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Sample records for n-vector model collective

  1. A minimal model for SU( N ) vector dark matter

    NASA Astrophysics Data System (ADS)

    Di Chiara, Stefano; Tuominen, Kimmo

    2015-11-01

    We study an extension of the Standard Model featuring a hidden sector that consists of a new scalar charged under a new SU( N ) D gauge group , singlet under all Standard Model gauge interactions, and coupled with the Standard Model only via a Higgs portal. We assume that the theory is classically conformal, with electroweak symmetry breaking dynamically induced via the Coleman-Weinberg mechanism operating in the hidden sector. Due to the symmetry breaking pattern, the SU( N ) D gauge group is completely Higgsed and the resulting massive vectors of the hidden sector constitute a stable dark matter candidate. We perform a thorough scan over the parameter space of the model at different values of N = 2, 3, and 4, and investigate the phenomenological constraints. We find that N = 2 , 3 provide the most appealing model setting in light of present data from colliders and dark matter direct search experiments. We expect a heavy Higgs to be discovered at LHC by the end of Run II or the N = 3 model to be ruled out.

  2. Entanglement and RG in the O( N ) vector model

    NASA Astrophysics Data System (ADS)

    Akers, Chris; Ben-Ami, Omer; Rosenhaus, Vladimir; Smolkin, Michael; Yankielowicz, Shimon

    2016-03-01

    We consider the large N interacting vector O( N ) model on a sphere in 4 - ɛ Euclidean dimensions. The Gaussian theory in the UV is taken to be either conformally or non-conformally coupled. The endpoint of the RG flow corresponds to a conformally coupled scalar field at the Wilson-Fisher fixed point. We take a spherical entangling surface in de Sitter space and compute the entanglement entropy everywhere along the RG trajectory. In 4 dimensions, a free non-conformal scalar has a universal area term scaling with the logarithm of the UV cutoff. In 4 - ɛ dimensions, such a term scales as 1 /ɛ. For a non-conformal scalar, a 1 /ɛ term is present both at the UV fixed point, and its vicinity. For flow between two conformal fixed points, 1 /ɛ terms are absent everywhere. Finally, we make contact with replica trick calculations. The conical singularity gives rise to boundary terms residing on the entangling surface, which are usually discarded. Consistency with our results requires they be kept. We argue that, in fact, this conclusion also follows from the work of Metlitski, Fuertes, and Sachdev, which demonstrated that such boundary terms will be generated through quantum corrections.

  3. Low Temperature Properties for Correlation Functions in Classical N-Vector Spin Models

    NASA Astrophysics Data System (ADS)

    Balaban, Tadeusz; O'Carroll, Michael

    We obtain convergent multi-scale expansions for the one-and two-point correlation functions of the low temperature lattice classical N- vector spin model in d>= 3 dimensions, N>= 2. The Gibbs factor is taken as where , , , are large and 0 < v<= 1. In the thermodynamic and limits, with h=e1, and Δ≡∂*∂, the expansion gives (spontaneous magnetization), , (Goldstone Bosons), , and , where , for some ρ > 0, and c0 is aprecisely determined constant.

  4. S = 1 in free O(N) vector model/HS duality

    NASA Astrophysics Data System (ADS)

    de Mello Koch, Robert; Jevicki, Antal; Jin, Kewang; Rodrigues, João P.; Ye, Qibin

    2013-05-01

    Following the work of Maldacena and Zhiboedov, we study the implementation of the Coleman-Mandula theorem in the free O(N)/higher spin correspondence. In the bi-local framework we first define an S-matrix for scattering of collective dipoles. Its evaluation in the case of free UV fixed point theory leads to the result S = 1 stated in the title. We also present an appropriate field transformation that is seen to transform away all the nonlinear 1/N interactions of this theory. A change of boundary conditions and/or external potentials results in a nontrivial theory.

  5. Towards a fully automated computation of RG functions for the three-dimensional O(N) vector model: parametrizing amplitudes

    NASA Astrophysics Data System (ADS)

    Guida, Riccardo; Ribeca, Paolo

    2006-02-01

    Within the framework of field-theoretical description of second-order phase transitions via the three-dimensional O(N) vector model, accurate predictions for critical exponents can be obtained from (resummation of) the perturbative series of renormalization-group functions, which are in turn derived—following Parisi's approach—from the expansions of appropriate field correlators evaluated at zero external momenta. Such a technique was fully exploited 30 years ago in two seminal works of Baker, Nickel, Green and Meiron, which led to the knowledge of the β-function up to the six-loop level; they succeeded in obtaining a precise numerical evaluation of all needed Feynman amplitudes in momentum space by lowering the dimensionalities of each integration with a cleverly arranged set of computational simplifications. In fact, extending this computation is not straightforward, due both to the factorial proliferation of relevant diagrams and the increasing dimensionality of their associated integrals; in any case, this task can be reasonably carried on only in the framework of an automated environment. On the road towards the creation of such an environment, we here show how a strategy closely inspired by that of Nickel and co-workers can be stated in algorithmic form, and successfully implemented on a computer. As an application, we plot the minimized distributions of residual integrations for the sets of diagrams needed to obtain RG functions to the full seven-loop level; they represent a good evaluation of the computational effort which will be required to improve the currently available estimates of critical exponents.

  6. Off-equilibrium scaling behaviors driven by time-dependent external fields in three-dimensional O(N) vector models.

    PubMed

    Pelissetto, Andrea; Vicari, Ettore

    2016-03-01

    We consider the dynamical off-equilibrium behavior of the three-dimensional O(N) vector model in the presence of a slowly varying time-dependent spatially uniform magnetic field H(t)=h(t)e, where e is an N-dimensional constant unit vector, h(t)=t/t(s), and t(s) is a time scale, at fixed temperature T≤T(c), where T(c) corresponds to the continuous order-disorder transition. The dynamic evolutions start from equilibrium configurations at h(i)<0, correspondingly t(i)<0, and end at time t(f)>0 with h(t(f))>0, or vice versa. We show that the magnetization displays an off-equilibrium scaling behavior close to the transition line H(t)=0. It arises from the interplay among the time t, the time scale t(s), and the finite size L. The scaling behavior can be parametrized in terms of the scaling variables t(s)(κ)/L and t/t(s)(κ(t)), where κ>0 and κ(t)>0 are appropriate universal exponents, which differ at the critical point and for Tmodel under a purely relaxational dynamics. They confirm the predicted off-equilibrium scaling behaviors at and below T(c). We also discuss hysteresis phenomena in round-trip protocols for the time dependence of the external field. We define a scaling function for the hysteresis loop area of the magnetization that can be used to quantify how far the system is from equilibrium. PMID:27078326

  7. Off-equilibrium scaling behaviors driven by time-dependent external fields in three-dimensional O(N) vector models.

    PubMed

    Pelissetto, Andrea; Vicari, Ettore

    2016-03-01

    We consider the dynamical off-equilibrium behavior of the three-dimensional O(N) vector model in the presence of a slowly varying time-dependent spatially uniform magnetic field H(t)=h(t)e, where e is an N-dimensional constant unit vector, h(t)=t/t(s), and t(s) is a time scale, at fixed temperature T≤T(c), where T(c) corresponds to the continuous order-disorder transition. The dynamic evolutions start from equilibrium configurations at h(i)<0, correspondingly t(i)<0, and end at time t(f)>0 with h(t(f))>0, or vice versa. We show that the magnetization displays an off-equilibrium scaling behavior close to the transition line H(t)=0. It arises from the interplay among the time t, the time scale t(s), and the finite size L. The scaling behavior can be parametrized in terms of the scaling variables t(s)(κ)/L and t/t(s)(κ(t)), where κ>0 and κ(t)>0 are appropriate universal exponents, which differ at the critical point and for Tmodel under a purely relaxational dynamics. They confirm the predicted off-equilibrium scaling behaviors at and below T(c). We also discuss hysteresis phenomena in round-trip protocols for the time dependence of the external field. We define a scaling function for the hysteresis loop area of the magnetization that can be used to quantify how far the system is from equilibrium.

  8. Photon-induced neutron polarization from the {sup 2}H({gamma},n-vector){sup 1}H reaction within the NN-force model with an intermediate dibaryon

    SciTech Connect

    Kukulin, V. I.; Obukhovsky, I. T.; Pomerantsev, V. N.; Faessler, Amand; Grabmayr, Peter

    2008-04-15

    A model for the NN force, which is induced by the formation of an intermediate dibaryon dressed with {sigma}- and other meson fields, has been developed by the present authors in previous years. This model is applied to the deuteron photodisintegration processes with the main focus on the {gamma}-induced polarization P{sub y}{sup '} of the neutron at energies below E{sub {gamma}} < or approx. 30 MeV. The inclusion of the intermediate dibaryon leads to a model of the NN force completely different to the conventional NN potential models at short distances. Here the model is tested on the nucleonic level through comparison to rather similar predictions from the conventional NN potential model both for the total and differential cross sections and also for the spin polarization of the ejected neutrons. The predictions of the present model are at least of the same quality than those for the Nijmegen potential; the visible differences with experimental data for P{sub y}{sup '} still remain. However, in combination with the previous results a consistent description can be achieved simultaneously for many observables.

  9. Modeling collective cell motility

    NASA Astrophysics Data System (ADS)

    Rappel, Wouter-Jan

    Eukaryotic cells often move in groups, a critical aspect of many biological and medical processes including wound healing, morphogenesis and cancer metastasis. Modeling can provide useful insights into the fundamental mechanisms of collective cell motility. Constructing models that incorporate the physical properties of the cells, however, is challenging. Here, I discuss our efforts to build a comprehensive cell motility model that includes cell membrane properties, cell-substrate interactions, cell polarity, and cell-cell interaction. The model will be applied to a variety of systems, including motion on micropatterned substrates and the migration of border cells in Drosophila. This work was supported by NIH Grant No. P01 GM078586 and NSF Grant No. 1068869.

  10. Neurodynamical model of collective brain

    NASA Technical Reports Server (NTRS)

    Zak, Michail

    1992-01-01

    A dynamical system which mimics collective purposeful activities of a set of units of intelligence is introduced and discussed. A global control of the unit activities is replaced by the probabilistic correlations between them. These correlations are learned during a long term period of performing collective tasks, and are stored in the synaptic interconnections. The model is represented by a system of ordinary differential equations with terminal attractors and repellers, and does not contain any man-made digital devices.

  11. Bohr model as an algebraic collective model

    SciTech Connect

    Rowe, D. J.; Welsh, T. A.; Caprio, M. A.

    2009-05-15

    Developments and applications are presented of an algebraic version of Bohr's collective model. Illustrative examples show that fully converged calculations can be performed quickly and easily for a large range of Hamiltonians. As a result, the Bohr model becomes an effective tool in the analysis of experimental data. The examples are chosen both to confirm the reliability of the algebraic collective model and to show the diversity of results that can be obtained by its use. The focus of the paper is to facilitate identification of the limitations of the Bohr model with a view to developing more realistic, computationally tractable models.

  12. Modeling Charge Collection in Detector Arrays

    NASA Technical Reports Server (NTRS)

    Hardage, Donna (Technical Monitor); Pickel, J. C.

    2003-01-01

    A detector array charge collection model has been developed for use as an engineering tool to aid in the design of optical sensor missions for operation in the space radiation environment. This model is an enhancement of the prototype array charge collection model that was developed for the Next Generation Space Telescope (NGST) program. The primary enhancements were accounting for drift-assisted diffusion by Monte Carlo modeling techniques and implementing the modeling approaches in a windows-based code. The modeling is concerned with integrated charge collection within discrete pixels in the focal plane array (FPA), with high fidelity spatial resolution. It is applicable to all detector geometries including monolithc charge coupled devices (CCDs), Active Pixel Sensors (APS) and hybrid FPA geometries based on a detector array bump-bonded to a readout integrated circuit (ROIC).

  13. Modelling fuel consumption in kerbside source segregated food waste collection: separate collection and co-collection.

    PubMed

    Chu, T W; Heaven, S; Gredmaier, L

    2015-01-01

    Source separated food waste is a valuable feedstock for renewable energy production through anaerobic digestion, and a variety of collection schemes for this material have recently been introduced. The aim of this study was to identify options that maximize collection efficiency and reduce fuel consumption as part of the overall energy balance. A mechanistic model was developed to calculate the fuel consumption of kerbside collection of source segregated food waste, co-mingled dry recyclables and residual waste. A hypothetical city of 20,000 households was considered and nine scenarios were tested with different combinations of collection frequencies, vehicle types and waste types. The results showed that the potential fuel savings from weekly and fortnightly co-collection of household waste range from 7.4% to 22.4% and 1.8% to 26.6%, respectively, when compared to separate collection. A compartmentalized vehicle split 30:70 always performed better than one with two compartments of equal size. Weekly food waste collection with alternate weekly collection of the recyclables and residual waste by two-compartment collection vehicles was the best option to reduce the overall fuel consumption.

  14. Locust Collective Motion and Its Modeling.

    PubMed

    Ariel, Gil; Ayali, Amir

    2015-12-01

    Over the past decade, technological advances in experimental and animal tracking techniques have motivated a renewed theoretical interest in animal collective motion and, in particular, locust swarming. This review offers a comprehensive biological background followed by comparative analysis of recent models of locust collective motion, in particular locust marching, their settings, and underlying assumptions. We describe a wide range of recent modeling and simulation approaches, from discrete agent-based models of self-propelled particles to continuous models of integro-differential equations, aimed at describing and analyzing the fascinating phenomenon of locust collective motion. These modeling efforts have a dual role: The first views locusts as a quintessential example of animal collective motion. As such, they aim at abstraction and coarse-graining, often utilizing the tools of statistical physics. The second, which originates from a more biological perspective, views locust swarming as a scientific problem of its own exceptional merit. The main goal should, thus, be the analysis and prediction of natural swarm dynamics. We discuss the properties of swarm dynamics using the tools of statistical physics, as well as the implications for laboratory experiments and natural swarms. Finally, we stress the importance of a combined-interdisciplinary, biological-theoretical effort in successfully confronting the challenges that locusts pose at both the theoretical and practical levels. PMID:26656851

  15. Locust Collective Motion and Its Modeling

    PubMed Central

    Ariel, Gil; Ayali, Amir

    2015-01-01

    Over the past decade, technological advances in experimental and animal tracking techniques have motivated a renewed theoretical interest in animal collective motion and, in particular, locust swarming. This review offers a comprehensive biological background followed by comparative analysis of recent models of locust collective motion, in particular locust marching, their settings, and underlying assumptions. We describe a wide range of recent modeling and simulation approaches, from discrete agent-based models of self-propelled particles to continuous models of integro-differential equations, aimed at describing and analyzing the fascinating phenomenon of locust collective motion. These modeling efforts have a dual role: The first views locusts as a quintessential example of animal collective motion. As such, they aim at abstraction and coarse-graining, often utilizing the tools of statistical physics. The second, which originates from a more biological perspective, views locust swarming as a scientific problem of its own exceptional merit. The main goal should, thus, be the analysis and prediction of natural swarm dynamics. We discuss the properties of swarm dynamics using the tools of statistical physics, as well as the implications for laboratory experiments and natural swarms. Finally, we stress the importance of a combined-interdisciplinary, biological-theoretical effort in successfully confronting the challenges that locusts pose at both the theoretical and practical levels. PMID:26656851

  16. Locust Collective Motion and Its Modeling.

    PubMed

    Ariel, Gil; Ayali, Amir

    2015-12-01

    Over the past decade, technological advances in experimental and animal tracking techniques have motivated a renewed theoretical interest in animal collective motion and, in particular, locust swarming. This review offers a comprehensive biological background followed by comparative analysis of recent models of locust collective motion, in particular locust marching, their settings, and underlying assumptions. We describe a wide range of recent modeling and simulation approaches, from discrete agent-based models of self-propelled particles to continuous models of integro-differential equations, aimed at describing and analyzing the fascinating phenomenon of locust collective motion. These modeling efforts have a dual role: The first views locusts as a quintessential example of animal collective motion. As such, they aim at abstraction and coarse-graining, often utilizing the tools of statistical physics. The second, which originates from a more biological perspective, views locust swarming as a scientific problem of its own exceptional merit. The main goal should, thus, be the analysis and prediction of natural swarm dynamics. We discuss the properties of swarm dynamics using the tools of statistical physics, as well as the implications for laboratory experiments and natural swarms. Finally, we stress the importance of a combined-interdisciplinary, biological-theoretical effort in successfully confronting the challenges that locusts pose at both the theoretical and practical levels.

  17. Generalized cranking model for collective nuclear motion

    NASA Astrophysics Data System (ADS)

    Kunz, J.; Nix, J. R.

    1984-09-01

    The Inglis cranking model is generalized to take into account effects of any velocity dependence present in the single-particle potential and the reaction of the pairing field to the collective motion. The generalized model is applied to translations, rotations and some special types of vibrations. Some of our results and our numerical calculations are obtained with a harmonic-oscillator single-particle potential. Unlike the inertia calculated with the Inglis cranking model, the inertia calculated with the generalized cranking model is independent of the effective mass and approaches the irrotational value in the limit of large pairing.

  18. The modelling cycle for collective animal behaviour

    PubMed Central

    Sumpter, David J. T.; Mann, Richard P.; Perna, Andrea

    2012-01-01

    Collective animal behaviour is the study of how interactions between individuals produce group level patterns, and why these interactions have evolved. This study has proved itself uniquely interdisciplinary, involving physicists, mathematicians, engineers as well as biologists. Almost all experimental work in this area is related directly or indirectly to mathematical models, with regular movement back and forth between models, experimental data and statistical fitting. In this paper, we describe how the modelling cycle works in the study of collective animal behaviour. We classify studies as addressing questions at different levels or linking different levels, i.e. as local, local to global, global to local or global. We also describe three distinct approaches—theory-driven, data-driven and model selection—to these questions. We show, with reference to our own research on species across different taxa, how we move between these different levels of description and how these various approaches can be applied to link levels together. PMID:23173077

  19. Developing New Models for Collection Development.

    ERIC Educational Resources Information Center

    Stoffle, Carla J.; Fore, Janet; Allen, Barbara

    1999-01-01

    Discusses the need to develop new models for collection development in academic libraries, based on experiences at the University of Arizona. Highlights include changes in the organizational chart; focusing on users' information goals and needs; integrative services; shared resources; interlibrary loans; digital technology; and funding. (LRW)

  20. Relating ground truth collection to model sensitivity

    NASA Technical Reports Server (NTRS)

    Amar, Faouzi; Fung, Adrian K.; Karam, Mostafa A.; Mougin, Eric

    1993-01-01

    The importance of collecting high quality ground truth before a SAR mission over a forested area is two fold. First, the ground truth is used in the analysis and interpretation of the measured backscattering properties; second, it helps to justify the use of a scattering model to fit the measurements. Unfortunately, ground truth is often collected based on visual assessment of what is perceived to be important without regard to the mission itself. Sites are selected based on brief surveys of large areas, and the ground truth is collected by a process of selecting and grouping different scatterers. After the fact, it may turn out that some of the relevant parameters are missing. A three-layer canopy model based on the radiative transfer equations is used to determine, before hand, the relevant parameters to be collected. Detailed analysis of the contribution to scattering and attenuation of various forest components is carried out. The goal is to identify the forest parameters which most influence the backscattering as a function of frequency (P-, L-, and C-bands) and incident angle. The influence on backscattering and attenuation of branch diameters, lengths, angular distribution, and permittivity; trunk diameters, lengths, and permittivity; and needle sizes, their angular distribution, and permittivity are studied in order to maximize the efficiency of the ground truth collection efforts. Preliminary results indicate that while a scatterer may not contribute to the total backscattering, its contribution to attenuation may be significant depending on the frequency.

  1. Adaptive-network models of collective dynamics

    NASA Astrophysics Data System (ADS)

    Zschaler, G.

    2012-09-01

    Complex systems can often be modelled as networks, in which their basic units are represented by abstract nodes and the interactions among them by abstract links. This network of interactions is the key to understanding emergent collective phenomena in such systems. In most cases, it is an adaptive network, which is defined by a feedback loop between the local dynamics of the individual units and the dynamical changes of the network structure itself. This feedback loop gives rise to many novel phenomena. Adaptive networks are a promising concept for the investigation of collective phenomena in different systems. However, they also present a challenge to existing modelling approaches and analytical descriptions due to the tight coupling between local and topological degrees of freedom. In this work, which is essentially my PhD thesis, I present a simple rule-based framework for the investigation of adaptive networks, using which a wide range of collective phenomena can be modelled and analysed from a common perspective. In this framework, a microscopic model is defined by the local interaction rules of small network motifs, which can be implemented in stochastic simulations straightforwardly. Moreover, an approximate emergent-level description in terms of macroscopic variables can be derived from the microscopic rules, which we use to analyse the system's collective and long-term behaviour by applying tools from dynamical systems theory. We discuss three adaptive-network models for different collective phenomena within our common framework. First, we propose a novel approach to collective motion in insect swarms, in which we consider the insects' adaptive interaction network instead of explicitly tracking their positions and velocities. We capture the experimentally observed onset of collective motion qualitatively in terms of a bifurcation in this non-spatial model. We find that three-body interactions are an essential ingredient for collective motion to emerge

  2. Connexions for the nuclear geometrical collective model

    NASA Astrophysics Data System (ADS)

    Rosensteel, G.; Sparks, N.

    2015-11-01

    The Bohr-Mottelson-Frankfurt model of nuclear rotations and quadrupole vibrations is a foundational model in nuclear structure physics. The model, also called the geometrical collective model or simply GCM(3), has two hidden mathematical structures, one group theoretic and the other differential geometric. Although the group structure has been understood for some time, the geometric structure is a new feature that this paper investigates in some detail. Using the de Rham Laplacian \\triangle =\\star d \\star d for the kinetic energy extends significantly the physical scope of the GCM(3) model. This Laplacian contains a ‘magnetic’ term due to the connexion between base manifold rotational and fibre vortex degrees of freedom. When the connexion specializes to irrotational flow, the Laplacian reduces to the Bohr-Mottelson kinetic energy operator.

  3. Model of electron collecting plasma contactors

    SciTech Connect

    Davis, V.A.; Katz, I.; Mandell, M.J.; Parks, D.E. )

    1991-06-01

    In laboratory experiments, plasma contactors are observed to collect ampere-level electron currents with low impedance. In order to extend the laboratory experience to the low-earth-orbit environment, a model of plasma contactors is being developed. Laboratory results are being used to support and validate the model development. The important physical processes observed in the laboratory are that the source plasma is separated from the background plasma by a double layer and that ionization of the expellant gas by the collected electrons creates the bulk of the ions that leave the source plasma. The model, which uses Poisson's equation with a physical charge density that includes the ion and electron components of both the source and the ambient plasmas, reproduces this phenomenon for typical experimental parameters. The calculations, in agreement with the laboratory results, show little convergence of the accelerated electrons. The angular momentum of the incoming electrons dramatically reduces the peak electron density. These electrons ionize enough gas to generate the source plasma. Calculations show that the increase in ionization rate with potential produces a steep rise in collected current with increasing potential as seen in the laboratory. 26 refs.

  4. A statistical model for collective risk assessment

    NASA Astrophysics Data System (ADS)

    Keef, Caroline; Tawn, Jonathan A.; Lamb, Rob

    2010-05-01

    In this paper we present the theoretical basis of a statistical method that can be used as the basis of a collective risk assessment for country (or continent)-wide events. Our method is based on the conditional dependence model of Heffernan and Tawn (2004), which has been extended to handle missing data and temporal dependence by Keef et al (2009). This model describes the full joint distribution function of a set of variables and incorporates separate models for the marginal and dependence characteristics of the set using a copula approach. The advantages of this model include; the flexibility in terms of types of dependence modelled; the ability to handle situations where the dependence in the tails of the data is not the same as that in the main body of the data; the ability to handle both temporal and spatial dependence; and the ability to model a large number of variables. In this paper we present further extensions to the statistical model which allow us to simulate country-wide extreme events with the correct spatial and temporal structure and show an application to river flood events. Heffernan J. E. and Tawn J. A. (2004) A conditional approach for multivariate extreme values (with discussion) J. R. Statist. Soc. B, 66 497-546 Keef, C., J. Tawn, and C. Svensson. (2009). Spatial risk assessment for extreme river flows. Applied Statistics 58,(5) pp 601-618

  5. On conviction's collective consequences: integrating moral conviction with the social identity model of collective action.

    PubMed

    van Zomeren, Martijn; Postmes, Tom; Spears, Russell

    2012-03-01

    This article examines whether and how moral convictions predict collective action to achieve social change. Because moral convictions - defined as strong and absolute stances on moral issues - tolerate no exceptions, any violation motivates individuals to actively change that situation. We propose that moral convictions have a special relationship with politicized identities and collective action because of the potentially strong normative fit between moral convictions and the action-oriented content of politicized identities. This effectively integrates moral conviction with the Social Identity Model of Collective Action (Van Zomeren, Postmes, & Spears, 2008), which predicts that, on the basis of a relevant social identity, group-based anger and efficacy predict collective action. Results from two studies indeed showed that moral convictions predicted collective action intentions (Study 1-2) and collective action (Study 2) through politicized identification, group-based anger, and group efficacy. We discuss theoretical and practical implications of our integrative model. PMID:22435846

  6. A computationally tractable version of the collective model

    NASA Astrophysics Data System (ADS)

    Rowe, D. J.

    2004-05-01

    A computationally tractable version of the Bohr-Mottelson collective model is presented which makes it possible to diagonalize realistic collective models and obtain convergent results in relatively small appropriately chosen subspaces of the collective model Hilbert space. Special features of the proposed model are that it makes use of the beta wave functions given analytically by the softened-beta version of the Wilets-Jean model, proposed by Elliott et al., and a simple algorithm for computing SO(5)⊃SO(3) spherical harmonics. The latter has much in common with the methods of Chacon, Moshinsky, and Sharp but is conceptually and computationally simpler. Results are presented for collective models ranging from the spherical vibrator to the Wilets-Jean and axially symmetric rotor-vibrator models.

  7. Modeling crowdsourcing as collective problem solving.

    PubMed

    Guazzini, Andrea; Vilone, Daniele; Donati, Camillo; Nardi, Annalisa; Levnajić, Zoran

    2015-01-01

    Crowdsourcing is a process of accumulating the ideas, thoughts or information from many independent participants, with aim to find the best solution for a given challenge. Modern information technologies allow for massive number of subjects to be involved in a more or less spontaneous way. Still, the full potentials of crowdsourcing are yet to be reached. We introduce a modeling framework through which we study the effectiveness of crowdsourcing in relation to the level of collectivism in facing the problem. Our findings reveal an intricate relationship between the number of participants and the difficulty of the problem, indicating the optimal size of the crowdsourced group. We discuss our results in the context of modern utilization of crowdsourcing.

  8. Modeling crowdsourcing as collective problem solving.

    PubMed

    Guazzini, Andrea; Vilone, Daniele; Donati, Camillo; Nardi, Annalisa; Levnajić, Zoran

    2015-01-01

    Crowdsourcing is a process of accumulating the ideas, thoughts or information from many independent participants, with aim to find the best solution for a given challenge. Modern information technologies allow for massive number of subjects to be involved in a more or less spontaneous way. Still, the full potentials of crowdsourcing are yet to be reached. We introduce a modeling framework through which we study the effectiveness of crowdsourcing in relation to the level of collectivism in facing the problem. Our findings reveal an intricate relationship between the number of participants and the difficulty of the problem, indicating the optimal size of the crowdsourced group. We discuss our results in the context of modern utilization of crowdsourcing. PMID:26552943

  9. Modeling crowdsourcing as collective problem solving

    PubMed Central

    Guazzini, Andrea; Vilone, Daniele; Donati, Camillo; Nardi, Annalisa; Levnajić, Zoran

    2015-01-01

    Crowdsourcing is a process of accumulating the ideas, thoughts or information from many independent participants, with aim to find the best solution for a given challenge. Modern information technologies allow for massive number of subjects to be involved in a more or less spontaneous way. Still, the full potentials of crowdsourcing are yet to be reached. We introduce a modeling framework through which we study the effectiveness of crowdsourcing in relation to the level of collectivism in facing the problem. Our findings reveal an intricate relationship between the number of participants and the difficulty of the problem, indicating the optimal size of the crowdsourced group. We discuss our results in the context of modern utilization of crowdsourcing. PMID:26552943

  10. Modeling crowdsourcing as collective problem solving

    NASA Astrophysics Data System (ADS)

    Guazzini, Andrea; Vilone, Daniele; Donati, Camillo; Nardi, Annalisa; Levnajić, Zoran

    2015-11-01

    Crowdsourcing is a process of accumulating the ideas, thoughts or information from many independent participants, with aim to find the best solution for a given challenge. Modern information technologies allow for massive number of subjects to be involved in a more or less spontaneous way. Still, the full potentials of crowdsourcing are yet to be reached. We introduce a modeling framework through which we study the effectiveness of crowdsourcing in relation to the level of collectivism in facing the problem. Our findings reveal an intricate relationship between the number of participants and the difficulty of the problem, indicating the optimal size of the crowdsourced group. We discuss our results in the context of modern utilization of crowdsourcing.

  11. Modelling Rho GTPase biochemistry to predict collective cell migration

    NASA Astrophysics Data System (ADS)

    Merchant, Brian; Feng, James

    The collective migration of cells, due to individual cell polarization and intercellular contact inhibition of locomotion, features prominently in embryogenesis and metastatic cancers. Existing methods for modelling collectively migrating cells tend to rely either on highly abstracted agent-based models, or on continuum approximations of the group. Both of these frameworks represent intercellular interactions such as contact inhibition of locomotion as hard-coded rules defining model cells. In contrast, we present a vertex-dynamics framework which predicts polarization and contact inhibition of locomotion naturally from an underlying model of Rho GTPase biochemistry and cortical mechanics. We simulate the interaction between many such model cells, and study how modulating Rho GTPases affects migratory characteristics of the group, in the context of long-distance collective migration of neural crest cells during embryogenesis.

  12. Modeling and simulation of the SDC Data Collection Chip

    SciTech Connect

    Hughes, E.; Tharakan, G.; Downing, R.; Haney, M.; Golin, E.; Jones, L.; Knapp, D.; Thaler, J.

    1991-12-31

    This paper describes modeling and simulation of the Data Collection Chip (DCC) design for the Solenoidal Detector Collaboration (SDC). Models of the DCC written in Verilog and VHDL are described, and results are presented. The models have been simulated to study queue depth requirements and to compare control feedback alternatives. Insight into the management of models and simulation tools is given. Finally, techniques useful in the design process for data acquisition systems are discussed.

  13. Modeling and simulation of the SDC Data Collection Chip

    SciTech Connect

    Hughes, E.; Tharakan, G.; Downing, R.; Haney, M.; Golin, E.; Jones, L.; Knapp, D.; Thaler, J.

    1991-01-01

    This paper describes modeling and simulation of the Data Collection Chip (DCC) design for the Solenoidal Detector Collaboration (SDC). Models of the DCC written in Verilog and VHDL are described, and results are presented. The models have been simulated to study queue depth requirements and to compare control feedback alternatives. Insight into the management of models and simulation tools is given. Finally, techniques useful in the design process for data acquisition systems are discussed.

  14. Modeling and simulation of the SDC data collection chip

    SciTech Connect

    Hughes, E.; Haney, M.; Golin, E.; Jones, L.; Knapp, D.; Tharakan, G.; Downing, R. )

    1992-04-01

    This paper describes modeling and simulation of the Data Collection Chip (DCC) design for the Solenoidal Detector Collaboration (SDC). Models of the DCC written in Verilog and VHDL are described, and results are presented. The models have been simulated to study queue depth requirements and to compare control feedback alternatives. Insight into the management of models and simulation tools is given. Finally, techniques useful in the design process for data acquisition systems are discussed.

  15. A collective decision model involving vague concepts and linguistic expressions.

    PubMed

    Tang, Yongchuan

    2008-04-01

    In linguistic collective decision, the main objective is to select the best alternatives using linguistic evaluations provided by multiple experts. This paper presents a collective decision model, which is able to deal with complex linguistic evaluations. In this decision model, the linguistic evaluations are represented by linguistic expressions which are the logic formulas obtained by applying logic connectives to the set of basic linguistic labels. The vagueness of each linguistic expression is implicitly captured by a semantic similarity relation rather than a fuzzy set, since each linguistic expression determines a semantic similarity distribution on the set of basic linguistic labels. The basic idea of this collective decision model is to convert the semantic similarity distributions determined by linguistic expressions into probability distributions of the corresponding linguistic expressions. The main advantage of this proposed model is its capability to deal with complex linguistic evaluations and partial semantic overlapping among neighboring linguistic labels. PMID:18348924

  16. Satellite image collection modeling for large area hazard emergency response

    NASA Astrophysics Data System (ADS)

    Liu, Shufan; Hodgson, Michael E.

    2016-08-01

    Timely collection of critical hazard information is the key to intelligent and effective hazard emergency response decisions. Satellite remote sensing imagery provides an effective way to collect critical information. Natural hazards, however, often have large impact areas - larger than a single satellite scene. Additionally, the hazard impact area may be discontinuous, particularly in flooding or tornado hazard events. In this paper, a spatial optimization model is proposed to solve the large area satellite image acquisition planning problem in the context of hazard emergency response. In the model, a large hazard impact area is represented as multiple polygons and image collection priorities for different portion of impact area are addressed. The optimization problem is solved with an exact algorithm. Application results demonstrate that the proposed method can address the satellite image acquisition planning problem. A spatial decision support system supporting the optimization model was developed. Several examples of image acquisition problems are used to demonstrate the complexity of the problem and derive optimized solutions.

  17. Particle Swarm Based Collective Searching Model for Adaptive Environment

    SciTech Connect

    Cui, Xiaohui; Patton, Robert M; Potok, Thomas E; Treadwell, Jim N

    2008-01-01

    This report presents a pilot study of an integration of particle swarm algorithm, social knowledge adaptation and multi-agent approaches for modeling the collective search behavior of self-organized groups in an adaptive environment. The objective of this research is to apply the particle swarm metaphor as a model of social group adaptation for the dynamic environment and to provide insight and understanding of social group knowledge discovering and strategic searching. A new adaptive environment model, which dynamically reacts to the group collective searching behaviors, is proposed in this research. The simulations in the research indicate that effective communication between groups is not the necessary requirement for whole self-organized groups to achieve the efficient collective searching behavior in the adaptive environment.

  18. Particle Swarm Based Collective Searching Model for Adaptive Environment

    SciTech Connect

    Cui, Xiaohui; Patton, Robert M; Potok, Thomas E; Treadwell, Jim N

    2007-01-01

    This report presents a pilot study of an integration of particle swarm algorithm, social knowledge adaptation and multi-agent approaches for modeling the collective search behavior of self-organized groups in an adaptive environment. The objective of this research is to apply the particle swarm metaphor as a model of social group adaptation for the dynamic environment and to provide insight and understanding of social group knowledge discovering and strategic searching. A new adaptive environment model, which dynamically reacts to the group collective searching behaviors, is proposed in this research. The simulations in the research indicate that effective communication between groups is not the necessary requirement for whole self-organized groups to achieve the efficient collective searching behavior in the adaptive environment.

  19. U(6)-Phonon model of nuclear collective motion

    NASA Astrophysics Data System (ADS)

    Ganev, H. G.

    2015-05-01

    The U(6)-phonon model of nuclear collective motion with the semi-direct product structure [HW(21)]U(6) is obtained as a hydrodynamic (macroscopic) limit of the fully microscopic proton-neutron symplectic model (PNSM) with Sp(12, R) dynamical group. The phonon structure of the [HW(21)]U(6) model enables it to simultaneously include the giant monopole and quadrupole, as well as dipole resonances and their coupling to the low-lying collective states. The U(6) intrinsic structure of the [HW(21)]U(6) model, from the other side, gives a framework for the simultaneous shell-model interpretation of the ground state band and the other excited low-lying collective bands. It follows then that the states of the whole nuclear Hilbert space which can be put into one-to-one correspondence with those of a 21-dimensional oscillator with an intrinsic (base) U(6) structure. The latter can be determined in such a way that it is compatible with the proton-neutron structure of the nucleus. The macroscopic limit of the Sp(12, R) algebra, therefore, provides a rigorous mechanism for implementing the unified model ideas of coupling the valence particles to the core collective degrees of freedom within a fully microscopic framework without introducing redundant variables or violating the Pauli principle.

  20. A simple generative model of collective online behavior.

    PubMed

    Gleeson, James P; Cellai, Davide; Onnela, Jukka-Pekka; Porter, Mason A; Reed-Tsochas, Felix

    2014-07-22

    Human activities increasingly take place in online environments, providing novel opportunities for relating individual behaviors to population-level outcomes. In this paper, we introduce a simple generative model for the collective behavior of millions of social networking site users who are deciding between different software applications. Our model incorporates two distinct mechanisms: one is associated with recent decisions of users, and the other reflects the cumulative popularity of each application. Importantly, although various combinations of the two mechanisms yield long-time behavior that is consistent with data, the only models that reproduce the observed temporal dynamics are those that strongly emphasize the recent popularity of applications over their cumulative popularity. This demonstrates--even when using purely observational data without experimental design--that temporal data-driven modeling can effectively distinguish between competing microscopic mechanisms, allowing us to uncover previously unidentified aspects of collective online behavior.

  1. A simple generative model of collective online behavior.

    PubMed

    Gleeson, James P; Cellai, Davide; Onnela, Jukka-Pekka; Porter, Mason A; Reed-Tsochas, Felix

    2014-07-22

    Human activities increasingly take place in online environments, providing novel opportunities for relating individual behaviors to population-level outcomes. In this paper, we introduce a simple generative model for the collective behavior of millions of social networking site users who are deciding between different software applications. Our model incorporates two distinct mechanisms: one is associated with recent decisions of users, and the other reflects the cumulative popularity of each application. Importantly, although various combinations of the two mechanisms yield long-time behavior that is consistent with data, the only models that reproduce the observed temporal dynamics are those that strongly emphasize the recent popularity of applications over their cumulative popularity. This demonstrates--even when using purely observational data without experimental design--that temporal data-driven modeling can effectively distinguish between competing microscopic mechanisms, allowing us to uncover previously unidentified aspects of collective online behavior. PMID:25002470

  2. Building and Sustaining Digital Collections: Models for Libraries and Museums.

    ERIC Educational Resources Information Center

    Council on Library and Information Resources, Washington, DC.

    In February 2001, the Council on Library and Information Resources (CLIR) and the National Initiative for a Networked Cultural Heritage (NINCH) convened a meeting to discuss how museums and libraries are building digital collections and what business models are available to sustain them. A group of museum and library senior executives met with…

  3. The proton-neutron symplectic model of nuclear collective motions

    NASA Astrophysics Data System (ADS)

    Ganev, H. G.

    2016-06-01

    The proton-neutron symplectic model of nuclear collective motion is presented. It is shown that it appears as a natural multi-major-shell extension of the generalized proton- neutron SU(3) scheme which includes rotations with intrinsic vortex as well as monopole, quadrupole and dipole giant resonance vibrational degrees of freedom.

  4. Emergent collective decision-making: Control, model and behavior

    NASA Astrophysics Data System (ADS)

    Shen, Tian

    In this dissertation we study emergent collective decision-making in social groups with time-varying interactions and heterogeneously informed individuals. First we analyze a nonlinear dynamical systems model motivated by animal collective motion with heterogeneously informed subpopulations, to examine the role of uninformed individuals. We find through formal analysis that adding uninformed individuals in a group increases the likelihood of a collective decision. Secondly, we propose a model for human shared decision-making with continuous-time feedback and where individuals have little information about the true preferences of other group members. We study model equilibria using bifurcation analysis to understand how the model predicts decisions based on the critical threshold parameters that represent an individual's tradeoff between social and environmental influences. Thirdly, we analyze continuous-time data of pairs of human subjects performing an experimental shared tracking task using our second proposed model in order to understand transient behavior and the decision-making process. We fit the model to data and show that it reproduces a wide range of human behaviors surprisingly well, suggesting that the model may have captured the mechanisms of observed behaviors. Finally, we study human behavior from a game-theoretic perspective by modeling the aforementioned tracking task as a repeated game with incomplete information. We show that the majority of the players are able to converge to playing Nash equilibrium strategies. We then suggest with simulations that the mean field evolution of strategies in the population resemble replicator dynamics, indicating that the individual strategies may be myopic. Decisions form the basis of control and problems involving deciding collectively between alternatives are ubiquitous in nature and in engineering. Understanding how multi-agent systems make decisions among alternatives also provides insight for designing

  5. Forecasting rain events - Meteorological models or collective intelligence?

    NASA Astrophysics Data System (ADS)

    Arazy, Ofer; Halfon, Noam; Malkinson, Dan

    2015-04-01

    Collective intelligence is shared (or group) intelligence that emerges from the collective efforts of many individuals. Collective intelligence is the aggregate of individual contributions: from simple collective decision making to more sophisticated aggregations such as in crowdsourcing and peer-production systems. In particular, collective intelligence could be used in making predictions about future events, for example by using prediction markets to forecast election results, stock prices, or the outcomes of sport events. To date, there is little research regarding the use of collective intelligence for prediction of weather forecasting. The objective of this study is to investigate the extent to which collective intelligence could be utilized to accurately predict weather events, and in particular rainfall. Our analyses employ metrics of group intelligence, as well as compare the accuracy of groups' predictions against the predictions of the standard model used by the National Meteorological Services. We report on preliminary results from a study conducted over the 2013-2014 and 2014-2015 winters. We have built a web site that allows people to make predictions on precipitation levels on certain locations. During each competition participants were allowed to enter their precipitation forecasts (i.e. 'bets') at three locations and these locations changed between competitions. A precipitation competition was defined as a 48-96 hour period (depending on the expected weather conditions), bets were open 24-48 hours prior to the competition, and during betting period participants were allowed to change their bets with no limitation. In order to explore the effect of transparency, betting mechanisms varied across study's sites: full transparency (participants able to see each other's bets); partial transparency (participants see the group's average bet); and no transparency (no information of others' bets is made available). Several interesting findings emerged from

  6. A Microscopic Quantal Model for Nuclear Collective Rotation

    SciTech Connect

    Gulshani, P.

    2007-10-26

    A microscopic, quantal model to describe nuclear collective rotation in two dimensions is derived from the many-nucleon Schrodinger equation. The Schrodinger equation is transformed to a body-fixed frame to decompose the Hamiltonian into a sum of intrinsic and rotational components plus a Coriolis-centrifugal coupling term. This Hamiltonian (H) is expressed in terms of space-fixed-frame particle coordinates and momenta by using commutator of H with a rotation angle. A unified-rotational-model type wavefunction is used to obtain an intrinsic Schrodinger equation in terms of angular momentum quantum number and two-body operators. A Hartree-Fock mean-field representation of this equation is then obtained and, by means of a unitary transformation, is reduced to a form resembling that of the conventional semi-classical cranking model when exchange terms and intrinsic spurious collective excitation are ignored.

