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Sample records for adaptive life simulator

  1. Adaptive life simulator: A novel approach to modeling the cardiovascular system

    SciTech Connect

    Kangas, L.J.; Keller, P.E.; Hashem, S.

    1995-06-01

    In this paper, an adaptive life simulator (ALS) is introduced. The ALS models a subset of the dynamics of the cardiovascular behavior of an individual by using a recurrent artificial neural network. These models are developed for use in applications that require simulations of cardiovascular systems, such as medical mannequins, and in medical diagnostic systems. This approach is unique in that each cardiovascular model is developed from physiological measurements of an individual. Any differences between the modeled variables and the actual variables of an individual can subsequently be used for diagnosis. This approach also exploits sensor fusion applied to biomedical sensors. Sensor fusion optimizes the utilization of the sensors. The advantage of sensor fusion has been demonstrated in applications including control and diagnostics of mechanical and chemical processes.

  2. Adaptive Sampling in Hierarchical Simulation

    SciTech Connect

    Knap, J; Barton, N R; Hornung, R D; Arsenlis, A; Becker, R; Jefferson, D R

    2007-07-09

    We propose an adaptive sampling methodology for hierarchical multi-scale simulation. The method utilizes a moving kriging interpolation to significantly reduce the number of evaluations of finer-scale response functions to provide essential constitutive information to a coarser-scale simulation model. The underlying interpolation scheme is unstructured and adaptive to handle the transient nature of a simulation. To handle the dynamic construction and searching of a potentially large set of finer-scale response data, we employ a dynamic metric tree database. We study the performance of our adaptive sampling methodology for a two-level multi-scale model involving a coarse-scale finite element simulation and a finer-scale crystal plasticity based constitutive law.

  3. Predicting life-history adaptations to pollutants

    SciTech Connect

    Maltby, L.

    1995-12-31

    Animals may adapt to pollutant stress so that individuals from polluted environments are less susceptible than those from unpolluted environments. In addition to such direct adaptations, animals may respond to pollutant stress by life-history modifications; so-called indirect adaptations. This paper will demonstrate how, by combining life-history theory and toxicological data, it is possible to predict stress-induced alterations in reproductive output and offspring size. Pollutant-induced alterations in age-specific survival in favor of adults and reductions in juvenile growth, conditions are predicted to select for reduced investment in reproduction and the allocation of this investment into fewer, larger offspring. Field observations on the freshwater crustaceans, Asellus aquaticus and Gammarus pulex, support these predictions. Females from metal-polluted sites had lower investment in reproduction and produced larger offspring than females of the same species from unpolluted sites. Moreover, interpopulation differences in reproductive biology persisted in laboratory cultures indicating that they had a genetic basis and were therefore due to adaptation rather than acclimation. The general applicability of this approach will be considered.

  4. Binocular adaptive optics visual simulator.

    PubMed

    Fernández, Enrique J; Prieto, Pedro M; Artal, Pablo

    2009-09-01

    A binocular adaptive optics visual simulator is presented. The instrument allows for measuring and manipulating ocular aberrations of the two eyes simultaneously, while the subject performs visual testing under binocular vision. An important feature of the apparatus consists on the use of a single correcting device and wavefront sensor. Aberrations are controlled by means of a liquid-crystal-on-silicon spatial light modulator, where the two pupils of the subject are projected. Aberrations from the two eyes are measured with a single Hartmann-Shack sensor. As an example of the potential of the apparatus for the study of the impact of the eye's aberrations on binocular vision, results of contrast sensitivity after addition of spherical aberration are presented for one subject. Different binocular combinations of spherical aberration were explored. Results suggest complex binocular interactions in the presence of monochromatic aberrations. The technique and the instrument might contribute to the better understanding of binocular vision and to the search for optimized ophthalmic corrections.

  5. Coordinated adaptive filters for motion simulators.

    NASA Technical Reports Server (NTRS)

    Parrish, R. V.; Dieudonne, J. E.; Bowles, R. L.; Martin, D. J.

    1973-01-01

    A new approach to providing motion drive signals to a flight simulator utilizing coordinated adaptive filters is presented. Some motivation for the use of coordinated washout is discussed, along with conditions that determine the burden of coordination. The coordinated adaptive filters are derived, based on continuous steepest descent, and the application of the filters to simulated flight data is demonstrated.

  6. Link Dependent Adaptive Radio Simulation

    DTIC Science & Technology

    2014-06-01

    14. ABSTRACT This paper shows the optimized Link Dependent Adaptive Radio (LDAR) using the variable QAM OFDM modulation size which adapts to channel...bit error rate (BER), Orthogonal Frequency Division Multiplexing ( OFDM ) 16. SECURITY CLASSIFICATION OF: Unclassified 17. LIMITATION OF ABSTRACT...using the variable QAM OFDM modulation size which adapts to channel conditions. The LDAR enhanced performance is illustrated by use of a flight path

  7. The Adaptive Multi-scale Simulation Infrastructure

    SciTech Connect

    Tobin, William R.

    2015-09-01

    The Adaptive Multi-scale Simulation Infrastructure (AMSI) is a set of libraries and tools developed to support the development, implementation, and execution of general multimodel simulations. Using a minimal set of simulation meta-data AMSI allows for minimally intrusive work to adapt existent single-scale simulations for use in multi-scale simulations. Support for dynamic runtime operations such as single- and multi-scale adaptive properties is a key focus of AMSI. Particular focus has been spent on the development on scale-sensitive load balancing operations to allow single-scale simulations incorporated into a multi-scale simulation using AMSI to use standard load-balancing operations without affecting the integrity of the overall multi-scale simulation.

  8. Morphological adaptations to marine life in snakes.

    PubMed

    Brischoux, François; Shine, Richard

    2011-05-01

    We investigated morphological adaptations to aquatic life within animals that exhibit a structurally simple, elongate body form, i.e., snakes. This linear body plan should impose different biomechanical constraints than the classical streamlined body shape associated with propulsion by fins, feet, or wings. Our measurements of general body shape of terrestrial, amphibious, and marine snakes (all from the same phylogenetic lineage, the Elapidae) show that seasnakes display specialized morphological attributes for life in water. Most notably, the cross-sectional body shape is circular in terrestrial snakes but dorso-ventrally elongated in seasnakes (due to a prominent ventral keel); amphibious species (sea kraits) exhibit an intermediate shape. The tail of amphibious and marine species (a major propulsive structure during swimming) is higher and thinner than in terrestrial snakes (i.e., paddle-shaped) but shorter relative to body length. The evolution of a laterally compressed shape has been achieved by an increase in body height rather than a decrease in body width, possibly reflecting selection for more effective propulsive thrust, and for an ability to maintain hydrodynamic efficiency despite the minor bodily distension inevitably caused by prey items and developing offspring.

  9. Adaptive resolution simulation of oligonucleotides

    NASA Astrophysics Data System (ADS)

    Netz, Paulo A.; Potestio, Raffaello; Kremer, Kurt

    2016-12-01

    Nucleic acids are characterized by a complex hierarchical structure and a variety of interaction mechanisms with other molecules. These features suggest the need of multiscale simulation methods in order to grasp the relevant physical properties of deoxyribonucleic acid (DNA) and RNA using in silico experiments. Here we report an implementation of a dual-resolution modeling of a DNA oligonucleotide in physiological conditions; in the presented setup only the nucleotide molecule and the solvent and ions in its proximity are described at the atomistic level; in contrast, the water molecules and ions far from the DNA are represented as computationally less expensive coarse-grained particles. Through the analysis of several structural and dynamical parameters, we show that this setup reliably reproduces the physical properties of the DNA molecule as observed in reference atomistic simulations. These results represent a first step towards a realistic multiscale modeling of nucleic acids and provide a quantitatively solid ground for their simulation using dual-resolution methods.

  10. Adaptive resolution simulation of oligonucleotides.

    PubMed

    Netz, Paulo A; Potestio, Raffaello; Kremer, Kurt

    2016-12-21

    Nucleic acids are characterized by a complex hierarchical structure and a variety of interaction mechanisms with other molecules. These features suggest the need of multiscale simulation methods in order to grasp the relevant physical properties of deoxyribonucleic acid (DNA) and RNA using in silico experiments. Here we report an implementation of a dual-resolution modeling of a DNA oligonucleotide in physiological conditions; in the presented setup only the nucleotide molecule and the solvent and ions in its proximity are described at the atomistic level; in contrast, the water molecules and ions far from the DNA are represented as computationally less expensive coarse-grained particles. Through the analysis of several structural and dynamical parameters, we show that this setup reliably reproduces the physical properties of the DNA molecule as observed in reference atomistic simulations. These results represent a first step towards a realistic multiscale modeling of nucleic acids and provide a quantitatively solid ground for their simulation using dual-resolution methods.

  11. Electronic Quality of Life Assessment Using Computer-Adaptive Testing

    PubMed Central

    2016-01-01

    Background Quality of life (QoL) questionnaires are desirable for clinical practice but can be time-consuming to administer and interpret, making their widespread adoption difficult. Objective Our aim was to assess the performance of the World Health Organization Quality of Life (WHOQOL)-100 questionnaire as four item banks to facilitate adaptive testing using simulated computer adaptive tests (CATs) for physical, psychological, social, and environmental QoL. Methods We used data from the UK WHOQOL-100 questionnaire (N=320) to calibrate item banks using item response theory, which included psychometric assessments of differential item functioning, local dependency, unidimensionality, and reliability. We simulated CATs to assess the number of items administered before prespecified levels of reliability was met. Results The item banks (40 items) all displayed good model fit (P>.01) and were unidimensional (fewer than 5% of t tests significant), reliable (Person Separation Index>.70), and free from differential item functioning (no significant analysis of variance interaction) or local dependency (residual correlations < +.20). When matched for reliability, the item banks were between 45% and 75% shorter than paper-based WHOQOL measures. Across the four domains, a high standard of reliability (alpha>.90) could be gained with a median of 9 items. Conclusions Using CAT, simulated assessments were as reliable as paper-based forms of the WHOQOL with a fraction of the number of items. These properties suggest that these item banks are suitable for computerized adaptive assessment. These item banks have the potential for international development using existing alternative language versions of the WHOQOL items. PMID:27694100

  12. Early cardiovascular adaptation to simulated zero gravity

    NASA Technical Reports Server (NTRS)

    Nixon, J. V.; Murray, R. G.; Bryant, C.; Johnson, R. L., Jr.; Mitchell, J. H.; Holland, O. B.; Gomez-Sanchez, C.; Vergne-Marini, P.; Blomqvist, C. G.

    1979-01-01

    A study was conducted on five normal male volunteers (23-29 yr), under controlled conditions, to evaluate early adaptive responses to zero gravity. Specific objectives are (1) to characterize the hemodynamic, renal and hormonal responses to a central fluid shift, and (2) to compare data obtained during and after head-down tilt with corresponding data from actual space flight to validate tilt as a physiological model for simulation of zero gravity. Zero gravity is simulated by a 24-hr period of head-down tilt at 5 deg. The results suggest that hemodynamic adaptation occurs rapidly and is essentially accomplished by 6 hr, and that adaptation includes diuresis and reduction in blood volume. The validity of head-down tilt at 5 deg as an experimental model is established by comparing the results obtained with data from Apollo and Skylab astronauts on body fluid distributions and postflight responses to orthostatic and exercise stress.

  13. Distributed adaptive simulation through standards-based integration of simulators and adaptive learning systems.

    PubMed

    Bergeron, Bryan; Cline, Andrew; Shipley, Jaime

    2012-01-01

    We have developed a distributed, standards-based architecture that enables simulation and simulator designers to leverage adaptive learning systems. Our approach, which incorporates an electronic competency record, open source LMS, and open source microcontroller hardware, is a low-cost, pragmatic option to integrating simulators with traditional courseware.

  14. Stressful Life Events: Measurement, Moderators, and Adaptation.

    DTIC Science & Technology

    1980-10-10

    tolerance for stimulation, sensation seeking as a personality attribute may well serve as an important moderator of life stress. High sensation seekers...experiencing stressful life events and psychological well -being. A helping spouse seems to be particularly valuable in contributing to self- confidence...7. Crnic, K. A., Greenberg, M. T., Ragozin, A. S., & Robinson, N. M. The effects of life stress and social support on the life satisfaction and

  15. Coordinated adaptive washout for motion simulators.

    NASA Technical Reports Server (NTRS)

    Parrish, R. V.; Dieudonne, J. E.; Bowles, R. L.; Martin, D. J., Jr.

    1973-01-01

    This paper introduces a new method of providing motion cues to a moving base six-degree-of-freedom flight simulator utilizing nonlinear filters. Coordinated adaptive filters, used to coordinate translational and rotational motion, are derived based on the method of continuous steepest descent, and the basic concept of the digital controllers used for the uncoordinated heave and yaw cues is also presented. The coordinated adaptive washout method is illustrated by an application in a six-degree-of-freedom fixed-base environment.

  16. Adaptability and Life Satisfaction: The Moderating Role of Social Support

    PubMed Central

    Zhou, Mi; Lin, Weipeng

    2016-01-01

    The purpose of this study was to investigate the moderating role of social support in the relationship between adaptability and life satisfaction. Data were collected from 99 undergraduate freshmen in a Chinese university using a lagged design with a 1-month interval. Results demonstrated that social support moderated the relation between adaptability and life satisfaction, such that the positive relation between adaptability and life satisfaction was stronger for individuals with higher levels of social support than for individuals with lower levels of social support. The theoretical and practical implications of this result are discussed. PMID:27516753

  17. Adaptability and Life Satisfaction: The Moderating Role of Social Support.

    PubMed

    Zhou, Mi; Lin, Weipeng

    2016-01-01

    The purpose of this study was to investigate the moderating role of social support in the relationship between adaptability and life satisfaction. Data were collected from 99 undergraduate freshmen in a Chinese university using a lagged design with a 1-month interval. Results demonstrated that social support moderated the relation between adaptability and life satisfaction, such that the positive relation between adaptability and life satisfaction was stronger for individuals with higher levels of social support than for individuals with lower levels of social support. The theoretical and practical implications of this result are discussed.

  18. Adaptive Vlasov Simulations of Intense Beams

    SciTech Connect

    Sonnendruecker, Eric; Gutnic, Michael; Haefele, Matthieu; Lemaire, Jean-Louis

    2005-06-08

    Most simulations of intense particle beams are performed nowadays using Particle In Cell (PIC) techniques. Direct grid based Vlasov methods have also been used but mostly for 1D simulations as they become very costly in higher dimensions when using uniform phase space grids. We have recently introduced adaptive mesh refinement techniques that allow us to automatically concentrate the grid points at places where the distribution function is varying most. In this paper we shall introduce this technique and show how it can be used to improve the efficiency of grid based Vlasov solvers.

  19. Adaptive resolution simulation of salt solutions

    NASA Astrophysics Data System (ADS)

    Bevc, Staš; Junghans, Christoph; Kremer, Kurt; Praprotnik, Matej

    2013-10-01

    We present an adaptive resolution simulation of aqueous salt (NaCl) solutions at ambient conditions using the adaptive resolution scheme. Our multiscale approach concurrently couples the atomistic and coarse-grained models of the aqueous NaCl, where water molecules and ions change their resolution while moving from one resolution domain to the other. We employ standard extended simple point charge (SPC/E) and simple point charge (SPC) water models in combination with AMBER and GROMOS force fields for ion interactions in the atomistic domain. Electrostatics in our model are described by the generalized reaction field method. The effective interactions for water-water and water-ion interactions in the coarse-grained model are derived using structure-based coarse-graining approach while the Coulomb interactions between ions are appropriately screened. To ensure an even distribution of water molecules and ions across the simulation box we employ thermodynamic forces. We demonstrate that the equilibrium structural, e.g. radial distribution functions and density distributions of all the species, and dynamical properties are correctly reproduced by our adaptive resolution method. Our multiscale approach, which is general and can be used for any classical non-polarizable force-field and/or types of ions, will significantly speed up biomolecular simulation involving aqueous salt.

  20. Adaptive System Modeling for Spacecraft Simulation

    NASA Technical Reports Server (NTRS)

    Thomas, Justin

    2011-01-01

    This invention introduces a methodology and associated software tools for automatically learning spacecraft system models without any assumptions regarding system behavior. Data stream mining techniques were used to learn models for critical portions of the International Space Station (ISS) Electrical Power System (EPS). Evaluation on historical ISS telemetry data shows that adaptive system modeling reduces simulation error anywhere from 50 to 90 percent over existing approaches. The purpose of the methodology is to outline how someone can create accurate system models from sensor (telemetry) data. The purpose of the software is to support the methodology. The software provides analysis tools to design the adaptive models. The software also provides the algorithms to initially build system models and continuously update them from the latest streaming sensor data. The main strengths are as follows: Creates accurate spacecraft system models without in-depth system knowledge or any assumptions about system behavior. Automatically updates/calibrates system models using the latest streaming sensor data. Creates device specific models that capture the exact behavior of devices of the same type. Adapts to evolving systems. Can reduce computational complexity (faster simulations).

  1. Simulation of DKIST solar adaptive optics system

    NASA Astrophysics Data System (ADS)

    Marino, Jose; Carlisle, Elizabeth; Schmidt, Dirk

    2016-07-01

    Solar adaptive optics (AO) simulations are a valuable tool to guide the design and optimization process of current and future solar AO and multi-conjugate AO (MCAO) systems. Solar AO and MCAO systems rely on extended object cross-correlating Shack-Hartmann wavefront sensors to measure the wavefront. Accurate solar AO simulations require computationally intensive operations, which have until recently presented a prohibitive computational cost. We present an update on the status of a solar AO and MCAO simulation tool being developed at the National Solar Observatory. The simulation tool is a multi-threaded application written in the C++ language that takes advantage of current large multi-core CPU computer systems and fast ethernet connections to provide accurate full simulation of solar AO and MCAO systems. It interfaces with KAOS, a state of the art solar AO control software developed by the Kiepenheuer-Institut fuer Sonnenphysik, that provides reliable AO control. We report on the latest results produced by the solar AO simulation tool.

  2. Life sciences laboratory breadboard simulations for shuttle

    NASA Technical Reports Server (NTRS)

    Taketa, S. T.; Simmonds, R. C.; Callahan, P. X.

    1975-01-01

    Breadboard simulations of life sciences laboratory concepts for conducting bioresearch in space were undertaken as part of the concept verification testing program. Breadboard simulations were conducted to test concepts of and scope problems associated with bioresearch support equipment and facility requirements and their operational integration for conducting manned research in earth orbital missions. It emphasized requirements, functions, and procedures for candidate research on crew members (simulated) and subhuman primates and on typical radioisotope studies in rats, a rooster, and plants.

  3. Adaptive wavelet simulation of global ocean dynamics

    NASA Astrophysics Data System (ADS)

    Kevlahan, N. K.-R.; Dubos, T.; Aechtner, M.

    2015-07-01

    In order to easily enforce solid-wall boundary conditions in the presence of complex coastlines, we propose a new mass and energy conserving Brinkman penalization for the rotating shallow water equations. This penalization does not lead to higher wave speeds in the solid region. The error estimates for the penalization are derived analytically and verified numerically for linearized one dimensional equations. The penalization is implemented in a conservative dynamically adaptive wavelet method for the rotating shallow water equations on the sphere with bathymetry and coastline data from NOAA's ETOPO1 database. This code could form the dynamical core for a future global ocean model. The potential of the dynamically adaptive ocean model is illustrated by using it to simulate the 2004 Indonesian tsunami and wind-driven gyres.

  4. Hybrid adaptive-optics visual simulator.

    PubMed

    Cánovas, Carmen; Prieto, Pedro M; Manzanera, Silvestre; Mira, Alejandro; Artal, Pablo

    2010-01-15

    We have developed a hybrid adaptive-optics visual simulator (HAOVS), combining two different phase-manipulation technologies: an optically addressed liquid-crystal phase modulator, relatively slow but capable of producing abrupt or discontinuous phase profiles; and a membrane deformable mirror, restricted to smooth profiles but with a temporal response allowing compensation of the eye's aberration fluctuations. As proof of concept, a phase element structured as discontinuous radial sectors was objectively tested as a function of defocus, and a correction loop was closed in a real eye. To further illustrate the capabilities of the device for visual simulation, we recorded extended images of different stimuli through the system by means of an external camera replacing the subject's eye. The HAOVS is specially intended as a tool for developing new ophthalmic optics elements, where it opens the possibility to explore designs with irregularities and/or discontinuities.

  5. Simulating Astronomical Adaptive Optics Systems Using Yao

    NASA Astrophysics Data System (ADS)

    Rigaut, François; Van Dam, Marcos

    2013-12-01

    Adaptive Optics systems are at the heart of the coming Extremely Large Telescopes generation. Given the importance, complexity and required advances of these systems, being able to simulate them faithfully is key to their success, and thus to the success of the ELTs. The type of systems envisioned to be built for the ELTs cover most of the AO breeds, from NGS AO to multiple guide star Ground Layer, Laser Tomography and Multi-Conjugate AO systems, with typically a few thousand actuators. This represents a large step up from the current generation of AO systems, and accordingly a challenge for existing AO simulation packages. This is especially true as, in the past years, computer power has not been following Moore's law in its most common understanding; CPU clocks are hovering at about 3GHz. Although the use of super computers is a possible solution to run these simulations, being able to use smaller machines has obvious advantages: cost, access, environmental issues. By using optimised code in an already proven AO simulation platform, we were able to run complex ELT AO simulations on very modest machines, including laptops. The platform is YAO. In this paper, we describe YAO, its architecture, its capabilities, the ELT-specific challenges and optimisations, and finally its performance. As an example, execution speed ranges from 5 iterations per second for a 6 LGS 60x60 subapertures Shack-Hartmann Wavefront sensor Laser Tomography AO system (including full physical image formation and detector characteristics) up to over 30 iterations/s for a single NGS AO system.

  6. How Simulation/Gaming Transformed My Life

    ERIC Educational Resources Information Center

    Ellington, Henry

    2012-01-01

    In this invited autobiography, the author describes the impact that educational gaming and simulation has had on his professional career. He begins by reviewing his early life and education in Aberdeen and his subsequent work as a research scientist, schoolteacher, and physics lecturer. He then shows how he changed disciplines from physics to…

  7. Adaptive resolution simulation in equilibrium and beyond

    NASA Astrophysics Data System (ADS)

    Wang, H.; Agarwal, A.

    2015-09-01

    In this paper, we investigate the equilibrium statistical properties of both the force and potential interpolations of adaptive resolution simulation (AdResS) under the theoretical framework of grand-canonical like AdResS (GC-AdResS). The thermodynamic relations between the higher and lower resolutions are derived by considering the absence of fundamental conservation laws in mechanics for both branches of AdResS. In order to investigate the applicability of AdResS method in studying the properties beyond the equilibrium, we demonstrate the accuracy of AdResS in computing the dynamical properties in two numerical examples: The velocity auto-correlation of pure water and the conformational relaxation of alanine dipeptide dissolved in water. Theoretical and technical open questions of the AdResS method are discussed in the end of the paper.

  8. Boolean network simulations for life scientists.

    PubMed

    Albert, István; Thakar, Juilee; Li, Song; Zhang, Ranran; Albert, Réka

    2008-11-14

    Modern life sciences research increasingly relies on computational solutions, from large scale data analyses to theoretical modeling. Within the theoretical models Boolean networks occupy an increasing role as they are eminently suited at mapping biological observations and hypotheses into a mathematical formalism. The conceptual underpinnings of Boolean modeling are very accessible even without a background in quantitative sciences, yet it allows life scientists to describe and explore a wide range of surprisingly complex phenomena. In this paper we provide a clear overview of the concepts used in Boolean simulations, present a software library that can perform these simulations based on simple text inputs and give three case studies. The large scale simulations in these case studies demonstrate the Boolean paradigms and their applicability as well as the advanced features and complex use cases that our software package allows. Our software is distributed via a liberal Open Source license and is freely accessible from http://booleannet.googlecode.com.

  9. Simulation of Biochemical Pathway Adaptability Using Evolutionary Algorithms

    SciTech Connect

    Bosl, W J

    2005-01-26

    The systems approach to genomics seeks quantitative and predictive descriptions of cells and organisms. However, both the theoretical and experimental methods necessary for such studies still need to be developed. We are far from understanding even the simplest collective behavior of biomolecules, cells or organisms. A key aspect to all biological problems, including environmental microbiology, evolution of infectious diseases, and the adaptation of cancer cells is the evolvability of genomes. This is particularly important for Genomes to Life missions, which tend to focus on the prospect of engineering microorganisms to achieve desired goals in environmental remediation and climate change mitigation, and energy production. All of these will require quantitative tools for understanding the evolvability of organisms. Laboratory biodefense goals will need quantitative tools for predicting complicated host-pathogen interactions and finding counter-measures. In this project, we seek to develop methods to simulate how external and internal signals cause the genetic apparatus to adapt and organize to produce complex biochemical systems to achieve survival. This project is specifically directed toward building a computational methodology for simulating the adaptability of genomes. This project investigated the feasibility of using a novel quantitative approach to studying the adaptability of genomes and biochemical pathways. This effort was intended to be the preliminary part of a larger, long-term effort between key leaders in computational and systems biology at Harvard University and LLNL, with Dr. Bosl as the lead PI. Scientific goals for the long-term project include the development and testing of new hypotheses to explain the observed adaptability of yeast biochemical pathways when the myosin-II gene is deleted and the development of a novel data-driven evolutionary computation as a way to connect exploratory computational simulation with hypothesis

  10. Adaptive prolonged postreproductive life span in killer whales.

    PubMed

    Foster, Emma A; Franks, Daniel W; Mazzi, Sonia; Darden, Safi K; Balcomb, Ken C; Ford, John K B; Croft, Darren P

    2012-09-14

    Prolonged life after reproduction is difficult to explain evolutionarily unless it arises as a physiological side effect of increased longevity or it benefits related individuals (i.e., increases inclusive fitness). There is little evidence that postreproductive life spans are adaptive in nonhuman animals. By using multigenerational records for two killer whale (Orcinus orca) populations in which females can live for decades after their final parturition, we show that postreproductive mothers increase the survival of offspring, particularly their older male offspring. This finding may explain why female killer whales have evolved the longest postreproductive life span of all nonhuman animals.

  11. [Real life simulations to train nurses].

    PubMed

    Alonso Felpete, Alberto Jesús; Abajas Bustillo, Rebeca; De la Horra Gutiérrez, Inmaculada; Hoz Cuerno, Verónica; Llata Agüero, Gema; López López, Luis Mariano; Sánchez Herrán, Beatriz

    2004-01-01

    Nurses must confront critical potential life threatening situations daily. These are very tense situations which must be solved in a rapid, adequate manner in coordination with the rest of the professional health team. How to deal with these crises, which usually follow an established protocol, must be learned and practiced in a safe environment which provides the greatest possible guarantee of success. The best way to acquire this knowledge and skill is through a real life simulation. Nurses from various disciplines carry out their work in the Training Center for Critical Crises at the Marqués de Valdecilla University Hospital in Santander, the only center in Spain which runs this type of simulation. In 2003, this center initiated a specific training simulation for nurses whose purpose is to increase scientific-technical knowledge to the maximum and accelerate the learning of non-technical social and cognitive fundamentals within the working environment of a professional health team. The following article describes a simulation meeting these characteristics, its teaching methods, advantages, importance for professional health teams, and its repercussions on patients.

  12. Career Adaptability: An Integrative Construct for Life-Span, Life-Space Theory.

    ERIC Educational Resources Information Center

    Savickas, Mark L.

    1997-01-01

    Examines the origin and current status of lifespan, life-space theory and proposes one way in which to integrate its three segments. Discusses a functionalist strategy for theory construction and the outcomes and consequences of this strategy. Discusses future directions for theory development, such as career adaptability and planful attitudes.…

  13. Adaptive midlife defense mechanisms and late-life health.

    PubMed

    Malone, Johanna C; Cohen, Shiri; Liu, Sabrina R; Vaillant, George E; Waldinger, Robert J

    2013-07-01

    A growing body of research suggests that personality characteristics relate to physical health; however, this relation ship has primarily been tested in cross-sectional studies that have not followed the participants into old age. The present study utilizes data from a 70-year longitudinal study to prospectively examine the relationship between the adaptive defense mechanisms in midlife and objectively assessed physical health in late life. In addition to examining the direct effect, we test whether social support mediates this relation ship. The sample consisted of 90 men who were followed for over seven decades beginning in late adolescence. Health ratings from medical records were made at three time points (ages 70, 75, and 80). Defense mechanisms were coded from narratives by trained independent raters (Vaillant, Bond, & Vaillant, 1986). Independent raters assessed social supports between ages 50 and 70. More adaptive defenses in midlife were associated with better physical health at all three time points in late life. These relationships were partially mediated by social support. Findings are consistent with the theory that defense maturity is important for building social relationships, which in turn contribute to better late-life physical health. Psychological interventions aimed at improving these domains may be beneficial for physical health.

  14. Procedure for Adapting Direct Simulation Monte Carlo Meshes

    NASA Technical Reports Server (NTRS)

    Woronowicz, Michael S.; Wilmoth, Richard G.; Carlson, Ann B.; Rault, Didier F. G.

    1992-01-01

    A technique is presented for adapting computational meshes used in the G2 version of the direct simulation Monte Carlo method. The physical ideas underlying the technique are discussed, and adaptation formulas are developed for use on solutions generated from an initial mesh. The effect of statistical scatter on adaptation is addressed, and results demonstrate the ability of this technique to achieve more accurate results without increasing necessary computational resources.

  15. Case Studies in Computer Adaptive Test Design through Simulation.

    ERIC Educational Resources Information Center

    Eignor, Daniel R.; And Others

    The extensive computer simulation work done in developing the computer adaptive versions of the Graduate Record Examinations (GRE) Board General Test and the College Board Admissions Testing Program (ATP) Scholastic Aptitude Test (SAT) is described in this report. Both the GRE General and SAT computer adaptive tests (CATs), which are fixed length…

  16. Neuromuscular adaptation to actual and simulated weightlessness

    NASA Technical Reports Server (NTRS)

    Edgerton, V. R.; Roy, R. R.

    1994-01-01

    The chronic "unloading" of the neuromuscular system during spaceflight has detrimental functional and morphological effects. Changes in the metabolic and mechanical properties of the musculature can be attributed largely to the loss of muscle protein and the alteration in the relative proportion of the proteins in skeletal muscle, particularly in the muscles that have an antigravity function under normal loading conditions. These adaptations could result in decrements in the performance of routine or specialized motor tasks, both of which may be critical for survival in an altered gravitational field, i.e., during spaceflight and during return to 1 G. For example, the loss in extensor muscle mass requires a higher percentage of recruitment of the motor pools for any specific motor task. Thus, a faster rate of fatigue will occur in the activated muscles. These consequences emphasize the importance of developing techniques for minimizing muscle loss during spaceflight, at least in preparation for the return to 1 G after spaceflight. New insights into the complexity and the interactive elements that contribute to the neuromuscular adaptations to space have been gained from studies of the role of exercise and/or growth factors as countermeasures of atrophy. The present chapter illustrates the inevitable interactive effects of neural and muscular systems in adapting to space. It also describes the considerable progress that has been made toward the goal of minimizing the functional impact of the stimuli that induce the neuromuscular adaptations to space.

  17. Investigating Validity Evidence of the Satisfaction with Life Scale Adapted for Children

    ERIC Educational Resources Information Center

    Gadermann, Anne M.; Schonert-Reichl, Kimberly A.; Zumbo, Bruno D.

    2010-01-01

    This study introduces the Satisfaction with Life Scale adapted for Children (SWLS-C) and presents psychometric findings regarding its validation. The SWLS-C was adapted from the Satisfaction with Life Scale (SWLS; Diener et al. 1985), which is one of the most commonly used measures to assess satisfaction with life in adults. Three subject matter…

  18. Mitigating Simulator Adaptation Syndrome by means of tactile stimulation.

    PubMed

    Gálvez-García, Germán; Albayay, Javier; Rehbein, Lucio; Tornay, Francisco

    2017-01-01

    Some drivers experience Simulator Adaptation Syndrome (SAS), a condition in which nausea, disorientation, dizziness, headache, and difficulty focusing, are exhibited when driving in a simulator. To reduce this syndrome, we investigated the efficacy of tactile stimulation (TS) on mitigating Simulator Adaptation Syndrome (SAS) in a driving simulation. Fifteen drivers (eight women; mean age = 24.07 years) participated in this experiment. We compared the total scores of the Simulator Sickness Questionnaire (SSQ) across two stimulation conditions (TS condition and no stimulation condition as a baseline measure). The experimental outcomes revealed that TS seemed to decrease SAS due to attentional distraction from the symptoms and not because of an improvement in balance ability.

  19. Adaptive LES Methodology for Turbulent Flow Simulations

    SciTech Connect

    Oleg V. Vasilyev

    2008-06-12

    Although turbulent flows are common in the world around us, a solution to the fundamental equations that govern turbulence still eludes the scientific community. Turbulence has often been called one of the last unsolved problem in classical physics, yet it is clear that the need to accurately predict the effect of turbulent flows impacts virtually every field of science and engineering. As an example, a critical step in making modern computational tools useful in designing aircraft is to be able to accurately predict the lift, drag, and other aerodynamic characteristics in numerical simulations in a reasonable amount of time. Simulations that take months to years to complete are much less useful to the design cycle. Much work has been done toward this goal (Lee-Rausch et al. 2003, Jameson 2003) and as cost effective accurate tools for simulating turbulent flows evolve, we will all benefit from new scientific and engineering breakthroughs. The problem of simulating high Reynolds number (Re) turbulent flows of engineering and scientific interest would have been solved with the advent of Direct Numerical Simulation (DNS) techniques if unlimited computing power, memory, and time could be applied to each particular problem. Yet, given the current and near future computational resources that exist and a reasonable limit on the amount of time an engineer or scientist can wait for a result, the DNS technique will not be useful for more than 'unit' problems for the foreseeable future (Moin & Kim 1997, Jimenez & Moin 1991). The high computational cost for the DNS of three dimensional turbulent flows results from the fact that they have eddies of significant energy in a range of scales from the characteristic length scale of the flow all the way down to the Kolmogorov length scale. The actual cost of doing a three dimensional DNS scales as Re{sup 9/4} due to the large disparity in scales that need to be fully resolved. State-of-the-art DNS calculations of isotropic turbulence

  20. Adaptive Mesh and Algorithm Refinement Using Direct Simulation Monte Carlo

    NASA Astrophysics Data System (ADS)

    Garcia, Alejandro L.; Bell, John B.; Crutchfield, William Y.; Alder, Berni J.

    1999-09-01

    Adaptive mesh and algorithm refinement (AMAR) embeds a particle method within a continuum method at the finest level of an adaptive mesh refinement (AMR) hierarchy. The coupling between the particle region and the overlaying continuum grid is algorithmically equivalent to that between the fine and coarse levels of AMR. Direct simulation Monte Carlo (DSMC) is used as the particle algorithm embedded within a Godunov-type compressible Navier-Stokes solver. Several examples are presented and compared with purely continuum calculations.

  1. Adaptive mesh fluid simulations on GPU

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Abel, Tom; Kaehler, Ralf

    2010-10-01

    We describe an implementation of compressible inviscid fluid solvers with block-structured adaptive mesh refinement on Graphics Processing Units using NVIDIA's CUDA. We show that a class of high resolution shock capturing schemes can be mapped naturally on this architecture. Using the method of lines approach with the second order total variation diminishing Runge-Kutta time integration scheme, piecewise linear reconstruction, and a Harten-Lax-van Leer Riemann solver, we achieve an overall speedup of approximately 10 times faster execution on one graphics card as compared to a single core on the host computer. We attain this speedup in uniform grid runs as well as in problems with deep AMR hierarchies. Our framework can readily be applied to more general systems of conservation laws and extended to higher order shock capturing schemes. This is shown directly by an implementation of a magneto-hydrodynamic solver and comparing its performance to the pure hydrodynamic case. Finally, we also combined our CUDA parallel scheme with MPI to make the code run on GPU clusters. Close to ideal speedup is observed on up to four GPUs.

  2. Adaptive time steps in trajectory surface hopping simulations

    NASA Astrophysics Data System (ADS)

    Spörkel, Lasse; Thiel, Walter

    2016-05-01

    Trajectory surface hopping (TSH) simulations are often performed in combination with active-space multi-reference configuration interaction (MRCI) treatments. Technical problems may arise in such simulations if active and inactive orbitals strongly mix and switch in some particular regions. We propose to use adaptive time steps when such regions are encountered in TSH simulations. For this purpose, we present a computational protocol that is easy to implement and increases the computational effort only in the critical regions. We test this procedure through TSH simulations of a GFP chromophore model (OHBI) and a light-driven rotary molecular motor (F-NAIBP) on semiempirical MRCI potential energy surfaces, by comparing the results from simulations with adaptive time steps to analogous ones with constant time steps. For both test molecules, the number of successful trajectories without technical failures rises significantly, from 53% to 95% for OHBI and from 25% to 96% for F-NAIBP. The computed excited-state lifetime remains essentially the same for OHBI and increases somewhat for F-NAIBP, and there is almost no change in the computed quantum efficiency for internal rotation in F-NAIBP. We recommend the general use of adaptive time steps in TSH simulations with active-space CI methods because this will help to avoid technical problems, increase the overall efficiency and robustness of the simulations, and allow for a more complete sampling.

  3. Towards adaptive kinetic-fluid simulations of weakly ionized plasmas

    NASA Astrophysics Data System (ADS)

    Kolobov, V. I.; Arslanbekov, R. R.

    2012-02-01

    This paper describes an Adaptive Mesh and Algorithm Refinement (AMAR) methodology for multi-scale simulations of gas flows and the challenges associated with extending this methodology for simulations of weakly ionized plasmas. The AMAR method combines Adaptive Mesh Refinement (AMR) with automatic selection of kinetic or continuum solvers in different parts of computational domains. We first review the discrete velocity method for solving Boltzmann and Wang Chang-Uhlenbeck kinetic equations for rarefied gases. Then, peculiarities of AMR implementation with octree Cartesian mesh are discussed. A Unified Flow Solver (UFS) uses AMAR method with adaptive Cartesian mesh to dynamically introduce kinetic patches for multi-scale simulations of gas flows. We describe fluid plasma models with AMR capabilities and illustrate how physical models affect simulation results for gas discharges, especially in the areas where electron kinetics plays an important role. We introduce Eulerian solvers for plasma kinetic equations and illustrate the concept of adaptive mesh in velocity space. Specifics of electron kinetics in collisional plasmas are described focusing on deterministic methods of solving kinetic equations for electrons under different conditions. We illustrate the appearance of distinct groups of electrons in the cathode region of DC discharges and discuss the physical models appropriate for each group. These kinetic models are currently being incorporated into AMAR methodology for multi-scale plasma simulations.

  4. SimulCAT: Windows Software for Simulating Computerized Adaptive Test Administration

    ERIC Educational Resources Information Center

    Han, Kyung T.

    2012-01-01

    Most, if not all, computerized adaptive testing (CAT) programs use simulation techniques to develop and evaluate CAT program administration and operations, but such simulation tools are rarely available to the public. Up to now, several software tools have been available to conduct CAT simulations for research purposes; however, these existing…

  5. A First Life with Computerized Business Simulations

    ERIC Educational Resources Information Center

    Thavikulwat, Precha

    2011-01-01

    The author discusses the theoretical lens, origins, and environment of his work on computerized business simulations. Key ideas that inform his work include the two dimensions (control and interaction) of computerized simulation, the two ways of representing a natural process (phenotypical and genotypical) in a simulation, which he defines as a…

  6. Mechanical Simulation of a Half-Life

    ERIC Educational Resources Information Center

    Grove, T. T.; Masters, M. F.

    2008-01-01

    The exponential function model of radioactive decay and the concept of a half-life are used in nuclear experiments that appear in introductory and intermediate laboratories. In our interactions with students, we have found that students at all levels have significant confusion about both the term exponential and what is meant by a half-life as…

  7. Remaining useful life prediction for an adaptive skew-Wiener process model

    NASA Astrophysics Data System (ADS)

    Huang, Zeyi; Xu, Zhengguo; Ke, Xiaojie; Wang, Wenhai; Sun, Youxian

    2017-03-01

    Predicting the remaining useful life for operational devices plays a critical role in prognostics and health management. As the models based on the stochastic processes are widely used for characterizing the degradation trajectory, an adaptive skew-Wiener model, which is much more flexible than traditional stochastic process models, is proposed to model the degradation drift of industrial devices. To make full use of the prior knowledge and the historical information, an on-line filtering algorithm is proposed for state estimation, a two-stage algorithm is adopted to estimate unknown parameters as well. For remaining useful life prediction, a novel result is presented with an explicit form based on the closed skew normal distribution. Finally, sufficient Monte Carlo simulations and an application for ball bearings in rotating electrical machines are used to validate our approach.

  8. Cross-section adjustment techniques for BWR adaptive simulation

    NASA Astrophysics Data System (ADS)

    Jessee, Matthew Anderson

    Computational capability has been developed to adjust multi-group neutron cross-sections to improve the fidelity of boiling water reactor (BWR) modeling and simulation. The method involves propagating multi-group neutron cross-section uncertainties through BWR computational models to evaluate uncertainties in key core attributes such as core k-effective, nodal power distributions, thermal margins, and in-core detector readings. Uncertainty-based inverse theory methods are then employed to adjust multi-group cross-sections to minimize the disagreement between BWR modeling predictions and measured plant data. For this work, measured plant data were virtually simulated in the form of perturbed 3-D nodal power distributions with discrepancies with predictions of the same order of magnitude as expected from plant data. Using the simulated plant data, multi-group cross-section adjustment reduces the error in core k-effective to less than 0.2% and the RMS error in nodal power to 4% (i.e. the noise level of the in-core instrumentation). To ensure that the adapted BWR model predictions are robust, Tikhonov regularization is utilized to control the magnitude of the cross-section adjustment. In contrast to few-group cross-section adjustment, which was the focus of previous research on BWR adaptive simulation, multigroup cross-section adjustment allows for future fuel cycle design optimization to include the determination of optimal fresh fuel assembly designs using the adjusted multi-group cross-sections. The major focus of this work is to efficiently propagate multi-group neutron cross-section uncertainty through BWR lattice physics calculations. Basic neutron cross-section uncertainties are provided in the form of multi-group cross-section covariance matrices. For energy groups in the resolved resonance energy range, the cross-section uncertainties are computed using an infinitely-dilute approximation of the neutron flux. In order to accurately account for spatial and

  9. Adaptive Sampling Algorithms for Probabilistic Risk Assessment of Nuclear Simulations

    SciTech Connect

    Diego Mandelli; Dan Maljovec; Bei Wang; Valerio Pascucci; Peer-Timo Bremer

    2013-09-01

    Nuclear simulations are often computationally expensive, time-consuming, and high-dimensional with respect to the number of input parameters. Thus exploring the space of all possible simulation outcomes is infeasible using finite computing resources. During simulation-based probabilistic risk analysis, it is important to discover the relationship between a potentially large number of input parameters and the output of a simulation using as few simulation trials as possible. This is a typical context for performing adaptive sampling where a few observations are obtained from the simulation, a surrogate model is built to represent the simulation space, and new samples are selected based on the model constructed. The surrogate model is then updated based on the simulation results of the sampled points. In this way, we attempt to gain the most information possible with a small number of carefully selected sampled points, limiting the number of expensive trials needed to understand features of the simulation space. We analyze the specific use case of identifying the limit surface, i.e., the boundaries in the simulation space between system failure and system success. In this study, we explore several techniques for adaptively sampling the parameter space in order to reconstruct the limit surface. We focus on several adaptive sampling schemes. First, we seek to learn a global model of the entire simulation space using prediction models or neighborhood graphs and extract the limit surface as an iso-surface of the global model. Second, we estimate the limit surface by sampling in the neighborhood of the current estimate based on topological segmentations obtained locally. Our techniques draw inspirations from topological structure known as the Morse-Smale complex. We highlight the advantages and disadvantages of using a global prediction model versus local topological view of the simulation space, comparing several different strategies for adaptive sampling in both

  10. Adaptive thinking & leadership simulation game training for special forces officers.

    SciTech Connect

    Raybourn, Elaine Marie; Mendini, Kip; Heneghan, Jerry; Deagle, Edwin

    2005-07-01

    Complex problem solving approaches and novel strategies employed by the military at the squad, team, and commander level are often best learned experimentally. Since live action exercises can be costly, advances in simulation game training technology offer exciting ways to enhance current training. Computer games provide an environment for active, critical learning. Games open up possibilities for simultaneous learning on multiple levels; players may learn from contextual information embedded in the dynamics of the game, the organic process generated by the game, and through the risks, benefits, costs, outcomes, and rewards of alternative strategies that result from decision making. In the present paper we discuss a multiplayer computer game simulation created for the Adaptive Thinking & Leadership (ATL) Program to train Special Forces Team Leaders. The ATL training simulation consists of a scripted single-player and an immersive multiplayer environment for classroom use which leverages immersive computer game technology. We define adaptive thinking as consisting of competencies such as negotiation and consensus building skills, the ability to communicate effectively, analyze ambiguous situations, be self-aware, think innovatively, and critically use effective problem solving skills. Each of these competencies is an essential element of leader development training for the U.S. Army Special Forces. The ATL simulation is used to augment experiential learning in the curriculum for the U.S. Army JFK Special Warfare Center & School (SWCS) course in Adaptive Thinking & Leadership. The school is incorporating the ATL simulation game into two additional training pipelines (PSYOPS and Civil Affairs Qualification Courses) that are also concerned with developing cultural awareness, interpersonal communication adaptability, and rapport-building skills. In the present paper, we discuss the design, development, and deployment of the training simulation, and emphasize how the

  11. Preliminary study of the space adaptation of the MELiSSA life support system

    NASA Astrophysics Data System (ADS)

    Mas-Albaigès, Joan L.; Duatis, Jordi; Podhajsky, Sandra; Guirado, Víctor; Poughon, Laurent

    MELiSSA (Micro-Ecological Life Support System Alternative) is an European Space Agency (ESA) project focused on the development of a closed regenerative life support system to aid the development of technologies for future life support systems for long term manned planetary missions, e.g. a lunar base or missions to Mars. In order to understand the potential evolution of the MELiSSA concept towards its future use in the referred manned planetary mission context the MELiSSA Space Adaptation (MSA) activity has been undertaken. MSA's main objective is to model the different MELiSSA compartments using EcosimPro R , a specialized simulation tool for life support applications, in order to define a preliminary MELiSSA implementation for service in a man-tended lunar base scenario, with a four-member crew rotating in six-month increments, and performing the basic LSS functions of air revitalization, food production, and waste and water recycling. The MELiSSA EcosimPro R Model features a dedicated library for the different MELiSSA elements (bioreactors, greenhouse, crew, interconnecting elements, etc.). It is used to dimension the MELiSSA system in terms of major parameters like mass, volume and energy needs, evaluate the accuracy of the results and define the strategy for a progressive loop closure from the initial required performance (approx.100 The MELiSSA configuration(s) obtained through the EcosimPro R simulation are further analysed using the Advanced Life Support System Evaluation (ALISSE) metric, relying on mass, energy, efficiency, human risk, system reliability and crew time, for trade-off and optimization of results. The outcome of the MSA activity is, thus, a potential Life Support System architecture description, based on combined MELiSSA and other physico-chemical technologies, defining its expected performance, associated operational conditions and logistic needs.

  12. Improving the adaptability of simulated evolutionary swarm robots in dynamically changing environments.

    PubMed

    Yao, Yao; Marchal, Kathleen; Van de Peer, Yves

    2014-01-01

    One of the important challenges in the field of evolutionary robotics is the development of systems that can adapt to a changing environment. However, the ability to adapt to unknown and fluctuating environments is not straightforward. Here, we explore the adaptive potential of simulated swarm robots that contain a genomic encoding of a bio-inspired gene regulatory network (GRN). An artificial genome is combined with a flexible agent-based system, representing the activated part of the regulatory network that transduces environmental cues into phenotypic behaviour. Using an artificial life simulation framework that mimics a dynamically changing environment, we show that separating the static from the conditionally active part of the network contributes to a better adaptive behaviour. Furthermore, in contrast with most hitherto developed ANN-based systems that need to re-optimize their complete controller network from scratch each time they are subjected to novel conditions, our system uses its genome to store GRNs whose performance was optimized under a particular environmental condition for a sufficiently long time. When subjected to a new environment, the previous condition-specific GRN might become inactivated, but remains present. This ability to store 'good behaviour' and to disconnect it from the novel rewiring that is essential under a new condition allows faster re-adaptation if any of the previously observed environmental conditions is reencountered. As we show here, applying these evolutionary-based principles leads to accelerated and improved adaptive evolution in a non-stable environment.

  13. When divergent life histories hybridize: insights into adaptive life-history traits in an annual weed.

    PubMed

    Campbell, Lesley G; Snow, Allison A; Sweeney, Patricia M

    2009-12-01

    *Colonizing weed populations face novel selective environments, which may drive rapid shifts in life history. These shifts may be amplified when colonists are hybrids of species with divergent life histories. Selection on such phenotypically diverse hybrids may create highly fecund weeds. We measured the phenotypic variation, strength of natural selection and evolutionary response of hybrid and nonhybrid weeds. *We created F(1) hybrids of wild radish, an early flowering, small-stemmed weed, and its late-flowering, large-stemmed, crop relative (Raphanus spp.). Replicate wild and hybrid populations were established in an agricultural landscape in Michigan, USA. The consequences of three generations of natural selection were measured in a common garden experiment. *Hybrid populations experienced strong selection for larger, earlier flowering plants whereas selection was relatively weak on wild populations. Large plant size evolved two to three times faster in the hybrid populations than in wild populations, yet hybrid populations did not evolve earlier flowering. Strong selection on size and phenotypic correlations between age at reproduction and size may have limited the response of flowering phenology. *Our findings demonstrate hybridization between species with divergent life histories may catalyse the rapid evolution of certain adaptive, weedy traits while tradeoffs limit the evolution of others.

  14. MADNESS: A Multiresolution, Adaptive Numerical Environment for Scientific Simulation

    SciTech Connect

    Harrison, Robert J.; Beylkin, Gregory; Bischoff, Florian A.; Calvin, Justus A.; Fann, George I.; Fosso-Tande, Jacob; Galindo, Diego; Hammond, Jeff R.; Hartman-Baker, Rebecca; Hill, Judith C.; Jia, Jun; Kottmann, Jakob S.; Yvonne Ou, M-J.; Pei, Junchen; Ratcliff, Laura E.; Reuter, Matthew G.; Richie-Halford, Adam C.; Romero, Nichols A.; Sekino, Hideo; Shelton, William A.; Sundahl, Bryan E.; Thornton, W. Scott; Valeev, Edward F.; Vázquez-Mayagoitia, Álvaro; Vence, Nicholas; Yanai, Takeshi; Yokoi, Yukina

    2016-01-01

    MADNESS (multiresolution adaptive numerical environment for scientific simulation) is a high-level software environment for solving integral and differential equations in many dimensions that uses adaptive and fast harmonic analysis methods with guaranteed precision based on multiresolution analysis and separated representations. Underpinning the numerical capabilities is a powerful petascale parallel programming environment that aims to increase both programmer productivity and code scalability. This paper describes the features and capabilities of MADNESS and briefly discusses some current applications in chemistry and several areas of physics.

  15. MADNESS: A Multiresolution, Adaptive Numerical Environment for Scientific Simulation

    SciTech Connect

    Harrison, Robert J.; Beylkin, Gregory; Bischoff, Florian A.; Calvin, Justus A.; Fann, George I.; Fosso-Tande, Jacob; Galindo, Diego; Hammond, Jeff R.; Hartman-Baker, Rebecca; Hill, Judith C.; Jia, Jun; Kottmann, Jakob S.; Yvonne Ou, M-J.; Pei, Junchen; Ratcliff, Laura E.; Reuter, Matthew G.; Richie-Halford, Adam C.; Romero, Nichols A.; Sekino, Hideo; Shelton, William A.; Sundahl, Bryan E.; Thornton, W. Scott; Valeev, Edward F.; Vázquez-Mayagoitia, Álvaro; Vence, Nicholas; Yanai, Takeshi; Yokoi, Yukina

    2016-01-01

    We present MADNESS (multiresolution adaptive numerical environment for scientific simulation) that is a high-level software environment for solving integral and differential equations in many dimensions that uses adaptive and fast harmonic analysis methods with guaranteed precision that are based on multiresolution analysis and separated representations. Underpinning the numerical capabilities is a powerful petascale parallel programming environment that aims to increase both programmer productivity and code scalability. This paper describes the features and capabilities of MADNESS and briefly discusses some current applications in chemistry and several areas of physics.

  16. Cosmological fluid mechanics with adaptively refined large eddy simulations

    NASA Astrophysics Data System (ADS)

    Schmidt, W.; Almgren, A. S.; Braun, H.; Engels, J. F.; Niemeyer, J. C.; Schulz, J.; Mekuria, R. R.; Aspden, A. J.; Bell, J. B.

    2014-06-01

    We investigate turbulence generated by cosmological structure formation by means of large eddy simulations using adaptive mesh refinement. In contrast to the widely used implicit large eddy simulations, which resolve a limited range of length-scales and treat the effect of turbulent velocity fluctuations below the grid scale solely by numerical dissipation, we apply a subgrid-scale model for the numerically unresolved fraction of the turbulence energy. For simulations with adaptive mesh refinement, we utilize a new methodology that allows us to adjust the scale-dependent energy variables in such a way that the sum of resolved and unresolved energies is globally conserved. We test our approach in simulations of randomly forced turbulence, a gravitationally bound cloud in a wind, and the Santa Barbara cluster. To treat inhomogeneous turbulence, we introduce an adaptive Kalman filtering technique that separates turbulent velocity fluctuations on resolved length-scales from the non-turbulent bulk flow. From the magnitude of the fluctuating component and the subgrid-scale turbulence energy, a total turbulent velocity dispersion of several 100 km s-1 is obtained for the Santa Barbara cluster, while the low-density gas outside the accretion shocks is nearly devoid of turbulence. The energy flux through the turbulent cascade and the dissipation rate predicted by the subgrid-scale model correspond to dynamical time-scales around 5 Gyr, independent of numerical resolution.

  17. Adaptations to polar life in mammals and birds.

    PubMed

    Blix, Arnoldus Schytte

    2016-04-15

    This Review presents a broad overview of adaptations of truly Arctic and Antarctic mammals and birds to the challenges of polar life. The polar environment may be characterized by grisly cold, scarcity of food and darkness in winter, and lush conditions and continuous light in summer. Resident animals cope with these changes by behavioural, physical and physiological means. These include responses aimed at reducing exposure, such as 'balling up', huddling and shelter building; seasonal changes in insulation by fur, plumage and blubber; and circulatory adjustments aimed at preservation of core temperature, to which end the periphery and extremities are cooled to increase insulation. Newborn altricial animals have profound tolerance to hypothermia, but depend on parental care for warmth, whereas precocial mammals are well insulated and respond to cold with non-shivering thermogenesis in brown adipose tissue, and precocial birds shiver to produce heat. Most polar animals prepare themselves for shortness of food during winter by the deposition of large amounts of fat in times of plenty during autumn. These deposits are governed by a sliding set-point for body fatness throughout winter so that they last until the sun reappears in spring. Polar animals are, like most others, primarily active during the light part of the day, but when the sun never sets in summer and darkness prevails during winter, high-latitude animals become intermittently active around the clock, allowing opportunistic feeding at all times. The importance of understanding the needs of the individuals of a species to understand the responses of populations in times of climate change is emphasized.

  18. Adaptive quantum computation in changing environments using projective simulation

    PubMed Central

    Tiersch, M.; Ganahl, E. J.; Briegel, H. J.

    2015-01-01

    Quantum information processing devices need to be robust and stable against external noise and internal imperfections to ensure correct operation. In a setting of measurement-based quantum computation, we explore how an intelligent agent endowed with a projective simulator can act as controller to adapt measurement directions to an external stray field of unknown magnitude in a fixed direction. We assess the agent’s learning behavior in static and time-varying fields and explore composition strategies in the projective simulator to improve the agent’s performance. We demonstrate the applicability by correcting for stray fields in a measurement-based algorithm for Grover’s search. Thereby, we lay out a path for adaptive controllers based on intelligent agents for quantum information tasks. PMID:26260263

  19. Response and adaptation of bone cells to simulated microgravity

    NASA Astrophysics Data System (ADS)

    Hu, Lifang; Li, Runzhi; Su, Peihong; Arfat, Yasir; Zhang, Ge; Shang, Peng; Qian, Airong

    2014-11-01

    Bone loss induced by microgravity during space flight is one of the most deleterious factors on astronaut's health and is mainly attributed to an unbalance in the process of bone remodeling. Studies from the space microgravity have demonstrated that the disruption of bone remodeling is associated with the changes of four main functional bone cells, including osteoblast, osteoclast, osteocyte, and mesenchymal stem cells. For the limited availability, expensive costs and confined experiment conditions for conducting space microgravity studies, the mechanism of bone cells response and adaptation to microgravity is still unclear. Therefore, some ground-based simulated microgravity methods have been developed to investigate the bioeffects of microgravity and the mechanisms. Here, based on our studies and others, we review how bone cells (osteoblasts, osteoclasts, osteocytes and mesenchymal stem cells) respond and adapt to simulated microgravity.

  20. Adaptive quantum computation in changing environments using projective simulation.

    PubMed

    Tiersch, M; Ganahl, E J; Briegel, H J

    2015-08-11

    Quantum information processing devices need to be robust and stable against external noise and internal imperfections to ensure correct operation. In a setting of measurement-based quantum computation, we explore how an intelligent agent endowed with a projective simulator can act as controller to adapt measurement directions to an external stray field of unknown magnitude in a fixed direction. We assess the agent's learning behavior in static and time-varying fields and explore composition strategies in the projective simulator to improve the agent's performance. We demonstrate the applicability by correcting for stray fields in a measurement-based algorithm for Grover's search. Thereby, we lay out a path for adaptive controllers based on intelligent agents for quantum information tasks.

  1. Adaptive quantum computation in changing environments using projective simulation

    NASA Astrophysics Data System (ADS)

    Tiersch, M.; Ganahl, E. J.; Briegel, H. J.

    2015-08-01

    Quantum information processing devices need to be robust and stable against external noise and internal imperfections to ensure correct operation. In a setting of measurement-based quantum computation, we explore how an intelligent agent endowed with a projective simulator can act as controller to adapt measurement directions to an external stray field of unknown magnitude in a fixed direction. We assess the agent’s learning behavior in static and time-varying fields and explore composition strategies in the projective simulator to improve the agent’s performance. We demonstrate the applicability by correcting for stray fields in a measurement-based algorithm for Grover’s search. Thereby, we lay out a path for adaptive controllers based on intelligent agents for quantum information tasks.

  2. Adaptive scapula bone remodeling computational simulation: Relevance to regenerative medicine

    NASA Astrophysics Data System (ADS)

    Sharma, Gulshan B.; Robertson, Douglas D.

    2013-07-01

    Shoulder arthroplasty success has been attributed to many factors including, bone quality, soft tissue balancing, surgeon experience, and implant design. Improved long-term success is primarily limited by glenoid implant loosening. Prosthesis design examines materials and shape and determines whether the design should withstand a lifetime of use. Finite element (FE) analyses have been extensively used to study stresses and strains produced in implants and bone. However, these static analyses only measure a moment in time and not the adaptive response to the altered environment produced by the therapeutic intervention. Computational analyses that integrate remodeling rules predict how bone will respond over time. Recent work has shown that subject-specific two- and three dimensional adaptive bone remodeling models are feasible and valid. Feasibility and validation were achieved computationally, simulating bone remodeling using an intact human scapula, initially resetting the scapular bone material properties to be uniform, numerically simulating sequential loading, and comparing the bone remodeling simulation results to the actual scapula's material properties. Three-dimensional scapula FE bone model was created using volumetric computed tomography images. Muscle and joint load and boundary conditions were applied based on values reported in the literature. Internal bone remodeling was based on element strain-energy density. Initially, all bone elements were assigned a homogeneous density. All loads were applied for 10 iterations. After every iteration, each bone element's remodeling stimulus was compared to its corresponding reference stimulus and its material properties modified. The simulation achieved convergence. At the end of the simulation the predicted and actual specimen bone apparent density were plotted and compared. Location of high and low predicted bone density was comparable to the actual specimen. High predicted bone density was greater than actual

  3. Adaptive scapula bone remodeling computational simulation: Relevance to regenerative medicine

    SciTech Connect

    Sharma, Gulshan B.; Robertson, Douglas D.

    2013-07-01

    Shoulder arthroplasty success has been attributed to many factors including, bone quality, soft tissue balancing, surgeon experience, and implant design. Improved long-term success is primarily limited by glenoid implant loosening. Prosthesis design examines materials and shape and determines whether the design should withstand a lifetime of use. Finite element (FE) analyses have been extensively used to study stresses and strains produced in implants and bone. However, these static analyses only measure a moment in time and not the adaptive response to the altered environment produced by the therapeutic intervention. Computational analyses that integrate remodeling rules predict how bone will respond over time. Recent work has shown that subject-specific two- and three dimensional adaptive bone remodeling models are feasible and valid. Feasibility and validation were achieved computationally, simulating bone remodeling using an intact human scapula, initially resetting the scapular bone material properties to be uniform, numerically simulating sequential loading, and comparing the bone remodeling simulation results to the actual scapula’s material properties. Three-dimensional scapula FE bone model was created using volumetric computed tomography images. Muscle and joint load and boundary conditions were applied based on values reported in the literature. Internal bone remodeling was based on element strain-energy density. Initially, all bone elements were assigned a homogeneous density. All loads were applied for 10 iterations. After every iteration, each bone element’s remodeling stimulus was compared to its corresponding reference stimulus and its material properties modified. The simulation achieved convergence. At the end of the simulation the predicted and actual specimen bone apparent density were plotted and compared. Location of high and low predicted bone density was comparable to the actual specimen. High predicted bone density was greater than

  4. A Cooperative Human-Adaptive Traffic Simulation (CHATS)

    NASA Technical Reports Server (NTRS)

    Phillips, Charles T.; Ballin, Mark G.

    1999-01-01

    NASA is considering the development of a Cooperative Human-Adaptive Traffic Simulation (CHATS), to examine and evaluate performance of the National Airspace System (NAS) as the aviation community moves toward free flight. CHATS will be specifically oriented toward simulating strategic decision-making by airspace users and by the service provider s traffic management personnel, within the context of different airspace and rules assumptions. It will use human teams to represent these interests and make decisions, and will rely on computer modeling and simulation to calculate the impacts of these decisions. The simulation objectives will be to examine: 1. evolution of airspace users and the service provider s strategies, through adaptation to new operational environments; 2. air carriers competitive and cooperative behavior; 3. expected benefits to airspace users and the service provider as compared to the current NAS; 4. operational limitations of free flight concepts due to congestion and safety concerns. This paper describes an operational concept for CHATS, and presents a high-level functional design which would utilize a combination of existing and new models and simulation capabilities.

  5. Advanced Dynamically Adaptive Algorithms for Stochastic Simulations on Extreme Scales

    SciTech Connect

    Xiu, Dongbin

    2016-06-21

    The focus of the project is the development of mathematical methods and high-performance com- putational tools for stochastic simulations, with a particular emphasis on computations on extreme scales. The core of the project revolves around the design of highly e cient and scalable numer- ical algorithms that can adaptively and accurately, in high dimensional spaces, resolve stochastic problems with limited smoothness, even containing discontinuities.

  6. An optimized index of human cardiovascular adaptation to simulated weightlessness

    NASA Technical Reports Server (NTRS)

    Wang, M.; Hassebrook, L.; Evans, J.; Varghese, T.; Knapp, C.

    1996-01-01

    Prolonged exposure to weightlessness is known to produce a variety of cardiovascular changes, some of which may influence the astronaut's performance during a mission. In order to find a reliable indicator of cardiovascular adaptation to weightlessness, we analyzed data from nine male subjects after a 24-hour period of normal activity and after a period of simulated weightlessness produced by two hours in a launch position followed by 20 hours of 6 degrees head-down tilt plus pharmacologically induced diuresis (furosemide). Heart rate, arterial pressure, thoracic fluid index, and radial flow were analyzed. Autoregressive spectral estimation and decomposition were used to obtain the spectral components of each variable from the subjects in the supine position during pre- and post-simulated weightlessness. We found a significant decrease in heart rate power and an increase in thoracic fluid index power in the high frequency region (0.2-0.45 Hz) and significant increases in radial flow and arterial pressure powers in the low frequency region (<0.2 Hz) in response to simulated weightlessness. However, due to the variability among subjects, any single variable appeared limited as a dependable index of cardiovascular adaptation to weightlessness. The backward elimination algorithm was then used to select the best discriminatory features from these spectral components. Fisher's linear discriminant and Bayes' quadratic discriminant were used to combine the selected features to obtain an optimal index of adaptation to simulated weightlessness. Results showed that both techniques provided improved discriminant performance over any single variable and thus have the potential for use as an index to track adaptation and prescribe countermeasures to the effects of weightlessness.

  7. Virtual Retail Simulations in Second Life

    ERIC Educational Resources Information Center

    Drake-Bridges, Erin; Strelzoff, Andrew; Sulbaran, Tulio

    2011-01-01

    This paper explores the use of simulations in virtual reality to teach students the fundamental processes behind retailing and product development. The project described involved one class of students who developed their own clothing lines of "virtual merchandise." A second class of students then "purchased" the wholesale…

  8. Adaptive resolution simulation of an atomistic protein in MARTINI water

    NASA Astrophysics Data System (ADS)

    Zavadlav, Julija; Melo, Manuel Nuno; Marrink, Siewert J.; Praprotnik, Matej

    2014-02-01

    We present an adaptive resolution simulation of protein G in multiscale water. We couple atomistic water around the protein with mesoscopic water, where four water molecules are represented with one coarse-grained bead, farther away. We circumvent the difficulties that arise from coupling to the coarse-grained model via a 4-to-1 molecule coarse-grain mapping by using bundled water models, i.e., we restrict the relative movement of water molecules that are mapped to the same coarse-grained bead employing harmonic springs. The water molecules change their resolution from four molecules to one coarse-grained particle and vice versa adaptively on-the-fly. Having performed 15 ns long molecular dynamics simulations, we observe within our error bars no differences between structural (e.g., root-mean-squared deviation and fluctuations of backbone atoms, radius of gyration, the stability of native contacts and secondary structure, and the solvent accessible surface area) and dynamical properties of the protein in the adaptive resolution approach compared to the fully atomistically solvated model. Our multiscale model is compatible with the widely used MARTINI force field and will therefore significantly enhance the scope of biomolecular simulations.

  9. Pre-Service Teachers in Second Life: Potentials of Simulations

    ERIC Educational Resources Information Center

    Teoh, Jase

    2012-01-01

    An in-depth qualitative study with nine secondary pre-service teachers from an undergraduate "Language and Literacy" class was conducted to examine the potential of simulation using Second Life (SL) in teacher education. Games and simulations were operationally defined in the broadest sense to distinguish key characteristics between…

  10. All about Animal Adaptations. Animal Life for Children. [Videotape].

    ERIC Educational Resources Information Center

    2000

    Animals change to better adapt to their environment. Over long periods of time, nature helps the animals adapt by changing their body shape and color as well as adjusting their methods of getting and eating food, defending themselves, and caring for their young. In this videotape, students learn what changes different animals go through in order…

  11. An adaptive nonlinear solution scheme for reservoir simulation

    SciTech Connect

    Lett, G.S.

    1996-12-31

    Numerical reservoir simulation involves solving large, nonlinear systems of PDE with strongly discontinuous coefficients. Because of the large demands on computer memory and CPU, most users must perform simulations on very coarse grids. The average properties of the fluids and rocks must be estimated on these grids. These coarse grid {open_quotes}effective{close_quotes} properties are costly to determine, and risky to use, since their optimal values depend on the fluid flow being simulated. Thus, they must be found by trial-and-error techniques, and the more coarse the grid, the poorer the results. This paper describes a numerical reservoir simulator which accepts fine scale properties and automatically generates multiple levels of coarse grid rock and fluid properties. The fine grid properties and the coarse grid simulation results are used to estimate discretization errors with multilevel error expansions. These expansions are local, and identify areas requiring local grid refinement. These refinements are added adoptively by the simulator, and the resulting composite grid equations are solved by a nonlinear Fast Adaptive Composite (FAC) Grid method, with a damped Newton algorithm being used on each local grid. The nonsymmetric linear system of equations resulting from Newton`s method are in turn solved by a preconditioned Conjugate Gradients-like algorithm. The scheme is demonstrated by performing fine and coarse grid simulations of several multiphase reservoirs from around the world.

