with a computer-driven agent activate attention networks. Comparisons of neural activity during interaction with behaviorally naïve and explicitly cooperative partners demonstrate different temporal dynamics of the reward system and indicate that the mere experience of engagement in social interaction is sufficient to recruit this system.

  6. A Structural Examination of the Learning Experiences Questionnaire

    ERIC Educational Resources Information Center

    Tokar, David M.; Buchanan, Taneisha S.; Subich, Linda M.; Hall, Rosalie J.; Williams, Christine M.

    2012-01-01

    The underlying factor structure of the Learning Experiences Questionnaire (LEQ; Schaub, 2004) was examined using data from 742 male and female college-age respondents. The LEQ items reflect a variety of learning experiences (generated based on Bandura's (1986, 1997) four sources of self-efficacy perceptions) that might occur in each of Holland's…

  7. Spectral function in electro-weak interactions and its impact on neutrino oscillation experiments

    SciTech Connect

    Jen, C.-M.

    2015-10-15

    Neutrino oscillation experiments have entered the high-precision era in the last few years. The oscillation parameters, as a measure of the neutrino properties, are extracted from the energy-dependent oscillation probability function. Different types of nuclear dynamics deeply influence the determination of neutrino energies in neutrino oscillation experiments. As a consequence, a comprehensive understanding of various nuclear dynamics interprets the scenario behind the neutrino interaction with nucleus and nuclei. The initial ground-state structure of the target nucleus is categorized in one typical nuclear dynamics, and its realistic description is generally referred as the spectral function (SF). Implementing the SF for each target nucleus into the GENIE neutrino event generator is the preliminary step necessary to obtain a reliable determination of the kinematics of all detectable final-products from neutrino interactions. At the intermedium-range of neutrino energies (∼ 1 GeV), the kinematic energy reconstruction is the vastly used approach and consists in identifying final-products as coming from the charged-current quasi-elastic-like (CCQE-like) neutrino interactions.

  8. Cross-kingdom interactions matter: fungal-mediated interactions structure an insect community on oak.

    PubMed

    Tack, Ayco J M; Gripenberg, Sofia; Roslin, Tomas

    2012-03-01

    Although phytophagous insects and plant pathogens frequently share the same host plant, interactions among such phylogenetically distant taxa have received limited attention. Here, we place pathogens and insects in the context of a multitrophic-level community. Focusing on the invasive powdery mildew Erysiphe alphitoides and the insect community on oak (Quercus robur), we demonstrate that mildew-insect interactions may be mediated by both the host plant and by natural enemies, and that the trait-specific outcome of individual interactions can range from negative to positive. Moreover, mildew affects resource selection by insects, thereby modifying the distribution of a specialist herbivore at two spatial scales (within and among trees). Finally, a long-term survey suggests that species-specific responses to mildew scale up to generate landscape-level variation in the insect community structure. Overall, our results show that frequently overlooked cross-kingdom interactions may play a major role in structuring terrestrial plant-based communities.

  9. Interactive diversity promotes the evolution of cooperation in structured populations

    NASA Astrophysics Data System (ADS)

    Su, Qi; Li, Aming; Zhou, Lei; Wang, Long

    2016-10-01

    Evolutionary games on networks traditionally assume that each individual adopts an identical strategy to interact with all its neighbors in each generation. Considering the prevalent diversity of individual interactions in the real society, here we propose the concept of interactive diversity, which allows individuals to adopt different strategies against different neighbors in each generation. We investigate the evolution of cooperation based on the edge dynamics rather than the traditional nodal dynamics in networked systems. The results show that, without invoking any other mechanisms, interactive diversity drives the frequency of cooperation to a high level for a wide range of parameters in both well-mixed and structured populations. Even in highly connected populations, cooperation still thrives. When interactive diversity and large topological heterogeneity are combined together, however, in the relaxed social dilemma, cooperation level is lower than that with just one of them, implying that the combination of many promotive factors may make a worse outcome. By an analytical approximation, we get the condition under which interactive diversity provides more advantages for cooperation than traditional evolutionary dynamics does. Numerical simulations validating the approximation are also presented. Our work provides a new line to explore the latent relation between the ubiquitous cooperation and individuals’ distinct responses in different interactions. The presented results suggest that interactive diversity should receive more attention in pursuing mechanisms fostering cooperation.

  10. NMR Solution Structure, Stability, and Interaction of the Recombinant Bovine Fibrinogen αC-Domain Fragment†

    PubMed Central

    Burton, Robert A.; Tsurupa, Galina; Hantgan, Roy R.; Tjandra, Nico; Medved, Leonid

    2008-01-01

    According to the current hypothesis, in fibrinogen, the COOH-terminal portions of two Aα chains are folded into compact αC-domains that interact intramolecularly with each other and with the central region of the molecule; in fibrin, the αC-domains switch to an intermolecular interaction resulting in αC polymers. In agreement, our recent NMR study identified within the bovine fibrinogen Aα374-538 αC-domain fragment an ordered compact structure including a β-hairpin restricted at the base by a 423–453 disulfide linkage. To establish the complete structure of the αC-domain and to further test the hypothesis, we expressed a shorter αC-fragment, Aα406-483, and performed detailed analysis of its structure, stability, and interactions. NMR experiments on the Aα406-483 fragment identified a second loose β-hairpin formed by residues 459–476, yielding a structure consisting of an intrinsically unstable mixed parallel/anti-parallel β-sheet. Size-exclusion chromatography and sedimentation velocity experiments revealed that the Aα406-483 fragment forms soluble oligomers whose fraction increases with increasing concentration. This was confirmed by sedimentation equilibrium analysis, which also revealed that the addition of each monomer to an assembling αC oligomer substantially increases its stabilizing free energy. In agreement, unfolding experiments monitored by CD established that oligomerization of Aα406-483 results in increased thermal stability. Altogether, these experiments establish the complete NMR solution structure of the Aα406-483 αC-domain fragment, provide direct evidence for the intra- and intermolecular interactions between the αC-domains, and confirm that these interactions are thermodynamically driven. PMID:17590019

  11. A space station Structures and Assembly Verification Experiment, SAVE

    NASA Technical Reports Server (NTRS)

    Russell, R. A.; Raney, J. P.; Deryder, L. J.

    1986-01-01

    The Space Station structure has been baselined to be a 5 M (16.4 ft) erectable truss. This structure will provide the overall framework to attach laboratory modules and other systems, subsystems and utilities. The assembly of this structure represents a formidable EVA challenge. To validate this capability the Space Station Structures/Dynamics Technical Integration Panel (TIP) met to develop the necessary data for an integrated STS structures flight experiment. As a result of this meeting, the Langley Research Center initiated a joint Langley/Boeing Aerospace Company study which supported the structures/dynamics TIP in developing the preliminary definition and design of a 5 M erectable space station truss and the resources required for a proposed flight experiment. The purpose of the study was to: (1) devise methods of truss assembly by astronauts; (2) define a specific test matrix for dynamic characterization; (3) identify instrumentation and data system requirements; (4) determine the power, propulsion and control requirements for the truss on-orbit for 3 years; (5) study the packaging of the experiment in the orbiter cargo bay; (6) prepare a preliminary cost estimate and schedule for the experiment; and (7) provide a list of potential follow-on experiments using the structure as a free flyer. The results of this three month study are presented.

  12. [Cell-to-cell interactions in microgravity: experiments in vitro].

    PubMed

    Buravkova, L B; Grigorieva, O V; Konstantinova, N A; Guershovich, Yu G; Guershovich, P M

    2013-01-01

    The review summarizes the results of studying the space and simulated microgravity effects on cell-to-cell interactions in three models: 1) interaction of a human lymphocytes culture with a subinoculated suspension culture of tumor myeloblasts K-562; 2) formation of embryoid bodies and differentiation of mice embryonic stem cells (ESCs); 3) gene differentiation and expression in multipotent mesenchymal cells (MCSs) obtained from the human marrow. It was shown that microgravity modifies the cell-to-cell interactions without cell contact inhibition; however, micro-g causes reversible changes in expression of genes responsible for regulation of the cytoskeleton, focal adhesion proteins, and some cytokines. Prolonged exposure of progenitor cells in simulated microgravity inhibits the differentiation processes of and reprofiles significantly expression of the genes that control various cell activities, including cell-to-cell interactions.

  13. Giant Electron-Hole Interactions in Confined Layered Structures for Molecular Oxygen Activation.

    PubMed

    Wang, Hui; Chen, Shichuan; Yong, Dingyu; Zhang, Xiaodong; Li, Shuang; Shao, Wei; Sun, Xianshun; Pan, Bicai; Xie, Yi

    2017-04-05

    Numerous efforts have been devoted to understanding the excitation processes of photocatalysts, whereas the potential Coulomb interactions between photogenerated electrons and holes have been long ignored. Once these interactions are considered, excitonic effects will arise that undoubtedly influence the sunlight-driven catalytic processes. Herein, by taking bismuth oxyhalide as examples, we proposed that giant electron-hole interactions would be expected in confined layered structures, and excitons would be the dominating photoexcited species. Photocatalytic molecular oxygen activation tests were performed as a proof of concept, where singlet oxygen generation via energy transfer process was brightened. Further experiments verify that structural confinement is curial to the giant excitonic effects, where the involved catalytic process could be readily regulated via facet-engineering, thus enabling diverse reactive oxygen species generation. This study not only provides an excitonic prospective on photocatalytic processes, but also paves a new approach for pursuing systems with giant electron-hole interactions.

  14. Fluid-structure Interaction Simulations of Deformable Soft Tissue

    NASA Astrophysics Data System (ADS)

    Borazjani, Iman

    2011-11-01

    Soft tissue interacts with the surrounding fluid environment in many biological and biomedical applications. Simulating such an interaction is quite challenging due to the large non-linear deformations of tissue, flow pulsatility, transition to turbulence, and non-linear fluid-structure interaction. We have extended our previous three-dimensional fluid-structure interaction (FSI) framework for rigid bodies (Borazjani, Ge, and Sotiropoulos, Journal of Computational Physics, 2008) to deformable soft tissue by coupling our incompressible Navier-Stokes solver for fluids with a non-linear large deformation finite element method for soft tissue. We use Fung-type constitutive law for the soft tissue that can capture the stress-strain behavior of the tissue. The FSI solver adopts a strongly-coupled partitioned approach that is stabilized with under-relaxation and Aitken acceleration technique. We validate our solvers against the experimental data for tissue valves and elastic tubes. We show the capabilities of our solver by simulating the fluid-structure interaction of tissue valves implanted in the aortic positions and elastic collapsible tubes. This work was partly supported by the Center for Computational Research at the University at Buffalo.

  15. Operational experience with room temperature continuous wave accelerator structures

    NASA Astrophysics Data System (ADS)

    Alimov, A. S.; Ishkhanov, B. S.; Piskarev, I. M.; Shvedunov, V. I.; Tiunov, A. V.

    1993-05-01

    The paper reports the results of the computer simulation of parameters of the on-axis coupled accelerator structure for the continuous wave racetrack microtron. The operational experience with the accelerating sections on the basis of the on-axis coupled structure is described.

  16. Interactive Hangman teaches amino acid structures and abbreviations.

    PubMed

    Pennington, Britney O; Sears, Duane; Clegg, Dennis O

    2014-01-01

    We developed an interactive exercise to teach students how to draw the structures of the 20 standard amino acids and to identify the one-letter abbreviations by modifying the familiar game of "Hangman." Amino acid structures were used to represent single letters throughout the game. To provide additional practice in identifying structures, hints to the answers were written in "amino acid sentences" for the students to translate. Students were required to draw the structure of the corresponding letter they wished to guess on a whiteboard. Each student received a reference sheet of the structures and abbreviations, but was required to draw from memory when guessing a letter. Preassessments and postassessments revealed a drastic improvement in the students' ability to recognize and draw structures from memory. This activity provides a fun, educational game to play in biochemistry discussion sections or during long incubations in biochemistry laboratories.

  17. KLIFS: a structural kinase-ligand interaction database

    PubMed Central

    Kooistra, Albert J.; Kanev, Georgi K.; van Linden, Oscar P.J.; Leurs, Rob; de Esch, Iwan J.P.; de Graaf, Chris

    2016-01-01

    Protein kinases play a crucial role in cell signaling and are important drug targets in several therapeutic areas. The KLIFS database contains detailed structural kinase-ligand interaction information derived from all (>2900) structures of catalytic domains of human and mouse protein kinases deposited in the Protein Data Bank in order to provide insights into the structural determinants of kinase-ligand binding and selectivity. The kinase structures have been processed in a consistent manner by systematically analyzing the structural features and molecular interaction fingerprints (IFPs) of a predefined set of 85 binding site residues with bound ligands. KLIFS has been completely rebuilt and extended (>65% more structures) since its first release as a data set, including: novel automated annotation methods for (i) the assessment of ligand-targeted subpockets and the analysis of (ii) DFG and (iii) αC-helix conformations; improved and automated protocols for (iv) the generation of sequence/structure alignments, (v) the curation of ligand atom and bond typing for accurate IFP analysis and (vi) weekly database updates. KLIFS is now accessible via a website (http://klifs.vu-compmedchem.nl) that provides a comprehensive visual presentation of different types of chemical, biological and structural chemogenomics data, and allows the user to easily access, compare, search and download the data. PMID:26496949

  18. Dynamic Soil-Structure Interaction Behavior on the Seafloor

    DTIC Science & Technology

    1988-08-01

    34 - .. .-- -- , ,.,m .-- l I ,li m~ii, ; li. ,m,, l l ~ l l l ~i- Forword DyA~mic Soil-Structure Interaction (S-SI) behavior on the sea floor describes the...using Fast Fourier and profile C has all strengths increased by 3-1/3. The Transform methods. The second advantage of the pro- actual water depth at

  19. Development Causal Structures of Organism-Environment Interactions

    ERIC Educational Resources Information Center

    Labouvie, E. W.

    1974-01-01

    Proposes an extension of multivariate, structural analyses for studying organism-environment interactions. Based on characteristics of the assumed feedback mechanisms between behavioral and environmental systems, it appears possible to analyze longitudinally ordered sequences in terms of recursive versus nonrecursive and distal versus proximal…

  20. Website on Protein Interaction and Protein Structure Related Work

    NASA Technical Reports Server (NTRS)

    Samanta, Manoj; Liang, Shoudan; Biegel, Bryan (Technical Monitor)

    2003-01-01

    In today's world, three seemingly diverse fields - computer information technology, nanotechnology and biotechnology are joining forces to enlarge our scientific knowledge and solve complex technological problems. Our group is dedicated to conduct theoretical research exploring the challenges in this area. The major areas of research include: 1) Yeast Protein Interactions; 2) Protein Structures; and 3) Current Transport through Small Molecules.

  1. Control-structure-thermal interactions in analysis of lunar telescopes

    NASA Technical Reports Server (NTRS)

    Thompson, Roger C.

    1992-01-01

    The lunar telescope project was an excellent model for the CSTI study because a telescope is a very sensitive instrument, and thermal expansion or mechanical vibration of the mirror assemblies will rapidly degrade the resolution of the device. Consequently, the interactions are strongly coupled. The lunar surface experiences very large temperature variations that range from approximately -180 C to over 100 C. Although the optical assemblies of the telescopes will be well insulated, the temperature of the mirrors will inevitably fluctuate in a similar cycle, but of much smaller magnitude. In order to obtain images of high quality and clarity, allowable thermal deformations of any point on a mirror must be less than 1 micron. Initial estimates indicate that this corresponds to a temperature variation of much less than 1 deg through the thickness of the mirror. Therefore, a lunar telescope design will most probably include active thermal control, a means of controlling the shape of the mirrors, or a combination of both systems. Historically, the design of a complex vehicle was primarily a sequential process in which the basic structure was defined without concurrent detailed analyses or other subsystems. The basic configuration was then passed to the different teams responsible for each subsystem, and their task was to produce a workable solution without requiring major alterations to any principal components or subsystems. Consequently, the final design of the vehicle was not always the most efficient, owing to the fact that each subsystem design was partially constrained by the previous work. This procedure was necessary at the time because the analysis process was extremely time-consuming and had to be started over with each significant alteration of the vehicle. With recent advances in the power and capacity of small computers, and the parallel development of powerful software in structural, thermal, and control system analysis, it is now possible to produce very

  2. Linkers in the structural biology of protein-protein interactions.

    PubMed

    Reddy Chichili, Vishnu Priyanka; Kumar, Veerendra; Sivaraman, J

    2013-02-01

    Linkers or spacers are short amino acid sequences created in nature to separate multiple domains in a single protein. Most of them are rigid and function to prohibit unwanted interactions between the discrete domains. However, Gly-rich linkers are flexible, connecting various domains in a single protein without interfering with the function of each domain. The advent of recombinant DNA technology made it possible to fuse two interacting partners with the introduction of artificial linkers. Often, independent proteins may not exist as stable or structured proteins until they interact with their binding partner, following which they gain stability and the essential structural elements. Gly-rich linkers have been proven useful for these types of unstable interactions, particularly where the interaction is weak and transient, by creating a covalent link between the proteins to form a stable protein-protein complex. Gly-rich linkers are also employed to form stable covalently linked dimers, and to connect two independent domains that create a ligand-binding site or recognition sequence. The lengths of linkers vary from 2 to 31 amino acids, optimized for each condition so that the linker does not impose any constraints on the conformation or interactions of the linked partners. Various structures of covalently linked protein complexes have been described using X-ray crystallography, nuclear magnetic resonance and cryo-electron microscopy techniques. In this review, we evaluate several structural studies where linkers have been used to improve protein quality, to produce stable protein-protein complexes, and to obtain protein dimers.

  3. Cellular Shape Memory Alloy Structures: Experiments & Modeling (Part 1)

    DTIC Science & Technology

    2012-08-01

    AFOSR  Grant  #FA9550-­‐08-­‐1-­‐0313 Cellular  Shape  Memory   Alloy  Structures:   Experiments  &  Modeling J.  Shaw  (UM...2012 4. TITLE AND SUBTITLE Cellular Shape Memory Alloy Structures: Experiments & Modeling (Part 1) 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c...dense,  0.37  g/cc) Combine benefits of light-weight cellular structures with Shape Memory Alloy (SMA) adaptive behavior CombinaKon •Amplified

  4. MOLVIE: an interactive visualization environment for molecular structures.

    PubMed

    Sun, Huandong; Li, Ming; Xu, Ying

    2003-05-01

    A Molecular visualization interactive environment (MOLVIE), is designed to display three-dimensional (3D) structures of molecules and support the structural analysis and research on proteins. The paper presents the features, design considerations and applications of MOLVIE, especially the new functions used to compare the structures of two molecules and view the partial fragment of a molecule. Being developed in JAVA, MOLVIE is platform-independent. Moreover, it may run on a webpage as an applet for remote users. MOLVIE is available at http://www.cs.ucsb.edu/~mli/Bioinf/software/index.html.

  5. Structural mode significance using INCA. [Interactive Controls Analysis computer program

    NASA Technical Reports Server (NTRS)

    Bauer, Frank H.; Downing, John P.; Thorpe, Christopher J.

    1990-01-01

    Structural finite element models are often too large to be used in the design and analysis of control systems. Model reduction techniques must be applied to reduce the structural model to manageable size. In the past, engineers either performed the model order reduction by hand or used distinct computer programs to retrieve the data, to perform the significance analysis and to reduce the order of the model. To expedite this process, the latest version of INCA has been expanded to include an interactive graphical structural mode significance and model order reduction capability.

  6. Geographic structure in a widespread plant-mycorrhizal interaction: pines and false truffles.

    PubMed

    Hoeksema, J D; Thompson, J N

    2007-05-01

    Mutualistic interactions are likely to exhibit a strong geographic mosaic in their coevolutionary dynamics, but the structure of geographic variation in these interactions is much more poorly characterized than in host-parasite interactions. We used a cross-inoculation experiment to characterize the scales and patterns at which geographic structure has evolved in an interaction between three pine species and one ectomycorrhizal fungus species along the west coast of North America. We found substantial and contrasting patterns of geographic interaction structure for the plants and fungi. The fungi exhibited a clinal pattern of local adaptation to their host plants across the geographic range of three coastal pines. In contrast, plant growth parameters were unaffected by fungal variation, but varied among plant populations and species. Both plant and fungal performance measures varied strongly with latitude. This set of results indicates that in such widespread species interactions, interacting species may evolve asymmetrically in a geographic mosaic because of differing evolutionary responses to clinally varying biotic and abiotic factors.

  7. From Geometry to Diagnosis: Experiences of Geomatics in Structural Engineering

    NASA Astrophysics Data System (ADS)

    Riveiro, B.; Arias, P.; Armesto, J.; Caamaño, J. C.; Solla, M.

    2012-07-01

    Terrestrial photogrammetry and laser scanning are technologies that have been successfully used for metric surveying and 3D modelling in many different fields (archaeological and architectural documentation, industrial retrofitting, mining, structural monitoring, road surveying, etc.). In the case of structural applications, these techniques have been successfully applied to 3D modelling and sometimes monitoring; but they have not been sufficiently implemented to date, as routine tools in infrastructure management systems, in terms of automation of data processing and integration in the condition assessment procedures. In this context, this paper presents a series of experiences in the usage of terrestrial photogrammetry and laser scanning in the context of dimensional and structural evaluation of structures. These experiences are particularly focused on historical masonry structures, but modern prestressed concrete bridges are also investigated. The development of methodological procedures for data collection, and data integration in some cases, is tackled for each particular structure (with access limitations, geometrical configuration, range of measurement, etc.). The accurate geometrical information provided by both terrestrial techniques motivates the implementation of such results in the complex, and sometimes slightly approximated, geometric scene that is frequently used in structural analysis. In this sense, quantitative evaluating of the influence of real and accurate geometry in structural analysis results must be carried out. As main result in this paper, a series of experiences based on the usage of photogrammetric and laser scanning to structural engineering are presented.

  8. Control/structure interaction methods for space station power systems

    NASA Technical Reports Server (NTRS)

    Blelloch, Paul

    1989-01-01

    The Structural Dynamics Research Corporation and the NASA Lewis Research Center have been working together to develop tools and methods for the analysis of control/structure interaction problems related to the space station power systems. Flexible modes of the solar arrays below 0.1 Hz, suggest that even for relatively slow control systems, the potential for control/structure interaction exists. The emphasis of the effort has been to develop tools which couple NASTRAN's powerful capabilities in structural dynamics with EASY5's powerful capabilities in control systems analysis. One product is an interface software package called CO-ST-IN for COntrol-STructure-INteraction. CO-ST-IN acts to translate data between NASTRAN and EASY5, facilitating the analysis of complex coupled problems. Interfaces to SDRC I-DEAS and MATRIXx are also offered. Beside transferring standard modal information, CO-ST-IN implements a number of advanced methods. These include a modal ordering algorithm that helps eliminate uncontrollable or unobservable modes from the analysis, an implementation of the more accurate mode acceleration algorithm for recovery of element forces and stresses directly in EASY5 and an implementation of fixed interface modes in NASTRAN, which reduces the error in the closed-loop model due to the use of truncated mode sets.

  9. Nail-like targets for laser plasma interaction experiments

    SciTech Connect

    Pasley, J; Wei, M; Shipton, E; Chen, S; Ma, T; Beg, F N; Alexander, N; Stephens, R B; MacPhee, A G; Hey, D; Pape, S L; Patel, P; Mackinnon, A J; Key, M H; Offermann, D; Link, A; Chowdhury, E; Van-Woerkom, L D; Freeman, R R

    2007-12-18

    The interaction of ultra-high power picosecond laser pulses with solid targets is of interest both for benchmarking the results of hybrid particle in cell (PIC) codes and also for applications to re-entrant cone guided fast ignition. We describe the construction of novel targets in which copper/titanium wires are formed into 'nail-like' objects by a process of melting and micromachining, so that energy can be reliably coupled to a 24 {micro}m diameter wire. An extreme-ultraviolet image of the interaction of the Titan laser with such a target is shown.

  10. Interactive Approach on Experiments in Mechanical Engineering : Vibration

    NASA Astrophysics Data System (ADS)

    Kumon, Makoto; Torigoe, Ippei; Mizumoto, Ikuro; Yamaguchi, Teruo; Kohzawa, Ryuichi; Ohshima, Yasutaka

    Experiments in the engineering education play important roles in motivating students to study voluntarily. A trial aiming to enhance this effect in the experiment of vibration at Mechanical System Engineering, Kumamoto University is introduced. The trial consists of 1) oral presentation by students, 2) web-based learning system and 3) feedback through reports. An evaluation by questionnaire was conducted to show the validity of this trial. This result revealed that the trial succeeded to encourage students.

  11. Shock Wave / Boundary Layer Interaction Experiment on Control Surface

    DTIC Science & Technology

    2007-06-01

    like ice cubes do in water. When heat is added to the water/ ice mixture, ice melts , but the temperature of the mixture remains at 0ºC until all the ice ...ramp will likely experience similar oscillations (Figure 1). Various other groups have also performed numerical [9][10] and experimental [11][12][13... experimental data from all payloads in addition to some “housekeeping” signals. It also sends experiment control signals to the payloads. The

  12. Adaptivity and smart algorithms for fluid-structure interaction

    NASA Technical Reports Server (NTRS)

    Oden, J. Tinsley

    1990-01-01

    This paper reviews new approaches in CFD which have the potential for significantly increasing current capabilities of modeling complex flow phenomena and of treating difficult problems in fluid-structure interaction. These approaches are based on the notions of adaptive methods and smart algorithms, which use instantaneous measures of the quality and other features of the numerical flowfields as a basis for making changes in the structure of the computational grid and of algorithms designed to function on the grid. The application of these new techniques to several problem classes are addressed, including problems with moving boundaries, fluid-structure interaction in high-speed turbine flows, flow in domains with receding boundaries, and related problems.

  13. Structure-based prediction of host-pathogen protein interactions.

    PubMed

    Mariano, Rachelle; Wuchty, Stefan

    2017-03-16

    The discovery, validation, and characterization of protein-based interactions from different species are crucial for translational research regarding a variety of pathogens, ranging from the malaria parasite Plasmodium falciparum to HIV-1. Here, we review recent advances in the prediction of host-pathogen protein interfaces using structural information. In particular, we observe that current methods chiefly perform machine learning on sequence and domain information to produce large sets of candidate interactions that are further assessed and pruned to generate final, highly probable sets. Structure-based studies have also emphasized the electrostatic properties and evolutionary transformations of pathogenic interfaces, supplying crucial insight into antigenic determinants and the ways pathogens compete for host protein binding. Advancements in spectroscopic and crystallographic methods complement the aforementioned techniques, permitting the rigorous study of true positives at a molecular level. Together, these approaches illustrate how protein structure on a variety of levels functions coordinately and dynamically to achieve host takeover.

  14. Genetic Risk by Experience Interaction for Childhood Internalizing Problems: Converging Evidence across Multiple Methods

    ERIC Educational Resources Information Center

    Vendlinski, Matthew K.; Lemery-Chalfant, Kathryn; Essex, Marilyn J.; Goldsmith, H. Hill

    2011-01-01

    Background: Identifying how genetic risk interacts with experience to predict psychopathology is an important step toward understanding the etiology of mental health problems. Few studies have examined genetic risk by experience interaction (GxE) in the development of childhood psychopathology. Methods: We used both co-twin and parent mental…

  15. Optimizing Interacting Potentials to Form Targeted Materials Structures

    SciTech Connect

    Torquato, Salvatore

    2015-09-28

    Conventional applications of the principles of statistical mechanics (the "forward" problems), start with particle interaction potentials, and proceed to deduce local structure and macroscopic properties. Other applications (that may be classified as "inverse" problems), begin with targeted configurational information, such as low-order correlation functions that characterize local particle order, and attempt to back out full-system configurations and/or interaction potentials. To supplement these successful experimental and numerical "forward" approaches, we have focused on inverse approaches that make use of analytical and computational tools to optimize interactions for targeted self-assembly of nanosystems. The most original aspect of our work is its inherently inverse approach: instead of predicting structures that result from given interaction potentials among particles, we determine the optimal potential that most robustly stabilizes a given target structure subject to certain constraints. Our inverse approach could revolutionize the manner in which materials are designed and fabricated. There are a number of very tangible properties (e.g. zero thermal expansion behavior), elastic constants, optical properties for photonic applications, and transport properties.

  16. CO-ST-IN - CONTROL-STRUCTURE-INTERACTION

    NASA Technical Reports Server (NTRS)

    Carney, K.

    1994-01-01

    CO-ST-IN is a program developed for NASA to help facilitate the study of Control Structure Interaction, the dynamic coupling between control systems and flexible structures. Current space structures are larger and more flexible than previous designs. At the same time, increased demands are being placed on the performance of control systems. For many space structures it is essential to analyze the interaction of control systems with structural flexibility. CO-ST-IN was designed to complement and enhance rather than to replace the structural dynamics and control system analysis tools already available at NASA. The functions performed by CO-ST-IN can be roughly divided into three areas: 1) data transfer between structural dynamics and control systems software (MSC/NASTRAN, I-DEAS, EASY5 and MATRIXx are currently supported to varying degrees); 2) modal selection at both the component and system level as a means of model reduction; and 3) simulation of the coupled system (given simple controllers). CO-ST-IN reduces the size of the structural model by selecting system modes on the basis of input/output coupling (three algorithms along with a number of other options are offered). This allows the analyst to use far fewer modes in the coupled analysis, since the program will select those which are most closely coupled to the structural inputs and outputs. Another special capability is the calculation of structural outputs such as element forces and stresses using either the mode acceleration or mode displacement approach directly within the coupled simulation. This eliminates the need to return to MSC/NASTRAN for recovery of this data, accelerating the turnaround time of analyses. The transfer of input forces for transient analysis in MSC/NASTRAN is also supported. CO-ST-IN was implemented on a DEC VAX with the VMS operating system. This FORTRAN77 program has a memory requirement of 9.4 MB. CO-ST-IN was developed in 1989.

  17. Measurement of Phase Space Structure of Fast Ions Interacting with Alfven Eigenmodes

    NASA Astrophysics Data System (ADS)

    Nagaoka, Kenichi; Osakabe, Masaki; Isobe, Mitsutaka; Ogawa, Kunihiro; Suzuki, Yasuhiro; Kobayashi, Shinji; Yamamoto, Satoshi; Miyoshi, Yoshizumi; Katoh, Yuto; Fontdecaba, Jose M.

    2015-11-01

    Experimentally observed Alfven eigenmodes (AEs) shows nonlinear behaviors such as intermittency, fast sweep in frequency and so on. In order to understand such nonlinear behaviors of AEs, it is widely recognized that the phase space structure have to be taken into account. However, there are few direct measurements of phase space structure in experiments so far. Here, we propose to apply the wave-particle interaction analyzer (WPIA) technique being developed for magnetosphere plasma physics (ERG project) to magnetically confinement fusion experiments. In the meeting, we present a high speed pulse analyzer system for WPIA using the field programmable gate array (FPGA) module and discuss the phase space structures observed in the LHD experiment. This work was supported by JSPS KAKENHI Grant-in-Aid for Young Scientists (A) 26709071.

  18. Fluid-structure interaction in compliant insect wings.

    PubMed

    Eberle, A L; Reinhall, P G; Daniel, T L

    2014-06-01

    Insect wings deform significantly during flight. As a result, wings act as aeroelastic structures wherein both the driving motion of the structure and the aerodynamic loading of the surrounding fluid potentially interact to modify wing shape. We explore two key issues associated with the design of compliant wings: over a range of driving frequencies and phases of pitch-heave actuation, how does wing stiffness influence (1) the lift and thrust generated and (2) the relative importance of fluid loading on the shape of the wing? In order to examine a wide range of parameters relevant to insect flight, we develop a computationally efficient, two-dimensional model that couples point vortex methods for fluid force computations with structural finite element methods to model the fluid-structure interaction of a wing in air. We vary the actuation frequency, phase of actuation, and flexural stiffness over a range that encompasses values measured for a number of insect taxa (10-90 Hz; 0-π rad; 10(-7)-10(-5) N m(2)). We show that the coefficients of lift and thrust are maximized at the first and second structural resonant frequencies of the system. We also show that even in regions of structural resonance, fluid loading never contributes more than 20% to the development of flight forces.

  19. Visual Interaction with Dimensionality Reduction: A Structured Literature Analysis.

    PubMed

    Sacha, Dominik; Zhang, Leishi; Sedlmair, Michael; Lee, John A; Peltonen, Jaakko; Weiskopf, Daniel; North, Stephen C; Keim, Daniel A

    2017-01-01

    Dimensionality Reduction (DR) is a core building block in visualizing multidimensional data. For DR techniques to be useful in exploratory data analysis, they need to be adapted to human needs and domain-specific problems, ideally, interactively, and on-the-fly. Many visual analytics systems have already demonstrated the benefits of tightly integrating DR with interactive visualizations. Nevertheless, a general, structured understanding of this integration is missing. To address this, we systematically studied the visual analytics and visualization literature to investigate how analysts interact with automatic DR techniques. The results reveal seven common interaction scenarios that are amenable to interactive control such as specifying algorithmic constraints, selecting relevant features, or choosing among several DR algorithms. We investigate specific implementations of visual analysis systems integrating DR, and analyze ways that other machine learning methods have been combined with DR. Summarizing the results in a "human in the loop" process model provides a general lens for the evaluation of visual interactive DR systems. We apply the proposed model to study and classify several systems previously described in the literature, and to derive future research opportunities.

  20. IMMERSE: Interactive Mentoring for Multimodal Experiences in Realistic Social Encounters

    DTIC Science & Technology

    2015-08-28

    Social Perception 5.2.2 Expressing Social Interaction 5.2.3 Performance Guidance 5.2.4 Performance Management 5.2.5 Attention Management 6...the restrictions on the title page of this report. Page ii 5.2.1!Social Perception ...for assessing etiquette perceptions and misperceptions among culturally diverse participants; and Dr. Alan Collins, who served as a senior advisor on

  1. Rotor-Fuselage Interaction: Analysis and Validation with Experiment

    NASA Technical Reports Server (NTRS)

    Berry, John D.; Bettschart, Nicolas

    1997-01-01

    The problem of rotor-fuselage aerodynamic interaction has to be considered in industry applications from various aspects. First, in order to increase helicopter speed and reduce operational costs, rotorcraft tend to be more and more compact, with a main rotor closer to the fuselage surface. This creates significant perturbations both on the main rotor and on the fuselage, including steady and unsteady effects due to blade and wake passage and perturbed inflow at the rotor disk. Furthermore,the main rotor wake affects the tail boom, empennage and anti-torque system. This has important consequences for helicopter control and vibrations at low speeds and also on tail rotor acoustics (main rotor wake-tail rotor interactions). This report describes the US Army-France MOD cooperative work on this problem from both the theoretical and experimental aspects. Using experimental 3D velocity field and fuselage surface pressure measurements, three codes that model the interactions of a helicopter rotor with a fuselage are compared. These comparisons demonstrate some of the strengths and weaknesses of current models for the combined rotor-fuselage analysis.

  2. First Laser-Plasma Interaction and Hohlraum Experiments on NIF

    SciTech Connect

    Dewald, E L; Glenzer, S H; Landen, O L; Suter, L J; Jones, O S; Schein, J; Froula, D; Divol, L; Campbell, K; Schneider, M S; McDonald, J W; Niemann, C; Mackinnon, A J

    2005-06-17

    Recently the first hohlraum experiments have been performed at the National Ignition Facility (NIF) in support of indirect drive Inertial Confinement Fusion (ICF) designs. The effects of laser beam smoothing by spectral dispersion (SSD) and polarization smoothing (PS) on the beam propagation in long scale gas-filled pipes has been studied at plasma scales as found in indirect drive gas filled ignition hohlraum designs. The long scale gas-filled target experiments have shown propagation over 7 mm of dense plasma without filamentation and beam break up when using full laser smoothing. Vacuum hohlraums have been irradiated with laser powers up to 6 TW, 1-9 ns pulse lengths and energies up to 17 kJ to activate several diagnostics, to study the hohlraum radiation temperature scaling with the laser power and hohlraum size, and to make contact with hohlraum experiments performed at the NOVA and Omega laser facilities. Subsequently, novel long laser pulse hohlraum experiments have tested models of hohlraum plasma filling and long pulse hohlraum radiation production. The validity of the plasma filling assessment in analytical models and in LASNEX calculations has been proven for the first time. The comparison of these results with modeling will be discussed.

  3. Peculiarities of Cultural Interaction in Education: The US Experience

    ERIC Educational Resources Information Center

    Baybakova, Olga; Sidun, Larysa

    2015-01-01

    Article deals with the problem of multicultural education. Ukraine, being a multicultural society, requires a new conception of the world, aimed at integrating cultures and nations, their further convergence as well as cultural enrichment. In this context the experience of many foreign countries, especially the USA, is very interesting. This…

  4. Uncovering the structural basis of protein interactions with efficient clustering of 3-D interaction interfaces.

    PubMed

    Aung, Z; Tan, S-H; Ng, S-K; Tan, K-L

    2007-01-01

    The biological mechanisms with which proteins interact with one another are best revealed by studying the structural interfaces between interacting proteins. Protein-protein interfaces can be extracted from 3-D structural data of protein complexes and then clustered to derive biological insights. However, conventional protein interface clustering methods lack computational scalability and statistical support. In this work, we present a new method named "PPiClust" to systematically encode, cluster and analyze similar 3-D interface patterns in protein complexes efficiently. Experimental results showed that our method is effective in discovering visually consistent and statistically significant clusters of interfaces, and at the same time sufficiently time-efficient to be performed on a single computer. The interface clusters are also useful for uncovering the structural basis of protein interactions. Analysis of the resulting interface clusters revealed groups of structurally diverse proteins having similar interface patterns. We also found, in some of the interface clusters, the presence of well-known linear binding motifs which were non-contiguous in the primary sequences. These results suggest that PPiClust can discover not only statistically significant but also biologically significant protein interface clusters from protein complex structural data.

  5. Optimal experiment design for identification of large space structures

    NASA Technical Reports Server (NTRS)

    Bayard, D. S.; Hadaegh, F. Y.; Meldrum, D. R.

    1988-01-01

    The optimal experiment design for on-orbit identification of modal frequency and damping parameters in large flexible space structures is discussed. The main result is a separation principle for D-optimal design which states that under certain conditions the sensor placement problem is decoupled from the input design problem. This decoupling effect significantly simplifies the overall optimal experiment design determination for large MIMO structural systems with many unknown modal parameters. The error from using the uncoupled design is estimated in terms of the inherent damping of the structure. A numerical example is given, demonstrating the usefulness of the simplified criteria in determining optimal designs for on-orbit Space Station identification experiments.

  6. Fluid-Structure Interactions with Flexible and Rigid Bodies

    NASA Astrophysics Data System (ADS)

    Daily, David Jesse

    Fluid structure interactions occur to some extent in nearly every type of fluid flow. Understanding how structures interact with fluids and visa-versa is of vital importance in many engineering applications. The purpose of this research is to explore how fluids interact with flexible and rigid structures. A computational model was used to model the fluid structure interactions of vibrating synthetic vocal folds. The model simulated the coupling of the fluid and solid domains using a fluid-structure interface boundary condition. The fluid domain used a slightly compressible flow solver to allow for the possibility of acoustic coupling with the subglottal geometry and vibration of the vocal fold model. As the subglottis lengthened, the frequency of vibration decreased until a new acoustic mode could form in the subglottis. Synthetic aperture particle image velocimetry (SAPIV) is a three-dimensional particle tracking technique. SAPIV was used to image the jet of air that emerges from vibrating human vocal folds (glottal jet) during phonation. The three-dimensional reconstruction of the glottal jet found faint evidence of flow characteristics seen in previous research, such as axis-switching, but did not have sufficient resolution to detect small features. SAPIV was further applied to reconstruct the smaller flow characteristics of the glottal jet of vibrating synthetic vocal folds. Two- and four-layer synthetic vocal fold models were used to determine how the glottal jet from the synthetic models compared to the glottal jet from excised human vocal folds. The two- and four-layer models clearly exhibited axis-switching which has been seen in other 3D analyses of the glottal jet. Cavitation in a quiescent fluid can break a rigid structure such as a glass bottle. A new cavitation number was derived to include acceleration and pressure head at cavitation onset. A cavitation stick was used to validate the cavitation number by filling it with different depths and hitting

  7. CME Interaction with Large-Scale Coronal Structures

    NASA Technical Reports Server (NTRS)

    Gopalswarny, Nat

    2012-01-01

    This talk presents some key observations that highlight the importance of CME interaction with other large scale structures such as CMEs and coronal holes . Such interactions depend on the phase of the solar cycle: during maximum, CMEs are ejected more frequently, so CME-CME interaction becomes dominant. During the rise phase, the polar coronal holes are strong, so the interaction between polar coronal holes and CMEs is important, which also leads to a possible increase in the number of interplanetary CMEs observed as magnetic clouds. During the declining phase, there are more equatorial coronal holes, so CMEs originating near these coronal holes are easily deflected. CMEs can be deflected toward and away from the Sun-Earth line resulting in interesting geospace consequences. For example, the largest geomagnetic storm of solar cycle 23 was due to a CME that was deflected towards the Sun-earth line from E22. CME deflection away from the Sun-Earth line diminishes the chance of a CME producing a geomagnetic storm. CME interaction in the coronagraphic field of view was first identified using enhanced radio emission, which is an indication of acceleration of low energy (approx.10 keV) electrons in the interaction site. CME interaction, therefore, may also have implications for proton acceleration. For example, solar energetic particle events typically occur with a higher intensity, whenever multiple CMEs occur in quick succession from the same source region. CME deflection may also have implications to the arrival of energetic particles to earth because magnetic connectivity may be changed by the interaction. I illustrate the above points using examples from SOHO, STEREO, Wind, and ACE data .