  7. On effective temperature in network models of collective behavior.

    PubMed

    Porfiri, Maurizio; Ariel, Gil

    2016-04-01

    Collective behavior of self-propelled units is studied analytically within the Vectorial Network Model (VNM), a mean-field approximation of the well-known Vicsek model. We propose a dynamical systems framework to study the stochastic dynamics of the VNM in the presence of general additive noise. We establish that a single parameter, which is a linear function of the circular mean of the noise, controls the macroscopic phase of the system-ordered or disordered. By establishing a fluctuation-dissipation relation, we posit that this parameter can be regarded as an effective temperature of collective behavior. The exact critical temperature is obtained analytically for systems with small connectivity, equivalent to low-density ensembles of self-propelled units. Numerical simulations are conducted to demonstrate the applicability of this new notion of effective temperature to the Vicsek model. The identification of an effective temperature of collective behavior is an important step toward understanding order-disorder phase transitions, informing consistent coarse-graining techniques and explaining the physics underlying the emergence of collective phenomena. PMID:27131488

  8. Modelling of collective Thomson scattering from collisional plasmas

    NASA Astrophysics Data System (ADS)

    Tierney, T. E., IV; Montgomery, D. S.; Benage, J. F., Jr.; Wysocki, F. J.; Murillo, M. S.

    2003-06-01

    Anomalous broadening of ion-acoustic modes has been observed using collective Thomson scattering from both the electron plasma and ion-acoustic waves in ion-collisional plasmas. Ion-acoustic waves may be broadened by Landau damping, plasma inhomogeneities and instrumental effects. A model was constructed to calculate the contribution of these effects based upon spatially and spectrally resolved measurements of collective Thomson scattering. Collisional broadening effects were then calculated using a modification of the Mermin formalism. The computational model was used to interpret experimental measurements of collisional damping rates in dense, moderately coupled, plasmas. Collisional broadening is weakly dependent of ion-acoustic frequency in nearly isothermal plasmas; and therefore collective Thomson scattering can be used as a measurement technique for collisional damping rates provided all additional broadening mechanisms are taken into account. This paper further demonstrates that modelling of collective Thomson scattering from ion-collisional ion-acoustic modes must account for inhomogeneities, Landau damping, and collisions in order to evaluate plasma parameters, such as temperature and average ionization.

  9. On effective temperature in network models of collective behavior.

    PubMed

    Porfiri, Maurizio; Ariel, Gil

    2016-04-01

    Collective behavior of self-propelled units is studied analytically within the Vectorial Network Model (VNM), a mean-field approximation of the well-known Vicsek model. We propose a dynamical systems framework to study the stochastic dynamics of the VNM in the presence of general additive noise. We establish that a single parameter, which is a linear function of the circular mean of the noise, controls the macroscopic phase of the system-ordered or disordered. By establishing a fluctuation-dissipation relation, we posit that this parameter can be regarded as an effective temperature of collective behavior. The exact critical temperature is obtained analytically for systems with small connectivity, equivalent to low-density ensembles of self-propelled units. Numerical simulations are conducted to demonstrate the applicability of this new notion of effective temperature to the Vicsek model. The identification of an effective temperature of collective behavior is an important step toward understanding order-disorder phase transitions, informing consistent coarse-graining techniques and explaining the physics underlying the emergence of collective phenomena.

  10. On effective temperature in network models of collective behavior

    NASA Astrophysics Data System (ADS)

    Porfiri, Maurizio; Ariel, Gil

    2016-04-01

    Collective behavior of self-propelled units is studied analytically within the Vectorial Network Model (VNM), a mean-field approximation of the well-known Vicsek model. We propose a dynamical systems framework to study the stochastic dynamics of the VNM in the presence of general additive noise. We establish that a single parameter, which is a linear function of the circular mean of the noise, controls the macroscopic phase of the system—ordered or disordered. By establishing a fluctuation-dissipation relation, we posit that this parameter can be regarded as an effective temperature of collective behavior. The exact critical temperature is obtained analytically for systems with small connectivity, equivalent to low-density ensembles of self-propelled units. Numerical simulations are conducted to demonstrate the applicability of this new notion of effective temperature to the Vicsek model. The identification of an effective temperature of collective behavior is an important step toward understanding order-disorder phase transitions, informing consistent coarse-graining techniques and explaining the physics underlying the emergence of collective phenomena.

  11. Adaptive network models of collective decision making in swarming systems.

    PubMed

    Chen, Li; Huepe, Cristián; Gross, Thilo

    2016-08-01

    We consider a class of adaptive network models where links can only be created or deleted between nodes in different states. These models provide an approximate description of a set of systems where nodes represent agents moving in physical or abstract space, the state of each node represents the agent's heading direction, and links indicate mutual awareness. We show analytically that the adaptive network description captures a phase transition to collective motion in some swarming systems, such as the Vicsek model, and that the properties of this transition are determined by the number of states (discrete heading directions) that can be accessed by each agent.

  12. Adaptive network models of collective decision making in swarming systems

    NASA Astrophysics Data System (ADS)

    Chen, Li; Huepe, Cristián; Gross, Thilo

    2016-08-01

    We consider a class of adaptive network models where links can only be created or deleted between nodes in different states. These models provide an approximate description of a set of systems where nodes represent agents moving in physical or abstract space, the state of each node represents the agent's heading direction, and links indicate mutual awareness. We show analytically that the adaptive network description captures a phase transition to collective motion in some swarming systems, such as the Vicsek model, and that the properties of this transition are determined by the number of states (discrete heading directions) that can be accessed by each agent.

  13. Adaptive network models of collective decision making in swarming systems.

    PubMed

    Chen, Li; Huepe, Cristián; Gross, Thilo

    2016-08-01

    We consider a class of adaptive network models where links can only be created or deleted between nodes in different states. These models provide an approximate description of a set of systems where nodes represent agents moving in physical or abstract space, the state of each node represents the agent's heading direction, and links indicate mutual awareness. We show analytically that the adaptive network description captures a phase transition to collective motion in some swarming systems, such as the Vicsek model, and that the properties of this transition are determined by the number of states (discrete heading directions) that can be accessed by each agent. PMID:27627342

  14. Waste collection multi objective model with real time traceability data.

    PubMed

    Faccio, Maurizio; Persona, Alessandro; Zanin, Giorgia

    2011-12-01

    Waste collection is a highly visible municipal service that involves large expenditures and difficult operational problems, plus it is expensive to operate in terms of investment costs (i.e. vehicles fleet), operational costs (i.e. fuel, maintenances) and environmental costs (i.e. emissions, noise and traffic congestions). Modern traceability devices, like volumetric sensors, identification RFID (Radio Frequency Identification) systems, GPRS (General Packet Radio Service) and GPS (Global Positioning System) technology, permit to obtain data in real time, which is fundamental to implement an efficient and innovative waste collection routing model. The basic idea is that knowing the real time data of each vehicle and the real time replenishment level at each bin makes it possible to decide, in function of the waste generation pattern, what bin should be emptied and what should not, optimizing different aspects like the total covered distance, the necessary number of vehicles and the environmental impact. This paper describes a framework about the traceability technology available in the optimization of solid waste collection, and introduces an innovative vehicle routing model integrated with the real time traceability data, starting the application in an Italian city of about 100,000 inhabitants. The model is tested and validated using simulation and an economical feasibility study is reported at the end of the paper.

  15. Modeling closure of circular wounds through coordinated collective motion

    NASA Astrophysics Data System (ADS)

    Li, David S.; Zimmermann, Juliane; Levine, Herbert

    2016-02-01

    Wound healing enables tissues to restore their original states, and is achieved through collective cell migration into the wound space, contraction of the wound edge via an actomyosin filament ‘purse-string,’ as well as cell division. Recently, experimental techniques have been developed to create wounds with various regular morphologies in epithelial monolayers, and these experiments of circular closed-contour wounds support coordinated lamellipodial cell crawling as the predominant driver of gap closure. Through utilizing a particle-based mechanical tissue simulation, exhibiting long-range coordination of cell motility, we computationally model these closed-contour experiments with a high level of agreement between experimentally observed and simulated wound closure dynamics and tissue velocity profiles. We also determine the sensitivity of wound closure time in the model to changes in cell motility force and division rate. Our simulation results confirm that circular wounds can close due to collective cell migration without the necessity for a purse-string mechanism or for cell division, and show that the alignment mechanism of cellular motility force with velocity, leading to collective motion in the model, may speed up wound closure.

  16. AdS{sub 4}/CFT{sub 3} construction from collective fields

    SciTech Connect

    Mello Koch, Robert de; Rodrigues, Joao P.; Jevicki, Antal; Jin, Kewang

    2011-01-15

    We pursue the construction of higher-spin theory in AdS{sub 4} from CFT{sub 3} of the O(N) vector model in terms of canonical collective fields. In null-plane quantization an exact map is established between the two spaces. The coordinates of the AdS{sub 4} space-time are generated from the collective coordinates of the bi-local field. This, in the light-cone gauge, provides an exact one-to-one reconstruction of bulk AdS{sub 4} space-time and higher-spin fields.

  17. Modeling species-abundance relationships in multi-species collections

    USGS Publications Warehouse

    Peng, S.; Yin, Z.; Ren, H.; Guo, Q.

    2003-01-01

    Species-abundance relationship is one of the most fundamental aspects of community ecology. Since Motomura first developed the geometric series model to describe the feature of community structure, ecologists have developed many other models to fit the species-abundance data in communities. These models can be classified into empirical and theoretical ones, including (1) statistical models, i.e., negative binomial distribution (and its extension), log-series distribution (and its extension), geometric distribution, lognormal distribution, Poisson-lognormal distribution, (2) niche models, i.e., geometric series, broken stick, overlapping niche, particulate niche, random assortment, dominance pre-emption, dominance decay, random fraction, weighted random fraction, composite niche, Zipf or Zipf-Mandelbrot model, and (3) dynamic models describing community dynamics and restrictive function of environment on community. These models have different characteristics and fit species-abundance data in various communities or collections. Among them, log-series distribution, lognormal distribution, geometric series, and broken stick model have been most widely used.

  18. Collective behavior in animal groups: theoretical models and empirical studies

    PubMed Central

    Giardina, Irene

    2008-01-01

    Collective phenomena in animal groups have attracted much attention in the last years, becoming one of the hottest topics in ethology. There are various reasons for this. On the one hand, animal grouping provides a paradigmatic example of self-organization, where collective behavior emerges in absence of centralized control. The mechanism of group formation, where local rules for the individuals lead to a coherent global state, is very general and transcends the detailed nature of its components. In this respect, collective animal behavior is a subject of great interdisciplinary interest. On the other hand, there are several important issues related to the biological function of grouping and its evolutionary success. Research in this field boasts a number of theoretical models, but much less empirical results to compare with. For this reason, even if the general mechanisms through which self-organization is achieved are qualitatively well understood, a quantitative test of the models assumptions is still lacking. New analysis on large groups, which require sophisticated technological procedures, can provide the necessary empirical data. PMID:19404431

  19. Minimal model for collective kinetochore–microtubule dynamics

    PubMed Central

    Banigan, Edward J.; Chiou, Kevin K.; Ballister, Edward R.; Mayo, Alyssa M.; Lampson, Michael A.; Liu, Andrea J.

    2015-01-01

    Chromosome segregation during cell division depends on interactions of kinetochores with dynamic microtubules (MTs). In many eukaryotes, each kinetochore binds multiple MTs, but the collective behavior of these coupled MTs is not well understood. We present a minimal model for collective kinetochore–MT dynamics, based on in vitro measurements of individual MTs and their dependence on force and kinetochore phosphorylation by Aurora B kinase. For a system of multiple MTs connected to the same kinetochore, the force–velocity relation has a bistable regime with two possible steady-state velocities: rapid shortening or slow growth. Bistability, combined with the difference between the growing and shrinking speeds, leads to center-of-mass and breathing oscillations in bioriented sister kinetochore pairs. Kinetochore phosphorylation shifts the bistable region to higher tensions, so that only the rapidly shortening state is stable at low tension. Thus, phosphorylation leads to error correction for kinetochores that are not under tension. We challenged the model with new experiments, using chemically induced dimerization to enhance Aurora B activity at metaphase kinetochores. The model suggests that the experimentally observed disordering of the metaphase plate occurs because phosphorylation increases kinetochore speeds by biasing MTs to shrink. Our minimal model qualitatively captures certain characteristic features of kinetochore dynamics, illustrates how biochemical signals such as phosphorylation may regulate the dynamics, and provides a theoretical framework for understanding other factors that control the dynamics in vivo. PMID:26417109

  20. A model for collective dynamics in ant raids.

    PubMed

    Ryan, Shawn D

    2016-05-01

    Ant raiding, the process of identifying and returning food to the nest or bivouac, is a fascinating example of collective motion in nature. During such raids ants lay pheromones to form trails for others to find a food source. In this work a coupled PDE/ODE model is introduced to study ant dynamics and pheromone concentration. The key idea is the introduction of two forms of ant dynamics: foraging and returning, each governed by different environmental and social cues. The model accounts for all aspects of the raiding cycle including local collisional interactions, the laying of pheromone along a trail, and the transition from one class of ants to another. Through analysis of an order parameter measuring the orientational order in the system, the model shows self-organization into a collective state consisting of lanes of ants moving in opposite directions as well as the transition back to the individual state once the food source is depleted matching prior experimental results. This indicates that in the absence of direct communication ants naturally form an efficient method for transporting food to the nest/bivouac. The model exhibits a continuous kinetic phase transition in the order parameter as a function of certain system parameters. The associated critical exponents are found, shedding light on the behavior of the system near the transition. PMID:26304617

  1. Collecting, Visualising, Communicating and Modelling Geographic Data for the Sciences

    NASA Astrophysics Data System (ADS)

    Crooks, A.; Hudson-Smith, A.; Milton, R.; Smith, D.; Batty, M.; Neuhaus, F.

    2009-12-01

    New web technologies and task specific software packages and services are fundamentally changing the way we share, collect, visualise, communicate and distribute geographic information. Coupled with these new technologies is the emergence of rich fine scale and extensive geographical datasets of the built environment. Such technologies and data are providing opportunities for both the social and physical sciences that were unimaginable ten years ago. Within this paper we discus such change from our own experiences at the Centre of Advanced Spatial Analysis. Specifically, how it is now possible to harness the crowd to collect peoples’ opinions about topical events such as the current financial crisis, in real time and map the results, through the use of our GMapCreator software and the MapTube website. Furthermore, such tools allow for widespread dissemination and visualisation of geographic data to whoever has an internet connection. We will explore how one can use new datasets to visualise the city using our Virtual London model as an example. Within the model individual buildings are tagged with multiple attributes providing a lens to explore the urban structure offering a plethora of research applications. We then turn to how one can visualise and communicate such data through low cost software and virtual worlds such as Crysis and Second Life with a look into their potential for modelling and finally how we disseminated much of this information through weblogs (blogs) such as Digital Urban, GIS and Agent-based modelling and Urban Tick.

  2. A New Model for Building Digital Science Education Collections

    NASA Astrophysics Data System (ADS)

    Niepold, F.; McCaffrey, M.; Morrill, C.; Ganse, J.; Weston, T.

    2005-12-01

    The Polar Regions play an integral role in how our Earth system operates. However, the Polar Regions are marginally studied in the K-12 classroom in the United States. The International Polar Year's (IPY) coordinated campaign of polar observations, research, and analysis that will be multidisciplinary in scope and international in participation offers a powerful opportunity for K-12 classroom. The IPY's scientific objective to better understand the key roles of the Polar Regions in global processes will allow students a window into the poles and this unique regions role in the Earth system. IPY will produce careful, useful scientific information that will advance our understanding of the Polar Regions and their connections to the rest of the globe. The IPY is an opportunity to inspire the next generation of very young Earth system scientists. The IPY's draft education & outreach position paper asks a key question that must guide future educational projects; "Why is the polar regions and polar research important to all people on earth?" In efforts to coordinate educational activities and collaborate with international projects, United States national agencies, and other educational initiatives, it is the purpose of this session to explore potential partnerships, while primarily recommending a model for educational product development and review. During such a large international science endeavor, numerous educational activities and opportunities are developed, but these educational programs can suffer from too many unconnected options being available to teachers and students. Additionally, activities often are incompatible with each other making classroom implementation unnecessarily complex and prohibitively time consuming for teachers. A newly develop educational activity collection technique developed for DLESE offers an effective model for IPY product gap analysis and development. The Climate Change Collection developed as a pilot project for the Digital Library

  3. Modeling local chemistry in the presence of collective phenomena.

    SciTech Connect

    Chandross, Michael Evan; Modine, Normand Arthur

    2005-01-01

    Confinement within the nanoscale pores of a zeolite strongly modifies the behavior of small molecules. Typical of many such interesting and important problems, realistic modeling of this phenomena requires simultaneously capturing the detailed behavior of chemical bonds and the possibility of collective dynamics occurring in a complex unit cell (672 atoms in the case of Zeolite-4A). Classical simulations alone cannot reliably model the breaking and formation of chemical bonds, while quantum methods alone are incapable of treating the extended length and time scales characteristic of complex dynamics. We have developed a robust and efficient model in which a small region treated with the Kohn-Sham density functional theory is embedded within a larger system represented with classical potentials. This model has been applied in concert with first-principles electronic structure calculations and classical molecular dynamics and Monte Carlo simulations to study the behavior of water, ammonia, the hydroxide ion, and the ammonium ion in Zeolite-4a. Understanding this behavior is important to the predictive modeling of the aging of Zeolite-based desiccants. In particular, we have studied the absorption of these molecules, interactions between water and the ammonium ion, and reactions between the hydroxide ion and the zeolite cage. We have shown that interactions with the extended Zeolite cage strongly modifies these local chemical phenomena, and thereby we have proven out hypothesis that capturing both local chemistry and collective phenomena is essential to realistic modeling of this system. Based on our results, we have been able to identify two possible mechanisms for the aging of Zeolite-based desiccants.

  4. Measuring and modeling behavioral decision dynamics in collective evacuation.

    PubMed

    Carlson, Jean M; Alderson, David L; Stromberg, Sean P; Bassett, Danielle S; Craparo, Emily M; Guiterrez-Villarreal, Francisco; Otani, Thomas

    2014-01-01

    Identifying and quantifying factors influencing human decision making remains an outstanding challenge, impacting the performance and predictability of social and technological systems. In many cases, system failures are traced to human factors including congestion, overload, miscommunication, and delays. Here we report results of a behavioral network science experiment, targeting decision making in a natural disaster. In a controlled laboratory setting, our results quantify several key factors influencing individual evacuation decision making in a controlled laboratory setting. The experiment includes tensions between broadcast and peer-to-peer information, and contrasts the effects of temporal urgency associated with the imminence of the disaster and the effects of limited shelter capacity for evacuees. Based on empirical measurements of the cumulative rate of evacuations as a function of the instantaneous disaster likelihood, we develop a quantitative model for decision making that captures remarkably well the main features of observed collective behavior across many different scenarios. Moreover, this model captures the sensitivity of individual- and population-level decision behaviors to external pressures, and systematic deviations from the model provide meaningful estimates of variability in the collective response. Identification of robust methods for quantifying human decisions in the face of risk has implications for policy in disasters and other threat scenarios, specifically the development and testing of robust strategies for training and control of evacuations that account for human behavior and network topologies.

  5. Collective Diffusion Model for Ion Conduction through Microscopic Channels

    PubMed Central

    Liu, Yingting; Zhu, Fangqiang

    2013-01-01

    Ion conduction through microscopic channels is of central importance in both biology and nanotechnology. To better understand the current-voltage (I-V) dependence of ion channels, here we describe and prove a collective diffusion model that quantitatively relates the spontaneous ion permeation at equilibrium to the stationary ionic fluxes driven by small voltages. The model makes it possible to determine the channel conductance in the linear I-V range from equilibrium simulations without the application of a voltage. To validate the theory, we perform molecular-dynamics simulations on two channels—a conical-shaped nanopore and the transmembrane pore of an α-hemolysin—under both equilibrium and nonequilibrium conditions. The simulations reveal substantial couplings between the motions of cations and anions, which are effectively captured by the collective coordinate in the model. Although the two channels exhibit very different linear ranges in the I-V curves, in both cases the channel conductance at small voltages is in reasonable agreement with the prediction from the equilibrium simulation. The simulations also suggest that channel charges, rather than geometric asymmetry, play a more prominent role in current rectification. PMID:23442858

  6. Measuring and Modeling Behavioral Decision Dynamics in Collective Evacuation

    PubMed Central

    Carlson, Jean M.; Alderson, David L.; Stromberg, Sean P.; Bassett, Danielle S.; Craparo, Emily M.; Guiterrez-Villarreal, Francisco; Otani, Thomas

    2014-01-01

    Identifying and quantifying factors influencing human decision making remains an outstanding challenge, impacting the performance and predictability of social and technological systems. In many cases, system failures are traced to human factors including congestion, overload, miscommunication, and delays. Here we report results of a behavioral network science experiment, targeting decision making in a natural disaster. In a controlled laboratory setting, our results quantify several key factors influencing individual evacuation decision making in a controlled laboratory setting. The experiment includes tensions between broadcast and peer-to-peer information, and contrasts the effects of temporal urgency associated with the imminence of the disaster and the effects of limited shelter capacity for evacuees. Based on empirical measurements of the cumulative rate of evacuations as a function of the instantaneous disaster likelihood, we develop a quantitative model for decision making that captures remarkably well the main features of observed collective behavior across many different scenarios. Moreover, this model captures the sensitivity of individual- and population-level decision behaviors to external pressures, and systematic deviations from the model provide meaningful estimates of variability in the collective response. Identification of robust methods for quantifying human decisions in the face of risk has implications for policy in disasters and other threat scenarios, specifically the development and testing of robust strategies for training and control of evacuations that account for human behavior and network topologies. PMID:24520331

  7. User-friendly software for modeling collective spin wave excitations

    NASA Astrophysics Data System (ADS)

    Hahn, Steven; Peterson, Peter; Fishman, Randy; Ehlers, Georg

    There exists a great need for user-friendly, integrated software that assists in the scientific analysis of collective spin wave excitations measured with inelastic neutron scattering. SpinWaveGenie is a C + + software library that simplifies the modeling of collective spin wave excitations, allowing scientists to analyze neutron scattering data with sophisticated models fast and efficiently. Furthermore, one can calculate the four-dimensional scattering function S(Q,E) to directly compare and fit calculations to experimental measurements. Its generality has been both enhanced and verified through successful modeling of a wide array of magnetic materials. Recently, we have spent considerable effort transforming SpinWaveGenie from an early prototype to a high quality free open source software package for the scientific community. S.E.H. acknowledges support by the Laboratory's Director's fund, ORNL. Work was sponsored by the Division of Scientific User Facilities, Office of Basic Energy Sciences, US Department of Energy, under Contract No. DE-AC05-00OR22725 with UT-Battelle, LLC.

  8. Modelling Influence and Opinion Evolution in Online Collective Behaviour

    PubMed Central

    Gend, Pascal; Rentfrow, Peter J.; Hendrickx, Julien M.; Blondel, Vincent D.

    2016-01-01

    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. PMID:27336834

  9. Collective dynamics of duffing oscillators: Model for dipole ripple

    SciTech Connect

    Sen, T.; Ellison, J.A.; Kauffmann, S.K.

    1995-09-01

    The emittance growth due to power supply ripple in dipoles is modeled by the collective behavior of forced Duffing oscillators. The method of averaging reduces the problem to an autonomous system. A coarse grained long time limit of the phase space density and the rate of approach to this limit are discussed in terms of the autonomous system. The equilibrium density, the rate of approach to equilibrium and the equilibrium values depend crucially on the detuning parameter. We find the frequencies which lead to the largest emittance growth in three different forcing regimes and also characterize the dependence of emittance growth on forcing amplitude in these regimes.

  10. Collective field theory of a singular supersymmetric matrix model

    SciTech Connect

    de Mello Koch, R.; Rodrigues, J.P.

    1995-05-15

    The supersymmetric collective field theory with the potential {ital v}{prime}({ital x})={omega}{ital x}{minus}{eta}/{ital x} is studied. Consistency with supersymmetry enforces a two band solution. A supersymmetric classical configuration is found, and interpreted in terms of the density of zeroes of certain Laguerre polynomials. The spectrum of the model is then studied and is seen to correspond to a massless scalar and a Majorana fermion. The {ital x} space eigenfunctions are constructed and expressed in terms of Chebyshev polynomials. Higher order interactions are also discussed.

  11. Simple model for multiple-choice collective decision making.

    PubMed

    Lee, Ching Hua; Lucas, Andrew

    2014-11-01

    We describe a simple model of heterogeneous, interacting agents making decisions between n≥2 discrete choices. For a special class of interactions, our model is the mean field description of random field Potts-like models and is effectively solved by finding the extrema of the average energy E per agent. In these cases, by studying the propagation of decision changes via avalanches, we argue that macroscopic dynamics is well captured by a gradient flow along E. We focus on the permutation symmetric case, where all n choices are (on average) the same, and spontaneous symmetry breaking (SSB) arises purely from cooperative social interactions. As examples, we show that bimodal heterogeneity naturally provides a mechanism for the spontaneous formation of hierarchies between decisions and that SSB is a preferred instability to discontinuous phase transitions between two symmetric points. Beyond the mean field limit, exponentially many stable equilibria emerge when we place this model on a graph of finite mean degree. We conclude with speculation on decision making with persistent collective oscillations. Throughout the paper, we emphasize analogies between methods of solution to our model and common intuition from diverse areas of physics, including statistical physics and electromagnetism. PMID:25493831

  12. Simple model for multiple-choice collective decision making.

    PubMed

    Lee, Ching Hua; Lucas, Andrew

    2014-11-01

    We describe a simple model of heterogeneous, interacting agents making decisions between n≥2 discrete choices. For a special class of interactions, our model is the mean field description of random field Potts-like models and is effectively solved by finding the extrema of the average energy E per agent. In these cases, by studying the propagation of decision changes via avalanches, we argue that macroscopic dynamics is well captured by a gradient flow along E. We focus on the permutation symmetric case, where all n choices are (on average) the same, and spontaneous symmetry breaking (SSB) arises purely from cooperative social interactions. As examples, we show that bimodal heterogeneity naturally provides a mechanism for the spontaneous formation of hierarchies between decisions and that SSB is a preferred instability to discontinuous phase transitions between two symmetric points. Beyond the mean field limit, exponentially many stable equilibria emerge when we place this model on a graph of finite mean degree. We conclude with speculation on decision making with persistent collective oscillations. Throughout the paper, we emphasize analogies between methods of solution to our model and common intuition from diverse areas of physics, including statistical physics and electromagnetism.

  13. Kinetic energy for the nuclear Yang-Mills collective model

    NASA Astrophysics Data System (ADS)

    Rosensteel, George; Sparks, Nick

    2015-10-01

    The Bohr-Mottelson-Frankfurt model of nuclear rotations and quadrupole vibrations is a foundational model in nuclear structure physics. The model, also called the geometrical collective model or simply GCM, has two hidden mathematical structures, one Lie group theoretic and the other differential geometric. Although the group structure has been understood for some time, the geometric structure is a new unexplored feature that shares the same mathematical origin as Yang-Mills, viz., a vector bundle with a non-abelian structure group and a connection. Using the de Rham Laplacian ▵ = * d * d from differential geometry for the kinetic energy extends significantly the physical scope of the GCM model. This Laplacian contains a ``magnetic'' term due to the coupling between base manifold rotational and fiber vorticity degrees of freedom. When the connection specializes to irrotational flow, the Laplacian reduces to the Bohr-Mottelson kinetic energy operator. More generally, the connection yields a moment of inertia that is intermediate between the extremes of irrotational flow and rigid body motion.

  14. Yang-Mills generalization of the geometrical collective model

    NASA Astrophysics Data System (ADS)

    Rosensteel, George; Sparks, Nick

    2015-04-01

    The geometrical or Bohr-Mottelson model is generalized and recast as a Yang-Mills theory. The gauge symmetry determines conservation of Kelvin circulation. The circulation commutes with the Hamiltonian when it is the sum of the kinetic energy and a potential that depends only on deformation. The conventional Bohr-Mottelson model is the special case of circulation zero, and wave functions are complex-valued. In the generalization, any quantized value of the circulation is allowed, and the wave functions are vector-valued. The Yang-Mills formulation introduces a new coupling between the geometrical and intrinsic degrees of freedom. The coupling appears in the covariant derivative term of the collective kinetic energy. This kind of coupling is sometimes called ``magnetic'' because of the analogy with electrodynamics.

  15. Collective signaling behavior in a networked-oscillator model

    NASA Astrophysics Data System (ADS)

    Liu, Z.-H.; Hui, P. M.

    2007-09-01

    We propose and study the collective behavior of a model of networked signaling objects that incorporates several ingredients of real-life systems. These ingredients include spatial inhomogeneity with grouping of signaling objects, signal attenuation with distance, and delayed and impulsive coupling between non-identical signaling objects. Depending on the coupling strength and/or time-delay effect, the model exhibits completely, partially, and locally collective signaling behavior. In particular, a correlated signaling (CS) behavior is observed in which there exist time durations when nearly a constant fraction of oscillators in the system are in the signaling state. These time durations are much longer than the duration of a spike when a single oscillator signals, and they are separated by regular intervals in which nearly all oscillators are silent. Such CS behavior is similar to that observed in biological systems such as fireflies, cicadas, crickets, and frogs. The robustness of the CS behavior against noise is also studied. It is found that properly adjusting the coupling strength and noise level could enhance the correlated behavior.

  16. Collective opinion formation model under Bayesian updating and confirmation bias

    NASA Astrophysics Data System (ADS)

    Nishi, Ryosuke; Masuda, Naoki

    2013-06-01

    We propose a collective opinion formation model with a so-called confirmation bias. The confirmation bias is a psychological effect with which, in the context of opinion formation, an individual in favor of an opinion is prone to misperceive new incoming information as supporting the current belief of the individual. Our model modifies a Bayesian decision-making model for single individuals [M. Rabin and J. L. Schrag, Q. J. Econ.0033-553310.1162/003355399555945 114, 37 (1999)] for the case of a well-mixed population of interacting individuals in the absence of the external input. We numerically simulate the model to show that all the agents eventually agree on one of the two opinions only when the confirmation bias is weak. Otherwise, the stochastic population dynamics ends up creating a disagreement configuration (also called polarization), particularly for large system sizes. A strong confirmation bias allows various final disagreement configurations with different fractions of the individuals in favor of the opposite opinions.

  17. 3-dimensional current collection model. [Of Tethered Satellite System 1

    SciTech Connect

    Hwang, Kai-Shen; Shiah, A.; Wu, S.T.; Stone, N. Alabama, University, Huntsvilll NASA, Marshall Space Flight Center, Huntsville, Ae )

    1992-07-01

    A three-dimensional, time dependent current collection model of a satellite has been developed for the TSS-1 system. The system has been simulated particularly for the Research of Plasma Electrodynamics (ROPE) experiment. The Maxwellian distributed particles with the geomagnetic field effects are applied in this numerical simulation. The preliminary results indicate that a ring current is observed surrounding the satellite in the equatorial plane. This ring current is found between the plasma sheath and the satellite surface and is oscillating with a time scale of approximately 1 microsec. This is equivalent to the electron plasma frequency. An hour glass shape of electron distribution was observed when the viewing direction is perpendicular to the equatorial plane. This result is consistent with previous findings from Linson (1969) and Antoniades et al. (1990). Electrons that are absorbed by the satellite are limited from the background ionosphere as indicated by Parker and Murphy (1967). 6 refs.

  18. Collectivity in the light xenon isotopes: A shell model study

    SciTech Connect

    Caurier, E.; Nowacki, F.; Sieja, K.; Poves, A.

    2010-12-15

    The lightest xenon isotopes are studied in the shell model framework, within a valence space that comprises all the orbits lying between the magic closures N=Z=50 and N=Z=82. The calculations produce collective deformed structures of triaxial nature that encompass nicely the known experimental data. Predictions are made for the (still unknown) N=Z nucleus {sup 108}Xe. The results are interpreted in terms of the competition between the quadrupole correlations enhanced by the pseudo-SU(3) structure of the positive parity orbits and the pairing correlations brought in by the 0h{sub 11/2} orbit. We also have studied the effect of the excitations from the {sup 100}Sn core on our predictions. We show that the backbending in this region is due to the alignment of two particles in the 0h{sub 11/2} orbit. In the N=Z case, one neutron and one proton align to J=11 and T=0. In {sup 110,112}Xe the alignment begins in the J=10, T=1 channel and it is dominantly of neutron-neutron type. Approaching the band termination the alignment of a neutron-proton pair to J=11 and T=0 takes over. In a more academic mood, we have studied the role of the isovector and isoscalar pairing correlations on the structure on the yrast bands of {sup 108,110}Xe and examined the possible existence of isovector and isoscalar pairing condensates in these N{approx}{approx}Z nuclei.

  19. Universal correlations of collective observables: Empirical phenomenology and model interpretations

    SciTech Connect

    Casten, R.F.; Zamfir, N.V. ||; Brenner, D.S.

    1994-11-01

    Universal and simple correlations of collective observables, with each other and with structural parameters such as N{sub p}N{sub n}, are discussed along with their implications for the evolution of nuclear structure.

  20. Collective (Team) Learning Process Models: A Conceptual Review

    ERIC Educational Resources Information Center

    Knapp, Randall

    2010-01-01

    Teams have become a key resource for learning and accomplishing work in organizations. The development of collective learning in specific contexts is not well understood, yet has become critical to organizational success. The purpose of this conceptual review is to inform human resource development (HRD) practice about specific team behaviors and…

  1. California Cultures: Implementing a Model for Virtual Collections

    ERIC Educational Resources Information Center

    Guerard, Genie; Chandler, Robin L.

    2006-01-01

    This article highlights the California Cultures Project as a case study examining the architecture and framework required to support the deployment of digital objects as virtual collections at the California Digital Library. Chronologically arranged, it describes the Online Archive of California (OAC) Working Group's functional requirements for…

  2. Data Collection and Cost Modeling for Library Circulation Systems.

    ERIC Educational Resources Information Center

    Bourne, Charles P.

    The objectives of the study leading to this report were to review, analyze and summarize published library cost data; and to develop a cost model and a methodology for reporting data in a more consistent and useful way. The cost model and reporting procedure were developed and tested on the circulation system of three libraries: a large university…

  3. Modeling and analysis of collective management of water resources

    NASA Astrophysics Data System (ADS)

    Tilmant, A.; van der Zaag, P.; Fortemps, P.

    2006-09-01

    Integrated Water Resources Management (IWRM) recommends, among other things, that the management of water resources systems be carried out at the lowest appropriate level in order to increase the transparency, acceptability and efficiency of the decision-making process. Empowering water users and stakeholders transforms the decision-making process by enlarging the number of point of views that must be considered as well as the set of rules through which decisions are taken. This paper investigates the impact of different group decision-making approaches on the operating policies of a water resource. To achieve this, the water resource allocation problem is formulated as an optimization problem which seeks to maximize the aggregated satisfaction of various water users corresponding to different approaches to collective choice, namely the utilitarian and the egalitarian ones. The optimal operating policies are then used in simulation and compared. The concepts are illustrated with a multipurpose reservoir in Chile. The analysis of simulation results reveals that if this reservoir were to be managed by its water users, both approaches to collective choice would yield significantly different operating policies. The paper concludes that the transfer of management to water users must be carefully implemented if a reasonable trade-off between equity and efficiency is to be achieved.

  4. Modeling and analysis of collective management of water resources

    NASA Astrophysics Data System (ADS)

    Tilmant, A.; van der Zaag, P.; Fortemps, P.

    2007-01-01

    Integrated Water Resources Management (IWRM) recommends, among other things, that the management of water resources systems be carried out at the lowest appropriate level in order to increase the transparency, acceptability and efficiency of the decision-making process. Empowering water users and stakeholders transforms the decision-making process by enlarging the number of point of views that must be considered as well as the set of rules through which decisions are taken. This paper investigates the impact of different group decision-making approaches on the operating policies of a water resource. To achieve this, the water resource allocation problem is formulated as an optimization problem which seeks to maximize the aggregated satisfaction of various water users corresponding to different approaches to collective choice, namely the utilitarian and the egalitarian ones. The optimal operating policies are then used in simulation and compared. The concepts are illustrated with a multipurpose reservoir in Chile. The analysis of simulation results reveals that if this reservoir were to be managed by its water users, both approaches to collective choice would yield significantly different operating policies. The paper concludes that the transfer of management to water users must be carefully implemented if a reasonable trade-off between equity and efficiency is to be achieved.

  5. Endogenous Crisis Waves: Stochastic Model with Synchronized Collective Behavior

    NASA Astrophysics Data System (ADS)

    Gualdi, Stanislao; Bouchaud, Jean-Philippe; Cencetti, Giulia; Tarzia, Marco; Zamponi, Francesco

    2015-02-01

    We propose a simple framework to understand commonly observed crisis waves in macroeconomic agent-based models, which is also relevant to a variety of other physical or biological situations where synchronization occurs. We compute exactly the phase diagram of the model and the location of the synchronization transition in parameter space. Many modifications and extensions can be studied, confirming that the synchronization transition is extremely robust against various sources of noise or imperfections.

  6. Guidance for Data Collection and Computational Modelling of Regulatory Networks

    PubMed Central

    Palmer, Adam Christopher; Shearwin, Keith Edward

    2010-01-01

    Many model regulatory networks are approaching the depth of characterisation of bacteriophage λ, wherein the vast majority of individual components and interactions are identified, and research can focus on understanding whole network function and the role of interactions within that broader context. In recent years, the study of the system-wide behaviour of phage λ’s genetic regulatory network has been greatly assisted by the combination of quantitative measurements with theoretical and computational analyses. Such research has demonstrated the value of a number of general principles and guidelines for making use of the interplay between experiments and modelling. In this chapter we discuss these guidelines and provide illustration through reference to case studies from phage λ biology. In our experience, computational modelling is best facilitated with a large and diverse set of quantitative, in vivo data, preferably obtained from standardised measurements and expressed as absolute units rather than relative units. Isolation of subsets of regulatory networks may render a system amenable to ‘bottom-up’ modelling, providing a valuable tool to the experimental molecular biologist. Decoupling key components and rendering their concentration or activity an independent experimental variable provide excellent information for model building, though conclusions drawn from isolated and/or decoupled systems should be checked against studies in the full physiological context; discrepancies are informative. The construction of a model makes possible in silico experiments, which are valuable tools for both the data analysis and the design of wet experiments. PMID:19381541

  7. Modeling collective & intelligent decision making of multi-cellular populations.

    PubMed

    Shin, Yong-Jun; Mahrou, Bahareh

    2014-01-01

    In the presence of unpredictable disturbances and uncertainties, cells intelligently achieve their goals by sharing information via cell-cell communication and making collective decisions, which are more reliable compared to individual decisions. Inspired by adaptive sensor network algorithms studied in communication engineering, we propose that a multi-cellular adaptive network can convert unreliable decisions by individual cells into a more reliable cell-population decision. It is demonstrated using the effector T helper (a type of immune cell) population, which plays a critical role in initiating immune reactions in response to invading foreign agents (e.g., viruses, bacteria, etc.). While each individual cell follows a simple adaptation rule, it is the combined coordination among multiple cells that leads to the manifestation of "self-organizing" decision making via cell-cell communication.

  8. Collective and static properties of model two-component plasmas

    SciTech Connect

    Arkhipov, Yu. V.; Askaruly, A.; Davletov, A. E.; Meirkanova, G. M.; Ballester, D.; Tkachenko, I. M.

    2007-08-15

    Classical MD data on the charge-charge dynamic structure factor of two-component plasmas (TCP) modeled in Phys. Rev. A 23, 2041 (1981) are analyzed using the sum rules and other exact relations. The convergent power moments of the imaginary part of the model system dielectric function are expressed in terms of its partial static structure factors, which are computed by the method of hypernetted chains using the Deutsch effective potential. High-frequency asymptotic behavior of the dielectric function is specified to include the effects of inverse bremsstrahlung. The agreement with the MD data is improved, and important statistical characteristics of the model TCP, such as the probability to find both electron and ion at one point, are determined.

  9. Collective and static properties of model two-component plasmas.

    PubMed

    Arkhipov, Yu V; Askaruly, A; Ballester, D; Davletov, A E; Meirkanova, G M; Tkachenko, I M

    2007-08-01

    Classical MD data on the charge-charge dynamic structure factor of two-component plasmas (TCP) modeled in Phys. Rev. A 23, 2041 (1981) are analyzed using the sum rules and other exact relations. The convergent power moments of the imaginary part of the model system dielectric function are expressed in terms of its partial static structure factors, which are computed by the method of hypernetted chains using the Deutsch effective potential. High-frequency asymptotic behavior of the dielectric function is specified to include the effects of inverse bremsstrahlung. The agreement with the MD data is improved, and important statistical characteristics of the model TCP, such as the probability to find both electron and ion at one point, are determined. PMID:17930158

  10. Boolean modeling of collective effects in complex networks

    PubMed Central

    Norrell, Johannes; Socolar, Joshua E. S.

    2009-01-01

    Complex systems are often modeled as Boolean networks in attempts to capture their logical structure and reveal its dynamical consequences. Approximating the dynamics of continuous variables by discrete values and Boolean logic gates may, however, introduce dynamical possibilities that are not accessible to the original system. We show that large random networks of variables coupled through continuous transfer functions often fail to exhibit the complex dynamics of corresponding Boolean models in the disordered (chaotic) regime, even when each individual function appears to be a good candidate for Boolean idealization. A suitably modified Boolean theory explains the behavior of systems in which information does not propagate faithfully down certain chains of nodes. Model networks incorporating calculated or directly measured transfer functions reported in the literature on transcriptional regulation of genes are described by the modified theory. PMID:19658525

  11. Boolean modeling of collective effects in complex networks.

    PubMed

    Norrell, Johannes; Socolar, Joshua E S

    2009-06-01

    Complex systems are often modeled as Boolean networks in attempts to capture their logical structure and reveal its dynamical consequences. Approximating the dynamics of continuous variables by discrete values and Boolean logic gates may, however, introduce dynamical possibilities that are not accessible to the original system. We show that large random networks of variables coupled through continuous transfer functions often fail to exhibit the complex dynamics of corresponding Boolean models in the disordered (chaotic) regime, even when each individual function appears to be a good candidate for Boolean idealization. A suitably modified Boolean theory explains the behavior of systems in which information does not propagate faithfully down certain chains of nodes. Model networks incorporating calculated or directly measured transfer functions reported in the literature on transcriptional regulation of genes are described by the modified theory. PMID:19658525

  12. The Diversity Challenge: A Collection of Model Programs.

    ERIC Educational Resources Information Center

    Mellander, Gustavo A., Ed.; Prochaska, Fred, Ed.

