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Sample records for adaptation level theory

  1. An Adaptation Level Theory of Tinnitus Audibility

    PubMed Central

    Searchfield, Grant D.; Kobayashi, Kei; Sanders, Michael

    2012-01-01

    Models of tinnitus suggest roles for auditory, attention, and emotional networks in tinnitus perception. A model of tinnitus audibility based on Helson’s (1964) adaptation level theory (ALT) is hypothesized to explain the relationship between tinnitus audibility, personality, memory, and attention. This theory attempts to describe how tinnitus audibility or detectability might change with experience and context. The basis of ALT and potential role of auditory scene analysis in tinnitus perception are discussed. The proposed psychoacoustic model lends itself to incorporation into existing neurophysiological models of tinnitus perception. It is hoped that the ALT hypothesis will allow for greater empirical investigation of factors influencing tinnitus perception, such as attention and tinnitus sound therapies. PMID:22707935

  2. Theory and experimental study on low-light-level images by adaptive mode filter

    NASA Astrophysics Data System (ADS)

    Bai, Lianfa; Zhang, Baomin; Liu, Yunfen; Chen, Qian

    1996-09-01

    Real-time low light level (LLL) image processing technology is the important developmental subject in the area of LLL night vision. But there is an essential distinction between the LLL TV image and ordinary TV image, so the conventional digital image processing technique aren't suitable for LLL image. In this paper, the noise theoretical model of LLL imaging system is described and the LLL image processing system is set up. With regard to the characteristics of LLL image and its noise, a novel noise suppression method, adaptive mode filter, is presented. The experimental results show that the adaptive mode filter can suppress the sharp noise of LLL image effectively, and as for the protection of the image edge, the property of adaptive mode filter is better that of median filter. Finally, the processing results and the conclusions are given.

  3. On Some Possible Links between Personality Theory, Cultural Levels of Adaptation, and Christian Theology.

    ERIC Educational Resources Information Center

    O'Sullivan, Ralph G.

    The purpose of this paper is to link several sets of ideas in personality theory to each other and to Christian theology; link several sets of ideas in personality theory and cultural anthropology to each other and to Christian theology; and demonstrate that various social phenomena are not the domain of any particular social or behavioral science…

  4. Theory of psychological adaptive modes.

    PubMed

    Lehti, Juha

    2016-05-01

    When an individual is facing a stressor and normal stress-response mechanism cannot guarantee sufficient adaptation, special emotional states, adaptive modes, are activated (for example a depressive reaction). Adaptive modes are involuntary states of mind, they are of comprehensive nature, they interfere with normal functioning, and they cannot be repressed or controlled the same way as many emotions. Their transformational nature differentiates them from other emotional states. The object of the adaptive mode is to optimize the problem-solving abilities according to the situation that has provoked the mode. Cognitions and emotions during the adaptive mode are different than in a normal mental state. These altered cognitions and emotional reactions guide the individual to use the correct coping skills in order to deal with the stressor. Successful adaptation will cause the adaptive mode to fade off since the adaptive mode is no longer necessary, and the process as a whole will lead to raised well-being. However, if the adaptation process is inadequate, then the transformation period is prolonged, and the adaptive mode will turn into a dysfunctional state. Many psychiatric disorders are such maladaptive processes. The maladaptive processes can be turned into functional ones by using adaptive skills that are used in functional adaptive processes. PMID:27063089

  5. An adaptive level set method

    SciTech Connect

    Milne, R.B.

    1995-12-01

    This thesis describes a new method for the numerical solution of partial differential equations of the parabolic type on an adaptively refined mesh in two or more spatial dimensions. The method is motivated and developed in the context of the level set formulation for the curvature dependent propagation of surfaces in three dimensions. In that setting, it realizes the multiple advantages of decreased computational effort, localized accuracy enhancement, and compatibility with problems containing a range of length scales.

  6. Applications of adaptive state estimation theory

    NASA Technical Reports Server (NTRS)

    Moose, R. L.; Vanlandingham, H. F.; Mccabe, D. H.

    1980-01-01

    Two main areas of application of adaptive state estimation theory are presented. Following a review of the basic estimation approach, its application to both the control of nonlinear plants and to the problem of tracking maneuvering targets is presented. Results are brought together from these two areas of investigation to provide insight into the wide range of possible applications of the general estimation method.

  7. Adaptive piezoelectric shell structures: theory and experiments

    NASA Astrophysics Data System (ADS)

    Tzou, H. S.; Zhong, J. P.

    1993-07-01

    Active "smart" space and mechanical structures with adaptive dynamic characteristics have long been interested in a variety of high-performance systems, e.g. flexible space structures, flexible robots, "smart" machines etc. In this paper, an active adaptive structure made of piezoelectric materials is proposed and evaluated. Electromechanical equations of motion and generalised boundary conditions of a generic piezoelectric shell subjected to mechanical and electrical excitations are derived using Hamilton's principle and the linear piezoelectric theory. The structural adaptivity is achieved by a voltage feedback (open or closed loops) utilising the converse piezoelectric effect. Applications of the theory is demonstrated in a bimorph beam case and a cylindrical shell case. Frequency manipulation of the bimorph beam is studied theoretically and experimentally. Damping control of the cylindrical shell via in-plane membrane forces is also investigated.

  8. Capturing the superorganism: a formal theory of group adaptation.

    PubMed

    Gardner, A; Grafen, A

    2009-04-01

    Adaptation is conventionally regarded as occurring at the level of the individual organism. However, in recent years there has been a revival of interest in the possibility for group adaptations and superorganisms. Here, we provide the first formal theory of group adaptation. In particular: (1) we clarify the distinction between group selection and group adaptation, framing the former in terms of gene frequency change and the latter in terms of optimization; (2) we capture the superorganism in the form of a 'group as maximizing agent' analogy that links an optimization program to a model of a group-structured population; (3) we demonstrate that between-group selection can lead to group adaptation, but only in rather special circumstances; (4) we provide formal support for the view that between-group selection is the best definition for 'group selection'; and (5) we reveal that mechanisms of conflict resolution such as policing cannot be regarded as group adaptations. PMID:19210588

  9. Demographic evidence for adaptive theories of aging.

    PubMed

    Mitteldorf, J J

    2012-07-01

    Pleiotropic theories for the evolutionary origins of senescence have been ascendant for forty years (see, for example, G. Williams (1957) Evolution, 11, 398-411; T. Kirkwood (1977) Nature, 270, 301-304), and it is not surprising that interpreters of demographic data seek to frame their results in this context. But some of that evidence finds a much more natural explanation in terms of adaptive aging. Here we re-interpret the 1997 results of the Centenarian Study in Boston, which found in their sample of centenarian women an excess of late childbearing. The finding was originally interpreted as a selection effect: a metabolic link between late menopause and longevity. But we demonstrate that this interpretation is statistically strained, and that the data in fact indicate a causal link: bearing a child late in life induces a metabolic response that promotes longevity. This conclusion directly contradicts some pleiotropic theories of aging that postulate a "cost of reproduction", and it supports theories of aging as an adaptive genetic program. PMID:22817535

  10. Decision-level adaptation in motion perception.

    PubMed

    Mather, George; Sharman, Rebecca J

    2015-12-01

    Prolonged exposure to visual stimuli causes a bias in observers' responses to subsequent stimuli. Such adaptation-induced biases are usually explained in terms of changes in the relative activity of sensory neurons in the visual system which respond selectively to the properties of visual stimuli. However, the bias could also be due to a shift in the observer's criterion for selecting one response rather than the alternative; adaptation at the decision level of processing rather than the sensory level. We investigated whether adaptation to implied motion is best attributed to sensory-level or decision-level bias. Three experiments sought to isolate decision factors by changing the nature of the participants' task while keeping the sensory stimulus unchanged. Results showed that adaptation-induced bias in reported stimulus direction only occurred when the participants' task involved a directional judgement, and disappeared when adaptation was measured using a non-directional task (reporting where motion was present in the display, regardless of its direction). We conclude that adaptation to implied motion is due to decision-level bias, and that a propensity towards such biases may be widespread in sensory decision-making. PMID:27019726

  11. Decision-level adaptation in motion perception

    PubMed Central

    2015-01-01

    Prolonged exposure to visual stimuli causes a bias in observers' responses to subsequent stimuli. Such adaptation-induced biases are usually explained in terms of changes in the relative activity of sensory neurons in the visual system which respond selectively to the properties of visual stimuli. However, the bias could also be due to a shift in the observer's criterion for selecting one response rather than the alternative; adaptation at the decision level of processing rather than the sensory level. We investigated whether adaptation to implied motion is best attributed to sensory-level or decision-level bias. Three experiments sought to isolate decision factors by changing the nature of the participants' task while keeping the sensory stimulus unchanged. Results showed that adaptation-induced bias in reported stimulus direction only occurred when the participants' task involved a directional judgement, and disappeared when adaptation was measured using a non-directional task (reporting where motion was present in the display, regardless of its direction). We conclude that adaptation to implied motion is due to decision-level bias, and that a propensity towards such biases may be widespread in sensory decision-making. PMID:27019726

  12. Bayesian Decision Theory for Multi-Category Adaptive Testing

    NASA Astrophysics Data System (ADS)

    Marinagi, Catherine C.; Kaburlasos, Vassilis G.

    2008-09-01

    This work presents a method for item selection in adaptive tests based on Bayesian Decision Theory (BDT). Multiple categories of examinee's competence level are assumed. The method determines the probability an examinee belongs to each category using Bayesian statistics. Before starting a test, prior probabilities of an examinee are assumed. Then, each time an examinee responds to a single item, a new competence level is estimated "a-posteriori" using item response and prior probabilities values. A customized focus-of-attention vector of probabilities is estimated, which is used to draw the next item from the Item Bank. The latter vector considers both Personalized Cost and content balancing percentages of items.

  13. What nurse leaders should know about complex adaptive systems theory.

    PubMed

    Penprase, Barbara; Norris, Diane

    2005-01-01

    The purpose of this article is to provide an overview of key concepts in understanding complex adaptive systems theory (CAS) and its application to nursing management. CAS concerns altering management practice and revolutionizing how nurse leaders think, behave, and problem solve. CAS discards former beliefs and embraces the concepts of self-organization and attractors (catalysts that allow new behaviors to emerge spontaneously) that enable order and creativity to emerge. Stressing that the most powerful processes begin at the micro level of an organization with the staff, complexity science offers nursing leadership new strategies for successfully navigating chaotic, complex times in health care management. PMID:16206697

  14. Intermolecular interactions in photodamaged DNA from density functional theory symmetry-adapted perturbation theory.

    PubMed

    Sadeghian, Keyarash; Bocola, Marco; Schütz, Martin

    2011-05-01

    The intermolecular interactions of the photodamaged cyclobutane pyrimidine dimer (CPD) lesion with adjacent nucleobases in the native intrahelical DNA double strand are investigated at the level of density functional theory symmetry-adapted perturbation theory (DFT-SAPT) and compared to the original (or repaired) case with pyrimidines (TpT) instead of CPD. The CPD aggregation is on average destabilized by about 6 kcal mol(-1) relative to that involving TpT. The effect of destabilization is asymmetric, that is, it involves a single H-bonding (Watson-Crick (WC) type) base-pair interaction. PMID:21452189

  15. Building a Middle-Range Theory of Adaptive Spirituality.

    PubMed

    Dobratz, Marjorie C

    2016-04-01

    The purpose of this article is to describe a Roy adaptation model based- research abstraction, the findings of which were synthesized into a middle-range theory (MRT) of adaptive spirituality. The published literature yielded 21 empirical studies that investigated religion/spirituality. Quantitative results supported the influence of spirituality on quality of life, psychosocial adjustment, well-being, adaptive coping, and the self-concept mode. Qualitative findings showed the importance of spiritual expressions, values, and beliefs in adapting to chronic illness, bereavement, death, and other life transitions. These findings were abstracted into six theoretical statements, a conceptual definition of adaptive spirituality, and three hypotheses for future testing. PMID:26980894

  16. Analysis of morphological structuring elements generated using adaptive resonance theory

    NASA Astrophysics Data System (ADS)

    Sharpe, John P.; Sungar, Nilgun; Narayanswamy, Ramkumar; Johnson, Kristina M.

    1995-03-01

    In this paper we consider the formation of morphological templates using adaptive resonance theory. We examine the role of object variability and noise on the clustering of different sized objects as a function of the vigilance parameter. We demonstrate that the fuzzy adaptive resonance theory is robust in the presence of noise but that for poor choice of vigilance there is a proliferation of prototypical categories. We apply the technique to detection of abnormal cells in pap smears.

  17. Conceptual development: an adaptive resonance theory model of polysemy

    NASA Astrophysics Data System (ADS)

    Dunbar, George L.

    1997-04-01

    Adaptive Resonance Theory provides a model of pattern classification that addresses the plasticity--stability dilemma and allows a neural network to detect when to construct a new category without the assistance of a supervisor. We show that Adaptive Resonance Theory can be applied to the study of natural concept development. Specifically, a model is presented which is able to categorize different usages of a common noun and group the polysemous senses appropriately.

  18. A Sharing Item Response Theory Model for Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Segall, Daniel O.

    2004-01-01

    A new sharing item response theory (SIRT) model is presented that explicitly models the effects of sharing item content between informants and test takers. This model is used to construct adaptive item selection and scoring rules that provide increased precision and reduced score gains in instances where sharing occurs. The adaptive item selection…

  19. National-level progress on adaptation

    NASA Astrophysics Data System (ADS)

    Lesnikowski, Alexandra; Ford, James; Biesbroek, Robbert; Berrang-Ford, Lea; Heymann, S. Jody

    2016-03-01

    It is increasingly evident that adaptation will figure prominently in the post-2015 United Nations climate change agreement. As adaptation obligations under the United Nations Framework Convention on Climate Change evolve, more rigorous approaches to measuring adaptation progress among parties will be critical. In this Letter we elaborate on an emerging area of research referred to as `adaptation tracking’, which has potential to inform development of a global adaptation monitoring framework. We evaluate this potential by presenting evidence on policy change for 41 high-income countries between 2010 and 2014. We examine whether countries that were in early stages of adaptation planning in 2010 are making progress to close adaptation gaps, and how the landscape of adaptation in these countries has evolved. In total we find an 87% increase in reported adaptation policies and measures, and evidence that implementation of concrete adaptation initiatives is growing. Reflecting on the strengths and challenges of this early methodology, we further discuss how adaptation tracking practices could guide development of a robust framework for monitoring global adaptation progress and inform future research on policy change across countries.

  20. "Theory of food" as a neurocognitive adaptation.

    PubMed

    Allen, John S

    2012-01-01

    Human adult cognition emerges over the course of development via the interaction of multiple critical neurocognitive networks. These networks evolved in response to various selection pressures, many of which were modified or intensified by the intellectual, technological, and sociocultural environments that arose in connection with the evolution of genus Homo. Networks related to language and theory of mind clearly play an important role in adult cognition. Given the critical importance of food to both basic survival and cultural interaction, a "theory of food" (analogous to theory of mind) may represent another complex network essential for normal cognition. I propose that theory of food evolved as an internal, cognitive representation of our diets in our minds. Like other complex cognitive abilities, it relies on complex and overlapping dedicated neural networks that develop in childhood under familial and cultural influences. Normative diets are analogous to first languages in that they are acquired without overt teaching; they are also difficult to change or modify once a critical period in development is passed. Theory of food suggests that cognitive activities related to food may be cognitive enhancers, which could have implications for maintaining healthy brain function in aging. PMID:22262561

  1. Emergent “quantum” theory in complex adaptive systems

    NASA Astrophysics Data System (ADS)

    Minic, Djordje; Pajevic, Sinisa

    2016-03-01

    Motivated by the question of stability, in this paper we argue that an effective quantum-like theory can emerge in complex adaptive systems. In the concrete example of stochastic Lotka-Volterra dynamics, the relevant effective “Planck constant” associated with such emergent “quantum” theory has the dimensions of the square of the unit of time. Such an emergent quantum-like theory has inherently nonclassical stability as well as coherent properties that are not, in principle, endangered by thermal fluctuations and therefore might be of crucial importance in complex adaptive systems.

  2. Nonlinear adaptive networks: A little theory, a few applications

    SciTech Connect

    Jones, R.D.; Qian, S.; Barnes, C.W.; Bisset, K.R.; Bruce, G.M.; Lee, K.; Lee, L.A.; Mead, W.C.; O'Rourke, M.K.; Thode, L.E. ); Lee, Y.C.; Flake, G.W. Maryland Univ., College Park, MD ); Poli, I.J. Bologna Univ. )

    1990-01-01

    We present the theory of nonlinear adaptive networks and discuss a few applications. In particular, we review the theory of feedforward backpropagation networks. We than present the theory of the Connectionist Normalized Linear Spline network in both its feedforward and iterated modes. Also, we briefly discuss the theory of stochastic cellular automata. We then discuss applications to chaotic time series tidal prediction in Venice Lagoon, sonar transient detection, control of nonlinear processes, balancing a double inverted pendulum and design advice for free electron lasers. 26 refs., 23 figs.

  3. Cognitive Adaptation Theory and Breast Cancer Recurrence: Are There Limits?

    ERIC Educational Resources Information Center

    Tomich, Patricia L.; Helgeson, Vicki S.

    2006-01-01

    Relations of the components of cognitive adaptation theory (self-esteem, optimism, control) to quality of life and benefit finding were examined for 70 women (91% Caucasian) diagnosed with Stage I, II, or III breast cancer over 5 years ago. Half of these women experienced a recurrence within the 5 years; the other half remained disease free. Women…

  4. Multi-level coupled cluster theory

    SciTech Connect

    Myhre, Rolf H.; Koch, Henrik; Sánchez de Merás, Alfredo M. J.

    2014-12-14

    We present a general formalism where different levels of coupled cluster theory can be applied to different parts of the molecular system. The system is partitioned into subsystems by Cholesky decomposition of the one-electron Hartree-Fock density matrix. In this way the system can be divided across chemical bonds without discontinuities arising. The coupled cluster wave function is defined in terms of cluster operators for each part and these are determined from a set of coupled equations. The total wave function fulfills the Pauli-principle across all borders and levels of electron correlation. We develop the associated response theory for this multi-level coupled cluster theory and present proof of principle applications. The formalism is an essential tool in order to obtain size-intensive complexity in the calculation of local molecular properties.

  5. Eco-evolutionary feedbacks, adaptive dynamics and evolutionary rescue theory

    PubMed Central

    Ferriere, Regis; Legendre, Stéphane

    2013-01-01

    Adaptive dynamics theory has been devised to account for feedbacks between ecological and evolutionary processes. Doing so opens new dimensions to and raises new challenges about evolutionary rescue. Adaptive dynamics theory predicts that successive trait substitutions driven by eco-evolutionary feedbacks can gradually erode population size or growth rate, thus potentially raising the extinction risk. Even a single trait substitution can suffice to degrade population viability drastically at once and cause ‘evolutionary suicide’. In a changing environment, a population may track a viable evolutionary attractor that leads to evolutionary suicide, a phenomenon called ‘evolutionary trapping’. Evolutionary trapping and suicide are commonly observed in adaptive dynamics models in which the smooth variation of traits causes catastrophic changes in ecological state. In the face of trapping and suicide, evolutionary rescue requires that the population overcome evolutionary threats generated by the adaptive process itself. Evolutionary repellors play an important role in determining how variation in environmental conditions correlates with the occurrence of evolutionary trapping and suicide, and what evolutionary pathways rescue may follow. In contrast with standard predictions of evolutionary rescue theory, low genetic variation may attenuate the threat of evolutionary suicide and small population sizes may facilitate escape from evolutionary traps. PMID:23209163

  6. Internal Models in Sensorimotor Integration: Perspectives from Adaptive Control Theory

    PubMed Central

    Tin, Chung; Poon, Chi-Sang

    2007-01-01

    Internal model and adaptive control are empirical and mathematical paradigms that have evolved separately to describe learning control processes in brain systems and engineering systems, respectively. This paper presents a comprehensive appraisal of the correlation between these paradigms with a view to forging a unified theoretical framework that may benefit both disciplines. It is suggested that the classic equilibrium-point theory of impedance control of arm movement is analogous to continuous gain-scheduling or high-gain adaptive control within or across movement trials, respectively, and that the recently proposed inverse internal model is akin to adaptive sliding control originally for robotic manipulator applications. Modular internal models architecture for multiple motor tasks is a form of multi-model adaptive control. Stochastic methods such as generalized predictive control, reinforcement learning, Bayesian learning and Hebbian feedback covariance learning are reviewed and their possible relevance to motor control is discussed. Possible applicability of Luenberger observer and extended Kalman filter to state estimation problems such as sensorimotor prediction or the resolution of vestibular sensory ambiguity is also discussed. The important role played by vestibular system identification in postural control suggests an indirect adaptive control scheme whereby system states or parameters are explicitly estimated prior to the implementation of control. This interdisciplinary framework should facilitate the experimental elucidation of the mechanisms of internal model in sensorimotor systems and the reverse engineering of such neural mechanisms into novel brain-inspired adaptive control paradigms in future. PMID:16135881

  7. Scale-adaptive tensor algebra for local many-body methods of electronic structure theory

    SciTech Connect

    Liakh, Dmitry I

    2014-01-01

    While the formalism of multiresolution analysis (MRA), based on wavelets and adaptive integral representations of operators, is actively progressing in electronic structure theory (mostly on the independent-particle level and, recently, second-order perturbation theory), the concepts of multiresolution and adaptivity can also be utilized within the traditional formulation of correlated (many-particle) theory which is based on second quantization and the corresponding (generally nonorthogonal) tensor algebra. In this paper, we present a formalism called scale-adaptive tensor algebra (SATA) which exploits an adaptive representation of tensors of many-body operators via the local adjustment of the basis set quality. Given a series of locally supported fragment bases of a progressively lower quality, we formulate the explicit rules for tensor algebra operations dealing with adaptively resolved tensor operands. The formalism suggested is expected to enhance the applicability and reliability of local correlated many-body methods of electronic structure theory, especially those directly based on atomic orbitals (or any other localized basis functions).

  8. A synthesis theory for self-oscillating adaptive systems /SOAS/

    NASA Technical Reports Server (NTRS)

    Horowitz, I.; Smay, J.; Shapiro, A.

    1974-01-01

    A quantitative synthesis theory is presented for the Self-Oscillating Adaptive System (SOAS), whose nonlinear element has a static, odd character with hard saturation. The synthesis theory is based upon the quasilinear properties of the SOAS to forced inputs, which permits the extension of quantitative linear feedback theory to the SOAS. A reasonable definition of optimum design is shown to be the minimization of the limit cycle frequency. The great advantages of the SOAS is its zero sensitivity to pure gain changes. However, quasilinearity and control of the limit cycle amplitude at the system output, impose additional constraints which partially or completely cancel this advantage, depending on the numerical values of the design parameters. By means of narrow-band filtering, an additional factor is introduced which permits trade-off between filter complexity and limit cycle frequency minimization.

  9. Information theory of adaptation in neurons, behavior, and mood

    PubMed Central

    Sharpee, Tatyana O.; Calhoun, Adam J.; Chalasani, Sreekanth H.

    2014-01-01

    The ability to make accurate predictions of future stimuli and consequences of one’s actions are crucial for the survival and appropriate decision-making. These predictions are constantly being made at different levels of the nervous system. This is evidenced by adaptation to stimulus parameters in sensory coding, and in learning of an up-to-date model of the environment at the behavioral level. This review will discuss recent findings that actions of neurons and animals are selected based on detailed stimulus history in such a way as to maximize information for achieving the task at hand. Information maximization dictates not only how sensory coding should adapt to various statistical aspects of stimuli, but also that reward function should adapt to match the predictive information from past to future. PMID:24709600

  10. Current conserving theory at the operator level

    NASA Astrophysics Data System (ADS)

    Yuan, Jiangtao; Wang, Yin; Wang, Jian

    The basic assumption of quantum transport in mesoscopic systems is that the total charge inside the scattering region is zero. This means that the potential deep inside reservoirs is effectively screened and therefore the electric field at interface of scattering region is zero. Thus the current conservation condition can be satisfied automatically which is an important condition in mesoscopic transport. So far the current conserving ac theory is well developed by considering the displacement current which is due to Coulomb interaction if we just focus on the average current. However, the frequency dependent shot noise does not satisfy the conservation condition since we do not consider the current conservation at the operator level. In this work, we formulate a generalized current conserving theory at the operator level using non-equilibrium Green's function theory which could be applied to both average current and frequency dependent shot noise. A displacement operator is derived for the first time so that the frequency dependent correlation of displacement currents could be investigated. Moreover, the equilibrium shot noise is investigated and a generalized fluctuation-dissipation relationship is presented.

  11. Adaptation, high-level vision, and the phenomenology of perception

    NASA Astrophysics Data System (ADS)

    Webster, Michael A.

    2002-06-01

    To what extent do we have shared or unique visual experiences? This paper examines how the answer to this question is constrained by known processes of visual adaptation. Adaptation constantly recalibrates visual sensitivity so that our vision is matched to the stimuli that we are currently exposed to. These processes normalize perception not only to low-level features in the image, but to high-level, biologically relevant properties of the visual world. They can therefore strongly impact many natural perceptual judgments. To the extent that observers are exposed to and thus adapted by a different environment, their vision will be normalized in different ways and their subjective visual experience will differ. These differences are illustrated by considering how adaptation can influence human face perception. To the extent that observers are exposed and adapted to common properties in the environment, their vision will be adjusted toward common states, and in this respect they will have a common visual experience. This is illustrated by reviewing the effects of adaptation on the perception of image blur. In either case, it is the similarities or differences in the stimuli - and not the intrinsic similarities or differences in the observers - which determine the relative states of adaptation. Thus at least some aspects of our private internal experience are controlled by external factors that are accessible to objective measurement.

  12. Adaptive dynamic programming as a theory of sensorimotor control.

    PubMed

    Jiang, Yu; Jiang, Zhong-Ping

    2014-08-01

    Many characteristics of sensorimotor control can be explained by models based on optimization and optimal control theories. However, most of the previous models assume that the central nervous system has access to the precise knowledge of the sensorimotor system and its interacting environment. This viewpoint is difficult to be justified theoretically and has not been convincingly validated by experiments. To address this problem, this paper presents a new computational mechanism for sensorimotor control from a perspective of adaptive dynamic programming (ADP), which shares some features of reinforcement learning. The ADP-based model for sensorimotor control suggests that a command signal for the human movement is derived directly from the real-time sensory data, without the need to identify the system dynamics. An iterative learning scheme based on the proposed ADP theory is developed, along with rigorous convergence analysis. Interestingly, the computational model as advocated here is able to reproduce the motor learning behavior observed in experiments where a divergent force field or velocity-dependent force field was present. In addition, this modeling strategy provides a clear way to perform stability analysis of the overall system. Hence, we conjecture that human sensorimotor systems use an ADP-type mechanism to control movements and to achieve successful adaptation to uncertainties present in the environment. PMID:24962078

  13. Molecular-level tradeoffs and metabolic adaptation to simultaneous stressors

    PubMed Central

    Carlson, Ross P.; Taffs, Reed L.

    2010-01-01

    Summary Life is a dynamic process driven by the complex interplay between physical constraints and selection pressures, ranging from nutrient limitation to inhibitory substances to predators. These stressors are not mutually exclusive; microbes have faced concurrent challenges for eons. Genome-enabled systems biology approaches are adapting economic and ecological concepts like tradeoff curves and strategic resource allocation theory to analyze metabolic adaptations to simultaneous stressors. These methodologies can accurately describe and predict metabolic adaptations to concurrent stresses by considering the tradeoff between investment of limiting resources into enzymatic machinery and the resulting cellular function. The approaches represent promising links between computational biology and well established economic and ecological methodologies for analyzing the interplay between physical constraints and microbial fitness. PMID:20637598

  14. Lessons from Adaptive Level One Accelerator (ALOA) System Implementation

    NASA Technical Reports Server (NTRS)

    Patel, Umesh D.; Brambora, Clifford; Ghuman, Parminder; Day, John H. (Technical Monitor)

    2001-01-01

    The Adaptive Level One Accelerator (ALOA) system was developed as part of the Earth Science Data and Information System (ESDIS) project. The reconfigurable computing technologies were investigated for Level 1 satellite telemetry data processing to achieve computing acceleration and cost reduction for the next-generation Level 1 data processing systems. The MODIS instrument calibration algorithm was implemented using reconfigurable a computer. The system development process and the lessons learned throughout the design cycle are summarized in this paper.

  15. Rapid perceptual adaptation to high gravitoinertial force levels Evidence for context-specific adaptation

    NASA Technical Reports Server (NTRS)

    Lackner, J. R.; Graybiel, A.

    1982-01-01

    Subjects exposed to periodic variations in gravitoinertial force (2-G peak) in parabolic flight maneuvers quickly come to perceive the peak force level as having decreased in intensity. By the end of a 40-parabola flight, the decrease in apparent force is approximately 40%. On successive flight days, the apparent intensity of the force loads seems to decrease as well, indicating a cumulative adaptive effect. None of the subjects reported feeling abnormally 'light' for more than a minute or two after return to 1-G background force levels. The pattern of findings suggests a context-specific adaptation to high-force levels.

  16. Complex adaptive systems and game theory: An unlikely union

    USGS Publications Warehouse

    Hadzikadic, M.; Carmichael, T.; Curtin, C.

    2010-01-01

    A Complex Adaptive System is a collection of autonomous, heterogeneous agents, whose behavior is defined with a limited number of rules. A Game Theory is a mathematical construct that assumes a small number of rational players who have a limited number of actions or strategies available to them. The CAS method has the potential to alleviate some of the shortcomings of GT. On the other hand, CAS researchers are always looking for a realistic way to define interactions among agents. GT offers an attractive option for defining the rules of such interactions in a way that is both potentially consistent with observed real-world behavior and subject to mathematical interpretation. This article reports on the results of an effort to build a CAS system that utilizes GT for determining the actions of individual agents. ?? 2009 Wiley Periodicals, Inc. Complexity, 16,24-42, 2010.

  17. A synthesis theory for the externally excited adaptive system /EEAS/

    NASA Technical Reports Server (NTRS)

    Horowitz, I. M.; Smay, J. W.; Shapiro, A.

    1974-01-01

    The externally excited adaptive system (EEAS) is a two-degree-of-freedom feedback system with a nonlinearity which is saturated hard by an external periodic signal. Under certain conditions, the EEAS responds quasi-linearly to command and plant disturbance signals, permitting the development of a quantitative synthesis theory for satisfying system tolerances despite large plant uncertainty. The great advantage of the EEAS is its zero sensitivity to plant gain variations, a property it shares with the self-oscillating adaptive system (SOAS). The EEAS is, however, more flexible than the SOAS in satisfying the quasi-linearity constraints. The essential difference is that in the EEAS the loop transmission bandwidth is not rigorously tied to the 'carrier' signal, as it is in the SOAS. There is a class of problems for which the EEAS is superior to the purely linear system, which in turn is superior to the SOAS. The superiority of the EEAS over the SOAS is especially marked in the case of significant plant disturbances, which generally vitiate a SOAS design.

  18. Adaptive control with an expert system based supervisory level. Thesis

    NASA Technical Reports Server (NTRS)

    Sullivan, Gerald A.

    1991-01-01

    Adaptive control is presently one of the methods available which may be used to control plants with poorly modelled dynamics or time varying dynamics. Although many variations of adaptive controllers exist, a common characteristic of all adaptive control schemes, is that input/output measurements from the plant are used to adjust a control law in an on-line fashion. Ideally the adjustment mechanism of the adaptive controller is able to learn enough about the dynamics of the plant from input/output measurements to effectively control the plant. In practice, problems such as measurement noise, controller saturation, and incorrect model order, to name a few, may prevent proper adjustment of the controller and poor performance or instability result. In this work we set out to avoid the inadequacies of procedurally implemented safety nets, by introducing a two level control scheme in which an expert system based 'supervisor' at the upper level provides all the safety net functions for an adaptive controller at the lower level. The expert system is based on a shell called IPEX, (Interactive Process EXpert), that we developed specifically for the diagnosis and treatment of dynamic systems. Some of the more important functions that the IPEX system provides are: (1) temporal reasoning; (2) planning of diagnostic activities; and (3) interactive diagnosis. Also, because knowledge and control logic are separate, the incorporation of new diagnostic and treatment knowledge is relatively simple. We note that the flexibility available in the system to express diagnostic and treatment knowledge, allows much greater functionality than could ever be reasonably expected from procedural implementations of safety nets. The remainder of this chapter is divided into three sections. In section 1.1 we give a detailed review of the literature in the area of supervisory systems for adaptive controllers. In particular, we describe the evolution of safety nets from simple ad hoc techniques, up

  19. Development and Standardization of the Diagnostic Adaptive Behavior Scale: Application of Item Response Theory to the Assessment of Adaptive Behavior

    ERIC Educational Resources Information Center

    Tassé, Marc J.; Schalock, Robert L.; Thissen, David; Balboni, Giulia; Bersani, Henry, Jr.; Borthwick-Duffy, Sharon A.; Spreat, Scott; Widaman, Keith F.; Zhang, Dalun; Navas, Patricia

    2016-01-01

    The Diagnostic Adaptive Behavior Scale (DABS) was developed using item response theory (IRT) methods and was constructed to provide the most precise and valid adaptive behavior information at or near the cutoff point of making a decision regarding a diagnosis of intellectual disability. The DABS initial item pool consisted of 260 items. Using IRT…

  20. Competitive Two-Level Adaptive Scheduling Using Resource Augmentation

    NASA Astrophysics Data System (ADS)

    Sun, Hongyang; Cao, Yangjie; Hsu, Wen-Jing

    As multi-core processors proliferate, it has become more important than ever to ensure efficient execution of parallel jobs on multiprocessor systems. In this paper, we study the problem of scheduling parallel jobs with arbitrary release time on multiprocessors while minimizing the jobs’ mean response time. We focus on non-clairvoyant scheduling schemes that adaptively reallocate processors based on periodic feedbacks from the individual jobs. Since it is known that no deterministic non-clairvoyant algorithm is competitive for this problem, we focus on resource augmentation analysis, and show that two adaptive algorithms, Agdeq and Abgdeq, achieve competitive performance using O(1) times faster processors than the adversary. These results are obtained through a general framework for analyzing the mean response time of any two-level adaptive scheduler. Our simulation results verify the effectiveness of Agdeq and Abgdeq by evaluating their performances over a wide range of workloads consisting of synthetic parallel jobs with different parallelism characteristics.

  1. Iterative Robust Capon Beamforming with Adaptively Updated Array Steering Vector Mismatch Levels

    PubMed Central

    Sun, Liguo

    2014-01-01

    The performance of the conventional adaptive beamformer is sensitive to the array steering vector (ASV) mismatch. And the output signal-to interference and noise ratio (SINR) suffers deterioration, especially in the presence of large direction of arrival (DOA) error. To improve the robustness of traditional approach, we propose a new approach to iteratively search the ASV of the desired signal based on the robust capon beamformer (RCB) with adaptively updated uncertainty levels, which are derived in the form of quadratically constrained quadratic programming (QCQP) problem based on the subspace projection theory. The estimated levels in this iterative beamformer present the trend of decreasing. Additionally, other array imperfections also degrade the performance of beamformer in practice. To cover several kinds of mismatches together, the adaptive flat ellipsoid models are introduced in our method as tight as possible. In the simulations, our beamformer is compared with other methods and its excellent performance is demonstrated via the numerical examples. PMID:27355008

  2. 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

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

    PubMed

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

    2014-12-01

    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

  4. Prospect theory or construal level theory? Diminishing sensitivity vs. psychological distance in risky decisions.

    PubMed

    Trautmann, Stefan T; van de Kuilen, Gijs

    2012-01-01

    Attitudes toward risks are central to organizational decisions. These attitudes are commonly modeled by prospect theory. Construal level theory has been proposed as an alternative theory of risky choice, accounting for psychological distance deriving from temporal, spatial and social aspects of risk that are typical of agency situations. Unnoticed in the literature, the two theories make contradicting predictions. The current study investigates which theory provides a better description of risky decisions in the presence of temporal, spatial, and social factors. We find that the psychophysical effects modeled by prospect theory dominate the psychological distance effects of construal level theory. PMID:22011526

  5. Tuned range-separated hybrid functionals in the symmetry-adapted perturbation theory

    SciTech Connect

    Hapka, Michał; Modrzejewski, Marcin; Rajchel, Łukasz; Chałasiński, Grzegorz; Szczęśniak, Małgorzata M.

    2014-10-07

    The aim of this study is to present a performance test of optimally tuned long-range corrected (LRC) functionals applied to the symmetry-adapted perturbation theory (SAPT). In the present variant, the second-order energy components are evaluated at the coupled level of theory. We demonstrate that the generalized Kohn-Sham (GKS) description of monomers with optimally tuned LRC functionals may be essential for the quality of SAPT interaction energy components. This is connected to the minimization of a many-electron self-interaction error and exemplified by two model systems: polyacetylenes of increasing length and stretching of He{sub 3}{sup +}. Next we provide a comparison of SAPT approaches based on Kohn-Sham and GKS description of the monomers. We show that LRC leads to results better or comparable with the hitherto prevailing asymptotically corrected functionals. Finally, we discuss the advantages and possible limitations of SAPT based on LRC functionals.

  6. 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

  7. 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.…

  8. A Theory of Complex Adaptive Inquiring Organizations: Application to Continuous Assurance of Corporate Financial Information

    ERIC Educational Resources Information Center

    Kuhn, John R., Jr.

    2009-01-01

    Drawing upon the theories of complexity and complex adaptive systems and the Singerian Inquiring System from C. West Churchman's seminal work "The Design of Inquiring Systems" the dissertation herein develops a systems design theory for continuous auditing systems. The dissertation consists of discussion of the two foundational theories,…

  9. Adapting to Rising Sea Level: A Florida Perspective

    NASA Astrophysics Data System (ADS)

    Parkinson, Randall W.

    2009-07-01

    Global climate change and concomitant rising sea level will have a profound impact on Florida's coastal and marine systems. Sea-level rise will increase erosion of beaches, cause saltwater intrusion into water supplies, inundate coastal marshes and other important habitats, and make coastal property more vulnerable to erosion and flooding. Yet most coastal areas are currently managed under the premise that sea-level rise is not significant and the shorelines are static or can be fixed in place by engineering structures. The new reality of sea-level rise and extreme weather due to climate change requires a new style of planning and management to protect resources and reduce risk to humans. Scientists must: (1) assess existing coastal vulnerability to address short term management issues and (2) model future landscape change and develop sustainable plans to address long term planning and management issues. Furthermore, this information must be effectively transferred to planners, managers, and elected officials to ensure their decisions are based upon the best available information. While there is still some uncertainty regarding the details of rising sea level and climate change, development decisions are being made today which commit public and private investment in real estate and associated infrastructure. With a design life of 30 yrs to 75 yrs or more, many of these investments are on a collision course with rising sea level and the resulting impacts will be significant. In the near term, the utilization of engineering structures may be required, but these are not sustainable and must ultimately yield to "managed withdrawal" programs if higher sea-level elevations or rates of rise are forthcoming. As an initial step towards successful adaptation, coastal management and planning documents (i.e., comprehensive plans) must be revised to include reference to climate change and rising sea-level.

  10. Construal-Level Theory of Psychological Distance

    PubMed Central

    Trope, Yaacov; Liberman, Nira

    2011-01-01

    People are capable of thinking about the future, the past, remote locations, another person’s perspective, and counterfactual alternatives. Without denying the uniqueness of each process, it is proposed that they constitute different forms of traversing psychological distance. Psychological distance is egocentric: Its reference point is the self in the here and now, and the different ways in which an object might be removed from that point—in time, in space, in social distance, and in hypotheticality—constitute different distance dimensions. Transcending the self in the here and now entails mental construal, and the farther removed an object is from direct experience, the higher (more abstract) the level of construal of that object. Supporting this analysis, research shows (a) that the various distances are cognitively related to each other, (b) that they similarly influence and are influenced by level of mental construal, and (c) that they similarly affect prediction, preference, and action. PMID:20438233

  11. Climate change adaptation under uncertainty in the developing world: A case study of sea level rise in Kiribati

    NASA Astrophysics Data System (ADS)

    Donner, S. D.; Webber, S.

    2011-12-01

    Climate change is expected to have the greatest impact in parts of the developing world. At the 2010 meeting of U.N. Framework Convention on Climate Change in Cancun, industrialized countries agreed in principle to provide US$100 billion per year by 2020 to assist the developing world respond to climate change. This "Green Climate Fund" is a critical step towards addressing the challenge of climate change. However, the policy and discourse on supporting adaptation in the developing world remains highly idealized. For example, the efficacy of "no regrets" adaptation efforts or "mainstreaming" adaptation into decision-making are rarely evaluated in the real world. In this presentation, I will discuss the gap between adaptation theory and practice using a multi-year case study of the cultural, social and scientific obstacles to adapting to sea level rise in the Pacific atoll nation of Kiribati. Our field research reveals how scientific and institutional uncertainty can limit international efforts to fund adaptation and lead to spiraling costs. Scientific uncertainty about hyper-local impacts of sea level rise, though irreducible, can at times limit decision-making about adaptation measures, contrary to the notion that "good" decision-making practices can incorporate scientific uncertainty. Efforts to improve institutional capacity must be done carefully, or they risk inadvertently slowing the implementation of adaptation measures and increasing the likelihood of "mal"-adaptation.

  12. A Theory of Secondary Teachers' Adaptations When Implementing a Reading Intervention Program

    ERIC Educational Resources Information Center

    Leko, Melinda M.; Roberts, Carly A.; Pek, Yvonne

    2015-01-01

    This study examined the causes and consequences of secondary teachers' adaptations when implementing a research-based reading intervention program. Interview, observation, and artifact data were collected on five middle school intervention teachers, leading to a grounded theory composed of the core component, reconciliation through adaptation, and…

  13. Multi-Attribute Utility Theory and Adaptive Techniques for Intelligent Web-Based Educational Software

    ERIC Educational Resources Information Center

    Kabassi, K.; Virvou, M.

    2006-01-01

    This paper describes how the Multi-Attribute Utility Theory can be combined with adaptive techniques to improve individualised teaching in an Intelligent Learning Environment (ILE). The ILE is called Web F-SMILE, it operates over the Web and is meant to help novice users learn basic skills of computer use. Tutoring is dynamically adapted to the…

  14. Block-structured adaptive mesh refinement - theory, implementation and application

    SciTech Connect

    Deiterding, Ralf

    2011-01-01

    Structured adaptive mesh refinement (SAMR) techniques can enable cutting-edge simulations of problems governed by conservation laws. Focusing on the strictly hyperbolic case, these notes explain all algorithmic and mathematical details of a technically relevant implementation tailored for distributed memory computers. An overview of the background of commonly used finite volume discretizations for gas dynamics is included and typical benchmarks to quantify accuracy and performance of the dynamically adaptive code are discussed. Large-scale simulations of shock-induced realistic combustion in non-Cartesian geometry and shock-driven fluid-structure interaction with fully coupled dynamic boundary motion demonstrate the applicability of the discussed techniques for complex scenarios.

  15. A Grounded Theory of Master's-Level Counselor Research Identity

    ERIC Educational Resources Information Center

    Jorgensen, Maribeth F.; Duncan, Kelly

    2015-01-01

    A grounded theory approach was used to examine the research identity of 17 master's-level counseling trainees and practitioners. The emergent theory gave an understanding to sources of variation in the process and outcome of research identity. The authors provide recommendations for counselor educators to use with current and former students.

  16. Psychological Adaptation to Disability: Perspectives From Chaos and Complexity Theory

    ERIC Educational Resources Information Center

    Livneh, Hanoch; Parker, Randall M.

    2005-01-01

    The process of psychological adaptation to chronic illness and disability (CID) has been extensively studied by rehabilitation professionals for more than 50 years, yet it is still fraught with misunderstanding and often contradictory views. In this paper, the authors seek to expand on earlier suggestions by Parker, Schaller, and Hansmann (2003)…

  17. Item Response Theory and Computerized Adaptive Testing Conference Proceedings (Wayzata, Minnesota, July 27-30, 1982).

    ERIC Educational Resources Information Center

    Weiss, David J., Ed.

    This report contains the Proceedings of the 1982 Item Response Theory and Computerized Adaptive Testing Conference. The papers and their discussions are organized into eight sessions: (1) "Developments in Latent Trait Theory," with papers by Fumiko Samejima and Michael V. Levine; (2) "Parameter Estimation," with papers by Frederic M. Lord and…

  18. An Adaptation of Dual Labor Market Theory to the Evaluation of an Youth Employment Project.

    ERIC Educational Resources Information Center

    Spiessl, Ronald W.

    This paper reports the problems arising out of, and the solution developed, in adapting dual labor market theory to the evaluation of a CETA youth employment demonstration project. The theory posits that some jobs operate within a primary labor market, and are characterized by good wages and benefits, job security and potential for within firm…

  19. Brief Report: Translation and Adaptation of the Theory of Mind Inventory to Spanish

    ERIC Educational Resources Information Center

    Pujals, Elena; Batlle, Santiago; Camprodon, Ester; Pujals, Sílvia; Estrada, Xavier; Aceña, Marta; Petrizan, Araitz; Duñó, Lurdes; Martí, Josep; Martin, Luis Miguel; Pérez-Solá, Víctor

    2016-01-01

    The Theory of Mind Inventory is an informant measure designed to evaluate children's theory of mind competence. We describe the translation and cultural adaptation of the inventory by the following process: (1) translation from English to Spanish by two independent certified translators; (2) production of an agreed version by a multidisciplinary…

  20. 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. PMID:25044043

  1. Theory of Food” as a Neurocognitive Adaptation

    PubMed Central

    Allen, John S.

    2011-01-01

    Human adult cognition emerges over the course of development via the interaction of multiple critical neurocognitive networks. These networks evolved in response to various selection pressures, many of which were modified or intensified by the intellectual, technological, and socio-cultural environments that arose in connection with the evolution of genus Homo. Networks related to language and theory of mind clearly play an important role in adult cognition. Given the critical importance of food to both basic survival and cultural interaction, a “theory of food” (analogous to theory of mind) may represent another complex network essential for normal cognition. I propose that theory of food evolved as an internal, cognitive representation of our diets in our minds. Like other complex cognitive abilities, it relies on complex and overlapping dedicated neural networks that develop in childhood under familial and cultural influences. Normative diets are analogous to first languages in that they are acquired without overt teaching; they are also difficult to change or modify once a critical period in development is passed. Theory of food suggests that cognitive activities related to food may be cognitive enhancers, which could have implications for maintaining healthy brain function in aging. PMID:22262561

  2. Level-by-level artificial viscosity and visualization for MHD simulation with adaptive mesh refinement

    NASA Astrophysics Data System (ADS)

    Hatori, Tomoharu; Ito, Atsushi M.; Nunami, Masanori; Usui, Hideyuki; Miura, Hideaki

    2016-08-01

    We propose a numerical method to determine the artificial viscosity in magnetohydrodynamics (MHD) simulations with adaptive mesh refinement (AMR) method, where the artificial viscosity is adaptively changed due to the resolution level of the AMR hierarchy. Although the suitable value of the artificial viscosity depends on the governing equations and the model of target problem, it can be determined by von Neumann stability analysis. By means of the new method, "level-by-level artificial viscosity method," MHD simulations of Rayleigh-Taylor instability (RTI) are carried out with the AMR method. The validity of the level-by-level artificial viscosity method is confirmed by the comparison of the linear growth rates of RTI between the AMR simulations and the simple simulations with uniform grid and uniform artificial viscosity whose resolution is the same as that in the highest level of the AMR simulation. Moreover, in the nonlinear phase of RTI, the secondary instability is clearly observed where the hierarchical data structure of AMR calculation is visualized as high resolution region floats up like terraced fields. In the applications of the method to general fluid simulations, the growth of small structures can be sufficiently reproduced, while the divergence of numerical solutions can be suppressed.

  3. 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.

  4. Adaptive independent joint control of manipulators - Theory and experiment

    NASA Technical Reports Server (NTRS)

    Seraji, H.

    1988-01-01

    The author presents a simple decentralized adaptive control scheme for multijoint robot manipulators based on the independent joint control concept. The proposed control scheme for each joint consists of a PID (proportional integral and differential) feedback controller and a position-velocity-acceleration feedforward controller, both with adjustable gains. The static and dynamic couplings that exist between the joint motions are compensated by the adaptive independent joint controllers while ensuring trajectory tracking. The proposed scheme is implemented on a MicroVAX II computer for motion control of the first three joints of a PUMA 560 arm. Experimental results are presented to demonstrate that trajectory tracking is achieved despite strongly coupled, highly nonlinear joint dynamics. The results confirm that the proposed decentralized adaptive control of manipulators is feasible, in spite of strong interactions between joint motions. The control scheme presented is computationally very fast and is amenable to parallel processing implementation within a distributed computing architecture, where each joint is controlled independently by a simple algorithm on a dedicated microprocessor.

  5. Symmetry-adapted perturbation theory interaction energy decomposition for some noble gas complexes

    NASA Astrophysics Data System (ADS)

    Cukras, Janusz; Sadlej, Joanna

    2008-06-01

    This Letter contains a study of the interaction energy in HArF⋯N 2 and HArF⋯P 2 complexes. Symmetry-adapted perturbation theory (SAPT) has been applied to analyze the electrostatic, induction, dispersion and exchange contributions to the total interaction energy. The interaction energy has also been obtained by supermolecular method at the MP2, MP4, CCSD, CCSD(T) levels. The interaction energy for the studied complexes results from a partial cancelation of large attractive electrostatic, induction, dispersion terms by a strong repulsive exchange contribution. The induction and dispersion effects proved to be crucial in establishing the preference for the colinear HArF⋯N 2 and HArF⋯P 2 structures and shift direction of νHAr stretching vibrations.

  6. Adapting Structuration Theory as a Comprehensive Theory for Distance Education: The ASTIDE Model

    ERIC Educational Resources Information Center

    Aktaruzzaman, Md; Plunkett, Margaret

    2016-01-01

    Distance Education (DE) theorists have argued about the requirement for a theory to be comprehensive in a way that can explicate many of the activities associated with DE. Currently, Transactional Distance Theory (TDT) (Moore, 1993) and the Theory of Instructional Dialogue (IDT) (Caspi & Gorsky, 2006) are the most prominent theories, yet they…

  7. Brain: a complex adaptive structure at multiple levels

    NASA Astrophysics Data System (ADS)

    Klein, Bradley G.

    2001-10-01

    The human brain is comprised of over 100 billion neurons organized into tracts, nuclei, circuits and systems. This provides innumerable elegant abilities that rely on the nervous system to act as a complex adaptive structure (CAS). This property is apparent with respect to overall function, the function of individual neurons and the function of sensory and motor systems. At the overall functional level, the nervous system monitors the environments and can alter that environment. Alterations such as turning on a light switch or changing the diameter of neural vasculature, can improve the performance or chance for survival of the nervous system. Individual neurons can alter the activity of their electrogenic pumps, their rate of transmitter synthesis, their neurotransmitter release and their receptor density in order to maintain optimal functioning in a circuit following changes in their micro-environment. At the systems level, the visual system adjusts the orientation of the eyes or pupillary diameter to receive the highest quality visual information. In the motor system, the myotatic reflex maintains muscle position in the face of changing load, and the gain of the muscle organ responsible for the myotatic reflex can also be automatically adjusted. Internal homeostasis, essential for optimal performance of the nervous system, can be achieved through complex behavioral actions such as feeding. The hypothalamus plays an important role in such behaviors and in the type of sensorimotor integration responsible for the CAS nature of overall nervous system function. Thinking about the CAS characteristics of the nervous system may lead to development of non-biological CAS prostheses for the brain.

  8. A quantitative evolutionary theory of adaptive behavior dynamics.

    PubMed

    McDowell, J J

    2013-10-01

    The idea that behavior is selected by its consequences in a process analogous to organic evolution has been discussed for over 100 years. A recently proposed theory instantiates this idea by means of a genetic algorithm that operates on a population of potential behaviors. Behaviors in the population are represented by numbers in decimal integer (phenotypic) and binary bit string (genotypic) forms. One behavior from the population is emitted at random each time tick, after which a new population of potential behaviors is constructed by recombining parent behavior bit strings. If the emitted behavior produced a benefit to the organism, then parents are chosen on the basis of their phenotypic similarity to the emitted behavior; otherwise, they are chosen at random. After parent behavior recombination, the population is subjected to a small amount of mutation by flipping random bits in the population's bit strings. The behavior generated by this process of selection, reproduction, and mutation reaches equilibrium states that conform to every empirically valid equation of matching theory, exactly and without systematic error. These equations are known to describe the behavior of many vertebrate species, including humans, in a variety of experimental, naturalistic, natural, and social environments. The evolutionary theory also generates instantaneous dynamics and patterns of preference change in constantly changing environments that are consistent with the dynamics of live-organism behavior. These findings support the assertion that the world of behavior we observe and measure is generated by evolutionary dynamics. PMID:24219847

  9. Self Adaptive High Interaction Honeypots Driven by Game Theory

    NASA Astrophysics Data System (ADS)

    Wagener, Gérard; State, Radu; Dulaunoy, Alexandre; Engel, Thomas

    High-interaction honeypots are relevant to provide rich and useful information obtained from attackers. Honeypots come in different flavors with respect to their interaction potential. A honeypot can be very restrictive, but then only a few interactions can be observed. If a honeypot is very tolerant though, attackers can quickly achieve their goal. Having the best trade-off between attacker freedom and honeypot restrictions is challenging. In this paper, we address the issue of self adaptive honeypots, that can change their behavior and lure attackers into revealing as much information as possible about themselves. The key idea is to leverage game-theoretic concepts for the configuration and reciprocal actions of high-interaction honeypots.

  10. 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

  11. 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. PMID:26645306

  12. Exploring Multiple Intelligences Theory at a Community College Level.

    ERIC Educational Resources Information Center

    Berkemeier, Ginny Y. Hew

    Discusses multiple intelligence (a pluralized approach to understanding the intellect) teaching and learning of science at the higher education level, specifically within community colleges. The purpose of this study was four-fold. The first purpose was to investigate adult learning through Multiple Intelligence Theory (MI) at the community…

  13. Metacognitive Theory and Levels of History Department Students, Karabuk University

    ERIC Educational Resources Information Center

    Candan, Ahmet Sait

    2012-01-01

    This paper aims to study the levels of metacognition of students of History Department of Karabuk University and whether they differ according to their variables terms. Screening model was used in this study. Basic information about the concept of metacognition and metacognitive theory from movement of national and international literature were…

  14. Microevolutionary, macroevolutionary, ecological and taxonomical implications of punctuational theories of adaptive evolution

    PubMed Central

    2013-01-01

    Abstract Punctuational theories of evolution suggest that adaptive evolution proceeds mostly, or even entirely, in the distinct periods of existence of a particular species. The mechanisms of this punctuated nature of evolution suggested by the various theories differ. Therefore the predictions of particular theories concerning various evolutionary phenomena also differ. Punctuational theories can be subdivided into five classes, which differ in their mechanism and their evolutionary and ecological implications. For example, the transilience model of Templeton (class III), genetic revolution model of Mayr (class IV) or the frozen plasticity theory of Flegr (class V), suggests that adaptive evolution in sexual species is operative shortly after the emergence of a species by peripatric speciation – while it is evolutionary plastic. To a major degree, i.e. throughout 98-99% of their existence, sexual species are evolutionarily frozen (class III) or elastic (class IV and V) on a microevolutionary time scale and evolutionarily frozen on a macroevolutionary time scale and can only wait for extinction, or the highly improbable return of a population segment to the plastic state due to peripatric speciation. The punctuational theories have many evolutionary and ecological implications. Most of these predictions could be tested empirically, and should be analyzed in greater depth theoretically. The punctuational theories offer many new predictions that need to be tested, but also provide explanations for a much broader spectrum of known biological phenomena than classical gradualistic evolutionary theories. Reviewers This article was reviewed by Claus Wilke, Pierre Pantarotti and David Penny (nominated by Anthony Poole). PMID:23324625

  15. Computerized Adaptive Testing, Anxiety Levels, and Gender Differences

    ERIC Educational Resources Information Center

    Fritts, Barbara E.; Marszalek, Jacob M.

    2010-01-01

    This study compares the amount of test anxiety experienced on a computerized adaptive test (CAT) to a paper-and-pencil test (P&P), as well as the state test anxiety experienced between males and females. Ninety-four middle school CAT examinees were compared to 65 middle school P&P examinees on their responses to the State-Trait Anxiety Inventory…

  16. Seeing Coloured Fruits: Utilisation of the Theory of Adaptive Memory in Teaching Botany

    ERIC Educational Resources Information Center

    Prokop, Pavol; Fancovicová, Jana

    2014-01-01

    Plants are characterised by a great diversity of easily observed features such as colours or shape, but children show low interest in learning about them. Here, we integrated modern theory of adaptive memory and evolutionary views of the function of fruit colouration on children's retention of information. Survival-relevant (fruit toxicity)…

  17. Rhetorical Dissent as an Adaptive Response to Classroom Problems: A Test of Protection Motivation Theory

    ERIC Educational Resources Information Center

    Bolkan, San; Goodboy, Alan K.

    2016-01-01

    Protection motivation theory (PMT) explains people's adaptive behavior in response to personal threats. In this study, PMT was used to predict rhetorical dissent episodes related to 210 student reports of perceived classroom problems. In line with theoretical predictions, a moderated moderation analysis revealed that students were likely to voice…

  18. 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…

  19. Computerized Adaptive Testing Using a Class of High-Order Item Response Theory Models

    ERIC Educational Resources Information Center

    Huang, Hung-Yu; Chen, Po-Hsi; Wang, Wen-Chung

    2012-01-01

    In the human sciences, a common assumption is that latent traits have a hierarchical structure. Higher order item response theory models have been developed to account for this hierarchy. In this study, computerized adaptive testing (CAT) algorithms based on these kinds of models were implemented, and their performance under a variety of…

  20. Micro-Level Adaptation, Macro-Level Selection, and the Dynamics of Market Partitioning.

    PubMed

    García-Díaz, César; van Witteloostuijn, Arjen; Péli, Gábor

    2015-01-01

    This paper provides a micro-foundation for dual market structure formation through partitioning processes in marketplaces by developing a computational model of interacting economic agents. We propose an agent-based modeling approach, where firms are adaptive and profit-seeking agents entering into and exiting from the market according to their (lack of) profitability. Our firms are characterized by large and small sunk costs, respectively. They locate their offerings along a unimodal demand distribution over a one-dimensional product variety, with the distribution peak constituting the center and the tails standing for the peripheries. We found that large firms may first advance toward the most abundant demand spot, the market center, and release peripheral positions as predicted by extant dual market explanations. However, we also observed that large firms may then move back toward the market fringes to reduce competitive niche overlap in the center, triggering nonlinear resource occupation behavior. Novel results indicate that resource release dynamics depend on firm-level adaptive capabilities, and that a minimum scale of production for low sunk cost firms is key to the formation of the dual structure. PMID:26656107

  1. Micro-Level Adaptation, Macro-Level Selection, and the Dynamics of Market Partitioning

    PubMed Central

    García-Díaz, César; van Witteloostuijn, Arjen; Péli, Gábor

    2015-01-01

    This paper provides a micro-foundation for dual market structure formation through partitioning processes in marketplaces by developing a computational model of interacting economic agents. We propose an agent-based modeling approach, where firms are adaptive and profit-seeking agents entering into and exiting from the market according to their (lack of) profitability. Our firms are characterized by large and small sunk costs, respectively. They locate their offerings along a unimodal demand distribution over a one-dimensional product variety, with the distribution peak constituting the center and the tails standing for the peripheries. We found that large firms may first advance toward the most abundant demand spot, the market center, and release peripheral positions as predicted by extant dual market explanations. However, we also observed that large firms may then move back toward the market fringes to reduce competitive niche overlap in the center, triggering nonlinear resource occupation behavior. Novel results indicate that resource release dynamics depend on firm-level adaptive capabilities, and that a minimum scale of production for low sunk cost firms is key to the formation of the dual structure. PMID:26656107

  2. Theory of Energy Level Tuning in Quantum Dots by Surfactants

    NASA Astrophysics Data System (ADS)

    Zherebetskyy, Danylo; Wang, Lin-Wang; Materials Sciences Division, Lawrence Berkeley National Laboratory Team

    2015-03-01

    Besides quantum confinement that provides control of the quantum dot (QD) band gap, surface ligands allow control of the absolute energy levels. We theoretically investigate energy level tuning in PbS QD by surfactant exchange. We perform direct calculations of real-size QD with various surfactants within the frame of the density functional theory and explicitly analyze the influence of the surfactants on the electronic properties of the QD. This work provides a hint for predictable control of the absolute energy levels and their fine tuning within 3 eV range by modification of big and small surfactants that simultaneously passivate the QD surface.

  3. Using Out-of-Level Items in Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Wei, Hua; Lin, Jie

    2015-01-01

    Out-of-level testing refers to the practice of assessing a student with a test that is intended for students at a higher or lower grade level. Although the appropriateness of out-of-level testing for accountability purposes has been questioned by educators and policymakers, incorporating out-of-level items in formative assessments for accurate…

  4. The social neuroscience and the theory of integrative levels

    PubMed Central

    Bello-Morales, Raquel; Delgado-García, José María

    2015-01-01

    The theory of integrative levels provides a general description of the evolution of matter through successive orders of complexity and integration. Along its development, material forms pass through different levels of organization, such as physical, chemical, biological or sociological. The appearance of novel structures and dynamics during this process of development of matter in complex systems has been called emergence. Social neuroscience (SN), an interdisciplinary field that aims to investigate the biological mechanisms that underlie social structures, processes, and behavior and the influences between social and biological levels of organization, has affirmed the necessity for including social context as an essential element to understand the human behavior. To do this, SN proposes a multilevel integrative approach by means of three principles: multiple determinism, nonadditive determinism and reciprocal determinism. These theoretical principles seem to share the basic tenets of the theory of integrative levels but, in this paper, we aim to reveal the differences among both doctrines. First, SN asserts that combination of neural and social variables can produce emergent phenomena that would not be predictable from a neuroscientific or social psychological analysis alone; SN also suggests that to achieve a complete understanding of social structures we should use an integrative analysis that encompasses levels of organization ranging from the genetic level to the social one; finally, SN establishes that there can be mutual influences between biological and social factors in determining behavior, accepting, therefore, a double influence, upward from biology to social level, and downward, from social level to biology. In contrast, following the theory of integrative levels, emergent phenomena are not produced by the combination of variables from two levels, but by the increment of complexity at one level. In addition, the social behavior and structures might be

  5. Effect of a care plan based on Roy adaptation model biological dimension on stroke patients’ physiologic adaptation level

    PubMed Central

    Alimohammadi, Nasrollah; Maleki, Bibi; Shahriari, Mohsen; Chitsaz, Ahmad

    2015-01-01

    Background: Stroke is a stressful event with several functional, physical, psychological, social, and economic problems that affect individuals’ different living balances. With coping strategies, patients try to control these problems and return to their natural life. The aim of this study is to investigate the effect of a care plan based on Roy adaptation model biological dimension on stroke patients’ physiologic adaptation level. Materials and Methods: This study is a clinical trial in which 50 patients, affected by brain stroke and being admitted in the neurology ward of Kashani and Alzahra hospitals, were randomly assigned to control and study groups in Isfahan in 2013. Roy adaptation model care plan was administered in biological dimension in the form of four sessions and phone call follow-ups for 1 month. The forms related to Roy adaptation model were completed before and after intervention in the two groups. Chi-square test and t-test were used to analyze the data through SPSS 18. Results: There was a significant difference in mean score of adaptation in physiological dimension in the study group after intervention (P < 0.001) compared to before intervention. Comparison of the mean scores of changes of adaptation in the patients affected by brain stroke in the study and control groups showed a significant increase in physiological dimension in the study group by 47.30 after intervention (P < 0.001). Conclusions: The results of study showed that Roy adaptation model biological dimension care plan can result in an increase in adaptation in patients with stroke in physiological dimension. Nurses can use this model for increasing patients’ adaptation. PMID:25878708

  6. Designing for adaptation to novelty and change: functional information, emergent feature graphics, and higher-level control.

    PubMed

    Hajdukiewicz, John R; Vicente, Kim J

    2002-01-01

    Ecological interface design (EID) is a theoretical framework that aims to support worker adaptation to change and novelty in complex systems. Previous evaluations of EID have emphasized representativeness to enhance generalizability of results to operational settings. The research presented here is complementary, emphasizing experimental control to enhance theory building. Two experiments were conducted to test the impact of functional information and emergent feature graphics on adaptation to novelty and change in a thermal-hydraulic process control microworld. Presenting functional information in an interface using emergent features encouraged experienced participants to become perceptually coupled to the interface and thereby to exhibit higher-level control and more successful adaptation to unanticipated events. The absence of functional information or of emergent features generally led to lower-level control and less success at adaptation, the exception being a minority of participants who compensated by relying on analytical reasoning. These findings may have practical implications for shaping coordination in complex systems and fundamental implications for the development of a general unified theory of coordination for the technical, human, and social sciences. Actual or potential applications of this research include the design of human-computer interfaces that improve safety in complex sociotechnical systems. PMID:12691368

  7. Coastal Adaptation Planning for Sea Level Rise and Extremes: A Global Model for Adaptation Decision-making at the Local Level Given Uncertain Climate Projections

    NASA Astrophysics Data System (ADS)

    Turner, D.

    2014-12-01

    Understanding the potential economic and physical impacts of climate change on coastal resources involves evaluating a number of distinct adaptive responses. This paper presents a tool for such analysis, a spatially-disaggregated optimization model for adaptation to sea level rise (SLR) and storm surge, the Coastal Impact and Adaptation Model (CIAM). This decision-making framework fills a gap between very detailed studies of specific locations and overly aggregate global analyses. While CIAM is global in scope, the optimal adaptation strategy is determined at the local level, evaluating over 12,000 coastal segments as described in the DIVA database (Vafeidis et al. 2006). The decision to pursue a given adaptation measure depends on local socioeconomic factors like income, population, and land values and how they develop over time, relative to the magnitude of potential coastal impacts, based on geophysical attributes like inundation zones and storm surge. For example, the model's decision to protect or retreat considers the costs of constructing and maintaining coastal defenses versus those of relocating people and capital to minimize damages from land inundation and coastal storms. Uncertain storm surge events are modeled with a generalized extreme value distribution calibrated to data on local surge extremes. Adaptation is optimized for the near-term outlook, in an "act then learn then act" framework that is repeated over the model time horizon. This framework allows the adaptation strategy to be flexibly updated, reflecting the process of iterative risk management. CIAM provides new estimates of the economic costs of SLR; moreover, these detailed results can be compactly represented in a set of adaptation and damage functions for use in integrated assessment models. Alongside the optimal result, CIAM evaluates suboptimal cases and finds that global costs could increase by an order of magnitude, illustrating the importance of adaptive capacity and coastal policy.