  12. Spaceflight Sensorimotor Analogs: Simulating Acute and Adaptive Effects

    NASA Technical Reports Server (NTRS)

    Taylor, Laura C.; Harm, Deborah L.; Kozlovskaya, Inessa; Reschke, Millard F.; Wood, Scott J.

    2009-01-01

    Adaptive changes in sensorimotor function during spaceflight are reflected by spatial disorientation, motion sickness, gaze destabilization and decrements in balance, locomotion and eye-hand coordination that occur during and following transitions between different gravitational states. The purpose of this study was to conduct a meta-synthesis of data from spaceflight analogs to evaluate their effectiveness in simulating adaptive changes in sensorimotor function. METHODS. The analogs under review were categorized as either acute analogs used to simulate performance decrements accompanied with transient changes, or adaptive analogs used to drive sensorimotor learning to altered sensory feedback. The effectiveness of each analog was evaluated in terms of mechanisms of action, magnitude and time course of observed deficits compared to spaceflight data, and the effects of amplitude and exposure duration. RESULTS. Parabolic flight has been used extensively to examine effects of acute variation in gravitational loads, ranging from hypergravity to microgravity. More recently, galvanic vestibular stimulation has been used to elicit acute postural, locomotor and gaze dysfunction by disrupting vestibular afferents. Patient populations, e.g., with bilateral vestibular loss or cerebellar dysfunction, have been proposed to model acute sensorimotor dysfunction. Early research sponsored by NASA involved living onboard rotating rooms, which appeared to approximate the time course of adaptation and post-exposure recovery observed in astronauts following spaceflight. Exposure to different bed-rest paradigms (6 deg head down, dry immersion) result in similar motor deficits to that observed following spaceflight. Shorter adaptive analogs have incorporated virtual reality environments, visual distortion paradigms, exposure to conflicting tilt-translation cues, and exposure to 3Gx centrifugation. As with spaceflight, there is considerable variability in responses to most of the analogs

  13. Force oscillations simulating breathing maneuvers do not prevent force adaptation.

    PubMed

    Pascoe, Chris; Jiao, Yuekan; Seow, Chun Y; Paré, Peter D; Bossé, Ynuk

    2012-07-01

    Airway inflammation in patients with asthma exposes the airway smooth muscle (ASM) to a variety of spasmogens. These spasmogens increase ASM tone, which can lead to force adaptation. Length oscillations of ASM, which occur in vivo due to breathing maneuvers, can attenuate force adaptation. However, in the presence of tone, the force oscillations required to achieve these length oscillations may be unphysiologic (i.e., magnitude greater than the ones achieved due to the swings in transpulmonary pressure required for breathing). In the present study, we applied force oscillations simulating the tension oscillations experienced by the wall of a fourth-generation airway during tidal breathing with or without deep inspirations (DI) to ASM. The goal was to investigate whether force adaptation occurs in conditions mimicking breathing maneuvers. Tone was induced by carbachol (average, 20 nM), and the force-generating capacity of the ASM was assessed at 5-minute intervals before and after carbachol administration using electrical field stimulations (EFS). The results show that force oscillations applied before the introduction of tone had a small effect on the force produced by EFS (declined to 96.8% [P > 0.05] and 92.3% [P < 0.05] with and without DI, respectively). The tone induced by carbachol transiently decreased after a DI and declined significantly (P < 0.05) due to tidal breathing oscillations (25%). These force oscillations did not prevent force adaptation (gain of force of 11.2 ± 2.2 versus 13.5 ± 2.7 and 11.2 ± 3.0% in static versus dynamic conditions with or without DI, respectively). The lack of effect of simulated breathing maneuvers on force adaptation suggests that this gain in ASM force may occur in vivo and could contribute to the development of airway hyperresponsiveness.

  14. Design of a Mobile Agent-Based Adaptive Communication Middleware for Federations of Critical Infrastructure Simulations

    NASA Astrophysics Data System (ADS)

    Görbil, Gökçe; Gelenbe, Erol

    The simulation of critical infrastructures (CI) can involve the use of diverse domain specific simulators that run on geographically distant sites. These diverse simulators must then be coordinated to run concurrently in order to evaluate the performance of critical infrastructures which influence each other, especially in emergency or resource-critical situations. We therefore describe the design of an adaptive communication middleware that provides reliable and real-time one-to-one and group communications for federations of CI simulators over a wide-area network (WAN). The proposed middleware is composed of mobile agent-based peer-to-peer (P2P) overlays, called virtual networks (VNets), to enable resilient, adaptive and real-time communications over unreliable and dynamic physical networks (PNets). The autonomous software agents comprising the communication middleware monitor their performance and the underlying PNet, and dynamically adapt the P2P overlay and migrate over the PNet in order to optimize communications according to the requirements of the federation and the current conditions of the PNet. Reliable communications is provided via redundancy within the communication middleware and intelligent migration of agents over the PNet. The proposed middleware integrates security methods in order to protect the communication infrastructure against attacks and provide privacy and anonymity to the participants of the federation. Experiments with an initial version of the communication middleware over a real-life networking testbed show that promising improvements can be obtained for unicast and group communications via the agent migration capability of our middleware.

  15. A simulated force generator with an adaptive command structure

    NASA Astrophysics Data System (ADS)

    Hanes, P. Jeff

    2006-05-01

    The Force Laydown Automated Generator (FLAG) is a script-driven behavior model that automatically creates military formations from the platoon level up to division level for use in simulations built on the FLAMES simulation framework. The script allows users to define formation command structure, command relationships, vehicle type and equipment, and behaviors. We have used it to automatically generate more than 3000 units in a single simulation. Currently, FLAG is used in the Air Force Research Laboratory Munitions Directorate (AFRL/MN) to assist their Comprehensive Analysis Process (CAP). It produces a reasonable threat laydown of red forces for testing their blue concept weapons. Our success in the application of FLAG leads us to believe that it offers an invaluable potential for use in training environments and other applications that need a large number of reactive, adaptive forces - red or blue.

  16. Visualization of Octree Adaptive Mesh Refinement (AMR) in Astrophysical Simulations

    NASA Astrophysics Data System (ADS)

    Labadens, M.; Chapon, D.; Pomaréde, D.; Teyssier, R.

    2012-09-01

    Computer simulations are important in current cosmological research. Those simulations run in parallel on thousands of processors, and produce huge amount of data. Adaptive mesh refinement is used to reduce the computing cost while keeping good numerical accuracy in regions of interest. RAMSES is a cosmological code developed by the Commissariat à l'énergie atomique et aux énergies alternatives (English: Atomic Energy and Alternative Energies Commission) which uses Octree adaptive mesh refinement. Compared to grid based AMR, the Octree AMR has the advantage to fit very precisely the adaptive resolution of the grid to the local problem complexity. However, this specific octree data type need some specific software to be visualized, as generic visualization tools works on Cartesian grid data type. This is why the PYMSES software has been also developed by our team. It relies on the python scripting language to ensure a modular and easy access to explore those specific data. In order to take advantage of the High Performance Computer which runs the RAMSES simulation, it also uses MPI and multiprocessing to run some parallel code. We would like to present with more details our PYMSES software with some performance benchmarks. PYMSES has currently two visualization techniques which work directly on the AMR. The first one is a splatting technique, and the second one is a custom ray tracing technique. Both have their own advantages and drawbacks. We have also compared two parallel programming techniques with the python multiprocessing library versus the use of MPI run. The load balancing strategy has to be smartly defined in order to achieve a good speed up in our computation. Results obtained with this software are illustrated in the context of a massive, 9000-processor parallel simulation of a Milky Way-like galaxy.

  17. Predictive Simulation Generates Human Adaptations during Loaded and Inclined Walking

    PubMed Central

    Hicks, Jennifer L.; Delp, Scott L.

    2015-01-01

    Predictive simulation is a powerful approach for analyzing human locomotion. Unlike techniques that track experimental data, predictive simulations synthesize gaits by minimizing a high-level objective such as metabolic energy expenditure while satisfying task requirements like achieving a target velocity. The fidelity of predictive gait simulations has only been systematically evaluated for locomotion data on flat ground. In this study, we construct a predictive simulation framework based on energy minimization and use it to generate normal walking, along with walking with a range of carried loads and up a range of inclines. The simulation is muscle-driven and includes controllers based on muscle force and stretch reflexes and contact state of the legs. We demonstrate how human-like locomotor strategies emerge from adapting the model to a range of environmental changes. Our simulation dynamics not only show good agreement with experimental data for normal walking on flat ground (92% of joint angle trajectories and 78% of joint torque trajectories lie within 1 standard deviation of experimental data), but also reproduce many of the salient changes in joint angles, joint moments, muscle coordination, and metabolic energy expenditure observed in experimental studies of loaded and inclined walking. PMID:25830913

  18. Decentralized adaptive control of manipulators - Theory, simulation, and experimentation

    NASA Technical Reports Server (NTRS)

    Seraji, Homayoun

    1989-01-01

    The author presents a simple decentralized adaptive-control scheme for multijoint robot manipulators based on the independent joint control concept. The control objective is to achieve accurate tracking of desired joint trajectories. The proposed control scheme does not use the complex manipulator dynamic model, and each joint is controlled simply by a PID (proportional-integral-derivative) feedback controller and a position-velocity-acceleration feedforward controller, both with adjustable gains. Simulation results are given for a two-link direct-drive manipulator under adaptive independent joint control. The results illustrate trajectory tracking under coupled dynamics and varying payload. The proposed scheme is implemented on a MicroVAX II computer for motion control of the three major joints of a PUMA 560 arm. Experimental results are presented to demonstrate that trajectory tracking is achieved despite coupled nonlinear joint dynamics.

  19. Simulating local adaptation to climate of forest trees with a Physio-Demo-Genetics model

    PubMed Central

    Oddou-Muratorio, Sylvie; Davi, Hendrik

    2014-01-01

    One challenge of evolutionary ecology is to predict the rate and mechanisms of population adaptation to environmental variations. The variations in most life history traits are shaped both by individual genotypic and by environmental variation. Forest trees exhibit high levels of genetic diversity, large population sizes, and gene flow, and they also show a high level of plasticity for life history traits. We developed a new Physio-Demo-Genetics model (denoted PDG) coupling (i) a physiological module simulating individual tree responses to the environment; (ii) a demographic module simulating tree survival, reproduction, and pollen and seed dispersal; and (iii) a quantitative genetics module controlling the heritability of key life history traits. We used this model to investigate the plastic and genetic components of the variations in the timing of budburst (TBB) along an elevational gradient of Fagus sylvatica (the European beech). We used a repeated 5 years climatic sequence to show that five generations of natural selection were sufficient to develop nonmonotonic genetic differentiation in the TBB along the local climatic gradient but also that plastic variation among different elevations and years was higher than genetic variation. PDG complements theoretical models and provides testable predictions to understand the adaptive potential of tree populations. PMID:24822080

  20. Comparison of wavefront sensor models for simulation of adaptive optics.

    PubMed

    Wu, Zhiwen; Enmark, Anita; Owner-Petersen, Mette; Andersen, Torben

    2009-10-26

    The new generation of extremely large telescopes will have adaptive optics. Due to the complexity and cost of such systems, it is important to simulate their performance before construction. Most systems planned will have Shack-Hartmann wavefront sensors. Different mathematical models are available for simulation of such wavefront sensors. The choice of wavefront sensor model strongly influences computation time and simulation accuracy. We have studied the influence of three wavefront sensor models on performance calculations for a generic, adaptive optics (AO) system designed for K-band operation of a 42 m telescope. The performance of this AO system has been investigated both for reduced wavelengths and for reduced r(0) in the K band. The telescope AO system was designed for K-band operation, that is both the subaperture size and the actuator pitch were matched to a fixed value of r(0) in the K-band. We find that under certain conditions, such as investigating limiting guide star magnitude for large Strehl-ratios, a full model based on Fraunhofer propagation to the subimages is significantly more accurate. It does however require long computation times. The shortcomings of simpler models based on either direct use of average wavefront tilt over the subapertures for actuator control, or use of the average tilt to move a precalculated point spread function in the subimages are most pronounced for studies of system limitations to operating parameter variations. In the long run, efficient parallelization techniques may be developed to overcome the problem.

  1. Adaptive mesh refinement and adjoint methods in geophysics simulations

    NASA Astrophysics Data System (ADS)

    Burstedde, Carsten

    2013-04-01

    It is an ongoing challenge to increase the resolution that can be achieved by numerical geophysics simulations. This applies to considering sub-kilometer mesh spacings in global-scale mantle convection simulations as well as to using frequencies up to 1 Hz in seismic wave propagation simulations. One central issue is the numerical cost, since for three-dimensional space discretizations, possibly combined with time stepping schemes, a doubling of resolution can lead to an increase in storage requirements and run time by factors between 8 and 16. A related challenge lies in the fact that an increase in resolution also increases the dimensionality of the model space that is needed to fully parametrize the physical properties of the simulated object (a.k.a. earth). Systems that exhibit a multiscale structure in space are candidates for employing adaptive mesh refinement, which varies the resolution locally. An example that we found well suited is the mantle, where plate boundaries and fault zones require a resolution on the km scale, while deeper area can be treated with 50 or 100 km mesh spacings. This approach effectively reduces the number of computational variables by several orders of magnitude. While in this case it is possible to derive the local adaptation pattern from known physical parameters, it is often unclear what are the most suitable criteria for adaptation. We will present the goal-oriented error estimation procedure, where such criteria are derived from an objective functional that represents the observables to be computed most accurately. Even though this approach is well studied, it is rarely used in the geophysics community. A related strategy to make finer resolution manageable is to design methods that automate the inference of model parameters. Tweaking more than a handful of numbers and judging the quality of the simulation by adhoc comparisons to known facts and observations is a tedious task and fundamentally limited by the turnaround times

  2. Structural considerations for a software life cycle dynamic simulation model

    NASA Technical Reports Server (NTRS)

    Tausworthe, R. C.; Mckenzie, M.; Lin, C. Y.

    1983-01-01

    This paper presents the results of a preliminary study into the prospects for simulating the software implementation and maintenance life cycle process, with the aim of producing a computerized tool for use by management and software engineering personnel in project planning, tradeoff studies involving product, environmental, situational, and technological factors, and training. The approach taken is the modular application of a 'flow of resource' concept to the systems dynamics simulation modeling technique. The software life cycle process is represented as a number of stochastic, time-varying, interacting work tasks that each achieves one of the project milestones. Each task is characterized by the item produced, the personnel applied, and the budgetary profile.

  3. Career Adaptability Development in Adolescence: Multiple Predictors and Effect on Sense of Power and Life Satisfaction

    ERIC Educational Resources Information Center

    Hirschi, Andreas

    2009-01-01

    This longitudinal panel study investigated predictors of career adaptability development and its effect on development of sense of power and experience of life satisfaction among 330 Swiss eighth graders. A multivariate measure of career adaptability consisting of career choice readiness, planning, exploration, and confidence was applied. Based on…

  4. Family Socioeconomic Status and Student Adaptation to School Life: Looking beyond Grades

    ERIC Educational Resources Information Center

    Carvalho, Renato G.; Novo, Rosa F.

    2012-01-01

    Introduction: In this quantitative, cross-sectional study we analyse the relationship between family socioeconomic status (SES) and students' adaptation to school life, as expressed through several indicators of achievement, integration (adaptation to transitions, behaviour problems, risk behaviours, interpersonal difficulties, participation in…

  5. Adaptation.

    PubMed

    Broom, Donald M

    2006-01-01

    The term adaptation is used in biology in three different ways. It may refer to changes which occur at the cell and organ level, or at the individual level, or at the level of gene action and evolutionary processes. Adaptation by cells, especially nerve cells helps in: communication within the body, the distinguishing of stimuli, the avoidance of overload and the conservation of energy. The time course and complexity of these mechanisms varies. Adaptive characters of organisms, including adaptive behaviours, increase fitness so this adaptation is evolutionary. The major part of this paper concerns adaptation by individuals and its relationships to welfare. In complex animals, feed forward control is widely used. Individuals predict problems and adapt by acting before the environmental effect is substantial. Much of adaptation involves brain control and animals have a set of needs, located in the brain and acting largely via motivational mechanisms, to regulate life. Needs may be for resources but are also for actions and stimuli which are part of the mechanism which has evolved to obtain the resources. Hence pigs do not just need food but need to be able to carry out actions like rooting in earth or manipulating materials which are part of foraging behaviour. The welfare of an individual is its state as regards its attempts to cope with its environment. This state includes various adaptive mechanisms including feelings and those which cope with disease. The part of welfare which is concerned with coping with pathology is health. Disease, which implies some significant effect of pathology, always results in poor welfare. Welfare varies over a range from very good, when adaptation is effective and there are feelings of pleasure or contentment, to very poor. A key point concerning the concept of individual adaptation in relation to welfare is that welfare may be good or poor while adaptation is occurring. Some adaptation is very easy and energetically cheap and

  6. Hydrodynamics in adaptive resolution particle simulations: Multiparticle collision dynamics

    SciTech Connect

    Alekseeva, Uliana; Winkler, Roland G.; Sutmann, Godehard

    2016-06-01

    A new adaptive resolution technique for particle-based multi-level simulations of fluids is presented. In the approach, the representation of fluid and solvent particles is changed on the fly between an atomistic and a coarse-grained description. The present approach is based on a hybrid coupling of the multiparticle collision dynamics (MPC) method and molecular dynamics (MD), thereby coupling stochastic and deterministic particle-based methods. Hydrodynamics is examined by calculating velocity and current correlation functions for various mixed and coupled systems. We demonstrate that hydrodynamic properties of the mixed fluid are conserved by a suitable coupling of the two particle methods, and that the simulation results agree well with theoretical expectations.

  7. Finite element simulation of adaptive aerospace structures with SMA actuators

    NASA Astrophysics Data System (ADS)

    Frautschi, Jason; Seelecke, Stefan

    2003-07-01

    The particular demands of aerospace engineering have spawned many of the developments in the field of adaptive structures. Shape memory alloys are particularly attractive as actuators in these types of structures due to their large strains, high specific work output and potential for structural integration. However, the requisite extensive physical testing has slowed development of potential applications and highlighted the need for a simulation tool for feasibility studies. In this paper we present an implementation of an extended version of the M'ller-Achenbach SMA model into a commercial finite element code suitable for such studies. Interaction between the SMA model and the solution algorithm for the global FE equations is thoroughly investigated with respect to the effect of tolerances and time step size on convergence, computational cost and accuracy. Finally, a simulation of a SMA-actuated flexible trailing edge of an aircraft wing modeled with beam elements is presented.

  8. Developing adaptive QM/MM computer simulations for electrochemistry.

    PubMed

    Dohm, Sebastian; Spohr, Eckhard; Korth, Martin

    2017-01-05

    We report the development of adaptive QM/MM computer simulations for electrochemistry, providing public access to all sources via the free and open source software development model. We present a modular workflow-based MD simulation code as a platform for algorithms for partitioning space into different regions, which can be treated at different levels of theory on a per-timestep basis. Currently implemented algorithms focus on targeting molecules and their solvation layers relevant to electrochemistry. Instead of using built-in forcefields and quantum mechanical methods, the code features a universal interface, which allows for extension to a range of external forcefield programs and programs for quantum mechanical calculations, thus enabling the user to readily implement interfaces to those programs. The purpose of this article is to describe our codes and illustrate its usage. © 2016 Wiley Periodicals, Inc.

  9. Composition and adaptation in the life of Robert Schumann.

    PubMed

    Graves, John S

    2005-01-01

    The composer Robert Schumann, who suffered from bipolar disorder, utilized his impressive musical and literary talents in attempts to adapt to multiple developmental traumas, separations, and losses as well as to the ongoing ravages of his mood disorder. By analyzing several of his Lieder, the author formulates and describes several defense mechanisms involved in these adaptations. These include identification with the lost object, the use of transitional objects and phenomena, sublimation, denial, minimization, idealization, playfulness, and the employment of healthy obsessive traits. Schumann utilized these adaptive defenses successfully for a brief period, thus coping with a difficult separation from his fiancée, Clara. Ultimately, however, he was unable to experience mature mourning regarding the deaths of several family members. The author, drawing on his extensive experience with treating bipolar individuals in outpatient settings, discusses some of the difficulties that many bipolar patients like Schumann have with mourning, including early developmental vulnerabilities to separation and loss, the disorganizing effects of bipolar mood episodes on cognition and self-coherence, the need to camouflage affects reminiscent of bipolar mood episodes, and experiencing these affects and mood episodes as traumatic reoccurrences. By studying the biographies of creative individuals such as Schumann, clinicians can expand their appreciation of their patients' adaptive capacities and thus assist them in restoring a sense of hope and vitality in their lives.

  10. Adaptive and predictive control of a simulated robot arm.

    PubMed

    Tolu, Silvia; Vanegas, Mauricio; Garrido, Jesús A; Luque, Niceto R; Ros, Eduardo

    2013-06-01

    In this work, a basic cerebellar neural layer and a machine learning engine are embedded in a recurrent loop which avoids dealing with the motor error or distal error problem. The presented approach learns the motor control based on available sensor error estimates (position, velocity, and acceleration) without explicitly knowing the motor errors. The paper focuses on how to decompose the input into different components in order to facilitate the learning process using an automatic incremental learning model (locally weighted projection regression (LWPR) algorithm). LWPR incrementally learns the forward model of the robot arm and provides the cerebellar module with optimal pre-processed signals. We present a recurrent adaptive control architecture in which an adaptive feedback (AF) controller guarantees a precise, compliant, and stable control during the manipulation of objects. Therefore, this approach efficiently integrates a bio-inspired module (cerebellar circuitry) with a machine learning component (LWPR). The cerebellar-LWPR synergy makes the robot adaptable to changing conditions. We evaluate how this scheme scales for robot-arms of a high number of degrees of freedom (DOFs) using a simulated model of a robot arm of the new generation of light weight robots (LWRs).

  11. Efficient Combustion Simulation via the Adaptive Wavelet Collocation Method

    NASA Astrophysics Data System (ADS)

    Lung, Kevin; Brown-Dymkoski, Eric; Guerrero, Victor; Doran, Eric; Museth, Ken; Balme, Jo; Urberger, Bob; Kessler, Andre; Jones, Stephen; Moses, Billy; Crognale, Anthony

    Rocket engine development continues to be driven by the intuition and experience of designers, progressing through extensive trial-and-error test campaigns. Extreme temperatures and pressures frustrate direct observation, while high-fidelity simulation can be impractically expensive owing to the inherent muti-scale, multi-physics nature of the problem. To address this cost, an adaptive multi-resolution PDE solver has been designed which targets the high performance, many-core architecture of GPUs. The adaptive wavelet collocation method is used to maintain a sparse-data representation of the high resolution simulation, greatly reducing the memory footprint while tightly controlling physical fidelity. The tensorial, stencil topology of wavelet-based grids lends itself to highly vectorized algorithms which are necessary to exploit the performance of GPUs. This approach permits efficient implementation of direct finite-rate kinetics, and improved resolution of steep thermodynamic gradients and the smaller mixing scales that drive combustion dynamics. Resolving these scales is crucial for accurate chemical kinetics, which are typically degraded or lost in statistical modeling approaches.

  12. Animal Adaptations. Animal Life in Action[TM]. Schlessinger Science Library. [Videotape].

    ERIC Educational Resources Information Center

    2000

    This 23-minute videotape for grades 5-8, presents the myriad of animal life that exists on the planet. Students can view and perform experiments and investigations that help explain animal traits and habits. As animals adapt to new environments, their bodies and life cycles may change over thousands of years. In this video, students find out about…

  13. Career Adaptability, Hope, Optimism, and Life Satisfaction in Italian and Swiss Adolescents

    ERIC Educational Resources Information Center

    Santilli, Sara; Marcionetti, Jenny; Rochat, Shékina; Rossier, Jérôme; Nota, Laura

    2017-01-01

    The consequences of economic crisis are different from one European context to the other. Based on life design (LD) approach, the present study focused on two variables--career adaptability and a positive orientation toward future (hope and optimism)--relevant to coping with the current work context and their role in affecting life satisfaction. A…

  14. Numerical simulation of immiscible viscous fingering using adaptive unstructured meshes

    NASA Astrophysics Data System (ADS)

    Adam, A.; Salinas, P.; Percival, J. R.; Pavlidis, D.; Pain, C.; Muggeridge, A. H.; Jackson, M.

    2015-12-01

    Displacement of one fluid by another in porous media occurs in various settings including hydrocarbon recovery, CO2 storage and water purification. When the invading fluid is of lower viscosity than the resident fluid, the displacement front is subject to a Saffman-Taylor instability and is unstable to transverse perturbations. These instabilities can grow, leading to fingering of the invading fluid. Numerical simulation of viscous fingering is challenging. The physics is controlled by a complex interplay of viscous and diffusive forces and it is necessary to ensure physical diffusion dominates numerical diffusion to obtain converged solutions. This typically requires the use of high mesh resolution and high order numerical methods. This is computationally expensive. We demonstrate here the use of a novel control volume - finite element (CVFE) method along with dynamic unstructured mesh adaptivity to simulate viscous fingering with higher accuracy and lower computational cost than conventional methods. Our CVFE method employs a discontinuous representation for both pressure and velocity, allowing the use of smaller control volumes (CVs). This yields higher resolution of the saturation field which is represented CV-wise. Moreover, dynamic mesh adaptivity allows high mesh resolution to be employed where it is required to resolve the fingers and lower resolution elsewhere. We use our results to re-examine the existing criteria that have been proposed to govern the onset of instability.Mesh adaptivity requires the mapping of data from one mesh to another. Conventional methods such as consistent interpolation do not readily generalise to discontinuous fields and are non-conservative. We further contribute a general framework for interpolation of CV fields by Galerkin projection. The method is conservative, higher order and yields improved results, particularly with higher order or discontinuous elements where existing approaches are often excessively diffusive.

  15. The yak genome and adaptation to life at high altitude.

    PubMed

    Qiu, Qiang; Zhang, Guojie; Ma, Tao; Qian, Wubin; Wang, Junyi; Ye, Zhiqiang; Cao, Changchang; Hu, Quanjun; Kim, Jaebum; Larkin, Denis M; Auvil, Loretta; Capitanu, Boris; Ma, Jian; Lewin, Harris A; Qian, Xiaoju; Lang, Yongshan; Zhou, Ran; Wang, Lizhong; Wang, Kun; Xia, Jinquan; Liao, Shengguang; Pan, Shengkai; Lu, Xu; Hou, Haolong; Wang, Yan; Zang, Xuetao; Yin, Ye; Ma, Hui; Zhang, Jian; Wang, Zhaofeng; Zhang, Yingmei; Zhang, Dawei; Yonezawa, Takahiro; Hasegawa, Masami; Zhong, Yang; Liu, Wenbin; Zhang, Yan; Huang, Zhiyong; Zhang, Shengxiang; Long, Ruijun; Yang, Huanming; Wang, Jian; Lenstra, Johannes A; Cooper, David N; Wu, Yi; Wang, Jun; Shi, Peng; Wang, Jian; Liu, Jianquan

    2012-07-01

    Domestic yaks (Bos grunniens) provide meat and other necessities for Tibetans living at high altitude on the Qinghai-Tibetan Plateau and in adjacent regions. Comparison between yak and the closely related low-altitude cattle (Bos taurus) is informative in studying animal adaptation to high altitude. Here, we present the draft genome sequence of a female domestic yak generated using Illumina-based technology at 65-fold coverage. Genomic comparisons between yak and cattle identify an expansion in yak of gene families related to sensory perception and energy metabolism, as well as an enrichment of protein domains involved in sensing the extracellular environment and hypoxic stress. Positively selected and rapidly evolving genes in the yak lineage are also found to be significantly enriched in functional categories and pathways related to hypoxia and nutrition metabolism. These findings may have important implications for understanding adaptation to high altitude in other animal species and for hypoxia-related diseases in humans.

  16. Evolution and adaptation of fungi at boundaries of life

    NASA Astrophysics Data System (ADS)

    Onofri, S.; Selbmann, L.; de Hoog, G. S.; Grube, M.; Barreca, D.; Ruisi, S.; Zucconi, L.

    The Antarctic cryptoendolithic fungi of the ice-free desert could have evolved genetically and geographically isolated since the separation of the Continent from the Gondwanaland. The resulting harsh environmental conditions due to the migration of Antarctica to the South Pole led to a strong selective pressure possibly promoting adaptive radiation and speciation. Microorganisms evolved during this unique process are adapted to colonize what is known as the closest Martian environment on Earth. For this reason they have been already suggested as the best eukaryotic model for exobiological speculations. The results on freeze and thawing, UV exposure and osmotic stress tolerance here reported highlight an uncommon ability of surviving under these external pressures. Studies on their ability to withstand space conditions are in progress in view of the opportunity of direct space exposure on the International Space Station. The results could give new tools to solve the conflict concerning the Panspermia hypothesis.

  17. Monte Carlo simulation by computer for life-cycle costing

    NASA Technical Reports Server (NTRS)

    Gralow, F. H.; Larson, W. J.

    1969-01-01

    Prediction of behavior and support requirements during the entire life cycle of a system enables accurate cost estimates by using the Monte Carlo simulation by computer. The system reduces the ultimate cost to the procuring agency because it takes into consideration the costs of initial procurement, operation, and maintenance.

  18. Thermal Modeling and Feedback Requirements for LIFE Neutronic Simulations

    SciTech Connect

    Seifried, J E

    2009-07-15

    An initial study is performed to determine how temperature considerations affect LIFE neutronic simulations. Among other figures of merit, the isotopic mass accumulation, thermal power, tritium breeding, and criticality are analyzed. Possible fidelities of thermal modeling and degrees of coupling are explored. Lessons learned from switching and modifying nuclear datasets is communicated.

  19. Health Condition and Quality of Life in Older Adults: Adaptation of QOLIE-89

    ERIC Educational Resources Information Center

    Efklides, Anastasia; Varsami, Maria; Mitadi, Ioanna; Economidis, Dimitrios

    2006-01-01

    This study aimed at adapting the Questionnaire Quality of Life in Epilepsy (QOLIE-89 version 1.0: Vickrey et al., 1993), Quality of Life in Epilepsy QoLIE-89 RAND (Santa Monica, CA)] so that it may be used to measure quality of life (QoL) of older adults, healthy or suffering from various chronic illnesses. The participants were 202 older adults…

  20. Simulation of nonpoint source contamination based on adaptive mesh refinement

    NASA Astrophysics Data System (ADS)

    Kourakos, G.; Harter, T.

    2014-12-01

    Contamination of groundwater aquifers from nonpoint sources is a worldwide problem. Typical agricultural groundwater basins receive contamination from a large array (in the order of ~10^5-6) of spatially and temporally heterogeneous sources such as fields, crops, dairies etc, while the received contaminants emerge at significantly uncertain time lags to a large array of discharge surfaces such as public supply, domestic and irrigation wells and streams. To support decision making in such complex regimes several approaches have been developed, which can be grouped into 3 categories: i) Index methods, ii)regression methods and iii) physically based methods. Among the three, physically based methods are considered more accurate, but at the cost of computational demand. In this work we present a physically based simulation framework which exploits the latest hardware and software developments to simulate large (>>1,000 km2) groundwater basins. First we simulate groundwater flow using a sufficiently detailed mesh to capture the spatial heterogeneity. To achieve optimal mesh quality we combine adaptive mesh refinement with the nonlinear solution for unconfined flow. Starting from a coarse grid the mesh is refined iteratively in the parts of the domain where the flow heterogeneity appears higher resulting in optimal grid. Secondly we simulate the nonpoint source pollution based on the detailed velocity field computed from the previous step. In our approach we use the streamline model where the 3D transport problem is decomposed into multiple 1D transport problems. The proposed framework is applied to simulate nonpoint source pollution in the Central Valley aquifer system, California.

  1. Using Adaptive Mesh Refinment to Simulate Storm Surge

    NASA Astrophysics Data System (ADS)

    Mandli, K. T.; Dawson, C.

    2012-12-01

    Coastal hazards related to strong storms such as hurricanes and typhoons are one of the most frequently recurring and wide spread hazards to coastal communities. Storm surges are among the most devastating effects of these storms, and their prediction and mitigation through numerical simulations is of great interest to coastal communities that need to plan for the subsequent rise in sea level during these storms. Unfortunately these simulations require a large amount of resolution in regions of interest to capture relevant effects resulting in a computational cost that may be intractable. This problem is exacerbated in situations where a large number of similar runs is needed such as in design of infrastructure or forecasting with ensembles of probable storms. One solution to address the problem of computational cost is to employ adaptive mesh refinement (AMR) algorithms. AMR functions by decomposing the computational domain into regions which may vary in resolution as time proceeds. Decomposing the domain as the flow evolves makes this class of methods effective at ensuring that computational effort is spent only where it is needed. AMR also allows for placement of computational resolution independent of user interaction and expectation of the dynamics of the flow as well as particular regions of interest such as harbors. The simulation of many different applications have only been made possible by using AMR-type algorithms, which have allowed otherwise impractical simulations to be performed for much less computational expense. Our work involves studying how storm surge simulations can be improved with AMR algorithms. We have implemented relevant storm surge physics in the GeoClaw package and tested how Hurricane Ike's surge into Galveston Bay and up the Houston Ship Channel compares to available tide gauge data. We will also discuss issues dealing with refinement criteria, optimal resolution and refinement ratios, and inundation.

  2. Adapting a weather forecast model for greenhouse gas simulation

    NASA Astrophysics Data System (ADS)

    Polavarapu, S. M.; Neish, M.; Tanguay, M.; Girard, C.; de Grandpré, J.; Gravel, S.; Semeniuk, K.; Chan, D.

    2015-12-01

    The ability to simulate greenhouse gases on the global domain is useful for providing boundary conditions for regional flux inversions, as well as for providing reference data for bias correction of satellite measurements. Given the existence of operational weather and environmental prediction models and assimilation systems at Environment Canada, it makes sense to use these tools for greenhouse gas simulations. In this work, we describe the adaptations needed to reasonably simulate CO2 with a weather forecast model. The main challenges were the implementation of a mass conserving advection scheme, and the careful implementation of a mixing ratio defined with respect to dry air. The transport of tracers through convection was also added, and the vertical mixing through the boundary layer was slightly modified. With all these changes, the model conserves CO2 mass well on the annual time scale, and the high resolution (0.9 degree grid spacing) permits a good description of synoptic scale transport. The use of a coupled meteorological/tracer transport model also permits an assessment of approximations needed in offline transport model approaches, such as the neglect of water vapour mass when computing a tracer mixing ratio with respect to dry air.

  3. Measurements of contrast sensitivity by an adaptive optics visual simulator

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Tatsuo; Ucikawa, Keiji

    2015-08-01

    We developed an adaptive optics visual simulator (AOVS) to study the relationship between the contrast sensitivity and higher-order wavefront aberrations of human eyes. A desired synthetic aberration was virtually generated on a subject eye by the AOVS, and red laser light was used to measure the aberrations. The contrast sensitivity was measured in a psychophysical experiment using visual stimulus patterns provided by a large-contrast-range imaging system, which included two liquid crystal displays illuminated by red light emitting diodes from the backside. The diameter of the pupil was set to 4 mm by an artificial aperture, and the retinal illuminance of the stimulus image was controlled to 10 Td. Experiments conducted with four normal subjects revealed that their contrast sensitivity to a high-spatial-frequency vertical sinusoidal grating pattern was lower in the presence of a horizontal coma aberration than in the presence of a vertical coma or no aberrations ( p < 0.02, Nagai method).

  4. Scale Adaptive Simulation Model for the Darrieus Wind Turbine

    NASA Astrophysics Data System (ADS)

    Rogowski, K.; Hansen, M. O. L.; Maroński, R.; Lichota, P.

    2016-09-01

    Accurate prediction of aerodynamic loads for the Darrieus wind turbine using more or less complex aerodynamic models is still a challenge. One of the problems is the small amount of experimental data available to validate the numerical codes. The major objective of the present study is to examine the scale adaptive simulation (SAS) approach for performance analysis of a one-bladed Darrieus wind turbine working at a tip speed ratio of 5 and at a blade Reynolds number of 40 000. The three-dimensional incompressible unsteady Navier-Stokes equations are used. Numerical results of aerodynamic loads and wake velocity profiles behind the rotor are compared with experimental data taken from literature. The level of agreement between CFD and experimental results is reasonable.

  5. Knowledge Based Simulation: An Artificial Intelligence Approach to System Modeling and Automating the Simulation Life Cycle.

    DTIC Science & Technology

    1988-04-13

    Simulation: An Artificial Intelligence Approach to System Modeling and Automating the Simulation Life Cycle Mark S. Fox, Nizwer Husain, Malcolm...years of research in the application of Artificial Intelligence to Simulation. Our focus has been in two areas: the use of Al knowledge representation...this problem by using Artificial Intelligence (Al) knowledge representation techniques, such as frames, to represent the objects and their

  6. Adaptive responses of energy storage and fish life histories to climatic gradients.

    PubMed

    Giacomini, Henrique C; Shuter, Brian J

    2013-12-21

    Energy storage is a common adaptation of fish living in seasonal environments. For some species, the energy accumulated during the growing season, and stored primarily as lipids, is crucial to preventing starvation mortality over winter. Thus, in order to understand the adaptive responses of fish life history to climate, it is important to determine how energy should be allocated to storage and how it trades off with the other body components that contribute to fitness. In this paper, we extend previous life history theory to include an explicit representation of how the seasonal allocation of energy to storage acts as a constraint on fish growth. We show that a strategy that privileges allocation to structural mass in the first part of the growing season and switches to storage allocation later on, as observed empirically in several fish species, is the strategy that maximizes growth efficiency and hence is expected to be favored by natural selection. Stochastic simulations within this theoretical framework demonstrate that the relative performance of this switching strategy is robust to a wide range of fluctuations in growing season length, and to moderate short-term (i.e., daily) fluctuations in energy intake and/or expenditure within the growing season. We then integrate this switching strategy with a biphasic growth modeling framework to predict typical growth rates of walleye Sander vitreus, a cool water species, and lake trout Salvelinus namaycush, a cold water specialist, across a climatic gradient in North America. As predicted, growth rates increased linearly with the duration of the growing season. Regression line intercepts were negative, indicating that growth can only occur when growing season length exceeds a threshold necessary to produce storage for winter survival. The model also reveals important differences between species, showing that observed growth rates of lake trout are systematically higher than those of walleye in relatively colder lakes

  7. Family Adaptation to the Demands of Army Life: A Review of Findings

    DTIC Science & Technology

    1994-01-01

    which the spouses work as a team but in which each spouse can function well independently probably adapt most easily to Army life . The Army can...marital and family life as well as to Army life " (Bowen, 1990a, p. 15). * An outcome or level of "fit" between families and systems in their environment...personal or family needs due to military hardships or conditions. While Bowen (1990b) 2 SATISFACTION WITH ARMY LIFE High Low F ltigh GROUP I GROUP 2

  8. Engineering and simulation of life science Spacelab experiments

    NASA Technical Reports Server (NTRS)

    Bush, B.; Rummel, J.; Johnston, R. S.

    1977-01-01

    Approaches to the planning and realization of Spacelab life sciences experiments, which may involve as many as 16 Space Shuttle missions and 100 tests, are discussed. In particular, a Spacelab simulation program, designed to evaluate problems associated with the use of live animal specimens, the constraints imposed by zero gravity on equipment operation, training of investigators and data management, is described. The simulated facility approximates the hardware and support systems of a current European Space Agency Spacelab model. Preparations necessary for the experimental program, such as crew activity plans, payload documentation and inflight experimental procedures are developed; health problems of the crew, including human/animal microbial contamination, are also assessed.

  9. Life history and evolutionary adaptation of Pacific salmon and its application in management

    SciTech Connect

    Wevers, M.J.

    1993-01-01

    An approach to understanding and managing anadromous salmon, steelhead, and sea-run cutthroat trout (Oncorhynchus spp.) based on life history and evolutionary adaptive capacities of species and stocks is presented. Species, stocks, and local populations are viewed as systems that are continuously adapting to changing environmental conditions. They have the potential capacity to evolve in different ways in different environments through both life history and evolutionary adaptation. Habitat organization forms a template for genus, species, stock, and local population life history organization. Harvesting, habitat alteration resulting from land use practices and other human activities can alter the organization and adaptive capacities of species and stocks, and thus their long term persistence. The adaptive capacity of Oncorhynchus relative to its habitat and management environment is examined at the species, stock, and local population levels. Life history characteristics of representative stocks and local populations are analyzed using Detrended Correspondence Analysis (DECORANA). Fresh water migration distance and latitude are used to [open quotes]explain[close quotes] ordination patterns of Oncorhynchus species in the North Pacific Basin. Fresh water migration difficulty and mean annual runoff as used to interpret life history patterns of Columbia Basin chinook salmon stocks. Upstream migration difficulty and fall water temperatures are used to explain the ordination patterns of local populations of Willamette spring chinook salmon. Fishery management practices are examined in terms of their impacts on the organization and adaptive capacity of species, stocks, and local populations of Oncorhynchus. Management generalizations and guidelines derived from the life history theory are applied to management of Willamette spring chinook salmon.

  10. LDRD Final Report: Adaptive Methods for Laser Plasma Simulation

    SciTech Connect

    Dorr, M R; Garaizar, F X; Hittinger, J A

    2003-01-29

    The goal of this project was to investigate the utility of parallel adaptive mesh refinement (AMR) in the simulation of laser plasma interaction (LPI). The scope of work included the development of new numerical methods and parallel implementation strategies. The primary deliverables were (1) parallel adaptive algorithms to solve a system of equations combining plasma fluid and light propagation models, (2) a research code implementing these algorithms, and (3) an analysis of the performance of parallel AMR on LPI problems. The project accomplished these objectives. New algorithms were developed for the solution of a system of equations describing LPI. These algorithms were implemented in a new research code named ALPS (Adaptive Laser Plasma Simulator) that was used to test the effectiveness of the AMR algorithms on the Laboratory's large-scale computer platforms. The details of the algorithm and the results of the numerical tests were documented in an article published in the Journal of Computational Physics [2]. A principal conclusion of this investigation is that AMR is most effective for LPI systems that are ''hydrodynamically large'', i.e., problems requiring the simulation of a large plasma volume relative to the volume occupied by the laser light. Since the plasma-only regions require less resolution than the laser light, AMR enables the use of efficient meshes for such problems. In contrast, AMR is less effective for, say, a single highly filamented beam propagating through a phase plate, since the resulting speckle pattern may be too dense to adequately separate scales with a locally refined mesh. Ultimately, the gain to be expected from the use of AMR is highly problem-dependent. One class of problems investigated in this project involved a pair of laser beams crossing in a plasma flow. Under certain conditions, energy can be transferred from one beam to the other via a resonant interaction with an ion acoustic wave in the crossing region. AMR provides an

  11. "Replaying Life's Tape": Simulations, metaphors, and historicity in Stephen Jay Gould's view of life.

    PubMed

    Sepkoski, David

    2016-08-01

    In a famous thought experiment, Stephen Jay Gould asked whether, if one could somehow rewind the history of life back to its initial starting point, the same results would obtain when the "tape" was run forward again. This hypothetical experiment is generally understood as a metaphor supporting Gould's philosophy of evolutionary contingency, which he developed and promoted from the late 1980s until his death in 2002. However, there was a very literal, non-metaphorical inspiration for Gould's thought experiment: since the early 1970s, Gould, along with a group of other paleontologists, was actively engaged in attempts to model and reconstruct the history of life using computer simulations and database analysis. These simulation projects not only demonstrate the impact that computers had on data analysis in paleontology, but also shed light on the close relationship between models and empirical data in data-oriented science. In a sense, I will argue, the models developed by paleontologists through simulation and quantitative analysis of the empirical fossil record in the 1970s and beyond were literal attempts to "replay life's tape" by reconstructing the history of life as data.

  12. Software life cycle dynamic simulation model: The organizational performance submodel

    NASA Technical Reports Server (NTRS)

    Tausworthe, Robert C.

    1985-01-01

    The submodel structure of a software life cycle dynamic simulation model is described. The software process is divided into seven phases, each with product, staff, and funding flows. The model is subdivided into an organizational response submodel, a management submodel, a management influence interface, and a model analyst interface. The concentration here is on the organizational response model, which simulates the performance characteristics of a software development subject to external and internal influences. These influences emanate from two sources: the model analyst interface, which configures the model to simulate the response of an implementing organization subject to its own internal influences, and the management submodel that exerts external dynamic control over the production process. A complete characterization is given of the organizational response submodel in the form of parameterized differential equations governing product, staffing, and funding levels. The parameter values and functions are allocated to the two interfaces.

  13. Cognitive adaptation theory and quality of life in late-stage cancer patients.

    PubMed

    Christianson, Heidi Fowell; Weis, Jo M; Fouad, Nadya A

    2013-01-01

    In this study, the question of whether using slightly illusionary, positive attributions of self, control, and meaning (e.g., cognitive adaptation theory), in the face of disconfirmatory evidence, facilitates quality of life in late-stage cancer patients was examined. Eighty late-stage cancer patients (Mean age = 59.7, SD = 12.5; 48.8% male, 51.2% female; varying cancer diagnoses) who recently failed or refused first line anti-neoplastic treatment completed questionnaires assessing meaning, control, self-esteem, and optimism, as well as physical and psychological quality of life. Findings suggest that greater self-esteem, control, and meaning predicted physical and psychological quality of life, with physical quality of life being influenced by control beliefs and psychological quality of life influenced by self-esteem. Optimism independently predicted physical quality of life and neither mediated nor moderated the relationship between cognitive adaptation and quality of life. Findings suggest that slightly positive, illusionary beliefs of self, control, and meaning predicted quality of life even in the presence of clear, disconfirmatory environmental evidence.

  14. Evaluation of individual quality of life among hemodialysis patients: nominated themes using SEIQoL-adapted

    PubMed Central

    Matlabi, Hossein; Ahmadzadeh, Sharareh

    2017-01-01

    Background Quality of life (QoL) has become an important issue for patients with chronic renal failure diseases who are permanently undergoing hemodialysis. In this study, an adapted schedule for the evaluation of individual quality of life (SEIQoL-adapted) was used to evaluate QoL among hemodialysis patients, to explore their views about the most important aspects of life satisfaction. Methods and results A multiple approach design and convenience sampling were applied to recruit 53 patients from a hemodialysis unit in Iran. Data were collected through structured interviews and then analyzed using conventional content analysis. A total score for QoL was calculated using scale guideline. The most important aspects of life were health, family, financial status, living conditions, leisure activities, relationships and socializing, religious and spiritual issues, medical knowledge, and therapies or treatments. The calculated mean QoL score was 66.2, indicating a relatively high life satisfaction. Males had higher QoL scores than females in both married and single groups. Moreover, the relationships between the QoL scores and education, job and marital status were not statistically significant. Conclusion The SEIQoL-adapted revealed reasonable lay definitions of QoL in a group of patients following chronic renal failure. The patients’ views of the aspects of life could be used by health policy makers, clinicians, and caregivers as a reliable guide to the most important priorities for treatment and medical interventions. PMID:28031703

  15. Subjective well-being and adaptation to life events: a meta-analysis.

    PubMed

    Luhmann, Maike; Hofmann, Wilhelm; Eid, Michael; Lucas, Richard E

    2012-03-01

    Previous research has shown that major life events can have short- and long-term effects on subjective well-being (SWB). The present meta-analysis examines (a) whether life events have different effects on affective and cognitive well-being and (b) how the rate of adaptation varies across different life events. Longitudinal data from 188 publications (313 samples, N = 65,911) were integrated to describe the reaction and adaptation to 4 family events (marriage, divorce, bereavement, childbirth) and 4 work events (unemployment, reemployment, retirement, relocation/migration). The findings show that life events have very different effects on affective and cognitive well-being and that for most events the effects of life events on cognitive well-being are stronger and more consistent across samples. Different life events differ in their effects on SWB, but these effects are not a function of the alleged desirability of events. The results are discussed with respect to their theoretical implications, and recommendations for future studies on adaptation are given.

  16. Acculturation and adaptation of Soviet Jewish refugee adolescents: predictors of adjustment across life domains.

    PubMed

    Birman, Dina; Trickett, Edison J; Vinokurov, Andrey

    2002-10-01

    This study explores how acculturation is related to adaptation across different life spheres for 162 Soviet Jewish refugee adolescents in a suburban community in Maryland. Because the different contexts of refugee adolescents' lives vary in acculturative demands, different patterns of acculturation should be related to adaptation in different life spheres. The study uses a multidimensional measure of acculturation and assesses acculturation to both American and Russian cultures as it relates to psychological adaptation, peer relations, and school and family outcomes. Findings support the general ecological thesis that acculturation to different cultures is differentially related to adaptation across life domains. Acculturation to American culture predicted better grades and perceived support from American peers. Acculturation to Russian culture predicted perceived support from Russian peers. Both American acculturation and Russian acculturation predicted reduced loneliness and perceived support from parents. Further, different dimensions of acculturation, such as language and identity, were differentially related to adaptation. Implications for acculturation theory and measurement are drawn, and cautions are offered about the interpretation of acculturation studies using single proxies such as language use or preference.

  17. Adapting and Evaluating a Tree of Life Group for Women with Learning Disabilities

    ERIC Educational Resources Information Center

    Randle-Phillips, Cathy; Farquhar, Sarah; Thomas, Sally

    2016-01-01

    Background: This study describes how a specific narrative therapy approach called 'the tree of life' was adapted to run a group for women with learning disabilities. The group consisted of four participants and ran for five consecutive weeks. Materials and Methods: Participants each constructed a tree to represent their lives and presented their…

  18. Psychometric Characteristics of the Korean Version of the Satisfaction with Life Scale Adapted for Children

    ERIC Educational Resources Information Center

    Lim, Young-Jin

    2015-01-01

    The aim of this study was to examine the internal consistency reliability, test-retest reliability, factorial structure validity, and convergent validity of a Korean version of the Satisfaction With Life Scale adapted for children (K-SWLS-C). Participants consisted of 653 elementary school students (48% were male). The internal consistency of the…

  19. Family Quality of Life: Adaptation to Spanish Population of Several Family Support Questionnaires

    ERIC Educational Resources Information Center

    Balcells-Balcells, A.; Gine, C.; Guardia-Olmos, J.; Summers, J. A.

    2011-01-01

    Background: The concept of family quality of life has emerged as a decisive construct in the last decades to improve the capabilities of families and to assess the outcomes of the services and supports they get. The goal of this research is to adapt three instruments to the Spanish population: the "Beach Center Family Quality of Life…

  20. Adaptive and Maladaptive Perfectionism as Mediators of Adult Attachment Styles and Depression, Hopelessness, and Life Satisfaction

    ERIC Educational Resources Information Center

    Gnilka, Philip B.; Ashby, Jeffrey S.; Noble, Christina M.

    2013-01-01

    This study examined the relationships between adaptive and maladaptive perfectionism, anxious and avoidant adult attachment styles, depression, hopelessness, and life satisfaction among a sample of 180 undergraduate students. Maladaptive perfectionism mediated the relationship between both forms of adult attachment and depression, hopelessness,…

  1. Life-history variation and adaptation in the historically mobile plant Arabidopsis thaliana (Brassicaceae) in North America.

    PubMed

    Griffith, Converse; Kim, Eunsuk; Donohue, Kathleen

    2004-06-01

    We used field-collected seeds of Arabidopsis thaliana (Brassicaceae) to simulate a colonization event of plants from diverse locations into a common environment to compare regionally "local" and "foreign" populations of this historically mobile species. Life history varied among regional groups, but most variation was found among populations within regions. While we found significant differences among populations and regional groups for important life-history characters, we did not find significant differences in performance of plants from different populations or regional groups. Rather, we found evidence that differences in life history contributed to the ability of plants from foreign regions to perform comparably to local Kentucky plants. Had plants from different regions not differed in the timing and size of reproduction, we would have seen that Kentucky (local) plants had higher total fitness via greater reproductive success of individuals that survived to reproduce and that Michigan plants would have had the lowest fitness. The populations are comparably adapted to the environment in Kentucky but through different combinations of life-history characters. Therefore, the life-history variation in this mobile species appears to contribute not to fitness differences among populations but rather to success in colonizing new locations.

  2. Engineering and simulation of life sciences Spacelab experiments

    NASA Technical Reports Server (NTRS)

    Johnston, R. S.; Bush, W. H. Jr; Rummel, J. A.; Alexander, W. C.

    1979-01-01

    The third in a series of Spacelab Mission Development tests was conducted at the Johnson (correction of Johnston) Space Center as a part of the development of Life Sciences experiments for the Space Shuttle era. The latest test was a joint effort of the Ames Research and Johnson Space Centers and utilized animals and men for study. The basic objective of this test was to evaluate the operational concepts planned for the Space Shuttle life science payloads program. A three-man crew (Mission Specialist and two Payload Specialists) conducted 26 experiments and 12 operational tests, which were selected for this 7-day mission simulation. The crew lived on board a simulated Orbiter/Spacelab mockup 24 hr a day. The Orbiter section contained the mid deck crew quarters area, complete with sleeping, galley and waste management provisions. The Spacelab was identical in geometry to the European Space Agency Spacelab design, complete with removable rack sections and stowage provisions. Communications between the crewmen and support personnel were configured and controlled as currently planned for operational shuttle flights. For this test a Science Operations Remote Center was manned at the Ames Research Center and was managed by simulated Mission Control and Payload Operation Control Centers at the Johnson Space Center. This paper presents the test objectives, description of the facilities and test program, and the results of this test.

  3. Engineering and simulation of life sciences Spacelab experiments.

    PubMed

    Johnston, R S; Bush, W H; Rummel, J A; Alexander, W C

    1979-10-01

    The third in a series of Spacelab Mission Development tests was conducted at the Johnson (correction of Johnston) Space Center as a part of the development of Life Sciences experiments for the Space Shuttle era. The latest test was a joint effort of the Ames Research and Johnson Space Centers and utilized animals and men for study. The basic objective of this test was to evaluate the operational concepts planned for the Space Shuttle life science payloads program. A three-man crew (Mission Specialist and two Payload Specialists) conducted 26 experiments and 12 operational tests, which were selected for this 7-day mission simulation. The crew lived on board a simulated Orbiter/Spacelab mockup 24 hr a day. The Orbiter section contained the mid deck crew quarters area, complete with sleeping, galley and waste management provisions. The Spacelab was identical in geometry to the European Space Agency Spacelab design, complete with removable rack sections and stowage provisions. Communications between the crewmen and support personnel were configured and controlled as currently planned for operational shuttle flights. For this test a Science Operations Remote Center was manned at the Ames Research Center and was managed by simulated Mission Control and Payload Operation Control Centers at the Johnson Space Center. This paper presents the test objectives, description of the facilities and test program, and the results of this test.

  4. Theory, modelling and simulation in origins of life studies.

    PubMed

    Coveney, Peter V; Swadling, Jacob B; Wattis, Jonathan A D; Greenwell, H Christopher

    2012-08-21

    Origins of life studies represent an exciting and highly multidisciplinary research field. In this review we focus on the contributions made by theory, modelling and simulation to addressing fundamental issues in the domain and the advances these approaches have helped to make in the field. Theoretical approaches will continue to make a major impact at the "systems chemistry" level based on the analysis of the remarkable properties of nonlinear catalytic chemical reaction networks, which arise due to the auto-catalytic and cross-catalytic nature of so many of the putative processes associated with self-replication and self-reproduction. In this way, we describe inter alia nonlinear kinetic models of RNA replication within a primordial Darwinian soup, the origins of homochirality and homochiral polymerization. We then discuss state-of-the-art computationally-based molecular modelling techniques that are currently being deployed to investigate various scenarios relevant to the origins of life.

  5. Simulating adaptive wood harvest in a changing climate

    NASA Astrophysics Data System (ADS)

    Yousefpour, Rasoul; Nabel, Julia; Pongratz, Julia

    2016-04-01

    The world's forest experience substantial carbon exchange fluxes between land and atmosphere. Large carbon sinks occur in response to changes in environmental conditions (such as climate change and increased atmospheric CO2 concentrations), removing about one quarter of current anthropogenic CO2-emissions. Large sinks also occur due to regrowth of forest on areas of agricultural abandonment or forest management. Forest management, on the other hand, also leads to substantial amounts of carbon being eventually released to the atmosphere. Both sinks and sources attributable to forests are therefore dependent on the intensity of management. Forest management in turn depends on the availability of resources, which is influenced by environmental conditions and sustainability of management systems applied. Estimating future carbon fluxes therefore requires accounting for the interaction of environmental conditions, forest growth, and management. However, this interaction is not fully captured by current modeling approaches: Earth system models depict in detail interactions between climate, the carbon cycle, and vegetation growth, but use prescribed information on management. Resource needs and land management, however, are simulated by Integrated Assessment Models that typically only have coarse representations of the influence of environmental changes on vegetation growth and are typically based on the demand for wood driven by regional population growth and energy needs. Here we present a study that provides the link between environmental conditions, forest growth and management. We extend the land component JSBACH of the Max Planck Institute's Earth system model (MPI-ESM) to simulate potential wood harvest in response to altered growth conditions and thus as adaptive to changing climate and CO2 conditions. We apply the altered model to estimate potential wood harvest for future climates (representative concentration pathways, RCPs) for the management scenario of

  6. Mission simulation as an approach to develop requirements for automation in Advanced Life Support Systems

    NASA Technical Reports Server (NTRS)

    Erickson, J. D.; Eckelkamp, R. E.; Barta, D. J.; Dragg, J.; Henninger, D. L. (Principal Investigator)

    1996-01-01

    This paper examines mission simulation as an approach to develop requirements for automation and robotics for Advanced Life Support Systems (ALSS). The focus is on requirements and applications for command and control, control and monitoring, situation assessment and response, diagnosis and recovery, adaptive planning and scheduling, and other automation applications in addition to mechanized equipment and robotics applications to reduce the excessive human labor requirements to operate and maintain an ALSS. Based on principles of systems engineering, an approach is proposed to assess requirements for automation and robotics using mission simulation tools. First, the story of a simulated mission is defined in terms of processes with attendant types of resources needed, including options for use of automation and robotic systems. Next, systems dynamics models are used in simulation to reveal the implications for selected resource allocation schemes in terms of resources required to complete operational tasks. The simulations not only help establish ALSS design criteria, but also may offer guidance to ALSS research efforts by identifying gaps in knowledge about procedures and/or biophysical processes. Simulations of a planned one-year mission with 4 crewmembers in a Human Rated Test Facility are presented as an approach to evaluation of mission feasibility and definition of automation and robotics requirements.

  7. Mass balances for a biological life support system simulation model

    NASA Technical Reports Server (NTRS)

    Volk, Tyler; Rumel, John D.

    1987-01-01

    Design decisions to aid the development of future space-based biological life support systems (BLSS) can be made with simulation models. Here the biochemical stoichiometry is developed for: (1) protein, carbohydrate, fat, fiber, and lignin production in the edible and inedible parts of plants; (2) food consumption and production of organic solids in urine, feces, and wash water by the humans; and (3) operation of the waste processor. Flux values for all components are derived for a steady-state system with wheat as the sole food source.

  8. Development of the Computer-Adaptive Version of the Late-Life Function and Disability Instrument

    PubMed Central

    Tian, Feng; Kopits, Ilona M.; Moed, Richard; Pardasaney, Poonam K.; Jette, Alan M.

    2012-01-01

    Background. Having psychometrically strong disability measures that minimize response burden is important in assessing of older adults. Methods. Using the original 48 items from the Late-Life Function and Disability Instrument and newly developed items, a 158-item Activity Limitation and a 62-item Participation Restriction item pool were developed. The item pools were administered to a convenience sample of 520 community-dwelling adults 60 years or older. Confirmatory factor analysis and item response theory were employed to identify content structure, calibrate items, and build the computer-adaptive testings (CATs). We evaluated real-data simulations of 10-item CAT subscales. We collected data from 102 older adults to validate the 10-item CATs against the Veteran’s Short Form-36 and assessed test–retest reliability in a subsample of 57 subjects. Results. Confirmatory factor analysis revealed a bifactor structure, and multi-dimensional item response theory was used to calibrate an overall Activity Limitation Scale (141 items) and an overall Participation Restriction Scale (55 items). Fit statistics were acceptable (Activity Limitation: comparative fit index = 0.95, Tucker Lewis Index = 0.95, root mean square error approximation = 0.03; Participation Restriction: comparative fit index = 0.95, Tucker Lewis Index = 0.95, root mean square error approximation = 0.05). Correlation of 10-item CATs with full item banks were substantial (Activity Limitation: r = .90; Participation Restriction: r = .95). Test–retest reliability estimates were high (Activity Limitation: r = .85; Participation Restriction r = .80). Strength and pattern of correlations with Veteran’s Short Form-36 subscales were as hypothesized. Each CAT, on average, took 3.56 minutes to administer. Conclusions. The Late-Life Function and Disability Instrument CATs demonstrated strong reliability, validity, accuracy, and precision. The Late-Life Function and Disability Instrument CAT can achieve

  9. Bringing history to life: simulating landmark experiments in psychology.

    PubMed

    Boynton, David M; Smith, Laurence D

    2006-05-01

    The course in history of psychology can be challenging for students, many of whom enter it with little background in history and faced with unfamiliar names and concepts. The sheer volume of material can encourage passive memorization unless efforts are made to increase student involvement. As part of a trend toward experiential history, historians of science have begun to supplement their lectures with demonstrations of classic physics experiments as a way to bring the history of science to life. Here, the authors report on computer simulations of five landmark experiments from early experimental psychology in the areas of reaction time, span of attention, and apparent motion. The simulations are designed not only to permit hands-on replication of historically important results but also to reproduce the experimental procedures closely enough that students can gain a feel for the nature of early research and the psychological processes being studied.

  10. Ground based simulation of life sciences Spacelab experiments

    NASA Technical Reports Server (NTRS)

    Rummel, J. A.; Alexander, W. C.; Bush, W. H.; Johnston, R. S.

    1978-01-01

    The third in a series of Spacelab Mission Development tests was a joint effort of the Ames Research and Johnson Space Centers to evaluate planned operational concepts of the Space Shuttle life sciences program. A three-man crew conducted 26 experiments and 12 operational tests, utilizing both human and animal subjects. The crew lived aboard an Orbiter/Spacelab mockup for the seven-day simulation. The Spacelab was identical in geometry to the European Space Agency design, complete with removable rack sections and stowage provisions. Communications were controlled as currently planned for operational Shuttle flights. A Science Operations Remote Center at the Ames Research Center was managed by simulated Mission Control and Payload Operation Control Centers at the Johnson Space Center. This paper presents the test objectives, describes the facilities and test program, and outlines the results of this test.

  11. Simulation of Spacecraft Damage Tolerance and Adaptive Controls

    DTIC Science & Technology

    2013-06-01

    operator. Limitations of current technology abounded, leaving the X-15 with a successful, but severely limited adaptive control system. Since then...many limitations have fallen away, allowing for the first time employment of adaptive controls on a large scale. The nature of adaptive controls, or...THIS PAGE Unclassified 19. SECURITY CLASSIFICATION OF ABSTRACT Unclassified 20. LIMITATION OF ABSTRACT UU NSN 7540–01–280–5500 Standard Form

  12. The tug-of-war: fidelity versus adaptation throughout the health promotion program life cycle.

    PubMed

    Bopp, Melissa; Saunders, Ruth P; Lattimore, Diana

    2013-06-01

    Researchers across multiple fields have described the iterative and nonlinear phases of the translational research process from program development to dissemination. This process can be conceptualized within a "program life cycle" framework that includes overlapping and nonlinear phases: development, adoption, implementation, maintenance, sustainability or termination, and dissemination or diffusion, characterized by tensions between fidelity to the original plan and adaptation for the setting and population. In this article, we describe the life cycle (phases) for research-based health promotion programs, the key influences at each phase, and the issues related to the tug-of-war between fidelity and adaptation throughout the process using a fictionalized case study based on our previous research. This article suggests the importance of reconceptualizing intervention design, involving stakeholders, and monitoring fidelity and adaptation throughout all phases to maintain implementation fidelity and completeness. Intervention fidelity should be based on causal mechanisms to ensure effectiveness, while allowing for appropriate adaption to ensure maximum implementation and sustainability. Recommendations for future interventions include considering the determinants of implementation including contextual factors at each phase, the roles of stakeholders, and the importance of developing a rigorous, adaptive, and flexible definition of implementation fidelity and completeness.

  13. Fetal programming: adaptive life-history tactics or making the best of a bad start?

    PubMed

    Jones, James Holland

    2005-01-01

    Fetal programming is an ontogenetic phenomenon of increasing interest to human biologists. Because the downstream consequences of fetal programming have clear impacts on specific life-history traits (e.g., age at first reproduction and the general age-pattern of reproductive investments), a number of authors have raised the question of the adaptive significance of fetal programming. In this paper, I review in some detail several classical models in life-history theory and discuss their relative merits and weaknesses for human biology. I suggest that an adequate model of human life-history evolution must account for the highly structured nature of the human life cycle, with its late age at first reproduction, large degree of iteroparity, highly overlapping generations, and extensive, post-weaning parental investment. I further suggest that an understanding of stochastic demography is essential for answering the question of the adaptive significance of fetal programming, and specifically the finding of low birth weight on smaller adult body size and earlier age at first reproduction. Using a stage-structured stochastic population model, I show that the downstream consequences of early deprivation may be "making the best of a bad start" rather than an adaptation per se. When a high-investment strategy entails survival costs, the alternate strategy of early reproduction with relatively low investment may have higher fitness than trying to play the high-investment strategy and failing.

  14. Adaptive Training Considerations for Use in Simulation-Based Systems

    DTIC Science & Technology

    2010-09-01

    ABSTRACT In this report, we examine theoretical and empirical papers that describe adaptive training (AT). When applied effectively, AT has the...the effectiveness of various instructional techniques and methods. In the current report, we examine theoretical and empirical papers that describe...this report, we examine theoretical and empirical papers that describe one such advanced training method, Adaptive Training (AT). In AT, some

  15. Visual Simulation of Microalgae Growth in Bioregenerative Life Support System

    NASA Astrophysics Data System (ADS)

    Zhao, Ming

    Bioregenerative life support system is one of the key technologies for future human deep space exploration and long-term space missions. BLSS use biological system as its core unit in combination with other physical and chemical equipments, under the proper control and manipulation by crew to complete a specific task to support life. Food production, waste treatment, oxygen and water regeneration are all conducted by higher plants or microalgae in BLSS, which is the most import characteristic different from other kinds of life support systems. Microalgae is light autotrophic micro-organisms, light undoubtedly is the most import factor which limits its growth and reproduction. Increasing or decreasing the light intensity changes the growth rate of microalgae, and then regulates the concentration of oxygen and carbon dioxide in the system. In this paper, based on the mathematical model of microalgae which grew under the different light intensity, three-dimensional visualization model was built and realized through using 3ds max, Virtools and some other three dimensional software, in order to display its change and impacting on oxygen and carbon dioxide intuitively. We changed its model structure and parameters, such as establishing closed-loop control system, light intensity, temperature and Nutrient fluid’s velocity and so on, carried out computer virtual simulation, and observed dynamic change of system with the aim of providing visualization support for system research.

  16. International Space Station Environmental Control and Life Support System Acceptance Testing for the Pressurized Mating Adapters

    NASA Technical Reports Server (NTRS)

    Williams, David E.

    2008-01-01

    The International Space Station (ISS) Pressurized Mating Adapters (PMAs) Environmental Control and Life Support (ECLS) System is comprised of three subsystems: Atmosphere Control and Supply (ACS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). PMAs 1 and 2 flew to ISS on Flight 2A and Pressurized Mating Adapter (PMA) 3 flew to ISS on Flight 3A. This paper provides a summary of the PMAs ECLS design and a detailed discussion of the ISS ECLS Acceptance Testing methodologies utilized for the PMAs.

  17. Health-related quality of life and adaptive behaviors of adolescents with sickle cell disease: stress processing moderators.

    PubMed

    Ziadni, Maisa S; Patterson, Chavis A; Pulgarón, Elizabeth R; Robinson, M Renée; Barakat, Lamia P

    2011-12-01

    The objective of this study was to examine resilience among adolescents with sickle cell disease (SCD), focusing on the interaction of health-related quality of life with stress processing to explain adaptive behavior. Forty-four adolescents with SCD completed paper-and-pencil measures of health-related quality of life, appraisals (hope), pain coping strategies (e.g. adherence), and adaptive behavior. Self-reported health-related quality of life was significantly associated with adaptive behavior, as was adherence. Findings for moderation were mixed. Pain coping strategies moderated the association of health-related quality of life with adaptive behavior such that at lower levels of Coping Strategies Questionnaire (CSQ) Adherence, better quality of life was associated with higher adaptive behavior. Similarly, at higher levels of hope, better quality of life was associated with higher adaptive behavior, and poorer quality of life was associated with lower adaptive behavior. Adolescents with SCD showed resilience, particularly in terms of personal adjustment, that may be explained by their appraisals and stress processing strategies. Interventions to support an optimistic or hopeful outlook and improve adherence to recommendations for medical management of sickle cell pain may result in improved resilience/adaptive behavior.