    Model programs designed to promote diversity within the West Valley-Mission Community College District (WVMCCD) in California are discussed and described in this report. First, an introductory chapter, "The Importance of Cultural Issues to Higher Education," by Gustavo A. Mellander and Fred Prochaska, reviews the diversity recommendations of the…

  13. Pricing Models and Payment Schemes for Library Collections.

    ERIC Educational Resources Information Center

    Stern, David

    2002-01-01

    Discusses new pricing and payment options for libraries in light of online products. Topics include alternative cost models rather than traditional subscriptions; use-based pricing; changes in scholarly communication due to information technology; methods to determine appropriate charges for different organizations; consortial plans; funding; and…

  14. Comparative analysis of data collection methods for individualized modeling of radiologists' visual similarity judgments

    SciTech Connect

    Tourassi, Georgia; Xu, Songhua; Yoon, Hong-Jun; Morin-Ducote, Garnetta; Hudson, Kathy

    2013-01-01

    Rationale and Objectives: We conducted an observer study to investigate how the data collection method affects the efficacy of modeling individual radiologists judgments regarding the perceptual similarity of breast masses on mammograms. Materials and Methods: Institutional review board approval was obtained prior to the study. Six observers of variable experience levels in breast imaging were recruited to assess the perceptual similarity of mammographic masses. The observers subjective judgments were collected using: (i) a rating method, (ii) a preference method, and (iii) a hybrid method combining rating and ranking. Personalized user models were developed with the collected data to predict observers opinions. The relative efficacy of each data collection method was assessed based on the classification accuracy of the resulting user models. Results: The hybrid data collection method produced significantly more accurate individualized user models of perceptual opinions with comparable and sometimes better time efficiency than the other two data collection methods. The user models derived from hybrid data were clearly superior even when developed with a dramatically smaller number of training cases. Conclusions: A hybrid method combining rating and ranking is an intuitive and efficient way for collecting subjective similarity judgments to model human perceptual opinions with a higher accuracy than other more commonly used data collection methods.

  15. Extension of the ADC Charge-Collection Model to Include Multiple Junctions

    NASA Technical Reports Server (NTRS)

    Edmonds, Larry D.

    2011-01-01

    The ADC model is a charge-collection model derived for simple p-n junction silicon diodes having a single reverse-biased p-n junction at one end and an ideal substrate contact at the other end. The present paper extends the model to include multiple junctions, and the goal is to estimate how collected charge is shared by the different junctions.

  16. Collective Philanthropy: Describing and Modeling the Ecology of Giving

    PubMed Central

    Gottesman, William L.; Reagan, Andrew James; Dodds, Peter Sheridan

    2014-01-01

    Reflective of income and wealth distributions, philanthropic gifting appears to follow an approximate power-law size distribution as measured by the size of gifts received by individual institutions. We explore the ecology of gifting by analysing data sets of individual gifts for a diverse group of institutions dedicated to education, medicine, art, public support, and religion. We find that the detailed forms of gift-size distributions differ across but are relatively constant within charity categories. We construct a model for how a donor's income affects their giving preferences in different charity categories, offering a mechanistic explanation for variations in institutional gift-size distributions. We discuss how knowledge of gift-sized distributions may be used to assess an institution's gift-giving profile, to help set fundraising goals, and to design an institution-specific giving pyramid. PMID:24983864

  17. Energy and time modelling of kerbside waste collection: Changes incurred when adding source separated food waste.

    PubMed

    Edwards, Joel; Othman, Maazuza; Burn, Stewart; Crossin, Enda

    2016-10-01

    The collection of source separated kerbside municipal FW (SSFW) is being incentivised in Australia, however such a collection is likely to increase the fuel and time a collection truck fleet requires. Therefore, waste managers need to determine whether the incentives outweigh the cost. With literature scarcely describing the magnitude of increase, and local parameters playing a crucial role in accurately modelling kerbside collection; this paper develops a new general mathematical model that predicts the energy and time requirements of a collection regime whilst incorporating the unique variables of different jurisdictions. The model, Municipal solid waste collect (MSW-Collect), is validated and shown to be more accurate at predicting fuel consumption and trucks required than other common collection models. When predicting changes incurred for five different SSFW collection scenarios, results show that SSFW scenarios require an increase in fuel ranging from 1.38% to 57.59%. There is also a need for additional trucks across most SSFW scenarios tested. All SSFW scenarios are ranked and analysed in regards to fuel consumption; sensitivity analysis is conducted to test key assumptions. PMID:27396681

  18. Energy and time modelling of kerbside waste collection: Changes incurred when adding source separated food waste.

    PubMed

    Edwards, Joel; Othman, Maazuza; Burn, Stewart; Crossin, Enda

    2016-10-01

    The collection of source separated kerbside municipal FW (SSFW) is being incentivised in Australia, however such a collection is likely to increase the fuel and time a collection truck fleet requires. Therefore, waste managers need to determine whether the incentives outweigh the cost. With literature scarcely describing the magnitude of increase, and local parameters playing a crucial role in accurately modelling kerbside collection; this paper develops a new general mathematical model that predicts the energy and time requirements of a collection regime whilst incorporating the unique variables of different jurisdictions. The model, Municipal solid waste collect (MSW-Collect), is validated and shown to be more accurate at predicting fuel consumption and trucks required than other common collection models. When predicting changes incurred for five different SSFW collection scenarios, results show that SSFW scenarios require an increase in fuel ranging from 1.38% to 57.59%. There is also a need for additional trucks across most SSFW scenarios tested. All SSFW scenarios are ranked and analysed in regards to fuel consumption; sensitivity analysis is conducted to test key assumptions.

  19. Establishing a Selection Process Model for an Ethnic Collection in a Prison Library.

    ERIC Educational Resources Information Center

    Haymann-Diaz, Barbara

    1989-01-01

    Describes a study that examined the selection process used by two inmate/library assistants to develop Hispanic and African ethnic collections in a prison library. The findings of the study are used to develop a selection process model for the development of ethnic collections using the expertise of ethnic inmate/library assistants. (25…

  20. Recent approaches to quadrupole collectivity: models, solutions and applications based on the Bohr hamiltonian

    NASA Astrophysics Data System (ADS)

    Buganu, Petricǎ; Fortunato, Lorenzo

    2016-09-01

    We review and discuss several recent approaches to quadrupole collectivity and developments of collective models and their solutions with many applications, examples and references. We focus in particular on analytic and approximate solutions of the Bohr hamiltonian of the last decade, because most of the previously published material has been already reviewed in other publications.

  1. Modeling and simulation of charge collection properties for 3D-trench electrode detector

    NASA Astrophysics Data System (ADS)

    Ding, Hao; Chen, Jianwei; Li, Zheng; Yan, Shaoan

    2015-10-01

    3D-trench electrode detectors were simulated in this paper. Charge collection of 3D-trench electrode detector was simulated using the full 3D device simulation. The induced current and collected charge caused by drifting carriers, generated by a minimum ionizing particle (MIP) incident through the detector, have been modeled and calculated. The results indicate that the total collected charge in irradiated detector change with particle incident position and radiation fluence. In addition, we have estimated the average total collected charge generated by a MIP incident in 3D-trench electrode detector.

  2. Two-channel emission model for collective quantum jumps in Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Cayayan, Lyndon; Clemens, James

    2016-05-01

    We consider a system of driven, damped Rydberg atoms with dipole-dipole energy shifts which can give rise to a Rydberg blockade when the atoms are driven on resonance and collective quantum jumps when the atoms are driven off resonance. For the damping we consider a two-channel emission model with competition between fully independent and fully collective spontaneous emission. For independent emission a quasiclassical model predicts a bistable steady state and quantum fluctuations drive collective jumps between the two bistable branches. We show that the collective emission is enhanced, relative to the independent emission, which shifts the total effective spontaneous emission rate and impacts the presence or absence of bistability predicted by the quasiclassical model.

  3. Collective coordinate approximation to the scattering of solitons in modified NLS and sine-Gordon models

    NASA Astrophysics Data System (ADS)

    Baron, H. E.; Zakrzewski, W. J.

    2016-06-01

    We investigate the validity of collective coordinate approximations to the scattering of two solitons in several classes of (1+1) dimensional field theory models. We consider models which are deformations of the sine-Gordon (SG) or the nonlinear Schrödinger (NLS) model which posses soliton solutions (which are topological (SG) or non-topological (NLS)). Our deformations preserve their topology (SG), but change their integrability properties, either completely or partially (models become `quasi-integrable').

  4. Acting in solidarity: Testing an extended dual pathway model of collective action by bystander group members.

    PubMed

    Saab, Rim; Tausch, Nicole; Spears, Russell; Cheung, Wing-Yee

    2015-09-01

    We examined predictors of collective action among bystander group members in solidarity with a disadvantaged group by extending the dual pathway model of collective action, which proposes one efficacy-based and one emotion-based path to collective action (Van Zomeren, Spears, Fischer, & Leach, 2004). Based on two proposed functions of social identity performance (Klein, Spears, & Reicher, 2007), we distinguished between the efficacy of collective action at consolidating the identity of a protest movement and its efficacy at achieving social change (political efficacy). We expected identity consolidation efficacy to positively predict collective action tendencies directly and indirectly via political efficacy. We also expected collective action tendencies to be positively predicted by moral outrage and by sympathy in response to disadvantaged outgroup's suffering. These hypotheses were supported in two surveys examining intentions to protest for Palestine in Britain (Study 1), and intentions to attend the June 4th vigil in Hong Kong to commemorate the Tiananmen massacre among a sample of Hong Kong citizens (Study 2). The contributions of these findings to research on the dual pathway model of collective action and the different functions of collective action are discussed. PMID:25406712

  5. Academic Optimism and Collective Responsibility: An Organizational Model of the Dynamics of Student Achievement

    ERIC Educational Resources Information Center

    Wu, Jason H.

    2013-01-01

    This study was designed to examine the construct of academic optimism and its relationship with collective responsibility in a sample of Taiwan elementary schools. The construct of academic optimism was tested using confirmatory factor analysis, and the whole structural model was tested with a structural equation modeling analysis. The data were…

  6. 75 FR 16840 - Proposed Extension of Information Collection Request Submitted for Public Comment; Model Employer...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-02

    ... Comment; Model Employer CHIP Notice AGENCY: Employee Benefits Security Administration, Department of Labor... ] Administration is soliciting comments on the Model CHIP Employer Notice. A copy of the information collection...(f)(3)(B)(i)(I), and section 9801(f)(3)(B)(i)(I) of the Internal Revenue Code, as added by CHIPRA,...

  7. Building on the Cornell-Yale Model: Digitizing the Radicalism Collection at Michigan State University.

    ERIC Educational Resources Information Center

    Seadle, Michael

    1998-01-01

    Summarizes the elements of the Cornell-Yale digitization model and shows how Michigan State University (MSU) has expanded the model, focusing on a project to digitize the American Radicalism Collection of the MSU Libraries. Issues of selection, quality, integrity, longevity, and access are discussed. Sidebars present MSU digitizing procedures,…

  8. Turbulent flow model for vapor collection efficiency of a high-purity silicon reactor

    NASA Technical Reports Server (NTRS)

    Srivastava, R.; Gould, R. K.

    1985-01-01

    In this study a mathematical model and a computer code based on this model was developed to allow prediction of the product distribution in chemical reactors for converting gaseous silicon compounds to condensed-phase silicon. Specifically, the model formulated describes the silicon vapor separation/collection from the developing turbulent flow stream within reactors of the Westinghouse type. Migration of the silicon vapor to the reactor walls was described by the parametric solutions presented here, in order to reduce the experimentation necessary in the design of such reactors. Calculations relating to the collection efficiencies of such reactors are presented as a function of the reactor throughflow and distance along its length.

  9. Modeling Collective Animal Behavior with a Cognitive Perspective: A Methodological Framework

    PubMed Central

    Weitz, Sebastian; Blanco, Stéphane; Fournier, Richard; Gautrais, Jacques; Jost, Christian; Theraulaz, Guy

    2012-01-01

    The last decades have seen an increasing interest in modeling collective animal behavior. Some studies try to reproduce as accurately as possible the collective dynamics and patterns observed in several animal groups with biologically plausible, individual behavioral rules. The objective is then essentially to demonstrate that the observed collective features may be the result of self-organizing processes involving quite simple individual behaviors. Other studies concentrate on the objective of establishing or enriching links between collective behavior researches and cognitive or physiological ones, which then requires that each individual rule be carefully validated. Here we discuss the methodological consequences of this additional requirement. Using the example of corpse clustering in ants, we first illustrate that it may be impossible to discriminate among alternative individual rules by considering only observational data collected at the group level. Six individual behavioral models are described: They are clearly distinct in terms of individual behaviors, they all reproduce satisfactorily the collective dynamics and distribution patterns observed in experiments, and we show theoretically that it is strictly impossible to discriminate two of these models even in the limit of an infinite amount of data whatever the accuracy level. A set of methodological steps are then listed and discussed as practical ways to partially overcome this problem. They involve complementary experimental protocols specifically designed to address the behavioral rules successively, conserving group-level data for the overall model validation. In this context, we highlight the importance of maintaining a sharp distinction between model enunciation, with explicit references to validated biological concepts, and formal translation of these concepts in terms of quantitative state variables and fittable functional dependences. Illustrative examples are provided of the benefits expected

  10. Modeling the efficiency of a magnetic needle for collecting magnetic cells

    NASA Astrophysics Data System (ADS)

    Butler, Kimberly S.; Adolphi, Natalie L.; Bryant, H. C.; Lovato, Debbie M.; Larson, Richard S.; Flynn, Edward R.

    2014-07-01

    As new magnetic nanoparticle-based technologies are developed and new target cells are identified, there is a critical need to understand the features important for magnetic isolation of specific cells in fluids, an increasingly important tool in disease research and diagnosis. To investigate magnetic cell collection, cell-sized spherical microparticles, coated with superparamagnetic nanoparticles, were suspended in (1) glycerine-water solutions, chosen to approximate the range of viscosities of bone marrow, and (2) water in which 3, 5, 10 and 100% of the total suspended microspheres are coated with magnetic nanoparticles, to model collection of rare magnetic nanoparticle-coated cells from a mixture of cells in a fluid. The magnetic microspheres were collected on a magnetic needle, and we demonstrate that the collection efficiency versus time can be modeled using a simple, heuristically-derived function, with three physically-significant parameters. The function enables experimentally-obtained collection efficiencies to be scaled to extract the effective drag of the suspending medium. The results of this analysis demonstrate that the effective drag scales linearly with fluid viscosity, as expected. Surprisingly, increasing the number of non-magnetic microspheres in the suspending fluid results increases the collection of magnetic microspheres, corresponding to a decrease in the effective drag of the medium.

  11. Modeling the efficiency of a magnetic needle for collecting magnetic cells.

    PubMed

    Butler, Kimberly S; Adolphi, Natalie L; Bryant, H C; Lovato, Debbie M; Larson, Richard S; Flynn, Edward R

    2014-07-01

    As new magnetic nanoparticle-based technologies are developed and new target cells are identified, there is a critical need to understand the features important for magnetic isolation of specific cells in fluids, an increasingly important tool in disease research and diagnosis. To investigate magnetic cell collection, cell-sized spherical microparticles, coated with superparamagnetic nanoparticles, were suspended in (1) glycerine-water solutions, chosen to approximate the range of viscosities of bone marrow, and (2) water in which 3, 5, 10 and 100% of the total suspended microspheres are coated with magnetic nanoparticles, to model collection of rare magnetic nanoparticle-coated cells from a mixture of cells in a fluid. The magnetic microspheres were collected on a magnetic needle, and we demonstrate that the collection efficiency versus time can be modeled using a simple, heuristically-derived function, with three physically-significant parameters. The function enables experimentally-obtained collection efficiencies to be scaled to extract the effective drag of the suspending medium. The results of this analysis demonstrate that the effective drag scales linearly with fluid viscosity, as expected. Surprisingly, increasing the number of non-magnetic microspheres in the suspending fluid results increases the collection of magnetic microspheres, corresponding to a decrease in the effective drag of the medium. PMID:24874577

  12. Modeling the Efficiency of a Magnetic Needle for Collecting Magnetic Cells

    PubMed Central

    Butler, Kimberly S; Adolphi, Natalie L.; Bryant, H C; Lovato, Debbie M; Larson, Richard S; Flynn, Edward R

    2014-01-01

    As new magnetic nanoparticle-based technologies are developed and new target cells are identified, there is a critical need to understand the features important for magnetic isolation of specific cells in fluids, an increasingly important tool in disease research and diagnosis. To investigate magnetic cell collection, cell-sized spherical microparticles, coated with superparamagnetic nanoparticles, were suspended in 1) glycerine-water solutions, chosen to approximate the range of viscosities of bone marrow, and 2) water in which 3, 5, 10 and 100 % of the total suspended microspheres are coated with magnetic nanoparticles, to model collection of rare magnetic nanoparticle-coated cells from a mixture of cells in a fluid. The magnetic microspheres were collected on a magnetic needle, and we demonstrate that the collection efficiency vs. time can be modeled using a simple, heuristically-derived function, with three physically-significant parameters. The function enables experimentally-obtained collection efficiencies to be scaled to extract the effective drag of the suspending medium. The results of this analysis demonstrate that the effective drag scales linearly with fluid viscosity, as expected. Surprisingly, increasing the number of non-magnetic microspheres in the suspending fluid results increases the collection of magnetic microspheres, corresponding to a decrease in the effective drag of the medium. PMID:24874577

  13. Model-driven approach to data collection and reporting for quality improvement

    PubMed Central

    Curcin, Vasa; Woodcock, Thomas; Poots, Alan J.; Majeed, Azeem; Bell, Derek

    2014-01-01

    Continuous data collection and analysis have been shown essential to achieving improvement in healthcare. However, the data required for local improvement initiatives are often not readily available from hospital Electronic Health Record (EHR) systems or not routinely collected. Furthermore, improvement teams are often restricted in time and funding thus requiring inexpensive and rapid tools to support their work. Hence, the informatics challenge in healthcare local improvement initiatives consists of providing a mechanism for rapid modelling of the local domain by non-informatics experts, including performance metric definitions, and grounded in established improvement techniques. We investigate the feasibility of a model-driven software approach to address this challenge, whereby an improvement model designed by a team is used to automatically generate required electronic data collection instruments and reporting tools. To that goal, we have designed a generic Improvement Data Model (IDM) to capture the data items and quality measures relevant to the project, and constructed Web Improvement Support in Healthcare (WISH), a prototype tool that takes user-generated IDM models and creates a data schema, data collection web interfaces, and a set of live reports, based on Statistical Process Control (SPC) for use by improvement teams. The software has been successfully used in over 50 improvement projects, with more than 700 users. We present in detail the experiences of one of those initiatives, Chronic Obstructive Pulmonary Disease project in Northwest London hospitals. The specific challenges of improvement in healthcare are analysed and the benefits and limitations of the approach are discussed. PMID:24874182

  14. Model-driven approach to data collection and reporting for quality improvement.

    PubMed

    Curcin, Vasa; Woodcock, Thomas; Poots, Alan J; Majeed, Azeem; Bell, Derek

    2014-12-01

    Continuous data collection and analysis have been shown essential to achieving improvement in healthcare. However, the data required for local improvement initiatives are often not readily available from hospital Electronic Health Record (EHR) systems or not routinely collected. Furthermore, improvement teams are often restricted in time and funding thus requiring inexpensive and rapid tools to support their work. Hence, the informatics challenge in healthcare local improvement initiatives consists of providing a mechanism for rapid modelling of the local domain by non-informatics experts, including performance metric definitions, and grounded in established improvement techniques. We investigate the feasibility of a model-driven software approach to address this challenge, whereby an improvement model designed by a team is used to automatically generate required electronic data collection instruments and reporting tools. To that goal, we have designed a generic Improvement Data Model (IDM) to capture the data items and quality measures relevant to the project, and constructed Web Improvement Support in Healthcare (WISH), a prototype tool that takes user-generated IDM models and creates a data schema, data collection web interfaces, and a set of live reports, based on Statistical Process Control (SPC) for use by improvement teams. The software has been successfully used in over 50 improvement projects, with more than 700 users. We present in detail the experiences of one of those initiatives, Chronic Obstructive Pulmonary Disease project in Northwest London hospitals. The specific challenges of improvement in healthcare are analysed and the benefits and limitations of the approach are discussed.

  15. Model-driven approach to data collection and reporting for quality improvement.

    PubMed

    Curcin, Vasa; Woodcock, Thomas; Poots, Alan J; Majeed, Azeem; Bell, Derek

    2014-12-01

    Continuous data collection and analysis have been shown essential to achieving improvement in healthcare. However, the data required for local improvement initiatives are often not readily available from hospital Electronic Health Record (EHR) systems or not routinely collected. Furthermore, improvement teams are often restricted in time and funding thus requiring inexpensive and rapid tools to support their work. Hence, the informatics challenge in healthcare local improvement initiatives consists of providing a mechanism for rapid modelling of the local domain by non-informatics experts, including performance metric definitions, and grounded in established improvement techniques. We investigate the feasibility of a model-driven software approach to address this challenge, whereby an improvement model designed by a team is used to automatically generate required electronic data collection instruments and reporting tools. To that goal, we have designed a generic Improvement Data Model (IDM) to capture the data items and quality measures relevant to the project, and constructed Web Improvement Support in Healthcare (WISH), a prototype tool that takes user-generated IDM models and creates a data schema, data collection web interfaces, and a set of live reports, based on Statistical Process Control (SPC) for use by improvement teams. The software has been successfully used in over 50 improvement projects, with more than 700 users. We present in detail the experiences of one of those initiatives, Chronic Obstructive Pulmonary Disease project in Northwest London hospitals. The specific challenges of improvement in healthcare are analysed and the benefits and limitations of the approach are discussed. PMID:24874182

  16. Collective motion of motile cilia: from human airways to model systems

    NASA Astrophysics Data System (ADS)

    Cicuta, Pietro; Feriani, Luigi; Chioccioli, Maurizio; Kotar, Jurij

    Mammalian airways are a fantastic playground of nonlinear phenomena, from the function of individual active filaments, to the emerging collective behaviour, to the rheology of the mucus solution surrounding cilia. We have been investigating the fundamental physics of this system through a variety of model system approaches, both experimental and computational. In the last year we have started measurements on living human cells, observing cilia shape during beating, and measuring speed and coherence of the collective dynamics. We report on significant differences in the collective motion in ciliated cell carpets from a variety of diseases, and we attempt to reconcile the collective dynamical phenotypes to the properties of individual filaments and the mechanics of the environment.

  17. Exploring the dynamics of collective cognition using a computational model of cognitive dissonance

    NASA Astrophysics Data System (ADS)

    Smart, Paul R.; Sycara, Katia; Richardson, Darren P.

    2013-05-01

    The socially-distributed nature of cognitive processing in a variety of organizational settings means that there is increasing scientific interest in the factors that affect collective cognition. In military coalitions, for example, there is a need to understand how factors such as communication network topology, trust, cultural differences and the potential for miscommunication affects the ability of distributed teams to generate high quality plans, to formulate effective decisions and to develop shared situation awareness. The current paper presents a computational model and associated simulation capability for performing in silico experimental analyses of collective sensemaking. This model can be used in combination with the results of human experimental studies in order to improve our understanding of the factors that influence collective sensemaking processes.

  18. Dynamical modeling of collective behavior from pigeon flight data: flock cohesion and dispersion.

    PubMed

    Dieck Kattas, Graciano; Xu, Xiao-Ke; Small, Michael

    2012-01-01

    Several models of flocking have been promoted based on simulations with qualitatively naturalistic behavior. In this paper we provide the first direct application of computational modeling methods to infer flocking behavior from experimental field data. We show that this approach is able to infer general rules for interaction, or lack of interaction, among members of a flock or, more generally, any community. Using experimental field measurements of homing pigeons in flight we demonstrate the existence of a basic distance dependent attraction/repulsion relationship and show that this rule is sufficient to explain collective behavior observed in nature. Positional data of individuals over time are used as input data to a computational algorithm capable of building complex nonlinear functions that can represent the system behavior. Topological nearest neighbor interactions are considered to characterize the components within this model. The efficacy of this method is demonstrated with simulated noisy data generated from the classical (two dimensional) Vicsek model. When applied to experimental data from homing pigeon flights we show that the more complex three dimensional models are capable of simulating trajectories, as well as exhibiting realistic collective dynamics. The simulations of the reconstructed models are used to extract properties of the collective behavior in pigeons, and how it is affected by changing the initial conditions of the system. Our results demonstrate that this approach may be applied to construct models capable of simulating trajectories and collective dynamics using experimental field measurements of herd movement. From these models, the behavior of the individual agents (animals) may be inferred. PMID:22479176

  19. Dynamical Modeling of Collective Behavior from Pigeon Flight Data: Flock Cohesion and Dispersion

    PubMed Central

    Xu, Xiao-Ke; Small, Michael

    2012-01-01

    Several models of flocking have been promoted based on simulations with qualitatively naturalistic behavior. In this paper we provide the first direct application of computational modeling methods to infer flocking behavior from experimental field data. We show that this approach is able to infer general rules for interaction, or lack of interaction, among members of a flock or, more generally, any community. Using experimental field measurements of homing pigeons in flight we demonstrate the existence of a basic distance dependent attraction/repulsion relationship and show that this rule is sufficient to explain collective behavior observed in nature. Positional data of individuals over time are used as input data to a computational algorithm capable of building complex nonlinear functions that can represent the system behavior. Topological nearest neighbor interactions are considered to characterize the components within this model. The efficacy of this method is demonstrated with simulated noisy data generated from the classical (two dimensional) Vicsek model. When applied to experimental data from homing pigeon flights we show that the more complex three dimensional models are capable of simulating trajectories, as well as exhibiting realistic collective dynamics. The simulations of the reconstructed models are used to extract properties of the collective behavior in pigeons, and how it is affected by changing the initial conditions of the system. Our results demonstrate that this approach may be applied to construct models capable of simulating trajectories and collective dynamics using experimental field measurements of herd movement. From these models, the behavior of the individual agents (animals) may be inferred. PMID:22479176

  20. Random interactions in the geometric collective model and the E(5) potential

    SciTech Connect

    Zhang, Jing-Ye; Zamfir, N. V.; Casten, R. F.; Caprio, M. A.

    2001-07-01

    In a study parallel to one recently carried out for the interacting boson model, the behavior of the geometric collective model (GCM) with (partially restricted) random interactions is studied. In particular, we study the frequency distribution of E(4{sub 1}{sup +})/E(2{sub 1}{sup +}) ratios. In addition, we characterize those GCM potentials giving E(5) spectra and distinguish them from others giving R{sub 4/2}{approx}2.3 but non-E(5) spectra.

  1. Collective Bargaining and the Community College: A Process Model for Management Teams.

    ERIC Educational Resources Information Center

    Langan, Alfred "Bud"; And Others

    The model presented in this monograph was designed to aid state and district school systems and college administrators in dealing with the challenge of faculty collective bargaining in Washington community colleges. First, Chapter 1 provides a historical analysis of the laws and statutes relating to negotiations in the state's community colleges.…

  2. Performance Standards and Evaluation in IR Test Collections: Vector-Space and Other Retrieval Models.

    ERIC Educational Resources Information Center

    Shaw, W. M., Jr.; And Others

    1997-01-01

    Describes a study that computed the low performance standards for queries in 17 test collections. Predicted by the hypergeometric distribution, the standards represent the highest level of retrieval effectiveness attributable to chance. Operational levels of performance for vector-space and other retrieval models were compared to the standards.…

  3. A model for cell density effect on stress fiber alignment and collective directional migration

    NASA Astrophysics Data System (ADS)

    Abeddoust, Mohammad; Shamloo, Amir

    2015-12-01

    In this study, numerical simulation of collective cell migration is presented in order to mimic the group migration of endothelial cells subjected to the concentration gradients of a biochemical factor. The developed 2D model incorporates basic elements of the cell, including both the cell membrane and the cell cytoskeleton, based on a viscoelastic cell mechanic model. Various cell processes—including cell random walk, cell-cell interactions, cell chemotaxis, and cellular cytoskeleton rearrangements—are considered and analyzed in our developed model. After validating the model by using available experimental data, the model is used to investigate various important parameters during collective cell chemotaxis, such as cell density, cytoskeleton organization, stress fiber reorientations, and intracellular forces. The results suggest that increasing the cell density causes the cell-cell interactions to affect the orientation of stress fibers throughout the cytoskeleton and makes the stress fibers more aligned in the direction of the imposed concentration gradient. This improved alignment of the stress fibers correlates with the intensification of the intracellular forces transferred in the gradient direction; this improves the cell group migration. Comparison of the obtained results with available experimental observations of collective chemotaxis of endothelial cells shows an interesting agreement.

  4. A model for cell density effect on stress fiber alignment and collective directional migration.

    PubMed

    Abeddoust, Mohammad; Shamloo, Amir

    2015-12-01

    In this study, numerical simulation of collective cell migration is presented in order to mimic the group migration of endothelial cells subjected to the concentration gradients of a biochemical factor. The developed 2D model incorporates basic elements of the cell, including both the cell membrane and the cell cytoskeleton, based on a viscoelastic cell mechanic model. Various cell processes--including cell random walk, cell-cell interactions, cell chemotaxis, and cellular cytoskeleton rearrangements--are considered and analyzed in our developed model. After validating the model by using available experimental data, the model is used to investigate various important parameters during collective cell chemotaxis, such as cell density, cytoskeleton organization, stress fiber reorientations, and intracellular forces. The results suggest that increasing the cell density causes the cell-cell interactions to affect the orientation of stress fibers throughout the cytoskeleton and makes the stress fibers more aligned in the direction of the imposed concentration gradient. This improved alignment of the stress fibers correlates with the intensification of the intracellular forces transferred in the gradient direction; this improves the cell group migration. Comparison of the obtained results with available experimental observations of collective chemotaxis of endothelial cells shows an interesting agreement. PMID:26717999

  5. Optimisation of MSW collection routes for minimum fuel consumption using 3D GIS modelling.

    PubMed

    Tavares, G; Zsigraiova, Z; Semiao, V; Carvalho, M G

    2009-03-01

    Collection of municipal solid waste (MSW) may account for more than 70% of the total waste management budget, most of which is for fuel costs. It is therefore crucial to optimise the routing network used for waste collection and transportation. This paper proposes the use of geographical information systems (GIS) 3D route modelling software for waste collection and transportation, which adds one more degree of freedom to the system and allows driving routes to be optimised for minimum fuel consumption. The model takes into account the effects of road inclination and vehicle weight. It is applied to two different cases: routing waste collection vehicles in the city of Praia, the capital of Cape Verde, and routing the transport of waste from different municipalities of Santiago Island to an incineration plant. For the Praia city region, the 3D model that minimised fuel consumption yielded cost savings of 8% as compared with an approach that simply calculated the shortest 3D route. Remarkably, this was true despite the fact that the GIS-recommended fuel reduction route was actually 1.8% longer than the shortest possible travel distance. For the Santiago Island case, the difference was even more significant: a 12% fuel reduction for a similar total travel distance. These figures indicate the importance of considering both the relief of the terrain and fuel consumption in selecting a suitable cost function to optimise vehicle routing. PMID:18835768

  6. Models in animal collective decision-making: information uncertainty and conflicting preferences.

    PubMed

    Conradt, Larissa

    2012-04-01

    Collective decision-making plays a central part in the lives of many social animals. Two important factors that influence collective decision-making are information uncertainty and conflicting preferences. Here, I bring together, and briefly review, basic models relating to animal collective decision-making in situations with information uncertainty and in situations with conflicting preferences between group members. The intention is to give an overview about the different types of modelling approaches that have been employed and the questions that they address and raise. Despite the use of a wide range of different modelling techniques, results show a coherent picture, as follows. Relatively simple cognitive mechanisms can lead to effective information pooling. Groups often face a trade-off between decision accuracy and speed, but appropriate fine-tuning of behavioural parameters could achieve high accuracy while maintaining reasonable speed. The right balance of interdependence and independence between animals is crucial for maintaining group cohesion and achieving high decision accuracy. In conflict situations, a high degree of decision-sharing between individuals is predicted, as well as transient leadership and leadership according to needs and physiological status. Animals often face crucial trade-offs between maintaining group cohesion and influencing the decision outcome in their own favour. Despite the great progress that has been made, there remains one big gap in our knowledge: how do animals make collective decisions in situations when information uncertainty and conflict of interest operate simultaneously?

  7. Models in animal collective decision-making: information uncertainty and conflicting preferences

    PubMed Central

    Conradt, Larissa

    2012-01-01

    Collective decision-making plays a central part in the lives of many social animals. Two important factors that influence collective decision-making are information uncertainty and conflicting preferences. Here, I bring together, and briefly review, basic models relating to animal collective decision-making in situations with information uncertainty and in situations with conflicting preferences between group members. The intention is to give an overview about the different types of modelling approaches that have been employed and the questions that they address and raise. Despite the use of a wide range of different modelling techniques, results show a coherent picture, as follows. Relatively simple cognitive mechanisms can lead to effective information pooling. Groups often face a trade-off between decision accuracy and speed, but appropriate fine-tuning of behavioural parameters could achieve high accuracy while maintaining reasonable speed. The right balance of interdependence and independence between animals is crucial for maintaining group cohesion and achieving high decision accuracy. In conflict situations, a high degree of decision-sharing between individuals is predicted, as well as transient leadership and leadership according to needs and physiological status. Animals often face crucial trade-offs between maintaining group cohesion and influencing the decision outcome in their own favour. Despite the great progress that has been made, there remains one big gap in our knowledge: how do animals make collective decisions in situations when information uncertainty and conflict of interest operate simultaneously? PMID:23565335

  8. Modeling and analysis of collective cell migration in an in vivo three-dimensional environment

    PubMed Central

    Dai, Wei; Prasad, Mohit; Luo, Junjie; Gov, Nir S.; Montell, Denise J.

    2016-01-01

    A long-standing question in collective cell migration has been what might be the relative advantage of forming a cluster over migrating individually. Does an increase in the size of a collectively migrating group of cells enable them to sample the chemical gradient over a greater distance because the difference between front and rear of a cluster would be greater than for single cells? We combined theoretical modeling with experiments to study collective migration of the border cells in-between nurse cells in the Drosophila egg chamber. We discovered that cluster size is positively correlated with migration speed, up to a particular point above which speed plummets. This may be due to the effect of viscous drag from surrounding nurse cells together with confinement of all of the cells within a stiff extracellular matrix. The model predicts no relationship between cluster size and velocity for cells moving on a flat surface, in contrast to movement within a 3D environment. Our analyses also suggest that the overall chemoattractant profile in the egg chamber is likely to be exponential, with the highest concentration in the oocyte. These findings provide insights into collective chemotaxis by combining theoretical modeling with experimentation. PMID:27035964

  9. Flocking and Turning: a New Model for Self-organized Collective Motion

    NASA Astrophysics Data System (ADS)

    Cavagna, Andrea; Del Castello, Lorenzo; Giardina, Irene; Grigera, Tomas; Jelic, Asja; Melillo, Stefania; Mora, Thierry; Parisi, Leonardo; Silvestri, Edmondo; Viale, Massimiliano; Walczak, Aleksandra M.

    2015-02-01

    Birds in a flock move in a correlated way, resulting in large polarization of velocities. A good understanding of this collective behavior exists for linear motion of the flock. Yet observing actual birds, the center of mass of the group often turns giving rise to more complicated dynamics, still keeping strong polarization of the flock. Here we propose novel dynamical equations for the collective motion of polarized animal groups that account for correlated turning including solely social forces. We exploit rotational symmetries and conservation laws of the problem to formulate a theory in terms of generalized coordinates of motion for the velocity directions akin to a Hamiltonian formulation for rotations. We explicitly derive the correspondence between this formulation and the dynamics of the individual velocities, thus obtaining a new model of collective motion. In the appropriate overdamped limit we recover the well-known Vicsek model, which dissipates rotational information and does not allow for polarized turns. Although the new model has its most vivid success in describing turning groups, its dynamics is intrinsically different from previous ones in a wide dynamical regime, while reducing to the hydrodynamic description of Toner and Tu at very large length-scales. The derived framework is therefore general and it may describe the collective motion of any strongly polarized active matter system.

  10. Onset of collective motion in locusts is captured by a minimal model.

    PubMed

    Dyson, Louise; Yates, Christian A; Buhl, Jerome; McKane, Alan J

    2015-01-01

    We present a minimal model to describe the onset of collective motion seen when a population of locusts are placed in an annular arena. At low densities motion is disordered, while at high densities locusts march in a common direction, which may reverse during the experiment. The data are well captured by an individual-based model, in which demographic noise leads to the observed density-dependent effects. By fitting the model parameters to equation-free coefficients, we give a quantitative comparison, showing time series, stationary distributions, and the mean switching times between states. PMID:26651724

  11. HOCOMOCO: expansion and enhancement of the collection of transcription factor binding sites models.

    PubMed

    Kulakovskiy, Ivan V; Vorontsov, Ilya E; Yevshin, Ivan S; Soboleva, Anastasiia V; Kasianov, Artem S; Ashoor, Haitham; Ba-Alawi, Wail; Bajic, Vladimir B; Medvedeva, Yulia A; Kolpakov, Fedor A; Makeev, Vsevolod J

    2016-01-01

    Models of transcription factor (TF) binding sites provide a basis for a wide spectrum of studies in regulatory genomics, from reconstruction of regulatory networks to functional annotation of transcripts and sequence variants. While TFs may recognize different sequence patterns in different conditions, it is pragmatic to have a single generic model for each particular TF as a baseline for practical applications. Here we present the expanded and enhanced version of HOCOMOCO (http://hocomoco.autosome.ru and http://www.cbrc.kaust.edu.sa/hocomoco10), the collection of models of DNA patterns, recognized by transcription factors. HOCOMOCO now provides position weight matrix (PWM) models for binding sites of 601 human TFs and, in addition, PWMs for 396 mouse TFs. Furthermore, we introduce the largest up to date collection of dinucleotide PWM models for 86 (52) human (mouse) TFs. The update is based on the analysis of massive ChIP-Seq and HT-SELEX datasets, with the validation of the resulting models on in vivo data. To facilitate a practical application, all HOCOMOCO models are linked to gene and protein databases (Entrez Gene, HGNC, UniProt) and accompanied by precomputed score thresholds. Finally, we provide command-line tools for PWM and diPWM threshold estimation and motif finding in nucleotide sequences. PMID:26586801

  12. HOCOMOCO: expansion and enhancement of the collection of transcription factor binding sites models.

    PubMed

    Kulakovskiy, Ivan V; Vorontsov, Ilya E; Yevshin, Ivan S; Soboleva, Anastasiia V; Kasianov, Artem S; Ashoor, Haitham; Ba-Alawi, Wail; Bajic, Vladimir B; Medvedeva, Yulia A; Kolpakov, Fedor A; Makeev, Vsevolod J

    2016-01-01

    Models of transcription factor (TF) binding sites provide a basis for a wide spectrum of studies in regulatory genomics, from reconstruction of regulatory networks to functional annotation of transcripts and sequence variants. While TFs may recognize different sequence patterns in different conditions, it is pragmatic to have a single generic model for each particular TF as a baseline for practical applications. Here we present the expanded and enhanced version of HOCOMOCO (http://hocomoco.autosome.ru and http://www.cbrc.kaust.edu.sa/hocomoco10), the collection of models of DNA patterns, recognized by transcription factors. HOCOMOCO now provides position weight matrix (PWM) models for binding sites of 601 human TFs and, in addition, PWMs for 396 mouse TFs. Furthermore, we introduce the largest up to date collection of dinucleotide PWM models for 86 (52) human (mouse) TFs. The update is based on the analysis of massive ChIP-Seq and HT-SELEX datasets, with the validation of the resulting models on in vivo data. To facilitate a practical application, all HOCOMOCO models are linked to gene and protein databases (Entrez Gene, HGNC, UniProt) and accompanied by precomputed score thresholds. Finally, we provide command-line tools for PWM and diPWM threshold estimation and motif finding in nucleotide sequences.

  13. Computational model of collective nest selection by ants with heterogeneous acceptance thresholds

    PubMed Central

    Masuda, Naoki; O'shea-Wheller, Thomas A.; Doran, Carolina; Franks, Nigel R.