  8. Lithofacies identification using multiple adaptive resonance theory neural networks and group decision expert system

    USGS Publications Warehouse

    Chang, H.-C.; Kopaska-Merkel, D. C.; Chen, H.-C.; Rocky, Durrans S.

    2000-01-01

    Lithofacies identification supplies qualitative information about rocks. Lithofacies represent rock textures and are important components of hydrocarbon reservoir description. Traditional techniques of lithofacies identification from core data are costly and different geologists may provide different interpretations. In this paper, we present a low-cost intelligent system consisting of three adaptive resonance theory neural networks and a rule-based expert system to consistently and objectively identify lithofacies from well-log data. The input data are altered into different forms representing different perspectives of observation of lithofacies. Each form of input is processed by a different adaptive resonance theory neural network. Among these three adaptive resonance theory neural networks, one neural network processes the raw continuous data, another processes categorial data, and the third processes fuzzy-set data. Outputs from these three networks are then combined by the expert system using fuzzy inference to determine to which facies the input data should be assigned. Rules are prioritized to emphasize the importance of firing order. This new approach combines the learning ability of neural networks, the adaptability of fuzzy logic, and the expertise of geologists to infer facies of the rocks. This approach is applied to the Appleton Field, an oil field located in Escambia County, Alabama. The hybrid intelligence system predicts lithofacies identity from log data with 87.6% accuracy. This prediction is more accurate than those of single adaptive resonance theory networks, 79.3%, 68.0% and 66.0%, using raw, fuzzy-set, and categorical data, respectively, and by an error-backpropagation neural network, 57.3%. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.

  9. Lithofacies identification using multiple adaptive resonance theory neural networks and group decision expert system

    NASA Astrophysics Data System (ADS)

    Chang, Hsien-cheng; Kopaska-Merkel, David C.; Chen, Hui-Chuan; Durrans, S. Rocky

    2000-06-01

    Lithofacies identification supplies qualitative information about rocks. Lithofacies represent rock textures and are important components of hydrocarbon reservoir description. Traditional techniques of lithofacies identification from core data are costly and different geologists may provide different interpretations. In this paper, we present a low-cost intelligent system consisting of three adaptive resonance theory neural networks and a rule-based expert system to consistently and objectively identify lithofacies from well-log data. The input data are altered into different forms representing different perspectives of observation of lithofacies. Each form of input is processed by a different adaptive resonance theory neural network. Among these three adaptive resonance theory neural networks, one neural network processes the raw continuous data, another processes categorical data, and the third processes fuzzy-set data. Outputs from these three networks are then combined by the expert system using fuzzy inference to determine to which facies the input data should be assigned. Rules are prioritized to emphasize the importance of firing order. This new approach combines the learning ability of neural networks, the adaptability of fuzzy logic, and the expertise of geologists to infer facies of the rocks. This approach is applied to the Appleton Field, an oil field located in Escambia County, Alabama. The hybrid intelligence system predicts lithofacies identity from log data with 87.6% accuracy. This prediction is more accurate than those of single adaptive resonance theory networks, 79.3%, 68.0% and 66.0%, using raw, fuzzy-set, and categorical data, respectively, and by an error-backpropagation neural network, 57.3%.

  10. An Adaptive Resonance Theory account of the implicit learning of orthographic word forms.

    PubMed

    Glotin, H; Warnier, P; Dandurand, F; Dufau, S; Lété, B; Touzet, C; Ziegler, J C; Grainger, J

    2010-01-01

    An Adaptive Resonance Theory (ART) network was trained to identify unique orthographic word forms. Each word input to the model was represented as an unordered set of ordered letter pairs (open bigrams) that implement a flexible prelexical orthographic code. The network learned to map this prelexical orthographic code onto unique word representations (orthographic word forms). The network was trained on a realistic corpus of reading textbooks used in French primary schools. The amount of training was strictly identical to children's exposure to reading material from grade 1 to grade 5. Network performance was examined at each grade level. Adjustment of the learning and vigilance parameters of the network allowed us to reproduce the developmental growth of word identification performance seen in children. The network exhibited a word frequency effect and was found to be sensitive to the order of presentation of word inputs, particularly with low frequency words. These words were better learned with a randomized presentation order compared with the order of presentation in the school books. These results open up interesting perspectives for the application of ART networks in the study of the dynamics of learning to read. PMID:19903528

  11. Advances in adaptive control theory: Gradient- and derivative-free approaches

    NASA Astrophysics Data System (ADS)

    Yucelen, Tansel

    In this dissertation, we present new approaches to improve standard designs in adaptive control theory, and novel adaptive control architectures. We first present a novel Kalman filter based approach for approximately enforcing a linear constraint in standard adaptive control design. One application is that this leads to alternative forms for well known modification terms such as e-modification. In addition, it leads to smaller tracking errors without incurring significant oscillations in the system response and without requiring high modification gain. We derive alternative forms of e- and adaptive loop recovery (ALR-) modifications. Next, we show how to use Kalman filter optimization to derive a novel adaptation law. This results in an optimization-based time-varying adaptation gain that reduces the need for adaptation gain tuning. A second major contribution of this dissertation is the development of a novel derivative-free, delayed weight update law for adaptive control. The assumption of constant unknown ideal weights is relaxed to the existence of time-varying weights, such that fast and possibly discontinuous variation in weights are allowed. This approach is particulary advantageous for applications to systems that can undergo a sudden change in dynamics, such as might be due to reconfiguration, deployment of a payload, docking, or structural damage, and for rejection of external disturbance processes. As a third and final contribution, we develop a novel approach for extending all the methods developed in this dissertation to the case of output feedback. The approach is developed only for the case of derivative-free adaptive control, and the extension of the other approaches developed previously for the state feedback case to output feedback is left as a future research topic. The proposed approaches of this dissertation are illustrated in both simulation and flight test.

  12. Effects of Crowding and Attention on High-Levels of Motion Processing and Motion Adaptation

    PubMed Central

    Pavan, Andrea; Greenlee, Mark W.

    2015-01-01

    The motion after-effect (MAE) persists in crowding conditions, i.e., when the adaptation direction cannot be reliably perceived. The MAE originating from complex moving patterns spreads into non-adapted sectors of a multi-sector adapting display (i.e., phantom MAE). In the present study we used global rotating patterns to measure the strength of the conventional and phantom MAEs in crowded and non-crowded conditions, and when attention was directed to the adapting stimulus and when it was diverted away from the adapting stimulus. The results show that: (i) the phantom MAE is weaker than the conventional MAE, for both non-crowded and crowded conditions, and when attention was focused on the adapting stimulus and when it was diverted from it, (ii) conventional and phantom MAEs in the crowded condition are weaker than in the non-crowded condition. Analysis conducted to assess the effect of crowding on high-level of motion adaptation suggests that crowding is likely to affect the awareness of the adapting stimulus rather than degrading its sensory representation, (iii) for high-level of motion processing the attentional manipulation does not affect the strength of either conventional or phantom MAEs, neither in the non-crowded nor in the crowded conditions. These results suggest that high-level MAEs do not depend on attention and that at high-level of motion adaptation the effects of crowding are not modulated by attention. PMID:25615577

  13. REVIEW: Internal models in sensorimotor integration: perspectives from adaptive control theory

    NASA Astrophysics Data System (ADS)

    Tin, Chung; Poon, Chi-Sang

    2005-09-01

    Internal models and adaptive controls are empirical and mathematical paradigms that have evolved separately to describe learning control processes in brain systems and engineering systems, respectively. This paper presents a comprehensive appraisal of the correlation between these paradigms with a view to forging a unified theoretical framework that may benefit both disciplines. It is suggested that the classic equilibrium-point theory of impedance control of arm movement is analogous to continuous gain-scheduling or high-gain adaptive control within or across movement trials, respectively, and that the recently proposed inverse internal model is akin to adaptive sliding control originally for robotic manipulator applications. Modular internal models' architecture for multiple motor tasks is a form of multi-model adaptive control. Stochastic methods, such as generalized predictive control, reinforcement learning, Bayesian learning and Hebbian feedback covariance learning, are reviewed and their possible relevance to motor control is discussed. Possible applicability of a Luenberger observer and an extended Kalman filter to state estimation problems—such as sensorimotor prediction or the resolution of vestibular sensory ambiguity—is also discussed. The important role played by vestibular system identification in postural control suggests an indirect adaptive control scheme whereby system states or parameters are explicitly estimated prior to the implementation of control. This interdisciplinary framework should facilitate the experimental elucidation of the mechanisms of internal models in sensorimotor systems and the reverse engineering of such neural mechanisms into novel brain-inspired adaptive control paradigms in future.

  14. On residual stresses and homeostasis: an elastic theory of functional adaptation in living matter

    NASA Astrophysics Data System (ADS)

    Ciarletta, P.; Destrade, M.; Gower, A. L.

    2016-04-01

    Living matter can functionally adapt to external physical factors by developing internal tensions, easily revealed by cutting experiments. Nonetheless, residual stresses intrinsically have a complex spatial distribution, and destructive techniques cannot be used to identify a natural stress-free configuration. This work proposes a novel elastic theory of pre-stressed materials. Imposing physical compatibility and symmetry arguments, we define a new class of free energies explicitly depending on the internal stresses. This theory is finally applied to the study of arterial remodelling, proving its potential for the non-destructive determination of the residual tensions within biological materials.

  15. On residual stresses and homeostasis: an elastic theory of functional adaptation in living matter.

    PubMed

    Ciarletta, P; Destrade, M; Gower, A L

    2016-01-01

    Living matter can functionally adapt to external physical factors by developing internal tensions, easily revealed by cutting experiments. Nonetheless, residual stresses intrinsically have a complex spatial distribution, and destructive techniques cannot be used to identify a natural stress-free configuration. This work proposes a novel elastic theory of pre-stressed materials. Imposing physical compatibility and symmetry arguments, we define a new class of free energies explicitly depending on the internal stresses. This theory is finally applied to the study of arterial remodelling, proving its potential for the non-destructive determination of the residual tensions within biological materials. PMID:27113413

  16. On residual stresses and homeostasis: an elastic theory of functional adaptation in living matter

    PubMed Central

    Ciarletta, P.; Destrade, M.; Gower, A. L.

    2016-01-01

    Living matter can functionally adapt to external physical factors by developing internal tensions, easily revealed by cutting experiments. Nonetheless, residual stresses intrinsically have a complex spatial distribution, and destructive techniques cannot be used to identify a natural stress-free configuration. This work proposes a novel elastic theory of pre-stressed materials. Imposing physical compatibility and symmetry arguments, we define a new class of free energies explicitly depending on the internal stresses. This theory is finally applied to the study of arterial remodelling, proving its potential for the non-destructive determination of the residual tensions within biological materials. PMID:27113413

  17. Quantum Information Biology: From Theory of Open Quantum Systems to Adaptive Dynamics

    NASA Astrophysics Data System (ADS)

    Asano, Masanari; Basieva, Irina; Khrennikov, Andrei; Ohya, Masanori; Tanaka, Yoshiharu; Yamato, Ichiro

    This chapter reviews quantum(-like) information biology (QIB). Here biology is treated widely as even covering cognition and its derivatives: psychology and decision making, sociology, and behavioral economics and finances. QIB provides an integrative description of information processing by bio-systems at all scales of life: from proteins and cells to cognition, ecological and social systems. Mathematically QIB is based on the theory of adaptive quantum systems (which covers also open quantum systems). Ideologically QIB is based on the quantum-like (QL) paradigm: complex bio-systems process information in accordance with the laws of quantum information and probability. This paradigm is supported by plenty of statistical bio-data collected at all bio-scales. QIB re ects the two fundamental principles: a) adaptivity; and, b) openness (bio-systems are fundamentally open). In addition, quantum adaptive dynamics provides the most generally possible mathematical representation of these principles.

  18. Effective Levels of Adaptation to Different Types of Users in Interactive Museum Systems.

    ERIC Educational Resources Information Center

    Paterno, F.; Mancini, C.

    2000-01-01

    Discusses user interaction with museum application interfaces and emphasizes the importance of adaptable and adaptive interfaces to meet differing user needs. Considers levels of support that can be given to different users during navigation of museum hypermedia information, using examples from the Web site for the Marble Museum (Italy).…

  19. Flicker Adaptation of Low-Level Cortical Visual Neurons Contributes to Temporal Dilation

    ERIC Educational Resources Information Center

    Ortega, Laura; Guzman-Martinez, Emmanuel; Grabowecky, Marcia; Suzuki, Satoru

    2012-01-01

    Several seconds of adaptation to a flickered stimulus causes a subsequent brief static stimulus to appear longer in duration. Nonsensory factors, such as increased arousal and attention, have been thought to mediate this flicker-based temporal-dilation aftereffect. In this study, we provide evidence that adaptation of low-level cortical visual…

  20. Adaptation of the Illness Trajectory Theory to Describe the Work of Transitional Cancer Survivorship

    PubMed Central

    Klimmek, Rachel; Wenzel, Jennifer

    2013-01-01

    Purpose/Objectives Although frameworks for understanding survivorship continue to evolve, most are abstract and do not address the complex context of survivors’ transition following treatment completion. The purpose of this theory adaptation was to examine and refine the Illness Trajectory Theory, which describes the work of managing chronic illness, to address transitional cancer survivorship. Data Sources CINAHL, PubMed, and relevant Institute of Medicine reports were searched for survivors’ experiences during the year following treatment. Data Synthesis Using an abstraction tool, sixty-eight articles were selected from the initial search (N>700). Abstracted data were placed into a priori categories refined according to recommended procedures for theory derivation, followed by expert review. Conclusions Derivation resulted in a framework describing “the work of transitional cancer survivorship” (TCS work). TCS work is defined as survivor tasks, performed alone or with others, to carry out a plan of action for managing one or more aspects of life following primary cancer treatment. Theoretically, survivors engage in 3 reciprocally-interactive lines of work: (1) illness-related; (2) biographical; and (3) everyday life work. Adaptation resulted in refinement of these domains and the addition of survivorship care planning under “illness-related work”. Implications for Nursing Understanding this process of work may allow survivors/co-survivors to better prepare for the post-treatment period. This adaptation provides a framework for future testing and development. Validity and utility of this framework within specific survivor populations should also be explored. PMID:23107863

  1. Incorporating Midbrain Adaptation to Mean Sound Level Improves Models of Auditory Cortical Processing

    PubMed Central

    Schoppe, Oliver; King, Andrew J.; Schnupp, Jan W.H.; Harper, Nicol S.

    2016-01-01

    Adaptation to stimulus statistics, such as the mean level and contrast of recently heard sounds, has been demonstrated at various levels of the auditory pathway. It allows the nervous system to operate over the wide range of intensities and contrasts found in the natural world. Yet current standard models of the response properties of auditory neurons do not incorporate such adaptation. Here we present a model of neural responses in the ferret auditory cortex (the IC Adaptation model), which takes into account adaptation to mean sound level at a lower level of processing: the inferior colliculus (IC). The model performs high-pass filtering with frequency-dependent time constants on the sound spectrogram, followed by half-wave rectification, and passes the output to a standard linear–nonlinear (LN) model. We find that the IC Adaptation model consistently predicts cortical responses better than the standard LN model for a range of synthetic and natural stimuli. The IC Adaptation model introduces no extra free parameters, so it improves predictions without sacrificing parsimony. Furthermore, the time constants of adaptation in the IC appear to be matched to the statistics of natural sounds, suggesting that neurons in the auditory midbrain predict the mean level of future sounds and adapt their responses appropriately. SIGNIFICANCE STATEMENT An ability to accurately predict how sensory neurons respond to novel stimuli is critical if we are to fully characterize their response properties. Attempts to model these responses have had a distinguished history, but it has proven difficult to improve their predictive power significantly beyond that of simple, mostly linear receptive field models. Here we show that auditory cortex receptive field models benefit from a nonlinear preprocessing stage that replicates known adaptation properties of the auditory midbrain. This improves their predictive power across a wide range of stimuli but keeps model complexity low as it

  2. Building a conceptual framework to culturally adapt health promotion and prevention programs at the deep structural level.

    PubMed

    Wang-Schweig, Meme; Kviz, Frederick J; Altfeld, Susan J; Miller, Arlene M; Miller, Brenda A

    2014-07-01

    The debate on the effectiveness and merit for the amount of time, effort, and resources to culturally adapt health promotion and prevention programs continues. This may be due, in large part, to the lack of theory in commonly used methods to match programmatic content and delivery to the culture of a population, particularly at the deep structural level. This paper asserts that prior to the cultural adaptation of prevention programs, it is necessary to first develop a conceptual framework. We propose a multiphase approach to address key challenges in the science of cultural adaptation by first identifying and exploring relevant cultural factors that may affect the targeted health-related behavior prior to proceeding through steps of a stage model. The first phase involves developing an underlying conceptual framework that integrates cultural factors to ground this process. The second phase employs the different steps of a stage model. For Phase I of our approach, we offer four key steps and use our research study as an example of how these steps were applied to build a framework for the cultural adaptation of a family-based intervention to prevent adolescent alcohol use, Guiding Good Choices (GGC), to Chinese American families. We then provide a summary of the preliminary evidence from a few key relationships that were tested among our sample with the greater purpose of discussing how these findings might be used to culturally adapt GGC. PMID:24396122

  3. Representation Theory of the Affine Lie Superalgebra at Fractional Level

    NASA Astrophysics Data System (ADS)

    Bowcock, P.; Taormina, A.

    N= 2 noncritical strings are closely related to the Wess-Zumino-Novikov-Witten model, and there is much hope to further probe the former by using the algebraic apparatus provided by the latter. An important ingredient is the precise knowledge of the representation theory at fractional level. In this paper, the embedding diagrams of singular vectors appearing in Verma modules for fractional values of the level ( , p and q coprime) are derived analytically. The nilpotency of the fermionic generators in requires the introduction of a nontrivial generalisation of the MFF construction to relate singular vectors among themselves. The diagrams reveal a striking similarity with the degenerate representations of the N= 2 superconformal algebra.

  4. Exploring multiple intelligences theory at a community college level

    NASA Astrophysics Data System (ADS)

    Berkemeier, Ginny Y. Hew

    The publication of "Frames of mind: The theory in practice", (Gardner, 1983) has been used by educators in a variety of ways to make teaching and learning more meaningful. However, little attention has been focused on the MI teaching and learning of science at the higher education level. Consequently, the purpose of this study was four fold. The first purpose was to investigate adult learning through Multiple Intelligence Theory (MI) at the community college level. The second purpose was to determine where there were any differences among students in their perceived MI with regard to age and gender. The third purpose was to investigate the relationship between perceived and tested MI strength with regard to science and non-science courses. The fourth purpose was to determine which MI teaching value relates best with science and non-science courses. Study participants were enrolled in science courses from a Midwestern community college, Ozarks Technical Community College (OTC). The research methodology of this research study consisted of a combination of quantitative analysis; using an inventory and qualitative analysis; through group interviews. Many positive outcomes resulted from the study in areas such as the relationships between tested MI and perceived MI, student learning in science and non-science courses, and their relationships to age and gender. This study suggested the need for a variety of education and curriculum reform that should start with students' attitudes instead of classroom instruction or methods of teaching.

  5. Dynamic Range Adaptation to Sound Level Statistics in the Auditory Nerve

    PubMed Central

    Wen, Bo; Wang, Grace I.; Dean, Isabel; Delgutte, Bertrand

    2009-01-01

    The auditory system operates over a vast range of sound pressure levels (100–120 dB) with nearly constant discrimination ability across most of the range, well exceeding the dynamic range of most auditory neurons (20–40 dB). Dean et al. (Nat. Neurosci. 8:1684, 2005) have reported that the dynamic range of midbrain auditory neurons adapts to the distribution of sound levels in a continuous, dynamic stimulus by shifting towards the most frequently occurring level. Here we show that dynamic range adaptation, distinct from classic firing rate adaptation, also occurs in primary auditory neurons in anesthetized cats for tone and noise stimuli. Specifically, the range of sound levels over which firing rates of auditory-nerve (AN) fibers grows rapidly with level shifts nearly linearly with the most probable levels in a dynamic sound stimulus. This dynamic range adaptation was observed for fibers with all characteristic frequencies and spontaneous discharge rates. As in the midbrain, dynamic range adaptation improved the precision of level coding by the AN fiber population for the prevailing sound levels in the stimulus. However, dynamic range adaptation in the AN was weaker than in the midbrain, and not sufficient (0.25 dB/dB on average for broadband noise) to prevent a significant degradation of the precision of level coding by the AN population above 60 dB SPL. These findings suggest that adaptive processing of sound levels first occurs in the auditory periphery and is enhanced along the auditory pathway. PMID:19889991

  6. Multi-level adaptive finite element methods. 1: Variation problems

    NASA Technical Reports Server (NTRS)

    Brandt, A.

    1979-01-01

    A general numerical strategy for solving partial differential equations and other functional problems by cycling between coarser and finer levels of discretization is described. Optimal discretization schemes are provided together with very fast general solvers. It is described in terms of finite element discretizations of general nonlinear minimization problems. The basic processes (relaxation sweeps, fine-grid-to-coarse-grid transfers of residuals, coarse-to-fine interpolations of corrections) are directly and naturally determined by the objective functional and the sequence of approximation spaces. The natural processes, however, are not always optimal. Concrete examples are given and some new techniques are reviewed. Including the local truncation extrapolation and a multilevel procedure for inexpensively solving chains of many boundary value problems, such as those arising in the solution of time-dependent problems.

  7. Low Level Waste Conceptual Design Adaption to Poor Geological Conditions

    SciTech Connect

    Bell, J.; Drimmer, D.; Giovannini, A.; Manfroy, P.; Maquet, F.; Schittekat, J.; Van Cotthem, A.; Van Echelpoel, E.

    2002-02-26

    Since the early eighties, several studies have been carried out in Belgium with respect to a repository for the final disposal of low-level radioactive waste (LLW). In 1998, the Belgian Government decided to restrict future investigations to the four existing nuclear sites in Belgium or sites that might show interest. So far, only two existing nuclear sites have been thoroughly investigated from a geological and hydrogeological point of view. These sites are located in the North-East (Mol-Dessel) and in the mid part (Fleurus-Farciennes) of the country. Both sites have the disadvantage of presenting poor geological and hydrogeological conditions, which are rather unfavorable to accommodate a surface disposal facility for LLW. The underground of the Mol-Dessel site consists of neogene sand layers of about 180 m thick which cover a 100 meters thick clay layer. These neogene sands contain, at 20 m depth, a thin clayey layer. The groundwater level is quite close to the surface (0-2m) and finally, the topography is almost totally flat. The upper layer of the Fleurus-Farciennes site consists of 10 m silt with poor geomechanical characteristics, overlying sands (only a few meters thick) and Westphalian shales between 15 and 20 m depth. The Westphalian shales are tectonized and strongly weathered. In the past, coal seams were mined out. This activity induced locally important surface subsidence. For both nuclear sites that were investigated, a conceptual design was made that could allow any unfavorable geological or hydrogeological conditions of the site to be overcome. In Fleurus-Farciennes, for instance, the proposed conceptual design of the repository is quite original. It is composed of a shallow, buried concrete cylinder, surrounded by an accessible concrete ring, which allows permanent inspection and control during the whole lifetime of the repository. Stability and drainage systems should be independent of potential differential settlements an d subsidences

  8. Adaptive modeling, identification, and control of dynamic structural systems. I. Theory

    USGS Publications Warehouse

    Safak, Erdal

    1989-01-01

    A concise review of the theory of adaptive modeling, identification, and control of dynamic structural systems based on discrete-time recordings is presented. Adaptive methods have four major advantages over the classical methods: (1) Removal of the noise from the signal is done over the whole frequency band; (2) time-varying characteristics of systems can be tracked; (3) systems with unknown characteristics can be controlled; and (4) a small segment of the data is needed during the computations. Included in the paper are the discrete-time representation of single-input single-output (SISO) systems, models for SISO systems with noise, the concept of stochastic approximation, recursive prediction error method (RPEM) for system identification, and the adaptive control. Guidelines for model selection and model validation and the computational aspects of the method are also discussed in the paper. The present paper is the first of two companion papers. The theory given in the paper is limited to that which is necessary to follow the examples for applications in structural dynamics presented in the second paper.

  9. Farm level adaptation to climate change: the case of farmer's in the Ethiopian highlands.

    PubMed

    Gebrehiwot, Tagel; van der Veen, Anne

    2013-07-01

    In Ethiopia, climate change and associated risks are expected to have serious consequences for agriculture and food security. This in turn will seriously impact on the welfare of the people, particularly the rural farmers whose main livelihood depends on rain-fed agriculture. The level of impacts will mainly depend on the awareness and the level of adaptation in response to the changing climate. It is thus important to understand the role of the different factors that influence farmers' adaptation to ensure the development of appropriate policy measures and the design of successful development projects. This study examines farmers' perception of change in climatic attributes and the factors that influence farmers' choice of adaptation measures to climate change and variability. The estimated results from the climate change adaptation models indicate that level of education, age and wealth of the head of the household; access to credit and agricultural services; information on climate, and temperature all influence farmers' choices of adaptation. Moreover, lack of information on adaptation measures and lack of finance are seen as the main factors inhibiting adaptation to climate change. These conclusions were obtained with a Multinomial logit model, employing the results from a survey of 400 smallholder farmers in three districts in Tigray, northern Ethiopian. PMID:23728486

  10. Farm Level Adaptation to Climate Change: The Case of Farmer's in the Ethiopian Highlands

    NASA Astrophysics Data System (ADS)

    Gebrehiwot, Tagel; van der Veen, Anne

    2013-07-01

    In Ethiopia, climate change and associated risks are expected to have serious consequences for agriculture and food security. This in turn will seriously impact on the welfare of the people, particularly the rural farmers whose main livelihood depends on rain-fed agriculture. The level of impacts will mainly depend on the awareness and the level of adaptation in response to the changing climate. It is thus important to understand the role of the different factors that influence farmers' adaptation to ensure the development of appropriate policy measures and the design of successful development projects. This study examines farmers' perception of change in climatic attributes and the factors that influence farmers' choice of adaptation measures to climate change and variability. The estimated results from the climate change adaptation models indicate that level of education, age and wealth of the head of the household; access to credit and agricultural services; information on climate, and temperature all influence farmers' choices of adaptation. Moreover, lack of information on adaptation measures and lack of finance are seen as the main factors inhibiting adaptation to climate change. These conclusions were obtained with a Multinomial logit model, employing the results from a survey of 400 smallholder farmers in three districts in Tigray, northern Ethiopian.

  11. Quantum jumps in a two-level atom: Simple theories versus quantum trajectories

    NASA Astrophysics Data System (ADS)

    Wiseman, H. M.; Toombes, G. E.

    1999-09-01

    A strongly driven (Ω>>γ) two-level atom relaxes towards an equilibrium state ρ which is almost completely mixed. One interpretation of this state is that it represents an ensemble average, and that an individual atom is at any time in one of the eigenstates of ρ. The theory of Teich and Mahler [Phys. Rev. A 45, 3300 (1992)] makes this interpretation concrete, with an individual atom jumping stochastically between the two eigenstates when a photon is emitted. The dressed-atom theory is also supposed to describe the quantum jumps of an individual atom due to photoemissions. But the two pictures are contradictory because the dressed states of the atom are almost orthogonal to the eigenstates of ρ. In this paper we investigate three ways of measuring the field radiated by the atom, which attempt to reproduce the simple quantum jump dynamics of the dressed state or Teich and Mahler models. These are spectral detection (using optical filters), two-state jumps (using adaptive homodyne detection), and orthogonal jumps (another adaptive homodyne scheme). We find that the three schemes closely mimic the jumps of the dressed-state model, with errors of order 34(γ/Ω)2/3, 14(γ/Ω)2, and 34(γ/Ω)2, respectively. The significance of this result to the program of environmentally induced superselection is discussed.

  12. Incorporating diversity: meaning, levels of research, and implications for theory.

    PubMed

    Calasanti, T M

    1996-04-01

    Incorporating diverse experiences into gerontological theory, research, and practice is necessary for understanding the lives of all old people, and not only "special groups." I begin by explaining how incorporating diversity exposes the power relations constitutive of lived experiences. Using examples from retirement research, I demonstrate that starting with the voices of those with less power renders a more complete view of social reality. Further, a wider understanding of aging in the United States mandates that we move to the international-comparative level. This enables us to more closely scrutinize the often unquestioned structural and ideological processes that construct divergent aging experiences as well as to conceptualize alternatives. I conclude, then, by noting that a more inclusive approach forces us to see all aging experiences not as determined but rather as fluid, dialectical, contextual--and changeable through human actions. PMID:8920083

  13. Study on application of adaptive fuzzy control and neural network in the automatic leveling system

    NASA Astrophysics Data System (ADS)

    Xu, Xiping; Zhao, Zizhao; Lan, Weiyong; Sha, Lei; Qian, Cheng

    2015-04-01

    This paper discusses the adaptive fuzzy control and neural network BP algorithm in large flat automatic leveling control system application. The purpose is to develop a measurement system with a flat quick leveling, Make the installation on the leveling system of measurement with tablet, to be able to achieve a level in precision measurement work quickly, improve the efficiency of the precision measurement. This paper focuses on the automatic leveling system analysis based on fuzzy controller, Use of the method of combining fuzzy controller and BP neural network, using BP algorithm improve the experience rules .Construct an adaptive fuzzy control system. Meanwhile the learning rate of the BP algorithm has also been run-rate adjusted to accelerate convergence. The simulation results show that the proposed control method can effectively improve the leveling precision of automatic leveling system and shorten the time of leveling.

  14. Arbitrary-level hanging nodes for adaptive hphp-FEM approximations in 3D

    SciTech Connect

    Pavel Kus; Pavel Solin; David Andrs

    2014-11-01

    In this paper we discuss constrained approximation with arbitrary-level hanging nodes in adaptive higher-order finite element methods (hphp-FEM) for three-dimensional problems. This technique enables using highly irregular meshes, and it greatly simplifies the design of adaptive algorithms as it prevents refinements from propagating recursively through the finite element mesh. The technique makes it possible to design efficient adaptive algorithms for purely hexahedral meshes. We present a detailed mathematical description of the method and illustrate it with numerical examples.

  15. Next-Generation Force Fields from Symmetry-Adapted Perturbation Theory

    NASA Astrophysics Data System (ADS)

    McDaniel, Jesse G.; Schmidt, J. R.

    2016-05-01

    Symmetry-adapted perturbation theory (SAPT) provides a unique set of advantages for parameterizing next-generation force fields from first principles. SAPT provides a direct, basis-set superposition error free estimate of molecular interaction energies, a physically intuitive energy decomposition, and a seamless transition to an asymptotic picture of intermolecular interactions. These properties have been exploited throughout the literature to develop next-generation force fields for a variety of applications, including classical molecular dynamics simulations, crystal structure prediction, and quantum dynamics/spectroscopy. This review provides a brief overview of the formalism and theory of SAPT, along with a practical discussion of the various methodologies utilized to parameterize force fields from SAPT calculations. It also highlights a number of applications of SAPT-based force fields for chemical systems of particular interest. Finally, the review ends with a brief outlook on the future opportunities and challenges that remain for next-generation force fields based on SAPT.

  16. The polyvagal theory: New insights into adaptive reactions of the autonomic nervous system

    PubMed Central

    PORGES, STEPHEN W.

    2011-01-01

    The polyvagal theory describes an autonomic nervous system that is influenced by the central nervous system, sensitive to afferent influences, characterized by an adaptive reactivity dependent on the phylogeny of the neural circuits, and interactive with source nuclei in the brainstem regulating the striated muscles of the face and head. The theory is dependent on accumulated knowledge describing the phylogenetic transitions in the vertebrate autonomic nervous system. Its specific focus is on the phylogenetic shift between reptiles and mammals that resulted in specific changes to the vagal pathways regulating the heart. As the source nuclei of the primary vagal efferent pathways regulating the heart shifted from the dorsal motor nucleus of the vagus in reptiles to the nucleus ambiguus in mammals, a face–heart connection evolved with emergent properties of a social engagement system that would enable social interactions to regulate visceral state. PMID:19376991

  17. The polyvagal theory: new insights into adaptive reactions of the autonomic nervous system.

    PubMed

    Porges, Stephen W

    2009-04-01

    The polyvagal theory describes an autonomic nervous system that is influenced by the central nervous system, sensitive to afferent influences, characterized by an adaptive reactivity dependent on the phylogeny of the neural circuits, and interactive with source nuclei in the brainstem regulating the striated muscles of the face and head. The theory is dependent on accumulated knowledge describing the phylogenetic transitions in the vertebrate autonomic nervous system. Its specific focus is on the phylogenetic shift between reptiles and mammals that resulted in specific changes to the vagal pathways regulating the heart. As the source nuclei of the primary vagal efferent pathways regulating the heart shifted from the dorsal motor nucleus of the vagus in reptiles to the nucleus ambiguus in mammals, a face-heart connection evolved with emergent properties of a social engagement system that would enable social interactions to regulate visceral state. PMID:19376991

  18. Next-Generation Force Fields from Symmetry-Adapted Perturbation Theory.

    PubMed

    McDaniel, Jesse G; Schmidt, J R

    2016-05-27

    Symmetry-adapted perturbation theory (SAPT) provides a unique set of advantages for parameterizing next-generation force fields from first principles. SAPT provides a direct, basis-set superposition error free estimate of molecular interaction energies, a physically intuitive energy decomposition, and a seamless transition to an asymptotic picture of intermolecular interactions. These properties have been exploited throughout the literature to develop next-generation force fields for a variety of applications, including classical molecular dynamics simulations, crystal structure prediction, and quantum dynamics/spectroscopy. This review provides a brief overview of the formalism and theory of SAPT, along with a practical discussion of the various methodologies utilized to parameterize force fields from SAPT calculations. It also highlights a number of applications of SAPT-based force fields for chemical systems of particular interest. Finally, the review ends with a brief outlook on the future opportunities and challenges that remain for next-generation force fields based on SAPT. PMID:27070322

  19. Intermolecular symmetry-adapted perturbation theory study of large organic complexes

    SciTech Connect

    Heßelmann, Andreas; Korona, Tatiana

    2014-09-07

    Binding energies for the complexes of the S12L database by Grimme [Chem. Eur. J. 18, 9955 (2012)] were calculated using intermolecular symmetry-adapted perturbation theory combined with a density-functional theory description of the interacting molecules. The individual interaction energy decompositions revealed no particular change in the stabilisation pattern as compared to smaller dimer systems at equilibrium structures. This demonstrates that, to some extent, the qualitative description of the interaction of small dimer systems may be extrapolated to larger systems, a method that is widely used in force-fields in which the total interaction energy is decomposed into atom-atom contributions. A comparison of the binding energies with accurate experimental reference values from Grimme, the latter including thermodynamic corrections from semiempirical calculations, has shown a fairly good agreement to within the error range of the reference binding energies.

  20. High-speed train control based on multiple-model adaptive control with second-level adaptation

    NASA Astrophysics Data System (ADS)

    Zhou, Yonghua; Zhang, Zhenlin

    2014-05-01

    Speed uplift has become the leading trend for the development of current railway traffic. Ideally, under the high-speed transportation infrastructure, trains run at specified positions with designated speeds at appointed times. In view of the faster adaptation ability of multiple-model adaptive control with second-level adaptation (MMAC-SLA), we propose one type of MMAC-SLA for a class of nonlinear systems such as cascaded vehicles. By using an input decomposition technique, the corresponding stability proof is solved for the proposed MMAC-SLA, which synthesises the control signals from the weighted multiple models. The control strategy is utilised to challenge the position and speed tracking of high-speed trains with uncertain parameters. The simulation results demonstrate that the proposed MMAC-SLA can achieve small tracking errors with moderate in-train forces incurred under the control of flattening input signals with practical enforceability. This study also provides a new idea for the control of in-train forces by tracking the positions and speeds of cars while considering power constraints.

  1. Rational adaptation under task and processing constraints: implications for testing theories of cognition and action.

    PubMed

    Howes, Andrew; Lewis, Richard L; Vera, Alonso

    2009-10-01

    The authors assume that individuals adapt rationally to a utility function given constraints imposed by their cognitive architecture and the local task environment. This assumption underlies a new approach to modeling and understanding cognition-cognitively bounded rational analysis-that sharpens the predictive acuity of general, integrated theories of cognition and action. Such theories provide the necessary computational means to explain the flexible nature of human behavior but in doing so introduce extreme degrees of freedom in accounting for data. The new approach narrows the space of predicted behaviors through analysis of the payoff achieved by alternative strategies, rather than through fitting strategies and theoretical parameters to data. It extends and complements established approaches, including computational cognitive architectures, rational analysis, optimal motor control, bounded rationality, and signal detection theory. The authors illustrate the approach with a reanalysis of an existing account of psychological refractory period (PRP) dual-task performance and the development and analysis of a new theory of ordered dual-task responses. These analyses yield several novel results, including a new understanding of the role of strategic variation in existing accounts of PRP and the first predictive, quantitative account showing how the details of ordered dual-task phenomena emerge from the rational control of a cognitive system subject to the combined constraints of internal variance, motor interference, and a response selection bottleneck. PMID:19839682

  2. Teaching Theory at the Master's Level: Report of a National Survey of Theory Instructors.

    ERIC Educational Resources Information Center

    McEwen, Melanie

    2000-01-01

    Nursing theory instructors (n=44) displayed a general consensus on essential course content. They expressed a need for more emphasis on middle-range and practice theories rather than grand narratives and the research-practice-theory relationship. (SK)

  3. Adaptive time stepping algorithm for Lagrangian transport models: Theory and idealised test cases

    NASA Astrophysics Data System (ADS)

    Shah, Syed Hyder Ali Muttaqi; Heemink, Arnold Willem; Gräwe, Ulf; Deleersnijder, Eric

    2013-08-01

    Random walk simulations have an excellent potential in marine and oceanic modelling. This is essentially due to their relative simplicity and their ability to represent advective transport without being plagued by the deficiencies of the Eulerian methods. The physical and mathematical foundations of random walk modelling of turbulent diffusion have become solid over the years. Random walk models rest on the theory of stochastic differential equations. Unfortunately, the latter and the related numerical aspects have not attracted much attention in the oceanic modelling community. The main goal of this paper is to help bridge the gap by developing an efficient adaptive time stepping algorithm for random walk models. Its performance is examined on two idealised test cases of turbulent dispersion; (i) pycnocline crossing and (ii) non-flat isopycnal diffusion, which are inspired by shallow-sea dynamics and large-scale ocean transport processes, respectively. The numerical results of the adaptive time stepping algorithm are compared with the fixed-time increment Milstein scheme, showing that the adaptive time stepping algorithm for Lagrangian random walk models is more efficient than its fixed step-size counterpart without any loss in accuracy.

  4. Adaptive Disturbance Tracking Theory with State Estimation and State Feedback for Region II Control of Large Wind Turbines

    NASA Technical Reports Server (NTRS)

    Balas, Mark J.; Thapa Magar, Kaman S.; Frost, Susan A.

    2013-01-01

    A theory called Adaptive Disturbance Tracking Control (ADTC) is introduced and used to track the Tip Speed Ratio (TSR) of 5 MW Horizontal Axis Wind Turbine (HAWT). Since ADTC theory requires wind speed information, a wind disturbance generator model is combined with lower order plant model to estimate the wind speed as well as partial states of the wind turbine. In this paper, we present a proof of stability and convergence of ADTC theory with lower order estimator and show that the state feedback can be adaptive.

  5. Self-adaptive phosphor coating technology for wafer-level scale chip packaging

    NASA Astrophysics Data System (ADS)

    Linsong, Zhou; Haibo, Rao; Wei, Wang; Xianlong, Wan; Junyuan, Liao; Xuemei, Wang; Da, Zhou; Qiaolin, Lei

    2013-05-01

    A new self-adaptive phosphor coating technology has been successfully developed, which adopted a slurry method combined with a self-exposure process. A phosphor suspension in the water-soluble photoresist was applied and exposed to LED blue light itself and developed to form a conformal phosphor coating with self-adaptability to the angular distribution of intensity of blue light and better-performing spatial color uniformity. The self-adaptive phosphor coating technology had been successfully adopted in the wafer surface to realize a wafer-level scale phosphor conformal coating. The first-stage experiments show satisfying results and give an adequate demonstration of the flexibility of self-adaptive coating technology on application of WLSCP.

  6. Future planning and evaluation for automated adaptive minehunting: a roadmap for mine countermeasures theory modernization

    NASA Astrophysics Data System (ADS)

    Garcia, Gregory A.; Wettergren, Thomas A.

    2012-06-01

    This paper presents a discussion of U.S. naval mine countermeasures (MCM) theory modernization in light of advances in the areas of autonomy, tactics, and sensor processing. The unifying theme spanning these research areas concerns the capability for in situ adaptation of processing algorithms, plans, and vehicle behaviors enabled through run-time situation assessment and performance estimation. Independently, each of these technology developments impact the MCM Measures of Effectiveness1 [MOE(s)] of time and risk by improving one or more associated Measures of Performance2 [MOP(s)]; the contribution of this paper is to outline an integrated strategy for realizing the cumulative benefits of these technology enablers to the United States Navy's minehunting capability. An introduction to the MCM problem is provided to frame the importance of the foundational research and the ramifications of the proposed strategy on the MIW community. We then include an overview of current and future adaptive capability research in the aforementioned areas, highlighting a departure from the existing rigid assumption-based approaches while identifying anticipated technology acceptance issues. Consequently, the paper describes an incremental strategy for transitioning from the current minehunting paradigm where tactical decision aids rely on a priori intelligence and there is little to no in situ adaptation or feedback to a future vision where unmanned systems3, equipped with a representation of the commander's intent, are afforded the authority and ability to adapt to environmental perturbations with minimal human-in-the-loop supervision. The discussion concludes with an articulation of the science and technology issues which the MCM research community must continue to address.

  7. The Colorado Climate Preparedness Project: A Systematic Approach to Assessing Efforts Supporting State-Level Adaptation

    NASA Astrophysics Data System (ADS)

    Klein, R.; Gordon, E.

    2010-12-01

    Scholars and policy analysts often contend that an effective climate adaptation strategy must entail "mainstreaming," or incorporating responses to possible climate impacts into existing planning and management decision frameworks. Such an approach, however, makes it difficult to assess the degree to which decisionmaking entities are engaging in adaptive activities that may or may not be explicitly framed around a changing climate. For example, a drought management plan may not explicitly address climate change, but the activities and strategies outlined in it may reduce vulnerabilities posed by a variable and changing climate. Consequently, to generate a strategic climate adaptation plan requires identifying the entire suite of activities that are implicitly linked to climate and may affect adaptive capacity within the system. Here we outline a novel, two-pronged approach, leveraging social science methods, to understanding adaptation throughout state government in Colorado. First, we conducted a series of interviews with key actors in state and federal government agencies, non-governmental organizations, universities, and other entities engaged in state issues. The purpose of these interviews was to elicit information about current activities that may affect the state’s adaptive capacity and to identify future climate-related needs across the state. Second, we have developed an interactive database cataloging organizations, products, projects, and people actively engaged in adaptive planning and policymaking that are relevant to the state of Colorado. The database includes a wiki interface, helping create a dynamic component that will enable frequent updating as climate-relevant information emerges. The results of this project are intended to paint a clear picture of sectors and agencies with higher and lower levels of adaptation awareness and to provide a roadmap for the next gubernatorial administration to pursue a more sophisticated climate adaptation agenda

  8. Climate change vulnerability, adaptation and risk perceptions at farm level in Punjab, Pakistan.

    PubMed

    Abid, Muhammad; Schilling, Janpeter; Scheffran, Jürgen; Zulfiqar, Farhad

    2016-03-15

    Pakistan is among the countries highly exposed and vulnerable to climate change. The country has experienced many severe floods, droughts and storms over the last decades. However, little research has focused on the investigation of vulnerability and adaptation to climate-related risks in Pakistan. Against this backdrop, this article investigates the farm level risk perceptions and different aspects of vulnerability to climate change including sensitivity and adaptive capacity at farm level in Pakistan. We interviewed a total of 450 farming households through structured questionnaires in three districts of Punjab province of Pakistan. This study identified a number of climate-related risks perceived by farm households such as extreme temperature events, insect attacks, animal diseases and crop pests. Limited water availability, high levels of poverty and a weak role of local government in providing proper infrastructure were the factors that make farmers more sensitive to climate-related risks. Uncertainty or reduction in crop and livestock yields; changed cropping calendars and water shortage were the major adverse impacts of climate-related risks reported by farmers in the study districts. Better crop production was reported as the only positive effect. Further, this study identified a number of farm level adaptation methods employed by farm households that include changes in crop variety, crop types, planting dates and input mix, depending upon the nature of the climate-related risks. Lack of resources, limited information, lack of finances and institutional support were some constraints that limit the adaptive capacity of farm households. This study also reveals a positive role of cooperation and negative role of conflict in the adaptation process. The study suggests to address the constraints to adaptation and to improve farm level cooperation through extended outreach and distribution of institutional services, particularly climate-specific farm advisory

  9. A Theory-Based Approach to Restructuring Middle Level Schools.

    ERIC Educational Resources Information Center

    Midgley, Carol; Maehr, Martin L.

    This paper describes the implementation of a reform program in a middle school located in a relatively large school district in southeastern Michigan. First, an integrative theory is presented as a promising framework for reforming middle-grade schools. The theory was developed within a social-cognitive framework that emphasizes the importance of…

  10. Adaptive Force Control in Grasping as a Function of Level of Developmental Disability

    ERIC Educational Resources Information Center

    Sprague, R. L.; Deutsch, K. M.; Newell, K. M.

    2009-01-01

    Background: The adaptation to the task demands of grasping (grip mode and object mass) was investigated as a function of level of developmental disability. Methods: Subjects grasped objects of different grip widths and masses that were instrumented to record grip forces. Results: Proportionally, fewer participants from the profound compared with…

  11. Cities and Sea Level Rise: A Roadmap for Flood Hazard Adaptation

    NASA Astrophysics Data System (ADS)

    Horn, Diane; Cousins, Ann

    2016-04-01

    Coastal cities will face a range of increasingly severe challenges as sea level rises, and adaptation to future flood risk will require more than structural defences. Many cities will not be able to rely solely on engineering structures for protection and will need to develop a suite of policy responses to increase their resilience to impacts of rising sea level. The tools to promote flood risk adaptation are already within the capacity of most cities, with an assortment of policy tools available to address other land-use problems which can be refashioned and used to adapt to sea level rise. This study reviews approaches for urban adaptation through detailed analyses of case studies of cities which have developed flood adaptation strategies that combine structural defences with innovative approaches to living with flood risk. The aim of the overall project is to produce a 'roadmap' to guide practitioners through the process of analysing coastal flood risk in urban areas. Methodologies and tools to estimate vulnerability to coastal flooding, damages suffered, and the assessment of flood defences and adaptation measures are complemented with a discussion on the essential impact that local policy has on the treatment of coastal flooding and the constraints and opportunities that result from the specific country or locality characteristics in relation to economic, political, social and environmental priorities, which are likely to dictate the approach to coastal flooding and the actions proposed. Case studies of adaptation strategies used by Rotterdam, Bristol, Ho Chi Minh City and Norfolk, Virginia, are used to draw out a range of good practice elements that promote effective adaptation to sea level rise. These can be grouped into risk reduction, governance issues, and insurance, and can be used to provide examples of how other cities could adopt and implement flood adaptation strategies from a relatively limited starting position. Most cities will neither be able to

  12. Peculiarities of transformation of adaptation level of the astronaut in conditions of long-lasting flight

    NASA Astrophysics Data System (ADS)

    Padashulya, H.; Prisnyakova, L.; Prisnyakov, V.

    Prognostication of the development of adverse factors of psychological processes in the personality of the astronaut who time and again feels transformation of internal structure of his personality is one of cardinal problems of the long-lasting flight Adaptation to changing conditions of long-lasting flight is of particular importance because it has an effect on the efficiency of discharged functions and mutual relations in the team The fact of standard psychological changes emerging in the personality being in the state of structural transformations is the precondition for the possibility of prognostication Age-specific gender and temperamental differences in the personality enable to standardize these changes Examination of the process of transformation of adaptation level of the personality in the varied environment depending on the type of temperament and constituents age and gender is chief object of the report In the report it is shown that in the process of transformation of adaptation parameters - attitude to guillemotleft work guillemotright guillemotleft family guillemotright guillemotleft environment guillemotright and guillemotleft ego guillemotright - the changes can go in two directions - in the direction of increase and decline of indexes The trend of increase enables to accumulate them and form potentiality to reduce or increase the level of personality adaptation There is a hypothesis that the dynamics of the process of transformation of adaptation parameter is shown up in the orientation of increase of

  13. Understanding Students' Adaptation to Graduate School: An Integration of Social Support Theory and Social Learning Theory

    ERIC Educational Resources Information Center

    Tsay, Crystal Han-Huei

    2012-01-01

    The contemporary business world demands adaptive individuals (Friedman & Wyman, 2005). Adaptation is essential for any life transition. It often involves developing coping mechanisms, strategies, and seeking of social support. Adaptation occurs in many settings from moving to a new culture, taking a new job, starting or finishing an…

  14. Tree-level unitarity and renormalizability in Lifshitz scalar theory

    NASA Astrophysics Data System (ADS)

    Fujimori, Toshiaki; Inami, Takeo; Izumi, Keisuke; Kitamura, Tomotaka

    2016-01-01

    We study unitarity and renormalizability in the Lifshitz scalar field theory, which is characterized by an anisotropic scaling between the space and time directions. Without the Lorentz symmetry, both the unitarity and the renormalizability conditions are modified from those in relativistic theories. We show that for renormalizability, an extended version of the power-counting condition is required in addition to the conventional one. The unitarity bound for S-matrix elements also gives stronger constraints on interaction terms because of the reference frame dependence of scattering amplitudes. We prove that both unitarity and renormalizability require identical conditions as in the case of conventional relativistic theories.

  15. Intramolecular symmetry-adapted perturbation theory with a single-determinant wavefunction

    NASA Astrophysics Data System (ADS)

    Pastorczak, Ewa; Prlj, Antonio; Gonthier, Jérôme F.; Corminboeuf, Clémence

    2015-12-01

    We introduce an intramolecular energy decomposition scheme for analyzing non-covalent interactions within molecules in the spirit of symmetry-adapted perturbation theory (SAPT). The proposed intra-SAPT approach is based upon the Chemical Hamiltonian of Mayer [Int. J. Quantum Chem. 23(2), 341-363 (1983)] and the recently introduced zeroth-order wavefunction [J. F. Gonthier and C. Corminboeuf, J. Chem. Phys. 140(15), 154107 (2014)]. The scheme decomposes the interaction energy between weakly bound fragments located within the same molecule into physically meaningful components, i.e., electrostatic-exchange, induction, and dispersion. Here, we discuss the key steps of the approach and demonstrate that a single-determinant wavefunction can already deliver a detailed and insightful description of a wide range of intramolecular non-covalent phenomena such as hydrogen bonds, dihydrogen contacts, and π - π stacking interactions. Intra-SAPT is also used to shed the light on competing intra- and intermolecular interactions.

  16. Intramolecular symmetry-adapted perturbation theory with a single-determinant wavefunction

    SciTech Connect

    Pastorczak, Ewa; Prlj, Antonio; Corminboeuf, Clémence; Gonthier, Jérôme F.

    2015-12-14

    We introduce an intramolecular energy decomposition scheme for analyzing non-covalent interactions within molecules in the spirit of symmetry-adapted perturbation theory (SAPT). The proposed intra-SAPT approach is based upon the Chemical Hamiltonian of Mayer [Int. J. Quantum Chem. 23(2), 341–363 (1983)] and the recently introduced zeroth-order wavefunction [J. F. Gonthier and C. Corminboeuf, J. Chem. Phys. 140(15), 154107 (2014)]. The scheme decomposes the interaction energy between weakly bound fragments located within the same molecule into physically meaningful components, i.e., electrostatic-exchange, induction, and dispersion. Here, we discuss the key steps of the approach and demonstrate that a single-determinant wavefunction can already deliver a detailed and insightful description of a wide range of intramolecular non-covalent phenomena such as hydrogen bonds, dihydrogen contacts, and π − π stacking interactions. Intra-SAPT is also used to shed the light on competing intra- and intermolecular interactions.

  17. Hand movements classification for myoelectric control system using adaptive resonance theory.

    PubMed

    Jahani Fariman, H; Ahmad, Siti A; Hamiruce Marhaban, M; Alijan Ghasab, M; Chappell, Paul H

    2016-03-01

    This research proposes an exploratory study of a simple, accurate, and computationally efficient movement classification technique for prosthetic hand application. Surface myoelectric signals were acquired from the four muscles, namely, flexor carpi ulnaris, extensor carpi radialis, biceps brachii, and triceps brachii, of four normal-limb subjects. The signals were segmented, and the features were extracted with a new combined time-domain feature extraction method. Fuzzy C-means clustering method and scatter plot were used to evaluate the performance of the proposed multi-feature versus Hudgins' multi-feature. The movements were classified with a hybrid Adaptive Resonance Theory-based neural network. Comparative results indicate that the proposed hybrid classifier not only has good classification accuracy (89.09%) but also a significantly improved computation time. PMID:26581764

  18. REVIEW: An overview of adaptive model theory: solving the problems of redundancy, resources, and nonlinear interactions in human movement control

    NASA Astrophysics Data System (ADS)

    Neilson, Peter D.; Neilson, Megan D.

    2005-09-01

    Adaptive model theory (AMT) is a computational theory that addresses the difficult control problem posed by the musculoskeletal system in interaction with the environment. It proposes that the nervous system creates motor maps and task-dependent synergies to solve the problems of redundancy and limited central resources. These lead to the adaptive formation of task-dependent feedback/feedforward controllers able to generate stable, noninteractive control and render nonlinear interactions unobservable in sensory-motor relationships. AMT offers a unified account of how the nervous system might achieve these solutions by forming internal models. This is presented as the design of a simulator consisting of neural adaptive filters based on cerebellar circuitry. It incorporates a new network module that adaptively models (in real time) nonlinear relationships between inputs with changing and uncertain spectral and amplitude probability density functions as is the case for sensory and motor signals.

  19. Cognitive Adaptation Theory as a Predictor of Adjustment to Emerging Adulthood for Youth with and without Type 1 Diabetes

    PubMed Central

    Helgeson, Vicki S.; Reynolds, Kerry A.; Siminerio, Linda M.; Becker, Dorothy J.; Escobar, Oscar

    2014-01-01

    Objective: The purpose of the study was to determine whether resilience, defined by cognitive adaptation theory, predicted emerging adulthood outcomes among youth with and without type 1 diabetes. Methods: Youth with (n = 118) and without type 1 diabetes (n = 122), who were part of a previous longitudinal study during adolescence, completed on-line questionnaires during their senior year of high school and one and two years later. They were average age 18, 53% female, and 93% white. Questionnaires assessed cognitive adaptation theory (CAT) indicators (self-esteem, mastery, optimism) and psychological, relationship, behavioral, vocational, and, for those with diabetes, diabetes outcomes. Results: The CAT index at baseline predicted reduced psychological distress, enhanced psychological well-being, increased friend support, reduced friend conflict, the presence of romantic relationships, reduced likelihood of romantic breakups, higher GPA, higher work satisfaction, and lower work stress during the transition to emerging adulthood. Among those with diabetes, the CAT index predicted better self-care behavior and revealed a marginal relation to better glycemic control. Analyses controlled for baseline levels when appropriate. Findings were stronger one year than two years post high school graduation, and findings were stronger for those with than without diabetes. Youth with diabetes also scored lower on the CAT index than youth without diabetes. Conclusions: These findings suggest that the implications of CAT include not only psychological health but also relationship, vocational, and diabetes outcomes. Those who score lower on CAT indicators should be identified as children so that interventions designed to enhance resilience can be implemented. PMID:25294781

  20. Cities and Sea Level Rise: A Roadmap for Flood Hazard Adaptation

    NASA Astrophysics Data System (ADS)

    Horn, D. P.; Cousins, A.

    2015-12-01

    Coastal cities will face a range of increasingly severe challenges as sea level rises, and adaptation to future flood risk will require more than structural defences. Many cities will not be able to rely solely on engineering structures for protection and will need to develop a suite of policy responses to increase their resilience to impacts of rising sea level. Local governments generally maintain day-to-day responsibility and control over the use of the vast majority of property at risk of flooding, and the tools to promote flood risk adaptation are already within the capacity of most cities. Policy tools available to address other land-use problems can be refashioned and used to adapt to sea level rise. This study reviews approaches for urban adaptation through case studies of cities which have developed flood adaptation strategies that combine structural defences with innovative approaches to living with flood risk. The aim of the overall project is to produce a 'roadmap' to guide practitioners through the process of analysing coastal flood risk in urban areas. Technical knowledge of flood risk reduction measures is complemented with a consideration of the essential impact that local policy has on the treatment of coastal flooding and the constraints and opportunities that result from the specific country or locality characteristics in relation to economic, political, social and environmental priorities, which are likely to dictate the approach to coastal flooding and the actions proposed. Detailed analyses of the adaptation strategies used by Rotterdam (Netherlands), Bristol (UK), and Norfolk (Virginia) are used to draw out a range of good practice elements that promote effective adaptation to sea level rise. These can be grouped into risk reduction, governance issues, and insurance, and can be used to provide examples of how other cities could adopt and implement flood adaptation strategies from a relatively limited starting position. Most cities will

  1. Multi-Level Adaptive Techniques (MLAT) for singular-perturbation problems

    NASA Technical Reports Server (NTRS)

    Brandt, A.

    1978-01-01

    The multilevel (multigrid) adaptive technique, a general strategy of solving continuous problems by cycling between coarser and finer levels of discretization is described. It provides very fast general solvers, together with adaptive, nearly optimal discretization schemes. In the process, boundary layers are automatically either resolved or skipped, depending on a control function which expresses the computational goal. The global error decreases exponentially as a function of the overall computational work, in a uniform rate independent of the magnitude of the singular-perturbation terms. The key is high-order uniformly stable difference equations, and uniformly smoothing relaxation schemes.

  2. Implementation of a mesh adaptive scheme based on an element-level error indicator

    NASA Technical Reports Server (NTRS)

    Keating, Scott; Felippa, Carlos A.; Militello, Carmelo

    1993-01-01

    We investigate the formulation and application of element-level error indicators based on parametrized variational principles. The qualifier 'element-level' means that no information from adjacent elements is used for error estimation. This property is ideally suited to drive adaptive mesh refinement on parallel computers where access to neighboring elements resident on different processors may incur significant computational overhead. Furthermore, such indicators are not affected by physical jumps at junctures or interfaces. An element-level indicator has been derived from the higher-order element energy and applied to r and h mesh adaptation of meshes in plates and shell structures. We report on our initial experiments with a cylindrical shell that intersects with fist plates forming a simplified 'wing-body intersection' benchmark problem.

  3. A new adaptive exponential smoothing method for non-stationary time series with level shifts

    NASA Astrophysics Data System (ADS)

    Monfared, Mohammad Ali Saniee; Ghandali, Razieh; Esmaeili, Maryam

    2014-07-01

    Simple exponential smoothing (SES) methods are the most commonly used methods in forecasting and time series analysis. However, they are generally insensitive to non-stationary structural events such as level shifts, ramp shifts, and spikes or impulses. Similar to that of outliers in stationary time series, these non-stationary events will lead to increased level of errors in the forecasting process. This paper generalizes the SES method into a new adaptive method called revised simple exponential smoothing (RSES), as an alternative method to recognize non-stationary level shifts in the time series. We show that the new method improves the accuracy of the forecasting process. This is done by controlling the number of observations and the smoothing parameter in an adaptive approach, and in accordance with the laws of statistical control limits and the Bayes rule of conditioning. We use a numerical example to show how the new RSES method outperforms its traditional counterpart, SES.

  4. A GPU-accelerated adaptive discontinuous Galerkin method for level set equation

    NASA Astrophysics Data System (ADS)

    Karakus, A.; Warburton, T.; Aksel, M. H.; Sert, C.

    2016-01-01

    This paper presents a GPU-accelerated nodal discontinuous Galerkin method for the solution of two- and three-dimensional level set (LS) equation on unstructured adaptive meshes. Using adaptive mesh refinement, computations are localised mostly near the interface location to reduce the computational cost. Small global time step size resulting from the local adaptivity is avoided by local time-stepping based on a multi-rate Adams-Bashforth scheme. Platform independence of the solver is achieved with an extensible multi-threading programming API that allows runtime selection of different computing devices (GPU and CPU) and different threading interfaces (CUDA, OpenCL and OpenMP). Overall, a highly scalable, accurate and mass conservative numerical scheme that preserves the simplicity of LS formulation is obtained. Efficiency, performance and local high-order accuracy of the method are demonstrated through distinct numerical test cases.

  5. Adapting evidence-based interventions using a common theory, practices, and principles.

    PubMed

    Rotheram-Borus, Mary Jane; Swendeman, Dallas; Becker, Kimberly D

    2014-01-01

    Hundreds of validated evidence-based intervention programs (EBIP) aim to improve families' well-being; however, most are not broadly adopted. As an alternative diffusion strategy, we created wellness centers to reach families' everyday lives with a prevention framework. At two wellness centers, one in a middle-class neighborhood and one in a low-income neighborhood, popular local activity leaders (instructors of martial arts, yoga, sports, music, dancing, Zumba), and motivated parents were trained to be Family Mentors. Trainings focused on a framework that taught synthesized, foundational prevention science theory, practice elements, and principles, applied to specific content areas (parenting, social skills, and obesity). Family Mentors were then allowed to adapt scripts and activities based on their cultural experiences but were closely monitored and supervised over time. The framework was implemented in a range of activities (summer camps, coaching) aimed at improving social, emotional, and behavioral outcomes. Successes and challenges are discussed for (a) engaging parents and communities; (b) identifying and training Family Mentors to promote children and families' well-being; and (c) gathering data for supervision, outcome evaluation, and continuous quality improvement. To broadly diffuse prevention to families, far more experimentation is needed with alternative and engaging implementation strategies that are enhanced with knowledge harvested from researchers' past 30 years of experience creating EBIP. One strategy is to train local parents and popular activity leaders in applying robust prevention science theory, common practice elements, and principles of EBIP. More systematic evaluation of such innovations is needed. PMID:24079747

  6. The Theory of Adaptive Dispersion and Acoustic-phonetic Properties of Cross-language Lexical-tone Systems

    NASA Astrophysics Data System (ADS)

    Alexander, Jennifer Alexandra

    Lexical-tone languages use fundamental frequency (F0/pitch) to convey word meaning. About 41.8% of the world's languages use lexical tone (Maddieson, 2008), yet those systems are under-studied. I aim to increase our understanding of speech-sound inventory organization by extending to tone-systems a model of vowel-system organization, the Theory of Adaptive Dispersion (TAD) (Liljencrants and Lindblom, 1972). This is a cross-language investigation of whether and how the size of a tonal inventory affects (A) acoustic tone-space size and (B) dispersion of tone categories within the tone-space. I compared five languages with very different tone inventories: Cantonese (3 contour, 3 level tones); Mandarin (3 contour, 1 level tone); Thai (2 contour, 3 level tones); Yoruba (3 level tones only); and Igbo (2 level tones only). Six native speakers (3 female) of each language produced 18 CV syllables in isolation, with each of his/her language's tones, six times. I measured tonal F0 across the vowel at onset, midpoint, and offglide. Tone-space size was the F0 difference in semitones (ST) between each language's highest and lowest tones. Tone dispersion was the F0 distance (ST) between two tones shared by multiple languages. Following the TAD, I predicted that languages with larger tone inventories would have larger tone-spaces. Against expectations, tone-space size was fixed across level-tone languages at midpoint and offglide, and across contour-tone languages (except Thai) at offglide. However, within each language type (level-tone vs. contour-tone), languages with smaller tone inventories had larger tone spaces at onset. Tone-dispersion results were also unexpected. The Cantonese mid-level tone was further dispersed from a tonal baseline than the Yoruba mid-level tone; Cantonese mid-level tone dispersion was therefore greater than theoretically necessary. The Cantonese high-level tone was also further dispersed from baseline than the Mandarin high-level tone -- at midpoint

  7. Adaptive nonlocal means filtering based on local noise level for CT denoising

    SciTech Connect

    Li, Zhoubo; Trzasko, Joshua D.; Lake, David S.; Blezek, Daniel J.; Manduca, Armando; Yu, Lifeng; Fletcher, Joel G.; McCollough, Cynthia H.

    2014-01-15

    Purpose: To develop and evaluate an image-domain noise reduction method based on a modified nonlocal means (NLM) algorithm that is adaptive to local noise level of CT images and to implement this method in a time frame consistent with clinical workflow. Methods: A computationally efficient technique for local noise estimation directly from CT images was developed. A forward projection, based on a 2D fan-beam approximation, was used to generate the projection data, with a noise model incorporating the effects of the bowtie filter and automatic exposure control. The noise propagation from projection data to images was analytically derived. The analytical noise map was validated using repeated scans of a phantom. A 3D NLM denoising algorithm was modified to adapt its denoising strength locally based on this noise map. The performance of this adaptive NLM filter was evaluated in phantom studies in terms of in-plane and cross-plane high-contrast spatial resolution, noise power spectrum (NPS), subjective low-contrast spatial resolution using the American College of Radiology (ACR) accreditation phantom, and objective low-contrast spatial resolution using a channelized Hotelling model observer (CHO). Graphical processing units (GPU) implementation of this noise map calculation and the adaptive NLM filtering were developed to meet demands of clinical workflow. Adaptive NLM was piloted on lower dose scans in clinical practice. Results: The local noise level estimation matches the noise distribution determined from multiple repetitive scans of a phantom, demonstrated by small variations in the ratio map between the analytical noise map and the one calculated from repeated scans. The phantom studies demonstrated that the adaptive NLM filter can reduce noise substantially without degrading the high-contrast spatial resolution, as illustrated by modulation transfer function and slice sensitivity profile results. The NPS results show that adaptive NLM denoising preserves the

  8. Adapting high-level language programs for parallel processing using data flow

    NASA Technical Reports Server (NTRS)

    Standley, Hilda M.

    1988-01-01

    EASY-FLOW, a very high-level data flow language, is introduced for the purpose of adapting programs written in a conventional high-level language to a parallel environment. The level of parallelism provided is of the large-grained variety in which parallel activities take place between subprograms or processes. A program written in EASY-FLOW is a set of subprogram calls as units, structured by iteration, branching, and distribution constructs. A data flow graph may be deduced from an EASY-FLOW program.

