WorldWideScience

Sample records for state evolution model

  1. [Modeling asthma evolution by a multi-state model].

    Science.gov (United States)

    Boudemaghe, T; Daurès, J P

    2000-06-01

    There are many scores for the evaluation of asthma. However, most do not take into account the evolutionary aspects of this illness. We propose a model for the clinical course of asthma by a homogeneous Markov model process based on data provided by the A.R.I.A. (Association de Recherche en Intelligence Artificielle dans le cadre de l'asthme et des maladies respiratoires). The criterion used is the activity of the illness during the month before consultation. The activity is divided into three levels: light (state 1), mild (state 2) and severe (state 3). The model allows the evaluation of the strength of transition between states. We found that strong intensities were implicated towards state 2 (lambda(12) and lambda(32)), less towards state 1 (lambda(21) and lambda(31)), and minimum towards state 3 (lambda(23)). This results in an equilibrium distribution essentially divided between state 1 and 2 (44.6% and 51.0% respectively) with a small proportion in state 3 (4.4%). In the future, the increasing amount of available data should permit the introduction of covariables, the distinction of subgroups and the implementation of clinical studies. The interest of this model falls within the domain of the quantification of the illness as well as the representation allowed thereof, while offering a formal framework for the clinical notion of time and evolution.

  2. Evolution analysis of the states of the EZ model

    International Nuclear Information System (INIS)

    Qing-Hua, Chen; Yi-Ming, Ding; Hong-Guang, Dong

    2009-01-01

    Based on suitable choice of states, this paper studies the stability of the equilibrium state of the EZ model by regarding the evolution of the EZ model as a Markov chain and by showing that the Markov chain is ergodic. The Markov analysis is applied to the EZ model with small number of agents, the exact equilibrium state for N = 5 and numerical results for N = 18 are obtained. (cross-disciplinary physics and related areas of science and technology)

  3. A microscopic model of rate and state friction evolution

    Science.gov (United States)

    Li, Tianyi; Rubin, Allan M.

    2017-08-01

    Whether rate- and state-dependent friction evolution is primarily slip dependent or time dependent is not well resolved. Although slide-hold-slide experiments are traditionally interpreted as supporting the aging law, implying time-dependent evolution, recent studies show that this evidence is equivocal. In contrast, the slip law yields extremely good fits to velocity step experiments, although a clear physical picture for slip-dependent friction evolution is lacking. We propose a new microscopic model for rate and state friction evolution in which each asperity has a heterogeneous strength, with individual portions recording the velocity at which they became part of the contact. Assuming an exponential distribution of asperity sizes on the surface, the model produces results essentially similar to the slip law, yielding very good fits to velocity step experiments but not improving much the fits to slide-hold-slide experiments. A numerical kernel for the model is developed, and an analytical expression is obtained for perfect velocity steps, which differs from the slip law expression by a slow-decaying factor. By changing the quantity that determines the intrinsic strength, we use the same model structure to investigate aging-law-like time-dependent evolution. Assuming strength to increase logarithmically with contact age, for two different definitions of age we obtain results for velocity step increases significantly different from the aging law. Interestingly, a solution very close to the aging law is obtained if we apply a third definition of age that we consider to be nonphysical. This suggests that under the current aging law, the state variable is not synonymous with contact age.

  4. Charge state evolution in the solar wind. III. Model comparison with observations

    Energy Technology Data Exchange (ETDEWEB)

    Landi, E.; Oran, R.; Lepri, S. T.; Zurbuchen, T. H.; Fisk, L. A.; Van der Holst, B. [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, MI 48109 (United States)

    2014-08-01

    We test three theoretical models of the fast solar wind with a set of remote sensing observations and in-situ measurements taken during the minimum of solar cycle 23. First, the model electron density and temperature are compared to SOHO/SUMER spectroscopic measurements. Second, the model electron density, temperature, and wind speed are used to predict the charge state evolution of the wind plasma from the source regions to the freeze-in point. Frozen-in charge states are compared with Ulysses/SWICS measurements at 1 AU, while charge states close to the Sun are combined with the CHIANTI spectral code to calculate the intensities of selected spectral lines, to be compared with SOHO/SUMER observations in the north polar coronal hole. We find that none of the theoretical models are able to completely reproduce all observations; namely, all of them underestimate the charge state distribution of the solar wind everywhere, although the levels of disagreement vary from model to model. We discuss possible causes of the disagreement, namely, uncertainties in the calculation of the charge state evolution and of line intensities, in the atomic data, and in the assumptions on the wind plasma conditions. Last, we discuss the scenario where the wind is accelerated from a region located in the solar corona rather than in the chromosphere as assumed in the three theoretical models, and find that a wind originating from the corona is in much closer agreement with observations.

  5. Charge state evolution in the solar wind. III. Model comparison with observations

    International Nuclear Information System (INIS)

    Landi, E.; Oran, R.; Lepri, S. T.; Zurbuchen, T. H.; Fisk, L. A.; Van der Holst, B.

    2014-01-01

    We test three theoretical models of the fast solar wind with a set of remote sensing observations and in-situ measurements taken during the minimum of solar cycle 23. First, the model electron density and temperature are compared to SOHO/SUMER spectroscopic measurements. Second, the model electron density, temperature, and wind speed are used to predict the charge state evolution of the wind plasma from the source regions to the freeze-in point. Frozen-in charge states are compared with Ulysses/SWICS measurements at 1 AU, while charge states close to the Sun are combined with the CHIANTI spectral code to calculate the intensities of selected spectral lines, to be compared with SOHO/SUMER observations in the north polar coronal hole. We find that none of the theoretical models are able to completely reproduce all observations; namely, all of them underestimate the charge state distribution of the solar wind everywhere, although the levels of disagreement vary from model to model. We discuss possible causes of the disagreement, namely, uncertainties in the calculation of the charge state evolution and of line intensities, in the atomic data, and in the assumptions on the wind plasma conditions. Last, we discuss the scenario where the wind is accelerated from a region located in the solar corona rather than in the chromosphere as assumed in the three theoretical models, and find that a wind originating from the corona is in much closer agreement with observations.

  6. Time evolution of one-dimensional gapless models from a domain wall initial state: stochastic Loewner evolution continued?

    International Nuclear Information System (INIS)

    Calabrese, Pasquale; Hagendorf, Christian; Doussal, Pierre Le

    2008-01-01

    We study the time evolution of quantum one-dimensional gapless systems evolving from initial states with a domain wall. We generalize the path integral imaginary time approach that together with boundary conformal field theory allows us to derive the time and space dependence of general correlation functions. The latter are explicitly obtained for the Ising universality class, and the typical behavior of one- and two-point functions is derived for the general case. Possible connections with the stochastic Loewner evolution are discussed and explicit results for one-point time dependent averages are obtained for generic κ for boundary conditions corresponding to stochastic Loewner evolution. We use this set of results to predict the time evolution of the entanglement entropy and obtain the universal constant shift due to the presence of a domain wall in the initial state

  7. Neutron star evolutions using tabulated equations of state with a new execution model

    Science.gov (United States)

    Anderson, Matthew; Kaiser, Hartmut; Neilsen, David; Sterling, Thomas

    2012-03-01

    The addition of nuclear and neutrino physics to general relativistic fluid codes allows for a more realistic description of hot nuclear matter in neutron star and black hole systems. This additional microphysics requires that each processor have access to large tables of data, such as equations of state, and in large simulations the memory required to store these tables locally can become excessive unless an alternative execution model is used. In this talk we present neutron star evolution results obtained using a message driven multi-threaded execution model known as ParalleX as an alternative to using a hybrid MPI-OpenMP approach. ParalleX provides the user a new way of computation based on message-driven flow control coordinated by lightweight synchronization elements which improves scalability and simplifies code development. We present the spectrum of radial pulsation frequencies for a neutron star with the Shen equation of state using the ParalleX execution model. We present performance results for an open source, distributed, nonblocking ParalleX-based tabulated equation of state component capable of handling tables that may even be too large to read into the memory of a single node.

  8. State parameter-based modelling of microstructure evolution in micro-alloyed steel during hot forming

    International Nuclear Information System (INIS)

    Buken, H; Kozeschnik, E

    2016-01-01

    In steel production, thermo-mechanical treatment at elevated temperatures is an inevitable step for controlling the microstructure and, thus, the mechanical-technological properties of the final product. One of the main goals in modelling microstructure evolution is the prediction of progress and interaction of hardening and softening mechanism at temperatures, where reheating, hot rolling, finish rolling and coiling are typically carried out. The main mechanisms that need to be accounted for are precipitation, grain growth, solute drag, recovery, recrystallization and phase transformation, which are to be described as functions of temperature, external loading and chemical composition of the material. In the present work, we present a new approach for dealing with these problems and apply it to the thermal and mechanical loading of microalloyed steel. Within this model, we quantitatively predict, for instance, the phenomenon of recrystallization stop in the presence of precipitation. The computational treatment is verified against experimental data from literature, where good agreement is achieved. (paper)

  9. State DOT mission evolution.

    Science.gov (United States)

    2013-04-01

    This paper highlights the challenges faced by six state departments of transportation (California, Colorado, Florida, Massachusetts, Missouri, Oregon) and the views of their respective chief executive officers within the context of national trends. E...

  10. Persistence and Evolutions of the Rentier State Model in Gulf Countries

    International Nuclear Information System (INIS)

    Ozyavuz, Anais; Schmid, Dorothee

    2015-04-01

    A general economic model of understanding Middle Eastern states was elaborated by political scientists around the 1980's, based on the concept of rent. Rent derived from the exploitations and sales of natural resources (mainly crude-oil and gas reserves for the Middle-East area) became a new factor of wealth around which the economic model as much as the governance of energy-rich countries was reorganized. The particular case of GCC's countries as rentier state has been at the cornerstone of this concept since they own the most important share of energy resources in the world. Despite bringing high revenues to resource-abundant countries, rent clearly has a bad reputation, implying a system of 'allocative state' vs. 'productive state'. After four decades of the concept's circulation, the historicity of the rentier state theory clearly requires discussion. This paper will first deal with the emergence of the concept of rent in Gulf countries, and will study in which extend GCC member states have undertaken reforms and changes for depending less on oil-wealth and for reaching a more diversified economy. Despite their efforts and achievements - both endogenous as exogenous factors - are still inhibiting the development processes in each country. The improvements of the economy and the governance in those 6 countries have been - and will be - important not only for the concerned countries but also for the development and especially the stability of the Middle-East area. This last concern is definitely the main issue of last months for the area, being in the chaos since the emergence of a new regional player, the terrorist group Daesh. (author)

  11. Modelling microstructural evolution under irradiation

    International Nuclear Information System (INIS)

    Tikare, V.

    2015-01-01

    Microstructural evolution of materials under irradiation is characterised by some unique features that are not typically present in other application environments. While much understanding has been achieved by experimental studies, the ability to model this microstructural evolution for complex materials states and environmental conditions not only enhances understanding, it also enables prediction of materials behaviour under conditions that are difficult to duplicate experimentally. Furthermore, reliable models enable designing materials for improved engineering performance for their respective applications. Thus, development and application of mesoscale microstructural model are important for advancing nuclear materials technologies. In this chapter, the application of the Potts model to nuclear materials will be reviewed and demonstrated, as an example of microstructural evolution processes. (author)

  12. Modeling shoreface profile evolution

    NARCIS (Netherlands)

    Stive, M.J.F.; De Vriend, H.J.

    1995-01-01

    Current knowledge of hydro-, sediment and morpho-dynamics in the shoreface environment is insufficient to undertake shoreface-profile evolution modelling on the basis of first physical principles. We propose a simple, panel-type model to map observed behaviour. The internal dynamics are determined

  13. Modelling shoreface profile evolution

    NARCIS (Netherlands)

    Stive, Marcel J.F.; de Vriend, Huib J.

    1995-01-01

    Current knowledge of hydro-, sediment and morpho-dynamics in the shoreface environment is insufficient to undertake shoreface-profile evolution modelling on the basis of first physical principles. We propose a simple, panel-type model to map observed behaviour. The internal dynamics are determined

  14. Evolution of Business Models

    DEFF Research Database (Denmark)

    Antero, Michelle C.; Hedman, Jonas; Henningsson, Stefan

    2013-01-01

    The ERP industry has undergone dramatic changes over the past decades due to changing market demands, thereby creating new challenges and opportunities, which have to be managed by ERP vendors. This paper inquires into the necessary evolution of business models in a technology-intensive industry (e...

  15. Online transition matrix identification of the state evolution model for the extended Kalman filter in electrical impedance tomography

    International Nuclear Information System (INIS)

    Moura, Fernando S; Aya, Julio C C; Lima, Raul G; Fleury, Agenor T

    2008-01-01

    One of the electrical impedance tomography objectives is to estimate the electrical resistivity distribution in a domain based only on contour electrical potential measurements caused by an imposed electrical current distribution into the boundary. In biomedical applications, the random walk model is frequently used as evolution model and, under this conditions, it is observed poor tracking ability of the Extended Kalman Filter (EKF). An analytically developed evolution model is not feasible at this moment. The present work investigates the possibility of identifying the evolution model in parallel to the EKF and updating the evolution model with certain periodicity. The evolution model is identified using the history of resistivity distribution obtained by a sensitivity matrix based algorithm. To numerically identify the linear evolution model, it is used the Ibrahim Time Domain Method, normally used to identify the transition matrix on structural dynamics. The investigation was performed by numerical simulations of a time varying domain with the addition of noise. Numerical dificulties to compute the transition matrix were solved using a Tikhonov regularization. The EKF numerical simulations suggest that the tracking ability is significantly improved.

  16. Evolution of the Russian Model of Statehood in a Foreshortening of State and Church Relations: Traditional and Innovative Components

    Directory of Open Access Journals (Sweden)

    Alexandra A. Dorskaya

    2016-06-01

    Full Text Available In this article author showed a role of the state and church relations in evolution of the Russian statehood. Value of a religious factor in determination of the place of the Russian state on the international scene is analyzed. On specific examples value of state and confessional interaction in the legal sphere is shown. In the conclusion the author draws a conclusion that the state and church relations played an important role evolutions of the Russian statehood. In interaction of the Russian state and Russian Orthodox Church there are so-called traditions the moments (interaction during the periods of testing, wars, joint care of the social sphere, accounting of the international factor and innovative, connected with implementation of the principle of the secular state and human rights protection.

  17. Modeling SOL evolution during disruptions

    International Nuclear Information System (INIS)

    Rognlien, T.D.; Cohen, R.H.; Crotinger, J.A.

    1996-01-01

    We present the status of our models and transport simulations of the 2-D evolution of the scrape-off layer (SOL) during tokamak disruptions. This evolution is important for several reasons: It determines how the power from the core plasma is distributed on material surfaces, how impurities from those surfaces or from gas injection migrate back to the core region, and what are the properties of the SOL for carrying halo currents. We simulate this plasma in a time-dependent fashion using the SOL transport code UEDGE. This code models the SOL plasma using fluid equations of plasma density, parallel momentum (along the magnetic field), electron energy, ion energy, and neutral gas density. A multispecies model is used to follow the density of different charge-states of impurities. The parallel transport is classical but with kinetic modifications; these are presently treated by flux limits, but we have initiated more sophisticated models giving the correct long-mean-free path limit. The cross-field transport is anomalous, and one of the results of this work is to determine reasonable values to characterize disruptions. Our primary focus is on the initial thermal quench phase when most of the core energy is lost, but the total current is maintained. The impact of edge currents on the MHD equilibrium will be discussed

  18. TMDs: Evolution, modeling, precision

    Directory of Open Access Journals (Sweden)

    D’Alesio Umberto

    2015-01-01

    Full Text Available The factorization theorem for qT spectra in Drell-Yan processes, boson production and semi-inclusive deep inelastic scattering allows for the determination of the non-perturbative parts of transverse momentum dependent parton distribution functions. Here we discuss the fit of Drell-Yan and Z-production data using the transverse momentum dependent formalism and the resummation of the evolution kernel. We find a good theoretical stability of the results and a final χ2/points ≲ 1. We show how the fixing of the non-perturbative pieces of the evolution can be used to make predictions at present and future colliders.

  19. Landscape Evolution Modelling-LAPSUS

    Energy Technology Data Exchange (ETDEWEB)

    Baartman, J. E. M.; Temme, A. J. A. M.; Schoorl, J. M.; Claessens, L.; Viveen, W.; Gorp, W. van; Veldkamp, A.

    2009-07-01

    Landscape evolution modelling can make the consequences of landscape evolution hypotheses explicit and theoretically allows for their falsification and improvement. ideally, landscape evolution models (LEMs) combine the results of all relevant landscape forming processes into an ever-adapting digital landscape (e.g. DEM). These processes may act on different spatial and temporal scales. LAPSUS is such a LEM. Processes that have in different studies been included in LAPSUS are water erosion and deposition, landslide activity, creep, solidification, weathering, tectonics and tillage. Process descriptions are as simple and generic as possible, ensuring wide applicability. (Author) 25 refs.

  20. Landscape Evolution Modelling-LAPSUS

    International Nuclear Information System (INIS)

    Baartman, J. E. M.; Temme, A. J. A. M.; Schoorl, J. M.; Claessens, L.; Viveen, W.; Gorp, W. van; Veldkamp, A.

    2009-01-01

    Landscape evolution modelling can make the consequences of landscape evolution hypotheses explicit and theoretically allows for their falsification and improvement. ideally, landscape evolution models (LEMs) combine the results of all relevant landscape forming processes into an ever-adapting digital landscape (e.g. DEM). These processes may act on different spatial and temporal scales. LAPSUS is such a LEM. Processes that have in different studies been included in LAPSUS are water erosion and deposition, landslide activity, creep, solidification, weathering, tectonics and tillage. Process descriptions are as simple and generic as possible, ensuring wide applicability. (Author) 25 refs.

  1. Modeling Protein Evolution

    Science.gov (United States)

    Goldstein, Richard; Pollock, David

    The study of biology is fundamentally different from many other scientific pursuits, such as geology or astrophysics. This difference stems from the ubiquitous questions that arise about function and purpose. These are questions concerning why biological objects operate the way they do: what is the function of a polymerase? What is the role of the immune system? No one, aside from the most dedicated anthropist or interventionist theist, would attempt to determine the purpose of the earth's mantle or the function of a binary star. Among the sciences, it is only biology in which the details of what an object does can be said to be part of the reason for its existence. This is because the process of evolution is capable of improving an object to better carry out a function; that is, it adapts an object within the constraints of mechanics and history (i.e., what has come before). Thus, the ultimate basis of these biological questions is the process of evolution; generally, the function of an enzyme, cell type, organ, system, or trait is the thing that it does that contributes to the fitness (i.e., reproductive success) of the organism of which it is a part or characteristic. Our investigations cannot escape the simple fact that all things in biology (including ourselves) are, ultimately, the result of an evolutionary process.

  2. Modelling Geomorphic Systems: Landscape Evolution

    OpenAIRE

    Valters, Declan

    2016-01-01

    Landscape evolution models (LEMs) present the geomorphologist with a means of investigating how landscapes evolve in response to external forcings, such as climate and tectonics, as well as internal process laws. LEMs typically incorporate a range of different geomorphic transport laws integrated in a way that simulates the evolution of a 3D terrain surface forward through time. The strengths of LEMs as research tools lie in their ability to rapidly test many different hypotheses of landscape...

  3. [Mixed states: evolution of classifications].

    Science.gov (United States)

    Pringuey, D; Cherikh, F; Giordana, B; Fakra, E; Dassa, D; Cermolacce, M; Belzeaux, R; Maurel, M; Azorin, J-M

    2013-12-01

    The nosological position of mixed states has followed the course of classifying methods in psychiatry, the steps of the invention of the clinic, progress in the organization of care, including the discoveries of psychopharmacology. The clinical observation of a mixture of symptoms emerging from usually opposite clinical conditions is classical. In the 70s, a syndromic specification fixed the main symptom combinations but that incongruous assortment failed to stabilize the nosological concept. Then stricter criteriology was proposed. To be too restrictive, a consensus operates a dimensional opening that attempts to meet the pragmatic requirements of nosology validating the usefulness of the class system. This alternation between rigor of categorization and return to a more flexible criteriological option reflects the search for the right balance between nosology and diagnosis. The definition of mixed states is best determined by their clinical and prognostic severity, related to the risk of suicide, their lower therapeutic response, the importance of their psychiatric comorbidities, anxiety, emotional lability, alcohol abuse. Trying to compensate for the lack of categorical definitions and better reflecting the clinical field problems, new definitions complement criteriology with dimensional aspects, particularly taking into account temperaments. Copyright © 2013 L’Encéphale. Published by Elsevier Masson SAS.. All rights reserved.

  4. Towards an alternative evolution model.

    Science.gov (United States)

    van Waesberghe, H

    1982-01-01

    Lamarck and Darwin agreed on the inconstancy of species and on the exclusive gradualism of evolution (nature does not jump). Darwinism, revived as neo-Darwinism, was almost generally accepted from about 1930 till 1960. In the sixties the evolutionary importance of selection has been called in question by the neutralists. The traditional conception of the gene is disarranged by recent molecular-biological findings. Owing to the increasing confusion about the concept of genotype, this concept is reconsidered. The idea of the genotype as a cluster of genes is replaced by a cybernetical interpretation of the genotype. As nature does jump, exclusive gradualism is dismissed. Saltatory evolution is a natural phenomenon, provided by a sudden collapse of the thresholds which resist against evolution. The fossil record and the taxonomic system call for a macromutational interpretation. As Lamarck and Darwin overlooked the resistance of evolutionary thresholds, an alternative evolution model is needed, the first to be constructed on a palaeontological and taxonomic basis.

  5. Spatial evolution of quantum mechanical states

    Science.gov (United States)

    Christensen, N. D.; Unger, J. E.; Pinto, S.; Su, Q.; Grobe, R.

    2018-02-01

    The time-dependent Schrödinger equation is solved traditionally as an initial-time value problem, where its solution is obtained by the action of the unitary time-evolution propagator on the quantum state that is known at all spatial locations but only at t = 0. We generalize this approach by examining the spatial evolution from a state that is, by contrast, known at all times t, but only at one specific location. The corresponding spatial-evolution propagator turns out to be pseudo-unitary. In contrast to the real energies that govern the usual (unitary) time evolution, the spatial evolution can therefore require complex phases associated with dynamically relevant solutions that grow exponentially. By introducing a generalized scalar product, for which the spatial generator is Hermitian, one can show that the temporal integral over the probability current density is spatially conserved, in full analogy to the usual norm of the state, which is temporally conserved. As an application of the spatial propagation formalism, we introduce a spatial backtracking technique that permits us to reconstruct any quantum information about an atom from the ionization data measured at a detector outside the interaction region.

  6. CMS computing model evolution

    International Nuclear Information System (INIS)

    Grandi, C; Bonacorsi, D; Colling, D; Fisk, I; Girone, M

    2014-01-01

    The CMS Computing Model was developed and documented in 2004. Since then the model has evolved to be more flexible and to take advantage of new techniques, but many of the original concepts remain and are in active use. In this presentation we will discuss the changes planned for the restart of the LHC program in 2015. We will discuss the changes planning in the use and definition of the computing tiers that were defined with the MONARC project. We will present how we intend to use new services and infrastructure to provide more efficient and transparent access to the data. We will discuss the computing plans to make better use of the computing capacity by scheduling more of the processor nodes, making better use of the disk storage, and more intelligent use of the networking.

  7. Black hole state evolution, final state and Hawking radiation

    International Nuclear Information System (INIS)

    Ahn, D

    2012-01-01

    The effect of a black hole state evolution on the Hawking radiation is studied using the final state boundary condition. It is found that the thermodynamic or statistical mechanical properties of a black hole depend strongly on the unitary evolution operator S, which determines the black hole state evolution. When the operator S is random unitary or pseudo-random unitary, a black hole emits thermal radiation as predicted by Hawking three decades ago. In particular, when the black hole mass of the final state vanishes, Hawking’s original result is retrieved. On the other hand, it is found that the emission of the Hawking radiation could be suppressed when the evolution of a black hole state is determined by the generator of the coherent state. Such a case can occur for some primordial black holes with Planck scale mass formed by primordial density fluctuations through the process of squeezing the zero-point quantum fluctuation of a scalar field. Those primordial black holes can survive until the present time and can contribute to cold dark matter. (paper)

  8. Unitary evolution between pure and mixed states

    International Nuclear Information System (INIS)

    Reznik, B.

    1996-01-01

    We propose an extended quantum mechanical formalism that is based on a wave operator d, which is related to the ordinary density matrix via ρ=dd degree . This formalism allows a (generalized) unitary evolution between pure and mixed states. It also preserves much of the connection between symmetries and conservation laws. The new formalism is illustrated for the case of a two-level system. copyright 1996 The American Physical Society

  9. Evolution of superpositions of quantum states through a level crossing

    International Nuclear Information System (INIS)

    Torosov, B. T.; Vitanov, N. V.

    2011-01-01

    The Landau-Zener-Stueckelberg-Majorana (LZSM) model is widely used for estimating transition probabilities in the presence of crossing energy levels in quantum physics. This model, however, makes the unphysical assumption of an infinitely long constant interaction, which introduces a divergent phase in the propagator. This divergence remains hidden when estimating output probabilities for a single input state insofar as the divergent phase cancels out. In this paper we show that, because of this divergent phase, the LZSM model is inadequate to describe the evolution of pure or mixed superposition states across a level crossing. The LZSM model can be used only if the system is initially in a single state or in a completely mixed superposition state. To this end, we show that the more realistic Demkov-Kunike model, which assumes a hyperbolic-tangent level crossing and a hyperbolic-secant interaction envelope, is free of divergences and is a much more adequate tool for describing the evolution through a level crossing for an arbitrary input state. For multiple crossing energies which are reducible to one or more effective two-state systems (e.g., by the Majorana and Morris-Shore decompositions), similar conclusions apply: the LZSM model does not produce definite values of the populations and the coherences, and one should use the Demkov-Kunike model instead.

  10. Modeling the microstructural evolution during constrained sintering

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Frandsen, Henrik Lund; Tikare, V.

    A numerical model able to simulate solid state constrained sintering of a powder compact is presented. The model couples an existing kinetic Monte Carlo (kMC) model for free sintering with a finite element (FE) method for calculating stresses on a microstructural level. The microstructural response...... to the stress field as well as the FE calculation of the stress field from the microstructural evolution is discussed. The sintering behavior of two powder compacts constrained by a rigid substrate is simulated and compared to free sintering of the same samples. Constrained sintering result in a larger number...

  11. Modeling Evolution of Hydrogen Bonding and Stabilization of Transition States in the Process of Cocaine Hydrolysis Catalyzed by Human Butyrylcholinesterase

    OpenAIRE

    Gao, Daquan; Zhan, Chang-Guo

    2006-01-01

    Molecular dynamics (MD) simulations and quantum mechanical/molecular mechanical (QM/MM) calculations were performed on the prereactive enzyme-substrate complex, transition states, intermediates, and product involved in the process of human butyrylcholinesterase (BChE)-catalyzed hydrolysis of (−)-cocaine. The computational results consistently reveal a unique role of the oxyanion hole (consisting of G116, G117, and A199) in BChE-catalyzed hydrolysis of cocaine, as compared to acetylcholinester...

  12. A simple model for binary star evolution

    International Nuclear Information System (INIS)

    Whyte, C.A.; Eggleton, P.P.

    1985-01-01

    A simple model for calculating the evolution of binary stars is presented. Detailed stellar evolution calculations of stars undergoing mass and energy transfer at various rates are reported and used to identify the dominant physical processes which determine the type of evolution. These detailed calculations are used to calibrate the simple model and a comparison of calculations using the detailed stellar evolution equations and the simple model is made. Results of the evolution of a few binary systems are reported and compared with previously published calculations using normal stellar evolution programs. (author)

  13. Foundations for quantitative microstructural models to track evolution of the metallurgical state during high purity Nb cavity fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Bieler, Thomas R [Michigan State University; Wright, Neil T [Michigan State University; Compton, Chris C [Facility for Rare Isotope Beams

    2014-03-15

    The goal of the Materials Science SRF Cavity Group of Michigan State University and the National Superconducting Cyclotron has been (and continues to be) to understand quantitatively the effects of process history on functional properties. These relationships were assessed via studies on Nb samples and cavity parts, which had various combinations of forming processes, welding, heat treatments, and surface preparation. A primary focus was on large-grain cavity building strategies. Effects of processing operations and exposure to hydrogen on the thermal conductivity has been identified in single and bi-crystal samples, showing that the thermal conductivity can be altered by a factor of 5 depending on process history. Characterization of single crystal tensile samples show a strong effect of crystal orientation on deformation resistance and shape changes. Large grain half cells were examined to characterize defect content and surface damage effects, which provided quantitative information about the depth damage layers from forming.

  14. Modeling evolution of hydrogen bonding and stabilization of transition states in the process of cocaine hydrolysis catalyzed by human butyrylcholinesterase.

    Science.gov (United States)

    Gao, Daquan; Zhan, Chang-Guo

    2006-01-01

    Molecular dynamics (MD) simulations and quantum mechanical/molecular mechanical (QM/MM) calculations were performed on the prereactive enzyme-substrate complex, transition states, intermediates, and product involved in the process of human butyrylcholinesterase (BChE)-catalyzed hydrolysis of (-)-cocaine. The computational results consistently reveal a unique role of the oxyanion hole (consisting of G116, G117, and A199) in BChE-catalyzed hydrolysis of cocaine, compared to acetylcholinesterase (AChE)-catalyzed hydrolysis of acetylcholine. During BChE-catalyzed hydrolysis of cocaine, only G117 has a hydrogen bond with the carbonyl oxygen (O31) of the cocaine benzoyl ester in the prereactive BChE-cocaine complex, and the NH groups of G117 and A199 are hydrogen-bonded with O31 of cocaine in all of the transition states and intermediates. Surprisingly, the NH hydrogen of G116 forms an unexpected hydrogen bond with the carboxyl group of E197 side chain and, therefore, is not available to form a hydrogen bond with O31 of cocaine in the acylation. The NH hydrogen of G116 is only partially available to form a weak hydrogen bond with O31 of cocaine in some structures involved in the deacylation. The change of the estimated hydrogen-bonding energy between the oxyanion hole and O31 of cocaine during the reaction process demonstrates how the protein environment can affect the energy barrier for each step of the BChE-catalyzed hydrolysis of cocaine. These insights concerning the effects of the oxyanion hole on the energy barriers provide valuable clues on how to rationally design BChE mutants with a higher catalytic activity for the hydrolysis of (-)-cocaine. 2005 Wiley-Liss, Inc.

  15. The fast debris evolution model

    Science.gov (United States)

    Lewis, H. G.; Swinerd, G. G.; Newland, R. J.; Saunders, A.

    2009-09-01

    The 'particles-in-a-box' (PIB) model introduced by Talent [Talent, D.L. Analytic model for orbital debris environmental management. J. Spacecraft Rocket, 29 (4), 508-513, 1992.] removed the need for computer-intensive Monte Carlo simulation to predict the gross characteristics of an evolving debris environment. The PIB model was described using a differential equation that allows the stability of the low Earth orbit (LEO) environment to be tested by a straightforward analysis of the equation's coefficients. As part of an ongoing research effort to investigate more efficient approaches to evolutionary modelling and to develop a suite of educational tools, a new PIB model has been developed. The model, entitled Fast Debris Evolution (FADE), employs a first-order differential equation to describe the rate at which new objects ⩾10 cm are added and removed from the environment. Whilst Talent [Talent, D.L. Analytic model for orbital debris environmental management. J. Spacecraft Rocket, 29 (4), 508-513, 1992.] based the collision theory for the PIB approach on collisions between gas particles and adopted specific values for the parameters of the model from a number of references, the form and coefficients of the FADE model equations can be inferred from the outputs of future projections produced by high-fidelity models, such as the DAMAGE model. The FADE model has been implemented as a client-side, web-based service using JavaScript embedded within a HTML document. Due to the simple nature of the algorithm, FADE can deliver the results of future projections immediately in a graphical format, with complete user-control over key simulation parameters. Historical and future projections for the ⩾10 cm LEO debris environment under a variety of different scenarios are possible, including business as usual, no future launches, post-mission disposal and remediation. A selection of results is presented with comparisons with predictions made using the DAMAGE environment model

  16. Time evolution of tokamak states with flow

    International Nuclear Information System (INIS)

    Kerner, W.; Weitzner, H.

    1985-12-01

    The general dissipative Braginskii single-fluid model is applied to simulate tokamak transport. An expansion with respect to epsilon = (ω/sub i/tau/sub i/) -1 , the factor by which perpendicular and parallel transport coefficients differ, yields a numerically tractable scheme. The resulting 1-1/2 D procedure requires computation of 2D toroidal equilibria with flow together with the solution of a system of ordinary 1D flux-averaged equations for the time evolution of the profiles. 13 refs

  17. State-dependent cognition and its relevance to cultural evolution.

    Science.gov (United States)

    Nettle, Daniel

    2018-02-05

    Individuals cope with their worlds by using information. In humans in particular, an important potential source of information is cultural tradition. Evolutionary models have examined when it is advantageous to use cultural information, and psychological studies have examined the cognitive biases and priorities that may transform cultural traditions over time. However, these studies have not generally incorporated the idea that individuals vary in state. I argue that variation in state is likely to influence the relative payoffs of using cultural information versus gathering personal information; and also that people in different states will have different cognitive biases and priorities, leading them to transform cultural information in different ways. I explore hunger as one example of state variable likely to have consequences for cultural evolution. Variation in state has the potential to explain why cultural traditions and dynamics are so variable between individuals and populations. It offers evolutionarily-grounded links between the ecology in which individuals live, individual-level cognitive processes, and patterns of culture. However, incorporating heterogeneity of state also makes the modelling of cultural evolution more complex, particularly if the distribution of states is itself influenced by the distribution of cultural beliefs and practices. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. My Life with State Space Models

    DEFF Research Database (Denmark)

    Lundbye-Christensen, Søren

    2007-01-01

    . The conceptual idea behind the state space model is that the evolution over time in the object we are observing and the measurement process itself are modelled separately. My very first serious analysis of a data set was done using a state space model, and since then I seem to have been "haunted" by state space...

  19. Pore Pressure Evolution in Shallow Subduction Earthquake Sequences and Effects on Aseismic Slip Transients -- Numerical Modeling With Rate and State Friction

    Science.gov (United States)

    Liu, Y.; Rice, J. R.

    2005-12-01

    In 3D modeling of long tectonic loading and earthquake sequences on a shallow subduction fault [Liu and Rice, 2005], with depth-variable rate and state friction properties, we found that aseismic transient slip episodes emerge spontaneously with only a simplified representation of effects of metamorphic fluid release. That involved assumption of a constant in time but uniformly low effective normal stress in the downdip region. As suggested by observations in several major subduction zones [Obara, 2002; Rogers and Dragert, 2003; Kodaira et al, 2004], the presence of fluids, possibly released from dehydration reactions beneath the seismogenic zone, and their pressurization within the fault zone may play an important role in causing aseismic transients and associated non-volcanic tremors. To investigate the effects of fluids in the subduction zone, particularly on the generation of aseismic transients and their various features, we develop a more complete physical description of the pore pressure evolution (specifically, pore pressure increase due to supply from dehydration reactions and shear heating, decrease due to transport and dilatancy during slip), and incorporate that into the rate and state based 3D modeling. We first incorporated two important factors, dilatancy and shear heating, following Segall and Rice [1995, 2004] and Taylor [1998]. In the 2D simulations (slip varies with depth only), a dilatancy-stabilizing effect is seen which slows down the seismic rupture front and can prevent rapid slip from extending all the way to the trench, similarly to Taylor [1998]. Shear heating increases the pore pressure, and results in faster coseismic rupture propagation and larger final slips. In the 3D simulations, dilatancy also stabilizes the along-strike rupture propagation of both seismic and aseismic slips. That is, aseismic slip transients migrate along the strike faster with a shorter Tp (the characteristic time for pore pressure in the fault core to re

  20. Optimal evolution models for quantum tomography

    International Nuclear Information System (INIS)

    Czerwiński, Artur

    2016-01-01

    The research presented in this article concerns the stroboscopic approach to quantum tomography, which is an area of science where quantum physics and linear algebra overlap. In this article we introduce the algebraic structure of the parametric-dependent quantum channels for 2-level and 3-level systems such that the generator of evolution corresponding with the Kraus operators has no degenerate eigenvalues. In such cases the index of cyclicity of the generator is equal to 1, which physically means that there exists one observable the measurement of which performed a sufficient number of times at distinct instants provides enough data to reconstruct the initial density matrix and, consequently, the trajectory of the state. The necessary conditions for the parameters and relations between them are introduced. The results presented in this paper seem to have considerable potential applications in experiments due to the fact that one can perform quantum tomography by conducting only one kind of measurement. Therefore, the analyzed evolution models can be considered optimal in the context of quantum tomography. Finally, we introduce some remarks concerning optimal evolution models in the case of n-dimensional Hilbert space. (paper)

  1. Quantitative interface models for simulating microstructure evolution

    International Nuclear Information System (INIS)

    Zhu, J.Z.; Wang, T.; Zhou, S.H.; Liu, Z.K.; Chen, L.Q.

    2004-01-01

    To quantitatively simulate microstructural evolution in real systems, we investigated three different interface models: a sharp-interface model implemented by the software DICTRA and two diffuse-interface models which use either physical order parameters or artificial order parameters. A particular example is considered, the diffusion-controlled growth of a γ ' precipitate in a supersaturated γ matrix in Ni-Al binary alloys. All three models use the thermodynamic and kinetic parameters from the same databases. The temporal evolution profiles of composition from different models are shown to agree with each other. The focus is on examining the advantages and disadvantages of each model as applied to microstructure evolution in alloys

  2. Speed of quantum evolution of entangled two qubits states: Local vs. global evolution

    International Nuclear Information System (INIS)

    Curilef, S; Zander, C; Plastino, A R

    2008-01-01

    There is a lower bound for the 'speed' of quantum evolution as measured by the time needed to reach an orthogonal state. We show that, for two-qubits systems, states saturating the quantum speed limit tend to exhibit a small amount of local evolution, as measured by the fidelity between the initial and final single qubit states after the time τ required by the composite system to reach an orthogonal state. Consequently, a trade-off between the speed of global evolution and the amount of local evolution seems to be at work.

  3. Spin Glass Models of Syntax and Language Evolution

    OpenAIRE

    Siva, Karthik; Tao, Jim; Marcolli, Matilde

    2015-01-01

    Using the SSWL database of syntactic parameters of world languages, and the MIT Media Lab data on language interactions, we construct a spin glass model of language evolution. We treat binary syntactic parameters as spin states, with languages as vertices of a graph, and assigned interaction energies along the edges. We study a rough model of syntax evolution, under the assumption that a strong interaction energy tends to cause parameters to align, as in the case of ferromagnetic materials. W...

  4. Biodiversity and models of evolution

    Directory of Open Access Journals (Sweden)

    S. L. Podvalny

    2016-01-01

    Full Text Available Summary. The paper discusses the evolutionary impact of biodiversity, the backbone of noosphere, which status has been fixed by a UN convention. The examples and role of such diversity are considered the various levels of life arrangement. On the level of standalone organisms, the diversity in question manifests itself in the differentiation and separation of the key physiologic functions which significantly broaden the eco-niche for the species with the consummate type of such separation. However, the organismic level of biodiversity does not work for building any developmental models since the starting point of genetic inheritance and variability processes emerges on the minimum structural unit of the living world only, i.e. the population. It is noted that the sufficient gene pool for species development may accumulate in fairly large populations only, where the general rate of mutation does not yield to the rate of ambient variations. The paper shows that the known formal models of species development based on the Fisher theorem about the impact of genodispersion on species adjustment are not in keeping with the actual existence of the species due to the conventionally finite and steady number of genotypes within a population. On the ecosystem level of life arrangement, the key role pertains to the taxonomic diversity supporting the continuous food chain in the system against any adverse developmental conditions of certain taxons. Also, the progressive evolution of an ecosystem is largely stabilized by its multilayer hierarchic structure and the closed circle of matter and energy. The developmental system models based on the Lotka-Volterra equations describing the interaction of the open-loop ecosystem elements only insufficiently represent the position of biodiversity in the evolutionary processes. The paper lays down the requirements to such models which take into account the mass balance within a system; its trophic structure; the

  5. Evolution of the ICESIM model

    International Nuclear Information System (INIS)

    Carson, R.W.; Groeneveld, J.L.

    1997-01-01

    A computer model named ICESIM was developed by Acres International in 1973 to study river ice problems associated with the construction of the Limestone Hydroelectric Generating Station on the Nelson River. The program could numerically simulate the processes of river ice formation under steady state conditions of flow. The program has evolved over two decades and has been used as a design and analytical tool for several river ice problems. One of the shortcomings of the model was its inability to consider varying river flows during a simulation. The model has recently been restructured into a new version called ICEDYN which uses a hydrodynamic module to compute river hydraulics. The ICEDYN program uses the same approach as ICESIM, but river hydraulics, which are affected by changes in inflow, and the accumulation of ice, are computed through a hydrodynamic solution of the St. Venant Equations. The ICEDYN model requires an extensive data set to describe the particular river reach being simulated. It has been tested on the Nelson River in northern Manitoba to see whether the numerical methods in the model can successfully represent field conditions. Results were encouraging but additional refinement is still needed. 7 refs., 1 tab., 7 figs

  6. SYNTHETIC AGB EVOLUTION .1. A NEW MODEL

    NARCIS (Netherlands)

    GROENEWEGEN, MAT; DEJONG, T

    We have constructed a model to calculate in a synthetic way the evolution of stars on the asymptotic giant branch (AGB). The evolution is started at the first thermal pulse (TP) and is terminated when the envelope mass has been lost due to mass loss or when the core mass reaches the Chandrasekhar

  7. Geometric phases for mixed states during cyclic evolutions

    International Nuclear Information System (INIS)

    Fu Libin; Chen Jingling

    2004-01-01

    The geometric phases of cyclic evolutions for mixed states are discussed in the framework of unitary evolution. A canonical 1-form is defined whose line integral gives the geometric phase, which is gauge invariant. It reduces to the Aharonov and Anandan phase in the pure state case. Our definition is consistent with the phase shift in the proposed experiment (Sjoeqvist et al 2000 Phys. Rev. Lett. 85 2845) for a cyclic evolution if the unitary transformation satisfies the parallel transport condition. A comprehensive geometric interpretation is also given. It shows that the geometric phases for mixed states share the same geometric sense with the pure states

  8. The effects of magmatic redistribution of heat producing elements on the lunar mantle evolution inferred from numerical models that start from various initial states

    Science.gov (United States)

    Ogawa, Masaki

    2018-02-01

    To discuss how redistribution of heat producing elements (HPEs) by magmatism affects the lunar mantle evolution depending on the initial condition, I present two-dimensional numerical models of magmatism in convecting mantle internally heated by incompatible HPEs. Mantle convection occurs beneath a stagnant lithosphere that inhibits recycling of the HPE-enriched crustal materials to the mantle. Magmatism is modeled by a permeable flow of magma generated by decompression melting through matrix. Migrating magma transports heat, mass, and HPEs. When the deep mantle is initially hot with the temperature TD around 1800 K at its base, magmatism starts from the beginning of the calculated history to extract HPEs from the mantle. The mantle is monotonously cooled, and magmatism ceases within 2 Gyr, accordingly. When the deep mantle is initially colder with TD around 1100 K, HPEs stay in the deep mantle for a longer time to let the planet be first heated up and then cooled only slightly. If, in addition, there is an HPE-enriched domain in the shallow mantle at the beginning of the calculation, magma continues ascending to the surface through the domain for more than 3 Gyr. The low TD models fit in with the thermal and magmatic history of the Moon inferred from spacecraft observations, although it is not clear if the models are consistent with the current understanding of the origin of the Moon and its magnetic field. Redistribution of HPEs by magmatism is a crucial factor that must be taken into account in future studies of the evolution of the Moon.

  9. Automata network models of galaxy evolution

    Science.gov (United States)

    Chappell, David; Scalo, John

    1993-01-01

    Two ideas appear frequently in theories of star formation and galaxy evolution: (1) star formation is nonlocally excitatory, stimulating star formation in neighboring regions by propagation of a dense fragmenting shell or the compression of preexisting clouds; and (2) star formation is nonlocally inhibitory, making H2 regions and explosions which can create low-density and/or high temperature regions and increase the macroscopic velocity dispersion of the cloudy gas. Since it is not possible, given the present state of hydrodynamic modeling, to estimate whether one of these effects greatly dominates the other, it is of interest to investigate the predicted spatial pattern of star formation and its temporal behavior in simple models which incorporate both effects in a controlled manner. The present work presents preliminary results of such a study which is based on lattice galaxy models with various types of nonlocal inhibitory and excitatory couplings of the local SFR to the gas density, temperature, and velocity field meant to model a number of theoretical suggestions.

  10. Time evolution of gibbs states for an anharmonic lattice

    Energy Technology Data Exchange (ETDEWEB)

    Marchioro, C; Pellegrinotti, A; Suhov, Y [Camerino Univ. (Italy). Istituto di Matematica; Pulvirenti, M [L' Aquila Univ. (Italy). Istituto di Matematica; Rome Univ. (Italy). Istituto di Matematica)

    1979-01-01

    In this paper we study the time evolution of a regular class of states of an infinite classical system of anharmonic oscillators. The conditional probabilities are investigated and an explicit form for these is given.

  11. Time evolution of gibbs states for an anharmonic lattice

    International Nuclear Information System (INIS)

    Marchioro, C.; Pellegrinotti, A.; Suhov, Y.; Pulvirenti, M.; Rome Univ.

    1979-01-01

    In this paper we study the time evolution of a regular class of states of an infinite classical system of anharmonic oscillators. The conditional probabilities are investigated and an explicit form for these is given. (orig.) [de

  12. Modeling volatility using state space models.

    Science.gov (United States)

    Timmer, J; Weigend, A S

    1997-08-01

    In time series problems, noise can be divided into two categories: dynamic noise which drives the process, and observational noise which is added in the measurement process, but does not influence future values of the system. In this framework, we show that empirical volatilities (the squared relative returns of prices) exhibit a significant amount of observational noise. To model and predict their time evolution adequately, we estimate state space models that explicitly include observational noise. We obtain relaxation times for shocks in the logarithm of volatility ranging from three weeks (for foreign exchange) to three to five months (for stock indices). In most cases, a two-dimensional hidden state is required to yield residuals that are consistent with white noise. We compare these results with ordinary autoregressive models (without a hidden state) and find that autoregressive models underestimate the relaxation times by about two orders of magnitude since they do not distinguish between observational and dynamic noise. This new interpretation of the dynamics of volatility in terms of relaxators in a state space model carries over to stochastic volatility models and to GARCH models, and is useful for several problems in finance, including risk management and the pricing of derivative securities. Data sets used: Olsen & Associates high frequency DEM/USD foreign exchange rates (8 years). Nikkei 225 index (40 years). Dow Jones Industrial Average (25 years).

  13. Modelling the evolution and diversity of cumulative culture

    Science.gov (United States)

    Enquist, Magnus; Ghirlanda, Stefano; Eriksson, Kimmo

    2011-01-01

    Previous work on mathematical models of cultural evolution has mainly focused on the diffusion of simple cultural elements. However, a characteristic feature of human cultural evolution is the seemingly limitless appearance of new and increasingly complex cultural elements. Here, we develop a general modelling framework to study such cumulative processes, in which we assume that the appearance and disappearance of cultural elements are stochastic events that depend on the current state of culture. Five scenarios are explored: evolution of independent cultural elements, stepwise modification of elements, differentiation or combination of elements and systems of cultural elements. As one application of our framework, we study the evolution of cultural diversity (in time as well as between groups). PMID:21199845

  14. Evolutive Masing model, cycling plasticity, ageing and memory effects

    International Nuclear Information System (INIS)

    Sidoroff, F.

    1987-01-01

    Many models are proposed for the mechanical description of the cyclic behaviour of metals and used for structure analysis under cyclic loading. The evolutive Masing model has been proposed (Fougeres, Sidoroff, Vincent and Waille 1985) to combine - the accuracy of hereditary models for the description of hysteresis on each cycle, - the versatility of internal variables for the state description and evolution, - a sufficient microstructural basis to make the interaction easier with microstructural investigations. The purpose of the present work is to discuss this model and to compare different evolution assumptions with respect to some memory effects (cyclic hardening and softening, multilevel tests, ageing). Attention is limited to uniaxial, rate independent elasto-plastic behaviour. (orig./GL)

  15. Evolutive masing model, cyclic plasticity, ageing and memory effects

    International Nuclear Information System (INIS)

    Sidoroff, F.

    1987-01-01

    Many models are proposed for the mechanical description of the cyclic behaviour of metals and used for structure analysis under cyclic loading. Such a model must include two basic features: Dissipative behaviour on each cycle (hysteresis loop); evolution of this behaviour during the material's life (cyclic hardening or softening, aging,...). However, if both aspects are present in most existing models, the balance between them may be quite different. Many metallurgical investigations have been performed about the microstructure and its evolution during cyclic loading, and it is desirable to introduce these informations in phenomenological models. The evolutive Masing model has been proposed to combine: the accuracy of hereditary models for the description of hysteresis on each cycle, the versatility of internal variables for the state description and evolution, a sufficient microstructural basis to make the interaction easier with microstructural investigations. The purpose of the present work is to discuss this model and to compare different evolution assumptions with respect to some memory effects (cyclic hardening and softening, multilevel tests, aging). Attention is limited to uniaxial, rate independent elasto-plastic behaviour

  16. A distributed snow-evolution modeling system (SnowModel)

    Science.gov (United States)

    Glen E. Liston; Kelly. Elder

    2006-01-01

    SnowModel is a spatially distributed snow-evolution modeling system designed for application in landscapes, climates, and conditions where snow occurs. It is an aggregation of four submodels: MicroMet defines meteorological forcing conditions, EnBal calculates surface energy exchanges, SnowPack simulates snow depth and water-equivalent evolution, and SnowTran-3D...

  17. Modelling offshore sand wave evolution

    NARCIS (Netherlands)

    Nemeth, Attila; Hulscher, Suzanne J.M.H.; van Damme, Rudolf M.J.

    2007-01-01

    We present a two-dimensional vertical (2DV) flow and morphological numerical model describing the behaviour of offshore sand waves. The model contains the 2DV shallow water equations, with a free water surface and a general bed load formula. The water movement is coupled to the sediment transport

  18. Shallow nitrogen ion implantation: Evolution of chemical state and defect structure in titanium

    Energy Technology Data Exchange (ETDEWEB)

    Manojkumar, P.A., E-mail: manoj@igcar.gov.in [Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Chirayath, V.A.; Balamurugan, A.K.; Krishna, Nanda Gopala; Ilango, S.; Kamruddin, M.; Amarendra, G.; Tyagi, A.K. [Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Raj, Baldev [National Institute of Advanced Studies, Bangalore 560 012 (India)

    2016-09-15

    Highlights: • Low energy nitrogen ion implantation in titanium was studied. • Chemical and defect states were analyzed using SIMS, XPS and PAS. • SIMS and depth resolved XPS data showed good agreement. • Depth resolved defect and chemical states information were revealed. • Formation of 3 layers of defect states proposed to fit PAS results. - Abstract: Evolution of chemical states and defect structure in titanium during low energy nitrogen ion implantation by Plasma Immersion Ion Implantation (PIII) process is studied. The underlying process of chemical state evolution is investigated using secondary ion mass spectrometry and X-ray photoelectron spectroscopy. The implantation induced defect structure evolution as a function of dose is elucidated using variable energy positron annihilation Doppler broadening spectroscopy (PAS) and the results were corroborated with chemical state. Formation of 3 layers of defect state was modeled to fit PAS results.

  19. QSO evolution in the interaction model

    International Nuclear Information System (INIS)

    De Robertis, M.

    1985-01-01

    QSO evolution is investigated according to the interaction hypothesis described most recently by Stockton (1982), in which activity results from an interaction between two galaxies resulting in the transfer of gas onto a supermassive black hole (SBH) at the center of at least one participant. Explicit models presented here for interactions in cluster environments show that a peak QSO population can be formed in this way at zroughly-equal2--3, with little activity prior to this epoch. Calculated space densities match those inferred from observations for this epoch. Substantial density evolution is expected in such models, since, after virialization, conditions in the cores of rich clusters lead to the depletion of gas-rich systems through ram-pressure stripping. Density evolution parameters of 6--12 are easily accounted for. At smaller redshifts, however, QSOs should be found primarily in poor clusters or groups. Probability estimates provided by this model are consistent with local estimates for the observed number of QSOs per interaction. Significant luminosity-dependent evolution might also be expected in these models. It is suggested that the mean SBH mass increases with lookback time, leading to a statistical brightening with redshift. Undoubtedly, both forms of evolution contribute to the overall QSO luminosity function

  20. Shaping asteroid models using genetic evolution (SAGE)

    Science.gov (United States)

    Bartczak, P.; Dudziński, G.

    2018-02-01

    In this work, we present SAGE (shaping asteroid models using genetic evolution), an asteroid modelling algorithm based solely on photometric lightcurve data. It produces non-convex shapes, orientations of the rotation axes and rotational periods of asteroids. The main concept behind a genetic evolution algorithm is to produce random populations of shapes and spin-axis orientations by mutating a seed shape and iterating the process until it converges to a stable global minimum. We tested SAGE on five artificial shapes. We also modelled asteroids 433 Eros and 9 Metis, since ground truth observations for them exist, allowing us to validate the models. We compared the derived shape of Eros with the NEAR Shoemaker model and that of Metis with adaptive optics and stellar occultation observations since other models from various inversion methods were available for Metis.

  1. Evolution: Its Treatment in K-12 State Science Curriculum Standards

    Science.gov (United States)

    Lerner, L. S.

    2001-12-01

    State standards are the basis upon which states and local schools build curricula. Usually taking the form of lists of what students are expected to learn at specified grades or clusters of grades, they influence statewide examinations, textbooks, teacher education and credentialing, and other areas in which states typically exercise control over local curriculum development. State science standards vary very widely in overall quality.1,2 This is especially true in their treatment of evolution, both in the life sciences and to a somewhat lesser extent in geology and astronomy. Not surprisingly, a detailed evaluation of the treatment of evolution in state science standards3 has evoked considerably more public interest than the preceding studies of overall quality. We here consider the following questions: What constitutes a good treatment of evolution in science standards and how does one evaluate the standards? Which states have done well, and which less well? What nonscientific influences have been brought to bear on standards, for what reasons, and by whom? What strategies have been used to obscure or distort the role of evolution as the central organizing principle of the historical sciences? What are the effects of such distortions on students' overall understanding of science? What can the scientific community do to assure the publication of good science standards and to counteract attacks on good science teaching? 1. Lerner, L. S., State Science Standards: An Appraisal of Science Standards in 36 States, The Thomas B. Fordham Foundation, Washington, D.C., March 1998. 2. Lerner, L. S. et al ., The State of State Standards 2000, ibid., January 2000. 3. Lerner, L. S., Good Science, Bad Science: Teaching Evolution In the States, ibid., September 2000.

  2. A model for evolution and extinction

    OpenAIRE

    Roberts, Bruce W.; Newman, M. E. J.

    1995-01-01

    We present a model for evolution and extinction in large ecosystems. The model incorporates the effects of interactions between species and the influences of abiotic environmental factors. We study the properties of the model by approximate analytic solution and also by numerical simulation, and use it to make predictions about the distribution of extinctions and species lifetimes that we would expect to see in real ecosystems. It should be possible to test these predictions against the fossi...

  3. Evolution from pure states into mixed states in de Sitter space

    International Nuclear Information System (INIS)

    Sakagami, Masa-aki.

    1987-03-01

    An attempt is made to clarify realization of a classical distribution from quantum fluctuations of the order parameter in the inflationary universe. We discuss destruction of quantum coherence associated with a state of the order parameter in models where it interacts with the environment. For that purpose, the time evolution of the reduced density matrix ρ tilde, which is obtained by coarse-graining of the environment, is investigated. It is shown that off-diagonal elements of ρ tilde decrease as the phase transition proceeds. (author)

  4. The thermal evolution of universe: standard model

    International Nuclear Information System (INIS)

    Nascimento, L.C.S. do.

    1975-08-01

    A description of the dynamical evolution of the Universe following a model based on the theory of General Relativity is made. The model admits the Cosmological principle,the principle of Equivalence and the Robertson-Walker metric (of which an original derivation is presented). In this model, the universe is considered as a perfect fluid, ideal and symmetric relatively to the number of particles and antiparticles. The thermodynamic relations deriving from these hypothesis are derived, and from them the several eras of the thermal evolution of the universe are established. Finally, the problems arising from certain specific predictions of the model are studied, and the predictions of the abundances of the elements according to nucleosynthesis and the actual behavior of the universe are analysed in detail. (author) [pt

  5. Modeling of microstructural evolution under irradiation

    International Nuclear Information System (INIS)

    Odette, G.R.

    1979-01-01

    Microstructural evolution under irradiation is an extremely complex phenomenon involving numerous interacting mechanisms which alter both the microstructure and microchemistry of structural alloys. Predictive procedures which correlate primary irradiation and material variables to microstructural response are needed to extrapolate from the imperfect data base, which will be available, to fusion reactor conditions. Clearly, a marriage between models and experiments is needed. Specific steps to achieving such a marriage in the form of composite correlation model analysis are outlined and some preliminary results presented. The strongly correlated nature of microstructural evolution is emphasized and it is suggested that rate theory models, resting on the principle of material balances and focusing on coupled point defect-microchemical segregation processes, may be a practical approach to correlation model development. (orig.)

  6. Evolution of the authoritarian 'atom state'

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    Robert Jungk's book 'The Atom State' forms the basis for this article, which begins with a general discussion and criticism of such government sponsored reports as the Rasmussen report. The utilisation by the nuclear industry of modern PR methods is also criticised. Specifically, Bruno Kreisky and the Austrian Minister of the Economy, Herta Firnberg, are accused of attempting, through a secret project, to mislead the public and exercise unethical influence. It is maintained that the existence of a nuclear industry will necessitate control measures which lead to a totalitarian regime. (JIW)

  7. Fault Wear by Damage Evolution During Steady-State Slip

    Science.gov (United States)

    Lyakhovsky, Vladimir; Sagy, Amir; Boneh, Yuval; Reches, Ze'ev

    2014-11-01

    Slip along faults generates wear products such as gouge layers and cataclasite zones that range in thickness from sub-millimeter to tens of meters. The properties of these zones apparently control fault strength and slip stability. Here we present a new model of wear in a three-body configuration that utilizes the damage rheology approach and considers the process as a microfracturing or damage front propagating from the gouge zone into the solid rock. The derivations for steady-state conditions lead to a scaling relation for the damage front velocity considered as the wear-rate. The model predicts that the wear-rate is a function of the shear-stress and may vanish when the shear-stress drops below the microfracturing strength of the fault host rock. The simulated results successfully fit the measured friction and wear during shear experiments along faults made of carbonate and tonalite. The model is also valid for relatively large confining pressures, small damage-induced change of the bulk modulus and significant degradation of the shear modulus, which are assumed for seismogenic zones of earthquake faults. The presented formulation indicates that wear dynamics in brittle materials in general and in natural faults in particular can be understood by the concept of a "propagating damage front" and the evolution of a third-body layer.

  8. Marco histórico y estado del arte de los modelos de evolución del paisaje y de erosión Historical framework and state of art of landscape evolution and erosion models

    Directory of Open Access Journals (Sweden)

    Juan José Montoya Monsalve

    2009-07-01

    Full Text Available Se presenta un análisis del marco histórico de modelos de evolución del paisaje y de erosión, además se expone el estado del arte de cuyo análisis se derivan los aspectos fundamentales que deben ser tenidos en cuenta en la formulación de un modelo de erosión a escala de cuenca. Se introduce el tema con un breve recuento de la evolución del conocimiento de modelos geomorfológicos, los cuales constituyen el marco general de los modelos de erosión. De dicho análisis surgen las preguntas básicas que debe abordar un modelo de erosión. Posteriormente se efectúa un análisis del desarrollo histórico de modelos de erosión, se reseñan las características principales de los modelos de erosión actuales y se enumeran las potencialidades y limitaciones de estos. Este artículo corresponde a una revisión bibliográfica tendente a la definición del marco teórico del proyecto de investigación titulado "Desarrollo de un modelo conceptual de producción, transporte y depósito de sedimentos".This articles presents an analysis of the historical framework of landscape evolution models, specifically erosion models: it also refers to the current state of the art from which critical analysis derive the fundamental aspects which should be taken into account in the formulation of an erosion model in catchment scale. The theme is introduced with a brief review of the evolution of knowledge of landscape evolution models, which provide the overall framework of erosion models. From this analysis, basic questions to be addressed by an erosion model arise. Later, analysis of the historical development of erosion models is made; It also summarizes the main characteristics of the current erosion models and lists potentialities and limitations of erosion models. This paper corresponds to a literature review aimed at defining the theoretical framework of a research project entitled "Development of an Erosion, Transport and Sedimentation Conceptual Model."

  9. Entanglement Evolution of Three-Qubit States under Local Decoherence

    International Nuclear Information System (INIS)

    Ma Xiaosan; Liu Gaosheng; Wang Anmin

    2010-01-01

    By using negativity as entanglement measure, we have investigated the effect of local decoherence from a non-Markovian environment on the time evolution of entanglement of three-qubit states including the GHZ state, the W state, and the Werner state. From the results, we find that the entanglement dynamics depends not only on the coupling strengths but also on the specific states of concern. Specifically, the entanglement takes different behaviors under weak or strong coupling and it varies with the quantum states under study. The entanglement of the GHZ state and the Werner state can be destroyed completely by the local decoherence, while the entanglement of the W state can survive through the local decoherence partially. (general)

  10. Models of multiquark states

    International Nuclear Information System (INIS)

    Lipkin, H.J.