  18. Quantum simulations of nuclei and nuclear pasta with the multiresolution adaptive numerical environment for scientific simulations

    NASA Astrophysics Data System (ADS)

    Sagert, I.; Fann, G. I.; Fattoyev, F. J.; Postnikov, S.; Horowitz, C. J.

    2016-05-01

    Background: Neutron star and supernova matter at densities just below the nuclear matter saturation density is expected to form a lattice of exotic shapes. These so-called nuclear pasta phases are caused by Coulomb frustration. Their elastic and transport properties are believed to play an important role for thermal and magnetic field evolution, rotation, and oscillation of neutron stars. Furthermore, they can impact neutrino opacities in core-collapse supernovae. Purpose: In this work, we present proof-of-principle three-dimensional (3D) Skyrme Hartree-Fock (SHF) simulations of nuclear pasta with the Multi-resolution ADaptive Numerical Environment for Scientific Simulations (MADNESS). Methods: We perform benchmark studies of 16O, 208Pb, and 238U nuclear ground states and calculate binding energies via 3D SHF simulations. Results are compared with experimentally measured binding energies as well as with theoretically predicted values from an established SHF code. The nuclear pasta simulation is initialized in the so-called waffle geometry as obtained by the Indiana University Molecular Dynamics (IUMD) code. The size of the unit cell is 24 fm with an average density of about ρ =0.05 fm-3 , proton fraction of Yp=0.3 , and temperature of T =0 MeV. Results: Our calculations reproduce the binding energies and shapes of light and heavy nuclei with different geometries. For the pasta simulation, we find that the final geometry is very similar to the initial waffle state. We compare calculations with and without spin-orbit forces. We find that while subtle differences are present, the pasta phase remains in the waffle geometry. Conclusions: Within the MADNESS framework, we can successfully perform calculations of inhomogeneous nuclear matter. By using pasta configurations from IUMD it is possible to explore different geometries and test the impact of self-consistent calculations on the latter.

  19. Early-Life Stress, HPA Axis Adaptation, and Mechanisms Contributing to Later Health Outcomes

    PubMed Central

    Maniam, Jayanthi; Antoniadis, Christopher; Morris, Margaret J.

    2014-01-01

    Stress activates the hypothalamic–pituitary–adrenal (HPA) axis, which then modulates the degree of adaptation and response to a later stressor. It is known that early-life stress can impact on later health but less is known about how early-life stress impairs HPA axis activity, contributing to maladaptation of the stress–response system. Early-life stress exposure (either prenatally or in the early postnatal period) can impact developmental pathways resulting in lasting structural and regulatory changes that predispose to adulthood disease. Epidemiological, clinical, and experimental studies have demonstrated that early-life stress produces long term hyper-responsiveness to stress with exaggerated circulating glucocorticoids, and enhanced anxiety and depression-like behaviors. Recently, evidence has emerged on early-life stress-induced metabolic derangements, for example hyperinsulinemia and altered insulin sensitivity on exposure to a high energy diet later in life. This draws our attention to the contribution of later environment to disease vulnerability. Early-life stress can alter the expression of genes in peripheral tissues, such as the glucocorticoid receptor and 11-beta hydroxysteroid dehydrogenase (11β-HSD1). We propose that interactions between altered HPA axis activity and liver 11β-HSD1 modulates both tissue and circulating glucocorticoid availability, with adverse metabolic consequences. This review discusses the potential mechanisms underlying early-life stress-induced maladaptation of the HPA axis, and its subsequent effects on energy utilization and expenditure. The effects of positive later environments as a means of ameliorating early-life stress-induced health deficits, and proposed mechanisms underpinning the interaction between early-life stress and subsequent detrimental environmental exposures on metabolic risk will be outlined. Limitations in current methodology linking early-life stress and later health outcomes will also be

  20. Emergent adaptive behaviour of GRN-controlled simulated robots in a changing environment.

    PubMed

    Yao, Yao; Storme, Veronique; Marchal, Kathleen; Van de Peer, Yves

    2016-01-01

    We developed a bio-inspired robot controller combining an artificial genome with an agent-based control system. The genome encodes a gene regulatory network (GRN) that is switched on by environmental cues and, following the rules of transcriptional regulation, provides output signals to actuators. Whereas the genome represents the full encoding of the transcriptional network, the agent-based system mimics the active regulatory network and signal transduction system also present in naturally occurring biological systems. Using such a design that separates the static from the conditionally active part of the gene regulatory network contributes to a better general adaptive behaviour. Here, we have explored the potential of our platform with respect to the evolution of adaptive behaviour, such as preying when food becomes scarce, in a complex and changing environment and show through simulations of swarm robots in an A-life environment that evolution of collective behaviour likely can be attributed to bio-inspired evolutionary processes acting at different levels, from the gene and the genome to the individual robot and robot population.

  1. Emergent adaptive behaviour of GRN-controlled simulated robots in a changing environment

    PubMed Central

    Yao, Yao; Storme, Veronique; Marchal, Kathleen

    2016-01-01

    We developed a bio-inspired robot controller combining an artificial genome with an agent-based control system. The genome encodes a gene regulatory network (GRN) that is switched on by environmental cues and, following the rules of transcriptional regulation, provides output signals to actuators. Whereas the genome represents the full encoding of the transcriptional network, the agent-based system mimics the active regulatory network and signal transduction system also present in naturally occurring biological systems. Using such a design that separates the static from the conditionally active part of the gene regulatory network contributes to a better general adaptive behaviour. Here, we have explored the potential of our platform with respect to the evolution of adaptive behaviour, such as preying when food becomes scarce, in a complex and changing environment and show through simulations of swarm robots in an A-life environment that evolution of collective behaviour likely can be attributed to bio-inspired evolutionary processes acting at different levels, from the gene and the genome to the individual robot and robot population. PMID:28028477

  2. Adaptive resolution simulation of liquid para-hydrogen: testing the robustness of the quantum-classical adaptive coupling.

    PubMed

    Poma, A B; Delle Site, L

    2011-06-14

    Adaptive resolution simulations for classical systems are currently made within a reasonably consistent theoretical framework. Recently we have extended this approach to the quantum-classical coupling by mapping the quantum nature of an atom onto a classical polymer ring representation within the path integral approach [Poma & Delle Site, Phys. Rev. Lett., 2010, 104, 250201]. In this way the process of interfacing adaptively a quantum representation to a classical one corresponds to the problem of interfacing two regions with a different number of effective "classical" degrees of freedom; thus the classical formulation of the adaptive algorithm applies straightforwardly to the quantum-classical problem. In this work we show the robustness of such an approach for a liquid of para-hydrogen at low temperature. This system represents a highly challenging conceptual and technical test for the adaptive approach due to the extreme thermodynamical conditions where quantum effects play a central role.

  3. Pilot Evaluation of Adaptive Control in Motion-Based Flight Simulator

    NASA Technical Reports Server (NTRS)

    Kaneshige, John T.; Campbell, Stefan Forrest

    2009-01-01

    The objective of this work is to assess the strengths, weaknesses, and robustness characteristics of several MRAC (Model-Reference Adaptive Control) based adaptive control technologies garnering interest from the community as a whole. To facilitate this, a control study using piloted and unpiloted simulations to evaluate sensitivities and handling qualities was conducted. The adaptive control technologies under consideration were ALR (Adaptive Loop Recovery), BLS (Bounded Linear Stability), Hybrid Adaptive Control, L1, OCM (Optimal Control Modification), PMRAC (Predictor-based MRAC), and traditional MRAC

  4. International Space Station Environmental Control and Life Support System: Verification for the Pressurized Mating Adapters

    NASA Technical Reports Server (NTRS)

    Williams, David E.

    2007-01-01

    The International Space Station (ISS) Pressurized Mating Adapters (PMAs) Environmental Control and Life Support (ECLS) System is comprised of three subsystems: Atmosphere Control and Supply (ACS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). PMA 1 and PMA 2 flew to ISS on Flight 2A and PMA 3 flew to ISS on Flight 3A. This paper provides a summary of the PMAs ECLS design and the detailed Element Verification methodologies utilized during the Qualification phase for the PMAs.

  5. Materials learning from life: concepts for active, adaptive and autonomous molecular systems.

    PubMed

    Merindol, Rémi; Walther, Andreas

    2017-01-30

    Bioinspired out-of-equilibrium systems will set the scene for the next generation of molecular materials with active, adaptive, autonomous, emergent and intelligent behavior. Indeed life provides the best demonstrations of complex and functional out-of-equilibrium systems: cells keep track of time, communicate, move, adapt, evolve and replicate continuously. Stirred by the understanding of biological principles, artificial out-of-equilibrium systems are emerging in many fields of soft matter science. Here we put in perspective the molecular mechanisms driving biological functions with the ones driving synthetic molecular systems. Focusing on principles that enable new levels of functionalities (temporal control, autonomous structures, motion and work generation, information processing) rather than on specific material classes, we outline key cross-disciplinary concepts that emerge in this challenging field. Ultimately, the goal is to inspire and support new generations of autonomous and adaptive molecular devices fueled by self-regulating chemistry.

  6. Cultural adaptation and validation of the Freiburg Life Quality Assessment - Wound Module to Brazilian Portuguese1

    PubMed Central

    Domingues, Elaine Aparecida Rocha; Alexandre, Neusa Maria Costa; da Silva, José Vitor

    2016-01-01

    Objectives: to adapt the Freiburg Life Quality Assessment - Wound Module to Brazilian Portuguese and to measure its psychometric properties: reliability and validity. Method: the cultural adaptation was undertaken following the stages of translation, synthesis of the translations, back translation, committee of specialists, pre-test and focus group. A total of 200 patients participated in the study. These were recruited in Primary Care Centers, Family Health Strategy Centers, in a philanthropic hospital and in a teaching hospital. Reliability was assessed through internal consistency and stability. Validity was ascertained through the correlation of the instrument's values with those of the domains of the Ferrans and Powers Quality of Life Index - Wound Version and with the quality of life score of the visual analog scale. Results: the instrument presented adequate internal consistency (Cronbach alpha =0.86) and high stability in the test and retest (0.93). The validity presented correlations of moderate and significant magnitude (-0.24 to -0.48, p<0.0001). Conclusion: the results indicated that the adapted version presented reliable and valid psychometric measurements for the population with chronic wounds in the Brazilian culture. PMID:27143539

  7. Mass balances for a biological life support system simulation model

    NASA Technical Reports Server (NTRS)

    Volk, Tyler; Rummel, John D.

    1987-01-01

    Design decisions to aid the development of future space based biological life support systems (BLSS) can be made with simulation models. The biochemistry stoichiometry was developed for: (1) protein, carbohydrate, fat, fiber, and lignin production in the edible and inedible parts of plants; (2) food consumption and production of organic solids in urine, feces, and wash water by the humans; and (3) operation of the waste processor. Flux values for all components are derived for a steady state system with wheat as the sole food source. The large scale dynamics of a materially closed (BLSS) computer model is described in a companion paper. An extension of this methodology can explore multifood systems and more complex biochemical dynamics while maintaining whole system closure as a focus.

  8. A modular BLSS simulation model. [Bioregenerative Life Support System

    NASA Technical Reports Server (NTRS)

    Rummel, John D.; Volk, Tyler

    1987-01-01

    The coordination of material flows in earth's biosphere is largely made possible by the buffering effect of huge material reservoirs. Without similarly-sized buffers, a bioregenerative life support system (BLSS) for extraterrestrial use will be faced with coordination problems more acute than those in any ecosystem found on earth. A related problem in BLSS design is providing an interface between the various life-support processors, one that will allow for their coordination while still allowing for system expansion. A modular model is presented of a BLSS that interfaces system processors only with the material storage reservoirs, allowing those reservoirs to act as the principal buffers in the system and thus minimizing difficulties with processor coordination. The modular nature of the model allows independent development of the detailed submodels that exist within the model framework. Using this model, BLSS dynamics were investigated under normal conditions and under various failure modes. Partial and complete failures of various components, such as the waste processor or the plants themselves, drive transient responses in the model system, allowing examination of the effectiveness of the system reservoirs as buffers. The results from simulations of this sort will help to determine control strategies and BLSS design requirements. An evolved version of this model could be used as an interactive control aid in a future BLSS.

  9. Simulation and Experiment of Extinction or Adaptation of Biological Species after Temperature Changes

    NASA Astrophysics Data System (ADS)

    Stauffer, D.; Arndt, H.

    Can unicellular organisms survive a drastic temperature change, and adapt to it after many generations? In simulations of the Penna model of biological aging, both extinction and adaptation were found for asexual and sexual reproduction as well as for parasex. These model investigations are the basis for the design of evolution experiments with heterotrophic flagellates.

  10. Rhythmic life of the Arctic charr: adaptations to life at the edge.

    PubMed

    Jørgensen, Even Hjalmar; Johnsen, Helge Kreutzer

    2014-04-01

    High latitudes are characterized by strong seasonal changes in environmental conditions, including temperature and food availability. To cope with these changes, many high latitude species have developed circannual oscillators that enable them to anticipate and prepare for forthcoming environmental changes and synchronize seasonal events (e.g. reproduction) to environmental fluctuations. The Arctic charr (Salvelinus alpinus) is the world's northernmost freshwater fish species with a distribution largely confined within the Arctic. In the northernmost part of its distribution they have developed an anadromous life-history strategy implying annual, seaward migrations in the summer to utilize the rich feeding opportunity in the sea. Overwintering in freshwater is characterized by anorexia and energy conservation. The seaward migration in early summer is preceded by physiological and behavioral changes (smolting), by which they develop seawater tolerance (hypoosmoregulatory ability) and migratory behavior. When migrating to the sea, Arctic charr have regained a strong appetite and within 4-6weeks in the sea they may have doubled their body weight and increased their body fat stores several-fold, in anticipation of the resources needed for reproduction in the autumn and overwintering. All these processes are regulated independently of environmental changes; captive offspring of anadromous charr kept in freshwater displays seasonal changes in seawater tolerance and strong seasonal changes in food intake and growth even when they are continuously fed in excess and held at a constant water temperature in freshwater. A correct timing of these events is crucial for their survival in the Arctic and the Arctic charr seems to possess timing mechanisms that include endogenous, circannual oscillator(s) entrainable by photoperiod. The entrainment mechanism may be linked to diel melatonin rhythms, which in this species exactly mirror overground photoperiod, even during the winter

  11. Development of Multi-Adaptive Simulation Technologies for Nonlinear Solid Polymer Viscoelasticity

    DTIC Science & Technology

    2007-10-31

    2007 4. TITLE AND SUBTITLE Development of multi-adaptive simulation technologies for nonlinear solid polymer viscoelasticity 6. AUTHOR(S) J.R. Whiteman...Close out report (funding period 1 April 2007 – 31 July 2007) Development of multi-adaptive simulation technologies for nonlinear solid polymer ...equations describing the inflation of a hyperelastic membrane. With U denoting the exact displacement and V denoting the exact velocity the weak forms

  12. Adaptive grids and implicit differencing applied to plasma simulation

    SciTech Connect

    Brackbill, J.U.; Forslund, D.W.; Vu, Hoanh.

    1990-01-01

    To understand the kinetic processes that determine energy confinement and impurity production in magnetic confinement experiments, we are developing methods to model kinetic effects on magnetohydrodynamic time scales in realistic geometries. We are using implicit methods and adaptive grids to achieve this goal. 9 refs., 2 figs.

  13. Multiple Model Parameter Adaptive Control for In-Flight Simulation.

    DTIC Science & Technology

    1988-03-01

    dynamics of an aircraft. The plant is control- lable by a proportional-plus-integral ( PI ) control law. This section describes two methods of calculating...adaptive model-following PI control law [20-24]. The control law bases its control gains upon the parameters of a linear difference equation model which

  14. The New England Climate Adaptation Project: Enhancing Local Readiness to Adapt to Climate Change through Role-Play Simulations

    NASA Astrophysics Data System (ADS)

    Rumore, D.; Kirshen, P. H.; Susskind, L.

    2014-12-01

    Despite scientific consensus that the climate is changing, local efforts to prepare for and manage climate change risks remain limited. How we can raise concern about climate change risks and enhance local readiness to adapt to climate change's effects? In this presentation, we will share the lessons learned from the New England Climate Adaptation Project (NECAP), a participatory action research project that tested science-based role-play simulations as a tool for educating the public about climate change risks and simulating collective risk management efforts. NECAP was a 2-year effort involving the Massachusetts Institute of Technology, the Consensus Building Institute, the National Estuarine Research Reserve System, and four coastal New England municipalities. During 2012-2013, the NECAP team produced downscaled climate change projections, a summary risk assessment, and a stakeholder assessment for each partner community. Working with local partners, we used these assessments to create a tailored, science-based role-play simulation for each site. Through a series of workshops in 2013, NECAP engaged between 115-170 diverse stakeholders and members of the public in each partner municipality in playing the simulation and a follow up conversation about local climate change risks and possible adaptation strategies. Data were collected through before-and-after surveys administered to all workshop participants, follow-up interviews with 25 percent of workshop participants, public opinion polls conducted before and after our intervention, and meetings with public officials. This presentation will report our research findings and explain how science-based role-play simulations can be used to help communicate local climate change risks and enhance local readiness to adapt.

  15. Implementation and Evaluation of Multiple Adaptive Control Technologies for a Generic Transport Aircraft Simulation

    NASA Technical Reports Server (NTRS)

    Campbell, Stefan F.; Kaneshige, John T.; Nguyen, Nhan T.; Krishakumar, Kalmanje S.

    2010-01-01

    Presented here is the evaluation of multiple adaptive control technologies for a generic transport aircraft simulation. For this study, seven model reference adaptive control (MRAC) based technologies were considered. Each technology was integrated into an identical dynamic-inversion control architecture and tuned using a methodology based on metrics and specific design requirements. Simulation tests were then performed to evaluate each technology s sensitivity to time-delay, flight condition, model uncertainty, and artificially induced cross-coupling. The resulting robustness and performance characteristics were used to identify potential strengths, weaknesses, and integration challenges of the individual adaptive control technologies

  16. Hot tadpoles from cold environments need more nutrients--life history and stoichiometry reflects latitudinal adaptation.

    PubMed

    Liess, Antonia; Rowe, Owen; Guo, Junwen; Thomsson, Gustaf; Lind, Martin I

    2013-11-01

    1. High-latitude species (and populations within species) are adapted to short and cold summers. They often have high growth and development rates to fully use the short growing season and mature before the onset of winter. 2. Within the context of ecological stoichiometry theory, this study combines ecology with evolution by relating latitudinal life-history adaptations to their molecular consequences in body nutrient composition in Rana temporaria tadpoles. 3. Temperature and food quality were manipulated during the development of tadpoles from Arctic and Boreal origins. We determined tadpole growth rate, development rate, body size and nutrient content, to test whether (i) Arctic tadpoles could realize higher growth rates and development rates with the help of higher-quality food even when food quantity was unchanged, (ii) Arctic and Boreal tadpoles differed in their stoichiometric (and life history) response to temperature changes, (iii) higher growth rates lead to higher tadpole P content (growth rate hypothesis) and (iv) allometric scaling affects tadpole nutrient allocation. 4. We found that especially Arctic tadpoles grew and developed faster with the help of higher-quality food and that tadpoles differed in their stoichiometric (and life history) response to temperature changes depending on region of origin (probably due to different temperature optima). There was no evidence that higher growth rates mediated the positive effect of temperature on tadpole P content. On the contrary, the covariate growth rate was negatively connected with tadpole P content (refuting the growth rate hypothesis). Lastly, tadpole P content was not related to body size, but tadpole C content was higher in larger tadpoles, probably due to increased fat storage. 5. We conclude that temperature had a strong effect on tadpole life history, nutrient demand and stoichiometry and that this effect depended on the evolved life history.

  17. A new adaptive time step method for unsteady flow simulations in a human lung.

    PubMed

    Fenández-Tena, Ana; Marcos, Alfonso C; Martínez, Cristina; Keith Walters, D

    2017-04-07

    The innovation presented is a method for adaptive time-stepping that allows clustering of time steps in portions of the cycle for which flow variables are rapidly changing, based on the concept of using a uniform step in a relevant dependent variable rather than a uniform step in the independent variable time. A user-defined function was developed to adapt the magnitude of the time step (adaptive time step) to a defined rate of change in inlet velocity. Quantitative comparison indicates that the new adaptive time stepping method significantly improves accuracy for simulations using an equivalent number of time steps per cycle.

  18. Simulation Experiments with Goal-Seeking Adaptive Elements.

    DTIC Science & Technology

    1984-02-01

    when it comes to cognition and particularly bad when it comes to remote sensing, goal seeking, adaptation and decision making, where brains excel. In...Erlbaum 1981, 161-187 Hinton, G. E., & Sejnowski, T. J. Analyzing Cooperative Computation. Proceedings of the Fifth Annual Conference of the Cognitive ...Algorithms and Applications. Springer-Verlag, 1981. Lenat, D. B., Hayes-Roth, F., Klahr, P. Cognitive economy. Stanford Heuristic Program- ming Project HPP

  19. Fuzzy Backstepping Torque Control Of Passive Torque Simulator With Algebraic Parameters Adaptation

    NASA Astrophysics Data System (ADS)

    Ullah, Nasim; Wang, Shaoping; Wang, Xingjian

    2015-07-01

    This work presents fuzzy backstepping control techniques applied to the load simulator for good tracking performance in presence of extra torque, and nonlinear friction effects. Assuming that the parameters of the system are uncertain and bounded, Algebraic parameters adaptation algorithm is used to adopt the unknown parameters. The effect of transient fuzzy estimation error on parameters adaptation algorithm is analyzed and the fuzzy estimation error is further compensated using saturation function based adaptive control law working in parallel with the actual system to improve the transient performance of closed loop system. The saturation function based adaptive control term is large in the transient time and settles to an optimal lower value in the steady state for which the closed loop system remains stable. The simulation results verify the validity of the proposed control method applied to the complex aerodynamics passive load simulator.

  20. Wavelet-Based Adaptive Solvers on Multi-core Architectures for the Simulation of Complex Systems

    NASA Astrophysics Data System (ADS)

    Rossinelli, Diego; Bergdorf, Michael; Hejazialhosseini, Babak; Koumoutsakos, Petros

    We build wavelet-based adaptive numerical methods for the simulation of advection dominated flows that develop multiple spatial scales, with an emphasis on fluid mechanics problems. Wavelet based adaptivity is inherently sequential and in this work we demonstrate that these numerical methods can be implemented in software that is capable of harnessing the capabilities of multi-core architectures while maintaining their computational efficiency. Recent designs in frameworks for multi-core software development allow us to rethink parallelism as task-based, where parallel tasks are specified and automatically mapped into physical threads. This way of exposing parallelism enables the parallelization of algorithms that were considered inherently sequential, such as wavelet-based adaptive simulations. In this paper we present a framework that combines wavelet-based adaptivity with the task-based parallelism. We demonstrate good scaling performance obtained by simulating diverse physical systems on different multi-core and SMP architectures using up to 16 cores.

  1. Cosmic radiation and evolution of life on earth: Roles of environment, adaptation and selection

    NASA Astrophysics Data System (ADS)

    Todd, P.

    1994-10-01

    The role of ionizing radiation in general, and cosmic radiation in particular, in the evolution of organisms on the earth by adaptation and natural selection is considered in a series of questions: (1) Are there times during the evolution of the earth and of life when genetic material could be exposed to heavy ion radiation? (2) Throughout the course of chemical and biological evolution on the earth, what fraction of environmental mutagenesis could be attributable to cosmic and/or solar ionizing radiation? (3) Is ionizing radiation an agent of adaptation or selection, or both? (4) What can the cladistics of the evolution of genetic repair tell us about the global history of genotoxic selection pressures? (How much genetic diversity can be attributed to the selection of radiation-damage repair processes?

  2. Time-and-Spatially Adapting Simulations for Efficient Dynamic Stall Predictions

    DTIC Science & Technology

    2015-09-01

    SIMULATIONS FOR EFFICIENTDYNAMIC STALL PREDICTIONS The ability to accurately and efficiently predict the occurrence and severity of dynamic stall...The ability to accurately and efficiently predict the occurrence and severity of dynamic stall remains a major roadblock in the design and analysis...SPATIALLY ADAPTING SIMULATIONS FOR EFFICIENT DYNAMIC STALL PREDICTIONS Marilyn J. Smith Professor Georgia Tech Rohit Jain Aerospace Engineer US Army

  3. Deriving comprehensive error breakdown for wide field adaptive optics systems using end-to-end simulations

    NASA Astrophysics Data System (ADS)

    Ferreira, F.; Gendron, E.; Rousset, G.; Gratadour, D.

    2016-07-01

    The future European Extremely Large Telescope (E-ELT) adaptive optics (AO) systems will aim at wide field correction and large sky coverage. Their performance will be improved by using post processing techniques, such as point spread function (PSF) deconvolution. The PSF estimation involves characterization of the different error sources in the AO system. Such error contributors are difficult to estimate: simulation tools are a good way to do that. We have developed in COMPASS (COMputing Platform for Adaptive opticS Systems), an end-to-end simulation tool using GPU (Graphics Processing Unit) acceleration, an estimation tool that provides a comprehensive error budget by the outputs of a single simulation run.

  4. Applying Parallel Adaptive Methods with GeoFEST/PYRAMID to Simulate Earth Surface Crustal Dynamics

    NASA Technical Reports Server (NTRS)

    Norton, Charles D.; Lyzenga, Greg; Parker, Jay; Glasscoe, Margaret; Donnellan, Andrea; Li, Peggy

    2006-01-01

    This viewgraph presentation reviews the use Adaptive Mesh Refinement (AMR) in simulating the Crustal Dynamics of Earth's Surface. AMR simultaneously improves solution quality, time to solution, and computer memory requirements when compared to generating/running on a globally fine mesh. The use of AMR in simulating the dynamics of the Earth's Surface is spurred by future proposed NASA missions, such as InSAR for Earth surface deformation and other measurements. These missions will require support for large-scale adaptive numerical methods using AMR to model observations. AMR was chosen because it has been successful in computation fluid dynamics for predictive simulation of complex flows around complex structures.

  5. Cartesian Off-Body Grid Adaption for Viscous Time- Accurate Flow Simulation

    NASA Technical Reports Server (NTRS)

    Buning, Pieter G.; Pulliam, Thomas H.

    2011-01-01

    An improved solution adaption capability has been implemented in the OVERFLOW overset grid CFD code. Building on the Cartesian off-body approach inherent in OVERFLOW and the original adaptive refinement method developed by Meakin, the new scheme provides for automated creation of multiple levels of finer Cartesian grids. Refinement can be based on the undivided second-difference of the flow solution variables, or on a specific flow quantity such as vorticity. Coupled with load-balancing and an inmemory solution interpolation procedure, the adaption process provides very good performance for time-accurate simulations on parallel compute platforms. A method of using refined, thin body-fitted grids combined with adaption in the off-body grids is presented, which maximizes the part of the domain subject to adaption. Two- and three-dimensional examples are used to illustrate the effectiveness and performance of the adaption scheme.

  6. Safety simulation model for drivers of adapted cars

    NASA Astrophysics Data System (ADS)

    Eixerés, B.; Masiá, J.; Dols, J. F.; Colomina, F. J.

    2009-11-01

    In cases where frontal impacts take place in vehicles in which control devices have been mounted, driver safety is compromised by the effect of these devices on the correct working of the driver airbag [1]. The simulation provided information on the forces involved in the injuries sustained by the driver. In this simulation, the crash survival space is based on a frontal impact. On one hand, there is a passive set of forces generated by the steering control device and the steering wheel. On the other hand, there are the forces generated by the airbag. An airbag model was used, formed by a fabric bag which is correctly folded, and filled with a gas that expands according to a theoretical model. In this simulation, a dummy is also added to represent the driver, who is correctly secured with the safety belt. These elements are subjected to decelerations corresponding to a frontal impact. This work analyzes what happens during these impacts.

  7. Genome analysis of three Pneumocystis species reveals adaptation mechanisms to life exclusively in mammalian hosts

    PubMed Central

    Ma, Liang; Chen, Zehua; Huang, Da Wei; Kutty, Geetha; Ishihara, Mayumi; Wang, Honghui; Abouelleil, Amr; Bishop, Lisa; Davey, Emma; Deng, Rebecca; Deng, Xilong; Fan, Lin; Fantoni, Giovanna; Fitzgerald, Michael; Gogineni, Emile; Goldberg, Jonathan M.; Handley, Grace; Hu, Xiaojun; Huber, Charles; Jiao, Xiaoli; Jones, Kristine; Levin, Joshua Z.; Liu, Yueqin; Macdonald, Pendexter; Melnikov, Alexandre; Raley, Castle; Sassi, Monica; Sherman, Brad T.; Song, Xiaohong; Sykes, Sean; Tran, Bao; Walsh, Laura; Xia, Yun; Yang, Jun; Young, Sarah; Zeng, Qiandong; Zheng, Xin; Stephens, Robert; Nusbaum, Chad; Birren, Bruce W.; Azadi, Parastoo; Lempicki, Richard A.; Cuomo, Christina A.; Kovacs, Joseph A.

    2016-01-01

    Pneumocystis jirovecii is a major cause of life-threatening pneumonia in immunosuppressed patients including transplant recipients and those with HIV/AIDS, yet surprisingly little is known about the biology of this fungal pathogen. Here we report near complete genome assemblies for three Pneumocystis species that infect humans, rats and mice. Pneumocystis genomes are highly compact relative to other fungi, with substantial reductions of ribosomal RNA genes, transporters, transcription factors and many metabolic pathways, but contain expansions of surface proteins, especially a unique and complex surface glycoprotein superfamily, as well as proteases and RNA processing proteins. Unexpectedly, the key fungal cell wall components chitin and outer chain N-mannans are absent, based on genome content and experimental validation. Our findings suggest that Pneumocystis has developed unique mechanisms of adaptation to life exclusively in mammalian hosts, including dependence on the lungs for gas and nutrients and highly efficient strategies to escape both host innate and acquired immune defenses. PMID:26899007

  8. The Cultural Adaptation of the Youth Quality of Life Instrument-Research Version for Latino Children and Adolescents

    ERIC Educational Resources Information Center

    Chavez, Ligia M.; Matias-Carrelo, Leida; Barrio, Concepcion; Canino, Glorisa

    2007-01-01

    We reviewed the Spanish translation of the Youth Quality of Life Instrument-Research Version (YQOL-R) and culturally adapted the measure with Puerto Rican and Mexican American children and adolescents. The YQOL-R is a self-reported measure that includes four domains: Sense of Self, Social Relationships, Environment, and General Quality of Life. A…

  9. The Cultural Adaptation Process of Agricultural and Life Sciences Students on Short-Term Study Abroad Experiences

    ERIC Educational Resources Information Center

    Conner, Nathan William

    2013-01-01

    The purpose of this study was to explore how undergraduate students in a college of agricultural and life sciences experienced cultural adaptation during short-term study abroad programs. The specific objectives of this study were to describe how undergraduate students in the college of agricultural and life sciences experienced culture throughout…

  10. The roles of life-history selection and sexual selection in the adaptive evolution of mating behavior in a beetle.

    PubMed

    Maklakov, Alexei A; Cayetano, Luis; Brooks, Robert C; Bonduriansky, Russell

    2010-05-01

    Although there is continuing debate about whether sexual selection promotes or impedes adaptation to novel environments, the role of mating behavior in such adaptation remains largely unexplored. We investigated the evolution of mating behavior (latency to mating, mating probability and duration) in replicate populations of seed beetles Callosobruchus maculatus subjected to selection on life-history ("Young" vs. "Old" reproduction) under contrasting regimes of sexual selection ("Monogamy" vs. "Polygamy"). Life-history selection is predicted to favor delayed mating in "Old" females, but sexual conflict under polygamy can potentially retard adaptive life-history evolution. We found that life-history selection yielded the predicted changes in mating behavior, but sexual selection regime had no net effect. In within-line crosses, populations selected for late reproduction showed equally reduced early-life mating probability regardless of mating system. In between-line crosses, however, the effect of life-history selection on early-life mating probability was stronger in polygamous lines than in monogamous ones. Thus, although mating system influenced male-female coevolution, removal of sexual selection did not affect the adaptive evolution of mating behavior. Importantly, our study shows that the interaction between sexual selection and life-history selection can result in either increased or decreased reproductive divergence depending on the ecological context.

  11. The Role of Adaptive Supplemental Visual Cuing in Flight Simulation.

    DTIC Science & Technology

    1987-01-01

    aircrif!t S-1 a3o em J) e by in .re vi Aer" "yne foris eoo -., Doto f the a .ro raf t before learnin of 1!; 3p~ 1 1 e t a 3K, part ic,:larly perceptual...77-A195 932 THE ROLE OF ADAPTIVE SUPPLEMENTAL VISUAL CUING IN t/1 FLIGHT 5IMULRTION(U) AIR FORCE INST OF TECH WRIGHT-PATTERSONAFA OH E RBBILLMAN 1987...UNCLASSIFIED AF T/CI/NR-8 -iB6T F/G 5/9 UL E ,7hEcE7hEhhhhEEohEohhE EhhhhmmhhohhE _ _ , -,,.ah. .- ’-, - .. - ’ . ’ -~ ..V .. _ .. ,,. . . , ,,VW Y W

  12. Simulated annealing algorithm applied in adaptive near field beam shaping

    NASA Astrophysics Data System (ADS)

    Yu, Zhan; Ma, Hao-tong; Du, Shao-jun

    2010-11-01

    Laser beam shaping is required in many applications for improving the efficiency of the laser systems. In this paper, the near field beam shaping based on the combination of simulated annealing algorithm and Zernike polynomials is demonstrated. Considering phase distribution can be represented by the expansion of Zernike polynomials, the problem of searching appropriate phase distribution can be changed into a problem of optimizing a vector made up of Zernike coefficients. The feasibility of this method is validated theoretically by translating the Gaussian beam into square quasi-flattop beam in the near field. Finally, the closed control loop system constituted by phase only liquid crystal spatial light modulator and simulated annealing algorithm is used to prove the validity of the technique. The experiment results show that the system can generate laser beam with desired intensity distributions.

  13. Adaptive active vibration control to improve the fatigue life of a carbon-epoxy smart structure

    NASA Astrophysics Data System (ADS)

    Ripamonti, Francesco; Cazzulani, Gabriele; Cinquemani, Simone; Resta, Ferruccio; Torti, Alessandro

    2015-04-01

    Active vibration controls are helpful in improving fatigue life of structures through limitation of absolute displacements. However, control algorithms are usually designed without explicitly taking into account the fatigue phenomenon. In this paper, an adaptive vibration controller is proposed to increase the fatigue life of a smart structure made of composite material and actuated with piezoelectric patches. The main innovation with respect to the most common solutions is that the control laws are directly linked to a damage driving force, which is correlated to a fatigue damage model for the specific material. The control logic is different depending on the damage state of the structure. If no significant damage affects the structure, the controller decreases the crack nucleation probability by limiting the driving forces in the overall structure. On the contrary, if initiated cracks are present, their further propagation is prevented by controlling the damage driving forces in the already damaged areas. The structural diagnostics is performed through a vibration-based health monitoring technique, while periodical adaptation of the controller is adopted to consider damage-induced changes on the structure state-space model and to give emphasis to the most excited modes. The control algorithm has been numerically validated on the finite element model of a cantilever plate.

  14. Adaptation of MCORTEX to the AEGIS Simulation Environment.

    DTIC Science & Technology

    1984-06-01

    UNIT NUMBERS Naval Postgraduate School Monterey, GA 9 3943 I1. CONTROLLING OFFICE NAME AND ADDRESS Q2 REPORT DATE Naval Postgraduate School June 1984...general in nature . i. purs uit of these goals, MCOiTFX is confi.?ured to execute in conjunction with a commercially available operating system...real-time functions of the AEGIS weapons system and incorporation of valid simulation procesos for test and evaluation of the total system. The INTFL

  15. Introducing Molecular Life Science Students to Model Building Using Computer Simulations

    ERIC Educational Resources Information Center

    Aegerter-Wilmsen, Tinri; Kettenis, Dik; Sessink, Olivier; Hartog, Rob; Bisseling, Ton; Janssen, Fred

    2006-01-01

    Computer simulations can facilitate the building of models of natural phenomena in research, such as in the molecular life sciences. In order to introduce molecular life science students to the use of computer simulations for model building, a digital case was developed in which students build a model of a pattern formation process in…

  16. Testing Set-Point Theory in a Swiss National Sample: Reaction and Adaptation to Major Life Events

    PubMed Central

    Anusic, Ivana; Yap, Stevie C. Y.; Lucas, Richard E.

    2014-01-01

    Set-point theory posits that individuals react to the experience of major life events, but quickly adapt back to pre-event baseline levels of subjective well-being in the years following the event. A large, nationally representative panel study of Swiss households was used to examine set-point theory by investigating the extent of adaptation following the experience of marriage, childbirth, widowhood, unemployment, and disability. Our results demonstrate that major life events are associated with marked change in life satisfaction and, for some events (e.g., marriage, disability), these changes are relatively long lasting even when accounting for normative, age related change. PMID:25419036

  17. Whole genome sequencing of turbot (Scophthalmus maximus; Pleuronectiformes): a fish adapted to demersal life

    PubMed Central

    Figueras, Antonio; Robledo, Diego; Corvelo, André; Hermida, Miguel; Pereiro, Patricia; Rubiolo, Juan A.; Gómez-Garrido, Jèssica; Carreté, Laia; Bello, Xabier; Gut, Marta; Gut, Ivo Glynne; Marcet-Houben, Marina; Forn-Cuní, Gabriel; Galán, Beatriz; García, José Luis; Abal-Fabeiro, José Luis; Pardo, Belen G.; Taboada, Xoana; Fernández, Carlos; Vlasova, Anna; Hermoso-Pulido, Antonio; Guigó, Roderic; Álvarez-Dios, José Antonio; Gómez-Tato, Antonio; Viñas, Ana; Maside, Xulio; Gabaldón, Toni; Novoa, Beatriz; Bouza, Carmen; Alioto, Tyler; Martínez, Paulino

    2016-01-01

    The turbot is a flatfish (Pleuronectiformes) with increasing commercial value, which has prompted active genomic research aimed at more efficient selection. Here we present the sequence and annotation of the turbot genome, which represents a milestone for both boosting breeding programmes and ascertaining the origin and diversification of flatfish. We compare the turbot genome with model fish genomes to investigate teleost chromosome evolution. We observe a conserved macrosyntenic pattern within Percomorpha and identify large syntenic blocks within the turbot genome related to the teleost genome duplication. We identify gene family expansions and positive selection of genes associated with vision and metabolism of membrane lipids, which suggests adaptation to demersal lifestyle and to cold temperatures, respectively. Our data indicate a quick evolution and diversification of flatfish to adapt to benthic life and provide clues for understanding their controversial origin. Moreover, we investigate the genomic architecture of growth, sex determination and disease resistance, key traits for understanding local adaptation and boosting turbot production, by mapping candidate genes and previously reported quantitative trait loci. The genomic architecture of these productive traits has allowed the identification of candidate genes and enriched pathways that may represent useful information for future marker-assisted selection in turbot. PMID:26951068

  18. Whole genome sequencing of turbot (Scophthalmus maximus; Pleuronectiformes): a fish adapted to demersal life.

    PubMed

    Figueras, Antonio; Robledo, Diego; Corvelo, André; Hermida, Miguel; Pereiro, Patricia; Rubiolo, Juan A; Gómez-Garrido, Jèssica; Carreté, Laia; Bello, Xabier; Gut, Marta; Gut, Ivo Glynne; Marcet-Houben, Marina; Forn-Cuní, Gabriel; Galán, Beatriz; García, José Luis; Abal-Fabeiro, José Luis; Pardo, Belen G; Taboada, Xoana; Fernández, Carlos; Vlasova, Anna; Hermoso-Pulido, Antonio; Guigó, Roderic; Álvarez-Dios, José Antonio; Gómez-Tato, Antonio; Viñas, Ana; Maside, Xulio; Gabaldón, Toni; Novoa, Beatriz; Bouza, Carmen; Alioto, Tyler; Martínez, Paulino

    2016-06-01

    The turbot is a flatfish (Pleuronectiformes) with increasing commercial value, which has prompted active genomic research aimed at more efficient selection. Here we present the sequence and annotation of the turbot genome, which represents a milestone for both boosting breeding programmes and ascertaining the origin and diversification of flatfish. We compare the turbot genome with model fish genomes to investigate teleost chromosome evolution. We observe a conserved macrosyntenic pattern within Percomorpha and identify large syntenic blocks within the turbot genome related to the teleost genome duplication. We identify gene family expansions and positive selection of genes associated with vision and metabolism of membrane lipids, which suggests adaptation to demersal lifestyle and to cold temperatures, respectively. Our data indicate a quick evolution and diversification of flatfish to adapt to benthic life and provide clues for understanding their controversial origin. Moreover, we investigate the genomic architecture of growth, sex determination and disease resistance, key traits for understanding local adaptation and boosting turbot production, by mapping candidate genes and previously reported quantitative trait loci. The genomic architecture of these productive traits has allowed the identification of candidate genes and enriched pathways that may represent useful information for future marker-assisted selection in turbot.

  19. Output-based mesh adaptation for high order Navier-Stokes simulations on deformable domains

    NASA Astrophysics Data System (ADS)

    Kast, Steven M.; Fidkowski, Krzysztof J.

    2013-11-01

    We present an output-based mesh adaptation strategy for Navier-Stokes simulations on deforming domains. The equations are solved with an arbitrary Lagrangian-Eulerian (ALE) approach, using a discontinuous Galerkin finite-element discretization in both space and time. Discrete unsteady adjoint solutions, derived for both the state and the geometric conservation law, provide output error estimates and drive adaptation of the space-time mesh. Spatial adaptation consists of dynamic order increment or decrement on a fixed tessellation of the domain, while a combination of coarsening and refinement is used to provide an efficient time step distribution. Results from compressible Navier-Stokes simulations in both two and three dimensions demonstrate the accuracy and efficiency of the proposed approach. In particular, the method is shown to outperform other common adaptation strategies, which, while sometimes adequate for static problems, struggle in the presence of mesh motion.

  20. The numerical simulation tool for the MAORY multiconjugate adaptive optics system

    NASA Astrophysics Data System (ADS)

    Arcidiacono, C.; Schreiber, L.; Bregoli, G.; Diolaiti, E.; Foppiani, I.; Agapito, G.; Puglisi, A.; Xompero, M.; Oberti, S.; Cosentino, G.; Lombini, M.; Butler, R. C.; Ciliegi, P.; Cortecchia, F.; Patti, M.; Esposito, S.; Feautrier, P.

    2016-07-01

    The Multiconjugate Adaptive Optics RelaY (MAORY) is and Adaptive Optics module to be mounted on the ESO European-Extremely Large Telescope (E-ELT). It is an hybrid Natural and Laser Guide System that will perform the correction of the atmospheric turbulence volume above the telescope feeding the Multi-AO Imaging Camera for Deep Observations Near Infrared spectro-imager (MICADO). We developed an end-to-end Monte- Carlo adaptive optics simulation tool to investigate the performance of a the MAORY and the calibration, acquisition, operation strategies. MAORY will implement Multiconjugate Adaptive Optics combining Laser Guide Stars (LGS) and Natural Guide Stars (NGS) measurements. The simulation tool implement the various aspect of the MAORY in an end to end fashion. The code has been developed using IDL and use libraries in C++ and CUDA for efficiency improvements. Here we recall the code architecture, we describe the modeled instrument components and the control strategies implemented in the code.

  1. Communication: Spin-free quantum computational simulations and symmetry adapted states

    NASA Astrophysics Data System (ADS)

    Whitfield, James Daniel

    2013-07-01

    The ideas of digital simulation of quantum systems using a quantum computer parallel the original ideas of numerical simulation using a classical computer. In order for quantum computational simulations to advance to a competitive point, many techniques from classical simulations must be imported into the quantum domain. In this article, we consider the applications of symmetry in the context of quantum simulation. Building upon well established machinery, we propose a form of first quantized simulation that only requires the spatial part of the wave function, thereby allowing spin-free quantum computational simulations. We go further and discuss the preparation of N-body states with specified symmetries based on projection techniques. We consider two simple examples, molecular hydrogen and cyclopropenyl cation, to illustrate the ideas. The methods here are the first to explicitly deal with preparing N-body symmetry-adapted states and open the door for future investigations into group theory, chemistry, and quantum simulation.

  2. Battery Calendar Life Estimator Manual Modeling and Simulation

    SciTech Connect

    Jon P. Christophersen; Ira Bloom; Ed Thomas; Vince Battaglia

    2012-10-01

    The Battery Life Estimator (BLE) Manual has been prepared to assist developers in their efforts to estimate the calendar life of advanced batteries for automotive applications. Testing requirements and procedures are defined by the various manuals previously published under the United States Advanced Battery Consortium (USABC). The purpose of this manual is to describe and standardize a method for estimating calendar life based on statistical models and degradation data acquired from typical USABC battery testing.

  3. Battery Life Estimator Manual Linear Modeling and Simulation

    SciTech Connect

    Jon P. Christophersen; Ira Bloom; Ed Thomas; Vince Battaglia

    2009-08-01

    The Battery Life Estimator (BLE) Manual has been prepared to assist developers in their efforts to estimate the calendar life of advanced batteries for automotive applications. Testing requirements and procedures are defined by the various manuals previously published under the United States Advanced Battery Consortium (USABC). The purpose of this manual is to describe and standardize a method for estimating calendar life based on statistical models and degradation data acquired from typical USABC battery testing.

  4. Spectral-element adaptive refinement magnetohydrodynamic simulations of the island coalescence instability

    NASA Astrophysics Data System (ADS)

    Rosenberg, D.; Pouquet, A.; Germaschewski, K.; Ng, C. S.; Bhattacharjee, A.

    2006-10-01

    A recently developed spectral-element adaptive refinement incompressible magnetohydrodynamic (MHD) code is applied to simulate the problem of island coalescence instability (ICI) in 2D. The MHD solver is explicit, and uses the Elsasser formulation on high-order elements. It automatically takes advantage of the adaptive grid mechanics that have been described in [Rosenberg, Fournier, Fischer, Pouquet, J. Comp. Phys., 215, 59-80 (2006)], allowing both statically refined and dynamically refined grids. ICI is a MHD process that can produce strong current sheets and subsequent reconnection and heating in a high-Lundquist number plasma such as the solar corona [cf., Ng and Bhattacharjee, Phys. Plasmas, 5, 4028 (1998)]. Thus, it is desirable to use adaptive refinement grids to increase resolution, and to maintain accuracy at the same time. Results are compared with simulations using finite difference method with the same refinement grid, as well as pesudo-spectral simulations using uniform grid.

  5. Adaptive entropy-constrained discontinuous Galerkin method for simulation of turbulent flows

    NASA Astrophysics Data System (ADS)

    Lv, Yu; Ihme, Matthias

    2015-11-01

    A robust and adaptive computational framework will be presented for high-fidelity simulations of turbulent flows based on the discontinuous Galerkin (DG) scheme. For this, an entropy-residual based adaptation indicator is proposed to enable adaptation in polynomial and physical space. The performance and generality of this entropy-residual indicator is evaluated through direct comparisons with classical indicators. In addition, a dynamic load balancing procedure is developed to improve computational efficiency. The adaptive framework is tested by considering a series of turbulent test cases, which include homogeneous isotropic turbulence, channel flow and flow-over-a-cylinder. The accuracy, performance and scalability are assessed, and the benefit of this adaptive high-order method is discussed. The funding from NSF CAREER award is greatly acknowledged.

  6. Adaptive Control for Improved Transparency in Haptic Simulations.

    PubMed

    Abdossalami, A; Sirouspour, S

    2009-01-01

    Two adaptive nonlinear controllers are proposed for the coupling of haptic devices with impedance-type and admittance-type virtual environments, respectively. Rigid contacts in admittance-type environments are modeled either as a stiff spring or a constraint on the haptic device motion. Both controllers employ user position and force measurements to replace the natural dynamics of the haptic interface with that of an adjustable mass-damper tool. The transparency and stability of the resulting systems are investigated using a Lyapunov analysis and by taking into account uncertain nonlinear dynamics for the haptic device, and uncertain mass-spring-damper type dynamics for the user and virtual environment. It is shown analytically that low-pass filtering of selected terms in the control signal can significantly reduce a stability related lower bound on the achievable synthesized mass of the haptic interface in a discrete-time implementation of the controllers. An optimization problem is formulated and solved to balance impedance reduction against noise amplification in choosing the filter gain and bandwidth. The proposed controllers as well as a conventional penalty-based method are compared in a set of experiments. The results indicate that the controller with an admittance-type constraint-based rigid environment has far superior performance in terms of the range of impedances that it can stably display to the user.

  7. Role-play simulations for climate change adaptation education and engagement

    NASA Astrophysics Data System (ADS)

    Rumore, Danya; Schenk, Todd; Susskind, Lawrence

    2016-08-01

    In order to effectively adapt to climate change, public officials and other stakeholders need to rapidly enhance their understanding of local risks and their ability to collaboratively and adaptively respond to them. We argue that science-based role-play simulation exercises -- a type of 'serious game' involving face-to-face mock decision-making -- have considerable potential as education and engagement tools for enhancing readiness to adapt. Prior research suggests role-play simulations and other serious games can foster public learning and encourage collective action in public policy-making contexts. However, the effectiveness of such exercises in the context of climate change adaptation education and engagement has heretofore been underexplored. We share results from two research projects that demonstrate the effectiveness of role-play simulations in cultivating climate change adaptation literacy, enhancing collaborative capacity and facilitating social learning. Based on our findings, we suggest such exercises should be more widely embraced as part of adaptation professionals' education and engagement toolkits.

  8. Numerical Simulation of turbulent flow and sediment transport around real-life stream restoration structures

    NASA Astrophysics Data System (ADS)

    Khosronejad, Ali; Sotiropoulos, Fotis

    2011-11-01

    Local scour around three real-life in-stream restoration rock structures, including a rock-vane, a cross-vane, and a J-hook, is investigated numerically. To overcome the difficulties of generating high quality boundary-fitted meshes in natural mobile-bed channels with embedded rock structures, we employ the fluid-structure interaction Curvilinear Immersed Boundary (CURVIB) method adapted for morphodynamic simulations (Khosronejad et al., Adv. Water Res., 34(7) 2011). The mobile bed and the immersed structures are discretized with an unstructured triangular mesh and are treated as sharp-interface immersed boundaries embedded in a background curvilinear mesh used to discretize the fluid domain. The flow field is simulated by solving the unsteady RANS equations closed with the k-w turbulence model. The bed evolution is calculated by solving the Exner equation using an unstructured, finite-volume formulation. Comparisons with measurements show that the computed results capture both the spatial and temporal features of scour and deposition patterns with good accuracy. This work was supported by NSF Grants EAR-0120914 and EAR-0738726, National Cooperative Highway Research Program Grant NCHRP-HR 24-33, and a Grant from Yonsei University.

  9. Australian nursing students' stories of end-of-life care simulation.

    PubMed

    Gillan, Pauline Catherine; van der Riet, Pamela; Jeong, Sarah

    2016-03-01

    Because nurses are at the forefront of end-of-life care, it is imperative that nursing students are prepared for this role upon graduation. Research suggests that many nursing students are unprepared to deliver compassionate and quality end-of-life care. There have been many attempts to address this need; one emerging method is end-of-life care simulation. This paper explores the experiences of 18 undergraduate nursing students of end-of-life care simulation. Participants' stories were obtained via observation during end-of-life care simulation, audio-recorded post simulation debriefing, and semi-structured interviews. Using Clandinin and Connolly's three dimensions of Narrative Inquiry (temporality, spatiality, and sociality) participants' stories reflected convergence of time, place, and person. Findings revealed three distinct plotlines along a time continuum, specifically surrounding time of death: (i) "The privilege of end-of-life care;" (ii) "Witnessing death as surreal;" and (iii) "The honor of providing after-death care." Participants' narratives suggest that end-of-life care simulation is an important means of preparing students for clinical end-of-life care experiences. This has implications for nursing educators wishing to consider simulation in end-of-life care education.

  10. Optimal Control Problem of Feeding Adaptations of Daphnia and Neural Network Simulation

    NASA Astrophysics Data System (ADS)

    Kmet', Tibor; Kmet'ov, Mria

    2010-09-01

    A neural network based optimal control synthesis is presented for solving optimal control problems with control and state constraints and open final time. The optimal control problem is transcribed into nonlinear programming problem, which is implemented with adaptive critic neural network [9] and recurrent neural network for solving nonlinear proprojection equations [10]. The proposed simulation methods is illustrated by the optimal control problem of feeding adaptation of filter feeders of Daphnia. Results show that adaptive critic based systematic approach and neural network solving of nonlinear equations hold promise for obtaining the optimal control with control and state constraints and open final time.

  11. Life-history consequences of adaptation to pollution. "Daphnia longispina clones historically exposed to copper".

    PubMed

    Agra, Ana Raquel; Soares, Amadeu M V M; Barata, Carlos

    2011-05-01

    The present study was conducted to assess life history effects of adaptation to pollution in Daphnia longispina clones historically exposed to an acid mine drainage from an abandoned pyrite mine. Four sensitive and resistant clones from reference and impacted populations were exposed to a range of copper exposure levels and their life history and physiological responses in terms of survival, reproduction, respiration and feeding rates compared. The most resistant clone was from 16 to 48 fold more tolerant to copper in terms of LC(50) and population growth rates than sensitive ones, respectively. The genetic differences between the resistant and sensitive clones were that in the polluted environment individuals of the resistant clone survived 50% better, reproduced 3 days earlier, grew 20% better, produced three more offspring per day and had population growth rates 45% greater. In the unpolluted environment, however, individuals from the resistant clone had the lowest reproduction and somatic growth rates but equivalent population growth rates, than sensitive daphnids. Thus, these life history changes did not translate into lower fitness in unpolluted environments in terms of population growth rates. Observed higher respiration rates of the most resistant clone support in part the energy cost hypothesis of tolerance, whereas increase feeding, reproduction and growth rates across copper exposure levels may also, indicate that resistant individuals need copper to fulfil they physiological demands thus supporting the metal deficiency hypothesis as well.

  12. Computational efficiency and Amdahl’s law for the adaptive resolution simulation technique

    DOE PAGES

    Junghans, Christoph; Agarwal, Animesh; Delle Site, Luigi

    2017-06-01

    Here, we discuss the computational performance of the adaptive resolution technique in molecular simulation when it is compared with equivalent full coarse-grained and full atomistic simulations. We show that an estimate of its efficiency, within 10%–15% accuracy, is given by the Amdahl’s Law adapted to the specific quantities involved in the problem. The derivation of the predictive formula is general enough that it may be applied to the general case of molecular dynamics approaches where a reduction of degrees of freedom in a multi scale fashion occurs.

  13. Crops and climate change: progress, trends, and challenges in simulating impacts and informing adaptation.

    PubMed

    Challinor, Andrew J; Ewert, Frank; Arnold, Steve; Simelton, Elisabeth; Fraser, Evan

    2009-01-01

    Assessments of the relationships between crop productivity and climate change rely upon a combination of modelling and measurement. As part of this review, this relationship is discussed in the context of crop and climate simulation. Methods for linking these two types of models are reviewed, with a primary focus on large-area crop modelling techniques. Recent progress in simulating the impacts of climate change on crops is presented, and the application of these methods to the exploration of adaptation options is discussed. Specific advances include ensemble simulations and improved understanding of biophysical processes. Finally, the challenges associated with impacts and adaptation research are discussed. It is argued that the generation of knowledge for policy and adaptation should be based not only on syntheses of published studies, but also on a more synergistic and holistic research framework that includes: (i) reliable quantification of uncertainty; (ii) techniques for combining diverse modelling approaches and observations that focus on fundamental processes; and (iii) judicious choice and calibration of models, including simulation at appropriate levels of complexity that accounts for the principal drivers of crop productivity, which may well include both biophysical and socio-economic factors. It is argued that such a framework will lead to reliable methods for linking simulation to real-world adaptation options, thus making practical use of the huge global effort to understand and predict climate change.

  14. Can multi-generational exposure to ocean warming and acidification lead to the adaptation of life history and physiology in a marine metazoan?

    PubMed

    Gibbin, Emma M; Chakravarti, Leela J; Jarrold, Michael D; Christen, Felix; Turpin, Vincent; Massamba N'Siala, Gloria; Blier, Pierre U; Calosi, Piero

    2017-02-15

    Ocean warming and acidification are concomitant global drivers that are currently threatening the survival of marine organisms. How species will respond to these changes depends on their capacity for plastic and adaptive responses. Little is known about the mechanisms that govern plasticity and adaptability or how global changes will influence these relationships across multiple generations. Here, we exposed the emerging model marine polychaete Ophryotrocha labronica to conditions simulating ocean warming and acidification, in isolation and in combination over five generations to identify: (i) how multiple versus single global change drivers alter both juvenile and adult life-history traits; (ii) the mechanistic link between adult physiological and fitness-related life-history traits; and (iii) whether the phenotypic changes observed over multiple generations are of plastic and/or adaptive origin. Two juvenile (developmental rate; survival to sexual maturity) and two adult (average reproductive body size; fecundity) life-history traits were measured in each generation, in addition to three physiological (cellular reactive oxygen species content, mitochondrial density, mitochondrial capacity) traits. We found that multi-generational exposure to warming alone caused an increase in juvenile developmental rate, reactive oxygen species production and mitochondrial density, decreases in average reproductive body size and fecundity, and fluctuations in mitochondrial capacity, relative to control conditions. Exposure to ocean acidification alone had only minor effects on juvenile developmental rate. Remarkably, when both drivers of global change were present, only mitochondrial capacity was significantly affected, suggesting that ocean warming and acidification act as opposing vectors of stress across multiple generations.

  15. Sex-specific local life-history adaptation in surface- and cave-dwelling Atlantic mollies (Poecilia mexicana)

    PubMed Central

    Riesch, Rüdiger; Reznick, David N.; Plath, Martin; Schlupp, Ingo

    2016-01-01

    Cavefishes have long been used as model organisms showcasing adaptive diversification, but does adaptation to caves also facilitate the evolution of reproductive isolation from surface ancestors? We raised offspring of wild-caught surface- and cave-dwelling ecotypes of the neotropical fish Poecilia mexicana to sexual maturity in a 12-month common garden experiment. Fish were raised under one of two food regimes (high vs. low), and this was crossed with differences in lighting conditions (permanent darkness vs. 12:12 h light:dark cycle) in a 2 × 2 factorial design, allowing us to elucidate potential patterns of local adaptation in life histories. Our results reveal a pattern of sex-specific local life-history adaptation: Surface molly females had the highest fitness in the treatment best resembling their habitat of origin (high food and a light:dark cycle), and suffered from almost complete reproductive failure in darkness, while cave molly females were not similarly affected in any treatment. Males of both ecotypes, on the other hand, showed only weak evidence for local adaptation. Nonetheless, local life-history adaptation in females likely contributes to ecological diversification in this system and other cave animals, further supporting the role of local adaptation due to strong divergent selection as a major force in ecological speciation. PMID:26960566

  16. Sex-specific local life-history adaptation in surface- and cave-dwelling Atlantic mollies (Poecilia mexicana).

    PubMed

    Riesch, Rüdiger; Reznick, David N; Plath, Martin; Schlupp, Ingo

    2016-03-10

    Cavefishes have long been used as model organisms showcasing adaptive diversification, but does adaptation to caves also facilitate the evolution of reproductive isolation from surface ancestors? We raised offspring of wild-caught surface- and cave-dwelling ecotypes of the neotropical fish Poecilia mexicana to sexual maturity in a 12-month common garden experiment. Fish were raised under one of two food regimes (high vs. low), and this was crossed with differences in lighting conditions (permanent darkness vs. 12:12 h light:dark cycle) in a 2 × 2 factorial design, allowing us to elucidate potential patterns of local adaptation in life histories. Our results reveal a pattern of sex-specific local life-history adaptation: Surface molly females had the highest fitness in the treatment best resembling their habitat of origin (high food and a light:dark cycle), and suffered from almost complete reproductive failure in darkness, while cave molly females were not similarly affected in any treatment. Males of both ecotypes, on the other hand, showed only weak evidence for local adaptation. Nonetheless, local life-history adaptation in females likely contributes to ecological diversification in this system and other cave animals, further supporting the role of local adaptation due to strong divergent selection as a major force in ecological speciation.

  17. Resolution-Adapted All-Atomic and Coarse-Grained Model for Biomolecular Simulations.

    PubMed

    Shen, Lin; Hu, Hao

    2014-06-10

    We develop here an adaptive multiresolution method for the simulation of complex heterogeneous systems such as the protein molecules. The target molecular system is described with the atomistic structure while maintaining concurrently a mapping to the coarse-grained models. The theoretical model, or force field, used to describe the interactions between two sites is automatically adjusted in the simulation processes according to the interaction distance/strength. Therefore, all-atomic, coarse-grained, or mixed all-atomic and coarse-grained models would be used together to describe the interactions between a group of atoms and its surroundings. Because the choice of theory is made on the force field level while the sampling is always carried out in the atomic space, the new adaptive method preserves naturally the atomic structure and thermodynamic properties of the entire system throughout the simulation processes. The new method will be very useful in many biomolecular simulations where atomistic details are critically needed.

  18. A widespread chromosomal inversion polymorphism contributes to a major life-history transition, local adaptation, and reproductive isolation.

    PubMed

    Lowry, David B; Willis, John H

    2010-09-28

    The role of chromosomal inversions in adaptation and speciation is controversial. Historically, inversions were thought to contribute to these processes either by directly causing hybrid sterility or by facilitating the maintenance of co-adapted gene complexes. Because inversions suppress recombination when heterozygous, a recently proposed local adaptation mechanism predicts that they will spread if they capture alleles at multiple loci involved in divergent adaptation to contrasting environments. Many empirical studies have found inversion polymorphisms linked to putatively adaptive phenotypes or distributed along environmental clines. However, direct involvement of an inversion in local adaptation and consequent ecological reproductive isolation has not to our knowledge been demonstrated in nature. In this study, we discovered that a chromosomal inversion polymorphism is geographically widespread, and we test the extent to which it contributes to adaptation and reproductive isolation under natural field conditions. Replicated crosses between the prezygotically reproductively isolated annual and perennial ecotypes of the yellow monkeyflower, Mimulus guttatus, revealed that alternative chromosomal inversion arrangements are associated with life-history divergence over thousands of kilometers across North America. The inversion polymorphism affected adaptive flowering time divergence and other morphological traits in all replicated crosses between four pairs of annual and perennial populations. To determine if the inversion contributes to adaptation and reproductive isolation in natural populations, we conducted a novel reciprocal transplant experiment involving outbred lines, where alternative arrangements of the inversion were reciprocally introgressed into the genetic backgrounds of each ecotype. Our results demonstrate for the first time in nature the contribution of an inversion to adaptation, an annual/perennial life-history shift, and multiple reproductive

  19. Gaps in Social Support Resources in Later Life: An Adaptational Challenge in Need of Further Research.

    PubMed

    Rook, Karen S

    2009-02-01

    Gaps in social support resources in later life may arise when older adults lose social network members due to illness, death, or residential relocation. Gaps also may arise when social networks remain intact but are not well suited to meet older adults' intensifying support needs, such as needs for extended or highly personal instrumental support. Significant gaps in support resources are likely to require adaptive responses by older adults. This discussion highlights theoretical perspectives and illustrates empirical findings regarding the nature and effectiveness of older adults' responses to gaps in their social support resources. The literature examining these issues is relatively small and, as a result, is ripe for further development. Promising directions for future research are suggested.

  20. Adaptability test of lettuce to soil-like substrate in bioregenerative life support system

    NASA Astrophysics Data System (ADS)

    Min, Yan; Liu, Professor Hong; Wenting, Fu

    Plant cultivation using soil-like substrate (SLS) is considered to be a feasible option for building up matter for biological turnover in bioregenerative life support system (BLSS) by many researchers. The characteristics of SLS are different from those of true soil therefore it is very important to study the adaptability of candidate crop to SLS in BLSS. This study was carried out in three successive steps to test the adaptability of lettuce (Lactuca sativa L.) to rice straw SLS in BLSS of China. First, six Chinese specific lettuce cultivars which were selected for Chinese advanced life support system were planted into the same rice straw SLS, which was to determine the more suitable plant cultivar to do the next experiment. The results showed that Sharp Leaf lettuce and Red lettuce were more suitable for SLS than other cultivars. Second, the possibility of increasing the crop yield on the SLS was conducted by changing the soil depth and plant density. Sharp Leaf lettuce and Red lettuce were used into this experiment in order to obtain the highest yield under the smallest soil volume and weight at the same light intensity. Crop edible biomass, crop nutrition content and photosynthetic characteristics were estimated during the experiment. Red lettuce obtained higher biomass and photosynthesis capacity. Lastly, the stability of planting system of lettuce and SLS was evaluated in the closed controlled system. Red lettuce would be the test plant. In this experiment different age lettuce groups would be planted together and gas exchange would be measured. In all of these experiments soil physical and chemical characteristics were also be measured which will be the basal data for further research.

  1. Greek adaptation and validation of the Ankylosing Spondylitis Quality of Life (ASQoL) measure

    PubMed Central

    Graham, J E; Rouse, M; Twiss, J; McKenna, S P; Vidalis, A A

    2015-01-01

    Background Ankylosing Spondylitis (AS) is a chronic rheumatic disease that has a significant impact on patient’s quality of life (QoL). The Ankylosing Spondylitis Quality of Life (ASQoL) questionnaire is a disease-specific patient-reported outcome measure for assessing QoL in AS. While the ASQoL has been adapted for use in 46 countries worldwide, a Greek language version of the measure has not been available and was required for an international clinical trial. Aim The aim was to develop and assess the psychometric properties of a Greek language version of the ASQoL. Methods The adaptation of the ASQoL into Greek involved three procedures: translation, assessment of face and content validity, and formal validation. The measure was translated into Greek using two translation panels. Cognitive debriefing interviews were employed to determine face and content validity. Finally, the translation’s psychometric properties were examined by administering it on two occasions, with a 14-day interval. The Nottingham Health Profile (NHP) was used as a comparator measure. Results The ASQoL proved straightforward to translate into Greek and interviewees found it relevant, comprehensible and easy to complete.  The measure had good internal consistency (α =0.92) and test-retest reliability (r =0.98). Predicted correlations with the NHP provided evidence of the convergent validity of the two measures. Construct validity was confirmed by the measure’s ability to distinguish groups of AS patients varying by perceived disease severity and general health. Conclusions The Greek ASQoL has been shown to be well-accepted, reliable and valid and can be recommended for use in clinical studies and routine clinical practice in AS. Hippokratia 2015; 19 (2):119-124. PMID:27418759

  2. Adaptability of small brown planthopper to four rice cultivars using life table and population projection method

    PubMed Central

    Zheng, Xiao-Min; Tao, Yun-Li; Chi, Hsin; Wan, Fang-Hao; Chu, Dong

    2017-01-01

    In this study, we evaluated the adaptability of the small brown planthopper (SBPH), Laodelphax striatellus (Hemiptera: Delphacidae) to four rice cultivars including Shengdao13 (SD13), Shengdao14 (SD14), Shengdao15 (SD15), and Zixiangnuo (ZXN) using the age-stage, two-sex life table with a simplified method for recording egg production (i.e., every five days vs. daily). The intrinsic rate of increase (r) of the SBPH was the highest (0.1067 d−1) on cultivar SD15, which was similar to the rate on SD14 (0.1029 d−1), but was significantly higher than that occurring on ZXN (0.0897 d−1) and SD13 (0.0802 d−1). The differences of the finite rate of increase (λ) on the four rice cultivars were consistent with the r values. Population projection predicted an explosive population growth of the SBPH occurring in a relatively short time when reared on SD14 and SD15. These findings demonstrated that the SBPH can successfully survive on the four rice cultivars, although there were varying host adaptabilities. PMID:28205522

  3. An Adaptation To Life In Acid Through A Novel Mevalonate Pathway

    PubMed Central

    Vinokur, Jeffrey M.; Cummins, Matthew C.; Korman, Tyler P.; Bowie, James U.