  9. Serum testosterone levels and excessive erythrocytosis during the process of adaptation to high altitudes

    PubMed Central

    Gonzales, Gustavo F

    2013-01-01

    Populations living at high altitudes (HAs), particularly in the Peruvian Andes, are characterized by a mixture of subjects with erythrocytosis (16 g dl−121 g dl−1). Elevated haemoglobin values (EE) are associated with chronic mountain sickness, a condition reflecting the lack of adaptation to HA. According to current data, native men from regions of HA are not adequately adapted to live at such altitudes if they have elevated serum testosterone levels. This seems to be due to an increased conversion of dehydroepiandrosterone sulphate (DHEAS) to testosterone. Men with erythrocytosis at HAs show higher serum androstenedione levels and a lower testosterone/androstenedione ratio than men with EE, suggesting reduced 17beta-hydroxysteroid dehydrogenase (17beta-HSD) activity. Lower 17beta-HSD activity via Δ4-steroid production in men with erythrocytosis at HA may protect against elevated serum testosterone levels, thus preventing EE. The higher conversion of DHEAS to testosterone in subjects with EE indicates increased 17beta-HSD activity via the Δ5-pathway. Currently, there are various situations in which people live (human biodiversity) with low or high haemoglobin levels at HA. Antiquity could be an important adaptation component for life at HA, and testosterone seems to participate in this process. PMID:23524530

  10. Sea-level rise risks to coastal cities: what are the limits to adaptation?

    NASA Astrophysics Data System (ADS)

    Nicholls, R. J.; Reeder, T.; Brown, S.; Haigh, I. D.

    2015-12-01

    Understanding the consequence of sea-level rise for coastal cities has long lead times and huge political implications. Civilisation has emerged and developed during a period of several thousand years during which in geological terms sea level has been unusually stable. We have now moved out of this period raising important challenges for the future. In 2005 there were 136 coastal cities with a population exceeding one million people and a collective population of 400 million people. All these cities are threatened by flooding from the sea to varying degrees and these risks are increasing due to growing exposure (people and assets), rising sea levels due to climate change, and in some cities, significant coastal subsidence due to human agency (drainage and groundwater withdrawals from susceptible soils). City abandonment due to sea-level rise is widely discussed in the media, but most of the discussion is speculative. The limits to adaptation and abandonment of cities are not predictable in a formal sense - while the rise in mean sea level raises the likelihood of a catastrophic flood, extreme events are what cause damage and trigger a response, be it abandonment or a defence upgrade. Several types of potential adaptation limits can be recognised: (1) physical/engineering limits; (2) economic/financial limits; and (3) socio-political limits. The latter two types of limits are much less understood, and yet issues such as loss of confidence rather than a simple engineering failure may be instrumental in the future of a coastal city. There are few studies which quantify the sea-level rise threshold at which cities will be challenged, especially for large rises exceeding a metre or more. Exceptions include London and the Thames Estuary and the Amsterdam and Rotterdam (the Netherlands) where adaptation to a rise of sea level of up to 4 m or more appears feasible. This lack of knowledge on sea-level rise thresholds for coastal cities is of concern, and similar

  11. Epstein's Brain Growth Theory as Related to Cognitive Level Matching.

    ERIC Educational Resources Information Center

    Dixon, Roslin Williams

    This paper examines the theories of Herman T. Epstein, who has suggested that there may be a correlation between Piaget's stages of intellectual development and the brain growth stages. Epstein's research has indicated that the human brain grows in spurts rather than in simple linear increments across time. Of special significance to educators is…

  12. Using Cognitive Load Theory to Tailor Instruction to Levels of Accounting Students' Expertise

    ERIC Educational Resources Information Center

    Blayney, Paul; Kalyuga, Slava; Sweller, John

    2015-01-01

    Tailoring of instructional methods to learner levels of expertise may reduce extraneous cognitive load and improve learning. Contemporary technology-based learning environments have the potential to substantially enable learner-adapted instruction. This paper investigates the effects of adaptive instruction based on using the isolated-interactive…

  13. Layer response theory: Energetics of layered materials from semianalytic high-level theory

    NASA Astrophysics Data System (ADS)

    Dobson, John F.; Gould, Tim; Lebègue, Sébastien

    2016-04-01

    We present a readily computable semianalytic layer response theory (LRT) for analysis of cohesive energetics involving two-dimensional layers such as BN or graphene. The theory approximates the random phase approximation (RPA) correlation energy. Its RPA character ensures that the energy has the correct van der Waals asymptotics for well-separated layers, in contrast to simple pairwise atom-atom theories, which fail qualitatively for layers with zero electronic energy gap. At the same time, our theory is much less computationally intensive than the full RPA energy. It also gives accurate correlation energies near the binding minimum, in contrast to Lifshitz-type theory. We apply our LRT successfully to graphite and to BN, and to a graphene-BN heterostructure.

  14. Building a Community Framework for Adaptation to Sea Level Rise and Inundation

    NASA Astrophysics Data System (ADS)

    Culver, M. E.; Schubel, J.; Davidson, M. A.; Haines, J.

    2010-12-01

    Sea level rise and inundation pose a substantial risk to many coastal communities, and the risk is projected to increase because of continued development, changes in the frequency and intensity of inundation events, and acceleration in the rate of sea-level rise. Calls for action at all levels acknowledge that a viable response must engage federal, state and local expertise, perspectives, and resources in a coordinated and collaborative effort. Representatives from a variety of these agencies and organizations have developed a shared framework to help coastal communities structure and facilitate community-wide adaptation processes and to help agencies determine where investments should be made to enable states and local governments to assess impacts and initiate adaptation strategies over the next decade. For sea level rise planning and implementation, the requirements for high-quality data and information are vast and the availability is limited. Participants stressed the importance of data interoperability to ensure that users are able to apply data from a variety of sources and to improve availability and confidence in the data. Participants were able to prioritize the following six categories of data needed to support future sea level rise planning and implementation: - Data to understand land forms and where and how water will flow - Monitoring data and environmental drivers - Consistent sea level rise scenarios and projections across agencies to support local planning - Data to characterize vulnerabilities and impacts of sea level rise - Community characteristics - Legal frameworks and administrative structure. To develop a meaningful and effective sea level rise adaptation plan, state and local planners must understand how the availability, scale, and uncertainty of these types of data will impact new guidelines or adaptation measures. The tools necessary to carry-out the adaptation planning process need to be understood in terms of data requirements

  15. Coastal flood damage and adaptation costs under 21st century sea-level rise.

    PubMed

    Hinkel, Jochen; Lincke, Daniel; Vafeidis, Athanasios T; Perrette, Mahé; Nicholls, Robert James; Tol, Richard S J; Marzeion, Ben; Fettweis, Xavier; Ionescu, Cezar; Levermann, Anders

    2014-03-01

    Coastal flood damage and adaptation costs under 21st century sea-level rise are assessed on a global scale taking into account a wide range of uncertainties in continental topography data, population data, protection strategies, socioeconomic development and sea-level rise. Uncertainty in global mean and regional sea level was derived from four different climate models from the Coupled Model Intercomparison Project Phase 5, each combined with three land-ice scenarios based on the published range of contributions from ice sheets and glaciers. Without adaptation, 0.2-4.6% of global population is expected to be flooded annually in 2100 under 25-123 cm of global mean sea-level rise, with expected annual losses of 0.3-9.3% of global gross domestic product. Damages of this magnitude are very unlikely to be tolerated by society and adaptation will be widespread. The global costs of protecting the coast with dikes are significant with annual investment and maintenance costs of US$ 12-71 billion in 2100, but much smaller than the global cost of avoided damages even without accounting for indirect costs of damage to regional production supply. Flood damages by the end of this century are much more sensitive to the applied protection strategy than to variations in climate and socioeconomic scenarios as well as in physical data sources (topography and climate model). Our results emphasize the central role of long-term coastal adaptation strategies. These should also take into account that protecting large parts of the developed coast increases the risk of catastrophic consequences in the case of defense failure. PMID:24596428

  16. Coastal flood damage and adaptation costs under 21st century sea-level rise

    PubMed Central

    Hinkel, Jochen; Lincke, Daniel; Vafeidis, Athanasios T.; Perrette, Mahé; Nicholls, Robert James; Tol, Richard S. J.; Marzeion, Ben; Fettweis, Xavier; Ionescu, Cezar; Levermann, Anders

    2014-01-01

    Coastal flood damage and adaptation costs under 21st century sea-level rise are assessed on a global scale taking into account a wide range of uncertainties in continental topography data, population data, protection strategies, socioeconomic development and sea-level rise. Uncertainty in global mean and regional sea level was derived from four different climate models from the Coupled Model Intercomparison Project Phase 5, each combined with three land-ice scenarios based on the published range of contributions from ice sheets and glaciers. Without adaptation, 0.2–4.6% of global population is expected to be flooded annually in 2100 under 25–123 cm of global mean sea-level rise, with expected annual losses of 0.3–9.3% of global gross domestic product. Damages of this magnitude are very unlikely to be tolerated by society and adaptation will be widespread. The global costs of protecting the coast with dikes are significant with annual investment and maintenance costs of US$ 12–71 billion in 2100, but much smaller than the global cost of avoided damages even without accounting for indirect costs of damage to regional production supply. Flood damages by the end of this century are much more sensitive to the applied protection strategy than to variations in climate and socioeconomic scenarios as well as in physical data sources (topography and climate model). Our results emphasize the central role of long-term coastal adaptation strategies. These should also take into account that protecting large parts of the developed coast increases the risk of catastrophic consequences in the case of defense failure. PMID:24596428

  17. Higher-order adaptive finite-element methods for Kohn–Sham density functional theory

    SciTech Connect

    Motamarri, P.; Nowak, M.R.; Leiter, K.; Knap, J.; Gavini, V.

    2013-11-15

    We present an efficient computational approach to perform real-space electronic structure calculations using an adaptive higher-order finite-element discretization of Kohn–Sham density-functional theory (DFT). To this end, we develop an a priori mesh-adaption technique to construct a close to optimal finite-element discretization of the problem. We further propose an efficient solution strategy for solving the discrete eigenvalue problem by using spectral finite-elements in conjunction with Gauss–Lobatto quadrature, and a Chebyshev acceleration technique for computing the occupied eigenspace. The proposed approach has been observed to provide a staggering 100–200-fold computational advantage over the solution of a generalized eigenvalue problem. Using the proposed solution procedure, we investigate the computational efficiency afforded by higher-order finite-element discretizations of the Kohn–Sham DFT problem. Our studies suggest that staggering computational savings—of the order of 1000-fold—relative to linear finite-elements can be realized, for both all-electron and local pseudopotential calculations, by using higher-order finite-element discretizations. On all the benchmark systems studied, we observe diminishing returns in computational savings beyond the sixth-order for accuracies commensurate with chemical accuracy, suggesting that the hexic spectral-element may be an optimal choice for the finite-element discretization of the Kohn–Sham DFT problem. A comparative study of the computational efficiency of the proposed higher-order finite-element discretizations suggests that the performance of finite-element basis is competing with the plane-wave discretization for non-periodic local pseudopotential calculations, and compares to the Gaussian basis for all-electron calculations to within an order of magnitude. Further, we demonstrate the capability of the proposed approach to compute the electronic structure of a metallic system containing 1688

  18. Higher-order adaptive finite-element methods for Kohn-Sham density functional theory

    NASA Astrophysics Data System (ADS)

    Motamarri, P.; Nowak, M. R.; Leiter, K.; Knap, J.; Gavini, V.

    2013-11-01

    We present an efficient computational approach to perform real-space electronic structure calculations using an adaptive higher-order finite-element discretization of Kohn-Sham density-functional theory (DFT). To this end, we develop an a priori mesh-adaption technique to construct a close to optimal finite-element discretization of the problem. We further propose an efficient solution strategy for solving the discrete eigenvalue problem by using spectral finite-elements in conjunction with Gauss-Lobatto quadrature, and a Chebyshev acceleration technique for computing the occupied eigenspace. The proposed approach has been observed to provide a staggering 100-200-fold computational advantage over the solution of a generalized eigenvalue problem. Using the proposed solution procedure, we investigate the computational efficiency afforded by higher-order finite-element discretizations of the Kohn-Sham DFT problem. Our studies suggest that staggering computational savings-of the order of 1000-fold-relative to linear finite-elements can be realized, for both all-electron and local pseudopotential calculations, by using higher-order finite-element discretizations. On all the benchmark systems studied, we observe diminishing returns in computational savings beyond the sixth-order for accuracies commensurate with chemical accuracy, suggesting that the hexic spectral-element may be an optimal choice for the finite-element discretization of the Kohn-Sham DFT problem. A comparative study of the computational efficiency of the proposed higher-order finite-element discretizations suggests that the performance of finite-element basis is competing with the plane-wave discretization for non-periodic local pseudopotential calculations, and compares to the Gaussian basis for all-electron calculations to within an order of magnitude. Further, we demonstrate the capability of the proposed approach to compute the electronic structure of a metallic system containing 1688 atoms using

  19. The Role of Self-Theories of Intelligence and Self-Efficacy in Adaptive Help-Seeking by College Students

    ERIC Educational Resources Information Center

    Mihlon, Mildred A.

    2010-01-01

    In this study the role of self-theories of intelligence and self-efficacy on adaptive help-seeking behavior was examined. One-hundred, first-year college students were asked to complete a highly difficult vocabulary task that would ensure universal failure. Performance attributions were assessed in order to determine the students' view of…

  20. A typology of household-level adaptation to coastal flooding and its spatio-temporal patterns.

    PubMed

    Koerth, Jana; Vafeidis, Athanasios T; Carretero, Silvina; Sterr, Horst; Hinkel, Jochen

    2014-01-01

    The predicted sea-level rise and changes in storm surge regimes are expected to lead to an increasing risk of flooding in coastal regions. Accommodation can be an alternative to protection in many areas, with household-level adaptation potentially constituting an important element of such a strategy, as it can significantly reduce costs. To date, a systematic typology of household-level adaptation to coastal flooding does not exist. In order to bridge this gap, we conducted a series of quantitative surveys in different coastal areas in Denmark, Germany and Argentina. We applied a cluster analysis in order to categorise the adaptive behaviour of coastal households. Coastal households were found to cluster in four groups that we term: the comprehensives, the theoreticians, the minimalists and the structurals. With the exception of households focusing on the implementation of high-effort structural measures, our results show the affiliation to these groups to follow a specific temporal sequence. At the same time, large differences in category affiliation exist between the study areas. Risk communication tools can utilise our typology to selectively target specific types of households or to ensure that the information needs of all groups are addressed. PMID:25191638

  1. Temporal learning and list-level proportion congruency: conflict adaptation or learning when to respond?

    PubMed

    Schmidt, James R

    2013-01-01

    The current report presents a temporal learning account as a potential alternative to the conflict adaptation account of list-level proportion congruent effects in the Stroop paradigm. Specifically, retrieval of information about response times on previous trials influences a participant's preparedness to respond at a similar time on following trials. First, an adaptation of the Parallel Episodic Processing (PEP) model is presented, and a list-level effect is produced with a temporal learning mechanism. Next, linear mixed effect model analyses show that temporal learning biases are present in list-level proportion congruent data. A non-conflict experiment is then presented in which a list-level effect is observed with a contrast, rather than congruency, manipulation. Analyses of the experimental and simulated data could not, however, provide a clear picture of whether temporal learning was the sole contributor to the list-level proportion congruent effect. These results do, however, demonstrate that caution is warranted when interpreting list-level proportion congruent effects. PMID:24312413

  2. Temporal Learning and List-Level Proportion Congruency: Conflict Adaptation or Learning When to Respond?

    PubMed Central

    Schmidt, James R.

    2013-01-01

    The current report presents a temporal learning account as a potential alternative to the conflict adaptation account of list-level proportion congruent effects in the Stroop paradigm. Specifically, retrieval of information about response times on previous trials influences a participant's preparedness to respond at a similar time on following trials. First, an adaptation of the Parallel Episodic Processing (PEP) model is presented, and a list-level effect is produced with a temporal learning mechanism. Next, linear mixed effect model analyses show that temporal learning biases are present in list-level proportion congruent data. A non-conflict experiment is then presented in which a list-level effect is observed with a contrast, rather than congruency, manipulation. Analyses of the experimental and simulated data could not, however, provide a clear picture of whether temporal learning was the sole contributor to the list-level proportion congruent effect. These results do, however, demonstrate that caution is warranted when interpreting list-level proportion congruent effects. PMID:24312413

  3. Limits on the adaptability of coastal marshes to rising sea level

    USGS Publications Warehouse

    Kirwan, Matthew L.; Guntenspergen, Glenn R.; D'Alpaos, Andrea; Morris, James T.; Mudd, Simon M.; Temmerman, Stijn

    2010-01-01

    Assumptions of a static landscape inspire predictions that about half of the world's coastal wetlands will submerge during this century in response to sea-level acceleration. In contrast, we use simulations from five numerical models to quantify the conditions under which ecogeomorphic feedbacks allow coastal wetlands to adapt to projected changes in sea level. In contrast to previous sea-level assessments, we find that non-linear feedbacks among inundation, plant growth, organic matter accretion, and sediment deposition, allow marshes to survive conservative projections of sea-level rise where suspended sediment concentrations are greater than ~20 mg/L. Under scenarios of more rapid sea-level rise (e.g., those that include ice sheet melting), marshes will likely submerge near the end of the 21st century. Our results emphasize that in areas of rapid geomorphic change, predicting the response of ecosystems to climate change requires consideration of the ability of biological processes to modify their physical environment.

  4. Adaptive Functioning and Behaviour Problems in Relation to Level of Education in Children and Adolescents with Intellectual Disability

    ERIC Educational Resources Information Center

    de Bildt, A.; Sytema, S.; Kraijer, D.; Sparrow, S.; Minderaa, R.

    2005-01-01

    Background: The interrelationship between adaptive functioning, behaviour problems and level of special education was studied in 186 children with IQs ranging from 61 to 70. The objective was to increase the insight into the contribution of adaptive functioning and general and autistic behaviour problems to the level of education in children with…

  5. A theory of biological relativity: no privileged level of causation.

    PubMed

    Noble, Denis

    2012-02-01

    Must higher level biological processes always be derivable from lower level data and mechanisms, as assumed by the idea that an organism is completely defined by its genome? Or are higher level properties necessarily also causes of lower level behaviour, involving actions and interactions both ways? This article uses modelling of the heart, and its experimental basis, to show that downward causation is necessary and that this form of causation can be represented as the influences of initial and boundary conditions on the solutions of the differential equations used to represent the lower level processes. These insights are then generalized. A priori, there is no privileged level of causation. The relations between this form of 'biological relativity' and forms of relativity in physics are discussed. Biological relativity can be seen as an extension of the relativity principle by avoiding the assumption that there is a privileged scale at which biological functions are determined. PMID:23386960

  6. A theory of biological relativity: no privileged level of causation

    PubMed Central

    Noble, Denis

    2012-01-01

    Must higher level biological processes always be derivable from lower level data and mechanisms, as assumed by the idea that an organism is completely defined by its genome? Or are higher level properties necessarily also causes of lower level behaviour, involving actions and interactions both ways? This article uses modelling of the heart, and its experimental basis, to show that downward causation is necessary and that this form of causation can be represented as the influences of initial and boundary conditions on the solutions of the differential equations used to represent the lower level processes. These insights are then generalized. A priori, there is no privileged level of causation. The relations between this form of ‘biological relativity’ and forms of relativity in physics are discussed. Biological relativity can be seen as an extension of the relativity principle by avoiding the assumption that there is a privileged scale at which biological functions are determined. PMID:23386960

  7. Attention-dependent brief adaptation to contour orientation: a high-level aftereffect for convexity?

    PubMed

    Suzuki, S

    2001-12-01

    In contrast to the abundant literature investigating how orientation coding depends on edges defined by various image features, relatively little is known about how coding of orientation might also depend on the two distinct functional roles that oriented edges commonly play. Oriented lines can delineate outline contours of a figure or they can form texture. The results of five experiments using orientation aftereffects measured with brief tests (27 ms, backward masked; adapt-to-test interval=201 ms) provided evidence that brief stimuli (<135 ms) selectively adapt coding of contour-line orientation rather than coding of line-texture orientation. Furthermore, parametric results revealed that the rapidly adapting aftereffects for contour orientation are characterized by (1) broad orientation tuning (peaking at +/-30 degrees to +/-50 degrees from test orientation), (2) indifference as to how the contours are defined (e.g. bright lines, high-pass-filtered lines, faint lines generated by the spatial inhomogeneity of visual sensitivity), (3) rapid saturation at low contrast energy, (4) strong modulation by selective attention, and (5) relative size tolerance. These characteristics appear to parallel those of cells in the high end of the visual form processing pathway (such as inferotemporal cortex). It is thus suggested that the rapidly adapting contour orientation aftereffects reported here may be mediated by high-level neural units that encode global configurations of orientation (e.g. convexity and concavity). PMID:11738454

  8. Conservative treatment of boundary interfaces for overlaid grids and multi-level grid adaptations

    NASA Technical Reports Server (NTRS)

    Moon, Young J.; Liou, Meng-Sing

    1989-01-01

    Conservative algorithms for boundaray interfaces of overlaid grids are presented. The basic method is zeroth order, and is extended to a higher order method using interpolation and subcell decomposition. The present method, strictly based on a conservative constraint, is tested with overlaid grids for various applications of unsteady and steady supersonic inviscid flows with strong shock waves. The algorithm is also applied to a multi-level grid adaptation in which the next level finer grid is overlaid on the coarse base grid with an arbitrary orientation.

  9. Conservative treatment of boundary interfaces for overlaid grids and multi-level grid adaptations

    NASA Technical Reports Server (NTRS)

    Moon, Young J.; Liou, Meng-Sing

    1989-01-01

    Conservative algorithms for boundary interfaces of overlaid grids are presented. The basic method is zeroth order, and is extended to a higher order method using interpolation and subcell decomposition. The present method, strictly based on a conservative constraint, is tested with overlaid grids for various applications of unsteady and steady supersonic inviscid flows with strong shock waves. The algorithm is also applied to a multi-level grid adaptation in which the next level finer grid is overlaid on the coarse base grid with an arbitrary orientation.

  10. Plasma. beta. -endorphin and stress hormone levels during adaptation and stress

    SciTech Connect

    Lishmanov, Yu.B.; Trifonova, Zh.V.; Tsibin, A.N.; Maslova, L.V.; Dement'eva, L.A.

    1987-09-01

    This paper describes a comparative study of ..beta..-endorphin and stress hormone levels in the blood plasma of rats during stress and adaptation. Immunoreactive ..beta..-endorphin in the blood plasma was assayed by means of a kit after preliminary isolation of the ..beta..-endorphin fraction by affinity chromatography on sepharose; ACTH was assayed with a kit and cortisol, insulin, thyroxine and tri-iodothyronine by means of kits from Izotop. Determination of plasma levels of ..beta..-endorphin and other opioids could evidently be an important method of assessing the state of resistance of the organism to stress.

  11. Adapting Evidence-based Interventions using a Common Theory, Practices, and Principles

    PubMed Central

    Rotheram-Borus, Mary Jane; Swendeman, Dallas; Becker, Kimberly D.

    2013-01-01

    Objective Hundreds of validated evidence-based intervention programs (EBIP) aim to improve families’ well-being, however, most are not broadly adopted. As an alternative diffusion strategy, we created wellness centers to reach families’ everyday lives with a prevention framework. Method At two wellness centers, one in a middle-class neighborhood and one in a low-income neighborhood, popular local activity leaders (instructors of martial arts, yoga, sports, music, dancing, zumba), and motivated parents were trained to be Family Mentors. Trainings focused on a framework which taught synthesized, foundational prevention science theory, practice elements, and principles, applied to specific content areas (parenting, social skills, and obesity). Family Mentors were then allowed to adapt scripts and activities based on their cultural experiences, but were closely monitored and supervised over time. The framework was implemented in a range of activities (summer camps, coaching) aimed at improving social, emotional, and behavioral outcomes. Results Successes and challenges are discussed for: 1) engaging parents and communities; 2) identifying and training Family Mentors to promote children and families’ well-being; and 3) gathering data for supervision, outcome evaluation, and continuous quality improvement (CQI). Conclusion To broadly diffuse prevention to families, far more experimentation is needed with alternative and engaging implementation strategies that are enhanced with knowledge harvested from researchers’ past 30 years of experience creating EBIP. One strategy is to train local parents and popular activity leaders in applying robust prevention science theory, common practice elements, and principles of EBIP. More systematic evaluation of such innovations is needed. PMID:24079747

  12. Linear-scaling symmetry-adapted perturbation theory with scaled dispersion

    SciTech Connect

    Maurer, Simon A.; Beer, Matthias; Lambrecht, Daniel S.; Ochsenfeld, Christian

    2013-11-14

    We present a linear-scaling symmetry-adapted perturbation theory (SAPT) method that is based on an atomic orbital (AO) formulation of zeroth-order SAPT (SAPT0). The non-dispersive terms are realized with linear-scaling cost using both the continuous fast multipole method (CFMM) and the linear exchange (LinK) approach for integral contractions as well as our efficient Laplace-based coupled-perturbed self-consistent field method (DL-CPSCF) for evaluating response densities. The reformulation of the dispersion term is based on our linear-scaling AO Møller-Plesset second-order perturbation theory (AO-MP2) method, that uses our recently introduced QQR-type screening [S. A. Maurer, D. S. Lambrecht, J. Kussmann, and C. Ochsenfeld, J. Chem. Phys. 138, 014101 (2013)] for preselecting numerically significant energy contributions. Similar to scaled opposite-spin MP2, we neglect the exchange-dispersion term in SAPT and introduce a scaling factor for the dispersion term, which compensates for the error and at the same time accounts for basis set incompleteness effects and intramonomer correlation. We show in extensive benchmark calculations that the new scaled-dispersion (sd-)SAPT0 approach provides reliable results for small and large interacting systems where the results with a small 6-31G** basis are roughly comparable to supermolecular MP2 calculations in a triple-zeta basis. The performance of our method is demonstrated with timings on cellulose fragments, DNA systems, and cutouts of a protein-ligand complex with up to 1100 atoms on a single computer core.

  13. A multi-level adaptation model of circulation for the western Indian Ocean

    NASA Astrophysics Data System (ADS)

    Shaji, C.; Bahulayan, N.; Dube, S. K.; Rao, A. D.

    1999-12-01

    A three-dimensional, fully non-linear semi-diagnostic (adaptation) model is described. This model is used to compute the climatological mean circulation and to understand the role of local, steady forcing of the wind and thermohaline forcing on the observed circulation in the western tropical Indian Ocean. The model consists of equations of motion and continuity, sea surface topography, equations of state and temperature, and salinity diffusion equations. While the sea surface topography equation is solved by a successive overrelaxation technique, the other model equations are solved by a leap-frog numerical scheme. Two versions of the model, having 18 and 33 levels in the vertical direction, were prepared to study climatological mean circulation in the western tropical Indian Ocean. The first numerical experiment is carried out with the 18-level adaptation model to study the sensitivity of the solution to different values of eddy coefficients. The main scientific rationale behind these numerical experiments was to obtain the most appropriate values of the eddy coefficients for the realistic computation of climatological circulation in the western tropical Indian Ocean. Three numerical experiments were conducted for the month of February to understand the sensitivity of the model solution to different eddy coefficients. The model reproduced the circulation features during February, even with low values of horizontal and vertical eddy coefficients. In the second experiment, the adaptation model, with 33 levels in the vertical direction, is applied to study the seasonal mean climatological circulation at selected depths during Spring in the western tropical Indian Ocean. Adapted (steady state) results of currents, sea surface topography, temperature and salinity anomaly fields are presented. Reasonable agreement is obtained between the model results on currents and the observational data. The computed anomaly fields for temperature and salinity at selected depths

  14. Accurate Adaptive Level Set Method and Sharpening Technique for Three Dimensional Deforming Interfaces

    NASA Technical Reports Server (NTRS)

    Kim, Hyoungin; Liou, Meng-Sing

    2011-01-01

    In this paper, we demonstrate improved accuracy of the level set method for resolving deforming interfaces by proposing two key elements: (1) accurate level set solutions on adapted Cartesian grids by judiciously choosing interpolation polynomials in regions of different grid levels and (2) enhanced reinitialization by an interface sharpening procedure. The level set equation is solved using a fifth order WENO scheme or a second order central differencing scheme depending on availability of uniform stencils at each grid point. Grid adaptation criteria are determined so that the Hamiltonian functions at nodes adjacent to interfaces are always calculated by the fifth order WENO scheme. This selective usage between the fifth order WENO and second order central differencing schemes is confirmed to give more accurate results compared to those in literature for standard test problems. In order to further improve accuracy especially near thin filaments, we suggest an artificial sharpening method, which is in a similar form with the conventional re-initialization method but utilizes sign of curvature instead of sign of the level set function. Consequently, volume loss due to numerical dissipation on thin filaments is remarkably reduced for the test problems

  15. Presenting Theoretical Ideas Prior to Inquiry Activities Fosters Theory-Level Knowledge

    ERIC Educational Resources Information Center

    Wecker, Christof; Rachel, Alexander; Heran-Dörr, Eva; Waltner, Christine; Wiesner, Hartmut; Fischer, Frank

    2013-01-01

    In the course of inquiry activities similar to those of real scientists, learners are supposed to develop knowledge both on the level of observable phenomena and on the level of explanatory theories. However, some theories involve theoretical entities (e.g., "Weiss domains") that cannot be observed directly and therefore may be hard to…

  16. Intramolecular symmetry-adapted perturbation theory with a single-determinant wavefunction.

    PubMed

    Pastorczak, Ewa; Prlj, Antonio; Gonthier, Jérôme F; Corminboeuf, Clémence

    2015-12-14

    We introduce an intramolecular energy decomposition scheme for analyzing non-covalent interactions within molecules in the spirit of symmetry-adapted perturbation theory (SAPT). The proposed intra-SAPT approach is based upon the Chemical Hamiltonian of Mayer [Int. J. Quantum Chem. 23(2), 341-363 (1983)] and the recently introduced zeroth-order wavefunction [J. F. Gonthier and C. Corminboeuf, J. Chem. Phys. 140(15), 154107 (2014)]. The scheme decomposes the interaction energy between weakly bound fragments located within the same molecule into physically meaningful components, i.e., electrostatic-exchange, induction, and dispersion. Here, we discuss the key steps of the approach and demonstrate that a single-determinant wavefunction can already deliver a detailed and insightful description of a wide range of intramolecular non-covalent phenomena such as hydrogen bonds, dihydrogen contacts, and π - π stacking interactions. Intra-SAPT is also used to shed the light on competing intra- and intermolecular interactions. PMID:26671358

  17. Circuit Design and Simulation of AN Augmented Adaptive Resonance Theory (aart) Neural Network.

    NASA Astrophysics Data System (ADS)

    Ho, Ching-Sung

    This dissertation presents circuit implementations for an binary-input adaptive resonance theory neural network architecture, called the augmented ART-1 neural network (AART1-NN). The AART1-NN is a modification of the popular ART1-NN, developed by Carpenter and Grossberg, and it exhibits the same behavior as the ART1-NN. The AART1-NN is a real -time model, and has the ability to classify an arbitrary set of binary input patterns into different clusters. The design of the AART1-NN circuit is based on a set of coupled nonlinear differential equations that constitute the AART1 -NN model. Various ways are examined to implement an efficient and practical AART1-NN in electronic hardware. They include designing circuits of AART1-NN by means of discrete electronic components, such as operational amplifiers, capacitors, and resistors, digital VLSI circuit, and mixed analog/digital VLSI circuit. The implemented circuit prototypes are verified using the PSpice circuit simulator, running on Sun workstations. Results obtained from PSpice circuit simulations are also compared with results obtained by solving the coupled differential equations numerically. The prototype systems developed in this work can be used as building blocks for larger AART1-NN architectures, as well as for other types of ART architectures that involve the AART1-NN model.

  18. Analog circuit design and implementation of an adaptive resonance theory (ART) neural network architecture

    NASA Astrophysics Data System (ADS)

    Ho, Ching S.; Liou, Juin J.; Georgiopoulos, Michael; Heileman, Gregory L.; Christodoulou, Christos G.

    1993-09-01

    This paper presents an analog circuit implementation for an adaptive resonance theory neural network architecture, called the augmented ART-1 neural network (AART1-NN). The AART1-NN is a modification of the popular ART1-NN, developed by Carpenter and Grossberg, and it exhibits the same behavior as the ART1-NN. The AART1-NN is a real-time model, and has the ability to classify an arbitrary set of binary input patterns into different clusters. The design of the AART1-NN model. The circuit is implemented by utilizing analog electronic components, such as, operational amplifiers, transistors, capacitors, and resistors. The implemented circuit is verified using the PSpice circuit simulator, running on Sun workstations. Results obtained from the PSpice circuit simulation compare favorably with simulation results produced by solving the differential equations numerically. The prototype system developed here can be used as a building block for larger AART1-NN architectures, as well as for other types of ART architectures that involve the AART1-NN model.

  19. Investigations into the Nature of Halogen Bonding Including Symmetry Adapted Perturbation Theory Analyses

    SciTech Connect

    Riley, Kevin E.; Hobza, Pavel

    2008-01-12

    In recent years it has been recognized that, because of their unique properties, halogen bonds have tremendous potential in the development of new pharmaceutical compounds and materials. In this study we investigate the phenomenon of halogen bonding by carrying out ab initio calculations on the halomethane-formaldehyde complexes as well as the fluorine substituted FnH₃-nCX---OCH₂ dimers, where the halogen bonding halogens (X) are chlorine, bromine, and iodine. Coupled cluster (CCSD(T)/aug-cc-pVTZ) calculations indicate that the binding energies for these type of interactions lie in the range between -1.05 kcal/mol (H₃CCl---OCH₂) and -3.72 kcal/mol (F₃CI---OCH₂). One of the most important findings in this study is that, according to symmetry adapted perturbation theory (SAPT) analyses, halogen bonds are largely dependent on both electrostatic and dispersion type interactions. As the halogen atom involved in halogen bonding becomes larger the interaction strength for this type of interaction also gets larger and, interestingly, more electrostatic (and less dispersive) in character. Halogen bonding interactions also become stronger and more electrostatic upon substitution of (the very electronegative) fluorines onto the halomethane molecule.

  20. Explicit control of adaptive automation under different levels of environmental stress.

    PubMed

    Sauer, Jürgen; Kao, Chung-Shan; Wastell, David; Nickel, Peter

    2011-08-01

    This article examines the effectiveness of three different forms of explicit control of adaptive automation under low- and high-stress conditions, operationalised by different levels of noise. In total, 60 participants were assigned to one of three types of automation design (free, prompted and forced choice). They were trained for 4 h on a highly automated simulation of a process control environment, called AutoCAMS. This was followed by a 4-h testing session under noise exposure and quiet conditions. Measures of performance, psychophysiology and subjective reactions were taken. The results showed that all three modes of explicit control of adaptive automation modes were able to attenuate the negative effects of noise. This was partly due to the fact that operators opted for higher levels of automation under noise. It also emerged that forced choice showed marginal advantages over the two other automation modes. Statement of Relevance: This work is relevant to the design of adaptive automation since it emphasises the need to consider the impact of work-related stressors during task completion. During the presence of stressors, different forms of operator support through automation may be required than under more favourable working conditions. PMID:21846313

  1. Double Trouble at High Density: Cross-Level Test of Resource-Related Adaptive Plasticity and Crowding-Related Fitness

    PubMed Central

    Gergs, André; Preuss, Thomas G.; Palmqvist, Annemette

    2014-01-01

    Population size is often regulated by negative feedback between population density and individual fitness. At high population densities, animals run into double trouble: they might concurrently suffer from overexploitation of resources and also from negative interference among individuals regardless of resource availability, referred to as crowding. Animals are able to adapt to resource shortages by exhibiting a repertoire of life history and physiological plasticities. In addition to resource-related plasticity, crowding might lead to reduced fitness, with consequences for individual life history. We explored how different mechanisms behind resource-related plasticity and crowding-related fitness act independently or together, using the water flea Daphnia magna as a case study. For testing hypotheses related to mechanisms of plasticity and crowding stress across different biological levels, we used an individual-based population model that is based on dynamic energy budget theory. Each of the hypotheses, represented by a sub-model, is based on specific assumptions on how the uptake and allocation of energy are altered under conditions of resource shortage or crowding. For cross-level testing of different hypotheses, we explored how well the sub-models fit individual level data and also how well they predict population dynamics under different conditions of resource availability. Only operating resource-related and crowding-related hypotheses together enabled accurate model predictions of D. magna population dynamics and size structure. Whereas this study showed that various mechanisms might play a role in the negative feedback between population density and individual life history, it also indicated that different density levels might instigate the onset of the different mechanisms. This study provides an example of how the integration of dynamic energy budget theory and individual-based modelling can facilitate the exploration of mechanisms behind the regulation

  2. Design guidelines for adapting scientific research articles: An example from an introductory level, interdisciplinary program on soft matter

    NASA Astrophysics Data System (ADS)

    Langbeheim, Elon; Safran, Samuel A.; Yerushalmi, Edit

    2013-01-01

    We present design guidelines for using Adapted Primary Literature (APL) as part of current interdisciplinary topics to introductory physics students. APL is a text genre that allows students to comprehend a scientific article, while maintaining the core features of the communication among scientists, thus representing an authentic scientific discourse. We describe the adaptation of a research paper by Nobel Laureate Paul Flory on phase equilibrium in polymer-solvent mixtures that was presented to high school students in a project-based unit on soft matter. The adaptation followed two design strategies: a) Making explicit the interplay between the theory and experiment. b) Re-structuring the text to map the theory onto the students' prior knowledge. Specifically, we map the theory of polymer-solvent systems onto a model for binary mixtures of small molecules of equal size that was already studied in class.

  3. Adaptive non-local means filtering based on local noise level for CT denoising

    NASA Astrophysics Data System (ADS)

    Li, Zhoubo; Yu, Lifeng; Trzasko, Joshua D.; Fletcher, Joel G.; McCollough, Cynthia H.; Manduca, Armando

    2012-03-01

    Radiation dose from CT scans is an increasing health concern in the practice of radiology. Higher dose scans can produce clearer images with high diagnostic quality, but may increase the potential risk of radiation-induced cancer or other side effects. Lowering radiation dose alone generally produces a noisier image and may degrade diagnostic performance. Recently, CT dose reduction based on non-local means (NLM) filtering for noise reduction has yielded promising results. However, traditional NLM denoising operates under the assumption that image noise is spatially uniform noise, while in CT images the noise level varies significantly within and across slices. Therefore, applying NLM filtering to CT data using a global filtering strength cannot achieve optimal denoising performance. In this work, we have developed a technique for efficiently estimating the local noise level for CT images, and have modified the NLM algorithm to adapt to local variations in noise level. The local noise level estimation technique matches the true noise distribution determined from multiple repetitive scans of a phantom object very well. The modified NLM algorithm provides more effective denoising of CT data throughout a volume, and may allow significant lowering of radiation dose. Both the noise map calculation and the adaptive NLM filtering can be performed in times that allow integration with the clinical workflow.

  4. Making sense in a complex landscape: how the Cynefin Framework from Complex Adaptive Systems Theory can inform health promotion practice.

    PubMed

    Van Beurden, Eric K; Kia, Annie M; Zask, Avigdor; Dietrich, Uta; Rose, Lauren

    2013-03-01

    Health promotion addresses issues from the simple (with well-known cause/effect links) to the highly complex (webs and loops of cause/effect with unpredictable, emergent properties). Yet there is no conceptual framework within its theory base to help identify approaches appropriate to the level of complexity. The default approach favours reductionism--the assumption that reducing a system to its parts will inform whole system behaviour. Such an approach can yield useful knowledge, yet is inadequate where issues have multiple interacting causes, such as social determinants of health. To address complex issues, there is a need for a conceptual framework that helps choose action that is appropriate to context. This paper presents the Cynefin Framework, informed by complexity science--the study of Complex Adaptive Systems (CAS). It introduces key CAS concepts and reviews the emergence and implications of 'complex' approaches within health promotion. It explains the framework and its use with examples from contemporary practice, and sets it within the context of related bodies of health promotion theory. The Cynefin Framework, especially when used as a sense-making tool, can help practitioners understand the complexity of issues, identify appropriate strategies and avoid the pitfalls of applying reductionist approaches to complex situations. The urgency to address critical issues such as climate change and the social determinants of health calls for us to engage with complexity science. The Cynefin Framework helps practitioners make the shift, and enables those already engaged in complex approaches to communicate the value and meaning of their work in a system that privileges reductionist approaches. PMID:22128193

  5. Designing a meta-level architecture in Java for adaptive parallelism by mobile software agents

    NASA Astrophysics Data System (ADS)

    Dominic, Stephen Victor

    Adaptive parallelism refers to a parallel computation that runs on a pool of processors that may join or withdraw from a running computation. In this dissertation, a functional system of agents and agent behaviors for adaptive parallelism is developed. Software agents have the properties of robustness and have capacity for fault-tolerance. Adaptation and fault-tolerance emerge from the interaction of self-directed autonomous software agents for a parallel computation application. The multi-agent system can be considered an object-oriented system with a higher-level architectural component, i.e., a meta level for agent behavior. The meta-level object architecture is based on patterns of behavior and communication for mobile agents, which are developed to support cooperative problem solving in a distributed-heterogeneous computing environment. Although parallel processing is a suggested application domain for mobile agents implemented in the Java language, the development of robust agent behaviors implemented in an efficient manner is an active research area. Performance characteristics for three versions of a pattern recognition problem are used to demonstrate a linear speed-up with efficiency that is compared to research using a traditional client-server protocol in the C language. The best ideas from existing approaches to adaptive parallelism are used to create a single general-purpose paradigm that overcomes problems associated with nodefailure, the use of a single-centralized or shared resource, requirements for clients to actively join a computation, and a variety of other limitations that are associated with existing systems. The multi-agent system, and experiments, show how adaptation and parallelism can be exploited by a meta-architecture for a distributed-scientific application that is of particular interest to design of signal-processing ground stations. To a large extent the framework separates concern for algorithmic design from concern for where and

  6. A self-adaptive mean-shift segmentation approach based on graph theory for high-resolution remote sensing images

    NASA Astrophysics Data System (ADS)

    Chen, Luwan; Han, Ling; Ning, Xiaohong

    2015-12-01

    An auto new segmentation approach based on graph theory which named self-adaptive mean-shift for high-resolution remote sensing images was proposed in this paper. This approach could overcome some defects that classic Mean-Shift must determine the fixed bandwidth through trial many times, and could effectively distinguish the difference between different features in the texture rich region. Segmentation experiments were processed with WorldView satellite image. The results show that the presented method is adaptive, and its speed and precision can satisfy application, so it is a robust automatic segmentation algorithm.

  7. A data based mechanistic approach to nonlinear flood routing and adaptive flood level forecasting

    NASA Astrophysics Data System (ADS)

    Romanowicz, Renata J.; Young, Peter C.; Beven, Keith J.; Pappenberger, Florian

    2008-08-01

    Operational flood forecasting requires accurate forecasts with a suitable lead time, in order to be able to issue appropriate warnings and take appropriate emergency actions. Recent improvements in both flood plain characterization and computational capabilities have made the use of distributed flood inundation models more common. However, problems remain with the application of such models. There are still uncertainties associated with the identifiability of parameters; with the computational burden of calculating distributed estimates of predictive uncertainty; and with the adaptive use of such models for operational, real-time flood inundation forecasting. Moreover, the application of distributed models is complex, costly and requires high degrees of skill. This paper presents an alternative to distributed inundation models for real-time flood forecasting that provides fast and accurate, medium to short-term forecasts. The Data Based Mechanistic (DBM) methodology exploits a State Dependent Parameter (SDP) modelling approach to derive a nonlinear dependence between the water levels measured at gauging stations along the river. The transformation of water levels depends on the relative geometry of the channel cross-sections, without the need to apply rating curve transformations to the discharge. The relationship obtained is used to transform water levels as an input to a linear, on-line, real-time and adaptive stochastic DBM model. The approach provides an estimate of the prediction uncertainties, including allowing for heterescadasticity of the multi-step-ahead forecasting errors. The approach is illustrated using an 80 km reach of the River Severn, in the UK.

  8. Root adaptations at stress levels of nitrate, phosphate, or both simultaneously

    SciTech Connect

    Gutschick, V.P.; Kay, L.E.

    1984-08-01

    Sunflowers in flowing hydroponic culture show reduced growth rates at nitrate levels below 10 ..mu..M nitrate or phosphate levels below 0.3 ..mu..F. At least for phosphate, this level is a very small fraction (0.003) of the K/sub m/ for the uptake systems. We have quantified four major adaptations that enable high growth rates under incipient stress: increased root:shoot ratio; increased uptake capacity (V/sub max/) per unit root mass; nocturnal uptake of nutrients; and (only partially adaptive) reduced tissue concentrations of nutrients. We show that capital energy costs (in root growth) for acquiring nutrients can exceed direct or operational costs of internal metabolism (nitrate reduction, e.g.,); this has implications for the plant-controlled trade-off of NO/sub 3//sup -/-NH/sub 4//sup +/ - N/sub 2/ as N sources for legumes and other plant types. We outline needed further research and suggest guidelines for breeding plants for tolerating nutritional stresses; we also suggest that some measures of nutrient-use efficiency may be misleading. 6 references, 2 figures, 2 tables.

  9. Mice and rats achieve similar levels of performance in an adaptive decision-making task

    PubMed Central

    Jaramillo, Santiago; Zador, Anthony M.

    2014-01-01

    Two opposing constraints exist when choosing a model organism for studying the neural basis of adaptive decision-making: (1) experimental access and (2) behavioral complexity. Available molecular and genetic approaches for studying neural circuits in the mouse fulfill the first requirement. In contrast, it is still under debate if mice can perform cognitive tasks of sufficient complexity. Here we compare learning and performance of mice and rats, the preferred behavioral rodent model, during an acoustic flexible categorization two-alternative choice task. The task required animals to switch between two categorization definitions several times within a behavioral session. We found that both species achieved similarly high performance levels. On average, rats learned the task faster than mice, although some mice were as fast as the average rat. No major differences in subjective categorization boundaries or the speed of adaptation between the two species were found. Our results demonstrate that mice are an appropriate model for the study of the neural mechanisms underlying adaptive decision-making, and suggest they might be suitable for other cognitive tasks as well. PMID:25278849

  10. Adapting to climate change despite scientific uncertainty: A case study of coastal protection from sea-level rise in Kiribati

    NASA Astrophysics Data System (ADS)

    Donner, S. D.

    2013-12-01

    Climate change adaptation is an increasing focus of international aid. At recent meetings of the parties to the United Nations Framework Convention on Climate Change (UNFCCC), the developed world agreed to rapidly increase international assistance to help developing countries, like the low-lying island nation of Kiribati, respond to the impacts of climate change. These emerging adaptation efforts must proceed despite the large and partially irreducible scientific uncertainty about the magnitude of those future climate impacts. In this study, we use the example of efforts to adapt to sea-level rise in Kiribati to document the challenges facing such internationally-funded climate change adaptation projects given the scientific uncertainty about climate impacts. Drawing on field and document research, we describe the scientific uncertainty about projected sea-level rise in Tarawa, the capital of Kiribati, how that uncertainty can create trade-offs between adaptation measures, and the social, political and economic context in which adaptation decisions must be made. The analysis shows there is no 'silver bullet' adaptation strategy in countries like Kiribati, given the long-term scientific uncertainty about sea-level rise and the environment of climate change aid. The existence of irreducible scientific uncertainty does not preclude effective climate change adaptation, but instead requires adaptation programs that embrace multiple strategies and planning horizons, and continually build on and re-adjust previous investments. This work highlights the importance of sustained international climate change financing, as proposed in UNFCCC negotiations.

  11. Spatial assignment of symmetry adapted perturbation theory interaction energy components: The atomic SAPT partition

    NASA Astrophysics Data System (ADS)

    Parrish, Robert M.; Sherrill, C. David

    2014-07-01

    We develop a physically-motivated assignment of symmetry adapted perturbation theory for intermolecular interactions (SAPT) into atom-pairwise contributions (the A-SAPT partition). The basic precept of A-SAPT is that the many-body interaction energy components are computed normally under the formalism of SAPT, following which a spatially-localized two-body quasiparticle interaction is extracted from the many-body interaction terms. For electrostatics and induction source terms, the relevant quasiparticles are atoms, which are obtained in this work through the iterative stockholder analysis (ISA) procedure. For the exchange, induction response, and dispersion terms, the relevant quasiparticles are local occupied orbitals, which are obtained in this work through the Pipek-Mezey procedure. The local orbital atomic charges obtained from ISA additionally allow the terms involving local orbitals to be assigned in an atom-pairwise manner. Further summation over the atoms of one or the other monomer allows for a chemically intuitive visualization of the contribution of each atom and interaction component to the overall noncovalent interaction strength. Herein, we present the intuitive development and mathematical form for A-SAPT applied in the SAPT0 approximation (the A-SAPT0 partition). We also provide an efficient series of algorithms for the computation of the A-SAPT0 partition with essentially the same computational cost as the corresponding SAPT0 decomposition. We probe the sensitivity of the A-SAPT0 partition to the ISA grid and convergence parameter, orbital localization metric, and induction coupling treatment, and recommend a set of practical choices which closes the definition of the A-SAPT0 partition. We demonstrate the utility and computational tractability of the A-SAPT0 partition in the context of side-on cation-π interactions and the intercalation of DNA by proflavine. A-SAPT0 clearly shows the key processes in these complicated noncovalent interactions, in

  12. Spatial assignment of symmetry adapted perturbation theory interaction energy components: The atomic SAPT partition

    SciTech Connect

    Parrish, Robert M.; Sherrill, C. David

    2014-07-28

    We develop a physically-motivated assignment of symmetry adapted perturbation theory for intermolecular interactions (SAPT) into atom-pairwise contributions (the A-SAPT partition). The basic precept of A-SAPT is that the many-body interaction energy components are computed normally under the formalism of SAPT, following which a spatially-localized two-body quasiparticle interaction is extracted from the many-body interaction terms. For electrostatics and induction source terms, the relevant quasiparticles are atoms, which are obtained in this work through the iterative stockholder analysis (ISA) procedure. For the exchange, induction response, and dispersion terms, the relevant quasiparticles are local occupied orbitals, which are obtained in this work through the Pipek-Mezey procedure. The local orbital atomic charges obtained from ISA additionally allow the terms involving local orbitals to be assigned in an atom-pairwise manner. Further summation over the atoms of one or the other monomer allows for a chemically intuitive visualization of the contribution of each atom and interaction component to the overall noncovalent interaction strength. Herein, we present the intuitive development and mathematical form for A-SAPT applied in the SAPT0 approximation (the A-SAPT0 partition). We also provide an efficient series of algorithms for the computation of the A-SAPT0 partition with essentially the same computational cost as the corresponding SAPT0 decomposition. We probe the sensitivity of the A-SAPT0 partition to the ISA grid and convergence parameter, orbital localization metric, and induction coupling treatment, and recommend a set of practical choices which closes the definition of the A-SAPT0 partition. We demonstrate the utility and computational tractability of the A-SAPT0 partition in the context of side-on cation-π interactions and the intercalation of DNA by proflavine. A-SAPT0 clearly shows the key processes in these complicated noncovalent interactions, in

  13. Elastic, not plastic species: Frozen plasticity theory and the origin of adaptive evolution in sexually reproducing organisms

    PubMed Central

    2010-01-01

    Background Darwin's evolutionary theory could easily explain the evolution of adaptive traits (organs and behavioral patterns) in asexual but not in sexual organisms. Two models, the selfish gene theory and frozen plasticity theory were suggested to explain evolution of adaptive traits in sexual organisms in past 30 years. Results The frozen plasticity theory suggests that sexual species can evolve new adaptations only when their members are genetically uniform, i.e. only after a portion of the population of the original species had split off, balanced on the edge of extinction for several generations, and then undergone rapid expansion. After a short period of time, estimated on the basis of paleontological data to correspond to 1-2% of the duration of the species, polymorphism accumulates in the gene pool due to frequency-dependent selection; and thus, in each generation, new mutations occur in the presence of different alleles and therefore change their selection coefficients from generation to generation. The species ceases to behave in an evolutionarily plastic manner and becomes evolutionarily elastic on a microevolutionary time-scale and evolutionarily frozen on a macroevolutionary time-scale. It then exists in this state until such changes accumulate in the environment that the species becomes extinct. Conclusion Frozen plasticity theory, which includes the Darwinian model of evolution as a special case - the evolution of species in a plastic state, not only offers plenty of new predictions to be tested, but also provides explanations for a much broader spectrum of known biological phenomena than classic evolutionary theories. Reviewers This article was reviewed by Rob Knight, Fyodor Kondrashov and Massimo Di Giulio (nominated by David H. Ardell). PMID:20067646

  14. Broken-symmetry-adapted Green function theory of condensed matter systems: Towards a vector spin-density-functional theory

    NASA Astrophysics Data System (ADS)

    Rajagopal, A. K.; Mochena, Mogus

    2000-12-01

    The group-theory framework developed by Fukutome for a systematic analysis of the various broken-symmetry types of Hartree-Fock solution exhibiting spin structures is here extended to the general many-body context using spinor Green function formalism for describing magnetic systems. Consequences of this theory are discussed for examining the magnetism of itinerant electrons in nanometric systems of current interest as well as bulk systems where a vector spin-density form is required, by specializing our work to spin-density-functional formalism. We also formulate the linear-response theory for such a system and compare and contrast our results with the recent results obtained for localized electron systems. The various phenomenological treatments of itinerant magnetic systems are here unified in this group-theoretical description. We apply this theory to the one-band Hubbard model to illustrate the usefulness of this approach.

  15. High-fidelity interface tracking in compressible flows: Unlimited anchored adaptive level set

    NASA Astrophysics Data System (ADS)

    Nourgaliev, R. R.; Theofanous, T. G.

    2007-06-01

    The interface-capturing-fidelity issue of the level set method is addressed wholly within the Eulerian framework. Our aim is for a practical and efficient way to realize the expected benefits of grid resolution and high order schemes. Based on a combination of structured adaptive mesh refinement (SAMR), rather than quad/octrees, and on high-order spatial discretization, rather than the use of Lagrangian particles, our method is tailored to compressible flows, while it provides a potentially useful alternative to the particle level set (PLS) for incompressible flows. Interesting salient features of our method include (a) avoidance of limiting (in treating the Hamiltonian of the level set equation), (b) anchoring the level set in a manner that ensures no drift and no spurious oscillations of the zero level during PDE-reinitialization, and (c) a non-linear tagging procedure for defining the neighborhood of the interface subject to mesh refinement. Numerous computational results on a set of benchmark problems (strongly deforming, stretching and tearing interfaces) demonstrate that with this approach, implemented up to 11th order accuracy, the level set method becomes essentially free of mass conservation errors and also free of parasitic interfacial oscillations, while it is still highly efficient, and convenient for 3D parallel implementation. In addition, demonstration of performance in fully-coupled simulations is presented for multimode Rayleigh-Taylor instability (low-Mach number regime) and shock-induced, bubble-collapse (highly compressible regime).

  16. An adaptive level set approach for incompressible two-phase flows

    SciTech Connect

    Sussman, M.; Almgren, A.S.; Bell, J.B.

    1997-04-01

    In Sussman, Smereka and Osher, a numerical method using the level set approach was formulated for solving incompressible two-phase flow with surface tension. In the level set approach, the interface is represented as the zero level set of a smooth function; this has the effect of replacing the advection of density, which has steep gradients at the interface, with the advection of the level set function, which is smooth. In addition, the interface can merge or break up with no special treatment. The authors maintain the level set function as the signed distance from the interface in order to robustly compute flows with high density ratios and stiff surface tension effects. In this work, they couple the level set scheme to an adaptive projection method for the incompressible Navier-Stokes equations, in order to achieve higher resolution of the interface with a minimum of additional expense. They present two-dimensional axisymmetric and fully three-dimensional results of air bubble and water drop computations.

  17. Ground-Based Research on Vestibular Adaptation to G-Level Transitions

    NASA Astrophysics Data System (ADS)

    Groen, Eric L.; Nooij, Suzanne A. E.; Bos, Jelte E.

    2008-06-01

    At TNO research is ongoing on neuro-vestibular adaptation to altered G-levels. It is well-known that during the first days in weightlessness 50-80% of all astronauts suffer from the Space Adaptation Syndrome (SAS), which involves space motion sickness, spatial disorientation and motion illusions. After return on Earth the problems re-appear, but now also accompanied by postural imbalance. Standard tests for motion sickness, typically applied in astronaut selection programs, do not correlate with SAS at all. TNO developed a method which effectively simulates SAS on Earth, by exposing astronauts to a hypergravity stimulus of 3G in a human centrifuge for one hour. So far we tested the susceptibility for SIC in 12 astronauts and cosmonauts who also rated their susceptibility for SAS in actual spaceflight. The correlation is 100%, suggesting a common mechanism for any G-level transition, whether it is from 1G to 0G or from 3G to 1G. This paper describes the current status of this research.

  18. A Cartesian Adaptive Level Set Method for Two-Phase Flows

    NASA Technical Reports Server (NTRS)

    Ham, F.; Young, Y.-N.

    2003-01-01

    In the present contribution we develop a level set method based on local anisotropic Cartesian adaptation as described in Ham et al. (2002). Such an approach should allow for the smallest possible Cartesian grid capable of resolving a given flow. The remainder of the paper is organized as follows. In section 2 the level set formulation for free surface calculations is presented and its strengths and weaknesses relative to the other free surface methods reviewed. In section 3 the collocated numerical method is described. In section 4 the method is validated by solving the 2D and 3D drop oscilation problem. In section 5 we present some results from more complex cases including the 3D drop breakup in an impulsively accelerated free stream, and the 3D immiscible Rayleigh-Taylor instability. Conclusions are given in section 6.

  19. Introduction of a Classical Level in Quantum Theory - Continuous Monitoring

    NASA Astrophysics Data System (ADS)

    Prosperi, G. M.

    2016-07-01

    In an old paper of our group in Milano a formalism was introduced for the continuous monitoring of a system during a certain interval of time in the framework of a somewhat generalized approach to quantum mechanics (QM). The outcome was a distribution of probability on the space of all the possible continuous histories of a set of quantities to be considered as a kind of coarse grained approximation to some ordinary quantum observables commuting or not. In fact the main aim was the introduction of a classical level in the context of QM, treating formally a set of basic quantities, to be considered as beables in the sense of Bell, as continuously taken under observation. However the effect of such assumption was a permanent modification of the Liouville-von Neumann equation for the statistical operator by the introduction of a dissipative term which is in conflict with basic conservation rules in all reasonable models we had considered. Difficulties were even encountered for a relativistic extension of the formalism. In this paper I propose a modified version of the original formalism which seems to overcome both difficulties. First I study the simple models of an harmonic oscillator and a free scalar field in which a coarse grain position and a coarse grained field respectively are treated as beables. Then I consider the more realistic case of spinor electrodynamics in which only certain coarse grained electric and magnetic fields are introduced as classical variables and no matter related quantities.

  20. Adaptation to Sea Level Rise in Coastal Units of the National Park Service (Invited)

    NASA Astrophysics Data System (ADS)

    Beavers, R. L.

    2010-12-01

    National Park units with Natural, Cultural and Historic Resource-based data products and management documents that will aid the parks in better managing aspects of storm-preparedness and post-storm response and recovery. These results as well as specific efforts to address vulnerability of NPS facilities and natural and cultural resources to sea level rise will be discussed. NPS is also coordinating with NOAA to fill a new position for coastal adaptation and apply the information learned from research, vulnerability studies, and work with partners to develop adaptation strategies for coastal and ocean parks. To adapt to sea level rise, NPS will develop strong policies, guidance, and interpretive materials to help parks take actions that will increase the resilience of ocean and coastal park biological and geologic resources, reduce inappropriate stressors and greenhouse gas emissions in ocean and coastal parks, and educate the public about the need for comprehensive, swift and effective measures that will help the NPS conserve ocean and coastal park resources for future generations.

  1. Interpretive Research Aiming at Theory Building: Adopting and Adapting the Case Study Design

    ERIC Educational Resources Information Center

    Diaz Andrade, Antonio

    2009-01-01

    Although the advantages of case study design are widely recognised, its original positivist underlying assumptions may mislead interpretive researchers aiming at theory building. The paper discusses the limitations of the case study design for theory building and explains how grounded theory systemic process adds to the case study design. The…

  2. Numerical Relations and Skill Level Constrain Co-Adaptive Behaviors of Agents in Sports Teams

    PubMed Central

    Silva, Pedro; Travassos, Bruno; Vilar, Luís; Aguiar, Paulo; Davids, Keith; Araújo, Duarte; Garganta, Júlio

    2014-01-01

    Similar to other complex systems in nature (e.g., a hunting pack, flocks of birds), sports teams have been modeled as social neurobiological systems in which interpersonal coordination tendencies of agents underpin team swarming behaviors. Swarming is seen as the result of agent co-adaptation to ecological constraints of performance environments by collectively perceiving specific possibilities for action (affordances for self and shared affordances). A major principle of invasion team sports assumed to promote effective performance is to outnumber the opposition (creation of numerical overloads) during different performance phases (attack and defense) in spatial regions adjacent to the ball. Such performance principles are assimilated by system agents through manipulation of numerical relations between teams during training in order to create artificially asymmetrical performance contexts to simulate overloaded and underloaded situations. Here we evaluated effects of different numerical relations differentiated by agent skill level, examining emergent inter-individual, intra- and inter-team coordination. Groups of association football players (national – NLP and regional-level – RLP) participated in small-sided and conditioned games in which numerical relations between system agents were manipulated (5v5, 5v4 and 5v3). Typical grouping tendencies in sports teams (major ranges, stretch indices, distances of team centers to goals and distances between the teams' opposing line-forces in specific team sectors) were recorded by plotting positional coordinates of individual agents through continuous GPS tracking. Results showed that creation of numerical asymmetries during training constrained agents' individual dominant regions, the underloaded teams' compactness and each team's relative position on-field, as well as distances between specific team sectors. We also observed how skill level impacted individual and team coordination tendencies. Data revealed

  3. Numerical relations and skill level constrain co-adaptive behaviors of agents in sports teams.

    PubMed

    Silva, Pedro; Travassos, Bruno; Vilar, Luís; Aguiar, Paulo; Davids, Keith; Araújo, Duarte; Garganta, Júlio

    2014-01-01

    Similar to other complex systems in nature (e.g., a hunting pack, flocks of birds), sports teams have been modeled as social neurobiological systems in which interpersonal coordination tendencies of agents underpin team swarming behaviors. Swarming is seen as the result of agent co-adaptation to ecological constraints of performance environments by collectively perceiving specific possibilities for action (affordances for self and shared affordances). A major principle of invasion team sports assumed to promote effective performance is to outnumber the opposition (creation of numerical overloads) during different performance phases (attack and defense) in spatial regions adjacent to the ball. Such performance principles are assimilated by system agents through manipulation of numerical relations between teams during training in order to create artificially asymmetrical performance contexts to simulate overloaded and underloaded situations. Here we evaluated effects of different numerical relations differentiated by agent skill level, examining emergent inter-individual, intra- and inter-team coordination. Groups of association football players (national--NLP and regional-level--RLP) participated in small-sided and conditioned games in which numerical relations between system agents were manipulated (5v5, 5v4 and 5v3). Typical grouping tendencies in sports teams (major ranges, stretch indices, distances of team centers to goals and distances between the teams' opposing line-forces in specific team sectors) were recorded by plotting positional coordinates of individual agents through continuous GPS tracking. Results showed that creation of numerical asymmetries during training constrained agents' individual dominant regions, the underloaded teams' compactness and each team's relative position on-field, as well as distances between specific team sectors. We also observed how skill level impacted individual and team coordination tendencies. Data revealed emergence of

  4. An Adaptation Strategy to Address Sea Level Rise Along Coastal Developments

    NASA Astrophysics Data System (ADS)

    Trivedi, D. R.

    2010-12-01

    understanding of acceptable levels of risks, a strategy encompassing the near-term, mid-term, and long term was developed for the projects. Immovable structures such as buildings and vital infrastructure will be raised to above the conservative levels of identified sea level rise. Perimeter improvements would be built to mid-term values with adaptation strategies incorporated into the project documents.