  8. Characterization of the Structural Features and Interactions of Sclerostin

    PubMed Central

    Veverka, Vaclav; Henry, Alistair J.; Slocombe, Patrick M.; Ventom, Andrew; Mulloy, Barbara; Muskett, Frederick W.; Muzylak, Mariusz; Greenslade, Kevin; Moore, Adrian; Zhang, Li; Gong, Jianhua; Qian, Xueming; Paszty, Chris; Taylor, Richard J.; Robinson, Martyn K.; Carr, Mark D.

    2009-01-01

    The secreted glycoprotein sclerostin has recently emerged as a key negative regulator of Wnt signaling in bone and has stimulated considerable interest as a potential target for therapeutics designed to treat conditions associated with low bone mass, such as osteoporosis. We have determined the structure of sclerostin, which resulted in the identification of a previously unknown binding site for heparin, suggestive of a functional role in localizing sclerostin to the surface of target cells. We have also mapped the interaction site for an antibody that blocks the inhibition of Wnt signaling by sclerostin. This shows minimal overlap with the heparin binding site and highlights a key role for this region of sclerostin in protein interactions associated with the inhibition of Wnt signaling. The conserved N- and C-terminal arms of sclerostin were found to be unstructured, highly flexible, and unaffected by heparin binding, which suggests a role in stabilizing interactions with target proteins. PMID:19208630

  9. Factor selection and structural identification in the interaction ANOVA model.

    PubMed

    Post, Justin B; Bondell, Howard D

    2013-03-01

    When faced with categorical predictors and a continuous response, the objective of an analysis often consists of two tasks: finding which factors are important and determining which levels of the factors differ significantly from one another. Often times, these tasks are done separately using Analysis of Variance (ANOVA) followed by a post hoc hypothesis testing procedure such as Tukey's Honestly Significant Difference test. When interactions between factors are included in the model the collapsing of levels of a factor becomes a more difficult problem. When testing for differences between two levels of a factor, claiming no difference would refer not only to equality of main effects, but also to equality of each interaction involving those levels. This structure between the main effects and interactions in a model is similar to the idea of heredity used in regression models. This article introduces a new method for accomplishing both of the common analysis tasks simultaneously in an interaction model while also adhering to the heredity-type constraint on the model. An appropriate penalization is constructed that encourages levels of factors to collapse and entire factors to be set to zero. It is shown that the procedure has the oracle property implying that asymptotically it performs as well as if the exact structure were known beforehand. We also discuss the application to estimating interactions in the unreplicated case. Simulation studies show the procedure outperforms post hoc hypothesis testing procedures as well as similar methods that do not include a structural constraint. The method is also illustrated using a real data example.

  10. Structural Analysis of Chemokine Receptor-Ligand Interactions.

    PubMed

    Arimont, Marta; Sun, Shan-Liang; Leurs, Rob; Smit, Martine; de Esch, Iwan J P; de Graaf, Chris

    2017-03-10

    This review focuses on the construction and application of structural chemokine receptor models for the elucidation of molecular determinants of chemokine receptor modulation and the structure-based discovery and design of chemokine receptor ligands. A comparative analysis of ligand binding pockets in chemokine receptors is presented, including a detailed description of the CXCR4, CCR2, CCR5, CCR9, and US28 X-ray structures, and their implication for modeling molecular interactions of chemokine receptors with small-molecule ligands, peptide ligands, and large antibodies and chemokines. These studies demonstrate how the integration of new structural information on chemokine receptors with extensive structure-activity relationship and site-directed mutagenesis data facilitates the prediction of the structure of chemokine receptor-ligand complexes that have not been crystallized. Finally, a review of structure-based ligand discovery and design studies based on chemokine receptor crystal structures and homology models illustrates the possibilities and challenges to find novel ligands for chemokine receptors.

  11. Structure of the Interacting Starburst Galaxy II Zw 23

    NASA Astrophysics Data System (ADS)

    Cigan, P. J.; Gallagher, J. S.; Rudie, G.; Wehner, E. H.

    2005-09-01

    II Zw 23 (UGC 3179) is a luminous (MB -21) nearby compact narrow emission line starburst galaxy with blue optical colors and strong emission lines. We present a photometric and morphological study of II Zw 23 and its interacting companion, PC016099, using data obtained with the WIYN 3.5-m telescope in combination with a WFPC2 image from the HST archives. II Zw 23 has a highly disturbed outer structure with long trails of debris that may be feeding tidal dwarfs. Its central regions appear disk-like, a structure that is consistent with the overall rotation pattern observed in the Hα emission line velocity field measured from Densepak observations obtained with WIYN. We discuss these results in terms of the different evolutionary paths followed by stars and gas during strong interactions and the possibility of rapid secondary galactic disk formation in such events.

  12. Primate paternal care: interactions between biology and social experience

    PubMed Central

    Storey, Anne E.; Ziegler, Toni E.

    2016-01-01

    We review recent research on the roles of hormones and social experiences on the development of paternal care in humans and non-human primates. Generally, lower concentrations of testosterone and higher concentrations of oxytocin are associated with greater paternal responsiveness. Hormonal changes prior to the birth appear to be important in preparation for fatherhood and changes after the birth are related to how much time fathers spend with offspring and whether they provide effective care. Prolactin may facilitate approach and the initiation of infant care, and in some biparental non-human primates, it affects body mass regulation. Glucocorticoids are involved in coordinating reproductive and parental behavior between mates. New research involving intranasal oxytocin and neuropeptide receptor polymorphisms may help us understand individual variation in paternal responsiveness. This area of research, integrating both biological factors and the role of early and adult experience, has the potential to suggest individually designed interventions that can strengthen relationships between fathers and their offspring. PMID:26253726

  13. Experiences of using an interactive audience response system in lectures

    PubMed Central

    Uhari, Matti; Renko, Marjo; Soini, Hannu

    2003-01-01

    Background Lectures are good for presenting information and providing explanations, but because they lack active participation they have been neglected. Methods Students' experiences were evaluated after exposing them to the use of voting during lectures in their paediatrics course. Questions were delivered to the students taking paediatrics course. Thirty-six students out of the total of 40 (90%) attended the opening lecture, at which the first survey concerning previous experiences of lectures was performed. Thirty-nine students (98%) answered the second series of questions at the end of the paediatrics course. Results Most of the students felt that voting improved their activity during lectures, enhanced their learning, and that it was easier to make questions during lectures than earlier. Conclusions The students gained new, exciting insights much more often during the paediatrics course than before. We as teachers found that voting during lectures could easily overcome some of the obstacles of good lecturing. PMID:14678571

  14. Relative Displacement Method for Track-Structure Interaction

    PubMed Central

    Ramos, Óscar Ramón; Pantaleón, Marcos J.

    2014-01-01

    The track-structure interaction effects are usually analysed with conventional FEM programs, where it is difficult to implement the complex track-structure connection behaviour, which is nonlinear, elastic-plastic and depends on the vertical load. The authors developed an alternative analysis method, which they call the relative displacement method. It is based on the calculation of deformation states in single DOF element models that satisfy the boundary conditions. For its solution, an iterative optimisation algorithm is used. This method can be implemented in any programming language or analysis software. A comparison with ABAQUS calculations shows a very good result correlation and compliance with the standard's specifications. PMID:24634610

  15. Three-dimensional structural analysis using interactive graphics

    NASA Technical Reports Server (NTRS)

    Biffle, J.; Sumlin, H. A.

    1975-01-01

    The application of computer interactive graphics to three-dimensional structural analysis was described, with emphasis on the following aspects: (1) structural analysis, and (2) generation and checking of input data and examination of the large volume of output data (stresses, displacements, velocities, accelerations). Handling of three-dimensional input processing with a special MESH3D computer program was explained. Similarly, a special code PLTZ may be used to perform all the needed tasks for output processing from a finite element code. Examples were illustrated.

  16. Inferring the structure and dynamics of interactions in schooling fish

    PubMed Central

    Katz, Yael; Tunstrøm, Kolbjørn; Ioannou, Christos C.; Huepe, Cristián; Couzin, Iain D.

    2011-01-01

    Determining individual-level interactions that govern highly coordinated motion in animal groups or cellular aggregates has been a long-standing challenge, central to understanding the mechanisms and evolution of collective behavior. Numerous models have been proposed, many of which display realistic-looking dynamics, but nonetheless rely on untested assumptions about how individuals integrate information to guide movement. Here we infer behavioral rules directly from experimental data. We begin by analyzing trajectories of golden shiners (Notemigonus crysoleucas) swimming in two-fish and three-fish shoals to map the mean effective forces as a function of fish positions and velocities. Speeding and turning responses are dynamically modulated and clearly delineated. Speed regulation is a dominant component of how fish interact, and changes in speed are transmitted to those both behind and ahead. Alignment emerges from attraction and repulsion, and fish tend to copy directional changes made by those ahead. We find no evidence for explicit matching of body orientation. By comparing data from two-fish and three-fish shoals, we challenge the standard assumption, ubiquitous in physics-inspired models of collective behavior, that individual motion results from averaging responses to each neighbor considered separately; three-body interactions make a substantial contribution to fish dynamics. However, pairwise interactions qualitatively capture the correct spatial interaction structure in small groups, and this structure persists in larger groups of 10 and 30 fish. The interactions revealed here may help account for the rapid changes in speed and direction that enable real animal groups to stay cohesive and amplify important social information. PMID:21795604

  17. Deciphering Supramolecular Structures with Protein-Protein Interaction Network Modeling

    PubMed Central

    Tsuji, Toshiyuki; Yoda, Takao; Shirai, Tsuyoshi

    2015-01-01

    Many biological molecules are assembled into supramolecules that are essential to perform complicated functions in the cell. However, experimental information about the structures of supramolecules is not sufficient at this point. We developed a method of predicting and modeling the structures of supramolecules in a biological network by combining structural data of the Protein Data Bank (PDB) and interaction data in IntAct databases. Templates for binary complexes in IntAct were extracted from PDB. Modeling was attempted by assembling binary complexes with superposed shared subunits. A total of 3,197 models were constructed, and 1,306 (41% of the total) contained at least one subunit absent from experimental structures. The models also suggested 970 (25% of the total) experimentally undetected subunit interfaces, and 41 human disease-related amino acid variants were mapped onto these model-suggested interfaces. The models demonstrated that protein-protein interaction network modeling is useful to fill the information gap between biological networks and structures. PMID:26549015

  18. High frequency flow-structural interaction in dense subsonic fluids

    NASA Technical Reports Server (NTRS)

    Liu, Baw-Lin; Ofarrell, J. M.

    1995-01-01

    Prediction of the detailed dynamic behavior in rocket propellant feed systems and engines and other such high-energy fluid systems requires precise analysis to assure structural performance. Designs sometimes require placement of bluff bodies in a flow passage. Additionally, there are flexibilities in ducts, liners, and piping systems. A design handbook and interactive data base have been developed for assessing flow/structural interactions to be used as a tool in design and development, to evaluate applicable geometries before problems develop, or to eliminate or minimize problems with existing hardware. This is a compilation of analytical/empirical data and techniques to evaluate detailed dynamic characteristics of both the fluid and structures. These techniques have direct applicability to rocket engine internal flow passages, hot gas drive systems, and vehicle propellant feed systems. Organization of the handbook is by basic geometries for estimating Strouhal numbers, added mass effects, mode shapes for various end constraints, critical onset flow conditions, and possible structural response amplitudes. Emphasis is on dense fluids and high structural loading potential for fatigue at low subsonic flow speeds where high-frequency excitations are possible. Avoidance and corrective measure illustrations are presented together with analytical curve fits for predictions compiled from a comprehensive data base.

  19. Genetics-based interactions among plants, pathogens, and herbivores define arthropod community structure.

    PubMed

    Busby, Posy E; Lamit, Louis J; Keith, Arthur R; Newcombe, George; Gehring, Catherine A; Whitham, Thomas G; Dirzo, Rodolfo

    2015-07-01

    Plant resistance to pathogens or insect herbivores is common, but its potential for indirectly influencing plant-associated communities is poorly known. Here, we test whether pathogens' indirect effects on arthropod communities and herbivory depend on plant resistance to pathogens and/or herbivores, and address the overarching interacting foundation species hypothesis that genetics-based interactions among a few highly interactive species can structure a much larger community. In a manipulative field experiment using replicated genotypes of two Populus species and their interspecific hybrids, we found that genetic variation in plant resistance to both pathogens and insect herbivores modulated the strength of pathogens' indirect effects on arthropod communities and insect herbivory. First, due in part to the pathogens' differential impacts on leaf biomass among the two Populus species and the hybrids, the pathogen most strongly impacted arthropod community composition, richness, and abundance on the pathogen-susceptible tree species. Second, we found similar patterns comparing pathogen-susceptible and pathogen-resistant genotypes within species. Third, within a plant species, pathogens caused a fivefold greater reduction in herbivory on insect-herbivore-susceptible plant genotypes than on herbivore-resistant genotypes, demonstrating that the pathogen-herbivore interaction is genotype dependent. We conclude that interactions among plants, pathogens, and herbivores can structure multitrophic communities, supporting the interacting foundation species hypothesis. Because these interactions are genetically based, evolutionary changes in genetic resistance could result in ecological changes in associated communities, which may in turn feed back to affect plant fitness.

  20. Cross-Modal Interactions in the Experience of Musical Performances: Physiological Correlates

    ERIC Educational Resources Information Center

    Chapados, Catherine; Levitin, Daniel J.

    2008-01-01

    This experiment was conducted to investigate cross-modal interactions in the emotional experience of music listeners. Previous research showed that visual information present in a musical performance is rich in expressive content, and moderates the subjective emotional experience of a participant listening and/or observing musical stimuli [Vines,…

  1. Structure of colloidosomes with tunable particle density: Simulation versus experiment

    NASA Astrophysics Data System (ADS)

    Fantoni, Riccardo; Salari, Johannes W. O.; Klumperman, Bert

    2012-06-01

    Colloidosomes are created in the laboratory from a Pickering emulsion of water droplets in oil. The colloidosomes have approximately the same diameter and by choosing (hairy) particles of different diameters it is possible to control the particle density on the droplets. The experiment is performed at room temperature. The radial distribution function of the assembly of (primary) particles on the water droplet is measured in the laboratory and in a computer experiment of a fluid model of particles with pairwise interactions on the surface of a sphere.

  2. Solid breeder/structure mechanical interaction and thermal stability

    SciTech Connect

    Liu, Y.Y.; Billone, M.C.; Taghavi, K.

    1985-04-01

    Solid breeder/structure mechanical interaction (BSMI) during fusion reactor blanket operation is a potential failure mode which could limit the lifetime of the blanket. The severity of BSMI will generally depend on the materials, specific blanket designs, and blanket operating conditions. Thermomechanical analyses performed for a helium-cooled blanket employing Li/sub 2/O/HT-9 plates indicate that BSMI could be a serious concern for this blanket.

  3. Computational Study of Colloidal Droplet Interactions with Three Dimensional Structures

    DTIC Science & Technology

    2015-05-18

    SECURITY CLASSIFICATION OF: The colloidal droplet spreading on and sorption into a porous medium is important to 3D printing technology. In this study... colloidal fluid distribution in the porous structure after sorption of single/multiple droplets in powder beds. The spreading of the droplet on the surface...Feb-2015 Approved for Public Release; Distribution Unlimited Final Report: Computational Study of Colloidal Droplet Interactions with Three Dimensional

  4. Fundamentals of Magnetic Interactions: New Approaches to Theory and Experiment.

    DTIC Science & Technology

    1981-08-01

    spinel crystal structure. The primitive cell has lattice parameter a and contains two formula units. The large open and large flecked circles are Cd or... primitive cell has lattice parameter a and contains two formula units. The large open and large flecked circles are Cd or Hg; filled-in and small flecked

  5. Diversifying Science: Underrepresented Student Experiences in Structured Research Programs

    PubMed Central

    Cabrera, Nolan L.; Lin, Monica H.; Arellano, Lucy; Espinosa, Lorelle L.

    2013-01-01

    Targeting four institutions with structured science research programs for undergraduates, this study focuses on how underrepresented students experience science. Several key themes emerged from focus group discussions: learning to become research scientists, experiences with the culture of science, and views on racial and social stigma. Participants spoke of essential factors for becoming a scientist, but their experiences also raised complex issues about the role of race and social stigma in scientific training. Students experienced the collaborative and empowering culture of science, exhibited strong science identities and high self-efficacy, while developing directed career goals as a result of “doing science” in these programs. PMID:23503690

  6. Three Slit Experiments and the Structure of Quantum Theory

    NASA Astrophysics Data System (ADS)

    Ududec, Cozmin; Barnum, Howard; Emerson, Joseph

    2011-03-01

    In spite of the interference manifested in the double-slit experiment, quantum theory predicts that a measure of interference defined by Sorkin and involving various outcome probabilities from an experiment with three slits, is identically zero. We adapt Sorkin's measure into a general operational probabilistic framework for physical theories, and then study its relationship to the structure of quantum theory. In particular, we characterize the class of probabilistic theories for which the interference measure is zero as ones in which it is possible to fully determine the state of a system via specific sets of `two-slit' experiments.

  7. Flavonoid interactions with human transthyretin: combined structural and thermodynamic analysis.

    PubMed

    Trivella, Daniela B B; dos Reis, Caio V; Lima, Luís Maurício T R; Foguel, Débora; Polikarpov, Igor

    2012-10-01

    Transthyretin (TTR) is a carrier protein involved in human amyloidosis. The development of small molecules that may act as TTR amyloid inhibitors is a promising strategy to treat these pathologies. Here we selected and characterized the interaction of flavonoids with the wild type and the V30M amyloidogenic mutant TTR. TTR acid aggregation was evaluated in vitro in the presence of the different flavonoids. The best TTR aggregation inhibitors were studied by Isothermal Titration Calorimetry (ITC) in order to reveal their thermodynamic signature of binding to TTRwt. Crystal structures of TTRwt in complex with the top binders were also obtained, enabling us to in depth inspect TTR interactions with these flavonoids. The results indicate that changing the number and position of hydroxyl groups attached to the flavonoid core strongly influence flavonoid recognition by TTR, either by changing ligand affinity or its mechanism of interaction with the two sites of TTR. We also compared the results obtained for TTRwt with the V30M mutant structure in the apo form, allowing us to pinpoint structural features that may facilitate or hamper ligand binding to the V30M mutant. Our data show that the TTRwt binding site is labile and, in particular, the central region of the cavity is sensible for the small differences in the ligands tested and can be influenced by the Met30 amyloidogenic mutation, therefore playing important roles in flavonoid binding affinity, mechanism and mutant protein ligand binding specificities.

  8. Coupling fluid-structure interaction with phase-field fracture

    NASA Astrophysics Data System (ADS)

    Wick, Thomas

    2016-12-01

    In this work, a concept for coupling fluid-structure interaction with brittle fracture in elasticity is proposed. The fluid-structure interaction problem is modeled in terms of the arbitrary Lagrangian-Eulerian technique and couples the isothermal, incompressible Navier-Stokes equations with nonlinear elastodynamics using the Saint-Venant Kirchhoff solid model. The brittle fracture model is based on a phase-field approach for cracks in elasticity and pressurized elastic solids. In order to derive a common framework, the phase-field approach is re-formulated in Lagrangian coordinates to combine it with fluid-structure interaction. A crack irreversibility condition, that is mathematically characterized as an inequality constraint in time, is enforced with the help of an augmented Lagrangian iteration. The resulting problem is highly nonlinear and solved with a modified Newton method (e.g., error-oriented) that specifically allows for a temporary increase of the residuals. The proposed framework is substantiated with several numerical tests. In these examples, computational stability in space and time is shown for several goal functionals, which demonstrates reliability of numerical modeling and algorithmic techniques. But also current limitations such as the necessity of using solid damping are addressed.

  9. The structure and interactions of starch with food constituents.

    PubMed

    Biliaderis, C G

    1991-01-01

    For most starch-containing foods, the physical and functional properties can be traced to characteristic molecular species being present, their interactions with each other, and modifications caused by environmental conditions (moisture, temperature, shear) during processing and storage. In the present paper, the chemistry and physical chemistry of starch are discussed with an emphasis on how structure (molecular and supermolecular) and composition influence the functionality of this polysaccharide. New experimental findings brought forward on structure indicate that this polymeric carbohydrate is found in various metastable states, depending on the thermomechanical history of the product. Even more important to processing and quality attributes of starch products is the recognition that the dynamics of the supermolecular structure and interactions between starch and other food constituents are governed by the mobility of the amorphous phase of each particular system. In this respect, water, acting as a plasticizer, depresses the glass transition temperature (Tg) and thereby alters the kinetics of state transformations (e.g., gelatinization, retrogradation) and reactivity of starch. The effects of water on phase transition behavior of starch as well as the underlying molecular mechanisms to the phenomena of gelatinization, gelation, retrogradation, and starch-lipid interactions are reviewed herein. Finally, consideration is given to factors affecting the digestibility of starch from the viewpoint of processing-related changes in the susceptibility of starch to alpha-amylase.

  10. The Accelerator Neutrino Neutron Interaction Experiment (ANNIE) Front Anti-Coincidence Counter (FACC) Testing

    NASA Astrophysics Data System (ADS)

    Chen, Mingqian

    The searching for proton decay (PDK) is going on current Water Cherenkov (WCh) detectors such as Super-Kamiokande. However, PDK-like backgrounds produced by the neutrino interactions will limit the sensitivity of the detectors. The Accelerator Neutrino Neutron Interaction Experiment (ANNIE) is going to measure the neutron yield of neutrino interactions in gadolinium-loaded water by the Booster Neutrino Beam (BNB) with known characteristics. In this thesis, neutrino, neutrino oscillations, Dirac neutrino and Majorana neutrino and neutrino interactions are introduced. ANNIE experiment is also introduced. And two modes of proton decays are discussed. The ANNIE experiment requires detection of the neutrons produced by the BNB interactions with water. However, dirt muons produced by the interaction of the BNB with the rock and dirt upstream of the ANNIE hall will cause a correlated background. Therefore, the Front Anti-Coincidence Counter (FACC) was built to measure the rock muons. This thesis details the design, installation, and commissioning of the ANNIE FACC.

  11. Dynamic near-field optical interaction between oscillating nanomechanical structures

    SciTech Connect

    Ahn, Phillip; Chen, Xiang; Zhang, Zhen; Ford, Matthew; Rosenmann, Daniel; Jung, II Woong; Sun, Cheng; Balogun, Oluwaseyi

    2015-05-27

    Near-field optical techniques exploit light-matter interactions at small length scales for mechanical sensing and actuation of nanomechanical structures. Here, we study the optical interaction between two mechanical oscillators—a plasmonic nanofocusing probe-tip supported by a low frequency cantilever, and a high frequency nanomechanical resonator—and leverage their interaction for local detection of mechanical vibrations. The plasmonic nanofocusing probe provides a confined optical source to enhance the interaction between the two oscillators. Dynamic perturbation of the optical cavity between the probe-tip and the resonator leads to nonlinear modulation of the scattered light intensity at the sum and difference of their frequencies. This double-frequency demodulation scheme is explored to suppress unwanted background and to detect mechanical vibrations with a minimum detectable displacement sensitivity of 0.45pm/Hz1/2, which is limited by shot noise and electrical noise. We explore the demodulation scheme for imaging the bending vibration mode shape of the resonator with a lateral spatial resolution of 20nm. We also demonstrate the time-resolved aspect of the local optical interaction by recording the ring-down vibrations of the resonator at frequencies of up to 129MHz. The near-field optical technique is promising for studying dynamic mechanical processes in individual nanostructures.

  12. Dynamic near-field optical interaction between oscillating nanomechanical structures

    DOE PAGES

    Ahn, Phillip; Chen, Xiang; Zhang, Zhen; ...

    2015-05-27

    Near-field optical techniques exploit light-matter interactions at small length scales for mechanical sensing and actuation of nanomechanical structures. Here, we study the optical interaction between two mechanical oscillators—a plasmonic nanofocusing probe-tip supported by a low frequency cantilever, and a high frequency nanomechanical resonator—and leverage their interaction for local detection of mechanical vibrations. The plasmonic nanofocusing probe provides a confined optical source to enhance the interaction between the two oscillators. Dynamic perturbation of the optical cavity between the probe-tip and the resonator leads to nonlinear modulation of the scattered light intensity at the sum and difference of their frequencies. This double-frequencymore » demodulation scheme is explored to suppress unwanted background and to detect mechanical vibrations with a minimum detectable displacement sensitivity of 0.45pm/Hz1/2, which is limited by shot noise and electrical noise. We explore the demodulation scheme for imaging the bending vibration mode shape of the resonator with a lateral spatial resolution of 20nm. We also demonstrate the time-resolved aspect of the local optical interaction by recording the ring-down vibrations of the resonator at frequencies of up to 129MHz. The near-field optical technique is promising for studying dynamic mechanical processes in individual nanostructures.« less

  13. Dynamic near-field optical interaction between oscillating nanomechanical structures

    PubMed Central

    Ahn, Phillip; Chen, Xiang; Zhang, Zhen; Ford, Matthew; Rosenmann, Daniel; Jung, II Woong; Sun, Cheng; Balogun, Oluwaseyi

    2015-01-01

    Near-field optical techniques exploit light-matter interactions at small length scales for mechanical sensing and actuation of nanomechanical structures. Here, we study the optical interaction between two mechanical oscillators—a plasmonic nanofocusing probe-tip supported by a low frequency cantilever, and a high frequency nanomechanical resonator—and leverage their interaction for local detection of mechanical vibrations. The plasmonic nanofocusing probe provides a confined optical source to enhance the interaction between the two oscillators. Dynamic perturbation of the optical cavity between the probe-tip and the resonator leads to nonlinear modulation of the scattered light intensity at the sum and difference of their frequencies. This double-frequency demodulation scheme is explored to suppress unwanted background and to detect mechanical vibrations with a minimum detectable displacement sensitivity of 0.45 pm/Hz1/2, which is limited by shot noise and electrical noise. We explore the demodulation scheme for imaging the bending vibration mode shape of the resonator with a lateral spatial resolution of 20 nm. We also demonstrate the time-resolved aspect of the local optical interaction by recording the ring-down vibrations of the resonator at frequencies of up to 129 MHz. The near-field optical technique is promising for studying dynamic mechanical processes in individual nanostructures. PMID:26014599

  14. Structured learning of human interactions in TV shows.

    PubMed

    Patron-Perez, Alonso; Marszalek, Marcin; Reid, Ian; Zisserman, Andrew

    2012-12-01

    The objective of this work is recognition and spatiotemporal localization of two-person interactions in video. Our approach is person-centric. As a first stage we track all upper bodies and heads in a video using a tracking-by-detection approach that combines detections with KLT tracking and clique partitioning, together with occlusion detection, to yield robust person tracks. We develop local descriptors of activity based on the head orientation (estimated using a set of pose-specific classifiers) and the local spatiotemporal region around them, together with global descriptors that encode the relative positions of people as a function of interaction type. Learning and inference on the model uses a structured output SVM which combines the local and global descriptors in a principled manner. Inference using the model yields information about which pairs of people are interacting, their interaction class, and their head orientation (which is also treated as a variable, enabling mistakes in the classifier to be corrected using global context). We show that inference can be carried out with polynomial complexity in the number of people, and describe an efficient algorithm for this. The method is evaluated on a new dataset comprising 300 video clips acquired from 23 different TV shows and on the benchmark UT--Interaction dataset.

  15. Structure and thermodynamic properties of water-methanol mixtures: Role of the water-water interaction

    NASA Astrophysics Data System (ADS)

    Tanaka, Hideki; Gubbins, Keith E.

    1992-08-01

    Thermodynamic properties and structures of water-methanol mixtures at various temperatures have been investigated by means of Monte Carlo simulations and subsequent analyses. The OPLS model by Jorgensen was used for the methanol-methanol interaction and both the Caravetta-Clementi (CC) potential and TIP4P potential by Jorgensen et al. were used for the water-water interaction. We show that the role of water-water interaction is very important in discussing aqueous solutions of alcohols, and examine the origin of the exothermic mixing processes. We have investigated the sensitivity of the temperature dependence of the enthalpy of mixing to the water-water interaction. The CC potential is able to reproduce the temperature dependence observed in experiments, although the absolute values of the mixing enthalpy were larger than the experimental ones. While the TIP4P potential results in better agreement for the excess enthalpy and volume near room temperature, the temperature dependence of the excess enthalpy did not agree with experiment. The difference in the magnitude of the exothermic hydration for different water-water interactions is explained in terms of the energetic stability of the clathrate hydrate compared with ice, on the basis that the structure of water in the vicinity of a methanol molecule is similar to the clathrate hydrate. It is found that the energetic stability of the clathrate hydrate for the CC model is higher than that for TIP4P, and this is responsible for the larger exothermic hydration. The higher stability of the clathrate hydrate structure for the CC potential, in turn, arises from the difference in the pair interaction energy surface between two kinds of potential functions; the minimum energy structure and the flexibility of the hydrogen bonded pair.

  16. Structure and thermodynamic properties of water--methanol mixtures: Role of the water--water interaction

    SciTech Connect

    Tanaka, H. ); Gubbins, K.E. )

    1992-08-15

    Thermodynamic properties and structures of water--methanol mixtures at various temperatures have been investigated by means of Monte Carlo simulations and subsequent analyses. The OPLS model by Jorgensen was used for the methanol--methanol interaction and both the Caravetta--Clementi (CC) potential and TIP4P potential by Jorgensen {ital et} {ital al}. were used for the water--water interaction. We show that the role of water--water interaction is very important in discussing aqueous solutions of alcohols, and examine the origin of the exothermic mixing processes. We have investigated the sensitivity of the temperature dependence of the enthalpy of mixing to the water--water interaction. The CC potential is able to reproduce the temperature dependence observed in experiments, although the absolute values of the mixing enthalpy were larger than the experimental ones. While the TIP4P potential results in better agreement for the excess enthalpy and volume near room temperature, the temperature dependence of the excess enthalpy did not agree with experiment. The difference in the magnitude of the exothermic hydration for different water--water interactions is explained in terms of the energetic stability of the clathrate hydrate compared with ice, on the basis that the structure of water in the vicinity of a methanol molecule is similar to the clathrate hydrate. It is found that the energetic stability of the clathrate hydrate for the CC model is higher than that for TIP4P, and this is responsible for the larger exothermic hydration. The higher stability of the clathrate hydrate structure for the CC potential, in turn, arises from the difference in the pair interaction energy surface between two kinds of potential functions; the minimum energy structure and the flexibility of the hydrogen bonded pair.

  17. The effect of an interactive experience on music majors' perceptions of music for deaf students.

    PubMed

    Kaiser, K A; Johnson, K E

    2000-01-01

    The purpose of this study was to examine the effect of an interactive experience on music majors' perceptions of music experiences for deaf students. Twenty-three members of a pre-existing college brass ensemble served as subjects, and a 1-hour interactive concert/presentation for 10 deaf elementary children served as the independent variable. The interactive experience was designed to provide social, musical, and educational interactions between the college musicians and the deaf children. A pretest-posttest design was utilized, and the dependent variable was a questionnaire designed to examine the subjects' perceptions regarding music for deaf students, including how prepared, comfortable, and willing they felt to provide music experiences for deaf students. Results reveal that this single interactive experience had a significant effect on the subjects' perceptions of the value of music in the education of deaf children (p <.05). Although the pretest and posttest scores indicate that the subjects felt apprehensive about their preparedness to work with deaf students, the subjects felt significantly more positive about their preparedness following the interaction (p <.001). An analysis of open comments indicates that the subjects perceived the experience as (a) very positive, (b) increasing their knowledge and perception of music for deaf students, (c) helping them better relate to the deaf population, (d) promoting interest in similar experiences and in gaining more information, and (e) eliciting a feeling that future teachers should have similar experiences. Quotes from the subjects are given, and implications for teacher training/music therapy programs are discussed.

  18. Modeling Gene-Environment Interactions With Quasi-Natural Experiments.

    PubMed

    Schmitz, Lauren; Conley, Dalton

    2017-02-01

    This overview develops new empirical models that can effectively document Gene × Environment (G×E) interactions in observational data. Current G×E studies are often unable to support causal inference because they use endogenous measures of the environment or fail to adequately address the nonrandom distribution of genes across environments, confounding estimates. Comprehensive measures of genetic variation are incorporated into quasi-natural experimental designs to exploit exogenous environmental shocks or isolate variation in environmental exposure to avoid potential confounders. In addition, we offer insights from population genetics that improve upon extant approaches to address problems from population stratification. Together, these tools offer a powerful way forward for G×E research on the origin and development of social inequality across the life course.

  19. Magnetised bow shocks and oblique shock interactions: HEDLA experiments on the Magpie pulsed-power facility

    NASA Astrophysics Data System (ADS)

    Burdiak, G. C.; Lebedev, S. V.; Chittenden, J. P.; Clayson, T.; Garcia, C.; Hare, J. D.; Niasse, N.; Suttle, L. G.; Suzuki-Vidal, F.; Frank, A.; Ciardi, A.

    2016-10-01

    We present results from magnetised shock experiments performed on the Magpie ( 1 MA, 250 ns) pulsed-power facility. Shocks are formed around cylindrical and oblique planar obstacles positioned in a supersonic, super-Alfvenic plasma flow (MS = 5 , MA = 2.5 , vf = 70 km/s). The plasma flow is produced by an inverse, exploding wire array z-pinch and carries an embedded magnetic field that is well frozen in (ReM = 20). We show how the structure of bow and oblique shocks is dramatically affected by the orientation of the advected magnetic field with respect to the obstacles. More complex obstacle geometries allow us to study the interaction of multiple magnetised oblique shocks. These systems can cause the annihilation of magnetic flux and the generation of shear flow along a slip layer. Work supported by DOE cooperative agreements No. DE-F03- 02NA00057 and No. DE-SC-0001063.

  20. Interaction strength and model geometry effects on the structure of crossing-shock wave/turbulent boundary-layer interactions

    NASA Technical Reports Server (NTRS)

    Garrison, T. J.; Settles, G. S.

    1993-01-01

    The flowfield structure of a range of symmetric crossing-shock wave/turbulent boundary-layer interactions of varying strength is presented. The test geometry, consisting of a symmetric pair of opposing sharp fins at angle of attack, alpha, mounted to a flat plate, is studied experimentally for a range of alpha from 7 to 15 degrees at Mach numbers of 3 and 4. Results reveal that the basic flowfield shock structure remains similar in nature over the range of interaction strengths examined, with the only changes being in the scale and location of the various features present. The separated flow regions are classified as being either completely or partially separated, the completely separated case being the one in which the entire incoming boundary layer separates from the plate surface. For the current experiments, all but the weakest of the interactions exhibited complete boundary layer separation. Finally, the effects of model geometry are analyzed by comparing data for shock generators of varying lengths, with the results showing no evidence of upstream influence due to the shock generator trailing edges.

  1. Front surface structured targets for enhancing laser-plasma interactions

    NASA Astrophysics Data System (ADS)

    Snyder, Joseph; George, Kevin; Ji, Liangliang; Yalamanchili, Sasir; Simonoff, Ethan; Cochran, Ginevra; Daskalova, Rebecca; Poole, Patrick; Willis, Christopher; Lewis, Nathan; Schumacher, Douglass

    2016-10-01

    We present recent progress made using front surface structured interfaces for enhancing ultrashort, relativistic laser-plasma interactions. Structured targets can increase laser absorption and enhance ion acceleration through a number of mechanisms such as direct laser acceleration and laser guiding. We detail experimental results obtained at the Scarlet laser facility on hollow, micron-scale plasma channels for enhancing electron acceleration. These targets show a greater than three times enhancement in the electron cutoff energy as well as an increased slope temperature for the electron distribution when compared to a flat interface. Using three-dimensional particle-in-cell (PIC) simulations, we have modeled the interaction to give insight into the physical processes responsible for the enhancement. Furthermore, we have used PIC simulations to design structures that are more advantageous for ion acceleration. Such targets necessitate advanced target fabrication methods and we describe techniques used to manufacture optimized structures, including vapor-liquid-solid growth, cryogenic etching, and 3D printing using two-photon-polymerization. This material is based upon work supported by the Air Force Office of Scientific Research under Award Number FA9550-14-1-0085.

  2. Generation of filamentary structures by beam-plasma interaction

    SciTech Connect

    Wang, X.Y.; Lin, Y.

    2006-05-15

    The previous simulations by Wang and Lin [Phys. Plasmas. 10, 3528 (2003)] showed that filaments, frequently observed in space plasmas, can form via the interaction between an ion beam and a background plasma. In this study, the physical mechanism for the generation of the filaments is investigated by a two-dimensional hybrid simulation, in which a field-aligned ion beam with relative beam density n{sub b}=0.1 and beam velocity V{sub b}=10V{sub A} is initiated in a uniform plasma. Right-hand nonresonant ion beam modes, consistent with the linear theory, are found to be dominant in the linear stage of the beam-plasma interaction. In the later nonlinear stage, the nonresonant modes decay and the resonant modes grow through a nonlinear wave coupling. The interaction among the resonant modes leads to the formation of filamentary structures, which are the field-aligned structures (k perpendicular B) of magnetic field B, density, and temperature in the final stage. The filaments are nonlinearly generated in a prey-predator fashion by the parallel and oblique resonant ion beam modes, which meanwhile evolve into two types of shear Alfven modes, with one mainly propagating along the background field B{sub 0} and the other obliquely propagating. The filamentary structures are found to be phase standing in the plasma frame, but their amplitude oscillates with time. In the dominant filament mode, fluctuations in the background ion density, background ion temperature, and beam density are in phase with the fluctuations in B, whereas the significantly enhanced beam temperature is antiphase with B. It is found that the filaments are produced by the interaction of at least two ion beam modes with comparable amplitudes, not by only one single mode, thus their generation mechanism is different from other mechanisms such as the stimulated excitation by the decay of an Alfven wave.

  3. Causal inference and the hierarchical structure of experience

    PubMed Central

    Johnson, Samuel G. B.; Keil, Frank C.

    2014-01-01

    Children and adults make rich causal inferences about the physical and social world, even in novel situations where they cannot rely on prior knowledge of causal mechanisms. We propose that this capacity is supported in part by constraints provided by event structure—the cognitive organization of experience into discrete events that are hierarchically organized. These event-structured causal inferences are guided by a level-matching principle, with events conceptualized at one level of an event hierarchy causally matched to other events at that same level, and a boundary-blocking principle, with events causally matched to other events that are parts of the same superordinate event. These principles are used to constrain inferences about plausible causal candidates in unfamiliar situations, both in diagnosing causes (Experiment 1) and predicting effects (Experiment 2). The results could not be explained by construal level (Experiment 3) or similarity-matching (Experiment 4), and were robust across a variety of physical and social causal systems. Taken together, these experiments demonstrate a novel way in which non-causal information we extract from the environment can help to constrain inferences about causal structure. PMID:25347533

  4. Structural correlations in diffusiophoretic colloidal mixtures with nonreciprocal interactions.

    PubMed

    Bartnick, Jörg; Heinen, Marco; Ivlev, Alexei V; Löwen, Hartmut

    2016-01-20

    Nonreciprocal effective interaction forces can occur between mesoscopic particles in colloidal suspensions that are driven out of equilibrium. These forces violate Newton's third law actio  =  reactio on coarse-grained length and time scales. Here we explore the statistical mechanics of Brownian particles with nonreciprocal effective interactions. Our model system is a binary fluid mixture of spherically symmetric, diffusiophoretic mesoscopic particles, and we focus on the time-averaged particle pair- and triplet-correlation functions. Based on the many-body Smoluchowski equation we develop a microscopic statistical theory for the particle correlations and test it by computer simulations. For model systems in two and three spatial dimensions, we show that nonreciprocity induces distinct nonequilibrium pair correlations. Our predictions can be tested in experiments with chemotactic colloidal suspensions.