    2016-01-01

    Extreme acidophiles are capable of growth at pH values near zero. Sustaining life in acidic environments requires extensive adaptations of membranes, proton pumps, and DNA repair mechanisms. Here we describe an adaptation of a core biochemical pathway, the mevalonate pathway, in extreme acidophiles. Two previously known mevalonate pathways involve ATP dependent decarboxylation of either mevalonate 5-phosphate or mevalonate 5-pyrophosphate, in which a single enzyme carries out two essential steps: (1) phosphorylation of the mevalonate moiety at the 3-OH position and (2) subsequent decarboxylation. We now demonstrate that in extreme acidophiles, decarboxylation is carried out by two separate steps: previously identified enzymes generate mevalonate 3,5-bisphosphate and a new decarboxylase we describe here, mevalonate 3,5-bisphosphate decarboxylase, produces isopentenyl phosphate. Why use two enzymes in acidophiles when one enzyme provides both functionalities in all other organisms examined to date? We find that at low pH, the dual function enzyme, mevalonate 5-phosphate decarboxylase is unable to carry out the first phosphorylation step, yet retains its ability to perform decarboxylation. We therefore propose that extreme acidophiles had to replace the dual-purpose enzyme with two specialized enzymes to efficiently produce isoprenoids in extremely acidic environments. PMID:28004831

  4. Adaptive optics vision simulation and perceptual learning system based on a 35-element bimorph deformable mirror.

    PubMed

    Dai, Yun; Zhao, Lina; Xiao, Fei; Zhao, Haoxin; Bao, Hua; Zhou, Hong; Zhou, Yifeng; Zhang, Yudong

    2015-02-10

    An adaptive optics visual simulation combined with a perceptual learning (PL) system based on a 35-element bimorph deformable mirror (DM) was established. The larger stroke and smaller size of the bimorph DM made the system have larger aberration correction or superposition ability and be more compact. By simply modifying the control matrix or the reference matrix, select correction or superposition of aberrations was realized in real time similar to a conventional adaptive optics closed-loop correction. PL function was first integrated in addition to conventional adaptive optics visual simulation. PL training undertaken with high-order aberrations correction obviously improved the visual function of adult anisometropic amblyopia. The preliminary application of high-order aberrations correction with PL training on amblyopia treatment was being validated with a large scale population, which might have great potential in amblyopia treatment and visual performance maintenance.

  5. Towards adaptive kinetic-fluid simulations of low-temperature plasmas

    NASA Astrophysics Data System (ADS)

    Kolobov, Vladimir

    2013-09-01

    The emergence of new types of gaseous electronics in multi-phase systems calls for computational tools with adaptive kinetic-fluid simulation capabilities. We will present an Adaptive Mesh and Algorithm Refinement (AMAR) methodology for multi-scale simulations of gas flows and discuss current efforts towards extending this methodology for weakly ionized plasmas. The AMAR method combines Adaptive Mesh Refinement (AMR) with automatic selection of kinetic or fluid solvers in different parts of computational domains. This AMAR methodology was implemented in our Unified Flow Solver (UFS) for mixed rarefied and continuum flows. UFS uses discrete velocity method for solving Boltzmann kinetic equation under rarefied flow conditions coupled to fluid (Navier-Stokes) solvers for continuum flow regimes. The main challenge of extending AMAR to plasmas comes from the distinction of electron and atom mass. We will present multi-fluid, two-temperature plasma models with AMR capabilities for simulations of glow, corona, and streamer discharges. We will briefly discuss specifics of electron kinetics in collisional plasmas, and deterministic methods of solving kinetic equations for different electron groups. Kinetic solvers with Adaptive Mesh in Phase Space (AMPS) will be introduced to solve Boltzmann equation for electrons in the presence of electric fields, elastic and inelastic collisions with atoms. These kinetic and fluid models are currently being incorporated into AMAR methodology for multi-scale simulations of low-temperature plasmas in multi-phase systems. Supported by AFOSR, NASA, and DoE

  6. An Interactive Computer Program to Construct Adaptive Landscapes and to Simulate the Changes Expected with Selection

    ERIC Educational Resources Information Center

    Hull, Peter

    1978-01-01

    Describes an interactive computer program which can be used by students to construct adaptive landscapes of two types as an illustration of the expected effects of selection. Simulates effects of selection on populations of this type and changes of gene frequency can be plotted on the same contour map. (Author/MA)

  7. Simulation Based Evaluation of Integrated Adaptive Control and Flight Planning Technologies

    NASA Technical Reports Server (NTRS)

    Campbell, Stefan Forrest; Kaneshige, John T.

    2008-01-01

    The objective of this work is to leverage NASA resources to enable effective evaluation of resilient aircraft technologies through simulation. This includes examining strengths and weaknesses of adaptive controllers, emergency flight planning algorithms, and flight envelope determination algorithms both individually and as an integrated package.

  8. A Simulation Study of Methods for Assessing Differential Item Functioning in Computerized Adaptive Tests.

    ERIC Educational Resources Information Center

    Zwick, Rebecca; And Others

    1994-01-01

    Simulated data were used to investigate the performance of modified versions of the Mantel-Haenszel method of differential item functioning (DIF) analysis in computerized adaptive tests (CAT). Results indicate that CAT-based DIF procedures perform well and support the use of item response theory-based matching variables in DIF analysis. (SLD)

  9. A Simulation Study of Methods for Assessing Differential Item Functioning in Computer-Adaptive Tests.

    ERIC Educational Resources Information Center

    Zwick, Rebecca; And Others

    Simulated data were used to investigate the performance of modified versions of the Mantel-Haenszel and standardization methods of differential item functioning (DIF) analysis in computer-adaptive tests (CATs). Each "examinee" received 25 items out of a 75-item pool. A three-parameter logistic item response model was assumed, and…

  10. Firestar-"D": Computerized Adaptive Testing Simulation Program for Dichotomous Item Response Theory Models

    ERIC Educational Resources Information Center

    Choi, Seung W.; Podrabsky, Tracy; McKinney, Natalie

    2012-01-01

    Computerized adaptive testing (CAT) enables efficient and flexible measurement of latent constructs. The majority of educational and cognitive measurement constructs are based on dichotomous item response theory (IRT) models. An integral part of developing various components of a CAT system is conducting simulations using both known and empirical…

  11. Simulation of the electrically stimulated cochlear neuron: modeling adaptation to trains of electric pulses.

    PubMed

    Woo, Jihwan; Miller, Charles A; Abbas, Paul J

    2009-05-01

    The Hodgkin-Huxley (HH) model does not simulate the significant changes in auditory nerve fiber (ANF) responses to sustained stimulation that are associated with neural adaptation. Given that the electric stimuli used by cochlear prostheses can result in adapted responses, a computational model incorporating an adaptation process is warranted if such models are to remain relevant and contribute to related research efforts. In this paper, we describe the development of a modified HH single-node model that includes potassium ion ( K(+)) concentration changes in response to each action potential. This activity-related change results in an altered resting potential, and hence, excitability. Our implementation of K(+)-related changes uses a phenomenological approach based upon K(+) accumulation and dissipation time constants. Modeled spike times were computed using repeated presentations of modeled pulse-train stimuli. Spike-rate adaptation was characterized by rate decrements and time constants and compared against ANF data from animal experiments. Responses to relatively low (250 pulse/s) and high rate (5000 pulse/s) trains were evaluated and the novel adaptation model results were compared against model results obtained without the adaptation mechanism. In addition to spike-rate changes, jitter and spike intervals were evaluated and found to change with the addition of modeled adaptation. These results provide one means of incorporating a heretofore neglected (although important) aspect of ANF responses to electric stimuli. Future studies could include evaluation of alternative versions of the adaptation model elements and broadening the model to simulate a complete axon, and eventually, a spatially realistic model of the electrically stimulated nerve within extracochlear tissues.

  12. Adaptation to Life in the High Andes: Nocturnal Oxyhemoglobin Saturation in Early Development

    PubMed Central

    Hill, Catherine Mary; Baya, Ana; Gavlak, Johanna; Carroll, Annette; Heathcote, Kate; Dimitriou, Dagmara; L'Esperance, Veline; Webster, Rebecca; Holloway, John; Virues-Ortega, Javier; Kirkham, Fenella Jane; Bucks, Romola Starr; Hogan, Alexandra Marie

    2016-01-01

    observations. Citation: Hill CM, Baya A, Gavlak J, Carroll A, Heathcote K, Dimitriou D, L'Esperance V, Webster R, Holloway J, Virues-Ortega J, Kirkham FJ, Bucks RS, Hogan AM. Adaptation to life in the high andes: nocturnal oxyhemoglobin saturation in early development. SLEEP 2016;39(5):1001–1008. PMID:26951394

  13. Local error estimates for adaptive simulation of the Reaction-Diffusion Master Equation via operator splitting.

    PubMed

    Hellander, Andreas; Lawson, Michael J; Drawert, Brian; Petzold, Linda

    2014-06-01

    The efficiency of exact simulation methods for the reaction-diffusion master equation (RDME) is severely limited by the large number of diffusion events if the mesh is fine or if diffusion constants are large. Furthermore, inherent properties of exact kinetic-Monte Carlo simulation methods limit the efficiency of parallel implementations. Several approximate and hybrid methods have appeared that enable more efficient simulation of the RDME. A common feature to most of them is that they rely on splitting the system into its reaction and diffusion parts and updating them sequentially over a discrete timestep. This use of operator splitting enables more efficient simulation but it comes at the price of a temporal discretization error that depends on the size of the timestep. So far, existing methods have not attempted to estimate or control this error in a systematic manner. This makes the solvers hard to use for practitioners since they must guess an appropriate timestep. It also makes the solvers potentially less efficient than if the timesteps are adapted to control the error. Here, we derive estimates of the local error and propose a strategy to adaptively select the timestep when the RDME is simulated via a first order operator splitting. While the strategy is general and applicable to a wide range of approximate and hybrid methods, we exemplify it here by extending a previously published approximate method, the Diffusive Finite-State Projection (DFSP) method, to incorporate temporal adaptivity.

  14. Adaptive constructive processes and memory accuracy: Consequences of counterfactual simulations in young and older adults

    PubMed Central

    Gerlach, Kathy D.; Dornblaser, David W.; Schacter, Daniel L.

    2013-01-01

    People frequently engage in counterfactual thinking: mental simulations of alternative outcomes to past events. Like simulations of future events, counterfactual simulations serve adaptive functions. However, future simulation can also result in various kinds of distortions and has thus been characterized as an adaptive constructive process. Here we approach counterfactual thinking as such and examine whether it can distort memory for actual events. In Experiments 1a/b, young and older adults imagined themselves experiencing different scenarios. Participants then imagined the same scenario again, engaged in no further simulation of a scenario, or imagined a counterfactual outcome. On a subsequent recognition test, participants were more likely to make false alarms to counterfactual lures than novel scenarios. Older adults were more prone to these memory errors than younger adults. In Experiment 2, younger and older participants selected and performed different actions, then recalled performing some of those actions, imagined performing alternative actions to some of the selected actions, and did not imagine others. Participants, especially older adults, were more likely to falsely remember counterfactual actions than novel actions as previously performed. The findings suggest that counterfactual thinking can cause source confusion based on internally generated misinformation, consistent with its characterization as an adaptive constructive process. PMID:23560477

  15. A well-balanced numerical scheme for shallow water simulation on adaptive grids

    NASA Astrophysics Data System (ADS)

    Zhang, H. J.; Zhou, J. Z.; Bi, S.; Li, Q. Q.; Fan, Y.

    2014-04-01

    The efficiency of solving two-dimensional shallow-water equations (SWEs) is vital for simulation of large-scale flood inundation. For flood flows over real topography, local high-resolution method, which uses adaptable grids, is required in order to prevent the loss of accuracy of the flow pattern while saving computational cost. This paper introduces an adaptive grid model, which uses an adaptive criterion calculated on the basis of the water lever. The grid adaption is performed by manipulating subdivision levels of the computation grids. As the flow feature varies during the shallow wave propagation, the local grid density changes adaptively and the stored information of neighbor relationship updates correspondingly, achieving a balance between the model accuracy and running efficiency. In this work, a well-balanced (WB) scheme for solving SWEs is introduced. In reconstructions of Riemann state, the definition of the unique bottom elevation on grid interfaces is modified, and the numerical scheme is pre-balanced automatically. By the validation against two idealist test cases, the proposed model is applied to simulate flood inundation due to a dam-break of Zhanghe Reservoir, Hubei province, China. The results show that the presented model is robust and well-balanced, has nice computational efficiency and numerical stability, and thus has bright application prospects.

  16. Applications of weakly compressible model to turbulent flow problem towards adaptive turbulence simulation

    NASA Astrophysics Data System (ADS)

    Tsuji, Takuya; Yokomine, Takehiko; Shimizu, Akihiko

    2002-11-01

    We have been engaged in the development of multi-scale adaptive simulation technique for incompressible turbulent flow. This is designed as that important scale components in the flow field are detected automatically by lifting wavelet and solved selectively. In conventional incompressible scheme, it is very common to solve Poisson equation of pressure to meet the divergence free constraints of incompressible flow. It may be not impossible to solve the Poisson eq. in the adaptive way, but this is very troublesome because it requires generation of control volume at each time step. We gave an eye on weakly compressible model proposed by Bao(2001). This model was derived from zero Mach limit asymptotic analysis of compressible Navier-Stokes eq. and does not need to solve the Poisson eq. at all. But it is relatively new and it requires demonstration study before the combination with the adaptation by wavelet. In present study, 2-D and 3-D Backstep flow were selected as test problems and applicability to turbulent flow is verified in detail. Besides, combination of adaptation by wavelet with weakly compressible model towards the adaptive turbulence simulation is discussed.

  17. Adaptive finite element simulation of flow and transport applications on parallel computers

    NASA Astrophysics Data System (ADS)

    Kirk, Benjamin Shelton

    The subject of this work is the adaptive finite element simulation of problems arising in flow and transport applications on parallel computers. Of particular interest are new contributions to adaptive mesh refinement (AMR) in this parallel high-performance context, including novel work on data structures, treatment of constraints in a parallel setting, generality and extensibility via object-oriented programming, and the design/implementation of a flexible software framework. This technology and software capability then enables more robust, reliable treatment of multiscale--multiphysics problems and specific studies of fine scale interaction such as those in biological chemotaxis (Chapter 4) and high-speed shock physics for compressible flows (Chapter 5). The work begins by presenting an overview of key concepts and data structures employed in AMR simulations. Of particular interest is how these concepts are applied in the physics-independent software framework which is developed here and is the basis for all the numerical simulations performed in this work. This open-source software framework has been adopted by a number of researchers in the U.S. and abroad for use in a wide range of applications. The dynamic nature of adaptive simulations pose particular issues for efficient implementation on distributed-memory parallel architectures. Communication cost, computational load balance, and memory requirements must all be considered when developing adaptive software for this class of machines. Specific extensions to the adaptive data structures to enable implementation on parallel computers is therefore considered in detail. The libMesh framework for performing adaptive finite element simulations on parallel computers is developed to provide a concrete implementation of the above ideas. This physics-independent framework is applied to two distinct flow and transport applications classes in the subsequent application studies to illustrate the flexibility of the

  18. Adaptation to Phosphene Parameters Based on Multi-Object Recognition Using Simulated Prosthetic Vision.

    PubMed

    Xia, Peng; Hu, Jie; Peng, Yinghong

    2015-12-01

    Retinal prostheses for the restoration of functional vision are under development and visual prostheses targeting proximal stages of the visual pathway are also being explored. To investigate the experience with visual prostheses, psychophysical experiments using simulated prosthetic vision in normally sighted individuals are necessary. In this study, a helmet display with real-time images from a camera attached to the helmet provided the simulated vision, and experiments of recognition and discriminating multiple objects were used to evaluate visual performance under different parameters (gray scale, distortion, and dropout). The process of fitting and training with visual prostheses was simulated and estimated by adaptation to the parameters with time. The results showed that the increase in the number of gray scale and the decrease in phosphene distortion and dropout rate improved recognition performance significantly, and the recognition accuracy was 61.8 ± 7.6% under the optimum condition (gray scale: 8, distortion: k = 0, dropout: 0%). The adaption experiments indicated that the recognition performance was improved with time and the effect of adaptation to distortion was greater than dropout, which implies the difference of adaptation mechanism to the two parameters.

  19. Moment preserving adaptive particle weights using octree velocity distributions for PIC simulations

    SciTech Connect

    Martin, Robert Scott; Cambier, Jean-Luc

    2012-11-27

    The ratio of computational to physical particles is of primary concern to statistical particle based simulations such as DSMC and PIC. An adaptive computational particle weight algorithm is presented that conserves mass, momentum, and energy. This algorithm is then enhanced with an octree adaptive mesh in velocity space to mitigate artificial thermalization. The new octree merge is compared to a merge that randomly selects merge partners for a bi-Maxwellian velocity distribution. Results for crossing beams in a fixed potential well along with an electrostatic PIC version with and without MCC collisions based ionizing breakdown show the advantages of the merge algorithm to both fixed particle weights and randomly selected merge partners.

  20. Early cardiovascular adaptation to zero gravity simulated by head-down tilt

    NASA Technical Reports Server (NTRS)

    Blomqvist, C. G.; Nixon, J. V.; Johnson, R. L., Jr.; Mitchell, J. H.

    1979-01-01

    The early cardiovascular adaptation to zero gravity, simulated by head-down tilt at 5 deg, was studied in a series of 10 normal young men. The validity of the model was confirmed by comparing the results with data from Apollo and Skylab flights. Tilt produced a significant central fluid shift with a transient increase in central venous pressure, later followed by an increase in left ventricular size without changes in cardiac output, arterial pressure, or contractile state. The hemodynamic changes were transient with a nearly complete return to the control state within 6 h. The adaptation included a diuresis and a decrease in blood volume, associated with ADH, renin, and aldosterone inhibition.

  1. Reinforcement learning for adaptive threshold control of restorative brain-computer interfaces: a Bayesian simulation

    PubMed Central

    Bauer, Robert; Gharabaghi, Alireza

    2015-01-01

    Restorative brain-computer interfaces (BCI) are increasingly used to provide feedback of neuronal states in a bid to normalize pathological brain activity and achieve behavioral gains. However, patients and healthy subjects alike often show a large variability, or even inability, of brain self-regulation for BCI control, known as BCI illiteracy. Although current co-adaptive algorithms are powerful for assistive BCIs, their inherent class switching clashes with the operant conditioning goal of restorative BCIs. Moreover, due to the treatment rationale, the classifier of restorative BCIs usually has a constrained feature space, thus limiting the possibility of classifier adaptation. In this context, we applied a Bayesian model of neurofeedback and reinforcement learning for different threshold selection strategies to study the impact of threshold adaptation of a linear classifier on optimizing restorative BCIs. For each feedback iteration, we first determined the thresholds that result in minimal action entropy and maximal instructional efficiency. We then used the resulting vector for the simulation of continuous threshold adaptation. We could thus show that threshold adaptation can improve reinforcement learning, particularly in cases of BCI illiteracy. Finally, on the basis of information-theory, we provided an explanation for the achieved benefits of adaptive threshold setting. PMID:25729347

  2. Reinforcement learning for adaptive threshold control of restorative brain-computer interfaces: a Bayesian simulation.

    PubMed

    Bauer, Robert; Gharabaghi, Alireza

    2015-01-01

    Restorative brain-computer interfaces (BCI) are increasingly used to provide feedback of neuronal states in a bid to normalize pathological brain activity and achieve behavioral gains. However, patients and healthy subjects alike often show a large variability, or even inability, of brain self-regulation for BCI control, known as BCI illiteracy. Although current co-adaptive algorithms are powerful for assistive BCIs, their inherent class switching clashes with the operant conditioning goal of restorative BCIs. Moreover, due to the treatment rationale, the classifier of restorative BCIs usually has a constrained feature space, thus limiting the possibility of classifier adaptation. In this context, we applied a Bayesian model of neurofeedback and reinforcement learning for different threshold selection strategies to study the impact of threshold adaptation of a linear classifier on optimizing restorative BCIs. For each feedback iteration, we first determined the thresholds that result in minimal action entropy and maximal instructional efficiency. We then used the resulting vector for the simulation of continuous threshold adaptation. We could thus show that threshold adaptation can improve reinforcement learning, particularly in cases of BCI illiteracy. Finally, on the basis of information-theory, we provided an explanation for the achieved benefits of adaptive threshold setting.

  3. Minifactory: a precision assembly system adaptable to the product life cycle

    NASA Astrophysics Data System (ADS)

    Muir, Patrick F.; Rizzi, Alfred A.; Gowdy, Jay W.

    1997-12-01

    Automated product assembly systems are traditionally designed with the intent that they will be operated with few significant changes for as long as the product is being manufactured. This approach to factory design and programming has may undesirable qualities which have motivated the development of more 'flexible' systems. In an effort to improve agility, different types of flexibility have been integrated into factory designs. Specifically, automated assembly systems have been endowed with the ability to assemble differing products by means of computer-controlled robots, and to accommodate variations in parts locations and dimensions by means of sensing. The product life cycle (PLC) is a standard four-stage model of the performance of a product from the time that it is first introduced in the marketplace until the time that it is discontinued. Manufacturers can improve their return on investment by adapting the production process to the PLC. We are developing two concepts to enable manufacturers to more readily achieve this goal: the agile assembly architecture (AAA), an abstract framework for distributed modular automation; and minifactory, our physical instantation of this architecture for the assembly of precision electro-mechanical devices. By examining the requirements which each PLC stage places upon the production system, we identify characteristics of factory design and programming which are appropriate for that stage. As the product transitions from one stage to the next, the factory design and programing should also transition from one embodiment to the next in order to achieve the best return on investment. Modularity of the factory components, highly flexible product transport mechanisms, and a high level of distributed intelligence are key characteristics of minifactory that enable this adaptation.

  4. The adaptive value of morphological, behavioural and life-history traits in reproductive female wolves.

    PubMed

    Stahler, Daniel R; MacNulty, Daniel R; Wayne, Robert K; vonHoldt, Bridgett; Smith, Douglas W

    2013-01-01

    Reproduction in social organisms is shaped by numerous morphological, behavioural and life-history traits such as body size, cooperative breeding and age of reproduction, respectively. Little is known, however, about the relative influence of these different types of traits on reproduction, particularly in the context of environmental conditions that determine their adaptive value. Here, we use 14 years of data from a long-term study of wolves (Canis lupus) in Yellowstone National Park, USA, to evaluate the relative effects of different traits and ecological factors on the reproductive performance (litter size and survival) of breeding females. At the individual level, litter size and survival improved with body mass and declined with age (c. 4-5 years). Grey-coloured females had more surviving pups than black females, which likely contributed to the maintenance of coat colour polymorphism in this system. The effect of pack size on reproductive performance was nonlinear as litter size peaked at eight wolves and then declined, and litter survival increased rapidly up to three wolves, beyond which it increased more gradually. At the population level, litter size and survival decreased with increasing wolf population size and canine distemper outbreaks. The relative influence of these different-level factors on wolf reproductive success followed individual > group > population. Body mass was the primary determinant of litter size, followed by pack size and population size. Body mass was also the main driver of litter survival, followed by pack size and disease. Reproductive gains because of larger body size and cooperative breeding may mitigate reproductive losses because of negative density dependence and disease. These findings highlight the adaptive value of large body size and sociality in promoting individual fitness in stochastic and competitive environments.

  5. 3D design and electric simulation of a silicon drift detector using a spiral biasing adapter

    NASA Astrophysics Data System (ADS)

    Li, Yu-yun; Xiong, Bo; Li, Zheng

    2016-09-01

    The detector system of combining a spiral biasing adapter (SBA) with a silicon drift detector (SBA-SDD) is largely different from the traditional silicon drift detector (SDD), including the spiral SDD. It has a spiral biasing adapter of the same design as a traditional spiral SDD and an SDD with concentric rings having the same radius. Compared with the traditional spiral SDD, the SBA-SDD separates the spiral's functions of biasing adapter and the p-n junction definition. In this paper, the SBA-SDD is simulated using a Sentaurus TCAD tool, which is a full 3D device simulation tool. The simulated electric characteristics include electric potential, electric field, electron concentration, and single event effect. Because of the special design of the SBA-SDD, the SBA can generate an optimum drift electric field in the SDD, comparable with the conventional spiral SDD, while the SDD can be designed with concentric rings to reduce surface area. Also the current and heat generated in the SBA are separated from the SDD. To study the single event response, we simulated the induced current caused by incident heavy ions (20 and 50 μm penetration length) with different linear energy transfer (LET). The SBA-SDD can be used just like a conventional SDD, such as X-ray detector for energy spectroscopy and imaging, etc.

  6. Parameter estimation for chaotic systems using a hybrid adaptive cuckoo search with simulated annealing algorithm.

    PubMed

    Sheng, Zheng; Wang, Jun; Zhou, Shudao; Zhou, Bihua

    2014-03-01

    This paper introduces a novel hybrid optimization algorithm to establish the parameters of chaotic systems. In order to deal with the weaknesses of the traditional cuckoo search algorithm, the proposed adaptive cuckoo search with simulated annealing algorithm is presented, which incorporates the adaptive parameters adjusting operation and the simulated annealing operation in the cuckoo search algorithm. Normally, the parameters of the cuckoo search algorithm are kept constant that may result in decreasing the efficiency of the algorithm. For the purpose of balancing and enhancing the accuracy and convergence rate of the cuckoo search algorithm, the adaptive operation is presented to tune the parameters properly. Besides, the local search capability of cuckoo search algorithm is relatively weak that may decrease the quality of optimization. So the simulated annealing operation is merged into the cuckoo search algorithm to enhance the local search ability and improve the accuracy and reliability of the results. The functionality of the proposed hybrid algorithm is investigated through the Lorenz chaotic system under the noiseless and noise condition, respectively. The numerical results demonstrate that the method can estimate parameters efficiently and accurately in the noiseless and noise condition. Finally, the results are compared with the traditional cuckoo search algorithm, genetic algorithm, and particle swarm optimization algorithm. Simulation results demonstrate the effectiveness and superior performance of the proposed algorithm.

  7. Parameter estimation for chaotic systems using a hybrid adaptive cuckoo search with simulated annealing algorithm

    NASA Astrophysics Data System (ADS)

    Sheng, Zheng; Wang, Jun; Zhou, Shudao; Zhou, Bihua

    2014-03-01

    This paper introduces a novel hybrid optimization algorithm to establish the parameters of chaotic systems. In order to deal with the weaknesses of the traditional cuckoo search algorithm, the proposed adaptive cuckoo search with simulated annealing algorithm is presented, which incorporates the adaptive parameters adjusting operation and the simulated annealing operation in the cuckoo search algorithm. Normally, the parameters of the cuckoo search algorithm are kept constant that may result in decreasing the efficiency of the algorithm. For the purpose of balancing and enhancing the accuracy and convergence rate of the cuckoo search algorithm, the adaptive operation is presented to tune the parameters properly. Besides, the local search capability of cuckoo search algorithm is relatively weak that may decrease the quality of optimization. So the simulated annealing operation is merged into the cuckoo search algorithm to enhance the local search ability and improve the accuracy and reliability of the results. The functionality of the proposed hybrid algorithm is investigated through the Lorenz chaotic system under the noiseless and noise condition, respectively. The numerical results demonstrate that the method can estimate parameters efficiently and accurately in the noiseless and noise condition. Finally, the results are compared with the traditional cuckoo search algorithm, genetic algorithm, and particle swarm optimization algorithm. Simulation results demonstrate the effectiveness and superior performance of the proposed algorithm.

  8. Parameter estimation for chaotic systems using a hybrid adaptive cuckoo search with simulated annealing algorithm

    SciTech Connect

    Sheng, Zheng; Wang, Jun; Zhou, Bihua; Zhou, Shudao

    2014-03-15

    This paper introduces a novel hybrid optimization algorithm to establish the parameters of chaotic systems. In order to deal with the weaknesses of the traditional cuckoo search algorithm, the proposed adaptive cuckoo search with simulated annealing algorithm is presented, which incorporates the adaptive parameters adjusting operation and the simulated annealing operation in the cuckoo search algorithm. Normally, the parameters of the cuckoo search algorithm are kept constant that may result in decreasing the efficiency of the algorithm. For the purpose of balancing and enhancing the accuracy and convergence rate of the cuckoo search algorithm, the adaptive operation is presented to tune the parameters properly. Besides, the local search capability of cuckoo search algorithm is relatively weak that may decrease the quality of optimization. So the simulated annealing operation is merged into the cuckoo search algorithm to enhance the local search ability and improve the accuracy and reliability of the results. The functionality of the proposed hybrid algorithm is investigated through the Lorenz chaotic system under the noiseless and noise condition, respectively. The numerical results demonstrate that the method can estimate parameters efficiently and accurately in the noiseless and noise condition. Finally, the results are compared with the traditional cuckoo search algorithm, genetic algorithm, and particle swarm optimization algorithm. Simulation results demonstrate the effectiveness and superior performance of the proposed algorithm.

  9. Using Structural Equation Modeling to Validate Online Game Players' Motivations Relative to Self-Concept and Life Adaptation

    ERIC Educational Resources Information Center

    Yang, Shu Ching; Huang, Chiao Ling

    2013-01-01

    This study aimed to validate a systematic instrument to measure online players' motivations for playing online games (MPOG) and examine how the interplay of differential motivations impacts young gamers' self-concept and life adaptation. Confirmatory factor analysis determined that a hierarchical model with a two-factor structure of…

  10. The Development of an ICF-Oriented, Adaptive Physician Assessment Instrument of Mobility, Self-care, and Domestic Life

    ERIC Educational Resources Information Center

    Farin, Erik; Fleitz, Annette

    2009-01-01

    The objective of this study was development and psychometric testing of an adaptive, International Classification of Functioning, Disability, and Health (ICF)-oriented questionnaire to be processed by the rehabilitation physician that aids in assessing mobility, self-care, and domestic life (Moses-Physician). The intent is to develop a physician…

  11. Adaptive Flow Simulation of Turbulence in Subject-Specific Abdominal Aortic Aneurysm on Massively Parallel Computers

    NASA Astrophysics Data System (ADS)

    Sahni, Onkar; Jansen, Kenneth; Shephard, Mark; Taylor, Charles

    2007-11-01

    Flow within the healthy human vascular system is typically laminar but diseased conditions can alter the geometry sufficiently to produce transitional/turbulent flows in regions focal (and immediately downstream) of the diseased section. The mean unsteadiness (pulsatile or respiratory cycle) further complicates the situation making traditional turbulence simulation techniques (e.g., Reynolds-averaged Navier-Stokes simulations (RANSS)) suspect. At the other extreme, direct numerical simulation (DNS) while fully appropriate can lead to large computational expense, particularly when the simulations must be done quickly since they are intended to affect the outcome of a medical treatment (e.g., virtual surgical planning). To produce simulations in a clinically relevant time frame requires; 1) adaptive meshing technique that closely matches the desired local mesh resolution in all three directions to the highly anisotropic physical length scales in the flow, 2) efficient solution algorithms, and 3) excellent scaling on massively parallel computers. In this presentation we will demonstrate results for a subject-specific simulation of an abdominal aortic aneurysm using stabilized finite element method on anisotropically adapted meshes consisting of O(10^8) elements over O(10^4) processors.

  12. Aroostook Sunshine: An Educational Simulation about Life in Maine.

    ERIC Educational Resources Information Center

    Association of Aroostook Indians, Houlton, ME.

    Designed for instruction at the secondary level, this curriculum guide focuses on simulated classroom experiences in prejudice and minority race relations and content materials relative to Northeast Woodland American Indian history and culture. Knowledge of the following are cited as major unit objectives: (1) Indian cultural contributions; (2)…

  13. Improving Life Cycle Management Through Simulation and Efficient Design

    DTIC Science & Technology

    2008-09-01

    design, the author uses the orthogonal and nearly orthogonal LH worksheet (Sanchez, 2005) to develop the design points. The worksheet is an Excel ...11 listing each design points. The worksheet is an Excel -based tool developed to ease in the design of large-scale simulation experiments. low...NOLH worksheet design ................................................................22 Figure 5. Two-way input combinations

  14. Artificial Cells: Synthetic Compartments with Life-like Functionality and Adaptivity.

    PubMed

    Buddingh', Bastiaan C; van Hest, Jan C M

    2017-01-17

    Cells are highly advanced microreactors that form the basis of all life. Their fascinating complexity has inspired scientists to create analogs from synthetic and natural components using a bottom-up approach. The ultimate goal here is to assemble a fully man-made cell that displays functionality and adaptivity as advanced as that found in nature, which will not only provide insight into the fundamental processes in natural cells but also pave the way for new applications of such artificial cells. In this Account, we highlight our recent work and that of others on the construction of artificial cells. First, we will introduce the key features that characterize a living system; next, we will discuss how these have been imitated in artificial cells. First, compartmentalization is crucial to separate the inner chemical milieu from the external environment. Current state-of-the-art artificial cells comprise subcompartments to mimic the hierarchical architecture of eukaryotic cells and tissue. Furthermore, synthetic gene circuits have been used to encode genetic information that creates complex behavior like pulses or feedback. Additionally, artificial cells have to reproduce to maintain a population. Controlled growth and fission of synthetic compartments have been demonstrated, but the extensive regulation of cell division in nature is still unmatched. Here, we also point out important challenges the field needs to overcome to realize its full potential. As artificial cells integrate increasing orders of functionality, maintaining a supporting metabolism that can regenerate key metabolites becomes crucial. Furthermore, life does not operate in isolation. Natural cells constantly sense their environment, exchange (chemical) signals, and can move toward a chemoattractant. Here, we specifically explore recent efforts to reproduce such adaptivity in artificial cells. For instance, synthetic compartments have been produced that can recruit proteins to the membrane upon an

  15. Adapting acceptance and commitment therapy for parents of children with life-threatening illness: pilot study.

    PubMed

    Burke, Kylie; Muscara, Frank; McCarthy, Maria; Dimovski, Anica; Hearps, Stephen; Anderson, Vicki; Walser, Robyn

    2014-03-01

    We piloted a novel parent-targeted intervention, Take A Breath (TAB), for parents of children diagnosed with a life-threatening illness (LTI) with the aim of reducing parental distress. Parents were assisted to adapt to their child's diagnosis, treatment, and recovery via TAB's combined acceptance and commitment therapy (ACT) and problem-solving skills training (PSST) approach. Participants were 11 parents of children with a diagnosis of cancer, or who had life-saving cardiac surgery at least 4 months prior. Parents completed questionnaires at pre, post, and 6-month follow-up assessing parent posttraumatic stress symptoms (PTSS), the emotional impact of the child's LTI (e.g., feelings of uncertainty, guilt and sorrow, emotional resources), and psychological elements targeted by the intervention (parental psychological flexibility and mindfulness). Parents reported significant reductions in PTSS and emotional impact from their child's LTI, along with significant improvements in parental psychological flexibility and mindfulness. Effect sizes were medium to large, and improvements were maintained at 6-month follow-up. Our pilot indicates the TAB intervention has promise for preventing or reducing parental distress associated with child LTI and warrants more rigorous evaluation. Although preliminary, these findings suggest that targeting parents' subjective perceptions of their child's LTI may be an effective approach to reducing parental distress. Our results also indicate the potential for such an approach to be adopted across diverse child diagnoses in the acute pediatric setting. Further, our findings provide early indications that ACT combined with PSST is an appropriate therapeutic approach within this context.

  16. [Adaptation and quality of life in anorectal malformation: empirical findings, theoretical concept, Psychometric assessment, and cognitive-behavioral intervention].

    PubMed

    Noeker, Meinolf

    2010-01-01

    Anorectal malformations are inborn developmental defects that are associated with multiple functional Impairments (especially incontinence) and psychosocial burden with a major impact on body schema and self-esteem. Child psychology and psychiatry research begin to identify disorder-dependent and -independent risk and protective factors that predict the outcome of psychological adaptation and quality of life. The present paper analyses the interference of structural and functional disease parameters with the achievement of regular developmental tasks, presents a hypothetical conceptual framework concerning the development of psychological adaptation and quality of life in ARM, integrates findings from empirical research with the framework presented and outlines strategies of psychological support from a cognitive-behavioural perspective within a multidisciplinary treatment approach to enhance medical, functional, and psychosocial quality of life.

  17. Image-guided adaptive gating of lung cancer radiotherapy: a computer simulation study

    NASA Astrophysics Data System (ADS)

    Aristophanous, Michalis; Rottmann, Joerg; Park, Sang-June; Nishioka, Seiko; Shirato, Hiroki; Berbeco, Ross I.

    2010-08-01

    The purpose of this study is to investigate the effect that image-guided adaptation of the gating window during treatment could have on the residual tumor motion, by simulating different gated radiotherapy techniques. There are three separate components of this simulation: (1) the 'Hokkaido Data', which are previously measured 3D data of lung tumor motion tracks and the corresponding 1D respiratory signals obtained during the entire ungated radiotherapy treatments of eight patients, (2) the respiratory gating protocol at our institution and the imaging performed under that protocol and (3) the actual simulation in which the Hokkaido Data are used to select tumor position information that could have been collected based on the imaging performed under our gating protocol. We simulated treatments with a fixed gating window and a gating window that is updated during treatment. The patient data were divided into different fractions, each with continuous acquisitions longer than 2 min. In accordance to the imaging performed under our gating protocol, we assume that we have tumor position information for the first 15 s of treatment, obtained from kV fluoroscopy, and for the rest of the fractions the tumor position is only available during the beam-on time from MV imaging. The gating window was set according to the information obtained from the first 15 s such that the residual motion was less than 3 mm. For the fixed gating window technique the gate remained the same for the entire treatment, while for the adaptive technique the range of the tumor motion during beam-on time was measured and used to adapt the gating window to keep the residual motion below 3 mm. The algorithm used to adapt the gating window is described. The residual tumor motion inside the gating window was reduced on average by 24% for the patients with regular breathing patterns and the difference was statistically significant (p-value = 0.01). The magnitude of the residual tumor motion depended on the

  18. Life-history evolution at the molecular level: adaptive amino acid composition of avian vitellogenins

    PubMed Central

    Hughes, Austin L.

    2015-01-01

    Avian genomes typically encode three distinct vitellogenin (VTG) egg yolk proteins (VTG1, VTG2 and VTG3), which arose by gene duplication prior to the most recent common ancestor of birds. Analysis of VTG sequences from 34 avian species in a phylogenetic framework supported the hypothesis that VTG amino acid composition has co-evolved with embryo incubation time. Embryo incubation time was positively correlated with the proportions of dietary essential amino acids (EAAs) in VTG1 and VTG2, and with the proportion of sulfur-containing amino acids in VTG3. These patterns were seen even when only semi-altricial and/or altricial species were considered, suggesting that the duration of embryo incubation is a major selective factor on the amino acid composition of VTGs, rather than developmental mode alone. The results are consistent with the hypothesis that the level of EAAs provided to the egg represents an adaptation to the loss of amino acids through breakdown over the course of incubation and imply that life-history phenotypes and VTG amino acid composition have co-evolved throughout the evolutionary history of birds. PMID:26224713

  19. Comparison of life cycle emissions and energy consumption for environmentally adapted metalworking fluid systems.

    PubMed

    Clarens, Andres F; Zimmerman, Julie B; Keoleian, Greg A; Hayes, Kim F; Skerlos, Steven J

    2008-11-15

    A number of environmentally adapted lubricants have been proposed in response to the environmental and health impacts of metalworking fluids (MWFs). The alternatives typically substitute petroleum with vegetable-based components and/or deliver minimum quantities of lubricant in gas rather than water, with the former strategy being more prevalent than the latter. A comparative life cycle assessment of water- and gas-based systems has shown that delivery of lubricants in air rather than water can reduce solid waste by 60%, water use by 90%, and aquatic toxicity by 80%, while virtually eliminating occupational health concerns. However, air-delivery of lubricants cannot be used for severe machining operations due to limitations of cooling and lubricant delivery. For such operations, lubricants delivered in supercritical carbon dioxide (scCO2) are effective while maintaining the health and environmental advantages of air-based systems. Although delivery conditions were found to significantly influence the environmental burdens of all fluids, energy consumption was relatively constant under expected operating conditions. Global warming potential (GWP) increased when delivering lubricants in gas rather than water though all classes of MWFs have low GWP compared with other factory operations. It is therefore concluded that the possibility of increased GWP when switching to gas-based MWFs is a reasonable tradeoff for definite and large reductions in aquatic toxicity, water use, solid waste, and occupational health risks.

  20. A New Simulation Technique for Study of Collisionless Shocks: Self-Adaptive Simulations

    SciTech Connect

    Karimabadi, H.; Omelchenko, Y.; Driscoll, J.; Krauss-Varban, D.; Fujimoto, R.; Perumalla, K.

    2005-08-01

    The traditional technique for simulating physical systems modeled by partial differential equations is by means of time-stepping methodology where the state of the system is updated at regular discrete time intervals. This method has inherent inefficiencies. In contrast to this methodology, we have developed a new asynchronous type of simulation based on a discrete-event-driven (as opposed to time-driven) approach, where the simulation state is updated on a 'need-to-be-done-only' basis. Here we report on this new technique, show an example of particle acceleration in a fast magnetosonic shockwave, and briefly discuss additional issues that we are addressing concerning algorithm development and parallel execution.

  1. Orthogonal Metal Cutting Simulation Using Advanced Constitutive Equations with Damage and Fully Adaptive Numerical Procedure

    NASA Astrophysics Data System (ADS)

    Saanouni, Kkemais; Labergère, Carl; Issa, Mazen; Rassineux, Alain

    2010-06-01

    This work proposes a complete adaptive numerical methodology which uses `advanced' elastoplastic constitutive equations coupling: thermal effects, large elasto-viscoplasticity with mixed non linear hardening, ductile damage and contact with friction, for 2D machining simulation. Fully coupled (strong coupling) thermo-elasto-visco-plastic-damage constitutive equations based on the state variables under large plastic deformation developed for metal forming simulation are presented. The relevant numerical aspects concerning the local integration scheme as well as the global resolution strategy and the adaptive remeshing facility are briefly discussed. Applications are made to the orthogonal metal cutting by chip formation and segmentation under high velocity. The interactions between hardening, plasticity, ductile damage and thermal effects and their effects on the adiabatic shear band formation including the formation of cracks are investigated.

  2. AN AGENT-BASED SIMULATION STUDY OF A COMPLEX ADAPTIVE COLLABORATION NETWORK

    SciTech Connect

    Ozmen, Ozgur; Smith, Jeffrey; Yilmaz, Levent

    2013-01-01

    One of the most significant problems in organizational scholarship is to discern how social collectives govern, organize, and coordinate the actions of individuals to achieve collective outcomes. The collectives are usually interpreted as complex adaptive systems (CAS). The understanding of CAS is more likely to arise with the help of computer-based simulations. In this tutorial, using agent-based modeling approach, a complex adaptive social communication network model is introduced. The objective is to present the underlying dynamics of the system in a form of computer simulation that enables analyzing the impacts of various mechanisms on network topologies and emergent behaviors. The ultimate goal is to further our understanding of the dynamics in the system and facilitate developing informed policies for decision-makers.

  3. Scale-adaptive simulation of a hot jet in cross flow

    NASA Astrophysics Data System (ADS)

    Duda, B. M.; Menter, F. R.; Hansen, T.; Esteve, M.-J.

    2011-12-01

    The simulation of a hot jet in cross flow is of crucial interest for the aircraft industry as it directly impacts aircraft safety and global performance. Due to the highly transient and turbulent character of this flow, simulation strategies are necessary that resolve at least a part of the turbulence spectrum. The high Reynolds numbers for realistic aircraft applications do not permit the use of pure Large Eddy Simulations as the spatial and temporal resolution requirements for wall bounded flows are prohibitive in an industrial design process. For this reason, the hybrid approach of the Scale-Adaptive Simulation is employed, which retains attached boundary layers in well-established RANS regime and allows the resolution of turbulent fluctuations in areas with sufficient flow instabilities and grid refinement. To evaluate the influence of the underlying numerical grid, three meshing strategies are investigated and the results are validated against experimental data.

  4. Predictive wind turbine simulation with an adaptive lattice Boltzmann method for moving boundaries

    NASA Astrophysics Data System (ADS)

    Deiterding, Ralf; Wood, Stephen L.

    2016-09-01

    Operating horizontal axis wind turbines create large-scale turbulent wake structures that affect the power output of downwind turbines considerably. The computational prediction of this phenomenon is challenging as efficient low dissipation schemes are necessary that represent the vorticity production by the moving structures accurately and that are able to transport wakes without significant artificial decay over distances of several rotor diameters. We have developed a parallel adaptive lattice Boltzmann method for large eddy simulation of turbulent weakly compressible flows with embedded moving structures that considers these requirements rather naturally and enables first principle simulations of wake-turbine interaction phenomena at reasonable computational costs. The paper describes the employed computational techniques and presents validation simulations for the Mexnext benchmark experiments as well as simulations of the wake propagation in the Scaled Wind Farm Technology (SWIFT) array consisting of three Vestas V27 turbines in triangular arrangement.

  5. Negotiated meanings of disability simulations in an adapted physical activity course: learning from student reflections.

    PubMed

    Leo, Jennifer; Goodwin, Donna

    2014-04-01

    Disability simulations have been used as a pedagogical tool to simulate the functional and cultural experiences of disability. Despite their widespread application, disagreement about their ethical use, value, and efficacy persists. The purpose of this study was to understand how postsecondary kinesiology students experienced participation in disability simulations. An interpretative phenomenological approach guided the study's collection of journal entries and clarifying one-on-one interviews with four female undergraduate students enrolled in a required adapted physical activity course. The data were analyzed thematically and interpreted using the conceptual framework of situated learning. Three themes transpired: unnerving visibility, negotiating environments differently, and tomorrow I'll be fine. The students described emotional responses to the use of wheelchairs as disability artifacts, developed awareness of environmental barriers to culturally and socially normative activities, and moderated their discomfort with the knowledge they could end the simulation at any time.

  6. Effect of Repeated Simulated Disinfections by Microwave Energy on the Complete Denture Base Adaptation

    PubMed Central

    Consani, Rafael L.X.; Iwasaki, Rose Y; Mesquita, Marcelo F; Mendes, Wilson B; Consani, Simonides

    2008-01-01

    This study evaluated the effect of repeated microwave disinfections on the adaptation of the maxillar denture base using 2 different flask closure methods. Twenty stone cast-wax base sets were prepared for flasking by traditional cramp or RS system methods. Five bases for each method were submitted to 5 repeated simulated disinfections in a microwave oven with 650W for 3 minutes. Control bases were not disinfected. Three transverse cuts were made through each stone cast-resin base set, corresponding to canine, first molar, and posterior region. Measurements were made using an optical micrometer at 5 points for each cut to determine base adaptation: left and right marginal limits of the flanges, left and right ridge crests, and midline. Results for base adaptation performed by the flask closure methods were: traditional cramp (non-disinfected = 0.21 ± 0.05mm and disinfected = 0.22 ± 0.05mm), and RS system (non-disinfected = 0.16 ± 0.05 and disinfected = 0.17 ± 0.04mm). Collected data were submitted to ANOVA and Tukey test (α=.05). Repeated simulated disinfections by microwave energy did not cause deleterious effect on the base adaptation, when the traditional cramp and RS system flask closure methods were compared. PMID:19088884

  7. Simulation of macromolecular liquids with the adaptive resolution molecular dynamics technique

    NASA Astrophysics Data System (ADS)

    Peters, J. H.; Klein, R.; Delle Site, L.

    2016-08-01

    We extend the application of the adaptive resolution technique (AdResS) to liquid systems composed of alkane chains of different lengths. The aim of the study is to develop and test the modifications of AdResS required in order to handle the change of representation of large molecules. The robustness of the approach is shown by calculating several relevant structural properties and comparing them with the results of full atomistic simulations. The extended scheme represents a robust prototype for the simulation of macromolecular systems of interest in several fields, from material science to biophysics.

  8. Parallel adaptive Cartesian upwind methods for shock-driven multiphysics simulation

    SciTech Connect

    Deiterding, Ralf

    2011-01-01

    The multiphysics fluid-structure interaction simulation of shock-loaded thin-walled structures requires the dynamic coupling of a shock-capturing flow solver to a solid mechanics solver for large deformations. By combining a Cartesian embedded boundary approach with dynamic mesh adaptation a generic software framework for such flow solvers has been constructed that allows easy exchange of the specific hydrodynamic finite volume upwind scheme and coupling to various explicit finite element solid dynamics solvers. The paper gives an overview of the computational approach and presents first simulations that couple the software to the general purpose solid dynamics code DYNA3D.

  9. Discrete event simulation as a tool in optimization of a professional complex adaptive system.

    PubMed

    Nielsen, Anders Lassen; Hilwig, Helmer; Kissoon, Niranjan; Teelucksingh, Surujpal

    2008-01-01

    Similar urgent needs for improvement of health care systems exist in the developed and developing world. The culture and the organization of an emergency department in developing countries can best be described as a professional complex adaptive system, where each agent (employee) are ignorant of the behavior of the system as a whole; no one understands the entire system. Each agent's action is based on the state of the system at the moment (i.e. lack of medicine, unavailable laboratory investigation, lack of beds and lack of staff in certain functions). An important question is how one can improve the emergency service within the given constraints. The use of simulation signals is one new approach in studying issues amenable to improvement. Discrete event simulation was used to simulate part of the patient flow in an emergency department. A simple model was built using a prototyping approach. The simulation showed that a minor rotation among the nurses could reduce the mean number of visitors that had to be refereed to alternative flows within the hospital from 87 to 37 on a daily basis with a mean utilization of the staff between 95.8% (the nurses) and 87.4% (the doctors). We conclude that even faced with resource constraints and lack of accessible data discrete event simulation is a tool that can be used successfully to study the consequences of changes in very complex and self organizing professional complex adaptive systems.

  10. Neural and Behavioral Evidence for the Role of Mental Simulation in Meaning in Life

    PubMed Central

    Waytz, Adam; Hershfield, Hal E; Tamir, Diana I

    2014-01-01

    Mental simulation, the process of self-projection into alternate temporal, spatial, social, or hypothetical realities is a distinctively human capacity. Numerous lines of research also suggest that the tendency for mental simulation is associated with enhanced meaning. The present research tests this association specifically examining the relationship between two forms of simulation (temporal and spatial) and meaning in life. Study 1 uses neuroimaging to demonstrate that enhanced connectivity in the medial temporal lobe network, a subnetwork of the brain’s default network implicated in prospection and retrospection, correlates with self-reported meaning in life. Study 2 demonstrates that experimentally inducing people to think about the past or future versus the present enhances self-reported meaning in life, through the generation of more meaningful events. Study 3 demonstrates that experimentally inducing people to think specifically versus generally about the past or future enhances self-reported meaning in life. Study 4 turns to spatial simulation to demonstrate that experimentally inducing people to think specifically about an alternate spatial location (from the present) increases meaning derived from this simulation compared to thinking generally about another location or specifically about one’s present location. Study 5 demonstrates that experimentally inducing people to think about an alternate spatial location versus one’s present location enhances meaning in life, through meaning derived from this simulation. Study 6 demonstrates that simply asking people to imagine completing a measure of meaning in life in an alternate location compared to asking them to do so in their present location enhances reports of meaning. This research sheds light on an important determinant of meaning in life and suggests that undirected mental simulation benefits psychological well-being. PMID:25603379

  11. Application of nonlinear adaptive motion washout to transport ground-handling simulation

    NASA Technical Reports Server (NTRS)

    Parrish, R. V.; Martin, D. J., Jr.

    1983-01-01

    The application of a nonlinear coordinated adaptive motion washout to the transport ground-handling environment is documented. Additions to both the aircraft math model and the motion washout system are discussed. The additions to the simulated-aircraft math model provided improved modeling fidelity for braking and reverse-thrust application, and the additions to the motion-base washout system allowed transition from the desired flight parameters to the less restrictive ground parameters of the washout.

  12. Adaptive, High-Order, and Scalable Software Elements for Dynamic Rupture Simulations in Complex Geometries

    NASA Astrophysics Data System (ADS)

    Kozdon, J. E.; Wilcox, L.; Aranda, A. R.

    2014-12-01

    The goal of this work is to develop a new set of simulation tools for earthquake rupture dynamics based on state-of-the-art high-order, adaptive numerical methods capable of handling complex geometries. High-order methods are ideal for earthquake rupture simulations as the problems are wave-dominated and the waves excited in simulations propagate over distance much larger than their fundamental wavelength. When high-order methods are used for such problems significantly fewer degrees of freedom are required as compared with low-order methods. The base numerical method in our new software elements is a discontinuous Galerkin method based on curved, Kronecker product hexahedral elements. We currently use MPI for off-node parallelism and are in the process of exploring strategies for on-node parallelism. Spatial mesh adaptivity is handled using the p4est library and temporal adaptivity is achieved through an Adams-Bashforth based local time stepping method; we are presently in the process of including dynamic spatial adaptivity which we believe will be valuable for capturing the small-scale features around the propagating rupture front. One of the key features of our software elements is that the method is provably stable, even after the inclusion of the nonlinear frictions laws which govern rupture dynamics. In this presentation we will both outline the structure of the software elements as well as validate the rupture dynamics with SCEC benchmark test problems. We are also presently developing several realistic simulation geometries which may also be reported on. Finally, the software elements that we have designed are fully public domain and have been designed with tightly coupled, wave dominated multiphysics applications in mind. This latter design decisions means the software elements are applicable to many other geophysical and non-geophysical applications.

  13. Adaptive particle-cell algorithm for Fokker-Planck based rarefied gas flow simulations

    NASA Astrophysics Data System (ADS)

    Pfeiffer, M.; Gorji, M. H.

    2017-04-01

    Recently, the Fokker-Planck (FP) kinetic model has been devised on the basis of the Boltzmann equation (Jenny et al., 2010; Gorji et al., 2011). Particle Monte-Carlo schemes are then introduced for simulations of rarefied gas flows based on the FP kinetics. Here the particles follow independent stochastic paths and thus a spatio-temporal resolution coarser than the collisional scales becomes possible. In contrast to the direct simulation Monte-Carlo (DSMC), the computational cost is independent of the Knudsen number resulting in efficient simulations at moderate/low Knudsen flows. In order to further exploit the efficiency of the FP method, the required particle-cell resolutions should be found, and a cell refinement strategy has to be developed accordingly. In this study, an adaptive particle-cell scheme applicable to a general unstructured mesh is derived for the FP model. Virtual sub cells are introduced for the adaptive mesh refinement. Moreover a sub cell-merging algorithm is provided to honor the minimum required number of particles per cell. For assessments, the 70 degree blunted cone reentry flow (Allgre et al., 1997) is studied. Excellent agreement between the introduced adaptive FP method and DSMC is achieved.

  14. Aeroacoustic Simulation of Nose Landing Gear on Adaptive Unstructured Grids With FUN3D

    NASA Technical Reports Server (NTRS)

    Vatsa, Veer N.; Khorrami, Mehdi R.; Park, Michael A.; Lockhard, David P.

    2013-01-01

    Numerical simulations have been performed for a partially-dressed, cavity-closed nose landing gear configuration that was tested in NASA Langley s closed-wall Basic Aerodynamic Research Tunnel (BART) and in the University of Florida's open-jet acoustic facility known as the UFAFF. The unstructured-grid flow solver FUN3D, developed at NASA Langley Research center, is used to compute the unsteady flow field for this configuration. Starting with a coarse grid, a series of successively finer grids were generated using the adaptive gridding methodology available in the FUN3D code. A hybrid Reynolds-averaged Navier-Stokes/large eddy simulation (RANS/LES) turbulence model is used for these computations. Time-averaged and instantaneous solutions obtained on these grids are compared with the measured data. In general, the correlation with the experimental data improves with grid refinement. A similar trend is observed for sound pressure levels obtained by using these CFD solutions as input to a FfowcsWilliams-Hawkings noise propagation code to compute the farfield noise levels. In general, the numerical solutions obtained on adapted grids compare well with the hand-tuned enriched fine grid solutions and experimental data. In addition, the grid adaption strategy discussed here simplifies the grid generation process, and results in improved computational efficiency of CFD simulations.

  15. An Adaptive Recurrent Neural Network for Remaining Useful Life Prediction of Lithium-ion Batteries

    DTIC Science & Technology

    2010-10-01

    be scheduled in advance when needed. In this paper, an adaptive recurrent neural network (ARNN) is proposed for system dynamic state forecasting. The...developed ARNN is constructed based on the adaptive/recurrent neural network architecture and the network weights are adaptively optimized using the

  16. Annual Research Review: The Neurobiology and Physiology of Resilience and Adaptation across the Life Course

    ERIC Educational Resources Information Center

    Karatoreos, Ilia N.; McEwen, Bruce S.

    2013-01-01

    Background: Adaptation is key to survival. An organism must adapt to environmental challenges in order to be able to thrive in the environment in which they find themselves. Resilience can be thought of as a measure of the ability of an organism to adapt, and to withstand challenges to its stability. In higher animals, the brain is a key player in…

  17. Adapt

    NASA Astrophysics Data System (ADS)

    Bargatze, L. F.

    2015-12-01

    Active Data Archive Product Tracking (ADAPT) is a collection of software routines that permits one to generate XML metadata files to describe and register data products in support of the NASA Heliophysics Virtual Observatory VxO effort. ADAPT is also a philosophy. The ADAPT concept is to use any and all available metadata associated with scientific data to produce XML metadata descriptions in a consistent, uniform, and organized fashion to provide blanket access to the full complement of data stored on a targeted data server. In this poster, we present an application of ADAPT to describe all of the data products that are stored by using the Common Data File (CDF) format served out by the CDAWEB and SPDF data servers hosted at the NASA Goddard Space Flight Center. These data servers are the primary repositories for NASA Heliophysics data. For this purpose, the ADAPT routines have been used to generate data resource descriptions by using an XML schema named Space Physics Archive, Search, and Extract (SPASE). SPASE is the designated standard for documenting Heliophysics data products, as adopted by the Heliophysics Data and Model Consortium. The set of SPASE XML resource descriptions produced by ADAPT includes high-level descriptions of numerical data products, display data products, or catalogs and also includes low-level "Granule" descriptions. A SPASE Granule is effectively a universal access metadata resource; a Granule associates an individual data file (e.g. a CDF file) with a "parent" high-level data resource description, assigns a resource identifier to the file, and lists the corresponding assess URL(s). The CDAWEB and SPDF file systems were queried to provide the input required by the ADAPT software to create an initial set of SPASE metadata resource descriptions. Then, the CDAWEB and SPDF data repositories were queried subsequently on a nightly basis and the CDF file lists were checked for any changes such as the occurrence of new, modified, or deleted

  18. Time scale matters: genetic analysis does not support adaptation-by-time as the mechanism for adaptive seasonal declines in kokanee reproductive life span

    PubMed Central

    Morbey, Yolanda E; Jensen, Evelyn L; Russello, Michael A

    2014-01-01

    Seasonal declines of fitness-related traits are often attributed to environmental effects or individual-level decisions about reproductive timing and effort, but genetic variation may also play a role. In populations of Pacific salmon (Oncorhynchus spp.), seasonal declines in reproductive life span have been attributed to adaptation-by-time, in which divergent selection for different traits occurs among reproductively isolated temporal components of a population. We evaluated this hypothesis in kokanee (freshwater obligate Oncorhynchus nerka) by testing for temporal genetic structure in neutral and circadian-linked loci. We detected no genetic differences in presumably neutral loci among kokanee with different arrival and maturation dates within a spawning season. Similarly, we detected no temporal genetic structure in OtsClock1b, Omy1009uw, or OmyFbxw11, candidate loci associated with circadian function. The genetic evidence from this study and others indicates a lack of support for adaptation-by-time as an important evolutionary mechanism underlying seasonal declines in reproductive life span and a need for greater consideration of other mechanisms such as time-dependent, adaptive adjustment of reproductive effort. PMID:25478160

  19. A highly pleiotropic amino acid polymorphism in the Drosophila insulin receptor contributes to life-history adaptation

    PubMed Central

    Paaby, Annalise B.; Bergland, Alan O.; Behrman, Emily L.; Schmidt, Paul S.

    2016-01-01

    Finding the specific nucleotides that underlie adaptive variation is a major goal in evolutionary biology, but polygenic traits pose a challenge because the complex genotype–phenotype relationship can obscure the effects of individual alleles. However, natural selection working in large wild populations can shift allele frequencies and indicate functional regions of the genome. Previously, we showed that the two most common alleles of a complex amino acid insertion–deletion polymorphism in the Drosophila insulin receptor show independent, parallel clines in frequency across the North American and Australian continents. Here, we report that the cline is stable over at least a five-year period and that the polymorphism also demonstrates temporal shifts in allele frequency concurrent with seasonal change. We tested the alleles for effects on levels of insulin signaling, fecundity, development time, body size, stress tolerance, and life span. We find that the alleles are associated with predictable differences in these traits, consistent with patterns of Drosophila life-history variation across geography that likely reflect adaptation to the heterogeneous climatic environment. These results implicate insulin signaling as a major mediator of life-history adaptation in Drosophila, and suggest that life-history trade-offs can be explained by extensive pleiotropy at a single locus. PMID:25319083

  20. Survival thresholds and mortality rates in adaptive dynamics: conciliating deterministic and stochastic simulations.

    PubMed

    Perthame, Benoît; Gauduchon, Mathias

    2010-09-01

    Deterministic population models for adaptive dynamics are derived mathematically from individual-centred stochastic models in the limit of large populations. However, it is common that numerical simulations of both models fit poorly and give rather different behaviours in terms of evolution speeds and branching patterns. Stochastic simulations involve extinction phenomenon operating through demographic stochasticity, when the number of individual 'units' is small. Focusing on the class of integro-differential adaptive models, we include a similar notion in the deterministic formulations, a survival threshold, which allows phenotypical traits in the population to vanish when represented by few 'individuals'. Based on numerical simulations, we show that the survival threshold changes drastically the solution; (i) the evolution speed is much slower, (ii) the branching patterns are reduced continuously and (iii) these patterns are comparable to those obtained with stochastic simulations. The rescaled models can also be analysed theoretically. One can recover the concentration phenomena on well-separated Dirac masses through the constrained Hamilton-Jacobi equation in the limit of small mutations and large observation times.

  1. Accurate and general treatment of electrostatic interaction in Hamiltonian adaptive resolution simulations

    NASA Astrophysics Data System (ADS)

    Heidari, M.; Cortes-Huerto, R.; Donadio, D.; Potestio, R.

    2016-10-01

    In adaptive resolution simulations the same system is concurrently modeled with different resolution in different subdomains of the simulation box, thereby enabling an accurate description in a small but relevant region, while the rest is treated with a computationally parsimonious model. In this framework, electrostatic interaction, whose accurate treatment is a crucial aspect in the realistic modeling of soft matter and biological systems, represents a particularly acute problem due to the intrinsic long-range nature of Coulomb potential. In the present work we propose and validate the usage of a short-range modification of Coulomb potential, the Damped shifted force (DSF) model, in the context of the Hamiltonian adaptive resolution simulation (H-AdResS) scheme. This approach, which is here validated on bulk water, ensures a reliable reproduction of the structural and dynamical properties of the liquid, and enables a seamless embedding in the H-AdResS framework. The resulting dual-resolution setup is implemented in the LAMMPS simulation package, and its customized version employed in the present work is made publicly available.

  2. Parallel grid library with adaptive mesh refinement for development of highly scalable simulations

    NASA Astrophysics Data System (ADS)

    Honkonen, I.; von Alfthan, S.; Sandroos, A.; Janhunen, P.; Palmroth, M.

    2012-04-01

    As the single CPU core performance is saturating while the number of cores in the fastest supercomputers increases exponentially, the parallel performance of simulations on distributed memory machines is crucial. At the same time, utilizing efficiently the large number of available cores presents a challenge, especially in simulations with run-time adaptive mesh refinement. We have developed a generic grid library (dccrg) aimed at finite volume simulations that is easy to use and scales well up to tens of thousands of cores. The grid has several attractive features: It 1) allows an arbitrary C++ class or structure to be used as cell data; 2) provides a simple interface for adaptive mesh refinement during a simulation; 3) encapsulates the details of MPI communication when updating the data of neighboring cells between processes; and 4) provides a simple interface to run-time load balancing, e.g. domain decomposition, through the Zoltan library. Dccrg is freely available for anyone to use, study and modify under the GNU Lesser General Public License v3. We will present the implementation of dccrg, simple and advanced usage examples and scalability results on various supercomputers and problems.

  3. Adaptive Resolution Simulation of Supramolecular Water: The Concurrent Making, Breaking, and Remaking of Water Bundles.

    PubMed

    Zavadlav, Julija; Marrink, Siewert J; Praprotnik, Matej

    2016-08-09

    The adaptive resolution scheme (AdResS) is a multiscale molecular dynamics simulation approach that can concurrently couple atomistic (AT) and coarse-grained (CG) resolution regions, i.e., the molecules can freely adapt their resolution according to their current position in the system. Coupling to supramolecular CG models, where several molecules are represented as a single CG bead, is challenging, but it provides higher computational gains and connection to the established MARTINI CG force field. Difficulties that arise from such coupling have been so far bypassed with bundled AT water models, where additional harmonic bonds between oxygen atoms within a given supramolecular water bundle are introduced. While these models simplify the supramolecular coupling, they also cause in certain situations spurious artifacts, such as partial unfolding of biomolecules. In this work, we present a new clustering algorithm SWINGER that can concurrently make, break, and remake water bundles and in conjunction with the AdResS permits the use of original AT water models. We apply our approach to simulate a hybrid SPC/MARTINI water system and show that the essential properties of water are correctly reproduced with respect to the standard monoscale simulations. The developed hybrid water model can be used in biomolecular simulations, where a significant speed up can be obtained without compromising the accuracy of the AT water model.

  4. Adaptive Resolution Simulation of Supramolecular Water: The Concurrent Making, Breaking, and Remaking of Water Bundles

    PubMed Central

    2016-01-01

    The adaptive resolution scheme (AdResS) is a multiscale molecular dynamics simulation approach that can concurrently couple atomistic (AT) and coarse-grained (CG) resolution regions, i.e., the molecules can freely adapt their resolution according to their current position in the system. Coupling to supramolecular CG models, where several molecules are represented as a single CG bead, is challenging, but it provides higher computational gains and connection to the established MARTINI CG force field. Difficulties that arise from such coupling have been so far bypassed with bundled AT water models, where additional harmonic bonds between oxygen atoms within a given supramolecular water bundle are introduced. While these models simplify the supramolecular coupling, they also cause in certain situations spurious artifacts, such as partial unfolding of biomolecules. In this work, we present a new clustering algorithm SWINGER that can concurrently make, break, and remake water bundles and in conjunction with the AdResS permits the use of original AT water models. We apply our approach to simulate a hybrid SPC/MARTINI water system and show that the essential properties of water are correctly reproduced with respect to the standard monoscale simulations. The developed hybrid water model can be used in biomolecular simulations, where a significant speed up can be obtained without compromising the accuracy of the AT water model. PMID:27409519

  5. Quality of Life and Symptom Burden among Long Term Lung Cancer Survivors: Changing and Adapting

    PubMed Central

    Yang, Ping; Cheville, Andrea L.; Wampfler, Jason A.; Garces, Yolanda I.; Jatoi, Aminah; Clark, Matthew M.; Cassivi, Stephen D.; Midthun, David E.; Marks, Randolph S.; Aubry, Marie-Christine; Okuno, Scott H.; Williams, Brent A.; Nichols, Francis C.; Trastek, Victor F.; Sugimura, Hiroshi; Sarna, Linda; Allen, Mark S.; Deschamps, Claude; Sloan, Jeff A.