    2015-01-01

    Collective decision-making is a characteristic of societies ranging from ants to humans. The ant Temnothorax albipennis is known to use quorum sensing to collectively decide on a new home; emigration to a new nest site occurs when the number of ants favouring the new site becomes quorate. There are several possible mechanisms by which ant colonies can select the best nest site among alternatives based on a quorum mechanism. In this study, we use computational models to examine the implications of heterogeneous acceptance thresholds across individual ants in collective nest choice behaviour. We take a minimalist approach to develop a differential equation model and a corresponding non-spatial agent-based model. We show, consistent with existing empirical evidence, that heterogeneity in acceptance thresholds is a viable mechanism for efficient nest choice behaviour. In particular, we show that the proposed models show speed–accuracy trade-offs and speed–cohesion trade-offs when we vary the number of scouts or the quorum threshold. PMID:26543578

  14. Computational model of collective nest selection by ants with heterogeneous acceptance thresholds.

    PubMed

    Masuda, Naoki; O'shea-Wheller, Thomas A; Doran, Carolina; Franks, Nigel R

    2015-06-01

    Collective decision-making is a characteristic of societies ranging from ants to humans. The ant Temnothorax albipennis is known to use quorum sensing to collectively decide on a new home; emigration to a new nest site occurs when the number of ants favouring the new site becomes quorate. There are several possible mechanisms by which ant colonies can select the best nest site among alternatives based on a quorum mechanism. In this study, we use computational models to examine the implications of heterogeneous acceptance thresholds across individual ants in collective nest choice behaviour. We take a minimalist approach to develop a differential equation model and a corresponding non-spatial agent-based model. We show, consistent with existing empirical evidence, that heterogeneity in acceptance thresholds is a viable mechanism for efficient nest choice behaviour. In particular, we show that the proposed models show speed-accuracy trade-offs and speed-cohesion trade-offs when we vary the number of scouts or the quorum threshold. PMID:26543578

  15. Developing a collective future: creating a culture specific nurse caring practice model for hospitals.

    PubMed

    MacDonald, M R; Miller-Grolla, L

    1995-01-01

    Nurses continue to struggle with the knowledge that practice within a conceptual context is imperative, yet operationalizing theory-based practice has been fraught with challenges and frustrations. It is timely, given the current environment, for nurses to reflect personally and collectively on the processes and meanings of nursing. Caring theories have been examined with increasing frequency recently, as nurse leaders and theorists explore the profession using alternative frames of reference. The authors discuss the concepts central to development of a practice-based nurse caring model in a community hospital and review the process of nurse-caring model development. Concepts central to the development of the model include: individual;-collective experience as theory; cargiver-client congruence in perceptions of nurse caring; institutions as culture-specific environments. The ongoing process of theory development was initiated by data collection through focus group discussions on nurse-caring experiences and definitions. Twenty-four staff RNs and RNAs were interviewed by a trained facilitator. Audiotaped data were later transcribed and subjected to content analysis for initial theme and definition development. A parallel exercise was carried out with hospital patients using the same methodology. Subsequent analysis included validation of findings by both groups. Examinations of constructs as the theory development evolves will be expedited by both staff and in consultation with Dr. Madeleine Leininger and other external nurse-caring theorists. The Health Centre intends to operationalize and implement its nurse-caring model as an outcome of this long term project. Assumptions integral to the purpose of the project have been validated by staff response. Concepts and their relationships appear to achieve acceptance and be congruent with this nursing group's values and the way in which they practice. Observations to date indicate that collective development of a

  16. Modeling keratinocyte wound healing dynamics: Cell-cell adhesion promotes sustained collective migration.

    PubMed

    Nardini, John T; Chapnick, Douglas A; Liu, Xuedong; Bortz, David M

    2016-07-01

    The in vitro migration of keratinocyte cell sheets displays behavioral and biochemical similarities to the in vivo wound healing response of keratinocytes in animal model systems. In both cases, ligand-dependent Epidermal Growth Factor Receptor (EGFR) activation is sufficient to elicit collective cell migration into the wound. Previous mathematical modeling studies of in vitro wound healing assays assume that physical connections between cells have a hindering effect on cell migration, but biological literature suggests a more complicated story. By combining mathematical modeling and experimental observations of collectively migrating sheets of keratinocytes, we investigate the role of cell-cell adhesion during in vitro keratinocyte wound healing assays. We develop and compare two nonlinear diffusion models of the wound healing process in which cell-cell adhesion either hinders or promotes migration. Both models can accurately fit the leading edge propagation of cell sheets during wound healing when using a time-dependent rate of cell-cell adhesion strength. The model that assumes a positive role of cell-cell adhesion on migration, however, is robust to changes in the leading edge definition and yields a qualitatively accurate density profile. Using RNAi for the critical adherens junction protein, α-catenin, we demonstrate that cell sheets with wild type cell-cell adhesion expression maintain migration into the wound longer than cell sheets with decreased cell-cell adhesion expression, which fails to exhibit collective migration. Our modeling and experimental data thus suggest that cell-cell adhesion promotes sustained migration as cells pull neighboring cells into the wound during wound healing.

  17. Modeling keratinocyte wound healing dynamics: Cell-cell adhesion promotes sustained collective migration.

    PubMed

    Nardini, John T; Chapnick, Douglas A; Liu, Xuedong; Bortz, David M

    2016-07-01

    The in vitro migration of keratinocyte cell sheets displays behavioral and biochemical similarities to the in vivo wound healing response of keratinocytes in animal model systems. In both cases, ligand-dependent Epidermal Growth Factor Receptor (EGFR) activation is sufficient to elicit collective cell migration into the wound. Previous mathematical modeling studies of in vitro wound healing assays assume that physical connections between cells have a hindering effect on cell migration, but biological literature suggests a more complicated story. By combining mathematical modeling and experimental observations of collectively migrating sheets of keratinocytes, we investigate the role of cell-cell adhesion during in vitro keratinocyte wound healing assays. We develop and compare two nonlinear diffusion models of the wound healing process in which cell-cell adhesion either hinders or promotes migration. Both models can accurately fit the leading edge propagation of cell sheets during wound healing when using a time-dependent rate of cell-cell adhesion strength. The model that assumes a positive role of cell-cell adhesion on migration, however, is robust to changes in the leading edge definition and yields a qualitatively accurate density profile. Using RNAi for the critical adherens junction protein, α-catenin, we demonstrate that cell sheets with wild type cell-cell adhesion expression maintain migration into the wound longer than cell sheets with decreased cell-cell adhesion expression, which fails to exhibit collective migration. Our modeling and experimental data thus suggest that cell-cell adhesion promotes sustained migration as cells pull neighboring cells into the wound during wound healing. PMID:27105673

  18. Mapping out the solid waste generation and collection models: The case of Kampala City.

    PubMed

    Kinobe, Joel R; Niwagaba, Charles B; Gebresenbet, Girma; Komakech, Allan J; Vinnerås, Björn

    2015-02-01

    This paper presents a mapping of the waste collection systems in Kampala city, using geographical information system (GIS) ArcGIS mapping software. It discusses the existing models of waste collection to the final disposal destinations. It was found that food and yard wastes constitute 92.7% of the waste generated in Kampala. Recyclables and other special wastes constitute only 7.3% of the total waste, mainly because of the increased level of reuse and recycling activities. The generation rate of solid wastes was on average, 582, 169, 105, and 90 tons/day from poor areas, upscale wealthier areas, business centers, and market areas respectively. This tonnage of waste was collected, transported, and disposed of at the city landfill. The study found that in total, residential areas of poor people generate more waste than other categories stated earlier, mainly because of their large populations. In total, there were 133 unofficial temporary storage sites acknowledged by Kampala Capital City Authority (KCCA) but not formally designated, 59 illegal dump sites, and 35 officially recognized temporary waste storage locations. This paper presents large-scale data that can help with understanding the collection models and their influence on solid waste management in Kampala city, which could be used for similar cities in developing countries. PMID:25947055

  19. Collective Flocking Dynamics: Long Rang Order in a Non-Equilibrium 2D XY Model

    NASA Astrophysics Data System (ADS)

    Tu, Yuhai

    1996-03-01

    We propose and study a non-equilibrium continuum dynamical model for the collective motion of large groups of biological organisms (e.g., flocks of birds, slime molds, schools of fishs, etc.) (J. Toner and Y. Tu, Phys. Rev. Lett.), 75(23), 4326(1995) Our model becomes highly non-trivial, and different from the equilibrium model, for dmodel exhibits a broken continuous symmetry even in d=2. Our model describes a large universality class of microscopic rules, including those recently simulated by Vicsek et. al.( T. Vicsek et. al. , Phys. Rev. Lett.) 75, 1226(95).

  20. From Mindless Masses to Small Groups: Conceptualizing Collective Behavior in Crowd Modeling

    PubMed Central

    2015-01-01

    Computer simulations are increasingly used to monitor and predict behavior at large crowd events, such as mass gatherings, festivals and evacuations. We critically examine the crowd modeling literature and call for future simulations of crowd behavior to be based more closely on findings from current social psychological research. A systematic review was conducted on the crowd modeling literature (N = 140 articles) to identify the assumptions about crowd behavior that modelers use in their simulations. Articles were coded according to the way in which crowd structure was modeled. It was found that 2 broad types are used: mass approaches and small group approaches. However, neither the mass nor the small group approaches can accurately simulate the large collective behavior that has been found in extensive empirical research on crowd events. We argue that to model crowd behavior realistically, simulations must use methods which allow crowd members to identify with each other, as suggested by self-categorization theory. PMID:26388685

  1. DEVA: An extensible ontology-based annotation model for visual document collections

    NASA Astrophysics Data System (ADS)

    Jelmini, Carlo; Marchand-Maillet, Stephane

    2003-01-01

    The description of visual documents is a fundamental aspect of any efficient information management system, but the process of manually annotating large collections of documents is tedious and far from being perfect. The need for a generic and extensible annotation model therefore arises. In this paper, we present DEVA, an open, generic and expressive multimedia annotation framework. DEVA is an extension of the Dublin Core specification. The model can represent the semantic content of any visual document. It is described in the ontology language DAML+OIL and can easily be extended with external specialized ontologies, adapting the vocabulary to the given application domain. In parallel, we present the Magritte annotation tool, which is an early prototype that validates the DEVA features. Magritte allows to manually annotating image collections. It is designed with a modular and extensible architecture, which enables the user to dynamically adapt the user interface to specialized ontologies merged into DEVA.

  2. Models of population-based analyses for data collected from large extended families

    PubMed Central

    Lee, Elisa T.; Howard, Barbara V.; Fabsitz, Richard R.; Devereux, Richard B.; MacCluer, Jean W.; Laston, Sandra; Comuzzie, Anthony G.; Shara, Nawar M.; Welty, Thomas K.

    2014-01-01

    Large studies of extended families usually collect valuable phenotypic data that may have scientific value for purposes other than testing genetic hypotheses if the families were not selected in a biased manner. These purposes include assessing population-based associations of diseases with risk factors/covariates and estimating population characteristics such as disease prevalence and incidence. Relatedness among participants however, violates the traditional assumption of independent observations in these classic analyses. The commonly used adjustment method for relatedness in population-based analyses is to use marginal models, in which clusters (families) are assumed to be independent (unrelated) with a simple and identical covariance (family) structure such as those called independent, exchangeable and unstructured covariance structures. However, using these simple covariance structures may not be optimally appropriate for outcomes collected from large extended families, and may under- or over-estimate the variances of estimators and thus lead to uncertainty in inferences. Moreover, the assumption that families are unrelated with an identical family structure in a marginal model may not be satisfied for family studies with large extended families. The aim of this paper is to propose models incorporating marginal models approaches with a covariance structure for assessing population-based associations of diseases with their risk factors/covariates and estimating population characteristics for epidemiological studies while adjusting for the complicated relatedness among outcomes (continuous/categorical, normally/non-normally distributed) collected from large extended families. We also discuss theoretical issues of the proposed models and show that the proposed models and covariance structure are appropriate for and capable of achieving the aim. PMID:20882324

  3. Utilizing a language model to improve online dynamic data collection in P300 spellers.

    PubMed

    Mainsah, Boyla O; Colwell, Kenneth A; Collins, Leslie M; Throckmorton, Chandra S

    2014-07-01

    P300 spellers provide a means of communication for individuals with severe physical limitations, especially those with locked-in syndrome, such as amyotrophic lateral sclerosis. However, P300 speller use is still limited by relatively low communication rates due to the multiple data measurements that are required to improve the signal-to-noise ratio of event-related potentials for increased accuracy. Therefore, the amount of data collection has competing effects on accuracy and spelling speed. Adaptively varying the amount of data collection prior to character selection has been shown to improve spelling accuracy and speed. The goal of this study was to optimize a previously developed dynamic stopping algorithm that uses a Bayesian approach to control data collection by incorporating a priori knowledge via a language model. Participants ( n = 17) completed online spelling tasks using the dynamic stopping algorithm, with and without a language model. The addition of the language model resulted in improved participant performance from a mean theoretical bit rate of 46.12 bits/min at 88.89% accuracy to 54.42 bits/min ( ) at 90.36% accuracy.

  4. A Relational Model of the Financial Data Collected from Local Education Agencies by a State Department of Education.

    ERIC Educational Resources Information Center

    Mills, Richard P.

    The educational community is recognizing that it has had little direct control over or knowledge of educational data collection. The objective of this paper is to present a description of presently collected financial data collected by a state education department. An entity set model is used to create a relational view of the data to facilitate…

  5. Triaxial rotor model description of quadrupole interference in collective nuclei: The P3 term

    NASA Astrophysics Data System (ADS)

    Allmond, J. M.; Wood, J. L.; Kulp, W. D.

    2009-08-01

    The triaxial rotor model with independent inertia and electric quadrupole tensors is applied to the P3 term, P3=<01||T̂(E2)||21><21||T̂(E2)||22><22||T̂(E2)||01>, which is a standard measure of quadrupole interference in collective nuclei. It is shown that the model naturally explains nuclei with anomalous signs for their P3 terms. Measurements of Q(21) in multiple-step Coulomb excitation can be significantly dependent on the sign of this term. The example of Pt194 is considered.

  6. Illustrations of the anatomical wax model collection in the "La Specola" Zoology Museum, Florence.

    PubMed

    Lotti, S; Altobelli, A; Bambi, S; Poggesi, M

    2006-01-01

    Anatomical illustration has evolved through the centuries, first having artistic and educational purposes and later more strictly medical objectives. Between the eleventh and fifteenth centuries, the analytical model (representation of individual parts, organs and systems) gave way to the composite model (description of the human body as a whole). Between the seventeenth and eighteenth centuries, there was a reversal of tendency: initially the anatomist requested the help of artists, but later the artist asked anatomists to check the accuracy of his work. In this way, anatomical illustration reached a high level of precision. This period also saw the creation of the "La Specola" Zoology Museum's collection of anatomical wax models. Initiated in the eighteenth century, it also included a series of contemporary colour illustrations executed by various artists. Most of the illustrations concern human anatomy, while a small number deal with comparative anatomy. These illustrations, each accompanied by one or more explanatory sheets, were produced to help explain the corresponding wax models. The anatomical wax model collection has been well preserved through the centuries, maintaining its ancient splendour, and it is the object of continuing research and restoration interventions.

  7. A stochastic vision-based model inspired by zebrafish collective behaviour in heterogeneous environments

    PubMed Central

    Collignon, Bertrand; Séguret, Axel; Halloy, José

    2016-01-01

    Collective motion is one of the most ubiquitous behaviours displayed by social organisms and has led to the development of numerous models. Recent advances in the understanding of sensory system and information processing by animals impels one to revise classical assumptions made in decisional algorithms. In this context, we present a model describing the three-dimensional visual sensory system of fish that adjust their trajectory according to their perception field. Furthermore, we introduce a stochastic process based on a probability distribution function to move in targeted directions rather than on a summation of influential vectors as is classically assumed by most models. In parallel, we present experimental results of zebrafish (alone or in group of 10) swimming in both homogeneous and heterogeneous environments. We use these experimental data to set the parameter values of our model and show that this perception-based approach can simulate the collective motion of species showing cohesive behaviour in heterogeneous environments. Finally, we discuss the advances of this multilayer model and its possible outcomes in biological, physical and robotic sciences. PMID:26909173

  8. Automatic Method for Building Indoor Boundary Models from Dense Point Clouds Collected by Laser Scanners

    PubMed Central

    Valero, Enrique; Adán, Antonio; Cerrada, Carlos

    2012-01-01

    In this paper we present a method that automatically yields Boundary Representation Models (B-rep) for indoors after processing dense point clouds collected by laser scanners from key locations through an existing facility. Our objective is particularly focused on providing single models which contain the shape, location and relationship of primitive structural elements of inhabited scenarios such as walls, ceilings and floors. We propose a discretization of the space in order to accurately segment the 3D data and generate complete B-rep models of indoors in which faces, edges and vertices are coherently connected. The approach has been tested in real scenarios with data coming from laser scanners yielding promising results. We have deeply evaluated the results by analyzing how reliably these elements can be detected and how accurately they are modeled. PMID:23443369

  9. Automatic method for building indoor boundary models from dense point clouds collected by laser scanners.

    PubMed

    Valero, Enrique; Adán, Antonio; Cerrada, Carlos

    2012-01-01

    In this paper we present a method that automatically yields Boundary Representation Models (B-rep) for indoors after processing dense point clouds collected by laser scanners from key locations through an existing facility. Our objective is particularly focused on providing single models which contain the shape, location and relationship of primitive structural elements of inhabited scenarios such as walls, ceilings and floors. We propose a discretization of the space in order to accurately segment the 3D data and generate complete B-rep models of indoors in which faces, edges and vertices are coherently connected. The approach has been tested in real scenarios with data coming from laser scanners yielding promising results. We have deeply evaluated the results by analyzing how reliably these elements can be detected and how accurately they are modeled.

  10. An evaluation of 1D loss model collections for the off-design performance prediction of automotive turbocharger compressors

    NASA Astrophysics Data System (ADS)

    Harley, P.; Spence, S.; Early, J.; Filsinger, D.; Dietrich, M.

    2013-12-01

    Single-zone modelling is used to assess different collections of impeller 1D loss models. Three collections of loss models have been identified in literature, and the background to each of these collections is discussed. Each collection is evaluated using three modern automotive turbocharger style centrifugal compressors; comparisons of performance for each of the collections are made. An empirical data set taken from standard hot gas stand tests for each turbocharger is used as a baseline for comparison. Compressor range is predicted in this study; impeller diffusion ratio is shown to be a useful method of predicting compressor surge in 1D, and choke is predicted using basic compressible flow theory. The compressor designer can use this as a guide to identify the most compatible collection of losses for turbocharger compressor design applications. The analysis indicates the most appropriate collection for the design of automotive turbocharger centrifugal compressors.

  11. Ground water flow modeling with sensitivity analyses to guide field data collection in a mountain watershed

    USGS Publications Warehouse

    Johnson, Raymond H.

    2007-01-01

    In mountain watersheds, the increased demand for clean water resources has led to an increased need for an understanding of ground water flow in alpine settings. In Prospect Gulch, located in southwestern Colorado, understanding the ground water flow system is an important first step in addressing metal loads from acid-mine drainage and acid-rock drainage in an area with historical mining. Ground water flow modeling with sensitivity analyses are presented as a general tool to guide future field data collection, which is applicable to any ground water study, including mountain watersheds. For a series of conceptual models, the observation and sensitivity capabilities of MODFLOW-2000 are used to determine composite scaled sensitivities, dimensionless scaled sensitivities, and 1% scaled sensitivity maps of hydraulic head. These sensitivities determine the most important input parameter(s) along with the location of observation data that are most useful for future model calibration. The results are generally independent of the conceptual model and indicate recharge in a high-elevation recharge zone as the most important parameter, followed by the hydraulic conductivities in all layers and recharge in the next lower-elevation zone. The most important observation data in determining these parameters are hydraulic heads at high elevations, with a depth of less than 100 m being adequate. Evaluation of a possible geologic structure with a different hydraulic conductivity than the surrounding bedrock indicates that ground water discharge to individual stream reaches has the potential to identify some of these structures. Results of these sensitivity analyses can be used to prioritize data collection in an effort to reduce time and money spend by collecting the most relevant model calibration data.

  12. Analysis and classification of collective behavior using generative modeling and nonlinear manifold learning.

    PubMed

    Butail, Sachit; Bollt, Erik M; Porfiri, Maurizio

    2013-11-01

    In this paper, we build a framework for the analysis and classification of collective behavior using methods from generative modeling and nonlinear manifold learning. We represent an animal group with a set of finite-sized particles and vary known features of the group structure and motion via a class of generative models to position each particle on a two-dimensional plane. Particle positions are then mapped onto training images that are processed to emphasize the features of interest and match attainable far-field videos of real animal groups. The training images serve as templates of recognizable patterns of collective behavior and are compactly represented in a low-dimensional space called embedding manifold. Two mappings from the manifold are derived: the manifold-to-image mapping serves to reconstruct new and unseen images of the group and the manifold-to-feature mapping allows frame-by-frame classification of raw video. We validate the combined framework on datasets of growing level of complexity. Specifically, we classify artificial images from the generative model, interacting self-propelled particle model, and raw overhead videos of schooling fish obtained from the literature. PMID:23933104

  13. Simulating Flying Insects Using Dynamics and Data-Driven Noise Modeling to Generate Diverse Collective Behaviors.

    PubMed

    Ren, Jiaping; Wang, Xinjie; Jin, Xiaogang; Manocha, Dinesh

    2016-01-01

    We present a biologically plausible dynamics model to simulate swarms of flying insects. Our formulation, which is based on biological conclusions and experimental observations, is designed to simulate large insect swarms of varying densities. We use a force-based model that captures different interactions between the insects and the environment and computes collision-free trajectories for each individual insect. Furthermore, we model the noise as a constructive force at the collective level and present a technique to generate noise-induced insect movements in a large swarm that are similar to those observed in real-world trajectories. We use a data-driven formulation that is based on pre-recorded insect trajectories. We also present a novel evaluation metric and a statistical validation approach that takes into account various characteristics of insect motions. In practice, the combination of Curl noise function with our dynamics model is used to generate realistic swarm simulations and emergent behaviors. We highlight its performance for simulating large flying swarms of midges, fruit fly, locusts and moths and demonstrate many collective behaviors, including aggregation, migration, phase transition, and escape responses. PMID:27187068

  14. Analysis and classification of collective behavior using generative modeling and nonlinear manifold learning.

    PubMed

    Butail, Sachit; Bollt, Erik M; Porfiri, Maurizio

    2013-11-01

    In this paper, we build a framework for the analysis and classification of collective behavior using methods from generative modeling and nonlinear manifold learning. We represent an animal group with a set of finite-sized particles and vary known features of the group structure and motion via a class of generative models to position each particle on a two-dimensional plane. Particle positions are then mapped onto training images that are processed to emphasize the features of interest and match attainable far-field videos of real animal groups. The training images serve as templates of recognizable patterns of collective behavior and are compactly represented in a low-dimensional space called embedding manifold. Two mappings from the manifold are derived: the manifold-to-image mapping serves to reconstruct new and unseen images of the group and the manifold-to-feature mapping allows frame-by-frame classification of raw video. We validate the combined framework on datasets of growing level of complexity. Specifically, we classify artificial images from the generative model, interacting self-propelled particle model, and raw overhead videos of schooling fish obtained from the literature.

  15. From behavioural analyses to models of collective motion in fish schools

    PubMed Central

    Lopez, Ugo; Gautrais, Jacques; Couzin, Iain D.; Theraulaz, Guy

    2012-01-01

    Fish schooling is a phenomenon of long-lasting interest in ethology and ecology, widely spread across taxa and ecological contexts, and has attracted much interest from statistical physics and theoretical biology as a case of self-organized behaviour. One topic of intense interest is the search of specific behavioural mechanisms at stake at the individual level and from which the school properties emerges. This is fundamental for understanding how selective pressure acting at the individual level promotes adaptive properties of schools and in trying to disambiguate functional properties from non-adaptive epiphenomena. Decades of studies on collective motion by means of individual-based modelling have allowed a qualitative understanding of the self-organization processes leading to collective properties at school level, and provided an insight into the behavioural mechanisms that result in coordinated motion. Here, we emphasize a set of paradigmatic modelling assumptions whose validity remains unclear, both from a behavioural point of view and in terms of quantitative agreement between model outcome and empirical data. We advocate for a specific and biologically oriented re-examination of these assumptions through experimental-based behavioural analysis and modelling. PMID:24312723

  16. Simulating Flying Insects Using Dynamics and Data-Driven Noise Modeling to Generate Diverse Collective Behaviors

    PubMed Central

    Ren, Jiaping; Wang, Xinjie; Manocha, Dinesh

    2016-01-01

    We present a biologically plausible dynamics model to simulate swarms of flying insects. Our formulation, which is based on biological conclusions and experimental observations, is designed to simulate large insect swarms of varying densities. We use a force-based model that captures different interactions between the insects and the environment and computes collision-free trajectories for each individual insect. Furthermore, we model the noise as a constructive force at the collective level and present a technique to generate noise-induced insect movements in a large swarm that are similar to those observed in real-world trajectories. We use a data-driven formulation that is based on pre-recorded insect trajectories. We also present a novel evaluation metric and a statistical validation approach that takes into account various characteristics of insect motions. In practice, the combination of Curl noise function with our dynamics model is used to generate realistic swarm simulations and emergent behaviors. We highlight its performance for simulating large flying swarms of midges, fruit fly, locusts and moths and demonstrate many collective behaviors, including aggregation, migration, phase transition, and escape responses. PMID:27187068

  17. Simulating Flying Insects Using Dynamics and Data-Driven Noise Modeling to Generate Diverse Collective Behaviors.

    PubMed

    Ren, Jiaping; Wang, Xinjie; Jin, Xiaogang; Manocha, Dinesh

    2016-01-01

    We present a biologically plausible dynamics model to simulate swarms of flying insects. Our formulation, which is based on biological conclusions and experimental observations, is designed to simulate large insect swarms of varying densities. We use a force-based model that captures different interactions between the insects and the environment and computes collision-free trajectories for each individual insect. Furthermore, we model the noise as a constructive force at the collective level and present a technique to generate noise-induced insect movements in a large swarm that are similar to those observed in real-world trajectories. We use a data-driven formulation that is based on pre-recorded insect trajectories. We also present a novel evaluation metric and a statistical validation approach that takes into account various characteristics of insect motions. In practice, the combination of Curl noise function with our dynamics model is used to generate realistic swarm simulations and emergent behaviors. We highlight its performance for simulating large flying swarms of midges, fruit fly, locusts and moths and demonstrate many collective behaviors, including aggregation, migration, phase transition, and escape responses.

  18. Unsteady polynya flux model solutions incorporating a parameterization for the collection thickness of consolidated new ice

    NASA Astrophysics Data System (ADS)

    Biggs, Nicholas R. T.; Willmott, Andrew J.

    This paper develops a time-dependent, two-dimensional model for the opening of a coastal polynya. The model incorporates a parameterization for the collection thickness of frazil ice at the polynya edge that is given in terms of (a) the depth of frazil ice arriving at the polynya edge, (b) the component normal to the polynya edge of the frazil ice velocity relative to the consolidated new ice velocity, and (c) a constant depth term ( hw) associated with wave radiation stress. The last term depends upon the wavelength of surface waves that are most readily generated by the wind stress, and for coastal polynyas is shown to be of the order of 5 cm. The inclusion of hw also removes possible cases of the parameterization being non-robust in the unsteady problem. Polynya opening solutions are calculated adjacent to a straight coastal barrier of finite length D, by numerically integrating Charpit's equations, a generalisation of the method of characteristics. Polynya opening times are compared with those in a constant collection depth model, when both models open to polynyas with identical steady-state area. For "long" islands ( D≫alongshore adjustment length scale La), the opening time T obeys T> Tc, where Tc is the constant collection depth opening time; when D≪ La, the inequality is reversed. Finally, month by month simulations of the opening of the St. Lawrence Island Polynya (SLIP) are presented, for which satellite-derived steady-state areas are available. In most simulations, the simulated steady-state area falls within the 90% confidence limits of the observed area.

  19. A microscopic derivation of nuclear collective rotation-vibration model and its application to nuclei

    NASA Astrophysics Data System (ADS)

    Gulshani, P.

    2016-07-01

    We derive a microscopic version of the successful phenomenological hydrodynamic model of Bohr-Davydov-Faessler-Greiner for collective rotation-vibration motion of an axially symmetric deformed nucleus. The derivation is not limited to small oscillation amplitude. The nuclear Schrodinger equation is canonically transformed to collective co-ordinates, which is then linearized using a constrained variational method. The associated constraints are imposed on the wavefunction rather than on the particle co-ordinates. The approach yields three self-consistent, time-reversal invariant, cranking-type Schrodinger equations for the rotation-vibration and intrinsic motions, and a self-consistency equation. For harmonic oscillator mean-field potentials, these equations are solved in closed forms for excitation energy, cut-off angular momentum, and other nuclear properties for the ground-state rotational band in some deformed nuclei. The results are compared with measured data.

  20. Collective behavior of asperities as a model for friction and adhesion

    NASA Astrophysics Data System (ADS)

    Hulikal, Srivatsan

    Understanding friction and adhesion in static and sliding contact of surfaces is important in numerous physical phenomena and technological applications. Most surfaces are rough at the microscale, and thus the real area of contact is only a fraction of the nominal area. The macroscopic frictional and adhesive response is determined by the collective behavior of the population of evolving and interacting microscopic contacts. This collective behavior can be very different from the behavior of individual contacts. It is thus important to understand how the macroscopic response emerges from the microscopic one. In this thesis, we develop a theoretical and computational framework to study the collective behavior. Our philosophy is to assume a simple behavior of a single asperity and study the collective response of an ensemble. Our work bridges the existing well-developed studies of single asperities with phenomenological laws that describe macroscopic rate-and-state behavior of frictional interfaces. We find that many aspects of the macroscopic behavior are robust with respect to the microscopic response. This explains why qualitatively similar frictional features are seen for a diverse range of materials. We first show that the collective response of an ensemble of one-dimensional independent viscoelastic elements interacting through a mean field reproduces many qualitative features of static and sliding friction evolution. The resulting macroscopic behavior is different from the microscopic one: for example, even if each contact is velocity-strengthening, the macroscopic behavior can be velocity-weakening. The framework is then extended to incorporate three-dimensional rough surfaces, long- range elastic interactions between contacts, and time-dependent material behaviors such as viscoelasticity and viscoplasticity. Interestingly, the mean field behavior dominates and the elastic interactions, though important from a quantitative perspective, do not change the

  1. The development of empirical models to evaluate energy use and energy cost in wastewater collection

    NASA Astrophysics Data System (ADS)

    Young, David Morgan

    This research introduces a unique data analysis method and develops empirical models to evaluate energy use and energy cost in wastewater collection systems using operational variables. From these models, several Best Management Processes (BMPs) are identified that should benefit utilities and positively impact the operation of existing infrastructure as well as the design of new infrastructure. Further, the conclusions generated herein display high transferability to certain manufacturing processes. Therefore, it is anticipated that these findings will also benefit pumping applications outside of the water sector. Wastewater treatment is often the single largest expense at the local government level. Not surprisingly, significant research effort has been expended on examining the energy used in wastewater treatment. However, the energy used in wastewater collection systems remains underexplored despite significant potential for energy savings. Estimates place potential energy savings as high as 60% within wastewater collection; which, if applied across the United States equates to the energy used by nearly 125,000 American homes. Employing three years of data from Renewable Water Resources (ReWa), the largest wastewater utility in the Upstate of South Carolina, this study aims to develop useful empirical equations that will allow utilities to efficiently evaluate the energy use and energy cost of its wastewater collection system. ReWa's participation was motivated, in part, by their recent adoption of the United States Environmental Protection Agency "Effective Utility Strategies" within which exists a focus on energy management. The study presented herein identifies two primary variables related to the energy use and cost associated with wastewater collection: Specific Energy (Es) and Specific Cost (Cs). These two variables were found to rely primarily on the volume pumped by the individual pump stations and exhibited similar power functions for the three year

  2. A Mathematical Model of Collective Cell Migration in a Three-Dimensional, Heterogeneous Environment

    PubMed Central

    Stonko, David P.; Manning, Lathiena; Starz-Gaiano, Michelle; Peercy, Bradford E.

    2015-01-01

    Cell migration is essential in animal development, homeostasis, and disease progression, but many questions remain unanswered about how this process is controlled. While many kinds of individual cell movements have been characterized, less effort has been directed towards understanding how clusters of cells migrate collectively through heterogeneous, cellular environments. To explore this, we have focused on the migration of the border cells during Drosophila egg development. In this case, a cluster of different cell types coalesce and traverse as a group between large cells, called nurse cells, in the center of the egg chamber. We have developed a new model for this collective cell migration based on the forces of adhesion, repulsion, migration and stochastic fluctuation to generate the movement of discrete cells. We implement the model using Identical Math Cells, or IMCs. IMCs can each represent one biological cell of the system, or can be aggregated using increased adhesion forces to model the dynamics of larger biological cells. The domain of interest is filled with IMCs, each assigned specific biophysical properties to mimic a diversity of cell types. Using this system, we have successfully simulated the migration of the border cell cluster through an environment filled with larger cells, which represent nurse cells. Interestingly, our simulations suggest that the forces utilized in this model are sufficient to produce behaviors of the cluster that are observed in vivo, such as rotation. Our framework was developed to capture a heterogeneous cell population, and our implementation strategy allows for diverse, but precise, initial position specification over a three- dimensional domain. Therefore, we believe that this model will be useful for not only examining aspects of Drosophila oogenesis, but also for modeling other two or three-dimensional systems that have multiple cell types and where investigating the forces between cells is of interest. PMID:25875645

  3. Modeling the Emergence of Modular Leadership Hierarchy During the Collective Motion of Herds Made of Harems

    NASA Astrophysics Data System (ADS)

    Ozogány, Katalin; Vicsek, Tamás

    2015-02-01

    Gregarious animals need to make collective decisions in order to keep their cohesiveness. Several species of them live in multilevel societies, and form herds composed of smaller communities. We present a model for the development of a leadership hierarchy in a herd consisting of loosely connected sub-groups (e.g. harems) by combining self organization and social dynamics. It starts from unfamiliar individuals without relationships and reproduces the emergence of a hierarchical and modular leadership network that promotes an effective spreading of the decisions from more capable individuals to the others, and thus gives rise to a beneficial collective decision. Our results stemming from the model are in a good agreement with our observations of a Przewalski horse herd (Hortobágy, Hungary). We find that the harem-leader to harem-member ratio observed in Przewalski horses corresponds to an optimal network in this approach regarding common success, and that the observed and modeled harem size distributions are close to a lognormal.

  4. Collective polarization model for gradient sensing via Dachsous-Fat intercellular signaling.

    PubMed

    Mani, Madhav; Goyal, Sidhartha; Irvine, Kenneth D; Shraiman, Boris I

    2013-12-17

    Dachsous-Fat signaling via the Hippo pathway influences proliferation during Drosophila development, and some of its mammalian homologs are tumor suppressors, highlighting its role as a universal growth regulator. The Fat/Hippo pathway responds to morphogen gradients and influences the in-plane polarization of cells and orientation of divisions, linking growth with tissue patterning. Remarkably, the Fat pathway transduces a growth signal through the polarization of transmembrane complexes that responds to both morphogen level and gradient. Dissection of these complex phenotypes requires a quantitative model that provides a systematic characterization of the pathway. In the absence of detailed knowledge of molecular interactions, we take a phenomenological approach that considers a broad class of simple models, which are sufficiently constrained by observations to enable insight into possible mechanisms. We predict two modes of local/cooperative interactions among Fat-Dachsous complexes, which are necessary for the collective polarization of tissues and enhanced sensitivity to weak gradients. Collective polarization convolves level and gradient of input signals, reproducing known phenotypes while generating falsifiable predictions. Our construction of a simplified signal transduction map allows a generalization of the positional value model and emphasizes the important role intercellular interactions play in growth and patterning of tissues.

  5. Crises and Collective Socio-Economic Phenomena: Simple Models and Challenges

    NASA Astrophysics Data System (ADS)

    Bouchaud, Jean-Philippe

    2013-05-01

    Financial and economic history is strewn with bubbles and crashes, booms and busts, crises and upheavals of all sorts. Understanding the origin of these events is arguably one of the most important problems in economic theory. In this paper, we review recent efforts to include heterogeneities and interactions in models of decision. We argue that the so-called Random Field Ising model ( rfim) provides a unifying framework to account for many collective socio-economic phenomena that lead to sudden ruptures and crises. We discuss different models that can capture potentially destabilizing self-referential feedback loops, induced either by herding, i.e. reference to peers, or trending, i.e. reference to the past, and that account for some of the phenomenology missing in the standard models. We discuss some empirically testable predictions of these models, for example robust signatures of rfim-like herding effects, or the logarithmic decay of spatial correlations of voting patterns. One of the most striking result, inspired by statistical physics methods, is that Adam Smith's invisible hand can fail badly at solving simple coordination problems. We also insist on the issue of time-scales, that can be extremely long in some cases, and prevent socially optimal equilibria from being reached. As a theoretical challenge, the study of so-called "detailed-balance" violating decision rules is needed to decide whether conclusions based on current models (that all assume detailed-balance) are indeed robust and generic.

  6. Gamma emission in precompound reactions: 1, Statistical model and collective gamma decay

    SciTech Connect

    Hoering, A. Washington Univ., Seattle, WA . Inst. for Nuclear Theory); Weidenmueller, H.A. )

    1992-01-01

    We extend the theory of particle-induced precompound reactions by including gamma decay. We use the Brink-Axel hypothesis and consider the gamma emission of giant dipole resonances built on the ground state and on the excited states of the composite system. The latter are modeled as multiparticle multi-hole excitations. In this way, we combine the statistical ansatz and the chaining hypothesis typical for precompound reaction theories, with the collective aspects of gamma decay. Formulas for average S-matrix and average cross section are derived in this framework.

  7. Gamma emission in precompound reactions: 1, Statistical model and collective gamma decay

    SciTech Connect

    Hoering, A. |; Weidenmueller, H.A.

    1992-09-01

    We extend the theory of particle-induced precompound reactions by including gamma decay. We use the Brink-Axel hypothesis and consider the gamma emission of giant dipole resonances built on the ground state and on the excited states of the composite system. The latter are modeled as multiparticle multi-hole excitations. In this way, we combine the statistical ansatz and the chaining hypothesis typical for precompound reaction theories, with the collective aspects of gamma decay. Formulas for average S-matrix and average cross section are derived in this framework.

  8. Collective states of odd nuclei in a model with quadrupole-octupole degrees of freedom

    SciTech Connect

    Minkov, N. Drenska, S. B.; Yotov, P.; Bonatsos, D. Scheid, W.

    2007-08-15

    We apply the collective axial quadrupole-octupole Hamiltonian to describe the rotation-vibration motion of odd nuclei with Coriolis coupling between the even-even core and the unpaired nucleon.We consider that the core oscillates coherently with respect to the quadrupole and octupole axialdeformation variables. The coupling between the core and the unpaired nucleon provides a split paritydoublet structure of the spectrum. The formalism successfully reproduces the parity-doublet splitting in a wide range of odd-A nuclei. It provides model estimations for the third angular-momentum projection K on the intrinsic symmetry axis and the related intrinsic nuclear structure.

  9. Collective response to perturbations in a data-driven fish school model

    PubMed Central

    Calovi, Daniel S.; Lopez, Ugo; Schuhmacher, Paul; Chaté, Hugues; Sire, Clément; Theraulaz, Guy

    2015-01-01

    Fish schools are able to display a rich variety of collective states and behavioural responses when they are confronted by threats. However, a school's response to perturbations may be different depending on the nature of its collective state. Here we use a previously developed data-driven fish school model to investigate how the school responds to perturbations depending on its different collective states, we measure its susceptibility to such perturbations, and exploit its relation with the intrinsic fluctuations in the school. In particular, we study how a single or a small number of perturbing individuals whose attraction and alignment parameters are different from those of the main population affect the long-term behaviour of a school. We find that the responsiveness of the school to the perturbations is maximum near the transition region between milling and schooling states where the school exhibits multistability and regularly shifts between these two states. It is also in this region that the susceptibility, and hence the fluctuations, of the polarization order parameter is maximal. We also find that a significant school's response to a perturbation only happens below a certain threshold of the noise to social interactions ratio. PMID:25631571

  10. A computer code for calculations in the algebraic collective model of the atomic nucleus

    NASA Astrophysics Data System (ADS)

    Welsh, T. A.; Rowe, D. J.

    2016-03-01

    A Maple code is presented for algebraic collective model (ACM) calculations. The ACM is an algebraic version of the Bohr model of the atomic nucleus, in which all required matrix elements are derived by exploiting the model's SU(1 , 1) × SO(5) dynamical group. This paper reviews the mathematical formulation of the ACM, and serves as a manual for the code. The code enables a wide range of model Hamiltonians to be analysed. This range includes essentially all Hamiltonians that are rational functions of the model's quadrupole moments qˆM and are at most quadratic in the corresponding conjugate momenta πˆN (- 2 ≤ M , N ≤ 2). The code makes use of expressions for matrix elements derived elsewhere and newly derived matrix elements of the operators [ π ˆ ⊗ q ˆ ⊗ π ˆ ] 0 and [ π ˆ ⊗ π ˆ ] LM. The code is made efficient by use of an analytical expression for the needed SO(5)-reduced matrix elements, and use of SO(5) ⊃ SO(3)  Clebsch-Gordan coefficients obtained from precomputed data files provided with the code.

  11. A computer code for calculations in the algebraic collective model of the atomic nucleus

    NASA Astrophysics Data System (ADS)

    Welsh, T. A.; Rowe, D. J.

    2016-03-01

    A Maple code is presented for algebraic collective model (ACM) calculations. The ACM is an algebraic version of the Bohr model of the atomic nucleus, in which all required matrix elements are derived by exploiting the model's SU(1 , 1) × SO(5) dynamical group. This paper reviews the mathematical formulation of the ACM, and serves as a manual for the code. The code enables a wide range of model Hamiltonians to be analysed. This range includes essentially all Hamiltonians that are rational functions of the model's quadrupole moments qˆM and are at most quadratic in the corresponding conjugate momenta πˆN (- 2 ≤ M , N ≤ 2). The code makes use of expressions for matrix elements derived elsewhere and newly derived matrix elements of the operators [ π ˆ ⊗ q ˆ ⊗ π ˆ ] 0 and [ π ˆ ⊗ π ˆ ] LM. The code is made efficient by use of an analytical expression for the needed SO(5)-reduced matrix elements, and use of SO(5) ⊃ SO(3) Clebsch-Gordan coefficients obtained from precomputed data files provided with the code.

  12. Triaxial rotor model description of quadrupole interference in collective nuclei: The P{sub 3} term

    SciTech Connect

    Allmond, J. M.; Wood, J. L.; Kulp, W. D.

    2009-08-15

    The triaxial rotor model with independent inertia and electric quadrupole tensors is applied to the P{sub 3} term, P{sub 3}=<0{sub 1}||T(E2)||2{sub 1}><2{sub 1}||T(E2)||2{sub 2}><2{sub 2}||T(E2)||0{sub 1}>, which is a standard measure of quadrupole interference in collective nuclei. It is shown that the model naturally explains nuclei with anomalous signs for their P{sub 3} terms. Measurements of Q(2{sub 1}) in multiple-step Coulomb excitation can be significantly dependent on the sign of this term. The example of {sup 194}Pt is considered.

  13. Shell-model configuration-interaction description of quadrupole collectivity in Te isotopes

    NASA Astrophysics Data System (ADS)

    Qi, Chong

    2016-09-01

    Systematic calculations on the spectroscopy and transition properties of even-even Te isotopes are carried out by using the large-scale shell-model configuration-interaction approach with a realistic interaction. These nuclei are of particular interest since their yrast spectra show a vibrational-like equally spaced pattern whereas the few known E 2 transitions show rotational-like behavior. This cannot be explained by available collective models. My calculations reproduce well the equally spaced spectra of those isotopes as well as the constant behavior for the B (E 2 ) values of 114Te. The calculated B (E 2 ) values of neutron-deficient and heavier Te isotopes show contrasting different behaviors along the yrast line. The B (E 2 ) of light isotopes can exhibit a nearly constant behavior up to high spins. It is shown that this is related to the enhanced neutron-proton correlation when approaching N =50 .