  5. Shock-driven fluid-structure interaction for civil design

    SciTech Connect

    Wood, Stephen L; Deiterding, Ralf

    2011-11-01

    The multiphysics fluid-structure interaction simulation of shock-loaded structures requires the dynamic coupling of a shock-capturing flow solver to a solid mechanics solver for large deformations. The Virtual Test Facility combines a Cartesian embedded boundary approach with dynamic mesh adaptation in a generic software framework of flow solvers using hydrodynamic finite volume upwind schemes that are coupled to various explicit finite element solid dynamics solvers (Deiterding et al., 2006). This paper gives a brief overview of the computational approach and presents first simulations that utilize the general purpose solid dynamics code DYNA3D for complex 3D structures of interest in civil engineering. Results from simulations of a reinforced column, highway bridge, multistory building, and nuclear reactor building are presented.

  6. Isotope labeling for NMR studies of macromolecular structure and interactions

    SciTech Connect

    Wright, P.E.

    1994-12-01

    Implementation of biosynthetic methods for uniform or specific isotope labeling of proteins, coupled with the recent development of powerful heteronuclear multidimensional NMR methods, has led to a dramatic increase in the size and complexity of macromolecular systems that are now amenable to NMR structural analysis. In recent years, a new technology has emerged that combines uniform {sup 13}C, {sup 15}N labeling with heteronuclear multidimensional NMR methods to allow NMR structural studies of systems approaching 25 to 30 kDa in molecular weight. In addition, with the introduction of specific {sup 13}C and {sup 15}N labels into ligands, meaningful NMR studies of complexes of even higher molecular weight have become feasible. These advances usher in a new era in which the earlier, rather stringent molecular weight limitations have been greatly surpassed and NMR can begin to address many central biological problems that involve macromolecular structure, dynamics, and interactions.

  7. Finite element solution of transient fluid-structure interaction problems

    NASA Technical Reports Server (NTRS)

    Everstine, Gordon C.; Cheng, Raymond S.; Hambric, Stephen A.

    1991-01-01

    A finite element approach using NASTRAN is developed for solving time-dependent fluid-structure interaction problems, with emphasis on the transient scattering of acoustic waves from submerged elastic structures. Finite elements are used for modeling both structure and fluid domains to facilitate the graphical display of the wave motion through both media. For the liquid, the use of velocity potential as the fundamental unknown results in a symmetric matrix equation. The approach is illustrated for the problem of transient scattering from a submerged elastic spherical shell subjected to an incident tone burst. The use of an analogy between the equations of elasticity and the wave equation of acoustics, a necessary ingredient to the procedure, is summarized.

  8. Experience-dependent structural synaptic plasticity in the mammalian brain.

    PubMed

    Holtmaat, Anthony; Svoboda, Karel

    2009-09-01

    Synaptic plasticity in adult neural circuits may involve the strengthening or weakening of existing synapses as well as structural plasticity, including synapse formation and elimination. Indeed, long-term in vivo imaging studies are beginning to reveal the structural dynamics of neocortical neurons in the normal and injured adult brain. Although the overall cell-specific morphology of axons and dendrites, as well as of a subpopulation of small synaptic structures, are remarkably stable, there is increasing evidence that experience-dependent plasticity of specific circuits in the somatosensory and visual cortex involves cell type-specific structural plasticity: some boutons and dendritic spines appear and disappear, accompanied by synapse formation and elimination, respectively. This Review focuses on recent evidence for such structural forms of synaptic plasticity in the mammalian cortex and outlines open questions.

  9. Simulation of the photogrammetric appendage structural dynamics experiment

    NASA Technical Reports Server (NTRS)

    Pappa, Richard S.; Gilbert, Michael G.; Welch, Sharon S.

    1995-01-01

    The Photogrammetric Appendage Structural Dynamics Experiment (PASDE) uses six video cameras in the Space Shuttle cargo bay to measure vibration of the Russian Mir space station Kvant-ll solar array. It occurs on Shuttle/Mir docking mission STS-74 scheduled for launch in November 1995. The objective of PASDE is to demonstrate photogrammetric technology for measuring 'untargeted' spacecraft appendage structural dynamics. This paper discusses a pre-flight simulation test conducted in July 1995, focusing on the image processing aspects. The flight camera system recorded vibrations of a full-scale structural test article having grids of white lines on black background, similar in appearance to the Mir solar array. Using image correlation analysis, line intersections on the structure are tracked in the video recordings to resolutions of less than 0.1 pixel. Calibration and merging of multiple camera views generated 3-dimensional displacements from which structural modal parameters are then obtained.

  10. Wave-current interaction, experiments with controlled uniform shear

    NASA Astrophysics Data System (ADS)

    Simon, Bruno; Touboul, Julien; Rey, Vincent

    2016-04-01

    Vertically varying currents have a non negligible impact on the propagation of waves. Even though the analytical aspect of the interaction between wave and sheared current is being an active subject of research, experimental data remain rare. Here, the effects of a uniformly shear were investigated in the 10 m long by 0.3 m wide wave flume of the Université de Toulon, France. The main difficulty of the study was to produce several conditions of current with constant shear (du/dz = cst) that would persist along the channel. This was achieved by using curved wire screens upstream the channel (Dunn and Tavoularis, 2007). The geometry and properties of the screens were adjusted to deflect the streamline towards the channel bed or the free surface in order to change the velocity profile. The study focused on regular wave propagating against the current for several wave frequencies and amplitudes. Properties of the free surface and flow velocity are discussed for current with positive and negative shear in order to quantify the influence of the current on the waves. ACKNOWLEDGEMENTS The DGA (Direction Générale de l'Armement, France) is acknowledged for its financial support through the ANR grant N° ANR-13-ASTR-0007.

  11. Communication and laboratory performance in parapsychology experiments: demand characteristics and the social organization of interaction.

    PubMed

    Wooffitt, Robin

    2007-09-01

    This paper reports findings from a conversation analytic study of experimenter-participant interaction in parapsychology experiments. It shows how properties of communication through which the routine business of the experiment is conducted may have an impact on the research participant's subsequent performance. In this, the study explores social psychological features of the psychology laboratory. In particular, it examines aspects of Orne's (1962) account of what he called the demand characteristics of the psychological experiment. The data come from a corpus of audio recordings of experimenter-participant interaction during experiments on extra-sensory perception. These kinds of experiments, and the phenomena they purport to study, are undoubtedly controversial; however, the paper argues that there are grounds for social psychologists to consider parapsychology experiments as a class (albeit distinctive) of psychology experiments, and, therefore, as sites in which general social psychological and communicative phenomena can be studied. The empirical sections of the paper examine interaction during part of the experimental procedure when the experimenter verbally reviews a record of the participant's imagery reported during an earlier part of the experiment. The analysis shows that the way in which the experimenter acknowledges the research participants' utterances may be significant for the trajectory of the experiment and explores how the participants' subsequent performance in the experiment may be influenced by interactionally generated contingencies.

  12. Chromatic patchy particles: Effects of specific interactions on liquid structure

    NASA Astrophysics Data System (ADS)

    Vasilyev, Oleg A.; Klumov, Boris A.; Tkachenko, Alexei V.

    2015-07-01

    We study the structural and thermodynamic properties of patchy particle liquids, with a special focus on the role of "color," i.e., specific interactions between individual patches. A possible experimental realization of such "chromatic" interactions is by decorating the particle patches with single-stranded DNA linkers. The complementarity of the linkers can promote selective bond formation between predetermined pairs of patches. By using MD simulations, we compare the local connectivity, the bond orientation order, and other structural properties of the aggregates formed by the "colored" and "colorless" systems. The analysis is done for spherical particles with two different patch arrangements (tetrahedral and cubic). It is found that the aggregated (liquid) phase of the "colorless" patchy particles is better connected, denser and typically has stronger local order than the corresponding "colored" one. This, in turn, makes the colored liquid less stable thermodynamically. Specifically, we predict that in a typical case the chromatic interactions should increase the relative stability of the crystalline phase with respect to the disordered liquid, thus expanding its region in the phase diagram.

  13. Chromatic patchy particles: Effects of specific interactions on liquid structure

    SciTech Connect

    Vasilyev, Oleg A.; Tkachenko, Alexei V.; Klumov, Boris A.

    2015-07-13

    We study the structural and thermodynamic properties of patchy particle liquids, with a special focus on the role of “color,” i.e., specific interactions between individual patches. A possible experimental realization of such “chromatic” interactions is by decorating the particle patches with single-stranded DNA linkers. The complementarity of the linkers can promote selective bond formation between predetermined pairs of patches. By using MD simulations, we compare the local connectivity, the bond orientation order, and other structural properties of the aggregates formed by the “colored” and “colorless” systems. The analysis is done for spherical particles with two different patch arrangements (tetrahedral and cubic). It is found that the aggregated (liquid) phase of the “colorless” patchy particles is better connected, denser and typically has stronger local order than the corresponding “colored” one. This, in turn, makes the colored liquid less stable thermodynamically. Specifically, we predict that in a typical case the chromatic interactions should increase the relative stability of the crystalline phase with respect to the disordered liquid, thus expanding its region in the phase diagram.

  14. Chromatic patchy particles: Effects of specific interactions on liquid structure

    DOE PAGES

    Vasilyev, Oleg A.; Tkachenko, Alexei V.; Klumov, Boris A.

    2015-07-13

    We study the structural and thermodynamic properties of patchy particle liquids, with a special focus on the role of “color,” i.e., specific interactions between individual patches. A possible experimental realization of such “chromatic” interactions is by decorating the particle patches with single-stranded DNA linkers. The complementarity of the linkers can promote selective bond formation between predetermined pairs of patches. By using MD simulations, we compare the local connectivity, the bond orientation order, and other structural properties of the aggregates formed by the “colored” and “colorless” systems. The analysis is done for spherical particles with two different patch arrangements (tetrahedral andmore » cubic). It is found that the aggregated (liquid) phase of the “colorless” patchy particles is better connected, denser and typically has stronger local order than the corresponding “colored” one. This, in turn, makes the colored liquid less stable thermodynamically. Specifically, we predict that in a typical case the chromatic interactions should increase the relative stability of the crystalline phase with respect to the disordered liquid, thus expanding its region in the phase diagram.« less

  15. The Dynamic Reactance Interaction – How Vested Interests Affect People’s Experience, Behavior, and Cognition in Social Interactions

    PubMed Central

    Steindl, Christina; Jonas, Eva

    2015-01-01

    In social interactions, individuals may sometimes pursue their own interests at the expense of their interaction partner. Such self-interested behaviors impose a threat to the interaction partner’s freedom to act. The current article investigates this threat in the context of interdependence and reactance theory. We explore how vested interests influence reactance process stages of an advisor–client interaction. We aim to explore the interactional process that evolves. In two studies, participants took the perspective of a doctor (advisor) or a patient (client). In both studies we incorporated a vested interest. In Study 1 (N = 82) we found that in response to a vested interest of their interaction partner, patients indicated a stronger experience of reactance, more aggressive behavioral intentions, and more biased cognitions than doctors. A serial multiple mediation revealed that a vested interest engendered mistrust toward the interaction partner and this mistrust led to an emerging reactance process. Study 2 (N = 207) further demonstrated that doctors expressed their reactance in a subtle way: they revealed a classic confirmation bias when searching for additional information on their preliminary decision preference, indicating stronger defense motivation. We discuss how these findings can help us to understand how social interactions develop dynamically. PMID:26640444

  16. Flow interaction experiment. Volume 1: Aerothermal modeling, phase 2

    NASA Technical Reports Server (NTRS)

    Nikjooy, M.; Mongia, H. C.; Sullivan, J. P.; Murthy, S. N. B.

    1993-01-01

    An experimental and computational study is reported for the flow of a turbulent jet discharging into a rectangular enclosure. The experimental configurations consisting of primary jets only, annular jets only, and a combination of annular and primary jets are investigated to provide a better understanding of the flow field in an annular combustor. A laser Doppler velocimeter is used to measure mean velocity and Reynolds stress components. Major features of the flow field include recirculation, primary and annular jet interaction, and high turbulence. A significant result from this study is the effect the primary jets have on the flow field. The primary jets are seen to create statistically larger recirculation zones and higher turbulence levels. In addition, a technique called marker nephelometry is used to provide mean concentration values in the model combustor. Computations are performed using three levels of turbulence closures, namely k-epsilon model, algebraic second moment (ASM), and differential second moment (DSM) closure. Two different numerical schemes are applied. One is the lower-order power-law differencing scheme (PLDS) and the other is the higher-order flux-spline differencing scheme (FSDS). A comparison is made of the performance of these schemes. The numerical results are compared with experimental data. For the cases considered in this study, the FSDS is more accurate than the PLDS. For a prescribed accuracy, the flux-spline scheme requires a far fewer number of grid points. Thus, it has the potential for providing a numerical error-free solution, especially for three-dimensional flows, without requiring an excessively fine grid. Although qualitatively good comparison with data was obtained, the deficiencies regarding the modeled dissipation rate (epsilon) equation, pressure-strain correlation model, and the inlet epsilon profile and other critical closure issues need to be resolved before one can achieve the degree of accuracy required to

  17. Flow interaction experiment. Volume 2: Aerothermal modeling, phase 2

    NASA Technical Reports Server (NTRS)

    Nikjooy, M.; Mongia, H. C.; Sullivan, J. P.; Murthy, S. N. B.

    1993-01-01

    An experimental and computational study is reported for the flow of a turbulent jet discharging into a rectangular enclosure. The experimental configurations consisting of primary jets only, annular jets only, and a combination of annular and primary jets are investigated to provide a better understanding of the flow field in an annular combustor. A laser Doppler velocimeter is used to measure mean velocity and Reynolds stress components. Major features of the flow field include recirculation, primary and annular jet interaction, and high turbulence. A significant result from this study is the effect the primary jets have on the flow field. The primary jets are seen to create statistically larger recirculation zones and higher turbulence levels. In addition, a technique called marker nephelometry is used to provide mean concentration values in the model combustor. Computations are performed using three levels of turbulence closures, namely k-epsilon model, algebraic second moment (ASM), and differential second moment (DSM) closure. Two different numerical schemes are applied. One is the lower-order power-law differencing scheme (PLDS) and the other is the higher-order flux-spline differencing scheme (FSDS). A comparison is made of the performance of these schemes. The numerical results are compared with experimental data. For the cases considered in this study, the FSDS is more accurate than the PLDS. For a prescribed accuracy, the flux-spline scheme requires a far fewer number of grid points. Thus, it has the potential for providing a numerical error-free solution, especially for three-dimensional flows, without requiring an excessively fine grid. Although qualitatively good comparison with data was obtained, the deficiencies regarding the modeled dissipation rate (epsilon) equation, pressure-strain correlation model, and the inlet epsilon profile and other critical closure issues need to be resolved before one can achieve the degree of accuracy required to

  18. Habitat structure, trophic structure and ecosystem function: interactive effects in a bromeliad-insect community.

    PubMed

    Srivastava, Diane S

    2006-09-01

    Although previous studies have shown that ecosystem functions are affected by either trophic structure or habitat structure, there has been little consideration of their combined effects. Such interactions may be particularly important in systems where habitat and trophic structure covary. I use the aquatic insects in bromeliads to examine the combined effects of trophic structure and habitat structure on a key ecosystem function: detrital processing. In Costa Rican bromeliads, trophic structure naturally covaries with both habitat complexity and habitat size, precluding any observational analysis of interactions between factors. I therefore designed mesocosms that allowed each factor to be manipulated separately. Increases in mesocosm complexity reduced predator (damselfly larva) efficiency, resulting in high detritivore abundances, indirectly increasing detrital processing rates. However, increased complexity also directly reduced the per capita foraging efficiency of the detritivores. Over short time periods, these trends effectively cancelled each other out in terms of detrital processing. Over longer time periods, more complex patterns emerged. Increases in mesocosm size also reduced both predator efficiency and detritivore efficiency, leading to no net effect on detrital processing. In many systems, ecosystem functions may be impacted by strong interactions between trophic structure and habitat structure, cautioning against examining either effect in isolation.

  19. Stability and Interaction of Coherent Structure in Supersonic Reactive Wakes

    NASA Technical Reports Server (NTRS)

    Menon, Suresh

    1983-01-01

    A theoretical formulation and analysis is presented for a study of the stability and interaction of coherent structure in reacting free shear layers. The physical problem under investigation is a premixed hydrogen-oxygen reacting shear layer in the wake of a thin flat plate. The coherent structure is modeled as a periodic disturbance and its stability is determined by the application of linearized hydrodynamic stability theory which results in a generalized eigenvalue problem for reactive flows. Detailed stability analysis of the reactive wake for neutral, symmetrical and antisymmetrical disturbance is presented. Reactive stability criteria is shown to be quite different from classical non-reactive stability. The interaction between the mean flow, coherent structure and fine-scale turbulence is theoretically formulated using the von-Kaman integral technique. Both time-averaging and conditional phase averaging are necessary to separate the three types of motion. The resulting integro-differential equations can then be solved subject to initial conditions with appropriate shape functions. In the laminar flow transition region of interest, the spatial interaction between the mean motion and coherent structure is calculated for both non-reactive and reactive conditions and compared with experimental data wherever available. The fine-scale turbulent motion determined by the application of integral analysis to the fluctuation equations. Since at present this turbulence model is still untested, turbulence is modeled in the interaction problem by a simple algebraic eddy viscosity model. The applicability of the integral turbulence model formulated here is studied parametrically by integrating these equations for the simple case of self-similar mean motion with assumed shape functions. The effect of the motion of the coherent structure is studied and very good agreement is obtained with previous experimental and theoretical works for non-reactive flow. For the reactive case

  20. Thermodynamic and Structural Properties of Methanol-Water Solutions Using Non-Additive Interaction Models

    PubMed Central

    Zhong, Yang; Warren, G. Lee; Patel, Sandeep

    2014-01-01

    We study bulk structural and thermodynamic properties of methanol-water solutions via molecular dynamics simulations using novel interaction potentials based on the charge equilibration (fluctuating charge) formalism to explicitly account for molecular polarization at the atomic level. The study uses the TIP4P-FQ potential for water-water interactions, and the CHARMM-based (Chemistry at HARvard Molecular Mechanics) fluctuating charge potential for methanol-methanol and methanol-water interactions. In terms of bulk solution properties, we discuss liquid densities, enthalpies of mixing, dielectric constants, self-diffusion constants, as well as structural properties related to local hydrogen bonding structure as manifested in radial distribution functions and cluster analysis. We further explore the electronic response of water and methanol in the differing local environments established by the interaction of each species predominantly with molecules of the other species. The current force field for the alcohol-water interaction performs reasonably well for most properties, with the greatest deviation from experiment observed for the excess mixing enthalpies, which are predicted to be too favorable. This is qualitatively consistent with the overestimation of the methanol-water gas-phase interaction energy for the lowest-energy conformer (methanol as proton donor). Hydration free energies for methanol in TIP4P-FQ water are predicted to be −5.6±0.2 kcal/mole, in respectable agreement with the experimental value of −5.1 kcal/mole. With respect to solution micro-structure, the present cluster analysis suggests that the micro-scale environment for concentrations where select thermodynamic quantities reach extremal values is described by a bi-percolating network structure. PMID:18074339

  1. Near minimum-time maneuvers of the advanced space structures technology research experiment (ASTREX) test article: Theory and experiments

    NASA Technical Reports Server (NTRS)

    Vadali, Srinivas R.; Carter, Michael T.

    1994-01-01

    The Phillips Laboratory at the Edwards Air Force Base has developed the Advanced Space Structures Technology Research Experiment (ASTREX) facility to serve as a testbed for demonstrating the applicability of proven theories to the challenges of spacecraft maneuvers and structural control. This report describes the work performed on the ASTREX test article by Texas A&M University under contract NAS119373 as a part of the Control-Structure Interaction (CSI) Guest Investigator Program. The focus of this work is on maneuvering the ASTREX test article with compressed air thrusters that can be throttled, while attenuating structural excitation. The theoretical foundation for designing the near minimum-time thrust commands is based on the generation of smooth, parameterized optimal open-loop control profiles, and the determination of control laws for final position regulation and tracking using Lyapunov stability theory. Details of the theory, mathematical modeling, model updating, and compensation for the presence of 'real world' effects are described and the experimental results are presented. The results show an excellent match between theory and experiments.

  2. Understanding metallic bonding: Structure, process and interaction by Rasch analysis

    NASA Astrophysics Data System (ADS)

    Cheng, Maurice M. W.; Oon, Pey-Tee

    2016-08-01

    This paper reports the results of a survey of 3006 Year 10-12 students on their understandings of metallic bonding. The instrument was developed based on Chi's ontological categories of scientific concepts and students' understanding of metallic bonding as reported in the literature. The instrument has two parts. Part one probed into students' understanding of metallic bonding as (a) a submicro structure of metals, (b) a process in which individual metal atoms lose their outermost shell electrons to form a 'sea of electrons' and octet metal cations or (c) an all-directional electrostatic force between delocalized electrons and metal cations, that is, an interaction. Part two assessed students' explanation of malleability of metals, for example (a) as a submicro structural rearrangement of metal atoms/cations or (b) based on all-directional electrostatic force. The instrument was validated by the Rasch Model. Psychometric assessment showed that the instrument possessed reasonably good properties of measurement. Results revealed that it was reliable and valid for measuring students' understanding of metallic bonding. Analysis revealed that the structure, process and interaction understandings were unidimensional and in an increasing order of difficulty. Implications for the teaching of metallic bonding, particular through the use of diagrams, critiques and model-based learning, are discussed.

  3. Structure and Dynamics of Interacting Nanoparticles in Semidilute Polymer Solutions

    DOE PAGES

    Pollng-Skutvik, Ryan; Mongcopa, Katrina Irene S.; Faraone, Antonio; ...

    2016-08-17

    We investigate the structure and dynamics of silica nanoparticles and polymer chains in semidilute solutions of high molecular weight polystyrene in 2-butanone to determine the effect of long-range interparticle interactions on the coupling between particle and polymer dynamics. Particles at concentrations of 1–10 wt % are well dispersed in the semidilute polymer solutions and exhibit long-range electrostatic repulsions between particles. Because the particles are comparably sized to the radius of gyration of the polymer, the particle dynamics is predicted to couple to that of the polymer. We verify that the polymer structure and dynamics are not significantly affected by themore » particles, indicating that the particle–polymer coupling does not change with increasing particle loading. We find that the coupling between the dynamics of comparably sized particles and polymer results in subdiffusive particle dynamics, as expected. Over the interparticle distance, however, the particle dynamics is hindered and not fully described by the relaxation of the surrounding polymer chains. Instead, the particle dynamics is inversely related to the structure factor, suggesting that physical particle–polymer coupling on short length scales and interparticle interactions on long length scales both present energetic barriers to particle motion that lead to subdiffusive dynamics and de Gennes narrowing, respectively.« less

  4. Structure and Dynamics of Interacting Nanoparticles in Semidilute Polymer Solutions

    SciTech Connect

    Pollng-Skutvik, Ryan; Mongcopa, Katrina Irene S.; Faraone, Antonio; Narayanan, Suresh; Conrad, Jacinta C.; Krishnamoorti, Ramanan

    2016-08-17

    We investigate the structure and dynamics of silica nanoparticles and polymer chains in semidilute solutions of high molecular weight polystyrene in 2-butanone to determine the effect of long-range interparticle interactions on the coupling between particle and polymer dynamics. Particles at concentrations of 1–10 wt % are well dispersed in the semidilute polymer solutions and exhibit long-range electrostatic repulsions between particles. Because the particles are comparably sized to the radius of gyration of the polymer, the particle dynamics is predicted to couple to that of the polymer. We verify that the polymer structure and dynamics are not significantly affected by the particles, indicating that the particle–polymer coupling does not change with increasing particle loading. We find that the coupling between the dynamics of comparably sized particles and polymer results in subdiffusive particle dynamics, as expected. Over the interparticle distance, however, the particle dynamics is hindered and not fully described by the relaxation of the surrounding polymer chains. Instead, the particle dynamics is inversely related to the structure factor, suggesting that physical particle–polymer coupling on short length scales and interparticle interactions on long length scales both present energetic barriers to particle motion that lead to subdiffusive dynamics and de Gennes narrowing, respectively.

  5. Structures of multidomain proteins adsorbed on hydrophobic interaction chromatography surfaces.

    PubMed

    Gospodarek, Adrian M; Sun, Weitong; O'Connell, John P; Fernandez, Erik J

    2014-12-05

    In hydrophobic interaction chromatography (HIC), interactions between buried hydrophobic residues and HIC surfaces can cause conformational changes that interfere with separations and cause yield losses. This paper extends our previous investigations of protein unfolding in HIC chromatography by identifying protein structures on HIC surfaces under denaturing conditions and relating them to solution behavior. The thermal unfolding of three model multidomain proteins on three HIC surfaces of differing hydrophobicities was investigated with hydrogen exchange mass spectrometry (HXMS). The data were analyzed to obtain unfolding rates and Gibbs free energies for unfolding of adsorbed proteins. The melting temperatures of the proteins were lowered, but by different amounts, on the different surfaces. In addition, the structures of the proteins on the chromatographic surfaces were similar to the partially unfolded structures produced in the absence of a surface by temperature as well as by chemical denaturants. Finally, it was found that patterns of residue exposure to solvent on different surfaces at different temperatures can be largely superimposed. These findings suggest that protein unfolding on various HIC surfaces might be quantitatively related to protein unfolding in solution and that details of surface unfolding behavior might be generalized.

  6. Evaluation for the design of experience in virtual environments: modeling breakdown of interaction and illusion.

    PubMed

    Marsh, T; Wright, P; Smith, S

    2001-04-01

    New and emerging media technologies have the potential to induce a variety of experiences in users. In this paper, it is argued that the inducement of experience presupposes that users are absorbed in the illusion created by these media. Looking to another successful visual medium, film, this paper borrows from the techniques used in "shaping experience" to hold spectators' attention in the illusion of film, and identifies what breaks the illusion/experience for spectators. This paper focuses on one medium, virtual reality (VR), and advocates a transparent or "invisible style" of interaction. We argue that transparency keeps users in the "flow" of their activities and consequently enhances experience in users. Breakdown in activities breaks the experience and subsequently provides opportunities to identify and analyze potential causes of usability problems. Adopting activity theory, we devise a model of interaction with VR--through consciousness and activity--and introduce the concept of breakdown in illusion. From this, a model of effective interaction with VR is devised and the occurrence of breakdown in interaction and illusion is identified along a continuum of engagement. Evaluation guidelines for the design of experience are proposed and applied to usability problems detected in an empirical study of a head-mounted display (HMD) VR system. This study shows that the guidelines are effective in the evaluation of VR. Finally, we look at the potential experiences that may be induced in users and propose a way to evaluate user experience in virtual environments (VEs) and other new and emerging media.

  7. Experiment study on RC frame retrofitted by the external structure

    NASA Astrophysics Data System (ADS)

    Liu, Chunyang; Shi, Junji; Hiroshi, Kuramoto; Taguchi, Takashi; Kamiya, Takashi

    2016-09-01

    A new retrofitting method is proposed herein for reinforced concrete (RC) structures through attachment of an external structure. The external structure consists of a fiber concrete encased steel frame, connection slab and transverse beams. The external structure is connected to the existing structure through a connection slab and transverse beams. Pseudostatic experiments were carried out on one unretrofitted specimen and three retrofitted frame specimens. The characteristics, including failure mode, crack pattern, hysteresis loops behavior, relationship of strain and displacement of the concrete slab, are demonstrated. The results show that the load carrying capacity is obviously increased, and the extension length of the slab and the number of columns within the external frame are important influence factors on the working performance of the existing structure. In addition, the displacement difference between the existing structure and the outer structure was caused mainly by three factors: shear deformation of the slab, extraction of transverse beams, and drift of the conjunction part between the slab and the existing frame. Furthermore, the total deformation determined by the first two factors accounted for approximately 80% of the damage, therefore these factors should be carefully considered in engineering practice to enhance the effects of this new retrofitting method.

  8. Turbulence structures associated with fire-atmosphere interactions

    NASA Astrophysics Data System (ADS)

    Clements, C. B.; Seto, D.; Heilman, W. E.

    2013-12-01

    Wildland fires radically modify the atmospheric boundary layer by emitting large sensible and latent heat fluxes. These fluxes drive fire-atmosphere interactions at multiple scales resulting in fire-induced circulations in and around the fire front. During the fire front passage, FFP, turbulence kinetic energy increases due to increased heating and wind shear that develops in response to both free convection and fire-induced winds. New field observations from multiple fire experiments have shown that turbulence spectral energy increases during the FFP as a result of small eddies being shed from the fire front and that that normalized velocity spectra using the friction velocity collapse into a narrow band in the inertial subrange, suggesting that Monin-Obukhov scaling is a valid scaling parameter that can be used for wildfire prediction systems. Additionally, during FFP the mean profiles of winds and sensible heat flux change compared to ambient conditions due to the fire-atmosphere interactions. These profiles are also different during different environmental conditions such as grass fires in open field and fires within a forest canopy. This presentation will discuss new turbulence observations from the FireFlux II field experiment conducted in 2013 which indicate that during FFP there are also an increases in horizontal mean winds, friction velocity, horizontal and vertical velocity variances and a decrease in anisotropy in turbulence kinetic energy and are similar to lower intensity fires.

  9. Building a Learning Experience: What Do Learners' Online Interaction Data Imply?

    ERIC Educational Resources Information Center

    Kokoç, Mehmet; Altun, Arif

    2016-01-01

    It is still under debate whether learners' interaction data within e-learning and/or open learning environments could be considered as reflections of their learning experiences to be effective or not. Therefore, it is meaningful to explore the nature of these interactions and to make meaningful conclusions. This study aims to explore what the…

  10. Innovative Interactive Visitor Experiences Focused on Climate Change

    NASA Astrophysics Data System (ADS)

    Lettvin, E. E.

    2011-12-01

    Pacific Science Center has adopted a multi-pronged approach to introduce visitors to the concepts of climate change and linkages to human behavior in an informal science education setting. We leverage key fixed exhibit assets derived from collaborations with NOAA: Science on a Sphere and an exhibit kiosk showcasing local CO2 measurements that are adjacent on our exhibit floor. NOAA PMEL Scientists deployed a sensor at the top of the Space Needle that measures variability in atmospheric CO2 over Seattle; the kiosk showcases these near-real-time, daily, weekly and monthly measurements as well as similar observations from a NOAA buoy near Aberdeen, Washington. Displays of these data enable visitors to see first-hand varying CO2 levels in urban and remote marine environments as well as seasonal cycling. It also reveals quantifiable increases in CO2 levels over a relatively short time (~5 years). Trained interpreters help visitors understand linkages between personal behavior and corresponding CO2 footprints. Interpreters discuss connections between local and regional CO2 measurements displayed on the kiosk, and global Sphere datasets including NOAA Carbon Tracker, changing arctic sea ice coverage and sea level rise projections. Portable Discovery Carts, consisting of props and interactive, hands-on activities provide a platform for facilitated interpretation on a series of topics. We have developed two climate focused carts: 'Sinks and Sources' that examines materials and activities that produce and absorb carbon, and 'Ocean Acidification' that shows how absorption of atmospheric CO2 is changing ocean composition and its habitability for marine life. These carts can be deployed anywhere on the exhibit floor but are primarily used adjacent to the Sphere and the kiosk, making it possible to have a range of conversations about global and local CO2 levels, linkages to individual and collective behaviour and associated implications. Additional collaborations with members of

  11. Passively Adaptive Inflatable Structure for the Shooting Star Experiment

    NASA Technical Reports Server (NTRS)

    Tinker, Michael L..

    1998-01-01

    An inflatable structural system is described for the Shooting Star Experiment that is a technology demonstrator flight for solar thermal propulsion. The inflatable structure is a pressurized assembly used in orbit to support a fresnel lens for focusing sunlight into a thermal storage engine. When the engine temperature reaches a preset level, the propellant is injected into the storage engine, absorbs heat from a heat exchanger, and is expanded through the nozzle to produce thrust. The inflatable structure is an adaptive system in that a regulator and relief valve are utilized to maintain pressure within design limits during the full range of orbital conditions. Further, the polyimide film material used for construction of the inflatable is highly nonlinear, with modulus varying as a function of frequency, temperature, and level of excitation. A series of tests is described for characterizing the structure in response to various operating conditions.

  12. Electromechanical co-design and experiment of structurally integrated antenna

    NASA Astrophysics Data System (ADS)

    Zhou, Jinzhu; Huang, Jin; Song, Liwei; Zhang, Dan; Ma, Yunchao

    2015-03-01

    This paper proposes an electromechanical co-design method of a structurally integrated antenna to simultaneously meet mechanical and electrical requirements. The method consists of three stages. The first stage involves finishing an initial design of the microstrip antenna without a facesheet or honeycomb, according to some predefined performances. Subsequently, the facesheet and honeycomb of the structurally integrated antenna are designed using an electromechanical co-design optimization. Based on the results from the first and second stages, a fine full-wave electromagnetic model is developed and the coarse design results are further optimized to meet the electrical performance. The co-design method is applied to the design of a 2.5 GHz structurally integrated antenna, and then the designed antenna is fabricated. Experiments from the mechanical and electrical performances are conducted, and the results confirm the effectiveness of the co-design method. This method shows great promise for the multidisciplinary design of a structurally integrated antenna.

  13. Search for Contact Interactions in Dilepton Final State in the CMS Experiment: Generator-Level Studies

    NASA Astrophysics Data System (ADS)

    Zaleski, Shawn

    2017-01-01

    A set of contact interaction (CI) Monte Carlo events, for which Standard Model Drell-Yan events are background, are generated using a leading-order parton-shower generator, Pythia8. We consider three isoscalar models with three different helicity structures, left-left (LL), left-right/right-left (LR), and right­right (RR), each with destructive and constructive interference. For each of these models, 150,000 events are generated for analysis of CI interactions in the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) with a centre of mass energy of 13 TeV. This study is a generator level study, and detector effects are accounted for by application of kinematic cuts on the generator-level quantities rather than application of a detailed detector simulation package (e.g. GEANT). Distributions of dilepton invariant mass, Collins-Soper angle, and the forward-backward asymmetry are compared with those arising from pure Drell-Yan events.

  14. Structural basis of Keap1 interactions with Nrf2

    PubMed Central

    Canning, Peter; Sorrell, Fiona J.; Bullock, Alex N.

    2015-01-01

    Keap1 is a highly redox-sensitive member of the BTB-Kelch family that assembles with the Cul3 protein to form a Cullin–RING E3 ligase complex for the degradation of Nrf2. Oxidative stress disables Keap1, allowing Nrf2 protein levels to accumulate for the transactivation of critical stress response genes. Consequently, the Keap1–Nrf2 system is extensively pursued for the development of protein–protein interaction inhibitors that will stabilize Nrf2 for therapeutic effect in conditions of neurodegeneration, inflammation, and cancer. Here we review current progress toward the structure determination of Keap1 and its protein complexes with Cul3, Nrf2 substrate, and small-molecule antagonists. Together the available structures establish a rational three-dimensional model to explain the two-site binding of Nrf2 as well as its efficient ubiquitination. PMID:26057936

  15. Discrete Data Transfer Technique for Fluid-Structure Interaction

    NASA Technical Reports Server (NTRS)

    Samareh, Jamshid A.

    2007-01-01

    This paper presents a general three-dimensional algorithm for data transfer between dissimilar meshes. The algorithm is suitable for applications of fluid-structure interaction and other high-fidelity multidisciplinary analysis and optimization. Because the algorithm is independent of the mesh topology, we can treat structured and unstructured meshes in the same manner. The algorithm is fast and accurate for transfer of scalar or vector fields between dissimilar surface meshes. The algorithm is also applicable for the integration of a scalar field (e.g., coefficients of pressure) on one mesh and injection of the resulting vectors (e.g., force vectors) onto another mesh. The author has implemented the algorithm in a C++ computer code. This paper contains a complete formulation of the algorithm with a few selected results.

  16. Development of a Fluid Structures Interaction Test Technique for Fabrics

    NASA Technical Reports Server (NTRS)

    Zilliac, Gregory G.; Heineck, James T.; Schairer, Edward T.; Mosher, Robert N.; Garbeff, Theodore Joseph

    2012-01-01

    Application of fluid structures interaction (FSI) computational techniques to configurations of interest to the entry, descent and landing (EDL) community is limited by two factors - limited characterization of the material properties for fabrics of interest and insufficient experimental data to validate the FSI codes. Recently ILC Dover Inc. performed standard tests to characterize the static stress-strain response of four candidate fabrics for use in EDL applications. The objective of the tests described here is to address the need for a FSI dataset for CFD validation purposes. To reach this objective, the structural response of fabrics was measured in a very simple aerodynamic environment with well controlled boundary conditions. Two test series were undertaken. The first series covered a range of tunnel conditions and the second focused on conditions that resulted in fabric panel buckling.

  17. Structural basis of Keap1 interactions with Nrf2.

    PubMed

    Canning, Peter; Sorrell, Fiona J; Bullock, Alex N

    2015-11-01

    Keap1 is a highly redox-sensitive member of the BTB-Kelch family that assembles with the Cul3 protein to form a Cullin-RING E3 ligase complex for the degradation of Nrf2. Oxidative stress disables Keap1, allowing Nrf2 protein levels to accumulate for the transactivation of critical stress response genes. Consequently, the Keap1-Nrf2 system is extensively pursued for the development of protein-protein interaction inhibitors that will stabilize Nrf2 for therapeutic effect in conditions of neurodegeneration, inflammation, and cancer. Here we review current progress toward the structure determination of Keap1 and its protein complexes with Cul3, Nrf2 substrate, and small-molecule antagonists. Together the available structures establish a rational three-dimensional model to explain the two-site binding of Nrf2 as well as its efficient ubiquitination.

  18. The NIF Shear Experiment: Emergent Coherent Structures and Initial Conditions

    NASA Astrophysics Data System (ADS)

    Flippo, K. A.; Doss, F. W.; Merritt, E. C.; di Stefano, C. A.; Devolder, B. G.; Kurien, S.; Kot, L.; Loomis, E. N.; Murphy, T. J.; Perry, T. S.; Kline, J. L.; Huntington, C. M.; Nagel, S. R.; MacLaren, S. A.; Schmidt, D. W.

    2016-10-01

    The NIF Shear experiments are designed to stress turbulence models at high Atwood numbers, high convective Mach number, and in a highly compressible regime. The NIF laser system is used to drive two hohlraums on either end of the experiment, which convert the laser drive into a bath of soft x-rays, 250eV in temperature. The counter-propagating shocks and flow, pressure balance the shear layer, such that it can grow due to the KH instability in the center of the experiment for 20 ns. These experiments are the first High Energy Density (HED) hydro-instability studies to show emergent coherent Kelvin-Helmholtz (KH) structures arising from random broadband seeds, and the first to control the phenomenological evolution of the tracer layer by controlling the initial surface roughness conditions. The change in initial conditions forces the system evolution on a different path that does not appear to reach a universal nor self-similar state by the end of the experiment. The experiment was modeled using the multi-physics hydrodynamic code RAGE with the BHR turbulence model. The initial scale-length of the model is modified to match the data. When the model is turned off, the pure hydrodynamics do not capture the behavior of the mixing layer and cannot match the data.

  19. Thermodynamic and structural properties of methanol-water solutions using nonadditive interaction models.

    PubMed

    Zhong, Yang; Warren, G Lee; Patel, Sandeep

    2008-05-01

    We study bulk structural and thermodynamic properties of methanol-water solutions via molecular dynamics simulations using novel interaction potentials based on the charge equilibration (fluctuating charge) formalism to explicitly account for molecular polarization at the atomic level. The study uses the TIP4P-FQ potential for water-water interactions, and the CHARMM-based (Chemistry at HARvard Molecular Mechanics) fluctuating charge potential for methanol-methanol and methanol-water interactions. In terms of bulk solution properties, we discuss liquid densities, enthalpies of mixing, dielectric constants, self-diffusion constants, as well as structural properties related to local hydrogen bonding structure as manifested in radial distribution functions and cluster analysis. We further explore the electronic response of water and methanol in the differing local environments established by the interaction of each species predominantly with molecules of the other species. The current force field for the alcohol-water interaction performs reasonably well for most properties, with the greatest deviation from experiment observed for the excess mixing enthalpies, which are predicted to be too favorable. This is qualitatively consistent with the overestimation of the methanol-water gas-phase interaction energy for the lowest-energy conformer (methanol as proton donor). Hydration free energies for methanol in TIP4P-FQ water are predicted to be -5.6 +/- 0.2 kcal/mol, in respectable agreement with the experimental value of -5.1 kcal/mol. With respect to solution microstructure, the present cluster analysis suggests that the microscale environment for concentrations where select thermodynamic quantities reach extremal values is described by a bipercolating network structure.