    2011-01-01

    Introduction Information is limited regarding health-related quality of life (QOL) status of long term (greater than five years) lung cancer survivors (LTLCS). Obtaining knowledge about their QOL changes over time is a critical step towards improving poor and maintaining good QOL. The primary aim of this study was to conduct a seven-year longitudinal study in survivors of primary lung cancer that identified factors associated with either decline or improvement in QOL over time. Methods Between 1997 and 2003, 447 LTLCS were identified and followed through 2007 using validated questionnaires; data on overall QOL and specific symptoms were at two periods: short-term (less than three years) and long-term post diagnosis. The main analyses were of clinically significant changes (greater than 10%) and factors associated with overall QOL and symptom burden for each period and for changes over time. Results Three hundred two (68%) underwent surgical resection only and 122 (27%) received surgical resection and radiation/chemotherapy. Recurrent or new lung malignancies were observed in 84 (19%) survivors. Significant decline or improvement in overall QOL over time were reported in 155 (35%) and 67 (15%) of 447 survivors, respectively. Among the 155 whose QOL declined, significantly worsened symptoms were fatigue (69%), pain (59%), dyspnea (58%), depressed appetite (49%), and coughing (42%). The symptom burden did not lessen among the 67 who reported improvement, suggesting survivors had adapted to their compromised physical condition. Conclusions LTLCS suffered substantial symptom burden that significantly impaired their QOL, indicating a need for targeted interventions to alleviate their symptoms. PMID:22134070

  6. Psychological adaptation to life-threatening injury in dyads: the role of dysfunctional disclosure of trauma

    PubMed Central

    Pielmaier, Laura; Maercker, Andreas

    2011-01-01

    Background Certain modes of trauma disclosure have been found to be associated with more severe symptoms of posttraumatic stress (PTS) in different trauma populations: the reluctance to disclose trauma-related thoughts and feelings, a strong urge to talk about it, and physical as well as emotional reactions during disclosure. Although social-contextual influences gain more and more interest in trauma research, no study has yet investigated these “dysfunctional disclosure tendencies” and their association with PTS from an interpersonal perspective. Objective (1) To replicate previous findings on dysfunctional disclosure tendencies in patients with life-threatening injury and their significant others and (2) to study interpersonal associations between dysfunctional disclosure style and PTS at a dyadic level. Method PTS symptom severity and self-reports on dysfunctional disclosure tendencies were assessed in N=70 dyads comprising one individual with severe traumatic brain injury and a significant other (“proxy”) 3 months after injury. Results Regression analyses predicting PTS symptom severity revealed dysfunctional disclosure tendencies to have incremental validity above and beyond sex, age, and trauma severity within the individual (both patient and proxy), with moderate effect sizes. The interaction between patient's and proxy's disclosure style explained additional portions of the variance in patients’ PTS symptom severity. Conclusions Findings suggest that dysfunctional disclosure tendencies are related to poorer psychological adaptation to severe traumatic brain injury. This intrapersonal association may be exacerbated by dysfunctional disclosure tendencies on the part of a significant other. Although the results require replication in other trauma samples without brain injury to further generalize the findings beyond the observed population, the study contributes to the expanding literature on the crucial role of interpersonal relationships in trauma

  7. [The paths get shorter. Pastoral nomadism as an adapted way of life in deserts].

    PubMed

    Schwartz, H J; Schwartz, S

    1981-11-27

    Pastoral nomadism, as a way of life adapted to marginally exploitable land and climatic conditions, is the sole chance for using the desert to support people. Nonetheless, this lifestyle has suffered great harm in the last 2 decades and has come under fire from experts as a non-productive and environmentally damaging type of economy. This attitude however ignores the historical viability of this system which has been used for thousands of years. It is estimated that 350 million individuals worldwide live in the so-called savannah-ecosystem, i.e. on natural grassland. Roughly 1/5 are nomadic herders; half of them, 45 million, live in Africa south of the Sahara, and use more than 1/3 of the total area of the continent. Losses of available land since the late 1940s due to growth of agriculturally-oriented population groups, the concomitant increase in cultivated land, and establishment of natural parks and wildlife preserves have greatly restricted seasonal migration of nomads and their herds. This in turn has degraded pasturage from overgrazing. The final result is a deadly spiral of shrinking pasture and increasing usage of the remaining land. Ultimately vegetation is totally destroyed by this kind of pressure. Although land regeneration potential is high, it cannot withstand continuous burdens of this magnitude. Thus pastoral nomadism in Africa is almost extinct in its mature and intact forms. This reduced system is self-destructive and is no longer viable. In view of the critical food shortage in Africa, efforts should be made to re-establish a more viable, fully nomadic system linked to national markets and social services.

  8. The three-hit concept of vulnerability and resilience: toward understanding adaptation to early-life adversity outcome.

    PubMed

    Daskalakis, Nikolaos P; Bagot, Rosemary C; Parker, Karen J; Vinkers, Christiaan H; de Kloet, E R

    2013-09-01

    Stressful experiences during early-life can modulate the genetic programming of specific brain circuits underlying emotional and cognitive aspects of behavioral adaptation to stressful experiences later in life. Although this programming effect exerted by experience-related factors is an important determinant of mental health, its outcome depends on cognitive inputs and hence the valence an individual assigns to a given environmental context. From this perspective we will highlight, with studies in rodents, non-human primates and humans, the three-hit concept of vulnerability and resilience to stress-related mental disorders, which is based on gene-environment interactions during critical phases of perinatal and juvenile brain development. The three-hit (i.e., hit-1: genetic predisposition, hit-2: early-life environment, and hit-3: later-life environment) concept accommodates the cumulative stress hypothesis stating that in a given context vulnerability is enhanced when failure to cope with adversity accumulates. Alternatively, the concept also points to the individual's predictive adaptive capacity, which underlies the stress inoculation and match/mismatch hypotheses. The latter hypotheses propose that the experience of relatively mild early-life adversity prepares for the future and promotes resilience to similar challenges in later-life; when a mismatch occurs between early and later-life experience, coping is compromised and vulnerability is enhanced. The three-hit concept is fundamental for understanding how individuals can either be prepared for coping with life to come and remain resilient or are unable to do so and succumb to a stress-related mental disorder, under seemingly identical circumstances.

  9. Detached Eddy Simulation of the UH-60 Rotor Wake Using Adaptive Mesh Refinement

    NASA Technical Reports Server (NTRS)

    Chaderjian, Neal M.; Ahmad, Jasim U.

    2012-01-01

    Time-dependent Navier-Stokes flow simulations have been carried out for a UH-60 rotor with simplified hub in forward flight and hover flight conditions. Flexible rotor blades and flight trim conditions are modeled and established by loosely coupling the OVERFLOW Computational Fluid Dynamics (CFD) code with the CAMRAD II helicopter comprehensive code. High order spatial differences, Adaptive Mesh Refinement (AMR), and Detached Eddy Simulation (DES) are used to obtain highly resolved vortex wakes, where the largest turbulent structures are captured. Special attention is directed towards ensuring the dual time accuracy is within the asymptotic range, and verifying the loose coupling convergence process using AMR. The AMR/DES simulation produced vortical worms for forward flight and hover conditions, similar to previous results obtained for the TRAM rotor in hover. AMR proved to be an efficient means to capture a rotor wake without a priori knowledge of the wake shape.

  10. Effectively explore metastable states of proteins by adaptive nonequilibrium driving simulations

    NASA Astrophysics Data System (ADS)

    Wan, Biao; Xu, Shun; Zhou, Xin

    2017-03-01

    Nonequilibrium drivings applied in molecular dynamics (MD) simulations can efficiently extend the visiting range of protein conformations, but might compel systems to go far away from equilibrium and thus mainly explore irrelevant conformations. Here we propose a general method, called adaptive nonequilibrium simulation (ANES), to automatically adjust the external driving on the fly, based on the feedback of the short-time average response of system. Thus, the ANES approximately keeps the local equilibrium but efficiently accelerates the global motion. We illustrate the capability of the ANES in highly efficiently exploring metastable conformations in the deca-alanine peptide and find that the 0.2 -μ s ANES approximately captures the important states and folding and unfolding pathways in the HP35 solution by comparing with the result of the recent 398 -μ s equilibrium MD simulation on Anton [S. Piana et al., Proc. Natl. Acad. Sci. USA 109, 17845 (2012), 10.1073/pnas.1201811109].

  11. Spectral solver for multi-scale plasma physics simulations with dynamically adaptive number of moments

    SciTech Connect

    Vencels, Juris; Delzanno, Gian Luca; Johnson, Alec; Peng, Ivy Bo; Laure, Erwin; Markidis, Stefano

    2015-06-01

    A spectral method for kinetic plasma simulations based on the expansion of the velocity distribution function in a variable number of Hermite polynomials is presented. The method is based on a set of non-linear equations that is solved to determine the coefficients of the Hermite expansion satisfying the Vlasov and Poisson equations. In this paper, we first show that this technique combines the fluid and kinetic approaches into one framework. Second, we present an adaptive strategy to increase and decrease the number of Hermite functions dynamically during the simulation. The technique is applied to the Landau damping and two-stream instability test problems. Performance results show 21% and 47% saving of total simulation time in the Landau and two-stream instability test cases, respectively.

  12. Spectral solver for multi-scale plasma physics simulations with dynamically adaptive number of moments

    DOE PAGES

    Vencels, Juris; Delzanno, Gian Luca; Johnson, Alec; ...

    2015-06-01

    A spectral method for kinetic plasma simulations based on the expansion of the velocity distribution function in a variable number of Hermite polynomials is presented. The method is based on a set of non-linear equations that is solved to determine the coefficients of the Hermite expansion satisfying the Vlasov and Poisson equations. In this paper, we first show that this technique combines the fluid and kinetic approaches into one framework. Second, we present an adaptive strategy to increase and decrease the number of Hermite functions dynamically during the simulation. The technique is applied to the Landau damping and two-stream instabilitymore » test problems. Performance results show 21% and 47% saving of total simulation time in the Landau and two-stream instability test cases, respectively.« less

  13. Soapy: an adaptive optics simulation written purely in Python for rapid concept development

    NASA Astrophysics Data System (ADS)

    Reeves, Andrew

    2016-07-01

    Soapy is a newly developed Adaptive Optics (AO) simulation which aims be a flexible and fast to use tool-kit for many applications in the field of AO. It is written purely in the Python language, adding to and taking advantage of the already rich ecosystem of scientific libraries and programs. The simulation has been designed to be extremely modular, such that each component can be used stand-alone for projects which do not require a full end-to-end simulation. Ease of use, modularity and code clarity have been prioritised at the expense of computational performance. Though this means the code is not yet suitable for large studies of Extremely Large Telescope AO systems, it is well suited to education, exploration of new AO concepts and investigations of current generation telescopes.

  14. Reactively and Anticipatory Behaving Agents for Artificial Life Simulations

    NASA Astrophysics Data System (ADS)

    Kohout, Karel; Nahodil, Pavel

    2010-11-01

    Reactive behavior is still considered and the exact opposite for the anticipatory one. Despite the advances on the field of anticipation there are little thoughts on relation with the reactive behavior, the similarities and where the boundary is. In this article we will present our viewpoint and we will try to show that reactive and anticipatory behavior can be combined. This is the basic ground of our unified theory for anticipatory behavior architecture. We still miss such compact theory, which would integrate multiple aspects of anticipation. My multi-level anticipatory behavior approach is based on the current understanding of anticipation from both the artificial intelligence and biology point of view. As part of the explanation we will also elaborate on the topic of weak and strong artificial life. Anticipation is not matter of a single mechanism in a living organism. It was noted already that it happens on many different levels even in the very simple creatures. What we consider to be important for our work and what is our original though is that it happens even without voluntary control. We believe that this is novelty though for the anticipation theory. Naturally research of anticipation was in the beginning of this decade focused on the anticipatory principles bringing advances on the field itself. This allowed us to build on those, look at them from higher perspective, and use not one but multiple levels of anticipation in a creature design. This presents second original though and that is composition of the agent architecture that has anticipation built in almost every function. In this article we will focus only on first two levels within the 8-factor anticipation framework. We will introduce them as defined categories of anticipation and describe them from theory and implementation algorithm point of view. We will also present an experiment conducted, however this experiment serves more as explanatory example. These first two levels may seem trivial

  15. Adaptive resolution simulation of an atomistic DNA molecule in MARTINI salt solution

    NASA Astrophysics Data System (ADS)

    Zavadlav, J.; Podgornik, R.; Melo, M. N.; Marrink, S. J.; Praprotnik, M.

    2016-10-01

    We present a dual-resolution model of a deoxyribonucleic acid (DNA) molecule in a bathing solution, where we concurrently couple atomistic bundled water and ions with the coarse-grained MARTINI model of the solvent. We use our fine-grained salt solution model as a solvent in the inner shell surrounding the DNA molecule, whereas the solvent in the outer shell is modeled by the coarse-grained model. The solvent entities can exchange between the two domains and adapt their resolution accordingly. We critically asses the performance of our multiscale model in adaptive resolution simulations of an infinitely long DNA molecule, focusing on the structural characteristics of the solvent around DNA. Our analysis shows that the adaptive resolution scheme does not produce any noticeable artifacts in comparison to a reference system simulated in full detail. The effect of using a bundled-SPC model, required for multiscaling, compared to the standard free SPC model is also evaluated. Our multiscale approach opens the way for large scale applications of DNA and other biomolecules which require a large solvent reservoir to avoid boundary effects.

  16. Adaptive vision-based control of a motor-toggle mechanism: Simulations and experiments

    NASA Astrophysics Data System (ADS)

    Chuang, Chin-Wen; Huang, Ming-Shyan; Chen, Kun-Yung; Fung, Rong-Fong

    2008-05-01

    The dynamic motion of an adaptive visual servoing feedback-controlled punching machine, which is made up by a toggle mechanism driven by a permanent magnet (PM) synchronous servomotor, is studied numerically and experimentally. First, Hamilton's principle, Lagrange multiplier, geometric constraints and partitioning method are employed to derive its dynamic equations for numerical simulations. To satisfy the demand of the machine performance, adaptive controller by using stability analysis with inertia-related Lyapunov function is designed to control the slider responses. Different from the previous studies, the vision servo system of a non-contact measurement of a charge-coupled device (CCD) camera is employed to measure the shape patterns as output states instead of using the expensive linear scale or encoder of the motor-mechanism system. Finally, the stable and robust control performances of an adaptive controller by the Lyapunov stable theory for a motor-toggle mechanism with external disturbances are proposed. A combination of the visual servoing measurement system and the motion control system are established experimentally for the motor-toggle mechanism system. From the agreements between numerical simulations and experimental results, it is demonstrated that the proposed controller, by use of machine vision, is robust to external disturbances for a punching machine system.

  17. Accelerating Markov chain Monte Carlo simulation by differential evolution with self-adaptive randomized subspace sampling

    SciTech Connect

    Vrugt, Jasper A; Hyman, James M; Robinson, Bruce A; Higdon, Dave; Ter Braak, Cajo J F; Diks, Cees G H

    2008-01-01

    Markov chain Monte Carlo (MCMC) methods have found widespread use in many fields of study to estimate the average properties of complex systems, and for posterior inference in a Bayesian framework. Existing theory and experiments prove convergence of well constructed MCMC schemes to the appropriate limiting distribution under a variety of different conditions. In practice, however this convergence is often observed to be disturbingly slow. This is frequently caused by an inappropriate selection of the proposal distribution used to generate trial moves in the Markov Chain. Here we show that significant improvements to the efficiency of MCMC simulation can be made by using a self-adaptive Differential Evolution learning strategy within a population-based evolutionary framework. This scheme, entitled DiffeRential Evolution Adaptive Metropolis or DREAM, runs multiple different chains simultaneously for global exploration, and automatically tunes the scale and orientation of the proposal distribution in randomized subspaces during the search. Ergodicity of the algorithm is proved, and various examples involving nonlinearity, high-dimensionality, and multimodality show that DREAM is generally superior to other adaptive MCMC sampling approaches. The DREAM scheme significantly enhances the applicability of MCMC simulation to complex, multi-modal search problems.

  18. Transient analysis of distribution class Adaptive Var Compensators: Simulation and field test results

    SciTech Connect

    Kagalwala, R.A.; Venkata, S.S.; El-Sharkawi, M.A.; Butler, N.G.; Van Leuven, A.; Rodriguez, A.P.; Kerszenbaum, I.; Smith, D.

    1995-04-01

    Simulation studies are performed to analyze the transient behavior of the Adaptive Var Compensator (AVC), a power electronic device installed at the distribution level, during its design, installation and field testing stages. The simulation model includes detailed models for power apparatus, power semiconductor devices and low signal level electronics. Hence, by using this model, a wide range of simulation studies which contribute towards the development of the AVC and its effectiveness in the field can all be performed on the same platform. A new power electronics simulator called SABER has proven to be very effective for this study because of its model-independent structure and extensive library that covers various disciplines of engineering. The simulation studies are aimed at gaining a better understanding of the interaction between the AVC and the distribution system. They cover a range of phenomena such as switching transients due to mechanical capacitor bank closing, fast transients due to reverse recovery of the power diodes of the AVC, power system harmonics and voltage flicker problem. This paper also briefly describes the criteria for selection of the simulation tool and the models developed.

  19. Analysis of Adaptive Mesh Refinement for IMEX Discontinuous Galerkin Solutions of the Compressible Euler Equations with Application to Atmospheric Simulations

    DTIC Science & Technology

    2013-01-01

    Analysis of Adaptive Mesh Refinement for IMEX Discontinuous Galerkin Solutions of the Compressible Euler Equations with Application to Atmospheric...order discontinuous Galerkin method on quadrilateral grids with non-conforming elements. We perform a detailed analysis of the cost of AMR by comparing...adaptive mesh refinement, discontinuous Galerkin method, non-conforming mesh, IMEX, compressible Euler equations, atmospheric simulations 1. Introduction

  20. Adaptive wavelet simulation of global ocean dynamics using a new Brinkman volume penalization

    NASA Astrophysics Data System (ADS)

    Kevlahan, N. K.-R.; Dubos, T.; Aechtner, M.

    2015-12-01

    In order to easily enforce solid-wall boundary conditions in the presence of complex coastlines, we propose a new mass and energy conserving Brinkman penalization for the rotating shallow water equations. This penalization does not lead to higher wave speeds in the solid region. The error estimates for the penalization are derived analytically and verified numerically for linearized one-dimensional equations. The penalization is implemented in a conservative dynamically adaptive wavelet method for the rotating shallow water equations on the sphere with bathymetry and coastline data from NOAA's ETOPO1 database. This code could form the dynamical core for a future global ocean model. The potential of the dynamically adaptive ocean model is illustrated by using it to simulate the 2004 Indonesian tsunami and wind-driven gyres.

  1. Performance simulation of the ERIS pyramid wavefront sensor module in the VLT adaptive optics facility

    NASA Astrophysics Data System (ADS)

    Quirós-Pacheco, Fernando; Agapito, Guido; Riccardi, Armando; Esposito, Simone; Le Louarn, Miska; Marchetti, Enrico

    2012-07-01

    This paper presents the performance analysis based on numerical simulations of the Pyramid Wavefront sensor Module (PWM) to be included in ERIS, the new Adaptive Optics (AO) instrument for the Adaptive Optics Facility (AOF). We have analyzed the performance of the PWM working either in a low-order or in a high-order wavefront sensing mode of operation. We show that the PWM in the high-order sensing mode can provide SR > 90% in K band using bright guide stars under median seeing conditions (0.85 arcsec seeing and 15 m/s of wind speed). In the low-order sensing mode, the PWM can sense and correct Tip-Tilt (and if requested also Focus mode) with the precision required to assist the LGS observations to get an SR > 60% and > 20% in K band, using up to a ~16.5 and ~19.5 R-magnitude guide star, respectively.

  2. Advantages and challenges in coupling an ideal gas to atomistic models in adaptive resolution simulations

    NASA Astrophysics Data System (ADS)

    Kreis, K.; Fogarty, A. C.; Kremer, K.; Potestio, R.

    2015-09-01

    In adaptive resolution simulations, molecular fluids are modeled employing different levels of resolution in different subregions of the system. When traveling from one region to the other, particles change their resolution on the fly. One of the main advantages of such approaches is the computational efficiency gained in the coarse-grained region. In this respect the best coarse-grained system to employ in the low resolution region would be the ideal gas, making intermolecular force calculations in the coarse-grained subdomain redundant. In this case, however, a smooth coupling is challenging due to the high energetic imbalance between typical liquids and a system of non-interacting particles. In the present work, we investigate this approach, using as a test case the most biologically relevant fluid, water. We demonstrate that a successful coupling of water to the ideal gas can be achieved with current adaptive resolution methods, and discuss the issues that remain to be addressed.

  3. Advanced adaptive computational methods for Navier-Stokes simulations in rotorcraft aerodynamics

    NASA Technical Reports Server (NTRS)

    Stowers, S. T.; Bass, J. M.; Oden, J. T.

    1993-01-01

    A phase 2 research and development effort was conducted in area transonic, compressible, inviscid flows with an ultimate goal of numerically modeling complex flows inherent in advanced helicopter blade designs. The algorithms and methodologies therefore are classified as adaptive methods, which are error estimation techniques for approximating the local numerical error, and automatically refine or unrefine the mesh so as to deliver a given level of accuracy. The result is a scheme which attempts to produce the best possible results with the least number of grid points, degrees of freedom, and operations. These types of schemes automatically locate and resolve shocks, shear layers, and other flow details to an accuracy level specified by the user of the code. The phase 1 work involved a feasibility study of h-adaptive methods for steady viscous flows, with emphasis on accurate simulation of vortex initiation, migration, and interaction. Phase 2 effort focused on extending these algorithms and methodologies to a three-dimensional topology.

  4. Long-time simulations of the Kelvin-Helmholtz instability using an adaptive vortex method.

    PubMed

    Sohn, Sung-Ik; Yoon, Daeki; Hwang, Woonjae

    2010-10-01

    The nonlinear evolution of an interface subject to a parallel shear flow is studied by the vortex sheet model. We perform long-time computations for the vortex sheet in density-stratified fluids by using the point vortex method and investigate late-time dynamics of the Kelvin-Helmholtz instability. We apply an adaptive point insertion procedure and a high-order shock-capturing scheme to the vortex method to handle the nonuniform distribution of point vortices and enhance the resolution. Our adaptive vortex method successfully simulates chaotically distorted interfaces of the Kelvin-Helmholtz instability with fine resolutions. The numerical results show that the Kelvin-Helmholtz instability evolves a secondary instability at a late time, distorting the internal rollup, and eventually develops to a disordered structure.

  5. Experimental and simulation study results of an Adaptive Video Guidance System /AVGS/

    NASA Technical Reports Server (NTRS)

    Schappell, R. T.; Knickerbocker, R. L.

    1975-01-01

    Studies relating to stellar-body exploration programs have pointed out the need for an adaptive guidance scheme capable of providing automatic real-time guidance and site selection capability. For the case of a planetary lander, without such guidance, targeting is limited to what are believed to be generally benign areas in order to ensure a reasonable landing-success probability. Typically, the Mars Viking Lander will be jeopardized by obstacles exceeding 22 centimers in diameter. The benefits of on-board navigation and real-time selection of a landing site and obstacle avoidance have been demonstrated by the Apollo lunar landings, in which man performed the surface sensing and steering functions. Therefore, an Adaptive Video Guidance System (AVGS) has been developed, bread-boarded, and flown on a six-degree-of-freedom simulator.

  6. An adaptive tau-leaping method for stochastic simulations of reaction-diffusion systems

    NASA Astrophysics Data System (ADS)

    Padgett, Jill M. A.; Ilie, Silvana

    2016-03-01

    Stochastic modelling is critical for studying many biochemical processes in a cell, in particular when some reacting species have low population numbers. For many such cellular processes the spatial distribution of the molecular species plays a key role. The evolution of spatially heterogeneous biochemical systems with some species in low amounts is accurately described by the mesoscopic model of the Reaction-Diffusion Master Equation. The Inhomogeneous Stochastic Simulation Algorithm provides an exact strategy to numerically solve this model, but it is computationally very expensive on realistic applications. We propose a novel adaptive time-stepping scheme for the tau-leaping method for approximating the solution of the Reaction-Diffusion Master Equation. This technique combines effective strategies for variable time-stepping with path preservation to reduce the computational cost, while maintaining the desired accuracy. The numerical tests on various examples arising in applications show the improved efficiency achieved by the new adaptive method.

  7. Adaptations to Hydrothermal Vent Life in Kiwa tyleri, a New Species of Yeti Crab from the East Scotia Ridge, Antarctica.

    PubMed

    Thatje, Sven; Marsh, Leigh; Roterman, Christopher Nicolai; Mavrogordato, Mark N; Linse, Katrin

    2015-01-01

    Hydrothermal vents in the Southern Ocean are the physiologically most isolated chemosynthetic environments known. Here, we describe Kiwa tyleri sp. nov., the first species of yeti crab known from the Southern Ocean. Kiwa tyleri belongs to the family Kiwaidae and is the visually dominant macrofauna of two known vent sites situated on the northern and southern segments of the East Scotia Ridge (ESR). The species is known to depend on primary productivity by chemosynthetic bacteria and resides at the warm-eurythermal vent environment for most of its life; its short-range distribution away from vents (few metres) is physiologically constrained by the stable, cold waters of the surrounding Southern Ocean. Kiwa tylerihas been shown to present differential life history adaptations in response to this contrasting thermal environment. Morphological adaptations specific to life in warm-eurythermal waters, as found on - or in close proximity of - vent chimneys, are discussed in comparison with adaptations seen in the other two known members of the family (K. hirsuta, K. puravida), which show a preference for low temperature chemosynthetic environments.

  8. Social Daydreaming and Adjustment: An Experience-Sampling Study of Socio-Emotional Adaptation During a Life Transition

    PubMed Central

    Poerio, Giulia L.; Totterdell, Peter; Emerson, Lisa-Marie; Miles, Eleanor

    2016-01-01

    Estimates suggest that up to half of waking life is spent daydreaming; that is, engaged in thought that is independent of, and unrelated to, one’s current task. Emerging research indicates that daydreams are predominately social suggesting that daydreams may serve socio-emotional functions. Here we explore the functional role of social daydreaming for socio-emotional adjustment during an important and stressful life transition (the transition to university) using experience-sampling with 103 participants over 28 days. Over time, social daydreams increased in their positive characteristics and positive emotional outcomes; specifically, participants reported that their daydreams made them feel more socially connected and less lonely, and that the content of their daydreams became less fanciful and involved higher quality relationships. These characteristics then predicted less loneliness at the end of the study, which, in turn was associated with greater social adaptation to university. Feelings of connection resulting from social daydreams were also associated with less emotional inertia in participants who reported being less socially adapted to university. Findings indicate that social daydreaming is functional for promoting socio-emotional adjustment to an important life event. We highlight the need to consider the social content of stimulus-independent cognitions, their characteristics, and patterns of change, to specify how social thoughts enable socio-emotional adaptation. PMID:26834685

  9. Zooming in on Life Events: Is Hedonic Adaptation Sensitive to the Temporal Distance from the Event?

    ERIC Educational Resources Information Center

    Uglanova, Ekaterina A.; Staudinger, Ursula M.

    2013-01-01

    This paper analyzed the effect of major positive and negative life events (marriage, divorce, birth of child, widowhood, and unemployment) on life satisfaction. For the first time, this study estimated the effects of life events not with a precision of 12 months but of 3 months. Specifically, two questions were addressed: (1) Does the precision of…

  10. Binocular adaptive optics visual simulator: understanding the impact of aberrations on actual vision

    NASA Astrophysics Data System (ADS)

    Fernández, Enrique J.; Prieto, Pedro M.; Artal, Pablo

    2010-02-01

    A novel adaptive optics system is presented for the study of vision. The apparatus is capable for binocular operation. The binocular adaptive optics visual simulator permits measuring and manipulating ocular aberrations of the two eyes simultaneously. Aberrations can be corrected, or modified, while the subject performs visual testing under binocular vision. One of the most remarkable features of the apparatus consists on the use of a single correcting device, and a single wavefront sensor (Hartmann-Shack). Both the operation and the total cost of the instrument largely benefit from this attribute. The correcting device is a liquid-crystal-on-silicon (LCOS) spatial light modulator. The basic performance of the visual simulator consists in the simultaneous projection of the two eyes' pupils onto both the corrector and sensor. Examples of the potential of the apparatus for the study of the impact of the aberrations under binocular vision are presented. Measurements of contrast sensitivity with modified combinations of spherical aberration through focus are shown. Special attention was paid on the simulation of monovision, where one eye is corrected for far vision while the other is focused at near distance. The results suggest complex binocular interactions. The apparatus can be dedicated to the better understanding of the vision mechanism, which might have an important impact in developing new protocols and treatments for presbyopia. The technique and the instrument might contribute to search optimized ophthalmic corrections.

  11. Improve earthquake hypocenter using adaptive simulated annealing inversion in regional tectonic, volcano tectonic, and geothermal observation

    SciTech Connect

    Ry, Rexha Verdhora; Nugraha, Andri Dian

    2015-04-24

    Observation of earthquakes is routinely used widely in tectonic activity observation, and also in local scale such as volcano tectonic and geothermal activity observation. It is necessary for determining the location of precise hypocenter which the process involves finding a hypocenter location that has minimum error between the observed and the calculated travel times. When solving this nonlinear inverse problem, simulated annealing inversion method can be applied to such global optimization problems, which the convergence of its solution is independent of the initial model. In this study, we developed own program codeby applying adaptive simulated annealing inversion in Matlab environment. We applied this method to determine earthquake hypocenter using several data cases which are regional tectonic, volcano tectonic, and geothermal field. The travel times were calculated using ray tracing shooting method. We then compared its results with the results using Geiger’s method to analyze its reliability. Our results show hypocenter location has smaller RMS error compared to the Geiger’s result that can be statistically associated with better solution. The hypocenter of earthquakes also well correlated with geological structure in the study area. Werecommend using adaptive simulated annealing inversion to relocate hypocenter location in purpose to get precise and accurate earthquake location.

  12. Aberration estimation from single point image in a simulated adaptive optics system.

    PubMed

    Grisan, Enrico; Frassetto, Fabio; Da Deppo, Vania; Naletto, Giampiero; Ruggeri, Alfredo

    2005-01-01

    Adaptive optics has been recently applied for the development of ophthalmic devices, with the main objective of obtaining higher resolution images for diagnostic purposes or ideally correcting high-order eye aberrations. The core of every adaptive optics systems is an optical device that is able to modify the wavefront shape of the light entering a system: once the shape of the incoming wavefront has been estimated, by means of this device it is possible to correct the aberrations introduced along the optical path. The aim of this paper is to demonstrate the feasibility, although in a simulated system, of estimating and correcting the wavefront shape simply by means of an iterative software analysis of a single point source image, thus avoiding expensive wavefront sensors or the burdensome computation of the PSF of the optical system. To test the proposed algorithm, a simple optical system has been simulated with a ray-tracing software and a program to estimate the Zernike coefficients of the simulated aberration from the analysis of the source image has been developed. Numerical indexes were used to evaluate the capability of the software of correctly estimating the Zernike coefficients. Even if only defocus, astigmatism and coma were considered, the very satisfactory results obtained confirm the soundness of this new approach and encourage further work in this direction, in order to develop a system able to estimate also spherical aberration, tilt and field curvature. An implementation of this aberration estimation in a real AO system is also currently in progress.

  13. Improve earthquake hypocenter using adaptive simulated annealing inversion in regional tectonic, volcano tectonic, and geothermal observation

    NASA Astrophysics Data System (ADS)

    Ry, Rexha Verdhora; Nugraha, Andri Dian

    2015-04-01

    Observation of earthquakes is routinely used widely in tectonic activity observation, and also in local scale such as volcano tectonic and geothermal activity observation. It is necessary for determining the location of precise hypocenter which the process involves finding a hypocenter location that has minimum error between the observed and the calculated travel times. When solving this nonlinear inverse problem, simulated annealing inversion method can be applied to such global optimization problems, which the convergence of its solution is independent of the initial model. In this study, we developed own program codeby applying adaptive simulated annealing inversion in Matlab environment. We applied this method to determine earthquake hypocenter using several data cases which are regional tectonic, volcano tectonic, and geothermal field. The travel times were calculated using ray tracing shooting method. We then compared its results with the results using Geiger's method to analyze its reliability. Our results show hypocenter location has smaller RMS error compared to the Geiger's result that can be statistically associated with better solution. The hypocenter of earthquakes also well correlated with geological structure in the study area. Werecommend using adaptive simulated annealing inversion to relocate hypocenter location in purpose to get precise and accurate earthquake location.

  14. Adaptive accelerated ReaxFF reactive dynamics with validation from simulating hydrogen combustion.

    PubMed

    Cheng, Tao; Jaramillo-Botero, Andrés; Goddard, William A; Sun, Huai

    2014-07-02

    We develop here the methodology for dramatically accelerating the ReaxFF reactive force field based reactive molecular dynamics (RMD) simulations through use of the bond boost concept (BB), which we validate here for describing hydrogen combustion. The bond order, undercoordination, and overcoordination concepts of ReaxFF ensure that the BB correctly adapts to the instantaneous configurations in the reactive system to automatically identify the reactions appropriate to receive the bond boost. We refer to this as adaptive Accelerated ReaxFF Reactive Dynamics or aARRDyn. To validate the aARRDyn methodology, we determined the detailed sequence of reactions for hydrogen combustion with and without the BB. We validate that the kinetics and reaction mechanisms (that is the detailed sequences of reactive intermediates and their subsequent transformation to others) for H2 oxidation obtained from aARRDyn agrees well with the brute force reactive molecular dynamics (BF-RMD) at 2498 K. Using aARRDyn, we then extend our simulations to the whole range of combustion temperatures from ignition (798 K) to flame temperature (2998K), and demonstrate that, over this full temperature range, the reaction rates predicted by aARRDyn agree well with the BF-RMD values, extrapolated to lower temperatures. For the aARRDyn simulation at 798 K we find that the time period for half the H2 to form H2O product is ∼538 s, whereas the computational cost was just 1289 ps, a speed increase of ∼0.42 trillion (10(12)) over BF-RMD. In carrying out these RMD simulations we found that the ReaxFF-COH2008 version of the ReaxFF force field was not accurate for such intermediates as H3O. Consequently we reoptimized the fit to a quantum mechanics (QM) level, leading to the ReaxFF-OH2014 force field that was used in the simulations.

  15. Direct numerical simulations of particle-laden density currents with adaptive, discontinuous finite elements

    NASA Astrophysics Data System (ADS)

    Parkinson, S. D.; Hill, J.; Piggott, M. D.; Allison, P. A.

    2014-09-01

    High-resolution direct numerical simulations (DNSs) are an important tool for the detailed analysis of turbidity current dynamics. Models that resolve the vertical structure and turbulence of the flow are typically based upon the Navier-Stokes equations. Two-dimensional simulations are known to produce unrealistic cohesive vortices that are not representative of the real three-dimensional physics. The effect of this phenomena is particularly apparent in the later stages of flow propagation. The ideal solution to this problem is to run the simulation in three dimensions but this is computationally expensive. This paper presents a novel finite-element (FE) DNS turbidity current model that has been built within Fluidity, an open source, general purpose, computational fluid dynamics code. The model is validated through re-creation of a lock release density current at a Grashof number of 5 × 106 in two and three dimensions. Validation of the model considers the flow energy budget, sedimentation rate, head speed, wall normal velocity profiles and the final deposit. Conservation of energy in particular is found to be a good metric for measuring model performance in capturing the range of dynamics on a range of meshes. FE models scale well over many thousands of processors and do not impose restrictions on domain shape, but they are computationally expensive. The use of adaptive mesh optimisation is shown to reduce the required element count by approximately two orders of magnitude in comparison with fixed, uniform mesh simulations. This leads to a substantial reduction in computational cost. The computational savings and flexibility afforded by adaptivity along with the flexibility of FE methods make this model well suited to simulating turbidity currents in complex domains.

  16. All about Plant Adaptation. Plant Life for Children[TM]. Schlessinger Science Library. [Videotape].

    ERIC Educational Resources Information Center

    2000

    Plants can survive in even the harshest of environments, from the freezing Arctic to the arid desert. In All About Plant Adaptation, join young plant lovers as they uncover some of the amazing ways that plants have adapted over millions of years enabling them to survive almost anywhere on Earth. Discover how some plants living in cold, arctic…

  17. Adaptive Change in Self-Concept and Well-Being during Conjugal Loss in Later Life

    ERIC Educational Resources Information Center

    Montpetit, Mignon A.; Bergeman, C. S.; Bisconti, Toni L.; Rausch, Joseph R.

    2006-01-01

    The present study examines the association between the self-concept and adaptation to conjugal loss; the primary aim was to explore whether those individuals high in self-esteem, environmental mastery, and optimism have more adaptive resources with which to ameliorate the detrimental sequelae of bereavement. Analyses were conducted on data…

  18. Cyberwar XXI: quantifying the unquantifiable: adaptive AI for next-generation conflict simulations

    NASA Astrophysics Data System (ADS)

    Miranda, Joseph; von Kleinsmid, Peter; Zalewski, Tony

    2004-08-01

    The era of the "Revolution in Military Affairs," "4th Generation Warfare" and "Asymmetric War" requires novel approaches to modeling warfare at the operational and strategic level of modern conflict. For example, "What if, in response to our planned actions, the adversary reacts in such-and-such a manner? What will our response be? What are the possible unintended consequences?" Next generation conflict simulation tools are required to help create and test novel courses of action (COA's) in support of real-world operations. Conflict simulations allow non-lethal and cost-effective exploration of the "what-if" of COA development. The challenge has been to develop an automated decision-support software tool which allows competing COA"s to be compared in simulated dynamic environments. Principal Investigator Joseph Miranda's research is based on modeling an integrated military, economic, social, infrastructure and information (PMESII) environment. The main effort was to develop an adaptive AI engine which models agents operating within an operational-strategic conflict environment. This was implemented in Cyberwar XXI - a simulation which models COA selection in a PMESII environment. Within this framework, agents simulate decision-making processes and provide predictive capability of the potential behavior of Command Entities. The 2003 Iraq is the first scenario ready for V&V testing.

  19. Adaptive resolution simulation of a biomolecule and its hydration shell: Structural and dynamical properties

    SciTech Connect

    Fogarty, Aoife C. Potestio, Raffaello Kremer, Kurt

    2015-05-21

    A fully atomistic modelling of many biophysical and biochemical processes at biologically relevant length- and time scales is beyond our reach with current computational resources, and one approach to overcome this difficulty is the use of multiscale simulation techniques. In such simulations, when system properties necessitate a boundary between resolutions that falls within the solvent region, one can use an approach such as the Adaptive Resolution Scheme (AdResS), in which solvent particles change their resolution on the fly during the simulation. Here, we apply the existing AdResS methodology to biomolecular systems, simulating a fully atomistic protein with an atomistic hydration shell, solvated in a coarse-grained particle reservoir and heat bath. Using as a test case an aqueous solution of the regulatory protein ubiquitin, we first confirm the validity of the AdResS approach for such systems, via an examination of protein and solvent structural and dynamical properties. We then demonstrate how, in addition to providing a computational speedup, such a multiscale AdResS approach can yield otherwise inaccessible physical insights into biomolecular function. We use our methodology to show that protein structure and dynamics can still be correctly modelled using only a few shells of atomistic water molecules. We also discuss aspects of the AdResS methodology peculiar to biomolecular simulations.

  20. Integrating Problem-Based Learning and Simulation: Effects on Student Motivation and Life Skills.

    PubMed

    Roh, Young Sook; Kim, Sang Suk

    2015-07-01

    Previous research has suggested that a teaching strategy integrating problem-based learning and simulation may be superior to traditional lecture. The purpose of this study was to assess learner motivation and life skills before and after taking a course involving problem-based learning and simulation. The design used repeated measures with a convenience sample of 83 second-year nursing students who completed the integrated course. Data from a self-administered questionnaire measuring learner motivation and life skills were collected at pretest, post-problem-based learning, and post-simulation time points. Repeated-measures analysis of variance determined that the mean scores for total learner motivation (F=6.62, P=.003), communication (F=8.27, P<.001), problem solving (F=6.91, P=.001), and self-directed learning (F=4.45, P=.016) differed significantly between time points. Post hoc tests using the Bonferroni correction revealed that total learner motivation and total life skills significantly increased both from pretest to postsimulation and from post-problem-based learning test to postsimulation test. Subscales of learner motivation and life skills, intrinsic goal orientation, self-efficacy for learning and performance, problem-solving skills, and self-directed learning skills significantly increased both from pretest to postsimulation test and from post-problem-based learning test to post-simulation test. The results demonstrate that an integrating problem-based learning and simulation course elicits significant improvement in learner motivation and life skills. Simulation plus problem-based learning is more effective than problem-based learning alone at increasing intrinsic goal orientation, task value, self-efficacy for learning and performance, problem solving, and self-directed learning.

  1. Testing Refinement Criteria in Adaptive Discontinuous Galerkin Simulations of Dry Atmospheric Convection

    DTIC Science & Technology

    2011-12-22

    Testing refinement criteria in adaptive Discontinuous Galerkin simulations of dry atmospheric convection Andreas Müllera,∗, Jörn Behrensb, Francis X...mainz.de (Andreas Müller), joern.behrens@zmaw.de (Jörn Behrens), fxgirald@nps.edu ( Francis X. Giraldo), vwirth@uni-mainz.de (Volkmar Wirth) Preprint...formulation and accuracy, Mon. Weather Rev. 120 (1992) 1675–1706. [3] D. P. Bacon , N. N. Ahmad, Z. Boybeyi, T. J. Dunn, M. S. Hall, P. C. S. Lee, R. A

  2. Comparison between Adaptive and Uniform Discontinuous Galerkin Simulations in Dry 2D Bubble Experiments

    DTIC Science & Technology

    2012-11-08

    Comparison between adaptive and uniform discontinuous Galerkin simulations in dry 2D bubble experiments Andreas Müllera,∗, Jörn Behrensb, Francis X...joern.behrens@zmaw.de (Jörn Behrens), fxgirald@nps.edu ( Francis X. Giraldo), vwirth@uni-mainz.de (Volkmar Wirth) Accepted by Journal of Computational...Mon. Weather Rev. 120 (1992) 1675–1706. [3] D. P. Bacon , N. N. Ahmad, Z. Boybeyi, T. J. Dunn, M. S. Hall, P. C. S. Lee, R. A. Sarma, M. D. Turner, K. T

  3. Simulation of the M13 life cycle I: Assembly of a genetically-structured deterministic chemical kinetic simulation.

    PubMed

    Smeal, Steven W; Schmitt, Margaret A; Pereira, Ronnie Rodrigues; Prasad, Ashok; Fisk, John D

    2017-01-01

    To expand the quantitative, systems level understanding and foster the expansion of the biotechnological applications of the filamentous bacteriophage M13, we have unified the accumulated quantitative information on M13 biology into a genetically-structured, experimentally-based computational simulation of the entire phage life cycle. The deterministic chemical kinetic simulation explicitly includes the molecular details of DNA replication, mRNA transcription, protein translation and particle assembly, as well as the competing protein-protein and protein-nucleic acid interactions that control the timing and extent of phage production. The simulation reproduces the holistic behavior of M13, closely matching experimentally reported values of the intracellular levels of phage species and the timing of events in the M13 life cycle. The computational model provides a quantitative description of phage biology, highlights gaps in the present understanding of M13, and offers a framework for exploring alternative mechanisms of regulation in the context of the complete M13 life cycle.

  4. The Building: An Adaptation of Francis Debyser's Writing Project. A Global Simulation To Teach Language and Culture.

    ERIC Educational Resources Information Center

    Magnin, Michele Claude

    A "global simulation" is a class activity allowing students to encounter situations that include love, life, and death in a simulated environment. This paper describes several possible simulations. Each one can be integrated into a variety of intermediate- to advanced-level curricula such as a conversation class, a culture and civilization class,…

  5. Spatially adaptive radiation-hydrodynamical simulations of galaxy formation during cosmological reionization

    NASA Astrophysics Data System (ADS)

    Pawlik, Andreas H.; Schaye, Joop; Dalla Vecchia, Claudio

    2015-08-01

    We present a suite of cosmological radiation-hydrodynamical simulations of the assembly of galaxies driving the reionization of the intergalactic medium (IGM) at z ≳ 6. The simulations account for the hydrodynamical feedback from photoionization heating and the explosion of massive stars as supernovae (SNe). Our reference simulation, which was carried out in a box of size 25 h-1 comovingMpc using 2 × 5123 particles, produces a reasonable reionization history and matches the observed UV luminosity function of galaxies. Simulations with different box sizes and resolutions are used to investigate numerical convergence, and simulations in which either SNe or photoionization heating or both are turned off, are used to investigate the role of feedback from star formation. Ionizing radiation is treated using accurate radiative transfer at the high spatially adaptive resolution at which the hydrodynamics is carried out. SN feedback strongly reduces the star formation rates (SFRs) over nearly the full mass range of simulated galaxies and is required to yield SFRs in agreement with observations. Photoheating helps to suppress star formation in low-mass galaxies, but its impact on the cosmic SFR is small. Because the effect of photoheating is masked by the strong SN feedback, it does not imprint a signature on the UV galaxy luminosity function, although we note that our resolution is insufficient to model star-forming minihaloes cooling through molecular hydrogen transitions. Photoheating does provide a strong positive feedback on reionization because it smooths density fluctuations in the IGM, which lowers the IGM recombination rate substantially. Our simulations demonstrate a tight non-linear coupling of galaxy formation and reionization, motivating the need for the accurate and simultaneous inclusion of photoheating and SN feedback in models of the early Universe.

  6. The evolution of an annual life cycle in killifish: adaptation to ephemeral aquatic environments through embryonic diapause.

    PubMed

    Furness, Andrew I

    2016-08-01

    An annual life cycle is characterized by growth, maturity, and reproduction condensed into a single, short season favourable to development, with production of embryos (seeds, cysts, or eggs) capable of surviving harsh conditions which juveniles or adults cannot tolerate. More typically associated with plants in desert environments, or temperate-zone insects exposed to freezing winters, the evolution of an annual life cycle in vertebrates is fairly novel. Killifish, small sexually dimorphic fishes in the Order Cyprinodontiformes, have adapted to seasonally ephemeral water bodies across much of Africa and South America through the independent evolution of an annual life history. These annual killifish produce hardy desiccation-resistant eggs that undergo diapause (developmental arrest) and remain buried in the soil for long periods when fish have perished due to the drying of their habitat. Killifish are found in aquatic habitats that span a continuum from permanent and stable to seasonal and variable, thus providing a useful system in which to piece together the evolutionary history of this life cycle using natural comparative variation. I first review adaptations for life in ephemeral aquatic environments in killifish, with particular emphasis on the evolution of embryonic diapause. I then bring together available evidence from a variety of approaches and provide a scenario for how this annual life cycle evolved. There are a number of features within Aplocheiloidei killifish including their inhabitation of marginal or edge aquatic habitat, their small size and rapid attainment of maturity, and egg properties that make them particularly well suited to the colonization of ephemeral waters.

  7. Life Span as the Measure of Performance and Learning in a Business Gaming Simulation

    ERIC Educational Resources Information Center

    Thavikulwat, Precha

    2012-01-01

    This study applies the learning curve method of measuring learning to participants of a computer-assisted business gaming simulation that includes a multiple-life-cycle feature. The study involved 249 participants. It verified the workability of the feature and estimated the participants' rate of learning at 17.4% for every doubling of experience.…

  8. The Effects of Poverty Simulation, an Experiential Learning Modality, on Students' Understanding of Life in Poverty

    ERIC Educational Resources Information Center

    Vandsburger, Etty; Duncan-Daston, Rana; Akerson, Emily; Dillon, Tom

    2010-01-01

    This research examines the impact of the Poverty Simulation Project, an experiential learning modality, on students' understanding of life in poverty. A total of 101 students representing 5 undergraduate majors in the College of Health and Human Services completed measures of critical thinking, understanding of others, and the active learning…

  9. The fuel cell model of abiogenesis: a new approach to origin-of-life simulations.

    PubMed

    Barge, Laura M; Kee, Terence P; Doloboff, Ivria J; Hampton, Joshua M P; Ismail, Mohammed; Pourkashanian, Mohamed; Zeytounian, John; Baum, Marc M; Moss, John A; Lin, Chung-Kuang; Kidd, Richard D; Kanik, Isik

    2014-03-01

    In this paper, we discuss how prebiotic geo-electrochemical systems can be modeled as a fuel cell and how laboratory simulations of the origin of life in general can benefit from this systems-led approach. As a specific example, the components of what we have termed the "prebiotic fuel cell" (PFC) that operates at a putative Hadean hydrothermal vent are detailed, and we used electrochemical analysis techniques and proton exchange membrane (PEM) fuel cell components to test the properties of this PFC and other geo-electrochemical systems, the results of which are reported here. The modular nature of fuel cells makes them ideal for creating geo-electrochemical reactors with which to simulate hydrothermal systems on wet rocky planets and characterize the energetic properties of the seafloor/hydrothermal interface. That electrochemical techniques should be applied to simulating the origin of life follows from the recognition of the fuel cell-like properties of prebiotic chemical systems and the earliest metabolisms. Conducting this type of laboratory simulation of the emergence of bioenergetics will not only be informative in the context of the origin of life on Earth but may help in understanding whether life might emerge in similar environments on other worlds.

  10. The Use of a Real Life Simulated Problem Based Learning Activity in a Corporate Environment

    ERIC Educational Resources Information Center

    Laurent, Mark A.

    2013-01-01

    This narrative study examines using a real life simulated problem base learning activity during education of clinical staff, which is expected to design and develop clinically correct electronic charting systems. Expertise in healthcare does not readily transcend to the realm of manipulating software to collect patient data that is pertinent to…

  11. The Game of Social Life: An Assessment of a Multidimensional Poverty Simulation

    ERIC Educational Resources Information Center

    Bramesfeld, Kosha D.; Good, Arla

    2015-01-01

    This article presents the development of a new simulation activity, the Game of Social Life. The activity introduces students to concepts of social stratification based on multiple dimensions of poverty, including inequalities related to housing, education, occupational status, social power, and health outcomes. The game was administered to…

  12. CONFIG - Adapting qualitative modeling and discrete event simulation for design of fault management systems

    NASA Technical Reports Server (NTRS)

    Malin, Jane T.; Basham, Bryan D.

    1989-01-01

    CONFIG is a modeling and simulation tool prototype for analyzing the normal and faulty qualitative behaviors of engineered systems. Qualitative modeling and discrete-event simulation have been adapted and integrated, to support early development, during system design, of software and procedures for management of failures, especially in diagnostic expert systems. Qualitative component models are defined in terms of normal and faulty modes and processes, which are defined by invocation statements and effect statements with time delays. System models are constructed graphically by using instances of components and relations from object-oriented hierarchical model libraries. Extension and reuse of CONFIG models and analysis capabilities in hybrid rule- and model-based expert fault-management support systems are discussed.

  13. Parallel adaptive fluid-structure interaction simulation of explosions impacting on building structures

    SciTech Connect

    Deiterding, Ralf; Wood, Stephen L

    2013-01-01

    We pursue a level set approach to couple an Eulerian shock-capturing fluid solver with space-time refinement to an explicit solid dynamics solver for large deformations and fracture. The coupling algorithms considering recursively finer fluid time steps as well as overlapping solver updates are discussed in detail. Our ideas are implemented in the AMROC adaptive fluid solver framework and are used for effective fluid-structure coupling to the general purpose solid dynamics code DYNA3D. Beside simulations verifying the coupled fluid-structure solver and assessing its parallel scalability, the detailed structural analysis of a reinforced concrete column under blast loading and the simulation of a prototypical blast explosion in a realistic multistory building are presented.

  14. Accelerating the Convergence of Replica Exchange Simulations Using Gibbs Sampling and Adaptive Temperature Sets

    DOE PAGES

    Vogel, Thomas; Perez, Danny

    2015-08-28

    We recently introduced a novel replica-exchange scheme in which an individual replica can sample from states encountered by other replicas at any previous time by way of a global configuration database, enabling the fast propagation of relevant states through the whole ensemble of replicas. This mechanism depends on the knowledge of global thermodynamic functions which are measured during the simulation and not coupled to the heat bath temperatures driving the individual simulations. Therefore, this setup also allows for a continuous adaptation of the temperature set. In this paper, we will review the new scheme and demonstrate its capability. The methodmore » is particularly useful for the fast and reliable estimation of the microcanonical temperature T (U) or, equivalently, of the density of states g(U) over a wide range of energies.« less

  15. Accelerating the Convergence of Replica Exchange Simulations Using Gibbs Sampling and Adaptive Temperature Sets

    SciTech Connect

    Vogel, Thomas; Perez, Danny

    2015-08-28

    We recently introduced a novel replica-exchange scheme in which an individual replica can sample from states encountered by other replicas at any previous time by way of a global configuration database, enabling the fast propagation of relevant states through the whole ensemble of replicas. This mechanism depends on the knowledge of global thermodynamic functions which are measured during the simulation and not coupled to the heat bath temperatures driving the individual simulations. Therefore, this setup also allows for a continuous adaptation of the temperature set. In this paper, we will review the new scheme and demonstrate its capability. The method is particularly useful for the fast and reliable estimation of the microcanonical temperature T (U) or, equivalently, of the density of states g(U) over a wide range of energies.

  16. Adaptive MANET Multipath Routing Algorithm Based on the Simulated Annealing Approach

    PubMed Central

    Kim, Sungwook

    2014-01-01

    Mobile ad hoc network represents a system of wireless mobile nodes that can freely and dynamically self-organize network topologies without any preexisting communication infrastructure. Due to characteristics like temporary topology and absence of centralized authority, routing is one of the major issues in ad hoc networks. In this paper, a new multipath routing scheme is proposed by employing simulated annealing approach. The proposed metaheuristic approach can achieve greater and reciprocal advantages in a hostile dynamic real world network situation. Therefore, the proposed routing scheme is a powerful method for finding an effective solution into the conflict mobile ad hoc network routing problem. Simulation results indicate that the proposed paradigm adapts best to the variation of dynamic network situations. The average remaining energy, network throughput, packet loss probability, and traffic load distribution are improved by about 10%, 10%, 5%, and 10%, respectively, more than the existing schemes. PMID:25032241

  17. 3D Adaptive Mesh Refinement Simulations of Pellet Injection in Tokamaks

    SciTech Connect

    R. Samtaney; S.C. Jardin; P. Colella; D.F. Martin

    2003-10-20

    We present results of Adaptive Mesh Refinement (AMR) simulations of the pellet injection process, a proven method of refueling tokamaks. AMR is a computationally efficient way to provide the resolution required to simulate realistic pellet sizes relative to device dimensions. The mathematical model comprises of single-fluid MHD equations with source terms in the continuity equation along with a pellet ablation rate model. The numerical method developed is an explicit unsplit upwinding treatment of the 8-wave formulation, coupled with a MAC projection method to enforce the solenoidal property of the magnetic field. The Chombo framework is used for AMR. The role of the E x B drift in mass redistribution during inside and outside pellet injections is emphasized.

  18. An Adaptive Semi-Implicit Scheme for Simulations of Unsteady Viscous Compressible Flows

    NASA Technical Reports Server (NTRS)

    Steinthorsson, Erlendur; Modiano, David; Crutchfield, William Y.; Bell, John B.; Colella, Phillip

    1995-01-01

    A numerical scheme for simulation of unsteady, viscous, compressible flows is considered. The scheme employs an explicit discretization of the inviscid terms of the Navier-Stokes equations and an implicit discretization of the viscous terms. The discretization is second order accurate in both space and time. Under appropriate assumptions, the implicit system of equations can be decoupled into two linear systems of reduced rank. These are solved efficiently using a Gauss-Seidel method with multigrid convergence acceleration. When coupled with a solution-adaptive mesh refinement technique, the hybrid explicit-implicit scheme provides an effective methodology for accurate simulations of unsteady viscous flows. The methodology is demonstrated for both body-fitted structured grids and for rectangular (Cartesian) grids.

  19. A GPU implementation of adaptive mesh refinement to simulate tsunamis generated by landslides

    NASA Astrophysics Data System (ADS)

    de la Asunción, Marc; Castro, Manuel J.

    2016-04-01

    In this work we propose a CUDA implementation for the simulation of landslide-generated tsunamis using a two-layer Savage-Hutter type model and adaptive mesh refinement (AMR). The AMR method consists of dynamically increasing the spatial resolution of the regions of interest of the domain while keeping the rest of the domain at low resolution, thus obtaining better runtimes and similar results compared to increasing the spatial resolution of the entire domain. Our AMR implementation uses a patch-based approach, it supports up to three levels, power-of-two ratios of refinement, different refinement criteria and also several user parameters to control the refinement and clustering behaviour. A strategy based on the variation of the cell values during the simulation is used to interpolate and propagate the values of the fine cells. Several numerical experiments using artificial and realistic scenarios are presented.

  20. MPI parallelization of full PIC simulation code with Adaptive Mesh Refinement

    NASA Astrophysics Data System (ADS)

    Matsui, Tatsuki; Nunami, Masanori; Usui, Hideyuki; Moritaka, Toseo

    2010-11-01

    A new parallelization technique developed for PIC method with adaptive mesh refinement (AMR) is introduced. In AMR technique, the complicated cell arrangements are organized and managed as interconnected pointers with multiple resolution levels, forming a fully threaded tree structure as a whole. In order to retain this tree structure distributed over multiple processes, remote memory access, an extended feature of MPI2 standards, is employed. Another important feature of the present simulation technique is the domain decomposition according to the modified Morton ordering. This algorithm can group up the equal number of particle calculation loops, which allows for the better load balance. Using this advanced simulation code, preliminary results for basic physical problems are exhibited for the validity check, together with the benchmarks to test the performance and the scalability.

  1. A time-accurate adaptive grid method and the numerical simulation of a shock-vortex interaction

    NASA Technical Reports Server (NTRS)

    Bockelie, Michael J.; Eiseman, Peter R.

    1990-01-01

    A time accurate, general purpose, adaptive grid method is developed that is suitable for multidimensional steady and unsteady numerical simulations. The grid point movement is performed in a manner that generates smooth grids which resolve the severe solution gradients and the sharp transitions in the solution gradients. The temporal coupling of the adaptive grid and the PDE solver is performed with a grid prediction correction method that is simple to implement and ensures the time accuracy of the grid. Time accurate solutions of the 2-D Euler equations for an unsteady shock vortex interaction demonstrate the ability of the adaptive method to accurately adapt the grid to multiple solution features.

  2. Evolution of complex life cycles in trophically transmitted helminths. II. How do life-history stages adapt to their hosts?

    PubMed

    Parker, G A; Ball, M A; Chubb, J C

    2015-02-01

    We review how trophically transmitted helminths adapt to the special problems associated with successive hosts in complex cycles. In intermediate hosts, larvae typically show growth arrest at larval maturity (GALM). Theoretical models indicate that optimization of size at GALM requires larval mortality rate to increase with time between infection and GALM: low larval growth or paratenicity (no growth) arises from unfavourable growth and mortality rates in the intermediate host and low transmission rates to the definitive host. Reverse conditions favour high GALM size or continuous growth. Some support is found for these predictions. Intermediate host manipulation involves predation suppression (which decreases host vulnerability before the larva can establish in its next host) and predation enhancement (which increases host vulnerability after the larva can establish in its next host). Switches between suppression and enhancement suggest adaptive manipulation. Manipulation conflicts can occur between larvae of different ages/species a host individual. Larvae must usually develop to GALM before becoming infective to the next host, possibly due to trade-offs, e.g. between growth/survival in the present host and infection ability for the next host. In definitive hosts, if mortality rate is constant, optimal growth before switching to reproduction is set by the growth/morality rate ratio. Rarely, no growth occurs in definitive hosts, predicted (with empirical support) when larval size on infection exceeds growth/mortality rate. Tissue migration patterns and residence sites may be explained by variations in growth/mortality rates between host gut and soma, migration costs and benefits of releasing eggs in the gut.

  3. ADRC or adaptive controller--A simulation study on artificial blood pump.

    PubMed

    Wu, Yi; Zheng, Qing

    2015-11-01

    Active disturbance rejection control (ADRC) has gained popularity because it requires little knowledge about the system to be controlled, has the inherent disturbance rejection ability, and is easy to tune and implement in practical systems. In this paper, the authors compared the performance of an ADRC and an adaptive controller for an artificial blood pump for end-stage congestive heart failure patients using only the feedback signal of pump differential pressure. The purpose of the control system was to provide sufficient perfusion when the patients' circulation system goes through different pathological and activity variations. Because the mean arterial pressure is equal to the total peripheral flow times the total peripheral resistance, this goal was converted to an expression of making the mean aortic pressure track a reference signal. The simulation results demonstrated that the performance of the ADRC is comparable to that of the adaptive controller with the saving of modeling and computational effort and fewer design parameters: total peripheral flow and mean aortic pressure with ADRC fall within the normal physiological ranges in activity variation (rest to exercise) and in pathological variation (left ventricular strength variation), similar to those values of adaptive controller.

  4. Simulating spatial adaption of groundwater pumping on seawater intrusion in coastal regions

    NASA Astrophysics Data System (ADS)

    Grundmann, Jens; Ladwig, Robert; Schütze, Niels; Walther, Marc

    2016-04-01

    Coastal aquifer systems are used intensively to meet the growing demands for water in those regions. They are especially at risk for the intrusion of seawater due to aquifer overpumping, limited groundwater replenishment and unsustainable groundwater management which in turn also impacts the social and economical development of coastal regions. One example is the Al-Batinah coastal plain in northern Oman where irrigated agriculture is practiced by lots of small scaled farms in different distances from the sea, each of them pumping their water from coastal aquifer. Due to continuous overpumping and progressing saltwater intrusion farms near the coast had to close since water for irrigation got too saline. For investigating appropriate management options numerical density dependent groundwater modelling is required which should also portray the adaption of groundwater abstraction schemes on the water quality. For addressing this challenge a moving inner boundary condition is implemented in the numerical density dependent groundwater model which adjusts the locations for groundwater abstraction according to the position of the seawater intrusion front controlled by thresholds of relative chloride concentration. The adaption process is repeated for each management cycle within transient model simulations and allows for considering feedbacks with the consumers e.g. the agriculture by moving agricultural farms more inland or towards the sea if more fertile soils at the coast could be recovered. For finding optimal water management strategies efficiently, the behaviour of the numerical groundwater model for different extraction and replenishment scenarios is approximated by an artificial neural network using a novel approach for state space surrogate model development. Afterwards the derived surrogate is coupled with an agriculture module within a simulation based water management optimisation framework to achieve optimal cropping pattern and water abstraction schemes

  5. Effect of imperfect detectability on adaptive and conventional sampling: Simulated sampling of freshwater mussels in the upper Mississippi River

    USGS Publications Warehouse

    Smith, D.R.; Gray, B.R.; Newton, T.J.; Nichols, D.

    2010-01-01

    Adaptive sampling designs are recommended where, as is typical with freshwater mussels, the outcome of interest is rare and clustered. However, the performance of adaptive designs has not been investigated when outcomes are not only rare and clustered but also imperfectly detected. We address this combination of challenges using data simulated to mimic properties of freshwater mussels from a reach of the upper Mississippi River. Simulations were conducted under a range of sample sizes and detection probabilities. Under perfect detection, efficiency of the adaptive sampling design increased relative to the conventional design as sample size increased and as density decreased. Also, the probability of sampling occupied habitat was four times higher for adaptive than conventional sampling of the lowest density population examined. However, imperfect detection resulted in substantial biases in sample means and variances under both adaptive sampling and conventional designs. The efficiency of adaptive sampling declined with decreasing detectability. Also, the probability of encountering an occupied unit during adaptive sampling, relative to conventional sampling declined with decreasing detectability. Thus, the potential gains in the application of adaptive sampling to rare and clustered populations relative to conventional sampling are reduced when detection is imperfect. The results highlight the need to increase or estimate detection to improve performance of conventional and adaptive sampling designs.

  6. Effect of imperfect detectability on adaptive and conventional sampling: simulated sampling of freshwater mussels in the upper Mississippi River.

    PubMed

    Smith, David R; Gray, Brian R; Newton, Teresa J; Nichols, Doug

    2010-11-01

    Adaptive sampling designs are recommended where, as is typical with freshwater mussels, the outcome of interest is rare and clustered. However, the performance of adaptive designs has not been investigated when outcomes are not only rare and clustered but also imperfectly detected. We address this combination of challenges using data simulated to mimic properties of freshwater mussels from a reach of the upper Mississippi River. Simulations were conducted under a range of sample sizes and detection probabilities. Under perfect detection, efficiency of the adaptive sampling design increased relative to the conventional design as sample size increased and as density decreased. Also, the probability of sampling occupied habitat was four times higher for adaptive than conventional sampling of the lowest density population examined. However, imperfect detection resulted in substantial biases in sample means and variances under both adaptive sampling and conventional designs. The efficiency of adaptive sampling declined with decreasing detectability. Also, the probability of encountering an occupied unit during adaptive sampling, relative to conventional sampling declined with decreasing detectability. Thus, the potential gains in the application of adaptive sampling to rare and clustered populations relative to conventional sampling are reduced when detection is imperfect. The results highlight the need to increase or estimate detection to improve performance of conventional and adaptive sampling designs.

  7. Simulation of metal forming processes with a 3D adaptive remeshing procedure

    NASA Astrophysics Data System (ADS)

    Zeramdini, Bessam; Robert, Camille; Germain, Guenael; Pottier, Thomas

    2016-10-01

    In this paper, a fully adaptive 3D numerical methodology based on a tetrahedral element was proposed in order to improve the finite element simulation of any metal forming process. This automatic methodology was implemented in a computational platform which integrates a finite element solver, 3D mesh generation and a field transfer algorithm. The proposed remeshing method was developed in order to solve problems associated with the severe distortion of elements subject to large deformations, to concentrate the elements where the error is large and to coarsen the mesh where the error is small. This leads to a significant reduction in the computation times while maintaining simulation accuracy. In addition, in order to enhance the contact conditions, this method has been coupled with a specific operator to maintain the initial contact between the workpiece nodes and the rigid tool after each remeshing step. In this paper special attention is paid to the data transfer methods and the necessary adaptive remeshing steps are given. Finally, a numerical example is detailed to demonstrate the efficiency of the approach and to compare the results for the different field transfer strategies.

  8. Scale-adaptive subgrid-scale modelling for large-eddy simulation of turbulent flows

    NASA Astrophysics Data System (ADS)

    Yu, Changping; Xiao, Zuoli; Li, Xinliang

    2017-03-01

    The proportionality between the subgrid-scale (SGS) drain rate of kinetic energy and the viscous dissipation rate of the resolved motions is studied a priori by filtering a given fully resolved field and evaluating a generic form of the hypothesized energy spectrum. The ratio of the SGS drain to the resolved dissipation, on which a balance condition for the SGS dissipation across an arbitrary grid scale is founded, is shown to be independent of the turbulence Reynolds number, and can be described by a function in terms of the averaged mesh Reynolds number. Such a balance condition can serve as a physical constraint in the SGS modeling to account for the scale effects of the model coefficient(s). Scale-adaptive dynamic Smagorinsky-Lilly model and mixed nonlinear model are formulated for large-eddy simulation of transitional and/or turbulent flows in such a way that the constraint is satisfied. The newly proposed scale-adaptive dynamic SGS models are validated in simulations of homogeneous isotropic turbulence and turbulent channel flow, and prove to be superior over traditional dynamic SGS models.

  9. Radiation hydrodynamics using characteristics on adaptive decomposed domains for massively parallel star formation simulations

    NASA Astrophysics Data System (ADS)

    Buntemeyer, Lars; Banerjee, Robi; Peters, Thomas; Klassen, Mikhail; Pudritz, Ralph E.

    2016-02-01

    We present an algorithm for solving the radiative transfer problem on massively parallel computers using adaptive mesh refinement and domain decomposition. The solver is based on the method of characteristics which requires an adaptive raytracer that integrates the equation of radiative transfer. The radiation field is split into local and global components which are handled separately to overcome the non-locality problem. The solver is implemented in the framework of the magneto-hydrodynamics code FLASH and is coupled by an operator splitting step. The goal is the study of radiation in the context of star formation simulations with a focus on early disc formation and evolution. This requires a proper treatment of radiation physics that covers both the optically thin as well as the optically thick regimes and the transition region in particular. We successfully show the accuracy and feasibility of our method in a series of standard radiative transfer problems and two 3D collapse simulations resembling the early stages of protostar and disc formation.

  10. AMRSim: an object-oriented performance simulator for parallel adaptive mesh refinement

    SciTech Connect

    Miller, B; Philip, B; Quinlan, D; Wissink, A

    2001-01-08

    Adaptive mesh refinement is complicated by both the algorithms and the dynamic nature of the computations. In parallel the complexity of getting good performance is dependent upon the architecture and the application. Most attempts to address the complexity of AMR have lead to the development of library solutions, most have developed object-oriented libraries or frameworks. All attempts to date have made numerous and sometimes conflicting assumptions which make the evaluation of performance of AMR across different applications and architectures difficult or impracticable. The evaluation of different approaches can alternatively be accomplished through simulation of the different AMR processes. In this paper we outline our research work to simulate the processing of adaptive mesh refinement grids using a distributed array class library (P++). This paper presents a combined analytic and empirical approach, since details of the algorithms can be readily predicted (separated into specific phases), while the performance associated with the dynamic behavior must be studied empirically. The result, AMRSim, provides a simple way to develop bounds on the expected performance of AMR calculations subject to constraints given by the algorithms, frameworks, and architecture.