  5. Clearance of low levels of HCV viremia in the absence of a strong adaptive immune response

    PubMed Central

    Meyer, Manuela F; Lehmann, Marc; Cornberg, Markus; Wiegand, Johannes; Manns, Michael P; Klade, Christoph; Wedemeyer, Heiner

    2007-01-01

    Spontaneous clearance of hepatitis C virus (HCV) has frequently been associated with the presence of HCV-specific cellular immunity. However, there had been also reports in chimpanzees demonstrating clearance of HCV-viremia in the absence of significant levels of detectable HCV-specific cellular immune responses. We here report seven asymptomatic acute hepatitis C cases with peak HCV-RNA levels between 300 and 100.000 copies/ml who all cleared HCV-RNA spontaneously. Patients were identified by a systematic screening of 1176 consecutive new incoming offenders in a German young offender institution. Four of the seven patients never developed anti-HCV antibodies and had normal ALT levels throughout follow-up. Transient weak HCV-specific CD4+ T cell responses were detectable in five individuals which did not differ in strength and breadth from age- and sex-matched patients with chronic hepatitis C and long-term recovered patients. In contrast, HCV-specific MHC-class-I-tetramer-positive cells were found in 3 of 4 HLA-A2-positive patients. Thus, these cases highlight that clearance of low levels of HCV viremia is possible in the absence of a strong adaptive immune response which might explain the low seroconversion rate after occupational exposure to HCV. PMID:17562015

  6. Blood Oxygen Level-Dependent Activation of the Primary Visual Cortex Predicts Size Adaptation Illusion

    PubMed Central

    Pooresmaeili, Arezoo; Arrighi, Roberto; Biagi, Laura; Morrone, Maria Concetta

    2016-01-01

    In natural scenes, objects rarely occur in isolation but appear within a spatiotemporal context. Here, we show that the perceived size of a stimulus is significantly affected by the context of the scene: brief previous presentation of larger or smaller adapting stimuli at the same region of space changes the perceived size of a test stimulus, with larger adapting stimuli causing the test to appear smaller than veridical and vice versa. In a human fMRI study, we measured the blood oxygen level-dependent activation (BOLD) responses of the primary visual cortex (V1) to the contours of large-diameter stimuli and found that activation closely matched the perceptual rather than the retinal stimulus size: the activated area of V1 increased or decreased, depending on the size of the preceding stimulus. A model based on local inhibitory V1 mechanisms simulated the inward or outward shifts of the stimulus contours and hence the perceptual effects. Our findings suggest that area V1 is actively involved in reshaping our perception to match the short-term statistics of the visual scene. PMID:24089504

  7. Reconstruction based finger-knuckle-print verification with score level adaptive binary fusion.

    PubMed

    Gao, Guangwei; Zhang, Lei; Yang, Jian; Zhang, Lin; Zhang, David

    2013-12-01

    Recently, a new biometrics identifier, namely finger knuckle print (FKP), has been proposed for personal authentication with very interesting results. One of the advantages of FKP verification lies in its user friendliness in data collection. However, the user flexibility in positioning fingers also leads to a certain degree of pose variations in the collected query FKP images. The widely used Gabor filtering based competitive coding scheme is sensitive to such variations, resulting in many false rejections. We propose to alleviate this problem by reconstructing the query sample with a dictionary learned from the template samples in the gallery set. The reconstructed FKP image can reduce much the enlarged matching distance caused by finger pose variations; however, both the intra-class and inter-class distances will be reduced. We then propose a score level adaptive binary fusion rule to adaptively fuse the matching distances before and after reconstruction, aiming to reduce the false rejections without increasing much the false acceptances. Experimental results on the benchmark PolyU FKP database show that the proposed method significantly improves the FKP verification accuracy. PMID:24043391

  8. Impact of farm level adaptation to climate change on agricultural productivity and farmers' wellbeing: Empirical evidence from Pakistan

    NASA Astrophysics Data System (ADS)

    Abid, Muhammad; Scheffran, Jürgen

    2016-04-01

    Climate change is projected to adversely affect the agricultural sector and attached rural livelihoods, particularly in the developing countries. Hence adaptation to climate change is crucial to support agricultural productivity and rural livelihoods. The current study is based on comprehensive cross sectional data collected through 450 face-to-face interviews with farmers from three agro-ecological zones of Punjab province, Pakistan. This paper aims to examine the factors that influence the farmers' adaptation decisions and to assess the impact of farm level adaptation on crop productivity and farmers' wellbeing. The paper uses correlation analysis, binary logistic regression and propensity score matching techniques in order to explore the study objectives. The results of the study indicate that education, age, land holdings, farmer-to-farmer interaction, access to weather forecasting information and location in agro-ecological zone does have significant impact on farmers' decision to adapt to climate change. Major adaptation measures adopted by farmers were changing planting dates, changing cropping varieties, planting shaded trees and changing input-mix. Moreover the study found a positive and significant impact of adaptation on productivity of all major crops (wheat, sugarcane, maize and rice) and on farmers' wellbeing in term of farm income. Furthermore, the study also found that the extent of adaptation benefits increases with the number of adaptation measures. The findings of the study suggest to focus on farmers' education and easy access to climate-specific information for better adaptation at farm level and improved farm wellbeing. Key words: Climate change; Farm level adaptation; crop productivity; farmers' wellbeing; Pakistan

  9. Grid coupling mechanism in the semi-implicit adaptive Multi-Level Multi-Domain method

    NASA Astrophysics Data System (ADS)

    Innocenti, M. E.; Tronci, C.; Markidis, S.; Lapenta, G.

    2016-05-01

    The Multi-Level Multi-Domain (MLMD) method is a semi-implicit adaptive method for Particle-In-Cell plasma simulations. It has been demonstrated in the past in simulations of Maxwellian plasmas, electrostatic and electromagnetic instabilities, plasma expansion in vacuum, magnetic reconnection [1, 2, 3]. In multiple occasions, it has been commented on the coupling between the coarse and the refined grid solutions. The coupling mechanism itself, however, has never been explored in depth. Here, we investigate the theoretical bases of grid coupling in the MLMD system. We obtain an evolution law for the electric field solution in the overlap area of the MLMD system which highlights a dependance on the densities and currents from both the coarse and the refined grid, rather than from the coarse grid alone: grid coupling is obtained via densities and currents.

  10. Genetic adaptation to levels of dietary selenium in recent human history.

    PubMed

    White, Louise; Romagné, Frédéric; Müller, Elias; Erlebach, Eva; Weihmann, Antje; Parra, Genís; Andrés, Aida M; Castellano, Sergi

    2015-06-01

    As humans migrated around the world, they came to inhabit environments that differ widely in the soil levels of certain micronutrients, including selenium (Se). Coupled with cultural variation in dietary practices, these migrations have led to a wide range of Se intake levels in populations around the world. Both excess and deficiency of Se in the diet can have adverse health consequences in humans, with severe Se deficiency resulting in diseases of the bone and heart. Se is required by humans mainly due to its function in selenoproteins, which contain the amino acid selenocysteine as one of their constituent residues. To understand the evolution of the use of this micronutrient in humans, we surveyed the patterns of polymorphism in all selenoprotein genes and genes involved in their regulation in 50 human populations. We find that single nucleotide polymorphisms from populations in Asia, particularly in populations living in the extreme Se-deficient regions of China, have experienced concerted shifts in their allele frequencies. Such differentiation in allele frequencies across genes is not observed in other regions of the world and is not expected under neutral evolution, being better explained by the action of recent positive selection. Thus, recent changes in the use and regulation of Se may harbor the genetic adaptations that helped humans inhabit environments that do not provide adequate levels of Se in the diet. PMID:25739735

  11. An adaptive multi-level simulation algorithm for stochastic biological systems

    NASA Astrophysics Data System (ADS)

    Lester, C.; Yates, C. A.; Giles, M. B.; Baker, R. E.

    2015-01-01

    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

  12. Using Projections of Tidal Marsh Ecosystem Response to Sea-Level Rise to Guide Adaptation Planning

    NASA Astrophysics Data System (ADS)

    Veloz, S.; Nur, N.; Salas, L. A.; Stralberg, D.; Jongsomjit, D.; Wood, J.; Liu, L.; Ballard, G.

    2011-12-01

    The large uncertainty associated with estimating the effects of sea-level rise and climate change on tidal marsh ecosystems exacerbates the difficulty in planning for their effective conservation. To address this uncertainty, we modeled the distribution and abundance of tidal marsh bird species in the San Francisco Estuary for the period 2010 to 2110 in relation to projected changes in sea-level rise, salinity, and sediment availability using four future scenarios with assumptions of low or high suspended sediment concentrations and low or high rates of sea-level rise (0.52 or 1.65 m/100 yr). We used the projections of bird populations the modeled uncertainty to develop spatially explicit priorities for conservation and restoration using Zonation conservation planning software. In our models, marsh bird population generally declined from current levels due to the conversion of high and mid-marsh habitat to low-marsh and mudflats and changes in spring and summer salinity. High sea-level rise scenarios had the biggest impact on bird populations, although the effects were muted under high sediment availability scenarios. There was considerable variation in bird population projections among the four future scenarios we tested and the uncertainty tended to increase from 2030 to 2110. Because so little tidal marsh habitat currently remains in the San Francisco Estuary, the spatial prioritization found that all areas currently open to tidal influence were high priorities for conservation. We repeated this prioritization exercise with all barriers to tidal flow (e.g. levees) removed and identified important locations in which restoration by breaching levees would most efficiently provide long-term benefit to tidal marsh bird populations. The projected species distributions and changes in tidal marsh elevations are available in the form of interactive maps and downloadable GIS layers at: www.prbo.org/sfbayslr. This website can help managers plan effective conservation and

  13. An adaptive multi-level simulation algorithm for stochastic biological systems

    SciTech Connect

    Lester, C. Giles, M. B.; Baker, R. E.; Yates, C. A.

    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

  14. Operationalizing Levels of Academic Mastery Based on Vygotsky's Theory: The Study of Mathematical Knowledge

    ERIC Educational Resources Information Center

    Nezhnov, Peter; Kardanova, Elena; Vasilyeva, Marina; Ludlow, Larry

    2015-01-01

    The present study tested the possibility of operationalizing levels of knowledge acquisition based on Vygotsky's theory of cognitive growth. An assessment tool (SAM-Math) was developed to capture a hypothesized hierarchical structure of mathematical knowledge consisting of procedural, conceptual, and functional levels. In Study 1, SAM-Math was…

  15. Toward a Mechanics of Adaptive Behavior: Evolutionary Dynamics and Matching Theory Statics

    ERIC Educational Resources Information Center

    McDowell, J. J.; Popa, Andrei

    2010-01-01

    One theory of behavior dynamics instantiates the idea that behavior evolves in response to selection pressure from the environment in the form of reinforcement. This computational theory implements Darwinian principles of selection, reproduction, and mutation, which operate on a population of potential behaviors by means of a genetic algorithm.…

  16. The Glass Menagerie as heuristic for explicating nursing theory.

    PubMed

    Pilkington, F Beryl; Frederickson, Keville; Velsasco-Whetsell, Martha

    2006-07-01

    Tennessee Williams' play, The Glass Menagerie, is interpreted through the lens of two different nursing theories, the Roy adaptation model and the human becoming theory. In the Roy adaptation model interpretation, adaptive levels of reality testing and stimuli that instigate withdrawal are explored, while in the human becoming theory interpretation, the themes of meaning, rhythmicity, and contranscendence are explicated. PMID:16757781

  17. On the Use of Adaptive Instructional Images Based on the Sequential-Global Dimension of the Felder-Silverman Learning Style Theory

    ERIC Educational Resources Information Center

    Filippidis, Stavros K.; Tsoukalas, Ioannis A.

    2009-01-01

    An adaptive educational system that uses adaptive presentation is presented. In this system fragments of different images present the same content and the system can choose the one most relevant to the user based on the sequential-global dimension of Felder-Silverman's learning style theory. In order to retrieve the learning style of each student…

  18. Current Understanding of the Formation and Adaptation of Metabolic Systems Based on Network Theory

    PubMed Central

    Takemoto, Kazuhiro

    2012-01-01

    Formation and adaptation of metabolic networks has been a long-standing question in biology. With recent developments in biotechnology and bioinformatics, the understanding of metabolism is progressively becoming clearer from a network perspective. This review introduces the comprehensive metabolic world that has been revealed by a wide range of data analyses and theoretical studies; in particular, it illustrates the role of evolutionary events, such as gene duplication and horizontal gene transfer, and environmental factors, such as nutrient availability and growth conditions, in evolution of the metabolic network. Furthermore, the mathematical models for the formation and adaptation of metabolic networks have also been described, according to the current understanding from a perspective of metabolic networks. These recent findings are helpful in not only understanding the formation of metabolic networks and their adaptation, but also metabolic engineering. PMID:24957641

  19. A self-adaptive oriented particles Level-Set method for tracking interfaces

    NASA Astrophysics Data System (ADS)

    Ianniello, S.; Di Mascio, A.

    2010-02-01

    A new method for tracking evolving interfaces by lagrangian particles in conjunction with a Level-Set approach is introduced. This numerical technique is based on the use of time evolution equations for fundamental vector and tensor quantities defined on the front and represents a new and convenient way to couple the advantages of the Eulerian description given by a Level-Set function ϕ to the use of Lagrangian massless particles. The term oriented points out that the information advected by the particles not only concern the spatial location, but also the local (outward) normal vector n to the interface Γ and the second fundamental tensor (the shape operator) ∇n. The particles are exactly located upon Γ and provide all the requested information for tracking the interface on their own. In addition, a self-adaptive mechanism suitably modifies, at each time step, the markers distribution in the numerical domain: each particle behaves both as a potential seeder of new markers on Γ (so as to guarantee an accurate reconstruction of the interface) and a de-seeder (to avoid any useless gathering of markers and to limit the computational effort). The algorithm is conceived to avoid any transport equation for ϕ and to confine the Level-Set function to the role of a mere post-processing tool; thus, all the numerical diffusion problems usually affecting the Level-Set methodology are removed. The method has been tested both on 2D and 3D configurations; it carries out a fast reconstruction of the interface and its accuracy is only limited by the spatial resolution of the mesh.

  20. A theory of cerebellar cortex and adaptive motor control based on two types of universal function approximation capability.

    PubMed

    Fujita, Masahiko

    2016-03-01

    Lesions of the cerebellum result in large errors in movements. The cerebellum adaptively controls the strength and timing of motor command signals depending on the internal and external environments of movements. The present theory describes how the cerebellar cortex can control signals for accurate and timed movements. A model network of the cerebellar Golgi and granule cells is shown to be equivalent to a multiple-input (from mossy fibers) hierarchical neural network with a single hidden layer of threshold units (granule cells) that receive a common recurrent inhibition (from a Golgi cell). The weighted sum of the hidden unit signals (Purkinje cell output) is theoretically analyzed regarding the capability of the network to perform two types of universal function approximation. The hidden units begin firing as the excitatory inputs exceed the recurrent inhibition. This simple threshold feature leads to the first approximation theory, and the network final output can be any continuous function of the multiple inputs. When the input is constant, this output becomes stationary. However, when the recurrent unit activity is triggered to decrease or the recurrent inhibition is triggered to increase through a certain mechanism (metabotropic modulation or extrasynaptic spillover), the network can generate any continuous signals for a prolonged period of change in the activity of recurrent signals, as the second approximation theory shows. By incorporating the cerebellar capability of two such types of approximations to a motor system, in which learning proceeds through repeated movement trials with accompanying corrections, accurate and timed responses for reaching the target can be adaptively acquired. Simple models of motor control can solve the motor error vs. sensory error problem, as well as the structural aspects of credit (or error) assignment problem. Two physiological experiments are proposed for examining the delay and trace conditioning of eyelid responses, as

  1. Tinkering with Perfection: Theory Development in the Intervention Cultural Adaptation Field

    ERIC Educational Resources Information Center

    Ferrer-Wreder, Laura; Sundell, Knut; Mansoory, Shahram

    2012-01-01

    Background: Testing evidence-based interventions (EBIs) outside of their home country has become increasingly commonplace. There is a need for theoretically guided research on how to best create and test the effects of culturally adapted interventions. Objective: To illustrate how the field might raise the scientific and practical value of future…

  2. Rational Adaptation under Task and Processing Constraints: Implications for Testing Theories of Cognition and Action

    ERIC Educational Resources Information Center

    Howes, Andrew; Lewis, Richard L.; Vera, Alonso

    2009-01-01

    The authors assume that individuals adapt rationally to a utility function given constraints imposed by their cognitive architecture and the local task environment. This assumption underlies a new approach to modeling and understanding cognition--cognitively bounded rational analysis--that sharpens the predictive acuity of general, integrated…

  3. An Enhanced Approach to Combine Item Response Theory with Cognitive Diagnosis in Adaptive Testing

    ERIC Educational Resources Information Center

    Wang, Chun; Zheng, Chanjin; Chang, Hua-Hua

    2014-01-01

    Computerized adaptive testing offers the possibility of gaining information on both the overall ability and cognitive profile in a single assessment administration. Some algorithms aiming for these dual purposes have been proposed, including the shadow test approach, the dual information method (DIM), and the constraint weighted method. The…

  4. Adaptive ultrasonic measurement of blood vessel diameter and wall thickness: theory and experimental results.

    PubMed

    Rafii, K; Jaffe, J S

    1998-01-01

    An adaptive ultrasonic technique for measuring blood vessel diameter and wall thickness is presented. This technique allows one to use a target-specific transmitted waveform/receiver filter to obtain a larger signal-to-noise ratio (SNR) in the received signal than conventional techniques. Generally, SNR of a received wave increases as the intensity of the transmit wave increases; however, because of the FDA limitations placed on the amount of transmit energy, it is important to be able to make the most efficient use of the energy that is available to obtain the best possible SNR in the received signal. Adaptive ultrasonic measurement makes the most efficient use of the energy that is available by placing the maximum amount of energy in the largest target scattering mode. This results in more energy backscatter from a given target, which leads to a higher SNR in the received waveform. Computer simulations of adaptive ultrasonic measurement of blood vessel diameter show that for a SNR of 0 dB in the transmitted waveform, the standard deviation of the diameter measurements for a custom-designed transmitted waveform is about two orders of magnitude less than the standard deviation of the diameter measurements using more conventional waveforms. Diameter and wall thickness measurement experiments were performed on a latex tube and a bovine blood vessel using both custom-made and conventionally used transmitted waveforms. Results show that the adaptively designed waveform gives a smaller uncertainty in the measurements. The adaptive ultrasonic blood vessel diameter and wall thickness measuring technique has potential applications in examining vessels which are either too deep inside the body or too small for conventional techniques to be used, because of the low SNR in the received signal. PMID:18244211

  5. [Urbanization mechanisms in bird species: population systems transformations or adaptations at the individual level?].

    PubMed

    Fridman, V S; Eremkin, G S; Zakharova-Kubareva, N Iu

    2008-01-01

    The present research deals with urbanization of wild bird and mammal species. Forms and mechanisms of population steadiness in the urban landscape have been examined. The urbanization process turned out to be a directed change of the population system forming de novo in the urbolandscape leading to a sustainable organization peculiar for the particular environment. The population organization of different types in urbolandscape is found to provide its stability under conditions of directed and fast changes accompanied with instability and heterogenous structure of habitats. It is shown that the same type of population organization meets the corresponding demands among different species settling in the urban environment. Its features are "openness" and "flowage" of the groups, far order of settlement levels and other units of population system, constant movements of the individuals between the groups as a respond to the signals of urboenvironment significant changes. The "urban" variant of the population system organization turns out to be opposite to that of the same species in the non-urban habitats. After formation of the urban types by the species and successful developing of the town, the urban population becomes separated from the maternal local population and begins to exist independently in the urban landscape. The variety of adaptation aberrations in ecology, behavior, and mode of life of urban birds is the population system stability function in the urban landscape and is not a results of individual selection. It is shown that the urbanization process of the species goes firstly on the population level being the system structure transformation developed by the species towards the most stable state in the town (city) territory. Only after the appearance of stable urban population, the urban individuals show the rapid growth of different changes in ecology, behavior, mode of life that was traditionally described by naturalists as species adaptation to the

  6. An Adaptive Management Approach for Summer Water Level Reductions on the Upper Mississippi River System

    USGS Publications Warehouse

    Johnson, B.L.; Barko, J.W.; Clevenstine, R.; Davis, M.; Galat, D.L.; Lubinski, S.J.; Nestler, J.M.

    2010-01-01

    The primary purpose of this report is to provide an adaptive management approach for learning more about summer water level reductions (drawdowns) as a management tool, including where and how drawdowns can be applied most effectively within the Upper Mississippi River System. The report reviews previous drawdowns conducted within the system and provides specific recommendations for learning more about the lesser known effects of drawdowns and how the outcomes can be influenced by different implementation strategies and local conditions. The knowledge gained can be used by managers to determine how best to implement drawdowns in different parts of the UMRS to help achieve management goals. The information and recommendations contained in the report are derived from results of previous drawdown projects, insights from regional disciplinary experts, and the experience of the authors in experimental design, modeling, and monitoring. Modeling is a critical part of adaptive management and can involve conceptual models, simulation models, and empirical models. In this report we present conceptual models that express current understanding regarding functioning of the UMRS as related to drawdowns and highlight interactions among key ecological components of the system. The models were developed within the constraints of drawdown timing, magnitude (depth), and spatial differences in effects (longitudinal and lateral) with attention to ecological processes affected by drawdowns. With input from regional experts we focused on the responses of vegetation, fish, mussels, other invertebrates, and birds. The conceptual models reflect current understanding about relations and interactions among system components, the expected strength of those interactions, potential responses of system components to drawdowns, likelihood of the response occurring, and key uncertainties that limit our ability to make accurate predictions of effects (Table 1, Fig. 4-10). Based on this current

  7. Modern Models of Psychosocial Adaptation to Chronic Illness and Disability as Viewed through the Prism of Lewin's Field Theory: A Comparative Review

    ERIC Educational Resources Information Center

    Livneh, Hanoch; Bishop, Malachy; Anctil, Tina M.

    2014-01-01

    Purpose: In this article, we describe how four recent models of psychosocial adaptation to chronic illness and disability (CID) could be fruitfully conceptualized and compared by resorting to the general framework of Lewin's field theory--a theory frequently regarded as a precursor and the primary impetus to the development of the field of…

  8. Interest level in 2-year-olds with autism spectrum disorder predicts rate of verbal, nonverbal, and adaptive skill acquisition.

    PubMed

    Klintwall, Lars; Macari, Suzanne; Eikeseth, Svein; Chawarska, Katarzyna

    2015-11-01

    Recent studies have suggested that skill acquisition rates for children with autism spectrum disorders receiving early interventions can be predicted by child motivation. We examined whether level of interest during an Autism Diagnostic Observation Schedule assessment at 2 years predicts subsequent rates of verbal, nonverbal, and adaptive skill acquisition to the age of 3 years. A total of 70 toddlers with autism spectrum disorder, mean age of 21.9 months, were scored using Interest Level Scoring for Autism, quantifying toddlers' interest in toys, social routines, and activities that could serve as reinforcers in an intervention. Adaptive level and mental age were measured concurrently (Time 1) and again after a mean of 16.3 months of treatment (Time 2). Interest Level Scoring for Autism score, Autism Diagnostic Observation Schedule score, adaptive age equivalent, verbal and nonverbal mental age, and intensity of intervention were entered into regression models to predict rates of skill acquisition. Interest level at Time 1 predicted subsequent acquisition rate of adaptive skills (R(2) = 0.36) and verbal mental age (R(2) = 0.30), above and beyond the effects of Time 1 verbal and nonverbal mental ages and Autism Diagnostic Observation Schedule scores. Interest level at Time 1 also contributed (R(2) = 0.30), with treatment intensity, to variance in development of nonverbal mental age. PMID:25398893

  9. Forward-Inverse Adaptive Techniques for Reservoir Characterization and Simulation: Theory and Applications

    SciTech Connect

    Doss, S D; Ezzedine, S; Gelinas, R; Chawathe, A

    2001-06-11

    A novel approach called Forward-Inverse Adaptive Techniques (FIAT) for reservoir characterization is developed and applied to three representative exploration cases. Inverse modeling refers to the determination of the entire reservoir permeability under steady state single-phase flow regime, given only field permeability, pressure and production well measurements. FIAT solves the forward and inverse partial differential equations (PDEs) simultaneously by adding a regularization term and filtering pressure gradients. An implicit adaptive-grid, Galerkin, numerical scheme is used to numerically solve the set of PDEs subject to pressure and permeability boundary conditions. Three examples are presented. Results from all three cases demonstrate attainable and reasonably accurate solutions and, more importantly, provide insights into the consequences of data undersampling.

  10. Cerebral Arteries Extraction using Level Set Segmentation and Adaptive Tracing for CT Angiography

    SciTech Connect

    Zhang Yong; Zhou Xiaobo; Srinivasan, Ranga; Wong, Stephen T. C.; Young, Geoff

    2007-11-02

    We propose an approach for extracting cerebral arteries from partial Computed Tomography Angiography (CTA). The challenges of extracting cerebral arteries from CTA come from the fact that arteries are usually surrounded by bones and veins in the lower portion of a CTA volume. There exists strong intensity-value overlap between vessels and surrounding objects. Besides, it is inappropriate to assume the 2D cross sections of arteries are circle or ellipse, especially for abnormal vessels. The navigation of the arteries could change suddenly in the 3D space. In this paper, a method based on level set segmentation is proposed to target this challenging problem. For the lower portion of a CTA volume, we use geodesic active contour method to detect cross section of arteries in the 2D space. The medial axis of the artery is obtained by adaptively tracking along its navigation path. This is done by finding the minimal cross section from cutting the arteries under different angles in the 3D spherical space. This method is highly automated, with minimum user input of providing only the starting point and initial navigation direction of the arteries of interests.

  11. 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

  12. Warming reduces metabolic rate in marine snails: adaptation to fluctuating high temperatures challenges the metabolic theory of ecology

    PubMed Central

    Marshall, David J.; McQuaid, Christopher D.

    2011-01-01

    The universal temperature-dependence model (UTD) of the metabolic theory of ecology (MTE) proposes that temperature controls mass-scaled, whole-animal resting metabolic rate according to the first principles of physics (Boltzmann kinetics). Controversy surrounds the model's implication of a mechanistic basis for metabolism that excludes the effects of adaptive regulation, and it is unclear how this would apply to organisms that live in fringe environments and typically show considerable metabolic adaptation. We explored thermal scaling of metabolism in a rocky-shore eulittoral-fringe snail (Echinolittorina malaccana) that experiences constrained energy gain and fluctuating high temperatures (between 25°C and approximately 50°C) during prolonged emersion (weeks). In contrast to the prediction of the UTD model, metabolic rate was often negatively related to temperature over a benign range (30–40°C), the relationship depending on (i) the temperature range, (ii) the degree of metabolic depression (related to the quiescent period), and (iii) whether snails were isolated within their shells. Apparent activation energies (E) varied between 0.05 and −0.43 eV, deviating excessively from the UTD's predicted range of between 0.6 and 0.7 eV. The lowering of metabolism when heated should improve energy conservation in a high-temperature environment and challenges both the theory's generality and its mechanistic basis. PMID:20685714

  13. A Hamiltonian theory of adaptive resolution simulations of classical and quantum models of nuclei

    NASA Astrophysics Data System (ADS)

    Kreis, Karsten; Donadio, Davide; Kremer, Kurt; Potestio, Raffaello

    2015-03-01

    Quantum delocalization of atomic nuclei strongly affects the physical properties of low temperature systems, such as superfluid helium. However, also at room temperature nuclear quantum effects can play an important role for molecules composed by light atoms. An accurate modeling of these effects is possible making use of the Path Integral formulation of Quantum Mechanics. In simulations, this numerically expensive description can be restricted to a small region of space, while modeling the remaining atoms as classical particles. In this way the computational resources required can be significantly reduced. In the present talk we demonstrate the derivation of a Hamiltonian formulation for a bottom-up, theoretically solid coupling between a classical model and a Path Integral description of the same system. The coupling between the two models is established with the so-called Hamiltonian Adaptive Resolution Scheme, resulting in a fully adaptive setup in which molecules can freely diffuse across the classical and the Path Integral regions by smoothly switching their description on the fly. Finally, we show the validation of the approach by means of adaptive resolution simulations of low temperature parahydrogen. Graduate School Materials Science in Mainz, Staudinger Weg 9, 55128 Mainz, Germany.

  14. A local coastal adaptation pathway

    NASA Astrophysics Data System (ADS)

    Barnett, J.; Graham, S.; Mortreux, C.; Fincher, R.; Waters, E.; Hurlimann, A.

    2014-12-01

    Local governments are not adapting to sea-level rise because it is difficult to build consensus on the need for change and the best way to implement it. In theory, adaptation pathways can resolve this impasse. Adaptation pathways are a sequence of linked strategies that are triggered by a change in environmental conditions, and in which initial decisions can have low regrets and preserve options for future generations. We report on a project that sought to empirically test the relevance and feasibility of a local pathway for adapting to sea-level rise. We find that triggers of change that have social impacts are salient to local people, and developing a local adaptation pathway helps build consensus among diverse constituencies. Our results show that adaptation pathways are feasible at the local scale, offering a low-risk, low-cost way to begin the long process of adaptation to sea-level rise.

  15. Social Anxiety and Social Adaptation among Adolescents at Three Age Levels

    ERIC Educational Resources Information Center

    Peleg, Ora

    2012-01-01

    The aim of the study was to examine the relationship between social anxiety and social adaptation among adolescents. This is the first study to research these parameters among three age groups: early, middle and late adolescence. On the whole, a negative relation was found between social anxiety and social adaptation. Specifically, for adolescents…

  16. Empirically Estimating the Potential for Farm-Level Adaptation to Climate Change in Western European Agriculture

    NASA Astrophysics Data System (ADS)

    Moore, F. C.; Lobell, D. B.

    2013-12-01

    Agriculture is one of the economic sectors most exposed to climate change and estimating the sensitivity of food production to these changes is critical for determining the severity of climate change impacts and for informing both adaptation and mitigation policy. While climate change might have adverse effects in many areas, it has long been recognized that farmers have a suite of adaptation options at their disposal including, inter alia, changing planting date, varieties, crops, or the mix and quantity of inputs applied. These adaptations may significantly reduce the adverse impacts of climate change but the potential effectiveness of these options and the speed with which farmers will adopt them remain uncertain. We estimate the sensitivity of crop yields and farm profits in western Europe to climate change with and without the adoption of on-farm adaptations. We use cross-sectional variation across farms to define the long-run response function that includes adaptation and inter-annual variation within farms to define the short-run response function without adaptation. The difference between these can be interpreted as the potential for adaptation. We find that future warming will have a large adverse impact on wheat and barley yields and that adaptation will only be able to mitigate a small fraction of this. Maize, oilseed and sugarbeet yields are more modestly affected and adaptation is more effective for these crops. Farm profits could increase slightly under moderate amounts of warming if adaptations are adopted but will decline in the absence of adaptation. A decomposition of variance gives the relative importance of different sources of uncertainty in projections of climate change impacts. We find that in most cases uncertainty over future adaptation pathways (whether farmers will or will not adopt beneficial adaptations) is the most important source of uncertainty in projecting the effect of temperature changes on crop yields and farm profits. This

  17. Adapting SAFT-γ perturbation theory to site-based molecular dynamics simulation. I. Homogeneous fluids

    SciTech Connect

    Ghobadi, Ahmadreza F.; Elliott, J. Richard

    2013-12-21

    In this work, we aim to develop a version of the Statistical Associating Fluid Theory (SAFT)-γ equation of state (EOS) that is compatible with united-atom force fields, rather than experimental data. We rely on the accuracy of the force fields to provide the relation to experimental data. Although, our objective is a transferable theory of interfacial properties for soft and fused heteronuclear chains, we first clarify the details of the SAFT-γ approach in terms of site-based simulations for homogeneous fluids. We show that a direct comparison of Helmholtz free energy to molecular simulation, in the framework of a third order Weeks-Chandler-Andersen perturbation theory, leads to an EOS that takes force field parameters as input and reproduces simulation results for Vapor-Liquid Equilibria (VLE) calculations. For example, saturated liquid density and vapor pressure of n-alkanes ranging from methane to dodecane deviate from those of the Transferable Potential for Phase Equilibria (TraPPE) force field by about 0.8% and 4%, respectively. Similar agreement between simulation and theory is obtained for critical properties and second virial coefficient. The EOS also reproduces simulation data of mixtures with about 5% deviation in bubble point pressure. Extension to inhomogeneous systems and united-atom site types beyond those used in description of n-alkanes will be addressed in succeeding papers.

  18. The effects of country-level population policy for enhancing adaptation to climate change

    NASA Astrophysics Data System (ADS)

    Gunasekara, N. K.; Kazama, S.; Yamazaki, D.; Oki, T.

    2013-11-01

    The effectiveness of population policy in reducing the combined impacts of population change and climate change on water resources is explored. One no-policy scenario and two scenarios with population policy assumptions are employed in combination with water availability under the SRES scenarios A1b, B1 and A2 for the impact analysis. The population data used are from the World Bank. The river discharges per grid of horizontal resolution 0.5° are obtained from the Total Runoff Integrating Pathways (TRIP) of the University of Tokyo, Japan. Unlike the population scenarios utilized in the SRES emission scenarios and the newest representative concentration pathways, the scenarios employed in this research are based, even after 2050, on country-level rather than regional-level growth assumptions. Our analysis implies that the heterogeneous pattern of population changes across the world is the dominant driver of water stress, irrespective of future greenhouse gas emissions, with highest impacts occurring in the already water-stressed low latitudes. In 2100, Africa, Middle East and parts of Asia are under extreme water stress under all scenarios. The sensitivity analysis reveals that a small reduction in populations over the region could relieve a large number of people from high water stress, while a further increase in population from the assumed levels (SC1) might not increase the number of people under high water stress considerably. Most of the population increase towards 2100 occurs in the already water-stressed lower latitudes. Therefore, population reduction policies are recommended for this region as a method of adaptation to the future water stress conditions. Population reduction policies will facilitate more control over their future development pathways, even if these countries were not able to contribute significantly to greenhouse gas (GHG) emission cuts due to economic constraints. However, for the European region, the population living in water

  19. Following Alice: Theories of Critical Thinking and Reflective Practice in Action at Postgraduate Level

    ERIC Educational Resources Information Center

    Swanwick, Ruth; Kitchen, Ruth; Jarvis, Joy; McCracken, Wendy; O'Neil, Rachel; Powers, Steve

    2014-01-01

    This paper presents a flexible framework of principles for teaching critical thinking and reflective practice skills at the postgraduate level. It reports on a collaborative project between four UK institutions providing postgraduate programmes in deaf education. Through a critical review of current theories of critical thinking and reflective…

  20. Educational Evaluation in the Light of Construal Level Theory: The Case of Cognitive Tuning

    ERIC Educational Resources Information Center

    Kovac, Velibor B.; Langfeldt, Gjert

    2010-01-01

    The aim of the present study is to examine the relation between stakeholders as internal evaluators and their systemic positions in light of construal level theory. The study examines the two samples of county representatives, teachers and principals who answered the questionnaire regarding evaluation of the Norwegian assessment program. In…

  1. Estimating Reliability of School-Level Scores Using Multilevel and Generalizability Theory Models

    ERIC Educational Resources Information Center

    Jeon, Min-Jeong; Lee, Guemin; Hwang, Jeong-Won; Kang, Sang-Jin

    2009-01-01

    The purpose of this study was to investigate the methods of estimating the reliability of school-level scores using generalizability theory and multilevel models. Two approaches, "student within schools" and "students within schools and subject areas," were conceptualized and implemented in this study. Four methods resulting from the combination…

  2. Employability Competencies for Entry Level Occupations in Electronics. Part One: Basic Theory.

    ERIC Educational Resources Information Center

    Werner, Claire

    This syllabus, which is the first of a two-volume set describing the basic competencies needed by entry-level workers in the field of electronics, deals with the basic theories of electricity and electronics. Competencies are organized according to the following skills areas: the meaning of electricity, how electricity works, resistors, Ohm's law,…

  3. Ply level failure prediction of carbon fibre reinforced laminated composite panels subjected to low velocity drop-weight impact using adaptive meshing techniques

    NASA Astrophysics Data System (ADS)

    Farooq, Umar; Myler, Peter

    2014-09-01

    This work is concerned with physical testing and numerical simulations of flat and round nose drop-weight impact of carbon fibre-reinforced laminate composite panels to predict ply level failure. Majority of the existing studies on impact of composites by spherical nose impactors are experimental, computational models are simplified, and based on classical laminated plate theories where contributions of through-thickness stresses are neglected. Present work considers flat nose impact and contributions from through-thickness stresses and is mainly simulation based. A computational model was developed in ABAQUS™ software using adaptive meshing techniques. Simulation produced (2D model) stresses were numerically integrated using MATALB™ code to predict through-thickness (3D) stresses. Through-the-thickness stresses were then utilised in advanced failure criteria coded in MATLAB™ software to predict ply level failures. Simulation produced results demonstrate that the computational model can efficiently and effectively predict ply-by-ply failure status of relatively thick laminates.

  4. Uncertainty in adaptive capacity

    NASA Astrophysics Data System (ADS)

    Adger, W. Neil; Vincent, Katharine

    2005-03-01

    The capacity to adapt is a critical element of the process of adaptation: it is the vector of resources that represent the asset base from which adaptation actions can be made. Adaptive capacity can in theory be identified and measured at various scales, from the individual to the nation. The assessment of uncertainty within such measures comes from the contested knowledge domain and theories surrounding the nature of the determinants of adaptive capacity and the human action of adaptation. While generic adaptive capacity at the national level, for example, is often postulated as being dependent on health, governance and political rights, and literacy, and economic well-being, the determinants of these variables at national levels are not widely understood. We outline the nature of this uncertainty for the major elements of adaptive capacity and illustrate these issues with the example of a social vulnerability index for countries in Africa. To cite this article: W.N. Adger, K. Vincent, C. R. Geoscience 337 (2005).

  5. Interest Level in 2-Year-Olds with Autism Spectrum Disorder Predicts Rate of Verbal, Nonverbal, and Adaptive Skill Acquisition

    ERIC Educational Resources Information Center

    Klintwall, Lars; Macari, Suzanne; Eikeseth, Svein; Chawarska, Katarzyna

    2015-01-01

    Recent studies have suggested that skill acquisition rates for children with autism spectrum disorders receiving early interventions can be predicted by child motivation. We examined whether level of interest during an Autism Diagnostic Observation Schedule assessment at 2?years predicts subsequent rates of verbal, nonverbal, and adaptive skill…

  6. Gravitoinertial force background level affects adaptation to coriolis force perturbations of reaching movements

    NASA Technical Reports Server (NTRS)

    Lackner, J. R.; Dizio, P.

    1998-01-01

    We evaluated the combined effects on reaching movements of the transient, movement-dependent Coriolis forces and the static centrifugal forces generated in a rotating environment. Specifically, we assessed the effects of comparable Coriolis force perturbations in different static force backgrounds. Two groups of subjects made reaching movements toward a just-extinguished visual target before rotation began, during 10 rpm counterclockwise rotation, and after rotation ceased. One group was seated on the axis of rotation, the other 2.23 m away. The resultant of gravity and centrifugal force on the hand was 1.0 g for the on-center group during 10 rpm rotation, and 1.031 g for the off-center group because of the 0.25 g centrifugal force present. For both groups, rightward Coriolis forces, approximately 0.2 g peak, were generated during voluntary arm movements. The endpoints and paths of the initial per-rotation movements were deviated rightward for both groups by comparable amounts. Within 10 subsequent reaches, the on-center group regained baseline accuracy and straight-line paths; however, even after 40 movements the off-center group had not resumed baseline endpoint accuracy. Mirror-image aftereffects occurred when rotation stopped. These findings demonstrate that manual control is disrupted by transient Coriolis force perturbations and that adaptation can occur even in the absence of visual feedback. An increase, even a small one, in background force level above normal gravity does not affect the size of the reaching errors induced by Coriolis forces nor does it affect the rate of reacquiring straight reaching paths; however, it does hinder restoration of reaching accuracy.

  7. [Adaptation and Neurosciences II: Biological, Psychological and Social Adaptation, and Psychopathology].

    PubMed

    Desseilles, Martin

    2016-01-01

    In this article, we address adaptation in relation to the neurosciences. Adaptation is examined at the individual as well as various environmental levels: biological, psychological, and social. We then briefly discuss, from a neuroscientific perspective, the concept of adaptation in relation to psychopathology, including attachment theory and the third wave of cognitive-behavioral therapies. PMID:27570964

  8. Constraints on Tree-Level Higher Order Gravitational Couplings in Superstring Theory

    NASA Astrophysics Data System (ADS)

    Stieberger, Stephan

    2011-03-01

    We consider the scattering amplitudes of five and six gravitons at tree level in superstring theory. Their power series expansions in the Regge slope α' are analyzed through the order α'8 showing some interesting constraints on higher order gravitational couplings in the effective superstring action such as the absence of R5 terms. Furthermore, some transcendentality constraints on the coefficients of the nonvanishing couplings are observed: the absence of zeta values of even weight through the order α'8 like the absence of ζ(2)ζ(3)R6 terms. Our analysis is valid for any superstring background in any space-time dimension, which allows for a conformal field theory description.

  9. Plasma GLP-2 levels and intestinal markers in the juvenile pig during intestinal adaptation: effects of different diet regimens.

    PubMed

    Paris, Monique C; Fuller, Peter J; Carstensen, Bendix; Nagy, Eva; Taylor, Russell G; Sourial, Magdy; Holst, Jens J; Hartmann, Bolette; Binesm, Julie E

    2004-10-01

    Adaptation of the residual small bowel following resection is dependent on luminal and humoral factors. We aimed to establish if circulating levels of glucagon-like peptide (GLP-2) change under different dietary regimens following resection and to determine if there is a relationship between plasma GLP-2 levels and markers of intestinal adaptation. Four-week-old piglets underwent a 75% proximal small bowel resection (n = 31) or transection (n = 14). Postoperatively they received either pig chow (n = 14), nonpolymeric (elemental) infant formula (n = 7), or polymeric infant formula alone (n = 8) or supplemented either with fiber (n = 6) or with bovine colostrum protein concentrate (CPC; n = 10) for 8 weeks until sacrifice. Plasma GLP-2 levels were measured at weeks 0, 2, 4, and 8 postoperatively. In addition, end-stage parameters were studied at week 8 including weight gain, ileal villus height, crypt depth, and disaccharidase levels. Plasma GLP-2 levels were higher in resected animals compared to transected animals fed the same diet. Plasma GLP-2 levels were significantly increased in the colostrum protein isolate-supplemented animals following resection compared to all other diet groups. The increase in plasma GLP-2 (pM) was greatest in the first 2 weeks postresection (week 0, 15.5; week 2, 30.9), followed by a plateau at weeks 2 to 4 and a decrease in GLP-2 levels from week 4 to week 8. At week 8, no relationships were found between the plasma GLP-2 levels and the measurements of weight gain, villus height, lactase, sucrase, maltase, crypt depth, or villus/crypt ratio. Plasma GLP-2 levels increase in the first weeks following massive small intestinal resection. The increase in plasma GLP-2 levels was enhanced by supplementation of the diet with CPC. The changes in GLP-2 levels observed in this study may suggest that GLP-2 plays a role in the adaptive response in the intestine following resection in this preclinical model. PMID:15573929

  10. r-adaptive methods based on element-level error indicators for parallel analysis of plates and shells

    NASA Technical Reports Server (NTRS)

    Militello, Carmelo; Felippa, Carlos A.

    1992-01-01

    The formulation and application of element-level error indicators based on parametrized variational principles are investigated. These indicators are ideally suited to drive adaptive mesh refinment on parallel computers where access to neighboring elements resident on different processors may incur significant computational overhead. Furthermore, such estimators are not affected by physical jumps at wavefronts or interfaces. An estimator derived from the higher-order element energy is applied to r adaptation of meshes in plates and shell structures where the exact solution is known.

  11. Nested Levels of Adaptive Divergence: The Genetic Basis of Craniofacial Divergence and Ecological Sexual Dimorphism

    PubMed Central

    Parsons, Kevin J.; Wang, Jason; Anderson, Graeme; Albertson, R. Craig

    2015-01-01

    Exemplary systems for adaptive divergence are often characterized by their large degrees of phenotypic variation. This variation represents the outcome of generations of diversifying selection. However, adaptive radiations can also contain a hierarchy of differentiation nested within them where species display only subtle phenotypic differences that still have substantial effects on ecology, function, and ultimately fitness. Sexual dimorphisms are also common in species displaying adaptive divergence and can be the result of differential selection between sexes that produce ecological differences between sexes. Understanding the genetic basis of subtle variation (between certain species or sexes) is therefore important for understanding the process of adaptive divergence. Using cichlids from the dramatic adaptive radiation of Lake Malawi, we focus on understanding the genetic basis of two aspects of relatively subtle phenotypic variation. This included a morphometric comparison of the patterns of craniofacial divergence between two ecologically similar species in relation to the larger adaptive radiation of Malawi, and male–female morphological divergence between their F2 hybrids. We then genetically map craniofacial traits within the context of sex and locate several regions of the genome that contribute to variation in craniofacial shape that is relevant to sexual dimorphism within species and subtle divergence between closely related species, and possibly to craniofacial divergence in the Malawi radiation as a whole. To enhance our search for candidate genes we take advantage of population genomic data and a genetic map that is anchored to the cichlid genome to determine which genes within our QTL regions are associated with SNPs that are alternatively fixed between species. This study provides a holistic understanding of the genetic underpinnings of adaptive divergence in craniofacial shape. PMID:26038365

  12. Artisticc: An Art and Science Integration Project to Enquire into Community Level Adaptation to Climate Change

    NASA Astrophysics Data System (ADS)

    Vanderlinden, J. P.; Baztan, J.

    2014-12-01

    The prupose of this paper is to present the "Adaptation Research a Transdisciplinary community and policy centered appoach" (ARTisticc) project. ARTisticc's goal is to apply innovative standardized transdisciplinary art and science integrative approaches to foster robust, socially, culturally and scientifically, community centred adaptation to climate change. The approach used in the project is based on the strong understanding that adaptation is: (a) still "a concept of uncertain form"; (b) a concept dealing with uncertainty; (c) a concept that calls for an analysis that goes beyond the traditional disciplinary organization of science, and; (d) an unconventional process in the realm of science and policy integration. The project is centered on case studies in France, Greenland, Russia, India, Canada, Alaska, and Senegal. In every site we jointly develop artwork while we analyzing how natural science, essentially geosciences can be used in order to better adapt in the future, how society adapt to current changes and how memories of past adaptations frames current and future processes. Artforms are mobilized in order to share scientific results with local communities and policy makers, this in a way that respects cultural specificities while empowering stakeholders, ARTISTICC translates these "real life experiments" into stories and artwork that are meaningful to those affected by climate change. The scientific results and the culturally mediated productions will thereafter be used in order to co-construct, with NGOs and policy makers, policy briefs, i.e. robust and scientifically legitimate policy recommendations regarding coastal adaptation. This co-construction process will be in itself analysed with the goal of increasing arts and science's performative functions in the universe of evidence-based policy making. The project involves scientists from natural sciences, the social sciences and the humanities, as well as artitis from the performing arts (playwriters

  13. Ecological genomics meets community-level modelling of biodiversity: mapping the genomic landscape of current and future environmental adaptation.

    PubMed

    Fitzpatrick, Matthew C; Keller, Stephen R

    2015-01-01

    Local adaptation is a central feature of most species occupying spatially heterogeneous environments, and may factor critically in responses to environmental change. However, most efforts to model the response of species to climate change ignore intraspecific variation due to local adaptation. Here, we present a new perspective on spatial modelling of organism-environment relationships that combines genomic data and community-level modelling to develop scenarios regarding the geographic distribution of genomic variation in response to environmental change. Rather than modelling species within communities, we use these techniques to model large numbers of loci across genomes. Using balsam poplar (Populus balsamifera) as a case study, we demonstrate how our framework can accommodate nonlinear responses of loci to environmental gradients. We identify a threshold response to temperature in the circadian clock gene GIGANTEA-5 (GI5), suggesting that this gene has experienced strong local adaptation to temperature. We also demonstrate how these methods can map ecological adaptation from genomic data, including the identification of predicted differences in the genetic composition of populations under current and future climates. Community-level modelling of genomic variation represents an important advance in landscape genomics and spatial modelling of biodiversity that moves beyond species-level assessments of climate change vulnerability. PMID:25270536

  14. Noncommutative Chern-Simons theory and exotic geometry emerging from the lowest Landau level

    NASA Astrophysics Data System (ADS)

    Luo, Xi; Wu, Yong-Shi; Yu, Yue

    2016-06-01

    We relate the collective dynamic internal geometric degrees of freedom to the gauge fluctuations in ν =1 /m (m odd ) fractional quantum Hall effects. In this way, in the lowest Landau level, a highly nontrivial quantum geometry in two-dimensional guiding center space emerges from these internal geometric modes. Using the Dirac bracket method, we find that this quantum geometric field theory is a topological noncommutative Chern-Simons theory. Topological indices, such as the guiding center angular momentum (also called the shift) and the guiding center spin, which characterize the fractional quantum Hall (FQH) states besides the filling factor, are naturally defined. A noncommutative K-matrix Chern-Simons theory is proposed as a generalization to a large class of Abelian FQH topological orders.

  15. The Process of Adaptation of a Community-Level, Evidence-Based Intervention for HIV-Positive African American Men Who Have Sex with Men in Two Cities

    ERIC Educational Resources Information Center

    Robinson, Beatrice E.; Galbraith, Jennifer S.; Lund, Sharon M.; Hamilton, Autumn R.; Shankle, Michael D.

    2012-01-01

    We describe the process of adapting a community-level, evidence-based behavioral intervention (EBI), Community PROMISE, for HIV-positive African American men who have sex with men (AAMSM). The Centers for Disease Control and Prevention (CDC) Map of the Adaptation Process (MAP) guided the adaptation process for this new target population by two…

  16. Grounding Cognitive-Level Processes in Behavior: The View from Dynamic Systems Theory

    PubMed Central

    Samuelson, Larissa K.; Jenkins, Gavin W.; Spencer, John P.

    2015-01-01

    Marr’s seminal work laid out a program of research by specifying key questions for cognitive science at different levels of analysis. Because Dynamic Systems Theory focuses on time and interdependence of components DST research programs come to very different conclusions regarding the nature of cognitive change. We review a specific DST approach to cognitive-level processes: Dynamic Field Theory. We review research applying dynamic field theory to several cognitive-level processes: object permanence, naming hierarchical categories, and inferring intent, that demonstrate the difference in understanding of behavior and cognition that results from a DST perspective. These point to a central challenge for cognitive science research as defined by Marr—emergence. We argue that appreciating emergence raises questions about the utility of computational level analyses and opens the door to insights concerning the origin of novel forms of behavior and thought (e.g., a new chess strategy). We contend this is one of the most fundamental questions about cognition and behavior. PMID:25755203

  17. Adaptive regulation of human intestinal thiamine uptake by extracellular substrate level: a role for THTR-2 transcriptional regulation

    PubMed Central

    Nabokina, Svetlana M.; Subramanian, Veedamali S.; Valle, Judith E.

    2013-01-01

    The intestinal thiamine uptake process is adaptively regulated by the level of vitamin in the diet, but the molecular mechanism involved is not fully understood. Here we used the human intestinal epithelial Caco-2 cells exposed to different levels of extracellular thiamine to delineate the molecular mechanism involved. Our results showed that maintaining Caco-2 cells in a thiamine-deficient medium resulted in a specific and significant increase of [3H]thiamine uptake compared with cell exposure to a high level of thiamine (1 mM). This adaptive regulation was also associated with a higher level of mRNA expression of thiamine transporter-2 (THTR-2), but not thiamine transporter-1 (THTR-1), in the deficient condition and a higher level of promoter activity of gene encoding THTR-2 (SLC19A3). Using 5′-truncated promoter-luciferase constructs, we identified the thiamine level-responsive region in the SLC19A3 promoter to be between −77 and −29 (using transcriptional start site as +1). By means of mutational analysis, a key role for a stimulating protein-1 (SP1)/guanosine cytidine box in mediating the effect of extracellular thiamine level on SLC19A3 promoter was established. Furthermore, extracellular level of thiamine was found to affect SP1 protein expression and binding pattern to the thiamine level-responsive region of SLC19A3 promoter in Caco-2 cells as shown by Western blotting and electrophoretic mobility shift assay analysis, respectively. These studies demonstrate that the human intestinal thiamine uptake is adaptively regulated by the extracellular substrate level via transcriptional regulation of the THTR-2 system, and report that SP1 transcriptional factor is involved in this regulation. PMID:23989004

  18. Adapting portfolio theory for the evaluation of multiple investments in health with a multiplicative extension for treatment synergies.

    PubMed

    Bridges, J F P; Stewart, M; King, M T; van Gool, K

    2002-01-01

    Portfolio theory is central to the analysis of risk in many areas of economics but is seldom used appropriately in health economics. This contribution examines the use of portfolio theory in the context of cost-effectiveness analysis (CEA). A number of modifications are needed to apply portfolio analysis to the economic evaluation of health care interventions. First, the method of reporting the results of a CEA, and consequently some of the underlying assumptions, needs to be modified. Second, portfolio theory needs to be expressed in terms of effects on individuals aggregated to a population. Finally, one needs to allow for the possibility of synergy between the various health interventions. This paper derives a general formula for a portfolio of health care interventions that allows for synergies between interventions where the population effects are aggregated from individual effects. A number of special cases are also derived to highlight the nature of the formulation of the modified portfolio theory. We conclude that, while modified portfolio theory adds a theoretical foundation to health care evaluations, it may not be operational until estimates of the correlation between interventions are available, and the question of uncertainty is resolved in health care evaluation. Also, while a synergy may be present at the individual level, when aggregated over a large population it may not be significant given the standard assumption of constant returns to scale. PMID:15609117

  19. Translation of HLA-HIV associations to the cellular level: HIV adapts to inflate CD8 T cell responses against Nef and HLA-adapted variant epitopes.

    PubMed

    Almeida, Coral-Ann M; Bronke, Corine; Roberts, Steven G; McKinnon, Elizabeth; Keane, Niamh M; Chopra, Abha; Kadie, Carl; Carlson, Jonathan; Haas, David W; Riddler, Sharon A; Haubrich, Richard; Heckerman, David; Mallal, Simon; John, Mina

    2011-09-01

    Strong statistical associations between polymorphisms in HIV-1 population sequences and carriage of HLA class I alleles have been widely used to identify possible sites of CD8 T cell immune selection in vivo. However, there have been few attempts to prospectively and systematically test these genetic hypotheses arising from population-based studies at a cellular, functional level. We assayed CD8 T cell epitope-specific IFN-γ responses in 290 individuals from the same cohort, which gave rise to 874 HLA-HIV associations in genetic analyses, taking into account autologous viral sequences and individual HLA genotypes. We found immunological evidence for 58% of 374 associations tested as sites of primary immune selection and identified up to 50 novel HIV-1 epitopes using this reverse-genomics approach. Many HLA-adapted epitopes elicited equivalent or higher-magnitude IFN-γ responses than did the nonadapted epitopes, particularly in Nef. At a population level, inclusion of all of the immunoreactive variant CD8 T cell epitopes in Gag, Pol, Nef, and Env suggested that HIV adaptation leads to an inflation of Nef-directed immune responses relative to other proteins. We concluded that HLA-HIV associations mark viral epitopes subject to CD8 T cell selection. These results can be used to guide functional studies of specific epitopes and escape mutations, as well as to test, train, and evaluate analytical models of viral escape and fitness. The inflation of Nef and HLA-adapted variant responses may have negative effects on natural and vaccine immunity against HIV and, therefore, has implications for diversity coverage approaches in HIV vaccine design. PMID:21821798

  20. Evidence-based decision-making in healthcare: exploring the issues though the lens of complex, adaptive systems theory.

    PubMed

    Lindstrom, Ronald R

    2003-01-01

    Browman, Snider and Ellis have articulated several reasons as to why and how managers should address the implementation of evidence-based decision-making (EBDM) in healthcare. While their observations are acknowledged to be from the unique perspective of an oncology setting, this is a timely and welcome lead article with significance in other settings. The authors invite opinions on transferability, thus forming the basis of this commentary. In response, this commentary offers a number of supportive and differing views. Complex, adaptive systems (CAS) theory is first addressed as an appropriate lens to reframe our conceptualization of the health system. Then, in contrast to negotiation, dialogue through participatory planning and decision-making is introduced. Evidence-based decision-making (EBDM) and knowledge translation (KT) are expanded upon in the context of CAS and participatory environments. Finally, concrete suggestions are offered on how to structure multiple-stakeholder involvement in the decision-making process, including the growing role of consumers in the new complex, adaptive systems reality of healthcare. PMID:12811085

  1. Integrative curriculum reform, domain dependent knowing, and teachers` epistemological theories: Implications for middle-level teaching

    SciTech Connect

    Powell, R.R.

    1998-12-01

    Integrative curriculum as both a theoretical construct and a practical reality, and as a theme-based, problem-centered, democratic way of schooling, is becoming more widely considered as a feasible alternative to traditional middle-level curricula. Importantly for teaching and learning, domain dependence requires teachers to view one area of knowledge as fully interdependent with other areas of knowledge during the learning process. This requires teachers to adopt personal epistemological theories that reflect integrative, domain dependent knowing. This study explored what happened when teachers from highly traditional domain independent school settings encountered an ambitious college-level curriculum project that was designed to help the teachers understand the potential that integrative, domain dependent teaching holds for precollege settings. This study asked: What influence does an integrative, domain dependent curriculum project have on teachers` domain independent, epistemological theories for teaching and learning? Finding an answer to this question is essential if we, as an educational community, are to understand how integrative curriculum theory is transformed by teachers into systemic curriculum reform. The results suggest that the integrative curriculum project that teachers participated in did not explicitly alter their classroom practices in a wholesale manner. Personal epistemological theories of teachers collectively precluded teachers from making any wholesale changes in their individual classroom teaching. However, teachers became aware of integrative curriculum as an alternative, and they expressed interest in infusing integrative practices into their classrooms as opportunities arise.

  2. Cortico-hippocampal interaction and adaptive stimulus representation: a neurocomputational theory of associative learning and memory.

    PubMed

    Gluck, Mark A; Myers, Catherine; Meeter, Martijn

    2005-11-01

    Computational models of the hippocampal region link psychological theories of associative learning with their underlying physiological and anatomical substrates. Our approach to theory development began with a broad description of the computations that depend on the hippocampal region in classical conditioning (Gluck and Myers, 1993 and Gluck and Myers, 2001). In this initial model, the hippocampal region was treated as an Information-processing system that transformed stimulus representations, compressing (making more similar) representations of inputs that co-occur or are otherwise redundant, while differentiating (or making less similar) representations of inputs that predict different future events. This model led to novel predictions for the behavioral consequences of hippocampal-region lesions in rodents and of brain damage in humans who have amnesia or are in the earliest stages of Alzheimer's disease. Many of these predictions have, since been confirmed by our lab and others. Functional brain imaging studies have provided further supporting evidence. In more recent computational modeling, we have shown how some aspects of this proposed information-processing function could emerge from known anatomical and physiological characteristics of the hippocampal region, including the entorhinal cortex and the septo-hippocampal cholinergic system. The modeling to date lays the groundwork for future directions that increase the depth of detail of the biological modeling, as well as the breadth of behavioral phenomena addressed. In particular, we are working now to reconcile these kinds of incremental associative learning models with other models of the hippocampal region that account for the rapid formation of declarative memories. PMID:16275027

  3. COREDAR: COmmunicating Risk of sea level rise and Engaging stakeholDers in framing community based Adaptation stRategies

    NASA Astrophysics Data System (ADS)

    Amsad Ibrahim Khan, S. K.; Chen, R. S.; de Sherbinin, A. M.; Andimuthu, R.; Kandasamy, P.

    2015-12-01

    Accelerated sea-level rise (SLR) is a major long term outcome of climate change leading to increased inundation of low-lying areas. Particularly, global cities that are located on or near the coasts are often situated in low lying areas and these locations put global cities at greater risk to SLR. Localized flooding will profoundly impact vulnerable communities located in high-risk urban areas. Building community resilience and adapting to SLR is increasingly a high priority for cities. On the other hand, Article 6 of the United Nations Framework Convention on Climate Change addresses the importance of climate change communication and engaging stakeholders in decision making process. Importantly, Community Based Adaptation (CBA) experiences emphasize that it is important to understand a community's unique perceptions of their adaptive capacities to identify useful solutions and that scientific and technical information on anticipated coastal climate impacts needs to be translated into a suitable language and format that allows people to be able to participate in adaptation planning. To address this challenge, this study has put forth three research questions from the lens of urban community engagement in SLR adaptation, (1) What, if any, community engagement in addressing SLR occurring in urban areas; (2) What information do communities need and how does it need to be communicated, in order to be better prepared and have a greater sense of agency? and (3) How can government agencies from city to federal levels facilitate community engagement and action?. To answer these questions this study has evolved a framework "COREDAR" (COmmunicating Risk of sea level rise and Engaging stakeholDers in framing community based Adaptation StRategies) to communicate and transfer complex climate data and information such as projected SLR under different scenarios of IPCC AR5, predicted impact of SLR, prioritizing vulnerability, etc. to concerned stakeholders and local communities

  4. A Study On The Effect Of Multiple Intelligences Theory Upon The Success Level Of Genders

    NASA Astrophysics Data System (ADS)

    Oral, Imran

    2007-04-01

    In this study, the effects of Multiple Intelligences theory upon the success level of genders were investigated at three high schools in Konya. In conclusion, a significant difference has not been found between groups for multiple intelligences and groups for pre-tests. In general, the female student groups were more successful than the male student groups regarding post-test. However, this result did not cause a significant difference between the groups.

  5. Leveling the Playing Field: Adapted PE Brings Together Kids with and without Disabilities.

    ERIC Educational Resources Information Center

    Jarrett, Denise

    2000-01-01

    Adapted physical education (APE) makes whatever adjustments are needed to allow students with disabilities to participate in regular physical education classes. APE at Beaverton School District (Oregon) is described, as well as the individualized special physical education classes provided to children with severe disabilities. (SV)

  6. Phase transitions in adaptive competitive environments: Theories and applications of the minority game

    NASA Astrophysics Data System (ADS)

    Li, Yi

    It is of great scientific significance to study the complex systems of agents with adaptive strategies competing for resources. In many of such systems in social and biological environments, agents succeed by making innovative choices. In this thesis, we model this behavior by presenting the results and analysis of a class of games in which heterogeneous agents are rewarded for being in a minority group. Each agent possesses a number of fixed strategies, each of which takes publicly available information as input to predict next group. Commonly known as the minority game, this simple model manifests a maladaptive, informationally efficient phase in which the system performs poorly at generating resources and an inefficient phase in which there is an emergent cooperation among the agents, and the system more effectively generates resources. The best emergent coordination is achieved at the phase transition, which occurs when z, the ratio of the dimension of the strategy space to the number of agents, is about 0.34. This model also has similar properties to a spin glass system thus statistical mechanics methods were employed to provide analytical results. The phase structure persists under variations such as variable payoff schemes and evolutionary mechanisms. Agents in real life are subject to local connectivity and incomplete information. A framework based on bi-graph was proposed to model these factors. In the context of economics, we proposed a stock market model incorporating delayed majority dynamics and agents holding heterogeneous expectations. We found that for a range of parameter settings, minority dynamics are dynamically induced, effectively reducing market volatility. Finally, we introduce a version of the minority game played by human participants. We observed emergent coordination of players' choices leading to increased average reward. Furthermore, players with the simplest strategies reap the most wealth.

  7. Electron-impact excitation of the n 1P levels of helium - Theory and experiment

    NASA Technical Reports Server (NTRS)

    Cartwright, David C.; Csanak, George; Trajmar, Sandor; Register, D. F.

    1992-01-01

    New experimental electron-energy-loss data have been used to extract differential and integral cross sections for excitation of the 2 1P level, and for the overlapping (3 1P, 3 1D, 3 3D) levels of helium, at 30-, 50-, and 100-eV incident electron energies. First-order many-body theory (FOMBT) has been used to calculate the differential and integral cross sections for excitation of the n 1P (n = 2,...,6) levels of helium by electron impact, for incident electron energies from threshold to 500 eV. Detailed comparisons between these two new sets of data are made as well as comparisons with appropriate published experimental and theoretical results. A simple scaling relationship is derived from the FOMBT results for n = 2,...,6 that provides differential and integral cross sections for all symmetry final levels of helium with n = 6 or greater.

  8. Biologically inspired information theory: Adaptation through construction of external reality models by living systems.

    PubMed

    Nakajima, Toshiyuki

    2015-12-01

    Higher animals act in the world using their external reality models to cope with the uncertain environment. Organisms that have not developed such information-processing organs may also have external reality models built in the form of their biochemical, physiological, and behavioral structures, acquired by natural selection through successful models constructed internally. Organisms subject to illusions would fail to survive in the material universe. How can organisms, or living systems in general, determine the external reality from within? This paper starts with a phenomenological model, in which the self constitutes a reality model developed through the mental processing of phenomena. Then, the it-from-bit concept is formalized using a simple mathematical model. For this formalization, my previous work on an algorithmic process is employed to constitute symbols referring to the external reality, called the inverse causality, with additional improvements to the previous work. Finally, as an extension of this model, the cognizers system model is employed to describe the self as one of many material entities in a world, each of which acts as a subject by responding to the surrounding entities. This model is used to propose a conceptual framework of information theory that can deal with both the qualitative (semantic) and quantitative aspects of the information involved in biological processes. PMID:26196087

  9. Grounding cognitive-level processes in behavior: the view from dynamic systems theory.

    PubMed

    Samuelson, Larissa K; Jenkins, Gavin W; Spencer, John P

    2015-04-01

    Marr's seminal work laid out a program of research by specifying key questions for cognitive science at different levels of analysis. Because dynamic systems theory (DST) focuses on time and interdependence of components, DST research programs come to very different conclusions regarding the nature of cognitive change. We review a specific DST approach to cognitive-level processes: dynamic field theory (DFT). We review research applying DFT to several cognitive-level processes: object permanence, naming hierarchical categories, and inferring intent, that demonstrate the difference in understanding of behavior and cognition that results from a DST perspective. These point to a central challenge for cognitive science research as defined by Marr-emergence. We argue that appreciating emergence raises questions about the utility of computational-level analyses and opens the door to insights concerning the origin of novel forms of behavior and thought (e.g., a new chess strategy). We contend this is one of the most fundamental questions about cognition and behavior. PMID:25755203

  10. Several high speed multiplier theory for low-light-level technology

    NASA Astrophysics Data System (ADS)

    Li, Xiancang; Zhang, Liuqiang; Xiao, Haijun; Zhao, Jun

    2013-08-01

    Low-light-level image intensifier images weak optical signal through electron multiplication process in Low-light-level night vision device, the key technology of intensifier is electron multiplier, the thesis put forward three kinds of electron multiplication methods. One is that the electron multiplier device is the avalanche transistor made use of the semiconductor material, the thesis analyses the photoelectric conversion theory and rapid multiplication avalanche breakdown conditions with PN junction of the avalanche diode under reverse bias by light excitation; the second approach is to use gas discharge theory to explains the electron multiplication process in the low-pressure gas and high-pressure gas discharging breakdown by photon excitation; the third method is photoelectron multiplication gain theory,in the microchannel plate (MCP) as the second generation image intensifier in vacuum condition and the applied voltage. The thesis analyses that the electronic gain efficiency is better than the other two methods ,and proposes the avalanche transistor can be key device of image intensifier.

  11. Uncertainty Propagation and Quantification using Constrained Coupled Adaptive Forward-Inverse Schemes: Theory and Applications

    NASA Astrophysics Data System (ADS)

    Ryerson, F. J.; Ezzedine, S. M.; Antoun, T.

    2013-12-01

    equation for the distribution of k is solved, provided that Cauchy data are appropriately assigned. In the next stage, only a limited number of passive measurements are provided. In this case, the forward and inverse PDEs are solved simultaneously. This is accomplished by adding regularization terms and filtering the pressure gradients in the inverse problem. Both the forward and the inverse problem are either simultaneously or sequentially coupled and solved using implicit schemes, adaptive mesh refinement, Galerkin finite elements. The final case arises when P, k, and Q data only exist at producing wells. This exceedingly ill posed problem calls for additional constraints on the forward-inverse coupling to insure that the production rates are satisfied at the desired locations. Results from all three cases are presented demonstrating stability and accuracy of the proposed approach and, more importantly, providing some insights into the consequences of data under sampling, uncertainty propagation and quantification. We illustrate the advantages of this novel approach over the common UQ forward drivers on several subsurface energy problems in either porous or fractured or/and faulted reservoirs. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  12. Constraints on Tree-Level Higher Order Gravitational Couplings in Superstring Theory

    SciTech Connect

    Stieberger, Stephan

    2011-03-18

    We consider the scattering amplitudes of five and six gravitons at tree level in superstring theory. Their power series expansions in the Regge slope {alpha}{sup '} are analyzed through the order {alpha}{sup '8} showing some interesting constraints on higher order gravitational couplings in the effective superstring action such as the absence of R{sup 5} terms. Furthermore, some transcendentality constraints on the coefficients of the nonvanishing couplings are observed: the absence of zeta values of even weight through the order {alpha}{sup '8} like the absence of {zeta}(2){zeta}(3)R{sup 6} terms. Our analysis is valid for any superstring background in any space-time dimension, which allows for a conformal field theory description.