    1986-01-01

    The success of simple constituent quark models in single-hardon physics and their failure in multiquark physics is discussed, emphasizing the relation between meson and baryon spectra, hidden color and the color matrix, breakup decay modes, coupled channels, and hadron-hadron interactions via flipping and tunneling of flux tubes. Model-independent predictions for possible multiquark bound states are considered and the most promising candidates suggested. A quark approach to baryon-baryon interactions is discussed

  11. Corporatism In Western Europe: Current State And Prospects For Evolution

    Directory of Open Access Journals (Sweden)

    Р. Ja. Feldman

    2018-01-01

    Full Text Available The article conducts a political analysis of the Western European institutions of corporatism. The main task of the author is the study of the policy of harmonizing the interests of labor and capital (trade unions and employers’ associations, which is implemented in countries such as the UK, Germany, France, Italy, Norway, Sweden, Denmark etc. Dynamics of political processes unfolding in the space of Western Europe, suggests that the mechanisms of articulation and political representation of social and labour interests have significantly transformed over the past 30 years. The use of institutional and systemic approaches along with the empirical methods, leads to the conclusion that the most developed European countries are moving from the classical model of corporatism to a more pluralistic forms of interaction between the state, labour and capital. Social partnership as an instrument of collective bargaining between employees and employers is displaced from the political sphere to the sectoral and organizational levels. The typical institutions of democratic corporatism (tripartite commissions, socio-economic councils, etc., who played a crucial role in rebuilding post-war Europe, become rudimentary organs of the national political systems. In addition, there is a tendency to weaken the political influence of trade unions, who successfully struggled for the satisfaction of collective demands of workers in the beginning of XX century. Large multinational companies prefer to influence the political decision-making centers autonomously, ignoring the associative membership in the guild organizations. As a consequence, corporatist bargaining is being replaced by direct and indirect lobbying, Government Relations and election fundraising. When accounting for identified trends, the author presents a hypothesis that the evolution of corporatism in Western Europe will lead to its gradual degeneration. Taking into account the identified trends, the

  12. Long range anti-ferromagnetic spin model for prebiotic evolution

    International Nuclear Information System (INIS)

    Nokura, Kazuo

    2003-01-01

    I propose and discuss a fitness function for one-dimensional binary monomer sequences of macromolecules for prebiotic evolution. The fitness function is defined by the free energy of polymers in the high temperature random coil phase. With repulsive interactions among the same kind of monomers, the free energy in the high temperature limit becomes the energy function of the one-dimensional long range anti-ferromagnetic spin model, which is shown to have a dynamical phase transition and glassy states

  13. Modeling aeolian dune and dune field evolution

    Science.gov (United States)

    Diniega, Serina

    Aeolian sand dune morphologies and sizes are strongly connected to the environmental context and physical processes active since dune formation. As such, the patterns and measurable features found within dunes and dune fields can be interpreted as records of environmental conditions. Using mathematical models of dune and dune field evolution, it should be possible to quantitatively predict dune field dynamics from current conditions or to determine past field conditions based on present-day observations. In this dissertation, we focus on the construction and quantitative analysis of a continuum dune evolution model. We then apply this model towards interpretation of the formative history of terrestrial and martian dunes and dune fields. Our first aim is to identify the controls for the characteristic lengthscales seen in patterned dune fields. Variations in sand flux, binary dune interactions, and topography are evaluated with respect to evolution of individual dunes. Through the use of both quantitative and qualitative multiscale models, these results are then extended to determine the role such processes may play in (de)stabilization of the dune field. We find that sand flux variations and topography generally destabilize dune fields, while dune collisions can yield more similarly-sized dunes. We construct and apply a phenomenological macroscale dune evolution model to then quantitatively demonstrate how dune collisions cause a dune field to evolve into a set of uniformly-sized dunes. Our second goal is to investigate the influence of reversing winds and polar processes in relation to dune slope and morphology. Using numerical experiments, we investigate possible causes of distinctive morphologies seen in Antarctic and martian polar dunes. Finally, we discuss possible model extensions and needed observations that will enable the inclusion of more realistic physical environments in the dune and dune field evolution models. By elucidating the qualitative and

  14. LAPSUS: soil erosion - landscape evolution model

    Science.gov (United States)

    van Gorp, Wouter; Temme, Arnaud; Schoorl, Jeroen

    2015-04-01

    LAPSUS is a soil erosion - landscape evolution model which is capable of simulating landscape evolution of a gridded DEM by using multiple water, mass movement and human driven processes on multiple temporal and spatial scales. It is able to deal with a variety of human landscape interventions such as landuse management and tillage and it can model their interactions with natural processes. The complex spatially explicit feedbacks the model simulates demonstrate the importance of spatial interaction of human activity and erosion deposition patterns. In addition LAPSUS can model shallow landsliding, slope collapse, creep, solifluction, biological and frost weathering, fluvial behaviour. Furthermore, an algorithm to deal with natural depressions has been added and event-based modelling with an improved infiltration description and dust deposition has been pursued. LAPSUS has been used for case studies in many parts of the world and is continuously developing and expanding. it is now available for third-party and educational use. It has a comprehensive user interface and it is accompanied by a manual and exercises. The LAPSUS model is highly suitable to quantify and understand catchment-scale erosion processes. More information and a download link is available on www.lapsusmodel.nl.

  15. Abundance gradients in disc galaxies and chemical evolution models

    International Nuclear Information System (INIS)

    Diaz, A.I.

    1989-01-01

    The present state of abundance gradients and chemical evolution models of spiral galaxies is reviewed. An up to date compilation of abundance data in the literature concerning HII regions over galactic discs is presented. From these data Oxygen and Nitrogen radial gradients are computed. The slope of the Oxygen gradient is shown to have a break at a radius between 1.5 and 1.75 times the value of the effective radius of the disc, i.e. the radius containing half of the light of the disc. The gradient is steeper in the central parts of the disc and becomes flatter in the outer parts. N/O gradients are shown to be rather different from galaxy to galaxy and only a weak trend of N/O with O/H is found. The existing chemical evolution models for spiral galaxies are reviewed with special emphasis in the interpretation of numerical models having a large number of parameters. (author)

  16. Differential Evolution algorithm applied to FSW model calibration

    Science.gov (United States)

    Idagawa, H. S.; Santos, T. F. A.; Ramirez, A. J.

    2014-03-01

    Friction Stir Welding (FSW) is a solid state welding process that can be modelled using a Computational Fluid Dynamics (CFD) approach. These models use adjustable parameters to control the heat transfer and the heat input to the weld. These parameters are used to calibrate the model and they are generally determined using the conventional trial and error approach. Since this method is not very efficient, we used the Differential Evolution (DE) algorithm to successfully determine these parameters. In order to improve the success rate and to reduce the computational cost of the method, this work studied different characteristics of the DE algorithm, such as the evolution strategy, the objective function, the mutation scaling factor and the crossover rate. The DE algorithm was tested using a friction stir weld performed on a UNS S32205 Duplex Stainless Steel.

  17. Brand Equity Evolution: a System Dynamics Model

    Directory of Open Access Journals (Sweden)

    Edson Crescitelli

    2009-04-01

    Full Text Available One of the greatest challenges in brand management lies in monitoring brand equity over time. This paper aimsto present a simulation model able to represent this evolution. The model was drawn on brand equity concepts developed by Aaker and Joachimsthaler (2000, using the system dynamics methodology. The use ofcomputational dynamic models aims to create new sources of information able to sensitize academics and managers alike to the dynamic implications of their brand management. As a result, an easily implementable model was generated, capable of executing continuous scenario simulations by surveying casual relations among the variables that explain brand equity. Moreover, the existence of a number of system modeling tools will allow extensive application of the concepts used in this study in practical situations, both in professional and educational settings

  18. Galactic chemical evolution in hierarchical formation models

    Science.gov (United States)

    Arrigoni, Matias

    2010-10-01

    The chemical properties and abundance ratios of galaxies provide important information about their formation histories. Galactic chemical evolution has been modelled in detail within the monolithic collapse scenario. These models have successfully described the abundance distributions in our Galaxy and other spiral discs, as well as the trends of metallicity and abundance ratios observed in early-type galaxies. In the last three decades, however, the paradigm of hierarchical assembly in a Cold Dark Matter (CDM) cosmology has revised the picture of how structure in the Universe forms and evolves. In this scenario, galaxies form when gas radiatively cools and condenses inside dark matter haloes, which themselves follow dissipationless gravitational collapse. The CDM picture has been successful at predicting many observed properties of galaxies (for example, the luminosity and stellar mass function of galaxies, color-magnitude or star formation rate vs. stellar mass distributions, relative numbers of early and late-type galaxies, gas fractions and size distributions of spiral galaxies, and the global star formation history), though many potential problems and open questions remain. It is therefore interesting to see whether chemical evolution models, when implemented within this modern cosmological context, are able to correctly predict the observed chemical properties of galaxies. With the advent of more powerfull telescopes and detectors, precise observations of chemical abundances and abundance ratios in various phases (stellar, ISM, ICM) offer the opportunity to obtain strong constraints on galaxy formation histories and the physics that shapes them. However, in order to take advantage of these observations, it is necessary to implement detailed modeling of chemical evolution into a modern cosmological model of hierarchical assembly.

  19. Multiobjective optimization of an extremal evolution model

    International Nuclear Information System (INIS)

    Elettreby, M.F.

    2004-09-01

    We propose a two-dimensional model for a co-evolving ecosystem that generalizes the extremal coupled map lattice model. The model takes into account the concept of multiobjective optimization. We find that the system self-organizes into a critical state. The distributions of the distances between subsequent mutations as well as the distribution of avalanches sizes follow power law. (author)

  20. SURFACE AND LIGHTNING SOURCES OF NITROGEN OXIDES OVER THE UNITED STATES: MAGNITUDES, CHEMICAL EVOLUTION, AND OUTFLOW

    Science.gov (United States)

    We use observations from two aircraft during the ICARTT campaign over the eastern United States and North Atlantic during summer 2004, interpreted with a global 3-D model of tropospheric chemistry (GEOS-Chem) to test current understanding of regional sources, chemical evolution...

  1. Evolution of Cygnus X-3 through its Radio and X-ray States

    International Nuclear Information System (INIS)

    Szostek, A.; Zdziarski, A. A.; McCollough, M. L.

    2009-01-01

    Based on X-ray spectra and studies of the long-term correlated behavior between radio and soft X-ray, we present a detailed evolution of Cyg X-3 through its radio and X-ray states. We comment on the nature of the hard X-ray tail and possible Simbol X contribution in constraining the models.

  2. Evolution of Cygnus X-3 through its Radio and X-ray States

    Science.gov (United States)

    Szostek, A.; Zdziarski, A. A.; McCollough, M. L.

    2009-05-01

    Based on X-ray spectra and studies of the long-term correlated behavior between radio and soft X-ray, we present a detailed evolution of Cyg X-3 through its radio and X-ray states. We comment on the nature of the hard X-ray tail and possible Simbol X contribution in constraining the models.

  3. A model for simulation of coupled microstructural and compositional evolution

    International Nuclear Information System (INIS)

    Tikare, Veena; Homer, Eric R.; Holm, Elizabeth A.

    2011-01-01

    The formation, transport and segregation of components in nuclear fuels fundamentally control their behavior, performance, longevity and safety. Most nuclear fuels enter service with a uniform composition consisting of a single phase with two or three components. Fission products form, introducing more components. The segregation and transport of the components is complicated by the underlying microstructure consisting of grains, pores, bubbles and more, which is evolving under temperature gradients during service. As they evolve, components and microstructural features interact such that composition affects microstructure and vice versa. The ability to predict the interdependent compositional and microstructural evolution in 3D as a function of burn-up would greatly improve the ability to design safe, high burn-up nuclear fuels. We present a model that combines elements of Potts Monte Carlo, MC, and the phase-field model to treat coupled microstructural-compositional evolution. This hybrid model uses an equation of state, EOS, based on the microstructural state and the composition. The microstructural portion uses the traditional MC EOS and the compositional portion uses the phase-field EOS: E hyb = N Σ i=1 (E v (q i ,C)+1/2 n Σ j=1 J(q i ,q j )) + ∫κ c (∇C) 2 dV. E v is the bulk free energy of each site i and J is the bond energy between neighboring sites i and j; thus, this term defines the microstructural interfacial energy. The last term is the compositional interfacial energy as defined in the traditional phase-field model. Evolution of coupled microstructure-composition is simulated by minimizing free energy in a path dependent manner. This model will be presented and will be demonstrated by applying it to evolution of nuclear fuels during service. (author)

  4. Pechukas-Yukawa approach to the evolution of the quantum state of a parametrically perturbed system

    Science.gov (United States)

    Qureshi, Mumnuna A.; Zhong, Johnny; Qureshi, Zihad; Mason, Peter; Betouras, Joseph J.; Zagoskin, Alexandre M.

    2018-03-01

    We consider the evolution of the quantum states of a Hamiltonian that is parametrically perturbed via a term proportional to the adiabatic parameter λ (t ) . Starting with the Pechukas-Yukawa mapping of the energy eigenvalue evolution in a generalized Calogero-Sutherland model of a one-dimensional classical gas, we consider the adiabatic approximation with two different expansions of the quantum state in powers of d λ /d t and compare them with a direct numerical simulation. We show that one of these expansions (Magnus series) is especially convenient for the description of nonadiabatic evolution of the system. Applying the expansion to the exact cover 3-satisfiability problem, we obtain the occupation dynamics, which provides insight into the population of states and sources of decoherence in a quantum system.

  5. Mathematical models of ecology and evolution

    DEFF Research Database (Denmark)

    Zhang, Lai

    2012-01-01

    -history processes: net-assimilation mechanism of 􀀀rule and net-reproduction mechanism of size dependence using a simple model comprising a size-structured consumer Daphina and an unstructured resource alge. It is found that in contrast to the former mechanism, the latter tends to destabilize population...... dynamics but as a trade-o promotes species survival by shortening juvenile delay between birth and the onset of reproduction. Paper II compares the size-spectrum and food-web representations of communities using two traits (body size and habitat location) based unstructured population model of Lotka......) based size-structured population model, that is, interference in foraging, maintenance, survival, and recruitment. Their impacts on the ecology and evolution of size-structured populations and communities are explored. Ecologically, interference aects population demographic properties either negatively...

  6. A Distributed Snow Evolution Modeling System (SnowModel)

    Science.gov (United States)

    Liston, G. E.; Elder, K.

    2004-12-01

    A spatially distributed snow-evolution modeling system (SnowModel) has been specifically designed to be applicable over a wide range of snow landscapes, climates, and conditions. To reach this goal, SnowModel is composed of four sub-models: MicroMet defines the meteorological forcing conditions, EnBal calculates surface energy exchanges, SnowMass simulates snow depth and water-equivalent evolution, and SnowTran-3D accounts for snow redistribution by wind. While other distributed snow models exist, SnowModel is unique in that it includes a well-tested blowing-snow sub-model (SnowTran-3D) for application in windy arctic, alpine, and prairie environments where snowdrifts are common. These environments comprise 68% of the seasonally snow-covered Northern Hemisphere land surface. SnowModel also accounts for snow processes occurring in forested environments (e.g., canopy interception related processes). SnowModel is designed to simulate snow-related physical processes occurring at spatial scales of 5-m and greater, and temporal scales of 1-hour and greater. These include: accumulation from precipitation; wind redistribution and sublimation; loading, unloading, and sublimation within forest canopies; snow-density evolution; and snowpack ripening and melt. To enhance its wide applicability, SnowModel includes the physical calculations required to simulate snow evolution within each of the global snow classes defined by Sturm et al. (1995), e.g., tundra, taiga, alpine, prairie, maritime, and ephemeral snow covers. The three, 25-km by 25-km, Cold Land Processes Experiment (CLPX) mesoscale study areas (MSAs: Fraser, North Park, and Rabbit Ears) are used as SnowModel simulation examples to highlight model strengths, weaknesses, and features in forested, semi-forested, alpine, and shrubland environments.

  7. UNCERTAINTIES IN GALACTIC CHEMICAL EVOLUTION MODELS

    International Nuclear Information System (INIS)

    Côté, Benoit; Ritter, Christian; Herwig, Falk; O’Shea, Brian W.; Pignatari, Marco; Jones, Samuel; Fryer, Chris L.

    2016-01-01

    We use a simple one-zone galactic chemical evolution model to quantify the uncertainties generated by the input parameters in numerical predictions for a galaxy with properties similar to those of the Milky Way. We compiled several studies from the literature to gather the current constraints for our simulations regarding the typical value and uncertainty of the following seven basic parameters: the lower and upper mass limits of the stellar initial mass function (IMF), the slope of the high-mass end of the stellar IMF, the slope of the delay-time distribution function of Type Ia supernovae (SNe Ia), the number of SNe Ia per M ⊙ formed, the total stellar mass formed, and the final mass of gas. We derived a probability distribution function to express the range of likely values for every parameter, which were then included in a Monte Carlo code to run several hundred simulations with randomly selected input parameters. This approach enables us to analyze the predicted chemical evolution of 16 elements in a statistical manner by identifying the most probable solutions, along with their 68% and 95% confidence levels. Our results show that the overall uncertainties are shaped by several input parameters that individually contribute at different metallicities, and thus at different galactic ages. The level of uncertainty then depends on the metallicity and is different from one element to another. Among the seven input parameters considered in this work, the slope of the IMF and the number of SNe Ia are currently the two main sources of uncertainty. The thicknesses of the uncertainty bands bounded by the 68% and 95% confidence levels are generally within 0.3 and 0.6 dex, respectively. When looking at the evolution of individual elements as a function of galactic age instead of metallicity, those same thicknesses range from 0.1 to 0.6 dex for the 68% confidence levels and from 0.3 to 1.0 dex for the 95% confidence levels. The uncertainty in our chemical evolution model

  8. A Mudball Model for the Evolution of Carbonaceous Asteroids

    Science.gov (United States)

    Travis, B. J.; Bland, P. A.

    2018-05-01

    We simulation the evolution of carbonaceous chondrite parent bodies from initially unconsolidated aggregations of rock grains and ice crystals. Application of the numerical model MAGHNUM to evolution of CM type planetesimals and Ceres is described.

  9. Time evolution of quenched state and correlation to glassy effects

    International Nuclear Information System (INIS)

    Kilic, K.; Kilic, A.; Altinkok, A.; Yetis, H.; Cetin, O.; Durust, Y.

    2005-01-01

    In this work, dynamic changes generated by the driving current were studied in superconducting bulk polycrystalline YBCO sample via transport relaxation measurements (V-t curves). The evolution of nonlinear V-t curves was interpreted in terms of the formation of resistive and nonresistive flow channels and the spatial reorganization of the transport current in a multiply connected network of weak-link structure. The dynamic re-organization of driving current could cause an enhancement or suppression in the superconducting order parameter due to the magnitude of the driving current and coupling strength of weak-link structure along with the chemical and anisotropic states of the sample as the time proceeds. A nonzero voltage decaying with time, correlated to the quenched state, was recorded when the magnitude of initial driving current is reduced to a finite value. It was found that, after sufficiently long waiting time, the evolution of the quenched state could result in a superconducting state, depending on the magnitude of the driving current and temperature. We showed that the decays in voltage over time are consistent with an exponential time dependence which is related to the glassy state. Further, the effect of doping of organic material Bis dimethyl-glyoximato Copper (II) to YBCO could be monitored apparently via the comparison of the V-t curves corresponding to doped and undoped YBCO samples

  10. A Nonstationary Markov Model Detects Directional Evolution in Hymenopteran Morphology.

    Science.gov (United States)

    Klopfstein, Seraina; Vilhelmsen, Lars; Ronquist, Fredrik

    2015-11-01

    Directional evolution has played an important role in shaping the morphological, ecological, and molecular diversity of life. However, standard substitution models assume stationarity of the evolutionary process over the time scale examined, thus impeding the study of directionality. Here we explore a simple, nonstationary model of evolution for discrete data, which assumes that the state frequencies at the root differ from the equilibrium frequencies of the homogeneous evolutionary process along the rest of the tree (i.e., the process is nonstationary, nonreversible, but homogeneous). Within this framework, we develop a Bayesian approach for testing directional versus stationary evolution using a reversible-jump algorithm. Simulations show that when only data from extant taxa are available, the success in inferring directionality is strongly dependent on the evolutionary rate, the shape of the tree, the relative branch lengths, and the number of taxa. Given suitable evolutionary rates (0.1-0.5 expected substitutions between root and tips), accounting for directionality improves tree inference and often allows correct rooting of the tree without the use of an outgroup. As an empirical test, we apply our method to study directional evolution in hymenopteran morphology. We focus on three character systems: wing veins, muscles, and sclerites. We find strong support for a trend toward loss of wing veins and muscles, while stationarity cannot be ruled out for sclerites. Adding fossil and time information in a total-evidence dating approach, we show that accounting for directionality results in more precise estimates not only of the ancestral state at the root of the tree, but also of the divergence times. Our model relaxes the assumption of stationarity and reversibility by adding a minimum of additional parameters, and is thus well suited to studying the nature of the evolutionary process in data sets of limited size, such as morphology and ecology. © The Author

  11. Genealogies in simple models of evolution

    International Nuclear Information System (INIS)

    Brunet, Éric; Derrida, Bernard

    2013-01-01

    We review the statistical properties of the genealogies of a few models of evolution. In the asexual case, selection leads to coalescence times which grow logarithmically with the size of the population, in contrast with the linear growth of the neutral case. Moreover for a whole class of models, the statistics of the genealogies are those of the Bolthausen–Sznitman coalescent rather than the Kingman coalescent in the neutral case. For sexual reproduction in the neutral case, the time to reach the first common ancestors for the whole population and the time for all individuals to have all their ancestors in common are also logarithmic in the population size, as predicted by Chang in 1999. We discuss how these times are modified by introducing selection in a simple way. (paper)

  12. Evolution model with a cumulative feedback coupling

    Science.gov (United States)

    Trimper, Steffen; Zabrocki, Knud; Schulz, Michael

    2002-05-01

    The paper is concerned with a toy model that generalizes the standard Lotka-Volterra equation for a certain population by introducing a competition between instantaneous and accumulative, history-dependent nonlinear feedback the origin of which could be a contribution from any kind of mismanagement in the past. The results depend on the sign of that additional cumulative loss or gain term of strength λ. In case of a positive coupling the system offers a maximum gain achieved after a finite time but the population will die out in the long time limit. In this case the instantaneous loss term of strength u is irrelevant and the model exhibits an exact solution. In the opposite case λ<0 the time evolution of the system is terminated in a crash after ts provided u=0. This singularity after a finite time can be avoided if u≠0. The approach may well be of relevance for the qualitative understanding of more realistic descriptions.

  13. Topological bifurcations in the evolution of coherent structures in a convection model

    DEFF Research Database (Denmark)

    Dam, Magnus; Rasmussen, Jens Juul; Naulin, Volker

    2017-01-01

    Blob filaments are coherent structures in a turbulent plasma flow. Understanding the evolution of these structures is important to improve magnetic plasma confinement. Three state variables describe blob filaments in a plasma convection model. A dynamical systems approach analyzes the evolution...

  14. A model for evolution of overlapping community networks

    Science.gov (United States)

    Karan, Rituraj; Biswal, Bibhu

    2017-05-01

    A model is proposed for the evolution of network topology in social networks with overlapping community structure. Starting from an initial community structure that is defined in terms of group affiliations, the model postulates that the subsequent growth and loss of connections is similar to the Hebbian learning and unlearning in the brain and is governed by two dominant factors: the strength and frequency of interaction between the members, and the degree of overlap between different communities. The temporal evolution from an initial community structure to the current network topology can be described based on these two parameters. It is possible to quantify the growth occurred so far and predict the final stationary state to which the network is likely to evolve. Applications in epidemiology or the spread of email virus in a computer network as well as finding specific target nodes to control it are envisaged. While facing the challenge of collecting and analyzing large-scale time-resolved data on social groups and communities one faces the most basic questions: how do communities evolve in time? This work aims to address this issue by developing a mathematical model for the evolution of community networks and studying it through computer simulation.

  15. Phenotypic heterogeneity in modeling cancer evolution.

    Directory of Open Access Journals (Sweden)

    Ali Mahdipour-Shirayeh

    Full Text Available The unwelcome evolution of malignancy during cancer progression emerges through a selection process in a complex heterogeneous population structure. In the present work, we investigate evolutionary dynamics in a phenotypically heterogeneous population of stem cells (SCs and their associated progenitors. The fate of a malignant mutation is determined not only by overall stem cell and non-stem cell growth rates but also differentiation and dedifferentiation rates. We investigate the effect of such a complex population structure on the evolution of malignant mutations. We derive exactly calculated results for the fixation probability of a mutant arising in each of the subpopulations. The exactly calculated results are in almost perfect agreement with the numerical simulations. Moreover, a condition for evolutionary advantage of a mutant cell versus the wild type population is given in the present study. We also show that microenvironment-induced plasticity in invading mutants leads to more aggressive mutants with higher fixation probability. Our model predicts that decreasing polarity between stem and non-stem cells' turnover would raise the survivability of non-plastic mutants; while it would suppress the development of malignancy for plastic mutants. The derived results are novel and general with potential applications in nature; we discuss our model in the context of colorectal/intestinal cancer (at the epithelium. However, the model clearly needs to be validated through appropriate experimental data. This novel mathematical framework can be applied more generally to a variety of problems concerning selection in heterogeneous populations, in other contexts such as population genetics, and ecology.

  16. Nonclassical thermal-state superpositions: Analytical evolution law and decoherence behavior

    Science.gov (United States)

    Meng, Xiang-guo; Goan, Hsi-Sheng; Wang, Ji-suo; Zhang, Ran

    2018-03-01

    Employing the integration technique within normal products of bosonic operators, we present normal product representations of thermal-state superpositions and investigate their nonclassical features, such as quadrature squeezing, sub-Poissonian distribution, and partial negativity of the Wigner function. We also analytically and numerically investigate their evolution law and decoherence characteristics in an amplitude-decay model via the variations of the probability distributions and the negative volumes of Wigner functions in phase space. The results indicate that the evolution formulas of two thermal component states for amplitude decay can be viewed as the same integral form as a displaced thermal state ρ(V , d) , but governed by the combined action of photon loss and thermal noise. In addition, the larger values of the displacement d and noise V lead to faster decoherence for thermal-state superpositions.

  17. Monitoring of atherosclerosis evolution by detection of inflammatory states of aortae in a rabbit model using 18F-FDG -PET/CT

    International Nuclear Information System (INIS)

    Zhao, Q.-M.; Zhao, X.; Feng, T.-T.; Zhang, M.-D.; Zhuang, X.-C.; Zhao, X.-C.; Zhang, X.-X.; Su, G.

    2014-01-01

    In vivo dynamic evaluation of atherosclerosis could be clinically significant in the prevention of cardiovascular events. We aimed to monitor Fluorine-18 fluorodeoxyglucose (18F-FDG) uptake in different stages of atherosclerosis, and investigate the feasibility of detecting vulnerable plaques using positron emission tomography/computed tomography (PET/CT) angiography. Twenty-two male NZW rabbits were divided into two groups: atherosclerosis group (group A, N.=11) and atherosclerosis and statin group (group S, N.=11). The rabbits underwent two pharmacological triggerings to induce thrombus at the 18. week. In vivo PET/CT scans were performed on four time points: before cholesterol diet (baseline, N.=6), at 8. week (the middle-of-feding, N.=4), at 18. week (the end-of-feeding, N.=22) and after triggering (post-triggering, N.=15). 18F-FDG uptake by the aorta was expressed as maximal standardized uptake value (SUVmax) and mean SUV (SUV mean ). SUVs were measured on serial 7.5 mm arterial segments. SUV mean and SUV max were 0.449±0.108 and 0.550±0.132 at baseline, 0.694±0.117 and 0.754±0.129 at the middle-of-feeding, 0.788±0.121 and 0.861±0.139 in group A, and 0.651±0.194 and 0.736±0.243 in group S at the end-of feeding before triggering. SUV mean and SUV max were 1.128±0.420 and 1.302±0.489 in thrombosis group, 0.774±0.159 and 0.859±0.191 in non-thrombosis group after triggering. Thrombus were identified in 10 of 22 rabbits (45.5%): 8 of 11 (72.3%) in group A, and 2 of 11 (18.2%) in group S (P<0.001). The inflammatory states of atherosclerosis and vulnerable plaque can be detected by quantitative analysis of 18F-FDG uptake. PET/CT may be used for predicting thrombosis events in patients with atherosclerotic disease

  18. The Impact of Modeling Assumptions in Galactic Chemical Evolution Models

    Science.gov (United States)

    Côté, Benoit; O'Shea, Brian W.; Ritter, Christian; Herwig, Falk; Venn, Kim A.

    2017-02-01

    We use the OMEGA galactic chemical evolution code to investigate how the assumptions used for the treatment of galactic inflows and outflows impact numerical predictions. The goal is to determine how our capacity to reproduce the chemical evolution trends of a galaxy is affected by the choice of implementation used to include those physical processes. In pursuit of this goal, we experiment with three different prescriptions for galactic inflows and outflows and use OMEGA within a Markov Chain Monte Carlo code to recover the set of input parameters that best reproduces the chemical evolution of nine elements in the dwarf spheroidal galaxy Sculptor. This provides a consistent framework for comparing the best-fit solutions generated by our different models. Despite their different degrees of intended physical realism, we found that all three prescriptions can reproduce in an almost identical way the stellar abundance trends observed in Sculptor. This result supports the similar conclusions originally claimed by Romano & Starkenburg for Sculptor. While the three models have the same capacity to fit the data, the best values recovered for the parameters controlling the number of SNe Ia and the strength of galactic outflows, are substantially different and in fact mutually exclusive from one model to another. For the purpose of understanding how a galaxy evolves, we conclude that only reproducing the evolution of a limited number of elements is insufficient and can lead to misleading conclusions. More elements or additional constraints such as the Galaxy’s star-formation efficiency and the gas fraction are needed in order to break the degeneracy between the different modeling assumptions. Our results show that the successes and failures of chemical evolution models are predominantly driven by the input stellar yields, rather than by the complexity of the Galaxy model itself. Simple models such as OMEGA are therefore sufficient to test and validate stellar yields. OMEGA

  19. A 'Turing' Test for Landscape Evolution Models

    Science.gov (United States)

    Parsons, A. J.; Wise, S. M.; Wainwright, J.; Swift, D. A.

    2008-12-01

    Resolving the interactions among tectonics, climate and surface processes at long timescales has benefited from the development of computer models of landscape evolution. However, testing these Landscape Evolution Models (LEMs) has been piecemeal and partial. We argue that a more systematic approach is required. What is needed is a test that will establish how 'realistic' an LEM is and thus the extent to which its predictions may be trusted. We propose a test based upon the Turing Test of artificial intelligence as a way forward. In 1950 Alan Turing posed the question of whether a machine could think. Rather than attempt to address the question directly he proposed a test in which an interrogator asked questions of a person and a machine, with no means of telling which was which. If the machine's answer could not be distinguished from those of the human, the machine could be said to demonstrate artificial intelligence. By analogy, if an LEM cannot be distinguished from a real landscape it can be deemed to be realistic. The Turing test of intelligence is a test of the way in which a computer behaves. The analogy in the case of an LEM is that it should show realistic behaviour in terms of form and process, both at a given moment in time (punctual) and in the way both form and process evolve over time (dynamic). For some of these behaviours, tests already exist. For example there are numerous morphometric tests of punctual form and measurements of punctual process. The test discussed in this paper provides new ways of assessing dynamic behaviour of an LEM over realistically long timescales. However challenges remain in developing an appropriate suite of challenging tests, in applying these tests to current LEMs and in developing LEMs that pass them.

  20. Random unitary evolution model of quantum Darwinism with pure decoherence

    Science.gov (United States)

    Balanesković, Nenad

    2015-10-01

    We study the behavior of Quantum Darwinism [W.H. Zurek, Nat. Phys. 5, 181 (2009)] within the iterative, random unitary operations qubit-model of pure decoherence [J. Novotný, G. Alber, I. Jex, New J. Phys. 13, 053052 (2011)]. We conclude that Quantum Darwinism, which describes the quantum mechanical evolution of an open system S from the point of view of its environment E, is not a generic phenomenon, but depends on the specific form of input states and on the type of S-E-interactions. Furthermore, we show that within the random unitary model the concept of Quantum Darwinism enables one to explicitly construct and specify artificial input states of environment E that allow to store information about an open system S of interest with maximal efficiency.

  1. Social Factors of the Evolution of State Institutions

    Directory of Open Access Journals (Sweden)

    Zhukova Larysa M.

    2017-06-01

    Full Text Available The aim of the article is a comprehensive study of social factors in the evolution of state institutions. By analyzing, systematizing and summarizing the scientific works of many scientists, the process of transformation of state institutions is considered in view of the features of Ukraine’s social and economic development and the impact of institutional changes on the social needs of society. As a result of the research, it is revealed that one of the main factors of social evolution is the culture of relations between the state, business and society. The logical and contradictory interaction of these subjects is analyzed, since based on them there formed an economy aimed at reviving social resources and ensuring both the stability of the social system and the dynamism of its development. It is determined that Ukraine requires urgent development of an integrated socio-economic development strategy that would include specific measures that can ensure improvement of the living standards of citizens, creation of a competitive economy, successful integration into the world and European space. It is substantiated that the system of relations “state – business – society” should be revised from the position of strengthening the importance of both social values and the business community facing the challenges of globalization. Prospects for further research in this area are justification of the strategic goals of the state social policy as a multi-level and multifunctional system that can ensure the country’s social and economic development by activating human capital and maximizing its innovative potential.

  2. From Product Models to Product State Models

    DEFF Research Database (Denmark)

    Larsen, Michael Holm

    1999-01-01

    A well-known technology designed to handle product data is Product Models. Product Models are in their current form not able to handle all types of product state information. Hence, the concept of a Product State Model (PSM) is proposed. The PSM and in particular how to model a PSM is the Research...

  3. Genetic Models in Evolutionary Game Theory: The Evolution of Altruism

    NARCIS (Netherlands)

    Rubin, Hannah

    2015-01-01

    While prior models of the evolution of altruism have assumed that organisms reproduce asexually, this paper presents a model of the evolution of altruism for sexually reproducing organisms using Hardy–Weinberg dynamics. In this model, the presence of reciprocal altruists allows the population to

  4. Bound states for non-symmetric evolution Schroedinger potentials

    Energy Technology Data Exchange (ETDEWEB)

    Corona, Gulmaro Corona [Area de Analisis Matematico y sus Aplicaciones, Universidad Autonoma Metropolitana-Azcapotalco, Atzcapotzalco, DF (Mexico)). E-mail: ccg@correo.azc.uam.mx

    2001-09-14

    We consider the spectral problem associated with the evolution Schroedinger equation, (D{sup 2}+ k{sup 2}){phi}=u{phi}, where u is a matrix-square-valued function, with entries in the Schwartz class defined on the real line. The solution {phi}, called the wavefunction, consists of a function of one real variable, matrix-square-valued with entries in the Schwartz class. This problem has been dealt for symmetric potentials u. We found for the present case that the bound states are localized similarly to the scalar and symmetric cases, but by the zeroes of an analytic matrix-valued function. If we add an extra condition to the potential u, we can determine these states by an analytic scalar function. We do this by generalizing the scalar and symmetric cases but without using the fact that the Wronskian of a pair of wavefunction is constant. (author)

  5. Energetics in a model of prebiotic evolution

    Science.gov (United States)

    Intoy, B. F.; Halley, J. W.

    2017-12-01

    Previously we reported [A. Wynveen et al., Phys. Rev. E 89, 022725 (2014), 10.1103/PhysRevE.89.022725] that requiring that the systems regarded as lifelike be out of chemical equilibrium in a model of abstracted polymers undergoing ligation and scission first introduced by Kauffman [S. A. Kauffman, The Origins of Order (Oxford University Press, New York, 1993), Chap. 7] implied that lifelike systems were most probable when the reaction network was sparse. The model was entirely statistical and took no account of the bond energies or other energetic constraints. Here we report results of an extension of the model to include effects of a finite bonding energy in the model. We studied two conditions: (1) A food set is continuously replenished and the total polymer population is constrained but the system is otherwise isolated and (2) in addition to the constraints in (1) the system is in contact with a finite-temperature heat bath. In each case, detailed balance in the dynamics is guaranteed during the computations by continuous recomputation of a temperature [in case (1)] and of the chemical potential (in both cases) toward which the system is driven by the dynamics. In the isolated case, the probability of reaching a metastable nonequilibrium state in this model depends significantly on the composition of the food set, and the nonequilibrium states satisfying lifelike condition turn out to be at energies and particle numbers consistent with an equilibrium state at high negative temperature. As a function of the sparseness of the reaction network, the lifelike probability is nonmonotonic, as in our previous model, but the maximum probability occurs when the network is less sparse. In the case of contact with a thermal bath at a positive ambient temperature, we identify two types of metastable nonequilibrium states, termed locally and thermally alive, and locally dead and thermally alive, and evaluate their likelihood of appearance, finding maxima at an optimal

  6. Evolution, present state and future of the radiochromic dyeing films

    International Nuclear Information System (INIS)

    Villarreal B, J.E.

    2000-01-01

    The evolution of radiochromic films, their present state and their developing future are the object of this work. For this purpose a review of the evolution was realized and also of the present state of using the radiochromic dyeing films as tools to determine the absorbed doses distribution produces by beta emissor sources, beta-gamma, electrons and X-rays. In particular it is presented the development of radiochromic films type GafChromic that by their quality in terms of reproducibility, sensibility and high spatial resolution they have been converted in those films of greatest use so dominating market. Since one of the application fields more important of this type of films is clinical dosimetry, the more eminent applications in this area are presented, which the high resolution dosimetry that use GafChromic has been converted in a basic tool. On the other hand the scopes of this type of dosimetry and the possible development lines of dosimetry with radiochromic dyeing films are discussed. (Author)

  7. Extending the enterprise evolution contextualisation model

    Science.gov (United States)

    de Vries, Marné; van der Merwe, Alta; Gerber, Aurona

    2017-07-01

    Enterprise engineering (EE) emerged as a new discipline to encourage comprehensive and consistent enterprise design. Since EE is multidisciplinary, various researchers study enterprises from different perspectives, which resulted in a plethora of applicable literature and terminology, but without shared meaning. Previous research specifically focused on the fragmentation of knowledge for designing and aligning the information and communication technology (ICT) subsystem of the enterprise in order to support the business organisation subsystem of the enterprise. As a solution for this fragmented landscape, a business-IT alignment model (BIAM) was developed inductively from existing business-IT alignment approaches. Since most of the existing alignment frameworks addressed the alignment between the ICT subsystem and the business organisation subsystem, BIAM also focused on the alignment between these two subsystems. Yet, the emerging EE discipline intends to address a broader scope of design, evident in the existing approaches that incorporate a broader scope of design/alignment/governance. A need was identified to address the knowledge fragmentation of the EE knowledge base by adapting BIAM to an enterprise evolution contextualisation model (EECM), to contextualise a broader set of approaches, as identified by Lapalme. The main contribution of this article is the incremental development and evaluation of EECM. We also present guiding indicators/prerequisites for applying EECM as a contextualisation tool.

  8. Evolution of tripartite entangled states in a decohering environment and their experimental protection using dynamical decoupling

    Science.gov (United States)

    Singh, Harpreet; Arvind, Dorai, Kavita

    2018-02-01

    We embarked upon the task of experimental protection of different classes of tripartite entangled states, namely, the maximally entangled Greenberger-Horne-Zeilinger (GHZ) and W states and the tripartite entangled state called the W W ¯ state, using dynamical decoupling. The states were created on a three-qubit NMR quantum information processor and allowed to evolve in the naturally noisy NMR environment. Tripartite entanglement was monitored at each time instant during state evolution, using negativity as an entanglement measure. It was found that the W state is most robust while the GHZ-type states are most fragile against the natural decoherence present in the NMR system. The W W ¯ state, which is in the GHZ class yet stores entanglement in a manner akin to the W state, surprisingly turned out to be more robust than the GHZ state. The experimental data were best modeled by considering the main noise channel to be an uncorrelated phase damping channel acting independently on each qubit, along with a generalized amplitude damping channel. Using dynamical decoupling, we were able to achieve a significant protection of entanglement for GHZ states. There was a marginal improvement in the state fidelity for the W state (which is already robust against natural system decoherence), while the W W ¯ state showed a significant improvement in fidelity and protection against decoherence.

  9. Analytic models for the evolution of semilocal string networks

    International Nuclear Information System (INIS)

    Nunes, A. S.; Martins, C. J. A. P.; Avgoustidis, A.; Urrestilla, J.

    2011-01-01

    We revisit previously developed analytic models for defect evolution and adapt them appropriately for the study of semilocal string networks. We thus confirm the expectation (based on numerical simulations) that linear scaling evolution is the attractor solution for a broad range of model parameters. We discuss in detail the evolution of individual semilocal segments, focusing on the phenomenology of segment growth, and also provide a preliminary comparison with existing numerical simulations.

  10. Dynamic and quantitative method of analyzing service consistency evolution based on extended hierarchical finite state automata.

    Science.gov (United States)

    Fan, Linjun; Tang, Jun; Ling, Yunxiang; Li, Benxian

    2014-01-01

    This paper is concerned with the dynamic evolution analysis and quantitative measurement of primary factors that cause service inconsistency in service-oriented distributed simulation applications (SODSA). Traditional methods are mostly qualitative and empirical, and they do not consider the dynamic disturbances among factors in service's evolution behaviors such as producing, publishing, calling, and maintenance. Moreover, SODSA are rapidly evolving in terms of large-scale, reusable, compositional, pervasive, and flexible features, which presents difficulties in the usage of traditional analysis methods. To resolve these problems, a novel dynamic evolution model extended hierarchical service-finite state automata (EHS-FSA) is constructed based on finite state automata (FSA), which formally depict overall changing processes of service consistency states. And also the service consistency evolution algorithms (SCEAs) based on EHS-FSA are developed to quantitatively assess these impact factors. Experimental results show that the bad reusability (17.93% on average) is the biggest influential factor, the noncomposition of atomic services (13.12%) is the second biggest one, and the service version's confusion (1.2%) is the smallest one. Compared with previous qualitative analysis, SCEAs present good effectiveness and feasibility. This research can guide the engineers of service consistency technologies toward obtaining a higher level of consistency in SODSA.

  11. Dynamic and Quantitative Method of Analyzing Service Consistency Evolution Based on Extended Hierarchical Finite State Automata

    Directory of Open Access Journals (Sweden)

    Linjun Fan

    2014-01-01

    Full Text Available This paper is concerned with the dynamic evolution analysis and quantitative measurement of primary factors that cause service inconsistency in service-oriented distributed simulation applications (SODSA. Traditional methods are mostly qualitative and empirical, and they do not consider the dynamic disturbances among factors in service’s evolution behaviors such as producing, publishing, calling, and maintenance. Moreover, SODSA are rapidly evolving in terms of large-scale, reusable, compositional, pervasive, and flexible features, which presents difficulties in the usage of traditional analysis methods. To resolve these problems, a novel dynamic evolution model extended hierarchical service-finite state automata (EHS-FSA is constructed based on finite state automata (FSA, which formally depict overall changing processes of service consistency states. And also the service consistency evolution algorithms (SCEAs based on EHS-FSA are developed to quantitatively assess these impact factors. Experimental results show that the bad reusability (17.93% on average is the biggest influential factor, the noncomposition of atomic services (13.12% is the second biggest one, and the service version’s confusion (1.2% is the smallest one. Compared with previous qualitative analysis, SCEAs present good effectiveness and feasibility. This research can guide the engineers of service consistency technologies toward obtaining a higher level of consistency in SODSA.

  12. modelling of directed evolution: Implications for experimental design and stepwise evolution

    OpenAIRE

    Wedge , David C.; Rowe , William; Kell , Douglas B.; Knowles , Joshua

    2009-01-01

    In silico modelling of directed evolution: Implications for experimental design and stepwise evolution correspondence: Corresponding author. Tel.: +441613065145. (Wedge, David C.) (Wedge, David C.) Manchester Interdisciplinary Biocentre, University of Manchester - 131 Princess Street--> , Manchester--> , M1 7ND--> - UNITED KINGDOM (Wedge, David C.) UNITED KINGDOM (Wedge, David C.) Man...

  13. Evolution of quantum-like modeling in decision making processes

    Science.gov (United States)

    Khrennikova, Polina

    2012-12-01

    The application of the mathematical formalism of quantum mechanics to model behavioral patterns in social science and economics is a novel and constantly emerging field. The aim of the so called 'quantum like' models is to model the decision making processes in a macroscopic setting, capturing the particular 'context' in which the decisions are taken. Several subsequent empirical findings proved that when making a decision people tend to violate the axioms of expected utility theory and Savage's Sure Thing principle, thus violating the law of total probability. A quantum probability formula was devised to describe more accurately the decision making processes. A next step in the development of QL-modeling in decision making was the application of Schrödinger equation to describe the evolution of people's mental states. A shortcoming of Schrödinger equation is its inability to capture dynamics of an open system; the brain of the decision maker can be regarded as such, actively interacting with the external environment. Recently the master equation, by which quantum physics describes the process of decoherence as the result of interaction of the mental state with the environmental 'bath', was introduced for modeling the human decision making. The external environment and memory can be referred to as a complex 'context' influencing the final decision outcomes. The master equation can be considered as a pioneering and promising apparatus for modeling the dynamics of decision making in different contexts.

  14. Evolution of quantum-like modeling in decision making processes

    Energy Technology Data Exchange (ETDEWEB)

    Khrennikova, Polina [School of Management, University of Leicester, University Road Leicester LE1 7RH (United Kingdom)

    2012-12-18

    The application of the mathematical formalism of quantum mechanics to model behavioral patterns in social science and economics is a novel and constantly emerging field. The aim of the so called 'quantum like' models is to model the decision making processes in a macroscopic setting, capturing the particular 'context' in which the decisions are taken. Several subsequent empirical findings proved that when making a decision people tend to violate the axioms of expected utility theory and Savage's Sure Thing principle, thus violating the law of total probability. A quantum probability formula was devised to describe more accurately the decision making processes. A next step in the development of QL-modeling in decision making was the application of Schroedinger equation to describe the evolution of people's mental states. A shortcoming of Schroedinger equation is its inability to capture dynamics of an open system; the brain of the decision maker can be regarded as such, actively interacting with the external environment. Recently the master equation, by which quantum physics describes the process of decoherence as the result of interaction of the mental state with the environmental 'bath', was introduced for modeling the human decision making. The external environment and memory can be referred to as a complex 'context' influencing the final decision outcomes. The master equation can be considered as a pioneering and promising apparatus for modeling the dynamics of decision making in different contexts.

  15. Evolution of quantum-like modeling in decision making processes

    International Nuclear Information System (INIS)

    Khrennikova, Polina

    2012-01-01

    The application of the mathematical formalism of quantum mechanics to model behavioral patterns in social science and economics is a novel and constantly emerging field. The aim of the so called 'quantum like' models is to model the decision making processes in a macroscopic setting, capturing the particular 'context' in which the decisions are taken. Several subsequent empirical findings proved that when making a decision people tend to violate the axioms of expected utility theory and Savage's Sure Thing principle, thus violating the law of total probability. A quantum probability formula was devised to describe more accurately the decision making processes. A next step in the development of QL-modeling in decision making was the application of Schrödinger equation to describe the evolution of people's mental states. A shortcoming of Schrödinger equation is its inability to capture dynamics of an open system; the brain of the decision maker can be regarded as such, actively interacting with the external environment. Recently the master equation, by which quantum physics describes the process of decoherence as the result of interaction of the mental state with the environmental 'bath', was introduced for modeling the human decision making. The external environment and memory can be referred to as a complex 'context' influencing the final decision outcomes. The master equation can be considered as a pioneering and promising apparatus for modeling the dynamics of decision making in different contexts.

  16. Modelling dune evolution and dynamic roughness in rivers

    NARCIS (Netherlands)

    Paarlberg, Andries

    2008-01-01

    Accurate river flow models are essential tools for water managers, but these hydraulic simulation models often lack a proper description of dynamic roughness due to hysteresis effects in dune evolution. To incorporate the effects of dune evolution directly into the resistance coefficients of

  17. New Parallel Algorithms for Landscape Evolution Model

    Science.gov (United States)

    Jin, Y.; Zhang, H.; Shi, Y.

    2017-12-01

    Most landscape evolution models (LEM) developed in the last two decades solve the diffusion equation to simulate the transportation of surface sediments. This numerical approach is difficult to parallelize due to the computation of drainage area for each node, which needs huge amount of communication if run in parallel. In order to overcome this difficulty, we developed two parallel algorithms for LEM with a stream net. One algorithm handles the partition of grid with traditional methods and applies an efficient global reduction algorithm to do the computation of drainage areas and transport rates for the stream net; the other algorithm is based on a new partition algorithm, which partitions the nodes in catchments between processes first, and then partitions the cells according to the partition of nodes. Both methods focus on decreasing communication between processes and take the advantage of massive computing techniques, and numerical experiments show that they are both adequate to handle large scale problems with millions of cells. We implemented the two algorithms in our program based on the widely used finite element library deal.II, so that it can be easily coupled with ASPECT.

  18. Generalized YORP evolution: Onset of tumbling and new asymptotic states

    Science.gov (United States)

    Vokrouhlický, D.; Breiter, S.; Nesvorný, D.; Bottke, W. F.

    2007-11-01

    Asteroids have a wide range of rotation states. While the majority spin a few times to several times each day in principal axis rotation, a small number spin so slowly that they have somehow managed to enter into a tumbling rotation state. Here we investigate whether the Yarkovsky-Radzievskii-O'Keefe-Paddack (YORP) thermal radiation effect could have produced these unusual spin states. To do this, we developed a Lie-Poisson integrator of the orbital and rotational motion of a model asteroid. Solar torques, YORP, and internal energy dissipation were included in our model. Using this code, we found that YORP can no longer drive the spin rates of bodies toward values infinitely close to zero. Instead, bodies losing too much rotation angular momentum fall into chaotic tumbling rotation states where the spin axis wanders randomly for some interval of time. Eventually, our model asteroids reach rotation states that approach regular motion of the spin axis in the body frame. An analytical model designed to describe this behavior does a good job of predicting how and when the onset of tumbling motion should take place. The question of whether a given asteroid will fall into a tumbling rotation state depends on the efficiency of its internal energy dissipation and on the precise way YORP modifies the spin rates of small bodies.

  19. Modeling multiscale evolution of numerous voids in shocked brittle material.

    Science.gov (United States)

    Yu, Yin; Wang, Wenqiang; He, Hongliang; Lu, Tiecheng

    2014-04-01

    The influence of the evolution of numerous voids on macroscopic properties of materials is a multiscale problem that challenges computational research. A shock-wave compression model for brittle material, which can obtain both microscopic evolution and macroscopic shock properties, was developed using discrete element methods (lattice model). Using a model interaction-parameter-mapping procedure, qualitative features, as well as trends in the calculated shock-wave profiles, are shown to agree with experimental results. The shock wave splits into an elastic wave and a deformation wave in porous brittle materials, indicating significant shock plasticity. Void collapses in the deformation wave were the natural reason for volume shrinkage and deformation. However, media slippage and rotation deformations indicated by complex vortex patterns composed of relative velocity vectors were also confirmed as an important source of shock plasticity. With increasing pressure, the contribution from slippage deformation to the final plastic strain increased. Porosity was found to determine the amplitude of the elastic wave; porosity and shock stress together determine propagation speed of the deformation wave, as well as stress and strain on the final equilibrium state. Thus, shock behaviors of porous brittle material can be systematically designed for specific applications.

  20. Unitarity and the time evolution of quantum mechanical states

    International Nuclear Information System (INIS)

    Kabir, P.K.; Pilaftsis, A.

    1996-01-01

    The basic requirement that, in quantum theory, the time evolution of any state is determined by the action of a unitary operator, is shown to be the underlying cause for certain open-quote open-quote exact close-quote close-quote results that have recently been reported about the time dependence of transition rates in quantum theory. Departures from exponential decay, including the open-quote open-quote quantum Zeno effect,close-quote close-quote as well as a theorem by Khalfin about the ratio of reciprocal transition rates, are shown to follow directly from such considerations. At sufficiently short times, unitarity requires that reciprocity must hold, independent of whether T invariance is valid. If T invariance does not hold, unitarity restricts the form of possible time dependence of reciprocity ratios. copyright 1996 The American Physical Society

  1. THE EVOLUTION OF CANALIZATION AND THE BREAKING OF VON BAER'S LAWS: MODELING THE EVOLUTION OF DEVELOPMENT WITH EPISTASIS.

    Science.gov (United States)

    Rice, Sean H

    1998-06-01

    Evolution can change the developmental processes underlying a character without changing the average expression of the character itself. This sort of change must occur in both the evolution of canalization, in which a character becomes increasingly buffered against genetic or developmental variation, and in the phenomenon of closely related species that show similar adult phenotypes but different underlying developmental patterns. To study such phenomena, I develop a model that follows evolution on a surface representing adult phenotype as a function of underlying developmental characters. A contour on such a "phenotype landscape" is a set of states of developmental characters that produce the same adult phenotype. Epistasis induces curvature of this surface, and degree of canalization is represented by the slope along a contour. I first discuss the geometric properties of phenotype landscapes, relating epistasis to canalization. I then impose a fitness function on the phenotype and model evolution of developmental characters as a function of the fitness function and the local geometry of the surface. This model shows how canalization evolves as a population approaches an optimum phenotype. It further shows that under some circumstances, "decanalization" can occur, in which the expression of adult phenotype becomes increasingly sensitive to developmental variation. This process can cause very similar populations to diverge from one another developmentally even when their adult phenotypes experience identical selection regimes. © 1998 The Society for the Study of Evolution.

  2. Ancestral state reconstruction, rate heterogeneity, and the evolution of reptile viviparity.

    Science.gov (United States)

    King, Benedict; Lee, Michael S Y

    2015-05-01

    Virtually all models for reconstructing ancestral states for discrete characters make the crucial assumption that the trait of interest evolves at a uniform rate across the entire tree. However, this assumption is unlikely to hold in many situations, particularly as ancestral state reconstructions are being performed on increasingly large phylogenies. Here, we show how failure to account for such variable evolutionary rates can cause highly anomalous (and likely incorrect) results, while three methods that accommodate rate variability yield the opposite, more plausible, and more robust reconstructions. The random local clock method, implemented in BEAST, estimates the position and magnitude of rate changes on the tree; split BiSSE estimates separate rate parameters for pre-specified clades; and the hidden rates model partitions each character state into a number of rate categories. Simulations show the inadequacy of traditional models when characters evolve with both asymmetry (different rates of change between states within a character) and heterotachy (different rates of character evolution across different clades). The importance of accounting for rate heterogeneity in ancestral state reconstruction is highlighted empirically with a new analysis of the evolution of viviparity in squamate reptiles, which reveal a predominance of forward (oviparous-viviparous) transitions and very few reversals. © The Author(s) 2015. Published by Oxford University Press, on behalf of the Society of Systematic Biologists. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. The covariant-evolution-operator method in bound-state QED

    International Nuclear Information System (INIS)

    Lindgren, Ingvar; Salomonson, Sten; Aasen, Bjoern

    2004-01-01

    The methods of quantum-electrodynamical (QED) calculations on bound atomic systems are reviewed with emphasis on the newly developed covariant-evolution-operator method. The aim is to compare that method with other available methods and also to point out possibilities to combine that with standard many-body perturbation theory (MBPT) in order to perform accurate numerical QED calculations, including quasi-degeneracy, also for light elements, where the electron correlation is relatively strong. As a background, the time-independent many-body perturbation theory (MBPT) is briefly reviewed, particularly the method with extended model space. Time-dependent perturbation theory is discussed in some detail, introducing the time-evolution operator and the Gell-Mann-Low relation, generalized to an arbitrary model space. Three methods of treating the bound-state QED problem are discussed. The standard S-matrix formulation, which is restricted to a degenerate model space, is discussed only briefly. Two methods applicable also to the quasi-degenerate problem are treated in more detail, the two-times Green's-function and the covariant-evolution-operator techniques. The treatment is concentrated on the latter technique, which has been developed more recently and which has not been discussed in more detail before. A comparison of the two-times Green's-function and the covariant-evolution-operator techniques, which have great similarities, is performed. In the appendix a simple procedure is derived for expressing the evolution-operator diagrams of arbitrary order. The possibilities of merging QED in the covariant evolution-operator formulation with MBPT in a systematic way is indicated. With such a technique it might be feasible to perform accurate QED calculations also on light elements, which is presently not possible with the techniques available

  4. Evolution of Black-Box Models Based on Volterra Series

    Directory of Open Access Journals (Sweden)

    Daniel D. Silveira

    2015-01-01

    Full Text Available This paper presents a historical review of the many behavioral models actually used to model radio frequency power amplifiers and a new classification of these behavioral models. It also discusses the evolution of these models, from a single polynomial to multirate Volterra models, presenting equations and estimation methods. New trends in RF power amplifier behavioral modeling are suggested.

  5. Quantitative Modeling of Landscape Evolution, Treatise on Geomorphology

    NARCIS (Netherlands)

    Temme, A.J.A.M.; Schoorl, J.M.; Claessens, L.F.G.; Veldkamp, A.; Shroder, F.S.

    2013-01-01

    This chapter reviews quantitative modeling of landscape evolution – which means that not just model studies but also modeling concepts are discussed. Quantitative modeling is contrasted with conceptual or physical modeling, and four categories of model studies are presented. Procedural studies focus

  6. A model of the microphysical evolution of a cloud

    International Nuclear Information System (INIS)

    Zinn, J.

    1994-01-01

    The earth's weather and climate are influenced strongly by phenomena associated with clouds. Therefore, a general circulation model (GCM) that models the evolution of weather and climate must include an accurate physical model of the clouds. This paper describes efforts to develop a suitable cloud model. It concentrates on the microphysical processes that determine the evolution of droplet and ice crystal size distributions, precipitation rates, total and condensed water content, and radiative extinction coefficients

  7. Contemporary Ecological Interactions Improve Models of Past Trait Evolution.

    Science.gov (United States)

    Hutchinson, Matthew C; Gaiarsa, Marília P; Stouffer, Daniel B

    2018-02-20

    Despite the fact that natural selection underlies both traits and interactions, evolutionary models often neglect that ecological interactions may, and in many cases do, influence the evolution of traits. Here, we explore the interdependence of ecological interactions and functional traits in the pollination associations of hawkmoths and flowering plants. Specifically, we develop an adaptation of the Ornstein-Uhlenbeck model of trait evolution that allows us to study the influence of plant corolla depth and observed hawkmoth-plant interactions on the evolution of hawkmoth proboscis length. Across diverse modelling scenarios, we find that the inclusion of contemporary interactions can provide a better description of trait evolution than the null expectation. Moreover, we show that the pollination interactions provide more-likely models of hawkmoth trait evolution when interactions are considered at increasingly finescale groups of hawkmoths. Finally, we demonstrate how the results of best-fit modelling approaches can implicitly support the association between interactions and trait evolution that our method explicitly examines. In showing that contemporary interactions can provide insight into the historical evolution of hawkmoth proboscis length, we demonstrate the clear utility of incorporating additional ecological information to models designed to study past trait evolution.

  8. Modeling Temporal Evolution and Multiscale Structure in Networks

    DEFF Research Database (Denmark)

    Herlau, Tue; Mørup, Morten; Schmidt, Mikkel Nørgaard

    2013-01-01

    Many real-world networks exhibit both temporal evolution and multiscale structure. We propose a model for temporally correlated multifurcating hierarchies in complex networks which jointly capture both effects. We use the Gibbs fragmentation tree as prior over multifurcating trees and a change......-point model to account for the temporal evolution of each vertex. We demonstrate that our model is able to infer time-varying multiscale structure in synthetic as well as three real world time-evolving complex networks. Our modeling of the temporal evolution of hierarchies brings new insights...

  9. State Space Modeling Using SAS

    Directory of Open Access Journals (Sweden)

    Rajesh Selukar

    2011-05-01

    Full Text Available This article provides a brief introduction to the state space modeling capabilities in SAS, a well-known statistical software system. SAS provides state space modeling in a few different settings. SAS/ETS, the econometric and time series analysis module of the SAS system, contains many procedures that use state space models to analyze univariate and multivariate time series data. In addition, SAS/IML, an interactive matrix language in the SAS system, provides Kalman filtering and smoothing routines for stationary and nonstationary state space models. SAS/IML also provides support for linear algebra and nonlinear function optimization, which makes it a convenient environment for general-purpose state space modeling.

  10. Modelling of Damage Evolution in Braided Composites: Recent Developments

    Science.gov (United States)

    Wang, Chen; Roy, Anish; Silberschmidt, Vadim V.; Chen, Zhong

    2017-12-01

    Composites reinforced with woven or braided textiles exhibit high structural stability and excellent damage tolerance thanks to yarn interlacing. With their high stiffness-to-weight and strength-to-weight ratios, braided composites are attractive for aerospace and automotive components as well as sports protective equipment. In these potential applications, components are typically subjected to multi-directional static, impact and fatigue loadings. To enhance material analysis and design for such applications, understanding mechanical behaviour of braided composites and development of predictive capabilities becomes crucial. Significant progress has been made in recent years in development of new modelling techniques allowing elucidation of static and dynamic responses of braided composites. However, because of their unique interlacing geometric structure and complicated failure modes, prediction of damage initiation and its evolution in components is still a challenge. Therefore, a comprehensive literature analysis is presented in this work focused on a review of the state-of-the-art progressive damage analysis of braided composites with finite-element simulations. Recently models employed in the studies on mechanical behaviour, impact response and fatigue analyses of braided composites are presented systematically. This review highlights the importance, advantages and limitations of as-applied failure criteria and damage evolution laws for yarns and composite unit cells. In addition, this work provides a good reference for future research on FE simulations of braided composites.

  11. Evolution of perturbations in distinct classes of canonical scalar field models of dark energy

    International Nuclear Information System (INIS)

    Jassal, H. K.