  14. A Mechanistic Collective Cell Model for Epithelial Colony Growth and Contact Inhibition.

    PubMed

    Aland, Sebastian; Hatzikirou, Haralambos; Lowengrub, John; Voigt, Axel

    2015-10-01

    We present a mechanistic hybrid continuum-discrete model to simulate the dynamics of epithelial cell colonies. Collective cell dynamics are modeled using continuum equations that capture plastic, viscoelastic, and elastic deformations in the clusters while providing single-cell resolution. The continuum equations can be viewed as a coarse-grained version of previously developed discrete models that treat epithelial clusters as a two-dimensional network of vertices or stochastic interacting particles and follow the framework of dynamic density functional theory appropriately modified to account for cell size and shape variability. The discrete component of the model implements cell division and thus influences cell size and shape that couple to the continuum component. The model is validated against recent in vitro studies of epithelial cell colonies using Madin-Darby canine kidney cells. In good agreement with experiments, we find that mechanical interactions and constraints on the local expansion of cell size cause inhibition of cell motion and reductive cell division. This leads to successively smaller cells and a transition from exponential to quadratic growth of the colony that is associated with a constant-thickness rim of growing cells at the cluster edge, as well as the emergence of short-range ordering and solid-like behavior. A detailed analysis of the model reveals a scale invariance of the growth and provides insight into the generation of stresses and their influence on the dynamics of the colonies. Compared to previous models, our approach has several advantages: it is independent of dimension, it can be parameterized using classical elastic properties (Poisson's ratio and Young's modulus), and it can easily be extended to incorporate multiple cell types and general substrate geometries.

  15. A Mechanistic Collective Cell Model for Epithelial Colony Growth and Contact Inhibition

    PubMed Central

    Aland, Sebastian; Hatzikirou, Haralambos; Lowengrub, John; Voigt, Axel

    2015-01-01

    We present a mechanistic hybrid continuum-discrete model to simulate the dynamics of epithelial cell colonies. Collective cell dynamics are modeled using continuum equations that capture plastic, viscoelastic, and elastic deformations in the clusters while providing single-cell resolution. The continuum equations can be viewed as a coarse-grained version of previously developed discrete models that treat epithelial clusters as a two-dimensional network of vertices or stochastic interacting particles and follow the framework of dynamic density functional theory appropriately modified to account for cell size and shape variability. The discrete component of the model implements cell division and thus influences cell size and shape that couple to the continuum component. The model is validated against recent in vitro studies of epithelial cell colonies using Madin-Darby canine kidney cells. In good agreement with experiments, we find that mechanical interactions and constraints on the local expansion of cell size cause inhibition of cell motion and reductive cell division. This leads to successively smaller cells and a transition from exponential to quadratic growth of the colony that is associated with a constant-thickness rim of growing cells at the cluster edge, as well as the emergence of short-range ordering and solid-like behavior. A detailed analysis of the model reveals a scale invariance of the growth and provides insight into the generation of stresses and their influence on the dynamics of the colonies. Compared to previous models, our approach has several advantages: it is independent of dimension, it can be parameterized using classical elastic properties (Poisson’s ratio and Young’s modulus), and it can easily be extended to incorporate multiple cell types and general substrate geometries. PMID:26445436

  16. Continuum Model of Collective Cell Migration in Wound Healing and Colony Expansion

    PubMed Central

    Arciero, Julia C.; Mi, Qi; Branca, Maria F.; Hackam, David J.; Swigon, David

    2011-01-01

    Collective cell migration plays an important role during wound healing and embryo development. Although the exact mechanisms that coordinate such migration are still unknown, experimental studies of moving cell layers have shown that the primary interactions governing the motion of the layer are the force of lamellipodia, the adhesion of cells to the substrate, and the adhesion of cells to each other. Here, we derive a two-dimensional continuum mechanical model of cell-layer migration that is based on a novel assumption of elastic deformation of the layer and incorporates basic mechanical interactions of cells as well as cell proliferation and apoptosis. The evolution equations are solved numerically using a level set method. The model successfully reproduces data from two types of experiments: 1), the contraction of an enterocyte cell layer during wound healing; and 2), the expansion of a radially symmetric colony of MDCK cells, both in the edge migration velocity and in cell-layer density. In accord with experimental observations, and in contrast to reaction-diffusion models, this model predicts a partial wound closure if lamellipod formation is inhibited at the wound edge and gives implications of the effect of spatially restricted proliferation. PMID:21281567

  17. An integrated statistical and hydraulic modelling approach for collective flood risk assessment

    NASA Astrophysics Data System (ADS)

    Lamb, Rob; Keef, Caroline; Tawn, Jonathan A.; Hankin, Barry; Dunning, Paul

    2010-05-01

    This paper presents a methodology for assessing collective flood risk based on a combination of two innovative models. The first is a multivariate statistical model for extremes of river flow or sea level, based on the conditional exceedance approach of Heffernan and Tawn (2004) and Keef et al (2009). This model is analogous to a generalised form of copula function in that it separates the joint distribution of a variable into its marginal characteristics and its dependence structure. The dependence structure is flexible in its description of the joint extremes, which has advantages for representing spatial dependence in data such as river flows. The second part of the methodology is a two-dimensional (2D) hydraulic floodplain inundation model that is applied using parallel processing technology to provide high resolution gridded flood depth data over large regions (Lamb et al., 2009). These depth grids can then be combined with a model for economic losses. We present an overview of the methodology and demonstrate through simulation studies how it can be applied to estimate the distribution function of the spatially aggregated economic losses from flooding over regions up to the scale of England and Wales, or greater. The results are also placed in the context of hydrological assessment of the probability and severity of notable historical flood events experiences in the British Isles. Heffernan J. E. and Tawn J. A. (2004) A conditional approach for multivariate extreme values (with discussion) J. R. Statist. Soc. B, 66 497-546 Keef, C., J. Tawn, and C. Svensson. (2009). Spatial risk assessment for extreme river flows. Applied Statistics 58,(5) pp 601-618 Lamb, R., Crossley, A., Waller, S. (2009) A fast 2D floodplain inundation model, Proceedings of the Institution of Civil Engineers: Water Management, 162, doi: 10.1680/wama.2009.162.1.1

  18. Distribution models for koalas in South Australia using citizen science-collected data

    PubMed Central

    Sequeira, Ana M M; Roetman, Philip E J; Daniels, Christopher B; Baker, Andrew K; Bradshaw, Corey J A

    2014-01-01

    The koala (Phascolarctos cinereus) occurs in the eucalypt forests of eastern and southern Australia and is currently threatened by habitat fragmentation, climate change, sexually transmitted diseases, and low genetic variability throughout most of its range. Using data collected during the Great Koala Count (a 1-day citizen science project in the state of South Australia), we developed generalized linear mixed-effects models to predict habitat suitability across South Australia accounting for potential errors associated with the dataset. We derived spatial environmental predictors for vegetation (based on dominant species of Eucalyptus or other vegetation), topographic water features, rain, elevation, and temperature range. We also included predictors accounting for human disturbance based on transport infrastructure (sealed and unsealed roads). We generated random pseudo-absences to account for the high prevalence bias typical of citizen-collected data. We accounted for biased sampling effort along sealed and unsealed roads by including an offset for distance to transport infrastructures. The model with the highest statistical support (wAICc ∼ 1) included all variables except rain, which was highly correlated with elevation. The same model also explained the highest deviance (61.6%), resulted in high R2(m) (76.4) and R2(c) (81.0), and had a good performance according to Cohen's κ (0.46). Cross-validation error was low (∼ 0.1). Temperature range, elevation, and rain were the best predictors of koala occurrence. Our models predict high habitat suitability in Kangaroo Island, along the Mount Lofty Ranges, and at the tips of the Eyre, Yorke and Fleurieu Peninsulas. In the highest-density region (5576 km2) of the Adelaide–Mount Lofty Ranges, a density–suitability relationship predicts a population of 113,704 (95% confidence interval: 27,685–199,723; average density = 5.0–35.8 km−2). We demonstrate the power of citizen science data for predicting species

  19. Distribution models for koalas in South Australia using citizen science-collected data.

    PubMed

    Sequeira, Ana M M; Roetman, Philip E J; Daniels, Christopher B; Baker, Andrew K; Bradshaw, Corey J A

    2014-06-01

    The koala (Phascolarctos cinereus) occurs in the eucalypt forests of eastern and southern Australia and is currently threatened by habitat fragmentation, climate change, sexually transmitted diseases, and low genetic variability throughout most of its range. Using data collected during the Great Koala Count (a 1-day citizen science project in the state of South Australia), we developed generalized linear mixed-effects models to predict habitat suitability across South Australia accounting for potential errors associated with the dataset. We derived spatial environmental predictors for vegetation (based on dominant species of Eucalyptus or other vegetation), topographic water features, rain, elevation, and temperature range. We also included predictors accounting for human disturbance based on transport infrastructure (sealed and unsealed roads). We generated random pseudo-absences to account for the high prevalence bias typical of citizen-collected data. We accounted for biased sampling effort along sealed and unsealed roads by including an offset for distance to transport infrastructures. The model with the highest statistical support (wAIC c ∼ 1) included all variables except rain, which was highly correlated with elevation. The same model also explained the highest deviance (61.6%), resulted in high R (2)(m) (76.4) and R (2)(c) (81.0), and had a good performance according to Cohen's κ (0.46). Cross-validation error was low (∼ 0.1). Temperature range, elevation, and rain were the best predictors of koala occurrence. Our models predict high habitat suitability in Kangaroo Island, along the Mount Lofty Ranges, and at the tips of the Eyre, Yorke and Fleurieu Peninsulas. In the highest-density region (5576 km(2)) of the Adelaide-Mount Lofty Ranges, a density-suitability relationship predicts a population of 113,704 (95% confidence interval: 27,685-199,723; average density = 5.0-35.8 km(-2)). We demonstrate the power of citizen science data for predicting species

  20. Study on collection efficiency of fission products by spray: Experimental device and modelling

    SciTech Connect

    Ducret, D.; Roblot, D.; Vendel, J.; Billarand, Y.

    1997-08-01

    Consequences of an hypothetical overheating reactor accident in nuclear power plants can be limited by spraying cold water drops into containment building. The spray reduces the pressure and the temperature levels by condensation of steam and leads to the washout of fission products (aerosols and gaseous iodine). The present study includes a large program devoted to the evaluation of realistic washout rates. An experimental device (named CARAIDAS) was designed and built in order to determine the collection efficiency of aerosols and iodine absorption by drops with representative conditions of post-accident atmosphere. This experimental device is presented in the paper and more particularly: (1) the experimental enclosure in which representative thermodynamic conditions can be achieved, (2) the monosized drops generator, the drops diameter measurement and the drops collector, (3) the cesium iodide aerosols generator and the aerosols measurements. Modelling of steam condensation on drops aerosols collection and iodine absorption are described. First experimental and code results on drops and aerosols behaviour are compared. 8 refs., 18 figs.

  1. Data Collection Handbook to Support Modeling Impacts of Radioactive Material in Soil and Building Structures

    SciTech Connect

    Yu, Charley; Kamboj, Sunita; Wang, Cheng; Cheng, Jing-Jy

    2015-09-01

    This handbook is an update of the 1993 version of the Data Collection Handbook and the Radionuclide Transfer Factors Report to support modeling the impact of radioactive material in soil. Many new parameters have been added to the RESRAD Family of Codes, and new measurement methodologies are available. A detailed review of available parameter databases was conducted in preparation of this new handbook. This handbook is a companion document to the user manuals when using the RESRAD (onsite) and RESRAD-OFFSITE code. It can also be used for RESRAD-BUILD code because some of the building-related parameters are included in this handbook. The RESRAD (onsite) has been developed for implementing U.S. Department of Energy Residual Radioactive Material Guidelines. Hydrogeological, meteorological, geochemical, geometrical (size, area, depth), crops and livestock, human intake, source characteristic, and building characteristic parameters are used in the RESRAD (onsite) code. The RESRAD-OFFSITE code is an extension of the RESRAD (onsite) code and can also model the transport of radionuclides to locations outside the footprint of the primary contamination. This handbook discusses parameter definitions, typical ranges, variations, and measurement methodologies. It also provides references for sources of additional information. Although this handbook was developed primarily to support the application of RESRAD Family of Codes, the discussions and values are valid for use of other pathway analysis models and codes.

  2. Geostatistical modeling of malaria endemicity using serological indicators of exposure collected through school surveys.

    PubMed

    Ashton, Ruth A; Kefyalew, Takele; Rand, Alison; Sime, Heven; Assefa, Ashenafi; Mekasha, Addis; Edosa, Wasihun; Tesfaye, Gezahegn; Cano, Jorge; Teka, Hiwot; Reithinger, Richard; Pullan, Rachel L; Drakeley, Chris J; Brooker, Simon J

    2015-07-01

    Ethiopia has a diverse ecology and geography resulting in spatial and temporal variation in malaria transmission. Evidence-based strategies are thus needed to monitor transmission intensity and target interventions. A purposive selection of dried blood spots collected during cross-sectional school-based surveys in Oromia Regional State, Ethiopia, were tested for presence of antibodies against Plasmodium falciparum and P. vivax antigens. Spatially explicit binomial models of seroprevalence were created for each species using a Bayesian framework, and used to predict seroprevalence at 5 km resolution across Oromia. School seroprevalence showed a wider prevalence range than microscopy for both P. falciparum (0-50% versus 0-12.7%) and P. vivax (0-53.7% versus 0-4.5%), respectively. The P. falciparum model incorporated environmental predictors and spatial random effects, while P. vivax seroprevalence first-order trends were not adequately explained by environmental variables, and a spatial smoothing model was developed. This is the first demonstration of serological indicators being used to detect large-scale heterogeneity in malaria transmission using samples from cross-sectional school-based surveys. The findings support the incorporation of serological indicators into periodic large-scale surveillance such as Malaria Indicator Surveys, and with particular utility for low transmission and elimination settings.

  3. Geostatistical Modeling of Malaria Endemicity using Serological Indicators of Exposure Collected through School Surveys

    PubMed Central

    Ashton, Ruth A.; Kefyalew, Takele; Rand, Alison; Sime, Heven; Assefa, Ashenafi; Mekasha, Addis; Edosa, Wasihun; Tesfaye, Gezahegn; Cano, Jorge; Teka, Hiwot; Reithinger, Richard; Pullan, Rachel L.; Drakeley, Chris J.; Brooker, Simon J.

    2015-01-01

    Ethiopia has a diverse ecology and geography resulting in spatial and temporal variation in malaria transmission. Evidence-based strategies are thus needed to monitor transmission intensity and target interventions. A purposive selection of dried blood spots collected during cross-sectional school-based surveys in Oromia Regional State, Ethiopia, were tested for presence of antibodies against Plasmodium falciparum and P. vivax antigens. Spatially explicit binomial models of seroprevalence were created for each species using a Bayesian framework, and used to predict seroprevalence at 5 km resolution across Oromia. School seroprevalence showed a wider prevalence range than microscopy for both P. falciparum (0–50% versus 0–12.7%) and P. vivax (0–53.7% versus 0–4.5%), respectively. The P. falciparum model incorporated environmental predictors and spatial random effects, while P. vivax seroprevalence first-order trends were not adequately explained by environmental variables, and a spatial smoothing model was developed. This is the first demonstration of serological indicators being used to detect large-scale heterogeneity in malaria transmission using samples from cross-sectional school-based surveys. The findings support the incorporation of serological indicators into periodic large-scale surveillance such as Malaria Indicator Surveys, and with particular utility for low transmission and elimination settings. PMID:25962770

  4. Charge collection efficiency degradation induced by MeV ions in semiconductor devices: Model and experiment

    DOE PAGESBeta

    Vittone, Ettore; Pastuovic, Zeljko; Breese, Mark B. H.; Lopez, Javier Garicia; Jaksic, Milko; Raisanen, Jyrki; Siegele, Rainer; Simon, Aliz; Vizkelethy, Gyorgy

    2016-02-08

    This study investigates both theoretically and experimentally the charge collection efficiency (CCE) degradation in silicon diodes induced by energetic ions. Ion Beam Induced Charge (IBIC) measurements carried out on n- and p-type silicon diodes which were previously irradiated with MeV He ions show evidence that the CCE degradation does not only depend on the mass, energy and fluence of the damaging ion, but also depends on the ion probe species and on the polarization state of the device. A general one-dimensional model is derived, which accounts for the ion-induced defect distribution, the ionization profile of the probing ion and themore » charge induction mechanism. Using the ionizing and non-ionizing energy loss profiles resulting from simulations based on the binary collision approximation and on the electrostatic/transport parameters of the diode under study as input, the model is able to accurately reproduce the experimental CCE degradation curves without introducing any phenomenological additional term or formula. Although limited to low level of damage, the model is quite general, including the displacement damage approach as a special case and can be applied to any semiconductor device. It provides a method to measure the capture coefficients of the radiation induced recombination centres. They can be considered indexes, which can contribute to assessing the relative radiation hardness of semiconductor materials.« less

  5. A collective coupled-channel model and mirror state energy displacements

    NASA Astrophysics Data System (ADS)

    Fraser, P. R.; Amos, K.; Canton, L.; Karataglidis, S.; van der Knijff, D.; Svenne, J. P.

    2015-09-01

    The spectra of nucleon-nucleus mirror systems allow examination of charge symmetry breaking in nucleon-nucleus interactions. To date, such examination has been performed with studies using microscopic models of structure. Herein we seek characterisation with a coupled-channel model in which the nucleon-nucleus interactions are described using a collective model prescription with the Pauli principle taken into account. The neutron-nucleus Hamiltonian is chosen to give the best match to the compound system spectrum, with emphasis on finding the correct ground state energy relative to the neutron-nucleus threshold. The Coulomb interactions for the proton-nucleus partner of a mirror pair are determined using charge distributions that match the root-mean-square charge radii of the nuclei in question. With the Coulomb interaction so defined modifying the neutron-nucleus Hamiltonian, we then predict a spectrum for the relevant proton-nucleus compound. Discrepancies in that resulting spectrum with measured values we tentatively ascribe to charge-symmetry breaking effects. We consider spectra obtained in this way for the mirror pairs 13C and 13N, 15C and 15F, and 15O and 15N, all to ˜ 10 MeV excitation.

  6. Charge collection efficiency degradation induced by MeV ions in semiconductor devices: Model and experiment

    NASA Astrophysics Data System (ADS)

    Vittone, E.; Pastuovic, Z.; Breese, M. B. H.; Garcia Lopez, J.; Jaksic, M.; Raisanen, J.; Siegele, R.; Simon, A.; Vizkelethy, G.

    2016-04-01

    This paper investigates both theoretically and experimentally the charge collection efficiency (CCE) degradation in silicon diodes induced by energetic ions. Ion Beam Induced Charge (IBIC) measurements carried out on n- and p-type silicon diodes which were previously irradiated with MeV He ions show evidence that the CCE degradation does not only depend on the mass, energy and fluence of the damaging ion, but also depends on the ion probe species and on the polarization state of the device. A general one-dimensional model is derived, which accounts for the ion-induced defect distribution, the ionization profile of the probing ion and the charge induction mechanism. Using the ionizing and non-ionizing energy loss profiles resulting from simulations based on the binary collision approximation and on the electrostatic/transport parameters of the diode under study as input, the model is able to accurately reproduce the experimental CCE degradation curves without introducing any phenomenological additional term or formula. Although limited to low level of damage, the model is quite general, including the displacement damage approach as a special case and can be applied to any semiconductor device. It provides a method to measure the capture coefficients of the radiation induced recombination centres. They can be considered indexes, which can contribute to assessing the relative radiation hardness of semiconductor materials.

  7. Loop-Closure and Gaussian Models of Collective Structural Characteristics of Capped PEO Oligomers in Water.

    PubMed

    Chaudhari, M I; Pratt, L R; Paulaitis, M E

    2015-07-23

    Parallel-tempering MD results for a CH3(CH2-O-CH2)mCH3 chain in water are exploited as a database for analysis of collective structural characteristics of the PEO globule with a goal of defining models permitting statistical thermodynamic analysis of dispersants of Corexit type. The chain structure factor, relevant to neutron scattering from a deuterated chain in null water, is considered specifically. The traditional continuum-Gaussian structure factor is inconsistent with the simple k → ∞ behavior, but we consider a discrete-Gaussian model that does achieve that consistency. Shifting and scaling the discrete-Gaussian model helps to identify the low-k to high-k transition near k ≈ 2π/0.6 nm when an empirically matched number of Gaussian links is about one-third of the total number of effective atom sites. This short distance-scale boundary of 0.6 nm is directly verified with the r space distributions, and this distance is thus identified with a natural size for coarsened monomers. The probability distribution of Rg(2) is compared with the classic predictions for both the Gaussian model and freely jointed chains. ⟨Rg(2)(j)⟩, the contribution of the jth chain segment to ⟨Rg(2)⟩, depends on the contour index about as expected for Gaussian chains despite significant quantitative discrepancies that express the swelling of these chains in water. Monomers central to the chain contour occupy the center of the chain globule. The density profiles of chain segments relative to their center of mass can show distinctive density structuring for smaller chains due to the close proximity of central elements to the globule center. However, that density structuring washes out for longer chains where many chain elements additively contribute to the density profiles. Gaussian chain models thus become more satisfactory for the density profiles for longer chains. PMID:25121580

  8. Multiscale modelling and analysis of collective decision making in swarm robotics.

    PubMed

    Vigelius, Matthias; Meyer, Bernd; Pascoe, Geoffrey

    2014-01-01

    We present a unified approach to describing certain types of collective decision making in swarm robotics that bridges from a microscopic individual-based description to aggregate properties. Our approach encompasses robot swarm experiments, microscopic and probabilistic macroscopic-discrete simulations as well as an analytic mathematical model. Following up on previous work, we identify the symmetry parameter, a measure of the progress of the swarm towards a decision, as a fundamental integrated swarm property and formulate its time evolution as a continuous-time Markov process. Contrary to previous work, which justified this approach only empirically and a posteriori, we justify it from first principles and derive hard limits on the parameter regime in which it is applicable. PMID:25369026

  9. Using a Communication Model to Collect Measurement Data through Mobile Devices

    PubMed Central

    Bravo, José; Villarreal, Vladimir; Hervás, Ramón; Urzaiz, Gabriel

    2012-01-01

    Wireless systems and services have undergone remarkable development since the first mobile phone system was introduced in the early 1980s. The use of sensors in an Ambient Intelligence approach is a great solution in a medical environment. We define a communication architecture to facilitate the information transfer between all connected devices. This model is based in layers to allow the collection of measurement data to be used in our framework monitoring architecture. An overlay-based solution is built between network elements in order to provide an efficient and highly functional communication platform that allows the connection of a wide variety of devices and technologies, and serves also to perform additional functions such as the possibility to perform some processing in the network that may help to improve overall performance. PMID:23012542

  10. Multiscale Modelling and Analysis of Collective Decision Making in Swarm Robotics

    PubMed Central

    Vigelius, Matthias; Meyer, Bernd; Pascoe, Geoffrey

    2014-01-01

    We present a unified approach to describing certain types of collective decision making in swarm robotics that bridges from a microscopic individual-based description to aggregate properties. Our approach encompasses robot swarm experiments, microscopic and probabilistic macroscopic-discrete simulations as well as an analytic mathematical model. Following up on previous work, we identify the symmetry parameter, a measure of the progress of the swarm towards a decision, as a fundamental integrated swarm property and formulate its time evolution as a continuous-time Markov process. Contrary to previous work, which justified this approach only empirically and a posteriori, we justify it from first principles and derive hard limits on the parameter regime in which it is applicable. PMID:25369026

  11. Standardized data collection to build prediction models in oncology: a prototype for rectal cancer.

    PubMed

    Meldolesi, Elisa; van Soest, Johan; Damiani, Andrea; Dekker, Andre; Alitto, Anna Rita; Campitelli, Maura; Dinapoli, Nicola; Gatta, Roberto; Gambacorta, Maria Antonietta; Lanzotti, Vito; Lambin, Philippe; Valentini, Vincenzo

    2016-01-01

    The advances in diagnostic and treatment technology are responsible for a remarkable transformation in the internal medicine concept with the establishment of a new idea of personalized medicine. Inter- and intra-patient tumor heterogeneity and the clinical outcome and/or treatment's toxicity's complexity, justify the effort to develop predictive models from decision support systems. However, the number of evaluated variables coming from multiple disciplines: oncology, computer science, bioinformatics, statistics, genomics, imaging, among others could be very large thus making traditional statistical analysis difficult to exploit. Automated data-mining processes and machine learning approaches can be a solution to organize the massive amount of data, trying to unravel important interaction. The purpose of this paper is to describe the strategy to collect and analyze data properly for decision support and introduce the concept of an 'umbrella protocol' within the framework of 'rapid learning healthcare'. PMID:26674745

  12. Regression modeling of particle size distributions in urban storm water: advancements through improved sample collection methods

    USGS Publications Warehouse

    Fienen, Michael N.; Selbig, William R.

    2012-01-01

    A new sample collection system was developed to improve the representation of sediment entrained in urban storm water by integrating water quality samples from the entire water column. The depth-integrated sampler arm (DISA) was able to mitigate sediment stratification bias in storm water, thereby improving the characterization of suspended-sediment concentration and particle size distribution at three independent study locations. Use of the DISA decreased variability, which improved statistical regression to predict particle size distribution using surrogate environmental parameters, such as precipitation depth and intensity. The performance of this statistical modeling technique was compared to results using traditional fixed-point sampling methods and was found to perform better. When environmental parameters can be used to predict particle size distributions, environmental managers have more options when characterizing concentrations, loads, and particle size distributions in urban runoff.

  13. Multiscale modelling and analysis of collective decision making in swarm robotics.

    PubMed

    Vigelius, Matthias; Meyer, Bernd; Pascoe, Geoffrey

    2014-01-01

    We present a unified approach to describing certain types of collective decision making in swarm robotics that bridges from a microscopic individual-based description to aggregate properties. Our approach encompasses robot swarm experiments, microscopic and probabilistic macroscopic-discrete simulations as well as an analytic mathematical model. Following up on previous work, we identify the symmetry parameter, a measure of the progress of the swarm towards a decision, as a fundamental integrated swarm property and formulate its time evolution as a continuous-time Markov process. Contrary to previous work, which justified this approach only empirically and a posteriori, we justify it from first principles and derive hard limits on the parameter regime in which it is applicable.

  14. Phase transition in the collective migration of tissue cells: Experiment and model

    NASA Astrophysics Data System (ADS)

    Szabó, B.; Szöllösi, G. J.; Gönci, B.; Jurányi, Zs.; Selmeczi, D.; Vicsek, Tamás

    2006-12-01

    We have recorded the swarming-like collective migration of a large number of keratocytes (tissue cells obtained from the scales of goldfish) using long-term videomicroscopy. By increasing the overall density of the migrating cells, we have been able to demonstrate experimentally a kinetic phase transition from a disordered into an ordered state. Near the critical density a complex picture emerges with interacting clusters of cells moving in groups. Motivated by these experiments we have constructed a flocking model that exhibits a continuous transition to the ordered phase, while assuming only short-range interactions and no explicit information about the knowledge of the directions of motion of neighbors. Placing cells in microfabricated arenas we found spectacular whirling behavior which we could also reproduce in simulations.

  15. A model for improving student confidence and experience in diagnostic sample collection and interpretation.

    PubMed

    Williams, Laurel E; Nettifee-Osborne, Julie A; Johnson, Jeffrey L

    2006-01-01

    Confidence and proficiency in diagnosing and treating a variety of diseases is of obvious importance to veterinary students. Traditional teaching methods relying on live-animal laboratories or teaching-hospital cases may not provide the breadth and depth of experience necessary to promote optimal development of confidence and skills. These settings also raise concerns about expense, about animal welfare when animals are used in teaching laboratories, and about the stress and potential risks associated with client-owned pets in the teaching hospital. A one-week course implemented in our veterinary curriculum provides the opportunity for students to develop self-assurance and experience in sample collection and interpretation skills in a realistic, clinical-model setting. This course provides students with significantly improved levels of confidence when performing procedures and interpreting results from a variety of procedures and helps prepare them to become clinicians entering the practice of veterinary medicine. PMID:16767653

  16. Standardized data collection to build prediction models in oncology: a prototype for rectal cancer.

    PubMed

    Meldolesi, Elisa; van Soest, Johan; Damiani, Andrea; Dekker, Andre; Alitto, Anna Rita; Campitelli, Maura; Dinapoli, Nicola; Gatta, Roberto; Gambacorta, Maria Antonietta; Lanzotti, Vito; Lambin, Philippe; Valentini, Vincenzo

    2016-01-01

    The advances in diagnostic and treatment technology are responsible for a remarkable transformation in the internal medicine concept with the establishment of a new idea of personalized medicine. Inter- and intra-patient tumor heterogeneity and the clinical outcome and/or treatment's toxicity's complexity, justify the effort to develop predictive models from decision support systems. However, the number of evaluated variables coming from multiple disciplines: oncology, computer science, bioinformatics, statistics, genomics, imaging, among others could be very large thus making traditional statistical analysis difficult to exploit. Automated data-mining processes and machine learning approaches can be a solution to organize the massive amount of data, trying to unravel important interaction. The purpose of this paper is to describe the strategy to collect and analyze data properly for decision support and introduce the concept of an 'umbrella protocol' within the framework of 'rapid learning healthcare'.

  17. When the association between appearance and outcome contaminates social judgment: a bidirectional model linking group homogeneity and collective treatment.

    PubMed

    Alter, Adam L; Darley, John M

    2009-11-01

    Group formation is an inevitable consequence of social life, and the tendency to perceive people as a collective unit persists once they have been categorized as a group. Drawing on the concept of homogeneity, the authors propose a model suggesting that groups may endure in part because people who are perceived as homogeneous attract collective treatment (e.g., monetary rewards and punishment), and such treatment further reinforces the perception that the group's members are homogeneous. In support of this model, more homogeneous groups attracted collective treatment and collectively treated groups seemed to be more homogeneous thereafter. The authors suggest that these effects arise in part because people intuitively believe that group homogeneity is associated with collective treatment, and they present evidence suggesting that this applies to at least one policy-relevant real-world setting. PMID:19857001

  18. Collecting Protein Biomarkers in Breath Using Electret Filters: A Preliminary Method on New Technical Model and Human Study.

    PubMed

    Li, Wang; Pi, Xitian; Qiao, Panpan; Liu, Hongying

    2016-01-01

    Biomarkers in exhaled breath are useful for respiratory disease diagnosis in human volunteers. Conventional methods that collect non-volatile biomarkers, however, necessitate an extensive dilution and sanitation processes that lowers collection efficiencies and convenience of use. Electret filter emerged in recent decade to collect virus biomarkers in exhaled breath given its simplicity and effectiveness. To investigate the capability of electret filters to collect protein biomarkers, a model that consists of an atomizer that produces protein aerosol and an electret filter that collects albumin and carcinoembryonic antigen-a typical biomarker in lung cancer development- from the atomizer is developed. A device using electret filter as the collecting medium is designed to collect human albumin from exhaled breath of 6 volunteers. Comparison of the collecting ability between the electret filter method and other 2 reported methods is finally performed based on the amounts of albumin collected from human exhaled breath. In conclusion, a decreasing collection efficiency ranging from 17.6% to 2.3% for atomized albumin aerosol and 42% to 12.5% for atomized carcinoembryonic antigen particles is found; moreover, an optimum volume of sampling human exhaled breath ranging from 100 L to 200 L is also observed; finally, the self-designed collecting device shows a significantly better performance in collecting albumin from human exhaled breath than the exhaled breath condensate method (p<0.05) but is not significantly more effective than reported 3-stage impactor method (p>0.05). In summary, electret filters are potential in collecting non-volatile biomarkers in human exhaled breath not only because it was simpler, cheaper and easier to use than traditional methods but also for its better collecting performance.

  19. Collecting Protein Biomarkers in Breath Using Electret Filters: A Preliminary Method on New Technical Model and Human Study

    PubMed Central

    Li, Wang; Pi, Xitian; Qiao, Panpan; Liu, Hongying

    2016-01-01

    Biomarkers in exhaled breath are useful for respiratory disease diagnosis in human volunteers. Conventional methods that collect non-volatile biomarkers, however, necessitate an extensive dilution and sanitation processes that lowers collection efficiencies and convenience of use. Electret filter emerged in recent decade to collect virus biomarkers in exhaled breath given its simplicity and effectiveness. To investigate the capability of electret filters to collect protein biomarkers, a model that consists of an atomizer that produces protein aerosol and an electret filter that collects albumin and carcinoembryonic antigen-a typical biomarker in lung cancer development- from the atomizer is developed. A device using electret filter as the collecting medium is designed to collect human albumin from exhaled breath of 6 volunteers. Comparison of the collecting ability between the electret filter method and other 2 reported methods is finally performed based on the amounts of albumin collected from human exhaled breath. In conclusion, a decreasing collection efficiency ranging from 17.6% to 2.3% for atomized albumin aerosol and 42% to 12.5% for atomized carcinoembryonic antigen particles is found; moreover, an optimum volume of sampling human exhaled breath ranging from 100 L to 200 L is also observed; finally, the self-designed collecting device shows a significantly better performance in collecting albumin from human exhaled breath than the exhaled breath condensate method (p<0.05) but is not significantly more effective than reported 3-stage impactor method (p>0.05). In summary, electret filters are potential in collecting non-volatile biomarkers in human exhaled breath not only because it was simpler, cheaper and easier to use than traditional methods but also for its better collecting performance. PMID:26934615

  20. Collective properties of injection-induced earthquake sequences: 1. Model description and directivity bias

    NASA Astrophysics Data System (ADS)

    Dempsey, David; Suckale, Jenny

    2016-05-01

    Induced seismicity is of increasing concern for oil and gas, geothermal, and carbon sequestration operations, with several M > 5 events triggered in recent years. Modeling plays an important role in understanding the causes of this seismicity and in constraining seismic hazard. Here we study the collective properties of induced earthquake sequences and the physics underpinning them. In this first paper of a two-part series, we focus on the directivity ratio, which quantifies whether fault rupture is dominated by one (unilateral) or two (bilateral) propagating fronts. In a second paper, we focus on the spatiotemporal and magnitude-frequency distributions of induced seismicity. We develop a model that couples a fracture mechanics description of 1-D fault rupture with fractal stress heterogeneity and the evolving pore pressure distribution around an injection well that triggers earthquakes. The extent of fault rupture is calculated from the equations of motion for two tips of an expanding crack centered at the earthquake hypocenter. Under tectonic loading conditions, our model exhibits a preference for unilateral rupture and a normal distribution of hypocenter locations, two features that are consistent with seismological observations. On the other hand, catalogs of induced events when injection occurs directly onto a fault exhibit a bias toward ruptures that propagate toward the injection well. This bias is due to relatively favorable conditions for rupture that exist within the high-pressure plume. The strength of the directivity bias depends on a number of factors including the style of pressure buildup, the proximity of the fault to failure and event magnitude. For injection off a fault that triggers earthquakes, the modeled directivity bias is small and may be too weak for practical detection. For two hypothetical injection scenarios, we estimate the number of earthquake observations required to detect directivity bias.

  1. Collective behavior and predation success in a predator-prey model inspired by hunting bats.

    PubMed

    Lin, Yuan; Abaid, Nicole

    2013-12-01

    We establish an agent-based model to study the impact of prey behavior on the hunting success of predators. The predators and prey are modeled as self-propelled particles moving in a three-dimensional domain and subject to specific sensing abilities and behavioral rules inspired by bat hunting. The predators randomly search for prey. The prey either align velocity directions with peers, defined as "interacting" prey, or swarm "independently" of peer presence; both types of prey are subject to additive noise. In a simulation study, we find that interacting prey using low noise have the maximum predation avoidance because they form localized large groups, while they suffer high predation as noise increases due to the formation of broadly dispersed small groups. Independent prey, which are likely to be uniformly distributed in the domain, have higher predation risk under a low noise regime as they traverse larger spatial extents. These effects are enhanced in large prey populations, which exhibit more ordered collective behavior or more uniform spatial distribution as they are interacting or independent, respectively.

  2. Universal model for collective access patterns in the Internet traffic dynamics: A superstatistical approach

    NASA Astrophysics Data System (ADS)

    Tamazian, A.; Nguyen, V. D.; Markelov, O. A.; Bogachev, M. I.

    2016-07-01

    We suggest a universal phenomenological description for the collective access patterns in the Internet traffic dynamics both at local and wide area network levels that takes into account erratic fluctuations imposed by cooperative user behaviour. Our description is based on the superstatistical approach and leads to the q-exponential inter-session time and session size distributions that are also in perfect agreement with empirical observations. The validity of the proposed description is confirmed explicitly by the analysis of complete 10-day traffic traces from the WIDE backbone link and from the local campus area network downlink from the Internet Service Provider. Remarkably, the same functional forms have been observed in the historic access patterns from single WWW servers. The suggested approach effectively accounts for the complex interplay of both “calm” and “bursty” user access patterns within a single-model setting. It also provides average sojourn time estimates with reasonable accuracy, as indicated by the queuing system performance simulation, this way largely overcoming the failure of Poisson modelling of the Internet traffic dynamics.

  3. Modeling the Transitions between Collective and Solitary Migration Phenotypes in Cancer Metastasis

    NASA Astrophysics Data System (ADS)

    Huang, Bin; Jolly, Mohit Kumar; Lu, Mingyang; Tsarfaty, Ilan; Ben-Jacob, Eshel; Onuchic, Jose' N.

    2015-12-01

    Cellular plasticity during cancer metastasis is a major clinical challenge. Two key cellular plasticity mechanisms —Epithelial-to-Mesenchymal Transition (EMT) and Mesenchymal-to-Amoeboid Transition (MAT) - have been carefully investigated individually, yet a comprehensive understanding of their interconnections remains elusive. Previously, we have modeled the dynamics of the core regulatory circuits for both EMT (miR-200/ZEB/miR-34/SNAIL) and MAT (Rac1/RhoA). We now extend our previous work to study the coupling between these two core circuits by considering the two microRNAs (miR-200 and miR-34) as external signals to the core MAT circuit. We show that this coupled circuit enables four different stable steady states (phenotypes) that correspond to hybrid epithelial/mesenchymal (E/M), mesenchymal (M), amoeboid (A) and hybrid amoeboid/mesenchymal (A/M) phenotypes. Our model recapitulates the metastasis-suppressing role of the microRNAs even in the presence of EMT-inducing signals like Hepatocyte Growth Factor (HGF). It also enables mapping the microRNA levels to the transitions among various cell migration phenotypes. Finally, it offers a mechanistic understanding for the observed phenotypic transitions among different cell migration phenotypes, specifically the Collective-to-Amoeboid Transition (CAT).

  4. Collective behavior and predation success in a predator-prey model inspired by hunting bats

    NASA Astrophysics Data System (ADS)

    Lin, Yuan; Abaid, Nicole

    2013-12-01

    We establish an agent-based model to study the impact of prey behavior on the hunting success of predators. The predators and prey are modeled as self-propelled particles moving in a three-dimensional domain and subject to specific sensing abilities and behavioral rules inspired by bat hunting. The predators randomly search for prey. The prey either align velocity directions with peers, defined as "interacting" prey, or swarm "independently" of peer presence; both types of prey are subject to additive noise. In a simulation study, we find that interacting prey using low noise have the maximum predation avoidance because they form localized large groups, while they suffer high predation as noise increases due to the formation of broadly dispersed small groups. Independent prey, which are likely to be uniformly distributed in the domain, have higher predation risk under a low noise regime as they traverse larger spatial extents. These effects are enhanced in large prey populations, which exhibit more ordered collective behavior or more uniform spatial distribution as they are interacting or independent, respectively.

  5. Assessing Historical Fish Community Composition Using Surveys, Historical Collection Data, and Species Distribution Models

    PubMed Central

    Labay, Ben; Cohen, Adam E.; Sissel, Blake; Hendrickson, Dean A.; Martin, F. Douglas; Sarkar, Sahotra

    2011-01-01

    Accurate establishment of baseline conditions is critical to successful management and habitat restoration. We demonstrate the ability to robustly estimate historical fish community composition and assess the current status of the urbanized Barton Creek watershed in central Texas, U.S.A. Fish species were surveyed in 2008 and the resulting data compared to three sources of fish occurrence information: (i) historical records from a museum specimen database and literature searches; (ii) a nearly identical survey conducted 15 years earlier; and (iii) a modeled historical community constructed with species distribution models (SDMs). This holistic approach, and especially the application of SDMs, allowed us to discover that the fish community in Barton Creek was more diverse than the historical data and survey methods alone indicated. Sixteen native species with high modeled probability of occurrence within the watershed were not found in the 2008 survey, seven of these were not found in either survey or in any of the historical collection records. Our approach allowed us to more rigorously establish the true baseline for the pre-development fish fauna and then to more accurately assess trends and develop hypotheses regarding factors driving current fish community composition to better inform management decisions and future restoration efforts. Smaller, urbanized freshwater systems, like Barton Creek, typically have a relatively poor historical biodiversity inventory coupled with long histories of alteration, and thus there is a propensity for land managers and researchers to apply inaccurate baseline standards. Our methods provide a way around that limitation by using SDMs derived from larger and richer biodiversity databases of a broader geographic scope. Broadly applied, we propose that this technique has potential to overcome limitations of popular bioassessment metrics (e.g., IBI) to become a versatile and robust management tool for determining status of

  6. Enabling School Structure, Collective Responsibility, and a Culture of Academic Optimism: Toward a Robust Model of School Performance in Taiwan

    ERIC Educational Resources Information Center

    Wu, Jason H.; Hoy, Wayne K.; Tarter, C. John

    2013-01-01

    Purpose: The purpose of this research is twofold: to test a theory of academic optimism in Taiwan elementary schools and to expand the theory by adding new variables, collective responsibility and enabling school structure, to the model. Design/methodology/approach: Structural equation modeling was used to test, refine, and expand an…

  7. Regulation of K transport in a mathematical model of the cortical collecting tubule.

    PubMed

    Strieter, J; Weinstein, A M; Giebisch, G; Stephenson, J L

    1992-12-01

    The effect of luminal flow rate and peritubular pH on Na and K transport is investigated in a mathematical model of the rabbit cortical collecting tubule. The model is used to simulate a 0.4-cm segment of tubule comprised of principal cell, alpha- and beta-intercalated cells, and lateral interspace. Calculations produce luminal profiles of Na, K, Cl, HCO3, and phosphate, as well as of electrical potential and pH. Parameter sets are developed that permit representation of both unstimulated and deoxycorticosterone acetate-stimulated tubules. A series of simulations is performed in which initial luminal flow rate is varied over the range of values between 0.1 and 30 nl/min. A marked flow-dependent enhancement of Na reabsorption and K secretion is seen, especially at lower flows, while Cl and HCO3 transport remain relatively constant. In experimental studies, it has been observed that metabolic alkalosis stimulates and metabolic acidosis inhibits K secretion, while leaving Na transport relatively unaffected [B. A. Stanton and G. Giebisch. Am. J. Physiol. 242 (Renal Fluid Electrolyte Physiol. 11): F544-F551, 1982; K. Tabei, S. Muto, Y. Ando, Y. Sakairi, and Y. Asano. J. Am. Soc. Nephrol. 1: 693, 1990; and K. Tabei, S. Muto, H. Furuya, and Y. Asano. J. Am. Soc. Nephrol. 2: 752, 1991]. Model calculations indicate that, when ion permeabilities are fixed and not dependent on pH, the impact of peritubular HCO3 on K secretion cannot be simulated. When junctional Cl permeability decreases with increasing interspace pH (E. M. Wright and J. M. Diamond. Biochim. Biophys. Acta 163: 57-74, 1968) in the model, there is a marked stimulation of K secretion with alkalosis and inhibition with acidosis. Furthermore, inclusion of a pH-dependent apical Na permeability [L. G. Palmer and G. Frindt. Am. J. Physiol. 253 (Renal Fluid Electrolyte Physiol. 22): F333-F339, 1987] that increases with increasing principal cell pH significantly reduces the change in Na+ reabsorption seen with the p

  8. Data-collection program for Pamlico River Estuary model calibration and validation

    USGS Publications Warehouse

    Bales, Jerad D.