  13. Constraints on tree-level higher order gravitational couplings in superstring theory.

    PubMed

    Stieberger, Stephan

    2011-03-18

    We consider the scattering amplitudes of five and six gravitons at tree level in superstring theory. Their power series expansions in the Regge slope α' are analyzed through the order α'(8) showing some interesting constraints on higher order gravitational couplings in the effective superstring action such as the absence of R(5) terms. Furthermore, some transcendentality constraints on the coefficients of the nonvanishing couplings are observed: the absence of zeta values of even weight through the order α'(8) like the absence of ζ(2)ζ(3)R(6) terms. Our analysis is valid for any superstring background in any space-time dimension, which allows for a conformal field theory description. PMID:21469856

  14. Multi-valley effective mass theory for device-level modeling of open quantum dynamics

    NASA Astrophysics Data System (ADS)

    Jacobson, N. Tobias; Baczewski, Andrew D.; Frees, Adam; Gamble, John King; Montano, Ines; Moussa, Jonathan E.; Muller, Richard P.; Nielsen, Erik

    2015-03-01

    Simple models for semiconductor-based quantum information processors can provide useful qualitative descriptions of device behavior. However, as experimental implementations have matured, more specific guidance from theory has become necessary, particularly in the form of quantitatively reliable yet computationally efficient modeling. Besides modeling static device properties, improved characterization of noisy gate operations requires a more sophisticated description of device dynamics. Making use of recent developments in multi-valley effective mass theory, we discuss device-level simulations of the open system quantum dynamics of a qubit interacting with phonons and other noise sources. Sandia is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy National Nuclear Security Administration under Contract No. DE-AC04-94AL85000.

  15. Hyperspectral target detection using graph theory models and manifold geometry via an adaptive implementation of locally linear embedding

    NASA Astrophysics Data System (ADS)

    Ziemann, Amanda K.; Messinger, David W.

    2014-06-01

    Hyperspectral images comprise, by design, high dimensional image data. However, research has shown that for a d-dimensional hyperspectral image, it is typical for the data to inherently occupy an m-dimensional space, with m << d. In the remote sensing community, this has led to a recent increase in the use of non-linear manifold learning, which aims to characterize the embedded lower-dimensional, non-linear manifold upon which the hyperspectral data inherently lie. Classic hyperspectral data models include statistical, linear subspace, and linear mixture models, but these can place restrictive assumptions on the distribution of the data. With graph theory and manifold learning based models, the only assumption is that the data reside on an underlying manifold. In previous publications, we have shown that manifold coordinate approximation using locally linear embedding (LLE) is a viable pre-processing step for target detection with the Adaptive Cosine/Coherence Estimator (ACE) algorithm. Here, we improve upon that methodology using a more rigorous, data-driven implementation of LLE that incorporates the injection of a cloud" of target pixels and the Spectral Angle Mapper (SAM) detector. The LLE algorithm, which holds that the data is locally linear, is typically governed by a user defined parameter k, indicating the number of nearest neighbors to use in the initial graph model. We use an adaptive approach to building the graph that is governed by the data itself and does not rely upon user input. This implementation of LLE can yield greater separation between the target pixels and the background pixels in the manifold space. We present an analysis of target detection performance in the manifold coordinates using scene-derived target spectra and laboratory-measured target spectra across two different data sets.

  16. Development of a Computerized Adaptive Testing for Diagnosing the Cognitive Process of Grade 7 Students in Learning Algebra, Using Multidimensional Item Response Theory

    ERIC Educational Resources Information Center

    Senarat, Somprasong; Tayraukham, Sombat; Piyapimonsit, Chatsiri; Tongkhambanjong, Sakesan

    2013-01-01

    The purpose of this research is to develop a multidimensional computerized adaptive test for diagnosing the cognitive process of grade 7 students in learning algebra by applying multidimensional item response theory. The research is divided into 4 steps: 1) the development of item bank of algebra, 2) the development of the multidimensional…

  17. An Item Response Theory-Based, Computerized Adaptive Testing Version of the MacArthur-Bates Communicative Development Inventory: Words & Sentences (CDI:WS)

    ERIC Educational Resources Information Center

    Makransky, Guido; Dale, Philip S.; Havmose, Philip; Bleses, Dorthe

    2016-01-01

    Purpose: This study investigated the feasibility and potential validity of an item response theory (IRT)-based computerized adaptive testing (CAT) version of the MacArthur-Bates Communicative Development Inventory: Words & Sentences (CDI:WS; Fenson et al., 2007) vocabulary checklist, with the objective of reducing length while maintaining…

  18. Credibility theory based dynamic control bound optimization for reservoir flood limited water level

    NASA Astrophysics Data System (ADS)

    Jiang, Zhiqiang; Sun, Ping; Ji, Changming; Zhou, Jianzhong

    2015-10-01

    The dynamic control operation of reservoir flood limited water level (FLWL) can solve the contradictions between reservoir flood control and beneficial operation well, and it is an important measure to make sure the security of flood control and realize the flood utilization. The dynamic control bound of FLWL is a fundamental key element for implementing reservoir dynamic control operation. In order to optimize the dynamic control bound of FLWL by considering flood forecasting error, this paper took the forecasting error as a fuzzy variable, and described it with the emerging credibility theory in recent years. By combining the flood forecasting error quantitative model, a credibility-based fuzzy chance constrained model used to optimize the dynamic control bound was proposed in this paper, and fuzzy simulation technology was used to solve the model. The FENGTAN reservoir in China was selected as a case study, and the results show that, compared with the original operation water level, the initial operation water level (IOWL) of FENGTAN reservoir can be raised 4 m, 2 m and 5.5 m respectively in the three division stages of flood season, and without increasing flood control risk. In addition, the rationality and feasibility of the proposed forecasting error quantitative model and credibility-based dynamic control bound optimization model are verified by the calculation results of extreme risk theory.

  19. Exploration of zeroth-order wavefunctions and energies as a first step toward intramolecular symmetry-adapted perturbation theory

    NASA Astrophysics Data System (ADS)

    Gonthier, Jérôme F.; Corminboeuf, Clémence

    2014-04-01

    Non-covalent interactions occur between and within all molecules and have a profound impact on structural and electronic phenomena in chemistry, biology, and material science. Understanding the nature of inter- and intramolecular interactions is essential not only for establishing the relation between structure and properties, but also for facilitating the rational design of molecules with targeted properties. These objectives have motivated the development of theoretical schemes decomposing intermolecular interactions into physically meaningful terms. Among the various existing energy decomposition schemes, Symmetry-Adapted Perturbation Theory (SAPT) is one of the most successful as it naturally decomposes the interaction energy into physical and intuitive terms. Unfortunately, analogous approaches for intramolecular energies are theoretically highly challenging and virtually nonexistent. Here, we introduce a zeroth-order wavefunction and energy, which represent the first step toward the development of an intramolecular variant of the SAPT formalism. The proposed energy expression is based on the Chemical Hamiltonian Approach (CHA), which relies upon an asymmetric interpretation of the electronic integrals. The orbitals are optimized with a non-hermitian Fock matrix based on two variants: one using orbitals strictly localized on individual fragments and the other using canonical (delocalized) orbitals. The zeroth-order wavefunction and energy expression are validated on a series of prototypical systems. The computed intramolecular interaction energies demonstrate that our approach combining the CHA with strictly localized orbitals achieves reasonable interaction energies and basis set dependence in addition to producing intuitive energy trends. Our zeroth-order wavefunction is the primary step fundamental to the derivation of any perturbation theory correction, which has the potential to truly transform our understanding and quantification of non

  20. Exploration of zeroth-order wavefunctions and energies as a first step toward intramolecular symmetry-adapted perturbation theory

    SciTech Connect

    Gonthier, Jérôme F.; Corminboeuf, Clémence

    2014-04-21

    Non-covalent interactions occur between and within all molecules and have a profound impact on structural and electronic phenomena in chemistry, biology, and material science. Understanding the nature of inter- and intramolecular interactions is essential not only for establishing the relation between structure and properties, but also for facilitating the rational design of molecules with targeted properties. These objectives have motivated the development of theoretical schemes decomposing intermolecular interactions into physically meaningful terms. Among the various existing energy decomposition schemes, Symmetry-Adapted Perturbation Theory (SAPT) is one of the most successful as it naturally decomposes the interaction energy into physical and intuitive terms. Unfortunately, analogous approaches for intramolecular energies are theoretically highly challenging and virtually nonexistent. Here, we introduce a zeroth-order wavefunction and energy, which represent the first step toward the development of an intramolecular variant of the SAPT formalism. The proposed energy expression is based on the Chemical Hamiltonian Approach (CHA), which relies upon an asymmetric interpretation of the electronic integrals. The orbitals are optimized with a non-hermitian Fock matrix based on two variants: one using orbitals strictly localized on individual fragments and the other using canonical (delocalized) orbitals. The zeroth-order wavefunction and energy expression are validated on a series of prototypical systems. The computed intramolecular interaction energies demonstrate that our approach combining the CHA with strictly localized orbitals achieves reasonable interaction energies and basis set dependence in addition to producing intuitive energy trends. Our zeroth-order wavefunction is the primary step fundamental to the derivation of any perturbation theory correction, which has the potential to truly transform our understanding and quantification of non

  1. Multichannel-quantum-defect-theory treatment of preionized and predissociated triplet gerade levels of H2

    NASA Astrophysics Data System (ADS)

    Matzkin, A.; Jungen, Ch.; Ross, S. C.

    2000-12-01

    Multichannel quantum defect theory (MQDT) is used to calculate highly excited predissociated and preionized triplet gerade states of H2. The treatment is ab initio and is based on the clamped-nuclei quantum-defect matrices and dipole transition moments derived from quantum-chemical potential energy curves by Ross et al. [Can. J. Phys. (to be published)]. Level positions, predissociation or preionization widths and relative intensities are found to be in good agreement with those observed by Lembo et al. [Phys. Rev. A 38, 3447 (1988); J. Chem. Phys. 92, 2219 (1990)] by an optical-optical double resonance photoionization or depletion technique.

  2. Reliable Energy Level Alignment at Physisorbed Molecule–Metal Interfaces from Density Functional Theory

    PubMed Central

    2015-01-01

    A key quantity for molecule–metal interfaces is the energy level alignment of molecular electronic states with the metallic Fermi level. We develop and apply an efficient theoretical method, based on density functional theory (DFT) that can yield quantitatively accurate energy level alignment information for physisorbed metal–molecule interfaces. The method builds on the “DFT+Σ” approach, grounded in many-body perturbation theory, which introduces an approximate electron self-energy that corrects the level alignment obtained from conventional DFT for missing exchange and correlation effects associated with the gas-phase molecule and substrate polarization. Here, we extend the DFT+Σ approach in two important ways: first, we employ optimally tuned range-separated hybrid functionals to compute the gas-phase term, rather than rely on GW or total energy differences as in prior work; second, we use a nonclassical DFT-determined image-charge plane of the metallic surface to compute the substrate polarization term, rather than the classical DFT-derived image plane used previously. We validate this new approach by a detailed comparison with experimental and theoretical reference data for several prototypical molecule–metal interfaces, where excellent agreement with experiment is achieved: benzene on graphite (0001), and 1,4-benzenediamine, Cu-phthalocyanine, and 3,4,9,10-perylene-tetracarboxylic-dianhydride on Au(111). In particular, we show that the method correctly captures level alignment trends across chemical systems and that it retains its accuracy even for molecules for which conventional DFT suffers from severe self-interaction errors. PMID:25741626

  3. Evolution of cooperation facilitated by reinforcement learning with adaptive aspiration levels.

    PubMed

    Tanabe, Shoma; Masuda, Naoki

    2012-01-21

    Repeated interaction between individuals is the main mechanism for maintaining cooperation in social dilemma situations. Variants of tit-for-tat (repeating the previous action of the opponent) and the win-stay lose-shift strategy are known as strong competitors in iterated social dilemma games. On the other hand, real repeated interaction generally allows plasticity (i.e., learning) of individuals based on the experience of the past. Although plasticity is relevant to various biological phenomena, its role in repeated social dilemma games is relatively unexplored. In particular, if experience-based learning plays a key role in promotion and maintenance of cooperation, learners should evolve in the contest with nonlearners under selection pressure. By modeling players using a simple reinforcement learning model, we numerically show that learning enables the evolution of cooperation. We also show that numerically estimated adaptive dynamics appositely predict the outcome of evolutionary simulations. The analysis of the adaptive dynamics enables us to capture the obtained results as an affirmative example of the Baldwin effect, where learning accelerates the evolution to optimality. PMID:22037063

  4. Explaining fruit and vegetable consumption: the theory of planned behaviour and misconception of personal intake levels.

    PubMed

    Bogers, R P; Brug, J; van Assema, P; Dagnelie, P C

    2004-04-01

    The influence of individuals' misconceptions in assessing fruit and vegetable consumption on the ability of the theory of planned behaviour to explain variance in the consumption of these foods was studied. Dutch women (mean age 41, n=159) completed a questionnaire assessing the theory's constructs with regard to the daily consumption of at least two pieces of fruit and 200 gram of vegetables. Consumption was assessed using a self-rated measure and more objectively with a food-frequency questionnaire. Both measures were combined to classify participants according to the accuracy of their self-assessed intake levels ('realists' vs. 'overestimators'). The model explained variation in objective fruit and vegetable intake much better among realists (R2 = 45% for fruits and 39% for vegetables) than among overestimators (R2 = 18% and 5%, respectively). Perceived behavioural control was the strongest predictor of intentions and behaviour. When plasma vitamin C and carotenoid concentrations were used as objective indicators for fruit and vegetable intake, the explanatory value of the model was lower, but again more variance was explained among realists than among overestimators. We conclude that awareness of personal behaviour should be taken into account when applying the theory of planned behaviour to explain dietary behaviours as well as to design health education interventions. PMID:15010180

  5. Toward a Physically Motivated Force Field: Hydrogen Bond Directionality from a Symmetry-Adapted Perturbation Theory Perspective.

    PubMed

    Tafipolsky, Maxim; Ansorg, Kay

    2016-03-01

    It is argued here that the functional forms adopted in almost all popular force fields are too restrictive to allow for accurate and physics-based parametrization. Some important modifications are suggested based on symmetry-adapted intermolecular perturbation theory, which directly separates the intermolecular interaction energy into four physically interpretable components: electrostatics, exchange-repulsion, dispersion, and induction. The exact electrostatic energy is approximated as a sum of the short-range contribution (due to charge density penetration effects), included explicitly, and the long-range part (via distributed atomic multipoles), whereas the induction energy is evaluated by means of the distributed induced damped point dipole model. The dispersion energy is fitted to a simple analytical function and the exchange-repulsion contribution is approximated by the overlap of the valence-only electron charge densities of monomers. The water dimer is used to illustrate the approach and to discuss its potential and possible improvements. Analysis of the four main contributions to the binding energy allows for a deeper understanding of the hydrogen bond directionality. It is found that a notorious geometrical preference in the water dimer results mainly from large polarization contributions, including induction and dispersion. PMID:26820162

  6. Semianalytic theory of self-similar optical propagation and mode locking using a shape-adaptive model pulse

    SciTech Connect

    Jirauschek, Christian; Ilday, F. Oemer

    2011-06-15

    A semianalytic theory for the pulse dynamics in similariton amplifiers and lasers is presented, based on a model pulse with adaptive shape. By changing a single parameter, this test function can be continuously tweaked between a pure Gaussian and a pure parabolic profile and can even represent sech-like pulses, the shape of a soliton. This approach allows us to describe the pulse evolution in the self-similar and other regimes of optical propagation. Employing the method of moments, the evolution equations for the characteristic pulse parameters are derived from the governing nonlinear Schroedinger or Ginzburg-Landau equation. Due to its greatly reduced complexity, this description allows for extensive parameter optimization, and can aid intuitive understanding of the dynamics. As an application of this approach, we model a soliton-similariton laser and validate the results against numerical simulations. This constitutes a semianalytic model of the soliton-similariton laser. Due to the versatility of the model pulse, it can also prove useful in other application areas.

  7. Towards a molecular-level theory of carbohydrate processivity in glycoside hydrolases.

    PubMed

    Beckham, Gregg T; Ståhlberg, Jerry; Knott, Brandon C; Himmel, Michael E; Crowley, Michael F; Sandgren, Mats; Sørlie, Morten; Payne, Christina M

    2014-06-01

    Polysaccharide depolymerization in nature is primarily accomplished by processive glycoside hydrolases (GHs), which abstract single carbohydrate chains from polymer crystals and cleave glycosidic linkages without dissociating after each catalytic event. Understanding the molecular-level features and structural aspects of processivity is of importance due to the prevalence of processive GHs in biomass-degrading enzyme cocktails. Here, we describe recent advances towards the development of a molecular-level theory of processivity for cellulolytic and chitinolytic enzymes, including the development of novel methods for measuring rates of key steps in processive action and insights gained from structural and computational studies. Overall, we present a framework for developing structure-function relationships in processive GHs and outline additional progress towards developing a fundamental understanding of these industrially important enzymes. PMID:24863902

  8. Exploring the cultural adaptability of doctoral entry-level physical therapist students during clinical education experiences.

    PubMed

    Hilliard, Marjorie Johnson; Rathsack, Christi; Brannigan, Pauline; Sander, Antoinette P

    2008-01-01

    Cultural competence is an essential component of health care education. The aim of this study was to explore the development of cultural competence in 14 physical therapist students during their final, 23 weeks of clinical education (CE) experiences. A mixed methods design was used to quantitatively measure and qualitatively describe cultural adaptability as an indicator of cultural competence. Subjects completed the Cross-Cultural Adaptability Inventory (CCAI) at the end of their didactic curriculum and again at the end of their CE experiences. Constant comparative methods were used to analyze written narrative summaries of how students made meaning of their cultural encounters. The students exhibited statistically significant changes in the total CCAI score (paired t-test: p < 0.001), and three CCAI subscales: emotional resilience (paired t-test: p < 0.002), flexibility/openness (paired t-test: p < 0.003), and perceptual acuity (paired t-test: p < 0.001). There was not a statistically significant change in the fourth CCAI subscale, personal autonomy. Qualitatively, four themes emerged that described students' cultural encounters with patients, families, and co-workers: recognizing cultural descriptors; consideration of feelings, values, attitudes and beliefs; effective communication to breakdown barriers; and awareness of strategies for current and future cross-cultural practice. Clinical cultural encounters are important in the progression toward cultural competence in physical therapist students. Changes in attitude appear to be key in effective cultural encounters as students learn to communicate and connect with anyone perceived to be different from them. PMID:19753398

  9. Source Similarity and Social Media Health Messages: Extending Construal Level Theory to Message Sources.

    PubMed

    Young, Rachel

    2015-09-01

    Social media users post messages about health goals and behaviors to online social networks. Compared with more traditional sources of health communication such as physicians or health journalists, peer sources are likely to be perceived as more socially close or similar, which influences how messages are processed. This experimental study uses construal level theory of psychological distance to predict how mediated health messages from peers influence health-related cognition and behavioral intention. Participants were exposed to source cues that identified peer sources as being either highly attitudinally and demographically similar to or different from participants. As predicted by construal level theory, participants who perceived sources of social media health messages as highly similar listed a greater proportion of beliefs about the feasibility of health behaviors and a greater proportion of negative beliefs, while participants who perceived sources as more dissimilar listed a greater proportion of positive beliefs about the health behaviors. Results of the study could be useful in determining how health messages from peers could encourage individuals to set realistic health goals. PMID:26348816

  10. Cross-Cultural Competency Adaptability of Dental Hygiene Educators in Entry Level Dental Hygiene Programs

    ERIC Educational Resources Information Center

    Engeswick, Lynnette Marie

    2011-01-01

    This study was conducted to discover the extent dental hygiene educators in 25 entry-level dental hygiene programs from the Upper Midwest demonstrate Emotional Resilience, Flexibility and Openness, Perceptual Acuity, and Personal Autonomy as they relate to their level of education and multicultural experiences. An additional purpose was to examine…

  11. An efficient, scalable, and adaptable framework for solving generic systems of level-set PDEs

    PubMed Central

    Mosaliganti, Kishore R.; Gelas, Arnaud; Megason, Sean G.

    2013-01-01

    In the last decade, level-set methods have been actively developed for applications in image registration, segmentation, tracking, and reconstruction. However, the development of a wide variety of level-set PDEs and their numerical discretization schemes, coupled with hybrid combinations of PDE terms, stopping criteria, and reinitialization strategies, has created a software logistics problem. In the absence of an integrative design, current toolkits support only specific types of level-set implementations which restrict future algorithm development since extensions require significant code duplication and effort. In the new NIH/NLM Insight Toolkit (ITK) v4 architecture, we implemented a level-set software design that is flexible to different numerical (continuous, discrete, and sparse) and grid representations (point, mesh, and image-based). Given that a generic PDE is a summation of different terms, we used a set of linked containers to which level-set terms can be added or deleted at any point in the evolution process. This container-based approach allows the user to explore and customize terms in the level-set equation at compile-time in a flexible manner. The framework is optimized so that repeated computations of common intensity functions (e.g., gradient and Hessians) across multiple terms is eliminated. The framework further enables the evolution of multiple level-sets for multi-object segmentation and processing of large datasets. For doing so, we restrict level-set domains to subsets of the image domain and use multithreading strategies to process groups of subdomains or level-set functions. Users can also select from a variety of reinitialization policies and stopping criteria. Finally, we developed a visualization framework that shows the evolution of a level-set in real-time to help guide algorithm development and parameter optimization. We demonstrate the power of our new framework using confocal microscopy images of cells in a developing zebrafish

  12. Symmetry-adapted perturbation theory with Kohn-Sham orbitals using non-empirically tuned, long-range-corrected density functionals

    SciTech Connect

    Lao, Ka Un; Herbert, John M.

    2014-01-28

    The performance of second-order symmetry-adapted perturbation theory (SAPT) calculations using Kohn-Sham (KS) orbitals is evaluated against benchmark results for intermolecular interactions. Unlike previous studies of this “SAPT(KS)” methodology, the present study uses non-empirically tuned long-range corrected (LRC) functionals for the monomers. The proper v{sub xc} (r)→0 asymptotic limit is achieved by tuning the range separation parameter in order to satisfy the condition that the highest occupied KS energy level equals minus the molecule's ionization energy, for each monomer unit. Tests for He{sub 2}, Ne{sub 2}, and the S22 and S66 data sets reveal that this condition is important for accurate prediction of the non-dispersion components of the energy, although errors in SAPT(KS) dispersion energies remain unacceptably large. In conjunction with an empirical dispersion potential, however, the SAPT(KS) method affords good results for S22 and S66, and also accurately predicts the whole potential energy curve for the sandwich isomer of the benzene dimer. Tuned LRC functionals represent an attractive alternative to other asymptotic corrections that have been employed in density-functional-based SAPT calculations, and we recommend the use of tuned LRC functionals in both coupled-perturbed SAPT(DFT) calculations and dispersion-corrected SAPT(KS) calculations.

  13. HIV-1 Adaptation to Antigen Processing Results in Population-Level Immune Evasion and Affects Subtype Diversification

    PubMed Central

    Tenzer, Stefan; Crawford, Hayley; Pymm, Phillip; Gifford, Robert; Sreenu, Vattipally B.; Weimershaus, Mirjana; de Oliveira, Tulio; Burgevin, Anne; Gerstoft, Jan; Akkad, Nadja; Lunn, Daniel; Fugger, Lars; Bell, John; Schild, Hansjörg; van Endert, Peter; Iversen, Astrid K.N.

    2014-01-01

    Summary The recent HIV-1 vaccine failures highlight the need to better understand virus-host interactions. One key question is why CD8+ T cell responses to two HIV-Gag regions are uniquely associated with delayed disease progression only in patients expressing a few rare HLA class I variants when these regions encode epitopes presented by ∼30 more common HLA variants. By combining epitope processing and computational analyses of the two HIV subtypes responsible for ∼60% of worldwide infections, we identified a hitherto unrecognized adaptation to the antigen-processing machinery through substitutions at subtype-specific motifs. Multiple HLA variants presenting epitopes situated next to a given subtype-specific motif drive selection at this subtype-specific position, and epitope abundances correlate inversely with the HLA frequency distribution in affected populations. This adaptation reflects the sum of intrapatient adaptations, is predictable, facilitates viral subtype diversification, and increases global HIV diversity. Because low epitope abundance is associated with infrequent and weak T cell responses, this most likely results in both population-level immune evasion and inadequate responses in most people vaccinated with natural HIV-1 sequence constructs. Our results suggest that artificial sequence modifications at subtype-specific positions in vitro could refocus and reverse the poor immunogenicity of HIV proteins. PMID:24726370

  14. The Multi Level Multi Domain (MLMD) method: a semi-implicit adaptive algorithm for Particle In Cell plasma simulations

    NASA Astrophysics Data System (ADS)

    Innocenti, Maria Elena; Beck, Arnaud; Markidis, Stefano; Lapenta, Giovanni

    2013-10-01

    Particle in Cell (PIC) simulations of plasmas are not bound anymore by the stability constraints of explicit algorithms. Semi implicit and fully implicit methods allow to use larger grid spacings and time steps. Adaptive Mesh Refinement (AMR) techniques permit to locally change the simulation resolution. The code proposed in Innocenti et al., 2013 and Beck et al., 2013 is however the first to combine the advantages of both. The use of the Implicit Moment Method allows to taylor the resolution used in each level to the physical scales of interest and to use high Refinement Factors (RF) between the levels. The Multi Level Multi Domain (MLMD) structure, where all levels are simulated as complete domains, conjugates algorithmic and practical advantages. The different levels evolve according to the local dynamics and achieve optimal level interlocking. Also, the capabilities of the Object Oriented programming model are fully exploited. The MLMD algorithm is demonstrated with magnetic reconnection and collisionless shocks simulations with very high RFs between the levels. Notable computational gains are achieved with respect to simulations performed on the entire domain with the higher resolution. Beck A. et al. (2013). submitted. Innocenti M. E. et al. (2013). JCP, 238(0):115-140.

  15. A Comparison of Model-Data Fit for Parametric and Nonparametric Item Response Theory Models Using Ordinal-Level Ratings

    ERIC Educational Resources Information Center

    Dyehouse, Melissa A.

    2009-01-01

    This study compared the model-data fit of a parametric item response theory (PIRT) model to a nonparametric item response theory (NIRT) model to determine the best-fitting model for use with ordinal-level alternate assessment ratings. The PIRT Generalized Graded Unfolding Model (GGUM) was compared to the NIRT Mokken model. Chi-square statistics…

  16. Mycobacterium tuberculosis Lsr2 Is a Global Transcriptional Regulator Required for Adaptation to Changing Oxygen Levels and Virulence

    PubMed Central

    Bartek, I. L.; Woolhiser, L. K.; Baughn, A. D.; Basaraba, R. J.; Jacobs, W. R.; Lenaerts, A. J.

    2014-01-01

    ABSTRACT To survive a dynamic host environment, Mycobacterium tuberculosis must endure a series of challenges, from reactive oxygen and nitrogen stress to drastic shifts in oxygen availability. The mycobacterial Lsr2 protein has been implicated in reactive oxygen defense via direct protection of DNA. To examine the role of Lsr2 in pathogenesis and physiology of M. tuberculosis, we generated a strain deleted for lsr2. Analysis of the M. tuberculosis Δlsr2 strain demonstrated that Lsr2 is not required for DNA protection, as this strain was equally susceptible as the wild type to DNA-damaging agents. The lsr2 mutant did display severe growth defects under normoxic and hyperoxic conditions, but it was not required for growth under low-oxygen conditions. However, it was also required for adaptation to anaerobiosis. The defect in anaerobic adaptation led to a marked decrease in viability during anaerobiosis, as well as a lag in recovery from it. Gene expression profiling of the Δlsr2 mutant under aerobic and anaerobic conditions in conjunction with published DNA binding-site data indicates that Lsr2 is a global transcriptional regulator controlling adaptation to changing oxygen levels. The Δlsr2 strain was capable of establishing an early infection in the BALB/c mouse model; however, it was severely defective in persisting in the lungs and caused no discernible lung pathology. These findings demonstrate M. tuberculosis Lsr2 is a global transcriptional regulator required for control of genes involved in adaptation to extremes in oxygen availability and is required for persistent infection. PMID:24895305

  17. Electronic Level Structure and Excitation Modes in Semiconductor Superlattices and D-Parameter Theory.

    NASA Astrophysics Data System (ADS)

    Zhang, Jian

    1990-01-01

    The electronic level structure of a doped semiconductor superlattice such as GaAs-Al_chiGa _{1-chi}As has been calculated self-consistently in a tight-binding envelope function approximation, where inhomogeneous potentials related to depletion regions in real systems have been incorporated. Fermi-level pinning associated with depletion regions at the ends of the superlattice gives rise to surface -localized states lying in the miniband gaps and exhibiting localized eigenstates. Varying barrier transparency and doping density are shown to affect the location of these surface levels within the minigap. The application of a gate voltage across the superlattice structure produces drastic changes ill the level structure, including transitions from the extended to localized behavior in some eigenstates concurrent to shifts in their energies. We further present a theoretical study of the far-infrared response of these systems using the d-parameter formalism. The d( omega) functions, which parametrize the optical response of surfaces, provide position and coupling strengths for all possible optically active modes. d parameters have been used in the study of surfaces and the formalism is adapted here to the study of semiconductor superlattice systems. Intra- and inter-miniband plasma modes as well as single-particle-like transitions, are studied in 'bulk' and in finite-size superlattices. A series of surface modes, related to the charge depletion in the end layers of the superlattice, are distinguishable from the bulk modes. These additional modes are characterized by strong oscillations of the induced charge density near the surface layers, in contrast to the bulk modes which exhibit oscillations throughout the superlattice. The d-parameter formalism is further developed to study a quasi-zero-dimensional quantum dot system with electrons confined inside dots.

  18. The immunological aspects in adaptive reaction of mice in different levels of gravity

    NASA Astrophysics Data System (ADS)

    Berendeeva, Tatiana; Ponomarev, Sergey; Rykova, Marina; Boris, Morukov; Antropova, Evgeniya; Morukov, Ivan

    Experiments on animals exposed on board the spacecraft provide unique opportunity to study the immunological aspects of the development of adaptive reactions in microgravity. The aim of the study was a comprehensive research of immunocompetent cells and cytokine production in mice were on board biological satellite "Bion-M1". It was carried out a comprehensive study of bone marrow cells and spleen cells of mice line C57black/6, were in a real microgravity, and control groups. It was found that the conditions of 30-day spaceflight led to the increase of CD4+-T-lymphocytes in bone marrow and the increase of ability of bone marrow cells to produce Interleukin-1 which known as a key factor in increasing the osteoclastic bone resorption. At the same time, the relative content of lymphocytes in the spleen of mice that expressed on the cell membrane receptors CD19, CD3, CD4, CD8, CD25 and CD335, after the 30-day flight in near-earth orbit was not significantly change. It should be noted that the ability spleen cells to spontaneous and PHA-stimulated synthesis of IL-1 decreased. Analysis of the content of IL-8, IL-6, IL-17, TNFa, IL-4, IL-10, IFNg in supernatants from 48-hour unstimulated and PHA-stimulated cultures of spleen and bone marrow cells revealed no significant effect 30-day stay in conditions of microgravity on their products. The investigation was supported by Grant RFBR № 12-04-00803a.

  19. A Domain-Decomposed Multi-Level Method for Adaptively Refined Cartesian Grids with Embedded Boundaries

    NASA Technical Reports Server (NTRS)

    Aftosmis, M. J.; Berger, M. J.; Adomavicius, G.; Nixon, David (Technical Monitor)

    1998-01-01

    The work presents a new method for on-the-fly domain decomposition technique for mapping grids and solution algorithms to parallel machines, and is applicable to both shared-memory and message-passing architectures. It will be demonstrated on the Cray T3E, HP Exemplar, and SGI Origin 2000. Computing time has been secured on all these platforms. The decomposition technique is an outgrowth of techniques used in computational physics for simulations of N-body problems and the event horizons of black holes, and has not been previously used by the CFD community. Since the technique offers on-the-fly partitioning, it offers a substantial increase in flexibility for computing in heterogeneous environments, where the number of available processors may not be known at the time of job submission. In addition, since it is dynamic it permits the job to be repartitioned without global communication in cases where additional processors become available after the simulation has begun, or in cases where dynamic mesh adaptation changes the mesh size during the course of a simulation. The platform for this partitioning strategy is a completely new Cartesian Euler solver tarcreted at parallel machines which may be used in conjunction with Ames' "Cart3D" arbitrary geometry simulation package.

  20. Nociceptin/Orphanin FQ Suppresses Adaptive Immune Responses in Vivo and at Picomolar Levels in Vitro

    PubMed Central

    Anton, Benito; Calva, Juan C.; Acevedo, Rodolfo; Salazar, Alberto; Matus, Maura; Flores, Anabel; Martinez, Martin; Adler, Martin W.; Gaughan, John P.; Eisenstein, Toby K.

    2014-01-01

    Nociceptin/orphanin FQ (N/OFQ), added in vitro to murine spleen cells in the picomolar range, suppressed antibody formation to sheep red blood cells in a primary and a secondary plaque-forming cell (PFC) assay. The activity of the peptide was maximal at 10−12 M, with an asymmetric U-shaped dose response curve that extended activity to 10−14 M. Suppression was not blocked by pretreatment with naloxone. Specificity of the suppressive response was shown using affinity purified rabbit antibodies against two N/OFQ peptides, and with a pharmacological antagonist. Antisera against both peptides were active, in a dose related manner, in neutralizing N/OFQ -mediated immunosuppression, when the peptide was used at concentrations from 10−12.3 to 10−11.6 M. In addition, nociceptin given in vivo by osmotic pump for 48 hr suppressed the capacity of spleen cells placed ex vivo to make an anti-sheep red blood cell response. These studies show that nociceptin directly inhibits an adaptive immune response, i.e. antibody formation, both in vitro and in vivo. PMID:20119853

  1. Multi-level Dynamical Systems: Connecting the Ruelle Response Theory and the Mori-Zwanzig Approach

    NASA Astrophysics Data System (ADS)

    Wouters, J.; Lucarini, V.

    2012-12-01

    In this paper we consider the problem of disentangling multi-level systems by connecting the seemingly unrelated approaches of the Mori-Zwanzig projection operator technique and of the Ruelle response theory, for which we propose a new derivation. In a previous paper we have shown that by using the Ruelle response theory it is possible to construct a surrogate dynamics for the slow variables only such that the expectation value of any observable agrees, up to second order, to its expectation evaluated on the full dynamics, where both slow and fast variables are involved. We prove here, using a Dyson expansion, that such surrogate dynamics agree up to second order to the effective dynamics one can derive by expanding perturbatively the Mori-Zwanzing projection operator, which creates, instead, an accurate representation of the trajectories of the slow variables. In the case of e.g. geophysical fluid dynamics, this implies that the parametrizations of unresolved processes suited for prediction (numerical weather forecast) and those suited for the representation of long term statistical properties (climate) are closely related, if one takes into account, in addition to the widely adopted stochastic forcing, the usually neglected memory effects. This bears relevance for the current trend of aiming at seamless prediction.

  2. Reaction and Adaptation to the Birth of a Child: A Couple-Level Analysis

    ERIC Educational Resources Information Center

    Dyrdal, Gunvor Marie; Lucas, Richard E.

    2013-01-01

    The present study explored how life satisfaction changes before and after childbirth among first-time parents from a nationally representative, longitudinal study of Germans. Life satisfaction increased before pregnancy to a peak just after birth and then returned to the baseline level within 2 years postpartum. The 2 members of the same couple…

  3. Sea Level Rise Decision Support Tools for Adaptation Planning in Vulnerable Coastal Communities

    NASA Astrophysics Data System (ADS)

    Rozum, J. S.; Marcy, D.

    2015-12-01

    NOAA is involved in a myriad of climate related research and projects that help decision makers and the public understand climate science as well as climate change impacts. The NOAA Office for Coastal Management (OCM) provides data, tools, trainings and technical assistance to coastal resource managers. Beginning in 2011, NOAA OCM began developing a sea level rise and coastal flooding impacts viewer which provides nationally consistent data sets and analyses to help communities with coastal management goals such as: understanding and communicating coastal flood hazards, performing vulnerability assessments and increasing coastal resilience, and prioritizing actions for different inundation/flooding scenarios. The Viewer is available on NOAA's Digital Coast platform: (coast.noaa.gov/ditgitalcoast/tools/slr). In this presentation we will share the lessons learned from our work with coastal decision-makers on the role of coastal flood risk data and tools in helping to shape future land use decisions and policies. We will also focus on a recent effort in California to help users understand the similarities and differences of a growing array of sea level rise decision support tools. NOAA staff and other partners convened a workshop entitled, "Lifting the Fog: Bringing Clarity to Sea Level Rise and Shoreline Change Models and Tools," which was attended by tool develops, science translators and coastal managers with the goal to create a collaborative communication framework to help California coastal decision-makers navigate the range of available sea level rise planning tools, and to inform tool developers of future planning needs. A sea level rise tools comparison matrix will be demonstrated. This matrix was developed as part of this effort and has been expanded to many other states via a partnership with NOAA, Climate Central, and The Nature Conservancy.

  4. Analytical theory of strongly correlated Wigner crystals in the lowest Landau level

    NASA Astrophysics Data System (ADS)

    Rhim, Jun-Won; Jain, Jainendra K.; Park, Kwon

    2015-09-01

    In this work, we present an analytical theory of strongly correlated Wigner crystals (WCs) in the lowest Landau level (LLL) by constructing an approximate, but accurate effective two-body interaction for composite fermions (CFs) participating in the WCs. This requires integrating out the degrees of freedom of all surrounding CFs, which we accomplish analytically by approximating their wave functions by delta functions. This method produces energies of various strongly correlated WCs that are in excellent agreement with those obtained from the Monte Carlo simulation of the full CF crystal wave functions. We compute the compressibility of the strongly correlated WCs in the LLL and predict discontinuous changes at the phase boundaries separating different crystal phases.

  5. Defects in Chern-Simons theory, gauged WZW models on the brane, and level-rank duality

    NASA Astrophysics Data System (ADS)

    Armoni, Adi; Niarchos, Vasilis

    2015-07-01

    We consider Hanany-Witten setups of 3- and 5-branes in type IIB string theory that realize , (2, 0) and (1, 1) gauged WZW models in 1 + 1 dimensions. The gauged WZW models arise as theories residing on the boundary of D3 branes ending on D5 branes. From the point of view of low energy dynamics the D5 branes play the role of half-BPS co-dimension-1 defects (domain walls) in 3d or Chern-Simons theories. Extending the analysis of previous works on the subject of boundary conditions in (supersymmetric) Chern-Simons theory, we discuss in detail the field theory construction of a large class of Chern-Simons domain wall theories and its embedding in open string dynamics. Finally, we exhibit how standard brane moves that result to 3d Seiberg duality, translate in our setup to a generalized level-rank duality in gauged-WZW models.

  6. Population-Level Immune-Mediated Adaptation in HIV-1 Polymerase during the North American Epidemic

    PubMed Central

    Kinloch, Natalie N.; MacMillan, Daniel R.; Le, Anh Q.; Cotton, Laura A.; Bangsberg, David R.; Buchbinder, Susan; Carrington, Mary; Fuchs, Jonathan; Harrigan, P. Richard; Koblin, Beryl; Kushel, Margot; Markowitz, Martin; Mayer, Kenneth; Milloy, M. J.; Schechter, Martin T.; Wagner, Theresa; Walker, Bruce D.; Carlson, Jonathan M.; Poon, Art F. Y.

    2015-01-01

    ABSTRACT Human leukocyte antigen (HLA) class I-associated polymorphisms in HIV-1 that persist upon transmission to HLA-mismatched hosts may spread in the population as the epidemic progresses. Transmission of HIV-1 sequences containing such adaptations may undermine cellular immune responses to the incoming virus in future hosts. Building upon previous work, we investigated the extent of HLA-associated polymorphism accumulation in HIV-1 polymerase (Pol) through comparative analysis of linked HIV-1/HLA class I genotypes sampled during historic (1979 to 1989; n = 338) and modern (2001 to 2011; n = 278) eras from across North America (Vancouver, BC, Canada; Boston, MA; New York, NY; and San Francisco, CA). Phylogenies inferred from historic and modern HIV-1 Pol sequences were star-like in shape, with an inferred most recent common ancestor (epidemic founder virus) sequence nearly identical to the modern North American subtype B consensus sequence. Nevertheless, modern HIV-1 Pol sequences exhibited roughly 2-fold-higher patristic (tip-to-tip) genetic distances than historic sequences, with HLA pressures likely driving ongoing diversification. Moreover, the frequencies of published HLA-associated polymorphisms in individuals lacking the selecting HLA class I allele was on average ∼2.5-fold higher in the modern than in the historic era, supporting their spread in circulation, though some remained stable in frequency during this time. Notably, polymorphisms restricted by protective HLA alleles appear to be spreading to a greater relative extent than others, though these increases are generally of modest absolute magnitude. However, despite evidence of polymorphism spread, North American hosts generally remain at relatively low risk of acquiring an HIV-1 polymerase sequence substantially preadapted to their HLA profiles, even in the present era. IMPORTANCE HLA class I-restricted cytotoxic T-lymphocyte (CTL) escape mutations in HIV-1 that persist upon transmission may

  7. Multiresolution stroke sketch adaptive representation and neural network processing system for gray-level image recognition

    NASA Astrophysics Data System (ADS)

    Meystel, Alexander M.; Rybak, Ilya A.; Bhasin, Sanjay

    1992-11-01

    This paper describes a method for multiresolutional representation of gray-level images as hierarchial sets of strokes characterizing forms of objects with different degrees of generalization depending on the context of the image. This method transforms the original image into a hierarchical graph which allows for efficient coding in order to store, retrieve, and recognize the image. The method which is described is based upon finding the resolution levels for each image which minimizes the computations required. This becomes possible because of the use of a special image representation technique called Multiresolutional Attentional Representation for Recognition, based upon a feature which the authors call a stroke. This feature turns out to be efficient in the process of finding the appropriate system of resolutions and construction of the relational graph. Multiresolutional Attentional Representation for Recognition (MARR) is formed by a multi-layer neural network with recurrent inhibitory connections between neurons, the receptive fields of which are selectively tuned to detect the orientation of local contrasts in parts of the image with appropriate degree of generalization. This method simulates the 'coarse-to-fine' algorithm which an artist usually uses, making at attentional sketch of real images. The method, algorithms, and neural network architecture in this system can be used in many machine-vision systems with AI properties; in particular, robotic vision. We expect that systems with MARR can become a component of intelligent control systems for autonomous robots. Their architectures are mostly multiresolutional and match well with the multiple resolutions of the MARR structure.

  8. Theory of sub-Doppler cooling of three-level {Lambda} atoms in standing light waves

    SciTech Connect

    Kosachev, D.V.; Rozhdestvenskii, Yu.V.

    1994-12-01

    A general theory of cooling of three-level {Lambda} atoms in two standing light waves between which there is a relative spatial phase shift is presented for arbitrary ratios of the intensity and detuning. It is shown that in the case of equal detuning of the light waves, deep (sub-Doppler) cooling of three-level atoms occurs for any values of the spatial phase shift. For zero spatial phase shift, the atoms are strongly cooled due to coherent population trapping in the given atom-field interaction scheme. On the other hand, for the case of different frequency detunings, sub-Doppler cooling of {Lambda} atoms is possible only with a nonzero relative phase shift; it is shown that this is associated with the so-called {open_quotes}Sisyphus{close_quotes} cooling mechanism. The authors underscore that in their scheme neither a polarization gradient of the exciting waves nor a magnetic field is required to achieve this type of cooling pattern; two standing waves acting on different transitions of a {Lambda} atom are sufficient. 13 refs., 10 figs.

  9. Adaptation to the impact of sea level rise in the Northeastern Nile Delta, Egypt

    NASA Astrophysics Data System (ADS)

    Mabrouk, Badr; Farhat Abd-Elhamid, Hany; Badr, Marmar; Ludwig, Ralf

    2013-04-01

    Northeastern Delta is one of the most promising developmental areas in Egypt. This area is characterized by a prominent watershed having abundant water resources (especially groundwater). Currently, this area undergoes a rapid environmental degradation, such as land subsidence, water and soil salinaization. It accommodates about 60% of the total arable lands of the Delta, and inhabited by about 45 % of its total population. In addition, the northern part of this area comprises about 25% of the total Mediterranean wetlands. In this area a number of desalination plants were installed to desalinate brackish water and inject the brine to the aquifer using deep wells. This work aims to evaluate the environmental impact of injecting brine water on groundwater quality. Also, the impact of climate change and sea level rise are considered. The work is a combination of field work and simulation processes of groundwater flow and seawater intrusion using numerical models. The field work was used to collect and analyze data, information pertaining to the groundwater resources, interpretation of aerial photos and satellite images and preparation of ground water potential maps has. This was followed by detailed test boring wells as chemical analysis of seawater intrusion detection and pollution flow mapping were done. Numerical models (MODFLOW and MT3D) were used to evaluate both current and future situation of the groundwater flow and seawater intrusion in the Nile Delta aquifer in the studied area. The aquifer in the studied area is divided into five barrier beds according to its hydrological characteristics. The increase in extraction rates of brackish water and increasing the salinity of groundwater were experienced in details. Different scenarios to mitigate the severe salinity effect of injected brine water of high salinity rejected from desalination process. The brine water is assumed to be injected into deep wells to different depths and observation of changes in salinity

  10. Viral adaptation to an antiviral protein enhances the fitness level to above that of the uninhibited wild type.

    PubMed

    Cherwa, James E; Sanchez-Soria, Pablo; Wichman, Holly A; Fane, Bentley A

    2009-11-01

    Viruses often evolve resistance to antiviral agents. While resistant strains are able to replicate in the presence of the agent, they generally exhibit lower fitness than the wild-type strain in the absence of the inhibitor. In some cases, resistant strains become dependent on the antiviral agent. However, the agent rarely, if ever, elevates dependent strain fitness above the uninhibited wild-type level. This would require an adaptive mechanism to convert the antiviral agent into a beneficial growth factor. Using an inhibitory scaffolding protein that specifically blocks phiX174 capsid assembly, we demonstrate that such mechanisms are possible. To obtain the quintuple-mutant resistant strain, the wild-type virus was propagated for approximately 150 viral life cycles in the presence of increasing concentrations of the inhibitory protein. The expression of the inhibitory protein elevated the strain's fitness significantly above the uninhibited wild-type level. Thus, selecting for resistance coselected for dependency, which was characterized and found to operate on the level of capsid nucleation. To the best of our knowledge, this is the first report of a virus evolving a mechanism to productively utilize an antiviral agent to stimulate its fitness above the uninhibited wild-type level. The results of this study may be predictive of the types of resistant phenotypes that could be selected by antiviral agents that specifically target capsid assembly. PMID:19726521

  11. Mineral accretion technology for coral reef restoration, shore protection, and adaptation to rising sea level

    SciTech Connect

    Goreau, T.J.; Hilbertz, W.

    1997-12-31

    Electrolysis of seawater is used to precipitate limestone on top of underwater steel structures to create growing artificial reefs to enhance coral growth, restore coral reef habitat, provide shelter for fish, shellfish, and other marine organisms, generate white sand for beach replenishment, and protect shore lines from wave erosion. Films and slides will be shown of existing structures in Jamaica, Panama, and the Maldives, and projects being developed in these and other locations will be evaluated. The method is unique because it creates the only artificial reef structures that generate the natural limestone substrate from which corals and coral reefs are composed, speeding the settlement and growth of calcareous organisms, and attracting the full range of other reef organisms. The structures are self-repairing and grow stronger with age. Power sources utilized include batteries, battery chargers, photovoltaic panels, and windmills. The cost of seawalls and breakwaters produced by this method is less than one tenth that of conventional technology. Because the technology is readily scaled up to build breakwaters and artificial islands able to keep pace with rising sea level it is capable of playing an important role in protecting low lying coastal areas from the effects of global climate change.

  12. Anatomically-adapted graph wavelets for improved group-level fMRI activation mapping.

    PubMed

    Behjat, Hamid; Leonardi, Nora; Sörnmo, Leif; Van De Ville, Dimitri

    2015-12-01

    A graph based framework for fMRI brain activation mapping is presented. The approach exploits the spectral graph wavelet transform (SGWT) for the purpose of defining an advanced multi-resolutional spatial transformation for fMRI data. The framework extends wavelet based SPM (WSPM), which is an alternative to the conventional approach of statistical parametric mapping (SPM), and is developed specifically for group-level analysis. We present a novel procedure for constructing brain graphs, with subgraphs that separately encode the structural connectivity of the cerebral and cerebellar gray matter (GM), and address the inter-subject GM variability by the use of template GM representations. Graph wavelets tailored to the convoluted boundaries of GM are then constructed as a means to implement a GM-based spatial transformation on fMRI data. The proposed approach is evaluated using real as well as semi-synthetic multi-subject data. Compared to SPM and WSPM using classical wavelets, the proposed approach shows superior type-I error control. The results on real data suggest a higher detection sensitivity as well as the capability to capture subtle, connected patterns of brain activity. PMID:26057594

  13. Skeletal Adaptations to Different Levels of Eccentric Resistance Following Eight Weeks of Training

    NASA Technical Reports Server (NTRS)

    English, Kirk L.; Loehr, James A.; Lee, Stuart M. C.; Maddocks, Mary J.; Laughlin, Mitzi S.; Hagan, R. Donald

    2007-01-01

    Coupled concentric-eccentric resistive exercise maintains bone mineral density (BMD) during bed rest and aging. PURPOSE: We hypothesized that 8 wks of lower body resistive exercise training with higher ratios of eccentric to concentric loading would enhance hip and lumbar BMD. METHODS: Forty untrained male volunteers (34.9+/-7.0 yrs, 80.9+/-9.8 kg, 178.2+/-7.1 cm; mean+/-SD) were matched for leg press (LP) 1-Repetition Maximum (1-RM) strength and randomly assigned to one of 5 training groups. Concentric load (% 1-RM) was constant across groups, but each group trained with different levels of eccentric load (0, 33, 66, 100, or 138% of concentric) for all training sessions. Subjects performed a periodized supine LP and heel raise (HR) training program 3 d wk-1 for 8 wks using a modified Agaton Fitness System (Agaton Fitness AB, Boden, Sweden). Hip and lumbar BMD (g/sq cm) was measured in triplicate pre- and post-training using DXA (Hologic Discovery ). Pre- and post-training means were compared using the appropriate ANOVA and Tukey's post hoc tests. Within group pre- to post-training BMD was compared using paired t-tests with a Bonferroni adjustment. RESULTS: There was a main effect of training on L1, L2, L3, L4, total lumbar, and greater trochanter BMD, but there were no differences between groups. CONCLUSION: Eights wks of lower body resistive exercise increased greater trochanter and lumbar BMD. Inability to detect group differences may have been influenced by a potentially osteogenic vibration associated with device operation in the 0, 33, and 66% groups.

  14. Modeled Sea Level Rise Impacts on Coastal Ecosystems at Six Major Estuaries on Florida's Gulf Coast: Implications for Adaptation Planning.

    PubMed

    Geselbracht, Laura L; Freeman, Kathleen; Birch, Anne P; Brenner, Jorge; Gordon, Doria R

    2015-01-01

    The Sea Level Affecting Marshes Model (SLAMM) was applied at six major estuaries along Florida's Gulf Coast (Pensacola Bay, St. Andrews/Choctawhatchee Bays, Apalachicola Bay, Southern Big Bend, Tampa Bay and Charlotte Harbor) to provide quantitative and spatial information on how coastal ecosystems may change with sea level rise (SLR) and to identify how this information can be used to inform adaption planning. High resolution LiDAR-derived elevation data was utilized under three SLR scenarios: 0.7 m, 1 m and 2 m through the year 2100 and uncertainty analyses were conducted on selected input parameters at three sites. Results indicate that the extent, spatial orientation and relative composition of coastal ecosystems at the study areas may substantially change with SLR. Under the 1 m SLR scenario, total predicted impacts for all study areas indicate that coastal forest (-69,308 ha; -18%), undeveloped dry land (-28,444 ha; -2%) and tidal flat (-25,556 ha; -47%) will likely face the greatest loss in cover by the year 2100. The largest potential gains in cover were predicted for saltmarsh (+32,922 ha; +88%), transitional saltmarsh (+23,645 ha; na) and mangrove forest (+12,583 ha; +40%). The Charlotte Harbor and Tampa Bay study areas were predicted to experience the greatest net loss in coastal wetlands The uncertainty analyses revealed low to moderate changes in results when some numerical SLAMM input parameters were varied highlighting the value of collecting long-term sedimentation, accretion and erosion data to improve SLAMM precision. The changes predicted by SLAMM will affect exposure of adjacent human communities to coastal hazards and ecosystem functions potentially resulting in impacts to property values, infrastructure investment and insurance rates. The results and process presented here can be used as a guide for communities vulnerable to SLR to identify and prioritize adaptation strategies that slow and/or accommodate the changes underway. PMID:26207914

  15. A review of the multi-level adaptations for maximizing aerobic dive duration in marine mammals: from biochemistry to behavior.

    PubMed

    Davis, Randall W

    2014-01-01

    Marine mammals exhibit multi-level adaptations, from cellular biochemistry to behavior, that maximize aerobic dive duration. A dive response during aerobic dives enables the efficient use of blood and muscle oxygen stores, but it is exercise modulated to maximize the aerobic dive limit at different levels of exertion. Blood volume and concentrations of blood hemoglobin and muscle myoglobin are elevated and serve as a significant oxygen store that increases aerobic dive duration. However, myoglobin is not homogeneously distributed in the locomotory muscles and is highest in areas that produce greater force and consume more oxygen during aerobic swimming. Muscle fibers are primarily fast and slow twitch oxidative with elevated mitochondrial volume densities and enhanced oxidative enzyme activities that are highest in areas that produce more force generation. Most of the muscle mitochondria are interfibriller and homogeneously distributed. This reduces the diffusion distance between mitochondria and helps maintain aerobic metabolism under hypoxic conditions. Mitochondrial volume densities and oxidative enzyme activities are also elevated in certain organs such as liver, kidneys, and stomach. Hepatic and renal function along with digestion and assimilation continue during aerobic dives to maintain physiological homeostasis. Most ATP production comes from aerobic fat metabolism in carnivorous marine mammals. Glucose is derived mostly from gluconeogenesis and is conserved for tissues such as red blood cells and the central nervous system. Marine mammals minimize the energetic cost of swimming and diving through body streamlining, efficient, lift-based propulsive appendages, and cost-efficient modes of locomotion that reduce drag and take advantage of changes in buoyancy with depth. Most dives are within the animal's aerobic dive limit, which maximizes time underwater and minimizes recovery time at the surface. The result of these adaptations is increased breath

  16. Analysing agricultural drought vulnerability at sub-district level through exposure, sensitivity and adaptive capacity based composite index

    NASA Astrophysics Data System (ADS)

    Murthy, C. S.; Laxman, B.; Sesha Sai, M. V. R.; Diwakar, P. G.

    2014-11-01

    Information on agricultural drought vulnerability status of different regions is extremely useful for implementation of long term drought management measures. A quantitative approach for measuring agricultural drought vulnerability at sub-district level was developed and implemented in the current study, which was carried-out in Andhra Pradesh state, India with the data of main cropping season i.e., kharif. The contributing indicators represent exposure, sensitivity and adaptive capacity components of vulnerability and were drawn from weather, soil, crop, irrigation and land holdings related data. After performing data normalisation and variance based weights generation, component wise composite indices were generated. Agricultural Drought Vulnerability Index (ADVI) was generated using the three component indices and beta distribution was fitted to it. Mandals (sub-district level administrative units) of the state were categorised into 5 classes - Less vulnerable, Moderately vulnerable, Vulnerable, Highly vulnerable and Very highly vulnerable. Districts dominant with vulnerable Mandals showed considerably larger variability of detrended yields of principal crops compared to the other districts, thus validating the index based vulnerability status. Current status of agricultural drought vulnerability in the state, based on ADVI, indicated that vulnerable to very highly vulnerable group of Mandals represent 54 % of total Mandals and about 55 % of the agricultural area and 65 % of the rainfed crop area. The variability in the agricultural drought vulnerability at disaggregated level was effectively captured by ADVI. The vulnerability status map is useful for diagnostic analysis and for formulating vulnerability reduction plans.

  17. Development 3D model of adaptation of the Azerbaijan coastal zone at the various levels of Caspian Sea

    NASA Astrophysics Data System (ADS)

    Mammadov, Ramiz

    2013-04-01

    coastal areas at hydraulic engineering projects the sea level should be considered as multistage process, what we have considered by development of adaptation of a coastal zone The exact three-dimensional map of a coastal zone has been created. For different scenario sea levels, or example, -30.0; -29.0; -28.0; -27.0; -26.0; -25.0 and -24.0 exact coastal lines have been certain. Further maps of a vegetative cover, ground, social and economic and ecological conditions have been developed for different level and respective alterations are certain. More vulnerable coastal zone, flooded area and socio-economic damage were estimated.

  18. Adaptive multi-level conditional random fields for detection and segmentation of small enhanced pathology in medical images.

    PubMed

    Karimaghaloo, Zahra; Arnold, Douglas L; Arbel, Tal

    2016-01-01

    Detection and segmentation of large structures in an image or within a region of interest have received great attention in the medical image processing domains. However, the problem of small pathology detection and segmentation still remains an unresolved challenge due to the small size of these pathologies, their low contrast and variable position, shape and texture. In many contexts, early detection of these pathologies is critical in diagnosis and assessing the outcome of treatment. In this paper, we propose a probabilistic Adaptive Multi-level Conditional Random Fields (AMCRF) with the incorporation of higher order cliques for detecting and segmenting such pathologies. In the first level of our graphical model, a voxel-based CRF is used to identify candidate lesions. In the second level, in order to further remove falsely detected regions, a new CRF is developed that incorporates higher order textural features, which are invariant to rotation and local intensity distortions. At this level, higher order textures are considered together with the voxel-wise cliques to refine boundaries and is therefore adaptive. The proposed algorithm is tested in the context of detecting enhancing Multiple Sclerosis (MS) lesions in brain MRI, where the problem is further complicated as many of the enhancing voxels are associated with normal structures (i.e. blood vessels) or noise in the MRI. The algorithm is trained and tested on large multi-center clinical trials from Relapsing-Remitting MS patients. The effect of several different parameter learning and inference techniques is further investigated. When tested on 120 cases, the proposed method reaches a lesion detection rate of 90%, with very few false positive lesion counts on average, ranging from 0.17 for very small (3-5 voxels) to 0 for very large (50+ voxels) regions. The proposed model is further tested on a very large clinical trial containing 2770 scans where a high sensitivity of 91% with an average false positive

  19. Incorporating immersive virtual environments in health promotion campaigns: a construal level theory approach.

    PubMed

    Ahn, Sun Joo Grace

    2015-01-01

    In immersive virtual environments (IVEs), users may observe negative consequences of a risky health behavior in a personally involving way via digital simulations. In the context of an ongoing health promotion campaign, IVEs coupled with pamphlets are proposed as a novel messaging strategy to heighten personal relevance and involvement with the issue of soft-drink consumption and obesity, as well as perceptions that the risk is proximal and imminent. The framework of construal level theory guided the design of a 2 (tailoring: other vs. self) × 2 (medium: pamphlet only vs. pamphlet with IVEs) between-subjects experiment to test the efficacy in reducing the consumption of soft drinks over 1 week. Immediately following exposure, tailoring the message to the self (vs. other) seemed to be effective in reducing intentions to consume soft drinks. The effect of tailoring dissipated after 1 week, and measures of actual soft-drink consumption 1 week following experimental treatments demonstrated that coupling IVEs with the pamphlet was more effective. Behavioral intention was a significant predictor of actual behavior, but underlying mechanisms driving intentions and actual behavior were distinct. Results prescribed a messaging strategy that incorporates both tailoring and coupling IVEs with traditional media to increase behavioral changes over time. PMID:24991725

  20. Unconscious high-level information processing: implication for neurobiological theories of consciousness.

    PubMed

    van Gaal, Simon; Lamme, Victor A F

    2012-06-01

    Theories about the neural correlates and functional relevance of consciousness have traditionally assigned a crucial role to the prefrontal cortex in generating consciousness as well as in orchestrating high-level conscious control over behavior. However, recent neuroscientific findings show that prefrontal cortex can be activated unconsciously. The depth, direction, and scope of these activations depend on several top-down factors such as the task being probed (task-set, strategy) and on (temporal/spatial) attention. Regardless, such activations-when mediated by feedforward activation only-do not lead to a conscious sensation. Although unconscious, these prefrontal activations are functional, in the sense that they are associated with behavioral effects of cognitive control, such as response inhibition, task switching, conflict monitoring, and error detection. These findings challenge the pivotal role of the prefrontal cortex in consciousness. Instead, it appears that specific brain areas (or cognitive modules) may support specific cognitive functions but that consciousness is independent of this. Conscious sensations arise only when the brain areas involved engage in recurrent interactions enabling the long-lasting exchange of information between brain regions. Moreover, recent evidence suggests that also the state of consciousness, for example, in vegetative state patients or during sleep and anesthesia, is closely related to the scope and extent of residual recurrent interactions among brain regions. PMID:21628675

  1. A review of national-level adaptation planning with regards to the risks posed by climate change on infectious diseases in 14 OECD nations.

    PubMed

    Panic, Mirna; Ford, James D

    2013-12-01

    Climate change is likely to have significant implications for human health, particularly through alterations of the incidence, prevalence, and distribution of infectious diseases. In the context of these risks, governments in high income nations have begun developing strategies to reduce potential climate change impacts and increase health system resilience (i.e., adaptation). In this paper, we review and evaluate national-level adaptation planning in relation to infectious disease risks in 14 OECD countries with respect to "best practices" for adaptation identified in peer-reviewed literature. We find a number of limitations to current planning, including negligible consideration of the needs of vulnerable population groups, limited emphasis on local risks, and inadequate attention to implementation logistics, such as available funding and timelines for evaluation. The nature of planning documents varies widely between nations, four of which currently lack adaptation plans. In those countries where planning documents were available, adaptations were mainstreamed into existing public health programs, and prioritized a sectoral, rather than multidisciplinary, approach. The findings are consistent with other scholarship examining adaptation planning indicating an ad hoc and fragmented process, and support the need for enhanced attention to adaptation to infectious disease risks in public health policy at a national level. PMID:24351735

  2. A Review of National-Level Adaptation Planning with Regards to the Risks Posed by Climate Change on Infectious Diseases in 14 OECD Nations

    PubMed Central

    Panic, Mirna; Ford, James D.

    2013-01-01

    Climate change is likely to have significant implications for human health, particularly through alterations of the incidence, prevalence, and distribution of infectious diseases. In the context of these risks, governments in high income nations have begun developing strategies to reduce potential climate change impacts and increase health system resilience (i.e., adaptation). In this paper, we review and evaluate national-level adaptation planning in relation to infectious disease risks in 14 OECD countries with respect to “best practices” for adaptation identified in peer-reviewed literature. We find a number of limitations to current planning, including negligible consideration of the needs of vulnerable population groups, limited emphasis on local risks, and inadequate attention to implementation logistics, such as available funding and timelines for evaluation. The nature of planning documents varies widely between nations, four of which currently lack adaptation plans. In those countries where planning documents were available, adaptations were mainstreamed into existing public health programs, and prioritized a sectoral, rather than multidisciplinary, approach. The findings are consistent with other scholarship examining adaptation planning indicating an ad hoc and fragmented process, and support the need for enhanced attention to adaptation to infectious disease risks in public health policy at a national level. PMID:24351735

  3. Design of a Two-level Adaptive Multi-Agent System for Malaria Vectors driven by an ontology

    PubMed Central

    Koum, Guillaume; Yekel, Augustin; Ndifon, Bengyella; Etang, Josiane; Simard, Frédéric

    2007-01-01

    Background The understanding of heterogeneities in disease transmission dynamics as far as malaria vectors are concerned is a big challenge. Many studies while tackling this problem don't find exact models to explain the malaria vectors propagation. Methods To solve the problem we define an Adaptive Multi-Agent System (AMAS) which has the property to be elastic and is a two-level system as well. This AMAS is a dynamic system where the two levels are linked by an Ontology which allows it to function as a reduced system and as an extended system. In a primary level, the AMAS comprises organization agents and in a secondary level, it is constituted of analysis agents. Its entry point, a User Interface Agent, can reproduce itself because it is given a minimum of background knowledge and it learns appropriate "behavior" from the user in the presence of ambiguous queries and from other agents of the AMAS in other situations. Results Some of the outputs of our system present a series of tables, diagrams showing some factors like Entomological parameters of malaria transmission, Percentages of malaria transmission per malaria vectors, Entomological inoculation rate. Many others parameters can be produced by the system depending on the inputted data. Conclusion Our approach is an intelligent one which differs from statistical approaches that are sometimes used in the field. This intelligent approach aligns itself with the distributed artificial intelligence. In terms of fight against malaria disease our system offers opportunities of reducing efforts of human resources who are not obliged to cover the entire territory while conducting surveys. Secondly the AMAS can determine the presence or the absence of malaria vectors even when specific data have not been collected in the geographical area. In the difference of a statistical technique, in our case the projection of the results in the field can sometimes appeared to be more general. PMID:17605778

  4. SU-E-E-07: An Adaptable Approach for Education On Medical Physics at Undergraduate and Postgraduate Levels

    SciTech Connect

    Miller-Clemente, R; Mendez-Perez, L

    2015-06-15

    Purpose: To contribute to the professional profile of future medical physicists, technologists and physicians, and implement an adaptable educational strategy at both undergraduate and postgraduate levels. Methods: The Medical Physics Block of Electives (MPBE) designed was adapted to the Program of B.S. in Physics. The conferences and practical activities were developed with participatory methods, with interdisciplinary collaboration from research institutions and hospitals engaged on projects of Research, Development and Innovation (RDI). The scientific education was implemented by means of critical analysis of scientific papers and seminars where students debated on solutions for real research problems faced by medical physicists. This approach included courses for graduates not associated to educational programs of Medical Physics (MP). Results: The implementation of the MPBE began in September 2014, with the electives of Radiation MP and Introduction to Nuclear Magnetic Resonance. The students of second year received an Introduction to MP. This initiative was validated by the departmental Methodological Workshop, which promoted the full implementation of the MPBE. Both postgraduated and undergraduate trainees participated in practices with our DICOM viewer system, a local prototype for photoplethysmography and a home-made interface for ROC analysis, built with MATLAB. All these tools were designed and constructed in previous RDI projects. The collaborative supervision of University’s researchers with clinical medical physicists will allow to overcome the limitations of residency in hospitals, to reduce the workload for clinical supervisors and develop appropriate educational activities. Conclusion: We demonstrated the feasibility of adaptable educational strategies, considering available resources. This provides an innovative way for prospective medical physicists, technologists and radiation oncologists. This strategy can be implemented in several regions

  5. Factorial Equivalence of Social Cognitive Theory: Educational Levels × Time Differences

    ERIC Educational Resources Information Center

    Phan, Huy Phuong; Ngu, Bing

    2014-01-01

    The study of social cognitive theory has involved a number of inquiries, notably one of which concerns the formation and development of self-efficacy beliefs. Social cognitive theory indicates that we form our self-efficacy beliefs from four major sources of information: enactive performance accomplishments, vicarious experiences, verbal…

  6. Development and Evaluation of the Brief Sexual Openness Scale—A Construal Level Theory Based Approach

    PubMed Central

    Chen, Xinguang; Wang, Yan; Li, Fang; Gong, Jie; Yan, Yaqiong

    2015-01-01

    Obtaining reliable and valid data on sensitive questions represents a longstanding challenge for public health, particularly HIV research. To overcome the challenge, we assessed a construal level theory (CLT)-based novel method. The method was previously established and pilot-tested using the Brief Sexual Openness Scale (BSOS). This scale consists of five items assessing attitudes toward premarital sex, multiple sexual partners, homosexuality, extramarital sex, and commercial sex, all rated on a standard 5-point Likert scale. In addition to self-assessment, the participants were asked to assess rural residents, urban residents, and foreigners. The self-assessment plus the assessment of the three other groups were all used as subconstructs of one latent construct: sexual openness. The method was validated with data from 1,132 rural-to-urban migrants (mean age = 32.5, SD = 7.9; 49.6% female) recruited in China. Consistent with CLT, the Cronbach alpha of the BSOS as a conventional tool increased with social distance, from .81 for self-assessment to .97 for assessing foreigners. In addition to a satisfactory fit of the data to a one-factor model (CFI = .94, TLI = .93, RMSEA = .08), a common factor was separated from the four perspective factors (i.e., migrants’ self-perspective and their perspectives of rural residents, urban residents and foreigners) through a trifactor modeling analysis (CFI = .95, TLI = .94, RMSEA = .08). Relative to its conventional form, CTL-based BSOS was more reliable (alpha: .96 vs .81) and valid in predicting sexual desire, frequency of dating, age of first sex, multiple sexual partners and STD history. This novel technique can be used to assess sexual openness, and possibly other sensitive questions among Chinese domestic migrants. PMID:26308336

  7. High propionic acid fermentations and mineral accumulation in the cecum of rats adapted to different levels of inulin.