    2010-01-01

    Dark energy must cluster in order to be consistent with the equivalence principle. The background evolution can be effectively modeled by either a scalar field or by a barotropic fluid. The fluid model can be used to emulate perturbations in a scalar field model of dark energy, though this model breaks down at large scales. In this paper we study evolution of dark energy perturbations in canonical scalar field models: the classes of thawing and freezing models. The dark energy equation of state evolves differently in these classes. In freezing models, the equation of state deviates from that of a cosmological constant at early times. For thawing models, the dark energy equation of state remains near that of the cosmological constant at early times and begins to deviate from it only at late times. Since the dark energy equation of state evolves differently in these classes, the dark energy perturbations too evolve differently. In freezing models, since the equation of state deviates from that of a cosmological constant at early times, there is a significant difference in evolution of matter perturbations from those in the cosmological constant model. In comparison, matter perturbations in thawing models differ from the cosmological constant only at late times. This difference provides an additional handle to distinguish between these classes of models and this difference should manifest itself in the integrated Sachs-Wolfe effect.

  12. Existence results for impulsive evolution differential equations with state-dependent delay

    OpenAIRE

    Eduardo Hernandez M.; Rathinasamy Sakthivel; Sueli Tanaka Aki

    2008-01-01

    We study the existence of mild solution for impulsive evolution abstract differential equations with state-dependent delay. A concrete application to partial delayed differential equations is considered.

  13. Modelling the evolution and consequences of mate choice

    OpenAIRE

    Tazzyman, S. J.

    2010-01-01

    This thesis considers the evolution and the consequences of mate choice across a variety of taxa, using game theoretic, population genetic, and quantitative genetic modelling techniques. Part I is about the evolution of mate choice. In chapter 2, a population genetic model shows that mate choice is even beneficial in self-fertilising species such as Saccharomyces yeast. In chapter 3, a game theoretic model shows that female choice will be strongly dependent upon whether the benefi...

  14. Computer modelling as a tool for understanding language evolution

    NARCIS (Netherlands)

    de Boer, Bart; Gontier, N; VanBendegem, JP; Aerts, D

    2006-01-01

    This paper describes the uses of computer models in studying the evolution of language. Language is a complex dynamic system that can be studied at the level of the individual and at the level of the population. Much of the dynamics of language evolution and language change occur because of the

  15. Modeling Software Evolution using Algebraic Graph Rewriting

    NARCIS (Netherlands)

    Ciraci, Selim; van den Broek, Pim

    We show how evolution requests can be formalized using algebraic graph rewriting. In particular, we present a way to convert the UML class diagrams to colored graphs. Since changes in software may effect the relation between the methods of classes, our colored graph representation also employs the

  16. Thermal evolution of the Schwinger model with matrix product operators

    International Nuclear Information System (INIS)

    Banuls, M.C.; Cirac, J.I.; Cichy, K.; Jansen, K.; Saito, H.

    2015-10-01

    We demonstrate the suitability of tensor network techniques for describing the thermal evolution of lattice gauge theories. As a benchmark case, we have studied the temperature dependence of the chiral condensate in the Schwinger model, using matrix product operators to approximate the thermal equilibrium states for finite system sizes with non-zero lattice spacings. We show how these techniques allow for reliable extrapolations in bond dimension, step width, system size and lattice spacing, and for a systematic estimation and control of all error sources involved in the calculation. The reached values of the lattice spacing are small enough to capture the most challenging region of high temperatures and the final results are consistent with the analytical prediction by Sachs and Wipf over a broad temperature range.

  17. Substructure evolution of Zircaloy-4 during creep and implications for the Modified Jogged-Screw model

    Energy Technology Data Exchange (ETDEWEB)

    Morrow, B.M., E-mail: morrow@lanl.gov [The Ohio State University, 2041 College Rd., 477 Watts Hall, Columbus, OH 43210 (United States); Los Alamos National Laboratory, P.O. Box 1663, MS G755, Los Alamos, NM 87545 (United States); Kozar, R.W.; Anderson, K.R. [Bettis Laboratory, Bechtel Marine Propulsion Corp., West Mifflin, PA 15122 (United States); Mills, M.J., E-mail: millsmj@mse.osu.edu [The Ohio State University, 2041 College Rd., 477 Watts Hall, Columbus, OH 43210 (United States)

    2016-05-17

    Several specimens of Zircaloy-4 were creep tested at a single stress-temperature condition, and interrupted at different accumulated strain levels. Substructural observations were performed using bright field scanning transmission electron microscopy (BF STEM). The dislocation substructure was characterized to ascertain how creep strain evolution impacts the Modified Jogged-Screw (MJS) model, which has previously been utilized to predict steady-state strain rates in Zircaloy-4. Special attention was paid to the evolution of individual model parameters with increasing strain. Results of model parameter measurements are reported and discussed, along with possible extensions to the MJS model.

  18. Learning and evolution in games and oligopoly models

    NARCIS (Netherlands)

    Possajennikov, A.

    2000-01-01

    Dynamic models of adjustment, as well as static models of equilibrium, are important to understand economic reality. This thesis considers such dynamic models applied to economic games. The models can broadly be divided into two categories: learning and evolution. This thesis analyzes reinforcement

  19. Modelling the secular evolution of migrating planet pairs

    Science.gov (United States)

    Michtchenko, T. A.; Rodríguez, A.

    2011-08-01

    The subject of this paper is the secular behaviour of a pair of planets evolving under dissipative forces. In particular, we investigate the case when dissipative forces affect the planetary semimajor axes and the planets move inwards/outwards the central star, in a process known as planet migration. To perform this investigation, we introduce fundamental concepts of conservative and dissipative dynamics of the three-body problem. Based on these concepts, we develop a qualitative model of the secular evolution of the migrating planetary pair. Our approach is based on the analysis of the energy and the orbital angular momentum exchange between the two-planet system and an external medium; thus no specific kind of dissipative forces is invoked. We show that, under the assumption that dissipation is weak and slow, the evolutionary routes of the migrating planets are traced by the Mode I and Mode II stationary solutions of the conservative secular problem. The ultimate convergence and the evolution of the system along one of these secular modes of motion are determined uniquely by the condition that the dissipation rate is sufficiently smaller than the proper secular frequency of the system. We show that it is possible to reassemble the starting configurations and the migration history of the systems on the basis of their final states and consequently to constrain the parameters of the physical processes involved.

  20. An analytically solvable model for rapid evolution of modular structure.

    Directory of Open Access Journals (Sweden)

    Nadav Kashtan

    2009-04-01

    Full Text Available Biological systems often display modularity, in the sense that they can be decomposed into nearly independent subsystems. Recent studies have suggested that modular structure can spontaneously emerge if goals (environments change over time, such that each new goal shares the same set of sub-problems with previous goals. Such modularly varying goals can also dramatically speed up evolution, relative to evolution under a constant goal. These studies were based on simulations of model systems, such as logic circuits and RNA structure, which are generally not easy to treat analytically. We present, here, a simple model for evolution under modularly varying goals that can be solved analytically. This model helps to understand some of the fundamental mechanisms that lead to rapid emergence of modular structure under modularly varying goals. In particular, the model suggests a mechanism for the dramatic speedup in evolution observed under such temporally varying goals.

  1. Time evolution of the Wigner function in the entangled-state representation

    International Nuclear Information System (INIS)

    Fan Hongyi

    2002-01-01

    For quantum-mechanical entangled states we introduce the entangled Wigner operator in the entangled-state representation. We derive the time evolution equation of the entangled Wigner operator . The trace product rule for entangled Wigner functions is also obtained

  2. Dynamic Evolution Model Based on Social Network Services

    Science.gov (United States)

    Xiong, Xi; Gou, Zhi-Jian; Zhang, Shi-Bin; Zhao, Wen

    2013-11-01

    Based on the analysis of evolutionary characteristics of public opinion in social networking services (SNS), in the paper we propose a dynamic evolution model, in which opinions are coupled with topology. This model shows the clustering phenomenon of opinions in dynamic network evolution. The simulation results show that the model can fit the data from a social network site. The dynamic evolution of networks accelerates the opinion, separation and aggregation. The scale and the number of clusters are influenced by confidence limit and rewiring probability. Dynamic changes of the topology reduce the number of isolated nodes, while the increased confidence limit allows nodes to communicate more sufficiently. The two effects make the distribution of opinion more neutral. The dynamic evolution of networks generates central clusters with high connectivity and high betweenness, which make it difficult to control public opinions in SNS.

  3. Development of a numerical 2-dimensional beach evolution model

    DEFF Research Database (Denmark)

    Baykal, Cüneyt

    2014-01-01

    This paper presents the description of a 2-dimensional numerical model constructed for the simulation of beach evolution under the action of wind waves only over the arbitrary land and sea topographies around existing coastal structures and formations. The developed beach evolution numerical model...... is composed of 4 submodels: a nearshore spectral wave transformation model based on an energy balance equation including random wave breaking and diffraction terms to compute the nearshore wave characteristics, a nearshore wave-induced circulation model based on the nonlinear shallow water equations...... to compute the nearshore depth-averaged wave-induced current velocities and mean water level changes, a sediment transport model to compute the local total sediment transport rates occurring under the action of wind waves, and a bottom evolution model to compute the bed level changes in time based...

  4. Equations of State: Gateway to Planetary Origin and Evolution (Invited)

    Science.gov (United States)

    Melosh, J.

    2013-12-01

    Research over the past decades has shown that collisions between solid bodies govern many crucial phases of planetary origin and evolution. The accretion of the terrestrial planets was punctuated by planetary-scale impacts that generated deep magma oceans, ejected primary atmospheres and probably created the moons of Earth and Pluto. Several extrasolar planetary systems are filled with silicate vapor and condensed 'tektites', probably attesting to recent giant collisions. Even now, long after the solar system settled down from its violent birth, a large asteroid impact wiped out the dinosaurs, while other impacts may have played a role in the origin of life on Earth and perhaps Mars, while maintaining a steady exchange of small meteorites between the terrestrial planets and our moon. Most of these events are beyond the scale at which experiments are possible, so that our main research tool is computer simulation, constrained by the laws of physics and the behavior of materials during high-speed impact. Typical solar system impact velocities range from a few km/s in the outer solar system to 10s of km/s in the inner system. Extrasolar planetary systems expand that range to 100s of km/sec typical of the tightly clustered planetary systems now observed. Although computer codes themselves are currently reaching a high degree of sophistication, we still rely on experimental studies to determine the Equations of State (EoS) of materials critical for the correct simulation of impact processes. The recent expansion of the range of pressures available for study, from a few 100 GPa accessible with light gas guns up to a few TPa from current high energy accelerators now opens experimental access to the full velocity range of interest in our solar system. The results are a surprise: several groups in both the USA and Japan have found that silicates and even iron melt and vaporize much more easily in an impact than previously anticipated. The importance of these findings is

  5. Computer models of vocal tract evolution: an overview and critique

    NARCIS (Netherlands)

    de Boer, B.; Fitch, W. T.

    2010-01-01

    Human speech has been investigated with computer models since the invention of digital computers, and models of the evolution of speech first appeared in the late 1960s and early 1970s. Speech science and computer models have a long shared history because speech is a physical signal and can be

  6. Evolution of the Moon: the 1974 model

    International Nuclear Information System (INIS)

    Schmitt, H.H.

    1975-01-01

    The interpretive evolution of the Moon can be divided now into seven major stages beginning sometime near the end of the formation of the solar system. These stages and their approximate durations are as follows: 1. The Beginning - 4.6 billion years ago. 2. The Melted Shell-4.6-4.4 billion years ago. 3. The Cratered Highlands -4.4-4.1 billion years ago. 4. The Large Basins-4.1-3.9 billion years ago. 5. The Light-Coloured Plains-3.9-3.8 billion years ago 6. The Basaltic Maria -3.8-3.0 billion years ago. 7. The Quiet Crust-3.0 billion years ago to the present. The Apollo and Luna explorations that permit the study of these stages of evolution have each contributed in progressive and significant ways. Through them the early differentiation of the Earth, the nature of the Earth's protocrust, the influence of the formation of large impact basins in that crust, the effects of early partial melting of the protomantle and possibly the earliest stages of the breakup of the protocrust into continents and ocean basins can now be looked at with new insight. (Auth.)

  7. Jump diffusion models and the evolution of financial prices

    International Nuclear Information System (INIS)

    Figueiredo, Annibal; Castro, Marcio T. de; Silva, Sergio da; Gleria, Iram

    2011-01-01

    We analyze a stochastic model to describe the evolution of financial prices. We consider the stochastic term as a sum of the Wiener noise and a jump process. We point to the effects of the jumps on the return time evolution, a central concern of the econophysics literature. The presence of jumps suggests that the process can be described by an infinitely divisible characteristic function belonging to the De Finetti class. We then extend the De Finetti functions to a generalized nonlinear model and show the model to be capable of explaining return behavior. -- Highlights: → We analyze a stochastic model to describe the evolution of financial prices. → The stochastic term is considered as a sum of the Wiener noise and a jump process. → The process can be described by an infinitely divisible characteristic function belonging to the De Finetti class. → We extend the De Finetti functions to a generalized nonlinear model.

  8. A last updating evolution model for online social networks

    Science.gov (United States)

    Bu, Zhan; Xia, Zhengyou; Wang, Jiandong; Zhang, Chengcui

    2013-05-01

    As information technology has advanced, people are turning to electronic media more frequently for communication, and social relationships are increasingly found on online channels. However, there is very limited knowledge about the actual evolution of the online social networks. In this paper, we propose and study a novel evolution network model with the new concept of “last updating time”, which exists in many real-life online social networks. The last updating evolution network model can maintain the robustness of scale-free networks and can improve the network reliance against intentional attacks. What is more, we also found that it has the “small-world effect”, which is the inherent property of most social networks. Simulation experiment based on this model show that the results and the real-life data are consistent, which means that our model is valid.

  9. Hydrogeological modelling as a tool for understanding rockslides evolution

    Science.gov (United States)

    Crosta, Giovanni B.; De Caro, Mattia; Frattini, Paolo; Volpi, Giorgio

    2015-04-01

    Several case studies of large rockslides have been presented in the literature showing dependence of displacement rate on seasonal and annual changes of external factors (e.g. rainfall, snowmelt, temperature oscillations) or on human actions (e.g. impounding of landslide toe by artificial lakes, toe excavation). The study of rockslide triggering can focus on either the initial failure or the successive reactivations driven by either meteo-climatic events or other perturbations (e.g. seismic, anthropic). A correlation between groundwater level oscillations and slope movements has been observed at many different sites and in very different materials and slope settings. This seasonal dynamic behavior generally shows a delay between perturbation (e.g., groundwater recharge and increase in water table level) and system reaction (e.g., increase in displacement rate). For this reason, groundwater modeling offers the means for assessing the oscillation of groundwater level which is a major input in rockslide and deep-seated gravitational slope deformation modelling, and that could explain both the initial failure event as well the successive reactivation or the continuous slow motion. Using a finite element software (FEFLOW, WASY GmbH) we developed 2D saturated/unsaturated and steady-state/transient groundwater flow models for two case studies for which a suitable dataset is available: the Vajont rockslide (from 1960 to October 9th 1963) and the Mt. de La Saxe rockslide (2009-2012, Aosta valley; Italian Western Alps). The transient models were implemented starting from hydraulic head distributions simulated in the previous steady-state models to investigate the groundwater fluctuation within the two chosen times interval (Vajont: 1960-1963 ; La Saxe: 2009-2012). Time series of infiltration resulting from precipitation, temperature, snowmelt data (La Saxe rockslide) and reservoir level (Vajont rockslide) were applied to the models. The assumptions made during the

  10. Application of the evolution theory in modelling of innovation diffusion

    Directory of Open Access Journals (Sweden)

    Krstić Milan

    2016-01-01

    Full Text Available The theory of evolution has found numerous analogies and applications in other scientific disciplines apart from biology. In that sense, today the so-called 'memetic-evolution' has been widely accepted. Memes represent a complex adaptable system, where one 'meme' represents an evolutional cultural element, i.e. the smallest unit of information which can be identified and used in order to explain the evolution process. Among others, the field of innovations has proved itself to be a suitable area where the theory of evolution can also be successfully applied. In this work the authors have started from the assumption that it is also possible to apply the theory of evolution in the modelling of the process of innovation diffusion. Based on the conducted theoretical research, the authors conclude that the process of innovation diffusion in the interpretation of a 'meme' is actually the process of imitation of the 'meme' of innovation. Since during the process of their replication certain 'memes' show a bigger success compared to others, that eventually leads to their natural selection. For the survival of innovation 'memes', their manifestations are of key importance in the sense of their longevity, fruitfulness and faithful replicating. The results of the conducted research have categorically confirmed the assumption of the possibility of application of the evolution theory with the innovation diffusion with the help of innovation 'memes', which opens up the perspectives for some new researches on the subject.

  11. Modeling the summertime evolution of sea-ice melt ponds

    DEFF Research Database (Denmark)

    Lüthje, Mikael; Feltham, D.L.; Taylor, P.D.

    2006-01-01

    We present a mathematical model describing the summer melting of sea ice. We simulate the evolution of melt ponds and determine area coverage and total surface ablation. The model predictions are tested for sensitivity to the melt rate of unponded ice, enhanced melt rate beneath the melt ponds...

  12. Optimality models in the age of experimental evolution and genomics.

    Science.gov (United States)

    Bull, J J; Wang, I-N

    2010-09-01

    Optimality models have been used to predict evolution of many properties of organisms. They typically neglect genetic details, whether by necessity or design. This omission is a common source of criticism, and although this limitation of optimality is widely acknowledged, it has mostly been defended rather than evaluated for its impact. Experimental adaptation of model organisms provides a new arena for testing optimality models and for simultaneously integrating genetics. First, an experimental context with a well-researched organism allows dissection of the evolutionary process to identify causes of model failure--whether the model is wrong about genetics or selection. Second, optimality models provide a meaningful context for the process and mechanics of evolution, and thus may be used to elicit realistic genetic bases of adaptation--an especially useful augmentation to well-researched genetic systems. A few studies of microbes have begun to pioneer this new direction. Incompatibility between the assumed and actual genetics has been demonstrated to be the cause of model failure in some cases. More interestingly, evolution at the phenotypic level has sometimes matched prediction even though the adaptive mutations defy mechanisms established by decades of classic genetic studies. Integration of experimental evolutionary tests with genetics heralds a new wave for optimality models and their extensions that does not merely emphasize the forces driving evolution.

  13. Dynamics of symmetry breaking during quantum real-time evolution in a minimal model system.

    Science.gov (United States)

    Heyl, Markus; Vojta, Matthias

    2014-10-31

    One necessary criterion for the thermalization of a nonequilibrium quantum many-particle system is ergodicity. It is, however, not sufficient in cases where the asymptotic long-time state lies in a symmetry-broken phase but the initial state of nonequilibrium time evolution is fully symmetric with respect to this symmetry. In equilibrium, one particular symmetry-broken state is chosen as a result of an infinitesimal symmetry-breaking perturbation. From a dynamical point of view the question is: Can such an infinitesimal perturbation be sufficient for the system to establish a nonvanishing order during quantum real-time evolution? We study this question analytically for a minimal model system that can be associated with symmetry breaking, the ferromagnetic Kondo model. We show that after a quantum quench from a completely symmetric state the system is able to break its symmetry dynamically and discuss how these features can be observed experimentally.

  14. Modeling the secular evolution of migrating planet pairs

    Science.gov (United States)

    Michtchenko, T. A.; Rodríguez, A.

    2011-10-01

    The secular regime of motion of multi-planetary systems is universal; in contrast with the 'accidental' resonant motion, characteristic only for specific configurations of the planets, secular motion is present everywhere in phase space, even inside the resonant region. The secular behavior of a pair of planets evolving under dissipative forces is the principal subject of this study, particularly, the case when the dissipative forces affect the planetary semi-major axes and the planets move inward/outward the central star, the process known as planet migration. Based on the fundamental concepts of conservative and dissipative dynamics of the three-body problem, we develop a qualitative model of the secular evolution of the migrating planetary pair. Our approach is based on analysis of the energy and the orbital angular momentum exchange between the two-planet system and an external medium; thus no specific kind of dissipative forces is invoked. We show that, under assumption that dissipation is weak and slow, the evolutionary routes of the migrating planets are traced by the Mode I and Mode II stationary solutions of the conservative secular problem. The ultimate convergence and the evolution of the system along one of these secular modes of motion is determined uniquely by the condition that the dissipation rate is sufficiently smaller than the proper secular frequency of the system. We show that it is possible to reassemble the starting configurations and migration history of the systems on the basis of their final states and consequently to constrain the parameters of the physical processes involved.

  15. Fluorine in the solar neighborhood: Chemical evolution models

    Science.gov (United States)

    Spitoni, E.; Matteucci, F.; Jönsson, H.; Ryde, N.; Romano, D.

    2018-04-01

    Context. In light of new observational data related to fluorine abundances in solar neighborhood stars, we present chemical evolution models testing various fluorine nucleosynthesis prescriptions with the aim to best fit those new data. Aim. We consider chemical evolution models in the solar neighborhood testing various nucleosynthesis prescriptions for fluorine production with the aim of reproducing the observed abundance ratios [F/O] versus [O/H] and [F/Fe] versus [Fe/H]. We study in detail the effects of various stellar yields on fluorine production. Methods: We adopted two chemical evolution models: the classical two-infall model, which follows the chemical evolution of halo-thick disk and thin disk phases; and the one-infall model, which is designed only for thin disk evolution. We tested the effects on the predicted fluorine abundance ratios of various nucleosynthesis yield sources, that is, asymptotic giant branch (AGB) stars, Wolf-Rayet (W-R) stars, Type II and Type Ia supernovae, and novae. Results: The fluorine production is dominated by AGB stars but the W-R stars are required to reproduce the trend of the observed data in the solar neighborhood with our chemical evolution models. In particular, the best model both for the two-infall and one-infall cases requires an increase by a factor of 2 of the W-R yields. We also show that the novae, even if their yields are still uncertain, could help to better reproduce the secondary behavior of F in the [F/O] versus [O/H] relation. Conclusions: The inclusion of the fluorine production by W-R stars seems to be essential to reproduce the new observed ratio [F/O] versus [O/H] in the solar neighborhood. Moreover, the inclusion of novae helps to reproduce the observed fluorine secondary behavior substantially.

  16. Rethinking the evolution of specialization: A model for the evolution of phenotypic heterogeneity.

    Science.gov (United States)

    Rubin, Ilan N; Doebeli, Michael

    2017-12-21

    Phenotypic heterogeneity refers to genetically identical individuals that express different phenotypes, even when in the same environment. Traditionally, "bet-hedging" in fluctuating environments is offered as the explanation for the evolution of phenotypic heterogeneity. However, there are an increasing number of examples of microbial populations that display phenotypic heterogeneity in stable environments. Here we present an evolutionary model of phenotypic heterogeneity of microbial metabolism and a resultant theory for the evolution of phenotypic versus genetic specialization. We use two-dimensional adaptive dynamics to track the evolution of the population phenotype distribution of the expression of two metabolic processes with a concave trade-off. Rather than assume a Gaussian phenotype distribution, we use a Beta distribution that is capable of describing genotypes that manifest as individuals with two distinct phenotypes. Doing so, we find that environmental variation is not a necessary condition for the evolution of phenotypic heterogeneity, which can evolve as a form of specialization in a stable environment. There are two competing pressures driving the evolution of specialization: directional selection toward the evolution of phenotypic heterogeneity and disruptive selection toward genetically determined specialists. Because of the lack of a singular point in the two-dimensional adaptive dynamics and the fact that directional selection is a first order process, while disruptive selection is of second order, the evolution of phenotypic heterogeneity dominates and often precludes speciation. We find that branching, and therefore genetic specialization, occurs mainly under two conditions: the presence of a cost to maintaining a high phenotypic variance or when the effect of mutations is large. A cost to high phenotypic variance dampens the strength of selection toward phenotypic heterogeneity and, when sufficiently large, introduces a singular point into

  17. The next generation of galaxy evolution models: A symbiosis of stellar populations and chemical abundances

    Science.gov (United States)

    Kotulla, Ralf

    2012-10-01

    Over its lifespan Hubble has invested significant effort into detailed observations of galaxies both in the local and distant universe. To extract the physical information from the observed {spectro-}photometry requires detailed and accurate models. Stellar population synthesis models are frequently used to obtain stellar masses, star formation rate, galaxy ages and star formation histories. Chemical evolution models offer another valuable and complementary approach to gain insight into many of the same aspects, yet these two methods have rarely been used in combination.Our proposed next generation of galaxy evolution models will help us improve our understanding of how galaxies form and evolve. Building on GALEV evolutionary synthesis models we incorporate state-of-the-art input physics for stellar evolution of binaries and rotating stars as well as new spectral libraries well matched to the modern observational capabilities. Our improved chemical evolution model allows us to self-consistently trace abundances of individual elements, fully accounting for the increasing initial abundances of successive stellar generations. GALEV will support variable Initial Mass Functions {IMF}, enabling us to test recent observational findings of a non-universal IMF by predicting chemical properties and integrated spectra in an integrated and consistent manner.HST is the perfect instrument for testing this approach. Its wide wavelength coverage from UV to NIR enables precise SED fitting, and with its spatial resolution we can compare the inferred chemical evolution to studies of star clusters and resolved stellar populations in nearby galaxies.

  18. Continuous "in vitro" Evolution of a Ribozyme Ligase: A Model Experiment for the Evolution of a Biomolecule

    Science.gov (United States)

    Ledbetter, Michael P.; Hwang, Tony W.; Stovall, Gwendolyn M.; Ellington, Andrew D.

    2013-01-01

    Evolution is a defining criterion of life and is central to understanding biological systems. However, the timescale of evolutionary shifts in phenotype limits most classroom evolution experiments to simple probability simulations. "In vitro" directed evolution (IVDE) frequently serves as a model system for the study of Darwinian…

  19. Applications of a composite model of microstructural evolution

    International Nuclear Information System (INIS)

    Stoller, R.E.

    1986-01-01

    Near-term fusion reactors will have to be designed using radiation effects data from experiments conducted in fast fission reactors. These fast reactors generate atomic displacements at a rate similar to that expected in a DT fusion reactor first wall. However, the transmutant helium production in an austenitic stainless steel first wall will exceed that in fast reactor fuel cladding by about a factor of 30. Hence, the use of the fast reactor data will involve some extrapolation. A major goal of this work is to develop theoretical models of microstructural evolution to aid in this extrapolation. In the present work a detailed rate-theory-based model of microstructural evolution under fast neutron irradiation has been developed. The prominent new aspect of this model is a treatment of dislocation evolution in which Frank faulted loops nucleate, grow and unfault to provide a source for network dislocations while the dislocation network can be simultaneously annihilated by a climb/glide process. The predictions of this model compare very favorably with the observed dose and temperature dependence of these key microstructural features over a broad range. In addition, this new description of dislocation evolution has been coupled with a previously developed model of cavity evolution and good agreement has been obtained between the predictions of the composite model and fast reactor swelling data. The results from the composite model also reveal that the various components of the irradiation-induced microstructure evolve in a highly coupled manner. The predictions of the composite model are more sensitive to parametric variations than more simple models. Hence, its value as a tool in data analysis and extrapolation is enhanced

  20. Absorbing multicultural states in the Axelrod model

    Science.gov (United States)

    Vazquez, Federico; Redner, Sidney

    2005-03-01

    We determine the ultimate fate of a limit of the Axelrod model that consists of a population of leftists, centrists, and rightists. In an elemental interaction between agents, a centrist and a leftist can both become centrists or both become leftists with equal rates (similarly for a centrist and a rightist), but leftists and rightists do not interact. This interaction is applied repeatedly until the system can no longer evolve. The constraint between extremists can lead to a frustrated final state where the system consists of only leftists and rightists. In the mean field limit, we can view the evolution of the system as the motion of a random walk in the 3-dimensional space whose coordinates correspond to the density of each species. We find the exact final state probabilities and the time to reach consensus by solving for the first-passage probability of the random walk to the corresponding absorbing boundaries. The extension to a larger number of states will be discussed. This approach is a first step towards the analytic solution of Axelrod-like models.

  1. Modelling rate distributions using character compatibility: implications for morphological evolution among fossil invertebrates.

    Science.gov (United States)

    Wagner, Peter J

    2012-02-23

    Rate distributions are important considerations when testing hypotheses about morphological evolution or phylogeny. They also have implications about general processes underlying character evolution. Molecular systematists often assume that rates are Poisson processes with gamma distributions. However, morphological change is the product of multiple probabilistic processes and should theoretically be affected by hierarchical integration of characters. Both factors predict lognormal rate distributions. Here, a simple inverse modelling approach assesses the best single-rate, gamma and lognormal models given observed character compatibility for 115 invertebrate groups. Tests reject the single-rate model for nearly all cases. Moreover, the lognormal outperforms the gamma for character change rates and (especially) state derivation rates. The latter in particular is consistent with integration affecting morphological character evolution.

  2. Modeling on Fe-Cr microstructure: evolution with Cr content

    International Nuclear Information System (INIS)

    Diaz Arroyo, D.; Perlado, J.M.; Hernandez-Mayoral, M.; Caturla, M.J.; Victoria, M.

    2007-01-01

    Full text of publication follows: The minimum energy configuration of interstitials in the Fe-Cr system, which is the base for the low activation steels being developed in the European fusion reactor materials community, is determined by magnetism. Magnetism plays also a role in the atomic configurations found with increasing Cr content. Results will be presented from a program in which the microstructure evolution produced after heavy ion irradiation in the range from room temperature to 80 K is studied as a function of the Cr content in alloys produced under well controlled conditions, i.e. from high purity elements and with adequate heat treatment. It is expected that these measurements will serve as matrix for model validation. The first step in such modeling sequence is being performed by modeling the evolution of displacement cascades in Fe using the Dudarev -Derlet and Mendeleev potentials for Fe and the Caro potential for Fe-Cr. It is of particular interest to study the evolution of high-energy cascades, where an attempt will be made to clarify the role of the evolution of sub-cascades. Kinetic Monte Carlo (kMC) techniques will be used then to simulate the defect evolution. A new parallel kMC code is being implemented for this purpose. (authors)

  3. Evolution of a minimal parallel programming model

    International Nuclear Information System (INIS)

    Lusk, Ewing; Butler, Ralph; Pieper, Steven C.

    2017-01-01

    Here, we take a historical approach to our presentation of self-scheduled task parallelism, a programming model with its origins in early irregular and nondeterministic computations encountered in automated theorem proving and logic programming. We show how an extremely simple task model has evolved into a system, asynchronous dynamic load balancing (ADLB), and a scalable implementation capable of supporting sophisticated applications on today’s (and tomorrow’s) largest supercomputers; and we illustrate the use of ADLB with a Green’s function Monte Carlo application, a modern, mature nuclear physics code in production use. Our lesson is that by surrendering a certain amount of generality and thus applicability, a minimal programming model (in terms of its basic concepts and the size of its application programmer interface) can achieve extreme scalability without introducing complexity.

  4. Loess studies in central United States: Evolution of concepts

    Science.gov (United States)

    Follmer, L.R.

    1996-01-01

    Few words in the realm of earth science have caused more debate than "loess". It is a common term that was first used as a name of a silt deposit before it was defined in a scientific sense. Because this "loose" deposit is easily distinguished from other more coherent deposits, it was recognized as a matter of practical concern and later became the object of much scientific scrutiny. Loess was first recognized along the Rhine Valley in Germany in the 1830s and was first noted in the United States in 1846 along the lower Mississippi River where it later became the center of attention. The use of the name eventually spread around the world, but its use has not been consistently applied. Over the years some interpretations and stratigraphic correlations have been validated, but others have been hotly contested on conceptual grounds and semantic issues. The concept of loess evolved into a complex issue as loess and loess-like deposits were discovered in different parts of the US. The evolution of concepts in the central US developed in four indefinite stages: the eras of (1) discovery and development of hypotheses, (2) conditional acceptance of the eolian origin of loess, (3) "bandwagon" popularity of loess research, and (4) analytical inquiry on the nature of loess. Toward the end of the first era around 1900, the popular opinion on the meaning of the term loess shifted from a lithological sense of loose silt to a lithogenetic sense of eolian silt. However, the dual use of the term fostered a lingering skepticism during the second era that ended in 1944 with an explosion of interest that lasted for more than a decade. In 1944, R.J. Russell proposed and H.N. Fisk defended a new non-eolian, property-based, concept of loess. The eolian advocates reacted with surprise and enthusiasm. Each side used constrained arguments to show their view of the problem, but did not examine the fundamental problem, which was not in the proofs of their hypothesis, but in the definition of

  5. Optimality models in the age of experimental evolution and genomics

    OpenAIRE

    Bull, J. J.; Wang, I.-N.

    2010-01-01

    Optimality models have been used to predict evolution of many properties of organisms. They typically neglect genetic details, whether by necessity or design. This omission is a common source of criticism, and although this limitation of optimality is widely acknowledged, it has mostly been defended rather than evaluated for its impact. Experimental adaptation of model organisms provides a new arena for testing optimality models and for simultaneously integrating genetics. First, an experimen...

  6. Real time evolution at finite temperatures with operator space matrix product states

    International Nuclear Information System (INIS)

    Pižorn, Iztok; Troyer, Matthias; Eisler, Viktor; Andergassen, Sabine

    2014-01-01

    We propose a method to simulate the real time evolution of one-dimensional quantum many-body systems at finite temperature by expressing both the density matrices and the observables as matrix product states. This allows the calculation of expectation values and correlation functions as scalar products in operator space. The simulations of density matrices in inverse temperature and the local operators in the Heisenberg picture are independent and result in a grid of expectation values for all intermediate temperatures and times. Simulations can be performed using real arithmetics with only polynomial growth of computational resources in inverse temperature and time for integrable systems. The method is illustrated for the XXZ model and the single impurity Anderson model. (paper)

  7. Real time evolution at finite temperatures with operator space matrix product states

    Science.gov (United States)

    Pižorn, Iztok; Eisler, Viktor; Andergassen, Sabine; Troyer, Matthias

    2014-07-01

    We propose a method to simulate the real time evolution of one-dimensional quantum many-body systems at finite temperature by expressing both the density matrices and the observables as matrix product states. This allows the calculation of expectation values and correlation functions as scalar products in operator space. The simulations of density matrices in inverse temperature and the local operators in the Heisenberg picture are independent and result in a grid of expectation values for all intermediate temperatures and times. Simulations can be performed using real arithmetics with only polynomial growth of computational resources in inverse temperature and time for integrable systems. The method is illustrated for the XXZ model and the single impurity Anderson model.

  8. Universality in a Neutral Evolution Model

    Science.gov (United States)

    King, Dawn; Scott, Adam; Maric, Nevena; Bahar, Sonya

    2013-03-01

    Agent-based models are ideal for investigating the complex problems of biodiversity and speciation because they allow for complex interactions between individuals and between individuals and the environment. Presented here is a ``null'' model that investigates three mating types - assortative, bacterial, and random - in phenotype space, as a function of the percentage of random death δ. Previous work has shown phase transition behavior in an assortative mating model with variable fitness landscapes as the maximum mutation size (μ) was varied (Dees and Bahar, 2010). Similarly, this behavior was recently presented in the work of Scott et al. (submitted), on a completely neutral landscape, for bacterial-like fission as well as for assortative mating. Here, in order to achieve an appropriate ``null'' hypothesis, the random death process was changed so each individual, in each generation, has the same probability of death. Results show a continuous nonequilibrium phase transition for the order parameters of the population size and the number of clusters (analogue of species) as δ is varied for three different mutation sizes of the system. The system shows increasing robustness as μ increases. Universality classes and percolation properties of this system are also explored. This research was supported by funding from: University of Missouri Research Board and James S. McDonnell Foundation

  9. Overdeepening development in a glacial landscape evolution model with quarrying

    DEFF Research Database (Denmark)

    Ugelvig, Sofie Vej; Egholm, D.L.; Iverson, Neal R.

    In glacial landscape evolution models, subglacial erosion rates are often related to basal sliding or ice discharge by a power-law. This relation can be justified when considering bed abrasion, where rock debris transported in the basal ice drives erosion. However, the relation is not well...... supported when considering models for quarrying of rock blocks from the bed. Field observations indicate that the principal mechanism of glacial erosion is quarrying, which emphasize the importance of a better way of implementing erosion by quarrying in glacial landscape evolution models. Iverson (2012...... around the obstacles. The erosion rate is quantified by considering the likelihood of rock fracturing on topographic bumps. The model includes a statistical treatment of the bedrock weakness, which is neglected in previous quarrying models. Sliding rate, effective pressure, and average bedslope...

  10. Origin and evolution of the Community Health Agent Program in Ceará state -

    Directory of Open Access Journals (Sweden)

    Maria Marlene Marques Ávila

    2012-01-01

    Full Text Available Objective: To outline the origin and evolution of the work of Community Health Agents (ACS in Ceará. Data synthesis: A review of the literature pertaining to the subject and interviews with technicians from Ceará State Health Secretariat (SESA-Ce and from Ceará Public Health School (ESP-Ce were the sources of the data collected. Initially, we discussed the social and political scenario in which primary health care developed in the state, emphasizing the evolution of socioeconomic indicators and infant health. Then, we did a brief exposure of health care model and from then on, we focused on the Community Health Agent Program, since its origin as an emergency program, its integration into the Family Health Strategy, the repercussions of this insertion in the work of the Community Health Agent and the need for training of ACS. Conclusion: A discussion on the process of training of ACS was presented seeking dialogue with the necessary training in face of new health needs of the population, and most of all, strengthening the role of ACS as a mediator between families and health professionals at local level.

  11. HIV-specific probabilistic models of protein evolution.

    Directory of Open Access Journals (Sweden)

    David C Nickle

    2007-06-01

    Full Text Available Comparative sequence analyses, including such fundamental bioinformatics techniques as similarity searching, sequence alignment and phylogenetic inference, have become a mainstay for researchers studying type 1 Human Immunodeficiency Virus (HIV-1 genome structure and evolution. Implicit in comparative analyses is an underlying model of evolution, and the chosen model can significantly affect the results. In general, evolutionary models describe the probabilities of replacing one amino acid character with another over a period of time. Most widely used evolutionary models for protein sequences have been derived from curated alignments of hundreds of proteins, usually based on mammalian genomes. It is unclear to what extent these empirical models are generalizable to a very different organism, such as HIV-1-the most extensively sequenced organism in existence. We developed a maximum likelihood model fitting procedure to a collection of HIV-1 alignments sampled from different viral genes, and inferred two empirical substitution models, suitable for describing between-and within-host evolution. Our procedure pools the information from multiple sequence alignments, and provided software implementation can be run efficiently in parallel on a computer cluster. We describe how the inferred substitution models can be used to generate scoring matrices suitable for alignment and similarity searches. Our models had a consistently superior fit relative to the best existing models and to parameter-rich data-driven models when benchmarked on independent HIV-1 alignments, demonstrating evolutionary biases in amino-acid substitution that are unique to HIV, and that are not captured by the existing models. The scoring matrices derived from the models showed a marked difference from common amino-acid scoring matrices. The use of an appropriate evolutionary model recovered a known viral transmission history, whereas a poorly chosen model introduced phylogenetic

  12. Evolution of the Oxidation State of the Earth's Mantle

    Science.gov (United States)

    Danielson, L. R.; Righter, K.; Keller, L.; Christoffersen, E.; Rahman, Z.

    2015-01-01

    The oxidation state of the Earth's mantle during formation remains an unresolved question, whether it was constant throughout planetary accretion, transitioned from reduced to oxidized, or from oxidized to reduced. We investigate the stability of Fe3(+) at depth, in order to constrain processes (water, late accretion, dissociation of FeO) which may reduce or oxidize the Earth's mantle. In our previous experiments on shergottite compositions, variable fO2, T, and P less than 4 GPa, Fe3(+)/sigma Fe decreased slightly with increasing P, similar to terrestrial basalt. For oxidizing experiments less than 7GPa, Fe3(+)/sigma Fe decreased as well, but it's unclear from previous modelling whether the deeper mantle could retain significant Fe3(+). Our current experiments expand our pressure range deeper into the Earth's mantle and focus on compositions and conditions relevant to the early Earth. Preliminary multi-anvil experiments with Knippa basalt as the starting composition were conducted at 5-7 GPa and 1800 C, using a molybdenum capsule to set the fO2 near IW, by buffering with Mo-MoO3. TEM and EELS analyses revealed the run products quenched to polycrystalline phases, with the major phase pyroxene containing approximately equal to Fe3(+)/2(+). Experiments are underway to produce glassy samples that can be measured by EELS and XANES, and are conducted at higher pressures.

  13. The infinite sites model of genome evolution.

    Science.gov (United States)

    Ma, Jian; Ratan, Aakrosh; Raney, Brian J; Suh, Bernard B; Miller, Webb; Haussler, David

    2008-09-23

    We formalize the problem of recovering the evolutionary history of a set of genomes that are related to an unseen common ancestor genome by operations of speciation, deletion, insertion, duplication, and rearrangement of segments of bases. The problem is examined in the limit as the number of bases in each genome goes to infinity. In this limit, the chromosomes are represented by continuous circles or line segments. For such an infinite-sites model, we present a polynomial-time algorithm to find the most parsimonious evolutionary history of any set of related present-day genomes.

  14. The effects of self-interstitial clusters on cascade defect evolution beyond the primary damage state

    Energy Technology Data Exchange (ETDEWEB)

    Heinisch, H.L. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-04-01

    The intracascade evolution of the defect distributions of cascades in copper is investigated using stochastic annealing simulations applied to cascades generated with molecular dynamics (MD). The temperature and energy dependencies of annihilation, clustering and free defect production are determined for individual cascades. The annealing simulation results illustrate the strong influence on intracascade evolution of the defect configuration existing in the primary damage state. Another factor significantly affecting the evolution of the defect distribution is the rapid one-dimensional diffusion of small, glissile interstitial loops produced directly in cascades. This phenomenon introduces a cascade energy dependence of defect evolution that is apparent only beyond the primary damage state, amplifying the need for further study of the annealing phase of cascade evolution and for performing many more MD cascade simulations at higher energies.

  15. The effects of self-interstitial clusters on cascade defect evolution beyond the primary damage state

    International Nuclear Information System (INIS)

    Heinisch, H.L.

    1997-01-01

    The intracascade evolution of the defect distributions of cascades in copper is investigated using stochastic annealing simulations applied to cascades generated with molecular dynamics (MD). The temperature and energy dependencies of annihilation, clustering and free defect production are determined for individual cascades. The annealing simulation results illustrate the strong influence on intracascade evolution of the defect configuration existing in the primary damage state. Another factor significantly affecting the evolution of the defect distribution is the rapid one-dimensional diffusion of small, glissile interstitial loops produced directly in cascades. This phenomenon introduces a cascade energy dependence of defect evolution that is apparent only beyond the primary damage state, amplifying the need for further study of the annealing phase of cascade evolution and for performing many more MD cascade simulations at higher energies

  16. Modeling river dune evolution using a parameterization of flow separation

    NARCIS (Netherlands)

    Paarlberg, Andries J.; Dohmen-Janssen, C. Marjolein; Hulscher, Suzanne J.M.H.; Termes, Paul

    2009-01-01

    This paper presents an idealized morphodynamic model to predict river dune evolution. The flow field is solved in a vertical plane assuming hydrostatic pressure conditions. The sediment transport is computed using a Meyer-Peter–Müller type of equation, including gravitational bed slope effects and a

  17. Coastal Foredune Evolution, Part 2: Modeling Approaches for Meso-Scale Morphologic Evolution

    Science.gov (United States)

    2017-03-01

    for Meso-Scale Morphologic Evolution by Margaret L. Palmsten1, Katherine L. Brodie2, and Nicholas J. Spore2 PURPOSE: This Coastal and Hydraulics ...managers because foredunes provide ecosystem services and can reduce storm damages to coastal infrastructure, both of which increase the resiliency...MS 2 U.S. Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, Duck, NC ERDC/CHL CHETN-II-57 March 2017 2 models of

  18. Digital Forensic Investigation Models, an Evolution study

    Directory of Open Access Journals (Sweden)

    Khuram Mushtaque

    2015-10-01

    Full Text Available In business today, one of the most important segments that enable any business to get competitive advantage over others is appropriate, effective adaptation of Information Technology into business and then managing and governing it on their will. To govern IT organizations need to identify value of acquiring services of forensic firms to compete cyber criminals. Digital forensic firms follow different mechanisms to perform investigation. Time by time forensic firms are facilitated with different models for investigation containing phases for different purposes of the entire process. Along with forensic firms, enterprises also need to build a secure and supportive platform to make successful investigation process possible. We have underlined different elements of organizations in Pakistan; need to be addressed to provide support to forensic firms.

  19. Observational constraints from models of close binary evolution

    International Nuclear Information System (INIS)

    Greve, J.P. de; Packet, W.

    1984-01-01

    The evolution of a system of 9 solar masses + 5.4 solar masses is computed from Zero Age Main Sequence through an early case B of mass exchange, up to the second phase of mass transfer after core helium burning. Both components are calculated simultaneously. The evolution is divided into several physically different phases. The characteristics of the models in each of these phases are transformed into corresponding 'observable' quantities. The outlook of the system for photometric observations is discussed, for an idealized case. The influence of the mass of the loser and the initial mass ratio is considered. (Auth.)

  20. Anomalous diffusion in neutral evolution of model proteins

    Science.gov (United States)

    Nelson, Erik D.; Grishin, Nick V.

    2015-06-01

    Protein evolution is frequently explored using minimalist polymer models, however, little attention has been given to the problem of structural drift, or diffusion. Here, we study neutral evolution of small protein motifs using an off-lattice heteropolymer model in which individual monomers interact as low-resolution amino acids. In contrast to most earlier models, both the length and folded structure of the polymers are permitted to change. To describe structural change, we compute the mean-square distance (MSD) between monomers in homologous folds separated by n neutral mutations. We find that structural change is episodic, and, averaged over lineages (for example, those extending from a single sequence), exhibits a power-law dependence on n . We show that this exponent depends on the alignment method used, and we analyze the distribution of waiting times between neutral mutations. The latter are more disperse than for models required to maintain a specific fold, but exhibit a similar power-law tail.

  1. An Empirical LTE Smartphone Power Model with a View to Energy Efficiency Evolution

    DEFF Research Database (Denmark)

    Lauridsen, Mads; Noël, Laurent; Sørensen, Troels Bundgaard

    2014-01-01

    measurements made on state-of-the-art LTE smartphones. Discontinuous Reception (DRX) sleep mode is also modeled, because it is one of the most effective methods to improve smartphone battery life. Energy efficiency has generally improved with each Radio Access Technology (RAT) generation, and to see......Smartphone users struggle with short battery life, and this affects their device satisfaction level and usage of the network. To evaluate how chipset manufacturers and mobile network operators can improve the battery life, we propose a Long Term Evolution (LTE) smartphone power model. The idea...... this evolution, we compare the energy efficiency of the latest LTE devices with devices based on Enhanced Data rates for GSM Evolution (EDGE), High Speed Packet Access (HSPA), and Wi-Fi*. With further generations of RAT systems we expect further improvements. To this end, we discuss the new LTE features, Carrier...

  2. MODELING THE RED SEQUENCE: HIERARCHICAL GROWTH YET SLOW LUMINOSITY EVOLUTION

    International Nuclear Information System (INIS)

    Skelton, Rosalind E.; Bell, Eric F.; Somerville, Rachel S.

    2012-01-01

    We explore the effects of mergers on the evolution of massive early-type galaxies by modeling the evolution of their stellar populations in a hierarchical context. We investigate how a realistic red sequence population set up by z ∼ 1 evolves under different assumptions for the merger and star formation histories, comparing changes in color, luminosity, and mass. The purely passive fading of existing red sequence galaxies, with no further mergers or star formation, results in dramatic changes at the bright end of the luminosity function and color-magnitude relation. Without mergers there is too much evolution in luminosity at a fixed space density compared to observations. The change in color and magnitude at a fixed mass resembles that of a passively evolving population that formed relatively recently, at z ∼ 2. Mergers among the red sequence population ('dry mergers') occurring after z = 1 build up mass, counteracting the fading of the existing stellar populations to give smaller changes in both color and luminosity for massive galaxies. By allowing some galaxies to migrate from the blue cloud onto the red sequence after z = 1 through gas-rich mergers, younger stellar populations are added to the red sequence. This manifestation of the progenitor bias increases the scatter in age and results in even smaller changes in color and luminosity between z = 1 and z = 0 at a fixed mass. The resultant evolution appears much slower, resembling the passive evolution of a population that formed at high redshift (z ∼ 3-5), and is in closer agreement with observations. We conclude that measurements of the luminosity and color evolution alone are not sufficient to distinguish between the purely passive evolution of an old population and cosmologically motivated hierarchical growth, although these scenarios have very different implications for the mass growth of early-type galaxies over the last half of cosmic history.

  3. Reservoir pressure evolution model during exploration drilling

    Directory of Open Access Journals (Sweden)

    Korotaev B. A.

    2017-03-01

    Full Text Available Based on the analysis of laboratory studies and literature data the method for estimating reservoir pressure in exploratory drilling has been proposed, it allows identify zones of abnormal reservoir pressure in the presence of seismic data on reservoir location depths. This method of assessment is based on developed at the end of the XX century methods using d- and σ-exponentials taking into account the mechanical drilling speed, rotor speed, bit load and its diameter, lithological constant and degree of rocks' compaction, mud density and "regional density". It is known that in exploratory drilling pulsation of pressure at the wellhead is observed. Such pulsation is a consequence of transferring reservoir pressure through clay. In the paper the mechanism for transferring pressure to the bottomhole as well as the behaviour of the clay layer during transmission of excess pressure has been described. A laboratory installation has been built, it has been used for modelling pressure propagation to the bottomhole of the well through a layer of clay. The bulge of the clay layer is established for 215.9 mm bottomhole diameter. Functional correlation of pressure propagation through the layer of clay has been determined and a reaction of the top clay layer has been shown to have bulge with a height of 25 mm. A pressure distribution scheme (balance has been developed, which takes into account the distance from layers with abnormal pressure to the bottomhole. A balance equation for reservoir pressure evaluation has been derived including well depth, distance from bottomhole to the top of the formation with abnormal pressure and density of clay.

  4. Modeling evolution and immune system by cellular automata

    International Nuclear Information System (INIS)

    Bezzi, M.

    2001-01-01

    In this review the behavior of two different biological systems is investigated using cellular automata. Starting from this spatially extended approach it is also tried, in some cases, to reduce the complexity of the system introducing mean-field approximation, and solving (or trying to solve) these simplified systems. It is discussed the biological meaning of the results, the comparison with experimental data (if available) and the different features between spatially extended and mean-field versions. The biological systems considered in this review are the following: Darwinian evolution in simple ecosystems and immune system response. In the first section the main features of molecular evolution are introduced, giving a short survey of genetics for physicists and discussing some models for prebiotic systems and simple ecosystems. It is also introduced a cellular automaton model for studying a set of evolving individuals in a general fitness landscape, considering also the effects of co-evolution. In particular the process of species formation (speciation) is described in sect. 5. The second part deals with immune system modeling. The biological features of immune response are discussed, as well as it is introduced the concept of shape space and of idiotypic network. More detailed reviews which deal with immune system models (mainly focused on idiotypic network models) can be found. Other themes here discussed: the applications of CA to immune system modeling, two complex cellular automata for humoral and cellular immune response. Finally, it is discussed the biological data and the general conclusions are drawn in the last section

  5. PROTOPLANETARY DISK STRUCTURE WITH GRAIN EVOLUTION: THE ANDES MODEL

    International Nuclear Information System (INIS)

    Akimkin, V.; Wiebe, D.; Pavlyuchenkov, Ya.; Zhukovska, S.; Semenov, D.; Henning, Th.; Vasyunin, A.; Birnstiel, T.

    2013-01-01

    We present a self-consistent model of a protoplanetary disk: 'ANDES' ('AccretioN disk with Dust Evolution and Sedimentation'). ANDES is based on a flexible and extendable modular structure that includes (1) a 1+1D frequency-dependent continuum radiative transfer module, (2) a module to calculate the chemical evolution using an extended gas-grain network with UV/X-ray-driven processes and surface reactions, (3) a module to calculate the gas thermal energy balance, and (4) a 1+1D module that simulates dust grain evolution. For the first time, grain evolution and time-dependent molecular chemistry are included in a protoplanetary disk model. We find that grain growth and sedimentation of large grains onto the disk midplane lead to a dust-depleted atmosphere. Consequently, dust and gas temperatures become higher in the inner disk (R ∼ 50 AU), in comparison with the disk model with pristine dust. The response of disk chemical structure to the dust growth and sedimentation is twofold. First, due to higher transparency a partly UV-shielded molecular layer is shifted closer to the dense midplane. Second, the presence of big grains in the disk midplane delays the freeze-out of volatile gas-phase species such as CO there, while in adjacent upper layers the depletion is still effective. Molecular concentrations and thus column densities of many species are enhanced in the disk model with dust evolution, e.g., CO 2 , NH 2 CN, HNO, H 2 O, HCOOH, HCN, and CO. We also show that time-dependent chemistry is important for a proper description of gas thermal balance.

  6. The role of globalization in the evolution of welfare state functions

    Directory of Open Access Journals (Sweden)

    V. P. Vasiliev

    2015-01-01

    Full Text Available This article describes a set of problems of evolution of the modern state. Tendencies modification of the territorial state in the context of globalization. Explore the possibility of going to the institutions of the new world order, marked their shortcomings, not to effectively solve the accumulated social problems. It is shown that the crisis of the modern welfare state is not predetermined by the state as a social institution of society; the causes are genetic properties of a market economy.

  7. Topographic evolution of sandbars: Flume experiment and computational modeling

    Science.gov (United States)

    Kinzel, Paul J.; Nelson, Jonathan M.; McDonald, Richard R.; Logan, Brandy L.

    2010-01-01

    Measurements of sandbar formation and evolution were carried out in a laboratory flume and the topographic characteristics of these barforms were compared to predictions from a computational flow and sediment transport model with bed evolution. The flume experiment produced sandbars with approximate mode 2, whereas numerical simulations produced a bed morphology better approximated as alternate bars, mode 1. In addition, bar formation occurred more rapidly in the laboratory channel than for the model channel. This paper focuses on a steady-flow laboratory experiment without upstream sediment supply. Future experiments will examine the effects of unsteady flow and sediment supply and the use of numerical models to simulate the response of barform topography to these influences.

  8. The Supercritical Pile GRB Model: The Prompt to Afterglow Evolution

    Science.gov (United States)

    Mastichiadis, A.; Kazanas, D.

    2009-01-01

    The "Supercritical Pile" is a very economical GRB model that provides for the efficient conversion of the energy stored in the protons of a Relativistic Blast Wave (RBW) into radiation and at the same time produces - in the prompt GRB phase, even in the absence of any particle acceleration - a spectral peak at energy approx. 1 MeV. We extend this model to include the evolution of the RBW Lorentz factor Gamma and thus follow its spectral and temporal features into the early GRB afterglow stage. One of the novel features of the present treatment is the inclusion of the feedback of the GRB produced radiation on the evolution of Gamma with radius. This feedback and the presence of kinematic and dynamic thresholds in the model can be the sources of rich time evolution which we have began to explore. In particular. one can this may obtain afterglow light curves with steep decays followed by the more conventional flatter afterglow slopes, while at the same time preserving the desirable features of the model, i.e. the well defined relativistic electron source and radiative processes that produce the proper peak in the (nu)F(sub nu), spectra. In this note we present the results of a specific set of parameters of this model with emphasis on the multiwavelength prompt emission and transition to the early afterglow.

  9. Adaptive Multiscale Modeling of Geochemical Impacts on Fracture Evolution

    Science.gov (United States)

    Molins, S.; Trebotich, D.; Steefel, C. I.; Deng, H.

    2016-12-01

    Understanding fracture evolution is essential for many subsurface energy applications, including subsurface storage, shale gas production, fracking, CO2 sequestration, and geothermal energy extraction. Geochemical processes in particular play a significant role in the evolution of fractures through dissolution-driven widening, fines migration, and/or fracture sealing due to precipitation. One obstacle to understanding and exploiting geochemical fracture evolution is that it is a multiscale process. However, current geochemical modeling of fractures cannot capture this multi-scale nature of geochemical and mechanical impacts on fracture evolution, and is limited to either a continuum or pore-scale representation. Conventional continuum-scale models treat fractures as preferential flow paths, with their permeability evolving as a function (often, a cubic law) of the fracture aperture. This approach has the limitation that it oversimplifies flow within the fracture in its omission of pore scale effects while also assuming well-mixed conditions. More recently, pore-scale models along with advanced characterization techniques have allowed for accurate simulations of flow and reactive transport within the pore space (Molins et al., 2014, 2015). However, these models, even with high performance computing, are currently limited in their ability to treat tractable domain sizes (Steefel et al., 2013). Thus, there is a critical need to develop an adaptive modeling capability that can account for separate properties and processes, emergent and otherwise, in the fracture and the rock matrix at different spatial scales. Here we present an adaptive modeling capability that treats geochemical impacts on fracture evolution within a single multiscale framework. Model development makes use of the high performance simulation capability, Chombo-Crunch, leveraged by high resolution characterization and experiments. The modeling framework is based on the adaptive capability in Chombo

  10. Functional State Modelling of Cultivation Processes: Dissolved Oxygen Limitation State

    Directory of Open Access Journals (Sweden)

    Olympia Roeva

    2015-04-01

    Full Text Available A new functional state, namely dissolved oxygen limitation state for both bacteria Escherichia coli and yeast Saccharomyces cerevisiae fed-batch cultivation processes is presented in this study. Functional state modelling approach is applied to cultivation processes in order to overcome the main disadvantages of using global process model, namely complex model structure and a big number of model parameters. Alongwith the newly introduced dissolved oxygen limitation state, second acetate production state and first acetate production state are recognized during the fed-batch cultivation of E. coli, while mixed oxidative state and first ethanol production state are recognized during the fed-batch cultivation of S. cerevisiae. For all mentioned above functional states both structural and parameter identification is here performed based on experimental data of E. coli and S. cerevisiae fed-batch cultivations.

  11. Entanglement Evolution of Jaynes-Cummings Model in Resonance Case and Non-resonance Case

    Science.gov (United States)

    Cheng, Jing; Chen, Xi; Shan, Chuan-Jia

    2018-03-01

    We investigate the entanglement evolution of a two-level atom and a quantized single model electromagnetic filed in the resonance and non-resonance cases. The effects of the initial state, detuning degree, photon number on the entanglement are shown in detail. The results show that the atom-cavity entanglement state appears with periodicity. The increasing of the photon number can make the period of quantum entanglement be shorter. In the non-resonant case, if we choose the suitable initial state the entanglement of atom-cavity can be 1.0

  12. Deciphering excited state evolution in halorhodopsin with stimulated emission pumping.

    Science.gov (United States)

    Bismuth, Oshrat; Komm, Pavel; Friedman, Noga; Eliash, Tamar; Sheves, Mordechai; Ruhman, Sanford

    2010-03-04

    The primary photochemical dynamics of Hb. pharaonis Halorhodopsin (pHR) are investigated by femtosecond visible pump-near IR dump-hyperspectral probe spectroscopy. The efficiency of excited state depletion is deduced from transient changes in absorption, recorded with and without stimulated emission pumping (SEP), as a function of the dump delay. The concomitant reduction of photocycle population is assessed by probing the "K" intermediate difference spectrum. Results show that the cross section for stimulating emission is nearly constant throughout the fluorescent state lifetime. Probing "K" demonstrates that dumping produces a proportionate reduction in photocycle yields. We conclude that, despite its nonexponential internal conversion (IC) kinetics, the fluorescent state in pHR constitutes a single intermediate in the photocycle. This contrasts with conclusions drawn from the study of primary events in the related chloride pump from Hb. salinarum (sHR), believed to produce the "K" intermediate from a distinct short-lived subpopulation in the excited state. Our discoveries concerning internal conversion dynamics in pHR are discussed in light of recent expectations for similar excited state dynamics in both proteins.

  13. A model of epigenetic evolution based on theory of open quantum systems.

    Science.gov (United States)

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

    2013-12-01

    We present a very general model of epigenetic evolution unifying (neo-)Darwinian and (neo-)Lamarckian viewpoints. The evolution is represented in the form of adaptive dynamics given by the quantum(-like) master equation. This equation describes development of the information state of epigenome under the pressure of an environment. We use the formalism of quantum mechanics in the purely operational framework. (Hence, our model has no direct relation to quantum physical processes inside a cell.) Thus our model is about probabilities for observations which can be done on epigenomes and it does not provide a detailed description of cellular processes. Usage of the operational approach provides a possibility to describe by one model all known types of cellular epigenetic inheritance.

  14. Exploring the drivers and elements of subsidiary evolution in several new EU member states

    NARCIS (Netherlands)

    Filippov, S.; Duijsters, G.M.

    2014-01-01

    Purpose – Management of subsidiaries of multinational companies and subsidiary evolution have emerged as important topics in the international business literature. This strand of literature on multinational subsidiaries has provided the necessary analytical models and research tools to study the

  15. Modeling Evolution on Nearly Neutral Network Fitness Landscapes

    Science.gov (United States)

    Yakushkina, Tatiana; Saakian, David B.

    2017-08-01

    To describe virus evolution, it is necessary to define a fitness landscape. In this article, we consider the microscopic models with the advanced version of neutral network fitness landscapes. In this problem setting, we suppose a fitness difference between one-point mutation neighbors to be small. We construct a modification of the Wright-Fisher model, which is related to ordinary infinite population models with nearly neutral network fitness landscape at the large population limit. From the microscopic models in the realistic sequence space, we derive two versions of nearly neutral network models: with sinks and without sinks. We claim that the suggested model describes the evolutionary dynamics of RNA viruses better than the traditional Wright-Fisher model with few sequences.

  16. Entropy in the Tangled Nature Model of evolution

    DEFF Research Database (Denmark)

    Roach, Ty N.F.; Nulton, James; Sibani, Paolo

    2017-01-01

    Applications of entropy principles to evolution and ecology are of tantamount importance given the central role spatiotemporal structuring plays in both evolution and ecological succession. We obtain here a qualitative interpretation of the role of entropy in evolving ecological systems. Our...... interpretation is supported by mathematical arguments using simulation data generated by the Tangled Nature Model (TNM), a stochastic model of evolving ecologies. We define two types of configurational entropy and study their empirical time dependence obtained from the data. Both entropy measures increase...... logarithmically with time, while the entropy per individual decreases in time, in parallel with the growth of emergent structures visible from other aspects of the simulation. We discuss the biological relevance of these entropies to describe niche space and functional space of ecosystems, as well as their use...