    1989-01-01

    An investigation is being conducted to collect and interpret continuous records relating to the flow characteristics of the Pamlico River Estuary, North Carolina, and to calibrate and validate a numerical model of estuarine hydrodynamics. The study reach is 50 kilometers long and ranges in width from 330 meters at the upstream boundary to 6.4 kilometers at the downstream end. Water levels are recorded at 6 locations along the estuary; daily water-level range is typically greater at the head of the estuary than at the mouth, most likely due to upstream narrowing of the channel. Water-quality data are recorded at 14 locations. These data indicate that saline waters with low dissolved oxygen concentrations move upstream along the bottom of the estuary. Point velocities were monitored for 3 weeks at 7 locations; vertical profiles of horizontal velocity were made at the boundaries of the study reach for about 32 hours. Local tributary inflows and wind speed and direction are also being determined.

  9. Tavis-Cummings model and collective multiqubit entanglement in trapped ions

    SciTech Connect

    Retzker, A.; Solano, E.; Reznik, B.

    2007-02-15

    We present a method of generating collective multiqubit entanglement via global addressing of an ion chain performing blue and red Tavis-Cummings interactions, where several qubits are coupled to a collective motional mode. We show that a wide family of Dicke states and irradiant states can be generated by single global laser pulses, unitarily or helped with suitable postselection techniques.

  10. Model wave functions for the collective modes and the magnetoroton theory of the fractional quantum Hall effect.

    PubMed

    Yang, Bo; Hu, Zi-Xiang; Papić, Z; Haldane, F D M

    2012-06-22

    We construct model wave functions for the collective modes of fractional quantum Hall systems. The wave functions are expressed in terms of symmetric polynomials characterized by a root partition that defines a "squeezed" basis, and show excellent agreement with exact diagonalization results for finite systems. In the long wavelength limit, we prove that the model wave functions are identical to those predicted by the single-mode approximation, leading to intriguing interpretations of the collective modes from the perspective of the ground-state guiding-center metric.

  11. Modelling informally collected quantities of bulky waste and reusable items in Austria

    SciTech Connect

    Ramusch, R. Pertl, A.; Scherhaufer, S.; Schmied, E.; Obersteiner, G.

    2015-10-15

    Highlights: • Informal collectors from Hungary collect bulky waste and reusable items in Austria. • Two methodologies were applied to estimate the informally collected quantities. • Both approaches lead to an estimation of roughly 100,000 t p.a. informally collected. • The formal Austrian system collects 72 kg/cap/yr of bulky waste, WEE & scrap metal. • Informal collection amounts to approx. 12 kg/cap/yr. - Abstract: Disparities in earnings between Western and Eastern European countries are the reason for a well-established informal sector actively involved in collection and transboundary shipment activities from Austria to Hungary. The preferred objects are reusable items and wastes within the categories bulky waste, WEEE and metals, intended to be sold on flea markets. Despite leading to a loss of recyclable resources for Austrian waste management, these informal activities may contribute to the extension of the lifetime of certain goods when they are reused in Hungary; nevertheless they are discussed rather controversially. The aim of this paper is to provide objective data on the quantities informally collected and transhipped. The unique activities of informal collectors required the development and implementation of a new set of methodologies. The concept of triangulation was used to verify results obtained by field visits, interviews and a traffic counting campaign. Both approaches lead to an estimation of approx. 100,000 t per year of reusable items informally collected in Austria. This means that in addition to the approx. 72 kg/cap/yr formally collected bulky waste, bulky waste wood, household scrap (excluding packaging) and WEEE, up to a further 12 kg/cap/yr might, in the case that informal collection is abandoned, end up as waste or in the second-hand sector.

  12. Development of a multicriteria assessment model for ranking biomass feedstock collection and transportation systems.

    PubMed

    Kumar, Amit; Sokhansanj, Shahab; Flynn, Peter C

    2006-01-01

    This study details multicriteria assessment methodology that integrates economic, social, environmental, and technical factors in order to rank alternatives for biomass collection and transportation systems. Ranking of biomass collection systems is based on cost of delivered biomass, quality of biomass supplied, emissions during collection, energy input to the chain operations, and maturity of supply system technologies. The assessment methodology is used to evaluate alternatives for collecting 1.8 x 10(6) dry t/yr based on assumptions made on performance of various assemblies of biomass collection systems. A proposed collection option using loafer/ stacker was shown to be the best option followed by ensiling and baling. Ranking of biomass transport systems is based on cost of biomass transport, emissions during transport, traffic congestion, and maturity of different technologies. At a capacity of 4 x 10(6) dry t/yr, rail transport was shown to be the best option, followed by truck transport and pipeline transport, respectively. These rankings depend highly on assumed maturity of technologies and scale of utilization. These may change if technologies such as loafing or ensiling (wet storage) methods are proved to be infeasible for large-scale collection systems. PMID:16915632

  13. A Collective Case Study of Secondary Students' Model-Based Inquiry on Natural Selection through Programming in an Agent-Based Modeling Environment

    ERIC Educational Resources Information Center

    Xiang, Lin

    2011-01-01

    This is a collective case study seeking to develop detailed descriptions of how programming an agent-based simulation influences a group of 8th grade students' model-based inquiry (MBI) by examining students' agent-based programmable modeling (ABPM) processes and the learning outcomes. The context of the present study was a biology unit on…

  14. EVALUATION OF SEVERAL PM 2.5 FORECAST MODELS USING DATA COLLECTED DURING THE ICARTT/NEAQS 2004 FIELD STUDY

    EPA Science Inventory

    Real-time forecasts of PM2.5 aerosol mass from seven air-quality forecast models (AQFMs) are statistically evaluated against observations collected in the northeastern U.S. and southeastern Canada from two surface networks and aircraft data during the summer of 2004 IC...

  15. Data collection for cooperative water resources modeling in the Lower Rio Grande Basin, Fort Quitman to the Gulf of Mexico.

    SciTech Connect

    Passell, Howard David; Pallachula, Kiran; Tidwell, Vincent Carroll; Villalobos, Joshua; Piccinni, Giovanni; Brainard, James Robert; Gerik, Thomas; Morrison, Wendy; Serrat-Capdevila, Aleix; Valdes, Juan; Sheng, Zhuping; Lovato, Rene; Guitron, Alberto; Ennis, Martha Lee; Aparicio, Javier; Newman, Gretchen Carr; Michelsen, Ari M.

    2004-10-01

    Water resource scarcity around the world is driving the need for the development of simulation models that can assist in water resources management. Transboundary water resources are receiving special attention because of the potential for conflict over scarce shared water resources. The Rio Grande/Rio Bravo along the U.S./Mexican border is an example of a scarce, transboundary water resource over which conflict has already begun. The data collection and modeling effort described in this report aims at developing methods for international collaboration, data collection, data integration and modeling for simulating geographically large and diverse international watersheds, with a special focus on the Rio Grande/Rio Bravo. This report describes the basin, and the data collected. This data collection effort was spatially aggregated across five reaches consisting of Fort Quitman to Presidio, the Rio Conchos, Presidio to Amistad Dam, Amistad Dam to Falcon Dam, and Falcon Dam to the Gulf of Mexico. This report represents a nine-month effort made in FY04, during which time the model was not completed.

  16. Modelling informally collected quantities of bulky waste and reusable items in Austria.

    PubMed

    Ramusch, R; Pertl, A; Scherhaufer, S; Schmied, E; Obersteiner, G

    2015-10-01

    Disparities in earnings between Western and Eastern European countries are the reason for a well-established informal sector actively involved in collection and transboundary shipment activities from Austria to Hungary. The preferred objects are reusable items and wastes within the categories bulky waste, WEEE and metals, intended to be sold on flea markets. Despite leading to a loss of recyclable resources for Austrian waste management, these informal activities may contribute to the extension of the lifetime of certain goods when they are reused in Hungary; nevertheless they are discussed rather controversially. The aim of this paper is to provide objective data on the quantities informally collected and transhipped. The unique activities of informal collectors required the development and implementation of a new set of methodologies. The concept of triangulation was used to verify results obtained by field visits, interviews and a traffic counting campaign. Both approaches lead to an estimation of approx. 100,000 t per year of reusable items informally collected in Austria. This means that in addition to the approx. 72 kg/cap/yr formally collected bulky waste, bulky waste wood, household scrap (excluding packaging) and WEEE, up to a further 12 kg/cap/yr might, in the case that informal collection is abandoned, end up as waste or in the second-hand sector. PMID:26209344

  17. Modelling informally collected quantities of bulky waste and reusable items in Austria.

    PubMed

    Ramusch, R; Pertl, A; Scherhaufer, S; Schmied, E; Obersteiner, G

    2015-10-01

    Disparities in earnings between Western and Eastern European countries are the reason for a well-established informal sector actively involved in collection and transboundary shipment activities from Austria to Hungary. The preferred objects are reusable items and wastes within the categories bulky waste, WEEE and metals, intended to be sold on flea markets. Despite leading to a loss of recyclable resources for Austrian waste management, these informal activities may contribute to the extension of the lifetime of certain goods when they are reused in Hungary; nevertheless they are discussed rather controversially. The aim of this paper is to provide objective data on the quantities informally collected and transhipped. The unique activities of informal collectors required the development and implementation of a new set of methodologies. The concept of triangulation was used to verify results obtained by field visits, interviews and a traffic counting campaign. Both approaches lead to an estimation of approx. 100,000 t per year of reusable items informally collected in Austria. This means that in addition to the approx. 72 kg/cap/yr formally collected bulky waste, bulky waste wood, household scrap (excluding packaging) and WEEE, up to a further 12 kg/cap/yr might, in the case that informal collection is abandoned, end up as waste or in the second-hand sector.

  18. Collective migration models: Dynamic monitoring of leader cells in migratory/invasive disease processes

    NASA Astrophysics Data System (ADS)

    Dean, Zachary Steven

    Leader cells are a fundamental biological process that have only been investigated since the early 2000s. These cells have often been observed emerging at the edge of an artificial wound in 2D epithelial cell collective invasion, created with either a mechanical scrape from a pipette tip or from the removal of a plastic, physical blocker. During migration, the moving cells maintain cell-cell contacts, an important quality of collective migration; the leader cells originate from either the first or the second row, they increase in size compared to other cells, and they establish ruffled lamellipodia. Recent studies in 3D have also shown that cells emerging from an invading collective group that also exhibit leader-like properties. Exactly how leader cells influence and interact with follower cells as well as other cells types during collective migration, however, is another matter, and is a subject of intense investigation between many different labs and researchers. The majority of leader cell research to date has involved epithelial cells, but as collective migration is implicated in many different pathogenic diseases, such as cancer and wound healing, a better understanding of leader cells in many cell types and environments will allow significant improvement to therapies and treatments for a wide variety of disease processes. In fact, more recent studies on collective migration and invasion have broadened the field to include other cell types, including mesenchymal cancer cells and fibroblasts. However, the proper technology for picking out dynamic, single cells within a moving and changing cell population over time has severely limited previous investigation into leader cell formation and influence over other cells. In line with these previous studies, we not only bring new technology capable of dynamically monitoring leader cell formation, but we propose that leader cell behavior is more than just an epithelial process, and that it is a critical physiological

  19. 75 FR 34767 - Proposed Information Collection Request of the Resource Justification Model (RJM); Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-18

    ... actual Unemployment Insurance (UI) administrative cost data from states' accounting records and projected... functional activity and two years of projected expenditures. The actual cost data informs ETA's... responses. III. Current Actions The data collected within the RJM state submissions are used as input to...

  20. Creation of a Knowledge City in Educational Institutions: A Model for Promoting Teachers' Collective Capacity Building

    ERIC Educational Resources Information Center

    Konidari, Victoria; Abernot, Yvan

    2007-01-01

    The aim of this paper is to outline a theoretical and methodological framework for the understanding, design and creation of teachers' collective capacity through the implementation of knowledge cities in educational institutions which are registered in the context of a fourth generation of Knowledge Management. The authors suggest four pillars on…

  1. Combinatoric Models of Information Retrieval Ranking Methods and Performance Measures for Weakly-Ordered Document Collections

    ERIC Educational Resources Information Center

    Church, Lewis

    2010-01-01

    This dissertation answers three research questions: (1) What are the characteristics of a combinatoric measure, based on the Average Search Length (ASL), that performs the same as a probabilistic version of the ASL?; (2) Does the combinatoric ASL measure produce the same performance result as the one that is obtained by ranking a collection of…

  2. Collection Fusion Using Bayesian Estimation of a Linear Regression Model in Image Databases on the Web.

    ERIC Educational Resources Information Center

    Kim, Deok-Hwan; Chung, Chin-Wan

    2003-01-01

    Discusses the collection fusion problem of image databases, concerned with retrieving relevant images by content based retrieval from image databases distributed on the Web. Focuses on a metaserver which selects image databases supporting similarity measures and proposes a new algorithm which exploits a probabilistic technique using Bayesian…

  3. Performance Standards and Evaluations in IR Test Collections: Cluster-Based Retrieval Models.

    ERIC Educational Resources Information Center

    Shaw, W. M., Jr.; And Others

    1997-01-01

    Describes a study that computed low performance standards for the group of queries in 13 information retrieval (IR) test collections. Derived from the random graph hypothesis, these standards represent the highest levels of retrieval effectiveness that can be obtained from meaningless clustering structures. (Author/LRW)

  4. Building a bridge with the customer to facilitate collecting and validating information in modeling sessions

    SciTech Connect

    Eaton, S.M.

    1994-07-21

    To build a bridge with customers, we balance the linear modeling process with the dynamics of the individuals we serve, who may feel unfamiliar, even confused, with that process. While it is recognized that human factors engineers improve the physical aspect of the workplace, they also work to integrate customers` cognitive styles, feelings, and concerns into the workplace tools. We take customers` feelings into consideration and integrate their expressed needs and concerns into the modeling sessions. After establishing an agreeable, professional relationship, we use a simple, portable CASE tool to reveal the effectiveness of NIAM. This tool, Modeler`s Assistant, is friendly enough to use directly with people who know nothing of NIAM, yet it captures all the information necessary to create complete models. The Modeler`s Assistant succeeds because it organizes the detailed information in an enhanced text format for customer validation. Customer cooperation results from our modeling sessions as they grow comfortable and become enthused about providing information.

  5. Non-collective Parallel I/O for Global Address Space Programming Models

    SciTech Connect

    Krishnamoorthy, Sriram; Piernas Canovas, Juan; Tipparaju, Vinod; Nieplocha, Jaroslaw; Sadayappan, Ponnuswamy

    2007-09-13

    Achieving high performance for out-of-core applications typically involves explicit management of the movement of data between the disk and the physical memory. We are developing a programming environment in which the different levels of the memory hierarchy are handled efficiently in a unified transparent framework. In this paper, we present our experiences with implementing efficient non-collective I/O (GPC-IO) as part of this framework. As a generalization of the Remote Procedure Call (RPC) that was used as a foundation for the Sun NFS system, we developed a global procedure call (GPC) to invoke procedures on a remote node to handle non-collective I/O. We consider alternative approaches that can be employed in implementing this functionality. The approaches are evaluated using a representative computation from quantum chemistry. The results demonstrate that GPC-IO achieves better absolute execution times, strong-scaling, and weakscaling than the alternatives considered.

  6. Mechanism to support generic collective communication across a variety of programming models

    DOEpatents

    Almasi, Gheorghe; Dozsa, Gabor; Kumar, Sameer

    2011-07-19

    A system and method for supporting collective communications on a plurality of processors that use different parallel programming paradigms, in one aspect, may comprise a schedule defining one or more tasks in a collective operation, an executor that executes the task, a multisend module to perform one or more data transfer functions associated with the tasks, and a connection manager that controls one or more connections and identifies an available connection. The multisend module uses the available connection in performing the one or more data transfer functions. A plurality of processors that use different parallel programming paradigms can use a common implementation of the schedule module, the executor module, the connection manager and the multisend module via a language adaptor specific to a parallel programming paradigm implemented on a processor.

  7. Mass collecting and the diet breadth model: A Great Basin example

    USGS Publications Warehouse

    Madsen, D.B.; Schmitt, D.N.

    1998-01-01

    The energetic return rates of many small animal and plant resources are often density dependent. When these resources are collected in mass, change in abundance can dramatically affect diet rank, and challenges the assumption that return rates are generally correlated with body size. When mass collecting is employed, as a result of either natural events (e.g. windrows) or technological developments (e.g. nets), population density may largely determine the overall return rate for a resource. Since a single food or resource type can be many prey types, an increase in the abundance of a food resource can change its diet rank. We examined this relationship at Lakeside Cave in northwestern Utah, and discovered that when the abundance of grasshoppers is high, and mass collecting is productive, the hunting of bighorn sheep and other large animal resources may have been abandoned, contradicting commonly held assumptions about prey size. In archaeological situations it may be necessary to determine what foraging technique was used before assuming that the presence of small animals and fish in the diet is a result of reduced foraging efficiency. ?? 1998 Academic Press Limited.

  8. Collection efficiency model based on boundary-layer characteristics for cyclones

    SciTech Connect

    Kim, W.S.; Lee, J.W.

    1997-10-01

    In cyclones, the boundary layer formed on the collecting-wall surface acts as a barrier for particle migration toward the wall due to a decreased centrifugal force on particles inside the boundary layer. A new theory for high-efficiency cyclones based on the boundary-layer characteristics is presented. The cyclone was divided into two regions: the turbulent-core region where the centrifugal force is large, and the near-wall region where the centrifugal force is small. Particle trajectories in the turbulent-core region are calculated from the mean fluid motion based on the quasi-steady drag assumption, and the collection probability of particles in the near-wall region is calculated by the deposition velocity that results from both turbulent diffusion and centrifugal force. The deposition velocity by centrifugal force was assumed equal to the equilibrium migration velocity at a certain point inside the boundary layer, and the distance to that point from the wall is assumed to be linearly proportional to the dimensionless-particle relaxation time. When the proportional constant was determined by fitting the theoretical results to experimental data, the theory showed an excellent enhancement in predicting the variation of collection efficiency with the inlet flow velocity and particle size.

  9. Modeling and enhanced sampling of molecular systems with smooth and nonlinear data-driven collective variables

    NASA Astrophysics Data System (ADS)

    Hashemian, Behrooz; Millán, Daniel; Arroyo, Marino

    2013-12-01

    Collective variables (CVs) are low-dimensional representations of the state of a complex system, which help us rationalize molecular conformations and sample free energy landscapes with molecular dynamics simulations. Given their importance, there is need for systematic methods that effectively identify CVs for complex systems. In recent years, nonlinear manifold learning has shown its ability to automatically characterize molecular collective behavior. Unfortunately, these methods fail to provide a differentiable function mapping high-dimensional configurations to their low-dimensional representation, as required in enhanced sampling methods. We introduce a methodology that, starting from an ensemble representative of molecular flexibility, builds smooth and nonlinear data-driven collective variables (SandCV) from the output of nonlinear manifold learning algorithms. We demonstrate the method with a standard benchmark molecule, alanine dipeptide, and show how it can be non-intrusively combined with off-the-shelf enhanced sampling methods, here the adaptive biasing force method. We illustrate how enhanced sampling simulations with SandCV can explore regions that were poorly sampled in the original molecular ensemble. We further explore the transferability of SandCV from a simpler system, alanine dipeptide in vacuum, to a more complex system, alanine dipeptide in explicit water.

  10. Modeling and enhanced sampling of molecular systems with smooth and nonlinear data-driven collective variables.

    PubMed

    Hashemian, Behrooz; Millán, Daniel; Arroyo, Marino

    2013-12-01

    Collective variables (CVs) are low-dimensional representations of the state of a complex system, which help us rationalize molecular conformations and sample free energy landscapes with molecular dynamics simulations. Given their importance, there is need for systematic methods that effectively identify CVs for complex systems. In recent years, nonlinear manifold learning has shown its ability to automatically characterize molecular collective behavior. Unfortunately, these methods fail to provide a differentiable function mapping high-dimensional configurations to their low-dimensional representation, as required in enhanced sampling methods. We introduce a methodology that, starting from an ensemble representative of molecular flexibility, builds smooth and nonlinear data-driven collective variables (SandCV) from the output of nonlinear manifold learning algorithms. We demonstrate the method with a standard benchmark molecule, alanine dipeptide, and show how it can be non-intrusively combined with off-the-shelf enhanced sampling methods, here the adaptive biasing force method. We illustrate how enhanced sampling simulations with SandCV can explore regions that were poorly sampled in the original molecular ensemble. We further explore the transferability of SandCV from a simpler system, alanine dipeptide in vacuum, to a more complex system, alanine dipeptide in explicit water. PMID:24320358

  11. A Model Using Local Weather Data to Determine the Effective Sampling Volume for PCB Congeners Collected on Passive Air Samplers.

    PubMed

    Herkert, Nicholas J; Martinez, Andres; Hornbuckle, Keri C

    2016-07-01

    We have developed and evaluated a mathematical model to determine the effective sampling volumes (Veff) of PCBs and similar compounds captured using polyurethane foam passive air samplers (PUF-PAS). We account for the variability in wind speed, air temperature, and equilibrium partitioning over the course of the deployment of the samplers. The model, provided as an annotated Matlab script, predicts the Veff as a function of physical-chemical properties of each compound and meteorology from the closest Integrated Surface Database (ISD) data set obtained through NOAA's National Centers for Environmental Information (NCEI). The model was developed to be user-friendly, only requiring basic Matlab knowledge. To illustrate the effectiveness of the model, we evaluated three independent data sets of airborne PCBs simultaneously collected using passive and active samplers: at sites in Chicago, Lancaster, UK, and Toronto, Canada. The model provides Veff values comparable to those using depuration compounds and calibration against active samplers, yielding an average congener specific concentration method ratio (active/passive) of 1.1 ± 1.2. We applied the model to PUF-PAS samples collected in Chicago and show that previous methods can underestimate concentrations of PCBs by up to 40%, especially for long deployments, deployments conducted under warming conditions, and compounds with log Koa values less than 8.

  12. A Model Using Local Weather Data to Determine the Effective Sampling Volume for PCB Congeners Collected on Passive Air Samplers.

    PubMed

    Herkert, Nicholas J; Martinez, Andres; Hornbuckle, Keri C

    2016-07-01

    We have developed and evaluated a mathematical model to determine the effective sampling volumes (Veff) of PCBs and similar compounds captured using polyurethane foam passive air samplers (PUF-PAS). We account for the variability in wind speed, air temperature, and equilibrium partitioning over the course of the deployment of the samplers. The model, provided as an annotated Matlab script, predicts the Veff as a function of physical-chemical properties of each compound and meteorology from the closest Integrated Surface Database (ISD) data set obtained through NOAA's National Centers for Environmental Information (NCEI). The model was developed to be user-friendly, only requiring basic Matlab knowledge. To illustrate the effectiveness of the model, we evaluated three independent data sets of airborne PCBs simultaneously collected using passive and active samplers: at sites in Chicago, Lancaster, UK, and Toronto, Canada. The model provides Veff values comparable to those using depuration compounds and calibration against active samplers, yielding an average congener specific concentration method ratio (active/passive) of 1.1 ± 1.2. We applied the model to PUF-PAS samples collected in Chicago and show that previous methods can underestimate concentrations of PCBs by up to 40%, especially for long deployments, deployments conducted under warming conditions, and compounds with log Koa values less than 8. PMID:26963482

  13. A Model Using Local Weather Data to Determine the Effective Sampling Volume for PCB Congeners Collected on Passive Air Samplers

    PubMed Central

    2016-01-01

    We have developed and evaluated a mathematical model to determine the effective sampling volumes (Veff) of PCBs and similar compounds captured using polyurethane foam passive air samplers (PUF–PAS). We account for the variability in wind speed, air temperature, and equilibrium partitioning over the course of the deployment of the samplers. The model, provided as an annotated Matlab script, predicts the Veff as a function of physical-chemical properties of each compound and meteorology from the closest Integrated Surface Database (ISD) data set obtained through NOAA’s National Centers for Environmental Information (NCEI). The model was developed to be user-friendly, only requiring basic Matlab knowledge. To illustrate the effectiveness of the model, we evaluated three independent data sets of airborne PCBs simultaneously collected using passive and active samplers: at sites in Chicago, Lancaster, UK, and Toronto, Canada. The model provides Veff values comparable to those using depuration compounds and calibration against active samplers, yielding an average congener specific concentration method ratio (active/passive) of 1.1 ± 1.2. We applied the model to PUF–PAS samples collected in Chicago and show that previous methods can underestimate concentrations of PCBs by up to 40%, especially for long deployments, deployments conducted under warming conditions, and compounds with log Koa values less than 8. PMID:26963482

  14. Strength and weaknesses of modeling the dynamics of mode-locked lasers by means of collective coordinates

    NASA Astrophysics Data System (ADS)

    Alsaleh, M.; Mback, C. B. L.; Tchomgo Felenou, E.; Tchofo Dinda, P.; Grelu, Ph; Porsezian, K.

    2016-07-01

    We address the efficiency of theoretical tools used in the development and optimization of mode-locked fiber lasers. Our discussion is based on the practical case of modeling the dynamics of a dispersion-managed fiber laser. One conventional approach uses discrete propagation equations, followed by the analysis of the numerical results through a collective coordinate projection. We compare the latter with our dynamical collective coordinate approach (DCCA), which combines both modeling and analysis in a compact form. We show that for single pulse dynamics, the DCCA allows a much quicker solution mapping in the space of cavity parameters than the conventional approach, along with a good accuracy. We also discuss the weaknesses of the DCCA, in particular when multiple pulsing bifurcations occur.

  15. 78 FR 14838 - Proposed Information Collection Request of the Resource Justification Model (RJM); Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-07

    ...., permitting electronic submissions of responses. III. Current Actions Type of Review: Extension without change... Model (RJM); Comment Request AGENCY: Employment and Training Administration (ETA), Labor. ACTION:...

  16. Verification and adjustment of regional regression models for urban storm-runoff quality using data collected in Little Rock, Arkansas

    USGS Publications Warehouse

    Barks, C.S.

    1995-01-01

    Storm-runoff water-quality data were used to verify and, when appropriate, adjust regional regression models previously developed to estimate urban storm- runoff loads and mean concentrations in Little Rock, Arkansas. Data collected at 5 representative sites during 22 storms from June 1992 through January 1994 compose the Little Rock data base. Comparison of observed values (0) of storm-runoff loads and mean concentrations to the predicted values (Pu) from the regional regression models for nine constituents (chemical oxygen demand, suspended solids, total nitrogen, total ammonia plus organic nitrogen as nitrogen, total phosphorus, dissolved phosphorus, total recoverable copper, total recoverable lead, and total recoverable zinc) shows large prediction errors ranging from 63 to several thousand percent. Prediction errors for six of the regional regression models are less than 100 percent, and can be considered reasonable for water-quality models. Differences between 0 and Pu are due to variability in the Little Rock data base and error in the regional models. Where applicable, a model adjustment procedure (termed MAP-R-P) based upon regression with 0 against Pu was applied to improve predictive accuracy. For 11 of the 18 regional water-quality models, 0 and Pu are significantly correlated, that is much of the variation in 0 is explained by the regional models. Five of these 11 regional models consistently overestimate O; therefore, MAP-R-P can be used to provide a better estimate. For the remaining seven regional models, 0 and Pu are not significanfly correlated, thus neither the unadjusted regional models nor the MAP-R-P is appropriate. A simple estimator, such as the mean of the observed values may be used if the regression models are not appropriate. Standard error of estimate of the adjusted models ranges from 48 to 130 percent. Calibration results may be biased due to the limited data set sizes in the Little Rock data base. The relatively large values of

  17. Performance evaluation model of a pilot food waste collection system in Suzhou City, China.

    PubMed

    Wen, Zongguo; Wang, Yuanjia; De Clercq, Djavan

    2015-05-01

    This paper analyses the food waste collection and transportation (C&T) system in a pilot project in Suzhou by using a novel performance evaluation method. The method employed to conduct this analysis involves a unified performance evaluation index containing qualitative and quantitative indicators applied to data from Suzhou City. Two major inefficiencies were identified: a) low system efficiency due to insufficient processing capacity of commercial food waste facilities; and b) low waste resource utilization due to low efficiency of manual sorting. The performance evaluation indicated that the pilot project collection system's strong points included strong economics, low environmental impact and low social impact. This study also shows that Suzhou's integrated system has developed a comprehensive body of laws and clarified regulatory responsibilities for each of the various government departments to solve the problems of commercial food waste management. Based on Suzhou's experience, perspectives and lessons can be drawn for other cities and areas where food waste management systems are in the planning stage, or are encountering operational problems. PMID:25733197

  18. Collective migration of an epithelial monolayer in response to a model wound

    PubMed Central

    Poujade, M.; Grasland-Mongrain, E.; Hertzog, A.; Jouanneau, J.; Chavrier, P.; Ladoux, B.; Buguin, A.; Silberzan, P.

    2007-01-01

    Using an original microfabrication-based technique, we experimentally study situations in which a virgin surface is presented to a confluent epithelium with no damage made to the cells. Although inspired by wound-healing experiments, the situation is markedly different from classical scratch wounding because it focuses on the influence of the free surface and uncouples it from the other possible contributions such as cell damage and/or permeabilization. Dealing with Madin–Darby canine kidney cells on various surfaces, we found that a sudden release of the available surface is sufficient to trigger collective motility. This migration is independent of the proliferation of the cells that mainly takes place on the fraction of the surface initially covered. We find that this motility is characterized by a duality between collective and individual behaviors. On the one hand, the velocity fields within the monolayer are very long range and involve many cells in a coordinated way. On the other hand, we have identified very active “leader cells” that precede a small cohort and destabilize the border by a fingering instability. The sides of the fingers reveal a pluricellular actin “belt” that may be at the origin of a mechanical signaling between the leader and the followers. Experiments performed with autocrine cells constitutively expressing hepatocyte growth factor (HGF) or in the presence of exogenous HGF show a higher average velocity of the border and no leader. PMID:17905871

  19. Performance evaluation model of a pilot food waste collection system in Suzhou City, China.

    PubMed

    Wen, Zongguo; Wang, Yuanjia; De Clercq, Djavan

    2015-05-01

    This paper analyses the food waste collection and transportation (C&T) system in a pilot project in Suzhou by using a novel performance evaluation method. The method employed to conduct this analysis involves a unified performance evaluation index containing qualitative and quantitative indicators applied to data from Suzhou City. Two major inefficiencies were identified: a) low system efficiency due to insufficient processing capacity of commercial food waste facilities; and b) low waste resource utilization due to low efficiency of manual sorting. The performance evaluation indicated that the pilot project collection system's strong points included strong economics, low environmental impact and low social impact. This study also shows that Suzhou's integrated system has developed a comprehensive body of laws and clarified regulatory responsibilities for each of the various government departments to solve the problems of commercial food waste management. Based on Suzhou's experience, perspectives and lessons can be drawn for other cities and areas where food waste management systems are in the planning stage, or are encountering operational problems.

  20. An approach to collective behavior in cell cultures: modeling and analysis of ECIS data

    NASA Astrophysics Data System (ADS)

    Rabson, David; Lafalce, Evan; Lovelady, Douglas; Lo, Chun-Min

    2011-03-01

    We review recent results in which statistical measures of noise in ECIS data distinguished healthy cell cultures from cancerous or poisoned ones: after subtracting the ``signal,'' the 1 /fα noise in the healthy cultures shows longer short-time and long-time correlations. We discuss application of an artificial neural network to detect the cancer signal, and we demonstrate a computational model of cell-cell communication that produces signals similar to those of the experimental data. The simulation is based on the q -state Potts model with inspiration from the Bak-Tang-Wiesenfeld sand-pile model. We view the level of organization larger than cells but smaller than organs or tissues as a kind of ``mesoscopic'' biological physics, in which few-body interactions dominate, and the experiments and computational model as ways of exploring this regime.

  1. Collective learning modeling based on the kinetic theory of active particles

    NASA Astrophysics Data System (ADS)

    Burini, D.; De Lillo, S.; Gibelli, L.

    2016-03-01

    This paper proposes a systems approach to the theory of perception and learning in populations composed of many living entities. Starting from a phenomenological description of these processes, a mathematical structure is derived which is deemed to incorporate their complexity features. The modeling is based on a generalization of kinetic theory methods where interactions are described by theoretical tools of game theory. As an application, the proposed approach is used to model the learning processes that take place in a classroom.

  2. Collective learning modeling based on the kinetic theory of active particles.

    PubMed

    Burini, D; De Lillo, S; Gibelli, L

    2016-03-01

    This paper proposes a systems approach to the theory of perception and learning in populations composed of many living entities. Starting from a phenomenological description of these processes, a mathematical structure is derived which is deemed to incorporate their complexity features. The modeling is based on a generalization of kinetic theory methods where interactions are described by theoretical tools of game theory. As an application, the proposed approach is used to model the learning processes that take place in a classroom.

  3. Modeling municipal solid waste collection: A generalized vehicle routing model with multiple transfer stations, gather sites and inhomogeneous vehicles in time windows.

    PubMed

    Son, Le Hoang; Louati, Amal

    2016-06-01

    Municipal Solid Waste (MSW) collection is a necessary process in any municipality resulting in the quality-of-life, economic aspects and urban structuralization. The intrinsic nature of MSW collection relates to the development of effective vehicle routing models that optimize the total traveling distances of vehicles, the environmental emission and the investment costs. In this article, we propose a generalized vehicle routing model including multiple transfer stations, gather sites and inhomogeneous vehicles in time windows for MSW collection. It takes into account traveling in one-way routes, the number of vehicles per m(2) and waiting time at traffic stops for reduction of operational time. The proposed model could be used for scenarios having similar node structures and vehicles' characteristics. A case study at Danang city, Vietnam is given to illustrate the applicability of this model. The experimental results have clearly shown that the new model reduces both total traveling distances and operational hours of vehicles in comparison with those of practical scenarios. Optimal routes of vehicles on streets and markets at Danang are given. Those results are significant to practitioners and local policy makers.

  4. Modeling municipal solid waste collection: A generalized vehicle routing model with multiple transfer stations, gather sites and inhomogeneous vehicles in time windows.

    PubMed

    Son, Le Hoang; Louati, Amal

    2016-06-01

    Municipal Solid Waste (MSW) collection is a necessary process in any municipality resulting in the quality-of-life, economic aspects and urban structuralization. The intrinsic nature of MSW collection relates to the development of effective vehicle routing models that optimize the total traveling distances of vehicles, the environmental emission and the investment costs. In this article, we propose a generalized vehicle routing model including multiple transfer stations, gather sites and inhomogeneous vehicles in time windows for MSW collection. It takes into account traveling in one-way routes, the number of vehicles per m(2) and waiting time at traffic stops for reduction of operational time. The proposed model could be used for scenarios having similar node structures and vehicles' characteristics. A case study at Danang city, Vietnam is given to illustrate the applicability of this model. The experimental results have clearly shown that the new model reduces both total traveling distances and operational hours of vehicles in comparison with those of practical scenarios. Optimal routes of vehicles on streets and markets at Danang are given. Those results are significant to practitioners and local policy makers. PMID:27036996

  5. A hemodynamics model to study the collective behavior of the ventricular-arterial system

    NASA Astrophysics Data System (ADS)

    Lin Wang, Yuh-Ying; Wang, Wei-Kung

    2013-01-01

    Applying principles from complex systems to study the efficacy of integrative therapies has become a new interest in medical research. We aimed to construct a concise model for the ventricular-arterial (VA) system and to provide a systematic method for exploring its overall behavior. The transportation of blood from the heart to the peripheral arterioles via hydraulic pressure forces was described by a multi-rank model. Parts of the VA system that have strong mutual interactions were combined into a single sub system. Sub systems of four different ranks were characterized. We then applied the multi-rank model to analyze the aortic pressure wave generated by the periodic ventricular blood ejection, the renal pressure in response to the input from the VA system, and the blood flowing from the renal artery to its arterioles. Maintaining the pressure distribution along the main arteries and in all of the organs with the lowest possible ventricular input turned out to be the first principle for the operation of an efficient VA system. By this principle, we pointed out the benefit of some arterial structures in mammals, derived specific regulation rules and deduced some fundamental concepts for healing. The justification of the biomechanics in our model that differed greatly from those in the prevailing models was given. We concluded that the oscillatory motion and the pressure pulse of the arterial system can be analyzed as steady states with resonance behaviors and suggested utilizing this model to construct integrative therapies for diseases correlated with abnormality in blood circulation.

  6. Assessment of an Underwater Light Attenuation Model Using Bio-optical Data Collected in Monterey Bay, CA.

    NASA Astrophysics Data System (ADS)

    Penta, B.; Goode, W.; Blum, M.; Lamb, E.; Shulman, I.; Jolliff, J.; Anderson, S.; Derada, S.

    2008-12-01

    A new model for the underwater propagation of photosynthetically available radiation (PAR) based on inherent optical properties (IOP) has been developed for use in marine ecosystem models. This "pseudo- spectral," IOP-based model has improved accuracy compared to standard Lambert-Beer law schemes while being appreciably more computationally efficient than multi-spectral optical models. IOP input to the model can originate from an ecosystem model, remote sensing observations, in-situ data, or any combination thereof. To assess the utility of this new light model, we employ a bio-optical data set collected in Monterey Bay, California during May and June 2008 as part of the Naval Research Laboratory's Bio-Optical Studies of Predictability and Assimilation for the Coastal Environment (BIOSPACE) program. A diverse set of sampling platforms included satellites, gliders, autonomous underwater vehicles, profiling moorings (SEPTR), a ship- towed platform (ScanFish MK II), and ship-based profiling and water sampling. Predictions derived from an ecosystem model using different parameterizations of the IOP-based light scheme are compared.

  7. Nuclear Collective Rotation in the SU_{3} Model. I --Semiclassical Rotation--

    NASA Astrophysics Data System (ADS)

    Kinouchi, S.; Kammuri, T.; Kishimoto, T.

    1989-01-01

    The collective rotation of a nuclear system having the quadrupole-quadrupole interaction is described by the dynamical nuclear field theory (DNFT). We use the one-body harmonic oscillator potential and restrict the discussion to the Delta N = 0 transitions. Energy eigenvalues of the resulting SU_{3} Hamiltonian are obtained by using the eigenstates of the cranked harmonic oscillator. Both the low and high spin states are studied by the perturbative DNFT, reproducing successfully the diagonalization results. In spite of the simple rotational spectrum, the nuclear shape is seriously influenced by the rotational disturbances. Similarities with our previous analyses of the pair rotation are pointed out. Especially, the SU_{3} rotation in the odd mass system decouples with the particle motion just as the pair rotation does in the single-j limit.

  8. Double Stimulation in the Waiting Experiment with Collectives: Testing a Vygotskian Model of the Emergence of Volitional Action.

    PubMed

    Sannino, Annalisa

    2016-03-01

    This study explores what human conduct looks like when research embraces uncertainty and distance itself from the dominant methodological demands of control and predictability. The context is the waiting experiment originally designed in Kurt Lewin's research group, discussed by Vygotsky as an instance among a range of experiments related to his notion of double stimulation. Little attention has been paid to this experiment, despite its great heuristic potential for charting the terrain of uncertainty and agency in experimental settings. Behind the notion of double stimulation lays Vygotsky's distinctive view of human beings' ability to intentionally shape their actions. Accordingly, human beings in situations of uncertainty and cognitive incongruity can rely on artifacts which serve the function of auxiliary motives and which help them undertake volitional actions. A double stimulation model depicting how such actions emerge is tested in a waiting experiment conducted with collectives, in contrast with a previous waiting experiment conducted with individuals. The model, validated in the waiting experiment with individual participants, applies only to a limited extent to the collectives. The analysis shows the extent to which double stimulation takes place in the waiting experiment with collectives, the differences between the two experiments, and what implications can be drawn for an expanded view on experiments.

  9. Double Stimulation in the Waiting Experiment with Collectives: Testing a Vygotskian Model of the Emergence of Volitional Action.

    PubMed

    Sannino, Annalisa

    2016-03-01

    This study explores what human conduct looks like when research embraces uncertainty and distance itself from the dominant methodological demands of control and predictability. The context is the waiting experiment originally designed in Kurt Lewin's research group, discussed by Vygotsky as an instance among a range of experiments related to his notion of double stimulation. Little attention has been paid to this experiment, despite its great heuristic potential for charting the terrain of uncertainty and agency in experimental settings. Behind the notion of double stimulation lays Vygotsky's distinctive view of human beings' ability to intentionally shape their actions. Accordingly, human beings in situations of uncertainty and cognitive incongruity can rely on artifacts which serve the function of auxiliary motives and which help them undertake volitional actions. A double stimulation model depicting how such actions emerge is tested in a waiting experiment conducted with collectives, in contrast with a previous waiting experiment conducted with individuals. The model, validated in the waiting experiment with individual participants, applies only to a limited extent to the collectives. The analysis shows the extent to which double stimulation takes place in the waiting experiment with collectives, the differences between the two experiments, and what implications can be drawn for an expanded view on experiments. PMID:26318436

  10. Micro-Tom Tomato as an Alternative Plant Model System: Mutant Collection and Efficient Transformation.

    PubMed

    Shikata, Masahito; Ezura, Hiroshi

    2016-01-01

    Tomato is a model plant for fruit development, a unique feature that classical model plants such as Arabidopsis and rice do not have. The tomato genome was sequenced in 2012 and tomato is becoming very popular as an alternative system for plant research. Among many varieties of tomato, Micro-Tom has been recognized as a model cultivar for tomato research because it shares some key advantages with Arabidopsis including its small size, short life cycle, and capacity to grow under fluorescent lights at a high density. Mutants and transgenic plants are essential materials for functional genomics research, and therefore, the availability of mutant resources and methods for genetic transformation are key tools to facilitate tomato research. Here, we introduce the Micro-Tom mutant database "TOMATOMA" and an efficient transformation protocol for Micro-Tom.