  20. How Do Parents of Children with Communication Difficulties Experience Video Interaction Guidance? A Practitioner Research Project

    ERIC Educational Resources Information Center

    Taylor, Amelia Fay

    2016-01-01

    This practitioner research article sought to provide an interpretation of the parental experience of video interaction guidance (VIG). Two mothers and one grandmother participated in one cycle of VIG and one interview about their experiences. Transcripts were analysed using Interpretive Phenomenological Analysis (IPA). Findings indicated that…

  1. Lysozyme Thermal Denaturation and Self-Interaction: Four Integrated Thermodynamic Experiments for the Physical Chemistry Laboratory

    ERIC Educational Resources Information Center

    Schwinefus, Jeffrey J.; Schaefle, Nathaniel J.; Muth, Gregory W.; Miessler, Gary L.; Clark, Christopher A.

    2008-01-01

    As part of an effort to infuse our physical chemistry laboratory with biologically relevant, investigative experiments, we detail four integrated thermodynamic experiments that characterize the denaturation (or unfolding) and self-interaction of hen egg white lysozyme as a function of pH and ionic strength. Students first use Protein Explorer to…

  2. Study of turbulence and interacting inertial modes in a differentially rotating spherical shell experiment

    NASA Astrophysics Data System (ADS)

    Hoff, Michael; Harlander, Uwe; Triana, Santiago Andrés

    2016-08-01

    We present a study of inertial modes in a differentially rotating spherical shell (spherical Couette flow) experiment with a radius ratio of η =1 /3 . Inertial modes are Coriolis-restored linear wave modes which often arise in rapidly rotating fluids. Recent experimental work has shown that inertial modes exist in a spherical Couette flow for Ωi<Ωo , where Ωi and Ωo are the inner and outer sphere rotation rate. A finite number of particular inertial modes has previously been found. By scanning the Rossby number from -2.5 experiments. We show that the kinetic energy of the dominant inertial mode dramatically increases with decreasing Rossby number, which eventually leads to a wave breaking and an increase of small-scale structures at a critical Rossby number. Such a transition in a spherical Couette flow has not been described before. The critical Rossby number scales with the Ekman number as E1 /5. Additionally, the increase of small-scale features beyond the transition transfers energy to a massively enhanced mean flow around the tangent cylinder. In this context, we discuss an interaction between the dominant inertial modes with a geostrophic Rossby mode exciting secondary modes whose frequencies match the triadic resonance condition.

  3. IRIS Controlled Source Seismic Experiments: Continental Structure, Instrumentation, and Education

    NASA Astrophysics Data System (ADS)

    Mooney, W. D.; Keller, G. R.

    2004-12-01

    The controlled-source seismology program of IRIS/PASSCAL has made major contributions to the study of continental structure and evolution. It has also undergone major developments in seismic instrumentation. The first PASSCAL experiments (1984/85) targeted the Basin and Range Province and the Ouachita orogenic belt. The Basin and Range study provided remarkably clear images of this thin, highly-extended crust, while the Ouachita experiment tested competing hypotheses for the deep structure of this Paleozoic orogen. However, both of these projects were limited by a lack of seismic instruments. The situation improved in the late 1980's with the benefit of a mixed array of 600 seismic recorders from the USGS, Stanford, and the Geological Survey of Canada. The resolution achieved with these instruments was revolutionary. Results include the imaging of such remarkable features as crustal-scale duplexes in the Brooks Range compressional orogen of northern Alaska, and of crustal "core complexes" in the extended crust of southwest Arizona. The 3-channel PASSCAL Jr. instrument was developed, leading to experiments in which ˜1000 instruments were deployed, including three-component recording. This complex mix of instruments served the community well for several years, but required large, complex instrument centers and lots of technical support. With input from PASSCAL and the international community, a newly designed, compact instrument (the Texan) was finalized in the spring of 1998, and the first 200 instruments was delivered to the Univ. of Texas-El Paso in late 1998. The present instrument pool of Texans exceeds 1,400 and these have been used on such projects as the high-resolution imaging of the Los Angeles and San Fernando basins (LARSE I and II experiments), where active thrust faults have been imaged. Controlled-source seismic experiments are now very numerous. During calendar year 2004 alone, portable Texan instruments have traveled from Venezuela to Denmark

  4. Analytic and Simulation Studies of Dust Grain Interaction and Structuring

    NASA Astrophysics Data System (ADS)

    Lampe, Martin; Joyce, Glenn; Ganguli, Gurudas

    For dust grains in stationary plasma, a quantitative assessment is made of the effect of centrifugal potential barriers on ion trajectories near a grain. It is shown that in most situations of interest the barriers are weak and only marginally affect the validity of the orbital-motion-limited (OML) theory. The OML theory is then used to show that the electrostatic interaction between grains is always repulsive. The ion-shadowing force is calculated, and it is shown that this force can lead to a weak net attraction between grains at long range, under certain conditions with large grains, dense plasma, and/or low gas pressure. For grains in streaming plasma at or near the sheath, it is shown that nonlinear effects are weak and the grains can be represented as dressed particles interacting via the dynamically shielded Coulomb interaction, which includes wakefields, Landau damping, and collisional damping. The Dynamically Shielded Dust (DSD) simulation code, which is based on this model, is described and a simulation is shown for strongly coupled grains in flowing plasma. The simulation shows ordering of the grains into rigid strings aligned with the ion flow, and looser glass-like organization of the strings in the transverse plane. The presence of strings with odd and even numbers of grains results in stratification of the grains into planes with an alternating structure.

  5. Structured residual technique for malfunction isolation in interacting systems

    SciTech Connect

    Hardy, C.R.; Miller, D.W.; Hajek, B.K. )

    1992-01-01

    Researchers in the field of fault detection and isolation have presented schemes for diagnosing faults in systems in the presence of unknown input disturbances. These techniques, known collectively as input disturbance decoupling, can be used to isolate a particular system from other systems in a complex process plant. The ability to isolate the operation of a system from systems with which it interacts is desirable when diagnosing faults in complex plants. The diagnosis problem can then be broken down into a set of relatively simple diagnostic tasks and the results evaluated using a knowledge-based approach. One such approach, known as hierarchical classification, has been used for malfunction diagnosis in both nuclear power and chemical plants. Systems that strongly interact are common in nuclear power plants. For example, in the simplified boiling water reactor (BWR) pressure control system (PCS) model of Fig. 1, steam flow from the main steam lines collects in the steam header. The header acts as a source of steam to several plant systems besides the high-pressure turbine. Thus, a change in any one of these auxiliary systems will affect the operation of the PCS. These unmeasured influences complicate the problem of isolating the PCS from the remainder of the plant. The authors have used structured residuals as a disturbance decoupling technique to isolate interacting systems in a BWR model. In this paper, we provide a brief summary of the method and show an example of its application.

  6. Structural Interactions within Lithium Salt Solvates: Cyclic Carbonates and Esters

    SciTech Connect

    Seo, D. M.; Afroz, Taliman; Allen, Joshua L.; Boyle, Paul D.; Trulove, Paul C.; De Long, Hugh C.; Henderson, Wesley A.

    2014-11-13

    Only limited information is available regarding the manner in which cyclic carbonate and ester solvents coordinate Li+ cations in electrolyte solutions for lithium batteries. One approach to gleaning significant insight into these interactions is to examine crystalline solvate structures. To this end, eight new solvate structures are reported with ethylene carbonate, γ-butyrolactone and γ-valerolactone: (EC)3:LiClO4, (EC)2:LiClO4, (EC)2:LiBF4, (GBL)4:LiPF6, (GBL)1:LiClO4, (GVL)1:LiClO4, (GBL)1:LiBF4 and (GBL)1:LiCF3SO3. The crystal structure of (EC)1:LiCF3SO3 is also re-reported for comparison. These structures enable the factors which govern the manner in which the ions are coordinated and the ion/solvent packing—in the solid-state—to be scrutinized in detail.

  7. Structural Interactions within Lithium Salt Solvates. Acyclic Carbonates and Esters

    SciTech Connect

    Afroz, Taliman; Seo, D. M.; Han, Sang D.; Boyle, Paul D.; Henderson, Wesley A.

    2015-03-06

    Solvate crystal structures serve as useful models for the molecular-level interactions within the diverse solvates present in liquid electrolytes. Although acyclic carbonate solvents are widely used for Li-ion battery electrolytes, only three solvate crystal structures with lithium salts are known for these and related solvents. The present work, therefore, reports six lithium salt solvate structures with dimethyl and diethyl carbonate: (DMC)2:LiPF6, (DMC)1:LiCF3SO3, (DMC)1/4:LiBF4, (DEC)2:LiClO4, (DEC)1:LiClO4 and (DEC)1:LiCF3SO3 and four with the structurally related methyl and ethyl acetate: (MA)2:LiClO4, (MA)1:LiBF4, (EA)1:LiClO4 and (EA)1:LiBF4.

  8. Magnetic monopole interactions: shell structure of meson and baryon states

    SciTech Connect

    Akers, D.

    1986-12-01

    It is suggested that a low-mass magnetic monopole of Dirac charge g = (137/2)e may be interacting with a c-quark's magnetic dipole moment to produce Zeeman splitting of meson states. The mass M/sub 0/ = 2397 MeV of the monopole is in contrast to the 10/sup 16/-GeV monopoles of grand unification theories (GUT). It is shown that shell structure of energy E/sub n/ = M/sub 0/ + 1/4nM/sub 0/... exists for meson states. The presence of symmetric meson states leads to the identification of the shell structure. The possible existence of the 2397-MeV magnetic monopole is shown to quantize quark masses in agreement with calculations of quantum chromodynamics (QCD). From the shell structure of meson states, the existence of two new mesons is predicted: eta(1814 +/- 50 MeV) with I/sup G/(J/sup PC/) = 0/sup +/(0/sup - +/) and eta/sub c/ (3907 +/- 100 MeV) with J/sup PC/ = 0/sup - +/. The presence of shell structure for baryon states is shown.

  9. Dynamic protein interaction networks and new structural paradigms in signaling

    PubMed Central

    Csizmok, Veronika; Follis, Ariele Viacava; Kriwacki, Richard W.; Forman-Kay, Julie D.

    2017-01-01

    Understanding signaling and other complex biological processes requires elucidating the critical roles of intrinsically disordered proteins and regions (IDPs/IDRs), which represent ~30% of the proteome and enable unique regulatory mechanisms. In this review we describe the structural heterogeneity of disordered proteins that underpins these mechanisms and the latest progress in obtaining structural descriptions of ensembles of disordered proteins that are needed for linking structure and dynamics to function. We describe the diverse interactions of IDPs that can have unusual characteristics such as “ultrasensitivity” and “regulated folding and unfolding”. We also summarize the mounting data showing that large-scale assembly and protein phase separation occurs within a variety of signaling complexes and cellular structures. In addition, we discuss efforts to therapeutically target disordered proteins with small molecules. Overall, we interpret the remodeling of disordered state ensembles due to binding and post-translational modifications within an expanded framework for allostery that provides significant insights into how disordered proteins transmit biological information. PMID:26922996

  10. Spin Structure Functions of the Proton - SANE experiment

    NASA Astrophysics Data System (ADS)

    Baghdasaryan, Hovhannes

    2012-03-01

    The Spin Asymmetries of the Nucleon Experiment (SANE) is a measurement of inclusive electron scattering parallel and near perpendicular double spin asymmetries from a proton target. The main goal of the experiment was to measure A and A80 and to extract the spin asymmetries of the proton A1^p, A2^p and the spin structure functions g1^p and g2^p. Using the Thomas Jefferson National Accelerator Facility's polarized electron beam and the University of Virginia's polarized frozen ammonia (^14NH3) target in Hall C, the experiment ran in 2009, collecting data in a Q^2 region from 2.5 to 6.5 GeV^2 and between Bjorken x of 0.3 and 0.8. Particle detection was accomplished using the Big Electron Telescope Array (BETA), a novel non-magnetic detector. The physics motivation for the experiment and a brief overview of the polarized target and the detector will be presented along with the analysis developed in order to extract the proton spin asymmetries and structure functions. Results will be presented.

  11. Structural organization and interactions of transmembrane domains in tetraspanin proteins

    PubMed Central

    Kovalenko, Oleg V; Metcalf, Douglas G; DeGrado, William F; Hemler, Martin E

    2005-01-01

    Background Proteins of the tetraspanin family contain four transmembrane domains (TM1-4) linked by two extracellular loops and a short intracellular loop, and have short intracellular N- and C-termini. While structure and function analysis of the larger extracellular loop has been performed, the organization and role of transmembrane domains have not been systematically assessed. Results Among 28 human tetraspanin proteins, the TM1-3 sequences display a distinct heptad repeat motif (abcdefg)n. In TM1, position a is occupied by structurally conserved bulky residues and position d contains highly conserved Asn and Gly residues. In TM2, position a is occupied by conserved small residues (Gly/Ala/Thr), and position d has a conserved Gly and two bulky aliphatic residues. In TM3, three a positions of the heptad repeat are filled by two leucines and a glutamate/glutamine residue, and two d positions are occupied by either Phe/Tyr or Val/Ile/Leu residues. No heptad motif is apparent in TM4 sequences. Mutations of conserved glycines in human CD9 (Gly25 and Gly32 in TM1; Gly67 and Gly74 in TM2) caused aggregation of mutant proteins inside the cell. Modeling of the TM1-TM2 interface in CD9, using a novel algorithm, predicts tight packing of conserved bulky residues against conserved Gly residues along the two helices. The homodimeric interface of CD9 was mapped, by disulfide cross-linking of single-cysteine mutants, to the vicinity of residues Leu14 and Phe17 in TM1 (positions g and c) and Gly77, Gly80 and Ala81 in TM2 (positions d, g and a, respectively). Mutations of a and d residues in both TM1 and TM2 (Gly25, Gly32, Gly67 and Gly74), involved in intramolecular TM1-TM2 interaction, also strongly diminished intermolecular interaction, as assessed by cross-linking of Cys80. Conclusion Our results suggest that tetraspanin intra- and intermolecular interactions are mediated by conserved residues in adjacent, but distinct regions of TM1 and TM2. A key structural element that

  12. Simulating Pediatric Ventricular Assist Device Operation Using Fluid Structure Interaction

    NASA Astrophysics Data System (ADS)

    Long, Chris; Bazilevs, Yuri; Marsden, Alison

    2012-11-01

    Ventricular Assist Devices (VADs) provide mechanical circulatory support to patients in heart failure. They are primarily used to extend life until cardiac transplant, but also show promise as a ``bridge-to-recovery'' device in pediatric patients. Commercially available pediatric pumps are pulsatile displacement pumps, with two distinct chambers for air and blood separated by a thin, flexible membrane. The air chamber pneumatically drives the membrane, which drives blood through the other chamber via displacement. The primary risk factor associated with these devices is stroke or embolism due to thrombogenesis in the blood chamber, occurring in as many as 40% of patients. Our goal is to perform simulations that accurately model the hemodynamics of the device, as well as the non-linear membrane buckling. We apply a finite-element based fluid solver, with an Arbitrary Lagrangian-Eulerian (ALE) framework to account for mesh motion. Isogeometric Analysis with a Kirchhoff-Love shell formulation is used on the membrane, and two distinct fluid subdomains are used for the air and blood chambers. The Fluid Structure Interaction (FSI) problem is solved simultaneously, using a Matrix Free method to model the interactions at the fluid-structure boundary. Methods and results are presented.

  13. Fluid Structure Interaction Analysis on Sidewall Aneurysm Models

    NASA Astrophysics Data System (ADS)

    Hao, Qing

    2016-11-01

    Wall shear stress is considered as an important factor for cerebral aneurysm growth and rupture. The objective of present study is to evaluate wall shear stress in aneurysm sac and neck by a fluid-structure-interaction (FSI) model, which was developed and validated against the particle image velocimetry (PIV) data. In this FSI model, the flow characteristics in a straight tube with different asymmetric aneurysm sizes over a range of Reynolds numbers from 200 to 1600 were investigated. The FSI results agreed well with PIV data. It was found that at steady flow conditions, when Reynolds number above 700, one large recirculating vortex would be formed, occupying the entire aneurysm sac. The center of the vortex is located at region near to the distal neck. A pair of counter rotating vortices would however be formed at Reynolds number below 700. Wall shear stresses reached highest level at the distal neck of the aneurysmal sac. The vortex strength, in general, is stronger at higher Reynolds number. Fluid Structure Interaction Analysis on Sidewall Aneurysm Models.

  14. Community structure of non-coding RNA interaction network.

    PubMed

    Nacher, Jose C

    2013-04-02

    Rapid technological advances have shown that the ratio of non-protein coding genes rises to 98.5% in humans, suggesting that current knowledge on genetic information processing might be largely incomplete. It implies that protein-coding sequences only represent a small fraction of cellular transcriptional information. Here, we examine the community structure of the network defined by functional interactions between non-coding RNAs (ncRNAs) and proteins related bio-macromolecules (PRMs) using a two-fold approach: modularity in bipartite network and k-clique community detection. First, the high modularity scores as well as the distribution of community sizes showing a scaling-law revealed manifestly non-random features. Second, the k-clique sub-graphs and overlaps show that the identified communities of the ncRNA molecules of H. sapiens can potentially be associated with certain functions. These findings highlight the complex modular structure of ncRNA interactions and its possible regulatory roles in the cell.

  15. A self-excited flapper from fluid-structure interaction

    NASA Astrophysics Data System (ADS)

    Curet, Oscar M.; Breuer, Kenneth S.

    2010-11-01

    The flexible nature of lifting and propulsive surfaces is a common characteristic of aquatic and aerial locomotion in animals. These surfaces may not only move actively, but also passively or with a combination of both. What is the nature of this passive movement? What is the role of this passive motion on force generation, efficiency and muscle control? Here, we present results using a simple wing model with two degrees of freedom designed to study passive flapping, and fluid-structure interaction. The wing is composed of a flat plate with a hinged trailing flap. The wing is cantilevered to the main body to enable a flapping motion with a well-defined natural frequency. We test the wing model in a wind tunnel. At low speed the wing is stationary. Above a critical velocity the trailing wing section starts to oscillate, generating an oscillating lift force on the wing. This oscillating lift force results on a self-excited flapping motion of the wing. We measure the kinematics and the forces generated by the wing as a function of flow velocity and stiffness of the cantilever. Comparisons with aeroelasticity theory will be presented as well as details of the fluid-structure interactions.

  16. Reduced order modeling of fluid/structure interaction.

    SciTech Connect

    Barone, Matthew Franklin; Kalashnikova, Irina; Segalman, Daniel Joseph; Brake, Matthew Robert

    2009-11-01

    This report describes work performed from October 2007 through September 2009 under the Sandia Laboratory Directed Research and Development project titled 'Reduced Order Modeling of Fluid/Structure Interaction.' This project addresses fundamental aspects of techniques for construction of predictive Reduced Order Models (ROMs). A ROM is defined as a model, derived from a sequence of high-fidelity simulations, that preserves the essential physics and predictive capability of the original simulations but at a much lower computational cost. Techniques are developed for construction of provably stable linear Galerkin projection ROMs for compressible fluid flow, including a method for enforcing boundary conditions that preserves numerical stability. A convergence proof and error estimates are given for this class of ROM, and the method is demonstrated on a series of model problems. A reduced order method, based on the method of quadratic components, for solving the von Karman nonlinear plate equations is developed and tested. This method is applied to the problem of nonlinear limit cycle oscillations encountered when the plate interacts with an adjacent supersonic flow. A stability-preserving method for coupling the linear fluid ROM with the structural dynamics model for the elastic plate is constructed and tested. Methods for constructing efficient ROMs for nonlinear fluid equations are developed and tested on a one-dimensional convection-diffusion-reaction equation. These methods are combined with a symmetrization approach to construct a ROM technique for application to the compressible Navier-Stokes equations.

  17. Modeling fluid-structure interactions in shallow microchannels

    NASA Astrophysics Data System (ADS)

    Shidhore, Tanmay C.; Christov, Ivan C.

    2016-11-01

    Rectangular microfluidic conduits with deformable walls are some of the simplest and most extensively studied microfluidic devices, primarily due to their practical design applications in a variety of fields like biology, medical diagnostics (e.g., lab-on-a-chip), nanotechnology, etc. Experimentally, these devices are found to deform into a non-rectangular cross-section due to fluid-structure interactions occurring at the channel walls. These deformations significantly affect the flow profile, which results in a non-linear relationship between the flow rate and the pressure drop, which cannot be explained by a 'generalised Poiseuille flow solution'. To this end, we perform a numerical study of these fluid-structure interactions and their effect on the flow rate and the pressure drop occurring in microfluidic conduits with a single deformable wall. The behavior of several shallow conduit systems (l >> w >> h) with rigid base and side walls and a soft top wall (e.g., PDMS) is simulated under laminar flow conditions using the commercial software suite ANSYS. Simulation results are compared against experimental pressure drop-flow rate data from the literature and also newly developed analytical expressions for the wall deformation, the pressure and the normalized flow rate.

  18. Structure of colloidal gels at intermediate concentrations: the role of competing interactions.

    PubMed

    Capellmann, Ronja F; Valadez-Pérez, Néstor E; Simon, Benedikt; Egelhaaf, Stefan U; Laurati, Marco; Castañeda-Priego, Ramón

    2016-11-23

    Colloidal gels formed by colloid-polymer mixtures with an intermediate volume fraction (ϕc ≈ 0.4) are investigated by confocal microscopy. In addition, we have performed Monte Carlo simulations based on a simple effective pair potential that includes a short-range attractive contribution representing depletion interactions, and a longer-range repulsive contribution describing the electrostatic interactions due to the presence of residual charges. Despite neglecting non-equilibrium effects, experiments and simulations yield similar gel structures, characterised by, e.g., the pair, angular and bond distribution functions. We find that the structure hardly depends on the strength of the attraction if the electrostatic contribution is fixed, but changes significantly if the electrostatic screening is changed. This delicate balance between attractions and repulsions, which we quantify by the second virial coefficient, also determines the location of the gelation boundary.

  19. Data-driven interactive 3D medical image segmentation based on structured patch model.

    PubMed

    Park, Sang Hyun; Yun, Il Dong; Lee, Sang Uk

    2013-01-01

    In this paper, we present a novel three dimensional interactive medical image segmentation method based on high level knowledge of training set. Since the interactive system should provide intermediate results to an user quickly, insufficient low level models are used for most of previous methods. To exploit the high level knowledge within a short time, we construct a structured patch model that consists of multiple corresponding patch sets. The structured patch model includes the spatial relationships between neighboring patch sets and the prior knowledge of the corresponding patch set on each local region. The spatial relationships accelerate the search of corresponding patch in test time, while the prior knowledge improves the segmentation accuracy. The proposed framework provides not only fast editing tool, but the incremental learning system through adding the segmentation result to the training set. Experiments demonstrate that the proposed method is useful for fast and accurate segmentation of target objects from the multiple medical images.

  20. Experiments for locating damaged truss members in a truss structure

    NASA Technical Reports Server (NTRS)

    Mcgowan, Paul E.; Smith, Suzanne W.; Javeed, Mehzad

    1991-01-01

    Locating damaged truss members in large space structures will involve a combination of sensing and diagnostic techniques. Methods developed for damage location require experimental verification prior to on-orbit applications. To this end, a series of experiments for locating damaged members using a generic, ten bay truss structure were conducted. A 'damaged' member is a member which has been removed entirely. Previously developed identification methods are used in conjunction with the experimental data to locate damage. Preliminary results to date are included, and indicate that mode selection and sensor location are important issues for location performance. A number of experimental data sets representing various damage configurations were compiled using the ten bay truss. The experimental data and the corresponding finite element analysis models are available to researchers for verification of various methods of structure identification and damage location.

  1. Structural Hamiltonian chaos in the coherent parametric atom-field interaction

    NASA Astrophysics Data System (ADS)

    Ioussoupov, V. I.; Kon'kov, L. E.; Prants, S. V.

    2001-07-01

    We consider one of the simplest semiclassical models in laser and atomic physics, a collection of two-level atoms interacting coherently with an electromagnetic standing wave in an ideal single-mode cavity within the rotating-wave approximation (RWA). In the strong-coupling limit, atoms and a cavity field constitute a strongly coupled atom-field dynamical system whose atomic and field variables oscillate in a self-consistent way with the Rabi frequency. It is proven analytically by the Melnikov method and numerically by computing maximal Lyapunov exponents and Poincaré sections that the parametric Rabi oscillations in a vibrating cavity may be chaotic in a sense of exponential sensitivity to initial conditions. Wavelet spectra computed with typical signals of the oscillations demonstrate clearly that Hamiltonian chaos in the coherent atom-field interaction with modulated coupling is structural. Structural chaos is characterized by positive values of the maximal Lyapunov exponents and regular structures which coexist in the same signal. Duration of a train of regular oscillations is defined by the period of modulation, but oscillations between successive trains are chaotic. Results of numerical experiments and estimation of the control parameters and approximations involved show that a Rydberg atom maser operating with a collection of two-level atoms inside a high-quality superconducting microwave cavity is a promising device for observing manifestations of structural Hamiltonian chaos in real experiments.

  2. Nonlinear interaction and wave breaking with a submerged porous structure

    NASA Astrophysics Data System (ADS)

    Hsieh, Chih-Min; Sau, Amalendu; Hwang, Robert R.; Yang, W. C.

    2016-12-01

    Numerical simulations are performed to investigate interactive velocity, streamline, turbulent kinetic energy, and vorticity perturbations in the near-field of a submerged offshore porous triangular structure, as Stokes waves of different heights pass through. The wave-structure interaction and free-surface breaking for the investigated flow situations are established based on solutions of 2D Reynolds Averaged Navier-Stokes equations in a Cartesian grid in combination with K-ɛ turbulent closure and the volume of fluid methodology. The accuracy and stability of the adopted model are ascertained by extensive comparisons of computed data with the existing experimental and theoretical findings and through efficient predictions of the internal physical kinetics. Simulations unfold "clockwise" and "anticlockwise" rotation of fluid below the trough and the crest of the viscous waves, and the penetrated wave energy creates systematic flow perturbation in the porous body. The interfacial growths of the turbulent kinetic energy and the vorticity appear phenomenal, around the apex of the immersed structure, and enhanced significantly following wave breaking. Different values of porosity parameter and two non-porous cases have been examined in combination with varied incident wave height to reveal/analyze the nonlinear flow behavior in regard to local spectral amplification and phase-plane signatures. The evolution of leading harmonics of the undulating free-surface and the vertical velocity exhibits dominating roles of the first and the second modes in inducing the nonlinearity in the post-breaking near-field that penetrates well below the surface layer. The study further suggests the existence of a critical porosity that can substantially enhance the wave-shoaling and interface breaking.

  3. Interaction of Lamb mode (A(o)) with structural discontinuity and generation of "Turning modes" in a T-joint.

    PubMed

    Ramadas, C; Balasubramaniam, Krishnan; Joshi, M; Krishnamurthy, C V

    2011-07-01

    In the present work, the interaction of the fundamental anti-symmetric guided Lamb mode (A(o)) with a structural discontinuity in a composite structure was studied through Finite Element numerical simulations and experiments. The structural component selected for this study was a T-joint section made from glass/epoxy material. This co-cured composite structure is made-up of an upper shell (skin) and a spar as the sub-components. It was observed that when A(o) mode interacts with the junction (structural discontinuity) of these sub-components, a mode-converted S(o) mode is generated. Experiments were conducted using air-coupled ultrasound to validate the numerical simulations. The back-propagating "Turning modes", which propagate from the thin region to the spar web and vice versa, were also numerically simulated and experimentally verified.

  4. A Structural Dynamics Approach to the Simulation of Spacecraft Control/Structure Interaction

    NASA Technical Reports Server (NTRS)

    Young, J. W.

    1985-01-01

    A relatively simple approach to the analysis of linear spacecraft control/structure interaction problems is presented. The approach uses a commercially available structural system dynamic analysis package for both controller and plant dynamics, thus obviating the need to transfer data between separate programs. The unilateral coupling between components in the control system block diagram is simulated using sparse matrix stiffness and damping elements available in the structural dynamic code. The approach is illustrated with a series of simple tutorial examples of a rigid spacecraft core with flexible appendages.

  5. Development of a structured undergraduate research experience: Framework and implications.

    PubMed

    Brown, Anne M; Lewis, Stephanie N; Bevan, David R

    2016-09-10

    Participating in undergraduate research can be a pivotal experience for students in life science disciplines. Development of critical thinking skills, in addition to conveying scientific ideas in oral and written formats, is essential to ensuring that students develop a greater understanding of basic scientific knowledge and the research process. Modernizing the current life sciences research environment to accommodate the growing demand by students for experiential learning is needed. By developing and implementing a structured, theory-based approach to undergraduate research in the life sciences, specifically biochemistry, it has been successfully shown that more students can be provided with a high-quality, high-impact research experience. The structure of this approach allowed students to develop novel, independent projects in a computational molecular modeling lab. Students engaged in an experience in which career goals, problem-solving skills, time management skills, and independence in a research lab were developed. After experiencing this approach to undergraduate research, students reported feeling challenged to think critically and prepared for future career paths. The approach allowed for a progressive learning environment where more undergraduate students could participate in publishable research. Future areas for development include implementation in a bench-top lab and extension to disciplines beyond biochemistry. In this study, it has been shown that utilizing the structured approach to undergraduate research could allow for more students to experience undergraduate research and develop into more confident, independent life scientists well prepared for graduate schools and professional research environments. © 2016 by The International Union of Biochemistry and Molecular Biology, 44(5):463-474, 2016.

  6. Structural Design Feasibility Study for the Global Climate Experiment

    SciTech Connect

    Lewin,K.F.; Nagy, J.

    2008-12-01

    Neon, Inc. is proposing to establish a Global Change Experiment (GCE) Facility to increase our understanding of how ecological systems differ in their vulnerability to changes in climate and other relevant global change drivers, as well as provide the mechanistic basis for forecasting ecological change in the future. The experimental design was initially envisioned to consist of two complementary components; (A) a multi-factor experiment manipulating CO{sub 2}, temperature and water availability and (B) a water balance experiment. As the design analysis and cost estimates progressed, it became clear that (1) the technical difficulties of obtaining tight temperature control and maintaining elevated atmospheric carbon dioxide levels within an enclosure were greater than had been expected and (2) the envisioned study would not fit into the expected budget envelope if this was done in a partially or completely enclosed structure. After discussions between NEON management, the GCE science team, and Keith Lewin, NEON, Inc. requested Keith Lewin to expand the scope of this design study to include open-field exposure systems. In order to develop the GCE design to the point where it can be presented within a proposal for funding, a feasibility study of climate manipulation structures must be conducted to determine design approaches and rough cost estimates, and to identify advantages and disadvantages of these approaches including the associated experimental artifacts. NEON, Inc requested this design study in order to develop concepts for the climate manipulation structures to support the NEON Global Climate Experiment. This study summarizes the design concepts considered for constructing and operating the GCE Facility and their associated construction, maintenance and operations costs. Comparisons and comments about experimental artifacts, construction challenges and operational uncertainties are provided to assist in selecting the final facility design. The overall goal

  7. Computer implementation of analysis and optimization procedures for control-structure interaction problems

    NASA Technical Reports Server (NTRS)

    Belvin, W. Keith; Park, K. C.

    1990-01-01

    Implementation aspects of control-structure interaction analysis and optimization by the staggered use of single-discipline analysis modules are discussed. The single-discipline modules include structural analysis, controller synthesis and optimization. The software modularity is maintained by employing a partitioned control-structure interaction analysis procedure, thus avoiding the need for embedding the single-discipline modules into a monolithic program. A software testbed has been constructed as a stand-alone analysis and optimization program and tested for its versatility and software modularity by applying it to the dynamic analysis and preliminary design of a prototype Earth Pointing Satellite. Experience with the in-core testbed program so far demonstrates that the testbed is efficient, preserves software modularity, and enables the analyst to choose a different set of algorithms, control strategies and design parameters via user software interfaces. Thus, the present software architecture is recommended for adoption by control-structure interaction analysts as a preliminary analysis and design tool.

  8. DISCOS- DYNAMIC INTERACTION SIMULATION OF CONTROLS AND STRUCTURES (IBM VERSION)

    NASA Technical Reports Server (NTRS)

    Frisch, H. P.

    1994-01-01

    The Dynamic Interaction Simulation of Controls and Structure (DISCOS) program was developed for the dynamic simulation and stability analysis of passive and actively controlled spacecraft. In the use of DISCOS, the physical system undergoing analysis may be generally described as a cluster of contiguous flexible structures (bodies) that comprise a mechanical system, such as a spacecraft. The entire system (spacecraft) or portions thereof may be either spinning or nonspinning. Member bodies of the system may undergo large relative excursions, such as those of appendage deployment or rotor/ stator motion. The general system of bodies is, by its inherent nature, a feedback system in which inertial forces (such as those due to centrifugal and Coriolis acceleration) and the restoring and damping forces are motion-dependent. The system may possess a control system in which certain position and rate errors are actively controlled through the use of reaction control jets, servomotors, or momentum wheels. Bodies of the system may be interconnected by linear or nonlinear springs and dampers, by a gimbal and slider block mechanism, or by any combination of these. The DISCOS program can be used to obtain nonlinear and linearized time response of the system, interaction constant forces in the system, total system resonance properties, and frequency domain response and stability information for the system. DISCOS is probably the most powerful computational tool to date for the computer simulation of actively controlled coupled multi-flexible-body systems. The program is not easy to understand and effectively apply, but is not intended for simple problems. The DISCOS user is expected to have extensive working knowledge of rigid-body and flexible-body dynamics, finite-element techniques, numerical methods, and frequency-domain analysis. Various applications of DISCOS include simulation of the Shuttle payload deployment/retrieval mechanism, solar panel array deployment, antenna

  9. Computational Modeling for Fluid-Porous Structure Interaction with Large Structural Deformation

    NASA Astrophysics Data System (ADS)

    Zakerzadeh, Rana; Zunino, Paolo

    2016-11-01

    In this work, we utilize numerical models to investigate the importance of poroelasticity in the interaction of blood flow with a porohyperelastic vessel wall, and to establish a connection between the apparent viscoelastic behavior of the structure part and the intramural filtration flow. The main novelty is in the design of a Nitsche's splitting strategy, which separates the fluid from the structure sub-problems for the Fluid-Porous Structure Interaction system undergoing large deformations. The general idea is to use this model to study the influence of different parameters on energy dissipation in a poroelastic medium. We also study a new benchmark test specifically designed to investigate the effect of poroelasticity on large deformations.

  10. Structural basis of ligand interaction with atypical chemokine receptor 3

    NASA Astrophysics Data System (ADS)

    Gustavsson, Martin; Wang, Liwen; van Gils, Noortje; Stephens, Bryan S.; Zhang, Penglie; Schall, Thomas J.; Yang, Sichun; Abagyan, Ruben; Chance, Mark R.; Kufareva, Irina; Handel, Tracy M.

    2017-01-01

    Chemokines drive cell migration through their interactions with seven-transmembrane (7TM) chemokine receptors on cell surfaces. The atypical chemokine receptor 3 (ACKR3) binds chemokines CXCL11 and CXCL12 and signals exclusively through β-arrestin-mediated pathways, without activating canonical G-protein signalling. This receptor is upregulated in numerous cancers making it a potential drug target. Here we collected over 100 distinct structural probes from radiolytic footprinting, disulfide trapping, and mutagenesis to map the structures of ACKR3:CXCL12 and ACKR3:small-molecule complexes, including dynamic regions that proved unresolvable by X-ray crystallography in homologous receptors. The data are integrated with molecular modelling to produce complete and cohesive experimentally driven models that confirm and expand on the existing knowledge of the architecture of receptor:chemokine and receptor:small-molecule complexes. Additionally, we detected and characterized ligand-induced conformational changes in the transmembrane and intracellular regions of ACKR3 that elucidate fundamental structural elements of agonism in this atypical receptor.

  11. Sequence and Structure Dependent DNA-DNA Interactions

    NASA Astrophysics Data System (ADS)

    Kopchick, Benjamin; Qiu, Xiangyun

    Molecular forces between dsDNA strands are largely dominated by electrostatics and have been extensively studied. Quantitative knowledge has been accumulated on how DNA-DNA interactions are modulated by varied biological constituents such as ions, cationic ligands, and proteins. Despite its central role in biology, the sequence of DNA has not received substantial attention and ``random'' DNA sequences are typically used in biophysical studies. However, ~50% of human genome is composed of non-random-sequence DNAs, particularly repetitive sequences. Furthermore, covalent modifications of DNA such as methylation play key roles in gene functions. Such DNAs with specific sequences or modifications often take on structures other than the canonical B-form. Here we present series of quantitative measurements of the DNA-DNA forces with the osmotic stress method on different DNA sequences, from short repeats to the most frequent sequences in genome, and to modifications such as bromination and methylation. We observe peculiar behaviors that appear to be strongly correlated with the incurred structural changes. We speculate the causalities in terms of the differences in hydration shell and DNA surface structures.

  12. Structural basis of ligand interaction with atypical chemokine receptor 3

    PubMed Central

    Gustavsson, Martin; Wang, Liwen; van Gils, Noortje; Stephens, Bryan S.; Zhang, Penglie; Schall, Thomas J.; Yang, Sichun; Abagyan, Ruben; Chance, Mark R.; Kufareva, Irina; Handel, Tracy M.

    2017-01-01

    Chemokines drive cell migration through their interactions with seven-transmembrane (7TM) chemokine receptors on cell surfaces. The atypical chemokine receptor 3 (ACKR3) binds chemokines CXCL11 and CXCL12 and signals exclusively through β-arrestin-mediated pathways, without activating canonical G-protein signalling. This receptor is upregulated in numerous cancers making it a potential drug target. Here we collected over 100 distinct structural probes from radiolytic footprinting, disulfide trapping, and mutagenesis to map the structures of ACKR3:CXCL12 and ACKR3:small-molecule complexes, including dynamic regions that proved unresolvable by X-ray crystallography in homologous receptors. The data are integrated with molecular modelling to produce complete and cohesive experimentally driven models that confirm and expand on the existing knowledge of the architecture of receptor:chemokine and receptor:small-molecule complexes. Additionally, we detected and characterized ligand-induced conformational changes in the transmembrane and intracellular regions of ACKR3 that elucidate fundamental structural elements of agonism in this atypical receptor. PMID:28098154

  13. Numerical Modelling of Wave Interaction with Porous Structures

    NASA Astrophysics Data System (ADS)

    Gao, F.; M., D.; M., D.; G., C.

    This paper presents a numerical model for simulating wave interaction with porous structures. By using the free surface-capturing approach together with a novel Cartesian cut cell treatment, the Finite Volume Model calculates the two phase flows out side of porous structure based on the Navier-Stokes equations, while the flow in the porous structure is described by Navier-Stokes type model equations. The free surface of water is treated as a contact discontinuity in the density field which is captured automatically as part of the numerical solution by using a time-accurate artificial compressibility method and high resolution Godunov-type scheme. The numerical model is first calibrated by simple test for a steady flow passing through a porous block. Reasonably good agreements with other numerical results are obtained. After that, the numerical model is used to simulate the breaking wave overtopping a caisson breakwater, protected by a layer of armor units. The results show that the porous armor layer is effective in reducing the overtopping rate as well as in protecting the stability of the caisson breakwater.