    PubMed

    Levrat, M A; Rémésy, C; Demigné, C

    1991-11-01

    The digestive and metabolic effects of inulin (from chicory) were studied in rats adapted to semipurified diets containing 0, 5, 10 or 20% inulin (wt/wt). Moderate levels of inulin (5-10%) did not significantly affect food intake or body weight gain. Dietary inulin resulted in considerably greater cecal fermentation and a significantly greater intraluminal concentration of propionate (peaking at 58.4 mmol/L). A lower concentration of acetate (42.6 mmol/L) was observed in rats fed 20% inulin. Lactic fermentations were observed in rats fed the 10 or 20% inulin diets. The cecal pool of volatile fatty acids tended to reach a plateau in rats fed diets containing more than 10% inulin (up to 600-700 mumol), but volatile fatty acid absorption was a slightly hyperbolic function of the dietary inulin level. Butyrate absorption was proportionally lower than that of propionate. Inulin-containing diets induced an enlargement of the cecal pool of calcium, phosphate and (to a lesser extent) magnesium. There was also an enhanced absorption of these divalent cations. The cecal pool of bile acids was greater in rats fed inulin, and this oligosaccharide displayed a slight hypocholesterolemic effect, even in rats fed the 5% inulin diet. However, plasma triglycerides were depressed only in rats fed the 20% inulin diet. In conclusion, inulin seems very effective in promoting propionic fermentation and in enhancing the calcium content of the large intestine. However, high levels of inulin (greater than 10%) may affect growth in rats and lead to acidic (pH 5.65) cecal fermentation. PMID:1941180

  8. Adapting to Sea Level Rise and Storms: Missed Opportunities and Continuing Development (case studies from USA and Bulgaria)

    NASA Astrophysics Data System (ADS)

    Young, Robert; Stancheva, Margarita; Stanchev, Hristo; Palazov, Atanas; Peek, Katie; Coburn, Andrew; Griffith, Adam

    2014-05-01

    Over the last several years, there have been significant discussions within the global scientific and coastal zone management communities about the need to adapt to the realities of long-term sea level rise and to make coastal development more "resilient" to hazards and climate change. With all of the talk, publications, and recognition of the problem, you would think that we had made significant progress, but this is not the case. Once again, the USA has experienced the impact of a significant coastal storm, Hurricane Sandy. There were initially some serious post-Sandy discussions regarding the need to ensure that we simply don't "just put everything back were it was." Almost a year later, there have been few substantive moves to relocate property away from coastal hazards or to change the footprint of vulnerable coastal communities. This is particularly true of coastal resort communities in New York and New Jersey. Some communities have initiated large-scale efforts to elevate (in situ) infrastructure and private property. Raising buildings is only a workable solution if you also commit to holding all the beaches in place . . . forever. This is what the federal government has done for New Jersey and New York. The U. S. Army Corps of Engineers will be spending upward of US5 billion on shore protection projects following Hurricane Sandy. The vast majority of these funds will be spent pumping sand onto beaches from Delaware to Connecticut. The amount of sand they will move is staggering, approaching 25 to 35 million cubic meters. This is an adaptation model that cannot be exported to the rest of the USA. Nor can it be maintained for an extended period of time. Along the Black Sea Coast of Bulgaria the risk of storms is not as great as that of the US East Coast, but long-term sea level rise is still a threat. In Bulgaria, most coastal development problems occur simply because people continue to build in areas that are too close to the coast or in very high hazard

  9. Adaptation of Pseudomonas putida S12 to ethanol and toluene at the level of fatty acid composition of membranes

    SciTech Connect

    Heipieper, H.J.; De Bont, J.A.M.

    1994-12-01

    Many organic solvents are toxic to organisms because the partition preferentially in membranes. However, microorganisms can adapt to different organic substances. In this paper, the authors investigate the effects of both ethanol and toluene on these adaptation mechanisms in Pseudomonas putida S12 and demonstrated that isomerization allows a swifter adaptation than the growth-dependent system, which relies on changes in the degree of saturation. 34 refs., 4 figs.

  10. Adaptation as organism design

    PubMed Central

    Gardner, Andy

    2009-01-01

    The problem of adaptation is to explain the apparent design of organisms. Darwin solved this problem with the theory of natural selection. However, population geneticists, whose responsibility it is to formalize evolutionary theory, have long neglected the link between natural selection and organismal design. Here, I review the major historical developments in theory of organismal adaptation, clarifying what adaptation is and what it is not, and I point out future avenues for research. PMID:19793739

  11. Adapting coastal structures to a moving relative sea level: Roman Time geoarchaeological evidence from Posillipo promontory (Naples, Italy).

    NASA Astrophysics Data System (ADS)

    Aucelli, Pietro; Cinque, Aldo; Giordano, Francesco; Mattei, Gaia; Pappone, Gerardo; Rizzo, Angela

    2016-04-01

    The Posillipo promontory belongs to the southern periphery the active volcanic complex called Campi Flegrei. Especially the central caldera of CF is well known for offering a rich geoarchaeological record of the vertical ground movements it has been suffering since Roman times; which includes the ruins of Portus Julius (built in 37 BC) presently found between 10 and 5 m bsl and the Middle Ages Lithophaga perforations at about 7m asl on the marble columns of the Serapeo building (Morhange, 2006 and references therein). In order to better constraint the vertical movements suffered by the Posillipo promontory during the last two millennia, we selected three geoarcaeolgical coastal sites (Nisida Roman port, Marechiaro Roman port and Villa Robery) and we studied them by means of both geomorphological observations and geophysical surveys (Side Scan Sonar and Single Beam echo-sounder). Within the submerged Roman port of Nisida, built in the 1st AD, we found two pilae of the ancient pier. The submersion measuring of the well-preserved one provided a palaeo-sea level at 3.1±0.30 m bsl. In the submerged Roman port of Marechiaro, we recognized a still preserved breakwater connected to the tuffaceous sea cliff, and submerged foundations of a 1st century small sea-side villa. Nearby there is also a two-storeyed Roman building (Palazzo degli Spiriti), built in the 1st cent. BC and later restructured to adapt to a phase of subsidence (Gunther 1908). From our submersion measurements, two different paleo-sea levels can be deduced: one for the 1st cent. BC at -4.4 + -0.50 m and another for the 1st cent. AD at -3 + - 0.30 m. Finally, in front of the modern Villa Rosebery the sea bottom shows a sub-horizontal element at -3m to -3.5m bsl, emerged during the 1st BC century. In fact, at least three houses were erected there during said century (Gunther, 1908). As the area was very little elevated, an alignment of pilae was also constructed to protect those houses from the breakers. By

  12. Expanding Acculturation Theory: Are Acculturation Models and the Adaptiveness of Acculturation Strategies Generalizable in a Colonial Context?

    ERIC Educational Resources Information Center

    Cheung-Blunden, Violet L.; Juang, Linda P.

    2008-01-01

    Most acculturation research has been conducted in immigrant settings. The present study examined the generalizability of acculturation models and the adaptiveness of acculturation strategies in another bicultural environment--a colonial setting. The sample included 138 girls (M = 13.8 years) and their parents from Hong Kong, a former British…

  13. "Computerized Adaptive Testing: Theory and Practice." Wim J. van der Linden and Cees A. W. Glas, Eds. [book review].

    ERIC Educational Resources Information Center

    Reise, Steven P.

    2001-01-01

    This book contains a series of research articles about computerized adaptive testing (CAT) written for advanced psychometricians. The book is divided into sections on: (1) item selection and examinee scoring in CAT; (2) examples of CAT applications; (3) item banks; (4) determining model fit; and (5) using testlets in CAT. (SLD)

  14. Functional-Notional Concepts: Adapting the Foreign Language Textbook. Language in Education: Theory and Practice, No. 44.

    ERIC Educational Resources Information Center

    Guntermann, Gail; Phillips, June K.

    Textbooks currently available for foreign language instruction are generally oriented toward instruction in grammar for its own sake. Until materials are developed that are specifically geared to a systematic development of communicative competence, textbooks must be adapted. This handbook is directed toward that need. It emphasizes the following…

  15. A Comparison of an Expert Systems Approach to Computerized Adaptive Testing and an Item Response Theory Model.

    ERIC Educational Resources Information Center

    Frick, Theodore W.

    Expert systems can be used to aid decisionmaking. A computerized adaptive test is one kind of expert system, although not commonly recognized as such. A new approach, termed EXSPRT, was devised that combines expert systems reasoning and sequential probability ratio test stopping rules. Two versions of EXSPRT were developed, one with random…

  16. Toward a Theory of Adaptive Transfer: Expanding Disciplinary Discussions of "Transfer" in Second-Language Writing and Composition Studies

    ERIC Educational Resources Information Center

    DePalma, Michael-John; Ringer, Jeffrey M.

    2011-01-01

    In this paper, we argue that discussions of transfer in L2 writing and composition studies have focused primarily on the reuse of past learning and thus have not adequately accounted for the adaptation of learned writing knowledge in unfamiliar situations. In an effort to expand disciplinary discussions of transfer in L2 writing and composition…

  17. A Comparative Analysis of Multiple Intelligence Theory with Relationship to Gender and Grade Level in Selected Schools in Ghana

    ERIC Educational Resources Information Center

    Oteng, Ellen N.

    2012-01-01

    This dissertation examined the relationships between Howard Gardner's Multiple Intelligence Theory and students' gender, age, grade level, and enrollment into a public or private school. The research determined students' dominant intelligences and investigated whether students' intelligences may be influenced by demographic…

  18. A Study to Relate the Theories of John Dewey to College Level Speech-Communication Education. Final Report.

    ERIC Educational Resources Information Center

    Haase, Mary

    This report presents a synthesis of John Dewey's concepts of man-to-man speech-communication located in numerous speeches and in other relevant Dewey writings. The communication theories are formulated in a verbal model and related to college level speech-communication education. Dewey's views of communication as cooperative, communal phenomena…

  19. Transforming Passive Receptivity of Knowledge into Deep Learning Experiences at the Undergraduate Level: An Example from Music Theory

    ERIC Educational Resources Information Center

    Ferenc, Anna

    2015-01-01

    This article discusses transformation of passive knowledge receptivity into experiences of deep learning in a lecture-based music theory course at the second-year undergraduate level through implementation of collaborative projects that evoke natural critical learning environments. It presents an example of such a project, addresses key features…

  20. Survey of Global Simulation at the Intersection of Theory and Practice in the Intermediate-Level German Classroom

    ERIC Educational Resources Information Center

    Levine, Glenn S.; Eppelsheimer, Natalie; Kuzay, Franz; Moti, Simona; Wilby, Jason

    2004-01-01

    The article presents a format for intermediate, university-level German instruction called "global simulation" (GS) as the curricular manifestation of several recent trends in the literature on instructed second-language acquisition, in particular interactionist and task-based approaches, sociocultural theory, and the acquisition of intercultural…

  1. Teaching for Transfer: Insights from Theory and Practices in Primary-Level French-Second-Language Classrooms

    ERIC Educational Resources Information Center

    Thomas, Reed; Mady, Callie

    2014-01-01

    This paper illustrates teaching for transfer across languages by synthesizing key insights from theory and previously published research alongside our case study data from primary-level teachers in core French-second-language (CF) classrooms in Ontario, Canada. Drawing on research that redefines language transfer as a resource, this study drew on…

  2. Prospective Teachers' Comprehension Levels of Special Relativity Theory and the Effect of Writing for Learning on Achievement

    ERIC Educational Resources Information Center

    Yildiz, Ali

    2012-01-01

    In the present study, the comprehension levels of special relativity theory in prospective teachers who take the Introduction to Modern Physics lesson in the faculty of education science teaching department and the effect of writing for learning on their achievement is researched. In the research, a control group pre-test post-test…

  3. Intermolecular forces and molecular dynamics simulation of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) using symmetry adapted perturbation theory.

    PubMed

    Taylor, DeCarlos E

    2013-04-25

    The dimer potential energy surface (PES) of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) has been explored using symmetry adapted perturbation theory based on a Kohn-Sham density functional theory description of the monomers [SAPT(DFT)]. An intermolecular potential energy function was parametrized using a grid of 880 ab initio SAPT(DFT) dimer interaction energies, and the function was used to identify stationary points on the SAPT(DFT) dimer PES. It is shown that there exists a variety of minima with a range of bonding configurations and ab initio analyses of the interaction energy components, along with radial cross sections of the PES near each minimum, are presented. Results of isothermal-isostress molecular dynamics simulations are reported, and the simulated structure, thermal expansion, sublimation enthalpy, and bulk modulus of the TATB crystal, based on the SAPT(DFT) interaction potential, are in good agreement with experiment. PMID:23565605

  4. Applications of network analysis for adaptive management of artificial drainage systems in landscapes vulnerable to sea level rise

    NASA Astrophysics Data System (ADS)

    Poulter, Benjamin; Goodall, Jonathan L.; Halpin, Patrick N.

    2008-08-01

    SummaryThe vulnerability of coastal landscapes to sea level rise is compounded by the existence of extensive artificial drainage networks initially built to lower water tables for agriculture, forestry, and human settlements. These drainage networks are found in landscapes with little topographic relief where channel flow is characterized by bi-directional movement across multiple time-scales and related to precipitation, wind, and tidal patterns. The current configuration of many artificial drainage networks exacerbates impacts associated with sea level rise such as salt-intrusion and increased flooding. This suggests that in the short-term, drainage networks might be managed to mitigate sea level rise related impacts. The challenge, however, is that hydrologic processes in regions where channel flow direction is weakly related to slope and topography require extensive parameterization for numerical models which is limited where network size is on the order of a hundred or more kilometers in total length. Here we present an application of graph theoretic algorithms to efficiently investigate network properties relevant to the management of a large artificial drainage system in coastal North Carolina, USA. We created a digital network model representing the observation network topology and four types of drainage features (canal, collector and field ditches, and streams). We applied betweenness-centrality concepts (using Dijkstra's shortest path algorithm) to determine major hydrologic flowpaths based off of hydraulic resistance. Following this, we identified sub-networks that could be managed independently using a community structure and modularity approach. Lastly, a betweenness-centrality algorithm was applied to identify major shoreline entry points to the network that disproportionately control water movement in and out of the network. We demonstrate that graph theory can be applied to solving management and monitoring problems associated with sea level rise

  5. Ozone levels in the Empty Quarter of Saudi Arabia--application of adaptive neuro-fuzzy model.

    PubMed

    Rahman, Syed Masiur; Khondaker, A N; Khan, Rouf Ahmad

    2013-05-01

    In arid regions, primary pollutants may contribute to the increase of ozone levels and cause negative effects on biotic health. This study investigates the use of adaptive neuro-fuzzy inference system (ANFIS) for ozone prediction. The initial fuzzy inference system is developed by using fuzzy C-means (FCM) and subtractive clustering (SC) algorithms, which determines the important rules, increases generalization capability of the fuzzy inference system, reduces computational needs, and ensures speedy model development. The study area is located in the Empty Quarter of Saudi Arabia, which is considered as a source of huge potential for oil and gas field development. The developed clustering algorithm-based ANFIS model used meteorological data and derived meteorological data, along with NO and NO₂ concentrations and their transformations, as inputs. The root mean square error and Willmott's index of agreement of the FCM- and SC-based ANFIS models are 3.5 ppbv and 0.99, and 8.9 ppbv and 0.95, respectively. Based on the analysis of the performance measures and regression error characteristic curves, it is concluded that the FCM-based ANFIS model outperforms the SC-based ANFIS model. PMID:23111771

  6. Adapting SAFT-γ perturbation theory to site-based molecular dynamics simulation. III. Molecules with partial charges at bulk phases, confined geometries and interfaces

    SciTech Connect

    Ghobadi, Ahmadreza F.; Elliott, J. Richard

    2014-09-07

    In Paper I [A. F. Ghobadi and J. R. Elliott, J. Chem. Phys. 139(23), 234104 (2013)], we showed that how a third-order Weeks–Chandler–Anderson (WCA) Thermodynamic Perturbation Theory and molecular simulation can be integrated to characterize the repulsive and dispersive contributions to the Helmholtz free energy for realistic molecular conformations. To this end, we focused on n-alkanes to develop a theory for fused and soft chains. In Paper II [A. F. Ghobadi and J. R. Elliott, J. Chem. Phys. 141(2), 024708 (2014)], we adapted the classical Density Functional Theory and studied the microstructure of the realistic molecular fluids in confined geometries and vapor-liquid interfaces. We demonstrated that a detailed consistency between molecular simulation and theory can be achieved for both bulk and inhomogeneous phases. In this paper, we extend the methodology to molecules with partial charges such as carbon dioxide, water, 1-alkanols, nitriles, and ethers. We show that the electrostatic interactions can be captured via an effective association potential in the framework of Statistical Associating Fluid Theory (SAFT). Implementation of the resulting association contribution in assessing the properties of these molecules at confined geometries and interfaces presents satisfactory agreement with molecular simulation and experimental data. For example, the predicted surface tension deviates less than 4% comparing to full potential simulations. Also, the theory, referred to as SAFT-γ WCA, is able to reproduce the specific orientation of hydrophilic head and hydrophobic tail of 1-alkanols at the vapor-liquid interface of water.

  7. Adapting SAFT-γ perturbation theory to site-based molecular dynamics simulation. III. Molecules with partial charges at bulk phases, confined geometries and interfaces

    NASA Astrophysics Data System (ADS)

    Ghobadi, Ahmadreza F.; Elliott, J. Richard

    2014-09-01

    In Paper I [A. F. Ghobadi and J. R. Elliott, J. Chem. Phys. 139(23), 234104 (2013)], we showed that how a third-order Weeks-Chandler-Anderson (WCA) Thermodynamic Perturbation Theory and molecular simulation can be integrated to characterize the repulsive and dispersive contributions to the Helmholtz free energy for realistic molecular conformations. To this end, we focused on n-alkanes to develop a theory for fused and soft chains. In Paper II [A. F. Ghobadi and J. R. Elliott, J. Chem. Phys. 141(2), 024708 (2014)], we adapted the classical Density Functional Theory and studied the microstructure of the realistic molecular fluids in confined geometries and vapor-liquid interfaces. We demonstrated that a detailed consistency between molecular simulation and theory can be achieved for both bulk and inhomogeneous phases. In this paper, we extend the methodology to molecules with partial charges such as carbon dioxide, water, 1-alkanols, nitriles, and ethers. We show that the electrostatic interactions can be captured via an effective association potential in the framework of Statistical Associating Fluid Theory (SAFT). Implementation of the resulting association contribution in assessing the properties of these molecules at confined geometries and interfaces presents satisfactory agreement with molecular simulation and experimental data. For example, the predicted surface tension deviates less than 4% comparing to full potential simulations. Also, the theory, referred to as SAFT-γ WCA, is able to reproduce the specific orientation of hydrophilic head and hydrophobic tail of 1-alkanols at the vapor-liquid interface of water.

  8. Communicating Climate Change Science to Stakeholders for Assessments of Impact and Adaptation: Experiences at the Municipal Level in Canada

    NASA Astrophysics Data System (ADS)

    Hill, P. R.; Mate, D.; Tansey, J. D.

    2004-12-01

    The assessment of climate change impacts and the identification of adaptation strategies require understandable communication of climate change science and its uncertainties to a diverse group of stakeholders. This paper will report on the experience being gained from a set of municipal case studies conducted in Canada, where climate change impacts such as water resource depletion, permafrost melting and coastal sea level rise are being addressed. Two aspects will be discussed: the local process of stakeholder interaction and the effort to bring the local experiences to a national level through development of municipal best practice guides. Ideally, stakeholders are engaged at the local level through a structured process. This is to avoid the common problem that pre-existing tensions between stakeholders tend to dominate unstructured discussions and distract attention from the target issue. One-on-one interviews with the stakeholders and research into the socio-economic history of the communities provide background on the issues that may arise before group workshops are attempted. When workshops involving stakeholders are held, they are professionally facilitated and the science delivery is carefully rationed into digestible portions that enable informed discussion of specific climate change scenarios. Municipalities can be engaged at political, practitioner and public levels not only as major stakeholders, but also as key partners in the communication process. We have used presentations to council, direct involvement of city planning departments and public events such as Science and Technology Week to nurture two-way communication. We have also put considerable thought into the effort to communicate these experiences to the over one thousand communities across the country that will not benefit from a case study. Our initial approach was to develop best practice guides on climate change topics based on the successes and lessons learned in the case studies. While

  9. Public health and climate change adaptation at the federal level: one agency's response to Executive Order 13514.

    PubMed

    Hess, Jeremy J; Schramm, Paul J; Luber, George

    2014-03-01

    Climate change will likely have adverse human health effects that require federal agency involvement in adaptation activities. In 2009, President Obama issued Executive Order 13514, Federal Leadership in Environmental, Energy, and Economic Performance. The order required federal agencies to develop and implement climate change adaptation plans. The Centers for Disease Control and Prevention (CDC), as part of a larger Department of Health and Human Services response to climate change, is developing such plans. We provide background on Executive Orders, outline tenets of climate change adaptation, discuss public health adaptation planning at both the Department of Health and Human Services and the CDC, and outline possible future CDC efforts. We also consider how these activities may be better integrated with other adaptation activities that manage emerging health threats posed by climate change. PMID:24432931

  10. Public Health and Climate Change Adaptation at the Federal Level: One Agency’s Response to Executive Order 13514

    PubMed Central

    Schramm, Paul J.; Luber, George

    2014-01-01

    Climate change will likely have adverse human health effects that require federal agency involvement in adaptation activities. In 2009, President Obama issued Executive Order 13514, Federal Leadership in Environmental, Energy, and Economic Performance. The order required federal agencies to develop and implement climate change adaptation plans. The Centers for Disease Control and Prevention (CDC), as part of a larger Department of Health and Human Services response to climate change, is developing such plans. We provide background on Executive Orders, outline tenets of climate change adaptation, discuss public health adaptation planning at both the Department of Health and Human Services and the CDC, and outline possible future CDC efforts. We also consider how these activities may be better integrated with other adaptation activities that manage emerging health threats posed by climate change. PMID:24432931

  11. Item Response Theory at Subject- and Group-Level. Research Report 90-1.

    ERIC Educational Resources Information Center

    Tobi, Hilde

    This paper reviews the literature about item response models for the subject level and aggregated level (group level). Group-level item response models (IRMs) are used in the United States in large-scale assessment programs such as the National Assessment of Educational Progress and the California Assessment Program. In the Netherlands, these…

  12. Parallel three-dimensional magnetotelluric inversion using adaptive finite-element method. Part I: theory and synthetic study

    NASA Astrophysics Data System (ADS)

    Grayver, Alexander V.

    2015-07-01

    This paper presents a distributed magnetotelluric inversion scheme based on adaptive finite-element method (FEM). The key novel aspect of the introduced algorithm is the use of automatic mesh refinement techniques for both forward and inverse modelling. These techniques alleviate tedious and subjective procedure of choosing a suitable model parametrization. To avoid overparametrization, meshes for forward and inverse problems were decoupled. For calculation of accurate electromagnetic (EM) responses, automatic mesh refinement algorithm based on a goal-oriented error estimator has been adopted. For further efficiency gain, EM fields for each frequency were calculated using independent meshes in order to account for substantially different spatial behaviour of the fields over a wide range of frequencies. An automatic approach for efficient initial mesh design in inverse problems based on linearized model resolution matrix was developed. To make this algorithm suitable for large-scale problems, it was proposed to use a low-rank approximation of the linearized model resolution matrix. In order to fill a gap between initial and true model complexities and resolve emerging 3-D structures better, an algorithm for adaptive inverse mesh refinement was derived. Within this algorithm, spatial variations of the imaged parameter are calculated and mesh is refined in the neighborhoods of points with the largest variations. A series of numerical tests were performed to demonstrate the utility of the presented algorithms. Adaptive mesh refinement based on the model resolution estimates provides an efficient tool to derive initial meshes which account for arbitrary survey layouts, data types, frequency content and measurement uncertainties. Furthermore, the algorithm is capable to deliver meshes suitable to resolve features on multiple scales while keeping number of unknowns low. However, such meshes exhibit dependency on an initial model guess. Additionally, it is demonstrated

  13. Synergy and Antagonism of Active Constituents of ADAPT-232 on Transcriptional Level of Metabolic Regulation of Isolated Neuroglial Cells

    PubMed Central

    Panossian, Alexander; Hamm, Rebecca; Kadioglu, Onat; Wikman, Georg; Efferth, Thomas

    2013-01-01

    Gene expression profiling was performed on the human neuroglial cell line T98G after treatment with adaptogen ADAPT-232 and its constituents – extracts of Eleutherococcus senticosus root, Schisandra chinensis berry, and Rhodiola rosea root as well as several constituents individually, namely, eleutheroside E, schizandrin B, salidroside, triandrin, and tyrosol. A common feature for all tested adaptogens was their effect on G-protein-coupled receptor signaling pathways, i.e., cAMP, phospholipase C (PLC), and phosphatidylinositol signal transduction pathways. Adaptogens may reduce the cAMP level in brain cells by down-regulation of adenylate cyclase gene ADC2Y and up-regulation of phosphodiesterase gene PDE4D that is essential for energy homeostasis as well as for switching from catabolic to anabolic states and vice versa. Down-regulation of cAMP by adaptogens may decrease cAMP-dependent protein kinase A activity in various cells resulting in inhibition stress-induced catabolic transformations and saving of ATP for many ATP-dependant metabolic transformations. All tested adaptogens up-regulated the PLCB1 gene, which encodes phosphoinositide-specific PLC and phosphatidylinositol 3-kinases (PI3Ks), key players for the regulation of NF-κB-mediated defense responses. Other common targets of adaptogens included genes encoding ERα estrogen receptor (2.9–22.6 fold down-regulation), cholesterol ester transfer protein (5.1–10.6 fold down-regulation), heat shock protein Hsp70 (3.0–45.0 fold up-regulation), serpin peptidase inhibitor (neuroserpin), and 5-HT3 receptor of serotonin (2.2–6.6 fold down-regulation). These findings can be reconciled with the observed beneficial effects of adaptogens in behavioral, mental, and aging-associated disorders. Combining two or more active substances in one mixture significantly changes deregulated genes profiles: synergetic interactions result in activation of genes that none of the individual substances affected, while

  14. Adapting SAFT-γ perturbation theory to site-based molecular dynamics simulation. II. Confined fluids and vapor-liquid interfaces

    NASA Astrophysics Data System (ADS)

    Ghobadi, Ahmadreza F.; Elliott, J. Richard

    2014-07-01

    In this work, a new classical density functional theory is developed for group-contribution equations of state (EOS). Details of implementation are demonstrated for the recently-developed SAFT-γ WCA EOS and selective applications are studied for confined fluids and vapor-liquid interfaces. The acronym WCA (Weeks-Chandler-Andersen) refers to the characterization of the reference part of the third-order thermodynamic perturbation theory applied in formulating the EOS. SAFT-γ refers to the particular form of "statistical associating fluid theory" that is applied to the fused-sphere, heteronuclear, united-atom molecular models of interest. For the monomer term, the modified fundamental measure theory is extended to WCA-spheres. A new chain functional is also introduced for fused and soft heteronuclear chains. The attractive interactions are taken into account by considering the structure of the fluid, thus elevating the theory beyond the mean field approximation. The fluctuations of energy are also included via a non-local third-order perturbation theory. The theory includes resolution of the density profiles of individual groups such as CH2 and CH3 and satisfies stoichiometric constraints for the density profiles. New molecular simulations are conducted to demonstrate the accuracy of each Helmholtz free energy contribution in reproducing the microstructure of inhomogeneous systems at the united-atom level of coarse graining. At each stage, comparisons are made to assess where the present theory stands relative to the current state of the art for studying inhomogeneous fluids. Overall, it is shown that the characteristic features of real molecular fluids are captured both qualitatively and quantitatively. For example, the average pore density deviates ˜2% from simulation data for attractive pentadecane in a 2-nm slit pore. Another example is the surface tension of ethane/heptane mixture, which deviates ˜1% from simulation data while the theory reproduces the excess

  15. Adaptive Management for Decision Making at the Program and Project Levels of the Missouri River Recovery Program

    SciTech Connect

    Thom, Ronald M.; Anderson, Michael G.; Tyre, Drew; Fleming, Craig A.

    2009-02-28

    The paper, “Adaptive Management: Background for Stakeholders in the Missouri River Recovery Program,” introduced the concept of adaptive management (AM), its principles and how they relate to one-another, how AM is applied, and challenges for its implementation. This companion paper describes how the AM principles were applied to specific management actions within the Missouri River Recovery Program to facilitate understanding, decision-making, and stakeholder engagement. For context, we begin with a brief synopsis of the Missouri River Recovery Program (MRRP) and the strategy for implementing adaptive management (AM) within the program; we finish with an example of AM in action within Phase I of the MRPP.

  16. Adapting SAFT-γ perturbation theory to site-based molecular dynamics simulation. I. Homogeneous fluids

    NASA Astrophysics Data System (ADS)

    Ghobadi, Ahmadreza F.; Elliott, J. Richard

    2013-12-01

    In this work, we aim to develop a version of the Statistical Associating Fluid Theory (SAFT)-γ equation of state (EOS) that is compatible with united-atom force fields, rather than experimental data. We rely on the accuracy of the force fields to provide the relation to experimental data. Although, our objective is a transferable theory of interfacial properties for soft and fused heteronuclear chains, we first clarify the details of the SAFT-γ approach in terms of site-based simulations for homogeneous fluids. We show that a direct comparison of Helmholtz free energy to molecular simulation, in the framework of a third order Weeks-Chandler-Andersen perturbation theory, leads to an EOS that takes force field parameters as input and reproduces simulation results for Vapor-Liquid Equilibria (VLE) calculations. For example, saturated liquid density and vapor pressure of n-alkanes ranging from methane to dodecane deviate from those of the Transferable Potential for Phase Equilibria (TraPPE) force field by about 0.8% and 4%, respectively. Similar agreement between simulation and theory is obtained for critical properties and second virial coefficient. The EOS also reproduces simulation data of mixtures with about 5% deviation in bubble point pressure. Extension to inhomogeneous systems and united-atom site types beyond those used in description of n-alkanes will be addressed in succeeding papers.

  17. The Theory of Adaptive Dispersion and Acoustic-Phonetic Properties of Cross-Language Lexical-Tone Systems

    ERIC Educational Resources Information Center

    Alexander, Jennifer Alexandra

    2010-01-01

    Lexical-tone languages use fundamental frequency (F0/pitch) to convey word meaning. About 41.8% of the world's languages use lexical tone (Maddieson, 2008), yet those systems are under-studied. I aim to increase our understanding of speech-sound inventory organization by extending to tone-systems a model of vowel-system organization, the Theory of…

  18. Obstacles to adaptation decisions in the developing world: A case study of coastal protection measures and sea-level rise in Kiribati

    NASA Astrophysics Data System (ADS)

    Donner, S. D.; Webber, S.

    2014-12-01

    International aid is increasingly focused on adaptation to climate change. At recent meetings of the parties to the United Nations Framework Convention on Climate Change, the developed world agreed to rapidly increase international assistance to help the developing world respond to the impacts of climate change. Here, we examine the decision-making challenges facing internationally supported climate change adaptation projects given the large uncertainty in future climate predictions, using the example of efforts to implement coastal protection measures (e.g. sea walls, mangrove planting) in Kiribati. The central equatorial Pacific country is home to the Kiribati Adaptation Project, the first national-level climate change adaptation project supported by the World Bank. Drawing on interview and document research conducted over an 8-year period, we trace the forces influencing decisions about coastal protection measures, starting from the variability and uncertainty in climate change projections, through the trade-offs between different measures, to the social, political, and economic context in which decisions are finally made. We then discuss how sub-optimal adaptation measures may be implemented despite years of planning, consultation, and technical studies. This qualitative analysis of the real-world process of climate change adaptation reveals that embracing a culturally appropriate and short-term (~20 years) planning horizon, while not ignoring the longer-term future, may reduce the influence of scientific uncertainty on decisions and provide opportunities to learn from mistakes, reassess the science, and adjust suboptimal investments.

  19. [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. PMID:25051769

  20. Past and future corollaries of theories on causes of metabolic syndrome and obesity related co-morbidities part 2: a composite unifying theory review of human-specific co-adaptations to brain energy consumption.

    PubMed

    McGill, Anne-Thea

    2014-01-01

    Metabolic syndrome (MetS) predicts type II diabetes mellitus (TIIDM), cardiovascular disease (CVD) and cancer, and their rates have escalated over the last few decades. Obesity related co-morbidities also overlap the concept of the metabolic syndrome (MetS). However, understanding of the syndrome's underlying causes may have been misapprehended. The current paper follows on from a theory review by McGill, A-T in Archives of Public Health, 72: 30. This accompanying paper utilises research on human evolution and new biochemistry to theorise on why MetS and obesity arise and how they affect the population. The basis of this composite unifying theory is that the proportionately large, energy-demanding human brain may have driven co-adaptive mechanisms to provide, or conserve, energy for the brain. A 'dual system' is proposed. 1) The enlarged, complex cortico-limbic-striatal system increases dietary energy by developing strong neural self-reward/motivation pathways for the acquisition of energy dense food, and (2) the nuclear factor-erythroid 2-related factor 2 (NRF2) cellular protection system amplifies antioxidant, antitoxicant and repair activity by employing plant chemicals. In humans who consume a nutritious diet, the NRF2 system has become highly energy efficient. Other relevant human-specific co-adaptations are explored. In order to 'test' this composite unifying theory it is important to show that the hypothesis and sub-theories pertain throughout the whole of human evolution and history up till the current era. Corollaries of the composite unifying theory of MetS are examined with respect to past under-nutrition and malnutrition since agriculture began 10,000 years ago. The effects of man-made pollutants on degenerative change are examined. Projections are then made from current to future patterns on the state of 'insufficient micronutrient and/or unbalanced high energy malnutrition with central obesity and metabolic dysregulation' or 'malnubesity'. Forecasts

  1. Endogenous ROS levels in C. elegans under exogenous stress support revision of oxidative stress theory of life-history tradeoffs

    PubMed Central

    2014-01-01

    Background The oxidative stress theory of life-history tradeoffs states that oxidative stress caused by damaging free radicals directly underpins tradeoffs between reproduction and longevity by altering the allocation of energetic resources between these tasks. We test this theory by characterizing the effects of exogenous oxidative insult and its interaction with thermal stress and diet quality on a suite of life-history traits and correlations in Caenorhabditis elegans nematodes. We also quantify demographic aging rates and endogenous reactive oxygen species (ROS) levels in live animals. Results Our findings indicate a tradeoff between investment in reproduction and antioxidant defense (somatic maintenance) consistent with theoretical predictions, but correlations between standard life-history traits yield little evidence that oxidative stress generates strict tradeoffs. Increasing oxidative insult, however, shows a strong tendency to uncouple positive phenotypic correlations and, in particular, to reduce the correlation between reproduction and lifespan. We also found that mild oxidative insult results in lower levels of endogenous ROS accompanied by hormetic changes in lifespan, demographic aging, and reproduction that disappear in combined-stress treatments--consistent with the oxidative stress theory of aging. Conclusions Our findings demonstrate that oxidative stress is a direct contributor to life-history trait variation and that traditional tradeoffs are not necessary to invoke oxidative stress as a mediator of relationships between life-history traits, supporting previous calls for revisions to theory. PMID:25056725

  2. Formulation and implementation of a unitary group adapted state universal multi-reference coupled cluster (UGA-SUMRCC) theory: Excited and ionized state energies

    NASA Astrophysics Data System (ADS)

    Sen, Sangita; Shee, Avijit; Mukherjee, Debashis

    2012-08-01

    The traditional state universal multi-reference coupled cluster (SUMRCC) theory uses the Jeziorski-Monkhorst (JM) based Ansatz of the wave operator: Ω = ∑μΩμ|ϕμ⟩⟨ϕμ|, where Ωμ = exp (Tμ) is the cluster representation of the component of Ω inducing virtual excitations from the model function ϕμ. In the first formulations, ϕμs were chosen to be single determinants and Tμs were defined in terms of spinorbitals. This leads to spin-contamination for the non-singlet cases. In this paper, we propose and implement an explicitly spin-free realization of the SUMRCC theory. This method uses spin-free unitary generators in defining the cluster operators, {Tμ}, which even at singles-doubles truncation, generates non-commuting cluster operators. We propose the use of normal-ordered exponential parameterization for Ω:∑μ{exp (Tμ)}|ϕμ⟩⟨ϕμ|, where {} denotes the normal ordering with respect to a common closed shell vacuum which makes the "direct term" of the SUMRCC equations terminate at the quartic power. We choose our model functions {ϕμ} as unitary group adapted (UGA) Gel'fand states which is why we call our theory UGA-SUMRCC. In the spirit of the original SUMRCC, we choose exactly the right number of linearly independent cluster operators in {Tμ} such that no redundancies in the virtual functions lbrace χ _μ ^lrbrace are involved. Using example applications for electron detached/attached and h-p excited states relative to a closed shell ground state we discuss how to choose the most compact and non-redundant cluster operators. Although there exists a more elaborate spin-adapted JM-like ansatz of Datta and Mukherjee (known as combinatoric open-shell CC (COS-CC), its working equations are more complex. Results are compared with those from COS-CC, equation of motion coupled cluster methods, restricted open-shell Hartree-Fock coupled cluster, and full configuration interaction. We observe that our results are more accurate with respect to

  3. Past and future corollaries of theories on causes of metabolic syndrome and obesity related co-morbidities part 2: a composite unifying theory review of human-specific co-adaptations to brain energy consumption

    PubMed Central

    2014-01-01

    Forward A composite unifying theory on causes of obesity related-MetS has been formulated and published in an accompanying article (1). In the current article, the historical and recent past, present and future corollaries of this theory are discussed. By presenting this composite theory and corollaries, it is hoped that human evolution and physiology will be viewed and studied from a new vantage point. The politics of management of ecological farming and nutrition will change, a profound reconfiguration of scientific theory generation and advancement in a ‘high-tech’ world can be made, and pathways for solutions recognised. Metabolic syndrome (MetS) predicts type II diabetes mellitus (TIIDM), cardiovascular disease (CVD) and cancer, and their rates have escalated over the last few decades. Obesity related co-morbidities also overlap the concept of the metabolic syndrome (MetS). However, understanding of the syndrome’s underlying causes may have been misapprehended. The current paper follows on from a theory review by McGill, A-T in Archives of Public Health, 72: 30. This accompanying paper utilises research on human evolution and new biochemistry to theorise on why MetS and obesity arise and how they affect the population. The basis of this composite unifying theory is that the proportionately large, energy-demanding human brain may have driven co-adaptive mechanisms to provide, or conserve, energy for the brain. A ‘dual system’ is proposed. 1) The enlarged, complex cortico-limbic-striatal system increases dietary energy by developing strong neural self-reward/motivation pathways for the acquisition of energy dense food, and (2) the nuclear factor-erythroid 2-related factor 2 (NRF2) cellular protection system amplifies antioxidant, antitoxicant and repair activity by employing plant chemicals. In humans who consume a nutritious diet, the NRF2 system has become highly energy efficient. Other relevant human-specific co-adaptations are explored. In order to

  4. Adapting SAFT-γ perturbation theory to site-based molecular dynamics simulation. II. Confined fluids and vapor-liquid interfaces

    SciTech Connect

    Ghobadi, Ahmadreza F.; Elliott, J. Richard

    2014-07-14

    In this work, a new classical density functional theory is developed for group-contribution equations of state (EOS). Details of implementation are demonstrated for the recently-developed SAFT-γ WCA EOS and selective applications are studied for confined fluids and vapor-liquid interfaces. The acronym WCA (Weeks-Chandler-Andersen) refers to the characterization of the reference part of the third-order thermodynamic perturbation theory applied in formulating the EOS. SAFT-γ refers to the particular form of “statistical associating fluid theory” that is applied to the fused-sphere, heteronuclear, united-atom molecular models of interest. For the monomer term, the modified fundamental measure theory is extended to WCA-spheres. A new chain functional is also introduced for fused and soft heteronuclear chains. The attractive interactions are taken into account by considering the structure of the fluid, thus elevating the theory beyond the mean field approximation. The fluctuations of energy are also included via a non-local third-order perturbation theory. The theory includes resolution of the density profiles of individual groups such as CH{sub 2} and CH{sub 3} and satisfies stoichiometric constraints for the density profiles. New molecular simulations are conducted to demonstrate the accuracy of each Helmholtz free energy contribution in reproducing the microstructure of inhomogeneous systems at the united-atom level of coarse graining. At each stage, comparisons are made to assess where the present theory stands relative to the current state of the art for studying inhomogeneous fluids. Overall, it is shown that the characteristic features of real molecular fluids are captured both qualitatively and quantitatively. For example, the average pore density deviates ∼2% from simulation data for attractive pentadecane in a 2-nm slit pore. Another example is the surface tension of ethane/heptane mixture, which deviates ∼1% from simulation data while the theory

  5. Cloud base levels for Jupiter and Venus and the heteromolecular nucleation theory

    NASA Technical Reports Server (NTRS)

    Stauffer, D.; Kiang, C. S.

    1974-01-01

    For purified binary gas mixtures like NH3-H2O or HCl-H2O, partial pressures appreciably greater than the two saturation partial pressures are needed to condense the gas mixture into small solution droplets (homogeneous heteromolecular nucleation). Thus without foreign nuclei, clouds are not as easily formed as in the theories of Lewis; the latter should be valid only if large condensation nuclei are available. We calculate here from classical homogeneous heteromolecular nucleation theory the threshold partial pressures necessary to achieve droplet nucleation for the gas mixtures NH3-H2O (Jupiter), HCl-H2O (Venus), H2SO4-H2O (Venus), and C2H5OH-H2O (laboratory).

  6. Youth Empowerment Solutions for Peaceful Communities: combining theory and practice in a community-level violence prevention curriculum.

    PubMed

    Zimmerman, Marc A; Stewart, Sarah E; Morrel-Samuels, Susan; Franzen, Susan; Reischl, Thomas M

    2011-05-01

    This article describes the development and evaluation of an after-school curriculum designed to prepare adolescents to prevent violence through community change. This curriculum, part of the Youth Empowerment Solutions for Peaceful Communities (YES) program, is guided by empowerment and ecological theories within a positive youth development context. YES is designed to enhance the capacity of adolescents and adults to work together to plan and implement community change projects. The youth curriculum is organized around six themed units: (a) Youth as Leaders, (b) Learning about Our Community, (c) Improving Our Community, (d) Building Intergenerational Partnerships, (e) Planning for Change, and (f) Action and Reflection. The curriculum was developed through an iterative process. Initially, program staff members documented their activities with youth. These outlines were formalized as curriculum sessions. Each session was reviewed by the program and research staff and revised based on underlying theory and practical application. The curriculum process evaluation includes staff and youth feedback. This theoretically based, field-tested curriculum is designed to be easily adapted and implemented in a diverse range of communities. PMID:21059871

  7. A Finite Element Based Constrained Mixture Implementation for Arterial Growth, Remodeling, and Adaptation: Theory and Numerical Verification

    PubMed Central

    Valentín, A.; Humphrey, J. D.; Holzapfel, G. A.

    2013-01-01

    We implemented a constrained mixture model of arterial growth and remodeling (G&R) in a nonlinear finite element framework to facilitate numerical analyses of diverse cases of arterial adaptation and maladaptation, including disease progression, resulting in complex evolving geometries and compositions. This model enables hypothesis testing by predicting consequences of postulated characteristics of cell and matrix turnover, including evolving quantities and orientations of fibrillar constituents and non-homogenous degradation of elastin or loss of smooth muscle function. The non-linear finite element formulation is general within the context of arterial mechanics, but we restricted our present numerical verification to cylindrical geometries to allow comparisons to prior results for two special cases: uniform transmural changes in mass and differential G&R within a two-layered cylindrical model of the human aorta. The present finite element model recovers the results of these simplified semi-inverse analyses with good agreement. PMID:23713058

  8. Adaptation Reactions of Siderophilic Cyanobacteria to High and Low Levels Of Environmental Iron: Implications for Biosphere History

    NASA Technical Reports Server (NTRS)

    Brown, I. I.; Bryant, D.; Sarkisova, S.; Shen, G.; Garrison, D.; McKay, D. S.

    2009-01-01

    Of all extant environments, iron-depositing hot springs may constitute the most appropriate natural models (Pierson and Parenteau, 2000) for analysis of the ecophysiology of ancient cyanobacteria (CB) which may have emerged in association with hydrothermal activity (Brown et al., 2007) and elevated levels of environmental Fe (Rouxel et al., 2005). Elevated environmental Fe2+ posed a significant challenge to the first oxygenic phototrophs - CB - because reduced Fe2+ induces toxic Fenton reactions (Wiedenheft et al., 2005). Ancient CB could have also been stressed by occasional migrations from the Fe2+-rich Ocean to the basaltic land which was almost devoid of dissolved Fe2+. That is why the study of the adaptation reactions of siderophilic CB, which inhabit iron-depositing hot springs, to up and down shifts in levels of dissolved Fe may shed light on the paleophysiology of ancient oxygenic prokaryotes. Methods. Siderophilic CB (Brown et al., 2007) were cultivated in media with different concentrations of added Fe3+. In some cases basaltic rocks were used as a source of Fe and trace elements. The processes of Fe mineralization and rock dissolution were studied using TEM, SEM and EDS techniques. Fluorescence spectroscopy was used for checking chlorophyll-protein complexes. Results. It was found that five siderophilic isolates Chroogloeocystis siderophila, JSC-1, JSC-3, JSC-11 and JSC-12 precipitated Fe-bearing phases on the exopolymeric sheaths of their cells if [Fe3+] was approx. 400-600 M (high Fe). Same [Fe3+] was most optimal one for the cultures proliferation rate (Brown et al., 2005; Brown et al., 2007). Higher concentrations of Fe3+ repressed the growth of some siderophilic CB (Brown et al., 2005). No mineralized Fe3+ was observed on the sheath of freshwater isolates Synechocystis sp. PCC 6803 and Phormidium aa. Scanning TEM in conjunction with thin-window energy dispersive X-ray spectroscopy (EDS) revealed intracellular Fe-rich phases within all three isolates

  9. In-Class Examinations in College-Level Science: New Theory, New Practice.

    ERIC Educational Resources Information Center

    Tobias, Sheila; Raphael, Jacqueline B.

    1996-01-01

    Discusses innovations in testing methods in college-level science. Highlights previous efforts at reform, new thinking, new practices, and computer-generated exams and scoring systems. Reports on focus group interviews that explore student recollections of in-class examinations in college-level science. (24 references) (JRH)

  10. Leadership in Sport: The Situational Leadership Theory.

    ERIC Educational Resources Information Center

    Case, Robert W.

    1984-01-01

    Situational leadership theory suggests that to reach maximum leadership effectiveness, the leader must adapt his/her behavior to different situations. For athletic coaches, this means that the amount of direction provided for students should increase or decrease according to the students' maturity levels. Applications of the theory are discussed.…

  11. The process of adaptation of a community-level, evidence-based intervention for HIV-positive African American men who have sex with men in two cities.

    PubMed

    Robinson, Beatrice E; Galbraith, Jennifer S; Lund, Sharon M; Hamilton, Autumn R; Shankle, Michael D

    2012-06-01

    We describe the process of adapting a community-level, evidence-based behavioral intervention (EBI), Community PROMISE, for HIV-positive African American men who have sex with men (AAMSM). The Centers for Disease Control and Prevention (CDC) Map of the Adaptation Process (MAP) guided the adaptation process for this new target population by two community-based organizations (CBOs) working in partnership with two research organizations. We describe five steps of the MAP, assessment, selection, preparation, pilot, and implementation, and the use of qualitative interviews, field observations, and a cross-sectional survey. We recommend: (1) development of a centralized interactive website, listserv, or other resources where agencies adapting EBIs can share tools, materials, experiences, lessons learned, and best practices; (2) strengthening Funding Opportunity Announcements by funding incrementally in phases linked to the MAP; and (3) research should examine (a) whether EBIs adapted by CBOs remain efficacious and (b) the best "fit" between the cultural and climate characteristics of effective collaborations between community- and research-based organizations. PMID:22676461

  12. Theory of agent-based market models with controlled levels of greed and anxiety

    NASA Astrophysics Data System (ADS)

    Papadopoulos, P.; Coolen, A. C. C.

    2010-01-01

    We use generating functional analysis to study minority-game-type market models with generalized strategy valuation updates that control the psychology of agents' actions. The agents' choice between trend-following and contrarian trading, and their vigor in each, depends on the overall state of the market. Even in 'fake history' models, the theory now involves an effective overall bid process (coupled to the effective agent process) which can exhibit profound remanence effects and new phase transitions. For some models the bid process can be solved directly, others require Maxwell-construction-type approximations.

  13. Search for grand-unified-theory magnetic monopoles at a flux level below the Parker limit

    NASA Astrophysics Data System (ADS)

    Price, P. B.; Guo, S.-L.; Ahlen, S. P.; Fleischer, R. L.

    1984-04-01

    Results are presented from the first directs search for grand-unified-theory magnetic monopoles with adequate sensitivity to detect a flux as small as the Parker flux (Turner et al., 1983). It is pointed out that if stable monopole-nucleus bound states exist, then the observed absence of monopole tracks in the 4.6 x 10 to the 8th-yr-old mica detector places an upper limit of 10 to the -17th to 10 to the-16th/sq cm-sr-sec on the flux of grand-unified-theory monopoles having a velocity of 3 x 10 to the -4th c to 1.5 x 10 to the -3rd c. The scenario treated here has four aspects. The first is that monopoles enter the earth's atmosphere with a net electric charge less than or equal to zero. The second is that as the monopoles pass through the earth they eventually capture nuclei in bound states through magnetic dipole-magnetic monopole interaction. The third is that the nucleus-monopole composite passes through a naturally occurring underground sample of muscovite mica, undergoing elastic nuclear collisions that result in the formation of a trail of lattice defects in the mica. The fourth is that the track survives as long as the mica remains unheated and may be enlarged to macroscopic dimensions by retrieving the mica and etching it in hydrofluoric acid.

  14. Analytic first derivatives for a spin-adapted open-shell coupled cluster theory: Evaluation of first-order electrical properties

    SciTech Connect

    Datta, Dipayan Gauss, Jürgen

    2014-09-14

    An analytic scheme is presented for the evaluation of first derivatives of the energy for a unitary group based spin-adapted coupled cluster (CC) theory, namely, the combinatoric open-shell CC (COSCC) approach within the singles and doubles approximation. The widely used Lagrange multiplier approach is employed for the derivation of an analytical expression for the first derivative of the energy, which in combination with the well-established density-matrix formulation, is used for the computation of first-order electrical properties. Derivations of the spin-adapted lambda equations for determining the Lagrange multipliers and the expressions for the spin-free effective density matrices for the COSCC approach are presented. Orbital-relaxation effects due to the electric-field perturbation are treated via the Z-vector technique. We present calculations of the dipole moments for a number of doublet radicals in their ground states using restricted open-shell Hartree-Fock (ROHF) and quasi-restricted HF (QRHF) orbitals in order to demonstrate the applicability of our analytic scheme for computing energy derivatives. We also report calculations of the chlorine electric-field gradients and nuclear quadrupole-coupling constants for the CCl, CH{sub 2}Cl, ClO{sub 2}, and SiCl radicals.

  15. Energy level alignment and quantum conductance of functionalized metal-molecule junctions: Density functional theory versus GW calculations

    SciTech Connect

    Jin, Chengjun; Markussen, Troels; Thygesen, Kristian S.; Strange, Mikkel; Solomon, Gemma C.

    2013-11-14

    We study the effect of functional groups (CH{sub 3}*4, OCH{sub 3}, CH{sub 3}, Cl, CN, F*4) on the electronic transport properties of 1,4-benzenediamine molecular junctions using the non-equilibrium Green function method. Exchange and correlation effects are included at various levels of theory, namely density functional theory (DFT), energy level-corrected DFT (DFT+Σ), Hartree-Fock and the many-body GW approximation. All methods reproduce the expected trends for the energy of the frontier orbitals according to the electron donating or withdrawing character of the substituent group. However, only the GW method predicts the correct ordering of the conductance amongst the molecules. The absolute GW (DFT) conductance is within a factor of two (three) of the experimental values. Correcting the DFT orbital energies by a simple physically motivated scissors operator, Σ, can bring the DFT conductances close to experiments, but does not improve on the relative ordering. We ascribe this to a too strong pinning of the molecular energy levels to the metal Fermi level by DFT which suppresses the variation in orbital energy with functional group.

  16. The Design, Implementation and Evaluation of a Pilot Scheme Adapted to the Bologna Goals at Tertiary Level

    ERIC Educational Resources Information Center

    Sanchez, Purificacion

    2009-01-01

    The Bologna Declaration attempts to reform the structure of the higher education system in forty-six European countries in a convergent way. By 2010, the European space for higher education should be completed. In the 2005-2006 academic year, the University of Murcia, Spain, started promoting initiatives to adapt individual modules and entire…

  17. Assessing Levels of Adaptation during Implementation of Evidence-Based Interventions: Introducing the Rogers-Rutten Framework

    ERIC Educational Resources Information Center

    Bowen, Shelly-Ann K.; Saunders, Ruth P.; Richter, Donna L.; Hussey, Jim; Elder, Keith; Lindley, Lisa

    2010-01-01

    Most HIV-prevention funding agencies require the use of evidence-based behavioral interventions, tested and proven to be effective through outcome evaluation. Adaptation of programs during implementation is common and may be influenced by many factors, including agency mission, time constraints, and funding streams. There are few theoretical…

  18. An Evaluation of Levels of Adaptation Used in the Teaching of Foreign University Degree Programs in China

    ERIC Educational Resources Information Center

    Willis, Mike

    2004-01-01

    Many universities now deliver courses and programs in overseas markets such as China. Often these programs are delivered by foreign academics who teach in these overseas locations. This style and format of educational delivery raises the issue of the degree to which subject material and teaching styles need to be adapted to meet the needs of…

  19. Longitudinal study of cognitive abilities and adaptive behavior levels in fragile X males: a prospective multicenter analysis.

    PubMed

    Fisch, G S; Simensen, R; Tarleton, J; Chalifoux, M; Holden, J J; Carpenter, N; Howard-Peebles, P N; Maddalena, A

    1996-08-01

    Retrospective longitudinal studies have noted declines in IQ scores in many but not all fra(X) (fragile X) males and females. We report on a prospective investigation of longitudinal changes in cognitive ability (IQ) and adaptive behavior (DQ) in 24 fra(X) males from four test sites. Individuals who were tested ranged in age from 3-15 years. To determine cognitive ability, all males were administered the Stanford-Binet test (4th Edition). To assess adaptive behavior, all males were evaluated using the Vineland Adaptive Behavior Scales. Mean interest interval was 2.3 years. Using identical DNA protocols, all subjects were identified as bearing the fra(X) mutation. Results showed declines in IQ scores in 18/24 (75%) males. Four males showed no change in scores. Declines in DQ scores were noted in 22/24 (92%) of those tested. DQ scores were higher than IQ scores in 20/24 (83%) subjects. From a descriptive cohort analysis, decreases in IQ scores appear to follow a well-defined, negatively decelerating function. Declines in DQ were steeper and more nearly linear. Declining scores are not indicative of regression of intellectual and/or social skills, but of a relative inability to keep pace with their age-normed cohort. We conclude that the fra(X) mutation affects cognitive abilities in a uniform, nonlinear manner comparable to outcomes observed in earlier retrospective studies. Adaptive behavior also declines, but in a more linear fashion. PMID:8844080

  20. Teaching College Level Content and Reading Comprehension Skills Simultaneously via an Artificially Intelligent Adaptive Computerized Instructional System

    ERIC Educational Resources Information Center

    Ray, Roger D.; Belden, Noelle

    2007-01-01

    This paper presents a behavioral model for conceptualizing advanced reading comprehension as a "higher order" behavior class. Also discussed are strategies and tactics utilized by an artificially intelligent adaptive tutoring and testing software system designed to shape such comprehension skills while also teaching subject-specific "content" to…

  1. The City and County of San Francisco's Approach to Sea Level Rise Science and Adaptation Planning: Creating Infrastructure Resilience from Information Chaos

    NASA Astrophysics Data System (ADS)

    Behar, D. H.; Pfeffer, W. T.; May, K.; Mote, P.; Cayan, D. R.

    2014-12-01

    During one 17 month period ending October 2013, three major reports on sea level rise from three highly respected science providers produced three differing, in some cases wildly divergent, estimates of sea level rise through the year 2100. These reports, by the National Research Council, the IPCC, and the National Climate Assessment, collectively flummoxed the lay reader seeking direction on sea level rise projections to incorporate into adaptation planning. Guidance documents soon emerged from state entities, including regulatory agencies, which caused further confusion. The City and County of San Francisco, surrounded by water on three sides, began developing City-wide sea level rise guidance in 2013. A Sea Level Rise Committee featuring representatives of key infrastructure managers met over a nine month period, and their work included an in-depth review of the science of sea level rise. To convert divergent scientific reports into "actionable science" required not only a close reading of each but extensive expert elicitation to tease out the meaning behind each of the numbers and the associated uncertainties. In the end, sufficient consistency between the differing projections, fortified by political exigencies, allowed a "scientific consensus" with actionable science value for the City to surface. The resulting document, "Guidance for Incorporating Sea Level Rise into Capital Planning in San Francisco," begins by providing a scientific underpinning for planning, guidelines for incorporating uncertainty - particularly for accommodating multiple projections for any particular time slice - and outlines a four step process for assessment and adaptation. It also relies on new state-of-the-art inundation maps produced as part of the SFPUC's capital improvement program. Together, the Guidance and associated tools provide a road map for successful assessment and adaptation to sea level rise. We will also draw lessons from the experience that may be of value to

  2. Creating Infrastructure Resilience from Information Chaos: The City and County of San Francisco's Approach to Sea Level Rise Science and Adaptation Planning

    NASA Astrophysics Data System (ADS)

    Behar, D. H.; Pfeffer, W. T.; May, K.; Mote, P.; Cayan, D. R.

    2014-12-01

    During one 17 month period ending October 2013, three major reports on sea level rise from three highly respected science providers produced three differing, in some cases wildly divergent, estimates of sea level rise through the year 2100. These reports, by the National Research Council, the IPCC, and the National Climate Assessment, collectively flummoxed the lay reader seeking direction on sea level rise projections to incorporate into adaptation planning. Guidance documents soon emerged from state entities, including regulatory agencies, which caused further confusion. The City and County of San Francisco, surrounded by water on three sides, began developing City-wide sea level rise guidance in 2013. A Sea Level Rise Committee featuring representatives of key infrastructure managers met over a nine month period, and their work included an in-depth review of the science of sea level rise. To convert divergent scientific reports into "actionable science" required not only a close reading of each but extensive expert elicitation to tease out the meaning behind each of the numbers and the associated uncertainties. In the end, sufficient consistency between the differing projections, fortified by political exigencies, allowed a "scientific consensus" with actionable science value for the City to surface. The resulting document, "Guidance for Incorporating Sea Level Rise into Capital Planning in San Francisco," begins by providing a scientific underpinning for planning, guidelines for incorporating uncertainty - particularly for accommodating multiple projections for any particular time slice - and outlines a four step process for assessment and adaptation. It also relies on new state-of-the-art inundation maps produced as part of the SFPUC's capital improvement program. Together, the Guidance and associated tools provide a road map for successful assessment and adaptation to sea level rise. We will also draw lessons from the experience that may be of value to

  3. Coupled sensor/platform control design for low-level chemical detection with position-adaptive micro-UAVs

    NASA Astrophysics Data System (ADS)

    Goodwin, Thomas; Carr, Ryan; Mitra, Atindra K.; Selmic, Rastko R.

    2009-05-01

    We discuss the development of Position-Adaptive Sensors [1] for purposes for detecting embedded chemical substances in challenging environments. This concept is a generalization of patented Position-Adaptive Radar Concepts developed at AFRL for challenging conditions such as urban environments. For purposes of investigating the detection of chemical substances using multiple MAV (Micro-UAV) platforms, we have designed and implemented an experimental testbed with sample structures such as wooden carts that contain controlled leakage points. Under this general concept, some of the members of a MAV swarm can serve as external position-adaptive "transmitters" by blowing air over the cart and some of the members of a MAV swarm can serve as external position-adaptive "receivers" that are equipped with chemical or biological (chem/bio) sensors that function as "electronic noses". The objective can be defined as improving the particle count of chem/bio concentrations that impinge on a MAV-based position-adaptive sensor that surrounds a chemical repository, such as a cart, via the development of intelligent position-adaptive control algorithms. The overall effect is to improve the detection and false-alarm statistics of the overall system. Within the major sections of this paper, we discuss a number of different aspects of developing our initial MAV-Based Sensor Testbed. This testbed includes blowers to simulate position-adaptive excitations and a MAV from Draganfly Innovations Inc. with stable design modifications to accommodate our chem/bio sensor boom design. We include details with respect to several critical phases of the development effort including development of the wireless sensor network and experimental apparatus, development of the stable sensor boom for the MAV, integration of chem/bio sensors and sensor node onto the MAV and boom, development of position-adaptive control algorithms and initial tests at IDCAST (Institute for the Development and

  4. Adapting Poisson-Boltzmann to the self-consistent mean field theory: Application to protein side-chain modeling

    NASA Astrophysics Data System (ADS)

    Koehl, Patrice; Orland, Henri; Delarue, Marc

    2011-08-01

    We present an extension of the self-consistent mean field theory for protein side-chain modeling in which solvation effects are included based on the Poisson-Boltzmann (PB) theory. In this approach, the protein is represented with multiple copies of its side chains. Each copy is assigned a weight that is refined iteratively based on the mean field energy generated by the rest of the protein, until self-consistency is reached. At each cycle, the variational free energy of the multi-copy system is computed; this free energy includes the internal energy of the protein that accounts for vdW and electrostatics interactions and a solvation free energy term that is computed using the PB equation. The method converges in only a few cycles and takes only minutes of central processing unit time on a commodity personal computer. The predicted conformation of each residue is then set to be its copy with the highest weight after convergence. We have tested this method on a database of hundred highly refined NMR structures to circumvent the problems of crystal packing inherent to x-ray structures. The use of the PB-derived solvation free energy significantly improves prediction accuracy for surface side chains. For example, the prediction accuracies for χ1 for surface cysteine, serine, and threonine residues improve from 68%, 35%, and 43% to 80%, 53%, and 57%, respectively. A comparison with other side-chain prediction algorithms demonstrates that our approach is consistently better in predicting the conformations of exposed side chains.

  5. Computational aspects of helicopter trim analysis and damping levels from Floquet theory

    NASA Technical Reports Server (NTRS)

    Gaonkar, Gopal H.; Achar, N. S.

    1992-01-01

    Helicopter trim settings of periodic initial state and control inputs are investigated for convergence of Newton iteration in computing the settings sequentially and in parallel. The trim analysis uses a shooting method and a weak version of two temporal finite element methods with displacement formulation and with mixed formulation of displacements and momenta. These three methods broadly represent two main approaches of trim analysis: adaptation of initial-value and finite element boundary-value codes to periodic boundary conditions, particularly for unstable and marginally stable systems. In each method, both the sequential and in-parallel schemes are used and the resulting nonlinear algebraic equations are solved by damped Newton iteration with an optimally selected damping parameter. The impact of damped Newton iteration, including earlier-observed divergence problems in trim analysis, is demonstrated by the maximum condition number of the Jacobian matrices of the iterative scheme and by virtual elimination of divergence. The advantages of the in-parallel scheme over the conventional sequential scheme are also demonstrated.