  11. Harmonic oscillator potential with a quartic anharmonicity in the prolate γ-rigid collective geometrical model

    NASA Astrophysics Data System (ADS)

    Budaca, Radu

    2015-12-01

    An analytical expression for the energy spectrum of the ground and β bands was obtained in the axially symmetric γ-rigid regime of the Bohr-Mottelson Hamiltonian with a general quartic anharmonic oscillator potential in the β shape variable. As the Schrodinger equation for such a potential is not exactly solvable, the energy formula is derived on the basis of the JWKB approximation. Due to the scaling property of the quartic oscillator problem, the resulting energy depends on a single parameter up to an overall multiplicative constant. The upper limit of the domain of values for the free parameter is established by comparing the ground state eigenvalues with the corresponding numerically calculated results. Studying the behavior of the potential and of the whole energy spectrum as function of the free parameter, one establishes the present model's place between other γ-rigid models. The agreement with experiment is achieved through model fits for few near-vibrational nuclei.

  12. Collective excitations and sum rules for the Hubbard model in the spin-density-wave regime

    NASA Astrophysics Data System (ADS)

    Monien, H.; Bedell, K. S.

    1992-02-01

    A variational estimate for the spin-wave velocity of the one-band Hubbard model on a square lattice in the spin-density-wave regime is studied. The estimate is given by the ratio of the f-sum rule to the static structure factor of the transverse-spin response function. The known results for the Heisenberg model are used to obtain results for those quantities in the large-U limit of the Hubbard model. The f-sum rule and static structure factor are calculated using the random-phase approximation (RPA). The spin-wave velocity calculated in the RPA, in the spin-density wave ground state, violates the variational bound.

  13. Promoting a Collective Conscience: Designing a Resilient Staff-Student Partnership Model for Educational Development

    ERIC Educational Resources Information Center

    Little, Sabine

    2016-01-01

    This paper discusses experiences of a student-ambassador network within one UK-based Centre for Excellence in Teaching and Learning, problematising key issues in relation to transience in staff-student partnerships in high education, and highlighting the importance of the educational developer in facilitating institution-wide partnership models.…

  14. Spatio-Temporal Dynamics in Collective Frog Choruses Examined by Mathematical Modeling and Field Observations

    NASA Astrophysics Data System (ADS)

    Aihara, Ikkyu; Mizumoto, Takeshi; Otsuka, Takuma; Awano, Hiromitsu; Nagira, Kohei; Okuno, Hiroshi G.; Aihara, Kazuyuki

    2014-01-01

    This paper reports theoretical and experimental studies on spatio-temporal dynamics in the choruses of male Japanese tree frogs. First, we theoretically model their calling times and positions as a system of coupled mobile oscillators. Numerical simulation of the model as well as calculation of the order parameters show that the spatio-temporal dynamics exhibits bistability between two-cluster antisynchronization and wavy antisynchronization, by assuming that the frogs are attracted to the edge of a simple circular breeding site. Second, we change the shape of the breeding site from the circle to rectangles including a straight line, and evaluate the stability of two-cluster and wavy antisynchronization. Numerical simulation shows that two-cluster antisynchronization is more frequently observed than wavy antisynchronization. Finally, we recorded frog choruses at an actual paddy field using our sound-imaging method. Analysis of the video demonstrated a consistent result with the aforementioned simulation: namely, two-cluster antisynchronization was more frequently realized.

  15. Data collection handbook to support modeling the impacts of radioactive material in soil

    SciTech Connect

    Yu, C.; Cheng, J.J.; Jones, L.G.; Wang, Y.Y.; Faillace, E.; Loureiro, C.; Chia, Y.P.

    1993-04-01

    A pathway analysis computer code called RESRAD has been developed for implementing US Department of Energy Residual Radioactive Material Guidelines. Hydrogeological, meteorological, geochemical, geometrical (size, area, depth), and material-related (soil, concrete) parameters are used in the RESRAD code. This handbook discusses parameter definitions, typical ranges, variations, measurement methodologies, and input screen locations. Although this handbook was developed primarily to support the application of RESRAD, the discussions and values are valid for other model applications.

  16. Developing a model for understanding patient collection of observations of daily living: A qualitative meta-synthesis of the Project HealthDesign Program

    PubMed Central

    Cohen, Deborah J.; Keller, Sara R.; Hayes, Gillian R.; Dorr, David A.; Ash, Joan S.; Sittig, Dean F.

    2016-01-01

    We conducted a meta-synthesis of five different studies that developed, tested, and implemented new technologies for the purpose of collecting Observations of Daily Living (ODL). From this synthesis, we developed a model to explain user motivation as it relates to ODL collection. We describe this model that includes six factors that motivate patients’ collection of ODL data: usability, illness experience, relevance of ODLs, information technology infrastructure, degree of burden, and emotional activation. We show how these factors can act as barriers or facilitators to the collection of ODL data and how interacting with care professionals and sharing ODL data may also influence ODL collection, health-related awareness, and behavior change. The model we developed and used to explain ODL collection can be helpful to researchers and designers who study and develop new, personal health technologies to empower people to improve their health. PMID:26949381

  17. The impact of Local Authorities' interventions on household waste collection: a case study approach using time series modelling.

    PubMed

    Cole, Christine; Quddus, Mohammed; Wheatley, Andrew; Osmani, Mohamed; Kay, Kath

    2014-02-01

    At a local Government level there have been many interventions and changes made to household waste collection services to meet new regulatory requirements. These changes include separate collection of recyclable and organic materials. This paper has used a time series model to quantify the success of interventions introduced by a LA. The case study was a medium sized UK LA, Charnwood Borough Council (CBC), the research analyses monthly data of quantities of recyclates, garden waste for composting and residual waste for landfill disposal. The time series model was validated with a five year data set and used to measure the impacts of the various changes to identify which intervention was the most successful, while controlling for season and number of working days. The results show the interventions analysed both had abrupt and permanent positive impacts on the yield of recyclable materials, and a corresponding negative impact on the residual waste. The model could be added to the National data base to help LAs to compare interventions and to understand which schemes encourage householder participation and improve recycling performance. PMID:24256716

  18. The impact of Local Authorities' interventions on household waste collection: a case study approach using time series modelling.

    PubMed

    Cole, Christine; Quddus, Mohammed; Wheatley, Andrew; Osmani, Mohamed; Kay, Kath

    2014-02-01

    At a local Government level there have been many interventions and changes made to household waste collection services to meet new regulatory requirements. These changes include separate collection of recyclable and organic materials. This paper has used a time series model to quantify the success of interventions introduced by a LA. The case study was a medium sized UK LA, Charnwood Borough Council (CBC), the research analyses monthly data of quantities of recyclates, garden waste for composting and residual waste for landfill disposal. The time series model was validated with a five year data set and used to measure the impacts of the various changes to identify which intervention was the most successful, while controlling for season and number of working days. The results show the interventions analysed both had abrupt and permanent positive impacts on the yield of recyclable materials, and a corresponding negative impact on the residual waste. The model could be added to the National data base to help LAs to compare interventions and to understand which schemes encourage householder participation and improve recycling performance.

  19. Prospects of Genomic Prediction in the USDA Soybean Germplasm Collection: Historical Data Creates Robust Models for Enhancing Selection of Accessions

    PubMed Central

    Jarquin, Diego; Specht, James; Lorenz, Aaron

    2016-01-01

    The identification and mobilization of useful genetic variation from germplasm banks for use in breeding programs is critical for future genetic gain and protection against crop pests. Plummeting costs of next-generation sequencing and genotyping is revolutionizing the way in which researchers and breeders interface with plant germplasm collections. An example of this is the high density genotyping of the entire USDA Soybean Germplasm Collection. We assessed the usefulness of 50K single nucleotide polymorphism data collected on 18,480 domesticated soybean (Glycine max) accessions and vast historical phenotypic data for developing genomic prediction models for protein, oil, and yield. Resulting genomic prediction models explained an appreciable amount of the variation in accession performance in independent validation trials, with correlations between predicted and observed reaching up to 0.92 for oil and protein and 0.79 for yield. The optimization of training set design was explored using a series of cross-validation schemes. It was found that the target population and environment need to be well represented in the training set. Second, genomic prediction training sets appear to be robust to the presence of data from diverse geographical locations and genetic clusters. This finding, however, depends on the influence of shattering and lodging, and may be specific to soybean with its presence of maturity groups. The distribution of 7608 nonphenotyped accessions was examined through the application of genomic prediction models. The distribution of predictions of phenotyped accessions was representative of the distribution of predictions for nonphenotyped accessions, with no nonphenotyped accessions being predicted to fall far outside the range of predictions of phenotyped accessions. PMID:27247288

  20. Effect of Pap Smear Collection and Carrageenan on Cervicovaginal Human Papillomavirus-16 Infection in a Rhesus Macaque Model

    PubMed Central

    Roberts, Jeffrey N.; Kines, Rhonda C.; Katki, Hormuzd A.; Lowy, Douglas R.

    2011-01-01

    Background Human papillomavirus (HPV) infection of the genital mucosa is thought to require trauma to the cervicovaginal epithelium. Therefore, we determined whether a cytology specimen collection procedure (Pap smear), which disrupts the epithelium by design, renders the cervix more susceptible to HPV infection in a primate model. Methods In a series of female rhesus macaques, a speculum examination was performed with (n = 8) or without (n = 4) a cytology specimen collection procedure as it is commonly practiced in a gynecology clinic. An internal digital examination was performed after specimen collection using Surgilube (n = 4) or 1% iota-carrageenan, a previously indentified HPV inhibitor (n = 4) as the lubricant. The cervix was then inoculated with HPV16 pseudovirions expressing red fluorescent protein. After 3 days, the reproductive tracts were excised and the cervix was cryosectioned. Sections were analyzed by fluorescent confocal microscopy for the number of red fluorescent protein–positive keratinocytes. Results Substantial infection of the ectocervix, the transformation zone, and the endocervix was detected, but only in conjunction with the cytology specimen collection procedure (cytology using Surgilube vs without cytology using Surgilube, mean = 84 infectious events per section vs mean = 0.05 infectious events per section, difference = 84 infectious events per section, 95% confidence interval = 19 to 384 infectious events per section). When the carrageenan gel was substituted for Surgilube for an internal digital examination, the mean number of infectious events decreased (carrageenan gel vs Surgilube, mean = 3.5 events per section vs mean = 84 infectious events per section difference = 81 events per section, 95% confidence interval = 33 to 213 events per section). Conclusions These findings indicate that cytology screening in women might lead to a transient enhancement of susceptibility to HPV infection and that use of a carrageenan-based gel during

  1. {Sigma}PAH: A model to predict the toxicity of polynuclear aromatic hydrocarbon mixtures in field-collected sediments

    SciTech Connect

    Swartz, R.C.; Schults, D.W.; Ozretich, R.J.; Lamberson, J.O.; Cole, F.A.; Ferraro, S.P.; DeWitt, T.H.; Redmond, M.S.

    1995-11-01

    The {Sigma}PAH model estimates the probability of toxicity of PAH-contaminated sediments using a combination of equilibrium partitioning, WSAR, toxic unit, additivity, and concentration-response models. The sediment concentration of organic carbon and 13 PAH (polynuclear aromatic hydrocarbon) compounds were measured. Interstitial water concentrations (PAH{sub iw}) of the 13 compounds were predicted by equilibrium partitioning. The 10-d LC50 of each compound in interstitial water (10-d LC50{sub iw}) was predicted by a QSAR regression of 10-d LC50{sub iw} (From spiked sediment tests) to K{sub ow}. Toxic unit concentrations of individual compounds (TU{sub i}) were predicted as PAH{sub iw}/10-d LC50{sub iw}. The total number of toxic units of the 13 compounds ({Sigma}TU{sub i}) was calculated assuming the additivity of toxic effects of PAHs. {Sigma}TU{sub i} was used to predict the probability of toxicity to marine and estuarine amphipods using a concentration-response model derived from spiked sediment toxicity tests. The {Sigma}PAH model was verified by comparing predicted and observed toxicity in field-collected sediment samples. There was 86.6% correspondence and no significant difference between predicted and observed toxicity at PAH-contaminated sites. Ecological-effect levels predicted by the {Sigma}PAH model correspond with several sediment-quality guidelines.

  2. Extracting Kinetic and Stationary Distribution Information from Short MD Trajectories via a Collection of Surrogate Diffusion Models

    PubMed Central

    Calderon, Christopher P.; Arora, Karunesh

    2009-01-01

    Low-dimensional stochastic models can summarize dynamical information and make long time predictions associated with observables of complex atomistic systems. Maximum likelihood based techniques for estimating low-dimensional surrogate diffusion models from relatively short time series are presented. It is found that a heterogeneous population of slowly evolving conformational degrees of freedom modulates the dynamics. This underlying heterogeneity results in a collection of estimated low-dimensional diffusion models. Numerical techniques for exploiting this finding to approximate skewed histograms associated with the simulation are presented. In addition, statistical tests are also used to assess the validity of the models and determine physically relevant sampling information, e.g. the maximum sampling frequency at which one can discretely sample from an atomistic time series and have a surrogate diffusion model pass goodness-of-fit tests. The information extracted from such analyses can possibly be used to assist umbrella sampling computations as well as help in approximating effective diffusion coefficients. The techniques are demonstrated on simulations of Adenylate Kinase. PMID:20046947

  3. Collective Cell Motion in an Epithelial Sheet Can Be Quantitatively Described by a Stochastic Interacting Particle Model

    PubMed Central

    Cochet, Olivier; Grasland-Mongrain, Erwan; Silberzan, Pascal; Hakim, Vincent

    2013-01-01

    Modelling the displacement of thousands of cells that move in a collective way is required for the simulation and the theoretical analysis of various biological processes. Here, we tackle this question in the controlled setting where the motion of Madin-Darby Canine Kidney (MDCK) cells in a confluent epithelium is triggered by the unmasking of free surface. We develop a simple model in which cells are described as point particles with a dynamic based on the two premises that, first, cells move in a stochastic manner and, second, tend to adapt their motion to that of their neighbors. Detailed comparison to experimental data show that the model provides a quantitatively accurate description of cell motion in the epithelium bulk at early times. In addition, inclusion of model “leader” cells with modified characteristics, accounts for the digitated shape of the interface which develops over the subsequent hours, providing that leader cells invade free surface more easily than other cells and coordinate their motion with their followers. The previously-described progression of the epithelium border is reproduced by the model and quantitatively explained. PMID:23505356

  4. Use of laser 3D surface digitizer in data collection and 3D modeling of anatomical structures

    NASA Astrophysics Data System (ADS)

    Tse, Kelly; Van Der Wall, Hans; Vu, Dzung H.

    2006-02-01

    A laser digitizer (Konica-Minolta Vivid 910) is used to obtain 3-dimensional surface scans of anatomical structures with a maximum resolution of 0.1mm. Placing the specimen on a turntable allows multiple scans allaround because the scanner only captures data from the portion facing its lens. A computer model is generated using 3D modeling software such as Geomagic. The 3D model can be manipulated on screen for repeated analysis of anatomical features, a useful capability when the specimens are rare or inaccessible (museum collection, fossils, imprints in rock formation.). As accurate measurements can be performed on the computer model, instead of taking measurements on actual specimens only at the archeological excavation site e.g., a variety of quantitative data can be later obtained on the computer model in the laboratory as new ideas come to mind. Our group had used a mechanical contact digitizer (Microscribe) for this purpose, but with the surface digitizer, we have been obtaining data sets more accurately and more quickly.

  5. Transaction-neutral implanted data collection interface as EMR driver: a model for emerging distributed medical technologies.

    PubMed

    Lorence, Daniel; Sivaramakrishnan, Anusha; Richards, Michael

    2010-08-01

    Electronic Medical Record (EMR) and Electronic Health Record (EHR) adoption continues to lag across the US. Cost, inconsistent formats, and concerns about control of patient information are among the most common reasons for non-adoption in physician practice settings. The emergence of wearable and implanted mobile technologies, employed in distributed environments, promises a fundamentally different information infrastructure, which could serve to minimize existing adoption resistance. Proposed here is one technology model for overcoming adoption inconsistency and high organization-specific implementation costs, using seamless, patient controlled data collection. While the conceptual applications employed in this technology set are provided by way of illustration, they may also serve as a transformative model for emerging EMR/EHR requirements. PMID:20703915

  6. Evaluating the efficiency of municipalities in collecting and processing municipal solid waste: a shared input DEA-model.

    PubMed

    Rogge, Nicky; De Jaeger, Simon

    2012-10-01

    This paper proposed an adjusted "shared-input" version of the popular efficiency measurement technique Data Envelopment Analysis (DEA) that enables evaluating municipality waste collection and processing performances in settings in which one input (waste costs) is shared among treatment efforts of multiple municipal solid waste fractions. The main advantage of this version of DEA is that it not only provides an estimate of the municipalities overall cost efficiency but also estimates of the municipalities' cost efficiency in the treatment of the different fractions of municipal solid waste (MSW). To illustrate the practical usefulness of the shared input DEA-model, we apply the model to data on 293 municipalities in Flanders, Belgium, for the year 2008.

  7. Collective molecular dissipation on Navier-Stokes macroscopic scales: Accretion disc viscous modeling in SPH

    NASA Astrophysics Data System (ADS)

    Lanzafame, Giuseppe

    2015-02-01

    In the nonlinear Navier-Stokes viscous flow dynamics, physical damping is mathematically accomplished by a braking term in the momentum equation, corresponding to a heating term in the energy equation, both responsible of the conversion of mechanical energy into heat. In such two terms, it is essential the role of the viscous stress tensor, relative to contiguous macroscopic moving flow components, depending on the macroscopic viscosity coefficient ν. A working formulation for ν can always be found analytically, tuning some arbitrary parameters in the current known formulations, according to the geometry, morphology and physics of the flow. Instead, in this paper, we write an alternative hybrid formulation for ν, where molecular parameters are also included. Our expression for ν has a more physical interpretation of the internal damping in dilute gases because the macroscopic viscosity is related to the small scale molecular dissipation, not strictly dependent on the flow morphology, as well as it is free of any arbitrary parameter. Results for some basic 2D tests are shown in the smoothed particle hydrodynamics (SPH) framework. An application to the 3D accretion disc modeling for low mass cataclysmic variables is also discussed. Consequences of the macroscopic viscosity coefficient reformulation in a more strictly physical terms on the thermal conductivity coefficient for dilute gases are also discussed.

  8. Using field data to test locust migratory band collective movement models

    PubMed Central

    Buhl, J.; Sword, Gregory A.; Simpson, Stephen J.

    2012-01-01

    Wingless locust nymphs can form massive migratory groups known as bands, whose coordinated movement results from local interactions. We analysed the spatial distribution of locusts within naturally occurring bands and compared them with computer simulations to infer which interaction rules are used by individuals. We found that the empirical radial distribution of neighbours around a focal individual was isotropic, indicating a tendency for locusts to interact with neighbours all around them, rather than a bias towards pursuing individuals ahead or escaping from the ones following behind. By using maps of neighbour densities and pair correlation functions, we found evidence for a short-range repulsion force, balanced by a clustering force, presumably alignment and/or attraction, at a distance of around 3 cm. These results were similar to those observed when using a ‘zonal’ self-propelled particles model where repulsion/alignment/attraction forces are delimited by concentric circular zones of set radii. However, the profiles obtained either by using different combinations of forces, limiting the number of neighbours involved in interactions, or by varying the range of some zones, all appeared to produce similar results, thereby limiting the ability to more precisely determine the rules underlying locust interactions. PMID:24312729

  9. An expanded collection and refined consensus model of glmS ribozymes

    PubMed Central

    McCown, Phillip J.; Roth, Adam; Breaker, Ronald R.

    2011-01-01

    Self-cleaving glmS ribozymes selectively bind glucosamine-6-phosphate (GlcN6P) and use this metabolite as a cofactor to promote self-cleavage by internal phosphoester transfer. Representatives of the glmS ribozyme class are found in Gram-positive bacteria where they reside in the 5′ untranslated regions (UTRs) of glmS messenger RNAs that code for the essential enzyme L-glutamine:D-fructose-6-phosphate aminotransferase. By using comparative sequence analyses, we have expanded the number of glmS ribozyme representatives from 160 to 463. All but two glmS ribozymes are present in glmS mRNAs and most exhibit striking uniformity in sequence and structure, which are features that make representatives attractive targets for antibacterial drug development. However, our discovery of rare variants broadens the consensus sequence and structure model. For example, in the Deinococcus-Thermus phylum, several structural variants exist that carry additional stems within the catalytic core and changes to the architecture of core-supporting substructures. These findings reveal that glmS ribozymes have a broader phylogenetic distribution than previously known and suggest that additional rare structural variants may remain to be discovered. PMID:21367971

  10. Simulation modelling analysis for small sets of single-subject data collected over time.

    PubMed

    Borckardt, Jeffrey J; Nash, Michael R

    2014-01-01

    The behavioural data yielded by single subjects in naturalistic and controlled settings likely contain valuable information to scientists and practitioners alike. Although some of the properties unique to this data complicate statistical analysis, progress has been made in developing specialised techniques for rigorous data evaluation. There are no perfect tests currently available to analyse short autocorrelated data streams, but there are some promising approaches that warrant further development. Although many approaches have been proposed, and some appear better than others, they all have some limitations. When data sets are large enough (∼30 data points per phase), the researcher has a reasonably rich pallet of statistical tools from which to choose. However, when the data set is sparse, the analytical options dwindle. Simulation modelling analysis (SMA; described in this article) is a relatively new technique that appears to offer acceptable Type-I and Type-II error rate control with short streams of autocorrelated data. However, at this point, it is probably too early to endorse any specific statistical approaches for short, autocorrelated time-series data streams. While SMA shows promise, more work is needed to verify that it is capable of reliable Type-I and Type-II error performance with short serially dependent streams of data. PMID:24641472

  11. Does Model Development Ahead of Data Collection Have Merit? A Case for Advancing Non-Local Fluvial Transport Theories

    NASA Astrophysics Data System (ADS)

    Voller, V. R.; Falcini, F.; Foufoula-Georgiou, E.; Ganti, V.; Paola, C.; Hill, K. M.; Swenson, J. B.; Longjas, A.

    2013-12-01

    The purpose of this work is to suggest how experiments might be constructed to provide data to test recently proposed phenomenological non-local model of depositional transport; formulated on the basis of morphological arguments but with limited data. A sound methodology for developing models of geological systems is to first collect significant data and then carefully identify an appropriate model form and parameters. An alternative approach is to construct what might be referred to as a phenomenological model, where limited observation of the system is used to suggest an appropriate mathematical form that matches the critical nature of the physical system behavior. By their nature, phenomenological models are often developed within a fairly narrow range of observations. In this way, interesting findings can occur when the models are modified and exercised across wider physical domains, in particular in domains where there is an absence of hard data to corroborate or invalidate the model predictions. Although this approach might be frown on my some, it is important to recognize the stellar and proven track record of phenomenological models, which despite the original scarcity of data, often pave the way to new perspectives and important findings. The poster child example is the Higgs boson. In the early 60's manipulation of the quantum field equations revealed a critical inconsistency related to the masses of fundamental particles that could only be mathematically resolved by assuming that they operated within a field that would exert drag; this conjecture took almost fifty years and the vast experimental operation of the Large Hadron Collider to physically confirm. In this work we examine a current phenomenological model used to describe non-local transport in fluvial sediment domains. This model has its genesis in attempting to describe the shapes of hill slope profiles, while acknowledging the fact that two points of the landscape with the same local slope are

  12. Collective Commitment and Collective Efficacy: A Theoretical Model for Understanding the Motivational Dynamics of Dilemma Resolution in Inter-Professional Work

    ERIC Educational Resources Information Center

    Rose, Jo; Norwich, Brahm

    2014-01-01

    This paper presents a new theoretical model which conceptualizes inter-professional and multi-agency collaborative working, at the level of the individual within a group. This arises from a review of the literature around joint working, and is based on social psychological theories which refer to shared goals. The model assumes that collective…

  13. Stochastic simulation tools and continuum models for describing two-dimensional collective cell spreading with universal growth functions

    NASA Astrophysics Data System (ADS)

    Jin, Wang; Penington, Catherine J.; McCue, Scott W.; Simpson, Matthew J.

    2016-10-01

    Two-dimensional collective cell migration assays are used to study cancer and tissue repair. These assays involve combined cell migration and cell proliferation processes, both of which are modulated by cell-to-cell crowding. Previous discrete models of collective cell migration assays involve a nearest-neighbour proliferation mechanism where crowding effects are incorporated by aborting potential proliferation events if the randomly chosen target site is occupied. There are two limitations of this traditional approach: (i) it seems unreasonable to abort a potential proliferation event based on the occupancy of a single, randomly chosen target site; and, (ii) the continuum limit description of this mechanism leads to the standard logistic growth function, but some experimental evidence suggests that cells do not always proliferate logistically. Motivated by these observations, we introduce a generalised proliferation mechanism which allows non-nearest neighbour proliferation events to take place over a template of r≥slant 1 concentric rings of lattice sites. Further, the decision to abort potential proliferation events is made using a crowding function, f(C), which accounts for the density of agents within a group of sites rather than dealing with the occupancy of a single randomly chosen site. Analysing the continuum limit description of the stochastic model shows that the standard logistic source term, λ C(1-C), where λ is the proliferation rate, is generalised to a universal growth function, λ C f(C). Comparing the solution of the continuum description with averaged simulation data indicates that the continuum model performs well for many choices of f(C) and r. For nonlinear f(C), the quality of the continuum-discrete match increases with r.

  14. Collective modes and Kosterlitz-Thouless transition in a magnetic field in the planar Nambu–Jona-Lasinio model

    DOE PAGESBeta

    Cao, Gaoqing; He, Lianyi; Zhuang, Pengfei

    2014-09-15

    It is known that a constant magnetic field is a strong catalyst of dynamical chiral symmetry breaking in 2+1 dimensions, leading to generating dynamical fermion mass even at weakest attraction. In this work we investigate the collective modes associated with the dynamical chiral symmetry breaking in a constant magnetic field in the (2+1)-dimensional Nambu–Jona-Lasinio model with continuous U(1) chiral symmetry. We introduce a self-consistent scheme to evaluate the propagators of the collective modes at the leading order in 1/N. The contributions from the vacuum and from the magnetic field are separated such that we can employ the well-established regularization schememore » for the case of vanishing magnetic field. The same scheme can be applied to the study of the next-to-leading order correction in 1/N. We show that the sigma mode is always a lightly bound state with its mass being twice the dynamical fermion mass for arbitrary strength of the magnetic field. Since the dynamics of the collective modes is always 2+1 dimensional, the finite temperature transition should be of the Kosterlitz-Thouless (KT) type. We determine the KT transition temperature TKT as well as the mass melting temperature T* as a function of the magnetic field. It is found that the pseudogap domain TKT < T < T* is enlarged with increasing strength of the magnetic field. The influence of a chiral imbalance or axial chemical potential μ5 is also studied. We find that even a constant axial chemical potential μ5 can lead to inverse magnetic catalysis of the KT transition temperature in 2+1 dimensions. As a result, the inverse magnetic catalysis behavior is actually the de Haas–van Alphen oscillation induced by the interplay between the magnetic field and the Fermi surface.« less

  15. Collective modes and Kosterlitz-Thouless transition in a magnetic field in the planar Nambu–Jona-Lasinio model

    SciTech Connect

    Cao, Gaoqing; He, Lianyi; Zhuang, Pengfei

    2014-09-15

    It is known that a constant magnetic field is a strong catalyst of dynamical chiral symmetry breaking in 2+1 dimensions, leading to generating dynamical fermion mass even at weakest attraction. In this work we investigate the collective modes associated with the dynamical chiral symmetry breaking in a constant magnetic field in the (2+1)-dimensional Nambu–Jona-Lasinio model with continuous U(1) chiral symmetry. We introduce a self-consistent scheme to evaluate the propagators of the collective modes at the leading order in 1/N. The contributions from the vacuum and from the magnetic field are separated such that we can employ the well-established regularization scheme for the case of vanishing magnetic field. The same scheme can be applied to the study of the next-to-leading order correction in 1/N. We show that the sigma mode is always a lightly bound state with its mass being twice the dynamical fermion mass for arbitrary strength of the magnetic field. Since the dynamics of the collective modes is always 2+1 dimensional, the finite temperature transition should be of the Kosterlitz-Thouless (KT) type. We determine the KT transition temperature TKT as well as the mass melting temperature T* as a function of the magnetic field. It is found that the pseudogap domain TKT < T < T* is enlarged with increasing strength of the magnetic field. The influence of a chiral imbalance or axial chemical potential μ5 is also studied. We find that even a constant axial chemical potential μ5 can lead to inverse magnetic catalysis of the KT transition temperature in 2+1 dimensions. As a result, the inverse magnetic catalysis behavior is actually the de Haas–van Alphen oscillation induced by the interplay between the magnetic field and the Fermi surface.

  16. The Fried Transdisciplinary Model of Technological and Social Organization of the Collection Establishment, Development, Maintenance, and Monitoring Process; An Operational Systems Approach for Diagnosing, Measuring, Evaluating, and Designing Improvements in Library Collection Building Organizational Policies and Practices.

    ERIC Educational Resources Information Center

    DeHart, Florence E.

    Jacob Fried and Paul Molnar developed a model to simulate the interaction between technological change and social interaction which consists of two zones: (1) task requisites; and (2) the corresponding organizational responses. To define task requisites for library collections, it is necessary to identify the dimensions of the problem and the…

  17. A model for the implementation of a two-shift municipal solid waste and recyclable material collection plan that offers greater convenience to residents.

    PubMed

    Lin, Hung-Yueh; Tsai, Zong-Pei; Chen, Guan-Hwa; Kao, Jehng-Jung

    2011-01-01

    Separating recyclables from municipal solid waste (MSW) before collection reduces not only the quantity of MSW that needs to be treated but also the depletion of resources. However, the participation of residents is essential for a successful recycling program, and the level of participation usually depends on the degree of convenience associated with accessing recycling collection points. The residential accessing convenience (RAC) of a collection plan is determined by the proximity of its collection points to all residents and its temporal flexibility in response to resident requirements. The degree of proximity to all residents is determined by using a coverage radius that represents the maximum distance residents need to travel to access a recycling point. The temporal flexibility is assessed by the availability of proximal recycling points at times suitable to the lifestyles of all residents concerned. In Taiwan, the MSW collection is implemented at fixed locations and at fixed times. Residents must deposit their garbage directly into the collection vehicle. To facilitate the assignment of collection vehicles and to encourage residents to thoroughly separate their recyclables, in Taiwan MSW and recyclable materials are usually collected at the same time by different vehicles. A heuristic procedure including an integer programming (IP) model and ant colony optimization (ACO) is explored in this study to determine an efficient two-shift collection plan that takes into account RAC factors. The IP model has been developed to determine convenient collection points in each shift on the basis of proximity, and then the ACO algorithm is applied to determine the most effective routing plan of each shift. With the use of a case study involving a city in Taiwan, this study has demonstrated that collection plans generated using the above procedure are superior to current collection plans on the basis of proximity and total collection distance.

  18. Numerical simulation of rock avalanches: Influence of a local dissipative contact model on the collective behavior of granular flows

    NASA Astrophysics Data System (ADS)

    Mollon, Guilhem; Richefeu, Vincent; Villard, Pascal; Daudon, Dominique

    2012-06-01

    Rock avalanches are a significant concern in developing mountain areas. Thus a reliable prediction of depositional areas from avalanches is needed. In order to improve the numerical modeling of such events and to provide information concerning the physical phenomena underlying this type of granular flow, a discrete element model, which takes into account frictional and collisional dissipation at grain scale together with angular-shaped elements, is used to investigate the collective behavior of granular masses propagating down a slope. The discrete element model (DEM) parameters are defined from drop tests involving the collision of an individual particle with a flat surface. The validity of the numerical model is estimated by comparison with the results of a laboratory experiment involving a dry granular flow on an inclined plane. The numerical model improves the understanding of rock avalanches by providing both valuable information about the way energy is dissipated either at the base or within the propagating granular mass and relevant information about the kinematics of the flow and the shape of the deposit. The influence of contact-law parameters is investigated using a sensitivity study. It is shown that the flow is strongly influenced by basal friction, while inter-particle friction and collisional dissipation phenomena intervene mostly in areas of flow perturbation (such as transition zones between two slopes). A macroscopic roughness of the slope surface induces an increased disorder in the particle motion which increases both frictional and collisional dissipation within the granular mass. Using a planar slope and increasing the frictional parameter can reproduce the apparent influence of this roughness.

  19. Collection Directions: The Evolution of Library Collections and Collecting

    ERIC Educational Resources Information Center

    Dempsey, Lorcan; Malpas, Constance; Lavoie, Brian

    2014-01-01

    This article takes a broad view of the evolution of collecting behaviors in a network environment and suggests some future directions based on various simple models. The authors look at the changing dynamics of print collections, at the greater engagement with research and learning behaviors, and at trends in scholarly communication. The goal is…

  20. Collective coordinate quantization and spin statistics of the solitons in the C PN Skyrme-Faddeev model

    NASA Astrophysics Data System (ADS)

    Amari, Yuki; Klimas, Paweł; Sawado, Nobuyuki

    2016-07-01

    The C PN extended Skyrme-Faddeev model possesses planar soliton solutions. We consider quantum aspects of the solutions applying collective coordinate quantization in regime of rigid body approximation. In order to discuss statistical properties of the solutions we include an Abelian Chern-Simons term (the Hopf term) in the Lagrangian. Since Π3(C P1)=Z then for N =1 the term becomes an integer. On the other hand for N >1 it became perturbative because Π3(C PN) is trivial. The prefactor of the Hopf term (anyon angle) Θ is not quantized and its value depends on the physical system. The corresponding fermionic models can fix value of the angle Θ for all N in a way that the soliton with N =1 is not an anyon type whereas for N >1 it is always an anyon even for Θ =n π , n ∈Z . We quantize the solutions and calculate several mass spectra for N =2 . Finally we discuss generalization for N ≧3 .

  1. Collectivity of the pygmy dipole resonance within schematic Tamm-Dancoff approximation and random-phase approximation models

    NASA Astrophysics Data System (ADS)

    Baran, V.; Palade, D. I.; Colonna, M.; Di Toro, M.; Croitoru, A.; Nicolin, A. I.

    2015-05-01

    Within schematic models based on the Tamm-Dancoff approximation and the random-phase approximation with separable interactions, we investigate the physical conditions that may determine the emergence of the pygmy dipole resonance in the E 1 response of atomic nuclei. By introducing a generalization of the Brown-Bolsterli schematic model with a density-dependent particle-hole residual interaction, we find that an additional mode will be affected by the interaction, whose energy centroid is closer to the distance between two major shells and therefore well below the giant dipole resonance (GDR). This state, together with the GDR, exhausts all the transition strength in the Tamm-Dancoff approximation and all the energy-weighted sum rule in the random-phase approximation. Thus, within our scheme, this mode, which could be associated with the pygmy dipole resonance, is of collective nature. By relating the coupling constants appearing in the separable interaction to the symmetry energy value at and below saturation density we explore the role of density dependence of the symmetry energy on the low-energy dipole response.

  2. Analysis of Diffusion-Controlled Dissolution from Polydisperse Collections of Drug Particles with an Assessed Mathematical Model.

    PubMed

    Wang, Yanxing; Abrahamsson, Bertil; Lindfors, Lennart; Brasseur, James G

    2015-09-01

    We introduce a "hierarchical" modeling strategy designed to be systematically extensible to increase the detail of dissolution predictions from polydisperse collections of drug particles and to be placed on firm mathematical and physical foundations with diffusion-dominated dissolution at its core to predict dissolution and the evolution of particle size distribution. We assess the model with experimental data and demonstrate higher accuracy by treating the polydisperse nature of dissolution. A level in the hierarchy is applied to study elements of diffusion-driven dissolution, in particular the role of particle-size distribution width with varying dose level and the influences of "confinement" on the process of dissolution. Confinement influences surface molecular flux, directly by the increase in bulk concentration and indirectly by the relative volume of particles to container. We find that the dissolution process can be broadly categorized within three "regimes" defined by the ratio of total concentration Ctot to solubility CS . Sink conditions apply in the first regime, when C tot /CS<∼0.1. When C tot /CS>∼5 (regime 3) dissolution is dominated by confinement and normalized saturation time follows a simple power law relationship. Regime 2 is characterized by a "saturation singularity" where dissolution is sensitive to both initial particle size distribution and confinement. PMID:25989144

  3. Can Government Be Self-Organized? A Mathematical Model of the Collective Social Organization of Ancient Teotihuacan, Central Mexico

    PubMed Central

    Froese, Tom; Gershenson, Carlos; Manzanilla, Linda R.

    2014-01-01

    Teotihuacan was the first urban civilization of Mesoamerica and one of the largest of the ancient world. Following a tradition in archaeology to equate social complexity with centralized hierarchy, it is widely believed that the city’s origin and growth was controlled by a lineage of powerful individuals. However, much data is indicative of a government of co-rulers, and artistic traditions expressed an egalitarian ideology. Yet this alternative keeps being marginalized because the problems of collective action make it difficult to conceive how such a coalition could have functioned in principle. We therefore devised a mathematical model of the city’s hypothetical network of representatives as a formal proof of concept that widespread cooperation was realizable in a fully distributed manner. In the model, decisions become self-organized into globally optimal configurations even though local representatives behave and modify their relations in a rational and selfish manner. This self-optimization crucially depends on occasional communal interruptions of normal activity, and it is impeded when sections of the network are too independent. We relate these insights to theories about community-wide rituals at Teotihuacan and the city’s eventual disintegration. PMID:25303308

  4. Can government be self-organized? A mathematical model of the collective social organization of ancient Teotihuacan, central Mexico.

    PubMed

    Froese, Tom; Gershenson, Carlos; Manzanilla, Linda R

    2014-01-01

    Teotihuacan was the first urban civilization of Mesoamerica and one of the largest of the ancient world. Following a tradition in archaeology to equate social complexity with centralized hierarchy, it is widely believed that the city's origin and growth was controlled by a lineage of powerful individuals. However, much data is indicative of a government of co-rulers, and artistic traditions expressed an egalitarian ideology. Yet this alternative keeps being marginalized because the problems of collective action make it difficult to conceive how such a coalition could have functioned in principle. We therefore devised a mathematical model of the city's hypothetical network of representatives as a formal proof of concept that widespread cooperation was realizable in a fully distributed manner. In the model, decisions become self-organized into globally optimal configurations even though local representatives behave and modify their relations in a rational and selfish manner. This self-optimization crucially depends on occasional communal interruptions of normal activity, and it is impeded when sections of the network are too independent. We relate these insights to theories about community-wide rituals at Teotihuacan and the city's eventual disintegration.

  5. Can government be self-organized? A mathematical model of the collective social organization of ancient Teotihuacan, central Mexico.

    PubMed

    Froese, Tom; Gershenson, Carlos; Manzanilla, Linda R

    2014-01-01

    Teotihuacan was the first urban civilization of Mesoamerica and one of the largest of the ancient world. Following a tradition in archaeology to equate social complexity with centralized hierarchy, it is widely believed that the city's origin and growth was controlled by a lineage of powerful individuals. However, much data is indicative of a government of co-rulers, and artistic traditions expressed an egalitarian ideology. Yet this alternative keeps being marginalized because the problems of collective action make it difficult to conceive how such a coalition could have functioned in principle. We therefore devised a mathematical model of the city's hypothetical network of representatives as a formal proof of concept that widespread cooperation was realizable in a fully distributed manner. In the model, decisions become self-organized into globally optimal configurations even though local representatives behave and modify their relations in a rational and selfish manner. This self-optimization crucially depends on occasional communal interruptions of normal activity, and it is impeded when sections of the network are too independent. We relate these insights to theories about community-wide rituals at Teotihuacan and the city's eventual disintegration. PMID:25303308

  6. Analysis of Diffusion-Controlled Dissolution from Polydisperse Collections of Drug Particles with an Assessed Mathematical Model.

    PubMed

    Wang, Yanxing; Abrahamsson, Bertil; Lindfors, Lennart; Brasseur, James G

    2015-09-01

    We introduce a "hierarchical" modeling strategy designed to be systematically extensible to increase the detail of dissolution predictions from polydisperse collections of drug particles and to be placed on firm mathematical and physical foundations with diffusion-dominated dissolution at its core to predict dissolution and the evolution of particle size distribution. We assess the model with experimental data and demonstrate higher accuracy by treating the polydisperse nature of dissolution. A level in the hierarchy is applied to study elements of diffusion-driven dissolution, in particular the role of particle-size distribution width with varying dose level and the influences of "confinement" on the process of dissolution. Confinement influences surface molecular flux, directly by the increase in bulk concentration and indirectly by the relative volume of particles to container. We find that the dissolution process can be broadly categorized within three "regimes" defined by the ratio of total concentration Ctot to solubility CS . Sink conditions apply in the first regime, when C tot /CS<∼0.1. When C tot /CS>∼5 (regime 3) dissolution is dominated by confinement and normalized saturation time follows a simple power law relationship. Regime 2 is characterized by a "saturation singularity" where dissolution is sensitive to both initial particle size distribution and confinement.

  7. Evaluating the efficiency of municipalities in collecting and processing municipal solid waste: A shared input DEA-model

    SciTech Connect

    Rogge, Nicky; De Jaeger, Simon

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Complexity in local waste management calls for more in depth efficiency analysis. Black-Right-Pointing-Pointer Shared-input Data Envelopment Analysis can provide solution. Black-Right-Pointing-Pointer Considerable room for the Flemish municipalities to improve their cost efficiency. - Abstract: This paper proposed an adjusted 'shared-input' version of the popular efficiency measurement technique Data Envelopment Analysis (DEA) that enables evaluating municipality waste collection and processing performances in settings in which one input (waste costs) is shared among treatment efforts of multiple municipal solid waste fractions. The main advantage of this version of DEA is that it not only provides an estimate of the municipalities overall cost efficiency but also estimates of the municipalities' cost efficiency in the treatment of the different fractions of municipal solid waste (MSW). To illustrate the practical usefulness of the shared input DEA-model, we apply the model to data on 293 municipalities in Flanders, Belgium, for the year 2008.

  8. Method to Rapidly Collect Thousands of Velocity Observations to Validate Million-Element 2D Hydrodynamic Models

    NASA Astrophysics Data System (ADS)

    Barker, J. R.; Pasternack, G. B.; Bratovich, P.; Massa, D.; Reedy, G.; Johnson, T.