  14. Interactive Internet delivery of scientific visualization via structured prerendered imagery

    NASA Astrophysics Data System (ADS)

    Chen, Jerry; Bethel, E. Wes; Yoon, Ilmi

    2006-01-01

    In this paper, we explore leveraging industry-standard media formats to effectively deliver interactive, 3D scientific visualization to a remote viewer. Our work is motivated by the need for remote visualization of time-varying, 3D data produced by scientific simulations or experiments while taking several practical factors into account, including: maximizing ease of use from the user's perspective, maximizing reuse of image frames, and taking advantage of existing software infrastructure wherever possible. Visualization or graphics applications first generate images at some number of view orientations for 3D scenes and temporal locations for time-varying scenes. We then encode the resulting imagery into one of two industry-standard formats: QuickTime VR Object Movies or a combination of HTML and JavaScript code implementing the client-side navigator. Using an industry-standard QuickTime player or web browser, remote users may freely navigate through the pre-rendered images of time-varying, 3D visualization output. Since the only inputs consist of image data, a viewpoint and time stamps, our approach is generally applicable to all visualization and graphics rendering applications capable of generating image files in an ordered fashion. Our design is a form of latency-tolerant remote visualization infrastructure where processing time for visualization, rendering and content delivery is effectively decoupled from interactive exploration. Our approach trades off increased interactivity, reduced load and effective reuse of coherent frames between multiple users (from the server's perspective) at the expense of unconstrained exploration. This paper presents the system architecture along with an analysis and discussion of its strengths and limitations.

  15. 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

  16. Structure and interactions in isotropic and liquid crystalline neurofilament networks

    NASA Astrophysics Data System (ADS)

    Jones, Jayna Bea

    2007-12-01

    Neurofilaments (NFs) are cytoskeletal proteins that are localized within nerve cells, which form long oriented bundles running the length of axons. While abnormal aggregations of these proteins have been implicated in several neurological disorders including Parkinson's disease and ALS, interfilament interactions in both the normal and diseased states are not well understood. In vivo, NFs are supramolecular structures composed of three subunit proteins of low (NF-L), medium (NF-M), and high molecular (NF-H) weight that assemble into a 10 nm diameter rod with radiating sidearms, forming a bottle-brush conformation. In this study we alter the subunit composition and probe the resulting networks with polarized microscopy and synchrotron small angle x-ray scattering (SAXS), in order to isolate the role of each subunit in interfilament interactions. By reassembling NFs in vitro from varying ratios of the subunit proteins, purified from bovine spinal cord, we form filaments with controlled subunit compositions. The resulting filaments, at a high volume fraction, are nematic liquid crystalline gels with a well defined spacing, determined with SAXS. Upon dilution the difference between the subunits is realized with NF-M grafted filaments being dominated by attractive interactions and remaining aligned, while those flanked with NF-H sidearms repel and become isotropic gels. Interplay between these forces is seen in the ternary system composed of all three subunit proteins (NF-LMH). The polyampholytic subunits have a charge distribution that varies along the length of the sidearm, which forms the brush layer, and the distribution is different for each subunit. The interfilament interactions are highly dependent on environmental conditions including salt concentration, pH, and osmotic pressure. Increasing ionic strength induces attractive interactions and a stabilization of the nematic phase in filaments that were repulsive at lower monovalent salt concentration. The

  17. CrashEd--A Live Immersive, Learning Experience Embedding STEM Subjects in a Realistic, Interactive Crime Scene

    ERIC Educational Resources Information Center

    Bassford, Marie L.; Crisp, Annette; O'Sullivan, Angela; Bacon, Joanne; Fowler, Mark

    2016-01-01

    Interactive experiences are rapidly becoming popular via the surge of "escape rooms"; part game and part theatre, the "escape" experience is exploding globally, having gone from zero offered at the outset of 2010 to at least 2800 different experiences available worldwide today. CrashEd is an interactive learning experience that…

  18. Measurements of mixing layer height variability during the Ligurian air-sea interaction experiment (LASIE '07)

    NASA Astrophysics Data System (ADS)

    Förster, J.

    2009-09-01

    Air-sea interaction processes play a dominant role with respect to detection ranges of shipborne radar and infrared sensor systems. Especially in the littoral most often temperature and humidity gradients affect propagation paths and are the reason for abnormal phenomena such as ducting or mirage. Besides refractivity, spray and aerosols ejected from the sea surface can further degrade the quality of shipborne surveillance systems. Thus environmental effects might seriously hamper ship self defense. During the Ligurian Air-Sea Interaction Experiment (LASIE '07 - 16.06.-26.06.2007) the Federal Armed Forces Underwater Acoustics and Marine Geophysics Research Institute (FWG) carried out simultaneous in-situ measurements of meteorological and oceanographic parameters to study air-sea interaction processes with respect to littoral boundary layer variability. The characterization of the environment included both, in-situ measurements of atmospheric and sea surface parameters. Investigations were carried out on board RV PLANET, RV URANIA and at the ODAS-Italy1 buoy of the Italian National Council of Research (CNR). On board RV PLANET the sea surface and meteorological conditions were analyzed by two multi-sensor buoys, ship sensors and radiosondes. Emphasis was given to the vertical structure of the Marine Boundary Layer (MBL) and its variability. It was analyzed by a one lense lidar ceilometer CL31, a tethersonde system TT12 and radiosondes RS92 (Vaisala). The latter were launched every three hours. The TT12 consisted of three radiosondes, which could be adapted to separate altitudes of special interest. The experiment was characterized by changing meteorological conditions resulting in offshore and onshore blowing winds. In the first case the air temperature TAir was higher than the sea surface temperature TWater leading to a very stable surface layer. This situation was associated with a strong temperature inversion and a very clear atmosphere with a visibility of

  19. State Effect of Traumatic Experience on Personality Structure

    PubMed Central

    Lee, Hong-seock; Lee, Sang-Kyu; Lee, Heung-Pyo

    2012-01-01

    Objective Personality is defined as the trait-like qualities of a person. However, it has been recently suggested that the state effect of a situation leads to changes in scores on personality assessments. We predicted that traumatic experiences would induce changes not only in personality scores but also in the factor structures of personality assessments. Methods MethodsaaWe conducted a cross-sectional, case-controlled study using two data sets: a traumatized adolescent sample (n=71) and a non-traumatized adolescent sample (n=296). Personality factor structures were compared between the two samples using exploratory factor analyses for 25 lower-ordered subscales of the Temperament and Character Inventory (TCI). In the non-traumatized sample, evaluation of the scree plot suggested a five-factor solution supporting TCI's original seven-factor model. Results The traumatized sample showed a three-factor structure representing a biological factor, a social factor and an existential factor. This decrease in number of personality factors was caused by strengthened correlations among personality subscales related to coping with traumatic situations. Cloninger's psychobiological model of personality (i.e., temperament-character) was adequate in capturing personality traits of non-traumatized adolescents, but the tripartite view of existential psychology (i.e., body-mind-spirit) clearly corresponded to the factor structure of the traumatized adolescents. Conclusion The three-factor solution of the present traumatized group is consistent with the tripartite model of personality (i.e., body-mind-spirit), while the five-factor solution of the non-traumatized group corresponds to Cloninger's seven-factor model. This is the first study to describe the state effects of traumatic experiences on personality structure. PMID:23251200

  20. RF ACCELERATING STRUCTURE FOR THE MUON COOLING EXPERIMENT.

    SciTech Connect

    CORLETT,J.; GREEN,M.; LI,D.; HOLTKAMP,N.; MORETTI,A.; KIRK,H.G.; PALMER,R.B.; ZHAO,Y.; SUMMERS,D.

    1999-03-29

    The ionization cooling of muons requires longitudinal acceleration of the muons after scattering in a hydrogen target. In order to maximize the accelerating voltage, we propose using linear accelerating structures with cells bounded by thin beryllium metal foils. This produces an on-axis field equivalent to the maximum surface field, whereas with beam-pipes the accelerating field is approximately half that of the peak surface field in the cavity. The muons interact only weakly with the thin foils. A {pi}/2 interleaved cavity structure has been chosen, with alternate cells coupled together externally, and the two groups of cells fed in quadrature. At present they are considering an operating temperature of 77K to gain a factor of at least two in Q-value over room temperature. The authors describe the design of the {pi}/2 interleaved cavity structure, design of an alternative {pi}-mode open structure, preliminary experimental results from a low-power test cavity, and plans for high-power testing.

  1. Glycyl radical activating enzymes: structure, mechanism, and substrate interactions.

    PubMed

    Shisler, Krista A; Broderick, Joan B

    2014-03-15

    The glycyl radical enzyme activating enzymes (GRE-AEs) are a group of enzymes that belong to the radical S-adenosylmethionine (SAM) superfamily and utilize a [4Fe-4S] cluster and SAM to catalyze H-atom abstraction from their substrate proteins. GRE-AEs activate homodimeric proteins known as glycyl radical enzymes (GREs) through the production of a glycyl radical. After activation, these GREs catalyze diverse reactions through the production of their own substrate radicals. The GRE-AE pyruvate formate lyase activating enzyme (PFL-AE) is extensively characterized and has provided insights into the active site structure of radical SAM enzymes including GRE-AEs, illustrating the nature of the interactions with their corresponding substrate GREs and external electron donors. This review will highlight research on PFL-AE and will also discuss a few GREs and their respective activating enzymes.

  2. Structure Formation Mechanisms during Solid Ti with Molten Al Interaction

    NASA Astrophysics Data System (ADS)

    Gurevich, L.; Pronichev, D.; Trunov, M.

    2016-02-01

    The study discuses advantages and disadvantages of previously proposed mechanisms of the formation of structure between solid Ti and molten Al and presents a new mechanism based on the reviewed and experimental data. The previously proposed mechanisms were classified into three groups: mechanisms of precipitation, mechanisms of destruction and mechanisms of chemical interaction between intermetallics and melt. The reviewed mechanisms did not explain the formation of heterogeneous interlayer with globular aluminide particles and thin layers of pure Al, while the present study reveals variation in the solid Ti/molten Al reaction kinetics during various phases of laminated metal-intermetallic composite formation. The proposed mechanism considers formed during composite fabrication thin oxide interlayers between Ti and Al evolution and its impact on the intermetallic compound formation and explains the initial slow rate of intermetallic interlayer formation and its subsequent acceleration when the oxide foils are ruptured.

  3. Solution structures and molecular interactions of selective melanocortin receptor antagonists.

    PubMed

    Lee, Chul-Jin; Yun, Ji-Hye; Lim, Sung-Kil; Lee, Weontae

    2010-12-01

    The solution structures and inter-molecular interaction of the cyclic melanocortin antagonists SHU9119, JKC363, HS014, and HS024 with receptor molecules have been determined by NMR spectroscopy and molecular modeling. While SHU9119 is known as a nonselective antagonist, JKC363, HS014, and HS024 are selective for the melanocortin subtype-4 receptor (MC4R) involved in modulation of food intake. Data from NMR and molecular dynamics suggest that the conformation of the Trp9 sidechain in the three MC4R-selective antagonists is quite different from that of SHU9119. This result strongly supports the concept that the spatial orientation of the hydrophobic aromatic residue is more important for determining selectivity than the presence of a basic, "arginine-like" moiety responsible for biological activity. We propose that the conformation of hydrophobic residues of MCR antagonists is critical for receptor-specific selectivity.

  4. Species interactions and the structure of complex communication networks

    PubMed Central

    Tobias, Joseph A.; Planqué, Robert; Cram, Dominic L.; Seddon, Nathalie

    2014-01-01

    A universal challenge faced by animal species is the need to communicate effectively against a backdrop of heterospecific signals. It is often assumed that this need results in signal divergence to minimize interference among community members, yet previous support for this idea is mixed, and few studies have tested the opposing hypothesis that interactions among competing species promote widespread convergence in signaling regimes. Using a null model approach to analyze acoustic signaling in 307 species of Amazonian birds, we show that closely related lineages signal together in time and space and that acoustic signals given in temporal or spatial proximity are more similar in design than expected by chance. These results challenge the view that multispecies choruses are structured by temporal, spatial, or acoustic partitioning and instead suggest that social communication between competing species can fundamentally organize signaling assemblages, leading to the opposite pattern of clustering in signals and signaling behavior. PMID:24395769

  5. Microcosm experiments to study the interaction of solid and solute phases during initial soil development

    NASA Astrophysics Data System (ADS)

    Zimmermann, C.; Chabbi, S.; Schaaf, W.

    2009-04-01

    During the initial phase of soil formation mineral weathering, interactions between the solid and liquid phases as well as accumulation of organic matter play an important role for the development of soil properties and for the establishment of vegetation and the colonization of soil biota. Our study is part of the Transregional Collaborative Research Centre (SFB/TRR 38) ‘Patterns and processes of initial ecosystem development in an artificial catchment' funded by the Deutsche Forschungsgemeinschaft (DFG). The catchment ´Chicken Creeḱ close to Cottbus (Germany) has a size of 6 ha and is composed of a 3-4 m layer of Quaternary loamy to sandy sediments overlying a 1-2 m clay layer. To connect interactions between the soil solid phase and soil solution at the micro-scale with observed processes at the catchment scale we perform microcosm experiments with soil samples from the catchment under controlled laboratory conditions. The microcosm experiments are carried out in a climate chamber at constant 10 °C corresponding to the mean annual temperature of the region. In total 48 soil columns with a diameter of 14.4 cm and height of 30 cm were filled with substrates of two textural compositions reflecting the gradients observed at the catchment and a bulk density of 1.4-1.5 g*cm3. Within the microcosms it is possible to control the gaseous phase and the water fluxes by artificial irrigation. The irrigation runs automated and quasi-continuously four times a day with 6.6 ml each (in total 600 mm*yr-1). Irrigation amount and chemical composition of the artificial rainwater are based on the annual mean at the field site. Litter of two different plant species occurring at the catchment site (Lotus corniculatus, Calamagrostis epigejos) labelled with stable isotopes (δ13C; δ15N) is used for the experiments. All treatments including a control run with four replicates. The gaseous phase in the headspace of the microcosms is analysed continuously for CO2 and N2O contents

  6. Investigating Intermolecular Interactions via Scanning Tunneling Microscopy: An Experiment for the Physical Chemistry Laboratory

    ERIC Educational Resources Information Center

    Pullman, David; Peterson, Karen I.

    2004-01-01

    A scanning tunneling microscope (STM) project designed as a module for the undergraduate physical chemistry laboratory is described. The effects of van der Waals interactions on the condensed-phase structure are examined by the analysis of the pattern of the monolayer structures.

  7. On the characteristics of tidal structures of interacting galaxies

    NASA Astrophysics Data System (ADS)

    Mohamed, Y. H.; Reshetnikov, V. P.; Sotnikova, N. Ya.

    2011-10-01

    We present the results of our analysis of the geometrical tidal tail characteristics for nearby and distant interacting galaxies. The sample includes more than two hundred nearby galaxies and about seven hundred distant ones. The distant galaxies have been selected in several deep fields of the Hubble Space Telescope (HDF-N, HDF-S, HUDF, GOODS, GEMS) and they are at mean redshift < z> = 0.65. We analyze the distributions of lengths and thicknesses for the tidal structures and show that the tails in distant galaxies appear shorter than those in nearby ones. This effect can be partly attributed to observational selection, but, on the other hand, it may result from the general evolution of the sizes of spiral galaxies with z. The positions of interacting galaxies on the galaxy luminosity ( L)-tidal tail length ( l) plane are shown to be explained by a simple geometrical model, with the upper envelope of the observed distribution being l ∝ sqrt L. We have solved the problem on the relationship between the observed distribution of tail flatting and the tail length in angular measure by assuming the tidal tails to be arcs of circumferences visible at arbitrary angles to the line of sight. We conclude that the angular length of the tidal tails visually distinguished in nearby and distant galaxies, on average, exceeds 180°.

  8. Computational modeling of fluid structural interaction in arterial stenosis

    NASA Astrophysics Data System (ADS)

    Bali, Leila; Boukedjane, Mouloud; Bahi, Lakhdar

    2013-12-01

    Atherosclerosis affects the arterial blood vessels causing stenosis because of which the artery hardens resulting in loss of elasticity in the affected region. In this paper, we present: an approach to model the fluid-structure interaction through such an atherosclerosis affected region of the artery, The blood is assumed as an incompressible Newtonian viscous fluid, and the vessel wall was treated as a thick-walled, incompressible and isotropic material with uniform mechanical properties. The numerical simulation has been studied in the context of The Navier-Stokes equations for an interaction with an elastic solid. The study of fluid flow and wall motion was initially carried out separately, Discretized forms of the transformed wall and flow equations, which are coupled through the boundary conditions at their interface, are obtained by control volume method and simultaneously to study the effects of wall deformability, solutions are obtained for both rigid and elastic walls. The results indicate that deformability of the wall causes an increase in the time average of pressure drop, but a decrease in the maximum wall shear stress. Displacement and stress distributions in the wall are presented.

  9. Interaction of guided waves with delaminations in composite plate structures

    NASA Astrophysics Data System (ADS)

    Gupta, Saurabh; Yu, Xudong; Fan, Zheng; Rajagopal, Prabhu

    2017-02-01

    This paper addresses a gap in the literature on the 3-dimensional scattering of the fundamental symmetric Lamb mode S0 from delimitations in composite plates. We study the scattering of low-frequency S0 Lamb mode from a delamination in a stiffened 4-ply CFRP composite plate with [0/0]S ply orientation. Far field scattering coefficients for the S0 Lamb mode are plotted as a function of circumferential position around the delamination using 3D FE simulations. Results show that the delamination size has less influence on S0 Lamb wave scattering in the low-frequency regime where the S0 mode is non-dispersive. Further analysis was done using two-dimensional FE simulation for different ply-layup orientations with S0 Lamb mode. This study shows that ply-layup orientation and through-thickness delamination location in fiber composite laminate have a significant influence on S0 Lamb mode interaction. We also analyzed the interaction of A0 Lamb mode for a few cases. This work will be useful for practical Lamb wave based inspection of composite plate structures.

  10. Shallow lunar structure determined from the passive seismic experiment

    NASA Technical Reports Server (NTRS)

    Nakamura, Y.; Dorman, J.; Duennebier, F.; Lammlein, D.; Latham, G.

    1975-01-01

    Data relevant to the shallow structure of the moon obtained at the Apollo seismic stations are compared with previously published results of the active seismic experiments. It is concluded that the lunar surface is covered by a layer of low seismic velocity which appears to be equivalent to the lunar regolith defined previously by geological observations. This layer is underlain by a zone of distinctly higher seismic velocity at all of the Apollo landing sites. The regolith thicknesses at the Apollo 11, 12, and 15 sites are estimated from the shear-wave resonance to be 4.4, 3.7, and 4.4 m, respectively. These thicknesses and those determined at the other Apollo sites by the active seismic experiments appear to be correlated with the age determinations and the abundances of extralunar components at the sites.

  11. Frequency domain identification experiment on a large flexible structure

    NASA Technical Reports Server (NTRS)

    Bayard, D. S.; Hadaegh, F. Y.; Yam, Y.; Scheid, R. E.; Mettler, E.; Milman, M. H.

    1989-01-01

    Recent experiences in the field of flexible structure control in space have indicated a need for on-orbit system identification to support robust control redesign to avoid in-flight instabilities and maintain high spacecraft performance. The authors highlight an automated frequency domain system identification methodology recently developed to fill this need. The methodology supports (1) the estimation of system quantities useful for robust control analysis and design, (2) experiment design tailored to performing system identification in a typically constrained on-orbit environment, and (3) the automation of operations to reduce human-in-the-loop requirements. A basic overview of the methodology is presented first, followed by an experimental verification of the approach performed on the JPL/AFAL testbed facility.

  12. Chaotic dynamics and fractal structures in experiments with cold atoms

    NASA Astrophysics Data System (ADS)

    Daza, Alvar; Georgeot, Bertrand; Guéry-Odelin, David; Wagemakers, Alexandre; Sanjuán, Miguel A. F.

    2017-01-01

    We use tools from nonlinear dynamics for the detailed analysis of cold-atom experiments. A powerful example is provided by the recent concept of basin entropy, which allows us to quantify the final-state unpredictability that results from the complexity of the phase-space geometry. We show here that this enables one to reliably infer the presence of fractal structures in phase space from direct measurements. We illustrate the method with numerical simulations in an experimental configuration made of two crossing laser guides that can be used as a matter-wave splitter.

  13. The Plasma Interaction Experiment /PIX/ - Description and flight qualification test program

    NASA Technical Reports Server (NTRS)

    Ignaczak, L. R.; Haley, F. A.; Domino, E. J.; Culp, D. H.; Shaker, F. J.

    1978-01-01

    The Plasma Interaction Experiment (PIX) is a battery powered preprogrammed auxiliary payload on the Landsat-C launch. This experiment is part of a larger program to investigate space plasma interactions with spacecraft surfaces and components. The varying plasma densities encountered during available telemetry coverage periods are deemed sufficient to determine first order interactions between the space plasma environment and the biased experimental surfaces. The specific objectives of the PIX flight experiment are to measure the plasma coupling current and the negative voltage breakdown characteristics of a solar array segment and a gold plated steel disk. Measurements will be made over a range of surface voltages up to plus or minus 1 kilovolt. The orbital environment will provide a range of plasma densities. The experimental surfaces will be voltage-biased in a preprogrammed step sequence to optimize the data returned for each plasma region and for the available telemetry coverage.

  14. 3Drefine: an interactive web server for efficient protein structure refinement

    PubMed Central

    Bhattacharya, Debswapna; Nowotny, Jackson; Cao, Renzhi; Cheng, Jianlin

    2016-01-01

    3Drefine is an interactive web server for consistent and computationally efficient protein structure refinement with the capability to perform web-based statistical and visual analysis. The 3Drefine refinement protocol utilizes iterative optimization of hydrogen bonding network combined with atomic-level energy minimization on the optimized model using a composite physics and knowledge-based force fields for efficient protein structure refinement. The method has been extensively evaluated on blind CASP experiments as well as on large-scale and diverse benchmark datasets and exhibits consistent improvement over the initial structure in both global and local structural quality measures. The 3Drefine web server allows for convenient protein structure refinement through a text or file input submission, email notification, provided example submission and is freely available without any registration requirement. The server also provides comprehensive analysis of submissions through various energy and statistical feedback and interactive visualization of multiple refined models through the JSmol applet that is equipped with numerous protein model analysis tools. The web server has been extensively tested and used by many users. As a result, the 3Drefine web server conveniently provides a useful tool easily accessible to the community. The 3Drefine web server has been made publicly available at the URL: http://sysbio.rnet.missouri.edu/3Drefine/. PMID:27131371

  15. Controls-structures interaction guest investigator program: Overview and phase 1 experimental results and future plans

    NASA Technical Reports Server (NTRS)

    Smith-Taylor, Rudeen; Tanner, Sharon E.

    1993-01-01

    The NASA Controls-Structures Interaction (CSI) Guest Investigator program is described in terms of its support of the development of CSI technologies. The program is based on the introduction of CSI researchers from industry and academia to available test facilities for experimental validation of technologies and methods. Phase 1 experimental results are reviewed with attention given to their use of the Mini-MAST test facility and the facility for the Advance Control Evaluation of Structures. Experiments were conducted regarding the following topics: collocated/noncollocated controllers, nonlinear math modeling, controller design, passive/active suspension systems design, and system identification and fault isolation. The results demonstrate that significantly enhanced performance from the control techniques can be achieved by integrating knowledge of the structural dynamics under consideration into the approaches.

  16. Towards a mechanistic understanding of temperature and enrichment effects on species interaction strength, omnivory and food-web structure.

    PubMed

    Sentis, Arnaud; Hemptinne, Jean-Louis; Brodeur, Jacques

    2014-07-01

    Revealing the links between species functional traits, interaction strength and food-web structure is of paramount importance for understanding and predicting the relationships between food-web diversity and stability in a rapidly changing world. However, little is known about the interactive effects of environmental perturbations on individual species, trophic interactions and ecosystem functioning. Here, we combined modelling and laboratory experiments to investigate the effects of warming and enrichment on a terrestrial tritrophic system. We found that the food-web structure is highly variable and switches between exploitative competition and omnivory depending on the effects of temperature and enrichment on foraging behaviour and species interaction strength. Our model contributes to identifying the mechanisms that explain how environmental effects cascade through the food web and influence its topology. We conclude that considering environmental factors and flexible food-web structure is crucial to improve our ability to predict the impacts of global changes on ecosystem diversity and stability.

  17. Electronic structure of polyimide and related monomers: Theory and experiment

    NASA Astrophysics Data System (ADS)

    Kowalczyk, Steven P.; Stafström, Sven; Brédas, J. L.; Salaneck, William R.; Jordan-Sweet, Jean L.

    1990-01-01

    The electronic structure of polymide and several related compounds was investigated theoretically and experimentally. The compounds include pyromellitic dianhydride, oxydianiline, and polyamic acid. Experimental electronic-structure determinations for poly(methyl phenylene oxide) and poly(vinyl methyl ketone) are also reported. The theoretical approach employed valence-effective-Hamiltonian calculations. Photoelectron spectroscopy (x-ray photoelectron spectroscopy, soft-x-ray photoelectron spectroscopy, and ultraviolet photoelectron spectroscopy) was used to experimentally measure the total valence-band density of states (VBDOS) from thin films of the above compounds. The theoretical VBDOS's were cross-section modulated to facilitate comparison with experiment. Very good agreement is found between the theoretical results and the experimental VBDOS's.

  18. Structure and Electronic Properties of Cerium Orthophosphate: Theory and Experiment

    SciTech Connect

    Adelstein, Nicole; Mun, B. Simon; Ray, Hannah; Ross Jr, Phillip; Neaton, Jeffrey; De Jonghe, Lutgard

    2010-07-27

    Structural and electronic properties of cerium orthophosphate (CePO{sub 4}) are calculated using density functional theory (DFT) with the local spin-density approximation (LSDA+U), with and without gradient corrections (GGA-(PBE)+U), and compared to X-ray diffraction and photoemission spectroscopy measurements. The density of states is found to change significantly as the Hubbard parameter U, which is applied to the Ce 4f states, is varied from 0 to 5 eV. The calculated structural properties are in good agreement with experiment and do not change significantly with U. Choosing U = 3 eV for LDSA provides the best agreement between the calculated density of states and the experimental photoemission spectra.

  19. Fluid-structure interaction-based biomechanical perception model for tactile sensing.

    PubMed

    Wang, Zheng

    2013-01-01

    The reproduced tactile sensation of haptic interfaces usually selectively reproduces a certain object attribute, such as the object's material reflected by vibration and its surface shape by a pneumatic nozzle array. Tactile biomechanics investigates the relation between responses to an external load stimulus and tactile perception and guides the design of haptic interface devices via a tactile mechanism. Focusing on the pneumatic haptic interface, we established a fluid-structure interaction-based biomechanical model of responses to static and dynamic loads and conducted numerical simulation and experiments. This model provides a theoretical basis for designing haptic interfaces and reproducing tactile textures.

  20. Holographic particle velocimetry - A 3D measurement technique for vortex interactions, coherent structures and turbulence

    NASA Astrophysics Data System (ADS)

    Meng, Hui; Hussain, Fazle

    1991-10-01

    To understand the topology and dynamics of coherent structures (CS), the interactions of CS with fine-scale turbulence, and the effects of CS on entrainment, mixing and combustion, experimental tools are needed that can measure velocity (preferably vorticity) vector fields in both 3D space and time. While traditional measurement techniques are not able to serve this purpose, holographic particle velocimetry (HPV) appears to be promising. In a demonstration experiment, the instantaneous 3D velocity vector fields in some simple vortical flows have been obtained using the HPV technique. In this preliminary report, the principles of the HPV technique are illustrated and the key issues in its implementation are discussed.

  1. Fluid–Structure Interaction-Based Biomechanical Perception Model for Tactile Sensing

    PubMed Central

    Wang, Zheng

    2013-01-01

    The reproduced tactile sensation of haptic interfaces usually selectively reproduces a certain object attribute, such as the object's material reflected by vibration and its surface shape by a pneumatic nozzle array. Tactile biomechanics investigates the relation between responses to an external load stimulus and tactile perception and guides the design of haptic interface devices via a tactile mechanism. Focusing on the pneumatic haptic interface, we established a fluid–structure interaction-based biomechanical model of responses to static and dynamic loads and conducted numerical simulation and experiments. This model provides a theoretical basis for designing haptic interfaces and reproducing tactile textures. PMID:24260228

  2. How to conduct and interpret ITC experiments accurately for cyclodextrin-guest interactions.

    PubMed

    Bouchemal, Kawthar; Mazzaferro, Silvia

    2012-06-01

    Isothermal titration calorimetry (ITC) is one of the most interesting methods for the characterization of the interaction mechanisms of cyclodextrins (CDs) with drugs. In this review we explain how to conduct ITC experiments correctly for CD-guest interactions, how to choose an accurate fitting model for the titration curve and how to interpret carefully the ITC results. Finally, the use of ITC for the characterization of CD-containing nanoparticles is discussed.

  3. Laboratory plasma interactions experiments: Results and implications to future space systems

    NASA Technical Reports Server (NTRS)

    Leung, Philip

    1986-01-01

    The experimental results discussed show the significance of the effects caused by spacecraft plasma interactions, in particular the generation of Electromagnetic Interference. As the experimental results show, the magnitude of the adverse effects induced by Plasma Interactions (PI) will be more significant for spacecraft of the next century. Therefore, research is needed to control possible adverse effects. Several techniques to control the selected PI effects are discussed. Tests, in the form of flight experiments, are needed to validate these proposed ideas.

  4. Electronic Structure Theory for Radicaloid Systems and Intermolecular Interactions

    NASA Astrophysics Data System (ADS)

    Kurlancheek, Westin

    A radical molecule contains one or more electrons that are unpaired. A radicaloid may be defined as a molecule in which there are that are partially unpaired. As a result, the electronic structure of the radicaloid can be quite complicated for a variety of reasons. For a singlet biradicaloid, the singlet and triplet wavefunction can be quite close energetically which can lead to problems when trying to describe the system with a single determinant. The simplest solution to this problem is to allow the wavefunction to break spin-symmetry in order to get a lower energy. Unfortunately this action can lead to wavefunctions that are no longer eigenfunctions of the < S2> operator. In the second chapter we investigate a distannyne which has a biradicaloid resonance structure. By examining the orbital Hessian, it is discovered that the spin-symmetric solution is a saddle-point in wavefunction space and is structurally different than the spin-polarized solution. We then increase the complexity of the model system and see that the spin-symmetric solution is only a minimum for the exact experimental system and not for a simplified model system in which bulky organic substituents are replaced by simpler phenyl groups. Therefore, the breaking of spin-symmetry is absolutely critical in the small model systems and the full substituents play a non-trivial role. However, the breaking of the spin-symmetry can have consequences for physical quantities when correlated methods are used. At the point of spin polarization or unrestriction the orbital Hessian will have one eigenvalue which is zero. Since the relaxed density matrix in correlated methods like Second-Order Mo ller-Plesset theory (MP2) depend on the inverse of the Hessian, at the unrestriction point this quantity will be undefined. Some unphysical artifacts are identified as a direct consequence of this fact. First, discontinuities in first order molecular properties such as the dipole moment are seen at the geometries

  5. Prediction of protein-protein interactions: unifying evolution and structure at protein interfaces.

    PubMed

    Tuncbag, Nurcan; Gursoy, Attila; Keskin, Ozlem

    2011-06-01

    The vast majority of the chores in the living cell involve protein-protein interactions. Providing details of protein interactions at the residue level and incorporating them into protein interaction networks are crucial toward the elucidation of a dynamic picture of cells. Despite the rapid increase in the number of structurally known protein complexes, we are still far away from a complete network. Given experimental limitations, computational modeling of protein interactions is a prerequisite to proceed on the way to complete structural networks. In this work, we focus on the question 'how do proteins interact?' rather than 'which proteins interact?' and we review structure-based protein-protein interaction prediction approaches. As a sample approach for modeling protein interactions, PRISM is detailed which combines structural similarity and evolutionary conservation in protein interfaces to infer structures of complexes in the protein interaction network. This will ultimately help us to understand the role of protein interfaces in predicting bound conformations.

  6. Fluid Structure Interaction Simulations of Pediatric Ventricular Assist Device Operation

    NASA Astrophysics Data System (ADS)

    Long, Chris; Marsden, Alison; Bazilevs, Yuri

    2011-11-01

    Pediatric ventricular assist devices (PVADs) are used for mechanical circulatory support in children with failing hearts. They can be used to allow the heart to heal naturally or to extend the life of the patient until transplant. A PVAD has two chambers, blood and air, separated by a flexible membrane. The air chamber is pressurized, which drives the membrane and pumps the blood. The primary risk associated with these devices is stroke or embolism from thrombogenesis. Simulation of these devices is difficult due to a complex coupling of two fluid domains and a thin membrane, requiring fluid-structure interaction modeling. The goal of this work is to accurately simulate the hemodynamics of a PVAD. We perform FSI simulations using an Arbitrary Lagrangian-Eulerian (ALE) finite element framework to account for large motions of the membrane and the fluid domains. The air, blood, and membrane are meshed as distinct subdomains, and a method for non-matched discretizations at the fluid-structure interface is presented. The use of isogeometric analysis to model the membrane mechanics is also discussed, and the results of simulations are presented.

  7. Molecular Structures and Interactions in the Yeast Kinetochore

    PubMed Central

    Cho, U.-S.; Corbett, K.D.; Al-Bassam, J.; Bellizzi, J.J.; De Wulf, P.; Espelin, C.W.; Miranda, J.J.; Simons, K.; Wei, R.R.; Sorger, P.K.; Harrison, S.C.

    2011-01-01

    Kinetochores are the elaborate protein assemblies that attach chromosomes to spindle microtubules in mitosis and meiosis. The kinetochores of point-centromere yeast appear to represent an elementary module, which repeats a number of times in kinetochores assembled on regional centromeres. Structural analyses of the discrete protein subcomplexes that make up the budding-yeast kinetochore have begun to reveal principles of kinetochore architecture and to uncover molecular mechanisms underlying functions such as transmission of tension and establishment and maintenance of bipolar attachment. The centromeric DNA is probably wrapped into a compact organization, not only by a conserved, centromeric nucleosome, but also by interactions among various other DNA-bound kinetochore components. The rod-like, heterotetrameric Ndc80 complex, roughly 600 Å long, appears to extend from the DNA-proximal assembly to the plus end of a microtubule, to which one end of the complex is known to bind. Ongoing structural studies will clarify the roles of a number of other well-defined complexes. PMID:21467141

  8. Interactions in Bacterial Biofilm Development: A Structural Perspective

    PubMed Central

    Garnett, James A; Matthews, Steve

    2012-01-01

    A community-based life style is the normal mode of growth and survival for many bacterial species. These cellular accretions or biofilms are initiated upon recognition of solid phases by cell surface exposed adhesive moieties. Further cell-cell interactions, cell signalling and bacterial replication leads to the establishment of dense populations encapsulated in a mainly self-produced extracellular matrix; this comprises a complex mixture of macromolecules. These fascinating architectures protect the inhabitants from radiation damage, dehydration, pH fluctuations and antimicrobial compounds. As such they can cause bacterial persistence in disease and problems in industrial applications. In this review we discuss the current understandings of these initial biofilm-forming processes based on structural data. We also briefly describe latter biofilm maturation and dispersal events, which although lack high-resolution insights, are the present focus for many structural biologists working in this field. Finally we give an overview of modern techniques aimed at preventing and disrupting problem biofilms. PMID:23305361

  9. Solution structures of rat amylin peptide: simulation, theory, and experiment.

    PubMed

    Reddy, Allam S; Wang, Lu; Lin, Yu-Shan; Ling, Yun; Chopra, Manan; Zanni, Martin T; Skinner, James L; De Pablo, Juan J

    2010-02-03

    Amyloid deposits of amylin in the pancreas are an important characteristic feature found in patients with Type-2 diabetes. The aggregate has been considered important in the disease pathology and has been studied extensively. However, the secondary structures of the individual peptide have not been clearly identified. In this work, we present detailed solution structures of rat amylin using a combination of Monte Carlo and molecular dynamics simulations. A new Monte Carlo method is presented to determine the free energy of distinct biomolecular conformations. Both folded and random-coil conformations of rat amylin are observed in water and their relative stability is examined in detail. The former contains an alpha-helical segment comprised of residues 7-17. We find that at room temperature the folded structure is more stable, whereas at higher temperatures the random-coil structure predominates. From the configurations and weights we calculate the alpha-carbon NMR chemical shifts, with results that are in reasonable agreement with experiments of others. We also calculate the infrared spectrum in the amide I stretch regime, and the results are in fair agreement with the experimental line shape presented herein.

  10. Solution Structures of Rat Amylin Peptide: Simulation, Theory, and Experiment

    PubMed Central

    Reddy, Allam S.; Wang, Lu; Lin, Yu-Shan; Ling, Yun; Chopra, Manan; Zanni, Martin T.; Skinner, James L.; De Pablo, Juan J.

    2010-01-01

    Abstract Amyloid deposits of amylin in the pancreas are an important characteristic feature found in patients with Type-2 diabetes. The aggregate has been considered important in the disease pathology and has been studied extensively. However, the secondary structures of the individual peptide have not been clearly identified. In this work, we present detailed solution structures of rat amylin using a combination of Monte Carlo and molecular dynamics simulations. A new Monte Carlo method is presented to determine the free energy of distinct biomolecular conformations. Both folded and random-coil conformations of rat amylin are observed in water and their relative stability is examined in detail. The former contains an α-helical segment comprised of residues 7–17. We find that at room temperature the folded structure is more stable, whereas at higher temperatures the random-coil structure predominates. From the configurations and weights we calculate the α-carbon NMR chemical shifts, with results that are in reasonable agreement with experiments of others. We also calculate the infrared spectrum in the amide I stretch regime, and the results are in fair agreement with the experimental line shape presented herein. PMID:20141758

  11. Colloidal Disorder-Order Transition Experiment Probes Particle Interactions in Microgravity

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Everything in the universe is made up of the same basic building blocks - atoms. All physical properties of matter such as weight, hardness, and color are determined by the kind of atoms present and the way they interact with each other. The Colloidal Disorder-Order Transition (CDOT) shuttle flight experiment tested fundamental theories that model atomic interactions. The experiment was part of the Second United States Microgravity Laboratory (USML-2) aboard the Space Shuttle Columbia, which flew from October 20 to November 5, 1995.

  12. Fluid-structure interaction simulation of an avian flight model.

    PubMed

    Ruck, Sebastian; Oertel, Herbert

    2010-12-15

    A three-dimensional numerical avian model was developed to investigate the unsteady and turbulent aerodynamic performance of flapping wings for varying wingbeat frequencies and flow velocities (up to 12 Hz and 9 m s(-1)), corresponding to a reduced frequency range of k=0.22 to k=1.0 and a Reynolds number range of Re=16,000 to Re=50,000. The wings of the bird-inspired model consist of an elastic membrane. Simplifying the complicated locomotion kinematics to a sinusoidal wing rotation about two axes, the main features of dynamic avian flight were approximated. Numerical simulation techniques of fluid-structure interaction (FSI) providing a fully resolved flow field were applied to calculate the aerodynamic performance of the flapping elastic wings with the Reynolds averaged Navier-Stokes (RANS) approach. The results were used to characterize and describe the macroscopic flow configurations in terms of starting, stopping, trailing and bound vortices. For high reduced frequencies up to k=0.67 it was shown that the wake does not consist of individual vortex rings known as the discrete vortex ring gait. Rather, the wake is dominated by a chain of elliptical vortex rings on each wing. The structures are interlocked at the starting and stopping vortices, which are shed in pairs at the reversal points of the wingbeat cycle. For decreasing reduced frequency, the results indicate a transition to a continuous vortex gait. The upstroke becomes more aerodynamically active, leading to a consistent circulation of the bound vortex on the wing and a continuous spanwise shedding of small scale vortices. The formation of the vortices shed spanwise in pairs at the reversal points is reduced and the wake is dominated by the tip and root vortices, which form long drawn-out vortex structures.

  13. Embodied social interaction constitutes social cognition in pairs of humans: a minimalist virtual reality experiment.

    PubMed

    Froese, Tom; Iizuka, Hiroyuki; Ikegami, Takashi

    2014-01-14

    Scientists have traditionally limited the mechanisms of social cognition to one brain, but recent approaches claim that interaction also realizes cognitive work. Experiments under constrained virtual settings revealed that interaction dynamics implicitly guide social cognition. Here we show that embodied social interaction can be constitutive of agency detection and of experiencing another's presence. Pairs of participants moved their "avatars" along an invisible virtual line and could make haptic contact with three identical objects, two of which embodied the other's motions, but only one, the other's avatar, also embodied the other's contact sensor and thereby enabled responsive interaction. Co-regulated interactions were significantly correlated with identifications of the other's avatar and reports of the clearest awareness of the other's presence. These results challenge folk psychological notions about the boundaries of mind, but make sense from evolutionary and developmental perspectives: an extendible mind can offload cognitive work into its environment.