  11. Adaptive multi-stage integrators for optimal energy conservation in molecular simulations

    NASA Astrophysics Data System (ADS)

    Fernández-Pendás, Mario; Akhmatskaya, Elena; Sanz-Serna, J. M.

    2016-12-01

    We introduce a new Adaptive Integration Approach (AIA) to be used in a wide range of molecular simulations. Given a simulation problem and a step size, the method automatically chooses the optimal scheme out of an available family of numerical integrators. Although we focus on two-stage splitting integrators, the idea may be used with more general families. In each instance, the system-specific integrating scheme identified by our approach is optimal in the sense that it provides the best conservation of energy for harmonic forces. The AIA method has been implemented in the BCAM-modified GROMACS software package. Numerical tests in molecular dynamics and hybrid Monte Carlo simulations of constrained and unconstrained physical systems show that the method successfully realizes the fail-safe strategy. In all experiments, and for each of the criteria employed, the AIA is at least as good as, and often significantly outperforms the standard Verlet scheme, as well as fixed parameter, optimized two-stage integrators. In particular, for the systems where harmonic forces play an important role, the sampling efficiency found in simulations using the AIA is up to 5 times better than the one achieved with other tested schemes.

  12. Determining thresholds using adaptive procedures and psychometric fits: evaluating efficiency using theory, simulations, and human experiments.

    PubMed

    Karmali, Faisal; Chaudhuri, Shomesh E; Yi, Yongwoo; Merfeld, Daniel M

    2016-03-01

    When measuring thresholds, careful selection of stimulus amplitude can increase efficiency by increasing the precision of psychometric fit parameters (e.g., decreasing the fit parameter error bars). To find efficient adaptive algorithms for psychometric threshold ("sigma") estimation, we combined analytic approaches, Monte Carlo simulations, and human experiments for a one-interval, binary forced-choice, direction-recognition task. To our knowledge, this is the first time analytic results have been combined and compared with either simulation or human results. Human performance was consistent with theory and not significantly different from simulation predictions. Our analytic approach provides a bound on efficiency, which we compared against the efficiency of standard staircase algorithms, a modified staircase algorithm with asymmetric step sizes, and a maximum likelihood estimation (MLE) procedure. Simulation results suggest that optimal efficiency at determining threshold is provided by the MLE procedure targeting a fraction correct level of 0.92, an asymmetric 4-down, 1-up staircase targeting between 0.86 and 0.92 or a standard 6-down, 1-up staircase. Psychometric test efficiency, computed by comparing simulation and analytic results, was between 41 and 58% for 50 trials for these three algorithms, reaching up to 84% for 200 trials. These approaches were 13-21% more efficient than the commonly used 3-down, 1-up symmetric staircase. We also applied recent advances to reduce accuracy errors using a bias-reduced fitting approach. Taken together, the results lend confidence that the assumptions underlying each approach are reasonable and that human threshold forced-choice decision making is modeled well by detection theory models and mimics simulations based on detection theory models.

  13. Conversations With My Father: Adapting "A Musical Chronology and the Emerging Life Song" with Older Adults

    ERIC Educational Resources Information Center

    Duffey, Thelma; Somody, Catherine; Clifford, Sue

    2007-01-01

    This article provides a brief review of the literature describing successful aging life tasks, such as reminiscence, meaning-making, and forming substantive connections. Using Relational-Cultural Theory as a base, the article addresses the need for connection and ways that connections can be developed and sustained in later life. Through a…

  14. Mini-Review: Probing the limits of extremophilic life in extraterrestrial environment-simulated experiments

    NASA Astrophysics Data System (ADS)

    Lage, Claudia A. S.; Dalmaso, Gabriel Z. L.; Teixeira, Lia C. R. S.; Bendia, Amanda G.; Paulino-Lima, Ivan G.; Galante, Douglas; Janot-Pacheco, Eduardo; Abrevaya, Ximena C.; Azúa-Bustos, Armando; Pelizzari, Vivian H.; Rosado, Alexandre S.

    2012-10-01

    Astrobiology is a relatively recent scientific field that seeks to understand the origin and dynamics of life in the Universe. Several hypotheses have been proposed to explain life in the cosmic context throughout human history, but only now, technology has allowed many of them to be tested. Laboratory experiments have been able to show how chemical elements essential to life, such as carbon, nitrogen, oxygen and hydrogen combine in biologically important compounds. Interestingly, these compounds are ubiquitous. How these compounds were combined to the point of originating cells and complex organisms is still to be unveiled by science. However, our 4.5 billion years old Solar system appeared in a 10 billion years old Universe. Thus, simple cells such as micro-organisms may have had time to form in planets older than ours or in other suitable places in the Universe. One hypothesis related to the appearance of life on Earth is called panspermia, which predicts that microbial life could have been formed in the Universe billions of years ago, travelling between planets, and inseminating units of life that could have become more complex in habitable planets such as Earth. A project designed to test the viability of extremophile micro-organisms exposed to simulated extraterrestrial environments is in progress at the Carlos Chagas Filho Institute of Biophysics (UFRJ, Brazil) to test whether microbial life could withstand inhospitable environments. Radiation-resistant (known or novel ones) micro-organisms collected from extreme terrestrial environments have been exposed (at synchrotron accelerators) to intense radiation sources simulating Solar radiation, capable of emitting radiation in a few hours equivalent to many years of accumulated doses. The results obtained in these experiments reveal an interesting possibility of the existence of microbial life beyond Earth.

  15. The limits of extremophilic life expanded under extraterrestrial environment-simulated experiments

    NASA Astrophysics Data System (ADS)

    Lage, C.; Dalmaso, G.; Teixeira, L.; Bendia, A.; Rosado, A.

    2012-09-01

    Astrobiology is a brand new area of science that seeks to understand the origin and dynamics of life in the universe. Several hypotheses to explain life in the cosmic context have been developed throughout human history, but only now technology has allowed many of them to be tested. Laboratory experiments have been able to show how chemical elements essential to life, carbon, nitrogen, oxygen and hydrogen combine in biologically important compounds. Interestingly, these compounds are found universally. As these compounds were combined to the point of originating cells and complex organisms is still a challenge to be unveiled by science. However, our 4.5 billion years-old solar system was born within a 10-billion years-old universe. Thus, simple cells like microorganisms may have had time to form in planets older than ours or other suitable molecular places in the universe. One hypothesis to explain the origin of life on Earth is called panspermia, which predicts that microbial life could have been formed in the universe billions of years ago, traveling between planets, and inseminating units of life that could have become more complex in habitable planets like ours. A project designed to test the viability of extremophile microorganisms exposed to simulated extraterrestrial environments is ongoing at the Carlos Chagas Filho Institute of Biophysics to test whether microbial life could withstand those inhospitable environments. Ultra-resistant (known or novel ones) microorganisms collected from terrestrial extreme environments, extremophiles, have been exposed to intense radiation sources simulating solar radiation (at synchrotron accelerators), capable of emitting in a few hours radiation equivalent of million years accumulated doses. The results obtained in these experiments reveal the interesting possibility of the existence of microbial life beyond Earth.

  16. [Transcultural adaptation of the HIV/AIDS-Target Quality of Life for HIV/AIDS for the evaluation of patients' quality of life].

    PubMed

    Moser, Ana Maria Martins; Traebert, Jefferson

    2011-01-01

    The objectives of this study were to carry out cross-cultural adaptation of the HIV/AIDS-Target Quality of Life Instrument for Portuguese and to observe its psychometric properties. Translations, translations synthesis, back translation, analysis by a committee of specialists, pre-final version test, studies of validity and reliability of the final version were carried out. Psychometric properties were evaluated by the administration of the Brazilian version in 50 consecutive HIV positive patients, from the DST/HIV/AIDS municipal ambulatory of São Miguel do Oeste, Santa Catarina State. The internal consistency was observed by a-Cronbach. The reliability was estimated using the intraclass correlation coefficient and Bland-Altmann diagram. The validity was observed comparing the scores of the questionnaire with the WHOQOL-HIV-Brief through the Spearman rank correlation coefficient. The results pointed out to a-Cronbach of 0.893. The correlations obtained were 0.934 for inter-interviewer and 0.977 for intra-interviewer. The correlation with WHOQOL-HIV-Bref was 0.824. It was concluded that the cross-cultural adaptation process was successful and the adapted questionnaire demonstrated good psychometric properties.

  17. Toxic hydrogen sulphide and dark caves: pronounced male life-history divergence among locally adapted Poecilia mexicana (Poeciliidae).

    PubMed

    Riesch, R; Plath, M; Schlupp, I

    2011-03-01

    Chronic environmental stress is known to induce evolutionary change. Here, we assessed male life-history trait divergence in the neotropical fish Poecilia mexicana from a system that has been described to undergo incipient ecological speciation in adjacent, but reproductively isolated toxic/nontoxic and surface/cave habitats. Examining both field-caught and common garden-reared specimens, we investigated the extent of differentiation and plasticity of life-history strategies employed by male P. mexicana. We found strong site-specific life-history divergence in traits such as fat content, standard length and gonadosomatic index. The majority of site-specific life-history differences were also expressed under common garden-rearing conditions. We propose that apparent conservatism of male life histories is the result of other (genetically based) changes in physiology and behaviour between populations. Together with the results from previous studies, this is strong evidence for local adaptation as a result of ecologically based divergent selection.

  18. Preliminary Benchmarking of Plinian Eruption Simulations Using an Adaptive Grid Eulerian Technique

    NASA Astrophysics Data System (ADS)

    Peterson, A. H.; Ogden, D. E.; Wohletz, K. H.; Gisler, G.; Glatzmaier, G. A.

    2005-12-01

    The SAGE (SAIC Adaptive Grid Eulerian) code is an Eulerian hydrodynamics numerical technique employing adaptive mesh refinement at each cycle for every cell in 1-, 2-, and 3-D grids. It is primarily designed to solve high deformation flow of multiple materials and thus provides important capabilities for simulating volcanic eruption phenomena. Its multimaterial equation of state libraries includes a comprehensive coverage of water from solid ice through two-phase liquid and vapor to supercritical states approaching the Hugoniot, and extremely important aspect for simulating volcanic gases in general. In development are strength and failure rules that model non-Newtonian fluid/solid deformation. Because of the low effective sound speeds of eruptive mixtures, the facts that SAGE uses a piecewise, linear, multi-material, Gudonov numerical method to resolve shocks with second-order precision and exactly conserves mass, momentum, and energy, are a highly desirable attributes. Although this code has been previously used to simulate a volcanic eruption (i.e., eruption through a crater lake at Ruapehu volcano by Morrissey and Gisler), we are embarking in an effort to benchmark the code with CFDLib, a well-validated arbitrary Lagrangian-Eulerian code developed at Los Alamos National Laboratory. Through this effort we expect to better understand the strengths and weaknesses, the limitations, and provide direction for important enhancement of SAGE, and potentially provide the volcanological community with a powerful alternative to numerical codes currently available. At this point in our benchmarking, we demonstrate some results for fluid convection within a chamber and fluid jetting through a conduit.

  19. Adaptive Challenges Rising from the Life Context of African-American Caregiving Grandmothers with Diabetes: A Pilot Study

    PubMed Central

    Carthron, Dana; Bailey, Donald E.; Anderson, Ruth

    2015-01-01

    To understand the challenges arising from the context within which diabetic African-American caregiving grandmothers self-manage their diabetes we used the Adaptive Leadership Framework. Additionally, challenges to retaining this population in a longitudinal study were examined. In this exploratory, longitudinal, qualitative pilot study, data were collected at five time-points over 18 months. We coded the data using content analysis and conducted the within-case and cross-case analyses using data matrices. Lack of awareness of available resources, represented a technical challenge within the life context of these grandmothers and the remaining three themes: family upheaval; priority setting (with subthemes of difficulty meeting basic needs and competing demands); and self-silencing and self-sacrifice represented adaptive challenges. The context of African-American grandmothers’ lives created primarily adaptive challenges that were complex and without immediate solutions. Research is needed to develop culturally and contextually appropriate interventions to help this vulnerable group develop capacity for adaptive work. PMID:27064619

  20. Multiple-task performance on a computer-simulated life support system during a space mission simulation.

    PubMed

    Sauer, J; Wastell, D G; Hockey, G R

    1999-01-01

    This paper presents an experiment which examined the effects of isolation and confinement during a simulation of a short-term space mission. During the 7-day spaceflight simulation, four Canadian astronauts were tested daily on a 30-min performance task. The task, CAMS (Cabin Air Management System), represents a computer-based simulation of a generic life support system. As a multiple-task environment, it allows the measurement of a wide range of task management variables such as primary and secondary task performance, and system control activities. Measures of subjective state variables were also taken. The results did not show any evidence of serious performance decrements for any crew member. The analysis revealed different adjustment patterns with which crew members responded as a function of mission duration and variations in workload. Among the secondary tasks employed, prospective memory was found to be more sensitive than reaction time to increases in workload. The paper concludes with a discussion of the utility of spaceflight simulations and computer-based simulations of space work.

  1. An adaptive multi-level simulation algorithm for stochastic biological systems.

    PubMed

    Lester, C; Yates, C A; Giles, M B; Baker, R E

    2015-01-14

    Discrete-state, continuous-time Markov models are widely used in the modeling of biochemical reaction networks. Their complexity often precludes analytic solution, and we rely on stochastic simulation algorithms (SSA) to estimate system statistics. The Gillespie algorithm is exact, but computationally costly as it simulates every single reaction. As such, approximate stochastic simulation algorithms such as the tau-leap algorithm are often used. Potentially computationally more efficient, the system statistics generated suffer from significant bias unless tau is relatively small, in which case the computational time can be comparable to that of the Gillespie algorithm. The multi-level method [Anderson and Higham, "Multi-level Monte Carlo for continuous time Markov chains, with applications in biochemical kinetics," SIAM Multiscale Model. Simul. 10(1), 146-179 (2012)] tackles this problem. A base estimator is computed using many (cheap) sample paths at low accuracy. The bias inherent in this estimator is then reduced using a number of corrections. Each correction term is estimated using a collection of paired sample paths where one path of each pair is generated at a higher accuracy compared to the other (and so more expensive). By sharing random variables between these paired paths, the variance of each correction estimator can be reduced. This renders the multi-level method very efficient as only a relatively small number of paired paths are required to calculate each correction term. In the original multi-level method, each sample path is simulated using the tau-leap algorithm with a fixed value of τ. This approach can result in poor performance when the reaction activity of a system changes substantially over the timescale of interest. By introducing a novel adaptive time-stepping approach where τ is chosen according to the stochastic behaviour of each sample path, we extend the applicability of the multi-level method to such cases. We demonstrate the

  2. Local Adaptation at the Transcriptome Level in Brown Trout: Evidence from Early Life History Temperature Genomic Reaction Norms

    PubMed Central

    Meier, Kristian; Hansen, Michael Møller; Normandeau, Eric; Mensberg, Karen-Lise D.; Frydenberg, Jane; Larsen, Peter Foged; Bekkevold, Dorte; Bernatchez, Louis

    2014-01-01

    Local adaptation and its underlying molecular basis has long been a key focus in evolutionary biology. There has recently been increased interest in the evolutionary role of plasticity and the molecular mechanisms underlying local adaptation. Using transcriptome analysis, we assessed differences in gene expression profiles for three brown trout (Salmo trutta) populations, one resident and two anadromous, experiencing different temperature regimes in the wild. The study was based on an F2 generation raised in a common garden setting. A previous study of the F1 generation revealed different reaction norms and significantly higher QST than FST among populations for two early life-history traits. In the present study we investigated if genomic reaction norm patterns were also present at the transcriptome level. Eggs from the three populations were incubated at two temperatures (5 and 8 degrees C) representing conditions encountered in the local environments. Global gene expression for fry at the stage of first feeding was analysed using a 32k cDNA microarray. The results revealed differences in gene expression between populations and temperatures and population × temperature interactions, the latter indicating locally adapted reaction norms. Moreover, the reaction norms paralleled those observed previously at early life-history traits. We identified 90 cDNA clones among the genes with an interaction effect that were differently expressed between the ecologically divergent populations. These included genes involved in immune- and stress response. We observed less plasticity in the resident as compared to the anadromous populations, possibly reflecting that the degree of environmental heterogeneity encountered by individuals throughout their life cycle will select for variable level of phenotypic plasticity at the transcriptome level. Our study demonstrates the usefulness of transcriptome approaches to identify genes with different temperature reaction norms. The

  3. Psychosocial stress based on public speech in humans: is there a real life/laboratory setting cross-adaptation?

    PubMed

    Jezova, D; Hlavacova, N; Dicko, I; Solarikova, P; Brezina, I

    2016-07-01

    Repeated or chronic exposure to stressors is associated with changes in neuroendocrine responses depending on the type, intensity, number and frequency of stress exposure as well as previous stress experience. The aim of the study was to test the hypothesis that salivary cortisol and cardiovascular responses to real-life psychosocial stressors related to public performance can cross-adapt with responses to psychosocial stress induced by public speech under laboratory setting. The sample consisted of 22 healthy male volunteers, which were either actors, more precisely students of dramatic arts or non-actors, students of other fields. The stress task consisted of 15 min anticipatory preparation phase and 15 min of public speech on an emotionally charged topic. The actors, who were accustomed to public speaking, responded with a rise in salivary cortisol as well as blood pressure to laboratory public speech. The values of salivary cortisol, systolic blood pressure and state anxiety were lower in actors compared to non-actors. Unlike non-actors, subjects with experience in public speaking did not show stress-induced rise in the heart rate. Evaluation of personality traits revealed that actors scored significantly higher in extraversion than the subjects in the non-actor group. In conclusion, neuroendocrine responses to real-life stressors in actors can partially cross-adapt with responses to psychosocial stress under laboratory setting. The most evident adaptation was at the level of heart rate responses. The public speech tasks may be of help in evaluation of the ability to cope with stress in real life in artists by simple laboratory testing.

  4. Adaptive Optics: Arroyo Simulation Tool and Deformable Mirror Actuation Using Golay Cells

    NASA Technical Reports Server (NTRS)

    Lint, Adam S.

    2005-01-01

    The Arroyo C++ libraries, written by Caltech post-doc student Matthew Britton, have the ability to simulate optical systems and atmospheric signal interference. This program was chosen for use in an end-to-end simulation model of a laser communication system because it is freely distributed and has the ability to be controlled by a remote system or "smart agent." Proposed operation of this program by a smart agent has been demonstrated, and the results show it to be a suitable simulation tool. Deformable mirrors, as a part of modern adaptive optics systems, may contain thousands of tiny, independently controlled actuators used to modify the shape of the mirror. Each actuator is connected to two wires, creating a cumbersome and expensive device. Recently, an alternative actuation method that uses gas-filled tubes known as Golay cells has been explored. Golay cells, operated by infrared lasers instead of electricity, would replace the actuator system thereby creating a more compact deformable mirror. The operation of Golay cells and their ability to move a deformable mirror in excess of the required 20 microns has been demonstrated. Experimentation has shown them to be extremely sensitive to pressure and temperature, making them ideal for use in a controlled environment.

  5. Simulations of Adaptive Optics with a Laser Guide Star for SINFONI

    NASA Astrophysics Data System (ADS)

    Brown, Anthony G. A.; Fedrigo, Enrico; van der Werf, Paul

    The SINFONI (SINgle Far Object Near-ir Investigation) instrument is developed jointly by ESO, MPE and NOVA, and combines integral field spectroscopy with adaptive optics in one instrument [1,2]. The instrument will be available at ESO's VLT in 2004. The AO module of the instrument is based on a 60-element curvature wavefront sensor (CWS) combined with a bimorph deformable mirror. It will operate in natural (NGS) and laser guide star (LGS) mode and will feed the corrected PSF to the near-infrared integral field spectrograph SPIFFI [2]. As part of the NOVA contribution to this project detailed simulations of an AO system with a curvature sensor, tailored to the details of the SINFONI AO module, are being carried out. The aim is to develop a realistic simulation of the operation of the AO module with a laser guide star generated in the mesospheric sodium layer. The output consists of detailed statistics of the AO system performance as well as PSF images (at J, H, and K-band) and wavefront sensor data. The results will be used to support the development of algorithms for PSF reconstruction from wavefront sensor data and the development of an exposure time calculator. Scientific preparations for the use of the SINFONI instrument will also be supported with these simulations.

  6. Numerical simulation of current sheet formation in a quasiseparatrix layer using adaptive mesh refinement

    SciTech Connect

    Effenberger, Frederic; Thust, Kay; Grauer, Rainer; Dreher, Juergen; Arnold, Lukas

    2011-03-15

    The formation of a thin current sheet in a magnetic quasiseparatrix layer (QSL) is investigated by means of numerical simulation using a simplified ideal, low-{beta}, MHD model. The initial configuration and driving boundary conditions are relevant to phenomena observed in the solar corona and were studied earlier by Aulanier et al. [Astron. Astrophys. 444, 961 (2005)]. In extension to that work, we use the technique of adaptive mesh refinement (AMR) to significantly enhance the local spatial resolution of the current sheet during its formation, which enables us to follow the evolution into a later stage. Our simulations are in good agreement with the results of Aulanier et al. up to the calculated time in that work. In a later phase, we observe a basically unarrested collapse of the sheet to length scales that are more than one order of magnitude smaller than those reported earlier. The current density attains correspondingly larger maximum values within the sheet. During this thinning process, which is finally limited by lack of resolution even in the AMR studies, the current sheet moves upward, following a global expansion of the magnetic structure during the quasistatic evolution. The sheet is locally one-dimensional and the plasma flow in its vicinity, when transformed into a comoving frame, qualitatively resembles a stagnation point flow. In conclusion, our simulations support the idea that extremely high current densities are generated in the vicinities of QSLs as a response to external perturbations, with no sign of saturation.

  7. Adaptive resolution simulation of polarizable supramolecular coarse-grained water models

    SciTech Connect

    Zavadlav, Julija; Praprotnik, Matej; Melo, Manuel N.; Marrink, Siewert J.

    2015-06-28

    Multiscale simulations methods, such as adaptive resolution scheme, are becoming increasingly popular due to their significant computational advantages with respect to conventional atomistic simulations. For these kind of simulations, it is essential to develop accurate multiscale water models that can be used to solvate biophysical systems of interest. Recently, a 4-to-1 mapping was used to couple the bundled-simple point charge water with the MARTINI model. Here, we extend the supramolecular mapping to coarse-grained models with explicit charges. In particular, the two tested models are the polarizable water and big multiple water models associated with the MARTINI force field. As corresponding coarse-grained representations consist of several interaction sites, we couple orientational degrees of freedom of the atomistic and coarse-grained representations via a harmonic energy penalty term. This additional energy term aligns the dipole moments of both representations. We test this coupling by studying the system under applied static external electric field. We show that our approach leads to the correct reproduction of the relevant structural and dynamical properties.

  8. 3D Boltzmann Simulation of the Io's Plasma Environment with Adaptive Mesh and Particle Refinement

    NASA Astrophysics Data System (ADS)

    Lipatov, A. S.; Combi, M. R.

    2002-12-01

    The global dynamics of the ionized and neutral components in the environment of Io plays an important role in the interaction of Jupiter's corotating magnetospheric plasma with Io [Combi et al., 2002; 1998; Kabin et al., 2001]. The stationary simulation of this problem was done in the MHD [Combi et al., 1998; Linker et al, 1998; Kabin et al., 2001] and the electrodynamic [Saur et al., 1999] approaches. In this report, we develop a method of kinetic ion-neutral simulation, which is based on a multiscale adaptive mesh, particle and algorithm refinement. This method employs the fluid description for electrons whereas for ions the drift-kinetic and particle approaches are used. This method takes into account charge-exchange and photoionization processes. The first results of such simulation of the dynamics of ions in the Io's environment are discussed in this report. ~ M R Combi et al., J. Geophys. Res., 103, 9071, 1998. M R Combi, T I Gombosi, K Kabin, Atmospheres in the Solar System: Comparative\\ Aeronomy. Geophys. Monograph Series, 130, 151, 2002. K Kabin et al., Planetary and Space Sci., 49, 337, 2001. J A Linker et al., J. Geophys. Res., 103(E9), 19867, 1998. J Saur et al., J. Geophys. Res., 104, 25105, 1999.

  9. Adaptive and Efficient Computing for Subsurface Simulation within ParFlow

    SciTech Connect

    Tiedeman, H; Woodward, C S

    2010-11-16

    This project is concerned with the PF.WRF model as a means to enable more accurate predictions of wind fluctuations and subsurface storage. As developed at LLNL, PF.WRF couples a groundwater (subsurface) and surface water flow model (ParFlow) to a mesoscale atmospheric model (WRF, Weather Research and Forecasting Model). It was developed as a unique tool to address coupled water balance and wind energy questions that occur across traditionally separated research regimes of the atmosphere, land surface, and subsurface. PF.WRF is capable of simulating fluid, mass, and energy transport processes in groundwater, vadose zone, root zone, and land surface systems, including overland flow, and allows for the WRF model to both directly drive and respond to surface and subsurface hydrologic processes and conditions. The current PF.WRF model is constrained to have uniform spatial gridding below the land surface and matching areal grids with the WRF model at the land surface. There are often cases where it is advantageous for land surface, overland flow and subsurface models to have finer gridding than their atmospheric counterparts. Finer vertical discretization is also advantageous near the land surface (to properly capture feedbacks) yet many applications have a large vertical extent. However, the surface flow is strongly dependent on topography leading to a need for greater lateral resolution in some regions and the subsurface flow is tightly coupled to the atmospheric model near the surface leading to a need for finer vertical resolution. In addition, the interactions (e.g. rain) will be highly variable in space and time across the problem domain so an adaptive scheme is preferred to a static strategy to efficiently use computing and memory resources. As a result, this project focussed on algorithmic research required for development of an adaptive simulation capability in the PF.WRF system and its subsequent use in an application problem in the Central Valley of

  10. Translation to Portuguese and cultural adaptation of Food Allergy Quality of Life Questionnaire - Parent Form (FAQLQ-PF).

    PubMed

    Couto, M; Silva, D; Piedade, S; Borrego, Lm; Flokstra-de Blok, B; Dunn Galvin, A; Morais-Almeida, M

    2016-05-01

    Food allergy is a health problem with significant negative impact in Quality of Life (QoL). We aimed to translate into Portuguese and culturally adapt to our population the Food Allergy Quality of Life Questionnaire - Parent Form (FAQLQ-PF). Cross-cultural translation was performed according to guidelines. Linguistic validation consisted in 3 steps: forward translation, backward translation and comprehensibility testing. A consensual version was obtained and tested in parents of food allergic children by cognitive debriefing. Twelve questionnaires were fulfilled, all completed in ≤ 15 min. No comments, doubts or suggestions were posed, except for 2 parents regarding a question about the number of food their children had to avoid. Two gave special positive feedback about the utility of FAQLQ-PF. Changes have been included after this pre-test in accordance to doubts and suggestions of participants, and the Portuguese version is now able to be used in clinics and research.

  11. The Moist Side of Life--Some Classroom Activities in Biological Adaptation.

    ERIC Educational Resources Information Center

    Koch, Helmut

    There is a group of terrestrial crustaceans, the isopods or sowbugs, that spend their lives in the cool, damp and dark microhabitats beneath rocks, decaying logs, and leaf litter. Although these animals are well adapted to exploit these moist niches, they are obligated to live where they do because of their need for moisture and high humidity to…

  12. The Adaptive Basis of Psychosocial Acceleration: Comment on beyond Mental Health, Life History Strategies Articles

    ERIC Educational Resources Information Center

    Nettle, Daniel; Frankenhuis, Willem E.; Rickard, Ian J.

    2012-01-01

    Four of the articles published in this special section of "Developmental Psychology" build on and refine psychosocial acceleration theory. In this short commentary, we discuss some of the adaptive assumptions of psychosocial acceleration theory that have not received much attention. Psychosocial acceleration theory relies on the behavior of…

  13. Households, Migration and Labor Market Participation: The Adaptation of Mexicans to Life in the United States.

    ERIC Educational Resources Information Center

    Chavez, Leo R.

    1985-01-01

    The formation of extended family and other non-nuclear family households serves as an important mechanism in the adaptation of Mexican immigrants in San Diego. Different types of households are important at different times in the migration process, and immigration status influences the patterns of household variation. (KH)

  14. Toxic hydrogen sulfide and dark caves: life-history adaptations in a livebearing fish (Poecilia mexicana, Poeciliidae).

    PubMed

    Riesch, Rüdiger; Plath, Martin; Schlupp, Ingo

    2010-05-01

    Life-history traits are very sensitive to extreme environmental conditions, because resources that need to be invested in somatic maintenance cannot be invested in reproduction. Here we examined female life-history traits in the Mexican livebearing fish Poecilia mexicana from a variety of benign surface habitats, a creek with naturally occurring toxic hydrogen sulfide (H2S), a sulfidic cave, and a non-sulfidic cave. Previous studies revealed pronounced genetic and morphological divergence over very small geographic scales in this system despite the absence of physical barriers, suggesting that local adaptation to different combinations of two selection factors, toxicity (H2S) and darkness, is accompanied by very low rates of gene flow. Hence, we investigated life-history divergence between these populations in response to the selective pressures of darkness and/or toxicity. Our main results show that toxicity and darkness both select for (or impose constraints on) the same female trait dynamics: reduced fecundity and increased offspring size. Since reduced fecundity in the sulfur cave population was previously shown to be heritable, we discuss how divergent life-history evolution may promote further ecological divergence: for example, reduced fecundity and increased offspring autonomy are clearly beneficial in extreme environments, but fish with these traits are outcompeted in benign habitats.

  15. Numerical simulation of diffusion MRI signals using an adaptive time-stepping method

    NASA Astrophysics Data System (ADS)

    Li, Jing-Rebecca; Calhoun, Donna; Poupon, Cyril; Le Bihan, Denis

    2014-01-01

    The effect on the MRI signal of water diffusion in biological tissues in the presence of applied magnetic field gradient pulses can be modelled by a multiple compartment Bloch-Torrey partial differential equation. We present a method for the numerical solution of this equation by coupling a standard Cartesian spatial discretization with an adaptive time discretization. The time discretization is done using the explicit Runge-Kutta-Chebyshev method, which is more efficient than the forward Euler time discretization for diffusive-type problems. We use this approach to simulate the diffusion MRI signal from the extra-cylindrical compartment in a tissue model of the brain gray matter consisting of cylindrical and spherical cells and illustrate the effect of cell membrane permeability.

  16. High altitude simulation, substance P and airway rapidly adapting receptor activity in rabbits.

    PubMed

    Bhagat, R; Yasir, A; Vashisht, A; Kulshreshtha, R; Singh, S B; Ravi, K

    2011-09-15

    To investigate whether there is a change in airway rapidly adapting receptor (RAR) activity during high altitude exposure, rabbits were placed in a high altitude simulation chamber (barometric pressure, 429 mm Hg). With 12 h exposure, when there was pulmonary congestion, an increase in basal RAR activity was observed. With 36 h exposure, when there was alveolar edema, there was a further increase in basal RAR activity. In these backgrounds, there was an increase in the sensitivity of the RARs to substance P (SP). To assess whether there was an increase in lung SP level, neutral endopeptidase activity was determined which showed a decrease in low barometric pressure exposed groups. It is concluded that along with the SP released, pulmonary congestion and edema produced, respectively by different durations of low barometric pressure exposure cause a progressive increase in RAR activity which may account for the respiratory symptoms reported in climbers who are unacclimatized.

  17. Optical Cluster-Finding with an Adaptive Matched-Filter Technique: Algorithm and Comparison with Simulations

    SciTech Connect

    Dong, Feng; Pierpaoli, Elena; Gunn, James E.; Wechsler, Risa H.

    2007-10-29

    We present a modified adaptive matched filter algorithm designed to identify clusters of galaxies in wide-field imaging surveys such as the Sloan Digital Sky Survey. The cluster-finding technique is fully adaptive to imaging surveys with spectroscopic coverage, multicolor photometric redshifts, no redshift information at all, and any combination of these within one survey. It works with high efficiency in multi-band imaging surveys where photometric redshifts can be estimated with well-understood error distributions. Tests of the algorithm on realistic mock SDSS catalogs suggest that the detected sample is {approx} 85% complete and over 90% pure for clusters with masses above 1.0 x 10{sup 14}h{sup -1} M and redshifts up to z = 0.45. The errors of estimated cluster redshifts from maximum likelihood method are shown to be small (typically less that 0.01) over the whole redshift range with photometric redshift errors typical of those found in the Sloan survey. Inside the spherical radius corresponding to a galaxy overdensity of {Delta} = 200, we find the derived cluster richness {Lambda}{sub 200} a roughly linear indicator of its virial mass M{sub 200}, which well recovers the relation between total luminosity and cluster mass of the input simulation.

  18. Verification and validation of impinging round jet simulations using an adaptive FEM

    NASA Astrophysics Data System (ADS)

    Pelletier, Dominique; Turgeon, Éric; Tremblay, Dominique

    2004-03-01

    This paper illustrates the use of an adaptive finite element method as a means of achieving verification of codes and simulations of impinging round jets, that is obtaining numerical predictions with controlled accuracy. Validation of these grid-independent solution is then performed by comparing predictions to measurements. We adopt the standard and accepted definitions of verification and validation (Technical Report AIAA-G-077-1998, American Institute of Aeronautics and Astronautics, 1998; Verification and Validation in Computational Science and Engineering. Hermosa Publishers: Albuquerque, NM, 1998). Mesh adaptation is used to perform the systematic and rigorous grid refinement studies required for both verification and validation in CFD. This ensures that discrepancies observed between predictions and measurements are due to deficiencies in the mathematical model of the flow. Issues in verification and validation are discussed. The paper presents an example of code verification by the method of manufactured solution. Examples of successful and unsuccessful validation for laminar and turbulent impinging jets show that agreement with experiments is achieved only with a good mathematical model of the flow physics combined with accurate numerical solution of the differential equations. The paper emphasizes good CFD practice to systematically achieve verification so that validation studies are always performed on solid grounds.

  19. Clustering of tethered satellite system simulation data by an adaptive neuro-fuzzy algorithm

    NASA Technical Reports Server (NTRS)

    Mitra, Sunanda; Pemmaraju, Surya

    1992-01-01

    Recent developments in neuro-fuzzy systems indicate that the concepts of adaptive pattern recognition, when used to identify appropriate control actions corresponding to clusters of patterns representing system states in dynamic nonlinear control systems, may result in innovative designs. A modular, unsupervised neural network architecture, in which fuzzy learning rules have been embedded is used for on-line identification of similar states. The architecture and control rules involved in Adaptive Fuzzy Leader Clustering (AFLC) allow this system to be incorporated in control systems for identification of system states corresponding to specific control actions. We have used this algorithm to cluster the simulation data of Tethered Satellite System (TSS) to estimate the range of delta voltages necessary to maintain the desired length rate of the tether. The AFLC algorithm is capable of on-line estimation of the appropriate control voltages from the corresponding length error and length rate error without a priori knowledge of their membership functions and familarity with the behavior of the Tethered Satellite System.

  20. Numerical simulation studies for the first-light adaptive optics system of the Large Binocular Telescope

    NASA Astrophysics Data System (ADS)

    Carbillet, Marcel; Riccardi, Armando; Esposito, Simone

    2004-10-01

    We present our latest results concerning the simulation studies performed for the first-light adaptive optics (AO) system of the Large Binocular Telescope (LBT), namely WLBT. After a brief description of the "raw" performance evaluation results, in terms of Strehl ratios attained in the various considered bands (from V to K), we focus on the "scientific" performance that will be obtained when considering the subsequent instrumentation that will benefit from the correction given by the AO system WLBT and the adaptive secondary mirrors LBT 672. In particular, we discuss the performance of the coupling with the instrument LUCIFER, working at near-infrared bands, in terms of signal-to-noise values and limiting magnitudes, and in both the cases of spectroscopy and photometric detection. We also give the encircled energies that are expected in the visible bands, result relevant in one hand for the instrument PEPSI, and in other hand for the "technical viewer" that will be on board the WLBT system itself.

  1. Design and simulation of adaptive optics controller based on mixed sensitivity H∞ control

    NASA Astrophysics Data System (ADS)

    Song, Dingan; Li, Xinyang; Peng, Zhenming

    2016-10-01

    Optical systems such as telescopes are very complex, and their model usually with the uncertainty. To deal with the uncertainty of adaptive optics system and improve system robust stability, the mixed sensitivity H-infinity control has been introduced to design system controller. In order to testify the validity, wavefront aberration correction capability, as well as the robust stability, has been compared between the mixed sensitivity H-infinity controller and the classic integral controller. The computer simulation results demonstrate that the system with the mixed sensitivity H-infinity controller, while can't guarantee a better correction performance, has greater robust stability than the one with the classic integral controller. That is to say, greater robust stability is achieved at the expense of the correction capability in the system with H-infinity controller. Moreover, the greater the uncertainty is, the more proceeds the mixed sensitivity H-infinity controller will produce. It proves the efficiency of the mixed sensitivity H-infinity controller in dealing with the uncertainty of adaptive optics system.

  2. Application of adaptive hierarchical sparse grid collocation to the uncertainty quantification of nuclear reactor simulators

    SciTech Connect

    Yankov, A.; Downar, T.

    2013-07-01

    Recent efforts in the application of uncertainty quantification to nuclear systems have utilized methods based on generalized perturbation theory and stochastic sampling. While these methods have proven to be effective they both have major drawbacks that may impede further progress. A relatively new approach based on spectral elements for uncertainty quantification is applied in this paper to several problems in reactor simulation. Spectral methods based on collocation attempt to couple the approximation free nature of stochastic sampling methods with the determinism of generalized perturbation theory. The specific spectral method used in this paper employs both the Smolyak algorithm and adaptivity by using Newton-Cotes collocation points along with linear hat basis functions. Using this approach, a surrogate model for the outputs of a computer code is constructed hierarchically by adaptively refining the collocation grid until the interpolant is converged to a user-defined threshold. The method inherently fits into the framework of parallel computing and allows for the extraction of meaningful statistics and data that are not within reach of stochastic sampling and generalized perturbation theory. This paper aims to demonstrate the advantages of spectral methods-especially when compared to current methods used in reactor physics for uncertainty quantification-and to illustrate their full potential. (authors)

  3. Thickness-based adaptive mesh refinement methods for multi-phase flow simulations with thin regions

    SciTech Connect

    Chen, Xiaodong; Yang, Vigor

    2014-07-15

    In numerical simulations of multi-scale, multi-phase flows, grid refinement is required to resolve regions with small scales. A notable example is liquid-jet atomization and subsequent droplet dynamics. It is essential to characterize the detailed flow physics with variable length scales with high fidelity, in order to elucidate the underlying mechanisms. In this paper, two thickness-based mesh refinement schemes are developed based on distance- and topology-oriented criteria for thin regions with confining wall/plane of symmetry and in any situation, respectively. Both techniques are implemented in a general framework with a volume-of-fluid formulation and an adaptive-mesh-refinement capability. The distance-oriented technique compares against a critical value, the ratio of an interfacial cell size to the distance between the mass center of the cell and a reference plane. The topology-oriented technique is developed from digital topology theories to handle more general conditions. The requirement for interfacial mesh refinement can be detected swiftly, without the need of thickness information, equation solving, variable averaging or mesh repairing. The mesh refinement level increases smoothly on demand in thin regions. The schemes have been verified and validated against several benchmark cases to demonstrate their effectiveness and robustness. These include the dynamics of colliding droplets, droplet motions in a microchannel, and atomization of liquid impinging jets. Overall, the thickness-based refinement technique provides highly adaptive meshes for problems with thin regions in an efficient and fully automatic manner.

  4. Test Population Selection from Weibull-Based, Monte Carlo Simulations of Fatigue Life

    NASA Technical Reports Server (NTRS)

    Vlcek, Brian L.; Zaretsky, Erwin V.; Hendricks, Robert C.

    2012-01-01

    Fatigue life is probabilistic and not deterministic. Experimentally establishing the fatigue life of materials, components, and systems is both time consuming and costly. As a result, conclusions regarding fatigue life are often inferred from a statistically insufficient number of physical tests. A proposed methodology for comparing life results as a function of variability due to Weibull parameters, variability between successive trials, and variability due to size of the experimental population is presented. Using Monte Carlo simulation of randomly selected lives from a large Weibull distribution, the variation in the L10 fatigue life of aluminum alloy AL6061 rotating rod fatigue tests was determined as a function of population size. These results were compared to the L10 fatigue lives of small (10 each) populations from AL2024, AL7075 and AL6061. For aluminum alloy AL6061, a simple algebraic relationship was established for the upper and lower L10 fatigue life limits as a function of the number of specimens failed. For most engineering applications where less than 30 percent variability can be tolerated in the maximum and minimum values, at least 30 to 35 test samples are necessary. The variability of test results based on small sample sizes can be greater than actual differences, if any, that exists between materials and can result in erroneous conclusions. The fatigue life of AL2024 is statistically longer than AL6061 and AL7075. However, there is no statistical difference between the fatigue lives of AL6061 and AL7075 even though AL7075 had a fatigue life 30 percent greater than AL6061.

  5. Test Population Selection from Weibull-Based, Monte Carlo Simulations of Fatigue Life

    NASA Technical Reports Server (NTRS)

    Vlcek, Brian L.; Zaretsky, Erwin V.; Hendricks, Robert C.

    2008-01-01

    Fatigue life is probabilistic and not deterministic. Experimentally establishing the fatigue life of materials, components, and systems is both time consuming and costly. As a result, conclusions regarding fatigue life are often inferred from a statistically insufficient number of physical tests. A proposed methodology for comparing life results as a function of variability due to Weibull parameters, variability between successive trials, and variability due to size of the experimental population is presented. Using Monte Carlo simulation of randomly selected lives from a large Weibull distribution, the variation in the L10 fatigue life of aluminum alloy AL6061 rotating rod fatigue tests was determined as a function of population size. These results were compared to the L10 fatigue lives of small (10 each) populations from AL2024, AL7075 and AL6061. For aluminum alloy AL6061, a simple algebraic relationship was established for the upper and lower L10 fatigue life limits as a function of the number of specimens failed. For most engineering applications where less than 30 percent variability can be tolerated in the maximum and minimum values, at least 30 to 35 test samples are necessary. The variability of test results based on small sample sizes can be greater than actual differences, if any, that exists between materials and can result in erroneous conclusions. The fatigue life of AL2024 is statistically longer than AL6061 and AL7075. However, there is no statistical difference between the fatigue lives of AL6061 and AL7075 even though AL7075 had a fatigue life 30 percent greater than AL6061.

  6. Tool life modeling and computer simulation of tool wear when nickel-based material turning

    NASA Astrophysics Data System (ADS)

    Zebala, W.

    2016-09-01

    Paper presents some tool life investigations, concerning modeling and simulation of tool wear when turning a difficult-to-cut material like nickel based sintered powder workpiece. A cutting tool made of CBN has its special geometry. The workpiece in the form of disc is an aircraft engine part. The aim of researches is to optimize the cutting data for the purpose to decrease the tool wear and improve the machined surface roughness.

  7. Direct numerical simulations of particle-laden density currents with adaptive, discontinuous finite elements

    NASA Astrophysics Data System (ADS)

    Parkinson, S. D.; Hill, J.; Piggott, M. D.; Allison, P. A.

    2014-05-01

    High resolution direct numerical simulations (DNS) are an important tool for the detailed analysis of turbidity current dynamics. Models that resolve the vertical structure and turbulence of the flow are typically based upon the Navier-Stokes equations. Two-dimensional simulations are known to produce unrealistic cohesive vortices that are not representative of the real three-dimensional physics. The effect of this phenomena is particularly apparent in the later stages of flow propagation. The ideal solution to this problem is to run the simulation in three dimensions but this is computationally expensive. This paper presents a novel finite-element (FE) DNS turbidity current model that has been built within Fluidity, an open source, general purpose, computational fluid dynamics code. The model is validated through re-creation of a lock release density current at a Grashof number of 5 × 106 in two, and three-dimensions. Validation of the model considers the flow energy budget, sedimentation rate, head speed, wall normal velocity profiles and the final deposit. Conservation of energy in particular is found to be a good metric for measuring mesh performance in capturing the range of dynamics. FE models scale well over many thousands of processors and do not impose restrictions on domain shape, but they are computationally expensive. Use of discontinuous discretisations and adaptive unstructured meshing technologies, which reduce the required element count by approximately two orders of magnitude, results in high resolution DNS models of turbidity currents at a fraction of the cost of traditional FE models. The benefits of this technique will enable simulation of turbidity currents in complex and large domains where DNS modelling was previously unachievable.

  8. Adaptive Planning: Understanding Organizational Workload to Capability/ Capacity through Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Hase, Chris

    2010-01-01

    In August 2003, the Secretary of Defense (SECDEF) established the Adaptive Planning (AP) initiative [1] with an objective of reducing the time necessary to develop and revise Combatant Commander (COCOM) contingency plans and increase SECDEF plan visibility. In addition to reducing the traditional plan development timeline from twenty-four months to less than twelve months (with a goal of six months)[2], AP increased plan visibility to Department of Defense (DoD) leadership through In-Progress Reviews (IPRs). The IPR process, as well as the increased number of campaign and contingency plans COCOMs had to develop, increased the workload while the number of planners remained fixed. Several efforts from collaborative planning tools to streamlined processes were initiated to compensate for the increased workload enabling COCOMS to better meet shorter planning timelines. This paper examines the Joint Strategic Capabilities Plan (JSCP) directed contingency planning and staffing requirements assigned to a combatant commander staff through the lens of modeling and simulation. The dynamics of developing a COCOM plan are captured with an ExtendSim [3] simulation. The resulting analysis provides a quantifiable means by which to measure a combatant commander staffs workload associated with development and staffing JSCP [4] directed contingency plans with COCOM capability/capacity. Modeling and simulation bring significant opportunities in measuring the sensitivity of key variables in the assessment of workload to capability/capacity analysis. Gaining an understanding of the relationship between plan complexity, number of plans, planning processes, and number of planners with time required for plan development provides valuable information to DoD leadership. Through modeling and simulation AP leadership can gain greater insight in making key decisions on knowing where to best allocate scarce resources in an effort to meet DoD planning objectives.

  9. Adaptive change in self-concept and well-being during conjugal loss in later life.

    PubMed

    Montpetit, Mignon A; Bergeman, C S; Bisconti, Toni L; Rausch, Joseph R

    2006-01-01

    The present study examines the association between the self-concept and adaptation to conjugal loss; the primary aim was to explore whether those individuals high in self-esteem, environmental mastery, and optimism have more adaptive resources with which to ameliorate the detrimental sequelae of bereavement. Analyses were conducted on data collected from 58 widows every four months over a two-year period. One goal of the research was to explore the adequacy of the theoretically chosen operational definition of the self-concept; another goal was to analyze how changes in the level of self-concept components correlated with changes in levels of depression, health, and grief resolution as individuals adjusted to their losses. Analyses revealed that trajectories of depression and grief resolution were more highly related than health to changes in self-concept.

  10. Immune adjuvants in early life: targeting the innate immune system to overcome impaired adaptive response.

    PubMed

    de Brito, Cyro Alves; Goldoni, Adriana Letícia; Sato, Maria Notomi

    2009-09-01

    The neonatal phase is a transitory period characterized by an absence of memory cells, favoring a slow adaptive response prone to tolerance effects and the development of Th2-type responses. However, when appropriately stimulated, neonates may achieve an immune response comparable with adult counterparts. One strategy to stimulate the immunological response of neonates or children in early infancy has been to explore natural or synthetic ligands of cell receptors to stimulate innate immunity. The use of adjuvants for activating different cell receptors may be the key to enhancing neonatal adaptive immunity. This review highlights recent advances in the emerging field of molecular adjuvants of innate immune response and their implications for the development of immunotherapies, with particular focus on the neonatal period.

  11. The life closure scale: additional psychometric testing of a tool to measure psychological adaptation in death and dying.

    PubMed

    Dobratz, Marjorie C

    2004-02-01

    The purpose of this study was to conduct additional psychometric testing on an instrument designed to measure psychological adaptation in end-of-life populations across a wide spectrum of terminal illnesses. A sample of 20 participants completed initial testing of the Life Closure Scale (LCS); however, its usefulness was limited by the small sample size. A larger sample of 113 home hospice individuals who met established criteria and who gave informed consent completed the 27-item LCS for additional psychometric testing. Cronbach's alphas and correlation coefficients were computed, and factor analysis was conducted to establish internal consistency reliability, theoretical clarity, and criterion-related validity. The number of scale items was reduced to 20, with a total alpha of.87. Cronbach's alphas for the two subscales were.80 (self-reconciled) and.82 (self-restructuring). Item-total correlations for the subscales ranged from a low of.37 to a high of.68, with confirmatory factor analysis yielding two loadings. These findings lend credence to the usefulness of the LCS in measuring psychological adaptation in dying persons.

  12. Human cooperation shows the distinctive signatures of adaptations to small-scale social life.

    PubMed

    Tooby, John; Cosmides, Leda

    2016-01-01

    The properties of individual carbon atoms allow them to chain into complex molecules of immense length. They are not limited to structures involving only a few atoms. The design features of our evolved neural adaptations appear similarly extensible. Individuals with forager brains can link themselves together into unprecedentedly large cooperative structures without the need for large group-beneficial modifications to evolved human design. Roles need only be intelligible to our social program logic, and judged better than alternatives.

  13. A Case-Study for Life-Long Learning and Adaptation in Cooperative Robot Teams

    SciTech Connect

    Parker, L.E.

    1999-09-19

    While considerable progress has been made in recent years toward the development of multi-robot teams, much work remains to be done before these teams are used widely in real-world applications. Two particular needs toward this end are the development of mechanisms that enable robot teams to generate cooperative behaviors on their own, and the development of techniques that allow these teams to autonomously adapt their behavior over time as the environment or the robot team changes. This paper proposes the use of the Cooperative Multi-Robot Observation of Multiple Moving Targets (CMOMMT) application as a rich domain for studying the issues of multi-robot learning and adaptation. After discussing the need for learning and adaptation in multi-robot teams, this paper describes the CMOMMT application and its relevance to multi-robot learning. We discuss the results of the previously- developed, hand-generated algorithm for CMOMMT and the potential for learning that was discovered from the hand-generated approach. We then describe the early work that has been done (by us and others) to generate multi- robot learning techniques for the CMOMMT application, as well as our ongoing research to develop approaches that give performance as good, or better, than the hand-generated approach. The ultimate goal of this research is to develop techniques for multi-robot learning and adaptation in the CMOMMT application domain that will generalize to cooperative robot applications in other domains, thus making the practical use of multi-robot teams in a wide variety of real-world applications much closer to reality.

  14. Pilot Inventory Complex Adaptive System (PICAS): An Artificial Life Approach to Managing Pilot Retention.

    DTIC Science & Technology

    1999-03-01

    statistics also provides a means by which to compare different executions of the model. As with any simulation, multiple runs produce distributional...weight scroll bar and a new fitness function is produced. This new fitness function is compared to the pilot-agent’s current fitness function and used to...execution of the simulation. This method allows the user to view model results and compare different model runs. The statistics displayed are those

  15. Polar bears exhibit genome-wide signatures of bioenergetic adaptation to life in the Arctic environment

    USGS Publications Warehouse

    Welch, Andreanna J.; Bedoya-Reina, Oscar C.; Carretero-Paulet, Lorenzo; Miller, Webb; Rode, Karyn D.; Lindqvist, Charlotte

    2014-01-01

    Polar bears (Ursus maritimus) face extremely cold temperatures and periods of fasting, which might result in more severe energetic challenges than those experienced by their sister species, the brown bear (U. arctos). We have examined the mitochondrial and nuclear genomes of polar and brown bears to investigate if polar bears demonstrate lineage-specific signals of molecular adaptation in genes associated with cellular respiration/energy production. We observed increased evolutionary rates in the mitochondrial cytochrome c oxidase I gene in polar but not brown bears. An amino acid substitution occurred near the interaction site with a nuclear-encoded subunit of the cytochrome c oxidase complex, and was predicted to lead to a functional change, although the significance of this remains unclear. The nuclear genomes of brown and polar bears demonstrate different adaptations related to cellular respiration. Analyses of the genomes of brown bears exhibited substitutions that may alter the function of proteins that regulate glucose uptake, which could be beneficial when feeding on carbohydrate-dominated diets during hyperphagia, followed by fasting during hibernation. In polar bears, genes demonstrating signatures of functional divergence and those potentially under positive selection were enriched in functions related to production of nitric oxide, which can regulate energy production in several different ways. This suggests that polar bears may be able to fine-tune intracellular levels of nitric oxide as an adaptive response to control trade-offs between energy production in the form of ATP versus generation of heat (thermogenesis).

  16. Polar bears exhibit genome-wide signatures of bioenergetic adaptation to life in the arctic environment.

    PubMed

    Welch, Andreanna J; Bedoya-Reina, Oscar C; Carretero-Paulet, Lorenzo; Miller, Webb; Rode, Karyn D; Lindqvist, Charlotte

    2014-02-01

    Polar bears (Ursus maritimus) face extremely cold temperatures and periods of fasting, which might result in more severe energetic challenges than those experienced by their sister species, the brown bear (U. arctos). We have examined the mitochondrial and nuclear genomes of polar and brown bears to investigate whether polar bears demonstrate lineage-specific signals of molecular adaptation in genes associated with cellular respiration/energy production. We observed increased evolutionary rates in the mitochondrial cytochrome c oxidase I gene in polar but not brown bears. An amino acid substitution occurred near the interaction site with a nuclear-encoded subunit of the cytochrome c oxidase complex and was predicted to lead to a functional change, although the significance of this remains unclear. The nuclear genomes of brown and polar bears demonstrate different adaptations related to cellular respiration. Analyses of the genomes of brown bears exhibited substitutions that may alter the function of proteins that regulate glucose uptake, which could be beneficial when feeding on carbohydrate-dominated diets during hyperphagia, followed by fasting during hibernation. In polar bears, genes demonstrating signatures of functional divergence and those potentially under positive selection were enriched in functions related to production of nitric oxide (NO), which can regulate energy production in several different ways. This suggests that polar bears may be able to fine-tune intracellular levels of NO as an adaptive response to control trade-offs between energy production in the form of adenosine triphosphate versus generation of heat (thermogenesis).

  17. The molecular signal for the adaptation to cold temperature during early life on Earth.

    PubMed

    Groussin, Mathieu; Boussau, Bastien; Charles, Sandrine; Blanquart, Samuel; Gouy, Manolo

    2013-10-23

    Several lines of evidence such as the basal location of thermophilic lineages in large-scale phylogenetic trees and the ancestral sequence reconstruction of single enzymes or large protein concatenations support the conclusion that the ancestors of the bacterial and archaeal domains were thermophilic organisms which were adapted to hot environments during the early stages of the Earth. A parsimonious reasoning would therefore suggest that the last universal common ancestor (LUCA) was also thermophilic. Various authors have used branch-wise non-homogeneous evolutionary models that better capture the variation of molecular compositions among lineages to accurately reconstruct the ancestral G + C contents of ribosomal RNAs and the ancestral amino acid composition of highly conserved proteins. They confirmed the thermophilic nature of the ancestors of Bacteria and Archaea but concluded that LUCA, their last common ancestor, was a mesophilic organism having a moderate optimal growth temperature. In this letter, we investigate the unknown nature of the phylogenetic signal that informs ancestral sequence reconstruction to support this non-parsimonious scenario. We find that rate variation across sites of molecular sequences provides information at different time scales by recording the oldest adaptation to temperature in slow-evolving regions and subsequent adaptations in fast-evolving ones.

  18. Polar Bears Exhibit Genome-Wide Signatures of Bioenergetic Adaptation to Life in the Arctic Environment

    PubMed Central

    Welch, Andreanna J.; Carretero-Paulet, Lorenzo; Miller, Webb; Rode, Karyn D.; Lindqvist, Charlotte

    2014-01-01

    Polar bears (Ursus maritimus) face extremely cold temperatures and periods of fasting, which might result in more severe energetic challenges than those experienced by their sister species, the brown bear (U. arctos). We have examined the mitochondrial and nuclear genomes of polar and brown bears to investigate whether polar bears demonstrate lineage-specific signals of molecular adaptation in genes associated with cellular respiration/energy production. We observed increased evolutionary rates in the mitochondrial cytochrome c oxidase I gene in polar but not brown bears. An amino acid substitution occurred near the interaction site with a nuclear-encoded subunit of the cytochrome c oxidase complex and was predicted to lead to a functional change, although the significance of this remains unclear. The nuclear genomes of brown and polar bears demonstrate different adaptations related to cellular respiration. Analyses of the genomes of brown bears exhibited substitutions that may alter the function of proteins that regulate glucose uptake, which could be beneficial when feeding on carbohydrate-dominated diets during hyperphagia, followed by fasting during hibernation. In polar bears, genes demonstrating signatures of functional divergence and those potentially under positive selection were enriched in functions related to production of nitric oxide (NO), which can regulate energy production in several different ways. This suggests that polar bears may be able to fine-tune intracellular levels of NO as an adaptive response to control trade-offs between energy production in the form of adenosine triphosphate versus generation of heat (thermogenesis). PMID:24504087

  19. Preventing Adolescent Substance Use Through an Evidence-Based Program: Effects of the Italian Adaptation of Life Skills Training.

    PubMed

    Velasco, Veronica; Griffin, Kenneth W; Botvin, Gilbert J

    2017-03-28

    Evidence-based preventive interventions for adolescent substance use, violence, and mental health issues are increasingly being adapted and disseminated internationally. In the present paper, we report the results of an effectiveness study that was part of a comprehensive initiative by a coalition of health promotion organizations in the Lombardy region of Italy to select, culturally adapt, implement, evaluate, and sustain an evidence-based drug abuse prevention program developed in the USA. Findings are presented from a large-scale effectiveness study of the Life Skills Training prevention program among over 3000 students attending 55 middle schools in Italy. The prevention program taught drug refusal skills, antidrug norms, personal self-management skills, and general social skills. Relative to comparison group students, students who received the prevention program were less likely to initiate smoking at the post-test and 2-year follow-up, and less likely to initiate weekly drunkenness at the 1-year follow-up. The program had direct positive effects on several cognitive, attitudinal, and skill variables believed to play a protective role in adolescent substance use. The findings from this study show that a drug abuse prevention program originally designed for adolescents in the USA is effective in a sample of Italian youth when a rigorous and systematic approach to cultural adaptation is followed that incorporates the input of multiple stakeholders.

  20. Translation, cultural adaptation, and validation of the American Skindex-29 quality of life index*

    PubMed Central

    de Paula, Henrique Ribeiro; Haddad, Alessandra; Weiss, Mariana Alves; Dini, Gal Moreira; Ferreira, Lydia Masako

    2014-01-01

    BACKGROUND Measuring the quality of life measure of patients with dermatologic diseases is an important concern. The instruments to evaluate it are commonly originally written in English and need to be translated and validated to be used in different cultures. OBJECTIVE The purpose of this paper is to translate and validate the Skindex-29 questionnaire to Brazilian Portuguese to be used in our country as a quality of life assessment instrument in dermatologic patients. METHODS The first step was the translation from English to Brazilian Portuguese and the back-translation by two native speakers. The translated version was then used for the second step, when three questionnaires were applied to 75 patients (43 of whom were classified as lightly affected and 32 as heavily affected by their dermatologic conditions): an identification questionnaire, the translated version of Skindex-29, and the Brazilian Portuguese version of Dermatologic Life Quality Index (DLQI). Additionally, the generic questionnaire Short Form 36 (SF-36) was applied to 41 of these patients. The last step to evaluate reproducibility was repeating the Skindex-29 questionnaire by the same researcher one week later in 44 patients. RESULTS Reliability was observed in global Skindex-29 scale (α=0.934), and its domains emotions (α=0.926), symptoms (α=0,702), and psycosocial functioning (α=0.860). The reproducibility showed high intraclass correlations. High intra class correlations was observed, thus validating reliability. CONCLUSIONS The Skindex-29 quality of life questionnaire was properly translated and validated to Brazilian Portuguese. PMID:25054747

  1. Translation, Adaptation and Initial Validation of Food Allergy Quality of Life Questionnaire: Child form in Greek.

    PubMed

    Morou, Zoe; Lyrakos, Georgios N; Papadopoulos, Nikolaos G; Douladiris, Nikolaos; Tatsioni, Athina; Dimoliatis, Ioannis D K

    2016-06-23

    The aim of the study is to determine the reliability and validity of the Greek version of the Food Allergy Quality of life Questionnaire-Child Form (FAQLQ-CF). After linguistic validation, the Greek FAQLQ-CF, Food Allergy Independent Measure (FAIM) and Pediatric Quality of Life Inventory (PedsQL™) were used by a physician to interview children diagnosed with food allergy and aged 8-12 via telephone. Cronbach's alpha was used to evaluate reliability, and factor analysis to assess construct validity. The correlation between FAQLQ-CF and FAIM was moderate (rho=0.509, P<0.001) and internal consistency was strong (Cronbach's alpha 0.905). FAQLQ-CF discriminated well each question's contribution to children's quality of life deterioration (32-80%), each child's quality of life (17-89%), children differing in doing things with others (total score 3.55 vs 2.57, difference =0.98 > minimal clinical importance difference = 0.5; P<0.001), but not children differing in reporting anaphylaxis. The total FAQLQ-CF score correlated with the total PedsQL™ score and with the score of one of PedsQL™ subscales, demonstrating convergent validity. Factor analysis uncovered an underlying structure of four factors, explaining 50% of the variance. We can conclude that Greek FAQLQ-CF is a reliable, valid, discriminant tool for interviewing food allergic children aged 8-12, detecting those in need for immediate care.

  2. The consequences of early-life adversity: neurobiological, behavioural and epigenetic adaptations.

    PubMed

    Maccari, S; Krugers, H J; Morley-Fletcher, S; Szyf, M; Brunton, P J

    2014-10-01

    During the perinatal period, the brain is particularly sensitive to remodelling by environmental factors. Adverse early-life experiences, such as stress exposure or suboptimal maternal care, can have long-lasting detrimental consequences for an individual. This phenomenon is often referred to as 'early-life programming' and is associated with an increased risk of disease. Typically, rodents exposed to prenatal stress or postnatal maternal deprivation display enhanced neuroendocrine responses to stress, increased levels of anxiety and depressive-like behaviours, and cognitive impairments. Some of the phenotypes observed in these models of early-life adversity are likely to share common neurobiological mechanisms. For example, there is evidence for impaired glucocorticoid negative-feedback control of the hypothalamic-pituitary-adrenal axis, altered glutamate neurotransmission and reduced hippocampal neurogenesis in both prenatally stressed rats and rats that experienced deficient maternal care. The possible mechanisms through which maternal stress during pregnancy may be transmitted to the offspring are reviewed, with special consideration given to altered maternal behaviour postpartum. We also discuss what is known about the neurobiological and epigenetic mechanisms that underpin early-life programming of the neonatal brain in the first generation and subsequent generations, with a view to abrogating programming effects and potentially identifying new therapeutic targets for the treatment of stress-related disorders and cognitive impairment.

  3. Design, development, and performance of an adapter for simulation of ocular melanoma patients in supine position for proton beam therapy

    NASA Astrophysics Data System (ADS)

    Daftari, I.; Phillips, T. L.

    2003-06-01

    A patient assembly adapter system for ocular melanoma patient simulation was developed and its performance evaluated. The aim for the construction of the apparatus was to simulate the patients in supine position using a commercial x-ray simulator. The apparatus consists of a base plate, head immobilization holder, patient assembly system that includes fixation light and collimator system. The reproducibility of the repeated fixation was initially tested with a head phantom. Simulation and verification films were studied for seven consecutive patients treated with proton beam therapy. Patient's simulation was performed in a supine position using a dental fixation bite block and a thermoplastic head mask immobilization device with a patient adapter system. Two orthogonal x rays were used to obtain the x, y, and z coordinates of sutured tantalum rings for treatment planning with the EYEPLAN software. The verification films were obtained in treatment position with the fixation light along the central axis of the eye. The results indicate good agreement within 0.5 mm deviations. The results of this investigation showed that the same planning accuracy could be achieved by performing simulation using the adapter described above with a patient in the supine position as that obtained by performing simulation with the patient in the seated, treatment position. The adapter can also be attached to the head of the chair for simulating in the seated position using a fixed x-ray unit. This has three advantages: (1) this will save radiation therapists time; (2) it eliminates the need for arranging access to the treatment room, thus avoiding potential conflicts in treatment room usage; and (3) it allows the use of a commercial simulator.

  4. Hindlimb musculature of the largest living rodent Hydrochoerus hydrochaeris (Caviomorpha): Adaptations to semiaquatic and terrestrial styles of life.

    PubMed

    García-Esponda, César M; Candela, Adriana M

    2016-03-01

    The caviomorph species Hydrochoerus hydrochaeris (Cavioidea), or capybara, is the largest living rodent. This species is widely distributed, from northern South America to Uruguay and eastern Argentina, inhabiting in a wide variety of densely vegetated lowlands habitats in the proximity of water. Hydrochoerus hydrochaeris not only runs with agility, like other members of the Cavioidea, but it can also swim and dive easily. For these reasons, it has been classified as a cursorial as well as semiaquatic species. However, comprehensive anatomical descriptions of the osteology and myology of the capybara are not available in the literature and analyses on its swimming abilities are still required. We hypothesize that some of the characters of the hindlimb of H. hydrochaeris could reveal a unique morphological arrangement associated with swimming abilities. In this study, an anatomical description of the hindlimb musculature of H. hydrochaeris, and a discussion of the possible functional significance of the main muscles is provided. In addition, we explore the evolution of some myological and osteological characters of the capybara in the context of the cavioids. We concluded that most of the muscular and osteological features of the hindlimb of H. hydrochaeris are neither adaptations to a specialized cursoriality, nor major modifications for an aquatic mode of life. Hydrochoerus hydrochaeris share several features with other cavioids, being a generalized cursorial species in the context of this clade. However, it shows some adaptations of the hindlimb for enhancing propulsion through water, of which the most notable seems to be the shortening of the leg, short tendons of most muscles of the leg, and a well-developed soleus muscle. These adaptations to a semiaquatic mode of life could have been acquired during the most recent evolutionary history of the hydrochoerids.

  5. Study of the psychological adaptation of the crew during a 135 days space simulation.

    PubMed

    Rosnet, E; Cazes, G; Vinokhodova, A

    1998-01-01

    The purpose of this study is to examine human adaptation of a three members' crew during a 135 days MIR flight simulation and to compare and validate psychological methods for monitoring and support in flight. The main findings showed that isolation was not a key factor for the subjects who were more concerned by recreational activities, family, and work. The individual reactions to stress of the crew members were to project their problems on the others. These reactions had some consequences upon the group: Although the three subjects developed a weak tendency to "group think", one of the crew members was considered as less integrated to the group by the other two subjects, who, however, acted to protect (successfully) the general cohesion and mood of the crew. From a methodological point of view, baseline data predicted the difficulties that occurred for one of the crew member. Both quantitative and qualitative tools were adequate, although qualitative tests gave a closer approach to the actual situation that developed during the simulation.

  6. Advances in Rotor Performance and Turbulent Wake Simulation Using DES and Adaptive Mesh Refinement

    NASA Technical Reports Server (NTRS)

    Chaderjian, Neal M.

    2012-01-01

    Time-dependent Navier-Stokes simulations have been carried out for a rigid V22 rotor in hover, and a flexible UH-60A rotor in forward flight. Emphasis is placed on understanding and characterizing the effects of high-order spatial differencing, grid resolution, and Spalart-Allmaras (SA) detached eddy simulation (DES) in predicting the rotor figure of merit (FM) and resolving the turbulent rotor wake. The FM was accurately predicted within experimental error using SA-DES. Moreover, a new adaptive mesh refinement (AMR) procedure revealed a complex and more realistic turbulent rotor wake, including the formation of turbulent structures resembling vortical worms. Time-dependent flow visualization played a crucial role in understanding the physical mechanisms involved in these complex viscous flows. The predicted vortex core growth with wake age was in good agreement with experiment. High-resolution wakes for the UH-60A in forward flight exhibited complex turbulent interactions and turbulent worms, similar to the V22. The normal force and pitching moment coefficients were in good agreement with flight-test data.

  7. An Adaptive Multigrid Algorithm for Simulating Solid Tumor Growth Using Mixture Models

    PubMed Central

    Wise, S.M.; Lowengrub, J.S.; Cristini, V.