  17. Evolution of United States Military Landmine Doctrine and Employment

    Science.gov (United States)

    2015-06-12

    swaths of the enemy at once. MacLeod, whose name was obviously of Scottish derivation, called his mine the Claymore. After a few revisions it was...merits intense study, as the United States cannot expect to continue to fight enemies massed in rural areas. Nuclear warfare should still be studied as

  18. Nonlinear evolution inclusions arising from phase change models

    Czech Academy of Sciences Publication Activity Database

    Colli, P.; Krejčí, Pavel; Rocca, E.; Sprekels, J.

    2007-01-01

    Roč. 57, č. 4 (2007), s. 1067-1098 ISSN 0011-4642 R&D Projects: GA ČR GA201/02/1058 Institutional research plan: CEZ:AV0Z10190503 Keywords : nonlinear and nonlocal evolution equations * Cahn-Hilliard type dynamics * phase transitions models Subject RIV: BA - General Mathematics Impact factor: 0.155, year: 2007 http://www.dml.cz/bitstream/handle/10338.dmlcz/128228/CzechMathJ_57-2007-4_2.pdf

  19. Geochemical modelling of groundwater evolution using chemical equilibrium codes

    International Nuclear Information System (INIS)

    Pitkaenen, P.; Pirhonen, V.

    1991-01-01

    Geochemical equilibrium codes are a modern tool in studying interaction between groundwater and solid phases. The most common used programs and application subjects are shortly presented in this article. The main emphasis is laid on the approach method of using calculated results in evaluating groundwater evolution in hydrogeological system. At present in geochemical equilibrium modelling also kinetic as well as hydrologic constrains along a flow path are taken into consideration

  20. Moving in the Right Direction: Evolution of Protein Structural Vibrations with Functional State and Mutation

    Science.gov (United States)

    Niessen, Katherine; Xu, Mengyang; Snell, Edward; Markelz, Andrea

    Long-range intramolecular vibrations may enable efficient access to functionally important conformations. We examine how these motions change with inhibitor binding and mutation using terahertz anisotropic absorption and molecular modeling. The measured anisotropic absorption dramatically changes with 3NAG inhibitor binding for wild type (WT) free chicken egg white lysozyme (CEWL). We examine the evolution of internal motions with binding using normal mode analysis to calculate an ensemble averaged vibrational density of states (VDOS) and isotropic and anisotropic absorptions for both WT and a two residue (R14 and H15) deletion mutant which has a 1.4 higher activity rate. While the VDOS and isotropic response are largely unchanged with inhibitor binding, the anisotropic response changes dramatically with binding. However, for the mutant the calculated unbound anisotropic absorption more closely resembles its bound spectrum, and it has increased calculated mean squared fluctuations in regions overlapping those in its bound state. These results indicate that the mutant's enhanced activity may be due to a shift in the direction of vibrations toward those of the bound state, increasing the sampling rate of the bound conformation.

  1. Active State Model for Autonomous Systems

    Science.gov (United States)

    Park, Han; Chien, Steve; Zak, Michail; James, Mark; Mackey, Ryan; Fisher, Forest

    2003-01-01

    The concept of the active state model (ASM) is an architecture for the development of advanced integrated fault-detection-and-isolation (FDI) systems for robotic land vehicles, pilotless aircraft, exploratory spacecraft, or other complex engineering systems that will be capable of autonomous operation. An FDI system based on the ASM concept would not only provide traditional diagnostic capabilities, but also integrate the FDI system under a unified framework and provide mechanism for sharing of information between FDI subsystems to fully assess the overall health of the system. The ASM concept begins with definitions borrowed from psychology, wherein a system is regarded as active when it possesses self-image, self-awareness, and an ability to make decisions itself, such that it is able to perform purposeful motions and other transitions with some degree of autonomy from the environment. For an engineering system, self-image would manifest itself as the ability to determine nominal values of sensor data by use of a mathematical model of itself, and selfawareness would manifest itself as the ability to relate sensor data to their nominal values. The ASM for such a system may start with the closed-loop control dynamics that describe the evolution of state variables. As soon as this model was supplemented with nominal values of sensor data, it would possess self-image. The ability to process the current sensor data and compare them with the nominal values would represent self-awareness. On the basis of self-image and self-awareness, the ASM provides the capability for self-identification, detection of abnormalities, and self-diagnosis.

  2. Bayesian nonparametric clustering in phylogenetics: modeling antigenic evolution in influenza.

    Science.gov (United States)

    Cybis, Gabriela B; Sinsheimer, Janet S; Bedford, Trevor; Rambaut, Andrew; Lemey, Philippe; Suchard, Marc A

    2018-01-30

    Influenza is responsible for up to 500,000 deaths every year, and antigenic variability represents much of its epidemiological burden. To visualize antigenic differences across many viral strains, antigenic cartography methods use multidimensional scaling on binding assay data to map influenza antigenicity onto a low-dimensional space. Analysis of such assay data ideally leads to natural clustering of influenza strains of similar antigenicity that correlate with sequence evolution. To understand the dynamics of these antigenic groups, we present a framework that jointly models genetic and antigenic evolution by combining multidimensional scaling of binding assay data, Bayesian phylogenetic machinery and nonparametric clustering methods. We propose a phylogenetic Chinese restaurant process that extends the current process to incorporate the phylogenetic dependency structure between strains in the modeling of antigenic clusters. With this method, we are able to use the genetic information to better understand the evolution of antigenicity throughout epidemics, as shown in applications of this model to H1N1 influenza. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  3. The Institutional Approach for Modeling the Evolution of Human Societies.

    Science.gov (United States)

    Powers, Simon T

    2018-01-01

    Artificial life is concerned with understanding the dynamics of human societies. A defining feature of any society is its institutions. However, defining exactly what an institution is has proven difficult, with authors often talking past each other. This article presents a dynamic model of institutions, which views them as political game forms that generate the rules of a group's economic interactions. Unlike most prior work, the framework presented here allows for the construction of explicit models of the evolution of institutional rules. It takes account of the fact that group members are likely to try to create rules that benefit themselves. Following from this, it allows us to determine the conditions under which self-interested individuals will create institutional rules that support cooperation-for example, that prevent a tragedy of the commons. The article finishes with an example of how a model of the evolution of institutional rewards and punishments for promoting cooperation can be created. It is intended that this framework will allow artificial life researchers to examine how human groups can themselves create conditions for cooperation. This will help provide a better understanding of historical human social evolution, and facilitate the resolution of pressing societal social dilemmas.

  4. State-space prediction model for chaotic time series

    Science.gov (United States)

    Alparslan, A. K.; Sayar, M.; Atilgan, A. R.

    1998-08-01

    A simple method for predicting the continuation of scalar chaotic time series ahead in time is proposed. The false nearest neighbors technique in connection with the time-delayed embedding is employed so as to reconstruct the state space. A local forecasting model based upon the time evolution of the topological neighboring in the reconstructed phase space is suggested. A moving root-mean-square error is utilized in order to monitor the error along the prediction horizon. The model is tested for the convection amplitude of the Lorenz model. The results indicate that for approximately 100 cycles of the training data, the prediction follows the actual continuation very closely about six cycles. The proposed model, like other state-space forecasting models, captures the long-term behavior of the system due to the use of spatial neighbors in the state space.

  5. Learning by doing: The evolution of state support for photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Bolinger, Mark; Wiser, Ryan

    2003-06-01

    Fifteen states have established ''clean energy funds'' that will collect more than $3 billion in aggregate from ratepayers over the next decade. The general mission of these funds is to support the development of renewable energy technologies and markets; all of the funds target the installation of photovoltaics (PV) in one way or another. So-called ''buy-down'' programs--i.e., programs that offset the high up-front costs of PV through capital grants or rebates--have been the most popular approach taken to date in supporting PV. At present, however, state clean energy funds appear to be evolving into a new phase of supporting PV--one that draws upon lessons learned from the past few years' experience with the first round of buy-down programs. This paper briefly discusses these lessons from the past and describes how various states are tweaking, rearranging, or crafting new programs to incorporate those lessons.

  6. SIGNUM: A Matlab, TIN-based landscape evolution model

    Science.gov (United States)

    Refice, A.; Giachetta, E.; Capolongo, D.

    2012-08-01

    Several numerical landscape evolution models (LEMs) have been developed to date, and many are available as open source codes. Most are written in efficient programming languages such as Fortran or C, but often require additional code efforts to plug in to more user-friendly data analysis and/or visualization tools to ease interpretation and scientific insight. In this paper, we present an effort to port a common core of accepted physical principles governing landscape evolution directly into a high-level language and data analysis environment such as Matlab. SIGNUM (acronym for Simple Integrated Geomorphological Numerical Model) is an independent and self-contained Matlab, TIN-based landscape evolution model, built to simulate topography development at various space and time scales. SIGNUM is presently capable of simulating hillslope processes such as linear and nonlinear diffusion, fluvial incision into bedrock, spatially varying surface uplift which can be used to simulate changes in base level, thrust and faulting, as well as effects of climate changes. Although based on accepted and well-known processes and algorithms in its present version, it is built with a modular structure, which allows to easily modify and upgrade the simulated physical processes to suite virtually any user needs. The code is conceived as an open-source project, and is thus an ideal tool for both research and didactic purposes, thanks to the high-level nature of the Matlab environment and its popularity among the scientific community. In this paper the simulation code is presented together with some simple examples of surface evolution, and guidelines for development of new modules and algorithms are proposed.

  7. Evolution of the Collectivity around 68Ni: role of intruder states

    International Nuclear Information System (INIS)

    Dijon, A.

    2012-01-01

    The evolution of magic numbers as a function of the neutron number for a given chain of isotopes is one of the major goals of nuclear physics today. Changing magic numbers may lead to profound modifications in the structure of exotic nuclei and manifest themselves experimentally in rapid changes of collectivity and shapes. In this thesis we have studied nuclei around 68 Ni produced in deep inelastic collisions at GANIL. The nuclei of interest were selected and identified by the large acceptance VAMOS recoil spectrometer. Their structure was studied via the detection of the gamma rays emitted at the target point by the EXOGAM array. In one of the two experiments we also installed a specific setup dedicated to the measurements of the delayed gamma rays emitted by the nuclei after their implantation at the focal plane of VAMOS. In the first experiment we have observed a new isomeric state in 68 Ni with a proton intruder configuration at an excitation energy which sensitively depends on the Z=28 and N=40 shell gaps. New transitions were also identified in odd-mass isotopes of Co, Fe and Mn. In the second experiment we have measured the lifetimes of the first-excited states in 63,65 Co using the recoil distance Doppler shift method. From these lifetimes electromagnetic transition probabilities could be deduced, which in turn shed light on the collectivity of the studied isotopes. Comparisons with the shell model and with mean field calculations were carried and provided additional information on the proton-neutron interaction as well as on the evolution of the collectivity in this mass region. (author) [fr

  8. Modelling Influence and Opinion Evolution in Online Collective Behaviour.

    Directory of Open Access Journals (Sweden)

    Corentin Vande Kerckhove

    Full Text Available Opinion evolution and judgment revision are mediated through social influence. Based on a large crowdsourced in vitro experiment (n = 861, it is shown how a consensus model can be used to predict opinion evolution in online collective behaviour. It is the first time the predictive power of a quantitative model of opinion dynamics is tested against a real dataset. Unlike previous research on the topic, the model was validated on data which did not serve to calibrate it. This avoids to favor more complex models over more simple ones and prevents overfitting. The model is parametrized by the influenceability of each individual, a factor representing to what extent individuals incorporate external judgments. The prediction accuracy depends on prior knowledge on the participants' past behaviour. Several situations reflecting data availability are compared. When the data is scarce, the data from previous participants is used to predict how a new participant will behave. Judgment revision includes unpredictable variations which limit the potential for prediction. A first measure of unpredictability is proposed. The measure is based on a specific control experiment. More than two thirds of the prediction errors are found to occur due to unpredictability of the human judgment revision process rather than to model imperfection.

  9. Constraints and entropy in a model of network evolution

    Science.gov (United States)

    Tee, Philip; Wakeman, Ian; Parisis, George; Dawes, Jonathan; Kiss, István Z.

    2017-11-01

    Barabási-Albert's "Scale Free" model is the starting point for much of the accepted theory of the evolution of real world communication networks. Careful comparison of the theory with a wide range of real world networks, however, indicates that the model is in some cases, only a rough approximation to the dynamical evolution of real networks. In particular, the exponent γ of the power law distribution of degree is predicted by the model to be exactly 3, whereas in a number of real world networks it has values between 1.2 and 2.9. In addition, the degree distributions of real networks exhibit cut offs at high node degree, which indicates the existence of maximal node degrees for these networks. In this paper we propose a simple extension to the "Scale Free" model, which offers better agreement with the experimental data. This improvement is satisfying, but the model still does not explain why the attachment probabilities should favor high degree nodes, or indeed how constraints arrive in non-physical networks. Using recent advances in the analysis of the entropy of graphs at the node level we propose a first principles derivation for the "Scale Free" and "constraints" model from thermodynamic principles, and demonstrate that both preferential attachment and constraints could arise as a natural consequence of the second law of thermodynamics.

  10. Calibration of a stochastic health evolution model using NHIS data

    Science.gov (United States)

    Gupta, Aparna; Li, Zhisheng

    2011-10-01

    This paper presents and calibrates an individual's stochastic health evolution model. In this health evolution model, the uncertainty of health incidents is described by a stochastic process with a finite number of possible outcomes. We construct a comprehensive health status index (HSI) to describe an individual's health status, as well as a health risk factor system (RFS) to classify individuals into different risk groups. Based on the maximum likelihood estimation (MLE) method and the method of nonlinear least squares fitting, model calibration is formulated in terms of two mixed-integer nonlinear optimization problems. Using the National Health Interview Survey (NHIS) data, the model is calibrated for specific risk groups. Longitudinal data from the Health and Retirement Study (HRS) is used to validate the calibrated model, which displays good validation properties. The end goal of this paper is to provide a model and methodology, whose output can serve as a crucial component of decision support for strategic planning of health related financing and risk management.

  11. Modelling Long-Term Evolution of Cementitious Materials Used in Waste Disposal

    International Nuclear Information System (INIS)

    Jacques, D.; Perko, J.; Seetharam, S.; Govaerts, J.; Mallants, D.

    2013-01-01

    This report summarizes the latest developments at SCK-CEN in modelling long-term evolution of cementitious materials used as engineered barriers in waste disposal. In a first section chemical degradation of concrete during leaching with rain and soil water types is discussed. The geochemical evolution of concrete thus obtained forms the basis for all further modelling. Next we show how the leaching model is coupled with a reactive transport module to determine leaching of cement minerals under diffusive or advective boundary conditions. The module also contains a simplified microstructural model from which hydraulic and transport properties of concrete may be calculated dynamically. This coupled model is simplified, i.e. abstracted prior to being applied to large-scale concrete structures typical of a near-surface repository. Both the original and simplified models are then used to calculate the evolution of hydraulic, transport, and chemical properties of concrete. Characteristic degradation states of concrete are further linked to distribution ratios that describe sorption onto hardened cement via a linear and reversible sorption process. As concrete degrades and pH drops the distribution ratios are continuously updated. We have thus integrated all major chemical and physical concrete degradation processes into one simulator for a particular scale of interest. Two simulators are used: one that can operate at relatively small spatial scales using all process details and another one which simulates concrete degradation at the scale of the repository but with a simplified cement model representation. (author)

  12. Ontology and modeling patterns for state-based behavior representation

    Science.gov (United States)

    Castet, Jean-Francois; Rozek, Matthew L.; Ingham, Michel D.; Rouquette, Nicolas F.; Chung, Seung H.; Kerzhner, Aleksandr A.; Donahue, Kenneth M.; Jenkins, J. Steven; Wagner, David A.; Dvorak, Daniel L.; hide

    2015-01-01

    This paper provides an approach to capture state-based behavior of elements, that is, the specification of their state evolution in time, and the interactions amongst them. Elements can be components (e.g., sensors, actuators) or environments, and are characterized by state variables that vary with time. The behaviors of these elements, as well as interactions among them are represented through constraints on state variables. This paper discusses the concepts and relationships introduced in this behavior ontology, and the modeling patterns associated with it. Two example cases are provided to illustrate their usage, as well as to demonstrate the flexibility and scalability of the behavior ontology: a simple flashlight electrical model and a more complex spacecraft model involving instruments, power and data behaviors. Finally, an implementation in a SysML profile is provided.

  13. Geometrothermodynamic model for the evolution of the Universe

    Energy Technology Data Exchange (ETDEWEB)

    Gruber, Christine; Quevedo, Hernando, E-mail: christine.gruber@correo.nucleares.unam.mx, E-mail: quevedo@nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, AP 70543, México, DF 04510 (Mexico)

    2017-07-01

    Using the formalism of geometrothermodynamics to derive a fundamental thermodynamic equation, we construct a cosmological model in the framework of relativistic cosmology. In a first step, we describe a system without thermodynamic interaction, and show it to be equivalent to the standard ΛCDM paradigm. The second step includes thermodynamic interaction and produces a model consistent with the main features of inflation. With the proposed fundamental equation we are thus able to describe all the known epochs in the evolution of our Universe, starting from the inflationary phase.

  14. Modeling the long-term evolution of the primary damage in ferritic alloys using coarse-grained methods

    International Nuclear Information System (INIS)

    Becquart, C.S.; Barbu, A.; Bocquet, J.L.; Caturla, M.J.; Domain, C.; Fu, C.-C.; Golubov, S.I.; Hou, M.; Malerba, L.; Ortiz, C.J.; Souidi, A.; Stoller, R.E.

    2010-01-01

    Knowledge of the long-term evolution of the microstructure after introduction of primary damage is an essential ingredient in understanding mechanical property changes that occur during irradiation. Within the European integrated project 'PERFECT,' different techniques have been developed or improved to model microstructure evolution of Fe alloys under irradiation. This review paper aims to present the current state of the art of these techniques, as developed in the project, as well as the main results obtained.

  15. A Chemical Evolution Model for the Fornax Dwarf Spheroidal Galaxy

    Directory of Open Access Journals (Sweden)

    Yuan Zhen

    2016-01-01

    Full Text Available Fornax is the brightest Milky Way (MW dwarf spheroidal galaxy and its star formation history (SFH has been derived from observations. We estimate the time evolution of its gas mass and net inflow and outflow rates from the SFH usinga simple star formation law that relates the star formation rate to the gas mass. We present a chemical evolution model on a 2D mass grid with supernovae (SNe as sources of metal enrichment. We find that a key parameter controlling the enrichment is the mass Mx of the gas to mix with the ejecta from each SN. The choice of Mx depends on the evolution of SN remnants and on the global gas dynamics. It differs between the two types of SNe involved and between the periods before and after Fornax became an MW satellite at time t = tsat. Our results indicate that due to the global gas outflow at t > tsat, part of the ejecta from each SN may directly escape from Fornax. Sample results from our model are presented and compared with data.

  16. Firework Model: Time Dependent Spectral Evolution of GRB

    Science.gov (United States)

    Barbiellini, Guido; Longo, Francesco; Ghirlanda, G.; Celotti, A.; Bosnjak, Z.

    2004-09-01

    The energetics of the long duration GRB phenomenon is compared with models of a rotating BH in a strong magnetic field generated by an accreting torus. The GRB energy emission is attributed to magnetic field vacuum breakdown that gives origin to a e +/- fireball. Its subsequent evolution is hypothesized in analogy with the in-flight decay of an elementary particle. An anisotropy in the fireball propagation is thus naturally produced. The recent discovery in some GRB of an initial phase characterized by a thermal spectrum could be interpreted as the photon emission of the fireball photosphere when it becomes transparent. In particular, the temporal evolution of the emission can be explained as the effect of a radiative deceleration of the out-moving ejecta.

  17. Bayesian semiparametric regression models to characterize molecular evolution

    Directory of Open Access Journals (Sweden)

    Datta Saheli

    2012-10-01

    Full Text Available Abstract Background Statistical models and methods that associate changes in the physicochemical properties of amino acids with natural selection at the molecular level typically do not take into account the correlations between such properties. We propose a Bayesian hierarchical regression model with a generalization of the Dirichlet process prior on the distribution of the regression coefficients that describes the relationship between the changes in amino acid distances and natural selection in protein-coding DNA sequence alignments. Results The Bayesian semiparametric approach is illustrated with simulated data and the abalone lysin sperm data. Our method identifies groups of properties which, for this particular dataset, have a similar effect on evolution. The model also provides nonparametric site-specific estimates for the strength of conservation of these properties. Conclusions The model described here is distinguished by its ability to handle a large number of amino acid properties simultaneously, while taking into account that such data can be correlated. The multi-level clustering ability of the model allows for appealing interpretations of the results in terms of properties that are roughly equivalent from the standpoint of molecular evolution.

  18. Last interglacial temperature evolution – a model inter-comparison

    Directory of Open Access Journals (Sweden)

    P. Bakker

    2013-03-01

    Full Text Available There is a growing number of proxy-based reconstructions detailing the climatic changes that occurred during the last interglacial period (LIG. This period is of special interest, because large parts of the globe were characterized by a warmer-than-present-day climate, making this period an interesting test bed for climate models in light of projected global warming. However, mainly because synchronizing the different palaeoclimatic records is difficult, there is no consensus on a global picture of LIG temperature changes. Here we present the first model inter-comparison of transient simulations covering the LIG period. By comparing the different simulations, we aim at investigating the common signal in the LIG temperature evolution, investigating the main driving forces behind it and at listing the climate feedbacks which cause the most apparent inter-model differences. The model inter-comparison shows a robust Northern Hemisphere July temperature evolution characterized by a maximum between 130–125 ka BP with temperatures 0.3 to 5.3 K above present day. A Southern Hemisphere July temperature maximum, −1.3 to 2.5 K at around 128 ka BP, is only found when changes in the greenhouse gas concentrations are included. The robustness of simulated January temperatures is large in the Southern Hemisphere and the mid-latitudes of the Northern Hemisphere. For these regions maximum January temperature anomalies of respectively −1 to 1.2 K and −0.8 to 2.1 K are simulated for the period after 121 ka BP. In both hemispheres these temperature maxima are in line with the maximum in local summer insolation. In a number of specific regions, a common temperature evolution is not found amongst the models. We show that this is related to feedbacks within the climate system which largely determine the simulated LIG temperature evolution in these regions. Firstly, in the Arctic region, changes in the summer sea-ice cover control the evolution of LIG winter

  19. Quintom models with an equation of state crossing -1

    International Nuclear Information System (INIS)

    Zhao Wen; Zhang Yang

    2006-01-01

    In this paper, we investigate a kind of special quintom model, which is made of a quintessence field φ 1 and a phantom field φ 2 , and the potential function has the form of V(φ 1 2 -φ 2 2 ). This kind of quintom field can be separated into two kinds: the hessence model, which has the state of φ 1 2 >φ 2 2 , and the hantom model with the state φ 1 2 2 2 . We discuss the evolution of these models in the ω-ω ' plane (ω is the state equation of the dark energy, and ω ' is its time derivative in units of Hubble time), and find that according to ω>-1 or ' plane can be divided into four parts. The late time attractor solution, if existing, is always quintessencelike or Λ-like for hessence field, so the big rip does not exist. But for hantom field, its late time attractor solution can be phantomlike or Λ-like, and sometimes, the big rip is unavoidable. Then we consider two special cases: one is the hessence field with an exponential potential, and the other is with a power law potential. We investigate their evolution in the ω-ω ' plane. We also develop a theoretical method of constructing the hessence potential function directly from the effective equation-of-state function ω(z). We apply our method to five kinds of parametrizations of equation-of-state parameter, where ω crossing -1 can exist, and find they all can be realized. At last, we discuss the evolution of the perturbations of the quintom field, and find the perturbations of the quintom δ Q and the metric Φ are all finite even at the state of ω=-1 and ω ' ≠0

  20. Alignment and prediction of cis-regulatory modules based on a probabilistic model of evolution.

    Directory of Open Access Journals (Sweden)

    Xin He

    2009-03-01

    Full Text Available Cross-species comparison has emerged as a powerful paradigm for predicting cis-regulatory modules (CRMs and understanding their evolution. The comparison requires reliable sequence alignment, which remains a challenging task for less conserved noncoding sequences. Furthermore, the existing models of DNA sequence evolution generally do not explicitly treat the special properties of CRM sequences. To address these limitations, we propose a model of CRM evolution that captures different modes of evolution of functional transcription factor binding sites (TFBSs and the background sequences. A particularly novel aspect of our work is a probabilistic model of gains and losses of TFBSs, a process being recognized as an important part of regulatory sequence evolution. We present a computational framework that uses this model to solve the problems of CRM alignment and prediction. Our alignment method is similar to existing methods of statistical alignment but uses the conserved binding sites to improve alignment. Our CRM prediction method deals with the inherent uncertainties of binding site annotations and sequence alignment in a probabilistic framework. In simulated as well as real data, we demonstrate that our program is able to improve both alignment and prediction of CRM sequences over several state-of-the-art methods. Finally, we used alignments produced by our program to study binding site conservation in genome-wide binding data of key transcription factors in the Drosophila blastoderm, with two intriguing results: (i the factor-bound sequences are under strong evolutionary constraints even if their neighboring genes are not expressed in the blastoderm and (ii binding sites in distal bound sequences (relative to transcription start sites tend to be more conserved than those in proximal regions. Our approach is implemented as software, EMMA (Evolutionary Model-based cis-regulatory Module Analysis, ready to be applied in a broad biological context.

  1. Eco-genetic modeling of contemporary life-history evolution.

    Science.gov (United States)

    Dunlop, Erin S; Heino, Mikko; Dieckmann, Ulf

    2009-10-01

    We present eco-genetic modeling as a flexible tool for exploring the course and rates of multi-trait life-history evolution in natural populations. We build on existing modeling approaches by combining features that facilitate studying the ecological and evolutionary dynamics of realistically structured populations. In particular, the joint consideration of age and size structure enables the analysis of phenotypically plastic populations with more than a single growth trajectory, and ecological feedback is readily included in the form of density dependence and frequency dependence. Stochasticity and life-history trade-offs can also be implemented. Critically, eco-genetic models permit the incorporation of salient genetic detail such as a population's genetic variances and covariances and the corresponding heritabilities, as well as the probabilistic inheritance and phenotypic expression of quantitative traits. These inclusions are crucial for predicting rates of evolutionary change on both contemporary and longer timescales. An eco-genetic model can be tightly coupled with empirical data and therefore may have considerable practical relevance, in terms of generating testable predictions and evaluating alternative management measures. To illustrate the utility of these models, we present as an example an eco-genetic model used to study harvest-induced evolution of multiple traits in Atlantic cod. The predictions of our model (most notably that harvesting induces a genetic reduction in age and size at maturation, an increase or decrease in growth capacity depending on the minimum-length limit, and an increase in reproductive investment) are corroborated by patterns observed in wild populations. The predicted genetic changes occur together with plastic changes that could phenotypically mask the former. Importantly, our analysis predicts that evolutionary changes show little signs of reversal following a harvest moratorium. This illustrates how predictions offered by

  2. Manifestations of classical physics in the quantum evolution of correlated spin states in pulsed NMR experiments.

    Science.gov (United States)

    Ligare, Martin

    2016-05-01

    Multiple-pulse NMR experiments are a powerful tool for the investigation of molecules with coupled nuclear spins. The product operator formalism provides a way to understand the quantum evolution of an ensemble of weakly coupled spins in such experiments using some of the more intuitive concepts of classical physics and semi-classical vector representations. In this paper I present a new way in which to interpret the quantum evolution of an ensemble of spins. I recast the quantum problem in terms of mixtures of pure states of two spins whose expectation values evolve identically to those of classical moments. Pictorial representations of these classically evolving states provide a way to calculate the time evolution of ensembles of weakly coupled spins without the full machinery of quantum mechanics, offering insight to anyone who understands precession of magnetic moments in magnetic fields.

  3. Coherence Evolution and Transfer Supplemented by Sender's Initial-State Restoring

    Science.gov (United States)

    Fel'dman, E. B.; Zenchuk, A. I.

    2017-12-01

    The evolution of quantum coherences comes with a set of conservation laws provided that the Hamiltonian governing this evolution conserves the spin-excitation number. At that, coherences do not intertwist during the evolution. Using the transmission line and the receiver in the initial ground state we can transfer the coherences to the receiver without interaction between them, although the matrix elements contributing to each particular coherence intertwist in the receiver's state. Therefore we propose a tool based on the unitary transformation at the receiver side to untwist these elements and thus restore (at least partially) the structure of the sender's initial density matrix. A communication line with two-qubit sender and receiver is considered as an example of implementation of this technique.

  4. Functional State Modelling of Saccharomyces cerevisiae Cultivations

    Directory of Open Access Journals (Sweden)

    Iasen Hristozov

    2004-10-01

    Full Text Available The implementation of functional state approach for modelling of yeast cultivation is considered in this paper. This concept helps in monitoring and control of complex processes such as bioprocesses. Using of functional state modelling approach for fermentation processes aims to overcome the main disadvantage of using global process model, namely complex model structure and big number of model parameters. The main advantage of functional state modelling is that the parameters of each local model can be separately estimated from other local models parameters. The results achieved from batch, as well as from fed-batch, cultivations are presented.

  5. Chempy: A flexible chemical evolution model for abundance fitting. Do the Sun's abundances alone constrain chemical evolution models?

    Science.gov (United States)

    Rybizki, Jan; Just, Andreas; Rix, Hans-Walter

    2017-09-01

    Elemental abundances of stars are the result of the complex enrichment history of their galaxy. Interpretation of observed abundances requires flexible modeling tools to explore and quantify the information about Galactic chemical evolution (GCE) stored in such data. Here we present Chempy, a newly developed code for GCE modeling, representing a parametrized open one-zone model within a Bayesian framework. A Chempy model is specified by a set of five to ten parameters that describe the effective galaxy evolution along with the stellar and star-formation physics: for example, the star-formation history (SFH), the feedback efficiency, the stellar initial mass function (IMF), and the incidence of supernova of type Ia (SN Ia). Unlike established approaches, Chempy can sample the posterior probability distribution in the full model parameter space and test data-model matches for different nucleosynthetic yield sets. It is essentially a chemical evolution fitting tool. We straightforwardly extend Chempy to a multi-zone scheme. As an illustrative application, we show that interesting parameter constraints result from only the ages and elemental abundances of the Sun, Arcturus, and the present-day interstellar medium (ISM). For the first time, we use such information to infer the IMF parameter via GCE modeling, where we properly marginalize over nuisance parameters and account for different yield sets. We find that 11.6+ 2.1-1.6% of the IMF explodes as core-collapse supernova (CC-SN), compatible with Salpeter (1955, ApJ, 121, 161). We also constrain the incidence of SN Ia per 103M⊙ to 0.5-1.4. At the same time, this Chempy application shows persistent discrepancies between predicted and observed abundances for some elements, irrespective of the chosen yield set. These cannot be remedied by any variations of Chempy's parameters and could be an indication of missing nucleosynthetic channels. Chempy could be a powerful tool to confront predictions from stellar

  6. Adding geochemical and isotope tracers to models of hillslope evolution: valuable constraints or monumental headache?

    Science.gov (United States)

    Mudd, S. M.; Yoo, K.; Hurst, M. D.; Weinman, B. A.; Maher, K.

    2011-12-01

    Landscapes evolve through time, both in terms of their geomorphology and their geochemistry. Past studies have highlighted that topography suffers from the problem of equifinality: the topographic configuration of landscapes can be the result of many different, yet equally plausible, erosion histories. In hillslope soils the properties and chemistry of the soils themselves could provide additional constraints on landscape evolution. Here we present results from a combination of modelling and field studies that seek to quantify the co-evolution of hillslope morphology and the solid state chemistry of hillslope soils. The models follow large numbers of individual particles as they are entrained into a physically mobile soil layer, weathered, and accumulate isotopes such as 10Be and 21Ne. We demonstrate that multiple hillslope properties mitigate (but do not eliminate) the problem of equifinality and demonstrate the importance of accounting for individual particle residence times and ages in interpretation of both isotope and weathering data.

  7. Designing non-Hermitian dynamics for conservative state evolution on the Bloch sphere

    Science.gov (United States)

    Yu, Sunkyu; Piao, Xianji; Park, Namkyoo

    2018-03-01

    An evolution on the Bloch sphere is the fundamental state transition, including optical polarization controls and qubit operations. Conventional evolution of a polarization state or qubit is implemented within a closed system that automatically satisfies energy conservation from the Hermitian formalism. Although particular forms of static non-Hermitian Hamiltonians, such as parity-time-symmetric Hamiltonians, allow conservative states in an open system, the criteria for the energy conservation in a dynamical open system have not been fully explored. Here, we derive the condition of conservative state evolution in open-system dynamics and its inverse design method, by developing the non-Hermitian modification of the Larmor precession equation. We show that the geometrically designed locus on the Bloch sphere can be realized by different forms of dynamics, leading to the isolocus family of non-Hermitian dynamics. This increased degree of freedom allows the complementary phenomena of error-robust and highly sensitive evolutions on the Bloch sphere, which could be applicable to stable polarizers, quantum gates, and optimized sensors in dynamical open systems.

  8. On irreversible evolutions of two-level systems approaching coherent and squeezed states

    International Nuclear Information System (INIS)

    Jurco, B.; Tolar, J.

    1988-01-01

    The concepts of completely positive quantum dynamical semigroups and SU(2)-related generalized coherence and squeezing are used to investigate conditions for Markovian evolutions leading to coherent, intelligent, minimum-uncertainty and squeezed asymptotic stationary states in a 2-level system. (author). 10 refs

  9. Twentieth Century evolution of machining in the United States – An ...

    Indian Academy of Sciences (India)

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

    beginning of the Industrial Revolution in the late 1700's, virtually no ... expected that, by the middle of the 19th Century, as machine tools began to be manufactured .... Twentieth Century evolution of machining in the United States. 873. DESIGN ... Merchant M E 1961 The manufacturing system concept in production ...

  10. A finite element model for the quench front evolution problem

    International Nuclear Information System (INIS)

    Folescu, J.; Galeao, A.C.N.R.; Carmo, E.G.D. do.

    1985-01-01

    A model for the rewetting problem associated with the loss of coolant accident in a PWR reactor is proposed. A variational formulation for the time-dependent heat conduction problem on fuel rod cladding is used, and appropriate boundary conditions are assumed in order to simulate the thermal interaction between the fuel rod cladding and the fluid. A numerical procedure which uses the finite element method for the spatial discretization and a Crank-Nicolson-like method for the step-by-step integration is developed. Some numerical results are presented showing the quench front evolution and its stationary profile. (Author) [pt

  11. Generative Models in Deep Learning: Constraints for Galaxy Evolution

    Science.gov (United States)

    Turp, Maximilian Dennis; Schawinski, Kevin; Zhang, Ce; Weigel, Anna K.

    2018-01-01

    New techniques are essential to make advances in the field of galaxy evolution. Recent developments in the field of artificial intelligence and machine learning have proven that these tools can be applied to problems far more complex than simple image recognition. We use these purely data driven approaches to investigate the process of star formation quenching. We show that Variational Autoencoders provide a powerful method to forward model the process of galaxy quenching. Our results imply that simple changes in specific star formation rate and bulge to disk ratio cannot fully describe the properties of the quenched population.

  12. Modeling the Evolution of Female Meiotic Drive in Maize

    Directory of Open Access Journals (Sweden)

    David W. Hall

    2018-01-01

    Full Text Available Autosomal drivers violate Mendel’s law of segregation in that they are overrepresented in gametes of heterozygous parents. For drivers to be polymorphic within populations rather than fixing, their transmission advantage must be offset by deleterious effects on other fitness components. In this paper, we develop an analytical model for the evolution of autosomal drivers that is motivated by the neocentromere drive system found in maize. In particular, we model both the transmission advantage and deleterious fitness effects on seed viability, pollen viability, seed to adult survival mediated by maternal genotype, and seed to adult survival mediated by offspring genotype. We derive general, biologically intuitive conditions for the four most likely evolutionary outcomes and discuss the expected evolution of autosomal drivers given these conditions. Finally, we determine the expected equilibrium allele frequencies predicted by the model given recent estimates of fitness components for all relevant genotypes and show that the predicted equilibrium is within the range observed in maize land races for levels of drive at the low end of what has been observed.

  13. Early-state damage detection, characterization, and evolution using high-resolution computed tomography

    Science.gov (United States)

    Grandin, Robert John

    Safely using materials in high performance applications requires adequately understanding the mechanisms which control the nucleation and evolution of damage. Most of a material's operational life is spent in a state with noncritical damage, and, for example in metals only a small portion of its life falls within the classical Paris Law regime of crack growth. Developing proper structural health and prognosis models requires understanding the behavior of damage in these early stages within the material's life, and this early-stage damage occurs on length scales at which the material may be considered "granular'' in the sense that the discrete regions which comprise the whole are large enough to require special consideration. Material performance depends upon the characteristics of the granules themselves as well as the interfaces between granules. As a result, properly studying early-stage damage in complex, granular materials requires a means to characterize changes in the granules and interfaces. The granular-scale can range from tenths of microns in ceramics, to single microns in fiber-reinforced composites, to tens of millimeters in concrete. The difficulty of direct-study is often overcome by exhaustive testing of macro-scale damage caused by gross material loads and abuse. Such testing, for example optical or electron microscopy, destructive and further, is costly when used to study the evolution of damage within a material and often limits the study to a few snapshots. New developments in high-resolution computed tomography (HRCT) provide the necessary spatial resolution to directly image the granule length-scale of many materials. Successful application of HRCT with fiber-reinforced composites, however, requires extending the HRCT performance beyond current limits. This dissertation will discuss improvements made in the field of CT reconstruction which enable resolutions to be pushed to the point of being able to image the fiber-scale damage structures and

  14. Six-vertex model and Schramm-Loewner evolution

    Science.gov (United States)

    Kenyon, Richard; Miller, Jason; Sheffield, Scott; Wilson, David B.

    2017-05-01

    Square ice is a statistical mechanics model for two-dimensional ice, widely believed to have a conformally invariant scaling limit. We associate a Peano (space-filling) curve to a square ice configuration, and more generally to a so-called six-vertex model configuration, and argue that its scaling limit is a space-filling version of the random fractal curve SL E κ, Schramm-Loewner evolution with parameter κ , where 4 <κ ≤12 +8 √{2 } . For square ice, κ =12 . At the "free-fermion point" of the six-vertex model, κ =8 +4 √{3 } . These unusual values lie outside the classical interval 2 ≤κ ≤8 .

  15. Model Checking Multivariate State Rewards

    DEFF Research Database (Denmark)

    Nielsen, Bo Friis; Nielson, Flemming; Nielson, Hanne Riis

    2010-01-01

    We consider continuous stochastic logics with state rewards that are interpreted over continuous time Markov chains. We show how results from multivariate phase type distributions can be used to obtain higher-order moments for multivariate state rewards (including covariance). We also generalise...

  16. A mechano-biological model of multi-tissue evolution in bone

    Science.gov (United States)

    Frame, Jamie; Rohan, Pierre-Yves; Corté, Laurent; Allena, Rachele

    2017-12-01

    Successfully simulating tissue evolution in bone is of significant importance in predicting various biological processes such as bone remodeling, fracture healing and osseointegration of implants. Each of these processes involves in different ways the permanent or transient formation of different tissue types, namely bone, cartilage and fibrous tissues. The tissue evolution in specific circumstances such as bone remodeling and fracturing healing is currently able to be modeled. Nevertheless, it remains challenging to predict which tissue types and organization can develop without any a priori assumptions. In particular, the role of mechano-biological coupling in this selective tissue evolution has not been clearly elucidated. In this work, a multi-tissue model has been created which simultaneously describes the evolution of bone, cartilage and fibrous tissues. The coupling of the biological and mechanical factors involved in tissue formation has been modeled by defining two different tissue states: an immature state corresponding to the early stages of tissue growth and representing cell clusters in a weakly neo-formed Extra Cellular Matrix (ECM), and a mature state corresponding to well-formed connective tissues. This has allowed for the cellular processes of migration, proliferation and apoptosis to be described simultaneously with the changing ECM properties through strain driven diffusion, growth, maturation and resorption terms. A series of finite element simulations were carried out on idealized cantilever bending geometries. Starting from a tissue composition replicating a mid-diaphysis section of a long bone, a steady-state tissue formation was reached over a statically loaded period of 10,000 h (60 weeks). The results demonstrated that bone formation occurred in regions which are optimally physiologically strained. In two additional 1000 h bending simulations both cartilaginous and fibrous tissues were shown to form under specific geometrical and loading

  17. Phase-field modelling of microstructural evolution and properties

    Science.gov (United States)

    Zhu, Jingzhi

    As one of the most powerful techniques in computational materials science, the diffuse-interface phase-field model has been widely employed for simulating various meso-scale microstructural evolution processes. The main purpose of this thesis is to develop a quantitative phase-field model for predicting microstructures and properties in real alloy systems which can be linked to existing thermodynamic/kinetic databases and parameters obtained from experimental measurements or first-principle calculations. To achieve this goal; many factors involved in complicated real systems are investigated, many of which are often simplified or ignored in existing models, e.g. the dependence of diffusional atomic mobility and elastic constants on composition. Efficient numerical techniques must be developed to solve those partial differential equations that are involved in modelling microstructural evolutions and properties. In this thesis, different spectral methods were proposed for the time-dependent phase-field kinetic equations and diffusion equations. For solving the elastic equilibrium equation with the consideration of elastic inhomogeneity, a conjugate gradient method was utilized. The numerical approaches developed were generally found to be more accurate and efficient than conventional approach such as finite difference method. A composition-dependent Cahn-Hilliard equation was solved by using a semi-implicit Fourier-spectral method. It was shown that the morphological evolutions in bulk-diffusion-controlled coarsening and interface-diffusion-controlled developed similar patterns and scaling behaviors. For bulk-diffusion-controlled coarsening, a cubic growth law was obeyed in the scaling regime, whereas a fourth power growth law was observed for interface-diffusion-controlled coarsening. The characteristics of a microstructure under the influence of elastic energy depend on elastic properties such as elastic anisotropy, lattice mismatch, elastic inhomogeneity and

  18. Modeling Per Capita State Health Expenditure Variat...

    Data.gov (United States)

    U.S. Department of Health & Human Services — Modeling Per Capita State Health Expenditure Variation State-Level Characteristics Matter, published in Volume 3, Issue 4, of the Medicare and Medicaid Research...

  19. Modeling the Evolution of Beliefs Using an Attentional Focus Mechanism.

    Directory of Open Access Journals (Sweden)

    Dimitrije Marković

    2015-10-01

    Full Text Available For making decisions in everyday life we often have first to infer the set of environmental features that are relevant for the current task. Here we investigated the computational mechanisms underlying the evolution of beliefs about the relevance of environmental features in a dynamical and noisy environment. For this purpose we designed a probabilistic Wisconsin card sorting task (WCST with belief solicitation, in which subjects were presented with stimuli composed of multiple visual features. At each moment in time a particular feature was relevant for obtaining reward, and participants had to infer which feature was relevant and report their beliefs accordingly. To test the hypothesis that attentional focus modulates the belief update process, we derived and fitted several probabilistic and non-probabilistic behavioral models, which either incorporate a dynamical model of attentional focus, in the form of a hierarchical winner-take-all neuronal network, or a diffusive model, without attention-like features. We used Bayesian model selection to identify the most likely generative model of subjects' behavior and found that attention-like features in the behavioral model are essential for explaining subjects' responses. Furthermore, we demonstrate a method for integrating both connectionist and Bayesian models of decision making within a single framework that allowed us to infer hidden belief processes of human subjects.

  20. New Model of Evolution of Technologies and Prospects of Research With Using Big Data

    Directory of Open Access Journals (Sweden)

    Sergey Krichevsky

    2016-10-01

    Full Text Available In order to create the adequate technical picture of the world we need the new comprehension, the new models of evolution of technology and technosphere, and the new tools of perception, fixation and interpretation of the artefacts of the technical reality. A new interpretation of the notion «technological mode», which is the key in this article is suggested. Technological mode is the order of the existence and the activity of the society with the application of a number of mutually connected technologies, in the format of socio-techno-natural system, in the interaction with the environment, with the coverage of socio-eco-economic aspects. A new model of the evolution of technologies in the global paradigm of the global future and «green» development has been developed. The model shows: 1 the accelerated growth and the estimation of the total number of technologies; 2 1st - 7th technological modes (including the promising «green» as the rising levels of the integral technological way, inscribed in the Snooks-Panov’s hyperbolic curve, which reflects the process of evolution on the Earth with a singularity ~ in 2045 (forecast; 3 before-singular as well as post-singular migration options and global future; 4 a hypothetical post-singular 8th technological mode. As a new tool, it is proposed to use Big Data for the research of the nonlinear global process of evolution of technologies, technological modes, and the technosphere for the purpose of the analysis, forecast and management. The idea and the foundations of the concept of a new international mega-project «Big data for research of the evolution of technologies» are also stated.

  1. Entropy in the Tangled Nature Model of Evolution

    Directory of Open Access Journals (Sweden)

    Ty N. F. Roach

    2017-04-01

    Full Text Available Applications of entropy principles to evolution and ecology are of tantamount importance given the central role spatiotemporal structuring plays in both evolution and ecological succession. We obtain here a qualitative interpretation of the role of entropy in evolving ecological systems. Our interpretation is supported by mathematical arguments using simulation data generated by the Tangled Nature Model (TNM, a stochastic model of evolving ecologies. We define two types of configurational entropy and study their empirical time dependence obtained from the data. Both entropy measures increase logarithmically with time, while the entropy per individual decreases in time, in parallel with the growth of emergent structures visible from other aspects of the simulation. We discuss the biological relevance of these entropies to describe niche space and functional space of ecosystems, as well as their use in characterizing the number of taxonomic configurations compatible with different niche partitioning and functionality. The TNM serves as an illustrative example of how to calculate and interpret these entropies, which are, however, also relevant to real ecosystems, where they can be used to calculate the number of functional and taxonomic configurations that an ecosystem can realize.

  2. Heavy ion collision evolution modeling with ECHO-QGP

    Science.gov (United States)

    Rolando, V.; Inghirami, G.; Beraudo, A.; Del Zanna, L.; Becattini, F.; Chandra, V.; De Pace, A.; Nardi, M.

    2014-11-01

    We present a numerical code modeling the evolution of the medium formed in relativistic heavy ion collisions, ECHO-QGP. The code solves relativistic hydrodynamics in (3 + 1)D, with dissipative terms included within the framework of Israel-Stewart theory; it can work both in Minkowskian and in Bjorken coordinates. Initial conditions are provided through an implementation of the Glauber model (both Optical and Monte Carlo), while freezeout and particle generation are based on the Cooper-Frye prescription. The code is validated against several test problems and shows remarkable stability and accuracy with the combination of a conservative (shock-capturing) approach and the high-order methods employed. In particular it beautifully agrees with the semi-analytic solution known as Gubser flow, both in the ideal and in the viscous Israel-Stewart case, up to very large times and without any ad hoc tuning of the algorithm.

  3. A probabilistic model for the evolution of RNA structure

    Directory of Open Access Journals (Sweden)

    Holmes Ian

    2004-10-01

    Full Text Available Abstract Background For the purposes of finding and aligning noncoding RNA gene- and cis-regulatory elements in multiple-genome datasets, it is useful to be able to derive multi-sequence stochastic grammars (and hence multiple alignment algorithms systematically, starting from hypotheses about the various kinds of random mutation event and their rates. Results Here, we consider a highly simplified evolutionary model for RNA, called "The TKF91 Structure Tree" (following Thorne, Kishino and Felsenstein's 1991 model of sequence evolution with indels, which we have implemented for pairwise alignment as proof of principle for such an approach. The model, its strengths and its weaknesses are discussed with reference to four examples of functional ncRNA sequences: a riboswitch (guanine, a zipcode (nanos, a splicing factor (U4 and a ribozyme (RNase P. As shown by our visualisations of posterior probability matrices, the selected examples illustrate three different signatures of natural selection that are highly characteristic of ncRNA: (i co-ordinated basepair substitutions, (ii co-ordinated basepair indels and (iii whole-stem indels. Conclusions Although all three types of mutation "event" are built into our model, events of type (i and (ii are found to be better modeled than events of type (iii. Nevertheless, we hypothesise from the model's performance on pairwise alignments that it would form an adequate basis for a prototype multiple alignment and genefinding tool.

  4. The metastable dynamo model of stellar rotational evolution

    International Nuclear Information System (INIS)

    Brown, Timothy M.

    2014-01-01

    This paper introduces a new empirical model for the rotational evolution of Sun-like stars—those with surface convection zones and non-convective interior regions. Previous models do not match the morphology of observed (rotation period)-color diagrams, notably the existence of a relatively long-lived 'C-sequence' of fast rotators first identified by Barnes. This failure motivates the Metastable Dynamo Model (MDM) described here. The MDM posits that stars are born with their magnetic dynamos operating in a mode that couples very weakly to the stellar wind, so their (initially very short) rotation periods at first change little with time. At some point, this mode spontaneously and randomly changes to a strongly coupled mode, the transition occurring with a mass-dependent lifetime that is of the order of 100 Myr. I show that with this assumption, one can obtain good fits to observations of young clusters, particularly for ages of 150-200 Myr. Previous models and the MDM both give qualitative agreement with the morphology of the slower-rotating 'I-sequence' stars, but none of them have been shown to accurately reproduce the stellar-mass-dependent evolution of the I-sequence stars, especially for clusters older than a few hundred million years. I discuss observational experiments that can test aspects of the MDM, and speculate that the physics underlying the MDM may be related to other situations described in the literature, in which stellar dynamos may have a multi-modal character.

  5. Purity of Gaussian states: Measurement schemes and time evolution in noisy channels

    International Nuclear Information System (INIS)

    Paris, Matteo G.A.; Illuminati, Fabrizio; Serafini, Alessio; De Siena, Silvio

    2003-01-01

    We present a systematic study of the purity for Gaussian states of single-mode continuous variable systems. We prove the connection of purity to observable quantities for these states, and show that the joint measurement of two conjugate quadratures is necessary and sufficient to determine the purity at any time. The statistical reliability and the range of applicability of the proposed measurement scheme are tested by means of Monte Carlo simulated experiments. We then consider the dynamics of purity in noisy channels. We derive an evolution equation for the purity of general Gaussian states both in thermal and in squeezed thermal baths. We show that purity is maximized at any given time for an initial coherent state evolving in a thermal bath, or for an initial squeezed state evolving in a squeezed thermal bath whose asymptotic squeezing is orthogonal to that of the input state

  6. Atomic scale modeling of defect production and microstructure evolution in irradiated metals

    Energy Technology Data Exchange (ETDEWEB)

    Diaz de la Rubia, T.; Soneda, N.; Shimomura, Y. [Lawrence Livermore National Lab., CA (United States)] [and others

    1997-04-01

    Irradiation effects in materials depend in a complex way on the form of the as-produced primary damage state and its spatial and temporal evolution. Thus, while collision cascades produce defects on a time scale of tens of picosecond, diffusion occurs over much longer time scales, of the order of seconds, and microstructure evolution over even longer time scales. In this report the authors present work aimed at describing damage production and evolution in metals across all the relevant time and length scales. They discuss results of molecular dynamics simulations of displacement cascades in Fe and V. They show that interstitial clusters are produced in cascades above 5 keV, but not vacancy clusters. Next, they discuss the development of a kinetic Monte Carlo model that enables calculations of damage evolution over much longer time scales (1000`s of s) than the picosecond lifetime of the cascade. They demonstrate the applicability of the method by presenting predictions on the fraction of freely migrating defects in {alpha}Fe during irradiation at 600 K.

  7. Atomic scale modeling of defect production and microstructure evolution in irradiated metals

    International Nuclear Information System (INIS)

    Diaz de la Rubia, T.; Soneda, N.; Shimomura, Y.

    1997-01-01

    Irradiation effects in materials depend in a complex way on the form of the as-produced primary damage state and its spatial and temporal evolution. Thus, while collision cascades produce defects on a time scale of tens of picosecond, diffusion occurs over much longer time scales, of the order of seconds, and microstructure evolution over even longer time scales. In this report the authors present work aimed at describing damage production and evolution in metals across all the relevant time and length scales. They discuss results of molecular dynamics simulations of displacement cascades in Fe and V. They show that interstitial clusters are produced in cascades above 5 keV, but not vacancy clusters. Next, they discuss the development of a kinetic Monte Carlo model that enables calculations of damage evolution over much longer time scales (1000's of s) than the picosecond lifetime of the cascade. They demonstrate the applicability of the method by presenting predictions on the fraction of freely migrating defects in αFe during irradiation at 600 K

  8. Leader's opinion priority bounded confidence model for network opinion evolution

    Science.gov (United States)

    Zhu, Meixia; Xie, Guangqiang

    2017-08-01

    Aiming at the weight of trust someone given to participate in the interaction in Hegselmann-Krause's type consensus model is the same and virtual social networks among individuals with different level of education, personal influence, etc. For differences between agents, a novelty bounded confidence model was proposed with leader's opinion considered priority. Interaction neighbors can be divided into two kinds. The first kind is made up of "opinion leaders" group, another kind is made up of ordinary people. For different groups to give different weights of trust. We also analyzed the related characteristics of the new model under the symmetrical bounded confidence parameters and combined with the classical HK model were analyzed. Simulation experiment results show that no matter the network size and initial view is subject to uniform distribution or discrete distribution. We can control the "opinion-leader" good change the number of views and values, and even improve the convergence speed. Experiment also found that the choice of "opinion leaders" is not the more the better, the model well explain how the "opinion leader" in the process of the evolution of the public opinion play the role of the leader.

  9. A unifying model of genome evolution under parsimony.

    Science.gov (United States)

    Paten, Benedict; Zerbino, Daniel R; Hickey, Glenn; Haussler, David

    2014-06-19

    Parsimony and maximum likelihood methods of phylogenetic tree estimation and parsimony methods for genome rearrangements are central to the study of genome evolution yet to date they have largely been pursued in isolation. We present a data structure called a history graph that offers a practical basis for the analysis of genome evolution. It conceptually simplifies the study of parsimonious evolutionary histories by representing both substitutions and double cut and join (DCJ) rearrangements in the presence of duplications. The problem of constructing parsimonious history graphs thus subsumes related maximum parsimony problems in the fields of phylogenetic reconstruction and genome rearrangement. We show that tractable functions can be used to define upper and lower bounds on the minimum number of substitutions and DCJ rearrangements needed to explain any history graph. These bounds become tight for a special type of unambiguous history graph called an ancestral variation graph (AVG), which constrains in its combinatorial structure the number of operations required. We finally demonstrate that for a given history graph G, a finite set of AVGs describe all parsimonious interpretations of G, and this set can be explored with a few sampling moves. This theoretical study describes a model in which the inference of genome rearrangements and phylogeny can be unified under parsimony.

  10. Steady-State Process Modelling

    DEFF Research Database (Denmark)

    Cameron, Ian; Gani, Rafiqul

    2011-01-01

    illustrate the “equation oriented” approach as well as the “sequential modular” approach to solving complex flowsheets for steady state applications. The applications include the Williams-Otto plant, the hydrodealkylation (HDA) of toluene, conversion of ethylene to ethanol and a bio-ethanol process....

  11. Network evolution model for supply chain with manufactures as the core

    Science.gov (United States)

    Jiang, Dali; Fang, Ling; Yang, Jian; Li, Wu; Zhao, Jing

    2018-01-01

    Building evolution model of supply chain networks could be helpful to understand its development law. However, specific characteristics and attributes of real supply chains are often neglected in existing evolution models. This work proposes a new evolution model of supply chain with manufactures as the core, based on external market demand and internal competition-cooperation. The evolution model assumes the external market environment is relatively stable, considers several factors, including specific topology of supply chain, external market demand, ecological growth and flow conservation. The simulation results suggest that the networks evolved by our model have similar structures as real supply chains. Meanwhile, the influences of external market demand and internal competition-cooperation to network evolution are analyzed. Additionally, 38 benchmark data sets are applied to validate the rationality of our evolution model, in which, nine manufacturing supply chains match the features of the networks constructed by our model. PMID:29370201

  12. Network evolution model for supply chain with manufactures as the core.

    Science.gov (United States)

    Fang, Haiyang; Jiang, Dali; Yang, Tinghong; Fang, Ling; Yang, Jian; Li, Wu; Zhao, Jing

    2018-01-01

    Building evolution model of supply chain networks could be helpful to understand its development law. However, specific characteristics and attributes of real supply chains are often neglected in existing evolution models. This work proposes a new evolution model of supply chain with manufactures as the core, based on external market demand and internal competition-cooperation. The evolution model assumes the external market environment is relatively stable, considers several factors, including specific topology of supply chain, external market demand, ecological growth and flow conservation. The simulation results suggest that the networks evolved by our model have similar structures as real supply chains. Meanwhile, the influences of external market demand and internal competition-cooperation to network evolution are analyzed. Additionally, 38 benchmark data sets are applied to validate the rationality of our evolution model, in which, nine manufacturing supply chains match the features of the networks constructed by our model.

  13. Network evolution model for supply chain with manufactures as the core.

    Directory of Open Access Journals (Sweden)

    Haiyang Fang

    Full Text Available Building evolution model of supply chain networks could be helpful to understand its development law. However, specific characteristics and attributes of real supply chains are often neglected in existing evolution models. This work proposes a new evolution model of supply chain with manufactures as the core, based on external market demand and internal competition-cooperation. The evolution model assumes the external market environment is relatively stable, considers several factors, including specific topology of supply chain, external market demand, ecological growth and flow conservation. The simulation results suggest that the networks evolved by our model have similar structures as real supply chains. Meanwhile, the influences of external market demand and internal competition-cooperation to network evolution are analyzed. Additionally, 38 benchmark data sets are applied to validate the rationality of our evolution model, in which, nine manufacturing supply chains match the features of the networks constructed by our model.

  14. Numerical Modeling of Large-Scale Rocky Coastline Evolution

    Science.gov (United States)

    Limber, P.; Murray, A. B.; Littlewood, R.; Valvo, L.

    2008-12-01

    Seventy-five percent of the world's ocean coastline is rocky. On large scales (i.e. greater than a kilometer), many intertwined processes drive rocky coastline evolution, including coastal erosion and sediment transport, tectonics, antecedent topography, and variations in sea cliff lithology. In areas such as California, an additional aspect of rocky coastline evolution involves submarine canyons that cut across the continental shelf and extend into the nearshore zone. These types of canyons intercept alongshore sediment transport and flush sand to abyssal depths during periodic turbidity currents, thereby delineating coastal sediment transport pathways and affecting shoreline evolution over large spatial and time scales. How tectonic, sediment transport, and canyon processes interact with inherited topographic and lithologic settings to shape rocky coastlines remains an unanswered, and largely unexplored, question. We will present numerical model results of rocky coastline evolution that starts with an immature fractal coastline. The initial shape is modified by headland erosion, wave-driven alongshore sediment transport, and submarine canyon placement. Our previous model results have shown that, as expected, an initial sediment-free irregularly shaped rocky coastline with homogeneous lithology will undergo smoothing in response to wave attack; headlands erode and mobile sediment is swept into bays, forming isolated pocket beaches. As this diffusive process continues, pocket beaches coalesce, and a continuous sediment transport pathway results. However, when a randomly placed submarine canyon is introduced to the system as a sediment sink, the end results are wholly different: sediment cover is reduced, which in turn increases weathering and erosion rates and causes the entire shoreline to move landward more rapidly. The canyon's alongshore position also affects coastline morphology. When placed offshore of a headland, the submarine canyon captures local sediment

  15. Time Evolution Of The Wigner Function In Discrete Quantum Phase Space For A Soluble Quasi-spin Model

    CERN Document Server

    Galetti, D

    2000-01-01

    Summary: The discrete phase space approach to quantum mechanics of degrees of freedom without classical counterparts is applied to the many-fermions/quasi-spin Lipkin model. The Wigner function is written for some chosen states associated to discrete angle and angular momentum variables, and the time evolution is numerically calculated using the discrete von Neumann-Liouville equation. Direct evidences in the time evolution of the Wigner function are extracted that identify a tunnelling effect. A connection with an $SU(2)$-based semiclassical continuous approach to the Lipkin model is also presented.

  16. Numerical simulations of oscillating soliton stars: Excited states in spherical symmetry and ground state evolutions in 3D

    International Nuclear Information System (INIS)

    Balakrishna, Jayashree; Bondarescu, Ruxandra; Daues, Gregory; Bondarescu, Mihai

    2008-01-01

    Excited state soliton stars are studied numerically for the first time. The stability of spherically symmetric S-branch excited state oscillatons under radial perturbations is investigated using a 1D code. We find that these stars are inherently unstable either migrating to the ground state or collapsing to black holes. Higher excited state configurations are observed to cascade through intermediate excited states during their migration to the ground state. This is similar to excited state boson stars [J. Balakrishna, E. Seidel, and W.-M. Suen, Phys. Rev. D 58, 104004 (1998).]. Ground state oscillatons are then studied in full 3D numerical relativity. Finding the appropriate gauge condition for the dynamic oscillatons is much more challenging than in the case of boson stars. Different slicing conditions are explored, and a customized gauge condition that approximates polar slicing in spherical symmetry is implemented. Comparisons with 1D results and convergence tests are performed. The behavior of these stars under small axisymmetric perturbations is studied and gravitational waveforms are extracted. We find that the gravitational waves damp out on a short time scale, enabling us to obtain the complete waveform. This work is a starting point for the evolution of real scalar field systems with arbitrary symmetries

  17. STATE AID EVOLUTION OVERVIEW IN EUROPEAN UNION CONTEXT DURING THE PERIOD 2007-2012

    Directory of Open Access Journals (Sweden)

    Anca D.B., DODESCU

    2014-11-01

    Full Text Available According to the European Union point of view, the fundamental principle of state aid is to ensure that inside the single market, competition is not distorted. In this context, by exception state aid can be justified when they contribute to achieving EU's social and economic goals. This may take place when market forces obstruct the achieving of the proposed objectives or permit their achieving on unacceptable long terms and costs. This article is structured in four parts, focusing on European Union's vision regarding state aid measures. The first part of the article refers to the general context of state aid in EU. The second part of the article tries to define this concept according to European Commission point of view and also studies the state aid information provided by the EU, through its benchmarking instrument regarding state aid expenditure called State Aid Scoreboard. The third part of the article mainly presents the EU state aid evolution during the period 2007 - 2012 and establishes a methodological point of view in order to classify and divide state aid in two main categories: non-crisis state aid and crisis state aid, with the purpose of avoiding the distortion trends regarding state aid expenditure granted for the financial sector. This part of the article also presents different types of state aid at EU27 level and granted by the selected member states (Romania, Hungary, Bulgaria and Germany between 2007 and 2012 and also analysis horizontal aid, sectorial aid and state aid during the economic crisis 2008 - 2012, referring to recapitalization and asset relief measures and guarantees and liquidity measures. The last part of the article presents the conclusions and also states certain recommendations regarding EU state aid practices, based on the results obtained.