  14. Embodied social interaction constitutes social cognition in pairs of humans: A minimalist virtual reality experiment

    PubMed Central

    Froese, Tom; Iizuka, Hiroyuki; Ikegami, Takashi

    2014-01-01

    Scientists have traditionally limited the mechanisms of social cognition to one brain, but recent approaches claim that interaction also realizes cognitive work. Experiments under constrained virtual settings revealed that interaction dynamics implicitly guide social cognition. Here we show that embodied social interaction can be constitutive of agency detection and of experiencing another's presence. Pairs of participants moved their “avatars” along an invisible virtual line and could make haptic contact with three identical objects, two of which embodied the other's motions, but only one, the other's avatar, also embodied the other's contact sensor and thereby enabled responsive interaction. Co-regulated interactions were significantly correlated with identifications of the other's avatar and reports of the clearest awareness of the other's presence. These results challenge folk psychological notions about the boundaries of mind, but make sense from evolutionary and developmental perspectives: an extendible mind can offload cognitive work into its environment. PMID:24419102

  15. Deposition of diamond structures from interacting gas jets

    NASA Astrophysics Data System (ADS)

    Emel'yanov, A. A.; Rebrov, A. K.; Yudin, I. B.

    2016-12-01

    We have reported on the results of experiments on the gas-jet synthesis of diamond from methane and hydrogen flows for various mixing conditions. An original method of separate feed of gas jet has been proposed, which makes it possible to attain a high growth rate for the diamond phase. The synthesis of diamond structures in gas-jet deposition has been studied for separate feeds of two flows (hydrogen and the mixture of hydrogen with methane) in two versions, i.e., with a lateral feed of the methane-containing mixture and axisymmetric feed. Experiments were performed under the following conditions: the temperature of the surface (activating hydrogen) 2400 K, a substrate temperature of 900-1300 K, pressure in the deposition chamber 2 × 102 Pa, gas mixture fluxes (relative to hydrogen) 1500 ncm3/min, CH4 concentration in H2 of 0.1-0.7%, and the distance from the substrate to the reactor 10 mm. In the case of a separate feed of the methanecontaining gas and hydrogen, a deposition rate of 20 μm/h was attained. In the case of an axisymmetric separate feed of the gases, a single crystal with a mass of 0.6 mg was grown, which corresponded to the deposition rate of approximately 200 μm/h.

  16. Personal experience and reputation interact in human decisions to help reciprocally.

    PubMed

    Molleman, Lucas; van den Broek, Eva; Egas, Martijn

    2013-04-22

    There is ample evidence that human cooperative behaviour towards other individuals is often conditioned on information about previous interactions. This information derives both from personal experience (direct reciprocity) and from experience of others (i.e. reputation; indirect reciprocity). Direct and indirect reciprocity have been studied separately, but humans often have access to both types of information. Here, we experimentally investigate information use in a repeated helping game. When acting as donor, subjects can condition their decisions to help recipients with both types of information at a small cost to access such information. We find that information from direct interactions weighs more heavily in decisions to help, and participants tend to react less forgivingly to negative personal experience than to negative reputation. Moreover, effects of personal experience and reputation interact in decisions to help. If a recipient's reputation is positive, the personal experience of the donor has a weak effect on the decision to help, and vice versa. Yet if the two types of information indicate conflicting signatures of helpfulness, most decisions to help follow personal experience. To understand the roles of direct and indirect reciprocity in human cooperation, they should be studied in concert, not in isolation.

  17. Bioluminescence to reveal structure and interaction of coastal planktonic communities

    NASA Astrophysics Data System (ADS)

    Moline, Mark A.; Blackwell, Shelley M.; Case, James F.; Haddock, Steven H. D.; Herren, Christen M.; Orrico, Cristina M.; Terrill, Eric

    2009-02-01

    Ecosystem function will in large part be determined by functional groups present in biological communities. The simplest distinction with respect to functional groups of an ecosystem is the differentiation between primary and secondary producers. A challenge thus far has been to examine these groups simultaneously with sufficient temporal and spatial resolution for observations to be relevant to the scales of change in coastal oceans. This study takes advantage of general differences in the bioluminescence flash kinetics between planktonic dinoflagellates and zooplankton to measure relative abundances of the two groups within the same-time space volume. This novel approach for distinguishing these general classifications using a single sensor is validated using fluorescence data and exclusion experiments. The approach is then applied to data collected from an autonomous underwater vehicle surveying >500 km in Monterey Bay and San Luis Obispo Bay, CA during the summers of 2002-2004. The approach also reveals that identifying trophic interaction between the two planktonic communities may also be possible.

  18. Students' experiences with interactivity and learning in a high school physics multimedia distance learning course

    NASA Astrophysics Data System (ADS)

    Villarreal-Stewart, Irene

    The purpose guiding this research has been to learn about and describe the phenomena of interactivity from the learners' perspectives and to learn which of the interactivity affordances and practices were actually used by students and why in the process of learning physics using an interactive multimedia distance learning course system. The bigger purpose behind learning about and describing interactivity has been to gain knowledge and perspective for its instructional design to benefit the learner, the school as curriculum implementer, and instructional media designers to create better products. Qualitative methodology in the interpretivist tradition was used, that is, in-depth interviews and on-site observations, to gain understanding of interactivity from the learners' perspective and to gain understanding of the student learning context impacting and shaping the students' interactivity experiences. NVivo was used to sort, organize and index data. All data were read on three levels: literally, interpretively, and reflexively; and were read comparatively to other perspectives to get descriptions and interpretations that were holistic to the implementation and had potential insight to improve practice for instructional designers, teachers, administrators, specifically to improve the learning experience for students. Site-Specific Findings: Students watched videos, resisted using phone and e-mail, and worked math problems to demonstrate learning, which resulted in very little interactivity, virtually no dialogue about physics, no physical activity, one-way communication, multifaceted dissatisfaction, student need for teacher involvement in the learning enterprise, student appreciation for interactivity, and expressed desire for a real, live teacher. I also found that some students did experience the system as interactive, did experience learner control and self-directed learning, and despite dissatisfaction, liked and appreciated the course. Wider Applications

  19. Two-dimensional modeling of an aircraft engine structural bladed disk-casing modal interaction

    NASA Astrophysics Data System (ADS)

    Legrand, Mathias; Pierre, Christophe; Cartraud, Patrice; Lombard, Jean-Pierre

    2009-01-01

    In modern turbo machines such as aircraft jet engines, structural contacts between the casing and bladed disk may occur through a variety of mechanisms: coincidence of vibration modes, thermal deformation of the casing, rotor imbalance due to design uncertainties to name a few. These nonlinear interactions may result in severe damage to both structures and it is important to understand the physical circumstances under which they occur. In this study, we focus on a modal coincidence during which the vibrations of each structure take the form of a k-nodal diameter traveling wave characteristic of axi-symmetric geometries. A realistic two-dimensional model of the casing and bladed disk is introduced in order to predict the occurrence of this very specific interaction phenomenon versus the rotation speed of the engine. The equations of motion are solved using an explicit time integration scheme in conjunction with the Lagrange multiplier method where friction is accounted for. This model is validated from the comparison with an analytical solution. The numerical results show that the structures may experience different kinds of behaviors (namely damped, sustained and divergent motions) mainly depending on the rotational velocity of the bladed disk.

  20. DISCOS- DYNAMIC INTERACTION SIMULATION OF CONTROLS AND STRUCTURES (IBM VERSION)

    NASA Technical Reports Server (NTRS)

    Frisch, H. P.

    1994-01-01

    The Dynamic Interaction Simulation of Controls and Structure (DISCOS) program was developed for the dynamic simulation and stability analysis of passive and actively controlled spacecraft. In the use of DISCOS, the physical system undergoing analysis may be generally described as a cluster of contiguous flexible structures (bodies) that comprise a mechanical system, such as a spacecraft. The entire system (spacecraft) or portions thereof may be either spinning or nonspinning. Member bodies of the system may undergo large relative excursions, such as those of appendage deployment or rotor/ stator motion. The general system of bodies is, by its inherent nature, a feedback system in which inertial forces (such as those due to centrifugal and Coriolis acceleration) and the restoring and damping forces are motion-dependent. The system may possess a control system in which certain position and rate errors are actively controlled through the use of reaction control jets, servomotors, or momentum wheels. Bodies of the system may be interconnected by linear or nonlinear springs and dampers, by a gimbal and slider block mechanism, or by any combination of these. The DISCOS program can be used to obtain nonlinear and linearized time response of the system, interaction constant forces in the system, total system resonance properties, and frequency domain response and stability information for the system. DISCOS is probably the most powerful computational tool to date for the computer simulation of actively controlled coupled multi-flexible-body systems. The program is not easy to understand and effectively apply, but is not intended for simple problems. The DISCOS user is expected to have extensive working knowledge of rigid-body and flexible-body dynamics, finite-element techniques, numerical methods, and frequency-domain analysis. Various applications of DISCOS include simulation of the Shuttle payload deployment/retrieval mechanism, solar panel array deployment, antenna

  1. High School Students' Attitudes and Experiences in EFL Classrooms Equipped with Interactive Whiteboards

    ERIC Educational Resources Information Center

    Han, Turgay; Okatan, Semih

    2016-01-01

    The purpose of this study was to examine ninth grade EFL students' experiences and attitudes towards classrooms equipped with interactive whiteboards (IWB). The data were collected with a questionnaire about attitudes towards IWB use in EFL classes, and observations from three different classrooms in three different high schools. The study…

  2. How Do Interaction Experiences Influence Doctoral Students' Academic Pursuits in Biomedical Research?

    ERIC Educational Resources Information Center

    Kong, Xiaoqing; Chakraverty, Devasmita; Jeffe, Donna B.; Andriole, Dorothy A.; Wathington, Heather D.; Tai, Robert H.

    2013-01-01

    This exploratory qualitative study investigated how doctoral students reported their personal and professional interaction experiences that they believed might facilitate or impede their academic pursuits in biomedical research. We collected 19 in-depth interviews with doctoral students in biomedical research from eight universities, and we based…

  3. Enhancing Children's Language Learning and Cognition Experience through Interactive Kinetic Typography

    ERIC Educational Resources Information Center

    Lau, Newman M. L.; Chu, Veni H. T.

    2015-01-01

    This research aimed at investigating the method of using kinetic typography and interactive approach to conduct a design experiment for children to learn vocabularies. Typography is the unique art and technique of arranging type in order to make language visible. By adding animated movement to characters, kinetic typography expresses language…

  4. Effects of Professional Experience and Group Interaction on Information Requested in Analyzing IT Cases

    ERIC Educational Resources Information Center

    Lehmann, Constance M.; Heagy, Cynthia D.

    2008-01-01

    The authors investigated the effects of professional experience and group interaction on the information that information technology professionals and graduate accounting information system (AIS) students request when analyzing business cases related to information systems design and implementation. Understanding these effects can contribute to…

  5. Middle Years Science Teachers Voice Their First Experiences with Interactive Whiteboard Technology

    ERIC Educational Resources Information Center

    Gadbois, Shannon A.; Haverstock, Nicole

    2012-01-01

    Among new technologies, interactive whiteboards (IWBs) particularly seem to engage students and offer entertainment value that may make them highly beneficial for learning. This study examined 10 Grade 6 teachers' initial experiences and uses of IWBs for teaching science. Through interviews, classroom visits, and field notes, the outcomes…

  6. Towards Understanding the Two Way Interaction Effects of Extraversion and Openness to Experience on Career Commitment

    ERIC Educational Resources Information Center

    Arora, Ridhi; Rangnekar, Santosh

    2016-01-01

    In this study, we examined potential two-way interaction effects of the Big Five personality traits extraversion and openness to experience on career commitment measured in terms of three components of career identity, career resilience, and career planning. Participants included 450 managers from public and private sector organizations in North…

  7. On the Use of Interactive Texts in Undergraduate Chemical Reaction Engineering Courses: A Pedagogical Experience

    ERIC Educational Resources Information Center

    Asensio, Daniela A.; Barassi, Francisca J.; Zambon, Mariana T.; Mazza, Germán D.

    2010-01-01

    This paper describes the results of a pedagogical experience carried out at the University of Comahue, Argentina, with an interactive text (IT) concerning Homogeneous Chemical Reactors Analysis. The IT was built on the frame of the "Mathematica" software with the aim of providing students with a robust computational tool. Students'…

  8. User Experience of Mobile Interactivity: How Do Mobile Websites Affect Attitudes and Relational Outcomes?

    ERIC Educational Resources Information Center

    Dou, Xue

    2013-01-01

    Mobile media offer new opportunities for fostering communications between individuals and companies. Corporate websites are being increasingly accessed via smart phones and companies are scrambling to offer a mobile-friendly user experience on their sites. However, very little is known about how interactivity in the mobile context affects user…

  9. Reticent Behavior and Experiences in Peer Interactions in Chinese and Canadian Children

    ERIC Educational Resources Information Center

    Chen, Xinyin; DeSouza, Amanda T.; Chen, Huichang; Wang, Li

    2006-01-01

    In this study, the authors examined relations between reticent behavior in unfamiliar peer situations and experiences in interactions in Chinese and Canadian children. Observational data were collected from samples of children at 4 years of age in the People's Republic of China and Canada. The results indicated that relations between reticent…

  10. Plasma-wall interaction data needs critical to a Burning Core Experiment (BCX)

    SciTech Connect

    Not Available

    1985-11-01

    The Division of Development and Technology has sponsored a four day US-Japan workshop ''Plasma-Wall Interaction Data Needs Critical to a Burning Core Experiment (BCX)'', held at Sandia National Laboratories, Livermore, California on June 24 to 27, 1985. The workshop, which brought together fifty scientists and engineers from the United States, Japan, Germany, and Canada, considered the plasma-material interaction and high heat flux (PMI/HHF) issues for the next generation of magnetic fusion energy devices, the Burning Core Experiment (BCX). Materials options were ranked, and a strategy for future PMI/HHF research was formulated. The foundation for international collaboration and coordination of this research was also established. This volume contains the last three of the five technical sessions. The first of the three is on plasma materials interaction issues, the second is on research facilities and the third is from smaller working group meetings on graphite, beryllium, advanced materials and future collaborations.

  11. Observing the structure of the landscape with the CMB experiments

    SciTech Connect

    Ashoorioon, Amjad

    2010-04-01

    Assuming that inflation happened through a series of tunneling in the string theory landscape, it is argued that one can determine the structure of vacua using precise measurements of the scalar spectral index and tensor perturbations at large scales. It is shown that for a vacuum structure where the energy gap between the minima is constant, i.e. ε{sub i} = im{sub f}{sup 4}, one obtains the scalar spectral index, n{sub s}, to be ≅ 0.9687, for the modes that exit the horizon 60 e-folds before the end of inflation. Alternatively, for a vacuum structure in which the energy gap increases linearly with the vacuum index, i.e. ε{sub i} = ½i{sup 2}m{sub f}{sup 4}, n{sub s} turns out to be ≅ 0.9614. Both these two models are motivated within the string theory landscape using flux-compactification and their predictions for scalar spectral index are compatible with WMAP results. For both these two models, the results for the scalar spectral index turn out to be independent of m{sub f}. Nonetheless, assuming that inflation started at Planckian energies and that there had been successful thermalization at each step, one can constrain m{sub f} < 2.6069 × 10{sup −5}m{sub P} and m{sub f} < 6.5396 × 10{sup −7}m{sub P} in these two models, respectively. Violation of the single-field consistency relation between the tensor and scalar spectra is another prediction of chain inflation models. This corresponds to having a smaller tensor/scalar ratio at large scales in comparison with the slow-roll counterparts. Similar to slow-roll inflation, it is argued that one can reconstruct the vacuum structure using the CMB experiments.

  12. Assessing Spurious Interaction Effects in Structural Equation Modeling

    ERIC Educational Resources Information Center

    Harring, Jeffrey R.; Weiss, Brandi A.; Li, Ming

    2015-01-01

    Several studies have stressed the importance of simultaneously estimating interaction and quadratic effects in multiple regression analyses, even if theory only suggests an interaction effect should be present. Specifically, past studies suggested that failing to simultaneously include quadratic effects when testing for interaction effects could…

  13. Flow-structure-acoustic interaction in a human voice model.

    PubMed

    Becker, Stefan; Kniesburges, Stefan; Müller, Stefan; Delgado, Antonio; Link, Gerhard; Kaltenbacher, Manfred; Döllinger, Michael

    2009-03-01

    For the investigation of the physical processes of human phonation, inhomogeneous synthetic vocal folds were developed to represent the full fluid-structure-acoustic coupling. They consisted of polyurethane rubber with a stiffness in the range of human vocal folds and were mounted in a channel, shaped like the vocal tract in the supraglottal region. This test facility permitted extensive observations of flow-induced vocal fold vibrations, the periodic flow field, and the acoustic signals in the far field of the channel. Detailed measurements were performed applying particle-image velocimetry, a laser-scanning vibrometer, a microphone, unsteady pressure sensors, and a hot-wire probe, with the aim of identifying the physical mechanisms in human phonation. The results support the existence of the Coanda effect during phonation, with the flow attaching to one vocal fold and separating from the other. This behavior is not linked to one vocal fold and changes stochastically from cycle to cycle. The oscillating flow field generates a tonal sound. The broadband noise is presumed to be caused by the interaction of the asymmetric flow with the downstream-facing surfaces of the vocal folds, analogous to trailing-edge noise.

  14. Fluid-Structure interaction modeling in deformable porous arteries

    NASA Astrophysics Data System (ADS)

    Zakerzadeh, Rana; Zunino, Paolo

    2015-11-01

    A computational framework is developed to study the coupling of blood flow in arteries interacting with a poroelastic arterial wall featuring possibly large deformations. Blood is modeled as an incompressible, viscous, Newtonian fluid using the Navier-Stokes equations and the arterial wall consists of a thick material which is modeled as a Biot system that describes the mechanical behavior of a homogeneous and isotropic elastic skeleton, and connecting pores filled with fluid. Discretization via finite element method leads to the system of nonlinear equations and a Newton-Raphson scheme is adopted to solve the resulting nonlinear system through consistent linearization. Moreover, interface conditions are imposed on the discrete level via mortar finite elements or Nitsche's coupling. The discrete linearized coupled FSI system is solved by means of a splitting strategy, which allows solving the Navier-Stokes and Biot equations separately. The numerical results investigate the effects of proroelastic parameters on the pressure wave propagation in arteries, filtration of incompressible fluids through the porous media, and the structure displacement. The fellowship support from the Computational Modeling & Simulation PhD program at University of Pittsburgh for Rana Zakerzadeh is gratefully acknowledged.

  15. Structural features of DNA interaction with caffeine and theophylline

    NASA Astrophysics Data System (ADS)

    Nafisi, Shohreh; Manouchehri, Firouzeh; Tajmir-Riahi, Heidar-Ali; Varavipour, Maryam

    2008-03-01

    Caffeine and theophylline are strong antioxidants that prevent DNA damage. The anticancer and antiviral activities of these natural products are implicated in their mechanism of actions. However, there has been no information on the interactions of these xanthine derivatives with individual DNA at molecular level. The aim of this study was to examine the stability and structural features of calf-thymus DNA complexes with caffeine and theophylline in aqueous solution, using constant DNA concentration (6.25 mM) and various caffeine or theophylline/DNA(P) ratios of 1/80, 1/40, 1/20, 1/10, 1/5, 1/2 and 1/1. FTIR, UV-visible spectroscopic methods were used to determine the ligand external binding modes, the binding constant and the stability of caffeine, theophylline-DNA complexes in aqueous solution. Spectroscopic evidence showed that the complexation of caffeine and theophylline with DNA occurred via G-C and A-T and PO 2 group with overall binding constants of K(caffeine-DNA) = 9.7 × 10 3 M -1 and K(theophylline-DNA) = 1.7 × 10 4 M -1. The affinity of ligand-DNA binding is in the order of theophylline > caffeine. A partial B to A-DNA transition occurs upon caffeine and theophylline complexation.

  16. Bicuspid aortic valve hemodynamics: a fluid-structure interaction study

    NASA Astrophysics Data System (ADS)

    Chandra, Santanu; Seaman, Clara; Sucosky, Philippe

    2011-11-01

    The bicuspid aortic valve (BAV) is a congenital defect in which the aortic valve forms with two leaflets instead of three. While calcific aortic valve disease (CAVD) also develops in the normal tricuspid aortic valve (TAV), its progression in the BAV is more rapid. Although studies have suggested a mechano-potential root for the disease, the native BAV hemodynamics remains largely unknown. This study aimed at characterizing BAV hemodynamics and quantifying the degree of wall-shear stress (WSS) abnormality on BAV leaflets. Fluid-structure interaction models validated with particle-image velocimetry were designed to predict the flow and leaflet dynamics in idealized TAV and BAV anatomies. Valvular function was quantified in terms of the effective orifice area. The regional leaflet WSS was characterized in terms of oscillatory shear index, temporal shear magnitude and temporal shear gradient. The predictions indicate the intrinsic degree of stenosis of the BAV anatomy, reveal drastic differences in shear stress magnitude and pulsatility on BAV and TAV leaflets and confirm the side- and site-specificity of the leaflet WSS. Given the ability of abnormal fluid shear stress to trigger valvular inflammation, these results support the existence of a mechano-etiology of CAVD in the BAV.

  17. Numerical simulation of the fluid-structure interaction between air blast waves and soil structure

    NASA Astrophysics Data System (ADS)

    Umar, S.; Risby, M. S.; Albert, A. Luthfi; Norazman, M.; Ariffin, I.; Alias, Y. Muhamad

    2014-03-01

    Normally, an explosion threat on free field especially from high explosives is very dangerous due to the ground shocks generated that have high impulsive load. Nowadays, explosion threats do not only occur in the battlefield, but also in industries and urban areas. In industries such as oil and gas, explosion threats may occur on logistic transportation, maintenance, production, and distribution pipeline that are located underground to supply crude oil. Therefore, the appropriate blast resistances are a priority requirement that can be obtained through an assessment on the structural response, material strength and impact pattern of material due to ground shock. A highly impulsive load from ground shocks is a dynamic load due to its loading time which is faster than ground response time. Of late, almost all blast studies consider and analyze the ground shock in the fluid-structure interaction (FSI) because of its influence on the propagation and interaction of ground shock. Furthermore, analysis in the FSI integrates action of ground shock and reaction of ground on calculations of velocity, pressure and force. Therefore, this integration of the FSI has the capability to deliver the ground shock analysis on simulation to be closer to experimental investigation results. In this study, the FSI was implemented on AUTODYN computer code by using Euler-Godunov and the arbitrary Lagrangian-Eulerian (ALE). Euler-Godunov has the capability to deliver a structural computation on a 3D analysis, while ALE delivers an arbitrary calculation that is appropriate for a FSI analysis. In addition, ALE scheme delivers fine approach on little deformation analysis with an arbitrary motion, while the Euler-Godunov scheme delivers fine approach on a large deformation analysis. An integrated scheme based on Euler-Godunov and the arbitrary Lagrangian-Eulerian allows us to analyze the blast propagation waves and structural interaction simultaneously.

  18. Laser-plasma interaction in the context of inertial fusion: experiments and modeling

    NASA Astrophysics Data System (ADS)

    Labaune, C.; Lewis, K.; Bandulet, H.; Depierreux, S.; Hüller, S.; Masson-Laborde, P. E.; Pesme, D.; Loiseau, P.

    2007-08-01

    Many nonlinear processes may affect the laser beam propagation and the laser energy deposition in the underdense plasma surrounding the pellet. These processes, associated with anomalous and nonlinear absorption mechanisms, are fundamental issues in the context of Inertial Confinement Fusion. The work presented in this article refers to laser-plasma interaction experiments which were conducted under well-controlled conditions, and to their theoretical and numerical modeling. Thanks to important diagnostics improvements, the plasma and laser parameters were sufficiently characterized in these experiments to make it possible to carry out numerical simulations modeling the laser plasma interaction in which the hydrodynamics conditions were very close to the experimental ones. Two sets of experiments were carried out with the LULI 2000 and the six beam LULI laser facilities. In the first series of experiments, the interaction between two single hot spots was studied as a function of their distance, intensity and light polarization. In the second series, the intensity distribution of stimulated Brillouin scattering (SBS) inside the plasma was studied by means of a new temporally resolved imaging system. Two-dimensional (2D) simulations were carried out with our code Harmony2D in order to model these experiments. For both series of experiments, the numerical results show a very good agreement with the experimental ones for what concerns the main SBS features, namely the spatial and temporal behavior of the SBS-driven acoustic waves, as well as the average SBS reflectivities. Thus, these well diagnosed experiments, carried out with well defined conditions, make it possible to benchmark our theoretical and numerical modelings and, hence, to improve our predictive capabilities for future experiments.

  19. Complete structure of the bacterial flagellar hook reveals extensive set of stabilizing interactions

    PubMed Central

    Matsunami, Hideyuki; Barker, Clive S.; Yoon, Young-Ho; Wolf, Matthias; Samatey, Fadel A.

    2016-01-01

    The bacterial flagellar hook is a tubular helical structure made by the polymerization of multiple copies of a protein, FlgE. Here we report the structure of the hook from Campylobacter jejuni by cryo-electron microscopy at a resolution of 3.5 Å. On the basis of this structure, we show that the hook is stabilized by intricate inter-molecular interactions between FlgE molecules. Extra domains in FlgE, found only in Campylobacter and in related bacteria, bring more stability and robustness to the hook. Functional experiments suggest that Campylobacter requires an unusually strong hook to swim without its flagella being torn off. This structure reveals details of the quaternary organization of the hook that consists of 11 protofilaments. Previous study of the flagellar filament of Campylobacter by electron microscopy showed its quaternary structure made of seven protofilaments. Therefore, this study puts in evidence the difference between the quaternary structures of a bacterial filament and its hook. PMID:27811912

  20. The latent structure of the Peritraumatic Dissociative Experiences Questionnaire.

    PubMed

    Brooks, Robert; Bryant, Richard A; Silove, Derrick; Creamer, Mark; O'Donnell, Meaghan; McFarlane, Alexander C; Marmar, Charles R

    2009-04-01

    This paper has been retracted due to a publisher's error: the order of the authors was incorrect. The Editor and Publisher of the Journal of Traumatic Stress apologize to the authors and our readership. The Peritraumatic Dissociative Experiences Questionnaire (PDEQ) is a widely used measure of peritraumatic dissociation, and is presumably a unidimensional construct. Two hundred forty-seven individuals admitted to five hospitals after traumatic injury were administered the Clinician Administered PTSD Scale, the Hospital Anxiety and Depression Scale, and the PDEQ. Factor analysis indicated that the PDEQ involved two factors containing four items each: one factor (altered awareness) indexes alterations in awareness and the other (derealization) reflects distortions in perceptions of the self and the world. Only the derealization factor was associated with acute stress, anxiety, and depression symptoms. Cross-validation with independent data provided only partial support for the 2-factor structure model. These data indicate that peritraumatic dissociation may involve two distinct constructs.

  1. The influence of phase changes on debris-cloud interactions with protected structures

    SciTech Connect

    Lawrence, R.J.; Kmetyk, L.N.; Chhabildas, L.C.

    1994-05-16

    The physical state of the debris cloud generated by the interaction of a projectile with a thin target depends on the energy balance associated with above the sound speeds of the impact event. At impact velocities well materials involved, the cloud is expected to be primarily molten, but with some vapor present. A series of numerical calculations using the multi-dimensional finite-difference hydrocode CTH has been used to evaluate the effect of phase changes (i.e., different vapor fractions) on these clouds, and their subsequent interaction with backwall structures. In the calculations, higher concentrations of vapor are achieved by increasing the initial temperature of both the projectile and the thin shield while keeping the impact velocity constant, and by actually increasing the impact velocity. The nature of the debris cloud and its subsequent loading on the protected structure depend on both its thermal and physical state. This interaction can cause rupture, spallation or simply bulging of the backwall. These computational results are discussed and compared with new experimental observations obtained at an impact velocity of {approximately}10 km/s. In the experiment, the debris cloud was generated by the impact of a plate-shaped titanium projectile with a thin titanium shield.

  2. Structural, magnetic, and transport properties of Permalloy for spintronic experiments

    SciTech Connect

    Nahrwold, Gesche; Scholtyssek, Jan M.; Motl-Ziegler, Sandra; Albrecht, Ole; Merkt, Ulrich; Meier, Guido

    2010-07-15

    Permalloy (Ni{sub 80}Fe{sub 20}) is broadly used to prepare magnetic nanostructures for high-frequency experiments where the magnetization is either excited by electrical currents or magnetic fields. Detailed knowledge of the material properties is mandatory for thorough understanding its magnetization dynamics. In this work, thin Permalloy films are grown by dc-magnetron sputtering on heated substrates and by thermal evaporation with subsequent annealing. The specific resistance is determined by van der Pauw methods. Point-contact Andreev reflection is employed to determine the spin polarization of the films. The topography is imaged by atomic-force microscopy, and the magnetic microstructure by magnetic-force microscopy. Transmission-electron microscopy and transmission-electron diffraction are performed to determine atomic composition, crystal structure, and morphology. From ferromagnetic resonance absorption spectra the saturation magnetization, the anisotropy, and the Gilbert damping parameter are determined. Coercive fields and anisotropy are measured by magneto-optical Kerr magnetometry. The sum of the findings enables optimization of Permalloy for spintronic experiments.

  3. MEMS Reliability: Infrastructure, Test Structures, Experiments, and Failure Modes

    SciTech Connect

    TANNER,DANELLE M.; SMITH,NORMAN F.; IRWIN,LLOYD W.; EATON,WILLIAM P.; HELGESEN,KAREN SUE; CLEMENT,J. JOSEPH; MILLER,WILLIAM M.; MILLER,SAMUEL L.; DUGGER,MICHAEL T.; WALRAVEN,JEREMY A.; PETERSON,KENNETH A.

    2000-01-01

    The burgeoning new technology of Micro-Electro-Mechanical Systems (MEMS) shows great promise in the weapons arena. We can now conceive of micro-gyros, micro-surety systems, and micro-navigators that are extremely small and inexpensive. Do we want to use this new technology in critical applications such as nuclear weapons? This question drove us to understand the reliability and failure mechanisms of silicon surface-micromachined MEMS. Development of a testing infrastructure was a crucial step to perform reliability experiments on MEMS devices and will be reported here. In addition, reliability test structures have been designed and characterized. Many experiments were performed to investigate failure modes and specifically those in different environments (humidity, temperature, shock, vibration, and storage). A predictive reliability model for wear of rubbing surfaces in microengines was developed. The root causes of failure for operating and non-operating MEMS are discussed. The major failure mechanism for operating MEMS was wear of the polysilicon rubbing surfaces. Reliability design rules for future MEMS devices are established.

  4. Non-Chemical Distant Cellular Interactions as a potential confounder of cell biology experiments

    PubMed Central

    Farhadi, Ashkan

    2014-01-01

    Distant cells can communicate with each other through a variety of methods. Two such methods involve electrical and/or chemical mechanisms. Non-chemical, distant cellular interactions may be another method of communication that cells can use to modify the behavior of other cells that are mechanically separated. Moreover, non-chemical, distant cellular interactions may explain some cases of confounding effects in Cell Biology experiments. In this article, we review non-chemical, distant cellular interactions studies to try to shed light on the mechanisms in this highly unconventional field of cell biology. Despite the existence of several theories that try to explain the mechanism of non-chemical, distant cellular interactions, this phenomenon is still speculative. Among candidate mechanisms, electromagnetic waves appear to have the most experimental support. In this brief article, we try to answer a few key questions that may further clarify this mechanism. PMID:25368582

  5. Curvilinear Immersed Boundary Method for Simulating Fluid Structure Interaction with Complex 3D Rigid Bodies

    PubMed Central

    Borazjani, Iman; Ge, Liang; Sotiropoulos, Fotis

    2010-01-01

    The sharp-interface CURVIB approach of Ge and Sotiropoulos [L. Ge, F. Sotiropoulos, A Numerical Method for Solving the 3D Unsteady Incompressible Navier-Stokes Equations in Curvilinear Domains with Complex Immersed Boundaries, Journal of Computational Physics 225 (2007) 1782–1809] is extended to simulate fluid structure interaction (FSI) problems involving complex 3D rigid bodies undergoing large structural displacements. The FSI solver adopts the partitioned FSI solution approach and both loose and strong coupling strategies are implemented. The interfaces between immersed bodies and the fluid are discretized with a Lagrangian grid and tracked with an explicit front-tracking approach. An efficient ray-tracing algorithm is developed to quickly identify the relationship between the background grid and the moving bodies. Numerical experiments are carried out for two FSI problems: vortex induced vibration of elastically mounted cylinders and flow through a bileaflet mechanical heart valve at physiologic conditions. For both cases the computed results are in excellent agreement with benchmark simulations and experimental measurements. The numerical experiments suggest that both the properties of the structure (mass, geometry) and the local flow conditions can play an important role in determining the stability of the FSI algorithm. Under certain conditions unconditionally unstable iteration schemes result even when strong coupling FSI is employed. For such cases, however, combining the strong-coupling iteration with under-relaxation in conjunction with the Aitken’s acceleration technique is shown to effectively resolve the stability problems. A theoretical analysis is presented to explain the findings of the numerical experiments. It is shown that the ratio of the added mass to the mass of the structure as well as the sign of the local time rate of change of the force or moment imparted on the structure by the fluid determine the stability and convergence of the

  6. Structural Basis of the Allosteric Inhibitor Interaction on the HIV-1 Reverse Transcriptase RNase H domain

    PubMed Central

    Christen, Martin T.; Menon, Lakshmi; Myshakina, Nataliya A.; Ahn, Jinwoo; Parniak, Michael A.; Ishima, Rieko

    2012-01-01

    HIV-1 reverse transcriptase (RT) has been an attractive target for the development of antiretroviral agents. Although this enzyme is bi-functional, having both DNA polymerase and ribonuclease H (RNH) activities, there is no clinically approved inhibitor of the RNH activity. Here, we characterize the structural basis and molecular interaction of an allosteric site inhibitor, BHMP07, with the wild type (WT) RNH fragment. Solution NMR experiments for inhibitor titration on WT RNH showed relatively wide chemical shift perturbations, suggesting a long-range conformational effect on the inhibitor interaction. Comparisons of the inhibitor-induced NMR chemical-shift changes of RNH with those of RNH dimer, in the presence and absence of Mg2+, were performed to determine and verify the interaction site. The NMR results, with assistance of molecular docking, indicate that BHMP07 preferentially binds to a site that is located between the RNH active site and the region encompassing helices B and D (the “substrate-handle region”). The interaction site is consistent with the previous proposed site, identified using a chimeric RNH (p15-EC) [Gong, el (2011) Chem. Biol. Drug Des. 77, 39-47], but with slight differences that reflect the characteristics of the amino acid sequences in p15-EC compared to the WT RNH. PMID:22846652

  7. MOLECULAR INTERACTION POTENTIALS FOR THE DEVELOPMENT OF STRUCTURE-ACTIVITY RELATIONSHIPS

    EPA Science Inventory

    Abstract
    One reasonable approach to the analysis of the relationships between molecular structure and toxic activity is through the investigation of the forces and intermolecular interactions responsible for chemical toxicity. The interaction between the xenobiotic and the bio...

  8. FRETsg: Biomolecular structure model building from multiple FRET experiments

    NASA Astrophysics Data System (ADS)

    Schröder, G. F.; Grubmüller, H.

    2004-04-01

    Fluorescence energy transfer (FRET) experiments of site-specifically labelled proteins allow one to determine distances between residues at the single molecule level, which provide information on the three-dimensional structural dynamics of the biomolecule. To systematically extract this information from the experimental data, we describe a program that generates an ensemble of configurations of residues in space that agree with the experimental distances between these positions. Furthermore, a fluctuation analysis allows to determine the structural accuracy from the experimental error. Program summaryTitle of program: FRETsg Catalogue identifier: ADTU Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTU Computer: SGI Octane, Pentium II/III, Athlon MP, DEC Alpha Operating system: Unix, Linux, Windows98/NT/XP Programming language used: ANSI C No. of bits in a word: 32 or 64 No. of processors used: 1 No. of bytes in distributed program, including test data, etc.: 11407 No. of lines in distributed program, including test data, etc.: 1647 Distribution format: gzipped tar file Nature of the physical problem: Given an arbitrary number of distance distributions between an arbitrary number of points in three-dimensional space, find all configurations (set of coordinates) that obey the given distances. Method of solution: Each distance is described by a harmonic potential. Starting from random initial configurations, their total energy is minimized by steepest descent. Fluctuations of positions are chosen to generate distance distribution widths that best fit the given values.

  9. How can a recurrent neurodynamic predictive coding model cope with fluctuation in temporal patterns? Robotic experiments on imitative interaction.

    PubMed

    Ahmadi, Ahmadreza; Tani, Jun

    2017-03-21

    The current paper examines how a recurrent neural network (RNN) model using a dynamic predictive coding scheme can cope with fluctuations in temporal patterns through generalization in learning. The conjecture driving this present inquiry is that a RNN model with multiple timescales (MTRNN) learns by extracting patterns of change from observed temporal patterns, developing an internal dynamic structure such that variance in initial internal states account for modulations in corresponding observed patterns. We trained a MTRNN with low-dimensional temporal patterns, and assessed performance on an imitation task employing these patterns. Analysis reveals that imitating fluctuated patterns consists in inferring optimal internal states by error regression. The model was then tested through humanoid robotic experiments requiring imitative interaction with human subjects. Results show that spontaneous and lively interaction can be achieved as the model successfully copes with fluctuations naturally occurring in human movement patterns.

  10. Multiple supramolecular structures formed by interaction of actin with protamine

    PubMed Central

    Grazi, Enrico; Magri, Ermes; Pasquali-Ronchetti, Ivonne

    1982-01-01

    When protamine is added to actin, different supramolecular structures are formed depending on the molar ratio of the two proteins and of the ionic strength of the medium. At low ionic strength, and going from a molar ratio of protamine to G-actin of 4:1, 2:1 and 1:1, globular aggregates are first converted into extended structures and then to long threads in which the constituent ATP–G-actin is rapidly exchangeable with the actin of the medium. At high ionic strength {Tyrode [(1910) Arch. Int. Pharmacodyn. Ther. 20, 205–212] solution}, starting from G-actin and protamine in the 1:1 molar ratio, long ropes are formed that can be resolved into intertwining filaments of 4–5nm diameter. The addition of protamine in a 1:1 molar ratio to a solution of F-actin in Tyrode solution causes the breakage of the actin filaments, which is also revealed by the decrease of the viscosity of the solution and the formation of ordered latero-lateral aggregates. The structures formed by reaction of protamine with G-actin can be separated from free G-actin and protamine by filtration through 0.45μm-pore-size Millipore filters. This technique has been exploited to study the exchange reaction between free actin and the actin–protamine complexes. For these studies the 1:1 actin–protamine complex formed at low ionic strength and the 2:1 actin–protamine complex formed in the presence of 23nm-free Mg2+ have been selected. In the first case the exchange reaction is practically complete in the dead time of the experiment (20s). In the second case, where the complex operates like a true ATPase, the rate of the exchange is initially comparable with the rate of the ATP cleavage. Later on, however, the complex undergoes a change and the rate of the exchange between free actin and the actin bound to protamine becomes lower than the rate of the ATPase reaction. It is proposed that the ATP exchanges for ADP directly on the G-actin bound in the complex. ImagesPLATE 1PLATE 2PLATE 3 PMID

  11. Trophic and Non-Trophic Interactions in a Biodiversity Experiment Assessed by Next-Generation Sequencing

    PubMed Central

    Tiede, Julia; Wemheuer, Bernd; Traugott, Michael; Daniel, Rolf; Tscharntke, Teja; Ebeling, Anne; Scherber, Christoph

    2016-01-01

    Plant diversity affects species richness and abundance of taxa at higher trophic levels. However, plant diversity effects on omnivores (feeding on multiple trophic levels) and their trophic and non-trophic interactions are not yet studied because appropriate methods were lacking. A promising approach is the DNA-based analysis of gut contents using next generation sequencing (NGS) technologies. Here, we integrate NGS-based analysis into the framework of a biodiversity experiment where plant taxonomic and functional diversity were manipulated to directly assess environmental interactions involving the omnivorous ground beetle Pterostichus melanarius. Beetle regurgitates were used for NGS-based analysis with universal 18S rDNA primers for eukaryotes. We detected a wide range of taxa with the NGS approach in regurgitates, including organisms representing trophic, phoretic, parasitic, and neutral interactions with P. melanarius. Our findings suggest that the frequency of (i) trophic interactions increased with plant diversity and vegetation cover; (ii) intraguild predation increased with vegetation cover, and (iii) neutral interactions with organisms such as fungi and protists increased with vegetation cover. Experimentally manipulated plant diversity likely affects multitrophic interactions involving omnivorous consumers. Our study therefore shows that trophic and non-trophic interactions can be assessed via NGS to address fundamental questions in biodiversity research. PMID:26859146

  12. Extended ALE Method for fluid-structure interaction problems with large structural displacements

    NASA Astrophysics Data System (ADS)

    Basting, Steffen; Quaini, Annalisa; Čanić, Sunčica; Glowinski, Roland

    2017-02-01

    Standard Arbitrary Lagrangian-Eulerian (ALE) methods for the simulation of fluid-structure interaction (FSI) problems fail due to excessive mesh deformations when the structural displacement is large. We propose a method that successfully deals with this problem, keeping the same mesh connectivity while enforcing mesh alignment with the structure. The proposed Extended ALE Method relies on a variational mesh optimization technique, where mesh alignment with the structure is achieved via a constraint. This gives rise to a constrained optimization problem for mesh optimization, which is solved whenever the mesh quality deteriorates. The performance of the proposed Extended ALE Method is demonstrated on a series of numerical examples involving 2D FSI problems with large displacements. Two-way coupling between the fluid and structure is considered in all the examples. The FSI problems are solved using either a Dirichlet-Neumann algorithm, or a Robin-Neumann algorithm. The Dirichlet-Neumann algorithm is enhanced by an adaptive relaxation procedure based on Aitken's acceleration. We show that the proposed method has excellent performance in problems with large displacements, and that it agrees well with a standard ALE method in problems with mild displacement.