  6. Computer simulation and high level virial theory of Saturn-ring or UFO colloids.

    PubMed

    Bates, Martin A; Dennison, Matthew; Masters, Andrew

    2008-08-21

    Monte Carlo simulations are used to map out the complete phase diagram of hard body UFO systems, in which the particles are composed of a concentric sphere and thin disk. The equation of state and phase behavior are determined for a range of relative sizes of the sphere and disk. We show that for relatively large disks, nematic and solid phases are observed in addition to the isotropic fluid. For small disks, two different solid phases exist. For intermediate sizes, only a disordered fluid phase is observed. The positional and orientational structure of the various phases are examined. We also compare the equations of state and the nematic-isotropic coexistence densities with those predicted by an extended Onsager theory using virial coefficients up to B(8). PMID:19044798

  7. Computer simulation and high level virial theory of Saturn-ring or UFO colloids

    NASA Astrophysics Data System (ADS)

    Bates, Martin A.; Dennison, Matthew; Masters, Andrew

    2008-08-01

    Monte Carlo simulations are used to map out the complete phase diagram of hard body UFO systems, in which the particles are composed of a concentric sphere and thin disk. The equation of state and phase behavior are determined for a range of relative sizes of the sphere and disk. We show that for relatively large disks, nematic and solid phases are observed in addition to the isotropic fluid. For small disks, two different solid phases exist. For intermediate sizes, only a disordered fluid phase is observed. The positional and orientational structure of the various phases are examined. We also compare the equations of state and the nematic-isotropic coexistence densities with those predicted by an extended Onsager theory using virial coefficients up to B8.

  8. Decision Level Fusion of LIDAR Data and Aerial Color Imagery Based on Bayesian Theory for Urban Area Classification

    NASA Astrophysics Data System (ADS)

    Rastiveis, H.

    2015-12-01

    Airborne Light Detection and Ranging (LiDAR) generates high-density 3D point clouds to provide a comprehensive information from object surfaces. Combining this data with aerial/satellite imagery is quite promising for improving land cover classification. In this study, fusion of LiDAR data and aerial imagery based on Bayesian theory in a three-level fusion algorithm is presented. In the first level, pixel-level fusion, the proper descriptors for both LiDAR and image data are extracted. In the next level of fusion, feature-level, using extracted features the area are classified into six classes of "Buildings", "Trees", "Asphalt Roads", "Concrete roads", "Grass" and "Cars" using Naïve Bayes classification algorithm. This classification is performed in three different strategies: (1) using merely LiDAR data, (2) using merely image data, and (3) using all extracted features from LiDAR and image. The results of three classifiers are integrated in the last phase, decision level fusion, based on Naïve Bayes algorithm. To evaluate the proposed algorithm, a high resolution color orthophoto and LiDAR data over the urban areas of Zeebruges, Belgium were applied. Obtained results from the decision level fusion phase revealed an improvement in overall accuracy and kappa coefficient.

  9. Road Extraction Method At The Pixel And Object Level Using High Resolution Images And LIDAR Data With Evidence Theory

    NASA Astrophysics Data System (ADS)

    Rodriguez-Cuenca, Borja; Martinez de Agirre, Alex; Alonso, Maria Concepcion; del Val, Alberto

    2013-12-01

    Light Detection and Ranging (LIDAR) data provides accurate height information for objects on the Earth's surface. It is common to combine LIDAR data with satellite or aerial imagery to determine the location of different cartographic entities. In this work, an automated method for road extraction in urban areas from high resolution aerial images is presented. This method is based on the Dempster-Shafer Theory of evidence, which consists of fusing information from different information sources. The proposed method is applied to road extraction in two different ways: at the pixel level and at the object level. The results provided for both levels are compared with a ground truth created by the authors of this work in order to determine which method provides the best accuracy.

  10. Using the Ultimatum Game to Teach Economic Theories of Relationship Maintenance to A-Level Students

    ERIC Educational Resources Information Center

    Knight, Simon

    2011-01-01

    When teaching at A-level, educators often present a model of psychology that does not extend beyond the confines of the specification. However, sometimes not only is it possible to provide insight into other areas of psychology, it provides a novel way of understanding a concept included in the specification itself. By extending student's…

  11. Bioecological Theory, Early Child Development and the Validation of the Population-Level Early Development Instrument

    ERIC Educational Resources Information Center

    Guhn, Martin; Goelman, Hillel

    2011-01-01

    The Early Development Instrument (EDI; Janus and Offord in "Canadian Journal of Behavioural Science" 39:1-22, 2007) project is a Canadian population-level, longitudinal research project, in which teacher ratings of Kindergarten children's early development and wellbeing are linked to health and academic achievement variables at the individual…

  12. The Way Ahead for Finnish Comprehensive School? Examining State-Level School Administrators' Theory of Change

    ERIC Educational Resources Information Center

    Salonen-Hakomäki, Sanna-Mari; Soini, Tiina; Pietarinen, Janne; Pyhältö, Kirsi

    2016-01-01

    A significant body of evidence shows that the goals of educational reforms are seldom fully achieved. Some research suggests that the problem lies in state-level curriculum reform work that lacks a sufficient understanding of the educational reality. However, views and perceptions among the central architects of the reforms have not been…

  13. Adaptive particle-based pore-level modeling of incompressible fluid flow in porous media: a direct and parallel approach

    NASA Astrophysics Data System (ADS)

    Ovaysi, S.; Piri, M.

    2009-12-01

    We present a three-dimensional fully dynamic parallel particle-based model for direct pore-level simulation of incompressible viscous fluid flow in disordered porous media. The model was developed from scratch and is capable of simulating flow directly in three-dimensional high-resolution microtomography images of naturally occurring or man-made porous systems. It reads the images as input where the position of the solid walls are given. The entire medium, i.e., solid and fluid, is then discretized using particles. The model is based on Moving Particle Semi-implicit (MPS) technique. We modify this technique in order to improve its stability. The model handles highly irregular fluid-solid boundaries effectively. It takes into account viscous pressure drop in addition to the gravity forces. It conserves mass and can automatically detect any false connectivity with fluid particles in the neighboring pores and throats. It includes a sophisticated algorithm to automatically split and merge particles to maintain hydraulic connectivity of extremely narrow conduits. Furthermore, it uses novel methods to handle particle inconsistencies and open boundaries. To handle the computational load, we present a fully parallel version of the model that runs on distributed memory computer clusters and exhibits excellent scalability. The model is used to simulate unsteady-state flow problems under different conditions starting from straight noncircular capillary tubes with different cross-sectional shapes, i.e., circular/elliptical, square/rectangular and triangular cross-sections. We compare the predicted dimensionless hydraulic conductances with the data available in the literature and observe an excellent agreement. We then test the scalability of our parallel model with two samples of an artificial sandstone, samples A and B, with different volumes and different distributions (non-uniform and uniform) of solid particles among the processors. An excellent linear scalability is

  14. The correlation of sodium and potassium metabolism with the level of energy consumption in man during adaptation to heat

    NASA Technical Reports Server (NTRS)

    Afanasyev, B. G.; Zhestovskiy, V. A.

    1978-01-01

    The sodium and potassium metabolism was studied in a thermal chamber at 35 deg and 80 percent relative humidity in 8 men for a period of 6 days. The control group (3 subjects) were outside of the chamber at a comfortable ambient temperature. The intracellular sodium and potassium metabolism were assessed based on their content in the erythrocytes. The finding was that during adaptation to heat, a considerable amount of sodium was excreted by the body in the sweat and urine (about 1/3 of the sodium content of the human body) as compared with its intake and the amount of potassium retained in the body. Changes in the concentration of sodium and potassium may serve as indexes of the state of adaptation processes during constant exposure to heat.

  15. The IUPAC Database of Rotational-Vibrational Energy Levels and Transitions of Water Isotopologues from Experiment and Theory

    NASA Astrophysics Data System (ADS)

    Császár, Attila G.; Furtenbacher, T.; Tennyson, Jonathan; Bernath, Peter F.; Brown, Linda R.; Campargue, Alain; Daumont, Ludovic; Gamache, Robert R.; Hodges, Joseph T.; Naumenko, Olga V.; Polyansky, Oleg L.; Rothman, Laurence S.; Vandaele, Ann Carine; Zobov, Nikolai F.

    2014-06-01

    The results of an IUPAC Task Group formed in 2004 on "A Database of Water Transitions from Experiment and Theory" (Project No. 2004-035-1-100) are presented. Energy levels and recommended labels involving exact and approximate quantum numbers for the main isotopologues of water in the gas phase, H216O, H218O, H217O, HD16O, HD18O, HD17O, D216O, D218O, and D217O, are determined from measured transition wavenumbers. The transition wavenumbers and energy levels are validated using the MARVEL (measured active rotational-vibrational energy levels) approach and first-principles nuclear motion computations. The extensive data, e.g., more than 200,000 transitions have been handled for H216O, including lines and levels that are required for analysis and synthesis of spectra, thermochemical applications, the construction of theoretical models, and the removal of spectral contamination by ubiquitous water lines. These datasets can also be used to assess where measurements are lacking for each isotopologue and to provide accurate frequencies for many yet-to-be measured transitions. The lack of high-quality frequency calibration standards in the near infrared is identified as an issue that has hindered the determination of high-accuracy energy levels at higher frequencies. The generation of spectra using the MARVEL energy levels combined with transition intensities computed using high accuracy ab initio dipole moment surfaces are discussed.

  16. Parallel implementation of multireference coupled-cluster theories based on the reference-level parallelism

    SciTech Connect

    Brabec, Jiri; Pittner, Jiri; van Dam, Hubertus JJ; Apra, Edoardo; Kowalski, Karol

    2012-02-01

    A novel algorithm for implementing general type of multireference coupled-cluster (MRCC) theory based on the Jeziorski-Monkhorst exponential Ansatz [B. Jeziorski, H.J. Monkhorst, Phys. Rev. A 24, 1668 (1981)] is introduced. The proposed algorithm utilizes processor groups to calculate the equations for the MRCC amplitudes. In the basic formulation each processor group constructs the equations related to a specific subset of references. By flexible choice of processor groups and subset of reference-specific sufficiency conditions designated to a given group one can assure optimum utilization of available computing resources. The performance of this algorithm is illustrated on the examples of the Brillouin-Wigner and Mukherjee MRCC methods with singles and doubles (BW-MRCCSD and Mk-MRCCSD). A significant improvement in scalability and in reduction of time to solution is reported with respect to recently reported parallel implementation of the BW-MRCCSD formalism [J.Brabec, H.J.J. van Dam, K. Kowalski, J. Pittner, Chem. Phys. Lett. 514, 347 (2011)].

  17. Comparative Genomics Analysis of Streptomyces Species Reveals Their Adaptation to the Marine Environment and Their Diversity at the Genomic Level

    PubMed Central

    Tian, Xinpeng; Zhang, Zhewen; Yang, Tingting; Chen, Meili; Li, Jie; Chen, Fei; Yang, Jin; Li, Wenjie; Zhang, Bing; Zhang, Zhang; Wu, Jiayan; Zhang, Changsheng; Long, Lijuan; Xiao, Jingfa

    2016-01-01

    Over 200 genomes of streptomycete strains that were isolated from various environments are available from the NCBI. However, little is known about the characteristics that are linked to marine adaptation in marine-derived streptomycetes. The particularity and complexity of the marine environment suggest that marine streptomycetes are genetically diverse. Here, we sequenced nine strains from the Streptomyces genus that were isolated from different longitudes, latitudes, and depths of the South China Sea. Then we compared these strains to 22 NCBI downloaded streptomycete strains. Thirty-one streptomycete strains are clearly grouped into a marine-derived subgroup and multiple source subgroup-based phylogenetic tree. The phylogenetic analyses have revealed the dynamic process underlying streptomycete genome evolution, and lateral gene transfer is an important driving force during the process. Pan-genomics analyses have revealed that streptomycetes have an open pan-genome, which reflects the diversity of these streptomycetes and guarantees the species a quick and economical response to diverse environments. Functional and comparative genomics analyses indicate that the marine-derived streptomycetes subgroup possesses some common characteristics of marine adaptation. Our findings have expanded our knowledge of how ocean isolates of streptomycete strains adapt to marine environments. The availability of streptomycete genomes from the South China Sea will be beneficial for further analysis on marine streptomycetes and will enrich the South China Sea’s genetic data sources. PMID:27446038

  18. Comparative Genomics Analysis of Streptomyces Species Reveals Their Adaptation to the Marine Environment and Their Diversity at the Genomic Level.

    PubMed

    Tian, Xinpeng; Zhang, Zhewen; Yang, Tingting; Chen, Meili; Li, Jie; Chen, Fei; Yang, Jin; Li, Wenjie; Zhang, Bing; Zhang, Zhang; Wu, Jiayan; Zhang, Changsheng; Long, Lijuan; Xiao, Jingfa

    2016-01-01

    Over 200 genomes of streptomycete strains that were isolated from various environments are available from the NCBI. However, little is known about the characteristics that are linked to marine adaptation in marine-derived streptomycetes. The particularity and complexity of the marine environment suggest that marine streptomycetes are genetically diverse. Here, we sequenced nine strains from the Streptomyces genus that were isolated from different longitudes, latitudes, and depths of the South China Sea. Then we compared these strains to 22 NCBI downloaded streptomycete strains. Thirty-one streptomycete strains are clearly grouped into a marine-derived subgroup and multiple source subgroup-based phylogenetic tree. The phylogenetic analyses have revealed the dynamic process underlying streptomycete genome evolution, and lateral gene transfer is an important driving force during the process. Pan-genomics analyses have revealed that streptomycetes have an open pan-genome, which reflects the diversity of these streptomycetes and guarantees the species a quick and economical response to diverse environments. Functional and comparative genomics analyses indicate that the marine-derived streptomycetes subgroup possesses some common characteristics of marine adaptation. Our findings have expanded our knowledge of how ocean isolates of streptomycete strains adapt to marine environments. The availability of streptomycete genomes from the South China Sea will be beneficial for further analysis on marine streptomycetes and will enrich the South China Sea's genetic data sources. PMID:27446038

  19. Relativistic Many-body Moller-Plesset Perturbation Theory Calculations of the Energy Levels and Transition Probabilities in Na- to P-like Xe Ions

    SciTech Connect

    Vilkas, M J; Ishikawa, Y; Trabert, E

    2007-03-27

    Relativistic multireference many-body perturbation theory calculations have been performed on Xe{sup 43+}-Xe{sup 39+} ions, resulting in energy levels, electric dipole transition probabilities, and level lifetimes. The second-order many-body perturbation theory calculation of energy levels included mass shifts, frequency-dependent Breit correction and Lamb shifts. The calculated transition energies and E1 transition rates are used to present synthetic spectra in the extreme ultraviolet range for some of the Xe ions.

  20. An electret model based on the two-level system theory

    NASA Astrophysics Data System (ADS)

    Gladkov, S. O.

    1990-01-01

    On the basis of the concept of a two-line density matrix and considering the tunneling effect a set of simultaneous differential equations is derived relating all its components. An equation is obtained describing the polarization vector relaxation in an electret. The relaxation parameter α corresponding to the polarization vector total relaxation time is calculated microscopically. A system of differential equations allowing for the effect on the atoms of a strongly oscillating classical electric field is proposed. An analytical formula for thermal current in an electret is obtained and the behavior of two-level systems in a high-frequency electric field is analyzed.

  1. An electret model based on the two-level system theory

    NASA Astrophysics Data System (ADS)

    Gladkov, S. O.

    1989-12-01

    On the basis of the concept of a two-line density matrix and considering the tunneling effect a set of simultaneous differential equations is derived relating all its components. An equation is obtained describing the polarization vector relaxation in an electret. The relaxation parameter α corresponding to the polarization vector total relaxation time is calculated microscopically. A system of differential equations allowing for the effect on the atoms of a strongly oscillating classical electric field is proposed. An analytical formula for thermal current in an electret is obtained and the behavior of two-level systems in a high-frequency electric field is analyzed.

  2. What range of trait levels can the Autism-Spectrum Quotient (AQ) measure reliably? An item response theory analysis.

    PubMed

    Murray, Aja Louise; Booth, Tom; McKenzie, Karen; Kuenssberg, Renate

    2016-06-01

    It has previously been noted that inventories measuring traits that originated in a psychopathological paradigm can often reliably measure only a very narrow range of trait levels that are near and above clinical cutoffs. Much recent work has, however, suggested that autism spectrum disorder traits are on a continuum of severity that extends well into the nonclinical range. This implies a need for inventories that can capture individual differences in autistic traits from very high levels all the way to the opposite end of the continuum. The Autism-Spectrum Quotient (AQ) was developed based on a closely related rationale, but there has, to date, been no direct test of the range of trait levels that the AQ can reliably measure. To assess this, we fit a bifactor item response theory model to the AQ. Results suggested that AQ measures moderately low to moderately high levels of a general autistic trait with good measurement precision. The reliable range of measurement was significantly improved by scoring the instrument using its 4-point response scale, rather than dichotomizing responses. These results support the use of the AQ in nonclinical samples, but suggest that items measuring very low and very high levels of autistic traits would be beneficial additions to the inventory. (PsycINFO Database Record PMID:26302097

  3. Theory of Mind and Executive Control Deficits in Typically Developing Adults and Adolescents with High Levels of Autism Traits.

    PubMed

    Gökçen, Elif; Frederickson, Norah; Petrides, K V

    2016-06-01

    Autism spectrum disorder (ASD) is characterised by profound difficulties in empathic processing and executive control. Whilst the links between these processes have been frequently investigated in populations with autism, few studies have examined them at the subclinical level. In addition, the contribution of alexithymia, a trait characterised by impaired interoceptive awareness and empathy, and elevated in those with ASD, is currently unclear. The present two-part study employed a comprehensive battery of tasks to examine these processes. Findings support the notion that executive function and theory of mind are related abilities. They also suggest that individuals with elevated levels of autism-like traits experience a partially similar pattern of social and executive function difficulties to those diagnosed with ASD, and that these impairments are not explained by co-occurring alexithymia. PMID:26886468

  4. The relationship between human resource investments and organizational performance: a firm-level examination of equilibrium theory.

    PubMed

    Subramony, Mahesh; Krause, Nicole; Norton, Jacqueline; Burns, Gary N

    2008-07-01

    It is commonly believed that human resource investments can yield positive performance-related outcomes for organizations. Utilizing the theory of organizational equilibrium (H. A. Simon, D. W. Smithburg, & V. A. Thompson, 1950; J. G. March & H. A. Simon, 1958), the authors proposed that organizational inducements in the form of competitive pay will lead to 2 firm-level performance outcomes--labor productivity and customer satisfaction--and that financially successful organizations would be more likely to provide these inducements to their employees. To test their hypotheses, the authors gathered employee-survey and objective performance data from a sample of 126 large publicly traded U.S. organizations over a period of 3 years. Results indicated that (a) firm-level financial performance (net income) predicted employees' shared perceptions of competitive pay, (b) shared pay perceptions predicted future labor productivity, and (c) the relationship between shared pay perceptions and customer satisfaction was fully mediated by employee morale. PMID:18642983

  5. Investigation of the features of polycrystals complex loading using a two-level crystal plasticity theory

    NASA Astrophysics Data System (ADS)

    Volegov, P. S.; Trusov, P. V.; Gribov, D. S.

    2015-01-01

    The article considers a two-level mathematical model of inelastic deformation of metal polycrystals taking into account evolution of the structure. The structure of the model was considered, some special features of its application to describe the intensity of inelastic deformations were marked. The need for a careful physical analysis of the hardening laws construction was highlighted. To evaluate the applicability of multi-level models to describe the known experimental effects of cyclic deformation a number of results of field experiments on the complex proportional and disproportional cyclic deformation was considered, some specific effects that appear in these processes were identified: stresses amplitude output at the stationary value; additional cyclic hardening at a disproportionate loading, which magnitude depends on the so-called degree of disproportionality. Numerical experiments on the disproportionate cyclic loading were carried out, the possibility of modified hardening laws to describe access to the stationary values of the stress intensity was noted, and also the possibility of a qualitative description of the effect of additional cyclic hardening was demonstrated. The A.A. Ilyushin hypothesis by isotropy and the principle of vector properties delay at the turn of the deformation path were validated.

  6. Time-optimal path planning in dynamic flows using level set equations: theory and schemes

    NASA Astrophysics Data System (ADS)

    Lolla, Tapovan; Lermusiaux, Pierre F. J.; Ueckermann, Mattheus P.; Haley, Patrick J.

    2014-09-01

    We develop an accurate partial differential equation-based methodology that predicts the time-optimal paths of autonomous vehicles navigating in any continuous, strong, and dynamic ocean currents, obviating the need for heuristics. The goal is to predict a sequence of steering directions so that vehicles can best utilize or avoid currents to minimize their travel time. Inspired by the level set method, we derive and demonstrate that a modified level set equation governs the time-optimal path in any continuous flow. We show that our algorithm is computationally efficient and apply it to a number of experiments. First, we validate our approach through a simple benchmark application in a Rankine vortex flow for which an analytical solution is available. Next, we apply our methodology to more complex, simulated flow fields such as unsteady double-gyre flows driven by wind stress and flows behind a circular island. These examples show that time-optimal paths for multiple vehicles can be planned even in the presence of complex flows in domains with obstacles. Finally, we present and support through illustrations several remarks that describe specific features of our methodology.

  7. Time-optimal path planning in dynamic flows using level set equations: theory and schemes

    NASA Astrophysics Data System (ADS)

    Lolla, Tapovan; Lermusiaux, Pierre F. J.; Ueckermann, Mattheus P.; Haley, Patrick J.

    2014-10-01

    We develop an accurate partial differential equation-based methodology that predicts the time-optimal paths of autonomous vehicles navigating in any continuous, strong, and dynamic ocean currents, obviating the need for heuristics. The goal is to predict a sequence of steering directions so that vehicles can best utilize or avoid currents to minimize their travel time. Inspired by the level set method, we derive and demonstrate that a modified level set equation governs the time-optimal path in any continuous flow. We show that our algorithm is computationally efficient and apply it to a number of experiments. First, we validate our approach through a simple benchmark application in a Rankine vortex flow for which an analytical solution is available. Next, we apply our methodology to more complex, simulated flow fields such as unsteady double-gyre flows driven by wind stress and flows behind a circular island. These examples show that time-optimal paths for multiple vehicles can be planned even in the presence of complex flows in domains with obstacles. Finally, we present and support through illustrations several remarks that describe specific features of our methodology.

  8. Theory of the Effects of Small Gravitational Levels on Droplet Gasification

    NASA Technical Reports Server (NTRS)

    Beitelmal, A.; Shaw, B. D.

    1995-01-01

    A mathematical model taking into account small (and constant) gravitational levels is developed for vaporization of an isolated liquid droplet suspended in a stagnant atmosphere. A goal of the present analysis is to see how small gravitational levels affect droplet gasification characteristics. Attention is focused upon determining the effects on gas-phase phenomena. The conservation equations arc normalized and nondimensionalized, and a small parameter that accounts for the effects of gravity is identified. This parameter is the square of the inverse of a Froude number based on the gravitational acceleration, the droplet radius, and a characteristic gas-phase velocity at the droplet surface. Asymptotic analyses are developed in terms of this parameter. In the analyses, different spatial regions are identified. Near a droplet, gravitational effects are negligible in the first approximation, and the flowfield is spherically symmetric to the leading order. Analysis shows, however, that outer zones exist where gravitational effects cannot be neglected; it is expected that a stagnation point will be present in an outer zone that is not present when gravity is totally absent. The leading order and higher-order differential equations for each zone are derived and solved. The solutions allow the effects of gravity on vaporization rates and temperature, velocity and species fields to be determined.

  9. Crystallization in high-level waste glass: A review of glass theory and noteworthy literature

    SciTech Connect

    Christian, J. H.

    2015-08-18

    There is a fundamental need to continue research aimed at understanding nepheline and spinel crystal formation in high-level waste (HLW) glass. Specifically, the formation of nepheline solids (K/NaAlSiO4) during slow cooling of HLW glass can reduce the chemical durability of the glass, which can cause a decrease in the overall durability of the glass waste form. The accumulation of spinel solids ((Fe, Ni, Mn, Zn)(Fe, Cr)2O4), while not detrimental to glass durability, can cause an array of processing problems inside HLW glass melters. In this review, the fundamental differences between glass and solid-crystals are explained using kinetic, thermodynamic, and viscosity arguments, and several highlights of glass-crystallization research, as it pertains to high-level waste vitrification, are described. In terms of mitigating spinel in the melter and both spinel and nepheline formation in the canister, the complexity of HLW glass and the intricate interplay between thermal, chemical, and kinetic factors further complicates this understanding. However, new experiments seeking to elucidate the contributing factors of crystal nucleation and growth in waste glass, and the compilation of data from older experiments, may go a long way towards helping to achieve higher waste loadings while developing more efficient processing strategies. Higher waste loadings and more efficient processing strategies will reduce the overall HLW Hanford Tank Waste Treatment and Immobilization Plant (WTP) vitrification facilities mission life.

  10. Crystallization in high-level waste glass: A review of glass theory and noteworthy literature

    SciTech Connect

    Christian, J. H.

    2015-08-01

    There is a fundamental need to continue research aimed at understanding nepheline and spinel crystal formation in high-level waste (HLW) glass. Specifically, the formation of nepheline solids (K/NaAlSiO₄) during slow cooling of HLW glass can reduce the chemical durability of the glass, which can cause a decrease in the overall durability of the glass waste form. The accumulation of spinel solids ((Fe, Ni, Mn, Zn)(Fe,Cr)₂O₄), while not detrimental to glass durability, can cause an array of processing problems inside of HLW glass melters. In this review, the fundamental differences between glass and solid-crystals are explained using kinetic, thermodynamic, and viscosity arguments, and several highlights of glass-crystallization research, as it pertains to high-level waste vitrification, are described. In terms of mitigating spinel in the melter and both spinel and nepheline formation in the canister, the complexity of HLW glass and the intricate interplay between thermal, chemical, and kinetic factors further complicates this understanding. However, new experiments seeking to elucidate the contributing factors of crystal nucleation and growth in waste glass, and the compilation of data from older experiments, may go a long way towards helping to achieve higher waste loadings while developing more efficient processing strategies.

  11. Coping strategy in adolescents with premenstrual syndrome: application of the construal level theory and the precaution adoption process model.

    PubMed

    Delara, Mahin; Ghofranipour, Fazllollah; Fallah, Parviz Azad; Tavafian, Sedighe Sadat; Kazemnejad, Anoushirvan; Montazeri, Ali; Sani, Abolfazl Rahmani; Kooshki, Mehdi

    2013-01-01

    This study aimed to apply the construal level theory (CLT) to increase the relaxation adoption as a coping behavior in adolescents with premenstrual syndrome (PMS). The theory offers a framework that assumes decision-making about adoption of any given behavior depends on perceived temporal distance from the desired or recommended behavior and thus individual might perceive any information or intervention, at two levels (low or high). In doing so, a trial was conducted on 1578 high school students suffering from PMS. The precaution adoption process model was applied to categorize students in six stages, based on their intention to adopt a behavior. The focus of this study was on students who were in stage 3 of the model (undecided to adopt a behavior that was relaxation). Overall, 411 students were identified and randomly assigned to the three study groups: group 1 (n = 98) who received a CLT-driven intervention containing detailed information about relaxation (low-level construal, LLC); group 2 (n = 150) who received a CTL-driven intervention containing general information about relaxation (high-level construal, HLC); and group 3 (n = 163) who received nothing (control group). The progression from stage 3 toward stage 6 (action) was considered as the desired outcome and it was hypothesized that LLC intervention would be more effective than HLC intervention. Compared to participants in the control group, participants in the high and low construal groups were significantly more likely to advance to the action stage (P < 0.001). In addition, students in the low construal group had made an apparent higher stage progression as compared to the high construal group, although this difference was not statistically significant (P = 0.33). The findings suggest that, for people who are undecided to adopt a new health action, LLC intervention might be more effective. PMID:22788244

  12. Unified force-level theory of multiscale transient localization and emergent elasticity in polymer solutions and melts

    NASA Astrophysics Data System (ADS)

    Dell, Zachary E.; Schweizer, Kenneth S.

    A unified, microscopic, theoretical understanding of polymer dynamics in concentrated liquids from segmental to macromolecular scales remains an open problem. We have formulated a statistical mechanical theory for this problem that explicitly accounts for intra- and inter-molecular forces at the Kuhn segment level. The theory is self-consistently closed at the level of a matrix of dynamical second moments of a tagged chain. Two distinct regimes of isotropic transient localization are predicted. In semidilute solutions, weak localization is predicted on a mesoscopic length scale between segment and chain scales which is a power law function of the invariant packing length. This is consistent with the breakdown of Rouse dynamics and the emergence of entanglements. The chain structural correlations in the dynamically arrested state are also computed. In dense melts, strong localization is predicted on a scale much smaller than the segment size which is weakly dependent on chain connectivity and signals the onset of glassy dynamics. Predictions of the dynamic plateau shear modulus are consistent with the known features of emergent rubbery and glassy elasticity. Generalizations to treat the effects of chemical crosslinking and physical bond formation in polymer gels are possible.

  13. Adaptive Calibration of Children's Physiological Responses to Family Stress: The Utility of Evolutionary Developmental Theory--Comment on Del Giudice et al. (2012) and Sturge-Apple et al. (2012)

    ERIC Educational Resources Information Center

    Bugental, Daphne Blunt

    2012-01-01

    Children's physiological reactions to stress are presented from the broader theoretical perspective of adaptive calibration to the environment, as rooted in life history theory. Del Giudice, Hinnant, Ellis, and El-Sheikh (2012) focus on children's physiological responses to a stressful task as a consequence of their history of family stress.…

  14. Application of refractive scintillation theory to laser transmission through the atmosphere near ground level

    NASA Astrophysics Data System (ADS)

    Booker, H. G.; Vats, H. O.

    1985-08-01

    On the basis of the work of Booker et al. (1985) and of Booker and MajidiAhi (1981), laser scintillation near ground level is discussed for divergent terminals at equal heights above a curved earth in an atmosphere possessing rms fluctuations of temperature from 0.03 C to 3 C. Except for short ranges and small temperature fluctuations, refractive scattering by large-scale irregularities dominates diffractive scattering by small-scale irregularities. Sample calculations are made of the intensity scintillation spectrum that occurs in the receiving plane. Simple formulae are given for the key scintillation parameters, namely, the outer scale, the Fresnel scale the mean square fluctuation of phase, the intensity correlation scale, the twinkling scale, the rms fluctuation in the angles of arrival and departure, and the correlation bandwidth. The numerical consequences of these formulae are illustrated

  15. Simplified combustion noise theory yielding a prediction of fluctuating pressure level

    NASA Technical Reports Server (NTRS)

    Huff, R. G.

    1984-01-01

    The first order equations for the conservation of mass and momentum in differential form are combined for an ideal gas to yield a single second order partial differential equation in one dimension and time. Small perturbation analysis is applied. A Fourier transformation is performed that results in a second order, constant coefficient, nonhomogeneous equation. The driving function is taken to be the source of combustion noise. A simplified model describing the energy addition via the combustion process gives the required source information for substitution in the driving function. This enables the particular integral solution of the nonhomogeneous equation to be found. This solution multiplied by the acoustic pressure efficiency predicts the acoustic pressure spectrum measured in turbine engine combustors. The prediction was compared with the overall sound pressure levels measured in a CF6-50 turbofan engine combustor and found to be in excellent agreement.

  16. Recruitment dynamics in adaptive social networks.

    PubMed

    Shkarayev, Maxim S; Schwartz, Ira B; Shaw, Leah B

    2013-01-01

    We model recruitment in adaptive social networks in the presence of birth and death processes. Recruitment is characterized by nodes changing their status to that of the recruiting class as a result of contact with recruiting nodes. Only a susceptible subset of nodes can be recruited. The recruiting individuals may adapt their connections in order to improve recruitment capabilities, thus changing the network structure adaptively. We derive a mean field theory to predict the dependence of the growth threshold of the recruiting class on the adaptation parameter. Furthermore, we investigate the effect of adaptation on the recruitment level, as well as on network topology. The theoretical predictions are compared with direct simulations of the full system. We identify two parameter regimes with qualitatively different bifurcation diagrams depending on whether nodes become susceptible frequently (multiple times in their lifetime) or rarely (much less than once per lifetime). PMID:25395989

  17. Age- and direction-related adaptations of lumbar vertebral trabecular bone with respect to apparent stiffness and tissue level stress distribution

    NASA Astrophysics Data System (ADS)

    Gong, He; Fan, Yubo; Zhang, Ming; Qin, Ling

    2009-02-01

    The objective of this study was to study the age-related adaptation of lumbar vertebral trabecular bone at the apparent level, as well as the tissue level in three orthogonal directions. Ninety trabecular specimens were obtained from six normal L4 vertebral bodies of six male cadavers in two age groups, three aged 62 years and three aged 69 years, and were scanned using a high-resolution micro-computed tomography (micro-CT) system, then converted to micro-finite element models to do micro-finite element analyses. The relationship between apparent stiffness and bone volume fraction, and the tissue level von Mises stress distribution for each trabecular specimen when compressed separately in the longitudinal direction, medial-lateral and anterior-posterior directions (transverse directions) were derived and compared between two age groups. The results showed that at the apparent level, trabecular bones from 69-year group had stiffer bone structure relative to their volume fractions in all three directions, and in both age groups, changes in bone volume fraction could explain more variations in apparent stiffness in the longitudinal direction than the transverse directions; at the tissue level, aging had little effect on the tissue von Mises stress distributions for the compressions in all the three directions. The novelty of the present study was that it provided quantitative assessments on the age and direction-related adaptation of Chinese male lumbar vertebral trabecular bone from two different levels: stiffness at the apparent level and stress distribution at the tissue level. It may help to understand the failure mechanisms and fracture risks of vertebral body associated with aging and direction for the prevention of fracture risks in elder individuals.

  18. Adaptive response of Rhodococcus opacus PWD4 to salt and phenolic stress on the level of mycolic acids.

    PubMed

    de Carvalho, Carla C C R; Fischer, Martin A; Kirsten, Sandra; Würz, Birgit; Wick, Lukas Y; Heipieper, Hermann J

    2016-12-01

    Mycolata form a group of Gram-positive bacteria with unique cell envelope structures that are known for their high tolerance against antibiotics and both aromatic and aliphatic hydrocarbons. An important part of the unique surface structure of the mycolata is the presence of long chain α-alkyl-β-hydroxy fatty acids, the mycolic acids. In order to investigate the adaptive changes in the mycolic acid composition, we investigated the composition of mycolic acids during the response both to osmotic stress caused by NaCl and to 4-chlorophenol in Rhodococcus opacus PWD4. This bacterium was chosen as it is known to adapt to different kinds of stresses. In addition, it is a potential biocatalyst in bioremediation as well as for biotechnological applications. In the present study, cells of R. opacus PWD4, grown in liquid cultures, responded to toxic concentrations of NaCl by increasing the ratio between mycolic acids and membrane phospholipid fatty acids (MA/PLFA-ratio). Cells reacted to both NaCl and 4-chlorophenol by decreasing both the average chain length and the unsaturation index of their mycolic acids. These changes in mycolic acid composition correlated with increases in cell surface hydrophobicity and saturation of membrane fatty acids, demonstrating the relation between mycolic acid and phospholipid synthesis and their contribution to cell surface properties of R. opacus PWD4. PMID:27620730

  19. Adaptation, aging, and genomic information

    PubMed Central

    Rose, Michael R.

    2009-01-01

    Aging is not simply an accumulation of damage or inappropriate higher-order signaling, though it does secondarily involve both of these subsidiary mechanisms. Rather, aging occurs because of the extensive absence of adaptive genomic information required for survival to, and function at, later adult ages, due to the declining forces of natural selection during adult life. This absence of information then secondarily leads to misallocations and damage at every level of biological organization. But the primary problem is a failure of adaptation at later ages. Contemporary proposals concerning means by which human aging can be ended or cured which are based on simple signaling or damage theories will thus reliably fail. Strategies based on reverse-engineering age-extended adaptation using experimental evolution and genomics offer the prospect of systematically greater success. PMID:20157529

  20. Elevated levels of adaption in Helicobacter pylori genomes from Japan; a link to higher incidences of gastric cancer?

    PubMed Central

    Soto-Girón, Maria Juliana; Ospina, Oscar E.; Massey, Steven Edward

    2015-01-01

    Helicobacter pylori is a bacterium that lives in the human stomach and is a major risk factor for gastric cancer and ulcers. H.pylori is host dependent and has been carried with human populations around the world after their departure from Africa. We wished to investigate how H.pylori has coevolved with its host during that time, focusing on strains from Japanese and European populations, given that gastric cancer incidence is high in Japanese populations, while low in European. A positive selection analysis of eight H.pylori genomes was conducted, using maximum likelihood based pairwise comparisons in order to maximize the number of strain-specific genes included in the study. Using the genic Ka/Ks ratio, comparisons of four Japanese H.pylori genomes suggests 25–34 genes under positive selection, while four European H.pylori genomes suggests 16–21 genes; few of the genes identified were in common between lineages. Of the identified genes which were annotated, 38% possessed homologs associated with pathogenicity and / or host adaptation, consistent with their involvement in a coevolutionary ‘arms race’ with the host. Given the efficacy of identifying host interaction factors de novo, in the absence of functionally annotated homologs our evolutionary approach may have value in identifying novel genes which H.pylori employs to interact with the human gut environment. In addition, the larger number of genes inferred as being under positive selection in Japanese strains compared to European implies a stronger overall adaptive pressure, potentially resulting from an elevated immune response which may be linked to increased inflammation, an initial stage in the development of gastric cancer. PMID:25788149

  1. Elevated levels of adaption in Helicobacter pylori genomes from Japan; a link to higher incidences of gastric cancer?

    PubMed

    Soto-Girón, Maria Juliana; Ospina, Oscar E; Massey, Steven Edward

    2015-01-01

    Helicobacter pylori is a bacterium that lives in the human stomach and is a major risk factor for gastric cancer and ulcers. H.pylori is host dependent and has been carried with human populations around the world after their departure from Africa. We wished to investigate how H.pylori has coevolved with its host during that time, focusing on strains from Japanese and European populations, given that gastric cancer incidence is high in Japanese populations, while low in European. A positive selection analysis of eight H.pylori genomes was conducted, using maximum likelihood based pairwise comparisons in order to maximize the number of strain-specific genes included in the study. Using the genic Ka/Ks ratio, comparisons of four Japanese H.pylori genomes suggests 25-34 genes under positive selection, while four European H.pylori genomes suggests 16-21 genes; few of the genes identified were in common between lineages. Of the identified genes which were annotated, 38% possessed homologs associated with pathogenicity and / or host adaptation, consistent with their involvement in a coevolutionary 'arms race' with the host. Given the efficacy of identifying host interaction factors de novo, in the absence of functionally annotated homologs our evolutionary approach may have value in identifying novel genes which H.pylori employs to interact with the human gut environment. In addition, the larger number of genes inferred as being under positive selection in Japanese strains compared to European implies a stronger overall adaptive pressure, potentially resulting from an elevated immune response which may be linked to increased inflammation, an initial stage in the development of gastric cancer. PMID:25788149

  2. Comparison of the Effective Fragment Potential Method with Symmetry-Adapted Perturbation Theory in the Calculation of Intermolecular Energies for Ionic Liquids.

    PubMed

    Tan, Samuel Y S; Izgorodina, Ekaterina I

    2016-06-14

    The effective fragment potential (EFP) method that decomposes the interaction energy as a sum of the five fundamental forces-electrostatic, exchange-repulsion, polarization, dispersion, and charge transfer-was applied to a large test set of ionic liquid ion pairs and compared against the state-of-the-art method, Symmetry-Adapted Perturbation Theory (SAPT). The ion pairs include imidazolium and pyrrolidinium cations combined with anions that are routinely used in the field of ionic liquids. The aug-cc-pVDZ, aug-cc-pVTZ, and 6-311++G(d,p) basis sets were used for EFP, while SAPT2+3/aug-cc-pVDZ provided the benchmark energies. Differences between the two methods were found to be large, and strongly dependent on the anion type. For the aug-cc-pVTZ basis set, which produced the least errors, average relative errors were between 2.3% and 18.4% for pyrrolidinium ion pairs and between 2.1% and 27.7% for imidazolium ion pairs for each individual energetic component (excluding charge transfer), as well as the total interaction energy. Charge transfer gave the largest relative errors: 56% and 63% on average for pyrrolidinium- and imidazolium-based ion pairs, respectively. Scaling of the EFP components against SAPT2+3 showed improvement for polarization (induction) and dispersion terms, thus indicating potential for the development of cost-effective alternatives for intermolecular induction and dispersion potentials for ionic liquids. PMID:27116302

  3. Development and applications of a unitary group adapted state specific multi-reference coupled cluster theory with internally contracted treatment of inactive double excitations

    NASA Astrophysics Data System (ADS)

    Sinha, Debalina; Maitra, Rahul; Mukherjee, Debashis

    2012-09-01

    Any multi-reference coupled cluster (MRCC) development based on the Jeziorski-Monkhorst (JM) multi-exponential ansatz for the wave-operator Ω suffers from spin-contamination problem for non-singlet states. We have very recently proposed a spin-free unitary group adapted (UGA) analogue of the JM ansatz, where the cluster operators are defined in terms of spin-free unitary generators and a normal ordered, rather than ordinary, exponential parametrization of Ω is used. A consequence of the latter choice is the emergence of the "direct term" of the MRCC equations that terminates at exactly the quartic power of the cluster amplitudes. Our UGA-MRCC ansatz has been utilized to generate both the spin-free state specific (SS) and the state universal MRCC formalisms. It is well-known that the SSMRCC theory requires suitable sufficiency conditions to resolve the redundancy of the cluster amplitudes. In this paper, we propose an alternative variant of the UGA-SSMRCC theory, where the sufficiency conditions are used for all cluster operators containing active orbitals and the single excitations with inactive orbitals, while the inactive double excitations are assumed to be independent of the model functions they act upon. The working equations for the inactive double excitations are thus derived in an internally contracted (IC) manner in the sense that the matrix elements entering the MRCC equations involve excitations from an entire combination of the model functions. We call this theory as UGA-ICID-MRCC, where ICID is the acronym for "Internally Contracted treatment of Inactive Double excitations." Since the number of such excitations are the most numerous, choosing them to be independent of the model functions will lead to very significant reduction in the number of cluster amplitudes for large active spaces, and is worth exploring. Moreover, unlike for the excitations involving active orbitals, where there is inadequate coupling between the model and the virtual functions

  4. Examining the ground and first excited states of methyl peroxy radical with high-level coupled-cluster theory

    NASA Astrophysics Data System (ADS)

    Copan, Andreas V.; Schaefer, Henry F., III; Agarwal, Jay

    2015-10-01

    Peroxy radicals (RO2) are intermediates in fuel combustion, where they engage in efficiency-limiting autoignition reactions. They also participate in atmospheric chemistry leading to the formation of unwanted tropospheric ozone. Advances in spectroscopic techniques have allowed for the possibility of employing the lowest (?) electronic transition of RO2 as a tool to selectively monitor these species, enabling accurate kinetic values to be obtained. Herein, high-level ab initio methods are employed to systematically refine spectroscopic predictions for the methyl peroxy radical (CH3O2), one of the most abundant peroxy radicals in the atmosphere. In particular, vibrationally corrected geometries and anharmonic vibrational frequencies for both the ground (?) and first excited (?) state are predicted using coupled-cluster theory with up to perturbative triples [CCSD(T)] and large atomic natural orbital basis sets. Equation-of-motion coupled-cluster theory is utilised to compute vertical ? transition properties; a radiative lifetime of 4.7 ms is suggested for the excited state. Finally, we predict the adiabatic excitation energy (T0) via systematic extrapolation to the complete basis limit of coupled-cluster with up to full quadruples (CCSDTQ). After accounting for several approximations, and including an anharmonic zero-point vibrational energy correction, we match experiment for this transition to within 9 cm-1. Dedicated to Professor Sourav Pal.

  5. Drought limitations to leaf-level gas exchange: results from a model linking stomatal optimization and cohesion-tension theory.

    PubMed

    Novick, Kimberly A; Miniat, Chelcy F; Vose, James M

    2016-03-01

    We merge concepts from stomatal optimization theory and cohesion-tension theory to examine the dynamics of three mechanisms that are potentially limiting to leaf-level gas exchange in trees during drought: (1) a 'demand limitation' driven by an assumption of optimal stomatal functioning; (2) 'hydraulic limitation' of water movement from the roots to the leaves; and (3) 'non-stomatal' limitations imposed by declining leaf water status within the leaf. Model results suggest that species-specific 'economics' of stomatal behaviour may play an important role in differentiating species along the continuum of isohydric to anisohydric behaviour; specifically, we show that non-stomatal and demand limitations may reduce stomatal conductance and increase leaf water potential, promoting wide safety margins characteristic of isohydric species. We used model results to develop a diagnostic framework to identify the most likely limiting mechanism to stomatal functioning during drought and showed that many of those features were commonly observed in field observations of tree water use dynamics. Direct comparisons of modelled and measured stomatal conductance further indicated that non-stomatal and demand limitations reproduced observed patterns of tree water use well for an isohydric species but that a hydraulic limitation likely applies in the case of an anisohydric species. PMID:26466749

  6. An adaptive spectral/DG method for a reduced phase-space based level set approach to geometrical optics on curved elements

    NASA Astrophysics Data System (ADS)

    Cockburn, Bernardo; Kao, Chiu-Yen; Reitich, Fernando

    2014-02-01

    We present an adaptive spectral/discontinuous Galerkin (DG) method on curved elements to simulate high-frequency wavefronts within a reduced phase-space formulation of geometrical optics. Following recent work, the approach is based on the use of level sets defined by functions satisfying the Liouville equations in reduced phase-space and, in particular, it relies on the smoothness of these functions to represent them by rapidly convergent spectral expansions in the phase variables. The resulting (hyperbolic) system of equations for the coefficients in these expansions are then amenable to a high-order accurate treatment via DG approximations. In the present work, we significantly expand on the applicability and efficiency of the approach by incorporating mechanisms that allow for its use in scattering simulations and for a reduced overall computational cost. With regards to the former we demonstrate that the incorporation of curved elements is necessary to attain any kind of accuracy in calculations that involve scattering off non-flat interfaces. With regards to efficiency, on the other hand, we also show that the level-set formulation allows for a space p-adaptive scheme that under-resolves the level-set functions away from the wavefront without incurring in a loss of accuracy in the approximation of its location. As we show, these improvements enable simulations that are beyond the capabilities of previous implementations of these numerical procedures.

  7. EPAC1 promotes adaptive responses in human arterial endothelial cells subjected to low levels of laminar fluid shear stress: Implications in flow-related endothelial dysfunction.

    PubMed

    Rampersad, Sarah N; Freitag, Silja I; Hubert, Fabien; Brzezinska, Paulina; Butler, Nathalie; Umana, M Bibiana; Wudwud, Alie R; Maurice, Donald H

    2016-06-01

    Blood flow-associated fluid shear stress (FSS) dynamically regulates the endothelium's ability to control arterial structure and function. While arterial endothelial cells (AEC) subjected to high levels of laminar FSS express a phenotype resistant to vascular insults, those exposed to low levels of laminar FSS, or to the FSS associated with oscillatory blood flow, are less resilient. Despite numerous reports highlighting how the cAMP-signaling system controls proliferation, migration and permeability of human AECs (HAECs), its role in coordinating HAEC responses to FSS has received scant attention. Herein we show that the cAMP effector EPAC1 is required for HAECs to align and elongate in the direction of flow, and for the induction of several anti-atherogenic and anti-thrombotic genes associated with these events. Of potential therapeutic importance, EPAC1 is shown to play a dominant role the in response of HAECs to low levels of laminar FSS, such as would be found within atherosclerosis-prone areas of the vasculature. Moreover, we show that EPAC1 promotes these HAEC responses to flow by regulating Vascular Endothelial Growth Factor Receptor-2 and Akt activation, within a VE-cadherin (VECAD)/PECAM1-based mechanosensor. We submit that these findings are consistent with the novel proposition that promoting EPAC1-signaling represents a novel means through which to promote expression of an adaptive phenotype in HAECs exposed to non-adaptive FSS-encoded signals as a consequence of vascular disease. PMID:26979996

  8. [Research on Adaptive Balance Reaction for Gait Slippery Instability Events on Level Walk Based on Plantar Pressure and Gait Parameter Analysis].

    PubMed

    Li, Yang; Zhang, Junxia; Si, Ying

    2015-12-01

    Nowadays, for gait instability phenomenon, many researches have been carried out at home and abroad. However, the relationship between plantar pressure and gait parameters in the process of balance adjustment is still unclear. This study describes the human body adaptive balance reaction during slip events on slippery level walk by plantar pressure and gait analysis. Ten healthy male subjects walked on a level path wearing shoes with two contrastive contaminants (dry, oil). The study collected and analyzed the change rule of spatiotemporal parameters, plantar pressure parameters, vertical ground reaction force (VGRF), etc. The results showed that the human body adaptive balance reaction during slip events on slippery level walk mainly included lighter touch at the heel strikes, tighter grip at the toe offs, a lower velocity, a shorter stride length and longer support time. These changes are used to maintain or recover body balance. These results would be able to explore new ideas and provide reference value for slip injury prevention, walking rehabilitation training design, research and development of walking assistive equipments, etc. PMID:27079090

  9. Method For Model-Reference Adaptive Control

    NASA Technical Reports Server (NTRS)

    Seraji, Homayoun

    1990-01-01

    Relatively simple method of model-reference adaptive control (MRAC) developed from two prior classes of MRAC techniques: signal-synthesis method and parameter-adaption method. Incorporated into unified theory, which yields more general adaptation scheme.

  10. Improved optimization of perturbation theory: Applications to the oscillator energy levels and Bose-Einstein condensate critical temperature

    NASA Astrophysics Data System (ADS)

    Kneur, Jean-Loïc; Neveu, André; Pinto, Marcus B.

    2004-05-01

    Improving perturbation theory via a variational optimization has generally produced in higher orders an embarrassingly large set of solutions, most of them unphysical (complex). We introduce an extension of the optimized perturbation method which leads to a drastic reduction of the number of acceptable solutions. The properties of this method are studied and it is then applied to the calculation of relevant quantities in different ϕ4 models, such as the anharmonic oscillator energy levels and the critical Bose-Einstein condensation temperature shift Δ Tc recently investigated by various authors. Our present estimates of Δ Tc , incorporating the most recently available six and seven loop perturbative information, are in excellent agreement with all the available lattice numerical simulations. This represents a very substantial improvement over previous treatments.

  11. Adaptation of anaerobically grown Thauera aromatica, Geobacter sulfurreducens and Desulfococcus multivorans to organic solvents on the level of membrane fatty acid composition

    PubMed Central

    Duldhardt, Ilka; Gaebel, Julia; Chrzanowski, Lukasz; Nijenhuis, Ivonne; Härtig, Claus; Schauer, Frieder; Heipieper, Hermann J.

    2010-01-01

    Summary The effect of different solvents and pollutants on the cellular fatty acid composition of three bacterial strains: Thauera aromatica, Geobacter sulfurreducens and Desulfococcus multivorans, representatives of diverse predominant anaerobic metabolisms was investigated. As the prevailing adaptive mechanism in cells of T. aromatica and G. sulfurreducens whose cellular fatty acids patterns were dominated by palmitic acid (C16:0) and palmitoleic acid (C16:1cis), the cells reacted by an increase in the degree of saturation of their membrane fatty acids when grown in the presence of sublethal concentrations of the chemicals. Next to palmitic acid C16:0, the fatty acid pattern of D. multivorans was dominated by anteiso‐branched fatty acids which are characteristic for several sulfate‐reducing bacteria. The cells responded to the solvents with an increase in the ratio of straight‐chain saturated (C14:0, C16:0, C18:0) to anteiso‐branched fatty acids (C15:0anteiso, C17:0anteiso, C17:1anteisoΔ9cis). The results show that anaerobic bacteria react with similar mechanisms like aerobic bacteria in order to adapt their membrane to toxic organic solvents. The observed adaptive modifications on the level of membrane fatty acid composition can only be carried out with de novo synthesis of the fatty acids which is strictly related to cell growth. As the growth rates of anaerobic bacteria are generally much lower than in the so far investigated aerobic bacteria, this adaptive response needs more time in anaerobic bacteria. This might be one explanation for the previously observed higher sensitivity of anaerobic bacteria when compared with aerobic ones. PMID:21255320

  12. Adaptation of anaerobically grown Thauera aromatica, Geobacter sulfurreducens and Desulfococcus multivorans to organic solvents on the level of membrane fatty acid composition.

    PubMed

    Duldhardt, Ilka; Gaebel, Julia; Chrzanowski, Lukasz; Nijenhuis, Ivonne; Härtig, Claus; Schauer, Frieder; Heipieper, Hermann J

    2010-03-01

    The effect of different solvents and pollutants on the cellular fatty acid composition of three bacterial strains: Thauera aromatica, Geobacter sulfurreducens and Desulfococcus multivorans, representatives of diverse predominant anaerobic metabolisms was investigated. As the prevailing adaptive mechanism in cells of T. aromatica and G. sulfurreducens whose cellular fatty acids patterns were dominated by palmitic acid (C16:0) and palmitoleic acid (C16:1cis), the cells reacted by an increase in the degree of saturation of their membrane fatty acids when grown in the presence of sublethal concentrations of the chemicals. Next to palmitic acid C16:0, the fatty acid pattern of D. multivorans was dominated by anteiso-branched fatty acids which are characteristic for several sulfate-reducing bacteria. The cells responded to the solvents with an increase in the ratio of straight-chain saturated (C14:0, C16:0, C18:0) to anteiso-branched fatty acids (C15:0anteiso, C17:0anteiso, C17:1anteisoΔ9cis). The results show that anaerobic bacteria react with similar mechanisms like aerobic bacteria in order to adapt their membrane to toxic organic solvents. The observed adaptive modifications on the level of membrane fatty acid composition can only be carried out with de novo synthesis of the fatty acids which is strictly related to cell growth. As the growth rates of anaerobic bacteria are generally much lower than in the so far investigated aerobic bacteria, this adaptive response needs more time in anaerobic bacteria. This might be one explanation for the previously observed higher sensitivity of anaerobic bacteria when compared with aerobic ones. PMID:21255320

  13. Direct detection of cellular adaptation to local cyclic stretching at the single cell level by atomic force microscopy.

    PubMed

    Watanabe-Nakayama, Takahiro; Machida, Shin-ichi; Harada, Ichiro; Sekiguchi, Hiroshi; Afrin, Rehana; Ikai, Atsushi

    2011-02-01

    The cellular response to external mechanical forces has important effects on numerous biological phenomena. The sequences of molecular events that underlie the observed changes in cellular properties have yet to be elucidated in detail. Here we have detected the responses of a cultured cell against locally applied cyclic stretching and compressive forces, after creating an artificial focal adhesion under a glass bead attached to the cantilever of an atomic force microscope. The cell tension initially increased in response to the tensile stress and then decreased within ∼1 min as a result of viscoelastic properties of the cell. This relaxation was followed by a gradual increase in tension extending over several minutes. The slow recovery of tension ceased after several cycles of force application. This tension-recovering activity was inhibited when cells were treated with cytochalasin D, an inhibitor of actin polymerization, or with (-)-blebbistatin, an inhibitor of myosin II ATPase activity, suggesting that the activity was driven by actin-myosin interaction. To our knowledge, this is the first quantitative analysis of cellular mechanical properties during the process of adaptation to locally applied cyclic external force. PMID:21281570

  14. Score level fusion scheme based on adaptive local Gabor features for face-iris-fingerprint multimodal biometric

    NASA Astrophysics Data System (ADS)

    He, Fei; Liu, Yuanning; Zhu, Xiaodong; Huang, Chun; Han, Ye; Chen, Ying

    2014-05-01

    A multimodal biometric system has been considered a promising technique to overcome the defects of unimodal biometric systems. We have introduced a fusion scheme to gain a better understanding and fusion method for a face-iris-fingerprint multimodal biometric system. In our case, we use particle swarm optimization to train a set of adaptive Gabor filters in order to achieve the proper Gabor basic functions for each modality. For a closer analysis of texture information, two different local Gabor features for each modality are produced by the corresponding Gabor coefficients. Next, all matching scores of the two Gabor features for each modality are projected to a single-scalar score via a trained, supported, vector regression model for a final decision. A large-scale dataset is formed to validate the proposed scheme using the Facial Recognition Technology database-fafb and CASIA-V3-Interval together with FVC2004-DB2a datasets. The experimental results demonstrate that as well as achieving further powerful local Gabor features of multimodalities and obtaining better recognition performance by their fusion strategy, our architecture also outperforms some state-of-the-art individual methods and other fusion approaches for face-iris-fingerprint multimodal biometric systems.

  15. A post-MI power struggle: adaptations in cardiac power occur at the sarcomere level alongside MyBP-C and RLC phosphorylation

    PubMed Central

    Sikkel, Markus B.; Caorsi, Valentina; Vydyanath, Anupama; Torre, Iratxe; Copeland, O'Neal; Lyon, Alexander R.; Marston, Steven B.; Luther, Pradeep K.; Macleod, Kenneth T.; West, Timothy G.; Ferenczi, Michael A.

    2016-01-01

    Myocardial remodeling in response to chronic myocardial infarction (CMI) progresses through two phases, hypertrophic “compensation” and congestive “decompensation.” Nothing is known about the ability of uninfarcted myocardium to produce force, velocity, and power during these clinical phases, even though adaptation in these regions likely drives progression of compensation. We hypothesized that enhanced cross-bridge-level contractility underlies mechanical compensation and is controlled in part by changes in the phosphorylation states of myosin regulatory proteins. We induced CMI in rats by left anterior descending coronary artery ligation. We then measured mechanical performance in permeabilized ventricular trabecula taken distant from the infarct zone and assayed myosin regulatory protein phosphorylation in each individual trabecula. During full activation, the compensated myocardium produced twice as much power and 31% greater isometric force compared with noninfarcted controls. Isometric force during submaximal activations was raised >2.4-fold, while power was 2-fold greater. Electron and confocal microscopy demonstrated that these mechanical changes were not a result of increased density of contractile protein and therefore not an effect of tissue hypertrophy. Hence, sarcomere-level contractile adaptations are key determinants of enhanced trabecular mechanics and of the overall cardiac compensatory response. Phosphorylation of myosin regulatory light chain (RLC) increased and remained elevated post-MI, while phosphorylation of myosin binding protein-C (MyBP-C) was initially depressed but then increased as the hearts became decompensated. These sensitivities to CMI are in accordance with phosphorylation-dependent regulatory roles for RLC and MyBP-C in crossbridge function and with compensatory adaptation in force and power that we observed in post-CMI trabeculae. PMID:27233767

  16. A post-MI power struggle: adaptations in cardiac power occur at the sarcomere level alongside MyBP-C and RLC phosphorylation.

    PubMed

    Toepfer, Christopher N; Sikkel, Markus B; Caorsi, Valentina; Vydyanath, Anupama; Torre, Iratxe; Copeland, O'Neal; Lyon, Alexander R; Marston, Steven B; Luther, Pradeep K; Macleod, Kenneth T; West, Timothy G; Ferenczi, Michael A

    2016-08-01

    Myocardial remodeling in response to chronic myocardial infarction (CMI) progresses through two phases, hypertrophic "compensation" and congestive "decompensation." Nothing is known about the ability of uninfarcted myocardium to produce force, velocity, and power during these clinical phases, even though adaptation in these regions likely drives progression of compensation. We hypothesized that enhanced cross-bridge-level contractility underlies mechanical compensation and is controlled in part by changes in the phosphorylation states of myosin regulatory proteins. We induced CMI in rats by left anterior descending coronary artery ligation. We then measured mechanical performance in permeabilized ventricular trabecula taken distant from the infarct zone and assayed myosin regulatory protein phosphorylation in each individual trabecula. During full activation, the compensated myocardium produced twice as much power and 31% greater isometric force compared with noninfarcted controls. Isometric force during submaximal activations was raised >2.4-fold, while power was 2-fold greater. Electron and confocal microscopy demonstrated that these mechanical changes were not a result of increased density of contractile protein and therefore not an effect of tissue hypertrophy. Hence, sarcomere-level contractile adaptations are key determinants of enhanced trabecular mechanics and of the overall cardiac compensatory response. Phosphorylation of myosin regulatory light chain (RLC) increased and remained elevated post-MI, while phosphorylation of myosin binding protein-C (MyBP-C) was initially depressed but then increased as the hearts became decompensated. These sensitivities to CMI are in accordance with phosphorylation-dependent regulatory roles for RLC and MyBP-C in crossbridge function and with compensatory adaptation in force and power that we observed in post-CMI trabeculae. PMID:27233767

  17. High water level impedes the adaptation of Polygonum hydropiper to deep burial: Responses of biomass allocation and root morphology

    PubMed Central

    Pan, Ying; Xie, Yong H.; Deng, Zheng M.; Tang, Yue; Pan, Dong D.

    2014-01-01

    Many studies have investigated the individual effects of sedimentation or inundation on the performance of wetland plants, but few have examined the combined influence of these processes. Wetland plants might show greater morphological plasticity in response to inundation than to sedimentation when these processes occur simultaneously since inundation can negate the negative effects of burial on plant growth. Here, we evaluate this hypothesis by assessing growth of the emergent macrophyte Polygonum hydropiper under flooding (0 and 40 cm) and sedimentation (0, 5, and 10 cm), separately and in combination. Deep burial and high water level each led to low oxidation-reduction potential, biomass (except for 5-cm burial), and growth of thick, short roots. These characteristics were generally more significant under high water level than under deep burial conditions. More biomass was allocated to stems in the deep burial treatments, but more to leaves in the high water level treatments. Additionally, biomass accumulation was lower and leaf mass ratio was higher in the 40-cm water level + 10-cm burial depth treatment than both separate effects. Our data indicate that inundation plays a more important role than sedimentation in determining plant morphology, suggesting hierarchical effects of environmental stressors on plant growth. PMID:25002329

  18. Agricultural fingerprints in salt-marsh sediments and adaptation to sea-level rise in the eastern Cantabrian coast (N. Spain)

    NASA Astrophysics Data System (ADS)

    García-Artola, Ane; Cearreta, Alejandro; Irabien, María Jesús; Leorri, Eduardo; Sanchez-Cabeza, Joan-Albert; Corbett, D. Reide

    2016-03-01

    A multi-proxy approach based on benthic foraminifera, sand content, short-lived radioisotope activities, heavy metal concentrations and aerial photography was developed to characterise the process of human disturbance on the intensely impacted eastern Cantabrian coast (N. Spain) over the last two centuries. Analysis of two 50 cm long sediment cores from different saltmarshes in the Santoña estuary and their comparison with previous results in nearby coastal areas defines criteria to identify records of agricultural activities in salt-marsh sediments. Agricultural occupation of saltmarshes and the later regeneration was recognised based on foraminifera and sand content. Saltmarshes in the eastern Cantabrian coast are expected to adapt to ongoing sea-level rise based on the high sedimentation rates (14-18 mm yr-1) observed during the regeneration process of previously reclaimed areas. These findings can potentially be useful in other temperate saltmarshes with abundant sediment input, as a cost-effective adaptation measure to counteract the effects of sea-level rise.

  19. Predicting students' intention to smoke by theory of planned behaviour variables and parental influences across school grade levels.

    PubMed

    Hassandra, Mary; Vlachopoulos, Symeon P; Kosmidou, Evdoxia; Hatzigeorgiadis, Antonis; Goudas, Marios; Theodorakis, Yiannis

    2011-09-01

    Differences were examined in Theory of Planned Behaviour determinants of students' intention to smoke including parents' attitudes towards smoking and parents' current cigarette use among Greek students of different school grade levels. Students (N = 763) aged 10-18 years reported their attitudes towards smoking, subjective norms, perceived behavioural control, self-identity and intention to smoke while their parents (N = 525) reported their attitudes towards smoking and their current cigarette use. All the TPB variables increased from lower to higher school grade level. Multi-sample path analyses showed that parent's attitudes towards smoking positively predicted students' intention to smoke only for elementary school children. Parents' current cigarette use did not contribute significantly. Students' attitudes, perceived behavioural control and self-identity predicted systematically intention to smoke in contrast to the subjective norm that did not contribute at all. Perceived behavioural control contributed to a higher degree in intention to smoke for senior high school students compared to the junior high school and elementary students. Self-identity contributed to a higher degree in intention to smoke for elementary compared to the junior high school students. The results of this study suggests that the determinants of smoking vary between early and late adolescence. PMID:21834644

  20. The Spread of Education and Fertility Decline: A Thai Province Level Test of Caldwell's "Wealth Flows" Theory.

    ERIC Educational Resources Information Center

    London, Bruce; Hadden, Kenneth

    1989-01-01

    Uses 1960-80 census data for 69 nonmetropolitan provinces of Thailand to assess theories of fertility decline. Finds that, congruent with Caldwell's theory, fertility reductions were greatest where mass education was most widespread, but aspects of political-economic and ecological theories were also supported. Contains 43 references. (SV)

  1. Alberta Diabetes and Physical Activity Trial (ADAPT): A randomized theory-based efficacy trial for adults with type 2 diabetes - rationale, design, recruitment, evaluation, and dissemination

    PubMed Central

    2010-01-01

    Background The primary aim of this study was to compare the efficacy of three physical activity (PA) behavioural intervention strategies in a sample of adults with type 2 diabetes. Method/Design Participants (N = 287) were randomly assigned to one of three groups consisting of the following intervention strategies: (1) standard printed PA educational materials provided by the Canadian Diabetes Association [i.e., Group 1/control group)]; (2) standard printed PA educational materials as in Group 1, pedometers, a log book and printed PA information matched to individuals' PA stage of readiness provided every 3 months (i.e., Group 2); and (3) PA telephone counseling protocol matched to PA stage of readiness and tailored to personal characteristics, in addition to the materials provided in Groups 1 and 2 (i.e., Group 3). PA behaviour measured by the Godin Leisure Time Exercise Questionnaire and related social-cognitive measures were assessed at baseline, 3, 6, 9, 12 and 18-months (i.e., 6-month follow-up). Clinical (biomarkers) and health-related quality of life assessments were conducted at baseline, 12-months, and 18-months. Linear Mixed Model (LMM) analyses will be used to examine time-dependent changes from baseline across study time points for Groups 2 and 3 relative to Group 1. Discussion ADAPT will determine whether tailored but low-cost interventions can lead to sustainable increases in PA behaviours. The results may have implications for practitioners in designing and implementing theory-based physical activity promotion programs for this population. Clinical Trials Registration ClinicalTrials.gov identifier: NCT00221234 PMID:20067626

  2. Van der Waals interactions between hydrocarbon molecules and zeolites: periodic calculations at different levels of theory, from density functional theory to the random phase approximation and Møller-Plesset perturbation theory.