  18. Model Checking Infinite-State Markov Chains

    NARCIS (Netherlands)

    Remke, Anne Katharina Ingrid; Haverkort, Boudewijn R.H.M.; Cloth, L.

    2004-01-01

    In this paper algorithms for model checking CSL (continuous stochastic logic) against infinite-state continuous-time Markov chains of so-called quasi birth-death type are developed. In doing so we extend the applicability of CSL model checking beyond the recently proposed case for finite-state

  19. Modelling magnetic laminations under arbitrary starting state and flux waveform

    International Nuclear Information System (INIS)

    Bottauscio, Oriano; Chiampi, Mario; Ragusa, Carlo

    2005-01-01

    A numerical model able to predict the behaviour of a magnetic sheet under arbitrary supply conditions has been developed. The electromagnetic field problem is formulated in terms of an electric vector potential, which provides the magnetic field strength evolution. The hysteretic behaviour of the material is represented through the dynamic Preisach model where the activation law of the bi-state operators is modified in order to guarantee a smooth response. The problem has been solved through a time step procedure using the fixed Point technique for handling nonlinearity. The model has been validated by comparison with suitable experiments and it is applied to the investigation of the influence of the materials' starting state on the magnetic behaviour

  20. Unified model for vortex-string network evolution

    International Nuclear Information System (INIS)

    Martins, C.J.A.P.; Moore, J.N.; Shellard, E.P.S.

    2004-01-01

    We describe and numerically test the velocity-dependent one-scale string evolution model, a simple analytic approach describing a string network with the averaged correlation length and velocity. We show that it accurately reproduces the large-scale behavior (in particular the scaling laws) of numerical simulations of both Goto-Nambu and field theory string networks. We explicitly demonstrate the relation between the high-energy physics approach and the damped and nonrelativistic limits which are relevant for condensed matter physics. We also reproduce experimental results in this context and show that the vortex-string density is significantly reduced by loop production, an effect not included in the usual 'coarse-grained' approach

  1. A process model for the heat-affected zone microstructure evolution in duplex stainless steel weldments: Part I. the model

    Science.gov (United States)

    Hemmer, H.; Grong, Ø.

    1999-11-01

    The present investigation is concerned with modeling of the microstructure evolution in duplex stainless steels under thermal conditions applicable to welding. The important reactions that have been modeled are the dissolution of austenite during heating, subsequent grain growth in the delta ferrite regime, and finally, the decomposition of the delta ferrite to austenite during cooling. As a starting point, a differential formulation of the underlying diffusion problem is presented, based on the internal-state variable approach. These solutions are later manipulated and expressed in terms of the Scheil integral in the cases where the evolution equation is separable or can be made separable by a simple change of variables. The models have then been applied to describe the heat-affected zone microstructure evolution during both thick-plate and thin-plate welding of three commercial duplex stainless steel grades: 2205, 2304, and 2507. The results may conveniently be presented in the form of novel process diagrams, which display contours of constant delta ferrite grain size along with information about dissolution and reprecipitation of austenite for different combinations of weld input energy and peak temperature. These diagrams are well suited for quantitative readings and illustrate, in a condensed manner, the competition between the different variables that lead to structural changes during welding of duplex stainless steels.

  2. A modified Lotka-Volterra model for the evolution of coordinate symbiosis in energy enterprise

    Science.gov (United States)

    Zhou, Li; Wang, Teng; Lyu, Xiaohuan; Yu, Jing

    2018-02-01

    Recent developments in energy markets make the operating industries more dynamic and complex, and energy enterprises cooperate more closely in the industrial chain and symbiosis. In order to further discuss the evolution of coordinate symbiosis in energy enterprises, a modified Lotka-Volterra equation is introduced to develop a symbiosis analysis model of energy groups. According to the equilibrium and stability analysis, a conclusion is obtained that if the upstream energy group and the downstream energy group are in symbiotic state, the growth of their utility will be greater than their independent value. Energy enterprises can get mutual benefits and positive promotions in industrial chain by their cooperation.

  3. Competing feedbacks drive state transitions during initial catchment evolution: Examples from post-mining landscape and ecosystems evolution

    Science.gov (United States)

    Hinz, Christoph; Wolfgang, Schaaf; Werner, Gerwin

    2014-05-01

    Within the context of severely disturbed landscapes with little or no ecological memory, such as post-mining landscapes, we propose a simple framework that explains the catchment evolution as a result of competing feedbacks influenced by the initial conditions and the atmospheric drivers such as rainfall intermittency and intensity. The first stage of the evolution is dominated by abiotic feedbacks triggered by rainfall and subsequent fluid flow causing particle mobilisation on the surface and in the subsurface leading to flow concentration or in some instances to densification of surface and subsurface substrates. Subsequently, abiotic-biotic feedbacks start to compete in the sense that biological activity generally stabilizes substrate by preventing particle mobilisation and hence contribute to converting the substrate to a habitat. We suggest that these competing feedbacks may generate alternative stable states in particular under semi-arid and arid climatic conditions, while in temperate often energy limited environments biological process "outcompete" abiotic processes leading to a stable state, in particular from the water balance point of view for comparable geomorphic situations. To illustrate this framework, we provide examples from post-mining landscapes, in which soil, water and vegetation was monitored. In case of arid regions in Australia, we provide evidence that the initial conditions of a mine waste disposal "locked" the system into a state that was limited by water and nutrient storage capacity while at the same time it was stable from a geomorphic point of view for the observation period. The cause of the system to be locked in, is the very high hydraulic conductivity of the substrate, that has not undergone any changes during the first years. In contrast to this case study, we illustrate how this framework explains the evolution of an artificial catchment (Hühnerwasser Catchment) in Lusatia (150 km southeast of Berlin, Germany). During the

  4. Evolution of the squeezing-enhanced vacuum state in the amplitude dissipative channel

    Science.gov (United States)

    Ren, Gang; Du, Jian-ming; Zhang, Wen-hai

    2018-05-01

    We study the evolution of the squeezing-enhanced vacuum state (SEVS) in the amplitude dissipative channel by using the two-mode entangled state in the Fock space and Kraus operator. The explicit formulation of the output state is also given. It is found that the output state does not exhibit sub-Poissonian behavior for the nonnegative value of the Mandel's Q-parameters in a wide range of values of squeezing parameter and dissipation factor. It is interesting to see that second-order correlation function is independent of the dissipation factor. However, the photon-number distribution of the output quantum state shows remarkable oscillations with respect to the dissipation factor. The shape of Wigner function and the degree of squeezing show that the initial SEVS is dissipated by the amplitude dissipative channel.

  5. Parameter extraction of different fuel cell models with transferred adaptive differential evolution

    International Nuclear Information System (INIS)

    Gong, Wenyin; Yan, Xuesong; Liu, Xiaobo; Cai, Zhihua

    2015-01-01

    To improve the design and control of FC (fuel cell) models, it is important to extract their unknown parameters. Generally, the parameter extraction problems of FC models can be transformed as nonlinear and multi-variable optimization problems. To extract the parameters of different FC models exactly and fast, in this paper, we propose a transferred adaptive DE (differential evolution) framework, in which the successful parameters of the adaptive DE solving previous problems are properly transferred to solve new optimization problems in the similar problem-domains. Based on this framework, an improved adaptive DE method (TRADE, in short) is presented as an illustration. To verify the performance of our proposal, TRADE is used to extract the unknown parameters of two types of fuel cell models, i.e., PEMFC (proton exchange membrane fuel cell) and SOFC (solid oxide fuel cell). The results of TRADE are also compared with those of other state-of-the-art EAs (evolutionary algorithms). Even though the modification is very simple, the results indicate that TRADE can extract the parameters of both PEMFC and SOFC models exactly and fast. Moreover, the V–I characteristics obtained by TRADE agree well with the simulated and experimental data in all cases for both types of fuel cell models. Also, it improves the performance of the original adaptive DE significantly in terms of both the quality of final solutions and the convergence speed in all cases. Additionally, TRADE is able to provide better results compared with other EAs. - Highlights: • A framework of transferred adaptive differential evolution is proposed. • Based on the framework, an improved differential evolution (TRADE) is presented. • TRADE obtains very promising results to extract the parameters of PEMFC and SOFC models

  6. A coarse grained description of time evolution: Irreversible state reduction and time-energy relation

    International Nuclear Information System (INIS)

    Bonifacio, R.; Milan Univ.

    1983-05-01

    We show that a proper coarse-grained description of time evolution leads to a finite difference equation with step tau for the density operator. This implies state reduction to the diagonal form in the energy representation and a quasi ergodic behaviour of quantum mechanical ensemble averages. An intrinsic time-energy relation tauΔE>=(h/2π)/2 is proposed, and its equivalence to a time quantization is discussed. (author)

  7. Dynamics of second order in time evolution equations with state-dependent delay

    Czech Academy of Sciences Publication Activity Database

    Chueshov, I.; Rezunenko, Oleksandr

    123-124, č. 1 (2015), s. 126-149 ISSN 0362-546X R&D Projects: GA ČR GAP103/12/2431 Institutional support: RVO:67985556 Keywords : Second order evolution equations * State dependent delay * Nonlinear plate * Finite-dimensional attractor Subject RIV: BD - Theory of Information Impact factor: 1.125, year: 2015 http://library.utia.cas.cz/separaty/2015/AS/rezunenko-0444708.pdf

  8. 3DXRD characterization and modeling of solid-state transformation processes

    DEFF Research Database (Denmark)

    Juul Jensen, Dorte; Offerman, S.E.; Sietsma, J.

    2008-01-01

    of metallic microstructures with much more detail than hitherto possible. Among these modeling activities are three-dimensional (3D) geometric modeling, 3D molecular dynamics modeling, 3D phase-field modeling, two-dimensional (2D) cellular automata, and 2D Monte Carlo simulations....... data valuable for validation of various models of microstructural evolution is discussed, Examples of 3DXRD measurements related to recrystallization and to solid-state phase transformations in metals are described. 3DXRD measurements have led to new modeling activity predicting the evolution...

  9. Steady state HNG combustion modeling

    Energy Technology Data Exchange (ETDEWEB)

    Louwers, J.; Gadiot, G.M.H.J.L. [TNO Prins Maurits Lab., Rijswijk (Netherlands); Brewster, M.Q. [Univ. of Illinois, Urbana, IL (United States); Son, S.F. [Los Alamos National Lab., NM (United States); Parr, T.; Hanson-Parr, D. [Naval Air Warfare Center, China Lake, CA (United States)

    1998-04-01

    Two simplified modeling approaches are used to model the combustion of Hydrazinium Nitroformate (HNF, N{sub 2}H{sub 5}-C(NO{sub 2}){sub 3}). The condensed phase is treated by high activation energy asymptotics. The gas phase is treated by two limit cases: the classical high activation energy, and the recently introduced low activation energy approach. This results in simplification of the gas phase energy equation, making an (approximate) analytical solution possible. The results of both models are compared with experimental results of HNF combustion. It is shown that the low activation energy approach yields better agreement with experimental observations (e.g. regression rate and temperature sensitivity), than the high activation energy approach.

  10. Recent evolution of theoretical models in inner shell photoionization

    International Nuclear Information System (INIS)

    Combet Farnoux, F.

    1978-01-01

    This paper is a brief review of various atomic theoretical models recently developed to calculate photoionization cross sections in the low energy range (from the far ultraviolet to the soft X ray region). For both inner and outer shells concerned, we emphasize the necessity to go beyond the independent particle models by means of the introduction of correlation effects in both initial and final states. The basic physical ideas of as elaborated models as Random Phase Approximation with exchange, Many Body Perturbation Theory and R matrix Theory are outlined and summarized. As examples, the results of some calculations are shown and compared with experiment

  11. Modeling of Microstructure Evolution in Austenitic Stainless Steels Irradiated Under Light Water Reactor Conditions

    International Nuclear Information System (INIS)

    Gan, J.; Stoller, R.E.; Was, G.S.

    1998-01-01

    A model for the development of microstructure during irradiation in fast reactors has been adapted for light water reactor (LWR) irradiation conditions (275 approximately 325 C, up to approximately10 dpa). The original model was based on the rate-theory, and included descriptions of the evolution of both dislocation loops and cavities. The model was modified by introducing in-cascade interstitial clustering, a term to account for the dose dependence of this clustering, and mobility of interstitial clusters. The purpose of this work was to understand microstructural development under LWR irradiation with a focus on loop nucleation and saturation of loop density. It was demonstrated that in-cascade interstitial clustering dominates loop nucleation in neutron irradiation in LWRS. Furthermore it was shown that the dose dependence of in-cascade interstitial clustering is needed to account for saturation behavior as commonly observed. Both quasi-steady-state (QSS) and non-steady-state (NSS) solutions to the rate equations were obtained. The difference between QSS and NSS treatments in the calculation of defect concentration is reduced at LWR temperature when in-cascade interstitial clustering dominates loop nucleation. The mobility of interstitial clusters was also investigated and its impact on loop density is to reduce the nucleation term. The ultimate goal of this study is to combine the evolution of microstructure and microchemistry together to account for the radiation damage in austenitic stainless steels

  12. Spatial Models of Prebiotic Evolution: Soup Before Pizza?

    Science.gov (United States)

    Scheuring, István; Czárán, Tamás; Szabó, Péter; Károlyi, György; Toroczkai, Zoltán

    2003-10-01

    The problem of information integration and resistance to the invasion of parasitic mutants in prebiotic replicator systems is a notorious issue of research on the origin of life. Almost all theoretical studies published so far have demonstrated that some kind of spatial structure is indispensable for the persistence and/or the parasite resistance of any feasible replicator system. Based on a detailed critical survey of spatial models on prebiotic information integration, we suggest a possible scenario for replicator system evolution leading to the emergence of the first protocells capable of independent life. We show that even the spatial versions of the hypercycle model are vulnerable to selfish parasites in heterogeneous habitats. Contrary, the metabolic system remains persistent and coexistent with its parasites both on heterogeneous surfaces and in chaotically mixing flowing media. Persistent metabolic parasites can be converted to metabolic cooperators, or they can gradually obtain replicase activity. Our simulations show that, once replicase activity emerged, a gradual and simultaneous evolutionary improvement of replicase functionality (speed and fidelity) and template efficiency is possible only on a surface that constrains the mobility of macromolecule replicators. Based on the results of the models reviewed, we suggest that open chaotic flows (`soup') and surface dynamics (`pizza') both played key roles in the sequence of evolutionary events ultimately concluding in the appearance of the first living cell on Earth.

  13. Generalized Bell states map physical systems’ quantum evolution into a grammar for quantum information processing

    Science.gov (United States)

    Delgado, Francisco

    2017-12-01

    Quantum information processing should be generated through control of quantum evolution for physical systems being used as resources, such as superconducting circuits, spinspin couplings in ions and artificial anyons in electronic gases. They have a quantum dynamics which should be translated into more natural languages for quantum information processing. On this terrain, this language should let to establish manipulation operations on the associated quantum information states as classical information processing does. This work shows how a kind of processing operations can be settled and implemented for quantum states design and quantum processing for systems fulfilling a SU(2) reduction in their dynamics.

  14. Metal-Matrix Composites and Porous Materials: Constitute Models, Microstructure Evolution and Applications

    National Research Council Canada - National Science Library

    Castafieda, P

    2000-01-01

    Constitutive models were developed and implemented numerically to account for the evolution of microstructure and anisotropy in finite-deformation processes involving porous and composite materials...

  15. Sub-State Actors and Leadership in the Evolution of the African State

    National Research Council Canada - National Science Library

    Tall, Samba

    1998-01-01

    .... Understanding the root causes of the mutations occurring in today's African states will help to build legitimacy for future Internal Security Assistance Programs and Military Operations Other Than War...

  16. On rate-state and Coulomb failure models

    Science.gov (United States)

    Gomberg, J.; Beeler, N.; Blanpied, M.

    2000-01-01

    We examine the predictions of Coulomb failure stress and rate-state frictional models. We study the change in failure time (clock advance) Δt due to stress step perturbations (i.e., coseismic static stress increases) added to "background" stressing at a constant rate (i.e., tectonic loading) at time t0. The predictability of Δt implies a predictable change in seismicity rate r(t)/r0, testable using earthquake catalogs, where r0 is the constant rate resulting from tectonic stressing. Models of r(t)/r0, consistent with general properties of aftershock sequences, must predict an Omori law seismicity decay rate, a sequence duration that is less than a few percent of the mainshock cycle time and a return directly to the background rate. A Coulomb model requires that a fault remains locked during loading, that failure occur instantaneously, and that Δt is independent of t0. These characteristics imply an instantaneous infinite seismicity rate increase of zero duration. Numerical calculations of r(t)/r0 for different state evolution laws show that aftershocks occur on faults extremely close to failure at the mainshock origin time, that these faults must be "Coulomb-like," and that the slip evolution law can be precluded. Real aftershock population characteristics also may constrain rate-state constitutive parameters; a may be lower than laboratory values, the stiffness may be high, and/or normal stress may be lower than lithostatic. We also compare Coulomb and rate-state models theoretically. Rate-state model fault behavior becomes more Coulomb-like as constitutive parameter a decreases relative to parameter b. This is because the slip initially decelerates, representing an initial healing of fault contacts. The deceleration is more pronounced for smaller a, more closely simulating a locked fault. Even when the rate-state Δt has Coulomb characteristics, its magnitude may differ by some constant dependent on b. In this case, a rate-state model behaves like a modified

  17. EARLY DYNAMICAL EVOLUTION OF THE SOLAR SYSTEM: PINNING DOWN THE INITIAL CONDITIONS OF THE NICE MODEL

    International Nuclear Information System (INIS)

    Batygin, Konstantin; Brown, Michael E.

    2010-01-01

    In the recent years, the 'Nice' model of solar system formation has attained an unprecedented level of success in reproducing much of the observed orbital architecture of the solar system by evolving the planets to their current locations from a more compact configuration. Within the context of this model, the formation of the classical Kuiper Belt requires a phase during which the ice giants have a high eccentricity. An outstanding question of this model is the initial configuration from which the solar system started out. Recent work has shown that multi-resonant initial conditions can serve as good candidates, as they naturally prevent vigorous type-II migration. In this paper, we use analytical arguments, as well as self-consistent numerical N-body simulations to identify fully resonant initial conditions, whose dynamical evolution is characterized by an eccentric phase of the ice giants, as well as planetary scattering. We find a total of eight such initial conditions. Four of these primordial states are compatible with the canonical 'Nice' model, while the others imply slightly different evolutions. The results presented here should prove useful in further development of a comprehensive model for solar system formation.

  18. Beans (Phaseolus ssp.) as a Model for Understanding Crop Evolution

    Science.gov (United States)

    Bitocchi, Elena; Rau, Domenico; Bellucci, Elisa; Rodriguez, Monica; Murgia, Maria L.; Gioia, Tania; Santo, Debora; Nanni, Laura; Attene, Giovanna; Papa, Roberto

    2017-01-01

    Here, we aim to provide a comprehensive and up-to-date overview of the most significant outcomes in the literature regarding the origin of Phaseolus genus, the geographical distribution of the wild species, the domestication process, and the wide spread out of the centers of origin. Phaseolus can be considered as a unique model for the study of crop evolution, and in particular, for an understanding of the convergent phenotypic evolution that occurred under domestication. The almost unique situation that characterizes the Phaseolus genus is that five of its ∼70 species have been domesticated (i.e., Phaseolus vulgaris, P. coccineus, P. dumosus, P. acutifolius, and P. lunatus), and in addition, for P. vulgaris and P. lunatus, the wild forms are distributed in both Mesoamerica and South America, where at least two independent and isolated episodes of domestication occurred. Thus, at least seven independent domestication events occurred, which provides the possibility to unravel the genetic basis of the domestication process not only among species of the same genus, but also between gene pools within the same species. Along with this, other interesting features makes Phaseolus crops very useful in the study of evolution, including: (i) their recent divergence, and the high level of collinearity and synteny among their genomes; (ii) their different breeding systems and life history traits, from annual and autogamous, to perennial and allogamous; and (iii) their adaptation to different environments, not only in their centers of origin, but also out of the Americas, following their introduction and wide spread through different countries. In particular for P. vulgaris this resulted in the breaking of the spatial isolation of the Mesoamerican and Andean gene pools, which allowed spontaneous hybridization, thus increasing of the possibility of novel genotypes and phenotypes. This knowledge that is associated to the genetic resources that have been conserved ex situ and in

  19. Updating of states in operational hydrological models

    Science.gov (United States)

    Bruland, O.; Kolberg, S.; Engeland, K.; Gragne, A. S.; Liston, G.; Sand, K.; Tøfte, L.; Alfredsen, K.

    2012-04-01

    Operationally the main purpose of hydrological models is to provide runoff forecasts. The quality of the model state and the accuracy of the weather forecast together with the model quality define the runoff forecast quality. Input and model errors accumulate over time and may leave the model in a poor state. Usually model states can be related to observable conditions in the catchment. Updating of these states, knowing their relation to observable catchment conditions, influence directly the forecast quality. Norway is internationally in the forefront in hydropower scheduling both on short and long terms. The inflow forecasts are fundamental to this scheduling. Their quality directly influence the producers profit as they optimize hydropower production to market demand and at the same time minimize spill of water and maximize available hydraulic head. The quality of the inflow forecasts strongly depends on the quality of the models applied and the quality of the information they use. In this project the focus has been to improve the quality of the model states which the forecast is based upon. Runoff and snow storage are two observable quantities that reflect the model state and are used in this project for updating. Generally the methods used can be divided in three groups: The first re-estimates the forcing data in the updating period; the second alters the weights in the forecast ensemble; and the third directly changes the model states. The uncertainty related to the forcing data through the updating period is due to both uncertainty in the actual observation and to how well the gauging stations represent the catchment both in respect to temperatures and precipitation. The project looks at methodologies that automatically re-estimates the forcing data and tests the result against observed response. Model uncertainty is reflected in a joint distribution of model parameters estimated using the Dream algorithm.

  20. Models of microbiome evolution incorporating host and microbial selection.

    Science.gov (United States)

    Zeng, Qinglong; Wu, Steven; Sukumaran, Jeet; Rodrigo, Allen

    2017-09-25

    Numerous empirical studies suggest that hosts and microbes exert reciprocal selective effects on their ecological partners. Nonetheless, we still lack an explicit framework to model the dynamics of both hosts and microbes under selection. In a previous study, we developed an agent-based forward-time computational framework to simulate the neutral evolution of host-associated microbial communities in a constant-sized, unstructured population of hosts. These neutral models allowed offspring to sample microbes randomly from parents and/or from the environment. Additionally, the environmental pool of available microbes was constituted by fixed and persistent microbial OTUs and by contributions from host individuals in the preceding generation. In this paper, we extend our neutral models to allow selection to operate on both hosts and microbes. We do this by constructing a phenome for each microbial OTU consisting of a sample of traits that influence host and microbial fitnesses independently. Microbial traits can influence the fitness of hosts ("host selection") and the fitness of microbes ("trait-mediated microbial selection"). Additionally, the fitness effects of traits on microbes can be modified by their hosts ("host-mediated microbial selection"). We simulate the effects of these three types of selection, individually or in combination, on microbiome diversities and the fitnesses of hosts and microbes over several thousand generations of hosts. We show that microbiome diversity is strongly influenced by selection acting on microbes. Selection acting on hosts only influences microbiome diversity when there is near-complete direct or indirect parental contribution to the microbiomes of offspring. Unsurprisingly, microbial fitness increases under microbial selection. Interestingly, when host selection operates, host fitness only increases under two conditions: (1) when there is a strong parental contribution to microbial communities or (2) in the absence of a strong

  1. Considering bioactivity in modelling continental growth and the Earth's evolution

    Science.gov (United States)

    Höning, D.; Spohn, T.

    2013-09-01

    The complexity of planetary evolution increases with the number of interacting reservoirs. On Earth, even the biosphere is speculated to interact with the interior. It has been argued (e.g., Rosing et al. 2006; Sleep et al, 2012) that the formation of continents could be a consequence of bioactivity harvesting solar energy through photosynthesis to help build the continents and that the mantle should carry a chemical biosignature. Through plate tectonics, the surface biosphere can impact deep subduction zone processes and the interior of the Earth. Subducted sediments are particularly important, because they influence the Earth's interior in several ways, and in turn are strongly influenced by the Earth's biosphere. In our model, we use the assumption that a thick sedimentary layer of low permeability on top of the subducting oceanic crust, caused by a biologically enhanced weathering rate, can suppress shallow dewatering. This in turn leads to greater vailability of water in the source region of andesitic partial melt, resulting in an enhanced rate of continental production and regassing rate into the mantle. Our model includes (i) mantle convection, (ii) continental erosion and production, and (iii) mantle water degassing at mid-ocean ridges and regassing at subduction zones. The mantle viscosity of our model depends on (i) the mantle water concentration and (ii) the mantle temperature, whose time dependency is given by radioactive decay of isotopes in the Earth's mantle. Boundary layer theory yields the speed of convection and the water outgassing rate of the Earth's mantle. Our results indicate that present day values of continental surface area and water content of the Earth's mantle represent an attractor in a phase plane spanned by both parameters. We show that the biologic enhancement of the continental erosion rate is important for the system to reach this fixed point. An abiotic Earth tends to reach an alternative stable fixed point with a smaller

  2. TESTING MODELS OF MAGNETIC FIELD EVOLUTION OF NEUTRON STARS WITH THE STATISTICAL PROPERTIES OF THEIR SPIN EVOLUTIONS

    International Nuclear Information System (INIS)

    Zhang Shuangnan; Xie Yi

    2012-01-01

    We test models for the evolution of neutron star (NS) magnetic fields (B). Our model for the evolution of the NS spin is taken from an analysis of pulsar timing noise presented by Hobbs et al.. We first test the standard model of a pulsar's magnetosphere in which B does not change with time and magnetic dipole radiation is assumed to dominate the pulsar's spin-down. We find that this model fails to predict both the magnitudes and signs of the second derivatives of the spin frequencies (ν-double dot). We then construct a phenomenological model of the evolution of B, which contains a long-term decay (LTD) modulated by short-term oscillations; a pulsar's spin is thus modified by its B-evolution. We find that an exponential LTD is not favored by the observed statistical properties of ν-double dot for young pulsars and fails to explain the fact that ν-double dot is negative for roughly half of the old pulsars. A simple power-law LTD can explain all the observed statistical properties of ν-double dot. Finally, we discuss some physical implications of our results to models of the B-decay of NSs and suggest reliable determination of the true ages of many young NSs is needed, in order to constrain further the physical mechanisms of their B-decay. Our model can be further tested with the measured evolutions of ν-dot and ν-double dot for an individual pulsar; the decay index, oscillation amplitude, and period can also be determined this way for the pulsar.

  3. Preliminary conceptual model for mineral evolution in Yucca Mountain

    International Nuclear Information System (INIS)

    Duffy, C.J.

    1993-12-01

    A model is presented for mineral alteration in Yucca Mountain, Nevada, that suggests that the mineral transformations observed there are primarily controlled by the activity of aqueous silica. The rate of these reactions is related to the rate of evolution of the metastable silica polymorphs opal-CT and cristobalite assuming that a SiO 2(aq) is fixed at the equilibrium solubility of the most soluble silica polymorph present. The rate equations accurately predict the present depths of disappearance of opal-CT and cristobalite. The rate equations have also been used to predict the extent of future mineral alteration that may result from emplacement of a high-level nuclear waste repository in Yucca Mountain. Relatively small changes in mineralogy are predicted, but these predictions are based on the assumption that emplacement of a repository would not increase the pH of water in Yucca Mountain nor increase its carbonate content. Such changes may significantly increase mineral alteration. Some of the reactions currently occurring in Yucca Mountain consume H + and CO 3 2- . Combining reaction rate models for these reactions with water chemistry data may make it possible to estimate water flux through the basal vitrophyre of the Topopah Spring Member and to help confirm the direction and rate of flow of groundwater in Yucca Mountain

  4. Orchestrated structure evolution: modeling growth-regulated nanomanufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Abbasi, Shaghayegh; Boehringer, Karl F [Department of Electrical Engineering, University of Washington, Seattle, WA 98195-2500 (United States); Kitayaporn, Sathana; Schwartz, Daniel T, E-mail: karlb@washington.edu [Department of Chemical Engineering, University of Washington, Seattle, WA 98195-2500 (United States)

    2011-04-22

    Orchestrated structure evolution (OSE) is a scalable manufacturing method that combines the advantages of top-down (tool-directed) and bottom-up (self-propagating) approaches. The method consists of a seed patterning step that defines where material nucleates, followed by a growth step that merges seeded islands into the final patterned thin film. We develop a model to predict the completed pattern based on a computationally efficient approximate Green's function solution of the diffusion equation plus a Voronoi diagram based approach that defines the final grain boundary structure. Experimental results rely on electron beam lithography to pattern the seeds, followed by the mass transfer limited growth of copper via electrodeposition. The seed growth model is compared with experimental results to quantify nearest neighbor seed-to-seed interactions as well as how seeds interact with the pattern boundary to impact the local growth rate. Seed-to-seed and seed-to-pattern interactions are shown to result in overgrowth of seeds on edges and corners of the shape, where seeds have fewer neighbors. We explore how local changes to the seed location can be used to improve the patterning quality without increasing the manufacturing cost. OSE is shown to enable a unique set of trade-offs between the cost, time, and quality of thin film patterning.

  5. Molecular modeling of the microstructure evolution during carbon fiber processing

    Science.gov (United States)

    Desai, Saaketh; Li, Chunyu; Shen, Tongtong; Strachan, Alejandro

    2017-12-01

    The rational design of carbon fibers with desired properties requires quantitative relationships between the processing conditions, microstructure, and resulting properties. We developed a molecular model that combines kinetic Monte Carlo and molecular dynamics techniques to predict the microstructure evolution during the processes of carbonization and graphitization of polyacrylonitrile (PAN)-based carbon fibers. The model accurately predicts the cross-sectional microstructure of the fibers with the molecular structure of the stabilized PAN fibers and physics-based chemical reaction rates as the only inputs. The resulting structures exhibit key features observed in electron microcopy studies such as curved graphitic sheets and hairpin structures. In addition, computed X-ray diffraction patterns are in good agreement with experiments. We predict the transverse moduli of the resulting fibers between 1 GPa and 5 GPa, in good agreement with experimental results for high modulus fibers and slightly lower than those of high-strength fibers. The transverse modulus is governed by sliding between graphitic sheets, and the relatively low value for the predicted microstructures can be attributed to their perfect longitudinal texture. Finally, the simulations provide insight into the relationships between chemical kinetics and the final microstructure; we observe that high reaction rates result in porous structures with lower moduli.

  6. A simple model for research interest evolution patterns

    Science.gov (United States)

    Jia, Tao; Wang, Dashun; Szymanski, Boleslaw

    Sir Isaac Newton supposedly remarked that in his scientific career he was like ``...a boy playing on the sea-shore ...finding a smoother pebble or a prettier shell than ordinary''. His remarkable modesty and famous understatement motivate us to seek regularities in how scientists shift their research focus as the career develops. Indeed, despite intensive investigations on how microscopic factors, such as incentives and risks, would influence a scientist's choice of research agenda, little is known on the macroscopic patterns in the research interest change undertaken by individual scientists throughout their careers. Here we make use of over 14,000 authors' publication records in physics. By quantifying statistical characteristics in the interest evolution, we model scientific research as a random walk, which reproduces patterns in individuals' careers observed empirically. Despite myriad of factors that shape and influence individual choices of research subjects, we identified regularities in this dynamical process that are well captured by a simple statistical model. The results advance our understanding of scientists' behaviors during their careers and open up avenues for future studies in the science of science.

  7. Package models and the information crisis of prebiotic evolution.

    Science.gov (United States)

    Silvestre, Daniel A M M; Fontanari, José F

    2008-05-21

    The coexistence between different types of templates has been the choice solution to the information crisis of prebiotic evolution, triggered by the finding that a single RNA-like template cannot carry enough information to code for any useful replicase. In principle, confining d distinct templates of length L in a package or protocell, whose survival depends on the coexistence of the templates it holds in, could resolve this crisis provided that d is made sufficiently large. Here we review the prototypical package model of Niesert et al. [1981. Origin of life between Scylla and Charybdis. J. Mol. Evol. 17, 348-353] which guarantees the greatest possible region of viability of the protocell population, and show that this model, and hence the entire package approach, does not resolve the information crisis. In particular, we show that the total information stored in a viable protocell (Ld) tends to a constant value that depends only on the spontaneous error rate per nucleotide of the template replication mechanism. As a result, an increase of d must be followed by a decrease of L, so that the net information gain is null.

  8. The evolution of menstruation: A new model for genetic assimilation

    Science.gov (United States)

    Emera, D.; Romero, R.; Wagner, G.

    2012-01-01

    Why do humans menstruate while most mammals do not? Here, we present our answer to this long-debated question, arguing that (i) menstruation occurs as a mechanistic consequence of hormone-induced differentiation of the endometrium (referred to as spontaneous decidualization, or SD); (ii) SD evolved because of maternal-fetal conflict; and (iii) SD evolved by genetic assimilation of the decidualization reaction, which is induced by the fetus in non-menstruating species. The idea that menstruation occurs as a consequence of SD has been proposed in the past, but here we present a novel hypothesis on how SD evolved. We argue that decidualization became genetically stabilized in menstruating lineages, allowing females to prepare for pregnancy without any signal from the fetus. We present three models for the evolution of SD by genetic assimilation, based on recent advances in our understanding of the mechanisms of endometrial differentiation and implantation. Testing these models will ultimately shed light on the evolutionary significance of menstruation, as well as on the etiology of human reproductive disorders like endometriosis and recurrent pregnancy loss. PMID:22057551

  9. A numerical model for meltwater channel evolution in glaciers

    Directory of Open Access Journals (Sweden)

    A. H. Jarosch

    2012-04-01

    Full Text Available Meltwater channels form an integral part of the hydrological system of a glacier. Better understanding of how meltwater channels develop and evolve is required to fully comprehend supraglacial and englacial meltwater drainage. Incision of supraglacial stream channels and subsequent roof closure by ice deformation has been proposed in recent literature as a possible englacial conduit formation process. Field evidence for supraglacial stream incision has been found in Svalbard and Nepal. In Iceland, where volcanic activity provides meltwater with temperatures above 0 °C, rapid enlargement of supraglacial channels has been observed. Supraglacial channels provide meltwater through englacial passages to the subglacial hydrological systems of big ice sheets, which in turn affects ice sheet motion and their contribution to eustatic sea level change. By coupling, for the first time, a numerical ice dynamic model to a hydraulic model which includes heat transfer, we investigate the evolution of meltwater channels and their incision behaviour. We present results for different, constant meltwater fluxes, different channel slopes, different meltwater temperatures, different melt rate distributions in the channel as well as temporal variations in meltwater flux. The key parameters governing incision rate and depth are channel slope, meltwater temperature loss to the ice and meltwater flux. Channel width and geometry are controlled by melt rate distribution along the channel wall. Calculated Nusselt numbers suggest that turbulent mixing is the main heat transfer mechanism in the meltwater channels studied.

  10. A coupled geomorphic and ecological model of tidal marsh evolution.

    Science.gov (United States)

    Kirwan, Matthew L; Murray, A Brad

    2007-04-10

    The evolution of tidal marsh platforms and interwoven channel networks cannot be addressed without treating the two-way interactions that link biological and physical processes. We have developed a 3D model of tidal marsh accretion and channel network development that couples physical sediment transport processes with vegetation biomass productivity. Tidal flow tends to cause erosion, whereas vegetation biomass, a function of bed surface depth below high tide, influences the rate of sediment deposition and slope-driven transport processes such as creek bank slumping. With a steady, moderate rise in sea level, the model builds a marsh platform and channel network with accretion rates everywhere equal to the rate of sea-level rise, meaning water depths and biological productivity remain temporally constant. An increase in the rate of sea-level rise, or a reduction in sediment supply, causes marsh-surface depths, biomass productivity, and deposition rates to increase while simultaneously causing the channel network to expand. Vegetation on the marsh platform can promote a metastable equilibrium where the platform maintains elevation relative to a rapidly rising sea level, although disturbance to vegetation could cause irreversible loss of marsh habitat.

  11. Modeling of residual stress state in turning of 304L

    International Nuclear Information System (INIS)

    Valiorgue, F.; Rech, J.; Bergheau, J.M.

    2010-01-01

    Research presented in this paper aims to link machining parameters to residual stress state and helps understanding mechanisms responsible of machined surface properties modifications. The first presented works are based on an experimental campaign. They reproduce the finishing turning operation of 304L and allow observing the residual stress state evolution at the work piece surface and for an affected depth of 0.2 mm for such processes. Then, the finishing turning operation is simulated numerically in order to realize the same sensitivity study to cutting parameters. This simulation is based on an hybrid approach mixing experimental data and numerical simulation. This method allows getting round the classical difficulties of turning simulation by applying equivalent thermo mechanical loadings onto the work piece surface without modeling the material separation phenomena. Moreover the numerical model uses an hardening law taking into account dynamic recrystallization phenomena. (authors)

  12. Towards GLUE2 evolution of the computing element information model

    CERN Document Server

    Andreozzi, S; Field, L; Kónya, B

    2008-01-01

    A key advantage of Grid systems is the ability to share heterogeneous resources and services between traditional administrative and organizational domains. This ability enables virtual pools of resources to be created and assigned to groups of users. Resource awareness, the capability of users or user agents to have knowledge about the existence and state of resources, is required in order utilize the resource. This awareness requires a description of the services and resources typically defined via a community-agreed information model. One of the most popular information models, used by a number of Grid infrastructures, is the GLUE Schema, which provides a common language for describing Grid resources. Other approaches exist, however they follow different modeling strategies. The presence of different flavors of information models for Grid resources is a barrier for enabling inter-Grid interoperability. In order to solve this problem, the GLUE Working Group in the context of the Open Grid Forum was started. ...

  13. Argon-41 production and evolution at the Oregon State University TRIGA Reactor (OSTR)

    International Nuclear Information System (INIS)

    Anellis, L.G.; Johnson, A.G.; Higginbotham, J.F.

    1988-01-01

    In this study, argon-41 concentrations were measured at various locations within the reactor facility to assess the accuracy of models used to predict argon-41 evolution from the reactor tank, and to determine the relationship between argon gas evolution from the tank and subsequent argon-41 concentrations throughout the reactor room. In particular, argon-41 was measured directly above the reactor tank with the reactor tank lids closed, at other accessible locations on the reactor top with the tank lids both closed and open, and at several locations on the first floor of the reactor room. These measured concentrations were then compared to values calculated using a modified argon-41 production and evolution model for TRIGA reactor tanks and ventilation values applicable to the OSTR facility. The modified model was based in part on earlier TRIGA models for argon-41 production and release, but added features which improved the agreement between predicted and measured values. The approximate dose equivalent rate due to the presence of argon-41 in reactor room air was calculated for several different locations inside the OSTR facility. These dose rates were determined using the argon-41 concentration measured at each specific location, and were subsequently converted to a predicted quarterly dose equivalent for each location based on the reactor's operating history. The predicted quarterly dose equivalent values were then compared to quarterly doses measured by film badges deployed as dose-integrating area radiation monitors at the locations of interest. The results indicate that the modified production and evolution model is able to predict argon-41 concentrations to within a factor of ten when compared to the measured data. Quarterly dose equivalents calculated from the measured argon-41 concentrations and the reactor's operating history seemed consistent with results obtained from the integrating area radiation monitors. Given the argon-41 concentrations measured

  14. Quasiperiodicity in time evolution of the Bloch vector under the thermal Jaynes-Cummings model

    Science.gov (United States)

    Azuma, Hiroo; Ban, Masashi

    2014-07-01

    We study a quasiperiodic structure in the time evolution of the Bloch vector, whose dynamics is governed by the thermal Jaynes-Cummings model (JCM). Putting the two-level atom into a certain pure state and the cavity field into a mixed state in thermal equilibrium at initial time, we let the whole system evolve according to the JCM Hamiltonian. During this time evolution, motion of the Bloch vector seems to be in disorder. Because of the thermal photon distribution, both a norm and a direction of the Bloch vector change hard at random. In this paper, taking a different viewpoint compared with ones that we have been used to, we investigate quasiperiodicity of the Bloch vector’s trajectories. Introducing the concept of the quasiperiodic motion, we can explain the confused behaviour of the system as an intermediate state between periodic and chaotic motions. More specifically, we discuss the following two facts: (1) If we adjust the time interval Δt properly, figures consisting of plotted dots at the constant time interval acquire scale invariance under replacement of Δt by sΔt, where s(>1) is an arbitrary real but not transcendental number. (2) We can compute values of the time variable t, which let |Sz(t)| (the absolute value of the z-component of the Bloch vector) be very small, with the Diophantine approximation (a rational approximation of an irrational number).

  15. The Group That Calls Itself a State: Understanding the Evolution and Challenges of the Islamic State

    Science.gov (United States)

    2014-12-01

    to mount a fight against the global establishment in the form of states, al-Zarqawi was envisaging an establishment of his own. The embryo of al...the IS far too much credit in shaping its own destiny . Were it not for many unplanned and unintended events (see the section of this report on the

  16. A Monte Carlo model for 3D grain evolution during welding

    Science.gov (United States)

    Rodgers, Theron M.; Mitchell, John A.; Tikare, Veena

    2017-09-01

    Welding is one of the most wide-spread processes used in metal joining. However, there are currently no open-source software implementations for the simulation of microstructural evolution during a weld pass. Here we describe a Potts Monte Carlo based model implemented in the SPPARKS kinetic Monte Carlo computational framework. The model simulates melting, solidification and solid-state microstructural evolution of material in the fusion and heat-affected zones of a weld. The model does not simulate thermal behavior, but rather utilizes user input parameters to specify weld pool and heat-affect zone properties. Weld pool shapes are specified by Bézier curves, which allow for the specification of a wide range of pool shapes. Pool shapes can range from narrow and deep to wide and shallow representing different fluid flow conditions within the pool. Surrounding temperature gradients are calculated with the aide of a closest point projection algorithm. The model also allows simulation of pulsed power welding through time-dependent variation of the weld pool size. Example simulation results and comparisons with laboratory weld observations demonstrate microstructural variation with weld speed, pool shape, and pulsed-power.

  17. Identifying and Modeling Dynamic Preference Evolution in Multipurpose Water Resources Systems

    Science.gov (United States)

    Mason, E.; Giuliani, M.; Castelletti, A.; Amigoni, F.

    2018-04-01

    Multipurpose water systems are usually operated on a tradeoff of conflicting operating objectives. Under steady state climatic and socioeconomic conditions, such tradeoff is supposed to represent a fair and/or efficient preference. Extreme variability in external forcing might affect water operators' risk aversion and force a change in her/his preference. Properly accounting for these shifts is key to any rigorous retrospective assessment of the operator's behaviors, and to build descriptive models for projecting the future system evolution. In this study, we explore how the selection of different preferences is linked to variations in the external forcing. We argue that preference selection evolves according to recent, extreme variations in system performance: underperforming in one of the objectives pushes the preference toward the harmed objective. To test this assumption, we developed a rational procedure to simulate the operator's preference selection. We map this selection onto a multilateral negotiation, where multiple virtual agents independently optimize different objectives. The agents periodically negotiate a compromise policy for the operation of the system. Agents' attitudes in each negotiation step are determined by the recent system performance measured by the specific objective they maximize. We then propose a numerical model of preference dynamics that implements a concept from cognitive psychology, the availability bias. We test our modeling framework on a synthetic lake operated for flood control and water supply. Results show that our model successfully captures the operator's preference selection and dynamic evolution driven by extreme wet and dry situations.

  18. Female mating preferences determine system-level evolution in a gene network model.

    Science.gov (United States)

    Fierst, Janna L

    2013-06-01

    Environmental patterns of directional, stabilizing and fluctuating selection can influence the evolution of system-level properties like evolvability and mutational robustness. Intersexual selection produces strong phenotypic selection and these dynamics may also affect the response to mutation and the potential for future adaptation. In order to to assess the influence of mating preferences on these evolutionary properties, I modeled a male trait and female preference determined by separate gene regulatory networks. I studied three sexual selection scenarios: sexual conflict, a Gaussian model of the Fisher process described in Lande (in Proc Natl Acad Sci 78(6):3721-3725, 1981) and a good genes model in which the male trait signalled his mutational condition. I measured the effects these mating preferences had on the potential for traits and preferences to evolve towards new states, and mutational robustness of both the phenotype and the individual's overall viability. All types of sexual selection increased male phenotypic robustness relative to a randomly mating population. The Fisher model also reduced male evolvability and mutational robustness for viability. Under good genes sexual selection, males evolved an increased mutational robustness for viability. Females choosing their mates is a scenario that is sufficient to create selective forces that impact genetic evolution and shape the evolutionary response to mutation and environmental selection. These dynamics will inevitably develop in any population where sexual selection is operating, and affect the potential for future adaptation.

  19. Towards GLUE 2: evolution of the computing element information model

    International Nuclear Information System (INIS)

    Andreozzi, S; Burke, S; Field, L; Konya, B

    2008-01-01

    A key advantage of Grid systems is the ability to share heterogeneous resources and services between traditional administrative and organizational domains. This ability enables virtual pools of resources to be created and assigned to groups of users. Resource awareness, the capability of users or user agents to have knowledge about the existence and state of resources, is required in order utilize the resource. This awareness requires a description of the services and resources typically defined via a community-agreed information model. One of the most popular information models, used by a number of Grid infrastructures, is the GLUE Schema, which provides a common language for describing Grid resources. Other approaches exist, however they follow different modeling strategies. The presence of different flavors of information models for Grid resources is a barrier for enabling inter-Grid interoperability. In order to solve this problem, the GLUE Working Group in the context of the Open Grid Forum was started. The purpose of the group is to oversee a major redesign of the GLUE Schema which should consider the successful modeling choices and flaws that have emerged from practical experience and modeling choices from other initiatives. In this paper, we present the status of the new model for describing computing resources as the first output from the working group with the aim of dissemination and soliciting feedback from the community

  20. Ecoregions of the conterminous United States: evolution of a hierarchical spatial framework

    Science.gov (United States)

    Omernik, James M.; Griffith, Glenn E.

    2014-01-01

    A map of ecological regions of the conterminous United States, first published in 1987, has been greatly refined and expanded into a hierarchical spatial framework in response to user needs, particularly by state resource management agencies. In collaboration with scientists and resource managers from numerous agencies and institutions in the United States, Mexico, and Canada, the framework has been expanded to cover North America, and the original ecoregions (now termed Level III) have been refined, subdivided, and aggregated to identify coarser as well as more detailed spatial units. The most generalized units (Level I) define 10 ecoregions in the conterminous U.S., while the finest-scale units (Level IV) identify 967 ecoregions. In this paper, we explain the logic underpinning the approach, discuss the evolution of the regional mapping process, and provide examples of how the ecoregions were distinguished at each hierarchical level. The variety of applications of the ecoregion framework illustrates its utility in resource assessment and management.

  1. Evolution of the cosmological horizons in a universe with countably infinitely many state equations

    Energy Technology Data Exchange (ETDEWEB)

    Margalef-Bentabol, Berta; Cepa, Jordi [Departamento de Astrofísica, Universidad de la Laguna, E-38205 La Laguna, Tenerife (Spain); Margalef-Bentabol, Juan, E-mail: bmb@cca.iac.es, E-mail: juanmargalef@estumail.ucm.es, E-mail: jcn@iac.es [Facultad de Ciencias Matemáticas, Universidad Complutense de Madrid, E-28040 Madrid (Spain)

    2013-02-01

    This paper is the second of two papers devoted to the study of the evolution of the cosmological horizons (particle and event horizons). Specifically, in this paper we consider a general accelerated universe with countably infinitely many constant state equations, and we obtain simple expressions in terms of their respective recession velocities that generalize the previous results for one and two state equations. We also provide a qualitative study of the values of the horizons and their velocities at the origin of the universe and at the far future, and we prove that these values only depend on one dominant state equation. Finally, we compare both horizons and determine when one is larger than the other.

  2. A 1-D mechanistic model for the evolution of earthflow-prone hillslopes

    Science.gov (United States)

    Booth, Adam M.; Roering, Josh J.

    2011-12-01

    In mountainous terrain, deep-seated landslides transport large volumes of material on hillslopes, exerting a dominant control on erosion rates and landscape form. Here, we develop a mathematical landscape evolution model to explore interactions between deep-seated earthflows, soil creep, and gully processes at the drainage basin scale over geomorphically relevant (>103 year) timescales. In the model, sediment flux or incision laws for these three geomorphic processes combine to determine the morphology of actively uplifting and eroding steady state topographic profiles. We apply the model to three sites, one in the Gabilan Mesa, California, with no earthflow activity, and two along the Eel River, California, with different lithologies and varying levels of historic earthflow activity. Representative topographic profiles from these sites are consistent with model predictions in which the magnitude of a dimensionless earthflow number, based on a non-Newtonian flow rheology, reflects the magnitude of recent earthflow activity on the different hillslopes. The model accurately predicts the behavior of earthflow collection and transport zones observed in the field and estimates long-term average sediment fluxes that are due to earthflows, in agreement with historical rates at our field sites. Finally, our model predicts that steady state hillslope relief in earthflow-prone terrain increases nonlinearly with the tectonic uplift rate, suggesting that the mean hillslope angle may record uplift rate in earthflow-prone landscapes even at high uplift rates, where threshold slope processes normally limit further topographic development.

  3. A Process Model of Partnership Evolution Around New IT Initiatives

    Science.gov (United States)

    Kestilä, Timo; Salmivalli, Lauri; Salmela, Hannu; Vahtera, Annukka

    Prior research on inter-organizational information systems has focused primarily on dyadic network relationships, where agreements about information exchange are made between two organizations. The focus of this research is on the processes through which IT decisions are made within larger inter-organizational networks with several network parties. The research draws from network theories in organization science to identify three alternative mechanisms for making network level commitments: contracts, rules and values. In addition, theoretical concepts are searched from dynamic network models, which identify different cycles and stages in network evolution. The empirical research was conducted in two networks. The first one comprises of four municipalities which began collaboration in the deployment of IT in early childhood education (ECE). The second network involves a case where several organizations, both private and public, initiated a joint effort to implement a national level electronic prescription system (EPS). The frameworks and concepts drawn from organizational theories are used to explain success of the first case and the failure of the latter case. The paper contributes to prior IOS research by providing a new theory-based framework for the analysis of early stages of building organizational networks around innovative IT initiatives.

  4. Enrichment of Zinc in Galactic Chemodynamical Evolution Models

    Science.gov (United States)

    Hirai, Yutaka; Saitoh, Takayuki R.; Ishimaru, Yuhri; Wanajo, Shinya

    2018-03-01

    The heaviest iron-peak element Zinc (Zn) has been used as an important tracer of cosmic chemical evolution. Spectroscopic observations of the metal-poor stars in Local Group galaxies show an increasing trend of [Zn/Fe] ratios toward lower metallicity. However, the enrichment of Zn in galaxies is not well understood due to poor knowledge of astrophysical sites of Zn, as well as metal mixing in galaxies. Here we show possible explanations for the observed trend by taking into account electron-capture supernovae (ECSNe) as one of the sources of Zn in our chemodynamical simulations of dwarf galaxies. We find that the ejecta from ECSNe contribute to stars with [Zn/Fe] ≳ 0.5. We also find that scatters of [Zn/Fe] in higher metallicities originate from the ejecta of type Ia supernovae. On the other hand, it appears difficult to explain the observed trends if we do not consider ECSNe as a source of Zn. These results come from an inhomogeneous spatial metallicity distribution due to the inefficiency of the metal mixing. We find that the optimal value of the scaling factor for the metal diffusion coefficient is ∼0.01 in the shear-based metal mixing model in smoothed particle hydrodynamics simulations. These results suggest that ECSNe could be one of the contributors of the enrichment of Zn in galaxies.

  5. THE QUASI-ROCHE LOBE OVERFLOW STATE IN THE EVOLUTION OF CLOSE BINARY SYSTEMS CONTAINING A RADIO PULSAR

    Energy Technology Data Exchange (ETDEWEB)

    Benvenuto, O. G.; De Vito, M. A. [Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata and Instituto de Astrofísica de La Plata (IALP), CCT-CONICET-UNLP. Paseo del Bosque S/N (B1900FWA), La Plata (Argentina); Horvath, J. E., E-mail: adevito@fcaglp.unlp.edu.ar, E-mail: foton@iag.usp.br [Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo R. do Matão 1226 (05508-090), Cidade Universitária, São Paulo SP (Brazil)

    2015-01-01

    We study the evolution of close binary systems formed by a normal (solar composition), intermediate-mass-donor star together with a neutron star. We consider models including irradiation feedback and evaporation. These nonstandard ingredients deeply modify the mass-transfer stages of these binaries. While models that neglect irradiation feedback undergo continuous, long-standing mass-transfer episodes, models including these effects suffer a number of cycles of mass transfer and detachment. During mass transfer, the systems should reveal themselves as low-mass X-ray binaries (LMXBs), whereas when they are detached they behave as binary radio pulsars. We show that at these stages irradiated models are in a Roche lobe overflow (RLOF) state or in a quasi-RLOF state. Quasi-RLOF stars have radii slightly smaller than their Roche lobes. Remarkably, these conditions are attained for an orbital period as well as donor mass values in the range corresponding to a family of binary radio pulsars known as ''redbacks''. Thus, redback companions should be quasi-RLOF stars. We show that the characteristics of the redback system PSR J1723-2837 are accounted for by these models. In each mass-transfer cycle these systems should switch from LMXB to binary radio pulsar states with a timescale of approximately one million years. However, there is recent and fast growing evidence of systems switching on far shorter, human timescales. This should be related to instabilities in the accretion disk surrounding the neutron star and/or radio ejection, still to be included in the model having the quasi-RLOF state as a general condition.

  6. Nutrient-dependent/pheromone-controlled adaptive evolution: a model

    Directory of Open Access Journals (Sweden)

    James Vaughn Kohl

    2013-06-01

    Full Text Available Background: The prenatal migration of gonadotropin-releasing hormone (GnRH neurosecretory neurons allows nutrients and human pheromones to alter GnRH pulsatility, which modulates the concurrent maturation of the neuroendocrine, reproductive, and central nervous systems, thus influencing the development of ingestive behavior, reproductive sexual behavior, and other behaviors. Methods: This model details how chemical ecology drives adaptive evolution via: (1 ecological niche construction, (2 social niche construction, (3 neurogenic niche construction, and (4 socio-cognitive niche construction. This model exemplifies the epigenetic effects of olfactory/pheromonal conditioning, which alters genetically predisposed, nutrient-dependent, hormone-driven mammalian behavior and choices for pheromones that control reproduction via their effects on luteinizing hormone (LH and systems biology. Results: Nutrients are metabolized to pheromones that condition behavior in the same way that food odors condition behavior associated with food preferences. The epigenetic effects of olfactory/pheromonal input calibrate and standardize molecular mechanisms for genetically predisposed receptor-mediated changes in intracellular signaling and stochastic gene expression in GnRH neurosecretory neurons of brain tissue. For example, glucose and pheromones alter the hypothalamic secretion of GnRH and LH. A form of GnRH associated with sexual orientation in yeasts links control of the feedback loops and developmental processes required for nutrient acquisition, movement, reproduction, and the diversification of species from microbes to man. Conclusion: An environmental drive evolved from that of nutrient ingestion in unicellular organisms to that of pheromone-controlled socialization in insects. In mammals, food odors and pheromones cause changes in hormones such as LH, which has developmental affects on pheromone-controlled sexual behavior in nutrient-dependent reproductively

  7. Numerical modelling of the atmospheric mixing-layer diurnal evolution

    International Nuclear Information System (INIS)

    Molnary, L. de.

    1990-03-01

    This paper introduce a numeric procedure to determine the temporal evolution of the height, potential temperature and mixing ratio in the atmospheric mixing layer. The time and spatial derivatives were evaluated via forward in time scheme to predict the local evolution of the mixing-layer parameters, and a forward in time, upstream in space scheme to predict the evolution of the mixing-layer over a flat region with a one-dimensional advection component. The surface turbulent fluxes of sensible and latent heat were expressed using a simple sine wave that is function of the hour day and kind of the surface (water or country). (author) [pt

  8. Modeling of the flow behavior of SAE 8620H combing microstructure evolution in hot forming

    Science.gov (United States)

    Fu, Xiaobin; Wang, Baoyu; Tang, Xuefeng

    2017-10-01

    With the development of net-shape forming technology, hot forming process is widely applied to manufacturing gear parts, during which, materials suffer severe plastic distortion and microstructure changes continually. In this paper, to understand and model the flow behavior and microstructure evolution, SAE 8620H, a widely used gear steel, is selected as the object and the flow behavior and microstructure evolution are observed by an isothermal hot compression tests at 1273-1373 K with a strain rate of 0.1-10 s-1. Depending on the results of the compression test, a set of internal-state-variable based unified constitutive equations is put forward to describe the flow behavior and microstructure evaluation of SAE 8620H. Moreover, the evaluation of the dislocation density and the fraction of dynamic recrystallization based on the theory of thermal activation is modeled and reincorporated into the constitutive law. The material parameters in the constitutive model are calculated based on the measured flow stress and dynamic recrystallization fraction. The predicted flow stress under different deformation conditions has a good agreement with the measured results.

  9. Modeling in the Common Core State Standards

    Science.gov (United States)

    Tam, Kai Chung

    2011-01-01

    The inclusion of modeling and applications into the mathematics curriculum has proven to be a challenging task over the last fifty years. The Common Core State Standards (CCSS) has made mathematical modeling both one of its Standards for Mathematical Practice and one of its Conceptual Categories. This article discusses the need for mathematical…

  10. Communicative Modelling of Cultural Transmission and Evolution Through a Holographic Cognition Model

    Directory of Open Access Journals (Sweden)

    Ambjörn Naeve

    2012-12-01

    Full Text Available This article presents communicative ways to model the transmission and evolution of the processes and artefacts of a culture as the result of ongoing interactions between its members - both at the tacit and the explicit level. The purpose is not to model the entire cultural process, but to provide semantically rich “conceptual placeholders” for modelling any cultural activity that is considered important enough within a certain context. The general purpose of communicative modelling is to create models that improve the quality of communication between people. In order to capture the subjective aspects of Gregory Bateson’s definition of information as “a difference that makes a difference,” the article introduces a Holographic Cognition Model that uses optical holography as an analogy for human cognition, with the object beam of holography corresponding to the first difference (the situation that the cognitive agent encounters, and the reference beam of holography corresponding to the subjective experiences and biases that the agent brings to the situation, and which makes the second difference (the interference/interpretation pattern unique for each agent. By combining the HCM with a semantically rich and recursive form of process modelling, based on the SECI-theory of knowledge creation, we arrive at way to model the cultural transmission and evolution process that is consistent with the Unified Theory of Information (the Triple-C model with its emphasis on intra-, inter- and supra-actions.

  11. Antigenic and genetic evolution of contemporary swine H1 influenza viruses in the United States.

    Science.gov (United States)

    Rajao, Daniela S; Anderson, Tavis K; Kitikoon, Pravina; Stratton, Jered; Lewis, Nicola S; Vincent, Amy L

    2018-05-01

    Several lineages of influenza A viruses (IAV) currently circulate in North American pigs. Genetic diversity is further increased by transmission of IAV between swine and humans and subsequent evolution. Here, we characterized the genetic and antigenic evolution of contemporary swine H1N1 and H1N2 viruses representing clusters H1-α (1A.1), H1-β (1A.2), H1pdm (1A.3.3.2), H1-γ (1A.3.3.3), H1-δ1 (1B.2.2), and H1-δ2 (1B.2.1) currently circulating in pigs in the United States. The δ1-viruses diversified into two new genetic clades, H1-δ1a (1B.2.2.1) and H1-δ1b (1B.2.2.2), which were also antigenically distinct from the earlier H1-δ1-viruses. Further characterization revealed that a few key amino acid changes were associated with antigenic divergence in these groups. The continued genetic and antigenic evolution of contemporary H1 viruses might lead to loss of vaccine cross-protection that could lead to significant economic impact to the swine industry, and represents a challenge to public health initiatives that attempt to minimize swine-to-human IAV transmission. Published by Elsevier Inc.

  12. A Thermal Evolution Model of the Earth Including the Biosphere, Continental Growth and Mantle Hydration

    Science.gov (United States)

    Höning, D.; Spohn, T.