  13. Experiments on laser-produced plasmas and laser plasma- wall interactions

    NASA Astrophysics Data System (ADS)

    Wang, Quan

    2001-06-01

    The study of the interaction of laser-produced plasmas with a secondary wall has both practical and theoretical significance. The laser-produced plasmas are sources of highly-charged ions, fast electrons, as well as continuum and monochromatic x-ray radiation. Intense x-ray radiation also results when a nanosecond laser-produced plasma collides with a secondary wall positioned close to the target. The study of this interaction is essential to understand the laser-produced plasma expansion, shock wave formation, recombination, collisional excitation and many other transition processes. The laser plasma-wall interaction experiment has been carried out with laser pulses with vastly different time scales. In nanosecond experiment, the plasma-wall interaction was studied with varying target-wall distance. We conclude that the isothermal plasma expansion followed by the shock wave formation near the wall surface contributes to the intense x-ray radiation. We also have done some preliminary research in the femtosecond regime. We claim that the shock wave formation that plays an important role in nanosecond experiment does not play the same role in femtosecond one. We suggest that a femtosecond laser-produced plasma could be an efficient fast electron and monochromatic x- ray source. We also provide some suggestions and predictions for further investigations.

  14. A new multimodal interactive way of subjective scoring of 3D video quality of experience

    NASA Astrophysics Data System (ADS)

    Kim, Taewan; Lee, Kwanghyun; Lee, Sanghoon; Bovik, Alan C.

    2014-03-01

    People that watch today's 3D visual programs, such as 3D cinema, 3D TV and 3D games, experience wide and dynamically varying ranges of 3D visual immersion and 3D quality of experience (QoE). It is necessary to be able to deploy reliable methodologies that measure each viewers subjective experience. We propose a new methodology that we call Multimodal Interactive Continuous Scoring of Quality (MICSQ). MICSQ is composed of a device interaction process between the 3D display and a separate device (PC, tablet, etc.) used as an assessment tool, and a human interaction process between the subject(s) and the device. The scoring process is multimodal, using aural and tactile cues to help engage and focus the subject(s) on their tasks. Moreover, the wireless device interaction process makes it possible for multiple subjects to assess 3D QoE simultaneously in a large space such as a movie theater, and at di®erent visual angles and distances.

  15. Three Dimensional Viscous Finite Element Formulation For Acoustic Fluid Structure Interaction

    PubMed Central

    Cheng, Lei; White, Robert D.; Grosh, Karl

    2010-01-01

    A three dimensional viscous finite element model is presented in this paper for the analysis of the acoustic fluid structure interaction systems including, but not limited to, the cochlear-based transducers. The model consists of a three dimensional viscous acoustic fluid medium interacting with a two dimensional flat structure domain. The fluid field is governed by the linearized Navier-Stokes equation with the fluid displacements and the pressure chosen as independent variables. The mixed displacement/pressure based formulation is used in the fluid field in order to alleviate the locking in the nearly incompressible fluid. The structure is modeled as a Mindlin plate with or without residual stress. The Hinton-Huang’s 9-noded Lagrangian plate element is chosen in order to be compatible with 27/4 u/p fluid elements. The results from the full 3d FEM model are in good agreement with experimental results and other FEM results including Beltman’s thin film viscoacoustic element [2] and two and half dimensional inviscid elements [21]. Although it is computationally expensive, it provides a benchmark solution for other numerical models or approximations to compare to besides experiments and it is capable of modeling any irregular geometries and material properties while other numerical models may not be applicable. PMID:20174602

  16. Bridging experiment and theory: A template for unifying NMR data and electronic structure calculations

    SciTech Connect

    Brown, David M. L.; Cho, Herman; de Jong, Wibe A.

    2016-02-09

    Here, the testing of theoretical models with experimental data is an integral part of the scientific method, and a logical place to search for new ways of stimulating scientific productivity. Often experiment/theory comparisons may be viewed as a workflow comprised of well-defined, rote operations distributed over several distinct computers, as exemplified by the way in which predictions from electronic structure theories are evaluated with results from spectroscopic experiments. For workflows such as this, which may be laborious and time consuming to perform manually, software that could orchestrate the operations and transfer results between computers in a seamless and automated fashion would offer major efficiency gains. Such tools also promise to alter how researchers interact with data outside their field of specialization by, e.g., making raw experimental results more accessible to theorists, and the outputs of theoretical calculations more readily comprehended by experimentalists.

  17. Bridging experiment and theory: A template for unifying NMR data and electronic structure calculations

    DOE PAGES

    Brown, David M. L.; Cho, Herman; de Jong, Wibe A.

    2016-02-09

    Here, the testing of theoretical models with experimental data is an integral part of the scientific method, and a logical place to search for new ways of stimulating scientific productivity. Often experiment/theory comparisons may be viewed as a workflow comprised of well-defined, rote operations distributed over several distinct computers, as exemplified by the way in which predictions from electronic structure theories are evaluated with results from spectroscopic experiments. For workflows such as this, which may be laborious and time consuming to perform manually, software that could orchestrate the operations and transfer results between computers in a seamless and automated fashionmore » would offer major efficiency gains. Such tools also promise to alter how researchers interact with data outside their field of specialization by, e.g., making raw experimental results more accessible to theorists, and the outputs of theoretical calculations more readily comprehended by experimentalists.« less

  18. Structure-templated predictions of novel protein interactions from sequence information.

    PubMed

    Betel, Doron; Breitkreuz, Kevin E; Isserlin, Ruth; Dewar-Darch, Danielle; Tyers, Mike; Hogue, Christopher W V

    2007-09-01

    The multitude of functions performed in the cell are largely controlled by a set of carefully orchestrated protein interactions often facilitated by specific binding of conserved domains in the interacting proteins. Interacting domains commonly exhibit distinct binding specificity to short and conserved recognition peptides called binding profiles. Although many conserved domains are known in nature, only a few have well-characterized binding profiles. Here, we describe a novel predictive method known as domain-motif interactions from structural topology (D-MIST) for elucidating the binding profiles of interacting domains. A set of domains and their corresponding binding profiles were derived from extant protein structures and protein interaction data and then used to predict novel protein interactions in yeast. A number of the predicted interactions were verified experimentally, including new interactions of the mitotic exit network, RNA polymerases, nucleotide metabolism enzymes, and the chaperone complex. These results demonstrate that new protein interactions can be predicted exclusively from sequence information.

  19. Tango and enactivism: first steps in exploring the dynamics and experience of interaction.

    PubMed

    van Alphen, Floor

    2014-09-01

    Tango dancing is not just ethnographically interesting, but might actually provide a way to study interaction as such. An orientation to this improvisational dance as an embodied practice and experience is given. Enactivism is proposed as an adequate framework for further study. It is argued that approaching tango in terms of participatory sense-making, mutual incorporation and consensually coordinated action helps in clarifying its possible contributions to (cultural) psychology. Possible contributions such as facilitating the study of the dynamics of interaction, of intersubjectivity and of culture as joint activity.

  20. Long-term experiments to better understand soil-human interactions

    NASA Astrophysics Data System (ADS)

    Bormann, B. T.; Homann, P. S.

    2011-12-01

    Interactions between soils and people may be transforming global conditions, but the interactions are poorly understood. Changes in soils have proven difficult to quantify, especially in complex ecosystems manifesting large spatiotemporal variability. Long-term ecosystem experiments that evaluate soil change and demonstrate alternative choices are important to understanding changes, discovering new controls and drivers, and influencing decisions. Inspired by agriculture studies, like Rothamsted, the US Forest Service established in 1990 a network of operational-scale experiments across the Pacific Northwest to evaluate long-term effects of different forest management and disturbance regimes. With a strong experimental design, these experiments are now helping to better understand the long-term effects of managing tree harvesting (clearcutting and thinning), woody debris, and tree and understory species composition, and-serendipitously-the effects of fire. Initial results from the Southern Oregon experimental site indicate surprisingly rapid soil changes in some regimes but not others. We've also learned that rapid change presents challenges to repeat sampling. We present our sample-archive and comparable-layer approaches that seek to accommodate changes in surface elevation, aggregation and disaggregation, and mineral-soil exports. Thinning mature forest stands (80-100 yrs old) did not significantly change soil C in 11-yrs. A small upper-layer C increase was observed after thinning, but it was similar to the control. Significant increases in upper-layer soil N were observed with most treatments, but all increases were similar to the control. Leaving woody debris had little effect. The most remarkable change occurred when mature stands were clearcut and Douglas-firs were planted and tended. Associated with rapid growth of Douglas-fir, an average of 8 Mg C ha-1 was lost from weathered soil 4-18 cm deep. This contrasts with clearcuts where early-seral hardwoods and

  1. PHENIX (Pioneering High Energy Nuclear Interaction eXperiment): Data Tables and Figures from Published Papers

    DOE Data Explorer

    The PHENIX Experiment is the largest of the four experiments currently taking data at the Relativistic Heavy Ion Collider. PHENIX, the Pioneering High Energy Nuclear Interaction eXperiment, is an exploratory experiment for the investigation of high energy collisions of heavy ions and protons. PHENIX is designed specifically to measure direct probes of the collisions such as electrons, muons, and photons. The primary goal of PHENIX is to discover and study a new state of matter called the Quark-Gluon Plasma. More than 60 published papers and preprints are listed here with links to the full text and separate links to the supporting PHENIX data in plain text tables and to EPS and GIF figures from the papers.

  2. PHENIX (Pioneering High Energy Nuclear Interaction eXperiment) Data Plots from the PHENIX Plot Database

    DOE Data Explorer

    The PHENIX Experiment is the largest of the four experiments currently taking data at the Relativistic Heavy Ion Collider. PHENIX, the Pioneering High Energy Nuclear Interaction eXperiment, is an exploratory experiment for the investigation of high energy collisions of heavy ions and protons. PHENIX is designed specifically to measure direct probes of the collisions such as electrons, muons, and photons.The primary goal of PHENIX is to discover and study a new state of matter called the Quark-Gluon Plasma.[From http://www.phenix.bnl.gov/phenix/WWW/intro/] The PHENIX plot database allows searching by collision species, energies of the X and Y axis, and specific runs. Figures and data plots from published PHENIX papers are also available at http://www.phenix.bnl.gov//WWW/talk/pub_papers.php. (Specialized Interface)

  3. Learning about Intermolecular Interactions from the Cambridge Structural Database

    ERIC Educational Resources Information Center

    Battle, Gary M.; Allen, Frank H.

    2012-01-01

    A clear understanding and appreciation of noncovalent interactions, especially hydrogen bonding, are vitally important to students of chemistry and the life sciences, including biochemistry, molecular biology, pharmacology, and medicine. The opportunities afforded by the IsoStar knowledge base of intermolecular interactions to enhance the…

  4. Phytoplankton community structure in the VAHINE mesocosm experiment

    NASA Astrophysics Data System (ADS)

    Leblanc, Karine; Cornet, Véronique; Caffin, Mathieu; Rodier, Martine; Desnues, Anne; Berthelot, Hugo; Turk-Kubo, Kendra; Heliou, Jules

    2016-09-01

    The VAHINE mesocosm experiment was designed to trigger a diazotroph bloom and to follow the subsequent transfer of diazotroph-derived nitrogen (DDN) in the rest of the food web. Three mesocosms (50 m3) located inside the Nouméa lagoon (New Caledonia, southwestern Pacific) were enriched with dissolved inorganic phosphorus (DIP) in order to promote N2 fixation in these low-nutrient, low-chlorophyll (LNLC) waters. Initially, the diazotrophic community was dominated by diatom diazotroph associations (DDAs), mainly by Rhizosolenia/Richelia intracellularis, and by Trichodesmium, which fueled enough DDN to sustain the growth of other diverse diatom species and Synechococcus populations that were well adapted to limiting DIP levels. After DIP fertilization (1 µM) on day 4, an initial lag time of 10 days was necessary for the mesocosm ecosystems to start building up biomass. However, changes in community structure were already observed during this first period, with a significant drop of both Synechococcus and diatom populations, while Prochlorococcus benefited from DIP addition. At the end of this first period, corresponding to when most added DIP was consumed, the diazotroph community changed drastically and became dominated by Cyanothece-like (UCYN-C) populations, which were accompanied by a monospecific bloom of the diatom Cylindrotheca closterium. During the second period, biomass increased sharply together with primary production and N2-fixation fluxes near tripled. Diatom populations, as well as Synechococcus and nanophytoeukaryotes, showed a re-increase towards the end of the experiment, showing efficient transfer of DDN to non-diazotrophic phytoplankton.

  5. Simplified analysis of frame structures with viscoelastic dampers considering the effect of soil-structure interaction

    NASA Astrophysics Data System (ADS)

    Zhao, Xuefei; Wang, Shuguang; Du, Dongsheng; Liu, Weiqing

    2017-01-01

    In this study, simplified numerical models are developed to analyze the soil-structure interaction (SSI) effect on frame structures equipped with viscoelastic dampers (VEDs) based on pile group foundation. First, a single degree-of-freedom (SDOF) oscillator is successfully utilized to replace the SDOF energy dissipated structure considering the SSI effect. The equivalent period and damping ratio of the system are obtained through analogical analysis using the frequency transfer function with adoption of the modal strain energy (MSE) technique. A parametric analysis is carried out to study the SSI effect on the performance of VEDs. Then the equilibrium equations of the multi degree-of-freedom (MDOF) structure with VEDs considering SSI effect are established in the frequency domain. Based on the assumption that the superstructure of the coupled system possesses the classical normal mode, the MDOF superstructure is decoupled to a set of individual SDOF systems resting on a rigid foundation with adoption of the MSE technique through formula derivation. Numerical results demonstrate that the proposed methods have the advantage of reducing computational cost, however, retaining the satisfactory accuracy. The numerical method proposed herein can provide a fast evaluation of the efficiency of VEDs considering the SSI effect.

  6. Fluid-structure interaction in abdominal aortic aneurysms: Structural and geometrical considerations

    NASA Astrophysics Data System (ADS)

    Mesri, Yaser; Niazmand, Hamid; Deyranlou, Amin; Sadeghi, Mahmood Reza

    2015-08-01

    Rupture of the abdominal aortic aneurysm (AAA) is the result of the relatively complex interaction of blood hemodynamics and material behavior of arterial walls. In the present study, the cumulative effects of physiological parameters such as the directional growth, arterial wall properties (isotropy and anisotropy), iliac bifurcation and arterial wall thickness on prediction of wall stress in fully coupled fluid-structure interaction (FSI) analysis of five idealized AAA models have been investigated. In particular, the numerical model considers the heterogeneity of arterial wall and the iliac bifurcation, which allows the study of the geometric asymmetry due to the growth of the aneurysm into different directions. Results demonstrate that the blood pulsatile nature is responsible for emerging a time-dependent recirculation zone inside the aneurysm, which directly affects the stress distribution in aneurismal wall. Therefore, aneurysm deviation from the arterial axis, especially, in the lateral direction increases the wall stress in a relatively nonlinear fashion. Among the models analyzed in this investigation, the anisotropic material model that considers the wall thickness variations, greatly affects the wall stress values, while the stress distributions are less affected as compared to the uniform wall thickness models. In this regard, it is confirmed that wall stress predictions are more influenced by the appropriate structural model than the geometrical considerations such as the level of asymmetry and its curvature, growth direction and its extent.

  7. Alignment editing and identification of consensus secondary structures for nucleic acid sequences: interactive use of dot matrix representations.

    PubMed Central

    Davis, J P; Janjić, N; Pribnow, D; Zichi, D A

    1995-01-01

    We present a computer-aided approach for identifying and aligning consensus secondary structure within a set of functionally related oligonucleotide sequences aligned by sequence. The method relies on visualization of secondary structure using a generalization of the dot matrix representation appropriate for consensus sequence data sets. An interactive computer program implementing such a visualization of consensus structure has been developed. The program allows for alignment editing, data and display filtering and various modes of base pair representation, including co-variation. The utility of this approach is demonstrated with four sample data sets derived from in vitro selection experiments and one data set comprising tRNA sequences. Images PMID:7501472

  8. Structure Modeling and Validation applied to Source Physics Experiments (SPEs)

    NASA Astrophysics Data System (ADS)

    Larmat, C. S.; Rowe, C. A.; Patton, H. J.

    2012-12-01

    The U. S. Department of Energy's Source Physics Experiments (SPEs) comprise a series of small chemical explosions used to develop a better understanding of seismic energy generation and wave propagation for low-yield explosions. In particular, we anticipate improved understanding of the processes through which shear waves are generated by the explosion source. Three tests, 100, 1000 and 1000 kg yields respectively, were detonated in the same emplacement hole and recorded on the same networks of ground motion sensors in the granites of Climax Stock at the Nevada National Security Site. We present results for the analysis and modeling of seismic waveforms recorded close-in on five linear geophone lines extending radially from ground zero, having offsets from 100 to 2000 m and station spacing of 100 m. These records exhibit azimuthal variations of P-wave arrival times, and phase velocity, spreading and attenuation properties of high-frequency Rg waves. We construct a 1D seismic body-wave model starting from a refraction analysis of P-waves and adjusting to address time-domain and frequency-domain dispersion measurements of Rg waves between 2 and 9 Hz. The shallowest part of the structure we address using the arrival times recorded by near-field accelerometers residing within 200 m of the shot hole. We additionally perform a 2D modeling study with the Spectral Element Method (SEM) to investigate which structural features are most responsible for the observed variations, in particular anomalously weak amplitude decay in some directions of this topographically complicated locality. We find that a near-surface, thin, weathered layer of varying thickness and low wave speeds plays a major role on the observed waveforms. We anticipate performing full 3D modeling of the seismic near-field through analysis and validation of waveforms on the 5 radial receiver arrays.

  9. Velocity evolution of electro-magnetically driven shock wave for beam-dissociated hydrogen interaction experiment

    NASA Astrophysics Data System (ADS)

    Kondo, Kotaro; Oguri, Yoshiyuki

    2016-03-01

    We present the velocity measurements in electro-magnetic shock tube for beam interaction experiment by three methods; laser refraction, photodiode for self-emission, and high speed framing camera. The laser refraction showed that the average shock velocity was 6.7 km/s when the initial pressure was 1000 Pa and the initial charging voltage was 16 kV. The self-emissions from piston discharge plasma were measured by photodiodes and by high speed framing camera. The measurements showed that the duration between shock and piston was up to 8 microseconds with a 400-mm propagation in the shock tube, which is enough time as dissociation target for beam interaction experiment.The complementary velocity measurement is significant for understanding the electro-magnetically driven shock physics.

  10. Interactive Web-based Learning Modules Prior to General Medicine Advanced Pharmacy Practice Experiences

    PubMed Central

    Walton, Alison M.; Nisly, Sarah A.

    2015-01-01

    Objective. To implement and evaluate interactive web-based learning modules prior to advanced pharmacy practice experiences (APPEs) on inpatient general medicine. Design. Three clinical web-based learning modules were developed for use prior to APPEs in 4 health care systems. The aim of the interactive modules was to strengthen baseline clinical knowledge before the APPE to enable the application of learned material through the delivery of patient care. Assessment. For the primary endpoint, postassessment scores increased overall and for each individual module compared to preassessment scores. Postassessment scores were similar among the health care systems. The survey demonstrated positive student perceptions of this learning experience. Conclusion. Prior to inpatient general medicine APPEs, web-based learning enabled the standardization and assessment of baseline student knowledge across 4 health care systems. PMID:25995515

  11. Conditioned activity and the interaction of amphetamine experience with morphine's activity effects.

    PubMed

    Krank, M D; Bennett, D

    1987-11-01

    This experiment assessed the transfer effect of Pavlovian conditioning with d-amphetamine sulfate (1 mg/kg) on morphine's activity effects. Prior experience with amphetamine resulted in higher levels of activity when challenged with morphine (10 and 20 mg/kg). This interactive effect of amphetamine, however, was present only in those animals who had experienced amphetamine paired with the activity test situation. Animals who had received equivalent doses of amphetamine unpaired with the testing environment did not differ from drug-naive control animals. Analysis of predrug activity levels revealed a conditioned activity response in paired animals compared to the controls. These findings suggest that the response interaction between drug conditioned responses and drug unconditioned responses is an important determinant of cross-drug effects between drugs of different pharmacological classes.

  12. Experimenting with ecosystem interaction networks in search of threshold potentials in real-world marine ecosystems.

    PubMed

    Thrush, Simon F; Hewitt, Judi E; Parkes, Samantha; Lohrer, Andrew M; Pilditch, Conrad; Woodin, Sarah A; Wethey, David S; Chiantore, Mariachiara; Asnaghi, Valentina; De Juan, Silvia; Kraan, Casper; Rodil, Ivan; Savage, Candida; Van Colen, Carl

    2014-06-01

    Thresholds profoundly affect our understanding and management of ecosystem dynamics, but we have yet to develop practical techniques to assess the risk that thresholds will be crossed. Combining ecological knowledge of critical system interdependencies with a large-scale experiment, we tested for breaks in the ecosystem interaction network to identify threshold potential in real-world ecosystem dynamics. Our experiment with the bivalves Macomona liliana and Austrovenus stutchburyi on marine sandflats in New Zealand demonstrated that reductions in incident sunlight changed the interaction network between sediment biogeochemical fluxes, productivity, and macrofauna. By demonstrating loss of positive feedbacks and changes in the architecture of the network, we provide mechanistic evidence that stressors lead to break points in dynamics, which theory predicts predispose a system to a critical transition.

  13. Intra- and inter-nucleosome interactions of the core histone tail domains in higher-order chromatin structure.

    PubMed

    Pepenella, Sharon; Murphy, Kevin J; Hayes, Jeffrey J

    2014-03-01

    Eukaryotic chromatin is a hierarchical collection of nucleoprotein structures that package DNA to form chromosomes. The initial levels of packaging include folding of long strings of nucleosomes into secondary structures and array-array association into higher-order tertiary chromatin structures. The core histone tail domains are required for the assembly of higher-order structures and mediate short- and long-range intra- and inter-nucleosome interactions with both DNA and protein targets to direct their assembly. However, important details of these interactions remain unclear and are a subject of much interest and recent investigations. Here, we review work defining the interactions of the histone N-terminal tails with DNA and protein targets relevant to chromatin higher-order structures, with a specific emphasis on the contributions of H3 and H4 tails to oligonucleosome folding and stabilization. We evaluate both classic and recent experiments determining tail structures, effect of tail cleavage/loss, and posttranslational modifications of the tails on nucleosomes and nucleosome arrays, as well as inter-nucleosomal and inter-array interactions of the H3 and H4 N-terminal tails.

  14. Locating the neutrino interaction vertex with the help of electronic detectors in the OPERA experiment

    NASA Astrophysics Data System (ADS)

    Gornushkin, Yu. A.; Dmitrievsky, S. G.; Chukanov, A. V.

    2015-01-01

    The OPERA experiment is designed for the direct observation of the appearance of ντ from νμ → ντ oscillation in a νμ beam. A description of the procedure of neutrino interaction vertex localization (Brick Finding) by electronic detectors of a hybrid OPERA setup is presented. The procedure includes muon track and hadronic shower axis reconstruction and a determination of the target bricks with the highest probability to contain the vertex.

  15. Charm dimuon production in neutrino-nucleon interactions in the NOMAD experiment

    NASA Astrophysics Data System (ADS)

    Petti, Roberto; Samoylov, Oleg

    2012-09-01

    We present our new measurement of charm dimuon production in neutrino-iron interactions based upon the full statistics collected by the NOMAD experiment. After background subtraction we observe 15,340 charm dimuon events, providing the largest sample currently available. The analysis exploits the large inclusive charged current sample (about 9 million events after all analysis cuts) to constrain the total systematic uncertainty to about 2%. The extraction of strange sea and charm production parameters is also discussed.

  16. Charm dimuon production in neutrino-nucleon interactions in the NOMAD experiment

    NASA Astrophysics Data System (ADS)

    Petti, R.; Samoylov, O. B.

    2011-12-01

    We present our new measurement of charm dimuon production in neutrino-iron interactions based upon the full statistics collected by the NOMAD experiment. After background subtraction we observe 15,340 charm dimuon events, providing the largest sample currently available. The analysis exploits the large inclusive charged current sample (about 9 million events after all analysis cuts) to constrain the total systematic uncertainty to ˜2%. The extraction of strange sea and charm production parameters is also discussed.

  17. Search for neutrino oscillations in the MINOS experiment by using quasi-elastic interactions

    SciTech Connect

    Piteira, Rodolphe

    2005-09-29

    The enthusiasm of the scientific community for studying oscillations of neutrinos is equaled only by the mass of their detectors. The MINOS experiment determines and compares the near spectrum of muonic neutrinos from the NUMI beam to the far one, in order to measure two oscillation parameters: Δm$2\\atop{23}$ and sin2 (2θ23). The spectra are obtained by analyzing the charged current interactions which difficulty lies in identifying the interactions products (e.g. muons). An alternative method identifying the traces of muons, bent by the magnetic field of the detectors, and determining their energies is presented in this manuscript. The sensitivity of the detectors is optimal for the quasi-elastic interactions, for which a selection method is proposed, to study their oscillation. Even though it reduces the statistics, such a study introduces fewer systematic errors, constituting the ideal method on the long range.

  18. Maternal Experience of Interactions With Providers Among Mothers With Milk Supply Concern

    PubMed Central

    Flaherman, Valerie J.; Hicks, Katherine G.; Cabana, Michael D.; Lee, Kathryn A.

    2016-01-01

    Background Milk supply concern is the most common reason given by mothers for discontinuing breastfeeding. Objectives To describe maternal experiences of interactions with health care providers related to milk supply. Patients and methods Ten focus groups (N = 56 participants) were conducted among mothers who had had milk supply concern in the first month after birth. Group sessions were audio-recorded, transcribed, coded, and analyzed to identify themes. Results Interactions regarding milk supply concern evoked strong emotions, including gratitude, guilt, disappointment, and fear, and measurement of infant weight was frequently reported as a trigger for these emotions. Some mothers reported that experiencing “pressure” and “guilt” when providers emphasized exclusive breastfeeding led to suboptimal breastfeeding choices. Conclusions Interactions with providers about milk supply concern evoke strong emotions among mothers. Providers should be aware that how they communicate routine advice regarding infant weight and formula may have unintended consequences, including discontinuation of breastfeeding. PMID:22669980

  19. A structured architecture for advanced plasma control experiments

    SciTech Connect

    Penaflor, B.G.; Ferron, J.R.; Walker, M.L.

    1996-10-01

    Recent new and improved plasma control regimes have evolved from enhancements to the systems responsible for managing the plasma configuration on the DIII-D tokamak. The collection of hardware and software components designed for this purpose is known at DIII-D as the Plasma Control System or PCS. Several new user requirements have contributed to the rapid growth of the PCS. Experiments involving digital control of the plasma vertical position have resulted in the addition of new high performance processors to operate in real-time. Recent studies in plasma disruptions involving the use of neural network based software have resulted in an increase in the number of input diagnostic signals sampled. Better methods for estimating the plasma shape and position have brought about numerous software changes and the addition of several new code modules. Furthermore, requests for performing multivariable control and feedback on the current profile are continuing to add to the demands being placed on the PCS. To support all of these demands has required a structured yet flexible hardware and software architecture for maintaining existing capabilities and easily adding new ones. This architecture along with a general overview of the DIII-D Plasma Control System is described. In addition, the latest improvements to the PCS are presented.

  20. MOVING TO INEQUALITY: NEIGHBORHOOD EFFECTS AND EXPERIMENTS MEET STRUCTURE1

    PubMed Central

    Sampson, Robert J.

    2014-01-01

    The Moving to Opportunity (MTO) housing experiment has proven to be an important intervention not just in the lives of the poor, but in social science theories of neighborhood effects. Competing causal claims have been the subject of considerable disagreement, culminating in the debate between Clampet-Lundquist and Massey (2008) and Ludwig et al. (2008). This paper assesses the debate by clarifying analytically distinct questions posed by neighborhood-level theories, reconceptualizing selection bias as a fundamental social process worthy of study in its own right rather than as a statistical nuisance, and reconsidering the scientific method of experimentation, and hence causality, in the social world of the city. I also analyze MTO and independent survey data from Chicago to examine trajectories of residential attainment. Although MTO provides crucial leverage for estimating neighborhood effects on individuals, as proponents rightly claim, I demonstrate the implications imposed by a stratified urban structure and how MTO simultaneously provides a new window on the social reproduction of concentrated inequality. PMID:25360053

  1. Flume experiments on scour downstream of wood stream restoration structures

    NASA Astrophysics Data System (ADS)

    Pagliara, Stefano; Kurdistani, Sahameddin Mahmoudi

    2017-02-01

    River restoration aims to improve physical natural form and processes of a river. Techniques to control the riverbed, stabilize channel alignment, protect stream banks, and rebuild the natural habitat are an important part of river restoration projects. Rivers can be stabilized and habitat restored through techniques such as rebuilding meanders and pool-riffle sequences and managing large wood. Structures that limit channel width to accelerate the normal flows through the constricted section are referred to as stream deflectors. Single-wing, double-wing and triangular deflectors are the most commonly used types of this measure. Log-frame deflectors consist of a triangular log frame filled with rock. Deflector constructions singly or in series in low gradient meandering streams, divert base flows toward the center of the channel and, under certain conditions, increase the depth and velocity of flow thereby creating scour pools and enhancing fish habitat. Scour characteristics and morphologies downstream of log-frame deflectors have been analyzed at the hydraulic laboratory of the University of Pisa. All experiments have been carried out in clear water conditions. The results showed that the tailwater depth plays an important role on scour characteristics. In addition, it was experimentally proven that using log-frame deflectors instead of log-deflectors result in a better river bank protection. In this case, for all the tested hydraulic conditions, the scour hole never occurred close to the channel bank. Useful empirical relationships have been proposed in order to evaluate the main features of the scour geometry.

  2. Doped titanium oxide photcatalysts: Preparation, structure and interaction with viruses

    NASA Astrophysics Data System (ADS)

    Li, Qi

    Since the discovery of photoelectrochemical splitting of water on n-titanium oxide (n-TiO2) electrodes by Fujishima and Honda in 1972, there has been much interest in semiconductor-based materials as photocatalysts for both solar energy conversion and environmental applications in the past several decades. Among various semiconductor-based photocatalysts, TiO2 is the only candidate suitable for industrial use because of its high chemical stability, good photoactivity, relatively low cost, and nontoxicity. However, the photocatalytic capability of TiO 2 is limited to only ultraviolet (UV) light (wavelength, lambda, < 400 nm), seriously limiting its solar efficiency. In this study, both chemical and physical modification approaches were developed to extend the absorption band-edge of TiO2 into the visible light region with improved stability, photocatalytic efficiency and ease of the doping process. Two major approaches were used in the material synthesis and processing, including the ion-beam-assisted-deposition (IBAD) technique and sol-gel based processes. Both nitrogen-doped TiO2 (TiON) and nitrogen/palladium co-doped TiO2 (TiON/PdO) photocatalysts were created and their photocatalytic activity was investigated by the degradation of methylene blue (MB) and disinfection of bacteria and viruses under visible light illumination. The sol-gel process was optimized to produce high quality TiON-based photocatalysts by carefully modulating the precursor ratio and calcination temperature. A TiON inverse opal structure was created, which demonstrated enhanced visible light absorption and subsequently improved photocatalytic efficiency by the combination of chemical and physical modifications on n-TiO2. The effect of palladium dopant on the optical and photocatalytic properties of TiON/PdO photocatalyst was examined, which suggests that a careful optimization of the transition metal ion dopant concentration is needed to achieve high photocatalytic efficiency in these anion

  3. Solution structure and phospholipid interactions of the isolated voltage-sensor domain from KvAP.

    PubMed

    Butterwick, Joel A; MacKinnon, Roderick

    2010-11-05

    Voltage-sensor domains (VSDs) are specialized transmembrane segments that confer voltage sensitivity to many proteins such as ion channels and enzymes. The activities of these domains are highly dependent on both the chemical properties and the physical properties of the surrounding membrane environment. To learn about VSD-lipid interactions, we used nuclear magnetic resonance spectroscopy to determine the structure and phospholipid interface of the VSD from the voltage-dependent K(+) channel KvAP (prokaryotic Kv from Aeropyrum pernix). The solution structure of the KvAP VSD solubilized within phospholipid micelles is similar to a previously determined crystal structure solubilized by a nonionic detergent and complexed with an antibody fragment. The differences observed include a previously unidentified short amphipathic α-helix that precedes the first transmembrane helix and a subtle rigid-body repositioning of the S3-S4 voltage-sensor paddle. Using (15)N relaxation experiments, we show that much of the VSD, including the pronounced kink in S3 and the S3-S4 paddle, is relatively rigid on the picosecond-to-nanosecond timescale. In contrast, the kink in S3 is mobile on the microsecond-to-millisecond timescale and may act as a hinge in the movement of the paddle during channel gating. We characterized the VSD-phospholipid micelle interactions using nuclear Overhauser effect spectroscopy and showed that the micelle uniformly coats the KvAP VSD and approximates the chemical environment of a phospholipid bilayer. Using paramagnetically labeled phospholipids, we show that bilayer-forming lipids interact with the S3 and S4 helices more strongly than with S1 and S2.

  4. Positive everyday experiences interact with social support to predict depression in multiple sclerosis.

    PubMed

    Vargas, Gray A; Arnett, Peter A

    2010-11-01

    Both social support and stress predict depression in multiple sclerosis (MS) patients. Little work has been done on the relationship between positive life experiences and depression in this group. Ninety MS patients completed the Social Support Questionnaire (SSQ), the Hassles and Uplifts Scale (HUS), the Chicago Multiscale Depression Inventory (CMDI), and the Affective Reading Span Task (ARST). The Expanded Disability Status Scale (EDSS) was also used. Separate regression analyses were conducted with the EDSS entered at step 1, ARST memory bias score at step 2, SSQ at step 3, either Hassles or Uplifts at step 4, and the interaction term at step 5 to predict depression. Uplifts interacted significantly with social support to predict depression, but hassles did not. After considering disability level, memory bias, and social support and uplifts main effects, the interaction of uplifts and social support accounted for nearly 5% independent variance in depression (p < .05). These results suggest that the absence of uplifts, combined with low levels of social support, is related to depression in MS patients. More generally, these data indicate that it is important to study the absence of positive experiences along with stress and negative experiences in this population.

  5. Structural Optimization of a Force Balance Using a Computational Experiment Design

    NASA Technical Reports Server (NTRS)

    Parker, P. A.; DeLoach, R.

    2002-01-01

    This paper proposes a new approach to force balance structural optimization featuring a computational experiment design. Currently, this multi-dimensional design process requires the designer to perform a simplification by executing parameter studies on a small subset of design variables. This one-factor-at-a-time approach varies a single variable while holding all others at a constant level. Consequently, subtle interactions among the design variables, which can be exploited to achieve the design objectives, are undetected. The proposed method combines Modern Design of Experiments techniques to direct the exploration of the multi-dimensional design space, and a finite element analysis code to generate the experimental data. To efficiently search for an optimum combination of design variables and minimize the computational resources, a sequential design strategy was employed. Experimental results from the optimization of a non-traditional force balance measurement section are presented. An approach to overcome the unique problems associated with the simultaneous optimization of multiple response criteria is described. A quantitative single-point design procedure that reflects the designer's subjective impression of the relative importance of various design objectives, and a graphical multi-response optimization procedure that provides further insights into available tradeoffs among competing design objectives are illustrated. The proposed method enhances the intuition and experience of the designer by providing new perspectives on the relationships between the design variables and the competing design objectives providing a systematic foundation for advancements in structural design.

  6. Self-assembly of "Mickey Mouse" shaped colloids into tube-like structures: experiments and simulations.

    PubMed

    Wolters, Joost R; Avvisati, Guido; Hagemans, Fabian; Vissers, Teun; Kraft, Daniela J; Dijkstra, Marjolein; Kegel, Willem K

    2015-02-14

    The self-assembly of anisotropic patchy particles with a triangular shape was studied by experiments and computer simulations. The colloidal particles were synthesized in a two-step seeded emulsion polymerization process, and consist of a central smooth lobe connected to two rough lobes at an angle of ∼90°, resembling the shape of a "Mickey Mouse" head. Due to the difference in overlap volume, adding an appropriate depletant induces an attractive interaction between the smooth lobes of the colloids only, while the two rough lobes act as steric constraints. The essentially planar geometry of the Mickey Mouse particles is a first geometric deviation of dumbbell shaped patchy particles. This new geometry enables the formation of one-dimensional tube-like structures rather than spherical, essentially zero-dimensional micelles. At sufficiently strong attractions, we indeed find tube-like structures with the sticky lobes at the core and the non-sticky lobes pointing out as steric constraints that limit the growth to one direction, providing the tubes with a well-defined diameter but variable length both in experiments and simulations. In the simulations, we found that the internal structure of the tubular fragments could either be straight or twisted into so-called Bernal spirals.

  7. Structural Basis for Ca2+-mediated Interaction of the Perforin C2 Domain with Lipid Membranes*

    PubMed Central

    Yagi, Hiromasa; Conroy, Paul J.; Leung, Eleanor W. W.; Law, Ruby H. P.; Trapani, Joseph A.; Voskoboinik, Ilia; Whisstock, James C.; Norton, Raymond S.

    2015-01-01

    Natural killer cells and cytotoxic T-lymphocytes deploy perforin and granzymes to kill infected host cells. Perforin, secreted by immune cells, binds target membranes to form pores that deliver pro-apoptotic granzymes into the target cell. A crucial first step in this process is interaction of its C2 domain with target cell membranes, which is a calcium-dependent event. Some aspects of this process are understood, but many molecular details remain unclear. To address this, we investigated the mechanism of Ca2+ and lipid binding to the C2 domain by NMR spectroscopy and x-ray crystallography. Calcium titrations, together with dodecylphosphocholine micelle experiments, confirmed that multiple Ca2+ ions bind within the calcium-binding regions, activating perforin with respect to membrane binding. We have also determined the affinities of several of these binding sites and have shown that this interaction causes a significant structural rearrangement in CBR1. Thus, it is proposed that Ca2+ binding at the weakest affinity site triggers changes in the C2 domain that facilitate its interaction with lipid membranes. PMID:26306037

  8. Mining topological structures of protein-protein interaction networks for human brain-specific genes.

    PubMed

    Cui, W J; Gong, X J; Yu, H; Zhang, X C

    2015-10-16

    Compared to other placental mammals, humans have unique thinking and cognitive abilities because of their developed cerebral cortex composed of billions of neurons and synaptic connections. As the primary effectors of the mechanisms of life, proteins and their interactions form the basis of cellular and molecular functions in the living body. In this paper, we developed a pipeline for mining topological structures, identifying functional modules, and analyzing their functions from publically available datasets. A human brain-specific protein-protein interaction network with 1482 nodes and 3105 edges was built using a MapReduce based shortest path algorithm. Within this, 7 functional cliques were identified using a network clustering method, 98 hub proteins were obtained by the calculation of betweenness and connectivity, and 5 closest relationship to clique connector proteins were recognized by the combination scores of topological distance and gene ontology similarity. Furthermore, we discovered functional modules interacting with TP53 protein, which involves several fragmented research study conclusions and might be an important clue for further in vivo or in silico experiments to confirm these associations.