    2010-01-01

    In this paper we give the details of the numerical solution of a three-dimensional multispecies diffuse interface model of tumor growth, which was derived in (Wise et al., J. Theor. Biol. 253 (2008)) and used to study the development of glioma in (Frieboes et al., NeuroImage 37 (2007) and tumor invasion in (Bearer et al., Cancer Research, 69 (2009)) and (Frieboes et al., J. Theor. Biol. 264 (2010)). The model has a thermodynamic basis, is related to recently developed mixture models, and is capable of providing a detailed description of tumor progression. It utilizes a diffuse interface approach, whereby sharp tumor boundaries are replaced by narrow transition layers that arise due to differential adhesive forces among the cell-species. The model consists of fourth-order nonlinear advection-reaction-diffusion equations (of Cahn-Hilliard-type) for the cell-species coupled with reaction-diffusion equations for the substrate components. Numerical solution of the model is challenging because the equations are coupled, highly nonlinear, and numerically stiff. In this paper we describe a fully adaptive, nonlinear multigrid/finite difference method for efficiently solving the equations. We demonstrate the convergence of the algorithm and we present simulations of tumor growth in 2D and 3D that demonstrate the capabilities of the algorithm in accurately and efficiently simulating the progression of tumors with complex morphologies. PMID:21076663

  8. An Adaptive Simulation Framework for the Exploration of Extreme and Unexpected Events in Dynamic Engineered Systems.

    PubMed

    Turati, Pietro; Pedroni, Nicola; Zio, Enrico

    2017-01-01

    The end states reached by an engineered system during an accident scenario depend not only on the sequences of the events composing the scenario, but also on their timing and magnitudes. Including these additional features within an overarching framework can render the analysis infeasible in practical cases, due to the high dimension of the system state-space and the computational effort correspondingly needed to explore the possible system evolutions in search of the interesting (and very rare) ones of failure. To tackle this hurdle, in this article we introduce a framework for efficiently probing the space of event sequences of a dynamic system by means of a guided Monte Carlo simulation. Such framework is semi-automatic and allows embedding the analyst's prior knowledge about the system and his/her objectives of analysis. Specifically, the framework allows adaptively and intelligently allocating the simulation efforts preferably on those sequences leading to outcomes of interest for the objectives of the analysis, e.g., typically those that are more safety-critical (and/or rare). The emerging diversification in the filling of the state-space by the preference-guided exploration allows also the retrieval of critical system features, which can be useful to analysts and designers for taking appropriate means of prevention and mitigation of dangerous and/or unexpected consequences. A dynamic system for gas transmission is considered as a case study to demonstrate the application of the method.

  9. Adaptations to isolated shoulder fatigue during simulated repetitive work. Part II: Recovery.

    PubMed

    McDonald, Alison C; Tse, Calvin T F; Keir, Peter J

    2016-08-01

    The shoulder allows kinematic and muscular changes to facilitate continued task performance during prolonged repetitive work. The purpose of this work was to examine changes during simulated repetitive work in response to a fatigue protocol. Participants performed 20 one-minute work cycles comprised of 4 shoulder centric tasks, a fatigue protocol, followed by 60 additional cycles. The fatigue protocol targeted the anterior deltoid and cycled between static and dynamic actions. EMG was collected from 14 upper extremity and back muscles and three-dimensional motion was captured during each work cycle. Participants completed post-fatigue work despite EMG manifestations of muscle fatigue, reduced flexion strength (by 28%), and increased perceived exertion (∼3 times). Throughout the post-fatigue work cycles, participants maintained performance via kinematic and muscular adaptations, such as reduced glenohumeral flexion and scapular rotation which were task specific and varied throughout the hour of simulated work. By the end of 60 post-fatigue work cycles, signs of fatigue persisted in the anterior deltoid and developed in the middle deltoid, yet perceived exertion and strength returned to pre-fatigue levels. Recovery from fatigue elicits changes in muscle activity and movement patterns that may not be perceived by the worker which has important implications for injury risk.

  10. Dynamic adaptive chemistry with operator splitting schemes for reactive flow simulations

    NASA Astrophysics Data System (ADS)

    Ren, Zhuyin; Xu, Chao; Lu, Tianfeng; Singer, Michael A.

    2014-04-01

    A numerical technique that uses dynamic adaptive chemistry (DAC) with operator splitting schemes to solve the equations governing reactive flows is developed and demonstrated. Strang-based splitting schemes are used to separate the governing equations into transport fractional substeps and chemical reaction fractional substeps. The DAC method expedites the numerical integration of reaction fractional substeps by using locally valid skeletal mechanisms that are obtained using the directed relation graph (DRG) reduction method to eliminate unimportant species and reactions from the full mechanism. Second-order temporal accuracy of the Strang-based splitting schemes with DAC is demonstrated on one-dimensional, unsteady, freely-propagating, premixed methane/air laminar flames with detailed chemical kinetics and realistic transport. The use of DAC dramatically reduces the CPU time required to perform the simulation, and there is minimal impact on solution accuracy. It is shown that with DAC the starting species and resulting skeletal mechanisms strongly depend on the local composition in the flames. In addition, the number of retained species may be significant only near the flame front region where chemical reactions are significant. For the one-dimensional methane/air flame considered, speed-up factors of three and five are achieved over the entire simulation for GRI-Mech 3.0 and USC-Mech II, respectively. Greater speed-up factors are expected for larger chemical kinetics mechanisms.

  11. THREE-DIMENSIONAL ADAPTIVE MESH REFINEMENT SIMULATIONS OF LONG-DURATION GAMMA-RAY BURST JETS INSIDE MASSIVE PROGENITOR STARS

    SciTech Connect

    Lopez-Camara, D.; Lazzati, Davide; Morsony, Brian J.; Begelman, Mitchell C.

    2013-04-10

    We present the results of special relativistic, adaptive mesh refinement, 3D simulations of gamma-ray burst jets expanding inside a realistic stellar progenitor. Our simulations confirm that relativistic jets can propagate and break out of the progenitor star while remaining relativistic. This result is independent of the resolution, even though the amount of turbulence and variability observed in the simulations is greater at higher resolutions. We find that the propagation of the jet head inside the progenitor star is slightly faster in 3D simulations compared to 2D ones at the same resolution. This behavior seems to be due to the fact that the jet head in 3D simulations can wobble around the jet axis, finding the spot of least resistance to proceed. Most of the average jet properties, such as density, pressure, and Lorentz factor, are only marginally affected by the dimensionality of the simulations and therefore results from 2D simulations can be considered reliable.

  12. Impact of an Advanced Cardiac Life Support Simulation Laboratory Experience on Pharmacy Student Confidence and Knowledge

    PubMed Central

    Mohorn, Phillip L.; Haney, Jason S.; Phillips, Cynthia M.; Lu, Z. Kevin; Clark, Kimberly; Corboy, Alex; Ragucci, Kelly R.

    2016-01-01

    Objective. To assess the impact of an advanced cardiac life support (ACLS) simulation on pharmacy student confidence and knowledge. Design. Third-year pharmacy students participated in a simulation experience that consisted of team roles training, high-fidelity ACLS simulations, and debriefing. Students completed a pre/postsimulation confidence and knowledge assessment. Assessment. Overall, student knowledge assessment scores and student confidence scores improved significantly. Student confidence and knowledge changes from baseline were not significantly correlated. Conversely, a significant, weak positive correlation between presimulation studying and both presimulation confidence and presimulation knowledge was discovered. Conclusions. Overall, student confidence and knowledge assessment scores in ACLS significantly improved from baseline; however, student confidence and knowledge were not significantly correlated. PMID:27899836

  13. Impact of an Advanced Cardiac Life Support Simulation Laboratory Experience on Pharmacy Student Confidence and Knowledge.

    PubMed

    Maxwell, Whitney D; Mohorn, Phillip L; Haney, Jason S; Phillips, Cynthia M; Lu, Z Kevin; Clark, Kimberly; Corboy, Alex; Ragucci, Kelly R

    2016-10-25

    Objective. To assess the impact of an advanced cardiac life support (ACLS) simulation on pharmacy student confidence and knowledge. Design. Third-year pharmacy students participated in a simulation experience that consisted of team roles training, high-fidelity ACLS simulations, and debriefing. Students completed a pre/postsimulation confidence and knowledge assessment. Assessment. Overall, student knowledge assessment scores and student confidence scores improved significantly. Student confidence and knowledge changes from baseline were not significantly correlated. Conversely, a significant, weak positive correlation between presimulation studying and both presimulation confidence and presimulation knowledge was discovered. Conclusions. Overall, student confidence and knowledge assessment scores in ACLS significantly improved from baseline; however, student confidence and knowledge were not significantly correlated.

  14. Retention of Advanced Cardiac Life Support Knowledge and Skills Following High-Fidelity Mannequin Simulation Training

    PubMed Central

    Sen, Sanchita; Finn, Laura A.; Cawley, Michael J.

    2015-01-01

    Objective. To assess pharmacy students’ ability to retain advanced cardiac life support (ACLS) knowledge and skills within 120 days of previous high-fidelity mannequin simulation training. Design. Students were randomly assigned to rapid response teams of 5-6. Skills in ACLS and mannequin survival were compared between teams some members of which had simulation training 120 days earlier and teams who had not had previous training. Assessment. A checklist was used to record and assess performance in the simulations. Teams with previous simulation training (n=10) demonstrated numerical superiority to teams without previous training (n=12) for 6 out of 8 (75%) ACLS skills observed, including time calculating accurate vasopressor infusion rate (83 sec vs 113 sec; p=0.01). Mannequin survival was 37% higher for teams who had previous simulation training, but this result was not significant (70% vs 33%; p=0.20). Conclusion. Teams with students who had previous simulation training demonstrated numerical superiority in ACLS knowledge and skill retention within 120 days of previous training compared to those who had no previous training. Future studies are needed to add to the current evidence of pharmacy students’ and practicing pharmacists’ ACLS knowledge and skill retention. PMID:25741028

  15. Some psychophysiological and behavioral aspects of adaptation to simulated autonomous Mission to Mars

    NASA Astrophysics Data System (ADS)

    Gushin, V.; Shved, D.; Vinokhodova, A.; Vasylieva, G.; Nitchiporuk, I.; Ehmann, B.; Balazs, L.

    2012-01-01

    “Mars-105” experiment was executed in March-July 2009 in Moscow, at the Institute for Bio-Medical Problems (IBMP) with participation of European Space Agency (ESA) to simulate some specific conditions of future piloted Mars mission. In the last 35 days of isolation, in order to simulate autonomous flight conditions, some serious restrictions were established for the crew resupply and communication with Mission Control (MC). The objective of the study was to investigate psychophysiological and behavioral aspects (communication) of adaptation during this period of “high autonomy”. We used computerized analysis of the crew written daily reports to calculate the frequencies of utilization of certain semantic units, expressing different psychological functions. To estimate the level of psycho-physiological stress, we measured the concentration of urinal cortisol once in two weeks. To investigate psycho-emotional state, we used the questionnaire SAN, estimating Mood, Activity and Health once in two weeks.During the simulation of autonomous flight, we found out the different tendencies of communicative behavior. One group of subjects demonstrated the tendency to “activation and self-government” under “high autonomy” conditions. The other subjects continued to use communicative strategy that we called “closing the communication channel”. “Active” communication strategy was accompanied by increasing in subjective scores of mood and activity. The subjects, whose communication strategy was attributed as “closing”, demonstrated the considerably lower subjective scores of mood and activity. Period of high autonomy causes specific changes in communication strategies of the isolated crew.

  16. Using Multivariate Adaptive Regression Spline and Artificial Neural Network to Simulate Urbanization in Mumbai, India

    NASA Astrophysics Data System (ADS)

    Ahmadlou, M.; Delavar, M. R.; Tayyebi, A.; Shafizadeh-Moghadam, H.

    2015-12-01

    Land use change (LUC) models used for modelling urban growth are different in structure and performance. Local models divide the data into separate subsets and fit distinct models on each of the subsets. Non-parametric models are data driven and usually do not have a fixed model structure or model structure is unknown before the modelling process. On the other hand, global models perform modelling using all the available data. In addition, parametric models have a fixed structure before the modelling process and they are model driven. Since few studies have compared local non-parametric models with global parametric models, this study compares a local non-parametric model called multivariate adaptive regression spline (MARS), and a global parametric model called artificial neural network (ANN) to simulate urbanization in Mumbai, India. Both models determine the relationship between a dependent variable and multiple independent variables. We used receiver operating characteristic (ROC) to compare the power of the both models for simulating urbanization. Landsat images of 1991 (TM) and 2010 (ETM+) were used for modelling the urbanization process. The drivers considered for urbanization in this area were distance to urban areas, urban density, distance to roads, distance to water, distance to forest, distance to railway, distance to central business district, number of agricultural cells in a 7 by 7 neighbourhoods, and slope in 1991. The results showed that the area under the ROC curve for MARS and ANN was 94.77% and 95.36%, respectively. Thus, ANN performed slightly better than MARS to simulate urban areas in Mumbai, India.

  17. GAMMA-RAY BURST DYNAMICS AND AFTERGLOW RADIATION FROM ADAPTIVE MESH REFINEMENT, SPECIAL RELATIVISTIC HYDRODYNAMIC SIMULATIONS

    SciTech Connect

    De Colle, Fabio; Ramirez-Ruiz, Enrico; Granot, Jonathan; Lopez-Camara, Diego

    2012-02-20

    We report on the development of Mezcal-SRHD, a new adaptive mesh refinement, special relativistic hydrodynamics (SRHD) code, developed with the aim of studying the highly relativistic flows in gamma-ray burst sources. The SRHD equations are solved using finite-volume conservative solvers, with second-order interpolation in space and time. The correct implementation of the algorithms is verified by one-dimensional (1D) and multi-dimensional tests. The code is then applied to study the propagation of 1D spherical impulsive blast waves expanding in a stratified medium with {rho}{proportional_to}r{sup -k}, bridging between the relativistic and Newtonian phases (which are described by the Blandford-McKee and Sedov-Taylor self-similar solutions, respectively), as well as to a two-dimensional (2D) cylindrically symmetric impulsive jet propagating in a constant density medium. It is shown that the deceleration to nonrelativistic speeds in one dimension occurs on scales significantly larger than the Sedov length. This transition is further delayed with respect to the Sedov length as the degree of stratification of the ambient medium is increased. This result, together with the scaling of position, Lorentz factor, and the shock velocity as a function of time and shock radius, is explained here using a simple analytical model based on energy conservation. The method used for calculating the afterglow radiation by post-processing the results of the simulations is described in detail. The light curves computed using the results of 1D numerical simulations during the relativistic stage correctly reproduce those calculated assuming the self-similar Blandford-McKee solution for the evolution of the flow. The jet dynamics from our 2D simulations and the resulting afterglow light curves, including the jet break, are in good agreement with those presented in previous works. Finally, we show how the details of the dynamics critically depend on properly resolving the structure of the

  18. Gamma-Ray Burst Dynamics and Afterglow Radiation from Adaptive Mesh Refinement, Special Relativistic Hydrodynamic Simulations

    NASA Astrophysics Data System (ADS)

    De Colle, Fabio; Granot, Jonathan; López-Cámara, Diego; Ramirez-Ruiz, Enrico

    2012-02-01

    We report on the development of Mezcal-SRHD, a new adaptive mesh refinement, special relativistic hydrodynamics (SRHD) code, developed with the aim of studying the highly relativistic flows in gamma-ray burst sources. The SRHD equations are solved using finite-volume conservative solvers, with second-order interpolation in space and time. The correct implementation of the algorithms is verified by one-dimensional (1D) and multi-dimensional tests. The code is then applied to study the propagation of 1D spherical impulsive blast waves expanding in a stratified medium with ρvpropr -k , bridging between the relativistic and Newtonian phases (which are described by the Blandford-McKee and Sedov-Taylor self-similar solutions, respectively), as well as to a two-dimensional (2D) cylindrically symmetric impulsive jet propagating in a constant density medium. It is shown that the deceleration to nonrelativistic speeds in one dimension occurs on scales significantly larger than the Sedov length. This transition is further delayed with respect to the Sedov length as the degree of stratification of the ambient medium is increased. This result, together with the scaling of position, Lorentz factor, and the shock velocity as a function of time and shock radius, is explained here using a simple analytical model based on energy conservation. The method used for calculating the afterglow radiation by post-processing the results of the simulations is described in detail. The light curves computed using the results of 1D numerical simulations during the relativistic stage correctly reproduce those calculated assuming the self-similar Blandford-McKee solution for the evolution of the flow. The jet dynamics from our 2D simulations and the resulting afterglow light curves, including the jet break, are in good agreement with those presented in previous works. Finally, we show how the details of the dynamics critically depend on properly resolving the structure of the relativistic flow.

  19. Adaptation of Salmonella spp. in juice stored under refrigerated and room temperature enhances acid resistance to simulated gastric fluid.

    PubMed

    Yuk, H G; Schneider, K R

    2006-10-01

    The objective of this study was to evaluate the acid resistance of Salmonella spp. adapted in juices stored under refrigeration and room temperatures to simulated gastric fluid (SGF, pH 1.5). Five Salmonella serovars, Agona, Gaminara, Michigan, Montevideo, and Poona were used in this study. Apple, orange, and tomato juices inoculated with five serovars were stored at refrigeration (7 degrees C) and room temperature (20 degrees C) for 24 h for adaptation. Acid resistances of serovars adapted in juice were determined in SGF at 37 degrees C. All acid-adapted Salmonella serovars in juices displayed enhanced survival time compared to non-adapted controls. Among serovars, S. Poona adapted in apple at 20 degrees C and orange juices at 7 and 20 degrees C showed >2.0 log cfu/ml survivors, while the other serovars decreased to non-detectable level or <2.0 log cfu/ml for 100 s in SGF. Unlike apple and orange juices, all serovars adapted in tomato juice survived with >2.0 log cfu/ml for 100 s. For D-values, all Salmonella serovars adapted in apple and tomato juice enhanced their acid resistances compared to orange juices. S. Agona adapted in tomato juice at 7 degrees C and S. Poona in apple juice at 20 degrees C had the highest D-values with 82.9 and 82.5s, respectively. Results showed that the adaptation in juice increased acid resistance in SGF and varied by serovar, juice type, and adaptation temperature. Therefore, this study indicates that the introduction of Salmonella spp. to an acidic juice environment during processing can enhance their ability to survive in a human stomach, possibly increasing the risk of a Salmonella outbreak by juice.

  20. Mechanisms Underlying Adaptation to Life in Hydrogen Sulfide–Rich Environments

    PubMed Central

    Kelley, Joanna L.; Arias-Rodriguez, Lenin; Patacsil Martin, Dorrelyn; Yee, Muh-Ching; Bustamante, Carlos D.; Tobler, Michael

    2016-01-01

    Hydrogen sulfide (H2S) is a potent toxicant interfering with oxidative phosphorylation in mitochondria and creating extreme environmental conditions in aquatic ecosystems. The mechanistic basis of adaptation to perpetual exposure to H2S remains poorly understood. We investigated evolutionarily independent lineages of livebearing fishes that have colonized and adapted to springs rich in H2S and compared their genome-wide gene expression patterns with closely related lineages from adjacent, nonsulfidic streams. Significant differences in gene expression were uncovered between all sulfidic and nonsulfidic population pairs. Variation in the number of differentially expressed genes among population pairs corresponded to differences in divergence times and rates of gene flow, which is consistent with neutral drift driving a substantial portion of gene expression variation among populations. Accordingly, there was little evidence for convergent evolution shaping large-scale gene expression patterns among independent sulfide spring populations. Nonetheless, we identified a small number of genes that was consistently differentially expressed in the same direction in all sulfidic and nonsulfidic population pairs. Functional annotation of shared differentially expressed genes indicated upregulation of genes associated with enzymatic H2S detoxification and transport of oxidized sulfur species, oxidative phosphorylation, energy metabolism, and pathways involved in responses to oxidative stress. Overall, our results suggest that modification of processes associated with H2S detoxification and toxicity likely complement each other to mediate elevated H2S tolerance in sulfide spring fishes. Our analyses allow for the development of novel hypotheses about biochemical and physiological mechanisms of adaptation to extreme environments. PMID:26861137

  1. Scanning electron microscopy of Antarctophthirus microchir (Phthiraptera: Anoplura: Echinophthiriidae): studying morphological adaptations to aquatic life.

    PubMed

    Leonardi, María Soledad; Crespo, Enrique A; Raga, Juan Antonio; Fernández, Mercedes

    2012-09-01

    The members of the Family Echinophthiriidae (Phthiraptera: Anoplura) are unique among insects because they infest hosts with an amphibious lifestyle. During their evolution they developed morphological traits that are reflected in unique features. The SEM is a helpful tool to analyze them. Knowing in detail the external structure of these lice is the first step to understand the whole process that derived from the co-adaptation of lice and pinnipeds to the marine environment. For the first time, we studied the external structure of all stages of an echinophthiriid louse. The results are discussed in the light of their evolutionary, functional, and ecological implications.

  2. Translation, Adaptation and Initial Validation of Food Allergy Quality of Life Questionnaire: Child form in Greek

    PubMed Central

    Morou, Zoe; Lyrakos, Georgios N.; Papadopoulos, Nikolaos G.; Douladiris, Nikolaos; Tatsioni, Athina; Dimoliatis, Ioannis D.K.

    2016-01-01

    The aim of the study is to determine the reliability and validity of the Greek version of the Food Allergy Quality of life Questionnaire-Child Form (FAQLQ-CF). After linguistic validation, the Greek FAQLQ-CF, Food Allergy Independent Measure (FAIM) and Pediatric Quality of Life Inventory (PedsQL™) were used by a physician to interview children diagnosed with food allergy and aged 8-12 via telephone. Cronbach’s alpha was used to evaluate reliability, and factor analysis to assess construct validity. The correlation between FAQLQ-CF and FAIM was moderate (rho=0.509, P<0.001) and internal consistency was strong (Cronbach’s alpha 0.905). FAQLQ-CF discriminated well each question’s contribution to children’s quality of life deterioration (32-80%), each child’s quality of life (17-89%), children differing in doing things with others (total score 3.55 vs 2.57, difference =0.98 > minimal clinical importance difference = 0.5; P<0.001), but not children differing in reporting anaphylaxis. The total FAQLQ-CF score correlated with the total PedsQL™ score and with the score of one of PedsQL™ subscales, demonstrating convergent validity. Factor analysis uncovered an underlying structure of four factors, explaining 50% of the variance. We can conclude that Greek FAQLQ-CF is a reliable, valid, discriminant tool for interviewing food allergic children aged 8-12, detecting those in need for immediate care. PMID:27403459

  3. Adaptation and evaluation of the Liverpool Seizure Severity Scale and Liverpool Quality of Life battery for American epilepsy patients.

    PubMed

    Rapp, S; Shumaker, S; Smith, T; Gibson, P; Berzon, R; Hoffman, R

    1998-05-01

    The Liverpool Seizure Severity Scale (LSSS) and the Liverpool Quality of Life (LQOL) battery were developed in Great Britain to assess the severity of seizure symptoms and the impact of epilepsy on patients' quality of life. The scales have been validated on British patients, but have not been validated for use with American patients. The objectives of this study were to adapt the scales to the American population and to evaluate their reliability and validity. After modifications recommended by focus groups with patients and epilepsy specialists, the scales were administered to a sample of 90 epilepsy patients who had experienced seizures within the previous 4 weeks. Comparisons of patients with generalized tonic-clonic seizures (n = 58) and partial seizures (n = 32) revealed significant differences on 12 of the 20 items on the LSSS as well as the total score. None of the six LQOL subscales (negative drug effects, positive drug effects, affect balance, sense of mastery, life fulfillment and impact of epilepsy) distinguished patients with different seizure types but five of the six subscales were significantly correlated with seizure severity. The internal consistency and test-retest reliability were adequate for both the LSSS and LQOL. Finally, five of the six LQOL scales were significantly correlated with independent measures of mental health, physical health and role functioning.

  4. Adaptation and evaluation of the Liverpool Seizure Severity Scale and Liverpool Quality of Life battery for American epilepsy patients.

    PubMed

    Rapp, S; Shumaker, S; Smith, T; Gibson, P; Berzon, R; Hoffman, R

    1998-08-01

    The Liverpool Seizure Severity Scale (LSSS) and the Liverpool Quality of Life (LQOL) battery were developed in Great Britain to assess the severity of seizure symptoms and the impact of epilepsy on patients' quality of life. The scales have been validated on British patients, but have not been validated for use with American patients. The objectives of this study were to adapt the scales to the American population and to evaluate their reliability and validity. After modifications recommended by focus groups with patients and epilepsy specialists, the scales were administered to a sample of 90 epilepsy patients who had experienced seizures within the previous 4 weeks. Comparisons of patients with generalized tonic-clonic seizures (n = 58) and partial seizures (n = 32) revealed significant differences on 9 of the 20 items on the LSSS as well as the total score. None of the six LQOL subscales (negative drug effects, positive drug effects, affect balance, sense of mastery, life fulfilment and impact of epilepsy) distinguished patients with different seizure types but five of the six subscales were significantly correlated with seizure severity. The internal consistency and test-retest reliability were adequate for both the LSSS and LQOL. Finally, five of the six LQOL scales were significantly correlated with independent measures of mental health, physical health and role functioning.

  5. Geographic body size variation in the periodical cicadas Magicicada: implications for life cycle divergence and local adaptation.

    PubMed

    Koyama, T; Ito, H; Kakishima, S; Yoshimura, J; Cooley, J R; Simon, C; Sota, T

    2015-06-01

    Seven species in three species groups (Decim, Cassini and Decula) of periodical cicadas (Magicicada) occupy a wide latitudinal range in the eastern United States. To clarify how adult body size, a key trait affecting fitness, varies geographically with climate conditions and life cycle, we analysed the relationships of population mean head width to geographic variables (latitude, longitude, altitude), habitat annual mean temperature (AMT), life cycle and species differences. Within species, body size was larger in females than males and decreased with increasing latitude (and decreasing habitat AMT), following the converse Bergmann's rule. For the pair of recently diverged 13- and 17-year species in each group, 13-year cicadas were equal in size or slightly smaller on average than their 17-year counterparts despite their shorter developmental time. This fact suggests that, under the same climatic conditions, 17-year cicadas have lowered growth rates compared to their 13-years counterparts, allowing 13-year cicadas with faster growth rates to achieve body sizes equivalent to those of their 17-year counterparts at the same locations. However, in the Decim group, which includes two 13-year species, the more southerly, anciently diverged 13-year species (Magicicada tredecim) was characterized by a larger body size than the other, more northerly 13- and 17-year species, suggesting that local adaptation in warmer habitats may ultimately lead to evolution of larger body sizes. Our results demonstrate how geographic clines in body size may be maintained in sister species possessing different life cycles.

  6. Acquisition and adaptation of the airway microbiota in the early life of cystic fibrosis patients.

    PubMed

    Boutin, Sébastien; Dalpke, Alexander H

    2017-12-01

    Cystic fibrosis (CF) is a genetic disease in which bacterial infections of the airways play a major role in the long-term clinical outcome. In recent years, a number of next-generation sequencing (NGS)-based studies aimed at deciphering the structure and composition of the airways' microbiota. It was shown that the nasal cavity of CF patients displays dysbiosis early in life indicating a failure in the first establishment of a healthy microbiota. In contrast, within the conducting and lower airways, the establishment occurs normally first, but is sensitive to future dysbiosis including chronic infections with classical pathogens in later life. The objective of this mini-review is to give an update on the current knowledge about the development of the microbiota in the early life of CF patients. Microbial acquisition in the human airways can be described by the island model: Microbes found in the lower airways of CF patients represent "islands" that are at first populated from the upper airways reflecting the "mainland." Colonization can be modeled following the neutral theory in which the most abundant bacteria in the mainland are also frequently found in the lower airways initially. At later times, however, the colonization process of the lower airways segregates by active selection of specific microbes. Future research should focus on those processes of microbial and host interactions to understand how microbial communities are shaped on short- and long-term scales. We point out what therapeutic consequences arise from the microbiome data obtained within ecological framework models.

  7. Grid generation and adaptation for the Direct Simulation Monte Carlo Method. [for complex flows past wedges and cones

    NASA Technical Reports Server (NTRS)

    Olynick, David P.; Hassan, H. A.; Moss, James N.

    1988-01-01

    A grid generation and adaptation procedure based on the method of transfinite interpolation is incorporated into the Direct Simulation Monte Carlo Method of Bird. In addition, time is advanced based on a local criterion. The resulting procedure is used to calculate steady flows past wedges and cones. Five chemical species are considered. In general, the modifications result in a reduced computational effort. Moreover, preliminary results suggest that the simulation method is time step dependent if requirements on cell sizes are not met.

  8. King of the mountains: Tibetan and Sherpa physiological adaptations for life at high altitude.

    PubMed

    Gilbert-Kawai, Edward T; Milledge, James S; Grocott, Michael P W; Martin, Daniel S

    2014-11-01

    Anecdotal evidence surrounding Tibetans' and Sherpas' exceptional tolerance to hypobaric hypoxia has been recorded since the beginning of high-altitude exploration. These populations have successfully lived and reproduced at high altitude for hundreds of generations with hypoxia as a constant evolutionary pressure. Consequently, they are likely to have undergone natural selection toward a genotype (and phenotype) tending to offer beneficial adaptation to sustained hypoxia. With the advent of translational human hypoxic research, in which genotype/phenotype studies of healthy individuals at high altitude may be of benefit to hypoxemic critically ill patients in a hospital setting, high-altitude natives may provide a valuable and intriguing model. The aim of this review is to provide a comprehensive summary of the scientific literature encompassing Tibetan and Sherpa physiological adaptations to a high-altitude residence. The review demonstrates the extent to which evolutionary pressure has refined the physiology of this high-altitude population. Furthermore, although many physiological differences between highlanders and lowlanders have been found, it also suggests many more potential avenues of investigation.

  9. How does life adapt to a gravitational environment? The outline of the terrestrial gastropod shell.

    PubMed

    Okajima, Ryoko; Chiba, Satoshi

    2011-12-01

    How do several characteristics adapt to gravity while mutually influencing each other? Our study addresses this issue by focusing on the terrestrial gastropod shell. The geometric relationship between the spire index (shell height/diameter) and outline (cylindricality) is theoretically estimated. When the shell grows isometrically, a high-spired shell becomes conical in shape and a low-spired shell becomes cylindrical in shape. A physical model shows that the lowest- and highest-spired shells are the most balanced. In addition, a cone shape is the most balanced for a low-spired shell, and a column shape is the most balanced for a high-spired shell. Spire index and cylindricality measured for freshwater gastropods follow the relationship estimated by the model, whereas those for terrestrial gastropods deviate from this relationship. This translates to a high shell being more cylindrical than a flat shell, except in the case of extremely high or low shells. This suggests that the shape of the most balanced shells (lowest and highest shell heights) is constrained by coiling geometry but that relatively unbalanced shells (intermediate shell heights) do not follow a coiling geometry, as a result of adaptation to enable the snail to carry its shell more effectively.

  10. Compressible magma/mantle dynamics: 3-D, adaptive simulations in ASPECT

    NASA Astrophysics Data System (ADS)

    Dannberg, Juliane; Heister, Timo

    2016-12-01

    Melt generation and migration are an important link between surface processes and the thermal and chemical evolution of the Earth's interior. However, their vastly different timescales make it difficult to study mantle convection and melt migration in a unified framework, especially for 3-D global models. And although experiments suggest an increase in melt volume of up to 20 per cent from the depth of melt generation to the surface, previous computations have neglected the individual compressibilities of the solid and the fluid phase. Here, we describe our extension of the finite element mantle convection code ASPECT that adds melt generation and migration. We use the original compressible formulation of the McKenzie equations, augmented by an equation for the conservation of energy. Applying adaptive mesh refinement to this type of problems is particularly advantageous, as the resolution can be increased in areas where melt is present and viscosity gradients are high, whereas a lower resolution is sufficient in regions without melt. Together with a high-performance, massively parallel implementation, this allows for high-resolution, 3-D, compressible, global mantle convection simulations coupled with melt migration. We evaluate the functionality and potential of this method using a series of benchmarks and model setups, compare results of the compressible and incompressible formulation, and show the effectiveness of adaptive mesh refinement when applied to melt migration. Our model of magma dynamics provides a framework for modelling processes on different scales and investigating links between processes occurring in the deep mantle and melt generation and migration. This approach could prove particularly useful applied to modelling the generation of komatiites or other melts originating in greater depths. The implementation is available in the Open Source ASPECT repository.

  11. Simulated adaptations to an adult dietary self-report tool to accommodate children: Impact on nutrient estimates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our objective was to simulate the effect of child-friendly (CF) adaptations of the National Cancer Institute’s Automated Self-Administered 24-Hour Dietary Recall (ASA24) on estimates of nutrient intake. One hundred twenty children, 8–13 years old, entered their previous day’s intake using the ASA24 ...

  12. The performance of field scientists undertaking observations of early life fossils while in simulated space suit

    NASA Astrophysics Data System (ADS)

    Willson, D.; Rask, J. C.; George, S. C.; de Leon, P.; Bonaccorsi, R.; Blank, J.; Slocombe, J.; Silburn, K.; Steele, H.; Gargarno, M.; McKay, C. P.

    2014-01-01

    We conducted simulated Apollo Extravehicular Activity's (EVA) at the 3.45 Ga Australian 'Pilbara Dawn of life' (Western Australia) trail with field and non-field scientists using the University of North Dakota's NDX-1 pressurizable space suit to overview the effectiveness of scientist astronauts employing their field observation skills while looking for stromatolite fossil evidence. Off-world scientist astronauts will be faced with space suit limitations in vision, human sense perception, mobility, dexterity, the space suit fit, time limitations, and the psychological fear of death from accidents, causing physical fatigue reducing field science performance. Finding evidence of visible biosignatures for past life such as stromatolite fossils, on Mars, is a very significant discovery. Our preliminary overview trials showed that when in simulated EVAs, 25% stromatolite fossil evidence is missed with more incorrect identifications compared to ground truth surveys but providing quality characterization descriptions becomes less affected by simulated EVA limitations as the science importance of the features increases. Field scientists focused more on capturing high value characterization detail from the rock features whereas non-field scientists focused more on finding many features. We identified technologies and training to improve off-world field science performance. The data collected is also useful for NASA's "EVA performance and crew health" research program requirements but further work will be required to confirm the conclusions.

  13. Systematic testing of flood adaptation options in urban areas through simulations

    NASA Astrophysics Data System (ADS)

    Löwe, Roland; Urich, Christian; Sto. Domingo, Nina; Mark, Ole; Deletic, Ana; Arnbjerg-Nielsen, Karsten

    2016-04-01

    While models can quantify flood risk in great detail, the results are subject to a number of deep uncertainties. Climate dependent drivers such as sea level and rainfall intensities, population growth and economic development all have a strong influence on future flood risk, but future developments can only be estimated coarsely. In such a situation, robust decision making frameworks call for the systematic evaluation of mitigation measures against ensembles of potential futures. We have coupled the urban development software DAnCE4Water and the 1D-2D hydraulic simulation package MIKE FLOOD to create a framework that allows for such systematic evaluations, considering mitigation measures under a variety of climate futures and urban development scenarios. A wide spectrum of mitigation measures can be considered in this setup, ranging from structural measures such as modifications of the sewer network over local retention of rainwater and the modification of surface flow paths to policy measures such as restrictions on urban development in flood prone areas or master plans that encourage compact development. The setup was tested in a 300 ha residential catchment in Melbourne, Australia. The results clearly demonstrate the importance of considering a range of potential futures in the planning process. For example, local rainwater retention measures strongly reduce flood risk a scenario with moderate increase of rain intensities and moderate urban growth, but their performance strongly varies, yielding very little improvement in situations with pronounced climate change. The systematic testing of adaptation measures further allows for the identification of so-called adaptation tipping points, i.e. levels for the drivers of flood risk where the desired level of flood risk is exceeded despite the implementation of (a combination of) mitigation measures. Assuming a range of development rates for the drivers of flood risk, such tipping points can be translated into

  14. Activities and Adaptation in Late-Life Depression: A Qualitative Study

    PubMed Central

    Holm, Margo B.; Raina, Ketki D.; Reynolds, Charles F.; Rogers, Joan C.

    2014-01-01

    OBJECTIVE. We sought to understand activity choices of older adults when they were depressed. METHOD. Each community-dwelling participant (n = 27) completed one semistructured interview while in recovery for at least 3 mo. but less than 7 mo. Transcripts were coded to identify relevant themes. RESULTS. Six themes emerged that explained activities participants continued while depressed, and four themes described activities they stopped. CONCLUSION. Older adults maintained many instrumental activities of daily living while depressed, and some actively adapted activities so they could continue them. Some intentionally stopped activities to direct limited energy to their highest priority activities. To guide effective intervention, it is critical for occupational therapy practitioners to complete a client-centered qualitative assessment to understand what and, most important, why activities are continued or stopped. Each theme for activities continued and activities stopped lends itself to intervention strategies. PMID:25184470

  15. Collembolan Transcriptomes Highlight Molecular Evolution of Hexapods and Provide Clues on the Adaptation to Terrestrial Life

    PubMed Central

    Faddeeva, A.; Studer, R. A.; Kraaijeveld, K.; Sie, D.; Ylstra, B.; Mariën, J.; op den Camp, H. J. M.; Datema, E.; den Dunnen, J. T.; van Straalen, N. M.; Roelofs, D.

    2015-01-01

    Background Collembola (springtails) represent a soil-living lineage of hexapods in between insects and crustaceans. Consequently, their genomes may hold key information on the early processes leading to evolution of Hexapoda from a crustacean ancestor. Method We assembled and annotated transcriptomes of the Collembola Folsomia candida and Orchesella cincta, and performed comparative analysis with protein-coding gene sequences of three crustaceans and three insects to identify adaptive signatures associated with the evolution of hexapods within the pancrustacean clade. Results Assembly of the springtail transcriptomes resulted in 37,730 transcripts with predicted open reading frames for F. candida and 32,154 for O. cincta, of which 34.2% were functionally annotated for F. candida and 38.4% for O. cincta. Subsequently, we predicted orthologous clusters among eight species and applied the branch-site test to detect episodic positive selection in the Hexapoda and Collembola lineages. A subset of 250 genes showed significant positive selection along the Hexapoda branch and 57 in the Collembola lineage. Gene Ontology categories enriched in these genes include metabolism, stress response (i.e. DNA repair, immune response), ion transport, ATP metabolism, regulation and development-related processes (i.e. eye development, neurological development). Conclusions We suggest that the identified gene families represent processes that have played a key role in the divergence of hexapods within the pancrustacean clade that eventually evolved into the most species-rich group of all animals, the hexapods. Furthermore, some adaptive signatures in collembolans may provide valuable clues to understand evolution of hexapods on land. PMID:26075903

  16. Assessing the performance of life-cycle portfolio allocation strategies for retirement saving: a simulation study.

    PubMed

    Bridges, Benjamin; Gesumaria, Robert; Leonesio, Michael V

    2010-01-01

    This article examines the performance of four life-cycle portfolio allocation strategies through stochastic simulation based on observed U.S. asset returns during 1926-2008. Annual worker contributions to retirement savings accounts are based on the actual lifetime earnings histories maintained by the Social Security Administration for 12,871 workers born during 1915-1942. Each strategy's performance is evaluated primarily on the basis of the distributions of internal rates of return on investments calculated at the time of retirement. Comparisons are made with the performance of four other investment strategies that vary in terms of their exposure to stock and bond market risk. Life-cycle plans with larger portfolio weights assigned to equities have higher average returns, but those gains come at the cost of increased risk of infrequent bad outcomes.

  17. Numerical Simulations of Optical Turbulence Using an Advanced Atmospheric Prediction Model: Implications for Adaptive Optics Design

    NASA Astrophysics Data System (ADS)

    Alliss, R.

    2014-09-01

    Optical turbulence (OT) acts to distort light in the atmosphere, degrading imagery from astronomical telescopes and reducing the data quality of optical imaging and communication links. Some of the degradation due to turbulence can be corrected by adaptive optics. However, the severity of optical turbulence, and thus the amount of correction required, is largely dependent upon the turbulence at the location of interest. Therefore, it is vital to understand the climatology of optical turbulence at such locations. In many cases, it is impractical and expensive to setup instrumentation to characterize the climatology of OT, so numerical simulations become a less expensive and convenient alternative. The strength of OT is characterized by the refractive index structure function Cn2, which in turn is used to calculate atmospheric seeing parameters. While attempts have been made to characterize Cn2 using empirical models, Cn2 can be calculated more directly from Numerical Weather Prediction (NWP) simulations using pressure, temperature, thermal stability, vertical wind shear, turbulent Prandtl number, and turbulence kinetic energy (TKE). In this work we use the Weather Research and Forecast (WRF) NWP model to generate Cn2 climatologies in the planetary boundary layer and free atmosphere, allowing for both point-to-point and ground-to-space seeing estimates of the Fried Coherence length (ro) and other seeing parameters. Simulations are performed using a multi-node linux cluster using the Intel chip architecture. The WRF model is configured to run at 1km horizontal resolution and centered on the Mauna Loa Observatory (MLO) of the Big Island. The vertical resolution varies from 25 meters in the boundary layer to 500 meters in the stratosphere. The model top is 20 km. The Mellor-Yamada-Janjic (MYJ) TKE scheme has been modified to diagnose the turbulent Prandtl number as a function of the Richardson number, following observations by Kondo and others. This modification

  18. Putting μ/g in a new light: plasticity in life history switch points reflects fine-scale adaptive responses.

    PubMed

    Touchon, Justin C; McCoy, Michael W; Landberg, Tobias; Vonesh, James R; Warkentin, Karen M

    2015-08-01

    of the "minimize µ/g" framework. Our results demonstrate that likely adaptive changes in life history transitions occur at previously unappreciated timescales. Consideration of plasticity in the developmental timing of ecologically important events within metamorphosis, rather than treating it as a discrete switch point, may help to reconcile inconsistencies between empirical studies of predator effects and expectations of long-standing ecological theory.

  19. The spectrin-ankyrin-4.1-adducin membrane skeleton: adapting eukaryotic cells to the demands of animal life.

    PubMed

    Baines, Anthony J

    2010-08-01

    The cells in animals face unique demands beyond those encountered by their unicellular eukaryotic ancestors. For example, the forces engendered by the movement of animals places stresses on membranes of a different nature than those confronting free-living cells. The integration of cells into tissues, as well as the integration of tissue function into whole animal physiology, requires specialisation of membrane domains and the formation of signalling complexes. With the evolution of mammals, the specialisation of cell types has been taken to an extreme with the advent of the non-nucleated mammalian red blood cell. These and other adaptations to animal life seem to require four proteins--spectrin, ankyrin, 4.1 and adducin--which emerged during eumetazoan evolution. Spectrin, an actin cross-linking protein, was probably the earliest of these, with ankyrin, adducin and 4.1 only appearing as tissues evolved. The interaction of spectrin with ankyrin is probably a prerequisite for the formation of tissues; only with the advent of vertebrates did 4.1 acquires the ability to bind spectrin and actin. The latter activity seems to allow the spectrin complex to regulate the cell surface accumulation of a wide variety of proteins. Functionally, the spectrin-ankyrin-4.1-adducin complex is implicated in the formation of apical and basolateral domains, in aspects of membrane trafficking, in assembly of certain signalling and cell adhesion complexes and in providing stability to otherwise mechanically fragile cell membranes. Defects in this complex are manifest in a variety of hereditary diseases, including deafness, cardiac arrhythmia, spinocerebellar ataxia, as well as hereditary haemolytic anaemias. Some of these proteins also function as tumor suppressors. The spectrin-ankyrin-4.1-adducin complex represents a remarkable system that underpins animal life; it has been adapted to many different functions at different times during animal evolution.

  20. Flight Test of an Adaptive Controller and Simulated Failure/Damage on the NASA NF-15B

    NASA Technical Reports Server (NTRS)

    Buschbacher, Mark; Maliska, Heather

    2006-01-01

    The method of flight-testing the Intelligent Flight Control System (IFCS) Second Generation (Gen-2) project on the NASA NF-15B is herein described. The Gen-2 project objective includes flight-testing a dynamic inversion controller augmented by a direct adaptive neural network to demonstrate performance improvements in the presence of simulated failure/damage. The Gen-2 objectives as implemented on the NASA NF-15B created challenges for software design, structural loading limitations, and flight test operations. Simulated failure/damage is introduced by modifying control surface commands, therefore requiring structural loads measurements. Flight-testing began with the validation of a structural loads model. Flight-testing of the Gen-2 controller continued, using test maneuvers designed in a sequenced approach. Success would clear the new controller with respect to dynamic response, simulated failure/damage, and with adaptation on and off. A handling qualities evaluation was conducted on the capability of the Gen-2 controller to restore aircraft response in the presence of a simulated failure/damage. Control room monitoring of loads sensors, flight dynamics, and controller adaptation, in addition to postflight data comparison to the simulation, ensured a safe methodology of buildup testing. Flight-testing continued without major incident to accomplish the project objectives, successfully uncovering strengths and weaknesses of the Gen-2 control approach in flight.

  1. Reproductive seasonality in captive wild ruminants: implications for biogeographical adaptation, photoperiodic control, and life history.

    PubMed

    Zerbe, Philipp; Clauss, Marcus; Codron, Daryl; Bingaman Lackey, Laurie; Rensch, Eberhard; Streich, Jürgen W; Hatt, Jean-Michel; Müller, Dennis W H

    2012-11-01

    Many ruminant species show seasonal patterns of reproduction. Causes for this are widely debated, and include adaptations to seasonal availability of resources (with cues either from body condition in more tropical, or from photoperiodism in higher latitude habitats) and/or defence strategies against predators. Conclusions so far are limited to datasets with less than 30 species. Here, we use a dataset on 110 wild ruminant species kept in captivity in temperate-zone zoos to describe their reproductive patterns quantitatively [determining the birth peak breadth (BPB) as the number of days in which 80% of all births occur]; then we link this pattern to various biological characteristics [latitude of origin, mother-young-relationship (hider/follower), proportion of grass in the natural diet (grazer/browser), sexual size dimorphism/mating system], and compare it with reports for free-ranging animals. When comparing taxonomic subgroups, variance in BPB is highly correlated to the minimum, but not the maximum BPB, suggesting that a high BPB (i.e. an aseasonal reproductive pattern) is the plesiomorphic character in ruminants. Globally, latitude of natural origin is highly correlated to the BPB observed in captivity, supporting an overruling impact of photoperiodism on ruminant reproduction. Feeding type has no additional influence; the hider/follower dichotomy, associated with the anti-predator strategy of 'swamping', has additional influence in the subset of African species only. Sexual size dimorphism and mating system are marginally associated with the BPB, potentially indicating a facilitation of polygamy under seasonal conditions. The difference in the calculated Julian date of conception between captive populations and that reported for free-ranging ones corresponds to the one expected if absolute day length was the main trigger in highly seasonal species: calculated day length at the time of conception between free-ranging and captive populations followed a y = x

  2. A general hybrid radiation transport scheme for star formation simulations on an adaptive grid

    SciTech Connect

    Klassen, Mikhail; Pudritz, Ralph E.; Kuiper, Rolf; Peters, Thomas; Banerjee, Robi; Buntemeyer, Lars

    2014-12-10

    Radiation feedback plays a crucial role in the process of star formation. In order to simulate the thermodynamic evolution of disks, filaments, and the molecular gas surrounding clusters of young stars, we require an efficient and accurate method for solving the radiation transfer problem. We describe the implementation of a hybrid radiation transport scheme in the adaptive grid-based FLASH general magnetohydrodyanmics code. The hybrid scheme splits the radiative transport problem into a raytracing step and a diffusion step. The raytracer captures the first absorption event, as stars irradiate their environments, while the evolution of the diffuse component of the radiation field is handled by a flux-limited diffusion solver. We demonstrate the accuracy of our method through a variety of benchmark tests including the irradiation of a static disk, subcritical and supercritical radiative shocks, and thermal energy equilibration. We also demonstrate the capability of our method for casting shadows and calculating gas and dust temperatures in the presence of multiple stellar sources. Our method enables radiation-hydrodynamic studies of young stellar objects, protostellar disks, and clustered star formation in magnetized, filamentary environments.

  3. A General Hybrid Radiation Transport Scheme for Star Formation Simulations on an Adaptive Grid

    NASA Astrophysics Data System (ADS)

    Klassen, Mikhail; Kuiper, Rolf; Pudritz, Ralph E.; Peters, Thomas; Banerjee, Robi; Buntemeyer, Lars

    2014-12-01

    Radiation feedback plays a crucial role in the process of star formation. In order to simulate the thermodynamic evolution of disks, filaments, and the molecular gas surrounding clusters of young stars, we require an efficient and accurate method for solving the radiation transfer problem. We describe the implementation of a hybrid radiation transport scheme in the adaptive grid-based FLASH general magnetohydrodyanmics code. The hybrid scheme splits the radiative transport problem into a raytracing step and a diffusion step. The raytracer captures the first absorption event, as stars irradiate their environments, while the evolution of the diffuse component of the radiation field is handled by a flux-limited diffusion solver. We demonstrate the accuracy of our method through a variety of benchmark tests including the irradiation of a static disk, subcritical and supercritical radiative shocks, and thermal energy equilibration. We also demonstrate the capability of our method for casting shadows and calculating gas and dust temperatures in the presence of multiple stellar sources. Our method enables radiation-hydrodynamic studies of young stellar objects, protostellar disks, and clustered star formation in magnetized, filamentary environments.

  4. Robust and adaptive techniques for numerical simulation of nonlinear partial differential equations of fractional order

    NASA Astrophysics Data System (ADS)

    Owolabi, Kolade M.

    2017-03-01

    In this paper, some nonlinear space-fractional order reaction-diffusion equations (SFORDE) on a finite but large spatial domain x ∈ [0, L], x = x(x , y , z) and t ∈ [0, T] are considered. Also in this work, the standard reaction-diffusion system with boundary conditions is generalized by replacing the second-order spatial derivatives with Riemann-Liouville space-fractional derivatives of order α, for 0 < α < 2. Fourier spectral method is introduced as a better alternative to existing low order schemes for the integration of fractional in space reaction-diffusion problems in conjunction with an adaptive exponential time differencing method, and solve a range of one-, two- and three-components SFORDE numerically to obtain patterns in one- and two-dimensions with a straight forward extension to three spatial dimensions in a sub-diffusive (0 < α < 1) and super-diffusive (1 < α < 2) scenarios. It is observed that computer simulations of SFORDE give enough evidence that pattern formation in fractional medium at certain parameter value is practically the same as in the standard reaction-diffusion case. With application to models in biology and physics, different spatiotemporal dynamics are observed and displayed.

  5. Numerical simulation of an adaptive optics system with laser propagation in the atmosphere.

    PubMed

    Yan, H X; Li, S S; Zhang, D L; Chen, S

    2000-06-20

    A comprehensive model of laser propagation in the atmosphere with a complete adaptive optics (AO) system for phase compensation is presented, and a corresponding computer program is compiled. A direct wave-front gradient control method is used to reconstruct the wave-front phase. With the long-exposure Strehl ratio as the evaluation parameter, a numerical simulation of an AO system in a stationary state with the atmospheric propagation of a laser beam was conducted. It was found that for certain conditions the phase screen that describes turbulence in the atmosphere might not be isotropic. Numerical experiments show that the computational results in imaging of lenses by means of the fast Fourier transform (FFT) method agree well with those computed by means of an integration method. However, the computer time required for the FFT method is 1 order of magnitude less than that of the integration method. Phase tailoring of the calculated phase is presented as a means to solve the problem that variance of the calculated residual phase does not correspond to the correction effectiveness of an AO system. It is found for the first time to our knowledge that for a constant delay time of an AO system, when the lateral wind speed exceeds a threshold, the compensation effectiveness of an AO system is better than that of complete phase conjugation. This finding indicates that the better compensation capability of an AO system does not mean better correction effectiveness.

  6. Direct calculation of 1-octanol-water partition coefficients from adaptive biasing force molecular dynamics simulations.

    PubMed

    Bhatnagar, Navendu; Kamath, Ganesh; Chelst, Issac; Potoff, Jeffrey J

    2012-07-07

    The 1-octanol-water partition coefficient log K(ow) of a solute is a key parameter used in the prediction of a wide variety of complex phenomena such as drug availability and bioaccumulation potential of trace contaminants. In this work, adaptive biasing force molecular dynamics simulations are used to determine absolute free energies of hydration, solvation, and 1-octanol-water partition coefficients for n-alkanes from methane to octane. Two approaches are evaluated; the direct transfer of the solute from 1-octanol to water phase, and separate transfers of the solute from the water or 1-octanol phase to vacuum, with both methods yielding statistically indistinguishable results. Calculations performed with the TIP4P and SPC∕E water models and the TraPPE united-atom force field for n-alkanes show that the choice of water model has a negligible effect on predicted free energies of transfer and partition coefficients for n-alkanes. A comparison of calculations using wet and dry octanol phases shows that the predictions for log K(ow) using wet octanol are 0.2-0.4 log units lower than for dry octanol, although this is within the statistical uncertainty of the calculation.

  7. A memory structure adapted simulated annealing algorithm for a green vehicle routing problem.

    PubMed

    Küçükoğlu, İlker; Ene, Seval; Aksoy, Aslı; Öztürk, Nursel

    2015-03-01

    Currently, reduction of carbon dioxide (CO2) emissions and fuel consumption has become a critical environmental problem and has attracted the attention of both academia and the industrial sector. Government regulations and customer demands are making environmental responsibility an increasingly important factor in overall supply chain operations. Within these operations, transportation has the most hazardous effects on the environment, i.e., CO2 emissions, fuel consumption, noise and toxic effects on the ecosystem. This study aims to construct vehicle routes with time windows that minimize the total fuel consumption and CO2 emissions. The green vehicle routing problem with time windows (G-VRPTW) is formulated using a mixed integer linear programming model. A memory structure adapted simulated annealing (MSA-SA) meta-heuristic algorithm is constructed due to the high complexity of the proposed problem and long solution times for practical applications. The proposed models are integrated with a fuel consumption and CO2 emissions calculation algorithm that considers the vehicle technical specifications, vehicle load, and transportation distance in a green supply chain environment. The proposed models are validated using well-known instances with different numbers of customers. The computational results indicate that the MSA-SA heuristic is capable of obtaining good G-VRPTW solutions within a reasonable amount of time by providing reductions in fuel consumption and CO2 emissions.

  8. [Adaptability of mangrove Avicennia marina seedlings to simulated tide-inundated times].

    PubMed

    Liao, Bao-wen; Qiu, Feng-ying; Zhang, Liu-en; Han, Jing; Guan, Wei

    2010-05-01

    A laboratory test on the effects of differents simulated tide-inundated times with 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24 h x d(-1) on the growth of Avicennia marina seedlings was conducted. The ten growth information indices including chlorophyll, root vigor, growth, biomass and photosynthetic rate were mensurated. The principal components analysis was made combining the ten growth information indices. The 210 d experimental results showed that the chlorophyll, root vigor, growth and biomass would rise first and then fall as the extension of the inundate time; and they changed suddenly at the threshold inundate time 16 h x d(-1). The growth and biomass of Avicennia marina seedlings with more than 16 hours tide-inundated time per day were less than them with no more than 16 hours tide-inundated time per day. The maximum value of stem increment each month, leaf blade increment each month, dry weight of stem, dry weight of root and total biomass were under the 10 hours tide-inundated time per day. It concluded that Avicennia marina seedlings would grow adaptively with less than 16 hours tide-inundated time per day, 8-12 hours of tide-inundated time per day is the most suitable for the growth of Avicennia marina seedlings, while 16 h x d(-1) is a critical tide-inundated time when the plant responded to be obviously inadaptable.

  9. A moderate swimming exercise regularly performed throughout the life induces age and sex-related modifications in adaptive macronutrients choice.

    PubMed

    Boghossian, S; Alliot, J

    2000-12-01

    The ability of laboratory rats to adapt food intake to needs is well-known. The present study investigates changes in this adaptive behavior when animals grow old. A cohort of male and female Lou/c/jall rats was regularly submitted to an exercise throughout their life (6 consecutive days of moderate intensity training (3x15 min/day)). Caloric intake and macronutrients selection during exercise and post-exercise periods were compared to the pre-training period. During swimming, a decrease in both caloric intake and fat selection was observed and an increase in protein intake was specifically seen in female groups. However, males were unable to modify the diet composition (macronutrient rate) from 16 months of age, whereas females were able to do it until 24 months of age. The present results suggest a sex-dependent loss of capacity of adjusting feeding behavior to metabolic needs when animals grow old, may be due to a deterioration of the central control of food intake.

  10. Entamoeba histolytica adaptation to glucose starvation: a matter of life and death.

    PubMed

    Baumel-Alterzon, Sharon; Ankri, Serge

    2014-08-01

    Parasites are often challenged by constant changes of the glucose concentration in their different hosts and/or within the different biotopes in the same host. During its life cycle, Entamoeba histolytica, the causative protozoan parasite of human amoebiasis, is exposed to both a glucose-poor environment in the colon and a glucose-rich environment in the liver. High-throughput 'omics' technologies are now widely used to characterize the cell's global response to various stresses and these technologies can survey E. histolytica's global response to fluctuations in glucose concentration in its environment. In this review, we discuss the phenotypic and metabolic responses of E. histolytica to glucose challenges, and compare these responses to those of other protozoan parasites.

  11. Online fault adaptive control for efficient resource management in Advanced Life Support Systems

    NASA Technical Reports Server (NTRS)

    Abdelwahed, Sherif; Wu, Jian; Biswas, Gautam; Ramirez, John; Manders, Eric-J

    2005-01-01

    This article presents the design and implementation of a controller scheme for efficient resource management in Advanced Life Support Systems. In the proposed approach, a switching hybrid system model is used to represent the dynamics of the system components and their interactions. The operational specifications for the controller are represented by utility functions, and the corresponding resource management problem is formulated as a safety control problem. The controller is designed as a limited-horizon online supervisory controller that performs a limited forward search on the state-space of the system at each time step, and uses the utility functions to decide on the best action. The feasibility and accuracy of the online algorithm can be assessed at design time. We demonstrate the effectiveness of the scheme by running a set of experiments on the Reverse Osmosis (RO) subsystem of the Water Recovery System (WRS).

  12. Moroccan adaptation and validation of the rhinosinusitis quality-of-life survey.

    PubMed

    Adouly, Taoufik; Adnane, Choaib; Khallouk, Amine; Chenguir, Meriem; Rouadi, Sami; Abada, Reda Lah; Roubal, Mohamed; Mahtar, Mohamed

    2017-03-01

    The aim of this study was to validate the Moroccan translation and sociocultural adaptation of the RhinoQOL questionnaire. The questionnaires were translated into Moroccan and then translated back into English. The final version was administered twice to an asymptomatic control population (n = 50) and once to a patients with chronic rhinosinusitis (CRS) undergoing functional endoscopic sinus surgery (FESS) (n = 99). Both of the groups answered the questionnaire before and one year after surgery. The psychometric properties, reliability, validity with correlation to other clinical instruments and responsiveness to treatment, were analyzed. Univariate and multivariate analyses were performed. The test-retest reliability was excellent [intraclass correlation coefficient (ICC) >0.9], indicating a good reliability when administering the instrument on repeated occasions. The internal consistency was 0.80, 0.75 and 0.94 for the scores of the RhinoQOL sub-scales (frequency, bothersomeness, and impact, respectively). Firstly, our questionnaire was able to detect differences between patients with CRS and group of healthy volunteers (p < 0.0001) and secondly, it improved significantly after surgery (p < 0.0001), indicating a good responsiveness. A good correlation was found between the Moroccan version, the preoperative objective scores, and SNOT-22 and RSDI scores. The Moroccan RhinoQOL questionnaire appears to be culturally appropriate and psychometrically valid.

  13. Family Wide Molecular Adaptations to Underground Life in African Mole-Rats Revealed by Phylogenomic Analysis.

    PubMed

    Davies, Kalina T J; Bennett, Nigel C; Tsagkogeorga, Georgia; Rossiter, Stephen J; Faulkes, Christopher G

    2015-12-01

    During their evolutionary radiation, mammals have colonized diverse habitats. Arguably the subterranean niche is the most inhospitable of these, characterized by reduced oxygen, elevated carbon dioxide, absence of light, scarcity of food, and a substrate that is energetically costly to burrow through. Of all lineages to have transitioned to a subterranean niche, African mole-rats are one of the most successful. Much of their ecological success can be attributed to a diet of plant storage organs, which has allowed them to colonize climatically varied habitats across sub-Saharan Africa, and has probably contributed to the evolution of their diverse social systems. Yet despite their many remarkable phenotypic specializations, little is known about molecular adaptations underlying these traits. To address this, we sequenced the transcriptomes of seven mole-rat taxa, including three solitary species, and combined new sequences with existing genomic data sets. Alignments of more than 13,000 protein-coding genes encompassed, for the first time, all six genera and the full spectrum of ecological and social variation in the clade. We detected positive selection within the mole-rat clade and along ancestral branches in approximately 700 genes including loci associated with tumorigenesis, aging, morphological development, and sociality. By combining these results with gene ontology annotation and protein-protein networks, we identified several clusters of functionally related genes. This family wide analysis of molecular evolution in mole-rats has identified a suite of positively selected genes, deepening our understanding of the extreme phenotypic traits exhibited by this group.

  14. Life at the border: Adaptation of proteins to anisotropic membrane environment

    PubMed Central

    Pogozheva, Irina D; Mosberg, Henry I; Lomize, Andrei L

    2014-01-01

    This review discusses main features of transmembrane (TM) proteins which distinguish them from water-soluble proteins and allow their adaptation to the anisotropic membrane environment. We overview the structural limitations on membrane protein architecture, spatial arrangement of proteins in membranes and their intrinsic hydrophobic thickness, co-translational and post-translational folding and insertion into lipid bilayers, topogenesis, high propensity to form oligomers, and large-scale conformational transitions during membrane insertion and transport function. Special attention is paid to the polarity of TM protein surfaces described by profiles of dipolarity/polarizability and hydrogen-bonding capacity parameters that match polarity of the lipid environment. Analysis of distributions of Trp resides on surfaces of TM proteins from different biological membranes indicates that interfacial membrane regions with preferential accumulation of Trp indole rings correspond to the outer part of the lipid acyl chain region—between double bonds and carbonyl groups of lipids. These “midpolar” regions are not always symmetric in proteins from natural membranes. We also examined the hydrophobic effect that drives insertion of proteins into lipid bilayer and different free energy contributions to TM protein stability, including attractive van der Waals forces and hydrogen bonds, side-chain conformational entropy, the hydrophobic mismatch, membrane deformations, and specific protein–lipid binding. PMID:24947665

  15. Simple mechanisms of early life - simulation model on the origin of semi-cells.

    PubMed

    Klein, Adrian; Bock, Martin; Alt, Wolfgang

    2017-01-01

    The development of first cellular structures played an important role in the early evolution of life. Early evolution of life probably took place on a molecular level in a reactive environment. The iron-sulfur theory postulates the formation of cell-like structures on catalytic surfaces. Experiments show that H2S together with FeS and other metallic centers drive auto-catalytic surface reactions, in which organic molecules such as pyruvic and amino acids occur. It is questionable which mechanisms are needed to form cell-like structures under these conditions. To address this question, we implemented a model system featuring the fundamentals of molecular dynamics: heat, attraction, repulsion and formation of covalent bonds. Our basic model exhibits a series of essential processes: self-organization of lipid micelles and bilayers, formation of fluid filled cavities, flux of molecules along membranes, transport of energized groups towards sinks and whole colonies of cell-like structures on a larger scale. The results demonstrate that only a few features are sufficient for discovering hitherto non described phenomena of self-assembly and dynamics of cell-like structures as candidates for early evolving proto-cells. Significance statement The quest for a possible origin of life continues to be one of the most fascinating problems in biology. In one theoretical scenario, early life originated from a solution of reactive chemicals in the ancient deep sea, similar to conditions as to be found in thermal vents. Experiments have shown that a variety of organic molecules, the building blocks of life, form under these conditions. Based on such experiments, the iron-sulfur theory postulates the growth of cell-like structures at certain catalytic surfaces. For an explanation and proof of such a process we have developed a computer model simulating molecular assembly of lipid bilayers and formation of semi-cell cavities. The results demonstrate the possibility of cell-like self

  16. Applying Computerized Adaptive Testing to the Four-Dimensional Symptom Questionnaire (4DSQ): A Simulation Study

    PubMed Central

    de Beurs, Derek P; Terluin, Berend; Verhaak, Peter F

    2017-01-01

    Background Efficient screening questionnaires are useful in general practice. Computerized adaptive testing (CAT) is a method to improve the efficiency of questionnaires, as only the items that are particularly informative for a certain responder are dynamically selected. Objective The objective of this study was to test whether CAT could improve the efficiency of the Four-Dimensional Symptom Questionnaire (4DSQ), a frequently used self-report questionnaire designed to assess common psychosocial problems in general practice. Methods A simulation study was conducted using a sample of Dutch patients visiting a general practitioner (GP) with psychological problems (n=379). Responders completed a paper-and-pencil version of the 50-item 4DSQ and a psychometric evaluation was performed to check if the data agreed with item response theory (IRT) assumptions. Next, a CAT simulation was performed for each of the four 4DSQ scales (distress, depression, anxiety, and somatization), based on the given responses as if they had been collected through CAT. The following two stopping rules were applied for the administration of items: (1) stop if measurement precision is below a predefined level, or (2) stop if more than half of the items of the subscale are administered. Results In general, the items of each of the four scales agreed with IRT assumptions. Application of the first stopping rule reduced the length of the questionnaire by 38% (from 50 to 31 items on average). When the second stopping rule was also applied, the total number of items could be reduced by 56% (from 50 to 22 items on average). Conclusions CAT seems useful for improving the efficiency of the 4DSQ by 56% without losing a considerable amount of measurement precision. The CAT version of the 4DSQ may be useful as part of an online assessment to investigate the severity of mental health problems of patients visiting a GP. This simulation study is the first step needed for the development a CAT version of the 4

  17. Advancing adaptive optics technology: Laboratory turbulence simulation and optimization of laser guide stars

    NASA Astrophysics Data System (ADS)

    Rampy, Rachel A.

    Since Galileo's first telescope some 400 years ago, astronomers have been building ever-larger instruments. Yet only within the last two decades has it become possible to realize the potential angular resolutions of large ground-based telescopes, by using adaptive optics (AO) technology to counter the blurring effects of Earth's atmosphere. And only within the past decade have the development of laser guide stars (LGS) extended AO capabilities to observe science targets nearly anywhere in the sky. Improving turbulence simulation strategies and LGS are the two main topics of my research. In the first part of this thesis, I report on the development of a technique for manufacturing phase plates for simulating atmospheric turbulence in the laboratory. The process involves strategic application of clear acrylic paint onto a transparent substrate. Results of interferometric characterization of the plates are described and compared to Kolmogorov statistics. The range of r0 (Fried's parameter) achieved thus far is 0.2--1.2 mm at 650 nm measurement wavelength, with a Kolmogorov power law. These plates proved valuable at the Laboratory for Adaptive Optics at University of California, Santa Cruz, where they have been used in the Multi-Conjugate Adaptive Optics testbed, during integration and testing of the Gemini Planet Imager, and as part of the calibration system of the on-sky AO testbed named ViLLaGEs (Visible Light Laser Guidestar Experiments). I present a comparison of measurements taken by ViLLaGEs of the power spectrum of a plate and the real sky turbulence. The plate is demonstrated to follow Kolmogorov theory well, while the sky power spectrum does so in a third of the data. This method of fabricating phase plates has been established as an effective and low-cost means of creating simulated turbulence. Due to the demand for such devices, they are now being distributed to other members of the AO community. The second topic of this thesis pertains to understanding and

  18. Validation through simulations of a C_n^2 profiler for the ESO/VLT Adaptive Optics Facility

    NASA Astrophysics Data System (ADS)

    Garcia-Rissmann, A.; Guesalaga, A.; Kolb, J.; Le Louarn, M.; Madec, P.-Y.; Neichel, B.

    2015-04-01

    The Adaptive Optics Facility (AOF) project envisages transforming one of the VLT units into an adaptive telescope and providing its ESO (European Southern Observatory) second generation instruments with turbulence-corrected wavefronts. For MUSE and HAWK-I this correction will be achieved through the GALACSI and GRAAL AO modules working in conjunction with a 1170 actuators deformable secondary mirror (DSM) and the new Laser Guide Star Facility (4LGSF). Multiple wavefront sensors will enable GLAO (ground layer adaptive optics) and LTAO (laser tomography adaptive optics) capabilities, whose performance can greatly benefit from a knowledge about the stratification of the turbulence in the atmosphere. This work, totally based on end-to-end simulations, describes the validation tests conducted on a C_n^2 profiler adapted for the AOF specifications. Because an absolute profile calibration is strongly dependent on a reliable knowledge of turbulence parameters r0 and L0, the tests presented here refer only to normalized output profiles. Uncertainties in the input parameters inherent to the code are tested as well as the profiler response to different turbulence distributions. It adopts a correction for the unseen turbulence, critical for the GRAAL mode, and highlights the effects of masking out parts of the corrected wavefront on the results. Simulations of data with typical turbulence profiles from Paranal were input to the profiler, showing that it is possible to identify reliably the input features for all the AOF modes.