    2014-12-01

    By harvesting solar energy and converting it to chemical energy, photosynthetic life plays an important role in the energy budget of Earth [2]. This leads to alterations of chemical reservoirs eventually affecting the Earth's interior [4]. It further has been speculated [3] that the formation of continents may be a consequence of the evolution life. A steady state model [1] suggests that the Earth without its biosphere would evolve to a steady state with a smaller continent coverage and a dryer mantle than is observed today. We present a model including (i) parameterized thermal evolution, (ii) continental growth and destruction, and (iii) mantle water regassing and outgassing. The biosphere enhances the production rate of sediments which eventually are subducted. These sediments are assumed to (i) carry water to depth bound in stable mineral phases and (ii) have the potential to suppress shallow dewatering of the underlying sediments and crust due to their low permeability. We run a Monte Carlo simulation for various initial conditions and treat all those parameter combinations as success which result in the fraction of continental crust coverage observed for present day Earth. Finally, we simulate the evolution of an abiotic Earth using the same set of parameters but a reduced rate of continental weathering and erosion. Our results suggest that the origin and evolution of life could have stabilized the large continental surface area of the Earth and its wet mantle, leading to the relatively low mantle viscosity we observe at present. Without photosynthetic life on our planet, the Earth would be geodynamical less active due to a dryer mantle, and would have a smaller fraction of continental coverage than observed today. References[1] Höning, D., Hansen-Goos, H., Airo, A., Spohn, T., 2014. Biotic vs. abiotic Earth: A model for mantle hydration and continental coverage. Planetary and Space Science 98, 5-13. [2] Kleidon, A., 2010. Life, hierarchy, and the

  13. Science standards: The foundation of evolution education in the United States

    Directory of Open Access Journals (Sweden)

    Elizabeth Watts

    2016-12-01

    Full Text Available Science standards and textbooks have a huge impact on the manner in which evolution is taught in American classrooms. Standards dictate how much time and what points have to be dedicated to the subject in order to prepare students for state-wide assessments, while the textbooks will largely determine how the subject is presented in the classroom. In the United States both standards and textbooks are determined at the state-level through a political process. Currently there is a tremendous amount of pressure arising from anti-evolutionists in the United States to weaken or omit the teaching of evolution despite recommendations from central institutions such as the National Academy of Science. Results from the Program for International Student Assessment (PISA showed that not only are American students performing below average, but also that their performance is declining as they scored worse in 2012 than they did in 2010. Interestingly PISA also found that the internal variation within a country is often greater than between countries with a variation of up to 300 points, which is equivalent to seven years of education pointing to the extreme heterogeneous quality of education within a country (OECD, 2012. An implementation of strong standards would not only help to increase the average performance of American students but could also alleviate the vast discrepancy between the highest and lowest scoring groups of American students. Although the Next Generation Science Standards have been in existence since 2013 and A Framework for K-12 Science Education has been available to the public since 2011 many American states still continue to create their own standards that, according to the Fordham study, are well below par (Lerner et al., 2012. Due to the political nature of the adoption procedure of standards and textbooks, there are many opportunities for interested individuals to get involved in the process of improving these fundamental elements of

  14. Simulating the evolution of industries using a dynamic behavioural model

    OpenAIRE

    Kunc, Martin

    2004-01-01

    Investment decisions determine that not only the evolution of industries is hard to forecast with certainty but also industries may have different dynamic behaviour and evolutionary paths. In this paper we present a behavioural framework to simulate the evolution of industries. Two factors determine the dynamic behaviour of an industry: managerial decision-making and the interconnected set of resources. Managerial decision-making significantly affects the dynamic behaviour of firms. Bounded r...

  15. Model to the evolution of the organic matter in the pampa's soil. Relation with cultivation systems

    International Nuclear Information System (INIS)

    Andriulo, Adrian; Mary, Bruno; Guerif, Jerome; Balesdent, Jerome

    1996-08-01

    The objective of the work is to present a model to describe the evolution of the organic matter in soils of the Argentine's pampa. This model can be utilised to evaluate the evolution of the soil's fertility in the agricultural production at this moment. Three kinds of assay were done. The determination of organic carbon made possible to prove the Henin-Dupuis model and a derived model

  16. A mechanistic model for the evolution of multicellularity

    Science.gov (United States)

    Amado, André; Batista, Carlos; Campos, Paulo R. A.

    2018-02-01

    Through a mechanistic approach we investigate the formation of aggregates of variable sizes, accounting mechanisms of aggregation, dissociation, death and reproduction. In our model, cells can produce two metabolites, but the simultaneous production of both metabolites is costly in terms of fitness. Thus, the formation of larger groups can favor the aggregates to evolve to a configuration where division of labor arises. It is assumed that the states of the cells in a group are those that maximize organismal fitness. In the model it is considered that the groups can grow linearly, forming a chain, or compactly keeping a roughly spherical shape. Starting from a population consisting of single-celled organisms, we observe the formation of groups with variable sizes and usually much larger than two-cell aggregates. Natural selection can favor the formation of large groups, which allows the system to achieve new and larger fitness maxima.

  17. Modeling and Measurement of Stress and Strain Evolution in Cu Interconnects

    International Nuclear Information System (INIS)

    Besser, Paul R.; Zhai, Charlie Jun

    2004-01-01

    The damascene fabrication method and the introduction of low-K dielectrics present a host of reliability challenges to Cu interconnects and fundamentally change the mechanical stress state of Cu lines used as interconnects for integrated circuits. In order to capture the effect of individual process steps on the stress evolution in the BEoL (Back End of Line), a process-oriented finite element modeling (FEM) approach was developed. In this model, the complete stress history at any step of BEoL can be simulated as a dual damascene Cu structure is fabricated. The model was calibrated with both wafer-curvature blanket film measurements and X-Ray diffraction (XRD) measurement of metal line stress. The Cu line stress evolution was simulated during the process of multi-step processing for dual damascene Cu/TEOS and Cu/low-k structures. The in-plane stress of Cu lines is nearly independent of subsequent processes, while the out-of-plane stress increases considerably with the subsequent process steps. The modeling results will be compared with recent XRD measurements and extended generically to illustrate the relative influence of the dielectric (ILD) modulus (E) and coefficient of thermal expansion (CTE) on strain/stress in the Cu lines. It will be shown that the stress magnitude and state (hydrostatic, deviatoric) depend on ILD properties. The stress along the line length (longitudinal) is substrate-dominated, while the transverse and normal stresses vary with both CTE and modulus of the dielectric. The hydrostatic stress is primarily determined by ILD modulus and is nearly independent of the ILD CTE, while the Von Mises stress depends on both CTE and E of the ILD. The stress of the Cu line tends to be more deviatoric with spin-on low K ILDs, and more hydrostatic with oxide encapsulation

  18. A philosophy of rivers: Equilibrium states, channel evolution, teleomatic change and least action principle

    Science.gov (United States)

    Nanson, Gerald C.; Huang, He Qing

    2018-02-01

    Until recently no universal agreement as to a philosophical or scientific methodological framework has been proposed to guide the study of fluvial geomorphology. An understanding of river form and process requires an understanding of the principles that govern the behaviour and evolution of alluvial rivers at the most fundamental level. To date, the investigations of such principles have followed four approaches: develop qualitative unifying theories that are usually untested; collect and examine data visually and statistically to define semi-quantitative relationships among variables; apply Newtonian theoretical and empirical mechanics in a reductionist manner; resolve the primary flow equations theoretically by assuming maximum or minimum outputs. Here we recommend not a fifth but an overarching philosophy to embrace all four: clarifying and formalising an understanding of the evolution of river channels and iterative directional changes in the context of least action principle (LAP), the theoretical basis of variational mechanics. LAP is exemplified in rivers in the form of maximum flow efficiency (MFE). A sophisticated understanding of evolution in its broadest sense is essential to understand how rivers adjust towards an optimum state rather than towards some other. Because rivers, as dynamic contemporary systems, flow in valleys that are commonly historical landforms and often tectonically determined, we propose that most of the world's alluvial rivers are over-powered for the work they must do. To remain stable they commonly evolve to expend surplus energy via a variety of dynamic equilibrium forms that will further adjust, where possible, to maximise their stability as much less common MFE forms in stationary equilibrium. This paper: 1. Shows that the theory of evolution is derived from, and applicable to, both the physical and biological sciences; 2. Focusses the development of theory in geomorphology on the development of equilibrium theory; 3. Proposes

  19. Developing Model Benchtop Systems for Microbial Experimental Evolution

    Science.gov (United States)

    Gentry, D.; Wang, J.; Arismendi, D.; Alvarez, J.; Ouandji, C.; Blaich, J.

    2017-12-01

    Understanding how microbes impact an ecosystem has improved through advances of molecular and genetic tools, but creating complex systems that emulate natural biology goes beyond current technology. In fact, many chemical, biological, and metabolic pathways of even model organisms are still poorly characterized. Even then, standard laboratory techniques for testing microbial impact on environmental change can have many drawbacks; they are time-consuming, labor intensive, and are at risk of contamination. By having an automated process, many of these problems can be reduced or even eliminated. We are developing a benchtop system that can run for long periods of time without the need for human intervention, involve multiple environmental stressors at once, perform real-time adjustments of stressor exposure based on current state of the population, and minimize contamination risks. Our prototype device allows operators to generate an analogue of real world micro-scale ecosystems that can be used to model the effects of disruptive environmental change on microbial ecosystems. It comprises of electronics, mechatronics, and fluidics based systems to control, measure, and evaluate the before and after state of microbial cultures from exposure to environmental stressors. Currently, it uses four parallel growth chambers to perform tests on liquid cultures. To measure the population state, optical sensors (LED/photodiode) are used. Its primary selection pressure is UV-C radiation, a well-studied stressor known for its cell- and DNA- damaging effects and as a mutagen. Future work will involve improving the current growth chambers, as well as implementing additional sensors and environmental stressors into the system. Full integration of multiple culture testing will allow inter-culture comparisons. Besides the temperature and OD sensors, other types of sensors can be integrated such as conductivity, biomass, pH, and dissolved gasses such as CO2 and O2. Additional

  20. Middle proterozoic supra crustal and brazilian orogeny in the southeast Ceara state: a mono cyclic evolution

    International Nuclear Information System (INIS)

    Sa, J.M.; Bezerra, F.H.R.; Freitas Macedo, M.H. de; Pereira, R.

    1988-01-01

    The Oros belt is situated in the southeastern part of Ceara state, Brazil, and geologically pertains to the Borborema province. This belt comprises a volcano-sedimentary sequence of middle proterozoic age resting unconformably upon basement of Archean/low proterozoic age. In the geological map of Ceara state, this belt displays an elongate shape towards N-S, turning to ENE-WSW in the south, and reaches 12 km wide in the central park. This paper describes the relationships between the country rocks and the supra crustal sequence, as well as the plutonic intrusions and their tectonic metamorphic evolution. New Rb-Sr whole-rock dates are presented which are very important to separate anorogenic and syn-orogenic granites. (author)

  1. Time Evolution of the Excimer State of a Conjugated Polymer Laser

    Directory of Open Access Journals (Sweden)

    Wafa Musa Mujamammi

    2017-11-01

    Full Text Available An excited dimer is an important complex formed in nano- or pico-second time scales in many photophysics and photochemistry applications. The spectral and temporal profile of the excimer state of a laser from a new conjugated polymer, namely, poly (9,9-dioctylfluorenyl-2,7-diyl (PFO, under several concentrations in benzene were investigated. These solutions were optically pumped by intense pulsed third-harmonic Nd:YAG laser (355-nm to obtain the amplified spontaneous emission (ASE spectra of a monomer and an excimer with bandwidths of 6 and 7 nm, respectively. The monomer and excimer ASEs were dependent on the PFO concentration, pump power, and temperature. Employing a sophisticated picosecond spectrometer, the time evolution of the excimer state of this polymer, which is over 400 ps, can be monitored.

  2. State-Space Modelling in Marine Science

    DEFF Research Database (Denmark)

    Albertsen, Christoffer Moesgaard

    State-space models provide a natural framework for analysing time series that cannot be observed without error. This is the case for fisheries stock assessments and movement data from marine animals. In fisheries stock assessments, the aim is to estimate the stock size; however, the only data...... available is the number of fish removed from the population and samples on a small fraction of the population. In marine animal movement, accurate position systems such as GPS cannot be used. Instead, inaccurate alternative must be used yielding observations with large errors. Both assessment and individual...... animal movement models are important for management and conservation of marine animals. Consequently, models should be developed to be operational in a management context while adequately evaluating uncertainties in the models. This thesis develops state-space models using the Laplace approximation...

  3. New Configuration of the Brazilian State: Liberty and Development in the Evolution of Government in Brazil

    Directory of Open Access Journals (Sweden)

    Maya Reyes-Ricon

    2010-10-01

    Full Text Available The recent events in the global economy have revitalized the debate about the size and functions of the State. The neoliberal discourse was put in check, reopening the discussions concerning Market Liberty and the importance of the State. Since the proclamation of the Republic, the Brazilian government has undergone numerous reforms, sometimes assuming a liberal, external market dependent orientation, while at other times assuming an authoritarian, developmental state-driven orientation. The aim of this article is to develop insights into the evolution of the governmental organization and reflect on the assumptions that lie behind the various reforms that have taken place since the beginning of the Republic. The theoretical framework is divided into three parts: Development and Liberty based on the perspectives of Friedrich Hayek and Amartya Sen; the role of the State and its impact on the economy and; the formats assumed by the Brazilian State throughout the history of the Republic. The latter part of the work returns to the theoretical framework, summarizing all that has been discussed in order to fulfil the aims of the study.

  4. Detailed analysis of evolution of the state of polarization in all-fiber polarization transformers.

    Science.gov (United States)

    Zhu, Xiushan; Jain, Ravinder K

    2006-10-30

    We present a detailed analysis of key attributes and performance characteristics of controllably-spun birefringent-fiber-based all-fiber waveplates or "all fiber polarization transformers" (AFPTs), first proposed and demonstrated by Huang [11]; these AFPTs consist essentially of a long carefully-designed "spin-twisted" high-birefringence fiber, fabricated by slowly varying the spin rate of a birefringent fiber preform (either from very fast to very slow or vice versa) while the fiber is being drawn. The evolution of the eigenstate from a linear polarization state to a circular polarization state, induced by slow variation of the intrinsic structure from linear anisotropy at the unspun end to circular anisotropy at the fast-spun end, enables the AFPT to behave like an all-fiber quarter-wave plate independent of the wavelength of operation. Power coupling between local eigenstates causes unique evolution of the polarization state along the fiber, and has been studied to gain insight into - as well as to understand detailed characteristics of -- the polarization transformation behavior. This has been graphically illustrated via plots of the relative power in these local eigenstates as a function of distance along the length of the fiber and plots of the extinction ratio of the output state of polarization (SOP) as a function of distance and the normalized spin rate. Deeper understanding of such polarization transformers has been further elucidated by quantitative calculations related to two crucial requirements for fabricating practical AFPT devices. Our calculations have also indicated that the polarization mode dispersion behaviour of the AFPT is much smaller than that of the original birefringent fiber. Finally, a specific AFPT was experimentally investigated at two widely-separated wavelengths (1310 nm and 1550 nm) of interest in telecommunications systems applications, further demonstrating and elucidating the broadband character of such AFPTs.

  5. Numerical simulation of two-phase flow around flatwater competition kayak design-evolution models.

    Science.gov (United States)

    Mantha, Vishveshwar R; Silva, António J; Marinho, Daniel A; Rouboa, Abel I

    2013-06-01

    The aim of the current study was to analyze the hydrodynamics of three kayaks: 97-kg-class, single-rower, flatwater sports competition, full-scale design evolution models (Nelo K1 Vanquish LI, LII, and LIII) of M.A.R. Kayaks Lda., Portugal, which are among the fastest frontline kayaks. The effect of kayak design transformation on kayak hydrodynamics performance was studied by the application of computational fluid dynamics (CFD). The steady-state CFD simulations where performed by application of the k-omega turbulent model and the volume-of-fluid method to obtain two-phase flow around the kayaks. The numerical result of viscous, pressure drag, and coefficients along with wave drag at individual average race velocities was obtained. At an average velocity of 4.5 m/s, the reduction in drag was 29.4% for the design change from LI to LII and 15.4% for the change from LII to LIII, thus demonstrating and reaffirming a progressive evolution in design. In addition, the knowledge of drag hydrodynamics presented in the current study facilitates the estimation of the paddling effort required from the athlete during progression at different race velocities. This study finds an application during selection and training, where a coach can select the kayak with better hydrodynamics.

  6. Evolution dynamics of a model for gene duplication under adaptive conflict

    Science.gov (United States)

    Ancliff, Mark; Park, Jeong-Man

    2014-06-01

    We present and solve the dynamics of a model for gene duplication showing escape from adaptive conflict. We use a Crow-Kimura quasispecies model of evolution where the fitness landscape is a function of Hamming distances from two reference sequences, which are assumed to optimize two different gene functions, to describe the dynamics of a mixed population of individuals with single and double copies of a pleiotropic gene. The evolution equations are solved through a spin coherent state path integral, and we find two phases: one is an escape from an adaptive conflict phase, where each copy of a duplicated gene evolves toward subfunctionalization, and the other is a duplication loss of function phase, where one copy maintains its pleiotropic form and the other copy undergoes neutral mutation. The phase is determined by a competition between the fitness benefits of subfunctionalization and the greater mutational load associated with maintaining two gene copies. In the escape phase, we find a dynamics of an initial population of single gene sequences only which escape adaptive conflict through gene duplication and find that there are two time regimes: until a time t* single gene sequences dominate, and after t* double gene sequences outgrow single gene sequences. The time t* is identified as the time necessary for subfunctionalization to evolve and spread throughout the double gene sequences, and we show that there is an optimum mutation rate which minimizes this time scale.

  7. Petrologic Modeling of Magmatic Evolution in The Elysium Volcanic Province

    Science.gov (United States)

    Susko, D.; Karunatillake, S.; Hood, D.

    2017-12-01

    The Elysium Volcanic Province (EVP) on Mars is a massive expanse of land made up of many hundreds of lava flows of various ages1. The variable surface ages within this volcanic province have distinct elemental compositions based on the derived values from the Gamma Ray Spectrometer (GRS) suite2. Without seismic data or ophiolite sequences on Mars, the compositions of lavas on the surface provide some of the only information to study the properties of the interior of the planet. The Amazonian surface age and isolated nature of the EVP in the northern lowlands of Mars make it ideal for analyzing the mantle beneath Elysium during the most recent geologic era on Mars. The MELTS algorithm is one of the most commonly used programs for simulating compositions and mineral phases of basaltic melt crystallization3. It has been used extensively for both terrestrial applications4 and for other planetary bodies3,5. The pMELTS calibration of the algorithm allows for higher pressure (10-30 kbars) regimes, and is more appropriate for modeling melt compositions and equilibrium conditions for a source within the martian mantle. We use the pMELTS program to model how partial melting of the martian mantle could evolve magmas into the surface compositions derived from the GRS instrument, and how the mantle beneath Elysium has changed over time. We attribute changes to lithospheric loading by long term, episodic volcanism within the EVP throughout its history. 1. Vaucher, J. et al. The volcanic history of central Elysium Planitia: Implications for martian magmatism. Icarus 204, 418-442 (2009). 2. Susko, D. et al. A record of igneous evolution in Elysium, a major martian volcanic province. Scientific Reports 7, 43177 (2017). 3. El Maarry, M. R. et al. Gamma-ray constraints on the chemical composition of the martian surface in the Tharsis region: A signature of partial melting of the mantle? Journal of Volcanology and Geothermal Research 185, 116-122 (2009). 4. Ding, S. & Dasgupta, R. The

  8. Confronting Models of Massive Star Evolution and Explosions with Remnant Mass Measurements

    Science.gov (United States)

    Raithel, Carolyn A.; Sukhbold, Tuguldur; Özel, Feryal

    2018-03-01

    The mass distribution of compact objects provides a fossil record that can be studied to uncover information on the late stages of massive star evolution, the supernova explosion mechanism, and the dense matter equation of state. Observations of neutron star masses indicate a bimodal Gaussian distribution, while the observed black hole mass distribution decays exponentially for stellar-mass black holes. We use these observed distributions to directly confront the predictions of stellar evolution models and the neutrino-driven supernova simulations of Sukhbold et al. We find strong agreement between the black hole and low-mass neutron star distributions created by these simulations and the observations. We show that a large fraction of the stellar envelope must be ejected, either during the formation of stellar-mass black holes or prior to the implosion through tidal stripping due to a binary companion, in order to reproduce the observed black hole mass distribution. We also determine the origins of the bimodal peaks of the neutron star mass distribution, finding that the low-mass peak (centered at ∼1.4 M ⊙) originates from progenitors with M ZAMS ≈ 9–18 M ⊙. The simulations fail to reproduce the observed peak of high-mass neutron stars (centered at ∼1.8 M ⊙) and we explore several possible explanations. We argue that the close agreement between the observed and predicted black hole and low-mass neutron star mass distributions provides new, promising evidence that these stellar evolution and explosion models capture the majority of relevant stellar, nuclear, and explosion physics involved in the formation of compact objects.

  9. COGNITIVE MODELING OF EPISTEMIC MENTAL STATES

    Directory of Open Access Journals (Sweden)

    Yurovitskaya, L.N.

    2017-03-01

    Full Text Available Epistemic states of mind, connected with the cognitive activity of a man, are aimed not only at apprehending the world around us, but also at the process of this apprehension. A very important step on this way is an attempt to model these states and processes in terms of formal logics and semantics, irrespective of the language of cognition. The article presents the idea of how formal logical and linguistic modeling of the process of thinking shows the correlation and the interdependence of semantic units connected with mental activities of human brain. The basic notions of the conceptual field of cognition are presented in the article

  10. Epigenetics and Evolution: Transposons and the Stochastic Epigenetic Modification Model

    Directory of Open Access Journals (Sweden)

    Sergio Branciamore

    2015-04-01

    Full Text Available In addition to genetic variation, epigenetic variation and transposons can greatly affect the evolutionary fitnesses landscape and gene expression. Previously we proposed a mathematical treatment of a general epigenetic variation model that we called Stochastic Epigenetic Modification (SEM model. In this study we follow up with a special case, the Transposon Silencing Model (TSM, with, once again, emphasis on quantitative treatment. We have investigated the evolutionary effects of epigenetic changes due to transposon (T insertions; in particular, we have considered a typical gene locus A and postulated that (i the expression level of gene A depends on the epigenetic state (active or inactive of a cis- located transposon element T, (ii stochastic variability in the epigenetic silencing of T occurs only in a short window of opportunity during development, (iii the epigenetic state is then stable during further development, and (iv the epigenetic memory is fully reset at each generation. We develop the model using two complementary approaches: a standard analytical population genetics framework (di usion equations and Monte-Carlo simulations. Both approaches led to similar estimates for the probability of fixation and time of fixation of locus TA with initial frequency P in a randomly mating diploid population of effective size Ne. We have ascertained the e ect that ρ, the probability of transposon Modification during the developmental window, has on the population (species. One of our principal conclusions is that as ρ increases, the pattern of fixation of the combined TA locus goes from "neutral" to "dominant" to "over-dominant". We observe that, under realistic values of ρ, epigenetic Modifications can provide an e cient mechanism for more rapid fixation of transposons and cis-located gene alleles. The results obtained suggest that epigenetic silencing, even if strictly transient (being reset at each generation, can still have signi cant

  11. A Model of Mental State Transition Network

    Science.gov (United States)

    Xiang, Hua; Jiang, Peilin; Xiao, Shuang; Ren, Fuji; Kuroiwa, Shingo

    Emotion is one of the most essential and basic attributes of human intelligence. Current AI (Artificial Intelligence) research is concentrating on physical components of emotion, rarely is it carried out from the view of psychology directly(1). Study on the model of artificial psychology is the first step in the development of human-computer interaction. As affective computing remains unpredictable, creating a reasonable mental model becomes the primary task for building a hybrid system. A pragmatic mental model is also the fundament of some key topics such as recognition and synthesis of emotions. In this paper a Mental State Transition Network Model(2) is proposed to detect human emotions. By a series of psychological experiments, we present a new way to predict coming human's emotions depending on the various current emotional states under various stimuli. Besides, people in different genders and characters are taken into consideration in our investigation. According to the psychological experiments data derived from 200 questionnaires, a Mental State Transition Network Model for describing the transitions in distribution among the emotions and relationships between internal mental situations and external are concluded. Further more the coefficients of the mental transition network model were achieved. Comparing seven relative evaluating experiments, an average precision rate of 0.843 is achieved using a set of samples for the proposed model.

  12. The evolution of a coupled ice shelf-ocean system under different climate states

    Science.gov (United States)

    Grosfeld, Klaus; Sandhäger, Henner

    2004-07-01

    Based on a new approach for coupled applications of an ice shelf model and an ocean general circulation model, we investigate the evolution of an ice shelf-ocean system and its sensitivity to changed climatic boundary conditions. Combining established 3D models into a coupled model system enabled us to study the reaction and feedbacks of each component to changes at their interface, the ice shelf base. After calculating the dynamics for prescribed initial ice shelf and bathymetric geometries, the basal mass balance determines the system evolution. In order to explore possible developments for given boundary conditions, an idealized geometry has been chosen, reflecting basic features of the Filchner-Ronne Ice Shelf, Antarctica. The model system is found to be especially sensitive in regions where high ablation or accretion rates occur. Ice Shelf Water formation as well as the build up of a marine ice body, resulting from accretion of marine ice, is simulated, indicating strong interaction processes. To improve consistency between modeled and observed ice shelf behavior, we incorporate the typical cycle of steady ice front advance and sudden retreat due to tabular iceberg calving in our time-dependent simulations. Our basic hypothesis is that iceberg break off is associated with abrupt crack propagation along elongated anomalies of the inherent stress field of the ice body. This new concept yields glaciologically plausible results and represents an auspicious basis for the development of a thorough calving criterion. Experiments under different climatic conditions (ocean warming of 0.2 and 0.5 °C and doubled surface accumulation rates) show the coupled model system to be sensitive especially to ocean warming. Increased basal melt rates of 100% for the 0.5 °C ocean warming scenario and an asymmetric development of ice shelf thicknesses suggest a high vulnerability of ice shelf regions, which represent pivotal areas between the Antarctic Ice Sheet and the Southern

  13. A Model of Solid State Gas Sensors

    Science.gov (United States)

    Woestman, J. T.; Brailsford, A. D.; Shane, M.; Logothetis, E. M.

    1997-03-01

    Solid state gas sensors are widely used to measure the concentrations of gases such as CO, CH_4, C_3H_6, H_2, C_3H8 and O2 The applications of these sensors range from air-to-fuel ratio control in combustion processes including those in automotive engines and industrial furnaces to leakage detection of inflammable and toxic gases in domestic and industrial environments. As the need increases to accurately measure smaller and smaller concentrations, problems such as poor selectivity, stability and response time limit the use of these sensors. In an effort to overcome some of these limitations, a theoretical model of the transient behavior of solid state gas sensors has been developed. In this presentation, a model for the transient response of an electrochemical gas sensor to gas mixtures containing O2 and one reducing species, such as CO, is discussed. This model accounts for the transport of the reactive species to the sampling electrode, the catalyzed oxidation/reduction reaction of these species and the generation of the resulting electrical signal. The model will be shown to reproduce the results of published steady state models and to agree with experimental steady state and transient data.

  14. Geochronological synthesis of Bahia state and the crustal evolution, based in evolution diagram of Sr and initial rate of Sr87/Sr86

    International Nuclear Information System (INIS)

    Sato, K.

    1986-01-01

    The crustal evolution of the ancient terrains of the State of Bahia, Brazil, is attempted with the aid of Sr isotopic results as natural tracers. Some Nd and Pb isotopic data are also available, and support the main conclusions based on Sr evolution diagrams. The analysis of the Sr evolution diagrams shows that the Archean Terrains are mainly formed by accretion from mantle-derived material, but crustal reworking is indicated by the high initial 87 Sr/ 86 Sr value of the Jequie Complex. The Transamazonian mobile belt include both types of materials, but the 87 Sr/ 86 Sr value, generally lower than those of the Jequie Complex, markes improbable a direct derivation. During Middle and Late Proterozoic, the continental crust was already well consolidated, and reworking of crustal material predominated within the Espinhaco and Brasiliano folded systems [pt

  15. Computational Modeling of Microstructural-Evolution in AISI 1005 Steel During Gas Metal Arc Butt Welding

    Science.gov (United States)

    2013-05-01

    H.K.D.H. Bhadeshia, A Model for the Microstruc- ture of Some Advanced Bainitic Steels , Mater. Trans., 1991, 32, p 689–696 19. G.J. Davies and J.G. Garland...REPORT Computational Modeling of Microstructural-Evolution in AISI 1005 Steel During Gas Metal Arc Butt Welding 14. ABSTRACT 16. SECURITY...Computational Modeling of Microstructural-Evolution in AISI 1005 Steel During Gas Metal Arc Butt Welding Report Title ABSTRACT A fully coupled (two-way

  16. Modeling Marek's disease virus transmission: A framework for evaluating the impact of farming practices and evolution

    OpenAIRE

    David A. Kennedy; Patricia A. Dunn; Andrew F. Read

    2018-01-01

    Marek's disease virus (MDV) is a pathogen of chickens whose control has twice been undermined by pathogen evolution. Disease ecology is believed to be the main driver of this evolution, yet mathematical models of MDV disease ecology have never been confronted with data to test their reliability. Here, we develop a suite of MDV models that differ in the ecological mechanisms they include. We fit these models with maximum likelihood using iterated filtering in ‘pomp’ to data on MDV concentratio...

  17. Quantum time evolution of a closed Friedmann model

    CERN Document Server

    Hinterleitner, F

    2002-01-01

    We consider a quantized dust-filled closed Friedmann universe in Ashtekar-type variables. Due to the presence of matter, the 'timelessness problem' of quantum gravity can be solved in this case by using the following approach to the Hamiltonian operator. 1. The arising Wheeler-DeWitt equation appears as an eigenvalue equation for discrete values of the total mass. 2. Its gravitational part is considered as the generator of the time evolution of geometry. 3. Superpositions of different eigenfunctions with time behaviour governed by the corresponding eigenvalues of mass are admitted. Following these lines, a time evolution with a correct classical limit is obtained.

  18. Reuleaux models at St. Petersburg State University

    Science.gov (United States)

    Kuteeva, G. A.; Sinilshchikova, G. A.; Trifonenko, B. V.

    2018-05-01

    Franz Reuleaux (1829 - 1905) is a famous mechanical engineer, a Professor of the Berlin Royal Technical Academy. He became widely known as an engineer-scientist, a Professor and industrial consultant, education reformer and leader of the technical elite of Germany. He directed the design and manufacture of over 300 models of simple mechanisms. They were sold to many famous universities for pedagogical and scientific purposes. Today, the most complete set is at Cornell University, College of Engineering. In this article we discuss the history, the modern state and our using the Reuleaux models that survived at St. Petersburg State University for educational purposes. We present description of certain models and our electronic resource with these models. We provide the information of similar electronic resources from other universities.

  19. Multi-state modeling of biomolecules.

    Directory of Open Access Journals (Sweden)

    Melanie I Stefan

    2014-09-01

    Full Text Available Multi-state modeling of biomolecules refers to a series of techniques used to represent and compute the behavior of biological molecules or complexes that can adopt a large number of possible functional states. Biological signaling systems often rely on complexes of biological macromolecules that can undergo several functionally significant modifications that are mutually compatible. Thus, they can exist in a very large number of functionally different states. Modeling such multi-state systems poses two problems: the problem of how to describe and specify a multi-state system (the "specification problem" and the problem of how to use a computer to simulate the progress of the system over time (the "computation problem". To address the specification problem, modelers have in recent years moved away from explicit specification of all possible states and towards rule-based formalisms that allow for implicit model specification, including the κ-calculus, BioNetGen, the Allosteric Network Compiler, and others. To tackle the computation problem, they have turned to particle-based methods that have in many cases proved more computationally efficient than population-based methods based on ordinary differential equations, partial differential equations, or the Gillespie stochastic simulation algorithm. Given current computing technology, particle-based methods are sometimes the only possible option. Particle-based simulators fall into two further categories: nonspatial simulators, such as StochSim, DYNSTOC, RuleMonkey, and the Network-Free Stochastic Simulator (NFSim, and spatial simulators, including Meredys, SRSim, and MCell. Modelers can thus choose from a variety of tools, the best choice depending on the particular problem. Development of faster and more powerful methods is ongoing, promising the ability to simulate ever more complex signaling processes in the future.

  20. Time evolution of the coarse-graining-smoothed Wigner operator in an amplitude dissipative channel: from a pure state to a mixed state

    International Nuclear Information System (INIS)

    He, Rui; Fan, Hong-yi

    2014-01-01

    Based on the solution to the master equation of the density operator describing the amplitude dissipative channel, we derive the time evolution law of the coarse-graining-smoothed Wigner operator in this channel, which demonstrates how an initial pure state evolves into a mixed state, exhibiting decoherence

  1. Explicit state representation and the ATLAS event data model: theory and practice

    International Nuclear Information System (INIS)

    Nowak, M; Snyder, S; Cranmer, K; Malon, D; Gemmeren, P v; Schaffer, A; Binet, S

    2008-01-01

    In anticipation of data taking, ATLAS has undertaken a program of work to develop an explicit state representation of the experiment's complex transient event data model. This effort has provided both an opportunity to consider explicitly the structure, organization, and content of the ATLAS persistent event store before writing tens of petabytes of data (replacing simple streaming, which uses the persistent store as a core dump of transient memory), and a locus for support of event data model evolution, including significant refactoring, beyond the automatic schema evolution capabilities of underlying persistence technologies. ATLAS has encountered the need for such non-trivial schema evolution on several occasions already. This paper describes the state representation strategy (transient/persistent separation) and its implementation, including both the payoffs that ATLAS has seen (significant and sometimes surprising space and performance improvements, the extra layer notwithstanding, and extremely general schema evolution support) and the costs (additional and relatively pervasive additional infrastructure development and maintenance). The paper further discusses how these costs are mitigated, and how ATLAS is able to implement this strategy without losing the ability to take advantage of the (improving!) automatic schema evolution capabilities of underlying technology layers when appropriate. Implications of state representations for direct ROOT browsability, and current strategies for associating physics analysis views with such state representations, are also described

  2. The Evolution of the Theory and Practice of State Regulation of Addictive Goods Markets

    Directory of Open Access Journals (Sweden)

    Roman Yuryevich Skokov

    2016-03-01

    Full Text Available The article discusses the evolution of state regulation of the market of addictive goods and services in the context of the periodization of ideas about the role of the state in the economy in general, in historical and economic era, in the formation of the species of addictive goods markets. In the age of mercantilism the sphere of regulation of addictive goods markets was not the subject of attention of economists, but in practice there is an idea of the need for state protectionism. During its criticism in the framework of the theory of physiocrats and in the beginning of the classical school, alcohol products become a subject of research of economists, as the major source of budgetary funds. The abolition of serfdom, the development of private industrial activity, changing the farming tax system to the excise tax, indicate the penetration of traditional liberal principles in domestic economy in the field of addictive goods. The German historical schools focused on the active role of the state with respect to national peculiarities of the economy, found support and development in the works of Russian scientists that support the alcohol and tobacco monopoly. In the Soviet period the principles of Marxist political economy were formed on the basis of total nationalization of production and distribution of allowed addictive goods. The margin school is characterized by psychological interpretation of economic processes in the field of addictive goods under the conditions of perfect competition, in particular the role of consumers in the pricing. In the period of theoretical struggle of monetarism against keynesianism, which coincided with the drug boom, there were areas of economics of crime and punishment, drugs. In the neoliberalism period the antiprohibitionist movement was formed in the field of addictive goods. Changing some postulates of neoclassical economics by neo-institutional economic theory contributed to the development of empirical

  3. Model of evolution of radioactive waste repositories and their influence on the resource-ecological safety of an adjoining territories

    International Nuclear Information System (INIS)

    Angelova, R.; Sandul, G.A.; Sen'ko, T.Ya.

    2002-01-01

    In this paper it is considered the mathematical model of evolution of radioactive waste (RAW) repositories and their influence on the resource-ecological safety (RES) and sustainable development of an adjoining territories. Heart of considered model consists of that RAW repository is considered as a system with two processes proceeding in parallel: deterioration of repository buildings, equipment etc. enlarging resource-ecological danger (RED) on account of probability increase (risk increase) of emergency conditions; natural decay of RAW being in repository that lead to RED decrease. Considered model allows to learn RAW repositories evolution in given time interval and to analyze their behavior at its different stages depending on state of repositories, e.g., their modernization or other events as well as to define periods of RAW repositories peak danger for environment

  4. Solvable model of quantum microcanonical states

    International Nuclear Information System (INIS)

    Bender, Carl M; Brody, Dorje C; Hook, Daniel W

    2005-01-01

    This letter examines the consequences of a recently proposed modification of the postulate of equal a priori probability in quantum statistical mechanics. This modification, called the quantum microcanonical postulate (QMP), asserts that for a system in microcanonical equilibrium all pure quantum states having the same energy expectation value are realized with equal probability. A simple model of a quantum system that obeys the QMP and that has a nondegenerate spectrum with equally spaced energy eigenvalues is studied. This model admits a closed-form expression for the density of states in terms of the energy eigenvalues. It is shown that in the limit as the number of energy levels approaches infinity, the expression for the density of states converges to a δ function centred at the intermediate value (E max + E min )/2 of the energy. Determining this limit requires an elaborate asymptotic study of an infinite sum whose terms alternate in sign. (letter to the editor)

  5. The Jukes-Cantor Model of Molecular Evolution

    Science.gov (United States)

    Erickson, Keith

    2010-01-01

    The material in this module introduces students to some of the mathematical tools used to examine molecular evolution. This topic is standard fare in many mathematical biology or bioinformatics classes, but could also be suitable for classes in linear algebra or probability. While coursework in matrix algebra, Markov processes, Monte Carlo…

  6. Modeling Wind Wave Evolution from Deep to Shallow Water

    Science.gov (United States)

    2014-09-30

    W.H. Hui, 1979; Nonlinear energy transfer in narrow gravity wave spectrum. Proc. Roy. Soc. London A368, 239–265. Gagnaire-Renou, E., M. Benoit , and P...at the 2013 WISE meeting, Camp Springs, MA , USA. Smit P. B. and T. T. Janssen, 2013; The evolution of inhomogeneous wave statistics through a

  7. What Characterise the Nordic Welfare State Model

    DEFF Research Database (Denmark)

    Greve, Bent

    2007-01-01

    The main distinctive characteristics of the Nordic welfare states are presented. These include full employment, high degree of equality, a high level of taxes and public sector spending. The Nordic countries are compared to other European countries. The conclusion being that the Nordic Model...... is here to stay, although a movement in a European direction is underway....

  8. A Knowledge Discovery from POS Data using State Space Models

    Science.gov (United States)

    Sato, Tadahiko; Higuchi, Tomoyuki

    The number of competing-brands changes by new product's entry. The new product introduction is endemic among consumer packaged goods firm and is an integral component of their marketing strategy. As a new product's entry affects markets, there is a pressing need to develop market response model that can adapt to such changes. In this paper, we develop a dynamic model that capture the underlying evolution of the buying behavior associated with the new product. This extends an application of a dynamic linear model, which is used by a number of time series analyses, by allowing the observed dimension to change at some point in time. Our model copes with a problem that dynamic environments entail: changes in parameter over time and changes in the observed dimension. We formulate the model with framework of a state space model. We realize an estimation of the model using modified Kalman filter/fixed interval smoother. We find that new product's entry (1) decreases brand differentiation for existing brands, as indicated by decreasing difference between cross-price elasticities; (2) decreases commodity power for existing brands, as indicated by decreasing trend; and (3) decreases the effect of discount for existing brands, as indicated by a decrease in the magnitude of own-brand price elasticities. The proposed framework is directly applicable to other fields in which the observed dimension might be change, such as economic, bioinformatics, and so forth.

  9. Energy-Aware Topology Evolution Model with Link and Node Deletion in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Xiaojuan Luo

    2012-01-01

    Full Text Available Based on the complex network theory, a new topological evolving model is proposed. In the evolution of the topology of sensor networks, the energy-aware mechanism is taken into account, and the phenomenon of change of the link and node in the network is discussed. Theoretical analysis and numerical simulation are conducted to explore the topology characteristics and network performance with different node energy distribution. We find that node energy distribution has the weak effect on the degree distribution P(k that evolves into the scale-free state, nodes with more energy carry more connections, and degree correlation is nontrivial disassortative. Moreover, the results show that, when nodes energy is more heterogeneous, the network is better clustered and enjoys higher performance in terms of the network efficiency and the average path length for transmitting data.

  10. The evolution of brachiation in ateline primates, ancestral character states and history.

    Science.gov (United States)

    Jones, Andrea L

    2008-10-01

    This study examines how brachiation locomotion evolved in ateline primates using recently-developed molecular phylogenies and character reconstruction algorithms, and a newly-collected dataset including the fossils Protopithecus, Caipora, and Cebupithecia. Fossils are added to two platyrrhine molecular phylogenies to create several phylogenetic scenarios. A generalized least squares algorithm reconstructs ateline and atelin ancestral character states for 17 characters that differentiate between ateline brachiators and nonbrachiators. Histories of these characters are mapped out on these phylogenies, producing two scenarios of ateline brachiation evolution that have four commonalities: First, many characters change towards the Ateles condition on the ateline stem lineage before Alouatta splits off from the atelins, suggesting that an ateline energy-maximizing strategy began before the atelines diversified. Second, the ateline last common ancestor is always reconstructed as an agile quadruped, usually with suspensory abilities. It is never exactly like Alouatta and many characters reverse and change towards the Alouatta condition after Alouatta separates from the atelins. Third, most characters undergo homoplastic change in all ateline lineages, especially on the Ateles and Brachyteles terminal branches. Fourth, ateline character evolution probably went through a hindlimb suspension with tail-bracing phase. The atelines most likely diversified via a quick adaptive radiation, with bursts of punctuated change occurring in their postcranial skeletons, due to changing climatic conditions, which may have caused competition among the atelines and between atelines and pitheciines.

  11. FEDERAL SUPPORT OF SCIENTIFIC INQUIRY IN THE UNITED STATES: CURRENT EVOLUTION UNDER THE POLITICAL STRUGGLE

    Directory of Open Access Journals (Sweden)

    I. A. Istomin

    2016-01-01

    Full Text Available 2000’s and 2010’s witnessed diminishing margin of the United States in science and technology. Meanwhile, the U.S. remains a clear leader in this fi eld. Major driving force of the country’s success in the second half of the ХХ century remained assertive federal science policy. The article seeks to identify major trends in evolution of the U.S. science policy and the reasons behind relative decline of the level of budget support of the scientifi c research. The author studies evolution of the policies of George Bush and Barack Obama, as well as the views of Democrats and Republicans in the House of Representatives and the Senate. The article also examines the input into the federal policy of the governmental bodies, which are directly responsible for its implementation, as well as non-governmental organizations, which seek to advocate interests of scientists; it studies rising competition between the executive authorities and legislators for the recognition as a major champion of the academic community as well as American Recovery and Reinvestment Act.

  12. Competing States in the t-J Model: Uniform d-Wave State versus Stripe State versus Stripe State

    NARCIS (Netherlands)

    Corboz, P.R.; Rice, T.M.; Troyer, M.

    2014-01-01

    Variational studies of the t-J model on the square lattice based on infinite projected-entangled pair states confirm an extremely close competition between a uniform d-wave superconducting state and different stripe states. The site-centered stripe with an in-phase d-wave order has an equal or only

  13. An Evaluation of Models of Bentonite Pore Water Evolution

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David; Watson, Claire; Wilson, James (Quintessa Ltd, Henley-on-Thames (United Kingdom)); Arthur, Randy (Monitor Scientific LLC, Denver, CO (United States))

    2010-01-15

    The determination of a bentonite pore water composition and understanding its evolution of with time underpins many radioactive waste disposal issues, such as buffer erosion, canister corrosion, and radionuclide solubility, sorption, and diffusion, inter alia. The usual approach to modelling clay pore fluids is based primarily around assumed chemical equilibrium between Na+, K+, Ca2+, and Mg2+ aqueous species and ion exchange sites on montmorillonite, but also includes protonation- deprotonation of clay edge surface sites, and dissolution-precipitation of the trace mineral constituents, calcite and gypsum. An essential feature of this modelling approach is that clay hydrolysis reactions (i.e. dissolution of the aluminosilicate octahedral and tetrahedral sheets of montmorillonite) are ignored. A consequence of the omission of clay hydrolysis reactions from bentonite pore fluid models is that montmorillonite is preserved indefinitely in the near-field system, even over million-year timescales. Here, we investigate the applicability of an alternative clay pore fluid model, one that incorporates clay hydrolysis reactions as an integral component and test it against well-characterised laboratory experimental data, where key geochemical parameters, Eh and pH, have been measured directly in compacted bentonite. Simulations have been conducted using a range of computer codes to test the applicability of this alternative model. Thermodynamic data for MX-80 smectite used in the calculations were estimated using two different methods. Simulations of 'end-point' pH measurements in batch bentonite-water slurry experiments showed different pH values according to the complexity of the system studied. The most complete system investigated revealed pH values were a strong function of partial pressure of carbon dioxide, with pH increasing with decreasing PCO{sub 2} (log PCO{sub 2} values ranging from -3.5 to -7.5 bars produced pH values ranging from 7.9 to 9.6). A second

  14. Microstructure evolution during cyclic tests on EUROFER 97 at room temperature. TEM observation and modelling

    Czech Academy of Sciences Publication Activity Database

    Giordana, M. F.; Giroux, P. F.; Alvarez; Armas, I.; Sauzay, M.; Armas, A.; Kruml, Tomáš

    2012-01-01

    Roč. 550, JUL (2012), s. 103-111 ISSN 0921-5093 Institutional support: RVO:68081723 Keywords : martensitic steels * softening behaviour * microstructural evolution * modelling Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.108, year: 2012

  15. Numerical study of the evolution of a magnetized plasma by means of a hybrid model

    Energy Technology Data Exchange (ETDEWEB)

    Dinu, L [Institutul de Matematica, Bucharest (Romania); Vlad, M [Institutul de Fizica si Tehnologia Aparatelor cu Radiatii, Bucharest (Romania)

    1979-01-01

    A numerical solution of the Vlasov-fluid model describing a time and space plasma evolution is presented. This should be compared with J.P. Frjedberg's analysis (1), (2) which provides growth rates for instabilities and some stability criteria.

  16. Gas-evolution oscillators. 10. A model based on a delay equation

    Energy Technology Data Exchange (ETDEWEB)

    Bar-Eli, K.; Noyes, R.M. [Univ. of Oregon, Eugene, OR (United States)

    1992-09-17

    This paper develops a simplified method to model the behavior of a gas-evolution oscillator with two differential delay equations in two unknowns consisting of the population of dissolved molecules in solution and the pressure of the gas.

  17. Gas-evolution oscillators. 10. A model based on a delay equation

    International Nuclear Information System (INIS)

    Bar-Eli, K.; Noyes, R.M.

    1992-01-01

    This paper develops a simplified method to model the behavior of a gas-evolution oscillator with two differential delay equations in two unknowns consisting of the population of dissolved molecules in solution and the pressure of the gas

  18. Creation and evolution of excited states in α particle tracks in anthracene crystals

    International Nuclear Information System (INIS)

    Klein, G.

    1977-01-01

    The kinematics of excited states in anthracene crystals bombarded by 5MeV α particles is studied. The elementary processes which account for the transitions from the primary excited states to the lowest singlet S 1 and triplet T 1 excited states is described. The equation governing the evolution of the S 1 and T 1 excitons in the α particle track are then solved, and the scintillation decay curve is calculated. This calculated result is in good agreement with all available experimental results. The experimental part of this work are scintillation decay curves measurements. The scintillation decay was measured between 0.5nsec and 40μsec. The influence of the initial very fast singlet excitons quenching by triplet excitons can be seen in the beginning of scintillation. The delayed component is described by the triplet excitons kinematics. The magnetic field effect on the scintillation was investigated. This effect is attributed to an effect on the T 1 -T 1 annihilation and an effect on the triplet excitons quenching by radicals which are formed in the α particle track

  19. Prior states: evolution of composition and color in two Barnett Newman paintings

    Science.gov (United States)

    Epley, Bradford A.; Rogge, Corina E.

    2015-11-01

    The color field paintings of Barnett Newman, one of the great American abstract expressionist painters, are seminal works of the modern era. They feature large flat fields of vibrant colors intended to allow the viewer to connect with the paintings in immediate, visceral ways. Despite the apparent simplicity of his compositions, Newman considered himself an intuitive painter and allowed his compositions to evolve during the painting process. Two paintings in the Menil Collection, Untitled 2 (1950) and Unfinished Painting [Blue and Brown 1970— #2] (1970) display visual evidence of former states, but attempts to elucidate earlier compositions by X-radiography were inconclusive due to the lack of contrast in paint densities. We applied limited sampling and used a handheld X-ray fluorescence spectrometer in a `scanning' manner to determine the color and composition of the previous states of these paintings to help us better understand their evolution. Newman altered his initial cadmium red and alizarin composition in Untitled 2 (1950) by overpainting the alizarin region with a wider band of Mars black paint. He then modulated the surface of the black by partially covering it with a carbonaceous black with a different gloss. For Unfinished Painting [Blue and Brown 1970— #2] (1970), Newman not only changed the cadmium red to an umber but simplified the composition, removing multiple zips and refining it to its current monumental state. This evidence of Newman's decision-making processes permits a tantalizing glimpse of the artist consistently looking both ahead and backward, experimenting and revisiting.

  20. A state-space-based prognostics model for lithium-ion battery degradation

    International Nuclear Information System (INIS)

    Xu, Xin; Chen, Nan

    2017-01-01

    This paper proposes to analyze the degradation of lithium-ion batteries with the sequentially observed discharging profiles. A general state-space model is developed in which the observation model is used to approximate the discharging profile of each cycle, the corresponding parameter vector is treated as the hidden state, and the state-transition model is used to track the evolution of the parameter vector as the battery ages. The EM and EKF algorithms are adopted to estimate and update the model parameters and states jointly. Based on this model, we construct prediction on the end of discharge times for unobserved cycles and the remaining useful cycles before the battery failure. The effectiveness of the proposed model is demonstrated using a real lithium-ion battery degradation data set. - Highlights: • Unifying model for Li-Ion battery SOC and SOH estimation. • Extended Kalman filter based efficient inference algorithm. • Using voltage curves in discharging to have wide validity.

  1. A simple model for the microstructural evolution of solids under irradiation

    International Nuclear Information System (INIS)

    Valentin, P.P.; Martin, G.

    1982-01-01

    The coupled evolutions of the void and dislocation populations in crystals under high-temperature irradiation are studied by a simple heuristic theoretical approach: rate equations are used for describing both defect concentrations and microstructural variables, and the trajectories of the point representative of the microstructure in the appropriate state space are studied. Qualitatively different microstructural evolutions are found depending on the irradiation flux and temperature. Non-trivial behaviours are revealed such as: transient swelling, effect of cold work on the incubation dose for swelling, large dose divergence of evolutions which looked similar at low dose (which should result in large swelling heterogeneities) and radiation-enhanced sintering. (author)

  2. Evolution dynamics modeling and simulation of logistics enterprise's core competence based on service innovation

    Science.gov (United States)

    Yang, Bo; Tong, Yuting

    2017-04-01

    With the rapid development of economy, the development of logistics enterprises in China is also facing a huge challenge, especially the logistics enterprises generally lack of core competitiveness, and service innovation awareness is not strong. Scholars in the process of studying the core competitiveness of logistics enterprises are mainly from the perspective of static stability, not from the perspective of dynamic evolution to explore. So the author analyzes the influencing factors and the evolution process of the core competence of logistics enterprises, using the method of system dynamics to study the cause and effect of the evolution of the core competence of logistics enterprises, construct a system dynamics model of evolution of core competence logistics enterprises, which can be simulated by vensim PLE. The analysis for the effectiveness and sensitivity of simulation model indicates the model can be used as the fitting of the evolution process of the core competence of logistics enterprises and reveal the process and mechanism of the evolution of the core competence of logistics enterprises, and provide management strategies for improving the core competence of logistics enterprises. The construction and operation of computer simulation model offers a kind of effective method for studying the evolution of logistics enterprise core competence.

  3. Backward modelling of the subsidence evolution of the Colorado Basin, offshore Argentina and its relation to the evolution of the conjugate Orange Basin, offshore SW Africa

    Science.gov (United States)

    Dressel, Ingo; Scheck-Wenderoth, Magdalena; Cacace, Mauro

    2017-10-01

    In this study we focus on reconstructing the post-rift subsidence evolution of the Colorado Basin, offshore Argentina. We make use of detailed structural information about its present-day configuration of the sedimentary infill and the crystalline crust. This information is used as input in a backward modelling approach which relies on the assumption of local isostasy to reconstruct the amount of subsidence as induced by the sedimentary load through different time stages. We also attempt a quantification of the thermal effects on the subsidence as induced by the rifting, here included by following the uniform stretching model of lithosphere thinning and exponentially cooling through time. Based on the available information about the present-day geological state of the system, our modelling results indicate a rather continuous post-rift subsidence for the Colorado Basin, and give no significant evidence of any noticeable uplift phase. In a second stage, we compare the post-rift evolution of the Colorado Basin with the subsidence evolution as constrained for its conjugate SW African passive margin, the Orange Basin. Despite these two basins formed almost coevally and therefore in a similar large scale geodynamic context, their post-rift subsidence histories differ. Based on this result, we discuss causative tectonic processes likely to provide an explanation to the observed differences. We therefore conclude that it is most probable that additional tectonic components, other than the ridge-push from the spreading of the South Atlantic Ocean, are required to explain the observed differences in the subsidence of the two basins along the conjugate passive margins. Such additional tectonic components might be related to a dynamic mantle component in the form of either plume activity (Africa) or a subducting slab and the presence of an ongoing compressional stress system as revealed for different areas in South America.

  4. Ups and Downs: Modeling the Visual Evolution of Fashion Trends with One-Class Collaborative Filtering

    OpenAIRE

    He, Ruining; McAuley, Julian

    2016-01-01

    Building a successful recommender system depends on understanding both the dimensions of people's preferences as well as their dynamics. In certain domains, such as fashion, modeling such preferences can be incredibly difficult, due to the need to simultaneously model the visual appearance of products as well as their evolution over time. The subtle semantics and non-linear dynamics of fashion evolution raise unique challenges especially considering the sparsity and large scale of the underly...

  5. An Analytical Model for the Evolution of the Protoplanetary Disks

    Energy Technology Data Exchange (ETDEWEB)

    Khajenabi, Fazeleh; Kazrani, Kimia; Shadmehri, Mohsen, E-mail: f.khajenabi@gu.ac.ir [Department of Physics, Faculty of Sciences, Golestan University, Gorgan 49138-15739 (Iran, Islamic Republic of)

    2017-06-01

    We obtain a new set of analytical solutions for the evolution of a self-gravitating accretion disk by holding the Toomre parameter close to its threshold and obtaining the stress parameter from the cooling rate. In agreement with the previous numerical solutions, furthermore, the accretion rate is assumed to be independent of the disk radius. Extreme situations where the entire disk is either optically thick or optically thin are studied independently, and the obtained solutions can be used for exploring the early or the final phases of a protoplanetary disk evolution. Our solutions exhibit decay of the accretion rate as a power-law function of the age of the system, with exponents −0.75 and −1.04 for optically thick and thin cases, respectively. Our calculations permit us to explore the evolution of the snow line analytically. The location of the snow line in the optically thick regime evolves as a power-law function of time with the exponent −0.16; however, when the disk is optically thin, the location of the snow line as a function of time with the exponent −0.7 has a stronger dependence on time. This means that in an optically thin disk inward migration of the snow line is faster than an optically thick disk.

  6. Ancestral state reconstructions require biological evidence to test evolutionary hypotheses: A case study examining the evolution of reproductive mode in squamate reptiles.

    Science.gov (United States)

    Griffith, Oliver W; Blackburn, Daniel G; Brandley, Matthew C; Van Dyke, James U; Whittington, Camilla M; Thompson, Michael B

    2015-09-01

    To understand evolutionary transformations it is necessary to identify the character states of extinct ancestors. Ancestral character state reconstruction is inherently difficult because it requires an accurate phylogeny, character state data, and a statistical model of transition rates and is fundamentally constrained by missing data such as extinct taxa. We argue that model based ancestral character state reconstruction should be used to generate hypotheses but should not be considered an analytical endpoint. Using the evolution of viviparity and reversals to oviparity in squamates as a case study, we show how anatomical, physiological, and ecological data can be used to evaluate hypotheses about evolutionary transitions. The evolution of squamate viviparity requires changes to the timing of reproductive events and the successive loss of features responsible for building an eggshell. A reversal to oviparity requires that those lost traits re-evolve. We argue that the re-evolution of oviparity is inherently more difficult than the reverse. We outline how the inviability of intermediate phenotypes might present physiological barriers to reversals from viviparity to oviparity. Finally, we show that ecological data supports an oviparous ancestral state for squamates and multiple transitions to viviparity. In summary, we conclude that the first squamates were oviparous, that frequent transitions to viviparity have occurred, and that reversals to oviparity in viviparous lineages either have not occurred or are exceedingly rare. As this evidence supports conclusions that differ from previous ancestral state reconstructions, our paper highlights the importance of incorporating biological evidence to evaluate model-generated hypotheses. © 2015 Wiley Periodicals, Inc.

  7. Developing, choosing and using landscape evolution models to inform field-based landscape reconstruction studies : Developing, choosing and using landscape evolution models

    NARCIS (Netherlands)

    Temme, A.j.a.m.; Armitage, J.; Attal, M.; Van Gorp, W.; Coulthard, T.j.; Schoorl, J.m.

    2017-01-01

    Landscape evolution models (LEMs) are an increasingly popular resource for geomorphologists as they can operate as virtual laboratories where the implications of hypotheses about processes over human to geological timescales can be visualized at spatial scales from catchments to mountain ranges.

  8. Markov chain modeling of evolution of strains in reinforced concrete flexural beams

    Directory of Open Access Journals (Sweden)

    Anoop, M. B.

    2012-09-01

    Full Text Available From the analysis of experimentally observed variations in surface strains with loading in reinforced concrete beams, it is noted that there is a need to consider the evolution of strains (with loading as a stochastic process. Use of Markov Chains for modeling stochastic evolution of strains with loading in reinforced concrete flexural beams is studied in this paper. A simple, yet practically useful, bi-level homogeneous Gaussian Markov Chain (BLHGMC model is proposed for determining the state of strain in reinforced concrete beams. The BLHGMC model will be useful for predicting behavior/response of reinforced concrete beams leading to more rational design.A través del análisis de la evolución de la deformación superficial observada experimentalmente en vigas de hormigón armado al entrar en carga, se constata que dicho proceso debe considerarse estocástico. En este trabajo se estudia la utilización de cadenas de Markov para modelizar la evolución estocástica de la deformación de vigas flexotraccionadas. Se propone, para establecer el estado de deformación de estas, un modelo con distribución gaussiana tipo cadena de Markov homogénea de dos niveles (BLHGMC por sus siglas en inglés, cuyo empleo resulta sencillo y práctico. Se comprueba la utilidad del modelo BLHGMC para prever el comportamiento de estos elementos, lo que determina a su vez una mayor racionalidad a la hora de su cálculo y diseño

  9. Markov state models of protein misfolding

    Science.gov (United States)

    Sirur, Anshul; De Sancho, David; Best, Robert B.

    2016-02-01

    Markov state models (MSMs) are an extremely useful tool for understanding the conformational dynamics of macromolecules and for analyzing MD simulations in a quantitative fashion. They have been extensively used for peptide and protein folding, for small molecule binding, and for the study of native ensemble dynamics. Here, we adapt the MSM methodology to gain insight into the dynamics of misfolded states. To overcome possible flaws in root-mean-square deviation (RMSD)-based metrics, we introduce a novel discretization approach, based on coarse-grained contact maps. In addition, we extend the MSM methodology to include "sink" states in order to account for the irreversibility (on simulation time scales) of processes like protein misfolding. We apply this method to analyze the mechanism of misfolding of tandem repeats of titin domains, and how it is influenced by confinement in a chaperonin-like cavity.

  10. Thermodynamic consistency of viscoplastic material models involving external variable rates in the evolution equations for the internal variables

    International Nuclear Information System (INIS)

    Malmberg, T.

    1993-09-01

    The objective of this study is to derive and investigate thermodynamic restrictions for a particular class of internal variable models. Their evolution equations consist of two contributions: the usual irreversible part, depending only on the present state, and a reversible but path dependent part, linear in the rates of the external variables (evolution equations of ''mixed type''). In the first instance the thermodynamic analysis is based on the classical Clausius-Duhem entropy inequality and the Coleman-Noll argument. The analysis is restricted to infinitesimal strains and rotations. The results are specialized and transferred to a general class of elastic-viscoplastic material models. Subsequently, they are applied to several viscoplastic models of ''mixed type'', proposed or discussed in the literature (Robinson et al., Krempl et al., Freed et al.), and it is shown that some of these models are thermodynamically inconsistent. The study is closed with the evaluation of the extended Clausius-Duhem entropy inequality (concept of Mueller) where the entropy flux is governed by an assumed constitutive equation in its own right; also the constraining balance equations are explicitly accounted for by the method of Lagrange multipliers (Liu's approach). This analysis is done for a viscoplastic material model with evolution equations of the ''mixed type''. It is shown that this approach is much more involved than the evaluation of the classical Clausius-Duhem entropy inequality with the Coleman-Noll argument. (orig.) [de

  11. Molecular recognition of the environment and mechanisms of the origin of species in quantum-like modeling of evolution.

    Science.gov (United States)

    Melkikh, Alexey V; Khrennikov, Andrei

    2017-11-01

    A review of the mechanisms of speciation is performed. The mechanisms of the evolution of species, taking into account the feedback of the state of the environment and mechanisms of the emergence of complexity, are considered. It is shown that these mechanisms, at the molecular level, cannot work steadily in terms of classical mechanics. Quantum mechanisms of changes in the genome, based on the long-range interaction potential between biologically important molecules, are proposed as one of possible explanation. Different variants of interactions of the organism and environment based on molecular recognition and leading to new species origins are considered. Experiments to verify the model are proposed. This bio-physical study is completed by the general operational model of based on quantum information theory. The latter is applied to model of epigenetic evolution. We briefly present the basics of the quantum-like approach to modeling of bio-informational processes. This approach is illustrated by the quantum-like model of epigenetic evolution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. EREM: Parameter Estimation and Ancestral Reconstruction by Expectation-Maximization Algorithm for a Probabilistic Model of Genomic Binary Characters Evolution

    Directory of Open Access Journals (Sweden)

    Liran Carmel

    2010-01-01

    Full Text Available Evolutionary binary characters are features of species or genes, indicating the absence (value zero or presence (value one of some property. Examples include eukaryotic gene architecture (the presence or absence of an intron in a particular locus, gene content, and morphological characters. In many studies, the acquisition of such binary characters is assumed to represent a rare evolutionary event, and consequently, their evolution is analyzed using various flavors of parsimony. However, when gain and loss of the character are not rare enough, a probabilistic analysis becomes essential. Here, we present a comprehensive probabilistic model to describe the evolution of binary characters on a bifurcating phylogenetic tree. A fast software tool, EREM, is provided, using maximum likelihood to estimate the parameters of the model and to reconstruct ancestral states (presence and absence in internal nodes and events (gain and loss events along branches.