    PubMed

    Göltl, Florian; Grüneis, Andreas; Bučko, Tomas; Hafner, Jürgen

    2012-09-21

    The adsorption of small alkane molecules in purely siliceous and protonated chabazite has been investigated at different levels of theory: (i) density-functional (DFT) calculations with a gradient-corrected exchange-correlation functional; DFT calculations using the Perdew-Burke-Ernzerhof (PBE) functional with corrections for the missing dispersion forces in the form of C(6)∕R(6) pair potentials with (ii) C(6) parameters and vdW radii determined by fitting accurate energies for a large molecular data base (PBE-d) or (iii) derived from "atoms in a solid" calculations; (iv) DFT calculations using a non-local correlation functional constructed such as to account for dispersion forces (vdW-DF); (v) calculations based on the random phase approximation (RPA) combined with the adiabatic-coupling fluctuation-dissipation theorem; and (vi) using Hartree-Fock (HF) calculations together with correlation energies calculated using second-order Møller-Plesset (MP2) perturbation theory. All calculations have been performed for periodic models of the zeolite and using a plane-wave basis and the projector-augmented wave method. The simpler and computationally less demanding approaches (i)-(iv) permit a calculation of the forces acting on the atoms using the Hellmann-Feynman theorem and further a structural optimization of the adsorbate-zeolite complex, while RPA and MP2 calculations can be performed only for a fixed geometry optimized at a lower level of theory. The influence of elevated temperature has been taken into account by averaging the adsorption energies calculated for purely siliceous and protonated chabazite, with weighting factors determined by molecular dynamics calculations with dispersion-corrected forces from DFT. Compared to experiment, the RPA underestimates the adsorption energies by about 5 kJ/mol while MP2 leads to an overestimation by about 6 kJ/Mol (averaged over methane, ethane, and propane). The most accurate results have been found for the "hybrid" RPA

  3. Van der Waals interactions between hydrocarbon molecules and zeolites: Periodic calculations at different levels of theory, from density functional theory to the random phase approximation and Møller-Plesset perturbation theory

    NASA Astrophysics Data System (ADS)

    Göltl, Florian; Grüneis, Andreas; Bučko, Tomas; Hafner, Jürgen

    2012-09-01

    The adsorption of small alkane molecules in purely siliceous and protonated chabazite has been investigated at different levels of theory: (i) density-functional (DFT) calculations with a gradient-corrected exchange-correlation functional; DFT calculations using the Perdew-Burke-Ernzerhof (PBE) functional with corrections for the missing dispersion forces in the form of C6/R6 pair potentials with (ii) C6 parameters and vdW radii determined by fitting accurate energies for a large molecular data base (PBE-d) or (iii) derived from "atoms in a solid" calculations; (iv) DFT calculations using a non-local correlation functional constructed such as to account for dispersion forces (vdW-DF); (v) calculations based on the random phase approximation (RPA) combined with the adiabatic-coupling fluctuation-dissipation theorem; and (vi) using Hartree-Fock (HF) calculations together with correlation energies calculated using second-order Møller-Plesset (MP2) perturbation theory. All calculations have been performed for periodic models of the zeolite and using a plane-wave basis and the projector-augmented wave method. The simpler and computationally less demanding approaches (i)-(iv) permit a calculation of the forces acting on the atoms using the Hellmann-Feynman theorem and further a structural optimization of the adsorbate-zeolite complex, while RPA and MP2 calculations can be performed only for a fixed geometry optimized at a lower level of theory. The influence of elevated temperature has been taken into account by averaging the adsorption energies calculated for purely siliceous and protonated chabazite, with weighting factors determined by molecular dynamics calculations with dispersion-corrected forces from DFT. Compared to experiment, the RPA underestimates the adsorption energies by about 5 kJ/mol while MP2 leads to an overestimation by about 6 kJ/Mol (averaged over methane, ethane, and propane). The most accurate results have been found for the "hybrid" RPA-HF method

  4. Adaptive antennas

    NASA Astrophysics Data System (ADS)

    Barton, P.

    1987-04-01

    The basic principles of adaptive antennas are outlined in terms of the Wiener-Hopf expression for maximizing signal to noise ratio in an arbitrary noise environment; the analogy with generalized matched filter theory provides a useful aid to understanding. For many applications, there is insufficient information to achieve the above solution and thus non-optimum constrained null steering algorithms are also described, together with a summary of methods for preventing wanted signals being nulled by the adaptive system. The three generic approaches to adaptive weight control are discussed; correlation steepest descent, weight perturbation and direct solutions based on sample matrix conversion. The tradeoffs between hardware complexity and performance in terms of null depth and convergence rate are outlined. The sidelobe cancellor technique is described. Performance variation with jammer power and angular distribution is summarized and the key performance limitations identified. The configuration and performance characteristics of both multiple beam and phase scan array antennas are covered, with a brief discussion of performance factors.

  5. ASSESSMENT OF CLINICAL IMAGE QUALITY IN PAEDIATRIC ABDOMINAL CT EXAMINATIONS: DEPENDENCY ON THE LEVEL OF ADAPTIVE STATISTICAL ITERATIVE RECONSTRUCTION (ASiR) AND THE TYPE OF CONVOLUTION KERNEL.

    PubMed

    Larsson, Joel; Båth, Magnus; Ledenius, Kerstin; Caisander, Håkan; Thilander-Klang, Anne

    2016-06-01

    The purpose of this study was to investigate the effect of different combinations of convolution kernel and the level of Adaptive Statistical iterative Reconstruction (ASiR™) on diagnostic image quality as well as visualisation of anatomical structures in paediatric abdominal computed tomography (CT) examinations. Thirty-five paediatric patients with abdominal pain with non-specified pathology undergoing abdominal CT were included in the study. Transaxial stacks of 5-mm-thick images were retrospectively reconstructed at various ASiR levels, in combination with three convolution kernels. Four paediatric radiologists rated the diagnostic image quality and the delineation of six anatomical structures in a blinded randomised visual grading study. Image quality at a given ASiR level was found to be dependent on the kernel, and a more edge-enhancing kernel benefitted from a higher ASiR level. An ASiR level of 70 % together with the Soft™ or Standard™ kernel was suggested to be the optimal combination for paediatric abdominal CT examinations. PMID:26922785

  6. A Self-Adaptive Dynamic Recognition Model for Fatigue Driving Based on Multi-Source Information and Two Levels of Fusion

    PubMed Central

    Sun, Wei; Zhang, Xiaorui; Peeta, Srinivas; He, Xiaozheng; Li, Yongfu; Zhu, Senlai

    2015-01-01

    To improve the effectiveness and robustness of fatigue driving recognition, a self-adaptive dynamic recognition model is proposed that incorporates information from multiple sources and involves two sequential levels of fusion, constructed at the feature level and the decision level. Compared with existing models, the proposed model introduces a dynamic basic probability assignment (BPA) to the decision-level fusion such that the weight of each feature source can change dynamically with the real-time fatigue feature measurements. Further, the proposed model can combine the fatigue state at the previous time step in the decision-level fusion to improve the robustness of the fatigue driving recognition. An improved correction strategy of the BPA is also proposed to accommodate the decision conflict caused by external disturbances. Results from field experiments demonstrate that the effectiveness and robustness of the proposed model are better than those of models based on a single fatigue feature and/or single-source information fusion, especially when the most effective fatigue features are used in the proposed model. PMID:26393615

  7. A Self-Adaptive Dynamic Recognition Model for Fatigue Driving Based on Multi-Source Information and Two Levels of Fusion.

    PubMed

    Sun, Wei; Zhang, Xiaorui; Peeta, Srinivas; He, Xiaozheng; Li, Yongfu; Zhu, Senlai

    2015-01-01

    To improve the effectiveness and robustness of fatigue driving recognition, a self-adaptive dynamic recognition model is proposed that incorporates information from multiple sources and involves two sequential levels of fusion, constructed at the feature level and the decision level. Compared with existing models, the proposed model introduces a dynamic basic probability assignment (BPA) to the decision-level fusion such that the weight of each feature source can change dynamically with the real-time fatigue feature measurements. Further, the proposed model can combine the fatigue state at the previous time step in the decision-level fusion to improve the robustness of the fatigue driving recognition. An improved correction strategy of the BPA is also proposed to accommodate the decision conflict caused by external disturbances. Results from field experiments demonstrate that the effectiveness and robustness of the proposed model are better than those of models based on a single fatigue feature and/or single-source information fusion, especially when the most effective fatigue features are used in the proposed model. PMID:26393615

  8. Epidemic Spreading on Preferred Degree Adaptive Networks

    PubMed Central

    Jolad, Shivakumar; Liu, Wenjia; Schmittmann, B.; Zia, R. K. P.

    2012-01-01

    We study the standard SIS model of epidemic spreading on networks where individuals have a fluctuating number of connections around a preferred degree . Using very simple rules for forming such preferred degree networks, we find some unusual statistical properties not found in familiar Erdös-Rényi or scale free networks. By letting depend on the fraction of infected individuals, we model the behavioral changes in response to how the extent of the epidemic is perceived. In our models, the behavioral adaptations can be either ‘blind’ or ‘selective’ – depending on whether a node adapts by cutting or adding links to randomly chosen partners or selectively, based on the state of the partner. For a frozen preferred network, we find that the infection threshold follows the heterogeneous mean field result and the phase diagram matches the predictions of the annealed adjacency matrix (AAM) approach. With ‘blind’ adaptations, although the epidemic threshold remains unchanged, the infection level is substantially affected, depending on the details of the adaptation. The ‘selective’ adaptive SIS models are most interesting. Both the threshold and the level of infection changes, controlled not only by how the adaptations are implemented but also how often the nodes cut/add links (compared to the time scales of the epidemic spreading). A simple mean field theory is presented for the selective adaptations which capture the qualitative and some of the quantitative features of the infection phase diagram. PMID:23189133

  9. Is "the perfect model" really needed? - Analysis of the quality level of climate information necessary for supporting adaptation in agriculture and forestry

    NASA Astrophysics Data System (ADS)

    Gálos, Borbála; Ostler, Wolf-Uwe; Csáki, Péter; Bidló, András; Panferov, Oleg

    2016-04-01

    Recent results of climate science (e.g. IPCC AR5, 2013) and statements of climate policy (e.g. Paris Agreement) confirm that climate change is an ongoing issue. The consequences will be noticeable for a long time even if the 2 Degree goal is reached. Therefore, action plans are necessary for adaptation and mitigation on national and international level. Forestry and agriculture are especially threatened by the probable increase of the frequency and/or intensity of climate extremes. Severe impacts of recurrent droughts/heat waves that were observed in the last decades in the sensitive and vulnerable ecosystems and regions are very likely to occur with increasing probability throughout the 21st century. For the adequate climate impact assessments, for adaptation strategies as well as for supporting decisions in the above mentioned sectors the reliable information on the long-term climate tendencies and on ecosystem responses are required. Here are the two major problems: on the one hand the information on current climate and future climate developments are highly uncertain. On the other hand, due to limited knowledge on ecosystem responses, it is difficult to define how certain or accurate the provided climate data should be for the plausible application in agricultural/forestry research and practice. Considering agriculture and forestry, our research is focusing on the following questions: • What is the climate information demand of practice and impact research in the two sectors? • What quality level of climate information is necessary for adaptation support? • How does the accuracy of climate input affect the results of the climate impact assessments? The agriculture and forestry operate at two very different time scales and have a different reaction times and adaptation capacities. Agriculture requires short-term information on current conditions and short-/medium-term weather forecast. To assess the degree of information accuracy required by practical

  10. A Socio-Ecological Approach for Identifying and Contextualising Spatial Ecosystem-Based Adaptation Priorities at the Sub-National Level

    PubMed Central

    Bourne, Amanda; Holness, Stephen; Holden, Petra; Scorgie, Sarshen; Donatti, Camila I.; Midgley, Guy

    2016-01-01

    Climate change adds an additional layer of complexity to existing sustainable development and biodiversity conservation challenges. The impacts of global climate change are felt locally, and thus local governance structures will increasingly be responsible for preparedness and local responses. Ecosystem-based adaptation (EbA) options are gaining prominence as relevant climate change solutions. Local government officials seldom have an appropriate understanding of the role of ecosystem functioning in sustainable development goals, or access to relevant climate information. Thus the use of ecosystems in helping people adapt to climate change is limited partially by the lack of information on where ecosystems have the highest potential to do so. To begin overcoming this barrier, Conservation South Africa in partnership with local government developed a socio-ecological approach for identifying spatial EbA priorities at the sub-national level. Using GIS-based multi-criteria analysis and vegetation distribution models, the authors have spatially integrated relevant ecological and social information at a scale appropriate to inform local level political, administrative, and operational decision makers. This is the first systematic approach of which we are aware that highlights spatial priority areas for EbA implementation. Nodes of socio-ecological vulnerability are identified, and the inclusion of areas that provide ecosystem services and ecological resilience to future climate change is innovative. The purpose of this paper is to present and demonstrate a methodology for combining complex information into user-friendly spatial products for local level decision making on EbA. The authors focus on illustrating the kinds of products that can be generated from combining information in the suggested ways, and do not discuss the nuance of climate models nor present specific technical details of the model outputs here. Two representative case studies from rural South Africa

  11. A Socio-Ecological Approach for Identifying and Contextualising Spatial Ecosystem-Based Adaptation Priorities at the Sub-National Level.

    PubMed

    Bourne, Amanda; Holness, Stephen; Holden, Petra; Scorgie, Sarshen; Donatti, Camila I; Midgley, Guy

    2016-01-01

    Climate change adds an additional layer of complexity to existing sustainable development and biodiversity conservation challenges. The impacts of global climate change are felt locally, and thus local governance structures will increasingly be responsible for preparedness and local responses. Ecosystem-based adaptation (EbA) options are gaining prominence as relevant climate change solutions. Local government officials seldom have an appropriate understanding of the role of ecosystem functioning in sustainable development goals, or access to relevant climate information. Thus the use of ecosystems in helping people adapt to climate change is limited partially by the lack of information on where ecosystems have the highest potential to do so. To begin overcoming this barrier, Conservation South Africa in partnership with local government developed a socio-ecological approach for identifying spatial EbA priorities at the sub-national level. Using GIS-based multi-criteria analysis and vegetation distribution models, the authors have spatially integrated relevant ecological and social information at a scale appropriate to inform local level political, administrative, and operational decision makers. This is the first systematic approach of which we are aware that highlights spatial priority areas for EbA implementation. Nodes of socio-ecological vulnerability are identified, and the inclusion of areas that provide ecosystem services and ecological resilience to future climate change is innovative. The purpose of this paper is to present and demonstrate a methodology for combining complex information into user-friendly spatial products for local level decision making on EbA. The authors focus on illustrating the kinds of products that can be generated from combining information in the suggested ways, and do not discuss the nuance of climate models nor present specific technical details of the model outputs here. Two representative case studies from rural South Africa

  12. Adaptive homeostasis.

    PubMed

    Davies, Kelvin J A

    2016-06-01

    Homeostasis is a central pillar of modern Physiology. The term homeostasis was invented by Walter Bradford Cannon in an attempt to extend and codify the principle of 'milieu intérieur,' or a constant interior bodily environment, that had previously been postulated by Claude Bernard. Clearly, 'milieu intérieur' and homeostasis have served us well for over a century. Nevertheless, research on signal transduction systems that regulate gene expression, or that cause biochemical alterations to existing enzymes, in response to external and internal stimuli, makes it clear that biological systems are continuously making short-term adaptations both to set-points, and to the range of 'normal' capacity. These transient adaptations typically occur in response to relatively mild changes in conditions, to programs of exercise training, or to sub-toxic, non-damaging levels of chemical agents; thus, the terms hormesis, heterostasis, and allostasis are not accurate descriptors. Therefore, an operational adjustment to our understanding of homeostasis suggests that the modified term, Adaptive Homeostasis, may be useful especially in studies of stress, toxicology, disease, and aging. Adaptive Homeostasis may be defined as follows: 'The transient expansion or contraction of the homeostatic range in response to exposure to sub-toxic, non-damaging, signaling molecules or events, or the removal or cessation of such molecules or events.' PMID:27112802

  13. Synthesizing within-host and population-level selective pressures on viral populations: the impact of adaptive immunity on viral immune escape

    PubMed Central

    Volkov, Igor; Pepin, Kim M.; Lloyd-Smith, James O.; Banavar, Jayanth R.; Grenfell, Bryan T.

    2010-01-01

    The evolution of viruses to escape prevailing host immunity involves selection at multiple integrative scales, from within-host viral and immune kinetics to the host population level. In order to understand how viral immune escape occurs, we develop an analytical framework that links the dynamical nature of immunity and viral variation across these scales. Our epidemiological model incorporates within-host viral evolutionary dynamics for a virus that causes acute infections (e.g. influenza and norovirus) with changes in host immunity in response to genetic changes in the virus population. We use a deterministic description of the within-host replication dynamics of the virus, the pool of susceptible host cells and the host adaptive immune response. We find that viral immune escape is most effective at intermediate values of immune strength. At very low levels of immunity, selection is too weak to drive immune escape in recovered hosts, while very high levels of immunity impose such strong selection that viral subpopulations go extinct before acquiring enough genetic diversity to escape host immunity. This result echoes the predictions of simpler models, but our formulation allows us to dissect the combination of within-host and transmission-level processes that drive immune escape. PMID:20335194

  14. High levels of glucose-6-phosphatase gene and protein expression reflect an adaptive response in proliferating liver and diabetes.

    PubMed Central

    Haber, B A; Chin, S; Chuang, E; Buikhuisen, W; Naji, A; Taub, R

    1995-01-01

    The regenerating liver after partial hepatectomy is one of the few physiologic models of cellular proliferation in the adult animal. During hepatic regeneration, the animal is able to maintain metabolic homeostasis despite the acute loss of two thirds of hepatic tissue. In examining the molecular mechanisms regulating hepatic regeneration, we isolated novel immediate-early genes that are rapidly induced as the remnant liver undergoes the transition from its normal quiescent state into the G1 phase of the cell cycle. One of the most rapidly and highly induced genes which we initially termed RL-1, encodes rat glucose-6-phosphatase (rG6Pase). G6Pase mRNA peaks at 30 min and 36-48 h after hepatectomy correlating with the first and second rounds of cell division. This finding is compatible with studies that showed that G6Pase enzyme activity increases during liver regeneration. However, the increase in G6Pase mRNA is much more dramatic, indicating that it is a more sensitive indicator of this regulation. G6Pase gene expression peaks in the perinatal time period in the liver and remains elevated during the first month of life. The expression of the G6Pase gene is also dramatically elevated in BB diabetic rats, again higher than the enzyme elevation, and its relative induction after partial hepatectomy is blunted in these animals. Insulin treatment of partially hepatectomized diabetic animals downregulates the expression of G6Pase mRNA. Using specific antibodies against G6Pase, we detect a 36-kD G6Pase protein, and its level is elevated in regenerating and diabetic livers. The pattern of G6Pase mRNA expression appears to reflect similar changes in insulin and glucagon levels which accompany diabetes and hepatic proliferation. The elevation of G6Pase expression in these conditions is indicative of its importance as a regulator of glucose homeostasis in normal and abnormal physiologic states. Images PMID:7860767

  15. Limits to adaptation along environmental gradients.

    PubMed

    Polechová, Jitka; Barton, Nicholas H

    2015-05-19

    Why do species not adapt to ever-wider ranges of conditions, gradually expanding their ecological niche and geographic range? Gene flow across environments has two conflicting effects: although it increases genetic variation, which is a prerequisite for adaptation, gene flow may swamp adaptation to local conditions. In 1956, Haldane proposed that, when the environment varies across space, "swamping" by gene flow creates a positive feedback between low population size and maladaptation, leading to a sharp range margin. However, current deterministic theory shows that, when variance can evolve, there is no such limit. Using simple analytical tools and simulations, we show that genetic drift can generate a sharp margin to a species' range, by reducing genetic variance below the level needed for adaptation to spatially variable conditions. Aided by separation of ecological and evolutionary timescales, the identified effective dimensionless parameters reveal a simple threshold that predicts when adaptation at the range margin fails. Two observable parameters determine the threshold: (i) the effective environmental gradient, which can be measured by the loss of fitness due to dispersal to a different environment; and (ii) the efficacy of selection relative to genetic drift. The theory predicts sharp range margins even in the absence of abrupt changes in the environment. Furthermore, it implies that gradual worsening of conditions across a species' habitat may lead to a sudden range fragmentation, when adaptation to a wide span of conditions within a single species becomes impossible. PMID:25941385

  16. ADAPTATION AND IMPLEMENTATION OF HoMBReS: A COMMUNITY-LEVEL, EVIDENCE-BASED HIV BEHAVIORAL INTERVENTION FOR HETEROSEXUAL LATINO MEN IN THE MIDWESTERN UNITED STATES

    PubMed Central

    Martinez, Omar; Roth, Alexis M.; Kelle, Guadalupe; Downs, Mario; Rhodes, Scott D.

    2014-01-01

    Over the past decade, the midwestern United States has witnessed a dramatic increase in its Latino population. The lack of culturally and linguistically congruent resources coupled with high incidence and prevalence rates of HIV among Latinos living in the Midwest merits attention. HoMBReS: Hombres Manteniendo Bienestar y Relaciones Saludables (Men Maintaining Wellbeing and Healthy Relationships) is a community-level social network intervention designed for Latino men. We describe the adaptation and implementation of HoMBReS for Latino men living in Indianapolis, Indiana, the second largest city in the Midwest. Five Navegantes (lay health educators) were trained; they provided a total of 34 educational charlas (small group didactic sessions). A total of 270 Latino men attended the charlas and were offered no-cost screening for HIV and sexually transmitted infections (STI). Three participants tested HIV positive and 15 screened positive for STI. The charlas coupled with the testing initiative, served as a successful method to increase sexual health knowledge among Latino men and to link newly-diagnosed HIV/STI-positive individuals to treatment and care. The adaptation and implementation of HoMBReS respond to the CDC and NIH call to increase HIV testing and service provision among vulnerable populations. PMID:24450279

  17. Decentralized adaptive control

    NASA Technical Reports Server (NTRS)

    Oh, B. J.; Jamshidi, M.; Seraji, H.

    1988-01-01

    A decentralized adaptive control is proposed to stabilize and track the nonlinear, interconnected subsystems with unknown parameters. The adaptation of the controller gain is derived by using model reference adaptive control theory based on Lyapunov's direct method. The adaptive gains consist of sigma, proportional, and integral combination of the measured and reference values of the corresponding subsystem. The proposed control is applied to the joint control of a two-link robot manipulator, and the performance in computer simulation corresponds with what is expected in theoretical development.

  18. Constructive Developmental Theory and Programming across Cultures: An Examination of the Development and Experiences of Adult Burmese Participants in a High Quality Adaptive Capacity Development Program

    ERIC Educational Resources Information Center

    Lindsley, Robert Bugden

    2011-01-01

    A recent movement in international development has seen the expansion of capacity development activities to include adaptive approaches to education. Adaptive approaches are distinct from traditional approaches to education as they seek not only to provide new knowledge, but to cultivate more complex and flexible qualities of mind. Borrowed from…

  19. Adaptation Research in Rehabilitation Counseling

    ERIC Educational Resources Information Center

    Parker, Randall M.

    2007-01-01

    This paper reviews current research concerning psychosocial adaptation to chronic illness and disability and presents recommendations for future development of theories in this area. First, those who craft or adapt theories must use nondisabling, respectful, and empowering language. Rehabilitation professionals must avoid terms that connote…

  20. The semi-implicit, adaptive Multi-Level Multi-Domain method for Particle In Cell plasma simulations

    NASA Astrophysics Data System (ADS)

    Innocenti, Maria Elena; Markidis, Stefano; Lapenta, Giovanni

    2015-11-01

    The Multi Level Multi Domain (MLMD) method (Innocenti (2013), Beck (2014)) is a fully kinetic, semi-implicit PIC method which simulates a domain as a collection of sub-domains where increasingly higher resolution is used. The aim is to reduce the computational costs of PIC simulations: simulations which are computationally challenging even with a traditional semi-implicit PIC code, e.g., realistic mass ratio simulations, become feasible with moderate computational resources. We present two sets of realistic mass ratio simulations: magnetic reconnection and Lower Hybrid Drift Instability (LHDI). MLMD reconnection simulations are discussed in Innocenti (2015). In the MLMD LHDI simulations, we show how the MLMD method cheaply extends the range of simulatedwavenumbers with respect to traditional simulations. We simulate the three LHDI stages (fast and slow LHDI branch, kink instability), which are well separated in wavenumber at realistic mass ratio. The coupling observed by Norgren (2012) between the magnetic field and perpendicular electric field LHDI oscillations in the magnetotail is investigated in these different stages. NERSC, Contract N. DE-AC02-05CH11231, PRACE SuperMUC, contract N. 2013091928, FWO, grant N. 12O5215N.

  1. A New Look at Adaptation.

    ERIC Educational Resources Information Center

    Buttolph, Diana

    1992-01-01

    Examines terms used to describe the changing of an innovation by an adopter, including reinvention, fidelity, adaptation, and mutual adaptation. Three explanations for adaptation of innovation--interpretation, adopter innovativeness, and generative learning--are discussed; and the theory of generative learning is used to explain internal…

  2. Modeled Sea Level Rise Impacts on Coastal Ecosystems at Six Major Estuaries on Florida’s Gulf Coast: Implications for Adaptation Planning

    PubMed Central

    Birch, Anne P.; Brenner, Jorge; Gordon, Doria R.

    2015-01-01

    The Sea Level Affecting Marshes Model (SLAMM) was applied at six major estuaries along Florida’s Gulf Coast (Pensacola Bay, St. Andrews/Choctawhatchee Bays, Apalachicola Bay, Southern Big Bend, Tampa Bay and Charlotte Harbor) to provide quantitative and spatial information on how coastal ecosystems may change with sea level rise (SLR) and to identify how this information can be used to inform adaption planning. High resolution LiDAR-derived elevation data was utilized under three SLR scenarios: 0.7 m, 1 m and 2 m through the year 2100 and uncertainty analyses were conducted on selected input parameters at three sites. Results indicate that the extent, spatial orientation and relative composition of coastal ecosystems at the study areas may substantially change with SLR. Under the 1 m SLR scenario, total predicted impacts for all study areas indicate that coastal forest (-69,308 ha; -18%), undeveloped dry land (-28,444 ha; -2%) and tidal flat (-25,556 ha; -47%) will likely face the greatest loss in cover by the year 2100. The largest potential gains in cover were predicted for saltmarsh (+32,922 ha; +88%), transitional saltmarsh (+23,645 ha; na) and mangrove forest (+12,583 ha; +40%). The Charlotte Harbor and Tampa Bay study areas were predicted to experience the greatest net loss in coastal wetlands The uncertainty analyses revealed low to moderate changes in results when some numerical SLAMM input parameters were varied highlighting the value of collecting long-term sedimentation, accretion and erosion data to improve SLAMM precision. The changes predicted by SLAMM will affect exposure of adjacent human communities to coastal hazards and ecosystem functions potentially resulting in impacts to property values, infrastructure investment and insurance rates. The results and process presented here can be used as a guide for communities vulnerable to SLR to identify and prioritize adaptation strategies that slow and/or accommodate the changes underway. PMID:26207914

  3. Quantifying the Adaptive Cycle

    PubMed Central

    Angeler, David G.; Allen, Craig R.; Garmestani, Ahjond S.; Gunderson, Lance H.; Hjerne, Olle; Winder, Monika

    2015-01-01

    The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation) in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994–2011) data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and adaptation provides opportunities to cope with the intricacies and uncertainties associated with fast ecological change, driven by shifting system controls. Ultimately, combining traditional ecological paradigms with heuristics of complex system dynamics using quantitative approaches may help refine ecological theory and improve our understanding of the resilience of ecosystems. PMID:26716453

  4. Different Levels of the Meaning of Wave-Particle Duality and a Suspensive Perspective on the Interpretation of Quantum Theory

    ERIC Educational Resources Information Center

    Cheong, Yong Wook; Song, Jinwoong

    2014-01-01

    There is no consensus on the genuine meaning of wave-particle duality and the interpretation of quantum theory. How can we teach duality and quantum theory despite this lack of consensus? This study attempts to answer this question. This research argues that reality issues are at the core of both the endless debates concerning the interpretation…

  5. Origins of adaptive immunity.

    PubMed

    Liongue, Clifford; John, Liza B; Ward, Alister

    2011-01-01

    Adaptive immunity, involving distinctive antibody- and cell-mediated responses to specific antigens based on "memory" of previous exposure, is a hallmark of higher vertebrates. It has been argued that adaptive immunity arose rapidly, as articulated in the "big bang theory" surrounding its origins, which stresses the importance of coincident whole-genome duplications. Through a close examination of the key molecules and molecular processes underpinning adaptive immunity, this review suggests a less-extreme model, in which adaptive immunity emerged as part of longer evolutionary journey. Clearly, whole-genome duplications provided additional raw genetic materials that were vital to the emergence of adaptive immunity, but a variety of other genetic events were also required to generate some of the key molecules, whereas others were preexisting and simply co-opted into adaptive immunity. PMID:21395512

  6. Altered Brain Network in Amyotrophic Lateral Sclerosis: A Resting Graph Theory-Based Network Study at Voxel-Wise Level.

    PubMed

    Zhou, Chaoyang; Hu, Xiaofei; Hu, Jun; Liang, Minglong; Yin, Xuntao; Chen, Lin; Zhang, Jiuquan; Wang, Jian

    2016-01-01

    Amyotrophic lateral sclerosis (ALS) is a rare degenerative disorder characterized by loss of upper and lower motor neurons. Neuroimaging has provided noticeable evidence that ALS is a complex disease, and shown that anatomical and functional lesions extend beyond precentral cortices and corticospinal tracts, to include the corpus callosum; frontal, sensory, and premotor cortices; thalamus; and midbrain. The aim of this study is to investigate graph theory-based functional network abnormalities at voxel-wise level in ALS patients on a whole brain scale. Forty-three ALS patients and 44 age- and sex-matched healthy volunteers were enrolled. The voxel-wise network degree centrality (DC), a commonly employed graph-based measure of network organization, was used to characterize the alteration of whole brain functional network. Compared with the controls, the ALS patients showed significant increase of DC in the left cerebellum posterior lobes, bilateral cerebellum crus, bilateral occipital poles, right orbital frontal lobe, and bilateral prefrontal lobes; significant decrease of DC in the bilateral primary motor cortex, bilateral sensory motor region, right prefrontal lobe, left bilateral precuneus, bilateral lateral temporal lobes, left cingulate cortex, and bilateral visual processing cortex. The DC's z-scores of right inferior occipital gyrus were significant negative correlated with the ALSFRS-r scores. Our findings confirm that the regions with abnormal network DC in ALS patients were located in multiple brain regions including primary motor, somatosensory and extra-motor areas, supporting the concept that ALS is a multisystem disorder. Specifically, our study found that DC in the visual areas was altered and ALS patients with higher DC in right inferior occipital gyrus have more severity of disease. The result demonstrated that the altered DC value in this region can probably be used to assess severity of ALS. PMID:27242409

  7. Altered Brain Network in Amyotrophic Lateral Sclerosis: A Resting Graph Theory-Based Network Study at Voxel-Wise Level

    PubMed Central

    Zhou, Chaoyang; Hu, Xiaofei; Hu, Jun; Liang, Minglong; Yin, Xuntao; Chen, Lin; Zhang, Jiuquan; Wang, Jian

    2016-01-01

    Amyotrophic lateral sclerosis (ALS) is a rare degenerative disorder characterized by loss of upper and lower motor neurons. Neuroimaging has provided noticeable evidence that ALS is a complex disease, and shown that anatomical and functional lesions extend beyond precentral cortices and corticospinal tracts, to include the corpus callosum; frontal, sensory, and premotor cortices; thalamus; and midbrain. The aim of this study is to investigate graph theory-based functional network abnormalities at voxel-wise level in ALS patients on a whole brain scale. Forty-three ALS patients and 44 age- and sex-matched healthy volunteers were enrolled. The voxel-wise network degree centrality (DC), a commonly employed graph-based measure of network organization, was used to characterize the alteration of whole brain functional network. Compared with the controls, the ALS patients showed significant increase of DC in the left cerebellum posterior lobes, bilateral cerebellum crus, bilateral occipital poles, right orbital frontal lobe, and bilateral prefrontal lobes; significant decrease of DC in the bilateral primary motor cortex, bilateral sensory motor region, right prefrontal lobe, left bilateral precuneus, bilateral lateral temporal lobes, left cingulate cortex, and bilateral visual processing cortex. The DC's z-scores of right inferior occipital gyrus were significant negative correlated with the ALSFRS-r scores. Our findings confirm that the regions with abnormal network DC in ALS patients were located in multiple brain regions including primary motor, somatosensory and extra-motor areas, supporting the concept that ALS is a multisystem disorder. Specifically, our study found that DC in the visual areas was altered and ALS patients with higher DC in right inferior occipital gyrus have more severity of disease. The result demonstrated that the altered DC value in this region can probably be used to assess severity of ALS. PMID:27242409

  8. Adaptive re-tracking algorithm for retrieval of water level variations and wave heights from satellite altimetry data for middle-sized inland water bodies

    NASA Astrophysics Data System (ADS)

    Troitskaya, Yuliya; Lebedev, Sergey; Soustova, Irina; Rybushkina, Galina; Papko, Vladislav; Baidakov, Georgy; Panyutin, Andrey

    One of the recent applications of satellite altimetry originally designed for measurements of the sea level [1] is associated with remote investigation of the water level of inland waters: lakes, rivers, reservoirs [2-7]. The altimetry data re-tracking algorithms developed for open ocean conditions (e.g. Ocean-1,2) [1] often cannot be used in these cases, since the radar return is significantly contaminated by reflection from the land. The problem of minimization of errors in the water level retrieval for inland waters from altimetry measurements can be resolved by re-tracking satellite altimetry data. Recently, special re-tracking algorithms have been actively developed for re-processing altimetry data in the coastal zone when reflection from land strongly affects echo shapes: threshold re-tracking, The other methods of re-tracking (threshold re-tracking, beta-re-tracking, improved threshold re-tracking) were developed in [9-11]. The latest development in this field is PISTACH product [12], in which retracking bases on the classification of typical forms of telemetric waveforms in the coastal zones and inland water bodies. In this paper a novel method of regional adaptive re-tracking based on constructing a theoretical model describing the formation of telemetric waveforms by reflection from the piecewise constant model surface corresponding to the geography of the region is considered. It was proposed in [13, 14], where the algorithm for assessing water level in inland water bodies and in the coastal zone of the ocean with an error of about 10-15 cm was constructed. The algorithm includes four consecutive steps: - constructing a local piecewise model of a reflecting surface in the neighbourhood of the reservoir; - solving a direct problem by calculating the reflected waveforms within the framework of the model; - imposing restrictions and validity criteria for the algorithm based on waveform modelling; - solving the inverse problem by retrieving a tracking point

  9. DFT STUDIES OF HYDRATED CARBOHYDRATES: DFT MOLECULAR DYNAMICS SIMULATIONS AT THE B3LYP/6-31+G* LEVEL OF THEORY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several mono- and disaccharides have been studied by performing constant energy molecular dynamics at the B3LYP/6-31+G* + COSMO (solvation) level of theory, alpha-maltose is of particular interest as the variation in glycosidic dihedral angles is dependent upon the starting hydroxyl conformation. T...

  10. Using the Theory of Planned Behavior to Understand In-Service Kindergarten Teachers' Behavior to Enroll in a Graduate Level Academic Program

    ERIC Educational Resources Information Center

    Chen, I. Ju

    2007-01-01

    The main purpose of this study was to investigate and predict the behavioral intention of in-service Taiwanese kindergarten teachers regarding whether they would join a graduate level academic program. The research framework was based on the Theory of Planned Behavior (TPB) in order to identify the most influential component that affected their…

  11. Constant energy DFT molecular dynamics simulations of solvated carbohydrates at the B3LYP/6-31+G* level of theory

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The disaccharide, alpha/beta-maltose, has been studied using constant energy ab initio molecular dynamics at the B3LYP/6-31+G* COSMO (solvent) level of theory. Maltose is of particular interest as the variation in glycosidic dihedral angles is dependent upon the starting hydroxyl conformation. Tha...

  12. A Resource for Eliciting Student Alternative Conceptions: Examining the Adaptability of a Concept Inventory for Natural Selection at the Secondary School Level

    NASA Astrophysics Data System (ADS)

    Lucero, Margaret M.; Petrosino, Anthony J.

    2016-07-01

    The Conceptual Inventory of Natural Selection (CINS) is an example of a research-based instrument that assesses conceptual understanding in an area that contains well-documented alternative conceptions. Much of the CINS's use and original validation has been relegated to undergraduate settings, but the information learned from student responses on the CINS can also potentially be a useful resource for teachers at the secondary level. Because of its structure, the CINS can have a role in eliciting alternative conceptions and induce deeper conceptual understanding by having student ideas leveraged during instruction. In a first step toward this goal, the present study further investigated the CINS's internal properties by having it administered to a group (n = 339) of students among four different biology teachers at a predominantly Latino, economically disadvantaged high school. In addition, incidences of the concept inventory's use among the teachers' practices were collected for support of its adaptability at the secondary level. Despite the teachers' initial enthusiasm for the CINS's use as an assessment tool in the present study, results from a principal components analysis demonstrate inconsistencies between the original and present validations. Results also reveal how the teachers think CINS items may be revised for future use among secondary student populations.

  13. The Impact of Different Levels of Adaptive Iterative Dose Reduction 3D on Image Quality of 320-Row Coronary CT Angiography: A Clinical Trial

    PubMed Central

    Feger, Sarah; Rief, Matthias; Zimmermann, Elke; Martus, Peter; Schuijf, Joanne Désirée; Blobel, Jörg; Richter, Felicitas; Dewey, Marc

    2015-01-01

    Purpose The aim of this study was the systematic image quality evaluation of coronary CT angiography (CTA), reconstructed with the 3 different levels of adaptive iterative dose reduction (AIDR 3D) and compared to filtered back projection (FBP) with quantum denoising software (QDS). Methods Standard-dose CTA raw data of 30 patients with mean radiation dose of 3.2 ± 2.6 mSv were reconstructed using AIDR 3D mild, standard, strong and compared to FBP/QDS. Objective image quality comparison (signal, noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), contour sharpness) was performed using 21 measurement points per patient, including measurements in each coronary artery from proximal to distal. Results Objective image quality parameters improved with increasing levels of AIDR 3D. Noise was lowest in AIDR 3D strong (p≤0.001 at 20/21 measurement points; compared with FBP/QDS). Signal and contour sharpness analysis showed no significant difference between the reconstruction algorithms for most measurement points. Best coronary SNR and CNR were achieved with AIDR 3D strong. No loss of SNR or CNR in distal segments was seen with AIDR 3D as compared to FBP. Conclusions On standard-dose coronary CTA images, AIDR 3D strong showed higher objective image quality than FBP/QDS without reducing contour sharpness. Trial Registration Clinicaltrials.gov NCT00967876 PMID:25945924

  14. Elliptic Solvers with Adaptive Mesh Refinement on Complex Geometries

    SciTech Connect

    Phillip, B.

    2000-07-24

    Adaptive Mesh Refinement (AMR) is a numerical technique for locally tailoring the resolution computational grids. Multilevel algorithms for solving elliptic problems on adaptive grids include the Fast Adaptive Composite grid method (FAC) and its parallel variants (AFAC and AFACx). Theory that confirms the independence of the convergence rates of FAC and AFAC on the number of refinement levels exists under certain ellipticity and approximation property conditions. Similar theory needs to be developed for AFACx. The effectiveness of multigrid-based elliptic solvers such as FAC, AFAC, and AFACx on adaptively refined overlapping grids is not clearly understood. Finally, a non-trivial eye model problem will be solved by combining the power of using overlapping grids for complex moving geometries, AMR, and multilevel elliptic solvers.

  15. Identification and dual adaptive control of a turbojet engine

    NASA Technical Reports Server (NTRS)

    Merrill, W.; Leininger, G.

    1979-01-01

    The objective of this paper is to utilize the design methods of modern control theory to realize a dual-adaptive feedback control unit for a highly nonlinear single spool airbreathing turbojet engine. Using a very detailed and accurate simulation of the nonlinear engine as the data source, linear operating point models of unspecified dimension are identified. Feedback control laws are designed at each operating point for a prespecified set of sampling rates using sampled-data output regulator theory. The control system sampling rate is determined by an adaptive sampling algorithm in correspondence with turbojet engine performance. The result is a dual-adaptive control law that is functionally dependent upon the sampling rate selected and environmental operating conditions. Simulation transients demonstrate the utility of the dual-adaptive design to improve on-board computer utilization while maintaining acceptable levels of engine performance.

  16. An adaptive interpolation scheme for molecular potential energy surfaces.

    PubMed

    Kowalewski, Markus; Larsson, Elisabeth; Heryudono, Alfa

    2016-08-28

    The calculation of potential energy surfaces for quantum dynamics can be a time consuming task-especially when a high level of theory for the electronic structure calculation is required. We propose an adaptive interpolation algorithm based on polyharmonic splines combined with a partition of unity approach. The adaptive node refinement allows to greatly reduce the number of sample points by employing a local error estimate. The algorithm and its scaling behavior are evaluated for a model function in 2, 3, and 4 dimensions. The developed algorithm allows for a more rapid and reliable interpolation of a potential energy surface within a given accuracy compared to the non-adaptive version. PMID:27586901

  17. E-Learning, Multiple Intelligences Theory (MI) and Learner-Centred Instruction: Adapting MI Learning Theoretical Principles to the Instruction of Health and Safety to Construction Managers

    ERIC Educational Resources Information Center

    McNamee, Paul; Madden, Dave; McNamee, Frank; Wall, John; Hurst, Alan; Vrasidas, Charalambos; Chanquoy, Lucile; Baccino, Thierry; Acar, Emrah; Onwy-Yazici, Ela; Jordan, Ann

    2009-01-01

    This paper describes an ongoing EU project concerned with developing an instructional design framework for virtual classes (VC) that is based on the theory of Multiple Intelligences (MI) (1983). The psychological theory of Multiple Intelligences (Gardner 1983) has received much credence within instructional design since its inception and has been…

  18. Heat Shock Partially Dissociates the Overlapping Modules of the Yeast Protein-Protein Interaction Network: A Systems Level Model of Adaptation

    PubMed Central

    Mihalik, Ágoston; Csermely, Peter

    2011-01-01

    Network analysis became a powerful tool giving new insights to the understanding of cellular behavior. Heat shock, the archetype of stress responses, is a well-characterized and simple model of cellular dynamics. S. cerevisiae is an appropriate model organism, since both its protein-protein interaction network (interactome) and stress response at the gene expression level have been well characterized. However, the analysis of the reorganization of the yeast interactome during stress has not been investigated yet. We calculated the changes of the interaction-weights of the yeast interactome from the changes of mRNA expression levels upon heat shock. The major finding of our study is that heat shock induced a significant decrease in both the overlaps and connections of yeast interactome modules. In agreement with this the weighted diameter of the yeast interactome had a 4.9-fold increase in heat shock. Several key proteins of the heat shock response became centers of heat shock-induced local communities, as well as bridges providing a residual connection of modules after heat shock. The observed changes resemble to a ‘stratus-cumulus’ type transition of the interactome structure, since the unstressed yeast interactome had a globally connected organization, similar to that of stratus clouds, whereas the heat shocked interactome had a multifocal organization, similar to that of cumulus clouds. Our results showed that heat shock induces a partial disintegration of the global organization of the yeast interactome. This change may be rather general occurring in many types of stresses. Moreover, other complex systems, such as single proteins, social networks and ecosystems may also decrease their inter-modular links, thus develop more compact modules, and display a partial disintegration of their global structure in the initial phase of crisis. Thus, our work may provide a model of a general, system-level adaptation mechanism to environmental changes. PMID:22022244

  19. A first order theory of the p/+/-n-n/+/ edge-illuminated silicon solar cell at very high injection levels

    NASA Technical Reports Server (NTRS)

    Goradia, C.; Sater, B. L.

    1977-01-01

    A first order theory of the edge-illuminated p(+)-n-n(+) silicon solar cell under very high injection levels has been derived. The very high injection level illuminated J-V characteristic is derived for any general base width to diffusion length (W/L) ratio and it includes the minority carrier reflection by the n-n(+) high-low junction. The beneficial effects of the high-low junction are shown to be significant until extremely high injection levels are reached. The theoretical dependencies of Jsc and Voc on temperature, incident intensity, and base resistivity are derived and discussed in detail. Some experimental results are given and these are discussed in relation to the theory.

  20. Level-resolved quantum statistical theory of electron capture into many-electron compound resonances in highly charged ions

    NASA Astrophysics Data System (ADS)

    Berengut, J. C.; Harabati, C.; Dzuba, V. A.; Flambaum, V. V.; Gribakin, G. F.

    2015-12-01

    The strong mixing of many-electron basis states in excited atoms and ions with open f shells results in very large numbers of complex, chaotic eigenstates that cannot be computed to any degree of accuracy. Describing the processes which involve such states requires the use of a statistical theory. Electron capture into these "compound resonances" leads to electron-ion recombination rates that are orders of magnitude greater than those of direct, radiative recombination and cannot be described by standard theories of dielectronic recombination. Previous statistical theories considered this as a two-electron capture process which populates a pair of single-particle orbitals, followed by "spreading" of the two-electron states into chaotically mixed eigenstates. This method is similar to a configuration-average approach because it neglects potentially important effects of spectator electrons and conservation of total angular momentum. In this work we develop a statistical theory which considers electron capture into "doorway" states with definite angular momentum obtained by the configuration interaction method. We apply this approach to electron recombination with W20 +, considering 2 ×106 doorway states. Despite strong effects from the spectator electrons, we find that the results of the earlier theories largely hold. Finally, we extract the fluorescence yield (the probability of photoemission and hence recombination) by comparison with experiment.

  1. Sustained effects of adaptation on the perception of familiar faces.

    PubMed

    Carbon, Claus-Christian; Ditye, Thomas

    2011-06-01

    Figural aftereffects are commonly believed to be transient and to fade away in the course of milliseconds. We tested face aftereffects using familiar faces and found sustained effects lasting up to 1 week. In 3 experiments, participants were first exposed to distorted pictures of famous persons and then had to select the veridical face in a 2-alternative forced choice task. Veridicality aftereffects were found in a direction opposite to the adapting distortion; these effects generalized to other pictures of the same individual and also to pictures of celebrities that had not been shown during adaptation. The findings support hierarchical theories of norm-based face coding and suggest that face adaptation effects have a representational basis. They also point toward multiple timescales in the operation of adaptation mechanisms, thereby providing a link between high-level adaptation and more general aspects of neuro-cognitive plasticity, that is, learning and memory. PMID:20731521

  2. Computer-aided detection of colonic polyps with level set-based adaptive convolution in volumetric mucosa to advance CT colonography toward a screening modality

    PubMed Central

    Zhu, Hongbin; Duan, Chaijie; Pickhardt, Perry; Wang, Su; Liang, Zhengrong

    2009-01-01

    As a promising second reader of computed tomographic colonography (CTC) screening, the computer-aided detection (CAD) of colonic polyps has earned fast growing research interest. In this paper, we present a CAD scheme to automatically detect colonic polyps in CTC images. First, a thick colon wall representation, ie, a volumetric mucosa (VM) with several voxels wide in general, was segmented from CTC images by a partial-volume image segmentation algorithm. Based on the VM, we employed a level set-based adaptive convolution method for calculating the first- and second-order spatial derivatives more accurately to start the geometric analysis. Furthermore, to emphasize the correspondence among different layers in the VM, we introduced a middle-layer enhanced integration along the image gradient direction inside the VM to improve the operation of extracting the geometric information, like the principal curvatures. Initial polyp candidates (IPCs) were then determined by thresholding the geometric measurements. Based on IPCs, several features were extracted for each IPC, and fed into a support vector machine to reduce false positives (FPs). The final detections were displayed in a commercial system to provide second opinions for radiologists. The CAD scheme was applied to 26 patient CTC studies with 32 confirmed polyps by both optical and virtual colonoscopies. Compared to our previous work, all the polyps can be detected successfully with less FPs. At the 100% by polyp sensitivity, the new method yielded 3.5 FPs/dataset. PMID:20428331

  3. The Professional Context as a Predictor for Response Distortion in the Adaption-Innovation Inventory--An Investigation Using Mixture Distribution Item Response Theory Models

    ERIC Educational Resources Information Center

    Fischer, Sebastian; Freund, Philipp Alexander

    2014-01-01

    The Adaption-Innovation Inventory (AII), originally developed by Kirton (1976), is a widely used self-report instrument for measuring problem-solving styles at work. The present study investigates how scores on the AII are affected by different response styles. Data are collected from a combined sample (N = 738) of students, employees, and…

  4. A Monte Carlo Simulation Investigating the Validity and Reliability of Ability Estimation in Item Response Theory with Speeded Computer Adaptive Tests

    ERIC Educational Resources Information Center

    Schmitt, T. A.; Sass, D. A.; Sullivan, J. R.; Walker, C. M.

    2010-01-01

    Imposed time limits on computer adaptive tests (CATs) can result in examinees having difficulty completing all items, thus compromising the validity and reliability of ability estimates. In this study, the effects of speededness were explored in a simulated CAT environment by varying examinee response patterns to end-of-test items. Expectedly,…

  5. A Teaching-Learning Sequence for the Special Relativity Theory at High School Level Historically and Epistemologically Contextualized

    ERIC Educational Resources Information Center

    Arriassecq, Irene; Greca, Ileana Maria

    2012-01-01

    This paper discusses some topics that stem from recent contributions made by the History, the Philosophy, and the Didactics of Science. We consider these topics relevant to the introduction of the Special Relativity Theory (SRT) in high school within a contextualized approach. We offer an outline of a teaching-learning sequence dealing with the…

  6. Teaching Evolution at A-Level: Is "Intelligent Design" a Scientific Theory That Merits Inclusion in the Biology Syllabus?

    ERIC Educational Resources Information Center

    Freeland, Peter

    2013-01-01

    Charles Darwin supposed that evolution involved a process of gradual change, generated randomly, with the selection and retention over many generations of survival-promoting features. Some theists have never accepted this idea. "Intelligent design" is a relatively recent theory, supposedly based on scientific evidence, which attempts to…

  7. Dynamical Adaptation in Terrorist Cells/Networks

    NASA Astrophysics Data System (ADS)

    Hussain, D. M. Akbar; Ahmed, Zaki

    Typical terrorist cells/networks have dynamical structure as they evolve or adapt to changes which may occur due to capturing or killing of a member of the cell/network. Analytical measures in graph theory like degree centrality, betweenness and closeness centralities are very common and have long history of their successful use in revealing the importance of various members of the network. However, modeling of covert, terrorist or criminal networks through social graph dose not really provide the hierarchical structure which exist in these networks as these networks are composed of leaders and followers etc. In this research we analyze and predict the most likely role a particular node can adapt once a member of the network is either killed or caught. The adaptation is based on computing Bayes posteriori probability of each node and the level of the said node in the network structure.

  8. [The kinetic theory of the aging of living systems].

    PubMed

    Viktorov, A A; Kholodnov, V A

    2013-01-01

    Kinetic theory of aging of living systems is proposed. Theory is based on the concept of continuous adaptation of biological system (BS) from its birth to changing conditions of environment (ENV). Adaptation rate as rate of risk of destructions accumulation in BS is studied as competition between two simultaneous processes: BS destruction and recombination of damages defined by kinetics of autocatalytic chemical reactions. Kinetic theory assumes critical phenomenon: failure of adaptation when intensity of ENV impact becomes higher some critical level. Choice of parameters of kinetic mathematical model and accounting dependence of ENV impact intensity on time allows describing the following results observed in medical practice: child mortality, depletion of adaptive reserves, slowing the rate of aging of long-living persons, damped harmonic oscillations of biological response at pulse toxic intervention and to estimate risks of disease and death. PMID:24003729

  9. The Use of Thought Experiments in Teaching Physics to Upper Secondary-Level Students: Two examples from the theory of relativity

    NASA Astrophysics Data System (ADS)

    Velentzas, Athanasios; Halkia, Krystallia

    2013-12-01

    The present study focuses on the way thought experiments (TEs) can be used as didactical tools in teaching physics to upper secondary-level students. A qualitative study was designed to investigate to what extent the TEs called 'Einstein's elevator' and 'Einstein's train' can function as tools in teaching basic concepts of the theory of relativity to upper secondary-level students. The above TEs were used in the form they are presented by Einstein himself and by Landau and Rumer in books that popularize theories of physics. The research sample consisted of 40 Greek students, divided into 11 groups of three to four students each. The findings of this study reveal that the use of TEs in teaching the theory of relativity can help students realize situations which refer to a world beyond their everyday experience and develop syllogisms according to the theory. In this way, students can grasp physics laws and principles which demand a high degree of abstract thinking, such as the principle of equivalence and the consequences of the constancy of the speed of light to concepts of time and space.

  10. Simple method for model reference adaptive control

    NASA Technical Reports Server (NTRS)

    Seraji, H.

    1989-01-01

    A simple method is presented for combined signal synthesis and parameter adaptation within the framework of model reference adaptive control theory. The results are obtained using a simple derivation based on an improved Liapunov function.

  11. Hybrid Adaptive Flight Control with Model Inversion Adaptation

    NASA Technical Reports Server (NTRS)

    Nguyen, Nhan

    2011-01-01

    This study investigates a hybrid adaptive flight control method as a design possibility for a flight control system that can enable an effective adaptation strategy to deal with off-nominal flight conditions. The hybrid adaptive control blends both direct and indirect adaptive control in a model inversion flight control architecture. The blending of both direct and indirect adaptive control provides a much more flexible and effective adaptive flight control architecture than that with either direct or indirect adaptive control alone. The indirect adaptive control is used to update the model inversion controller by an on-line parameter estimation of uncertain plant dynamics based on two methods. The first parameter estimation method is an indirect adaptive law based on the Lyapunov theory, and the second method is a recursive least-squares indirect adaptive law. The model inversion controller is therefore made to adapt to changes in the plant dynamics due to uncertainty. As a result, the modeling error is reduced that directly leads to a decrease in the tracking error. In conjunction with the indirect adaptive control that updates the model inversion controller, a direct adaptive control is implemented as an augmented command to further reduce any residual tracking error that is not entirely eliminated by the indirect adaptive control.

  12. Modeling the zonal disintegration of rocks near deep level tunnels by gradient internal variable continuous phase transition theory

    NASA Astrophysics Data System (ADS)

    Haoxiang, Chen; Qi, Chengzhi; Peng, Liu; Kairui, Li; Aifantis, Elias C.

    2015-12-01

    The occurrence of alternating damage zones surrounding underground openings (commonly known as zonal disintegration) is treated as a "far from thermodynamic equilibrium" dynamical process or a nonlinear continuous phase transition phenomenon. The approach of internal variable gradient theory with diffusive transport, which may be viewed as a subclass of Landau's phase transition theory, is adopted. The order parameter is identified with an irreversible strain quantity, the gradient of which enters into the expression for the free energy of the rock system. The gradient term stabilizes the material behavior in the post-softening regime, where zonal disintegration occurs. The results of a simplified linearized analysis are confirmed by the numerical solution of the nonlinear problem.

  13. Topics in N = 1 supergravity in four dimensions and superstring effective field theories beyond tree-level

    SciTech Connect

    Saririan, K.

    1997-05-01

    In this thesis, the author presents some works in the direction of studying quantum effects in locally supersymmetric effective field theories that appear in the low energy limit of superstring theory. After reviewing the Kaehler covariant formulation of supergravity, he shows the calculation of the divergent one-loop contribution to the effective boson Lagrangian for supergravity, including the Yang-Mills sector and the helicity-odd operators that arise from integration over fermion fields. The only restriction is on the Yang-Mills kinetic energy normalization function, which is taken diagonal in gauge indices, as in models obtained from superstrings. He then presents the full result for the divergent one-loop contribution to the effective boson Lagrangian for supergravity coupled to chiral and Yang-Mills supermultiplets. He also considers the specific case of dilaton couplings in effective supergravity Lagrangians from superstrings, for which the one-loop result is considerably simplified. He studies gaugino condensation in the presence of an intermediate mass scale in the hidden sector. S-duality is imposed as an approximate symmetry of the effective supergravity theory. Furthermore, the author includes in the Kaehler potential the renormalization of the gauge coupling and the one-loop threshold corrections at the intermediate scale. It is shown that confinement is indeed achieved. Furthermore, a new running behavior of the dilaton arises which he attributes to S-duality. He also discusses the effects of the intermediate scale, and possible phenomenological implications of this model.

  14. Adaptation of health care for migrants: whose responsibility?

    PubMed Central

    2014-01-01

    Background In a context of increasing ethnic diversity, culturally competent strategies have been recommended to improve care quality and access to health care for ethnic minorities and migrants; their implementation by health professionals, however, has remained patchy. Most programs of cultural competence assume that health professionals accept that they have a responsibility to adapt to migrants, but this assumption has often remained at the level of theory. In this paper, we surveyed health professionals’ views on their responsibility to adapt. Methods Five hundred-and-sixty-nine health professionals from twenty-four inpatient and outpatient health services were selected according to their geographic location. All health care professionals were requested to complete a questionnaire about who should adapt to ethnic diversity: health professionals or patients. After a factorial analysis to identify the underlying responsibility dimensions, we performed a multilevel regression model in order to investigate individual and service covariates of responsibility attribution. Results Three dimensions emerged from the factor analysis: responsibility for the adaptation of communication, responsibility for the adaptation to the negotiation of values, and responsibility for the adaptation to health beliefs. Our results showed that the sense of responsibility for the adaptation of health care depended on the nature of the adaptation required: when the adaptation directly concerned communication with the patient, health professionals declared that they should be the ones to adapt; in relation to cultural preferences, however, the responsibility felt on the patient’s shoulders. Most respondents were unclear in relation to adaptation to health beliefs. Regression indicated that being Belgian, not being a physician, and working in a primary-care service were associated with placing the burden of responsibility on the patient. Conclusions Health care professionals do not

  15. Analysis of transition state stabilization by non-covalent interactions in the Houk-List model of organocatalyzed intermolecular Aldol additions using functional-group symmetry-adapted perturbation theory.

    PubMed

    Bakr, Brandon W; Sherrill, C David

    2016-04-21

    Rational design of catalysts would be aided by a better understanding of how non-covalent interactions stabilize transition states. Here, we apply the newly-developed Functional-Group Symmetry-Adapted Perturbation Theory (F-SAPT) to quantify non-covalent interactions in transition states of the proline-catalyzed intermolecular aldol reaction between benzaldehyde and cyclohexanone, according to the Houk-List mechanism [Bahmanyar et al., J. Am. Chem. Soc., 2003, 125, 2475]. A recent re-examination of this organocatalytic reaction by Rzepa and co-workers [Armstrong et al., Chem. Sci., 2014, 5, 2057] used electron density analysis to identify three key non-covalent interactions thought to influence stereoselectivity: (1) a favorable electrostatic interaction (originally identified by Houk and List) between the NCH(δ+) group of the enamine intermediate and the (δ-)O[double bond, length as m-dash]C of benzaldehyde; (2) a C-H/π interaction between the cyclohexene group of the enamine intermediate and the benzaldehyde phenyl ring; (3) a stabilizing contact between an ortho-hydrogen of the phenyl and an oxygen of the carboxylic acid group of the enamine. These three interactions have been directly computed using F-SAPT, which confirms the stabilizing interaction between an ortho-hydrogen and the carboxylic acid in the (S,S) and (R,S) transition state stereoisomers. F-SAPT analysis also finds stabilizing dispersion and electrostatic interactions due to a C-H/π interaction between the cyclohexene and phenyl groups in the (S,S) and (R,R) transition states. However, unfavorable exchange-repulsion cancels the attractive terms that favor these stereoisomers. Surprisingly, the interaction thought to be most important for stereoselectivity, the NCH(δ+)(δ-)O[double bond, length as m-dash]C interaction, is actually found to be repulsive due to the negative charge on the nitrogen. Hence, our results indicate that geometric analysis and/or density-based analysis does not

  16. Coordinate Changes in Histone Modifications, mRNA Levels, and Metabolite Profiles in Clonal INS-1 832/13 β-Cells Accompany Functional Adaptations to Lipotoxicity*

    PubMed Central

    Malmgren, Siri; Spégel, Peter; Danielsson, Anders P.H.; Nagorny, Cecilia L.; Andersson, Lotta E.; Nitert, Marloes Dekker; Ridderstråle, Martin; Mulder, Hindrik; Ling, Charlotte

    2013-01-01

    Lipotoxicity is a presumed pathogenetic process whereby elevated circulating and stored lipids in type 2 diabetes cause pancreatic β-cell failure. To resolve the underlying molecular mechanisms, we exposed clonal INS-1 832/13 β-cells to palmitate for 48 h. We observed elevated basal insulin secretion but impaired glucose-stimulated insulin secretion in palmitate-exposed cells. Glucose utilization was unchanged, palmitate oxidation was increased, and oxygen consumption was impaired. Halting exposure of the clonal INS-1 832/13 β-cells to palmitate largely recovered all of the lipid-induced functional changes. Metabolite profiling revealed profound but reversible increases in cellular lipids. Glucose-induced increases in tricarboxylic acid cycle intermediates were attenuated by exposure to palmitate. Analysis of gene expression by microarray showed increased expression of 982 genes and decreased expression of 1032 genes after exposure to palmitate. Increases were seen in pathways for steroid biosynthesis, cell cycle, fatty acid metabolism, DNA replication, and biosynthesis of unsaturated fatty acids; decreases occurred in the aminoacyl-tRNA synthesis pathway. The activity of histone-modifying enzymes and histone modifications of differentially expressed genes were reversibly altered upon exposure to palmitate. Thus, Insig1, Lss, Peci, Idi1, Hmgcs1, and Casr were subject to epigenetic regulation. Our analyses demonstrate that coordinate changes in histone modifications, mRNA levels, and metabolite profiles accompanied functional adaptations of clonal β-cells to lipotoxicity. It is highly likely that these changes are pathogenetic, accounting for loss of glucose responsiveness and perturbed insulin secretion. PMID:23476019

  17. Coordinate changes in histone modifications, mRNA levels, and metabolite profiles in clonal INS-1 832/13 β-cells accompany functional adaptations to lipotoxicity.

    PubMed

    Malmgren, Siri; Spégel, Peter; Danielsson, Anders P H; Nagorny, Cecilia L; Andersson, Lotta E; Nitert, Marloes Dekker; Ridderstråle, Martin; Mulder, Hindrik; Ling, Charlotte

    2013-04-26

    Lipotoxicity is a presumed pathogenetic process whereby elevated circulating and stored lipids in type 2 diabetes cause pancreatic β-cell failure. To resolve the underlying molecular mechanisms, we exposed clonal INS-1 832/13 β-cells to palmitate for 48 h. We observed elevated basal insulin secretion but impaired glucose-stimulated insulin secretion in palmitate-exposed cells. Glucose utilization was unchanged, palmitate oxidation was increased, and oxygen consumption was impaired. Halting exposure of the clonal INS-1 832/13 β-cells to palmitate largely recovered all of the lipid-induced functional changes. Metabolite profiling revealed profound but reversible increases in cellular lipids. Glucose-induced increases in tricarboxylic acid cycle intermediates were attenuated by exposure to palmitate. Analysis of gene expression by microarray showed increased expression of 982 genes and decreased expression of 1032 genes after exposure to palmitate. Increases were seen in pathways for steroid biosynthesis, cell cycle, fatty acid metabolism, DNA replication, and biosynthesis of unsaturated fatty acids; decreases occurred in the aminoacyl-tRNA synthesis pathway. The activity of histone-modifying enzymes and histone modifications of differentially expressed genes were reversibly altered upon exposure to palmitate. Thus, Insig1, Lss, Peci, Idi1, Hmgcs1, and Casr were subject to epigenetic regulation. Our analyses demonstrate that coordinate changes in histone modifications, mRNA levels, and metabolite profiles accompanied functional adaptations of clonal β-cells to lipotoxicity. It is highly likely that these changes are pathogenetic, accounting for loss of glucose responsiveness and perturbed insulin secretion. PMID:23476019

  18. Parallel Anisotropic Tetrahedral Adaptation

    NASA Technical Reports Server (NTRS)

    Park, Michael A.; Darmofal, David L.

    2008-01-01

    An adaptive method that robustly produces high aspect ratio tetrahedra to a general 3D metric specification without introducing hybrid semi-structured regions is presented. The elemental operators and higher-level logic is described with their respective domain-decomposed parallelizations. An anisotropic tetrahedral grid adaptation scheme is demonstrated for 1000-1 stretching for a simple cube geometry. This form of adaptation is applicable to more complex domain boundaries via a cut-cell approach as demonstrated by a parallel 3D supersonic simulation of a complex fighter aircraft. To avoid the assumptions and approximations required to form a metric to specify adaptation, an approach is introduced that directly evaluates interpolation error. The grid is adapted to reduce and equidistribute this interpolation error calculation without the use of an intervening anisotropic metric. Direct interpolation error adaptation is illustrated for 1D and 3D domains.

  19. Gravitational adaptation of animals

    NASA Technical Reports Server (NTRS)

    Smith, A. H.; Burton, R. R.

    1982-01-01

    The effect of gravitational adaptation is studied in a group of five Leghorn cocks which had become physiologically adapted to 2 G after 162 days of centrifugation. After this period of adaptation, they are periodically exposed to a 2 G field, accompanied by five previously unexposed hatch-mates, and the degree of retained acceleration adaptation is estimated from the decrease in lymphocyte frequency after 24 hr at 2 G. Results show that the previously adapted birds exhibit an 84% greater lymphopenia than the unexposed birds, and that the lymphocyte frequency does not decrease to a level below that found at the end of 162 days at 2 G. In addition, the capacity for adaptation to chronic acceleration is found to be highly heritable. An acceleration tolerant strain of birds shows lesser mortality during chronic acceleration, particularly in intermediate fields, although the result of acceleration selection is largely quantitative (a greater number of survivors) rather than qualitative (behavioral or physiological changes).

  20. Adaptive Computerized Instruction.

    ERIC Educational Resources Information Center

    Ray, Roger D.; And Others

    1995-01-01

    Describes an artificially intelligent multimedia computerized instruction system capable of developing a conceptual image of what a student is learning while the student is learning it. It focuses on principles of learning and adaptive behavioral control systems theory upon which the system is designed and demonstrates multiple user modes.…