  19. Using the virtual reality world of second life to teach nursing faculty simulation management.

    PubMed

    Weiner, Elizabeth; McNew, Ryan; Trangenstein, Patricia; Gordon, Jeffry

    2010-01-01

    Healthcare faculty members have come to depend on the advantages of teaching with clinical simulation, but not all faculty are competent in their ability to manage students during the simulation experience. This federally funded proposal provided the opportunity for nursing faculty to participate in a synchronous learning event using the virtual reality world of Second Life (SL). Based on competencies, faculty participants were guided through the simulation process by a "Master Teacher." Participants then became the teacher and chose the settings, objectives, and clinical data to manage their own simulation using avatar role assignments. Feedback populated the participant informatics dashboard, so that progress towards their competencies was recorded. Another unique informatics application was the use of the Synthetic Derivative project to use de-identified patient data to promote better clinical realism. Additional evaluation activities regarding content, appropriate use of the technology, and design features were assessed. The development of the SL environment for this educational study provides the setting in which to pilot test the provision of actual clinical care that does not require "hands-on" interventions.

  20. Family Wide Molecular Adaptations to Underground Life in African Mole-Rats Revealed by Phylogenomic Analysis

    PubMed Central

    Davies, Kalina T.J.; Bennett, Nigel C.; Tsagkogeorga, Georgia; Rossiter, Stephen J.; Faulkes, Christopher G.

    2015-01-01

    During their evolutionary radiation, mammals have colonized diverse habitats. Arguably the subterranean niche is the most inhospitable of these, characterized by reduced oxygen, elevated carbon dioxide, absence of light, scarcity of food, and a substrate that is energetically costly to burrow through. Of all lineages to have transitioned to a subterranean niche, African mole-rats are one of the most successful. Much of their ecological success can be attributed to a diet of plant storage organs, which has allowed them to colonize climatically varied habitats across sub-Saharan Africa, and has probably contributed to the evolution of their diverse social systems. Yet despite their many remarkable phenotypic specializations, little is known about molecular adaptations underlying these traits. To address this, we sequenced the transcriptomes of seven mole-rat taxa, including three solitary species, and combined new sequences with existing genomic data sets. Alignments of more than 13,000 protein-coding genes encompassed, for the first time, all six genera and the full spectrum of ecological and social variation in the clade. We detected positive selection within the mole-rat clade and along ancestral branches in approximately 700 genes including loci associated with tumorigenesis, aging, morphological development, and sociality. By combining these results with gene ontology annotation and protein–protein networks, we identified several clusters of functionally related genes. This family wide analysis of molecular evolution in mole-rats has identified a suite of positively selected genes, deepening our understanding of the extreme phenotypic traits exhibited by this group. PMID:26318402

  1. Sensitivity and adaptability of methanogens to perchlorates: Implications for life on Mars

    NASA Astrophysics Data System (ADS)

    Kral, Timothy A.; Goodhart, Timothy H.; Harpool, Joshua D.; Hearnsberger, Christopher E.; McCracken, Graham L.; McSpadden, Stanley W.

    2016-01-01

    % indicating some success in adapting cells to concentrations higher than 1%. The results reported here indicate that the presence of perchlorate on Mars does not rule out the possible existence of methanogens.

  2. How many genes to start with? A computer simulation about the origin of life

    NASA Astrophysics Data System (ADS)

    Niesert, Ursula

    1987-06-01

    A geneticist's view on the origin of life would focus on individual nucleic acid molecules rather than on their concentrations, on stochastics rather than on differential equations. The ‘package model’ envisages primordial compartments that contain ensembles of primordial genes. These are replicated independently from each other. During package fission they are distributed to two daughter packages. Packages with a complete ensemble of genes can continue to propagate. However, mutations as well as the stochastic nature of replication and package fission occasionally cause arising packages to miss genes from the ensemble, thus resulting in the death of those packages. A computer simulation, considering the complementarity of RNA as well as abortive termination of replication, yielded results that are similar to those of a preliminary simulation irrespective of these parameters: the results suggest that life could not have started with more than 3 genes, or else the primordial replicase would have to achieve at least a reduction of the replicational error rate by a factor of 13 and a reduction of undue chain termination by a factor of 10 to 25.

  3. Progress towards computer simulation of NiH2 battery performance over life

    NASA Technical Reports Server (NTRS)

    Zimmerman, Albert H.; Quinzio, M. V.

    1995-01-01

    The long-term performance of rechargeable battery cells has traditionally been verified through life-testing, a procedure that generally requires significant commitments of funding and test resources. In the situation of nickel hydrogen battery cells, which have the capability of providing extremely long cycle life, the time and cost required to conduct even accelerated testing has become a serious impediment to transitioning technology improvements into spacecraft applications. The utilization of computer simulations to indicate the changes in performance to be expected in response to design or operating changes in nickel hydrogen cells is therefore a particularly attractive tool in advanced battery development, as well as for verifying performance in different applications. Computer-based simulations of the long-term performance of rechargeable battery cells have typically had very limited success in the past. There are a number of reasons for the lack in progress in this area. First, and probably most important, all battery cells are relatively complex electrochemical systems, in which performance is dictated by a large number of interacting physical and chemical processes. While the complexity alone is a significant part of the problem, in many instances the fundamental chemical and physical processes underlying long-term degradation and its effects on performance have not even been understood. Second, while specific chemical and physical changes within cell components have been associated with degradation, there has been no generalized simulation architecture that enables the chemical and physical structure (and changes therein) to be translated into cell performance. For the nickel hydrogen battery cell, our knowledge of the underlying reactions that control the performance of this cell has progressed to where it clearly is possible to model them. The recent development of a relative generalized cell modelling approach provides the framework for translating

  4. Modeling and simulation of an aquatic habitat for bioregenerative life support research

    NASA Astrophysics Data System (ADS)

    Drayer, Gregorio E.; Howard, Ayanna M.

    2014-01-01

    Long duration human spaceflight poses challenges for spacecraft autonomy and the regeneration of life support consumables, such as oxygen and water. Bioregenerative life support systems (BLSS), which make use of biological processes to transform biological byproducts back into consumables, have the ability to recycle organic byproducts and are the preferred option for food production. A limitation in BLSS research is in the non-availability of small-scale experimental capacities that may help to better understand the challenges in system closure, integration, and control. Ground-based aquatic habitats are an option for small-scale research relevant to bioregenerative life support systems (BLSS), given that they can operate as self-contained systems enclosing a habitat composed of various species in a single volume of water. The purpose of this paper is to present the modeling and simulation of a reconfigurable aquatic habitat for experiments in regenerative life support automation; it supports the use of aquatic habitats as a small-scale approach to experiments relevant to larger-scale regenerative life support systems. It presents ground-based aquatic habitats as an option for small-scale BLSS research focusing on the process of respiration, and elaborates on the description of biological processes by introducing models of ecophysiological phenomena for consumers and producers: higher plants of the species Bacopa monnieri produce O2 for snails of the genus Pomacea; the snails consume O2 and generate CO2, which is used by the plants in combination with radiant energy to generate O2 through the process of photosynthesis. Feedback controllers are designed to regulate the concentration of dissolved oxygen in the water. This paper expands the description of biological processes by introducing models of ecophysiological phenomena of the organisms involved. The model of the plants includes a description of the rate of CO2 assimilation as a function of irradiance

  5. Adaptive strategies and life history characteristics in a warming climate: salmon in the Arctic?

    USGS Publications Warehouse

    Nielsen, Jennifer L.; Ruggerone, Gregory T.; Zimmerman, Christian E.

    2013-01-01

    In the warming Arctic, aquatic habitats are in flux and salmon are exploring their options. Adult Pacific salmon, including sockeye (Oncorhynchus nerka), coho (O. kisutch), Chinook (O. tshawytscha), pink (O. gorbuscha) and chum (O. keta) have been captured throughout the Arctic. Pink and chum salmon are the most common species found in the Arctic today. These species are less dependent on freshwater habitats as juveniles and grow quickly in marine habitats. Putative spawning populations are rare in the North American Arctic and limited to pink salmon in drainages north of Point Hope, Alaska, chum salmon spawning rivers draining to the northwestern Beaufort Sea, and small populations of chum and pink salmon in Canada’s Mackenzie River. Pacific salmon have colonized several large river basins draining to the Kara, Laptev and East Siberian seas in the Russian Arctic. These populations probably developed from hatchery supplementation efforts in the 1960’s. Hundreds of populations of Arctic Atlantic salmon (Salmo salar) are found in Russia, Norway and Finland. Atlantic salmon have extended their range eastward as far as the Kara Sea in central Russian. A small native population of Atlantic salmon is found in Canada’s Ungava Bay. The northern tip of Quebec seems to be an Atlantic salmon migration barrier for other North American stocks. Compatibility between life history requirements and ecological conditions are prerequisite for salmon colonizing Arctic habitats. Broad-scale predictive models of climate change in the Arctic give little information about feedback processes contributing to local conditions, especially in freshwater systems. This paper reviews the recent history of salmon in the Arctic and explores various patterns of climate change that may influence range expansions and future sustainability of salmon in Arctic habitats. A summary of the research needs that will allow informed expectation of further Arctic colonization by salmon is given.

  6. Biogenic hydrogen peroxide as a possible adaptation of life on Mars: the search for biosignatures

    NASA Astrophysics Data System (ADS)

    Houtkooper, J. M.; Schulze-Makuch, D.

    2007-08-01

    The hypothesis that putative Martian organisms incorporate H2O2 into their intracellular liquids (Houtkooper and Schulze-Makuch, 2007) has significant implications, as it explains the Viking observations quite well; it provides a functional adaptation to Martian environmental conditions; and, it is feasible as an adaptation based on the biochemistry of terrestrial organisms. It would explain many of the puzzling Viking observations such as (1) the lack of organics detected by GC-MS, (2) the lack of detected oxidant(s) to support a chemical explanation, (3) evolution of O2 upon wetting (GEx experiment), (4) limited organic synthesis reactions (PR experiment), and (5) the gas release observations made (LR experiment). An intracellular liquid containing a high concentration of H2O2 has advantages such as providing a low freezing point, a source of oxygen, and hygroscopicity, allowing an organism to obtain water vapor from the Martian atmosphere or from the adsorbed layers of water molecules on mineral grains. Perhaps surprisingly, H2O2 is used by many terrestrial organisms for diverse purposes, e.g., metabolism (Acetobacter peroxidans), as defense mechanism (Bombardier beetle), and also to mediate diverse physiological responses such as cell proliferation, differentiation, and migration. The detection of H2O2-containing organisms may well suffer from the same problems as the Viking experiments: Because of the excess oxidative contents, as derived from the GEx experiment, the organisms may decompose completely into H2O, CO2, O2 and N2. This can happen when exposed to an excess of water vapor (through hyperhydration), too high a temperature or a combination of both. Therefore, the addition of too much water vapor may be fatal. Moreover, employing pyrolysis in order to detect organic molecules may result in the organisms autooxidizing completely. Although the instrument suite aboard the Phoenix Lander offers some interesting possibilities (Schulze-Makuch and Houtkooper

  7. Subjective Well-Being and Adaptation to Life Events: A Meta-Analysis on Differences Between Cognitive and Affective Well-Being

    PubMed Central

    Luhmann, Maike; Hofmann, Wilhelm; Eid, Michael; Lucas, Richard E.

    2012-01-01

    Previous research has shown that major life events can have short- and long-term effects on subjective well-being (SWB). The present meta-analysis examines (a) whether life events have different effects on cognitive and affective well-being and (b) how the rate of adaptation varies across different life events. Longitudinal data from 188 publications (313 samples, N = 65,911) were integrated to describe the reaction and adaptation to four family events (marriage, divorce, bereavement, child birth) and four work events (unemployment, reemployment, retirement, relocation/migration). The findings show that life events have very different effects on affective and cognitive well-being, and that for most events the effects of life events on cognitive well-being are stronger and more consistent across samples. Different life events differ in their effects on SWB, but these effects are not a function of the alleged desirability of events. The results are discussed with respect to their theoretical implications, and recommendations for future studies on adaptation are given. PMID:22059843

  8. Simulated rugby performance at 1550-m altitude following adaptation to intermittent normobaric hypoxia.

    PubMed

    Hamlin, Michael J; Hinckson, Erica A; Wood, Matthew R; Hopkins, Will G

    2008-11-01

    Team-sport athletes who normally reside at sea level occasionally play games at altitudes sufficient to impair endurance performance. To investigate the effect of intermittent normobaric hypoxic exposure on performance in generic and game-specific tests at altitude, 22 senior club level rugby players performed baseline tests before single-blind random assignment to one of three groups: hypoxia-altitude (n=9), normoxia-altitude (n=6), and normoxia-sea level (n=7). The hypoxia-altitude group underwent 9-13 sessions of intermittent hypoxic exposure (concentration of inspired oxygen=13-10%) over 15 days, then repeated the performance tests within 12h of travelling to 1550m. The normoxia-altitude group underwent placebo exposures by breathing room air before repeating the tests at altitude, whereas the normoxia-sea level group underwent placebo exposures before repeating the tests at sea level. Hypoxic exposure consisted of alternately breathing 6min hypoxic gas and 4min ambient air for 1h at rest. Performance measures gathered at each testing session were maximum speed, sub-maximum heart-rate speed and sub-maximum lactate speed during a 20-m incremental running test, mean time in six 70-m sprints, repetitive explosive power and other measures from seven 5.5-min circuits of a rugby simulation. Repetitive explosive power ( approximately -16%) and 20-m shuttle performance ( approximately -3%) decreased substantially at altitude compared to sea level. Acclimatisation to hypoxia had a beneficial effect on sub-maximum heart rate and lactate speed but little effect on other performance measures. In conclusion, 1550-m altitude substantially impaired some measures of performance and the effects of prior adaptation via 9-13 sessions of intermittent hypoxia were mostly unclear.

  9. Classical to path-integral adaptive resolution in molecular simulation: towards a smooth quantum-classical coupling.

    PubMed

    Poma, A B; Delle Site, L

    2010-06-25

    Simulations that couple different molecular models in an adaptive way by changing resolution on the fly allow us to identify the relevant degrees of freedom of a system. This, in turn, leads to a detailed understanding of the essential physics which characterizes a system. While the delicate process of transition from one model to another is well understood for the adaptivity between classical molecular models the same cannot be said for the quantum-classical adaptivity. The main reason for this is the difficulty in describing a continuous transition between two different kinds of physical principles: probabilistic for the quantum and deterministic for the classical. Here we report the basic principles of an algorithm that allows for a continuous and smooth transition by employing the path integral description of atoms.

  10. Simulation and analysis of laser guide star adaptive optics systems for the eight to ten meter class telescopes

    SciTech Connect

    Gavel, D.T.; Olivier, S.S.

    1994-03-01

    This paper discusses the design and analysis of laser-guided adaptive optic systems for the large, 8--10 meter class telescopes. We describe a technique for calculating the expected modulation transfer function and the point spread function for a closed loop adaptive optics system, parameterized by the degree of correction and the seeing conditions. The results agree closely with simulations and experimental data, and validate well known scaling law models even at low order correction. Scaling law.model analysis of a proposed adaptive optics system at the Keck telescope leads to the conclusion that a single laser guide star beacon will be adequate for diffraction limited imaging at wavelengths between 1 and 3 am with reasonable coverage of the sky. Cone anisoplanatism will dominate wavefront correction error at the visible wavelengths unless multiple laser guide stars are used.

  11. Utility of Emulation and Simulation Computer Modeling of Space Station Environmental Control and Life Support Systems

    NASA Technical Reports Server (NTRS)

    Yanosy, James L.

    1988-01-01

    Over the years, computer modeling has been used extensively in many disciplines to solve engineering problems. A set of computer program tools is proposed to assist the engineer in the various phases of the Space Station program from technology selection through flight operations. The development and application of emulation and simulation transient performance modeling tools for life support systems are examined. The results of the development and the demonstration of the utility of three computer models are presented. The first model is a detailed computer model (emulation) of a solid amine water desorbed (SAWD) CO2 removal subsystem combined with much less detailed models (simulations) of a cabin, crew, and heat exchangers. This model was used in parallel with the hardware design and test of this CO2 removal subsystem. The second model is a simulation of an air revitalization system combined with a wastewater processing system to demonstrate the capabilities to study subsystem integration. The third model is that of a Space Station total air revitalization system. The station configuration consists of a habitat module, a lab module, two crews, and four connecting nodes.

  12. `Grandeur in this view of life': N-body simulation models of the Galactic habitable zone

    NASA Astrophysics Data System (ADS)

    Vukotić, B.; Steinhauser, D.; Martinez-Aviles, G.; Ćirković, M. M.; Micic, M.; Schindler, S.

    2016-07-01

    We present an isolated Milky-Way-like simulation in the GADGET2 N-body smoothed particle hydrodynamics (SPH) code. The Galactic disc star formation rate (SFR) surface densities and a stellar mass indicative of the Solar neighbourhood are used as thresholds to model the distribution of stellar mass in life-friendly environments. SFR and stellar component density are calculated by averaging the GADGET2 particle properties on a 2D grid mapped on the Galactic plane. The peak values for possibly habitable stellar mass surface density move from 10 to 15 kpc cylindrical galactocentric distance in a 10-Gyr simulated time span. At 10 Gyr, the simulation results imply the following. Stellar particles that have spent almost all of their lifetime in habitable-friendly conditions typically reside at ˜16 kpc from the Galactic Centre and are ˜3 Gyr old. Stellar particles that have spent ≥90 per cent of their 4-5 Gyr long lifetime in habitable-friendly conditions are also predominantly found in the outskirts of the Galactic disc. Fewer than 1 per cent of these particles can be found at a typical Solar system galactocentric distance of 8-10 kpc. Our results imply that the evolution of an isolated spiral galaxy is likely to result in galactic civilizations emerging at the outskirts of the galactic disc around stellar hosts younger than the Sun.

  13. A novel medical image data-based multi-physics simulation platform for computational life sciences.

    PubMed

    Neufeld, Esra; Szczerba, Dominik; Chavannes, Nicolas; Kuster, Niels

    2013-04-06

    Simulating and modelling complex biological systems in computational life sciences requires specialized software tools that can perform medical image data-based modelling, jointly visualize the data and computational results, and handle large, complex, realistic and often noisy anatomical models. The required novel solvers must provide the power to model the physics, biology and physiology of living tissue within the full complexity of the human anatomy (e.g. neuronal activity, perfusion and ultrasound propagation). A multi-physics simulation platform satisfying these requirements has been developed for applications including device development and optimization, safety assessment, basic research, and treatment planning. This simulation platform consists of detailed, parametrized anatomical models, a segmentation and meshing tool, a wide range of solvers and optimizers, a framework for the rapid development of specialized and parallelized finite element method solvers, a visualization toolkit-based visualization engine, a Python scripting interface for customized applications, a coupling framework, and more. Core components are cross-platform compatible and use open formats. Several examples of applications are presented: hyperthermia cancer treatment planning, tumour growth modelling, evaluating the magneto-haemodynamic effect as a biomarker and physics-based morphing of anatomical models.

  14. The Virtual Habitat - A tool for dynamic life support system simulations

    NASA Astrophysics Data System (ADS)

    Czupalla, M.; Zhukov, A.; Schnaitmann, J.; Olthoff, C.; Deiml, M.; Plötner, P.; Walter, U.

    2015-06-01

    In this paper we present the Virtual Habitat (V-HAB) model, which simulates on a system level the dynamics of entire mission scenarios for any given life support system (LSS) including a dynamic representation of the crew. We first present the V-HAB architecture. Thereafter we validate in selected case studies the V-HAB submodules. Finally, we demonstrate the overall abilities of V-HAB by first simulating the LSS of the International Space Station (ISS) and showing how close this comes to real data. In a second case study we simulate the LSS dynamics of a Mars mission scenario. We thus show that V-HAB is able to support LSS design processes, giving LSS designers a set of dynamic decision parameters (e.g. stability, robustness, effective crew time) at hand that supplement or even substitute the common Equivalent System Mass (ESM) quantities as a proxy for LSS hardware costs. The work presented here builds on a LSS heritage by the exploration group at the Technical University at Munich (TUM) dating from even before 2006.

  15. A novel medical image data-based multi-physics simulation platform for computational life sciences

    PubMed Central

    Neufeld, Esra; Szczerba, Dominik; Chavannes, Nicolas; Kuster, Niels

    2013-01-01

    Simulating and modelling complex biological systems in computational life sciences requires specialized software tools that can perform medical image data-based modelling, jointly visualize the data and computational results, and handle large, complex, realistic and often noisy anatomical models. The required novel solvers must provide the power to model the physics, biology and physiology of living tissue within the full complexity of the human anatomy (e.g. neuronal activity, perfusion and ultrasound propagation). A multi-physics simulation platform satisfying these requirements has been developed for applications including device development and optimization, safety assessment, basic research, and treatment planning. This simulation platform consists of detailed, parametrized anatomical models, a segmentation and meshing tool, a wide range of solvers and optimizers, a framework for the rapid development of specialized and parallelized finite element method solvers, a visualization toolkit-based visualization engine, a Python scripting interface for customized applications, a coupling framework, and more. Core components are cross-platform compatible and use open formats. Several examples of applications are presented: hyperthermia cancer treatment planning, tumour growth modelling, evaluating the magneto-haemodynamic effect as a biomarker and physics-based morphing of anatomical models. PMID:24427518

  16. An adaptive control volume finite element method for simulation of multi-scale flow in heterogeneous porous media

    NASA Astrophysics Data System (ADS)

    Mostaghimi, P.; Percival, J. R.; Pavlidis, D.; Gorman, G.; Jackson, M.; Neethling, S.; Pain, C. C.

    2013-12-01

    Numerical simulation of multiphase flow in porous media is of importance in a wide range of applications in science and engineering. We present a novel control volume finite element method (CVFEM) to solve for multi-scale flow in heterogeneous geological formations. It employs a node centred control volume approach to discretize the saturation equation, while a control volume finite element method is applied for the pressure equation. We embed the discrete continuity equation into the pressure equation and assure that the continuity is exactly enforced. Anisotropic mesh adaptivity is used to accurately model the fine grained features of multiphase flow. The adaptive algorithm uses a metric tensor field based on solution error estimates to locally control the size and shape of elements in the metric. Moreover, it uses metric advection between adaptive meshes in order to predict the future required density of mesh thereby reducing numerical dispersion at the saturation front. The scheme is capable of capturing multi-scale heterogeneity such as those in fractured porous media through the use of several constraints on the element size in different regions of porous media. We show the application of our method for simulation of flow in some challenging benchmark problems. For flow in fractured reservoirs, the scheme adapts the mesh as the flow penetrates through the fracture and the matrix. The constraints for the element size within the fracture are smaller by several orders of magnitude than the generated mesh within the matrix. We show that the scheme captures the key multi-scale features of flow while preserving the geometry. We demonstrate that mesh adaptation can be used to accurately simulate flow in heterogeneous porous media at low computational cost.

  17. A Monte Carlo simulation based two-stage adaptive resonance theory mapping approach for offshore oil spill vulnerability index classification.

    PubMed

    Li, Pu; Chen, Bing; Li, Zelin; Zheng, Xiao; Wu, Hongjing; Jing, Liang; Lee, Kenneth

    2014-09-15

    In this paper, a Monte Carlo simulation based two-stage adaptive resonance theory mapping (MC-TSAM) model was developed to classify a given site into distinguished zones representing different levels of offshore Oil Spill Vulnerability Index (OSVI). It consisted of an adaptive resonance theory (ART) module, an ART Mapping module, and a centroid determination module. Monte Carlo simulation was integrated with the TSAM approach to address uncertainties that widely exist in site conditions. The applicability of the proposed model was validated by classifying a large coastal area, which was surrounded by potential oil spill sources, based on 12 features. Statistical analysis of the results indicated that the classification process was affected by multiple features instead of one single feature. The classification results also provided the least or desired number of zones which can sufficiently represent the levels of offshore OSVI in an area under uncertainty and complexity, saving time and budget in spill monitoring and response.

  18. Laser pulse design using optimal control theory-based adaptive simulated annealing technique: vibrational transitions and photo-dissociation

    NASA Astrophysics Data System (ADS)

    Nath, Bikram; Mondal, Chandan Kumar

    2014-08-01

    We have designed and optimised a combined laser pulse using optimal control theory-based adaptive simulated annealing technique for selective vibrational excitations and photo-dissociation. Since proper choice of pulses for specific excitation and dissociation phenomena is very difficult, we have designed a linearly combined pulse for such processes and optimised the different parameters involved in those pulses so that we can get an efficient combined pulse. The technique makes us free from choosing any arbitrary type of pulses and makes a ground to check their suitability. We have also emphasised on how we can improve the performance of simulated annealing technique by introducing an adaptive step length of the different variables during the optimisation processes. We have also pointed out on how we can choose the initial temperature for the optimisation process by introducing heating/cooling step to reduce the annealing steps so that the method becomes cost effective.

  19. Effect of three resuscitation procedures on respiratory and metabolic adaptation to extra uterine life in newborn calves.

    PubMed

    Uystepruyst, Ch; Coghe, J; Dorts, Th; Harmegnies, N; Delsemme, M-H; Art, T; Lekeux, P

    2002-01-01

    The purpose of this study was to evaluate the effects of three resuscitation procedures on respiratory and metabolic adaptation to extra-uterine life during the first 24 h after birth in healthy newborn calves. Twenty-four newborn calves were randomly grouped into four categories: six calves did not receive any specific resuscitation procedure and were considered as controls (C); six received pharyngeal and nasal suctioning immediately after birth by use of a hand-powered vacuum pump (SUC); six received five litres of cold water poured over their heads immediately after birth (CW) and six were housed in a calf pen with an infrared radiant heater for 24 h after birth (IR). Calves were examined at birth, 5, 15, 30, 45 and 60 min, 2, 3, 6, 12 and 24 h after birth and the following measurements were recorded: physical and clinical examination, arterial blood gas analysis, pulmonary function tests using the oesophageal balloon catheter technique, arterial and venous blood acid-base balance analysis, jugular venous blood sampling for determination of metabolic, haematological and passive immune transfer variables. SUC was accompanied by improved pulmonary function efficiency and by a less pronounced decrease in body temperature. The "head shaking movement" and the subsequent temporary increase in total pulmonary resistance as well as the greater lactic acidosis due to CW were accompanied by more efficient, but statistically non-significant, pulmonary gas exchanges. IR allowed maintenance of higher body temperature without requiring increased catabolism of energetic stores. IR also caused a change in breathing pattern which contributed to better distribution of the ventilation and to slightly improved gas exchange. The results indicate that use of SUC, CW and IR modified respiratory and metabolic adaptation during the first 24 h after birth without side-effects. These resuscitation procedures should be recommended for their specific indication, i.e. cleansing of fetal

  20. Adapting a Face-to-Face Role-Playing Simulation for Online Play

    ERIC Educational Resources Information Center

    Bos, Nathan; Shami, N. Sadat

    2006-01-01

    The rapid acceleration of online course offerings presents a design challenge for instructors who want to take materials developed for face-to-face settings and adapt them for asynchronous online usage. Broadcast lectures are relatively easy to transfer, but adapting content is harder when classes use small-group discussions, as in role-playing or…

  1. A mathematical model of neuromuscular adaptation to resistance training and its application in a computer simulation of accommodating loads.

    PubMed

    Arandjelović, Ognjen

    2010-10-01

    A large corpus of data obtained by means of empirical study of neuromuscular adaptation is currently of limited use to athletes and their coaches. One of the reasons lies in the unclear direct practical utility of many individual trials. This paper introduces a mathematical model of adaptation to resistance training, which derives its elements from physiological fundamentals on the one side, and empirical findings on the other. The key element of the proposed model is what is here termed the athlete's capability profile. This is a generalization of length and velocity dependent force production characteristics of individual muscles, to an exercise with arbitrary biomechanics. The capability profile, a two-dimensional function over the capability plane, plays the central role in the proposed model of the training-adaptation feedback loop. Together with a dynamic model of resistance the capability profile is used in the model's predictive stage when exercise performance is simulated using a numerical approximation of differential equations of motion. Simulation results are used to infer the adaptational stimulus, which manifests itself through a fed back modification of the capability profile. It is shown how empirical evidence of exercise specificity can be formulated mathematically and integrated in this framework. A detailed description of the proposed model is followed by examples of its application-new insights into the effects of accommodating loading for powerlifting are demonstrated. This is followed by a discussion of the limitations of the proposed model and an overview of avenues for future work.

  2. Health Related Quality of Life of Adolescents in Vietnam: Cross-Cultural Adaptation and Validation of the Adolescent Duke Health Profile

    ERIC Educational Resources Information Center

    Thi Xuan Hanh, Vo; Guillemin, Francis; Dinh Cong, Duong; Parkerson, George R., Jr.; Bach Thu, Pham; Tu Quynh, Pham; Briancon, Serge

    2005-01-01

    Quality of life (QOL) of adolescents has been scarcely documented in a general population sample. The study was aimed at translating and adapting the Adolescent Duke Health Profile to Vietnamese, validating the questionnaire, determining reference value, and identifying determinants of poor QOL. Following a cross-cultural methodology, the…

  3. [Complex estimation of the state of health, quality of life, level of psychological adaptation and rates of senescence of war veterans, suffering from arterial hypertension].

    PubMed

    Zakharova, N O; Iakovlev, O G; Treneva, E V

    2014-01-01

    The article presents some aspects of the health status of the veterans of the Samara region. Intercommunication is marked between the level of social adaptation, quality of life and rate aging combatants. The study shows the effect of chronic posttraumatic stress disorder on the occurrence of psychosomatic pathology and development of senescence combat veterans suffering from arterial hypertension.

  4. Numerical simulation of a Richtmyer-Meshkov instability with an adaptive central-upwind sixth-order WENO scheme

    NASA Astrophysics Data System (ADS)

    Tritschler, V. K.; Hu, X. Y.; Hickel, S.; Adams, N. A.

    2013-07-01

    Two-dimensional simulations of the single-mode Richtmyer-Meshkov instability (RMI) are conducted and compared to experimental results of Jacobs and Krivets (2005 Phys. Fluids 17 034105). The employed adaptive central-upwind sixth-order weighted essentially non-oscillatory (WENO) scheme (Hu et al 2010 J. Comput. Phys. 229 8952-65) introduces only very small numerical dissipation while preserving the good shock-capturing properties of other standard WENO schemes. Hence, it is well suited for simulations with both small-scale features and strong gradients. A generalized Roe average is proposed to make the multicomponent model of Shyue (1998 J. Comput. Phys. 142 208-42) suitable for high-order accurate reconstruction schemes. A first sequence of single-fluid simulations is conducted and compared to the experiment. We find that the WENO-CU6 method better resolves small-scale structures, leading to earlier symmetry breaking and increased mixing. The first simulation, however, fails to correctly predict the global characteristic structures of the RMI. This is due to a mismatch of the post-shock parameters in single-fluid simulations when the pre-shock states are matched with the experiment. When the post-shock parameters are matched, much better agreement with the experimental data is achieved. In a sequence of multifluid simulations, the uncertainty in the density gradient associated with transition between the fluids is assessed. Thereby the multifluid simulations show a considerable improvement over the single-fluid simulations.

  5. Proactive monitoring and adaptive management of social carrying capacity in Arches National Park: an application of computer simulation modeling.

    PubMed

    Lawson, Steven R; Manning, Robert E; Valliere, William A; Wang, Benjamin

    2003-07-01

    Public visits to parks and protected areas continue to increase and may threaten the integrity of natural and cultural resources and the quality of the visitor experience. Scientists and managers have adopted the concept of carrying capacity to address the impacts of visitor use. In the context of outdoor recreation, the social component of carrying capacity refers to the level of visitor use that can be accommodated in parks and protected areas without diminishing the quality of the visitor experience to an unacceptable degree. This study expands and illustrates the use of computer simulation modeling as a tool for proactive monitoring and adaptive management of social carrying capacity at Arches National Park. A travel simulation model of daily visitor use throughout the Park's road and trail network and at selected attraction sites was developed, and simulations were conducted to estimate a daily social carrying capacity for Delicate Arch, an attraction site in Arches National Park, and for the Park as a whole. Further, a series of simulations were conducted to estimate the effect of a mandatory shuttle bus system on daily social carrying capacity of Delicate Arch to illustrate how computer simulation modeling can be used as a tool to facilitate adaptive management of social carrying capacity.

  6. Regional-scale yield simulations using crop and climate models: assessing uncertainties, sensitivity to temperature and adaptation options

    NASA Astrophysics Data System (ADS)

    Challinor, A. J.

    2010-12-01

    Recent progress in assessing the impacts of climate variability and change on crops using multiple regional-scale simulations of crop and climate (i.e. ensembles) is presented. Simulations for India and China used perturbed responses to elevated carbon dioxide constrained using observations from FACE studies and controlled environments. Simulations with crop parameter sets representing existing and potential future adapted varieties were also carried out. The results for India are compared to sensitivity tests on two other crop models. For China, a parallel approach used socio-economic data to account for autonomous farmer adaptation. Results for the USA analysed cardinal temperatures under a range of local warming scenarios for 2711 varieties of spring wheat. The results are as follows: 1. Quantifying and reducing uncertainty. The relative contribution of uncertainty in crop and climate simulation to the total uncertainty in projected yield changes is examined. The observational constraints from FACE and controlled environment studies are shown to be the likely critical factor in maintaining relatively low crop parameter uncertainty. Without these constraints, crop simulation uncertainty in a doubled CO2 environment would likely be greater than uncertainty in simulating climate. However, consensus across crop models in India varied across different biophysical processes. 2. The response of yield to changes in local mean temperature was examined and compared to that found in the literature. No consistent response to temperature change was found across studies. 3. Implications for adaptation. China. The simulations of spring wheat in China show the relative importance of tolerance to water and heat stress in avoiding future crop failures. The greatest potential for reducing the number of harvests less than one standard deviation below the baseline mean yield value comes from alleviating water stress; the greatest potential for reducing harvests less than two

  7. Career Adapt-Abilities Scale--Italian Form: Psychometric Properties and Relationships to Breadth of Interests, Quality of Life, and Perceived Barriers

    ERIC Educational Resources Information Center

    Soresi, Salvatore; Nota, Laura; Ferrari, Lea

    2012-01-01

    The Career Adapt-Abilities Scale (CAAS)-Italian Form consists of four 6-item scales, which measure concern, control, curiosity, and confidence as psychosocial resources for managing occupational transitions, developmental tasks, and work traumas. The 24-item CAAS-Italian Form is identical to the International Form 2.0. The factor structure was…

  8. A comparative study of cold- and warm-adapted Endonucleases A using sequence analyses and molecular dynamics simulations.

    PubMed

    Michetti, Davide; Brandsdal, Bjørn Olav; Bon, Davide; Isaksen, Geir Villy; Tiberti, Matteo; Papaleo, Elena

    2017-01-01

    The psychrophilic and mesophilic endonucleases A (EndA) from Aliivibrio salmonicida (VsEndA) and Vibrio cholera (VcEndA) have been studied experimentally in terms of the biophysical properties related to thermal adaptation. The analyses of their static X-ray structures was no sufficient to rationalize the determinants of their adaptive traits at the molecular level. Thus, we used Molecular Dynamics (MD) simulations to compare the two proteins and unveil their structural and dynamical differences. Our simulations did not show a substantial increase in flexibility in the cold-adapted variant on the nanosecond time scale. The only exception is a more rigid C-terminal region in VcEndA, which is ascribable to a cluster of electrostatic interactions and hydrogen bonds, as also supported by MD simulations of the VsEndA mutant variant where the cluster of interactions was introduced. Moreover, we identified three additional amino acidic substitutions through multiple sequence alignment and the analyses of MD-based protein structure networks. In particular, T120V occurs in the proximity of the catalytic residue H80 and alters the interaction with the residue Y43, which belongs to the second coordination sphere of the Mg2+ ion. This makes T120V an amenable candidate for future experimental mutagenesis.

  9. A comparative study of cold- and warm-adapted Endonucleases A using sequence analyses and molecular dynamics simulations

    PubMed Central

    Michetti, Davide; Brandsdal, Bjørn Olav; Bon, Davide; Isaksen, Geir Villy; Tiberti, Matteo; Papaleo, Elena

    2017-01-01

    The psychrophilic and mesophilic endonucleases A (EndA) from Aliivibrio salmonicida (VsEndA) and Vibrio cholera (VcEndA) have been studied experimentally in terms of the biophysical properties related to thermal adaptation. The analyses of their static X-ray structures was no sufficient to rationalize the determinants of their adaptive traits at the molecular level. Thus, we used Molecular Dynamics (MD) simulations to compare the two proteins and unveil their structural and dynamical differences. Our simulations did not show a substantial increase in flexibility in the cold-adapted variant on the nanosecond time scale. The only exception is a more rigid C-terminal region in VcEndA, which is ascribable to a cluster of electrostatic interactions and hydrogen bonds, as also supported by MD simulations of the VsEndA mutant variant where the cluster of interactions was introduced. Moreover, we identified three additional amino acidic substitutions through multiple sequence alignment and the analyses of MD-based protein structure networks. In particular, T120V occurs in the proximity of the catalytic residue H80 and alters the interaction with the residue Y43, which belongs to the second coordination sphere of the Mg2+ ion. This makes T120V an amenable candidate for future experimental mutagenesis. PMID:28192428

  10. Analysis of adaptive mesh refinement for IMEX discontinuous Galerkin solutions of the compressible Euler equations with application to atmospheric simulations

    NASA Astrophysics Data System (ADS)

    Kopera, Michal A.; Giraldo, Francis X.

    2014-10-01

    The resolutions of interests in atmospheric simulations require prohibitively large computational resources. Adaptive mesh refinement (AMR) tries to mitigate this problem by putting high resolution in crucial areas of the domain. We investigate the performance of a tree-based AMR algorithm for the high order discontinuous Galerkin method on quadrilateral grids with non-conforming elements. We perform a detailed analysis of the cost of AMR by comparing this to uniform reference simulations of two standard atmospheric test cases: density current and rising thermal bubble. The analysis shows up to 15 times speed-up of the AMR simulations with the cost of mesh adaptation below 1% of the total runtime. We pay particular attention to the implicit-explicit (IMEX) time integration methods and show that the ARK2 method is more robust with respect to dynamically adapting meshes than BDF2. Preliminary analysis of preconditioning reveals that it can be an important factor in the AMR overhead. The compiler optimizations provide significant runtime reduction and positively affect the effectiveness of AMR allowing for speed-ups greater than it would follow from the simple performance model.

  11. Comparative transcriptomics of two pathogenic pinewood nematodes yields insights into parasitic adaptation to life on pine hosts.

    PubMed

    Yan, Xia; Cheng, Xin-Yue; Wang, Yun-Sheng; Luo, Ji; Mao, Zhen-Chuan; Ferris, Virginia R; Xie, Bing-Yan

    2012-08-15

    Bursaphelenchus xylophilus and Bursaphelenchus mucronatus are migratory endoparasitic nematodes that live in pine trees. To gain insight into their molecular similarities and differences, transcriptomes of the two nematodes were analysed. A total of 23,765 and 21,782 contigs (>300 bp) were obtained from B. xylophilus and B. mucronatus, respectively. More than 80% of the contigs could map to each other's transcriptome reciprocally. A total of 23,467 and 21,370 Open Reading Frames were predicted, respectively. Besides those known parasitism-related proteins, six new venom allergen-like proteins (VAPs) were found, which were not homologous to known VAPs. Enzymes involved in xenobiotic biodegradation were abundant in the two transcriptomes based on KEGG functional annotation. Metabolism of xenobiotics by cytochrome P450 comprised the main detoxification pathways. The mRNA expression levels of detoxification genes in nematodes living in the host were higher than those in nematodes feeding on fungus. However, there were fewer enzymes involved in the α-pinene degradation. Our results indicate that the two pinewood nematodes have evolved similar molecular mechanisms to adapt to life on pine hosts.

  12. Evolutionary implications of the adaptation to different immune systems in a parasite with a complex life cycle.

    PubMed

    Hammerschmidt, Katrin; Kurtz, Joachim

    2005-12-07

    Many diseases are caused by parasites with complex life cycles that involve several hosts. If parasites cope better with only one of the different types of immune systems of their host species, we might expect a trade-off in parasite performance in the different hosts, that likely influences the evolution of virulence. We tested this hypothesis in a naturally co-evolving host-parasite system consisting of the tapeworm Schistocephalus solidus and its intermediate hosts, a copepod, Macrocyclops albidus, and the three-spined stickleback Gasterosteus aculeatus. We did not find a trade-off between infection success in the two hosts. Rather, tapeworms seem to trade-off adaptation towards different parts of their hosts' immune systems. Worm sibships that performed better in the invertebrate host also seem to be able to evade detection by the fish innate defence systems, i.e. induce lower levels of activation of innate immune components. These worm variants were less harmful for the fish host likely due to reduced costs of an activated innate immune system. These findings substantiate the impact of both hosts' immune systems on parasite performance and virulence.

  13. Evolutionary implications of the adaptation to different immune systems in a parasite with a complex life cycle

    PubMed Central

    Hammerschmidt, Katrin; Kurtz, Joachim

    2005-01-01

    Many diseases are caused by parasites with complex life cycles that involve several hosts. If parasites cope better with only one of the different types of immune systems of their host species, we might expect a trade-off in parasite performance in the different hosts, that likely influences the evolution of virulence. We tested this hypothesis in a naturally co-evolving host–parasite system consisting of the tapeworm Schistocephalus solidus and its intermediate hosts, a copepod, Macrocyclops albidus, and the three-spined stickleback Gasterosteus aculeatus. We did not find a trade-off between infection success in the two hosts. Rather, tapeworms seem to trade-off adaptation towards different parts of their hosts' immune systems. Worm sibships that performed better in the invertebrate host also seem to be able to evade detection by the fish innate defence systems, i.e. induce lower levels of activation of innate immune components. These worm variants were less harmful for the fish host likely due to reduced costs of an activated innate immune system. These findings substantiate the impact of both hosts' immune systems on parasite performance and virulence. PMID:16271977

  14. Machine remaining useful life prediction: An integrated adaptive neuro-fuzzy and high-order particle filtering approach

    NASA Astrophysics Data System (ADS)

    Chen, Chaochao; Vachtsevanos, George; Orchard, Marcos E.

    2012-04-01

    Machine prognosis can be considered as the generation of long-term predictions that describe the evolution in time of a fault indicator, with the purpose of estimating the remaining useful life (RUL) of a failing component/subsystem so that timely maintenance can be performed to avoid catastrophic failures. This paper proposes an integrated RUL prediction method using adaptive neuro-fuzzy inference systems (ANFIS) and high-order particle filtering, which forecasts the time evolution of the fault indicator and estimates the probability density function (pdf) of RUL. The ANFIS is trained and integrated in a high-order particle filter as a model describing the fault progression. The high-order particle filter is used to estimate the current state and carry out p-step-ahead predictions via a set of particles. These predictions are used to estimate the RUL pdf. The performance of the proposed method is evaluated via the real-world data from a seeded fault test for a UH-60 helicopter planetary gear plate. The results demonstrate that it outperforms both the conventional ANFIS predictor and the particle-filter-based predictor where the fault growth model is a first-order model that is trained via the ANFIS.

  15. The LISA Pathfinder Simulator for the Science and Technology Operations Center: Simulator Reuse Across the Project Life-Cycle: Practical Experiences and Lessons Learned

    NASA Astrophysics Data System (ADS)

    van der Plas, Peter; Leorato, Christiano

    2010-08-01

    During the operational phase of the Lisa Pathfinder (LPF) mission, the Science and Technology Operations Center (STOC) will be in charge of the operations of the LPF experiments. For the STOC to be able to perform its planning activities, an experiment simulator is required. The STOC simulator is based on the reuse of two simulators, which had originally been developed by EADS Astrium to support previous phases of the project life-cycle. This paper describes the STOC Simulator development approach, the used technologies and the high-level design. It then focuses on the specific implications of the reuse of the existing simulators: relevant issues are highlighted, together with the adopted solutions. Finally, the paper reports the first feedback on the actual usage of the STOC Simulator and then summarizes the lessons learned.

  16. Stress Recovery Based h-Adaptive Finite Element Simulation of Sheet Forming Operations

    NASA Astrophysics Data System (ADS)

    Ahmed, Mohd.; Singh, Devinder

    2016-07-01

    In the present work, stress recovery techniques based adaptive finite element analysis of sheet forming operations is presented. An adaptive two dimensional finite element computer code allows the analysis of sheet forming operations and results in distribution of adaptively refined mesh, effective strain, and punch load, stress and strain rate tensor in the domain that has been developed. The recovery scheme for determining more accurate stress field is based on the least squares fitting of the computed stresses in an element patch surrounding and including a particular node. The solution error is estimated on the basis of an energy norm. It is shown with the help of an illustrative example of axi-symmetric stretching of a metal blank by a hemispherical punch that the adaptive analysis may be usefully employed to predict accurately deformation process, the seats of large deformations and locations of possible instability.

  17. Productive confusions: learning from simulations of pandemic virus outbreaks in Second Life

    NASA Astrophysics Data System (ADS)

    Cárdenas, Micha; Greci, Laura S.; Hurst, Samantha; Garman, Karen; Hoffman, Helene; Huang, Ricky; Gates, Michael; Kho, Kristen; Mehrmand, Elle; Porteous, Todd; Calvitti, Alan; Higginbotham, Erin; Agha, Zia

    2011-03-01

    Users of immersive virtual reality environments have reported a wide variety of side and after effects including the confusion of characteristics of the real and virtual worlds. Perhaps this side effect of confusing the virtual and real can be turned around to explore the possibilities for immersion with minimal technological support in virtual world group training simulations. This paper will describe observations from my time working as an artist/researcher with the UCSD School of Medicine (SoM) and Veterans Administration San Diego Healthcare System (VASDHS) to develop trainings for nurses, doctors and Hospital Incident Command staff that simulate pandemic virus outbreaks. By examining moments of slippage between realities, both into and out of the virtual environment, moments of the confusion of boundaries between real and virtual, we can better understand methods for creating immersion. I will use the mixing of realities as a transversal line of inquiry, borrowing from virtual reality studies, game studies, and anthropological studies to better understand the mechanisms of immersion in virtual worlds. Focusing on drills conducted in Second Life, I will examine moments of training to learn the software interface, moments within the drill and interviews after the drill.

  18. A comparison between the 2010 and 2005 basic life support guidelines during simulated hypogravity and microgravity

    PubMed Central

    2013-01-01

    Background Current 2010 terrestrial (1Gz) CPR guidelines have been advocated by space agencies for hypogravity and microgravity environments, but may not be feasible. The aims of this study were to (1) evaluate rescuer performance over 1.5 min of external chest compressions (ECCs) during simulated Martian hypogravity (0.38Gz) and microgravity (μG) in relation to 1Gz and rest baseline and (2) compare the physiological costs of conducting ECCs in accordance with the 2010 and 2005 CPR guidelines. Methods Thirty healthy male volunteers, ranging from 17 to 30 years, performed four sets of 30 ECCs for 1.5 min using the 2010 and 2005 ECC guidelines during 1Gz, 0.38Gz and μG simulations (Evetts-Russomano (ER) method), achieved by the use of a body suspension device. ECC depth and rate, range of elbow flexion, post-ECC heart rate (HR), minute ventilation (VE), peak oxygen consumption (VO2peak) and rate of perceived exertion (RPE) were measured. Results All volunteers completed the study. Mean ECC rate was achieved for all gravitational conditions, but true depth during simulated microgravity was not sufficient for the 2005 (28.5 ± 7.0 mm) and 2010 (32.9 ± 8.7 mm) guidelines, even with a mean range of elbow flexion of 15°. HR, VE and VO2peak increased to an average of 136 ± 22 bpm, 37.5 ± 10.3 L·min−1, 20.5 ± 7.6 mL·kg−1·min−1 for 0.38Gz and 161 ± 19 bpm, 58.1 ± 15.0 L·min−1, 24.1 ± 5.6 mL·kg−1·min−1 for μG from a baseline of 84 ± 15 bpm, 11.4 ± 5.9 L·min−1, 3.2 ± 1.1 mL·kg−1·min-1, respectively. RPE was the only variable to increase with the 2010 guidelines. Conclusion No additional physiological cost using the 2010 basic life support (BLS) guidelines was needed for healthy males performing ECCs for 1.5 min, independent of gravitational environment. This cost, however, increased for each condition tested when the two guidelines were compared. Effective ECCs were not achievable for both guidelines in simulated μG using the ER BLS

  19. Mortality sensitivity in life-stage simulation analysis: A case study of southern sea otters

    USGS Publications Warehouse

    Gerber, L.R.; Tinker, M.T.; Doak, D.F.; Estes, J.A.; Jessup, David A.

    2004-01-01

    Currently, there are no generally recognized approaches for linking detailed mortality and pathology data to population-level analyses of extinction risk. We used a combination of analytical and simulation-based analyses to examine 20 years of age- and sex-specific mortality data for southern sea otters (Enhydra lutris), and we applied results to project the efficacy of alternative conservation strategies. Population recovery of the southern sea otter has been slow (rate of population increase ?? = 1.05) compared to other recovering populations (?? = 1.17-1.20), and the population declined (?? = 0.975) between 1995 and 1999. Age-based Leslie matrices were developed to explore explanations for the slow recovery and recent decline in the southern sea other population. An elasticity analysis was performed to predict effects of proportional changes in stage-specific reproductive or survival rates on the rate of population increase. A life-stage simulation analysis (LSA) was developed to evaluate the impact of changing age- and cause-specific mortality rates on ??. The information used to develop these models was derived from death assemblage, pathology, and live population census data to examine the sensitivity of sea otter population growth to different sources of mortality (e.g., disease and starvation, direct human take [fisheries, gun shot, boat strike, oil pollution], mating trauma and intraspecific aggression, shark bites, and unknown). We used resampling simulations to generate random combinations of vital rates for a large number of matrix replicates and drew on these to estimate potential effects of mortality sources on population growth (??). Our analyses suggest management actions that are likely and unlikely to promote recovery of the southern sea otter and more broadly indicate a methodology to better utilize cause-of-death data in conservation decision-making.

  20. Adaptive-mesh-refinement simulation of partial coalescence cascade of a droplet at a liquid-liquid interface

    NASA Astrophysics Data System (ADS)

    Fakhari, Abbas; Bolster, Diogo

    2016-11-01

    A three-dimensional (3D) adaptive mesh refinement (AMR) algorithm on structured Cartesian grids is developed, and supplemented by a mesoscopic multiphase-flow solver based on state-of-the-art lattice Boltzmann methods (LBM). Using this in-house AMR-LBM routine, we present fully 3D simulations of partial coalescence of a liquid drop with an initially flat interface at small Ohnesorge and Bond numbers. Qualitatively, our numerical simulations are in excellent agreement with experimental observations. Partial coalescence cascades are successfully observed at very small Ohnesorge numbers (Oh 10-4). The fact that the partial coalescence is absent in similar 2D simulations suggests that the Rayleigh-Plateau instability may be the principle driving mechanism responsible for this phenomenon.

  1. Simulation model based approach for long exposure atmospheric point spread function reconstruction for laser guide star multiconjugate adaptive optics.

    PubMed

    Gilles, Luc; Correia, Carlos; Véran, Jean-Pierre; Wang, Lianqi; Ellerbroek, Brent

    2012-11-01

    This paper discusses an innovative simulation model based approach for long exposure atmospheric point spread function (PSF) reconstruction in the context of laser guide star (LGS) multiconjugate adaptive optics (MCAO). The approach is inspired from the classical scheme developed by Véran et al. [J. Opt. Soc. Am. A14, 3057 (1997)] and Flicker et al. [Astron. Astrophys.400, 1199 (2003)] and reconstructs the long exposure optical transfer function (OTF), i.e., the Fourier transformed PSF, as a product of separate long-exposure tip/tilt removed and tip/tilt OTFs, each estimated by postprocessing system and simulation telemetry data. Sample enclosed energy results assessing reconstruction accuracy are presented for the Thirty Meter Telescope LGS MCAO system currently under design and show that percent level absolute and differential photometry over a 30 arcsec diameter field of view are achievable provided the simulation model faithfully represents the real system.

  2. N-body simulations for f(R) gravity using a self-adaptive particle-mesh code

    SciTech Connect

    Zhao Gongbo; Koyama, Kazuya; Li Baojiu

    2011-02-15

    We perform high-resolution N-body simulations for f(R) gravity based on a self-adaptive particle-mesh code MLAPM. The chameleon mechanism that recovers general relativity on small scales is fully taken into account by self-consistently solving the nonlinear equation for the scalar field. We independently confirm the previous simulation results, including the matter power spectrum, halo mass function, and density profiles, obtained by Oyaizu et al.[Phys. Rev. D 78, 123524 (2008)] and Schmidt et al.[Phys. Rev. D 79, 083518 (2009)], and extend the resolution up to k{approx}20 h/Mpc for the measurement of the matter power spectrum. Based on our simulation results, we discuss how the chameleon mechanism affects the clustering of dark matter and halos on full nonlinear scales.

  3. Covert rapid action-memory simulation (CRAMS): A hypothesis of hippocampal-prefrontal interactions for adaptive behavior

    PubMed Central

    Wang, Jane X.; Cohen, Neal J.; Voss, Joel L.

    2014-01-01

    Effective choices generally require memory, yet little is known regarding the cognitive or neural mechanisms that allow memory to influence choices. We outline a new framework proposing that covert memory processing of hippocampus interacts with action-generation processing of prefrontal cortex in order to arrive at optimal, memory-guided choices. Covert, rapid action-memory simulation (CRAMS) is proposed here as a framework for understanding cognitive and/or behavioral choices, whereby prefrontal-hippocampal interactions quickly provide multiple simulations of potential outcomes used to evaluate the set of possible choices. We hypothesize that this CRAMS process is automatic, obligatory, and covert, meaning that many cycles of action-memory simulation occur in response to choice conflict without an individual’s necessary intention and generally without awareness of the simulations, leading to adaptive behavior with little perceived effort. CRAMS is thus distinct from influential proposals that adaptive memory-based behavior in humans requires consciously experienced memory-based construction of possible future scenarios and deliberate decisions among possible future constructions. CRAMS provides an account of why hippocampus has been shown to make critical contributions to the short-term control of behavior, and it motivates several new experimental approaches and hypotheses that could be used to better understand the ubiquitous role of prefrontal-hippocampal interactions in situations that require adaptively using memory to guide choices. Importantly, this framework provides a perspective that allows for testing decision-making mechanisms in a manner that translates well across human and nonhuman animal model systems. PMID:24752152

  4. Temperature structure of the intracluster medium from smoothed-particle hydrodynamics and adaptive-mesh refinement simulations

    SciTech Connect

    Rasia, Elena; Lau, Erwin T.; Nagai, Daisuke; Avestruz, Camille; Borgani, Stefano; Dolag, Klaus; Granato, Gian Luigi; Murante, Giuseppe; Ragone-Figueroa, Cinthia; Mazzotta, Pasquale; Nelson, Kaylea

    2014-08-20

    Analyses of cosmological hydrodynamic simulations of galaxy clusters suggest that X-ray masses can be underestimated by 10%-30%. The largest bias originates from both violation of hydrostatic equilibrium (HE) and an additional temperature bias caused by inhomogeneities in the X-ray-emitting intracluster medium (ICM). To elucidate this large dispersion among theoretical predictions, we evaluate the degree of temperature structures in cluster sets simulated either with smoothed-particle hydrodynamics (SPH) or adaptive-mesh refinement (AMR) codes. We find that the SPH simulations produce larger temperature variations connected to the persistence of both substructures and their stripped cold gas. This difference is more evident in nonradiative simulations, whereas it is reduced in the presence of radiative cooling. We also find that the temperature variation in radiative cluster simulations is generally in agreement with that observed in the central regions of clusters. Around R {sub 500} the temperature inhomogeneities of the SPH simulations can generate twice the typical HE mass bias of the AMR sample. We emphasize that a detailed understanding of the physical processes responsible for the complex thermal structure in ICM requires improved resolution and high-sensitivity observations in order to extend the analysis to higher temperature systems and larger cluster-centric radii.

  5. Particle Swarm Social Adaptive Model for Multi-Agent Based Insurgency Warfare Simulation

    SciTech Connect

    Cui, Xiaohui; Potok, Thomas E

    2009-12-01

    To better understand insurgent activities and asymmetric warfare, a social adaptive model for modeling multiple insurgent groups attacking multiple military and civilian targets is proposed and investigated. This report presents a pilot study using the particle swarm modeling, a widely used non-linear optimal tool to model the emergence of insurgency campaign. The objective of this research is to apply the particle swarm metaphor as a model of insurgent social adaptation for the dynamically changing environment and to provide insight and understanding of insurgency warfare. Our results show that unified leadership, strategic planning, and effective communication between insurgent groups are not the necessary requirements for insurgents to efficiently attain their objective.

  6. A fully implicit, fully adaptive time and space discretisation method for phase-field simulation of binary alloy solidification

    NASA Astrophysics Data System (ADS)

    Rosam, J.; Jimack, P. K.; Mullis, A.

    2007-08-01

    A fully implicit numerical method based upon adaptively refined meshes for the simulation of binary alloy solidification in 2D is presented. In addition we combine a second-order fully implicit time discretisation scheme with variable step size control to obtain an adaptive time and space discretisation method. The superiority of this method, compared to widely used fully explicit methods, with respect to CPU time and accuracy, is shown. Due to the high nonlinearity of the governing equations a robust and fast solver for systems of nonlinear algebraic equations is needed to solve the intermediate approximations per time step. We use a nonlinear multigrid solver which shows almost h-independent convergence behaviour.

  7. Brain activity and prosocial behavior in a simulated life-threatening situation.

    PubMed

    Zanon, Marco; Novembre, Giovanni; Zangrando, Nicola; Chittaro, Luca; Silani, Giorgia

    2014-09-01

    To study the neuronal basis of altruistic behavior, we investigated functional connectivity within brain networks of participants who exhibited either a self-benefit behavior or an altruistic one in a life-threatening situation simulated in a virtual environment. In particular, participants were asked to evacuate a virtual building on fire and, without being previously informed, they were faced with a decision on whether to stop and help a trapped virtual human, at the possible cost of losing their own life in the virtual experience. Group independent component analysis (gICA) applied on blood-oxygen-level-dependent (BOLD) functional images revealed significant differences between the group of participants who showed selfish behavior and those who acted prosocially. Specifically, an increased functional connectivity in the salience network, comprising the anterior insula (AI) and the anterior mid cingulate cortex (aMCC), was observed in the selfish group compared to the prosocial one. Conversely, higher ICA weights in the medial prefrontal cortex and temporo-parietal junction (TPJ), were observed in the prosocial group. The findings show that an increased functional connectivity of the salience network, which suggests an enhanced sensitivity to the threatening situation and potential danger for the individual, resulted in more selfish choices, while the engagement of the medial prefrontal and temporo-parietal cortices subserved prosocial behavior, possibly due to their role in perspective-taking. The study provides the first online neurophysiological measurement of prosocial decision-making during threatening situations, opening new avenues to the investigation of neuronal substrates of complex social behaviors.

  8. Report on three Genomes to Life Workshops: Data Infrastructure, Modeling and Simulation, and Protein Structure Prediction

    SciTech Connect

    Geist, GA

    2003-09-16

    On July 22, 23, 24, 2003, three one day workshops were held in Gaithersburg, Maryland. Each was attended by about 30 computational biologists, mathematicians, and computer scientists who were experts in the respective workshop areas The first workshop discussed the data infrastructure needs for the Genomes to Life (GTL) program with the objective to identify gaps in the present GTL data infrastructure and define the GTL data infrastructure required for the success of the proposed GTL facilities. The second workshop discussed the modeling and simulation needs for the next phase of the GTL program and defined how these relate to the experimental data generated by genomics, proteomics, and metabolomics. The third workshop identified emerging technical challenges in computational protein structure prediction for DOE missions and outlining specific goals for the next phase of GTL. The workshops were attended by representatives from both OBER and OASCR. The invited experts at each of the workshops made short presentations on what they perceived as the key needs in the GTL data infrastructure, modeling and simulation, and structure prediction respectively. Each presentation was followed by a lively discussion by all the workshop attendees. The following findings and recommendations were derived from the three workshops. A seamless integration of GTL data spanning the entire range of genomics, proteomics, and metabolomics will be extremely challenging but it has to be treated as the first-class component of the GTL program to assure GTL's chances for success. High-throughput GTL facilities and ultrascale computing will make it possible to address the ultimate goal of modern biology: to achieve a fundamental, comprehensive, and systematic understanding of life. But first the GTL community needs to address the problem of the massive quantities and increased complexity of biological data produced by experiments and computations. Genome-scale collection, analysis

  9. Modeling and Simulation of An Adaptive Neuro-Fuzzy Inference System (ANFIS) for Mobile Learning

    ERIC Educational Resources Information Center

    Al-Hmouz, A.; Shen, Jun; Al-Hmouz, R.; Yan, Jun

    2012-01-01

    With recent advances in mobile learning (m-learning), it is becoming possible for learning activities to occur everywhere. The learner model presented in our earlier work was partitioned into smaller elements in the form of learner profiles, which collectively represent the entire learning process. This paper presents an Adaptive Neuro-Fuzzy…

  10. SIMULATION OF DISPERSION OF A POWER PLANT PLUME USING AN ADAPTIVE GRID ALGORITHM. (R827028)

    EPA Science Inventory

    A new dynamic adaptive grid algorithm has been developed for use in air quality modeling. This algorithm uses a higher order numerical scheme––the piecewise parabolic method (PPM)––for computing advective solution fields; a weight function capable o...

  11. SIMULATION OF DISPERSION OF A POWER PLANT PLUME USING AN ADAPTIVE GRID ALGORITHM

    EPA Science Inventory

    A new dynamic adaptive grid algorithm has been developed for use in air quality modeling. This algorithm uses a higher order numerical scheme?the piecewise parabolic method (PPM)?for computing advective solution fields; a weight function capable of promoting grid node clustering ...

  12. Simulated lumped-parameter system reduced-order adaptive control studies

    NASA Technical Reports Server (NTRS)

    Johnson, C. R., Jr.; Lawrence, D. A.; Taylor, T.; Malakooti, M. V.

    1981-01-01

    Two methods of interpreting the misbehavior of reduced order adaptive controllers are discussed. The first method is based on system input-output description and the second is based on state variable description. The implementation of the single input, single output, autoregressive, moving average system is considered.

  13. ADAPTIVE-GRID SIMULATION OF GROUNDWATER FLOW IN HETEROGENEOUS AQUIFERS. (R825689C068)

    EPA Science Inventory

    Abstract

    The prediction of contaminant transport in porous media requires the computation of the flow velocity. This work presents a methodology for high-accuracy computation of flow in a heterogeneous isotropic formation, employing a dual-flow formulation and adaptive...

  14. Towards Validation of an Adaptive Flight Control Simulation Using Statistical Emulation

    NASA Technical Reports Server (NTRS)

    He, Yuning; Lee, Herbert K. H.; Davies, Misty D.

    2012-01-01

    Traditional validation of flight control systems is based primarily upon empirical testing. Empirical testing is sufficient for simple systems in which a.) the behavior is approximately linear and b.) humans are in-the-loop and responsible for off-nominal flight regimes. A different possible concept of operation is to use adaptive flight control systems with online learning neural networks (OLNNs) in combination with a human pilot for off-nominal flight behavior (such as when a plane has been damaged). Validating these systems is difficult because the controller is changing during the flight in a nonlinear way, and because the pilot and the control system have the potential to co-adapt in adverse ways traditional empirical methods are unlikely to provide any guarantees in this case. Additionally, the time it takes to find unsafe regions within the flight envelope using empirical testing means that the time between adaptive controller design iterations is large. This paper describes a new concept for validating adaptive control systems using methods based on Bayesian statistics. This validation framework allows the analyst to build nonlinear models with modal behavior, and to have an uncertainty estimate for the difference between the behaviors of the model and system under test.

  15. An Evolving Simulation/Gaming Process to Facilitate Adaptive Watershed Management in Northern Mountainous Thailand

    ERIC Educational Resources Information Center

    Barnaud, Cecile; Promburom, Tanya; Trebuil, Guy; Bousquet, Francois

    2007-01-01

    The decentralization of natural resource management provides an opportunity for communities to increase their participation in related decision making. Research should propose adapted methodologies enabling the numerous stakeholders of these complex socioecological settings to define their problems and identify agreed-on solutions. This article…

  16. Development and Simulation Testing of a Computerized Adaptive Version of the Philadelphia Naming Test

    ERIC Educational Resources Information Center

    Hula, William D.; Kellough, Stacey; Fergadiotis, Gerasimos

    2015-01-01

    Purpose: The purpose of this study was to develop a computerized adaptive test (CAT) version of the Philadelphia Naming Test (PNT; Roach, Schwartz, Martin, Grewal, & Brecher, 1996), to reduce test length while maximizing measurement precision. This article is a direct extension of a companion article (Fergadiotis, Kellough, & Hula, 2015),…

  17. SIMCA T 1.0: A SAS Computer Program for Simulating Computer Adaptive Testing

    ERIC Educational Resources Information Center

    Raiche, Gilles; Blais, Jean-Guy

    2006-01-01

    Monte Carlo methodologies are frequently applied to study the sampling distribution of the estimated proficiency level in adaptive testing. These methods eliminate real situational constraints. However, these Monte Carlo methodologies are not currently supported by the available software programs, and when these programs are available, their…

  18. Does Personality Moderate Reaction and Adaptation to Major Life Events? Evidence from the British Household Panel Survey

    PubMed Central

    Yap, Stevie C. Y.; Anusic, Ivana; Lucas, Richard E.

    2012-01-01

    A nationally representative panel study of British households was used to examine the extent to which Big Five personality traits interact with the experience of major life events (marriage, childbirth, unemployment, and widowhood) to predict increases and decreases in life satisfaction following the event. Results show that major life events are associated with changes in life satisfaction, and some of these changes are very long lasting. Personality traits did not have consistent moderating effects on the association between stressful life events and life satisfaction over time. PMID:23049147

  19. High-Fidelity Space-Time Adaptive Multiphysics Simulations in Nuclear Engineering

    SciTech Connect

    Solin, Pavel; Ragusa, Jean

    2014-03-09

    We delivered a series of fundamentally new computational technologies that have the potential to significantly advance the state-of-the-art of computer simulations of transient multiphysics nuclear reactor processes. These methods were implemented in the form of a C++ library, and applied to a number of multiphysics coupled problems relevant to nuclear reactor simulations.

  20. A comparison of adaptive sampling designs and binary spatial models: A simulation study using a census of Bromus inermis

    USGS Publications Warehouse

    Irvine, Kathryn M.; Thornton, Jamie; Backus, Vickie M.; Hohmann, Matthew G.; Lehnhoff, Erik A.; Maxwell, Bruce D.; Michels, Kurt; Rew, Lisa

    2013-01-01

    Commonly in environmental and ecological studies, species distribution data are recorded as presence or absence throughout a spatial domain of interest. Field based studies typically collect observations by sampling a subset of the spatial domain. We consider the effects of six different adaptive and two non-adaptive sampling designs and choice of three binary models on both predictions to unsampled locations and parameter estimation of the regression coefficients (species–environment relationships). Our simulation study is unique compared to others to date in that we virtually sample a true known spatial distribution of a nonindigenous plant species, Bromus inermis. The census of B. inermis provides a good example of a species distribution that is both sparsely (1.9 % prevalence) and patchily distributed. We find that modeling the spatial correlation using a random effect with an intrinsic Gaussian conditionally autoregressive prior distribution was equivalent or superior to Bayesian autologistic regression in terms of predicting to un-sampled areas when strip adaptive cluster sampling was used to survey B. inermis. However, inferences about the relationships between B. inermis presence and environmental predictors differed between the two spatial binary models. The strip adaptive cluster designs we investigate provided a significant advantage in terms of Markov chain Monte Carlo chain convergence when trying to model a sparsely distributed species across a large area. In general, there was little difference in the choice of neighborhood, although the adaptive king was preferred when transects were randomly placed throughout the spatial domain.