  13. EREM: Parameter Estimation and Ancestral Reconstruction by Expectation-Maximization Algorithm for a Probabilistic Model of Genomic Binary Characters Evolution.

    Science.gov (United States)

    Carmel, Liran; Wolf, Yuri I; Rogozin, Igor B; Koonin, Eugene V

    2010-01-01

    Evolutionary binary characters are features of species or genes, indicating the absence (value zero) or presence (value one) of some property. Examples include eukaryotic gene architecture (the presence or absence of an intron in a particular locus), gene content, and morphological characters. In many studies, the acquisition of such binary characters is assumed to represent a rare evolutionary event, and consequently, their evolution is analyzed using various flavors of parsimony. However, when gain and loss of the character are not rare enough, a probabilistic analysis becomes essential. Here, we present a comprehensive probabilistic model to describe the evolution of binary characters on a bifurcating phylogenetic tree. A fast software tool, EREM, is provided, using maximum likelihood to estimate the parameters of the model and to reconstruct ancestral states (presence and absence in internal nodes) and events (gain and loss events along branches).

  14. Multimedia Mapping using Continuous State Space Models

    DEFF Research Database (Denmark)

    Lehn-Schiøler, Tue

    2004-01-01

    In this paper a system that transforms speech waveforms to animated faces are proposed. The system relies on continuous state space models to perform the mapping, this makes it possible to ensure video with no sudden jumps and allows continuous control of the parameters in 'face space'. Simulations...... are performed on recordings of 3-5 sec. video sequences with sentences from the Timit database. The model is able to construct an image sequence from an unknown noisy speech sequence fairly well even though the number of training examples are limited....

  15. A Triaxial Characteristic State Model for Sand

    DEFF Research Database (Denmark)

    Krenk, S.; Borup, M.; Hedegaard, J.

    the loading surfaces approach the zero-tension planes asymptotically, generating a nearly triangular contour in the deviator ic stress plane. The gradient of the flow potential is generated directly from the gradient of the loading potential by scaling of the mean stress component. Two hardening rules...... that permit ultimate stress states beyond the characteristic line have been proposed. Results from drained triaxial tests show good agreement with the model, usi ng a weighted work hardening rule....

  16. Fitting models of continuous trait evolution to incompletely sampled comparative data using approximate Bayesian computation.

    Science.gov (United States)

    Slater, Graham J; Harmon, Luke J; Wegmann, Daniel; Joyce, Paul; Revell, Liam J; Alfaro, Michael E

    2012-03-01

    In recent years, a suite of methods has been developed to fit multiple rate models to phylogenetic comparative data. However, most methods have limited utility at broad phylogenetic scales because they typically require complete sampling of both the tree and the associated phenotypic data. Here, we develop and implement a new, tree-based method called MECCA (Modeling Evolution of Continuous Characters using ABC) that uses a hybrid likelihood/approximate Bayesian computation (ABC)-Markov-Chain Monte Carlo approach to simultaneously infer rates of diversification and trait evolution from incompletely sampled phylogenies and trait data. We demonstrate via simulation that MECCA has considerable power to choose among single versus multiple evolutionary rate models, and thus can be used to test hypotheses about changes in the rate of trait evolution across an incomplete tree of life. We finally apply MECCA to an empirical example of body size evolution in carnivores, and show that there is no evidence for an elevated rate of body size evolution in the pinnipeds relative to terrestrial carnivores. ABC approaches can provide a useful alternative set of tools for future macroevolutionary studies where likelihood-dependent approaches are lacking. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

  17. Modeling evolution of crosstalk in noisy signal transduction networks

    Science.gov (United States)

    Tareen, Ammar; Wingreen, Ned S.; Mukhopadhyay, Ranjan

    2018-02-01

    Signal transduction networks can form highly interconnected systems within cells due to crosstalk between constituent pathways. To better understand the evolutionary design principles underlying such networks, we study the evolution of crosstalk for two parallel signaling pathways that arise via gene duplication. We use a sequence-based evolutionary algorithm and evolve the network based on two physically motivated fitness functions related to information transmission. We find that one fitness function leads to a high degree of crosstalk while the other leads to pathway specificity. Our results offer insights on the relationship between network architecture and information transmission for noisy biomolecular networks.

  18. Magnetic field of Mercury and models of thermal evolution

    International Nuclear Information System (INIS)

    Sharpe, H.N.; Strangway, D.W.

    1976-01-01

    Recent planetary probes have performed in situ measurements of the magnetic fields of all the terrestrial planets. Consideration is given to the origin of these fields, with attention to the equilibrium-- condensation hypothesis for the formation of the solar system. In particular, it is shown that Mercury's present day magnetic field could have been acquired during or shortly after a cold accretion or that it could be due to a presently operating dynamo, resulting from a 'hot evolution'. Two parameters which would help to distinguish between these possibilities are the present-day surface heat flow and the moment of inertia

  19. LONG-TERM EVOLUTION OF THE MAIN-ON STATES IN HERCULES X-1

    Energy Technology Data Exchange (ETDEWEB)

    Šimon, Vojtech, E-mail: simon@asu.cas.cz [Astronomical Institute, The Czech Academy of Sciences, 25165 Ondřejov (Czech Republic)

    2015-07-15

    Rossi X-ray Timing Explorer All-sky Monitor (RXTE ASM) observations and American Association of Variable Star Observers (AAVSO) optical data were used for a time-series analysis of the long-term activity of Her X-1. The problem of measuring the long-term evolution of the X-ray intensity in the light curve which consists only of separated intense spikes was addressed. For this purpose, the fluence of each Main-On state was determined. The fluences vary generally (not only in the transitions into/from anomalous low states (ALSs)) by tens of percent on timescales of at least several epochs of the cycle length of the superorbital cycle (but without any stable cycle) while irradiation of the donor producing the optical modulation remains considerably more stable. ALS1 and ALS2 are extensions of the tail in the statistical distribution of these fluences. In this interpretation, the variations of the fluences are caused by the changes of the structure of the inner disk region, which produces variable obscuration of the beams (emitting in the ASM band) at the neutron star. A small change of obscuration of these beams by the inner disk region suffices to change the fluences largely. However, the irradiation of the donor is changed significantly less because this inner disk region (which emits beyond the ASM band and acts as the occulting region of the beams) also irradiates the donor.

  20. Lighting the Path: the Evolution of the Islamic State Media Enterprise (2003-2016

    Directory of Open Access Journals (Sweden)

    Craig Whiteside

    2016-11-01

    Full Text Available The media products of the revolutionary movement known as the Islamic State (also IS, ISIL, ISIS, Daesh have received a significant amount of attention from analysts and journalists alike. While extremely helpful, most of this effort is focused at performing content analysis of fairly recent products. As part of the Counter-Terrorism Strategic Communication (CTSC project’s effort to better understand propaganda messaging in the 21st century, the author of this Research Paper examined primary documents and other media published by the Islamic State movement during its entire existence in order to develop a history of the media department since 2003. The framework for analysis focused on the interaction between key media leaders, the ever-expanding structure and institutions, and the process of innovation used to experiment with different media techniques in different phases of the group’s evolution. Based on this history, the paper presents six observations about the media department and its role in the larger movement – in the hopes that this knowledge will be helpful in efforts to combat this particular group and its inevitable imitators in the future.

  1. Local evolution of pyrethroid resistance offsets gene flow among Aedes aegypti collections in Yucatan State, Mexico.

    Science.gov (United States)

    Saavedra-Rodriguez, Karla; Beaty, Meaghan; Lozano-Fuentes, Saul; Denham, Steven; Garcia-Rejon, Julian; Reyes-Solis, Guadalupe; Machain-Williams, Carlos; Loroño-Pino, Maria Alba; Flores-Suarez, Adriana; Ponce-Garcia, Gustavo; Beaty, Barry; Eisen, Lars; Black, William C

    2015-01-01

    The mosquito Aedes aegypti is the major vector of the four serotypes of dengue virus (DENV1-4). Previous studies have shown that Ae. aegypti in Mexico have a high effective migration rate and that gene flow occurs among populations that are up to 150 km apart. Since 2000, pyrethroids have been widely used for suppression of Ae. aegypti in cities in Mexico. In Yucatan State in particular, pyrethroids have been applied in and around dengue case households creating an opportunity for local selection and evolution of resistance. Herein, we test for evidence of local adaptation by comparing patterns of variation among 27 Ae. aegypti collections at 13 single nucleotide polymorphisms (SNPs): two in the voltage-gated sodium channel gene para known to confer knockdown resistance, three in detoxification genes previously associated with pyrethroid resistance, and eight in putatively neutral loci. The SNPs in para varied greatly in frequency among collections, whereas SNPs at the remaining 11 loci showed little variation supporting previous evidence for extensive local gene flow. Among Ae. aegypti in Yucatan State, Mexico, local adaptation to pyrethroids appears to offset the homogenizing effects of gene flow. © The American Society of Tropical Medicine and Hygiene.

  2. Testing gradual and speciational models of evolution in extant taxa: the example of ratites

    NARCIS (Netherlands)

    Laurin, M.; Gussekloo, S.W.S.; Marjanovic, D.; Legendre, L.; Cubo, J.

    2012-01-01

    Ever since Eldredge and Gould proposed their model of punctuated equilibria, evolutionary biologists have debated how often this model is the best description of nature and how important it is compared to the more gradual models of evolution expected from natural selection and the neo-Darwinian

  3. Physical model of evolution of oxygen subsystem of PLZT-ceramics at neutron irradiation and annealing

    CERN Document Server

    Kulikov, D V; Trushin, Y V; Veber, K V; Khumer, K; Bitner, R; Shternberg, A R

    2001-01-01

    The physical model of evolution of the oxygen subsystem defects of the ferroelectric PLZT-ceramics by the neutron irradiation and isochrone annealing is proposed. The model accounts for the effect the lanthanum content on the material properties. The changes in the oxygen vacancies concentration, calculated by the proposed model, agree well with the polarization experimental behavior by the irradiated material annealing

  4. Gene finding with a hidden Markov model of genome structure and evolution

    DEFF Research Database (Denmark)

    Pedersen, Jakob Skou; Hein, Jotun

    2003-01-01

    the model are linear in alignment length and genome number. The model is applied to the problem of gene finding. The benefit of modelling sequence evolution is demonstrated both in a range of simulations and on a set of orthologous human/mouse gene pairs. AVAILABILITY: Free availability over the Internet...

  5. Recent topographic evolution and erosion of the deglaciated Washington Cascades inferred from a stochastic landscape evolution model

    Science.gov (United States)

    Moon, Seulgi; Shelef, Eitan; Hilley, George E.

    2015-05-01

    In this study, we model postglacial surface processes and examine the evolution of the topography and denudation rates within the deglaciated Washington Cascades to understand the controls on and time scales of landscape response to changes in the surface process regime after deglaciation. The postglacial adjustment of this landscape is modeled using a geomorphic-transport-law-based numerical model that includes processes of river incision, hillslope diffusion, and stochastic landslides. The surface lowering due to landslides is parameterized using a physically based slope stability model coupled to a stochastic model of the generation of landslides. The model parameters of river incision and stochastic landslides are calibrated based on the rates and distribution of thousand-year-time scale denudation rates measured from cosmogenic 10Be isotopes. The probability distributions of those model parameters calculated based on a Bayesian inversion scheme show comparable ranges from previous studies in similar rock types and climatic conditions. The magnitude of landslide denudation rates is determined by failure density (similar to landslide frequency), whereas precipitation and slopes affect the spatial variation in landslide denudation rates. Simulation results show that postglacial denudation rates decay over time and take longer than 100 kyr to reach time-invariant rates. Over time, the landslides in the model consume the steep slopes characteristic of deglaciated landscapes. This response time scale is on the order of or longer than glacial/interglacial cycles, suggesting that frequent climatic perturbations during the Quaternary may produce a significant and prolonged impact on denudation and topography.

  6. Multi-process Late Quaternary landscape evolution modelling reveals lags in climate response over small spatial scales

    NARCIS (Netherlands)

    Temme, A.J.A.M.; Veldkamp, A.

    2009-01-01

    Landscapes evolve in complex, non-linear ways over Quaternary timespans. Integrated geomorphological field studies usually yield plausible hypotheses about timing and impact of process activity. Landscape Evolution Models (LEMs) have the potential to test and falsify these landscape evolution

  7. Modeled alongshore circulation and morphologic evolution onshore of a large submarine canyon

    Science.gov (United States)

    Hansen, J. E.; Raubenheimer, B.; List, J. H.; Elgar, S.; Guza, R. T.; Lippmann, T. C.

    2012-12-01

    Alongshore circulation and morphologic evolution observed at an ocean beach during the Nearshore Canyon Experiment, onshore of a large submarine canyon in San Diego, CA (USA), are investigated using a two-dimensional depth-averaged numerical model (Delft3D). The model is forced with waves observed in ~500 m water depth and tidal constituents derived from satellite altimetry. Consistent with field observations, the model indicates that refraction of waves over the canyon results in wave focusing ~500 m upcoast of the canyon and shadowing onshore of the canyon. The spatial variability in the modeled wave field results in a corresponding non-uniform alongshore circulation field. In particular, when waves approach from the northwest the alongshore flow converges near the wave focal zone, while waves that approach from the southwest result in alongshore flow that diverges away from the wave focal zone. The direction and magnitude of alongshore flows are determined by a balance between the (often opposing) radiation stress and alongshore pressure gradients, consistent with observations and previous results. The largest observed morphologic evolution, vertical accretion of about 1.5 m in about 3 m water depth near the wave focal zone, occurred over a one-week period when waves from the northwest reached heights of 1.8 m. The model, with limited tuning, replicates the magnitude and spatial extent of the observed accretion and indicates that net accretion of the cross-shore profile was owing to alongshore transport from converging alongshore flows. The good agreement between the observed and modeled morphology change allows for an in-depth examination of the alongshore force balance that resulted in the sediment convergence. These results indicate that, at least in this case, a depth-averaged hydrodynamic model can replicate observed surfzone morphologic change resulting from forcing that is strongly non-uniform in the alongshore. Funding was provided by the Office of Naval

  8. Trans gene regulation in adaptive evolution: a genetic algorithm model.

    Science.gov (United States)

    Behera, N; Nanjundiah, V

    1997-09-21

    This is a continuation of earlier studies on the evolution of infinite populations of haploid genotypes within a genetic algorithm framework. We had previously explored the evolutionary consequences of the existence of indeterminate-"plastic"-loci, where a plastic locus had a finite probability in each generation of functioning (being switched "on") or not functioning (being switched "off"). The relative probabilities of the two outcomes were assigned on a stochastic basis. The present paper examines what happens when the transition probabilities are biased by the presence of regulatory genes. We find that under certain conditions regulatory genes can improve the adaptation of the population and speed up the rate of evolution (on occasion at the cost of lowering the degree of adaptation). Also, the existence of regulatory loci potentiates selection in favour of plasticity. There is a synergistic effect of regulatory genes on plastic alleles: the frequency of such alleles increases when regulatory loci are present. Thus, phenotypic selection alone can be a potentiating factor in a favour of better adaptation. Copyright 1997 Academic Press Limited.

  9. State governance evolution in resource-rich transition economies: An application to Russia and Kazakhstan

    Energy Technology Data Exchange (ETDEWEB)

    Kalyuzhnova, Yelena; Nygaard, Christian [The Centre for Euro-Asian Studies, The University of Reading, Whiteknights, PO Box, Reading RG6 6AA (United Kingdom)

    2008-06-15

    Following a decade of transition in the Former Soviet Union (FSU), governance of the oil and gas sectors has evolved to economic nationalism. In the newly independent states this has manifested itself through greater (direct) state ownership or participation in oil and gas production, at the expense of both domestic (in the case of Russia) and international oil companies, as well as legislative developments that increase the flow of oil and gas value to the state. Here we analyse some of the dynamics giving rise to economic nationalism within a model of a state capacity and the ability to implement policy and extract value. Our analysis is based on the institutional and economic functioning of the oil and gas sector. We analyse a vector of institutions and examine Production Sharing Agreements and National Oil Companies. (author)

  10. Development of a state machine sequencer for the Keck Interferometer: evolution, development, and lessons learned using a CASE tool approach

    Science.gov (United States)

    Reder, Leonard J.; Booth, Andrew; Hsieh, Jonathan; Summers, Kellee R.

    2004-09-01

    This paper presents a discussion of the evolution of a sequencer from a simple Experimental Physics and Industrial Control System (EPICS) based sequencer into a complex implementation designed utilizing UML (Unified Modeling Language) methodologies and a Computer Aided Software Engineering (CASE) tool approach. The main purpose of the Interferometer Sequencer (called the IF Sequencer) is to provide overall control of the Keck Interferometer to enable science operations to be carried out by a single operator (and/or observer). The interferometer links the two 10m telescopes of the W. M. Keck Observatory at Mauna Kea, Hawaii. The IF Sequencer is a high-level, multi-threaded, Harel finite state machine software program designed to orchestrate several lower-level hardware and software hard real-time subsystems that must perform their work in a specific and sequential order. The sequencing need not be done in hard real-time. Each state machine thread commands either a high-speed real-time multiple mode embedded controller via CORBA, or slower controllers via EPICS Channel Access interfaces. The overall operation of the system is simplified by the automation. The UML is discussed and our use of it to implement the sequencer is presented. The decision to use the Rhapsody product as our CASE tool is explained and reflected upon. Most importantly, a section on lessons learned is presented and the difficulty of integrating CASE tool automatically generated C++ code into a large control system consisting of multiple infrastructures is presented.

  11. Evolution of Air Quality Model at the US EPA

    Science.gov (United States)

    At the US EPA, we have developed an air quality model, CMAQ, in the past 20+ years. Throughout the years, the model has been upgraded with respect to advancement of science. We have extended the model from regional to hemispheric. We have coupled it with meteorological model, WR...

  12. Parameter and State Estimator for State Space Models

    Directory of Open Access Journals (Sweden)

    Ruifeng Ding

    2014-01-01

    Full Text Available This paper proposes a parameter and state estimator for canonical state space systems from measured input-output data. The key is to solve the system state from the state equation and to substitute it into the output equation, eliminating the state variables, and the resulting equation contains only the system inputs and outputs, and to derive a least squares parameter identification algorithm. Furthermore, the system states are computed from the estimated parameters and the input-output data. Convergence analysis using the martingale convergence theorem indicates that the parameter estimates converge to their true values. Finally, an illustrative example is provided to show that the proposed algorithm is effective.

  13. High Spatial Resolution of Atmospheric Particle Mixing State and Its Links to Particle Evolution in a Metropolitan Area

    Science.gov (United States)

    Ye, Q.; Gu, P.; Li, H.; Robinson, E. S.; Apte, J.; Sullivan, R. C.; Robinson, A. L.; Presto, A. A.; Donahue, N.

    2017-12-01

    Traditional air quality studies in urban areas have mostly relied on very few monitoring locations either at urban background sites or at roadside sites.However, air pollution is highly complex and dynamic and will undergo complicated transformations. Therefore, results from one or two monitoring sites may not be sufficient to address the spatial gradients of pollutants and their evolution after atmosphere processing on a local scale. Our study, as part of the Center for Air, Climate, and Energy Solutions, performed stratified mobile sampling of atmospheric particulate matter with high spatial resolution to address intra-city variability of atmospheric particle composition and mixing state. A suite of comprehensive real-time instrumentations including a state-of-the-art aerosol mass spectrometer with single particle measurement capability are deployed on the mobile platform. Our sampling locations covered a wide variety of places with substantial differences in emissions and land use types including tunnels, inter-state highways, commercial areas, residential neighborhood, parks, as well as locations upwind and downwind of the city center. Our results show that particles from traffic emissions and restaurant cookings are two major contributors to fresh particles in the urban environment. In addition, there are large spatial variabilities of source-specific particles and we identify the relevant physicochemical processes governing transformation of particle composition, size and mixing state. We also combine our results with demographic data to study population exposure to particles of specific sources. This work will help evaluate the performance of existing modeling tools for air quality and population exposure studies.

  14. Multivariable Wind Modeling in State Space

    DEFF Research Database (Denmark)

    Sichani, Mahdi Teimouri; Pedersen, B. J.

    2011-01-01

    Turbulence of the incoming wind field is of paramount importance to the dynamic response of wind turbines. Hence reliable stochastic models of the turbulence should be available from which time series can be generated for dynamic response and structural safety analysis. In the paper an empirical...... for the vector turbulence process incorporating its phase spectrum in one stage, and its results are compared with a conventional ARMA modeling method....... the succeeding state space and ARMA modeling of the turbulence rely on the positive definiteness of the cross-spectral density matrix, the problem with the non-positive definiteness of such matrices is at first addressed and suitable treatments regarding it are proposed. From the adjusted positive definite cross...

  15. A model for the description of the evolution of PU agglomerates in MOX fuels

    Energy Technology Data Exchange (ETDEWEB)

    Federici, E [CEA Centre d` Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France); Blanpain, P [FRAMATOME, Lyon (France); Permezel, P [Electricite de France, Moret-sur-Loing (France)

    1997-08-01

    In order to describe the irradiation behavior of Pu agglomerates under LWR steady state conditions in MIMAS MOX fuels, a model including the neutronic evolution of the heavy atoms and their diffusion processes between the agglomerates and the matrix has been developed. It leads to the calculations of Pu enrichment in the two phases and of the agglomerates size evolution during irradiation. The calculated distribution of the fission in the fuel gives access to the local power and burnup heterogeneity factor. Electron probe microanalyses (EPMA) have been carried out on fuels irradiated up to 45000 MWd/tM. Diametral and local distribution of Pu are used to calculate the enrichments of the agglomerates and the matrix, which are then compared to the results of the model. During irradiation, the Pu concentration falls markedly in the agglomerates and increases steadily in the matrix, leading to a homogenization of the fuel on a microstructural scale. Heterogeneity factors give an estimate of the deviation from homogeneity. Knowing the local fission rate and burnup in the agglomerates and the matrix enables the calculation of the local fission gas concentrations, which are compared to the xenon EPMA diametral distribution. Comparison with the calculated matrix xenon concentration at the edge of the pellet where there is no gas release, shows that some fission gas atoms which originated from the agglomerates, have been dissolved in the matrix by recoil. The calculated gas concentrations give an estimate of the quantity of gas dissolved. This work has been performed with the intent to improved fuel rod performance code estimates of fission gas concentrations retained or released in both the matrix and the agglomerates. (author). 4 refs, 7 figs.

  16. A model for the description of the evolution of PU agglomerates in MOX fuels

    International Nuclear Information System (INIS)

    Federici, E.; Blanpain, P.; Permezel, P.

    1997-01-01

    In order to describe the irradiation behavior of Pu agglomerates under LWR steady state conditions in MIMAS MOX fuels, a model including the neutronic evolution of the heavy atoms and their diffusion processes between the agglomerates and the matrix has been developed. It leads to the calculations of Pu enrichment in the two phases and of the agglomerates size evolution during irradiation. The calculated distribution of the fission in the fuel gives access to the local power and burnup heterogeneity factor. Electron probe microanalyses (EPMA) have been carried out on fuels irradiated up to 45000 MWd/tM. Diametral and local distribution of Pu are used to calculate the enrichments of the agglomerates and the matrix, which are then compared to the results of the model. During irradiation, the Pu concentration falls markedly in the agglomerates and increases steadily in the matrix, leading to a homogenization of the fuel on a microstructural scale. Heterogeneity factors give an estimate of the deviation from homogeneity. Knowing the local fission rate and burnup in the agglomerates and the matrix enables the calculation of the local fission gas concentrations, which are compared to the xenon EPMA diametral distribution. Comparison with the calculated matrix xenon concentration at the edge of the pellet where there is no gas release, shows that some fission gas atoms which originated from the agglomerates, have been dissolved in the matrix by recoil. The calculated gas concentrations give an estimate of the quantity of gas dissolved. This work has been performed with the intent to improved fuel rod performance code estimates of fission gas concentrations retained or released in both the matrix and the agglomerates. (author). 4 refs, 7 figs

  17. Cosmological evolution as squeezing: a toy model for group field cosmology

    Science.gov (United States)

    Adjei, Eugene; Gielen, Steffen; Wieland, Wolfgang

    2018-05-01

    We present a simple model of quantum cosmology based on the group field theory (GFT) approach to quantum gravity. The model is formulated on a subspace of the GFT Fock space for the quanta of geometry, with a fixed volume per quantum. In this Hilbert space, cosmological expansion corresponds to the generation of new quanta. Our main insight is that the evolution of a flat Friedmann–Lemaître–Robertson–Walker universe with a massless scalar field can be described on this Hilbert space as squeezing, familiar from quantum optics. As in GFT cosmology, we find that the three-volume satisfies an effective Friedmann equation similar to the one of loop quantum cosmology, connecting the classical contracting and expanding solutions by a quantum bounce. The only free parameter in the model is identified with Newton’s constant. We also comment on the possible topological interpretation of our squeezed states. This paper can serve as an introduction into the main ideas of GFT cosmology without requiring the full GFT formalism; our results can also motivate new developments in GFT and its cosmological application.

  18. Models for light QCD bound states

    International Nuclear Information System (INIS)

    LaCourse, D.P.

    1992-01-01

    After a brief overview of Regge, tower, and heavy-quark experimental data, this thesis examines two massless wave equations relevant to quark bound states. We establish general conditions on the Lorentz scalar and Lorentz vector potentials which yield arbitrary leading Regge trajectories for the case of circular classical motion. A semi-classical approximation which includes radial motion reproduces remarkably well the exact solutions. Conditions for tower structure are examined, and found to be incompatible with conditions which give a Nambu stringlike Regge slope. The author then proposes a generalization of the usual potential model of quark bound states in which the confining flux tube is a dynamical object carrying both angular momentum and energy. The Q bar Q-string system with spinless quarks is quantized using an implicit operator technique and the resulting relativistic wave equation is solved. For heavy quarks the usual Schroedinger valence-quark model is recovered. The Regge slope with light quarks agree with the classical rotating-string result and is significantly larger and the effects of short-range forces are also considered. A relativistic generalization of the quantized flux tube model predicts the glueball ground state mass to be √3/α' ≅ 1.9 GeV where α' is the normal Regge slope. The groundstate as well as excited levels like considerably above the expectations of previous models and also above various proposed experimental candidates. The glueball Regge slope is only about three-eighths that for valence quark hadrons. A semi-classical calculation of the Regge slope is in good agreement with a numerically exact value

  19. The Analysis of the Evolution of Tax Revenues in EU Member States during 2009-2013

    Directory of Open Access Journals (Sweden)

    Cornelia Elena Tureac

    2014-10-01

    Full Text Available The state budget is a financial plan at the macroeconomic level, and it is designed as a set of accounts of the nation, which reflects the current year and next year projections on all economic agents in the country / region. The size of the public sector varies significantly from one Member State to another, which means that the financial resources available to the public sector differ substantially at the European Union level. The paper includes an analysis of the evolution of the main indicators corresponding to public financial resources at EU level achieved between January 2009 - December 2012 or December 2013, where data processing was available. The information was taken from the Eurostat statistics database. The research methodology used in this work was done by the use of indicators: the share of total public revenue in GDP; the share of taxes in GDP of production and imports; the share of current taxes on income, wealth etc. in GDP; the share of social security contributions in GDP. In the analysis there were considered, of the total financial resources of government, only the taxes levied on production and imports, current taxes on income, wealth etc. and social security contributions. In conclusion, the share of government revenues in GDP increases, but there are states where it decreases, such as Estonia, Lithuania, Luxembourg, Germany and Sweden. The public financial resources share in GDP at the level of the Eurozone was always higher in relation to the entire European Union, but always keeping the difference around 0.8 to 0.9 percentage points. France recorded the highest share of social security contributions in GDP (18.8% in 2009 and 19.4% in 2013 while Denmark has the lowest share of these financial resources in GDP, i.e. only 1.9% in 2009 and 1.8% in 2013.

  20. A three states sleep-waking model

    International Nuclear Information System (INIS)

    Comte, J.C.; Schatzman, M.; Ravassard, P.; Luppi, P.H.; Salin, P.A.

    2006-01-01

    The mechanisms underlying the sleep-states periodicity in animals are a mystery of biology. Recent studies identified a new neuronal population activated during the slow wave sleep (SWS) in the ventral lateral preoptic area of the hypothalamus. Interactions between this neuronal population and the others populations implicated in the vigilance states (paradoxical sleep (PS) and wake (W)) dynamics are not determined. Thus, we propose here a sleep-waking theoretical model that depicts the potential interactions between the neuronal populations responsible for the three vigilance states. First, we pooled data from previous papers regarding the neuronal populations firing rate time course and characterized statistically the experimental hypnograms. Then, we constructed a nonlinear differential equations system describing the neuronal populations activity time course. A simple rule playing the firing threshold role applied to the model allows to construct a theoretical hypnogram. A random modulation of the neuronal activity, shows that theoretical hypnograms present a dynamics close to the experimental observations. Furthermore, we show that the wake promoting neurons activity can predict the next SWS episode duration

  1. Phase-field model and its numerical solution for coring and microstructure evolution studies in alloys

    Science.gov (United States)

    Turchi, Patrice E. A.; Fattebert, Jean-Luc; Dorr, Milo R.; Wickett, Michael E.; Belak, James F.

    2011-03-01

    We describe an algorithm for the numerical solution of a phase-field model (PFM) of microstructure evolution in alloys using physical parameters from thermodynamic (CALPHAD) and kinetic databases. The coupled system of PFM equations includes a local order parameter, a quaternion representation of local crystal orientation and a species composition parameter. Time evolution of microstructures and alloy composition is obtained using an implicit time integration of the system. Physical parameters in databases can be obtained either through experiment or first-principles calculations. Application to coring studies and microstructure evolution of Au-Ni will be presented. Prepared by LLNL under Contract DE-AC52-07NA27344

  2. Dynamic modelling of hydrogen evolution effects in the all-vanadium redox flow battery

    International Nuclear Information System (INIS)

    Shah, A.A.; Al-Fetlawi, H.; Walsh, F.C.

    2010-01-01

    A model for hydrogen evolution in an all-vanadium redox flow battery is developed, coupling the dynamic conservation equations for charge, mass and momentum with a detailed description of the electrochemical reactions. Bubble formation at the negative electrode is included in the model, taking into account the attendant reduction in the liquid volume and the transfer of momentum between the gas and liquid phases, using a modified multiphase-mixture approach. Numerical simulations are compared to experimental data for different vanadium concentrations and mean linear electrolyte flow rates, demonstrating good agreement. Comparisons to simulations with negligible hydrogen evolution demonstrate the effect of gas evolution on the efficiency of the battery. The effects of reactant concentration, flow rate, applied current density and gas bubble diameter on hydrogen evolution are investigated. Significant variations in the gas volume fraction and the bubble velocity are predicted, depending on the operating conditions.

  3. Lifetime measurements of the first 2+ states in 104,106Zr: Evolution of ground-state deformations

    Directory of Open Access Journals (Sweden)

    F. Browne

    2015-11-01

    Full Text Available The first fast-timing measurements from nuclides produced via the in-flight fission mechanism are reported. The lifetimes of the first 2+ states in 104,106Zr nuclei have been measured via β-delayed γ-ray timing of stopped radioactive isotope beams. An improved precision for the lifetime of the 21+ state in 104Zr was obtained, τ(21+=2.90−20+25 ns, as well as a first measurement of the 21+ state in 106Zr, τ(21+=2.60−15+20 ns, with corresponding reduced transition probabilities of B(E2;21+→0g.s.+=0.39(2 e2b2 and 0.31(1 e2b2, respectively. Comparisons of the extracted ground-state deformations, β2=0.39(1 (104Zr and β2=0.36(1 (106Zr with model calculations indicate a persistence of prolate deformation. The data show that 104Zr is the most deformed of the neutron-rich Zr isotopes measured so far.

  4. Geochemical modelling of groundwater evolution and residence time at the Kivetty site

    Energy Technology Data Exchange (ETDEWEB)

    Pitkaenen, P.; Luukkonen, A. [VTT Communities and Infrastructure, Espoo (Finland); Ruotsalainen, P. [Fintact Oy, Helsinki (Finland); Leino-Forsman, H.; Vuorinen, U. [VTT Chemical Technology, Espoo (Finland)

    1998-12-01

    An understanding of the geochemical evolution of groundwater is an essential part of the performance assessment and safety analysis of the final disposal of radioactive waste into the bedrock. The performance of technical barriers and migration of possibly released radionuclides depend on chemical conditions. A prerequisite for understanding these factors is the ability to specify the water-rock interactions which control chemical conditions in groundwater. The objective of this study is to interpret the processes and factors which control the hydrogeochemistry, such as pH and redox conditions. A model of the hydrogeochemical progress in different parts of the bedrock at Kivetty has been created and the significance of chemical reactions along different flowpaths calculated. Long term hydrodynamics have also been evaluated. The interpretation and modelling are based on groundwater samples (38 altogether) obtained from the soil layer, shallow wells in the bedrock, and five deep multi-packered boreholes (KRI-KR5) in the bedrock for which a comprehensive data set on dissolved chemical species and isotopes was available. Some analyses of dissolved gases and their isotopic measurements were also utilised. The data covers the bedrock at Kivetty to a depth of 850m. The results from groundwater chemistry, isotopes, petrography, hydrogeology of the site, geomicrobial studies, and PCA and speciation calculations were used in the evaluation of evolutionary processes at the site. The geochemical interpretation of water-rock interaction, isotope-chemical evolution and C-14 age calculations of groundwater was given a mass-balance approach (NETPATH). Reaction-path calculations (EQ3/6) were used to verify the thermodynamic feasibility of the reaction models obtained. The hydrogeochemistry of Kivetty is characterised by evolution from low-saline-carbonate-rich recharge water towards Na-Ca-Cl-type water. The salinity remains low. The most important changes in the chemistry of the

  5. Geochemical modelling of groundwater evolution and residence time at the Kivetty site

    International Nuclear Information System (INIS)

    Pitkaenen, P.; Luukkonen, A.; Ruotsalainen, P.; Leino-Forsman, H.; Vuorinen, U.

    1998-12-01

    An understanding of the geochemical evolution of groundwater is an essential part of the performance assessment and safety analysis of the final disposal of radioactive waste into the bedrock. The performance of technical barriers and migration of possibly released radionuclides depend on chemical conditions. A prerequisite for understanding these factors is the ability to specify the water-rock interactions which control chemical conditions in groundwater. The objective of this study is to interpret the processes and factors which control the hydrogeochemistry, such as pH and redox conditions. A model of the hydrogeochemical progress in different parts of the bedrock at Kivetty has been created and the significance of chemical reactions along different flowpaths calculated. Long term hydrodynamics have also been evaluated. The interpretation and modelling are based on groundwater samples (38 altogether) obtained from the soil layer, shallow wells in the bedrock, and five deep multi-packered boreholes (KRI-KR5) in the bedrock for which a comprehensive data set on dissolved chemical species and isotopes was available. Some analyses of dissolved gases and their isotopic measurements were also utilised. The data covers the bedrock at Kivetty to a depth of 850m. The results from groundwater chemistry, isotopes, petrography, hydrogeology of the site, geomicrobial studies, and PCA and speciation calculations were used in the evaluation of evolutionary processes at the site. The geochemical interpretation of water-rock interaction, isotope-chemical evolution and C-14 age calculations of groundwater was given a mass-balance approach (NETPATH). Reaction-path calculations (EQ3/6) were used to verify the thermodynamic feasibility of the reaction models obtained. The hydrogeochemistry of Kivetty is characterised by evolution from low-saline-carbonate-rich recharge water towards Na-Ca-Cl-type water. The salinity remains low. The most important changes in the chemistry of the

  6. Modeling Protoplanetary Disks to Characterize the Evolution of their Structure

    Science.gov (United States)

    Allen, Magdelena; van der Marel, Nienke; Williams, Jonathan

    2018-01-01

    Stars form from gravitationally collapsing clouds of gas and dust. Most young stars retain a protoplanetary disk for a few million years. This disk’s dust reemits stellar flux in the infrared, producing a spectral energy distribution (SED) observable by Spitzer and other telescopes. To understand the inner clearing of dust cavities and evolution in the SED, we used the Chiang & Goldreich two-layer approximation. We first wrote a python script based on refinements by Dullemond that includes a hot, puffed inner rim, shadowed mid region, flaring outer disk, and a variable inner cavity. This was then coupled with a Markov Chain Monte Carlo procedure to fit the observed SEDs of disks in the star forming Lupus region. The fitting procedure recovers physical characteristics of the disk including temperature, size, mass, and surface density. We compare the characteristics of circumstellar disks without holes and more evolved transition disks with cleared inner regions.

  7. A new surface-process model for landscape evolution at a mountain belt scale

    Science.gov (United States)

    Willett, Sean D.; Braun, Jean; Herman, Frederic

    2010-05-01

    We present a new surface process model designed for modeling surface erosion and mass transport at an orogenic scale. Modeling surface processes at a large-scale is difficult because surface geomorphic processes are frequently described at the scale of a few meters, and such resolution cannot be represented in orogen-scale models operating over hundreds of square kilometers. We circumvent this problem by implementing a hybrid numerical -- analytical model. Like many previous models, the model is based on a numerical fluvial network represented by a series of nodes linked by model rivers in a descending network, with fluvial incision and sediment transport defined by laws operating on this network. However we only represent the largest rivers in the landscape by nodes in this model. Low-order rivers and water divides between large rivers are determined from analytical solutions assuming steady-state conditions with respect to the local river channel. The analytical solution includes the same fluvial incision law as the large rivers and a channel head with a specified size and mean slope. This permits a precise representation of the position of water divides between river basins. This is a key characteristic in landscape evolution as divide migration provides a positive feedback between river incision and a consequent increase in drainage area. The analytical solution also provides an explicit criterion for river capture, which occurs once a water divide migrates to its neighboring channel. This algorithm avoids the artificial network organization that often results from meshing and remeshing algorithms in numerical models. We demonstrate the use of this model with several simple examples including uniform uplift of a block, simultaneous uplift and shortening of a block, and a model involving strike slip faulting. We find a strong dependence on initial condition, but also a surprisingly strong dependence on channel head height parameters. Low channel heads, as

  8. The influence of international and domestic events in the evolution of forest inventory and reporting consistency in the United States

    Science.gov (United States)

    W. Brad Smith

    2009-01-01

    This article takes a brief chronological look at resource inventory and reporting and links to international influences. It explores events as drivers of more consistent data within the United States and highlights key dates and events in the evolution of inventory policy and practice. From King George to L?Ecole nationale forestiere to the Food and Agriculture...

  9. Origin and evolution of the Pirituba aluminous calc-alkalic magma, state of Sao Paulo, SE Brazil

    International Nuclear Information System (INIS)

    Wernick, Eberhard

    1999-01-01

    The origin and evolution of the Late Proterozoic calc-alkalic Pirituba magmatism near the city of Sao Paulo, State of Sao Paulo, SE Brazil, are presented and discussed on the basis of geological, petrographic, mineralogical, chemical (rocks and minerals), isotopic and zircon typology data. (author)

  10. Cooperative Office Education: Its Evolution in the Secondary Schools of the United States from 1900-1969.

    Science.gov (United States)

    Donley, Audrey Bell

    Using the historical, documentary analysis, and questionnaire methods of research, this study traces the development and evolution of cooperative office education in the secondary schools of the United States from 1900 through 1969. The study was organized under the following topical divisions: (1) Original of Vocational Education, (2) Development…

  11. Damage evolution under cyclic multiaxial stress state: A comparative analysis between glass/epoxy laminates and tubes

    DEFF Research Database (Denmark)

    Quaresimin, M.; Carraro, P.A.; Mikkelsen, Lars Pilgaard

    2014-01-01

    In this work an experimental investigation on damage initiation and evolution in laminates under cyclic loading is presented. The stacking sequence [0/θ2/0/-θ2]s has been adopted in order to investigate the influence of the local multiaxial stress state in the off-axis plies and the possible effect...

  12. "P.S.-I'm White Too": The Legacy of Evolution, Creationism, and Racism in the United States

    Science.gov (United States)

    Moore, Randy; Chung, Carl

    2005-01-01

    Despite decades of science education reform, creationism remains very popular in the United States. Although neither creationism nor evolution is inherently racist, creationists and evolutionists have used science to justify white supremacy. Powerful racist organizations such as the Ku Klux Klan and popular racist advocates such as Frank Norris…

  13. Nonstationary porosity evolution in mixing zone in coastal carbonate aquifer using an alternative modeling approach.

    Science.gov (United States)

    Laabidi, Ezzeddine; Bouhlila, Rachida

    2015-07-01

    In the last few decades, hydrogeochemical problems have benefited from the strong interest in numerical modeling. One of the most recognized hydrogeochemical problems is the dissolution of the calcite in the mixing zone below limestone coastal aquifer. In many works, this problem has been modeled using a coupling algorithm between a density-dependent flow model and a geochemical model. A related difficulty is that, because of the high nonlinearity of the coupled set of equations, high computational effort is needed. During calcite dissolution, an increase in permeability can be identified, which can induce an increase in the penetration of the seawater into the aquifer. The majority of the previous studies used a fully coupled reactive transport model in order to model such problem. Romanov and Dreybrodt (J Hydrol 329:661-673, 2006) have used an alternative approach to quantify the porosity evolution in mixing zone below coastal carbonate aquifer at steady state. This approach is based on the analytic solution presented by Phillips (1991) in his book Flow and Reactions in Permeable Rock, which shows that it is possible to decouple the complex set of equation. This equation is proportional to the square of the salinity gradient, which can be calculated using a density driven flow code and to the reaction rate that can be calculated using a geochemical code. In this work, this equation is used in nonstationary step-by-step regime. At each time step, the quantity of the dissolved calcite is quantified, the change of porosity is calculated, and the permeability is updated. The reaction rate, which is the second derivate of the calcium equilibrium concentration in the equation, is calculated using the PHREEQC code (Parkhurst and Apello 1999). This result is used in GEODENS (Bouhlila 1999; Bouhlila and Laabidi 2008) to calculate change of the porosity after calculating the salinity gradient. For the next time step, the same protocol is used but using the updated porosity

  14. Time-evolution of entanglement and Greenberger-Horne-Zeilinger states in two-mode Bose-Einstein condensates

    International Nuclear Information System (INIS)

    Yin Wen; Zhang, G.-F.; Liang, J.-Q.; Yan, Q.-W.

    2004-01-01

    In this Brief Report we investigate the time evolution of entanglement in two-mode Bose-Einstein condensates (BEC's) with various parameters of the scattering lengths of interatoms collisions, Josephson coupling strength, and initial states. The degree of entanglement increases by strengthening the tunnel coupling and keeping the balance of the collision interaction. In the latter stage we show that the two-mode BEC's can be used for preparing the Greenberger-Home-Zeilinger state

  15. Generalised linear models for correlated pseudo-observations, with applications to multi-state models

    DEFF Research Database (Denmark)

    Andersen, Per Kragh; Klein, John P.; Rosthøj, Susanne

    2003-01-01

    Generalised estimating equation; Generalised linear model; Jackknife pseudo-value; Logistic regression; Markov Model; Multi-state model......Generalised estimating equation; Generalised linear model; Jackknife pseudo-value; Logistic regression; Markov Model; Multi-state model...

  16. Mathematical modeling of the evolution of a simple biological system

    Digital Repository Service at National Institute of Oceanography (India)

    Gonsalves, M.J.B.D.; Neetu, S.; Krishnan, K.P.; Attri, K.; LokaBharathi, P.A.

    be constructed to simulate the observed movement. The comparison between the observed data and the predictions based on the model then tell us how satisfactory the model is. In physical systems the model is usually based on fundamental principles of physics...

  17. The evolution of process-based hydrologic models

    NARCIS (Netherlands)

    Clark, Martyn P.; Bierkens, Marc F.P.; Samaniego, Luis; Woods, Ross A.; Uijlenhoet, Remko; Bennett, Katrina E.; Pauwels, Valentijn R.N.; Cai, Xitian; Wood, Andrew W.; Peters-Lidard, Christa D.

    2017-01-01

    The diversity in hydrologic models has historically led to great controversy on the "correct" approach to process-based hydrologic modeling, with debates centered on the adequacy of process parameterizations, data limitations and uncertainty, and computational constraints on model analysis. In this

  18. A Model Ground State of Polyampholytes

    International Nuclear Information System (INIS)

    Wofling, S.; Kantor, Y.

    1998-01-01

    The ground state of randomly charged polyampholytes (polymers with positive and negatively charged groups along their backbone) is conjectured to have a structure similar to a necklace, made of weakly charged parts of the chain, compacting into globules, connected by highly charged stretched 'strings' attempted to quantify the qualitative necklace model, by suggesting a zero approximation model, in which the longest neutral segment of the polyampholyte forms a globule, while the remaining part will form a tail. Expanding this approximation, we suggest a specific necklace-type structure for the ground state of randomly charged polyampholyte's, where all the neutral parts of the chain compact into globules: The longest neutral segment compacts into a globule; in the remaining part of the chain, the longest neutral segment (the second longest neutral segment) compacts into a globule, then the third, and so on. A random sequence of charges is equivalent to a random walk, and a neutral segment is equivalent to a loop inside the random walk. We use analytical and Monte Carlo methods to investigate the size distribution of loops in a one-dimensional random walk. We show that the length of the nth longest neutral segment in a sequence of N monomers (or equivalently, the nth longest loop in a random walk of N steps) is proportional to N/n 2 , while the mean number of neutral segments increases as √N. The polyampholytes in the ground state within our model is found to have an average linear size proportional to dN, and an average surface area proportional to N 2/3

  19. CURRENT STATE AND EVOLUTION PERSPECTIVES FOR MANAGEMENT ACCOUNTING IN THE ENERGY SECTOR BY IMPLEMENTING THE ABC METHOD

    Directory of Open Access Journals (Sweden)

    Rof Letitia Maria

    2011-07-01

    Full Text Available Based on a controversial issue, namely determining and controlling costs in the energy sector, the present study falls within the scope of management accounting and control. This scientific approach was initiated as a result of personal research concerns in the area of accounting, starting from the need to know and quantify costs in a sector of the economy that is less exploited. The main objective of this scientific approach is to address the evolution of the energy sector in a national and international context, in terms of economy and finances, with the aim to underline the need to organize and conduct management accounting in this sector. We will present a few particularities of the energy system, the current status of implementation of a medium and long term strategy aimed at developing the energy sector, as well as the need to adopt modern costing methods in this sector, which ensure operative cost control and performance growth of the entities that operate in this sector. Information on the reviewed topic was conducted by studying the national and international literature in the field, by analyzing the associated legislation, by consulting specialized web-sites and various articles in the database. The main research methods used in this scientific approach were analysis and synthesis, and qualitative research was the type of used research. The results of the research will materialize in providing the necessary conditions for designing an econometric model for implementing the ABC method, the conceptual and ideological delimitation of the ABC method, the deepening of the positive and negative aspects that the implementation of the Activity Based Costing involves. The major implication for the researched field is ensuring success for the implementation of a modern costing method in the energy sector, underlining the shortcomings of the traditional costing methods. The added value of the paper consists in conducting a rigorous study of the

  20. Hybrid models for the simulation of microstructural evolution influenced by coupled, multiple physical processes

    Energy Technology Data Exchange (ETDEWEB)

    Tikare, Veena [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hernandez-Rivera, Efrain [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Madison, Jonathan D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Holm, Elizabeth Ann [Carnegie Mellon Univ., Pittsburgh, PA (United States); Patterson, Burton R. [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering; Homer, Eric R. [Brigham Young Univ., Provo, UT (United States). Dept. of Mechanical Engineering

    2013-09-01

    Most materials microstructural evolution processes progress with multiple processes occurring simultaneously. In this work, we have concentrated on the processes that are active in nuclear materials, in particular, nuclear fuels. These processes are coarsening, nucleation, differential diffusion, phase transformation, radiation-induced defect formation and swelling, often with temperature gradients present. All these couple and contribute to evolution that is unique to nuclear fuels and materials. Hybrid model that combines elements from the Potts Monte Carlo, phase-field models and others have been developed to address these multiple physical processes. These models are described and applied to several processes in this report. An important feature of the models developed are that they are coded as applications within SPPARKS, a Sandiadeveloped framework for simulation at the mesoscale of microstructural evolution processes by kinetic Monte Carlo methods. This makes these codes readily accessible and adaptable for future applications.

  1. Towards a phase field model of the microstructural evolution of duplex steel with experimental verification

    DEFF Research Database (Denmark)

    Poulsen, Stefan Othmar; Voorhees, P.W.; Lauridsen, Erik Mejdal

    2012-01-01

    A phase field model to study the microstructural evolution of a polycrystalline dual-phase material with conserved phase fraction has been implemented, and 2D simulations have been performed. For 2D simulations, the model predicts the cubic growth well-known for diffusion-controlled systems. Some...... interphase boundaries are found to show a persistent non-constant curvature, which seems to be a feature of multi-phase materials. Finally, it is briefly outlined how this model is to be applied to investigate microstructural evolution in duplex steel. © (2012) Trans Tech Publications, Switzerland....

  2. Solid-state dewetting of Au/Ni bilayers: The effect of alloying on morphology evolution

    International Nuclear Information System (INIS)

    Herz, A.; Wang, D.; Kups, Th.; Schaaf, P.

    2014-01-01

    The solid-state dewetting of thin Au/Ni bilayers deposited onto SiO 2 /Si substrates is investigated. A rapid thermal treatment is used to induce the dewetting process by an increase in temperature. The evolution of the (111) peaks of X-ray diffraction reveals a characteristic change due to mixing of Au and Ni. At low temperature, the Au-Ni thin film is found to break up at the phase boundaries and growing voids are shown to be surrounded by a Ni-rich phase. Branch-like void growth is observed. Upon annealing at increasing temperatures, Au-Ni solid solutions are formed well above the bulk equilibrium solubility of Au and Ni. It is found that this metastable phase formation makes the Au-Ni thin film less vulnerable to rupturing. Moreover, growth mode of still evolving voids changes into a more regular, faceted one due to alloying. Finally, it is shown that annealing above the miscibility gap forms supersaturated, well-oriented Au-Ni solid solution agglomerates via dewetting.

  3. Solid-state dewetting of Au/Ni bilayers: The effect of alloying on morphology evolution

    Energy Technology Data Exchange (ETDEWEB)

    Herz, A.; Wang, D., E-mail: dong.wang@tu-ilmenau.de; Kups, Th.; Schaaf, P. [Institute of Materials Engineering and Institute of Micro- and Nanotechnologies MacroNano, Chair Materials for Electronics and Electrical Engineering, TU Ilmenau, Ilmenau 98693 (Germany)

    2014-07-28

    The solid-state dewetting of thin Au/Ni bilayers deposited onto SiO{sub 2}/Si substrates is investigated. A rapid thermal treatment is used to induce the dewetting process by an increase in temperature. The evolution of the (111) peaks of X-ray diffraction reveals a characteristic change due to mixing of Au and Ni. At low temperature, the Au-Ni thin film is found to break up at the phase boundaries and growing voids are shown to be surrounded by a Ni-rich phase. Branch-like void growth is observed. Upon annealing at increasing temperatures, Au-Ni solid solutions are formed well above the bulk equilibrium solubility of Au and Ni. It is found that this metastable phase formation makes the Au-Ni thin film less vulnerable to rupturing. Moreover, growth mode of still evolving voids changes into a more regular, faceted one due to alloying. Finally, it is shown that annealing above the miscibility gap forms supersaturated, well-oriented Au-Ni solid solution agglomerates via dewetting.

  4. The 20 year evolution of an energy conversion course at the United States Military Academy

    International Nuclear Information System (INIS)

    Bailey, Margaret; Oezer Arnas, A.; Potter, Robert; Samples, Jerry W.

    2004-01-01

    Over the past several years, an energy conversion course offered by the Mechanical Engineering Program at the United States Military Academy in West Point, New York, has evolved into a cohesive series of lessons addressing three general topical areas: advanced thermodynamics, advanced mechanical system analysis, and direct energy conversion systems. Mechanical engineering majors enroll in Energy Conversion Systems (ME 472) during the fall semester of their senior year as an advanced elective. ME 472 builds directly on the material covered in Thermodynamics (EM 301) taken during the student's junior year. In the first segment of ME 472, the students study advanced thermodynamic topics including exergy and combustion analyses. The students then analyze various mechanical systems including refrigeration systems, internal combustion engines, boilers, and fossil fuel fired steam and gas turbine combined power plants. Exergetic efficiencies of various equipment and systems are determined. The final portion of the course covers direct energy conversion technology, including fuel cells, photovoltaics, thermoelectricity, thermionics and magnetohydrodynamics. Supplemental lessons on energy storage, semi-conductors and nonreactive energy sources (such as solar collectors, wind turbines, and hydroelectric plants) are included here. This paper discusses the evolution of ME 472 since its inception and explains the motivations for the course's progress

  5. Trophic State Evolution and Nutrient Trapping Capacity in a Transboundary Subtropical Reservoir: A 25-Year Study.

    Science.gov (United States)

    Cunha, Davi Gasparini Fernandes; Benassi, Simone Frederigi; de Falco, Patrícia Bortoletto; Calijuri, Maria do Carmo

    2016-03-01

    Artificial reservoirs have been used for drinking water supply, other human activities, flood control and pollution abatement worldwide, providing overall benefits to downstream water quality. Most reservoirs in Brazil were built during the 1970s, but their long-term patterns of trophic status, water chemistry, and nutrient removal are still not very well characterized. We aimed to evaluate water quality time series (1985-2010) data from the riverine and lacustrine zones of the transboundary Itaipu Reservoir (Brazil/Paraguay). We examined total phosphorus and nitrogen, chlorophyll a concentrations, water transparency, and phytoplankton density to look for spatial and temporal trends and correlations with trophic state evolution and nutrient retention. There was significant temporal and spatial water quality variation (P water quality and structure of the reservoir were mainly affected by one internal force (hydrodynamics) and one external force (upstream cascading reservoirs). Nutrient and chlorophyll a concentrations tended to be lower in the lacustrine zone and decreased over the 25-year timeframe. Reservoir operational features seemed to be limiting primary production and phytoplankton development, which exhibited a maximum density of 6050  org/mL. The relatively small nutrient concentrations in the riverine zone were probably related to the effect of the cascade reservoirs upstream of Itaipu and led to relatively low removal percentages. Our study suggested that water quality problems may be more pronounced immediately after the filling phase of the artificial reservoirs, associated with the initial decomposition of drowned vegetation at the very beginning of reservoir operation.

  6. Evolution of computational models in BioModels Database and the Physiome Model Repository.

    Science.gov (United States)

    Scharm, Martin; Gebhardt, Tom; Touré, Vasundra; Bagnacani, Andrea; Salehzadeh-Yazdi, Ali; Wolkenhauer, Olaf; Waltemath, Dagmar

    2018-04-12

    A useful model is one that is being (re)used. The development of a successful model does not finish with its publication. During reuse, models are being modified, i.e. expanded, corrected, and refined. Even small changes in the encoding of a model can, however, significantly affect its interpretation. Our motivation for the present study is to identify changes in models and make them transparent and traceable. We analysed 13734 models from BioModels Database and the Physiome Model Repository. For each model, we studied the frequencies and types of updates between its first and latest release. To demonstrate the impact of changes, we explored the history of a Repressilator model in BioModels Database. We observed continuous updates in the majority of models. Surprisingly, even the early models are still being modified. We furthermore detected that many updates target annotations, which improves the information one can gain from models. To support the analysis of changes in model repositories we developed MoSt, an online tool for visualisations of changes in models. The scripts used to generate the data and figures for this study are available from GitHub https://github.com/binfalse/BiVeS-StatsGenerator and as a Docker image at https://hub.docker.com/r/binfalse/bives-statsgenerator/ . The website https://most.bio.informatik.uni-rostock.de/ provides interactive access to model versions and their evolutionary statistics. The reuse of models is still impeded by a lack of trust and documentation. A detailed and transparent documentation of all aspects of the model, including its provenance, will improve this situation. Knowledge about a model's provenance can avoid the repetition of mistakes that others already faced. More insights are gained into how the system evolves from initial findings to a profound understanding. We argue that it is the responsibility of the maintainers of model repositories to offer transparent model provenance to their users.

  7. Dark energy equation of state parameter and its evolution at low redshift

    Energy Technology Data Exchange (ETDEWEB)

    Tripathi, Ashutosh; Sangwan, Archana; Jassal, H.K., E-mail: ashutosh_tripathi@fudan.edu.cn, E-mail: archanakumari@iisermohali.ac.in, E-mail: hkjassal@iisermohali.ac.in [Indian Institute of Science Education and Research Mohali, SAS Nagar, Mohali 140306, Punjab (India)

    2017-06-01

    In this paper, we constrain dark energy models using a compendium of observations at low redshifts. We consider the dark energy as a barotropic fluid, with the equation of state a constant as well the case where dark energy equation of state is a function of time. The observations considered here are Supernova Type Ia data, Baryon Acoustic Oscillation data and Hubble parameter measurements. We compare constraints obtained from these data and also do a combined analysis. The combined observational constraints put strong limits on variation of dark energy density with redshift. For varying dark energy models, the range of parameters preferred by the supernova type Ia data is in tension with the other low redshift distance measurements.

  8. A 2-categorical state sum model

    Energy Technology Data Exchange (ETDEWEB)

    Baratin, Aristide, E-mail: abaratin@uwaterloo.ca [Department of Applied Mathematics, University of Waterloo, 200 University Ave W, Waterloo, Ontario N2L 3G1 (Canada); Freidel, Laurent, E-mail: lfreidel@perimeterinstitute.ca [Perimeter Institute for Theoretical Physics, 31 Caroline Str. N, Waterloo, Ontario N2L 2Y5 (Canada)

    2015-01-15

    It has long been argued that higher categories provide the proper algebraic structure underlying state sum invariants of 4-manifolds. This idea has been refined recently, by proposing to use 2-groups and their representations as specific examples of 2-categories. The challenge has been to make these proposals fully explicit. Here, we give a concrete realization of this program. Building upon our earlier work with Baez and Wise on the representation theory of 2-groups, we construct a four-dimensional state sum model based on a categorified version of the Euclidean group. We define and explicitly compute the simplex weights, which may be viewed a categorified analogue of Racah-Wigner 6j-symbols. These weights solve a hexagon equation that encodes the formal invariance of the state sum under the Pachner moves of the triangulation. This result unravels the combinatorial formulation of the Feynman amplitudes of quantum field theory on flat spacetime proposed in A. Baratin and L. Freidel [Classical Quantum Gravity 24, 2027–2060 (2007)] which was shown to lead after gauge-fixing to Korepanov’s invariant of 4-manifolds.

  9. A model-data comparison of the Holocene global sea surface temperature evolution

    NARCIS (Netherlands)

    Lohmann, G.; Pfeiffer, M.; Laepple, T.; Leduc, G.; Kim, J.-H.

    2013-01-01

    We compare the ocean temperature evolution of the Holocene as simulated by climate models and reconstructed from marine temperature proxies. We use transient simulations from a coupled atmosphere-ocean general circulation model, as well as an ensemble of time slice simulations from the Paleoclimate

  10. Galactic chemical evolution in hierarchical formation models - I. Early-type galaxies in the local Universe

    NARCIS (Netherlands)

    Arrigoni, Matías; Trager, Scott C.; Somerville, Rachel S.; Gibson, Brad K.

    We study the metallicities and abundance ratios of early-type galaxies in cosmological semi-analytic models (SAMs) within the hierarchical galaxy formation paradigm. To achieve this we implemented a detailed galactic chemical evolution model and can now predict abundances of individual elements for

  11. Galactic chemical evolution in hierarchical formation models : I. Early-type galaxies in the local Universe

    NARCIS (Netherlands)

    Arrigoni, Matias; Trager, Scott C.; Somerville, Rachel S.; Gibson, Brad K.

    2010-01-01

    We study the metallicities and abundance ratios of early-type galaxies in cosmological semi-analytic models (SAMs) within the hierarchical galaxy formation paradigm. To achieve this we implemented a detailed galactic chemical evolution model and can now predict abundances of individual elements for

  12. Acoustic backscatter models of fish: Gradual or punctuated evolution

    Science.gov (United States)

    Horne, John K.

    2004-05-01

    Sound-scattering characteristics of aquatic organisms are routinely investigated using theoretical and numerical models. Development of the inverse approach by van Holliday and colleagues in the 1970s catalyzed the development and validation of backscatter models for fish and zooplankton. As the understanding of biological scattering properties increased, so did the number and computational sophistication of backscatter models. The complexity of data used to represent modeled organisms has also evolved in parallel to model development. Simple geometric shapes representing body components or the whole organism have been replaced by anatomically accurate representations derived from imaging sensors such as computer-aided tomography (CAT) scans. In contrast, Medwin and Clay (1998) recommend that fish and zooplankton should be described by simple theories and models, without acoustically superfluous extensions. Since van Holliday's early work, how has data and computational complexity influenced accuracy and precision of model predictions? How has the understanding of aquatic organism scattering properties increased? Significant steps in the history of model development will be identified and changes in model results will be characterized and compared. [Work supported by ONR and the Alaska Fisheries Science Center.

  13. Revivals and entanglement from initially entangled mixed states of a damped Jaynes-Cummings model

    International Nuclear Information System (INIS)

    Rendell, R.W.; Rajagopal, A.K.