  9. Plant genotype shapes ant-aphid interactions: implications for community structure and indirect plant defense.

    PubMed

    Mooney, Kailen A; Agrawal, Anurag A

    2008-06-01

    Little is known about the mechanisms by which plant genotype shapes arthropod community structure. In a field experiment, we measured the effects of milkweed (Asclepias syriaca) genotype and ants on milkweed arthropods. Populations of the ant-tended aphid Aphis asclepiadis and the untended aphid Myzocallis asclepiadis varied eight- to 18-fold among milkweed genotypes, depending on aphid species and whether ants were present. There was no milkweed effect on predatory arthropods. Ants increased Aphis abundance 59%, decreased Myzocallis abundance 52%, and decreased predator abundance 56%. Milkweed genotype indirectly influenced ants via direct effects on Aphis and Myzocallis abundance. Milkweed genotype also modified ant-aphid interactions, influencing the number of ants attracted per Aphis and Myzocallis. While ant effects on Myzocallis were consistently negative, effects on Aphis ranged from antagonistic to mutualistic among milkweed genotypes. As a consequence of milkweed effects on ant-aphid interactions, ant abundance varied 13-fold among milkweed genotypes, and monarch caterpillar survival was negatively correlated with genetic variation in ant abundance. We speculate that heritable variation in milkweed phloem sap drives these effects on aphids, ants, and caterpillars. In summary, milkweed exerts genetic control over the interactions between aphids and an ant that provides defense against foliage-feeding caterpillars.

  10. Clinal resistance structure and pathogen local adaptation in a serpentine flax-flax rust interaction.

    PubMed

    Springer, Yuri P

    2007-08-01

    Because disease resistance is a hallmark signature of pathogen-mediated selection pressure on hosts, studies of resistance structure (the spatial distribution of disease resistance genes among conspecific host populations) can provide valuable insights into the influence of pathogens on host evolution and spatial variation in the magnitude of their effects. To date few studies of wild plant-pathogen interactions have characterized resistance structure by sampling across the host's biogeographic range, and only a handful have paired such investigations with studies of disease levels under natural conditions. I used a greenhouse cross-inoculation experiment to characterize genetic resistance of 16 populations of California dwarf flax (Hesperolinon californicum) to attack by multiple samples of the rust fungus Melampsora lini. I documented a latitudinal cline in resistance structure, manifest across the host's biogeographic range, which mirrored almost identically a cline in infection prevalence documented through field surveys of disease in study populations. These results provide empirical evidence for clinal patterns of antagonistic selection pressure, demonstrate that such patterns can be manifest across broad biogeographic scales, and suggest that rates of disease prevalence in wild plant populations may be tightly linked to the distribution of host resistance genes. Tests for local adaptation of the fungus revealed evidence of the phenomenon (significantly greater infection in sympatric plant-fungal pairings) as well as the potential for substantial bias to be introduced into statistical analyses by spatial patterns of host resistance structure.

  11. Elucidating the mechanisms of cooperative calcium-calmodulin interactions: a structural systems biology approach

    PubMed Central

    Valeyev, Najl V; Bates, Declan G; Heslop-Harrison, Pat; Postlethwaite, Ian; Kotov, Nikolay V

    2008-01-01

    Background Calmodulin is an important multifunctional molecule that regulates the activities of a large number of proteins in the cell. Calcium binding induces conformational transitions in calmodulin that make it specifically active to particular target proteins. The precise mechanisms underlying calcium binding to calmodulin are still, however, quite poorly understood. Results In this study, we adopt a structural systems biology approach and develop a mathematical model to investigate various types of cooperative calcium-calmodulin interactions. We compare the predictions of our analysis with physiological dose-response curves taken from the literature, in order to provide a quantitative comparison of the effects of different mechanisms of cooperativity on calcium-calmodulin interactions. The results of our analysis reduce the gap between current understanding of intracellular calmodulin function at the structural level and physiological calcium-dependent calmodulin target activation experiments. Conclusion Our model predicts that the specificity and selectivity of CaM target regulation is likely to be due to the following factors: variations in the target-specific Ca2+ dissociation and cooperatively effected dissociation constants, and variations in the number of Ca2+ ions required to bind CaM for target activation. PMID:18518982

  12. Glycodendritic structures based on Boltorn hyperbranched polymers and their interactions with Lens culinaris lectin.

    PubMed

    Arce, Eva; Nieto, Pedro M; Díaz, Vicente; Castro, Rossana García; Bernad, Antonio; Rojo, Javier

    2003-01-01

    Multivalent scaffolds bearing carbohydrates have been prepared to mediate biological processes where carbohydrates are involved. These systems consist of dendritic structures based on Boltorn H20 and H30 hyperbranched polymers to which carbohydrates are linked through a convenient spacer. Mannose has been chosen as a sugar unit to test the viability of this strategy. These glycodendritic compounds have been prepared in a few steps with good yields, showing a high solubility in physiological media and low toxicity. The binding of these dendritic polymers to the mannose-binding lectin Lens culinaris (LCA) was studied using STD-NMR experiments and quantitative precipitation assays. The results demonstrate the existence of a clear interaction between the mannose derivative systems and the Lens lectin where the dendritic scaffold does not have an important role in mannose binding but supplies the necessary multivalence for lectin cluster formation. These glycodendritic structures are able to interact with a receptor, and therefore they can be considered as promising tools for biological studies.

  13. Self-interacting inelastic dark matter: a viable solution to the small scale structure problems

    NASA Astrophysics Data System (ADS)

    Blennow, Mattias; Clementz, Stefan; Herrero-Garcia, Juan

    2017-03-01

    Self-interacting dark matter has been proposed as a solution to the small-scale structure problems, such as the observed flat cores in dwarf and low surface brightness galaxies. If scattering takes place through light mediators, the scattering cross section relevant to solve these problems may fall into the non-perturbative regime leading to a non-trivial velocity dependence, which allows compatibility with limits stemming from cluster-size objects. However, these models are strongly constrained by different observations, in particular from the requirements that the decay of the light mediator is sufficiently rapid (before Big Bang Nucleosynthesis) and from direct detection. A natural solution to reconcile both requirements are inelastic endothermic interactions, such that scatterings in direct detection experiments are suppressed or even kinematically forbidden if the mass splitting between the two-states is sufficiently large. Using an exact solution when numerically solving the Schrödinger equation, we study such scenarios and find regions in the parameter space of dark matter and mediator masses, and the mass splitting of the states, where the small scale structure problems can be solved, the dark matter has the correct relic abundance and direct detection limits can be evaded.

  14. The NASA-LaRC Controls-Structures Interaction (CSI) technology program

    NASA Astrophysics Data System (ADS)

    Anderson, Willard W.; Newsom, Jerry R.

    One of the main difficulties encountered in the design and implementation of control systems for spacecraft is the interaction between the control system and the flexibility of the vehicle. This difficulty has resulted in problems for a multitude of spacecraft including the earliest U.S. spacecraft, Explorer I; the Orbiting Geophysical Observatory III; Mariner 10; Galileo; and the Hubble Telescope. Recognizing the importance of the issue, NASA has an ongoing Controls-Structures Interaction (CSI) technology program to develop the methodology to design optimally and simultaneously both the control system and the structure. The CSI program is a multicenter program involving research teams from NASA's Langley Research Center (LaRC), Jet Propulsion Laboratory (JPL), and Marshall Space Flight Center (MSFC). JPL's area of interest is in optics-class vehicles and MSFC's in astrophysics vehicles. The aim of this paper is to explain the ongoing activities at LaRC, which are of a theoretical, ground test, and flight test nature, with focus on applications to spacecraft with multiple experiment-pointing mounts, large space radiometers, Space Station Freedom (SSF), and the Space Shuttle Remote Manipulator System (RMS).

  15. The NASA-LaRC Controls-Structures Interaction (CSI) technology program

    NASA Technical Reports Server (NTRS)

    Anderson, Willard W.; Newsom, Jerry R.

    1992-01-01

    One of the main difficulties encountered in the design and implementation of control systems for spacecraft is the interaction between the control system and the flexibility of the vehicle. This difficulty has resulted in problems for a multitude of spacecraft including the earliest U.S. spacecraft, Explorer I; the Orbiting Geophysical Observatory III; Mariner 10; Galileo; and the Hubble Telescope. Recognizing the importance of the issue, NASA has an ongoing Controls-Structures Interaction (CSI) technology program to develop the methodology to design optimally and simultaneously both the control system and the structure. The CSI program is a multicenter program involving research teams from NASA's Langley Research Center (LaRC), Jet Propulsion Laboratory (JPL), and Marshall Space Flight Center (MSFC). JPL's area of interest is in optics-class vehicles and MSFC's in astrophysics vehicles. The aim of this paper is to explain the ongoing activities at LaRC, which are of a theoretical, ground test, and flight test nature, with focus on applications to spacecraft with multiple experiment-pointing mounts, large space radiometers, Space Station Freedom (SSF), and the Space Shuttle Remote Manipulator System (RMS).

  16. Structure of human Sp140 PHD finger: an atypical fold interacting with Pin1.

    PubMed

    Zucchelli, Chiara; Tamburri, Simone; Quilici, Giacomo; Palagano, Eleonora; Berardi, Andrea; Saare, Mario; Peterson, Pärt; Bachi, Angela; Musco, Giovanna

    2014-01-01

    Sp140 is a nuclear leukocyte-specific protein involved in primary biliary cirrhosis and a risk factor in chronic lymphocytic leukemia. The presence of several chromatin related modules such as plant homeodomain (PHD), bromodomain and SAND domain suggests a role in chromatin-mediated regulation of gene expression; however, its real function is still elusive. Herein we present the solution structure of Sp140-PHD finger and investigate its role as epigenetic reader in vitro. Sp140-PHD presents an atypical PHD finger fold which does not bind to histone H3 tails but is recognized by peptidylprolyl isomerase Pin1. Pin1 specifically binds to a phosphopeptide corresponding to the L3 loop of Sp140-PHD and catalyzes cis-trans isomerization of a pThr-Pro bond. Moreover co-immunoprecipitation experiments demonstrate FLAG-Sp140 interaction with endogenous Pin1 in vivo. Overall these data include Sp140 in the list of the increasing number of Pin1 binders and expand the regulatory potential of PHD fingers as versatile structural platforms for diversified interactions.

  17. Fluid-structure interaction and structural analyses using a comprehensive mitral valve model with 3D chordal structure.

    PubMed

    Toma, Milan; Einstein, Daniel R; Bloodworth, Charles H; Cochran, Richard P; Yoganathan, Ajit P; Kunzelman, Karyn S

    2016-06-25

    Over the years, three-dimensional models of the mitral valve have generally been organized around a simplified anatomy. Leaflets have been typically modeled as membranes, tethered to discrete chordae typically modeled as one-dimensional, non-linear cables. Yet, recent, high-resolution medical images have revealed that there is no clear boundary between the chordae and the leaflets. In fact, the mitral valve has been revealed to be more of a webbed structure whose architecture is continuous with the chordae and their extensions into the leaflets. Such detailed images can serve as the basis of anatomically accurate, subject-specific models, wherein the entire valve is modeled with solid elements that more faithfully represent the chordae, the leaflets, and the transition between the two. These models have the potential to enhance our understanding of mitral valve mechanics and to re-examine the role of the mitral valve chordae, which heretofore have been considered to be 'invisible' to the fluid and to be of secondary importance to the leaflets. However, these new models also require a rethinking of modeling assumptions. In this study, we examine the conventional practice of loading the leaflets only and not the chordae in order to study the structural response of the mitral valve apparatus. Specifically, we demonstrate that fully resolved 3D models of the mitral valve require a fluid-structure interaction analysis to correctly load the valve even in the case of quasi-static mechanics. While a fluid-structure interaction mode is still more computationally expensive than a structural-only model, we also show that advances in GPU computing have made such models tractable. Copyright © 2016 John Wiley & Sons, Ltd.

  18. Robust Generation of Dynamic Data Structure Visualizations with Multiple Interaction Approaches

    ERIC Educational Resources Information Center

    Cross, James H., II; Hendrix, T. Dean; Umphress, David A.; Barowski, Larry A.; Jain, Jhilmil; Montgomery, Lacey N.

    2009-01-01

    jGRASP has three integrated approaches for interacting with its dynamic viewers for data structures: debugger, workbench, and text-based interactions that allow individual Java statements and expressions to be executed/evaluated. These approaches can be used together to provide a complementary set of interactions with the dynamic viewers. Data…

  19. Halogenated ligands and their interactions with amino acids: implications for structure-activity and structure-toxicity relationships.

    PubMed

    Kortagere, Sandhya; Ekins, Sean; Welsh, William J

    2008-09-01

    The properties of chemicals are rooted in their molecular structure. It follows that structural analysis of specific interactions between ligands and biomolecules at the molecular level is invaluable for defining structure-activity relationships (SARs) and structure-toxicity relationships (STRs). This study has elucidated the structural and molecular basis of interactions of biomolecules with alkyl and aryl halides that are extensively used as components in many commercial pesticides, disinfectants, and drugs. We analyzed the protein structures deposited in Protein Data Bank (PDB) for structural information associated with interactions between halogenated ligands and proteins. This analysis revealed distinct patterns with respect to the nature and structural characteristics of halogen interactions with specific types of atoms and groups in proteins. Fluorine had the highest propensity of interactions for glycine, while chlorine for leucine, bromine for arginine, and iodine for lysine. Chlorine, bromine and iodine had the lowest propensity of interactions for cysteine, while fluorine had a lowest propensity for proline. These trends for highest propensity shifted towards the hydrophobic residues for all the halogens when only interactions with the side chain were considered. Halogens had equal propensities of interaction for the halogen bonding partners (nitrogen and oxygen atoms), albeit with different geometries. The optimal angle for interactions with halogens was approximately 120 degrees for oxygen atoms, and approximately 96 degrees for nitrogen atoms. The distance distributions of halogens with various amino acids were mostly bimodal, and the angle distributions were unimodal. Insights gained from this study have implications for the rational design of safer drugs and commercially important chemicals.

  20. Estimating and Interpreting Latent Variable Interactions: A Tutorial for Applying the Latent Moderated Structural Equations Method

    ERIC Educational Resources Information Center

    Maslowsky, Julie; Jager, Justin; Hemken, Douglas

    2015-01-01

    Latent variables are common in psychological research. Research questions involving the interaction of two variables are likewise quite common. Methods for estimating and interpreting interactions between latent variables within a structural equation modeling framework have recently become available. The latent moderated structural equations (LMS)…

  1. Adaptive nonlinear polynomial neural networks for control of boundary layer/structural interaction

    NASA Technical Reports Server (NTRS)

    Parker, B. Eugene, Jr.; Cellucci, Richard L.; Abbott, Dean W.; Barron, Roger L.; Jordan, Paul R., III; Poor, H. Vincent

    1993-01-01

    The acoustic pressures developed in a boundary layer can interact with an aircraft panel to induce significant vibration in the panel. Such vibration is undesirable due to the aerodynamic drag and structure-borne cabin noises that result. The overall objective of this work is to develop effective and practical feedback control strategies for actively reducing this flow-induced structural vibration. This report describes the results of initial evaluations using polynomial, neural network-based, feedback control to reduce flow induced vibration in aircraft panels due to turbulent boundary layer/structural interaction. Computer simulations are used to develop and analyze feedback control strategies to reduce vibration in a beam as a first step. The key differences between this work and that going on elsewhere are as follows: that turbulent and transitional boundary layers represent broadband excitation and thus present a more complex stochastic control scenario than that of narrow band (e.g., laminar boundary layer) excitation; and secondly, that the proposed controller structures are adaptive nonlinear infinite impulse response (IIR) polynomial neural network, as opposed to the traditional adaptive linear finite impulse response (FIR) filters used in most studies to date. The controllers implemented in this study achieved vibration attenuation of 27 to 60 dB depending on the type of boundary layer established by laminar, turbulent, and intermittent laminar-to-turbulent transitional flows. Application of multi-input, multi-output, adaptive, nonlinear feedback control of vibration in aircraft panels based on polynomial neural networks appears to be feasible today. Plans are outlined for Phase 2 of this study, which will include extending the theoretical investigation conducted in Phase 2 and verifying the results in a series of laboratory experiments involving both bum and plate models.

  2. The front line of social capital creation--a natural experiment in symbolic interaction.

    PubMed

    Patulny, Roger; Siminski, Peter; Mendolia, Silvia

    2015-01-01

    This paper offers theoretical and empirical contributions to understanding the micro-sociological processes behind the creation of social capital. Theoretically, we argue that the emotional and shared experience of participating in symbolic interaction rituals may affect social capital in four different ways, via: (i) a 'citizenship' effect, connecting participants symbolically to the broader, civic society; (ii) a 'supportive' effect, bonding participants with each other; (iii) an exclusive 'tribal' effect, which crowds-out connections with other groups and the wider society; and (iv) an 'atomising' effect, whereby intense experiences create mental health problems that damage social capital. We illustrate this with a case study of Australian veterans of the Vietnam War. The randomness of the National Service conscription lotteries of that era translates into a high-quality natural experiment. We formulate several hypotheses about which of the four effects dominates for veterans who participated in the 'symbolic interaction' of training and deployment. We test these hypotheses using data from the 2006 Australian Census of Population and Housing, and the NSW 45 & Up Study. We found that war service reduced 'bonding' social capital, but increased 'bridging' social capital, and this is not explained completely by mental health problems. This suggests that while the combined 'tribal' and 'atomizing' effects of service outweigh the 'supportive' effects, the 'citizenship' effect is surprisingly robust. Although they feel unsupported and isolated, veterans are committed to their community and country. These paradoxical findings suggest that social capital is formed through symbolic interaction. The emotional and symbolic qualities of interaction rituals may formulate non-strategic (perhaps irrational) connections with society regardless of the status of one's personal support networks.

  3. The interaction of early life experiences with COMT val158met affects anxiety sensitivity.

    PubMed

    Baumann, C; Klauke, B; Weber, H; Domschke, K; Zwanzger, P; Pauli, P; Deckert, J; Reif, A

    2013-11-01

    The pathogenesis of anxiety disorders is considered to be multifactorial with a complex interaction of genetic factors and individual environmental factors. Therefore, the aim of this study was to examine gene-by-environment interactions of the genes coding for catechol-O-methyltransferase (COMT) and monoamine oxidase A (MAOA) with life events on measures related to anxiety. A sample of healthy subjects (N = 782; thereof 531 women; mean age M = 24.79, SD = 6.02) was genotyped for COMT rs4680 and MAOA-uVNTR (upstream variable number of tandem repeats), and was assessed for childhood adversities [Childhood Trauma Questionnaire (CTQ)], anxiety sensitivity [Anxiety Sensitivity Index (ASI)] and anxious apprehension [Penn State Worry Questionnaire (PSWQ)]. Main and interaction effects of genotype, environment and gender on measures related to anxiety were assessed by means of regression analyses. Association analysis showed no main gene effect on either questionnaire score. A significant interactive effect of childhood adversities and COMT genotype was observed: Homozygosity for the low-active met allele and high CTQ scores was associated with a significant increment of explained ASI variance [R(2) = 0.040, false discovery rate (FDR) corrected P = 0.04]. A borderline interactive effect with respect to MAOA-uVNTR was restricted to the male subgroup. Carriers of the low-active MAOA allele who reported more aversive experiences in childhood exhibited a trend for enhanced anxious apprehension (R(2) = 0.077, FDR corrected P = 0.10). Early aversive life experiences therefore might increase the vulnerability to anxiety disorders in the presence of homozygosity for the COMT 158met allele or low-active MAOA-uVNTR alleles.

  4. Differential effects of intranasal oxytocin on sexual experiences and partner interactions in couples.

    PubMed

    Behnia, Behnoush; Heinrichs, Markus; Bergmann, Wiebke; Jung, Stefanie; Germann, Janine; Schedlowski, Manfred; Hartmann, Uwe; Kruger, Tillmann H C

    2014-03-01

    Knowledge about the effects of the neuropeptide oxytocin (OXT) on human sexual behaviors and partner interactions remains limited. Based on our previous studies, we hypothesize that OXT should be able to positively influence parameters of sexual function and couple interactions. Employing a naturalistic setting involving 29 healthy heterosexual couples (n=58 participants), we analyzed the acute effects of intranasally administered OXT (24IU) on sexual drive, arousal, orgasm and refractory aspects of sexual behavior together with partner interactions. Data were assessed by psychometric instruments (Acute Sexual Experiences Scale, Arizona Sexual Experience Scale) as well as biomarkers, such as cortisol, α-amylase and heart rate. Intranasal OXT administration did not alter "classical" parameters of sexual function, such as sexual drive, arousal or penile erection and lubrication. However, analysis of variance and a hierarchical linear model (HLM) revealed specific effects related to the orgasmic/post-orgasmic interval as well as parameters of partner interactions. According to HLM analysis, OXT increased the intensity of orgasm, contentment after sexual intercourse and the effect of study participation. According to ANOVA analysis, these effects were more pronounced in men. Men additionally indicated higher levels of sexual satiety after sexual intercourse with OXT administration. Women felt more relaxed and subgroups indicated better abilities to share sexual desires or to empathize with their partners. The effect sizes were small to moderate. Biomarkers indicated moderate psychophysiological activation but were not affected by OXT, gender or method of contraception. Using a naturalistic setting, intranasal OXT administration in couples exerted differential effects on parameters of sexual function and partner interactions. These results warrant further investigations, including subjects with sexual and relationship problems.

  5. Interaction of some limbic structures which exert inhibitory effect on corticosterone secretion.

    PubMed

    Suárez, M; Perassi, N I

    1990-12-01

    The interaction between limbic structures which exert inhibitory influence on corticosterone secretion was investigated in the rat. The following experiments were performed: 1) electrical stimulation at mammillary medial nucleus (MMN) in rats with lesioned anterodrosal thalami nucleus (ADTN) or intermediate tegmental area; 2) electrical stimulation at ADTN in rats with lesioned retrosplenial cortex (RC). Bilateral stimulation at MMN in ADTN or RC-lesioned rats produces an increase in plasma corticosterone concentration. In animals with lesioned RC, values of plasma corticosterone after stimulation at ADTN were higher than before stimulation. Taking into consideration that electrical stimulation of MMN or ADTN in intact rats produces a decrease in plasma corticosterone concentration, these studies demonstrate that MMN and ADTN exert inhibitory influence on corticoadrenal activity only when their projection areas remain intact.

  6. Structural and functional analyses of PAS domain interactions of the clock proteins Drosophila PERIOD and mouse PERIOD2.

    PubMed

    Hennig, Sven; Strauss, Holger M; Vanselow, Katja; Yildiz, Ozkan; Schulze, Sabrina; Arens, Julia; Kramer, Achim; Wolf, Eva

    2009-04-28

    PERIOD proteins are central components of the Drosophila and mammalian circadian clocks. The crystal structure of a Drosophila PERIOD (dPER) fragment comprising two PER-ARNT-SIM (PAS) domains (PAS-A and PAS-B) and two additional C-terminal alpha-helices (alphaE and alphaF) has revealed a homodimer mediated by intermolecular interactions of PAS-A with tryptophane 482 in PAS-B and helix alphaF. Here we present the crystal structure of a monomeric PAS domain fragment of dPER lacking the alphaF helix. Moreover, we have solved the crystal structure of a PAS domain fragment of the mouse PERIOD homologue mPER2. The mPER2 structure shows a different dimer interface than dPER, which is stabilized by interactions of the PAS-B beta-sheet surface including tryptophane 419 (equivalent to Trp482dPER). We have validated and quantitatively analysed the homodimer interactions of dPER and mPER2 by site-directed mutagenesis using analytical gel filtration, analytical ultracentrifugation, and co-immunoprecipitation experiments. Furthermore we show, by yeast-two-hybrid experiments, that the PAS-B beta-sheet surface of dPER mediates interactions with TIMELESS (dTIM). Our study reveals quantitative and qualitative differences between the homodimeric PAS domain interactions of dPER and its mammalian homologue mPER2. In addition, we identify the PAS-B beta-sheet surface as a versatile interaction site mediating mPER2 homodimerization in the mammalian system and dPER-dTIM heterodimer formation in the Drosophila system.

  7. Predictive Bcl-2 Family Binding Models Rooted in Experiment or Structure

    PubMed Central

    DeBartolo, Joe; Dutta, Sanjib; Reich, Lothar; Keating, Amy E.

    2013-01-01

    Proteins of the Bcl-2 family either enhance or suppress programmed cell death and are centrally involved in cancer development and resistance to chemotherapy. BH3 (Bcl-2 homology 3)-only Bcl-2 proteins promote cell death by docking an α-helix into a hydrophobic groove on the surface of one or more of five pro-survival Bcl-2 receptor proteins. There is high structural homology within the pro-death and pro-survival families, yet a high degree of interaction specificity is nevertheless encoded, posing an interesting and important molecular recognition problem. Understanding protein features that dictate Bcl-2 interaction specificity is critical for designing peptide-based cancer therapeutics and diagnostics. In this study, we present peptide SPOT arrays and deep sequencing data from yeast display screening experiments that significantly expand the BH3 sequence space that has been experimentally tested for interaction with five human anti-apoptotic receptors. These data provide rich information about the determinants of Bcl-2 family specificity. To interpret and use the information, we constructed two simple data-based models that can predict affinity and specificity when evaluated on independent data sets within a limited sequence space. We also constructed a novel structure-based statistical potential, called STATIUM, which is remarkably good at predicting Bcl-2 affinity and specificity, especially considering it is not trained on experimental data. We compare the performance of our three models to each other and to alternative structure-based methods and discuss how such tools can guide prediction and design of new Bcl-2 family complexes. PMID:22617328

  8. Investigating lava-substrate interactions through flow experiments with syrup, wax, and molten basalt

    NASA Astrophysics Data System (ADS)

    Rumpf, M. E.; Lev, E.

    2015-12-01

    Among the many factors influencing the complex process of lava flow emplacement, the interaction with the substrate onto which flow is emplaced plays a central role. Lava flows are rarely emplaced onto smooth or regular surfaces. For example, at Kīlauea Volcano, Hawai'i, lava flows regularly flow over solid rock, vegetation, basaltic or silica sand, and man-made materials, including asphalt and concrete. In situ studies of lava-substrate interactions are inherently difficult, and often dangerous, to carry-out, requiring the design of controllable laboratory experiments. We investigate the effects of substrate grain size, cohesion, and roughness on flow mobility and morphology through a series of flow experiments using analog materials and molten basalt. We have developed a series of experiments that allow for adjustable substrate parameters and analyze their effects on lava flow emplacement. The first set of experiments are performed at the Fluids Mechanics Laboratory at the Lamont-Doherty Earth Observatory and focus on two analog materials: polyethylene glycol (PEG), a commercially available wax, and corn syrup. The fluids were each extruded onto a series of scaled substrate beds to replicate the emplacement of lava in a natural environment. Preliminary experiments demonstrated that irregular topography, particularly topography with a height amplitude similar to that of the flow itself, can affect flow morphology, width, and velocity by acting as local barriers or culverts to the fluid. This is expected from observations of fluid flow in natural environments. A follow-up set of experiments will be conducted in Fall 2015 at the Syracuse University (SU) Lava Project Lab. In this set, we will pour molten basalt directly onto a series of substrates representing natural environments found on the Earth and other rocky bodies in the Solar System. These experiments will allow for analysis of the effects of basaltic composition and high temperatures on lava-substrate heat

  9. Shock interaction with organized structures: Theory and computation

    NASA Astrophysics Data System (ADS)

    Ding, Zhong

    Unsteady interactions between shocks and turbulence are important phenomena frequently encountered in high-speed flows. In this dissertation the problem of a shock interaction with an entropy spot is studied by means of both theoretical analysis and nonlinear computation. The main objective of the studies is to apply both theoretical and computational approaches to study the physics underlying such shock interaction process. The theoretical analysis is based on the Fourier decomposition of the upstream disturbance, the interaction of each Fourier mode with the shock, and the reconstruction of the downstream disturbance via the inverse Fourier transform. The theory is linear in that it assumes the principle of superposition and that the Rankine-Hugoniot relations are linearized about the mean position of the shock. The numerical simulation is carried out within the framework of the unsteady and compressible Euler equations, coupled with an equation for the shock motion, solved numerically by a sixth-order accurate spatial scheme and a fourth-order Runge-Kutta time-integration method. Analyses of the results are concentrated on the case of a Mach 2.0 shock interaction with an entropy spot that has a Gaussian density distribution. The theoretical analysis and the numerical simulation are verified with each other for small amplitude disturbances. The roles of the evanescent and the non-evanescent waves and the mechanisms for downstream disturbance generations are explored in details. In addition, the quasi three-dimensional interaction between a shock and a vortex ring is investigated computationally within the framework of the axisymmetric Euler equations. The vortex ring, which is based on Lamb's formula, has an upstream circulation Gamma = 0.01 and its aspect ratio R lies in the range 8 ≤ R ≤ 100. The shock Mach number varies in the range 1.1 ≤ M1 ≤ 1.8. The interaction results in the streamwise compression of the vortex core and the generation of a toroidal

  10. Balancing positive and negative plant interactions: how mosses structure vascular plant communities.

    PubMed

    Gornall, Jemma L; Woodin, Sarah J; Jónsdóttir, Ingibjorg S; van der Wal, René

    2011-07-01

    Our understanding of positive and negative plant interactions is primarily based on vascular plants, as is the prediction that facilitative effects dominate in harsh environments. It remains unclear whether this understanding is also applicable to moss-vascular plant interactions, which are likely to be influential in low-temperature environments with extensive moss ground cover such as boreal forest and arctic tundra. In a field experiment in high-arctic tundra, we investigated positive and negative impacts of the moss layer on vascular plants. Ramets of the shrub Salix polaris, herb Bistorta vivipara, grass Alopecurus borealis and rush Luzula confusa were transplanted into plots manipulated to contain bare soil, shallow moss (3 cm) and deep moss (6 cm) and harvested after three growing seasons. The moss layer had both positive and negative impacts upon vascular plant growth, the relative extent of which varied among vascular plant species. Deep moss cover reduced soil temperature and nitrogen availability, and this was reflected in reduced graminoid productivity. Shrub and herb biomass were greatest in shallow moss, where soil moisture also appeared to be highest. The relative importance of the mechanisms by which moss may influence vascular plants, through effects on soil temperature, moisture and nitrogen availability, was investigated in a phytotron growth experiment. Soil temperature, and not nutrient availability, determined Alopecurus growth, whereas Salix only responded to increased temperature if soil nitrogen was also increased. We propose a conceptual model showing the relative importance of positive and negative influences of the moss mat on vascular plants along a gradient of moss depth and illustrate species-specific outcomes. Our findings suggest that, through their strong influence on the soil environment, mat-forming mosses structure the composition of vascular plant communities. Thus, for plant interaction theory to be widely applicable to

  11. The effect of task and pitch structure on pitch-time interactions in music.

    PubMed

    Prince, Jon B; Schmuckler, Mark A; Thompson, William F

    2009-04-01

    Musical pitch-time relations were explored by investigating the effect of temporal variation on pitch perception. In Experiment 1, trained musicians heard a standard tone followed by a tonal context and then a comparison tone. They then performed one of two tasks. In the cognitive task, they indicated whether the comparison tone was in the key of the context. In the perceptual task, they judged whether the comparison tone was higher or lower than the standard tone. For both tasks, the comparison tone occurred early, on time, or late with respect to temporal expectancies established by the context. Temporal variation did not affect accuracy in either task. Experiment 2 used the perceptual task and varied the pitch structure by employing either a tonal or an atonal context. Temporal variation did not affect accuracy for tonal contexts, but did for atonal contexts. Experiment 3 replicated these results and controlled potential confounds. We argue that tonal contexts bias attention toward pitch and eliminate effects of temporal variation, whereas atonal contexts do not, thus fostering pitch-time interactions.

  12. Influence of Height in Simulation of Soil Structure Interaction Problems with Dampers

    NASA Astrophysics Data System (ADS)

    Bogdanovic, Aleksandra; Edip, Kemal; Stojmanovska, Marta

    2016-12-01

    In numerical simulation of soil structure interaction problems the presence of dampers in the frame is an advantage yet a special topic to be considered. This paper presents valuable observation on the dynamic soil structure interaction analysis of multi storey frames and considers the effect of height in simulation of soil structure interaction problems. Comparison of these problems has been done by comparing the obtained results from different set up in the software ANSYS. The results of numerical analysis illustrate that it has to be paid more attention when considering the structures not alone but also considering the effect of soil medium.

  13. Analysis of high speed flow, thermal and structural interactions

    NASA Technical Reports Server (NTRS)

    Thornton, Earl A.

    1994-01-01

    Research for this grant focused on the following tasks: (1) the prediction of severe, localized aerodynamic heating for complex, high speed flows; (2) finite element adaptive refinement methodology for multi-disciplinary analyses; (3) the prediction of thermoviscoplastic structural response with rate-dependent effects and large deformations; (4) thermoviscoplastic constitutive models for metals; and (5) coolant flow/structural heat transfer analyses.

  14. SAFAS: Unifying Form and Structure through Interactive 3D Simulation

    ERIC Educational Resources Information Center

    Polys, Nicholas F.; Bacim, Felipe; Setareh, Mehdi; Jones, Brett D.

    2015-01-01

    There has been a significant gap between the tools used for the design of a building's architectural form and those that evaluate the structural physics of that form. Seeking to bring the perspectives of visual design and structural engineering closer together, we developed and evaluated a design tool for students and practitioners to explore the…

  15. The experience of agency in human-computer interactions: a review

    PubMed Central

    Limerick, Hannah; Coyle, David; Moore, James W.

    2014-01-01

    The sense of agency is the experience of controlling both one’s body and the external environment. Although the sense of agency has been studied extensively, there is a paucity of studies in applied “real-life” situations. One applied domain that seems highly relevant is human-computer-interaction (HCI), as an increasing number of our everyday agentive interactions involve technology. Indeed, HCI has long recognized the feeling of control as a key factor in how people experience interactions with technology. The aim of this review is to summarize and examine the possible links between sense of agency and understanding control in HCI. We explore the overlap between HCI and sense of agency for computer input modalities and system feedback, computer assistance, and joint actions between humans and computers. An overarching consideration is how agency research can inform HCI and vice versa. Finally, we discuss the potential ethical implications of personal responsibility in an ever-increasing society of technology users and intelligent machine interfaces. PMID:25191256

  16. Triadic social interactions operate across time: a field experiment with wild chimpanzees.

    PubMed

    Wittig, Roman M; Crockford, Catherine; Langergraber, Kevin E; Zuberbühler, Klaus

    2014-03-22

    Social animals cooperate with bonding partners to outcompete others. Predicting a competitor's supporter is likely to be beneficial, regardless of whether the supporting relationship is stable or transient, or whether the support happens immediately or later. Although humans make such predictions frequently, it is unclear to what extent animals have the cognitive abilities to recognize others' transient bond partners and to predict others' coalitions that extend beyond the immediate present. We conducted playback experiments with wild chimpanzees to test this. About 2 h after fighting, subjects heard recordings of aggressive barks of a bystander, who was or was not a bond partner of the former opponent. Subjects looked longer and moved away more often from barks of the former opponents' bond partners than non-bond partners. In an additional experiment, subjects moved away more from barks than socially benign calls of the same bond partner. These effects were present despite differences in genetic relatedness and considerable time delays between the two events. Chimpanzees, it appears, integrate memories of social interactions from different sources to make inferences about current interactions. This ability is crucial for connecting triadic social interactions across time, a requirement for predicting aggressive support even after a time delay.

  17. Structural determinants for NF-Y/DNA interaction at the CCAAT box.

    PubMed

    Nardone, Valentina; Chaves-Sanjuan, Antonio; Nardini, Marco

    2016-09-25

    The recently determined crystal structures of the sequence-specific transcription factor NF-Y have illuminated the structural mechanism underlying transcription at the CCAAT box. NF-Y is a trimeric protein complex composed by the NF-YA, NF-YB, and NF-YC subunits. NF-YB and NF-YC contain a histone-like domain and assemble on a head-to-tail fashion to form a dimer, which provides the structural scaffold for the DNA sugar-phosphate backbone binding (mimicking the nucleosome H2A/H2B-DNA assembly) and for the interaction with NF-YA. The NF-YA subunit hosts two structurally extended α-helices; one is involved in NF-YB/NF-YC binding and the other inserts deeply into the DNA minor groove, providing exquisite sequence-specificity for recognition and binding of the CCAAT box. The analysis of these structural data is expected to serve as a powerful guide for future experiments aimed at understanding the role of post-translational modification at NF-Y regulation sites and to unravel the three-dimensional architecture of higher order complexes formed between NF-Y and other transcription factors that act synergistically for transcription activation. Moreover, these structures represent an excellent starting point to challenge the formation of a stable hybrid nucleosome between NF-Y and core histone proteins, and to rationalize the fine molecular details associated with the wide combinatorial association of plant NF-Y subunits. This article is part of a Special Issue entitled: Nuclear Factor Y in Development and Disease, edited by Prof. Roberto Mantovani.

  18. Norm Development, Decision Making, and Structuration in CMC Group Interaction

    ERIC Educational Resources Information Center

    Turman, Paul D.

    2005-01-01

    The use of new and advanced technologies has a significant potential to impact the way students communicate in a number of contexts and settings. Many students will find themselves in both academic and career situations where computer-mediated communication (CMC) group interaction will be necessary. As a result, it is important to integrate…

  19. Separating the effects of intra- and interspecific age-structured interactions in an experimental fish assemblage

    USGS Publications Warehouse

    Taylor, R.C.; Trexler, J.C.; Loftus, W.F.

    2001-01-01

    We documented patterns of age-structured biotic interactions in four mesocosm experiments with an assemblage of three species of co-occurring fishes from the Florida Everglades, the eastern mosquitofish (Gambusia holbrooki), sailfin molly (Poecilia latipinna), and bluefin killifish (Lucania goodei). These species were chosen based on their high abundance and overlapping diets. Juvenile mosquitofish and sailfin mollies, at a range of densities matching field estimates, were maintained in the presence of adult mosquitofish, sailfin mollies, and bluefin killifish to test for effects of competition and predation on juvenile survival and growth. The mesocosms held 1,200 1 of water and all conditions were set to simulate those in Shark River Slough, Everglades National Park (ENP), USA. We placed floating mats of periphyton and bladderwort in each tank in standard volumes that matched field values to provide cover and to introduce invertebrate prey. Of 15 possible intra- and interspecific age-structured interactions, we found 7 to be present at the densities of these fish found in Shark River Slough marshes. Predation by adult mosquitofish on juvenile fish, including conspecifics, was the strongest effect observed. We also observed growth limitation in mosquitofish and sailfin molly juveniles from intra- and interspecific competition. When maintained at high densities, juvenile mosquitofish changed their diets to include more cladocerans and fewer chironomid larvae relative to low densities. We estimated size-specific gape limitation by adult mosquitofish when consuming juvenile mosquitofish and sailfin mollies. At high field densities, intraspecific competition might prolong the time period when juveniles are vulnerable to predation by adult mosquitofish. These results suggest that path analysis, or other techniques used to document food-web interactions, must include age-specific roles of these fishes.

  20. Controls Astrophysics and Structures Experiment in Space (CASES) advanced studies and planning

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    1989-01-01

    The CASES (Controls, Astrophysics, and Structures Experiment in Space) program consists of a flight demonstration of CSI (Controls-Structures Interactions) technology on the Space Shuttle. The basis structure consists of a 32 m deployable boom with actuators and sensors distributed along its length. Upon deployment from the Orbiter bay, the CASES structure will be characterized dynamically and its deformations controlled by a series of experimental control laws; and cold gas thrusters at its tip will be used to orient the Orbiter to a fixed celestial reference. The scientific observations will consist of hard x-ray imaging, at high resolution, of the Sun and the Galactic center. The hard x-ray observations require stable (few arc min) pointing at these targets for one or more position-sensitive proportional counters in the Orbiter bay, which view the object to be imaged through an aperture-encoding mask at the boom tip. This report gives the concensus developed at the second CASES Science Working Group meeting, which took place at NASA Marshall Space Flight Center May 16-17, 1990. An earlier paper and scientific summaries are available and form the basis for the present discussion.