    2003-01-01

    An exact density matrix of a phase-damped Jaynes-Cummings model (JCM) with entangled Bell-like initial states formed from a model two-state atom and sets of adjacent photon number states of a single-mode radiation field is presented. The entanglement of the initial states and the subsequent time evolution is assured by finding a positive lower bound on the concurrence of local 2x2 projections of the full 2x∞ JCM density matrix. It is found that the time evolution of the lower bound of the concurrence systematically captures the corresponding collapse and revival features in atomic inversion, relative entropies of atomic and radiation, mutual entropy, and quantum deficit. The atom and radiation subsystems exhibit alternating sets of collapses and revivals in a complementary fashion due to the initially mixed states of the atom and radiation employed here. This is in contrast with the result obtained when the initial state of the dissipationless system is a factored pure state of the atom and radiation, where the atomic and radiation entropies are necessarily the same. The magnitudes of the entanglement lower bound and the atomic and radiation revivals become larger as both the magnitude and phase of the Bell-like initial state contribution increase. The time evolution of the entropy difference of the total system and that of the radiation subsystem exhibit negative regions called 'supercorrelated' states which do not appear in the atomic subsystem. Entangled initial states are found to enhance this supercorrelated feature. Finally, the effect of phase damping is to randomize both the subsystems for asymptotically long times. It may be feasible to experimentally investigate the results presented here using the Rabi oscillation methods of microwave and optical cavity quantum electrodynamics since pure photon number states have recently been produced and observed

  14. EMPIRICAL WEIGHTED MODELLING ON INTER-COUNTY INEQUALITIES EVOLUTION AND TO TEST ECONOMICAL CONVERGENCE IN ROMANIA

    Directory of Open Access Journals (Sweden)

    Natalia\tMOROIANU‐DUMITRESCU

    2015-06-01

    Full Text Available During the last decades, the regional convergence process in Europe has attracted a considerable interest as a highly significant issue, especially after EU enlargement with the New Member States from Central and Eastern Europe. The most usual empirical approaches are using the β- and σ-convergence, originally developed by a series of neo-classical models. Up-to-date, the EU integration process was proven to be accompanied by an increase of the regional inequalities. In order to determine the existence of a similar increase of the inequalities between the administrative counties (NUTS3 included in the NUTS2 and NUTS1 regions of Romania, this paper provides an empirical modelling of economic convergence allowing to evaluate the level and evolution of the inter-regional inequalities over more than a decade period lasting from 1995 up to 2011. The paper presents the results of a large cross-sectional study of σ-convergence and weighted coefficient of variation, using GDP and population data obtained from the National Institute of Statistics of Romania. Both graphical representation including non-linear regression and the associated tables summarizing numerical values of the main statistical tests are demonstrating the impact of pre- accession policy on the economic development of all Romanian NUTS types. The clearly emphasised convergence in the middle time subinterval can be correlated with the pre-accession drastic changes on economic, political and social level, and with the opening of the Schengen borders for Romanian labor force in 2002.

  15. On theoretical models of gene expression evolution with random genetic drift and natural selection.

    Directory of Open Access Journals (Sweden)

    Osamu Ogasawara

    2009-11-01

    Full Text Available The relative contributions of natural selection and random genetic drift are a major source of debate in the study of gene expression evolution, which is hypothesized to serve as a bridge from molecular to phenotypic evolution. It has been suggested that the conflict between views is caused by the lack of a definite model of the neutral hypothesis, which can describe the long-run behavior of evolutionary change in mRNA abundance. Therefore previous studies have used inadequate analogies with the neutral prediction of other phenomena, such as amino acid or nucleotide sequence evolution, as the null hypothesis of their statistical inference.In this study, we introduced two novel theoretical models, one based on neutral drift and the other assuming natural selection, by focusing on a common property of the distribution of mRNA abundance among a variety of eukaryotic cells, which reflects the result of long-term evolution. Our results demonstrated that (1 our models can reproduce two independently found phenomena simultaneously: the time development of gene expression divergence and Zipf's law of the transcriptome; (2 cytological constraints can be explicitly formulated to describe long-term evolution; (3 the model assuming that natural selection optimized relative mRNA abundance was more consistent with previously published observations than the model of optimized absolute mRNA abundances.The models introduced in this study give a formulation of evolutionary change in the mRNA abundance of each gene as a stochastic process, on the basis of previously published observations. This model provides a foundation for interpreting observed data in studies of gene expression evolution, including identifying an adequate time scale for discriminating the effect of natural selection from that of random genetic drift of selectively neutral variations.

  16. Assessment of long-term channel changes in the Mekong River using remote sensing and a channel-evolution model

    Science.gov (United States)

    Miyazawa, N.

    2011-12-01

    River-channel changes are a key factor affecting physical, ecological and management issues in the fluvial environment. In this study, long-term channel changes in the Mekong River were assessed using remote sensing and a channel-evolution model. A channel-evolution model for calculating long-term channel changes of a measndering river was developed using a previous fluid-dynamic model [Zolezzi and Seminara, 2001], and was applied in order to quantify channel changes of two meandering reaches in the Mekong River. Quite few attempts have been made so far to combine remote sensing observation of meandering planform change with the application of channel evolution models within relatively small-scale gravel-bed systems in humid temperate regions. The novel point of the present work is to link state-of-art meandering planform evolution model with observed morphological changes within large-scale sand-bed rivers with higher bank height in tropical monsoonal climate regions, which are the highly dynamic system, and assess the performance. Unstable extents of the reaches could be historically identified using remote-sensing technique. The instability caused i) bank erosion and accretion of meander bends and ii) movement or development of bars and changes in the flow around the bars. The remote sensing measurements indicate that maximum erosion occurred downstream of the maximum curvature of the river-center line in both reaches. The model simulations indicates that under the mean annual peak discharge the maximum of excess longitudinal velocity near the banks occurs downstream of the maximum curvature in both reaches. The channel migration coefficients of the reaches were calibrated by comparing remote-sensing measurements and model simulations. The diffrence in the migration coefficients between both reaches depends on the diffrence in bank height rather than the geotechnical properties of floodplain sediments. Possible eroded floodplain areas and accreted floodplain

  17. Probabilistic models of population evolution scaling limits, genealogies and interactions

    CERN Document Server

    Pardoux, Étienne

    2016-01-01

    This expository book presents the mathematical description of evolutionary models of populations subject to interactions (e.g. competition) within the population. The author includes both models of finite populations, and limiting models as the size of the population tends to infinity. The size of the population is described as a random function of time and of the initial population (the ancestors at time 0). The genealogical tree of such a population is given. Most models imply that the population is bound to go extinct in finite time. It is explained when the interaction is strong enough so that the extinction time remains finite, when the ancestral population at time 0 goes to infinity. The material could be used for teaching stochastic processes, together with their applications. Étienne Pardoux is Professor at Aix-Marseille University, working in the field of Stochastic Analysis, stochastic partial differential equations, and probabilistic models in evolutionary biology and population genetics. He obtai...

  18. Clinical evaluation and evolution of colic cases associated with Panicum maximum in Mato Grosso State, Brazil

    Directory of Open Access Journals (Sweden)

    Renata Gebara Sampaio Dória

    2015-12-01

    Full Text Available ABSTRACT. Dória R.G.S., Freitas S.H., Laskoski L.M., Carvalho M.B., Monteiro A.O.N., Camplesi A.C. & Valadão C.A.A. [Clinical evaluation and evolution of colic cases associated with Panicum maximum in Mato Grosso State, Brazil.] Avaliação clínica e da evolução dos casos de cólica associados a Panicum maximum no Estado de Mato Grosso, Brasil. Revista Brasileira de Medicina Veterinária, 37(4:303-308, 2015. Departamento de Medicina Veterinária, Curso de Medicina Veterinária, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Av. Duque de Caxias Norte, 225, Centro, Pirassununga, SP 13635-900, Brasil. E-mail: redoria@usp.br An acute disease characterized by colic and timpanism was reported in Pará and Rondônia after horses fed with Panicum maximum cultivars Momba- ça, Tanzânia and Massai pasture grazing. In this study an acute abdomen case was experimentally reproduced after the ingestion of Panicum maximum var Massai pasture based on twenty two clinic and surgical cases of acute timpanic colic cases reported in a farm in the city of Cuiabá – MT, fed with Panicum maximum var Massai pasture, confirming the etiology and accompanying the clinical evolution of the disease. A horse kept in a stall fed only with Massai pasture was daily evaluated and it was verified that the animal presented as result a clinic perfil of pain, high cardiac frequency, respiratory difficulty, intestinal motility absence and exaggerated distention of the stomach and bowels by gas, seeing during the necropsy the stomach and bowels fully distended by gas with liquefied content except by small colon where the feces presented dry and with mucus characterizing the intestinal atony. The necessity of studies that search the identification of the agent responsible for the intestinal atony and gas accumulation in horses fed with Panicum maximum is exposed.

  19. Efficient determination of the Markovian time-evolution towards a steady-state of a complex open quantum system

    Science.gov (United States)

    Jonsson, Thorsteinn H.; Manolescu, Andrei; Goan, Hsi-Sheng; Abdullah, Nzar Rauf; Sitek, Anna; Tang, Chi-Shung; Gudmundsson, Vidar

    2017-11-01

    Master equations are commonly used to describe time evolution of open systems. We introduce a general computationally efficient method for calculating a Markovian solution of the Nakajima-Zwanzig generalized master equation. We do so for a time-dependent transport of interacting electrons through a complex nano scale system in a photon cavity. The central system, described by 120 many-body states in a Fock space, is weakly coupled to the external leads. The efficiency of the approach allows us to place the bias window defined by the external leads high into the many-body spectrum of the cavity photon-dressed states of the central system revealing a cascade of intermediate transitions as the system relaxes to a steady state. The very diverse relaxation times present in the open system, reflecting radiative or non-radiative transitions, require information about the time evolution through many orders of magnitude. In our approach, the generalized master equation is mapped from a many-body Fock space of states to a Liouville space of transitions. We show that this results in a linear equation which is solved exactly through an eigenvalue analysis, which supplies information on the steady state and the time evolution of the system.

  20. Medium-term erosion simulation of an abandoned mine site using the SIBERIA landscape evolution model

    International Nuclear Information System (INIS)

    Hancock, G.R.; Willgoose, G.R.

    2000-01-01

    This study forms part of a collaborative project designed to validate the long-term erosion predictions of the SIBERIA landform evolution model on rehabilitated mine sites. The SIBERIA catchment evolution model can simulate the evolution of landforms resulting from runoff and erosion over many years. SIBERIA needs to be calibrated before evaluating whether it correctly models the observed evolution of rehabilitated mine landforms. A field study to collect data to calibrate SIBERIA was conducted at the abandoned Scinto 6 uranium mine located in the Kakadu Region, Northern Territory, Australia. The data were used to fit parameter values to a sediment loss model and a rainfall-runoff model. The derived runoff and erosion model parameter values were used in SIBERIA to simulate 50 years of erosion by concentrated flow on the batters of the abandoned site. The SIBERIA runs correctly simulated the geomorphic development of the gullies on the man-made batters of the waste rock dump. The observed gully position, depth, volume, and morphology on the waste rock dump were quantitatively compared with the SIBERIA simulations. The close similarities between the observed and simulated gully features indicate that SIBERIA can accurately predict the rate of gully development on a man-made post-mining landscape over periods of up to 50 years. SIBERIA is an appropriate model for assessment of erosional stability of rehabilitated mine sites over time spans of around 50 years. Copyright (2000) CSIRO Australia

  1. Kinematic evolution of fold and thrust belts. Insights from experimental modeling

    International Nuclear Information System (INIS)

    Ueta, Keiichi

    2011-01-01

    Physical experiments were performed to gain a better understanding on the kinematic evolution of fold and thrust belts. The present study focuses on deformation of sedimentary cover caused by thrust and reverse movements along the basement fault. Our physical models comprise dry quartz sand representing brittle sedimentary rock and viscous silicone polymer representing overpressured mudstone. Computerized X-ray tomography was applied to the experiments to analyze the kinematic evolution of fold and thrust belts. In the sand models, the width of deformation zone above thrust was wider than that above reverse fault, because back thrust developed on the hanging wall of reverse fault. Within the physical models composed of dry sand and silicone polymer, minor folds and thrusts with minor displacement developed on the footwall of the major monoclinal flexure. These results compare well with the geometry and kinematic evolution of the fold and thrust belts in Japan. (author)

  2. Size Evolution and Stochastic Models: Explaining Ostracod Size through Probabilistic Distributions

    Science.gov (United States)

    Krawczyk, M.; Decker, S.; Heim, N. A.; Payne, J.

    2014-12-01

    The biovolume of animals has functioned as an important benchmark for measuring evolution throughout geologic time. In our project, we examined the observed average body size of ostracods over time in order to understand the mechanism of size evolution in these marine organisms. The body size of ostracods has varied since the beginning of the Ordovician, where the first true ostracods appeared. We created a stochastic branching model to create possible evolutionary trees of ostracod size. Using stratigraphic ranges for ostracods compiled from over 750 genera in the Treatise on Invertebrate Paleontology, we calculated overall speciation and extinction rates for our model. At each timestep in our model, new lineages can evolve or existing lineages can become extinct. Newly evolved lineages are assigned sizes based on their parent genera. We parameterized our model to generate neutral and directional changes in ostracod size to compare with the observed data. New sizes were chosen via a normal distribution, and the neutral model selected new sizes differentials centered on zero, allowing for an equal chance of larger or smaller ostracods at each speciation. Conversely, the directional model centered the distribution on a negative value, giving a larger chance of smaller ostracods. Our data strongly suggests that the overall direction of ostracod evolution has been following a model that directionally pushes mean ostracod size down, shying away from a neutral model. Our model was able to match the magnitude of size decrease. Our models had a constant linear decrease while the actual data had a much more rapid initial rate followed by a constant size. The nuance of the observed trends ultimately suggests a more complex method of size evolution. In conclusion, probabilistic methods can provide valuable insight into possible evolutionary mechanisms determining size evolution in ostracods.

  3. Linearized Flux Evolution (LiFE): A technique for rapidly adapting fluxes from full-physics radiative transfer models

    Science.gov (United States)

    Robinson, Tyler D.; Crisp, David

    2018-05-01

    Solar and thermal radiation are critical aspects of planetary climate, with gradients in radiative energy fluxes driving heating and cooling. Climate models require that radiative transfer tools be versatile, computationally efficient, and accurate. Here, we describe a technique that uses an accurate full-physics radiative transfer model to generate a set of atmospheric radiative quantities which can be used to linearly adapt radiative flux profiles to changes in the atmospheric and surface state-the Linearized Flux Evolution (LiFE) approach. These radiative quantities describe how each model layer in a plane-parallel atmosphere reflects and transmits light, as well as how the layer generates diffuse radiation by thermal emission and by scattering light from the direct solar beam. By computing derivatives of these layer radiative properties with respect to dynamic elements of the atmospheric state, we can then efficiently adapt the flux profiles computed by the full-physics model to new atmospheric states. We validate the LiFE approach, and then apply this approach to Mars, Earth, and Venus, demonstrating the information contained in the layer radiative properties and their derivatives, as well as how the LiFE approach can be used to determine the thermal structure of radiative and radiative-convective equilibrium states in one-dimensional atmospheric models.

  4. Data Analysis of Globular Cluster Harris Catalogue in View of the King Models and Their Dynamical Evolution. I. Theoretical model

    Directory of Open Access Journals (Sweden)

    Marco Merafina

    2014-12-01

    Full Text Available We discuss the possibility to analyze the problem of gravothermal catastrophe in a new way, by obtaining thermodynamical equations to apply to a selfgravitating system. By using the King distribution function in the framework of statistical mechanics we treat the globular clusters evolution as a sequence of quasi-equilibrium thermodynamical states.

  5. Numerical modelling of damage evolution in ingot forging

    DEFF Research Database (Denmark)

    Christiansen, Peter; Martins, Paulo A.F.; Bay, Niels Oluf

    2015-01-01

    The ingot forging process is numerically simulated applying both the Shima-Oyane porous plasticity model as a coupled damage model and the uncoupled normalized Cockcroft & Latham criterion. Four different cases including two different lower die angles (120º and 180º) and two different sizes of feed...... (400mm and 800mm) are analysed. Comparison of the simulation results with recommendations in literature on ingot forging, indicates the normalized Cockcroft & Latham damage criterion to be the most realistic of the two....

  6. Consistent Evolution of Software Artifacts and Non-Functional Models

    Science.gov (United States)

    2014-11-14

    induce bad software performance)? 15. SUBJECT TERMS EOARD, Nano particles, Photo-Acoustic Sensors, Model-Driven Engineering ( MDE ), Software Performance...Università degli Studi dell’Aquila, Via Vetoio, 67100 L’Aquila, Italy Email: vittorio.cortellessa@univaq.it Web : http: // www. di. univaq. it/ cortelle/ Phone...Model-Driven Engineering ( MDE ), Software Performance Engineering (SPE), Change Propagation, Performance Antipatterns. For sake of readability of the

  7. Modelling sediment dynamics due to hillslope-river interactions : incorporating fluvial behaviour in landscape evolution model LAPSUS

    NARCIS (Netherlands)

    Baartman, Jantiene E. M.; van Gorp, Wouter; Temme, Arnaud J. A. M.; Schoorl, Jeroen M.

    Landscape evolution models (LEMs) simulate the three-dimensional development of landscapes over time. Different LEMs have different foci, e.g. erosional behaviour, river dynamics, the fluvial domain, hillslopes or a combination. LEM LAPSUS is a relatively simple cellular model operating on

  8. Genetic demixing and evolution in linear stepping stone models

    Science.gov (United States)

    Korolev, K. S.; Avlund, Mikkel; Hallatschek, Oskar; Nelson, David R.

    2010-04-01

    Results for mutation, selection, genetic drift, and migration in a one-dimensional continuous population are reviewed and extended. The population is described by a continuous limit of the stepping stone model, which leads to the stochastic Fisher-Kolmogorov-Petrovsky-Piscounov equation with additional terms describing mutations. Although the stepping stone model was first proposed for population genetics, it is closely related to “voter models” of interest in nonequilibrium statistical mechanics. The stepping stone model can also be regarded as an approximation to the dynamics of a thin layer of actively growing pioneers at the frontier of a colony of micro-organisms undergoing a range expansion on a Petri dish. The population tends to segregate into monoallelic domains. This segregation slows down genetic drift and selection because these two evolutionary forces can only act at the boundaries between the domains; the effects of mutation, however, are not significantly affected by the segregation. Although fixation in the neutral well-mixed (or “zero-dimensional”) model occurs exponentially in time, it occurs only algebraically fast in the one-dimensional model. An unusual sublinear increase is also found in the variance of the spatially averaged allele frequency with time. If selection is weak, selective sweeps occur exponentially fast in both well-mixed and one-dimensional populations, but the time constants are different. The relatively unexplored problem of evolutionary dynamics at the edge of an expanding circular colony is studied as well. Also reviewed are how the observed patterns of genetic diversity can be used for statistical inference and the differences are highlighted between the well-mixed and one-dimensional models. Although the focus is on two alleles or variants, q -allele Potts-like models of gene segregation are considered as well. Most of the analytical results are checked with simulations and could be tested against recent spatial

  9. Standard cosmological evolution in the f(R) model to Kaluza-Klein cosmology

    International Nuclear Information System (INIS)

    Aghmohammadi, A; Abolhassani, M R; Saaidi, Kh; Vajdi, A

    2009-01-01

    In this paper, using f(R) theory of gravity we explicitly calculate cosmological evolution in the presence of a perfect fluid source in four- and five-dimensional space-time in which this cosmological evolution in self-creation is presented by Reddy et al (2009 Int. J. Theor. Phys. 48 10). An exact cosmological model is presented using a relation between Einstein's gravity field equation components due to a metric with the same component from f(R) theory of gravity. Some physics and kinematical properties of the model are also discussed.

  10. Mesoscale modeling and simulation of microstructure evolution during dynamic recrystallization of a Ni-based superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Fei [University of Nottingham, Department of Mechanical, Materials and Manufacturing Engineering, Nottingham (United Kingdom); Shanghai Jiao Tong University, Institute of Forming Technology and Equipment, Shanghai (China); Cui, Zhenshan [Shanghai Jiao Tong University, Institute of Forming Technology and Equipment, Shanghai (China); Ou, Hengan [University of Nottingham, Department of Mechanical, Materials and Manufacturing Engineering, Nottingham (United Kingdom); Long, Hui [University of Sheffield, Department of Mechanical Engineering, Sheffield (United Kingdom)

    2016-10-15

    Microstructural evolution and plastic flow characteristics of a Ni-based superalloy were investigated using a simulative model that couples the basic metallurgical principle of dynamic recrystallization (DRX) with the two-dimensional (2D) cellular automaton (CA). Variation of dislocation density with local strain of deformation is considered for accurate determination of the microstructural evolution during DRX. The grain topography, the grain size and the recrystallized fraction can be well predicted by using the developed CA model, which enables to the establishment of the relationship between the flow stress, dislocation density, recrystallized fraction volume, recrystallized grain size and the thermomechanical parameters. (orig.)

  11. Numerical modeling of plasma plume evolution against ambient background gas in laser blow off experiments

    International Nuclear Information System (INIS)

    Patel, Bhavesh G.; Das, Amita; Kaw, Predhiman; Singh, Rajesh; Kumar, Ajai

    2012-01-01

    Two dimensional numerical modelling based on simplified hydrodynamic evolution for an expanding plasma plume (created by laser blow off) against an ambient background gas has been carried out. A comparison with experimental observations shows that these simulations capture most features of the plasma plume expansion. The plume location and other gross features are reproduced as per the experimental observation in quantitative detail. The plume shape evolution and its dependence on the ambient background gas are in good qualitative agreement with the experiment. This suggests that a simplified hydrodynamic expansion model is adequate for the description of plasma plume expansion.

  12. Generalized time evolution of the homogeneous cooling state of a granular gas with positive and negative coefficient of normal restitution

    Science.gov (United States)

    Khalil, Nagi

    2018-04-01

    The homogeneous cooling state (HCS) of a granular gas described by the inelastic Boltzmann equation is reconsidered. As usual, particles are taken as inelastic hard disks or spheres, but now the coefficient of normal restitution α is allowed to take negative values , which is a simple way of modeling more complicated inelastic interactions. The distribution function of the HCS is studied at the long-time limit, as well as intermediate times. At the long-time limit, the relevant information of the HCS is given by a scaling distribution function , where the time dependence occurs through a dimensionless velocity c. For , remains close to the Gaussian distribution in the thermal region, its cumulants and exponential tails being well described by the first Sonine approximation. In contrast, for , the distribution function becomes multimodal, its maxima located at , and its observable tails algebraic. The latter is a consequence of an unbalanced relaxation–dissipation competition, and is analytically demonstrated for , thanks to a reduction of the Boltzmann equation to a Fokker–Plank-like equation. Finally, a generalized scaling solution to the Boltzmann equation is also found . Apart from the time dependence occurring through the dimensionless velocity, depends on time through a new parameter β measuring the departure of the HCS from its long-time limit. It is shown that describes the time evolution of the HCS for almost all times. The relevance of the new scaling is also discussed.

  13. Solid-state fermentation : modelling fungal growth and activity

    NARCIS (Netherlands)

    Smits, J.P.

    1998-01-01

    In solid-state fermentation (SSF) research, it is not possible to separate biomass quantitatively from the substrate. The evolution of biomass dry weight in time can therefore not be measured. Of the aiternatives to dry weight available, glucosamine content is most

  14. Existence and uniqueness of Gibbs states for a statistical mechanical polyacetylene model

    International Nuclear Information System (INIS)

    Park, Y.M.

    1987-01-01

    One-dimensional polyacetylene is studied as a model of statistical mechanics. In a semiclassical approximation the system is equivalent to a quantum XY model interacting with unbounded classical spins in one-dimensional lattice space Z. By establishing uniform estimates, an infinite-volume-limit Hilbert space, a strongly continuous time evolution group of unitary operators, and an invariant vector are constructed. Moreover, it is proven that any infinite-limit state satisfies Gibbs conditions. Finally, a modification of Araki's relative entropy method is used to establish the uniqueness of Gibbs states

  15. The effect of system modeling on the Fukushima accident evolution

    Energy Technology Data Exchange (ETDEWEB)

    Herranz, L.E.; Fontanet, J.; López, C.; Fernández, E.

    2015-07-01

    The Fukushima accident is becoming both a unique opportunity and a huge challenge for severe accident analysis. The OECD-BSAF project has articulated a good part of the modeling efforts conducted so far. Inside this project, CIEMAT has conducted forensic analyses of the Fukushima accident in units 1 through 3 with MELCOR 2.1 and it has postulated a set of accident scenarios consistent with data. Beyond specific results, sensitivity analyses on safety systems performance and prevailing boundary conditions have highlighted the need of conducting uncertainty analyses when modeling NPPs severe accident scenarios. (Author)

  16. A compact cyclic plasticity model with parameter evolution

    DEFF Research Database (Denmark)

    Krenk, Steen; Tidemann, L.

    2017-01-01

    The paper presents a compact model for cyclic plasticity based on energy in terms of external and internal variables, and plastic yielding described by kinematic hardening and a flow potential with an additive term controlling the nonlinear cyclic hardening. The model is basically described by five...... parameters: external and internal stiffness, a yield stress and a limiting ultimate stress, and finally a parameter controlling the gradual development of plastic deformation. Calibration against numerous experimental results indicates that typically larger plastic strains develop than predicted...

  17. The Evolution of Building a Diverse Geosciences in the United States

    Science.gov (United States)

    Keane, Christopher; Houlton, Heather; Leahy, P. Patrick

    2016-04-01

    Since the 1960s, the United States has had numerous systematic efforts to support diversity in all parts of society. The American Geosciences Institute has had active ongoing research and diversity promotion programs in the geosciences since 1972. Over this time, the drivers and goals of promoting a diverse discipline have evolved, including in the scope and definition of diversity. The success of these efforts have been mixed, largely driven by wildly different responses by specific gender and racial subsets of the population. Some critical cultural barriers have been solidly identified and mitigation approaches promoted. For example, the use of field work in promotion of geoscience careers and education programs is viewed as a distinct negative by many African American and Hispanic communities as it equates geoscience as non-professional work. Similarly, efforts at improving gender diversity have had great success, especially in the private sector, as life-balance policies and mitigations of implicit biases have been addressed. Yet success in addressing some of these cultural and behavioral issues has also started to unveil other overarching factors, such as the role of socio-economic and geographic location. Recent critical changes in the definition of diversity that have been implemented will be discussed. These include dropping Asian races as underrepresented, the introduction of the multiracial definition, evolution of the nature of gender, and the increased awareness of persons with disabilities as a critical diverse population. This has been coupled with dramatic changes in the drivers for promoting diversity in the geosciences in the U.S. from a moral and ethical good to one of economic imperative and recognizing the way to access the best talent in the population as the U.S. rapidly approaches being a majority minority society. These changes are leading to new approaches and strategies, for which we will highlight specific programmatic efforts both by AGI

  18. Inelastic properties evolution of alloy steels in martensitic and cold-worked states subjected to heat treatments up to 600/sup 0/C

    Energy Technology Data Exchange (ETDEWEB)

    Isore, A; Miyada, L T

    1975-05-01

    Two internal friction peaks were observed in a ball-bearing steel in the martensitic and cold-worked states, near 220 and 280/sup 0/C for a frequency of about 1,3 Hz. From peaks evolution by annealing up to 600/sup 0/C, it is possible to follow the decomposition stages of martensitic and recrystallization of cold-worked pearlite. Annealed martensite and cold worked pearlite have the same anelastic behaviour. From existing atomistic models, it is possible to interpret these peaks by dislocations-interstitial carbon and dislocations-carbides interactions.

  19. Inelastic properties evolution of alloy steels in martensitic and cold-worked states subjected to heat treatments up to 6000C

    International Nuclear Information System (INIS)

    Isore, A.; Miyada, L.T.

    1975-01-01

    Two internal friction peaks were observed in a ball-bearing steel in the martensitic and cold-worked states, near 220 and 280 0 C for a frequency of about 1,3 Hz. From peaks evolution by annealing up to 600 0 C, it is possible to follow the decomposition stages of martensitic and recrystallization of cold-worked pearlite. Annealed martensite and cold worked pearlite have the same anelastic behaviour. From existing atomistic models, it is possible to interpret these peaks by dislocations-interstitial carbon and dislocations-carbides interactions

  20. An agent based model of the evolution of supplier networks

    DEFF Research Database (Denmark)

    Earnest, David C.; Wilkinson, Ian F.

    2018-01-01

    , in industries characterized by highly specialized training, plants and machinery dedicated to specific products and other high product-specific transaction costs, we should observe more specialization at low levels of product complexity but less at high levels. The model contributes to our understanding...

  1. Algorithm for dealing with depressions in dynamic landscape evolution models

    NARCIS (Netherlands)

    Temme, A.J.A.M.; Schoorl, J.M.; Veldkamp, A.

    2006-01-01

    Depressions in landscapes function as buffers for water and sediment. A landscape with depressions has less runoff, less erosion and more sedimentation than a landscape without depressions. Sinks in digital elevation models (DEMs) can be existing features that correctly represent depressions in

  2. Cancer evolution and immunity in a rat colorectal carcinogenesis model

    Czech Academy of Sciences Publication Activity Database

    Vannucci, Luca; Fišerová, Anna; Horváth, Ondřej; Rossmann, Pavel; Mosca, F.; Pospíšil, Miloslav

    2004-01-01

    Roč. 25, - (2004), s. 973-981 ISSN 1019-6439 R&D Projects: GA ČR GV312/98/K034; GA AV ČR IAA7020006 Institutional research plan: CEZ:AV0Z5020903 Keywords : cancer * cancer model * colorectal adenocarcinoma Subject RIV: EE - Microbiology, Virology Impact factor: 3.056, year: 2004

  3. The Historical Evolution of Theories and Conceptual Models for Nursing.

    Science.gov (United States)

    Hawkins, Joellen W.

    The development of nursing models can be traced to the inception of nursing as a profession. Florence Nightingale laid the foundation for current nursing practice and differentiated nursing from medicine. The late 19th and early 20th centuries contributed a number of important nurse theorists, better known for other contributions to the neophyte…

  4. Schumpeterian economic dynamics as a quantifiable model of evolution

    Science.gov (United States)

    Thurner, Stefan; Klimek, Peter; Hanel, Rudolf

    2010-07-01

    We propose a simple quantitative model of Schumpeterian economic dynamics. New goods and services are endogenously produced through combinations of existing goods. As soon as new goods enter the market, they may compete against already existing goods. In other words, new products can have destructive effects on existing goods. As a result of this competition mechanism, existing goods may be driven out from the market—often causing cascades of secondary defects (Schumpeterian gales of destruction). The model leads to generic dynamics characterized by phases of relative economic stability followed by phases of massive restructuring of markets—which could be interpreted as Schumpeterian business 'cycles'. Model time series of product diversity and productivity reproduce several stylized facts of economics time series on long timescales, such as GDP or business failures, including non-Gaussian fat tailed distributions and volatility clustering. The model is phrased in an open, non-equilibrium setup which can be understood as a self-organized critical system. Its diversity dynamics can be understood by the time-varying topology of the active production networks.

  5. Land destruction and redevelopment - the use of computer based landscape evolution models for post-mining landscape reconstruction

    Science.gov (United States)

    Hancock, Greg; Willgoose, Garry

    2017-04-01

    Mining provides essential resources for the global economy as well as considerable employment and economic benefits for the community. Mining is necessary for the modern economy. However, in recent decades the scale and environmental impact of mining has grown in line with the global demand for resources. This requires ever increasing areas of land to be disturbed. In particular, open-cast mining removes topsoil, disrupts aquifers and removes uneconomic material to depths of many hundreds of metres. Post-mining, this highly disturbed landscape system requires rehabilitation. The first and most important component of this process is to construct an erosionally stable landform which then can ecologically integrate with the surrounding undisturbed landscape. The scale and importance of this process cannot be overstated as without planned rehabilitation it is likely that a degraded and highly erosional landscape system with result. Here we discuss computer based landform evolution models which provide essential information on the likely erosional stability of the reconstructed landscape. These models use a digital elevation model to represent the landscape and dynamically adjusts the surface in response to erosion and deposition. They provide information on soil erosion rates at the storm event time scale through to annual time scales. The models can also be run to assess landscape evolution at millennial time scales. They also provide information on the type of erosion (i.e. rilling, gullying) and likely gully depths (and if they will occur). Importantly, the latest models have vegetation, armouring and pedogenesis submodels incorporated into their formulation. This allows both the surface and subsurface landscape evolution to be assessed. These models have been widely used and have huge benefits for the assessment of reconstructed landscapes as well as other disturbed landscape systems. Here we outline the state of the art.

  6. Evolution of the Bangalore ICT Cluster: The "Crystal Growth" Model

    Science.gov (United States)

    Manimala, Mathew J.

    2006-01-01

    In about twenty years, starting in 1984, Bangalore has become the fourth best "Global Hub of Technological Innovation", according to Business Week. This article reviews the major milestones in Bangalore's development and the interactive roles of government, universities and private entrepreneurs. The author offers a new model: innovation…

  7. On the Tidal Evolution of the Earth-Moon System: A Cosmological Model

    Directory of Open Access Journals (Sweden)

    Arbab A. I.

    2009-01-01

    Full Text Available We have presented a cosmological model for the tidal evolution of the Earth-Moon system. We have found that the expansion of the universe has immense consequences on our local systems. The model can be compared with the present observational data. The close approach problem inflicting the known tidal theory is averted in this model. We have also shown that the astronomical and geological changes of our local systems are of the order of Hubble constant.

  8. Geochemical modelling study on the age and evolution of the groundwater at the Romuvaara site

    Energy Technology Data Exchange (ETDEWEB)

    Pitkaenen, P; Vuorinen, U; Leino-Forsman, H [Technical Research Centre of Finland, Espoo (Finland); Snellman, M [Imatran Voima Oy, Helsinki (Finland)

    1996-09-01

    The objective of the study was to interpret the processes and factors which control the hydrogeochemistry (e.g. pH and redox conditions) in the radioactive waste disposal environment. A model of the hydrogeochemical evolution and the chemical flowpaths in different parts of the bedrock at the Romuvaara (in Finland) site has been created. The significance of chemical reactions along different flowpaths is calculated. Furthermore, the consistency of the hydrogeochemical model and the hydrogeological model is examined. (107 refs.).

  9. Modeling the evolution of natural cliffs subject to weathering. 1, Limit analysis approach

    OpenAIRE

    Utili, Stefano; Crosta, Giovanni B.

    2011-01-01

    Retrogressive landsliding evolution of natural slopes subjected to weathering has been modeled by assuming Mohr-Coulomb material behavior and by using an analytical method. The case of weathering-limited slope conditions, with complete erosion of the accumulated debris, has been modeled. The limit analysis upper-bound method is used to study slope instability induced by a homogeneous decrease of material strength in space and time. The only assumption required in the model concerns the degree...

  10. Geochemical modelling study on the age and evolution of the groundwater at the Romuvaara site

    International Nuclear Information System (INIS)

    Pitkaenen, P.; Vuorinen, U.; Leino-Forsman, H.; Snellman, M.

    1996-09-01

    The objective of the study was to interpret the processes and factors which control the hydrogeochemistry (e.g. pH and redox conditions) in the radioactive waste disposal environment. A model of the hydrogeochemical evolution and the chemical flowpaths in different parts of the bedrock at the Romuvaara (in Finland) site has been created. The significance of chemical reactions along different flowpaths is calculated. Furthermore, the consistency of the hydrogeochemical model and the hydrogeological model is examined. (107 refs.)

  11. Space evolution model and empirical analysis of an urban public transport network

    Science.gov (United States)

    Sui, Yi; Shao, Feng-jing; Sun, Ren-cheng; Li, Shu-jing

    2012-07-01

    This study explores the space evolution of an urban public transport network, using empirical evidence and a simulation model validated on that data. Public transport patterns primarily depend on traffic spatial-distribution, demands of passengers and expected utility of investors. Evolution is an iterative process of satisfying the needs of passengers and investors based on a given traffic spatial-distribution. The temporal change of urban public transport network is evaluated both using topological measures and spatial ones. The simulation model is validated using empirical data from nine big cities in China. Statistical analyses on topological and spatial attributes suggest that an evolution network with traffic demands characterized by power-law numerical values which distribute in a mode of concentric circles tallies well with these nine cities.

  12. CoMET: A Mesquite package for comparing models of continuous character evolution on phylogenies

    Directory of Open Access Journals (Sweden)

    Chunghau Lee

    2006-01-01

    Full Text Available Continuously varying traits such as body size or gene expression level evolve during the history of species or gene lineages. To test hypotheses about the evolution of such traits, the maximum likelihood (ML method is often used. Here we introduce CoMET (Continuous-character Model Evaluation and Testing, which is module for Mesquite that automates likelihood computations for nine different models of trait evolution. Due to its few restrictions on input data, CoMET is applicable to testing a wide range of character evolution hypotheses. The CoMET homepage, which links to freely available software and more detailed usage instructions, is located at http://www.lifesci.ucsb.edu/eemb/labs/oakley/software/comet.htm.

  13. Nonlinear effects in evolution - an ab initio study: A model in which the classical theory of evolution occurs as a special case.

    Science.gov (United States)

    Clerc, Daryl G

    2016-07-21

    An ab initio approach was used to study the molecular-level interactions that connect gene-mutation to changes in an organism׳s phenotype. The study provides new insights into the evolutionary process and presents a simplification whereby changes in phenotypic properties may be studied in terms of the binding affinities of the chemical interactions affected by mutation, rather than by correlation to the genes. The study also reports the role that nonlinear effects play in the progression of organs, and how those effects relate to the classical theory of evolution. Results indicate that the classical theory of evolution occurs as a special case within the ab initio model - a case having two attributes. The first attribute: proteins and promoter regions are not shared among organs. The second attribute: continuous limiting behavior exists in the physical properties of organs as well as in the binding affinity of the associated chemical interactions, with respect to displacements in the chemical properties of proteins and promoter regions induced by mutation. Outside of the special case, second-order coupling contributions are significant and nonlinear effects play an important role, a result corroborated by analyses of published activity levels in binding and transactivation assays. Further, gradations in the state of perfection of an organ may be small or large depending on the type of mutation, and not necessarily closely-separated as maintained by the classical theory. Results also indicate that organs progress with varying degrees of interdependence, the likelihood of successful mutation decreases with increasing complexity of the affected chemical system, and differences between the ab initio model and the classical theory increase with increasing complexity of the organism. Copyright © 2016 The Author. Published by Elsevier Ltd.. All rights reserved.

  14. Peukert-Equation-Based State-of-Charge Estimation for LiFePO4 Batteries Considering the Battery Thermal Evolution Effect

    Directory of Open Access Journals (Sweden)

    Jiale Xie

    2018-05-01

    Full Text Available To achieve accurate state-of-charge (SoC estimation for LiFePO4 (lithium iron phosphate batteries under harsh conditions, this paper resorts to the Peukert’s law to accommodate different temperatures and load excitations. By analyzing battery heat generation and dissipation, a thermal evolution model (TEM is elaborated and exploited for on-line parameter identification of the equivalent circuit model (ECM. Then, a SoC estimation framework is proposed based on the Adaptive Extended Kalman Filter (AEKF algorithm. Experimental results on a LiFePO4 pack subject to the Federal Urban Driving Schedule (FUDS profile under different temperatures and initial states suggest that the proposed SoC estimator provides good robustness and accuracy against changing temperature and highly dynamic loads.

  15. Evolution operators and transformation of states under uniform and an/or elastic forces into free particle states

    International Nuclear Information System (INIS)

    Dattoli, G.; Torre, A.

    1999-01-01

    In this paper are exploited the techniques, associated with the evolution operator method, to prove the existence of a one-to one correspondence between the wave function of a free particle and those of a particle ruled by a quadratic Hamiltonian [it

  16. LHCb: The Evolution of the LHCb Grid Computing Model

    CERN Multimedia

    Arrabito, L; Bouvet, D; Cattaneo, M; Charpentier, P; Clarke, P; Closier, J; Franchini, P; Graciani, R; Lanciotti, E; Mendez, V; Perazzini, S; Nandkumar, R; Remenska, D; Roiser, S; Romanovskiy, V; Santinelli, R; Stagni, F; Tsaregorodtsev, A; Ubeda Garcia, M; Vedaee, A; Zhelezov, A

    2012-01-01

    The increase of luminosity in the LHC during its second year of operation (2011) was achieved by delivering more protons per bunch and increasing the number of bunches. Taking advantage of these changed conditions, LHCb ran with a higher pileup as well as a much larger charm physics introducing a bigger event size and processing times. These changes led to shortages in the offline distributed data processing resources, an increased need of cpu capacity by a factor 2 for reconstruction, higher storage needs at T1 sites by 70\\% and subsequently problems with data throughput for file access from the storage elements. To accommodate these changes the online running conditions and the Computing Model for offline data processing had to be adapted accordingly. This paper describes the changes implemented for the offline data processing on the Grid, relaxing the Monarc model in a first step and going beyond it subsequently. It further describes other operational issues discovered and solved during 2011, present the ...

  17. Isotope and trace element models of crustal evolution

    International Nuclear Information System (INIS)

    O'Nions, R.K.; Hamilton, P.J.

    1981-01-01

    Some of the isotopic constraints on the development of continental crust from about 3.8 Ga ago are reviewed. Particularly it is noted that Archaean granitic (sensu lato) rocks have initial 143 Nd/ 144 Nd ratios close to predicted values for the bulk Earth at the time before emplacement, whereas those Phanerozoic granites investigated so far diverge considerably from the bulk Earth and betray the existence of later continental crust in their provenance. Geochemical evidence for recycling of some continent-derived elements into the mantle is examined and the important distinction between selected element recycling and bulk return of continental material is emphasized. Various transport models that have been proposed to model the development of continental crust are examined and some of their differences and similarities, particularly with respect to implications for continental recycling, are highlighted. (author)

  18. The Use of Evolution in a Central Action Selection Model

    Directory of Open Access Journals (Sweden)

    F. Montes-Gonzalez

    2007-01-01

    Full Text Available The use of effective central selection provides flexibility in design by offering modularity and extensibility. In earlier papers we have focused on the development of a simple centralized selection mechanism. Our current goal is to integrate evolutionary methods in the design of non-sequential behaviours and the tuning of specific parameters of the selection model. The foraging behaviour of an animal robot (animat has been modelled in order to integrate the sensory information from the robot to perform selection that is nearly optimized by the use of genetic algorithms. In this paper we present how selection through optimization finally arranges the pattern of presented behaviours for the foraging task. Hence, the execution of specific parts in a behavioural pattern may be ruled out by the tuning of these parameters. Furthermore, the intensive use of colour segmentation from a colour camera for locating a cylinder sets a burden on the calculations carried out by the genetic algorithm.

  19. The Evolution of the Roskilde Model in Denmark

    DEFF Research Database (Denmark)

    Andersen, Anders Siig; Wulf-Andersen, Trine Østergaard; Heilesen, Simon

    2015-01-01

    For four decades, teaching at Roskilde University has been based on a research-active curriculum (Healey and Jenkins 2009, 122) mainstreaming research-based learning for all undergraduates and graduates. Problem-oriented project learning (PPL) is the cornerstone of a university-wide system...... work with a concrete example. The article also outline two different approaches to innovate using the Roskilde model of PPL....

  20. Time evolution in a geometric model of a particle

    International Nuclear Information System (INIS)

    Atiyah, M.F.; Franchetti, G.; Schroers, B.J.

    2015-01-01

    We analyse the properties of a (4+1)-dimensional Ricci-flat spacetime which may be viewed as an evolving Taub-NUT geometry, and give exact solutions of the Maxwell and gauged Dirac equation on this background. We interpret these solutions in terms of a geometric model of the electron and its spin, and discuss links between the resulting picture and Dirac’s Large Number Hypothesis.

  1. PROFESSIONAL COMPETITIVE EVOLUTION AND QUANTIFICATION MODELS IN ACCOUNTING SERVICE ELABORATION

    Directory of Open Access Journals (Sweden)

    Gheorghe FATACEAN

    2013-12-01

    Full Text Available The objective of this article consists in using an assessment framework of the accounting service elaboration. The purpose of this model is the identification and revaluation of an elite group of expert accounts from Romania, which should provide solutions to solve the most complex legal matters in the legal field, in the field of criminal, tax, civil, or commercial clauses making the object of law suits.

  2. Phase Transition Behavior in a Neutral Evolution Model

    Science.gov (United States)

    King, Dawn; Scott, Adam; Maric, Nevena; Bahar, Sonya

    2014-03-01

    The complexity of interactions among individuals and between individuals and the environment make agent based modeling ideal for studying emergent speciation. This is a dynamically complex problem that can be characterized via the critical behavior of a continuous phase transition. Concomitant with the main tenets of natural selection, we allow organisms to reproduce, mutate, and die within a neutral phenotype space. Previous work has shown phase transition behavior in an assortative mating model with variable fitness landscapes as the maximum mutation size (μ) was varied (Dees and Bahar, 2010). Similarly, this behavior was recently presented in the work of Scott et al. (2013), even on a completely neutral landscape, for bacterial-like fission as well as for assortative mating. Here we present another neutral model to investigate the `critical' phase transition behavior of three mating types - assortative, bacterial, and random - in a phenotype space as a function of the percentage of random death. Results show two types of phase transitions occurring for the parameters of the population size and the number of clusters (an analogue of species), indicating different evolutionary dynamics for system survival and clustering. This research was supported by funding from: University of Missouri Research Board and James S. McDonnell Foundation.

  3. Nuclear shape evolution starting from superdeformed state. Role of two-body collision and rotation

    International Nuclear Information System (INIS)

    Liu, Yu-xin; Sakata, Fumihiko

    1999-01-01

    With the nuclear density distribution being simulated by the Boltzmann Uehling-Uhlenbeck equation and Vlasov equation with several rotational frequencies, the time evolution of the quadrupole moment of nucleus 86 Zr starting with superdeformed shape is studied. The contribution of two-body collisions and the effects of collective rotation to the shape evolution is investigated. The numerical results indicate that the two-body collisions play a role of damping on the evolution from a superdeformed shape to a normal deformed one in a case without rotation. In a case of rotation with lower frequency, the two-body collisions accelerate the evolution process. A new role of the collective rotation to enhance the nuclear fission is proposed. (author)

  4. The Evolution of the Internet in Ethiopia and Rwanda: Towards a “Developmental” Model?

    Directory of Open Access Journals (Sweden)

    Iginio Gagliardone

    2016-08-01

    Full Text Available The Internet in Africa has become an increasingly contested space, where competing ideas of development and society battle for hegemony. By comparing the evolution of the Internet in Ethiopia and Rwanda, we question whether policies and projects emerging from two of Africa’s fastest growing, but also most tightly controlled countries, can be understood as part of a relatively cohesive model of the ‘developmental’ Internet, which challenges mainstream conceptions. Our answer is a qualified yes. Ethiopia and Rwanda have shared an overarching strategy which places the state as the prime mover in the development of Internet policy and large-scale ICT projects. Rwanda, however, appears to have developed a more open model which can accommodate a greater variety of actors and opinions, and incorporate them within a relatively coherent vision that emanates from the centre. Ethiopia, in contrast, has developed a more closed model, where all powers rest firmly in the hands of a government that has refused (so far to entertain and engage with alternative ideas of the Internet. In the case of Rwanda, we argue, this approach reflects broader strategies adopted by the government in the economic domain but appears to counter the prevailing political approach of the government, allowing for a greater degree of freedom on the Internet as compared to traditional media. While in the case of Ethiopia, the opposite is true; Ethiopia’s Internet policies appear to run counter to prevailing economic policies but fit tightly with the government’s approach to politics and governance.

  5. The evolution of ion charge states in cathodic vacuum arc plasmas: a review

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre

    2011-12-18

    Cathodic vacuum arc plasmas are known to contain multiply charged ions. 20 years after “Pressure Ionization: its role in metal vapour vacuum arc plasmas and ion sources” appeared in vol. 1 of Plasma Sources Science and Technology, it is a great opportunity to re-visit the issue of pressure ionization, a non-ideal plasma effect, and put it in perspective to the many other factors that influence observable charge state distributions, such as the role of the cathode material, the path in the density-temperature phase diagram, the “noise” in vacuum arc plasma as described by a fractal model approach, the effects of external magnetic fields and charge exchange collisions with neutrals. A much more complex image of the vacuum arc plasma emerges putting decades of experimentation and modeling in perspective.

  6. POET: A Model for Planetary Orbital Evolution Due to Tides on Evolving Stars

    Science.gov (United States)

    Penev, Kaloyan; Zhang, Michael; Jackson, Brian

    2014-06-01

    We make publicly available an efficient, versatile, easy to use and extend tool for calculating the evolution of circular aligned planetary orbits due to the tidal dissipation in the host star. This is the first model to fully account for the evolution of the angular momentum of the stellar convective envelope by the tidal coupling, the transfer of angular momentum between the stellar convective and radiative zones, the effects of the stellar evolution on the tidal dissipation efficiency and stellar core and envelope spins, the loss of stellar convective zone angular momentum to a magnetically launched wind and frequency dependent tidal dissipation. This is only a first release and further development is under way to allow calculating the evolution of inclined and eccentric orbits, with the latter including the tidal dissipation in the planet and its feedback on planetary structure. Considerable effort has been devoted to providing extensive documentation detailing both the usage and the complete implementation details, in order to make it as easy as possible for independent groups to use and/or extend the code for their purposes. POET represents a significant improvement over some previous models for planetary tidal evolution and so has many astrophysical applications. In this article, we describe and illustrate several key examples.

  7. Markov Chain-Like Quantum Biological Modeling of Mutations, Aging, and Evolution

    Directory of Open Access Journals (Sweden)

    Ivan B. Djordjevic

    2015-08-01

    Full Text Available Recent evidence suggests that quantum mechanics is relevant in photosynthesis, magnetoreception, enzymatic catalytic reactions, olfactory reception, photoreception, genetics, electron-transfer in proteins, and evolution; to mention few. In our recent paper published in Life, we have derived the operator-sum representation of a biological channel based on codon basekets, and determined the quantum channel model suitable for study of the quantum biological channel capacity. However, this model is essentially memoryless and it is not able to properly model the propagation of mutation errors in time, the process of aging, and evolution of genetic information through generations. To solve for these problems, we propose novel quantum mechanical models to accurately describe the process of creation spontaneous, induced, and adaptive mutations and their propagation in time. Different biological channel models with memory, proposed in this paper, include: (i Markovian classical model, (ii Markovian-like quantum model, and (iii hybrid quantum-classical model. We then apply these models in a study of aging and evolution of quantum biological channel capacity through generations. We also discuss key differences of these models with respect to a multilevel symmetric channel-based Markovian model and a Kimura model-based Markovian process. These models are quite general and applicable to many open problems in biology, not only biological channel capacity, which is the main focus of the paper. We will show that the famous quantum Master equation approach, commonly used to describe different biological processes, is just the first-order approximation of the proposed quantum Markov chain-like model, when the observation interval tends to zero. One of the important implications of this model is that the aging phenotype becomes determined by different underlying transition probabilities in both programmed and random (damage Markov chain-like models of aging, which

  8. Cosmological evolution in a two-brane warped geometry model

    Directory of Open Access Journals (Sweden)

    Sumit Kumar

    2015-07-01

    Full Text Available We study an effective 4-dimensional scalar–tensor field theory, originated from an underlying brane–bulk warped geometry, to explore the scenario of inflation. It is shown that the inflaton potential naturally emerges from the radion energy–momentum tensor which in turn results in an inflationary model of the Universe on the visible brane that is consistent with the recent results from the Planck's experiment. The dynamics of modulus stabilization from the inflaton rolling condition is demonstrated. The implications of our results in the context of recent BICEP2 results are also discussed.

  9. Effective dark energy equation of state in interacting dark energy models

    Energy Technology Data Exchange (ETDEWEB)

    Avelino, P.P., E-mail: ppavelin@fc.up.pt [Centro de Astrofisica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Departamento de Fisica e Astronomia da Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Silva, H.M.R. da, E-mail: hilberto.silva@gmail.com [Departamento de Fisica e Astronomia da Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal)

    2012-07-24

    In models where dark matter and dark energy interact non-minimally, the total amount of matter in a fixed comoving volume may vary from the time of recombination to the present time due to energy transfer between the two components. This implies that, in interacting dark energy models, the fractional matter density estimated using the cosmic microwave background assuming no interaction between dark matter and dark energy will in general be shifted with respect to its true value. This may result in an incorrect determination of the equation of state of dark energy if the interaction between dark matter and dark energy is not properly accounted for, even if the evolution of the Hubble parameter as a function of redshift is known with arbitrary precision. In this Letter we find an exact expression, as well as a simple analytical approximation, for the evolution of the effective equation of state of dark energy, assuming that the energy transfer rate between dark matter and dark energy is described by a simple two-parameter model. We also provide analytical examples where non-phantom interacting dark energy models mimic the background evolution and primary cosmic microwave background anisotropies of phantom dark energy models.

  10. Effective dark energy equation of state in interacting dark energy models

    International Nuclear Information System (INIS)

    Avelino, P.P.; Silva, H.M.R. da

    2012-01-01

    In models where dark matter and dark energy interact non-minimally, the total amount of matter in a fixed comoving volume may vary from the time of recombination to the present time due to energy transfer between the two components. This implies that, in interacting dark energy models, the fractional matter density estimated using the cosmic microwave background assuming no interaction between dark matter and dark energy will in general be shifted with respect to its true value. This may result in an incorrect determination of the equation of state of dark energy if the interaction between dark matter and dark energy is not properly accounted for, even if the evolution of the Hubble parameter as a function of redshift is known with arbitrary precision. In this Letter we find an exact expression, as well as a simple analytical approximation, for the evolution of the effective equation of state of dark energy, assuming that the energy transfer rate between dark matter and dark energy is described by a simple two-parameter model. We also provide analytical examples where non-phantom interacting dark energy models mimic the background evolution and primary cosmic microwave background anisotropies of phantom dark energy models.

  11. Microstructure evolution during homogenization of Al–Mn–Fe–Si alloys: Modeling and experimental results

    International Nuclear Information System (INIS)

    Du, Q.; Poole, W.J.; Wells, M.A.; Parson, N.C.

    2013-01-01

    Microstructure evolution during the homogenization heat treatment of Al–Mn–Fe–Si, or AA3xxx, alloys has been investigated using a combination of modeling and experimental studies. The model is fully coupled to CALculation PHAse Diagram (CALPHAD) software and has explicitly taken into account the two different length scales for diffusion encountered in modeling the homogenization process. The model is able to predict the evolution of all the important microstructural features during homogenization, including the inhomogeneous spatial distribution of dispersoids and alloying elements in solution, the dispersoid number density and the size distribution, and the type and fraction of intergranular constituent particles. Experiments were conducted using four direct chill (DC) cast AA3xxx alloys subjected to various homogenization treatments. The resulting microstructures were then characterized using a range of characterization techniques, including optical and electron microscopy, electron micro probe analysis, field emission gun scanning electron microscopy, and electrical resistivity measurements. The model predictions have been compared with the experimental measurements to validate the model. Further, it has been demonstrated that the validated model is able to predict the effects of alloying elements (e.g. Si and Mn) on microstructure evolution. It is concluded that the model provides a time and cost effective tool in optimizing and designing industrial AA3xxx alloy chemistries and homogenization heat treatments

  12. Modeling the evolution of channel shape: Balancing computational efficiency with hydraulic fidelity

    Science.gov (United States)

    Wobus, C.W.; Kean, J.W.; Tucker, G.E.; Anderson, R. Scott

    2008-01-01

    The cross-sectional shape of a natural river channel controls the capacity of the system to carry water off a landscape, to convey sediment derived from hillslopes, and to erode its bed and banks. Numerical models that describe the response of a landscape to changes in climate or tectonics therefore require formulations that can accommodate evolution of channel cross-sectional geometry. However, fully two-dimensional (2-D) flow models are too computationally expensive to implement in large-scale landscape evolution models, while available simple empirical relationships between width and discharge do not adequately capture the dynamics of channel adjustment. We have developed a simplified 2-D numerical model of channel evolution in a cohesive, detachment-limited substrate subject to steady, unidirectional flow. Erosion is assumed to be proportional to boundary shear stress, which is calculated using an approximation of the flow field in which log-velocity profiles are assumed to apply along vectors that are perpendicular to the local channel bed. Model predictions of the velocity structure, peak boundary shear stress, and equilibrium channel shape compare well with predictions of a more sophisticated but more computationally demanding ray-isovel model. For example, the mean velocities computed by the two models are consistent to within ???3%, and the predicted peak shear stress is consistent to within ???7%. Furthermore, the shear stress distributions predicted by our model compare favorably with available laboratory measurements for prescribed channel shapes. A modification to our simplified code in which the flow includes a high-velocity core allows the model to be extended to estimate shear stress distributions in channels with large width-to-depth ratios. Our model is efficient enough to incorporate into large-scale landscape evolution codes and can be used to examine how channels adjust both cross-sectional shape and slope in response to tectonic and climatic

  13. Technical know-how for the investigation and modelling of topographic evolution for site characterisation - 59171

    International Nuclear Information System (INIS)

    Doke, Ryosuke; Yasue, Ken-ichi; Niizato, Tadafumi; Nakayasu, Akio

    2012-01-01

    Geological hazard assessments are being used to make important decisions relevant to nuclear facilities such as a repository for deep geological disposal of high-level radioactive waste. With respect to such repositories, topographic evolution is a key issue for description of the long-term evolution of a groundwater flow characteristics in time spans of tens to hundreds of thousands of years. The construction of topographic evolution models is complex, involving tacit knowledge and working processes. Therefore, it is important to externalise, that is to explicitly present the tacit knowledge and decision-making processes used by experts in the model building unambiguously, with thorough documentation and to provide key knowledge to support planning and implementation of investigations. In this study, documentation of the technical know-how used for the construction of a topographic evolution model is demonstrated. The process followed in the construction of the model is illustrated using task-flow logic diagrams; the process involves four main tasks with several sub-tasks. The task-flow followed for an investigation to estimate uplift rates linked to the task-flow for the modelling of topographic evolution is also illustrated. In addition, the decision-making processes in the investigation are expressed in logical IF-THEN format for each task. Based on the documented technical know-how, an IT-based Expert System was constructed. In future work, it is necessary to analyse the knowledge, including the management of uncertainties in the modelling and investigations, and to integrate fundamental ideas for managing uncertainties with expert system. (authors)

  14. Modeling property evolution of container materials used in nuclear waste storage

    Science.gov (United States)

    Li, Dongsheng; Garmestani, Hamid; Khaleel, Moe; Sun, Xin

    2010-03-01

    Container materials under irradiation for a long time will raise high energy in the structure to generate critical structural damage. This study investigated what kind of mesoscale microstructure will be more resistant to radiation damage. Mechanical properties evolution during irradiation was modeled using statistical continuum mechanics. Preliminary results also showed how to achieve the desired microstructure with higher resistance to radiation.

  15. A Double Zone Dynamical Model For The Tidal Evolution Of The Obliquity

    Science.gov (United States)

    Damiani, Cilia

    2017-10-01

    It is debated wether close-in giants planets can form in-situ and if not, which mechanisms are responsible for their migration. One of the observable tests for migration theories is the current value of the obliquity. But after the main migration mechanism has ended, the combined effects of tidal dissipation and the magnetic braking of the star lead to the evolution of both the obliquity and the semi-major axis. The observed correlation between effective temperature and measured projected obliquity has been taken as evidence of such mechanisms being at play. Here I present an improved model for the tidal evolution of the obliquity. It includes all the components of the dynamical tide for circular misaligned systems. It uses an analytical formulation for the frequency-averaged dissipation for each mode, depending only on global stellar parameters, giving a measure of the dissipative properties of the convective zone of the host as it evolves in time. The model also includes the effect of magnetic braking in the framework of the double zone model. This results in the estimation of different tidal evolution timescales for the evolution of the planet's semi-major axis and obliquity depending on the properties of the stellar host. This model can be used to test migration theories, provided that a good determination of stellar radii, masses and ages can be obtained.

  16. A theoretical model of the evolution of maternal effects under parent-offspring conflict

    NARCIS (Netherlands)

    Uller, Tobias; Pen, Ido

    The evolution of maternal effects on offspring phenotype should depend on the extent of parent-offspring conflict and costs and constraints associated with maternal and offspring strategies. Here, we develop a model of maternal effects on offspring dispersal phenotype under parent-offspring conflict

  17. User Acceptance of Long-Term Evolution (LTE) Services: An Application of Extended Technology Acceptance Model

    Science.gov (United States)

    Park, Eunil; Kim, Ki Joon

    2013-01-01

    Purpose: The aim of this paper is to propose an integrated path model in order to explore user acceptance of long-term evolution (LTE) services by examining potential causal relationships between key psychological factors and user intention to use the services. Design/methodology/approach: Online survey data collected from 1,344 users are analysed…

  18. Investigating Island Evolution: A Galapagos-Based Lesson Using the 5E Instructional Model.

    Science.gov (United States)

    DeFina, Anthony V.

    2002-01-01

    Introduces an inquiry-based lesson plan on evolution and the Galapagos Islands. Uses the 5E instructional model which includes phases of engagement, exploration, explanation, elaboration, and evaluation. Includes information on species for exploration and elaboration purposes, and a general rubric for student evaluation. (YDS)

  19. Recurrence relations and time evolution in the three-dimensional Sawada model

    International Nuclear Information System (INIS)

    Lee, M.H.; Hong, J.

    1984-01-01

    Time-dependent behavior of the three-dimensional Sawada model is obtained by a method of recurrence relations. Exactly calculated quantities are the time evolution of the density-fluctuation operator and its random force. As an application, their linear coefficients, the relaxation and memory functions are used to obtain certain dynamic quantities, e.g., the mobility

  20. Evolution of a neutral-ion 2 fluid system using thermal lattice Boltzmann model

    International Nuclear Information System (INIS)

    Vahala, L.; Vahala, G.; Carter, J.; Pavlo, P.

    2000-01-01

    The 2D evolution of a 2-species system is examined using the thermal lattice Boltzmann model (TLBM). The effects of velocity shear layers on sharp heat fronts are considered for a neutral-ion system in the case where both species are turbulent. The rate at which the species velocities and temperatures equilibrate no longer follow the Morse estimate. (author)