    2010-12-01

    Two-dimensional (depth-averaged) hydrodynamic models have existed for decades and are used to study a variety of hydrogeomorphic processes as well as to design river rehabilitation projects. Rapid computer and coding advances are revolutionizing the size and detail of 2D models. Meanwhile, advances in topo mapping and environmental informatics are providing the data inputs to drive large, detailed simulations. Million-element computational meshes are in hand. With simulations of this size and detail, the primary challenge has shifted to finding rapid and inexpensive means for testing model predictions against observations. Standard methods for collecting velocity data include boat-mounted ADCP and point-based sensors on boats or wading rods. These methods are labor intensive and often limited to a narrow flow range. Also, they generate small datasets at a few cross-sections, which is inadequate to characterize the statistical structure of the relation between predictions and observations. Drawing on the long-standing oceanographic method of using drogues to track water currents, previous studies have demonstrated the potential of small dGPS units to obtain surface velocity in rivers. However, dGPS is too inaccurate to test 2D models. Also, there is financial risk in losing drogues in rough currents. In this study, an RTK GPS unit was mounted onto a manned whitewater kayak. The boater positioned himself into the current and used floating debris to maintain a speed and heading consistent with the ambient surface flow field. RTK GPS measurements were taken ever 5 sec. From these positions, a 2D velocity vector was obtained. The method was tested over ~20 km of the lower Yuba River in California in flows ranging from 500-5000 cfs, yielding 5816 observations. To compare velocity magnitude against the 2D model-predicted depth-averaged value, kayak-based surface values were scaled down by an optimized constant (0.72), which had no negative effect on regression analysis

  9. Local know model of entangled polyme chains. 1. Computer simulations of local knots and their collective motion

    SciTech Connect

    Iwata, Kazuyoshi; Tanaka, Mitsuya

    1992-05-14

    The local know (LK) theory recently proposed is confirmed by computer simulations of entangled ring polymer chains. The simple cubic lattice model chains (ring) of length L = 512 (volume fraction c = 0.5) is used. By tracing local maxima of Gauss integral along polymer chains, many {open_quotes}true{close_quotes} LKs (lifetime {tau}{sub true}={infinity}) and {open_quotes}temporary{close_quotes} LKs (lifetime {tau}{sub temp} = 2.3 Mu.t;u.t. = unit of time) are found. It is observed that the orders of true and temporary LKs along rings are conserved and that they perform a collective motion (reptation) as predicted by the theory. Various strange motions of true LKs, such as {open_quotes}merging effect{close_quotes}, {open_quotes}multipeak effect{close_quotes}, {open_quotes}ghost effect{close_quotes}, and {open_quotes}probe fluctuations{close_quotes}, are found. In this (part 1) and the following paper (part 2), we discuss in detail how to separate the true Markov motion of LKs and their collective motions from these non-Markov motions. The average number of true and temporary LKs per ring (L = 512) are estimated to be {bar n}{sub true} = 3.44 and {bar n}{sub temp} = 3.0{sub 6}. The average chain length per true LKs is L{sub true} = 149. The diffusion coefficient of single LK is estimated to be d{sub 0} = 0.0172 bond{sup 2}/u.t. The mean-square displacement of LK coordinate {xi} along a ring, g(t) = ({xi}(t) - {xi}(0)){sup 2}, approaches the Markov line computed for the diffusion coefficient d{sub 0}/({bar n}{sub true} + {bar n}{sub temp}); this suggests that the temporary LKs join to the collective motion of LKs. The empirical entanglement spacing n{sub e} of this system is estimated to be 230 or slightly less; this n{sub e} = 120-133 estimated by Skolnick et al. 26 refs., 16 figs., 6 tabs.

  10. A Collective Case Study of Secondary Students' Model-Based Inquiry on Natural Selection through Programming in an Agent-Based Modeling Environment

    NASA Astrophysics Data System (ADS)

    Xiang, Lin

    This is a collective case study seeking to develop detailed descriptions of how programming an agent-based simulation influences a group of 8 th grade students' model-based inquiry (MBI) by examining students' agent-based programmable modeling (ABPM) processes and the learning outcomes. The context of the present study was a biology unit on natural selection implemented in a charter school of a major California city during spring semester of 2009. Eight 8th grade students, two boys and six girls, participated in this study. All of them were low socioeconomic status (SES). English was a second language for all of them, but they had been identified as fluent English speakers at least a year before the study. None of them had learned either natural selection or programming before the study. The study spanned over 7 weeks and was comprised of two study phases. In phase one the subject students learned natural selection in science classroom and how to do programming in NetLogo, an ABPM tool, in a computer lab; in phase two, the subject students were asked to program a simulation of adaptation based on the natural selection model in NetLogo. Both qualitative and quantitative data were collected in this study. The data resources included (1) pre and post test questionnaire, (2) student in-class worksheet, (3) programming planning sheet, (4) code-conception matching sheet, (5) student NetLogo projects, (6) videotaped programming processes, (7) final interview, and (8) investigator's field notes. Both qualitative and quantitative approaches were applied to analyze the gathered data. The findings suggested that students made progress on understanding adaptation phenomena and natural selection at the end of ABPM-supported MBI learning but the progress was limited. These students still held some misconceptions in their conceptual models, such as the idea that animals need to "learn" to adapt into the environment. Besides, their models of natural selection appeared to be

  11. Collection Development.

    ERIC Educational Resources Information Center

    School Libraries in Canada, 2002

    2002-01-01

    Includes 21 articles that discuss collection development in Canadian school libraries. Topics include digital collections in school library media centers; print and electronic library resources; library collections; collaborative projects; print-disabled students; informing administrators of the importance of collection development; censorship;…

  12. The Collective Impact Model and Its Potential for Health Promotion: Overview and Case Study of a Healthy Retail Initiative in San Francisco

    ERIC Educational Resources Information Center

    Flood, Johnna; Minkler, Meredith; Lavery, Susana Hennessey; Estrada, Jessica; Falbe, Jennifer

    2015-01-01

    As resources for health promotion become more constricted, it is increasingly important to collaborate across sectors, including the private sector. Although many excellent models for cross-sector collaboration have shown promise in the health field, collective impact (CI), an emerging model for creating larger scale change, has yet to receive…

  13. Methods for using groundwater model predictions to guide hydrogeologic data collection, with application to the Death Valley regional groundwater flow system

    USGS Publications Warehouse

    Tiedeman, C.R.; Hill, M.C.; D'Agnese, F. A.; Faunt, C.C.

    2003-01-01

    Calibrated models of groundwater systems can provide substantial information for guiding data collection. This work considers using such models to guide hydrogeologic data collection for improving model predictions by identifying model parameters that are most important to the predictions. Identification of these important parameters can help guide collection of field data about parameter values and associated flow system features and can lead to improved predictions. Methods for identifying parameters important to predictions include prediction scaled sensitivities (PSS), which account for uncertainty on individual parameters as well as prediction sensitivity to parameters, and a new "value of improved information" (VOII) method presented here, which includes the effects of parameter correlation in addition to individual parameter uncertainty and prediction sensitivity. In this work, the PSS and VOII methods are demonstrated and evaluated using a model of the Death Valley regional groundwater flow system. The predictions of interest are advective transport paths originating at sites of past underground nuclear testing. Results show that for two paths evaluated the most important parameters include a subset of five or six of the 23 defined model parameters. Some of the parameters identified as most important are associated with flow system attributes that do not lie in the immediate vicinity of the paths. Results also indicate that the PSS and VOII methods can identify different important parameters. Because the methods emphasize somewhat different criteria for parameter importance, it is suggested that parameters identified by both methods be carefully considered in subsequent data collection efforts aimed at improving model predictions.

  14. An ISA-TAB-Nano based data collection framework to support data-driven modelling of nanotoxicology.

    PubMed

    Marchese Robinson, Richard L; Cronin, Mark T D; Richarz, Andrea-Nicole; Rallo, Robert

    2015-01-01

    Analysis of trends in nanotoxicology data and the development of data driven models for nanotoxicity is facilitated by the reporting of data using a standardised electronic format. ISA-TAB-Nano has been proposed as such a format. However, in order to build useful datasets according to this format, a variety of issues has to be addressed. These issues include questions regarding exactly which (meta)data to report and how to report them. The current article discusses some of the challenges associated with the use of ISA-TAB-Nano and presents a set of resources designed to facilitate the manual creation of ISA-TAB-Nano datasets from the nanotoxicology literature. These resources were developed within the context of the NanoPUZZLES EU project and include data collection templates, corresponding business rules that extend the generic ISA-TAB-Nano specification as well as Python code to facilitate parsing and integration of these datasets within other nanoinformatics resources. The use of these resources is illustrated by a "Toy Dataset" presented in the Supporting Information. The strengths and weaknesses of the resources are discussed along with possible future developments.

  15. An ISA-TAB-Nano based data collection framework to support data-driven modelling of nanotoxicology

    PubMed Central

    Marchese Robinson, Richard L; Richarz, Andrea-Nicole; Rallo, Robert

    2015-01-01

    Summary Analysis of trends in nanotoxicology data and the development of data driven models for nanotoxicity is facilitated by the reporting of data using a standardised electronic format. ISA-TAB-Nano has been proposed as such a format. However, in order to build useful datasets according to this format, a variety of issues has to be addressed. These issues include questions regarding exactly which (meta)data to report and how to report them. The current article discusses some of the challenges associated with the use of ISA-TAB-Nano and presents a set of resources designed to facilitate the manual creation of ISA-TAB-Nano datasets from the nanotoxicology literature. These resources were developed within the context of the NanoPUZZLES EU project and include data collection templates, corresponding business rules that extend the generic ISA-TAB-Nano specification as well as Python code to facilitate parsing and integration of these datasets within other nanoinformatics resources. The use of these resources is illustrated by a “Toy Dataset” presented in the Supporting Information. The strengths and weaknesses of the resources are discussed along with possible future developments. PMID:26665069

  16. An ISA-TAB-Nano based data collection framework to support data-driven modelling of nanotoxicology.

    PubMed

    Marchese Robinson, Richard L; Cronin, Mark T D; Richarz, Andrea-Nicole; Rallo, Robert

    2015-01-01

    Analysis of trends in nanotoxicology data and the development of data driven models for nanotoxicity is facilitated by the reporting of data using a standardised electronic format. ISA-TAB-Nano has been proposed as such a format. However, in order to build useful datasets according to this format, a variety of issues has to be addressed. These issues include questions regarding exactly which (meta)data to report and how to report them. The current article discusses some of the challenges associated with the use of ISA-TAB-Nano and presents a set of resources designed to facilitate the manual creation of ISA-TAB-Nano datasets from the nanotoxicology literature. These resources were developed within the context of the NanoPUZZLES EU project and include data collection templates, corresponding business rules that extend the generic ISA-TAB-Nano specification as well as Python code to facilitate parsing and integration of these datasets within other nanoinformatics resources. The use of these resources is illustrated by a "Toy Dataset" presented in the Supporting Information. The strengths and weaknesses of the resources are discussed along with possible future developments. PMID:26665069

  17. Modeling the inflammatory response in the hypothalamus ensuing heat stroke: iterative cycle of model calibration, identifiability analysis, experimental design and data collection.

    PubMed

    Klett, Hagen; Rodriguez-Fernandez, Maria; Dineen, Shauna; Leon, Lisa R; Timmer, Jens; Doyle, Francis J

    2015-02-01

    Heat Stroke (HS) is a life-threatening illness caused by prolonged exposure to heat that causes severe hyperthermia and nervous system abnormalities. The long term consequences of HS are poorly understood and deeper insight is required to find possible treatment strategies. Elevated pro- and anti-inflammatory cytokines during HS recovery suggest to play a major role in the immune response. In this study, we developed a mathematical model to understand the interactions and dynamics of cytokines in the hypothalamus, the main thermoregulatory center in the brain. Uncertainty and identifiability analysis of the calibrated model parameters revealed non-identifiable parameters due to the limited amount of data. To overcome the lack of identifiability of the parameters, an iterative cycle of optimal experimental design, data collection, re-calibration and model reduction was applied and further informative experiments were suggested. Additionally, a new method of approximating the prior distribution of the parameters for Bayesian optimal experimental design based on the profile likelihood is presented.

  18. MODEL IMPLEMENTATION TO EVALUATE THE COLLECTIVE FUTURE RADIONUCLIDE RELEASES FROM MULTIPLE FACILITIES AT THE SAVANNAH RIVER SITE

    SciTech Connect

    Hiergesell, R.; Smith, F.; Hamm, L.; Phifer, M.; Swingle, R.

    2009-12-15

    A comprehensive Composite Analysis (CA) has been performed considering 152 sources of residual radioactive material at the Savannah River Site (SRS). As part of the CA a model was developed to perform deterministic base case calculations using the commercial GoldSim software. The model treated transport and decay of radionuclides as they are released at the source location and transported through the source region, vadose zone and aquifer to stream outcrops and from there to the Savannah River. A dose to the public was calculated assuming recreational use of stream water and residential use of river water. The specific results from the GoldSim modeling evaluation conducted as part of the CA indicate that the collective maximum dose resulting from the release of radionuclides from all 152 anticipated SRS End State sources of residual radionuclides demonstrate that maximum exposures expected to occur to any offsite MOP will not approach the 300 uSv/yr (30 mrem/yr) dose constraint, and in fact are currently estimated to be only 10% of this. For each of the POA's evaluated, the highest cumulative dose is realized at the Lower Three Runs POA and is calculated to be 29.7 uSv/yr (2.97 mrem/yr). The major dose contributing radionuclide for all of the POA's, with the exception of Upper Three Runs, was {sup 137}Cs in the contaminated streambed sediments. In Upper Three Runs {sup 237}Np from the H-Area Canyon Building was the major dose contributing radionuclide. The major exposure pathway for the SRS streams (where the Recreational Scenario was evaluated) was by the ingestion of fish. In the Savannah River, where the Residential Scenario was evaluated, ingestion of vegetation was the dominant exposure pathway. The uncertainty evaluation lends added assurance to the conclusion that the 30 mrem/yr dose constraint will not be exceeded, in that even at the 95th Percentile, this performance measure is not expected to be exceeded. It must also be added that these conclusions

  19. Collecting apparatus

    DOEpatents

    Duncan, Charles P.

    1983-01-01

    An improved collecting apparatus for small aquatic or airborne organisms such as plankton, larval fish, insects, etc. The improvement constitutes an apertured removal container within which is retained a collecting bag, and which is secured at the apex of a conical collecting net. Such collectors are towed behind a vessel or vehicle with the open end of the conical net facing forward for trapping the aquatic or airborne organisms within the collecting bag, while allowing the water or air to pass through the apertures in the container. The container is readily removable from the collecting net whereby the collecting bag can be quickly removed and replaced for further sample collection. The collecting bag is provided with means for preventing the bag from being pulled into the container by the water or air flowing therethrough.

  20. Proposal of a new model to improve the collection of small WEEE: a pilot project for the recovery and recycling of toys.

    PubMed

    Solé, Miquel; Watson, Jenna; Puig, Rita; Fullana-i-Palmer, Pere

    2012-11-01

    A new collection model was designed and tested in Catalonia (Spain) to foster the separate collection and recycling of electrical and electronic toys, with the participation of selected primary and secondary schools, as well as waste collection points and municipalities. This project approach is very original and important because small household WEEE has low rates of collection (16-21% WEEE within the EU or 5-7% WEEE in Spain) and no research on new approaches to enhance the collection of small WEEE is found in the literature. The project was successful in achieving enhanced toys collection and recycling rates, which went up from the national Spanish average of 0.5% toys before the project to 1.9 and 6% toys during the two project years, respectively. The environmental benefits of the campaign were calculated through a life-cycle approach, accounting for the avoided impact afforded by the reuse of the toys and the recycling of the valuable materials contained therein (such as metals, batteries and circuit boards) and subtracting the additional environmental burdens associated with the establishment of the collection campaign.

  1. Assessing the performance of gas collection systems in select Chinese landfills according to the LandGEM model: drawbacks and potential direction.

    PubMed

    Sun, Yue; Yue, Dongbei; Li, Rundong; Yang, Ting; Liu, Shiliang

    2015-01-01

    In China, municipal solid waste (MSW) is primarily treated by landfilling. Landfill gas (LFG) collection effectively reduces methane emission from MSW landfills. An accurate system of LFG collection is important in landfill planning, design, and operation. However, China has not developed such systems. In this study, the efficiency of methane collection is calculated in three Chinese landfills with different collection systems (A: vertical wells for MSW before 2010; combined horizontal trenches and under-membrane pipes for MSW from 2011 onwards; B: combined horizontal trenches and vertical wells; C: vertical wells only). This efficiency was computed by dividing the quantity of methane obtained from landfill operation records by the quantity estimated based on the LandGEM model. Results show that the collection efficiencies of landfills with vertical wells and/or horizontal pipes ranged from 8.3% to 27.9%, whereas those of a system equipped with geomembrane reached 65.3%. The poor performance of the landfills was attributed to the open burning of early-stage LFG, LFG release from cracks in high-density polyethylene covers, and high levels of leachate within a landfill site. Therefore, this study proposes an integrated LFG collection system that can remove leachate and collect gas from landfills that accept waste with high moisture content. PMID:26510610

  2. Collection Mapping and Collection Development.

    ERIC Educational Resources Information Center

    Murray, William; And Others

    1985-01-01

    Describes the use of collection mapping to assess media collections of Aurora, Colorado, Public Schools. Case studies of elementary, middle, and high school media centers describe materials selection and weeding and identify philosophies that library collections should support school curriculum, and teacher-library media specialist cooperation in…

  3. Kinetic models - mathematical models of everything?. Comment on "Collective learning modeling based on the kinetic theory of active particles" by D. Burini et al.

    NASA Astrophysics Data System (ADS)

    Banasiak, J.

    2016-03-01

    Since the emergence of systematic science it has been recognized that a natural phenomenon can be described by different models that vary in their complexity and their ability to capture the details of the features relevant at the required level of the resolution. It has been tacitly assumed that whenever two such models are applicable at the same level, they must provide equivalent descriptions of the phenomenon. One of the earliest and most celebrated examples of this type is offered by gas flow which can be described either by the Boltzmann equation at a suitably understood molecular level or by the Euler or Navier-Stokes equations at the level of continuum. More precisely, the flow of a gas as a continuous medium, or, in other words, at the macro level, can be explained in more detail by analysing elementary collisions between pairs of molecules. Thus, the Boltzmann equation is often recognized as a more detailed equation of gas at the so-called mesoscopic, or kinetic, level from which macroscopic properties of gas, such as density, momentum or temperature, can be derived. It should be noted that one can model gas at an even more fundamental, or micro, level by tracing the motion of individual molecules by solving the system of the Newton equations that describe their interactions, [11].

  4. Membership in a Devalued Social Group and Emotional Well-Being: Developing a Model of Personal Self-Esteem, Collective Self-Esteem, and Group Socialization.

    ERIC Educational Resources Information Center

    Katz, Jennifer; Joiner, Thomas E., Jr.; Kwon, Paul

    2002-01-01

    Tested a theoretical model that linked membership in a devalued social group to emotional health. Surveyed white, middle-to-upper-class undergraduate students regarding personal and collective self-esteem (by gender), attitudes and behaviors associated with female socialization, and emotional distress. Results supported the direct effect of each…

  5. EVALUATION OF THE CMB AND PMF MODELS USING ORGANIC MOLECULAR MARKERS IN FINE PARTICULATE MATTER COLLECTED DURING THE PITTSBURGH AIR QUALITY STUDY

    EPA Science Inventory

    This research investigated different strategies for source apportionment of airborne fine particulate matter (PM2.5) collected as part of the Pittsburgh Air Quality Study. Two source receptor models were used, the EPA Chemical Mass Balance 8.2 (CMB) and EPA Positive Matrix Facto...

  6. Study on Commercialization of Biogasification Systems in Ishikari Bay New Port Area - Proposal of Estimation Method of Collectable Amount of Food Waste by using Binary Logit Model -

    NASA Astrophysics Data System (ADS)

    Watanabe, Sho; Furuichi, Toru; Ishii, Kazuei

    This study proposed an estimation method for collectable amount of food waste considering the food waste generator's cooperation ratio ant the amount of food waste generation, and clarified the factors influencing the collectable amount of food waste. In our method, the cooperation ratio was calculated by using the binary logit model which is often used for the traffic multiple choice question. In order to develop a more precise binary logit model, the factors influencing on the cooperation ratio were extracted by a questionnaire survey asking food waste generator's intention, and the preference investigation was then conducted at the second step. As a result, the collectable amount of food waste was estimated to be 72 [t/day] in the Ishikari bay new port area under a condition of current collection system by using our method. In addition, the most critical factor influencing on the collectable amount of food waste was the treatment fee for households, and was the permitted mixture degree of improper materials for retail trade and restaurant businesses

  7. Collecting Rocks.

    ERIC Educational Resources Information Center

    Barker, Rachel M.

    One of a series of general interest publications on science topics, the booklet provides those interested in rock collecting with a nontechnical introduction to the subject. Following a section examining the nature and formation of igneous, sedimentary, and metamorphic rocks, the booklet gives suggestions for starting a rock collection and using…

  8. Collective Enumeration

    ERIC Educational Resources Information Center

    Bahrami, Bahador; Didino, Daniele; Frith, Chris; Butterworth, Brian; Rees, Geraint

    2013-01-01

    Many joint decisions in everyday life (e.g., Which bar is less crowded?) depend on approximate enumeration, but very little is known about the psychological characteristics of counting together. Here we systematically investigated collective approximate enumeration. Pairs of participants made individual and collective enumeration judgments in a…

  9. Jay's Collectibles

    ERIC Educational Resources Information Center

    Cappel, James J.; Gillman, Jason R., Jr.

    2011-01-01

    There is growing interest in collectibles of many types, as indicated by the popularity of television programs such as the History Channel's "Pawn Stars" and "American Pickers" and the Public Broadcasting Service's "Antiques Road Show." The availability of online auction sites such as eBay has enabled many people to collect items of interest as a…

  10. Insights from socio-hydrology modelling on dealing with flood risk - Roles of collective memory, risk-taking attitude and trust

    NASA Astrophysics Data System (ADS)

    Viglione, Alberto; Di Baldassarre, Giuliano; Brandimarte, Luigia; Kuil, Linda; Carr, Gemma; Salinas, José Luis; Scolobig, Anna; Blöschl, Günter

    2014-10-01

    The risk coping culture of a community plays a major role in the development of urban floodplains. In this paper we analyse, in a conceptual way, the interplay of community risk coping culture, flooding damage and economic growth. We particularly focus on three aspects: (i) collective memory, i.e., the capacity of the community to keep risk awareness high; (ii) risk-taking attitude, i.e., the amount of risk the community is collectively willing to be exposed to; and (iii) trust of the community in risk reduction measures. To this end, we use a dynamic model that represents the feedback between the hydrological and social system components. Model results indicate that, on the one hand, by under perceiving the risk of flooding (because of short collective memory and too much trust in flood protection structures) in combination with a high risk-taking attitude, community development is severely limited because of high damages caused by flooding. On the other hand, overestimation of risk (long memory and lack of trust in flood protection structures) leads to lost economic opportunities and recession. There are many scenarios of favourable development resulting from a trade-off between collective memory and trust in risk reduction measures combined with a low to moderate risk-taking attitude. Interestingly, the model gives rise to situations in which the development of the community in the floodplain is path dependent, i.e., the history of flooding may lead to community growth or recession.

  11. Culture collections.

    PubMed

    Smith, David

    2012-01-01

    Culture collections no matter their size, form, or institutional objectives play a role in underpinning microbiology, supplying the resources for study, innovation, and discovery. Their basic roles include providing a mechanism for ex situ conservation of organisms; they are repositories for strains subject to publication, taking in safe, confidential, and patent deposits from researchers. They supply strains for use; therefore, the microorganisms provided must be authentic and preserved well, and any associated information must be valid and sufficient to facilitate the confirmation of their identity and to facilitate their use. The organisms must be collected in compliance with international conventions, international and national legislation and distributed to users indicating clearly the terms and conditions under which they are received and can be used. Collections are harmonizing approaches and characterizing strains to meet user needs. No one single collection can carry out this task alone, and therefore, it is important that output and strategy are coordinated to ensure culture collections deliver the basic resources and services microbiological innovation requires. This chapter describes the types of collection and how they can implement quality management systems and operate to deliver their basic functions. The links to information sources given not only provide support for the practitioners within collections but also provide guidance to users on accessing the huge resource available and how they can help ensure microbiology has the resources and a solid platform for future development.

  12. Micrometeorite Collecting

    ERIC Educational Resources Information Center

    Toubes, Joe; Hoff, Darrel

    1974-01-01

    Describes how to collect micrometeorites and suggests a number of related activities such as determining the number of meteors entering the atmosphere and determining the composition of the micrometeorites. (BR)

  13. Comparative study of spectral diffuse-only and diffuse-specular radiative transfer models and field-collected data in the LWIR

    NASA Astrophysics Data System (ADS)

    Stoyanov, Dimitar M.; Marciniak, Michael A.; Meola, Joseph

    2015-09-01

    The sensitivity of hyper-spectral remote sensing to the directional reflectance of surfaces was studied using both laboratory and field measurements. Namely, the effects of the specular- and diffuse-reflectance properties of a set of eight samples, ranging from high to low in both total reflectance and specularity, on diffuse-only and diffusespecular radiative transfer models in the long-wave infrared (LWIR, 7-14-μm wavelength) were studied. The samples were measured in the field as a set of eight panels, each in two orientations, with surface normal pointing toward zenith and tipped at 45° from zenith. The field-collected data also included down-welling spectral sky radiance at several angles from zenith to the horizon, ground spectral radiance, panel spectral radiances in both orientations, Infragold® spectral radiances in both orientations near each panel location, and panel temperatures. Laboratory measurements included spectral hemispherical, specular and diffuse directional reflectance (HDR, SDR and DDR) for each sample for several reflectance angles with respect to the surface normal. The diffuse-only radiative transfer model used the HDR data, while the diffuse-specular model used the SDR and DDR data. Both calculated spectral reflected and self-emitted radiances for each panel, using the field-collected sky radiance data to avoid uncertainties associated with atmospheric models. The modeled spectral radiances were then compared to the field-collected values to quantify differences in moving from an HDR-based model to an SDR/DDR model in the LWIR for a variety of surface-reflectance types.

  14. Investment into the future of microbial resources: culture collection funding models and BRC business plans for biological resource centres.

    PubMed

    Smith, David; McCluskey, Kevin; Stackebrandt, Erko

    2014-01-01

    Through their long history of public service, diverse microbial Biological Resource Centres (mBRCs) have made myriad contributions to society and science. They have enabled the maintenance of specimens isolated before antibiotics, made available strains showing the development and change of pathogenicity toward animals, humans and plants, and have maintained and provided reference strains to ensure quality and reproducibility of science. However, this has not been achieved without considerable financial commitment. Different collections have unique histories and their support is often tied to their origins. However many collections have grown to serve large constituencies and need to develop novel funding mechanisms. Moreover, several international initiatives have described mBRCs as a factor in economic development and have led to the increased professionalism among mBRCs.

  15. Numerical simulations on active rod like particles as a model for the collective behavior of Myxococcus xanthus

    NASA Astrophysics Data System (ADS)

    Wigbers, Manon; Thutupalli, Shashi; Shaevitz, Joshua

    2015-03-01

    We study collective behavior of Myxococcus xanthus using numerical simulations. Under starvation conditions, these social bacteria organize into multi-cellular structures, called ``fruiting bodies,'' within which cells sporulate. During the process of fruiting body formation, cells show various collective motion patterns. One of the most striking of these patterns is the so called rippling motility, characterized by standing density waves of reversing bacteria. Similar rippling behaviour is also observed during predatory feeding of the bacteria. Until now, the principles underlying this rippling behavior are not fully elucidated. Analogous to the well studied liquid crystalline phases in condensed matter physics, the ordering of the baceria within these rippling waves resembles a smectic like layered structure. In contrast to active nematic liquid crystalline phases widely studied in recent times, this represents the first known empirical example of an active smectic phase. Inspired by single-cell resolution experimental data of the bacteria, we develop a modelof active rod like particles and use numerical simulations to study the organizing principles that drive the transitions between the various active liquid crystalline phases in the myxobacterial collective behavior.

  16. Bio-AIMS Collection of Chemoinformatics Web Tools based on Molecular Graph Information and Artificial Intelligence Models.

    PubMed

    Munteanu, Cristian R; Gonzalez-Diaz, Humberto; Garcia, Rafael; Loza, Mabel; Pazos, Alejandro

    2015-01-01

    The molecular information encoding into molecular descriptors is the first step into in silico Chemoinformatics methods in Drug Design. The Machine Learning methods are a complex solution to find prediction models for specific biological properties of molecules. These models connect the molecular structure information such as atom connectivity (molecular graphs) or physical-chemical properties of an atom/group of atoms to the molecular activity (Quantitative Structure - Activity Relationship, QSAR). Due to the complexity of the proteins, the prediction of their activity is a complicated task and the interpretation of the models is more difficult. The current review presents a series of 11 prediction models for proteins, implemented as free Web tools on an Artificial Intelligence Model Server in Biosciences, Bio-AIMS (http://bio-aims.udc.es/TargetPred.php). Six tools predict protein activity, two models evaluate drug - protein target interactions and the other three calculate protein - protein interactions. The input information is based on the protein 3D structure for nine models, 1D peptide amino acid sequence for three tools and drug SMILES formulas for two servers. The molecular graph descriptor-based Machine Learning models could be useful tools for in silico screening of new peptides/proteins as future drug targets for specific treatments.

  17. Using Physical and Computer Simulations of Collective Behaviour as an Introduction to Modelling Concepts for Applied Biologists

    ERIC Educational Resources Information Center

    Rands, Sean A.

    2012-01-01

    Models are an important tool in science: not only do they act as a convenient device for describing a system or problem, but they also act as a conceptual tool for framing and exploring hypotheses. Models, and in particular computer simulations, are also an important education tool for training scientists, but it is difficult to teach students the…

  18. A Prototype Digital Library for 3D Collections: Tools To Capture, Model, Analyze, and Query Complex 3D Data.

    ERIC Educational Resources Information Center

    Rowe, Jeremy; Razdan, Anshuman

    The Partnership for Research in Spatial Modeling (PRISM) project at Arizona State University (ASU) developed modeling and analytic tools to respond to the limitations of two-dimensional (2D) data representations perceived by affiliated discipline scientists, and to take advantage of the enhanced capabilities of three-dimensional (3D) data that…

  19. Blood Collection

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The method that is used for the collection, storage and real-time analysis of blood and other bodily fluids has been licensed to DBCD, Inc. by NASA. The result of this patent licensing agreement has been the development of a commercial product that can provide serum or plasma from whole blood volumes of 20 microliters to 4 milliliters. The device has a fibrous filter with a pore size of less than about 3 microns, and is coated with a mixture of mannitol and plasma fraction protein. The coating causes the cellular fraction to be trapped by the small pores, leaving the cellular fraction intact on the fibrous filter while the acellular fraction passes through the filter for collection in unaltered form from the serum sample collection chamber. The method used by this product is useful to NASA for blood analysis on manned space missions.

  20. Failure Orientation in Stretch Forming and Its Correlation with a Polycrystal Plasticity-Based Material Model for a Collection of Highly Formable Sheet Steels

    NASA Astrophysics Data System (ADS)

    An, Yuguo; Boterman, Romke; Atzema, Eisso; Abspoel, Michael; Scholting, Marc

    2016-07-01

    Robust design optimization techniques have been developed in recent years within the automotive industry with the aim of reducing scrap rates and improving process stability in sheet metal forming. These new techniques are able to take process variations and other sources of material scatter into account. Among the many material variables and inputs used, the yield criterion is an important aspect and this is used to describe the plastic behavior of sheet metals. To achieve a reliable output in an optimization study, the yield criterion selected must be representative of material response and scatter. However, simple material models that deviate from real material behavior are often used due to a lack of material data, which is usually a requirement when using more complex models. In the present research, a polycrystal plasticity-based CTFP model has been evaluated in stretch forming for a collection of highly formable sheet steel materials. The results demonstrate that the CTFP model can capture the yielding character and also detect the minor deviations presented by different coils. The stretching factor derived from the CTFP model, as opposed to the work hardening and ductility, has a dominant effect on failure for a collection of materials with similar mechanical properties. Results also indicate that plastic deformation causes texture evolution and, consequently, an evolving yield locus. Such changes in the yield locus during deformation have an effect on stretching and friction calibration in FE simulations.

  1. A strategy for collecting ground-water data and developing a ground-water model of the Missouri River alluvial aquifer, Woodbury and Monona Counties, Iowa

    USGS Publications Warehouse

    Buchmiller, Robert C.

    1988-01-01

    A ground-water-flow model and plan for obtaining supporting data are proposed for a part of the Missouri River alluvial aquifer in Woodbury and Monona Counties, Iowa. The proposed model and the use of the principle of superposition will aid in the interpretation of the relation between ground water and surface water in the study area, particularly the effect of lowered river stages on water levels in the alluvial aquifer. Information on the geometry, hydraulic characteristics, and water levels in the alluvial aquifer needs to be collected for use in the model and for model calibration. A plan to obtain hydrologic and geologic information by use of exploratory test-well drilling is proposed. Also proposed is a monitoring network to obtain information on the spatial and temporal variability of water levels within the study area.

  2. Genetic structure and linkage disequilibrium in a diverse, representative collection of the C4 model plant, Sorghum bicolor.

    PubMed

    Wang, Yi-Hong; Upadhyaya, Hari D; Burrell, A Millie; Sahraeian, Sayed Mohammad Ebrahim; Klein, Robert R; Klein, Patricia E

    2013-05-20

    To facilitate the mapping of genes in sorghum [Sorghum bicolor (L.) Moench] underlying economically important traits, we analyzed the genetic structure and linkage disequilibrium in a sorghum mini core collection of 242 landraces with 13,390 single-nucleotide polymorphims. The single-nucleotide polymorphisms were produced using a highly multiplexed genotyping-by-sequencing methodology. Genetic structure was established using principal component, Neighbor-Joining phylogenetic, and Bayesian cluster analyses. These analyses indicated that the mini-core collection was structured along both geographic origin and sorghum race classification. Examples of the former were accessions from Southern Africa, East Asia, and Yemen. Examples of the latter were caudatums with widespread geographical distribution, durras from India, and guineas from West Africa. Race bicolor, the most primitive and the least clearly defined sorghum race, clustered among other races and formed only one clear bicolor-centric cluster. Genome-wide linkage disequilibrium analyses showed linkage disequilibrium decayed, on average, within 10-30 kb, whereas the short arm of SBI-06 contained a linkage disequilibrium block of 20.33 Mb, confirming a previous report of low recombination on this chromosome arm. Four smaller but equally significant linkage disequilibrium blocks of 3.5-35.5 kb were detected on chromosomes 1, 2, 9, and 10. We examined the genes encoded within each block to provide a first look at candidates such as homologs of GS3 and FT that may indicate a selective sweep during sorghum domestication.

  3. Genetic Structure and Linkage Disequilibrium in a Diverse, Representative Collection of the C4 Model Plant, Sorghum bicolor

    PubMed Central

    Wang, Yi-Hong; Upadhyaya, Hari D.; Burrell, A. Millie; Sahraeian, Sayed Mohammad Ebrahim; Klein, Robert R.; Klein, Patricia E.

    2013-01-01

    To facilitate the mapping of genes in sorghum [Sorghum bicolor (L.) Moench] underlying economically important traits, we analyzed the genetic structure and linkage disequilibrium in a sorghum mini core collection of 242 landraces with 13,390 single-nucleotide polymorphims. The single-nucleotide polymorphisms were produced using a highly multiplexed genotyping-by-sequencing methodology. Genetic structure was established using principal component, Neighbor-Joining phylogenetic, and Bayesian cluster analyses. These analyses indicated that the mini-core collection was structured along both geographic origin and sorghum race classification. Examples of the former were accessions from Southern Africa, East Asia, and Yemen. Examples of the latter were caudatums with widespread geographical distribution, durras from India, and guineas from West Africa. Race bicolor, the most primitive and the least clearly defined sorghum race, clustered among other races and formed only one clear bicolor-centric cluster. Genome-wide linkage disequilibrium analyses showed linkage disequilibrium decayed, on average, within 10−30 kb, whereas the short arm of SBI-06 contained a linkage disequilibrium block of 20.33 Mb, confirming a previous report of low recombination on this chromosome arm. Four smaller but equally significant linkage disequilibrium blocks of 3.5−35.5 kb were detected on chromosomes 1, 2, 9, and 10. We examined the genes encoded within each block to provide a first look at candidates such as homologs of GS3 and FT that may indicate a selective sweep during sorghum domestication. PMID:23704283

  4. NUMBERS: A collection of utilities for pre- and postprocessing two- and three-dimensional EXODUS finite element models

    SciTech Connect

    Sjaardema, G.D.

    1989-03-01

    Numbers is a shell program which reads and stores data from a finite element model described in the EXODUS database format. Within this shell program are several utility routines which generate information about the finite element model. The utilities currently implemented in Numbers allows the analyst to determine information such as the volume and coordinate limits of each of the materials in the model; the mass properties of the model; the minimum, maximum, and average element volumes for each material; the volume and change in volume of a cavity; the nodes or elements that are within a specified distance from a user-defined point, line, or plane; an estimate of the explicit central-difference timestep for each material; the validity of contact surfaces or slidelines, that is, whether two surfaces overlap at any point; and, the distance between two surfaces. 10 refs., 11 figs., 1 tab.

  5. Collecting Artifacts

    ERIC Educational Resources Information Center

    Coffey, Natalie

    2004-01-01

    Fresh out of college, the author had only a handful of items worthy of displaying, which included some fossils she had collected in her paleontology class. She had binders filled with great science information, but kids want to see "real" science, not paper science. Then it came to her: she could fill the shelves with science artifacts with the…

  6. Wastewater Collection.

    ERIC Educational Resources Information Center

    Chatterjee, Samar; And Others

    1978-01-01

    Presents a literature review of wastewater collection systems and components. This review covers: (1) planning, (2) construction; (3) sewer system evaluation; (4) maintenance; (5) rehabilitation; (6) overview prevention; and (7) wastewater pumping. A list of 111 references is also presented. (HM)

  7. Collection Security.

    ERIC Educational Resources Information Center

    Boss, Richard W.

    1984-01-01

    Presents a systematic approach to the problem of security of library collections and facilities from theft and vandalism. Highlights include responses to losses, defining security needs, typical weaknesses of facilities, policies and procedures that weaken a library's security, conducting a security audit, cost of security, cost-effectiveness, and…

  8. From the model of El Sistema in Venezuela to current applications: learning and integration through collective music education.

    PubMed

    Majno, Maria

    2012-04-01

    Over the last years, El Sistema--the Venezuelan project started in 1975 and now acknowledged worldwide as the most significant example of collective music education--has inspired a profusion of remarkable initiatives on all continents. From the original impulse by founder José Antonio Abreu, strong social principles of integration are combined with specific musical approaches to achieve individual empowerment as a large-scale alternative to endemic juvenile crime, counteracting the risk factors of social unease, serving as a stimulating example toward emancipation, and providing professional opportunities to the talented. Such a network, in turn, proves to be a powerful instrument of cultural progress: the tenets of "Sistema" become shared values able to foster development, reaching into issues of disability and rehabilitation. This paper presents continuities and contrasts in various ramifications of such a successful trend and outlines perspectives for further impact of this powerful transformational agent.

  9. Assessment of Cognitive Function in the Water Maze Task: Maximizing Data Collection and Analysis in Animal Models of Brain Injury.

    PubMed

    Whiting, Mark D; Kokiko-Cochran, Olga N

    2016-01-01

    Animal models play a critical role in understanding the biomechanical, pathophysiological, and behavioral consequences of traumatic brain injury (TBI). In preclinical studies, cognitive impairment induced by TBI is often assessed using the Morris water maze (MWM). Frequently described as a hippocampally dependent spatial navigation task, the MWM is a highly integrative behavioral task that requires intact functioning in numerous brain regions and involves an interdependent set of mnemonic and non-mnemonic processes. In this chapter, we review the special considerations involved in using the MWM in animal models of TBI, with an emphasis on maximizing the degree of information extracted from performance data. We include a theoretical framework for examining deficits in discrete stages of cognitive function and offer suggestions for how to make inferences regarding the specific nature of TBI-induced cognitive impairment. The ultimate goal is more precise modeling of the animal equivalents of the cognitive deficits seen in human TBI. PMID:27604738

  10. Collective instabilities

    SciTech Connect

    K.Y. Ng

    2003-08-25

    The lecture covers mainly Sections 2.VIII and 3.VII of the book ''Accelerator Physics'' by S.Y. Lee, plus mode-coupling instabilities and chromaticity-driven head-tail instability. Besides giving more detailed derivation of many equations, simple interpretations of many collective instabilities are included with the intention that the phenomena can be understood more easily without going into too much mathematics. The notations of Lee's book as well as the e{sup jwt} convention are followed.

  11. New data collection system for ionospheric modelling and related topics. Final report, 7 November 1988-30 September 1992

    SciTech Connect

    Sheehan, R.E.

    1993-04-15

    Work performed under this contract can be divided into three areas, (1) development and testing of a PC based Scintillation Data Recording System (SDRS) and related analysis software, (2) updating and extending D. Anderson's global ionospheric model for studies concerning the generation and transport of polar cap patches, and (3) implementation of existing and new software utilities on the PC and SUN workstation in support of Phillips Laboratory. Beginning in November 1990, SDRS has been installed at 5 field sites from Thule, Greenland to Ascension Island in the South Atlantic. Modified systems have also become TEC receiving stations for a tomography project and a remote access system designed to report scintillation activity at field sites. New software was developed to extract and display SDRS and TEC phase data on the PC. Two important additions were made to the Anderson model; the Hardy statistical model describes electron precipitation patterns, and production caused by precipitating electrons is based on a parameterized version of Strickland's flux transport model provided R. Daniel.

  12. Exploring the Relevance of the Personal and Social Responsibility Model in Adapted Physical Activity: A Collective Case Study

    ERIC Educational Resources Information Center

    Wright, Paul M.; White, Katherine; Gaebler-Spira, Deborah

    2004-01-01

    The purpose of this study was to examine the application of the Personal and Social Responsibility Model (PSRM) in an adapted physical activity program. Although the PSRM was developed for use with underserved youth, scholars in the field of adapted physical activity have noted its potential relevance for children with disabilities. Using a…

  13. Physics-Based Compact Model for CIGS and CdTe Solar Cells: From Voltage-Dependent Carrier Collection to Light-Enhanced Reverse Breakdown: Preprint

    SciTech Connect

    Sun, Xingshu; Alam, Muhammad Ashraful; Raguse, John; Garris, Rebekah; Deline, Chris; Silverman, Timothy

    2015-10-15

    In this paper, we develop a physics-based compact model for copper indium gallium diselenide (CIGS) and cadmium telluride (CdTe) heterojunction solar cells that attributes the failure of superposition to voltage-dependent carrier collection in the absorber layer, and interprets light-enhanced reverse breakdown as a consequence of tunneling-assisted Poole-Frenkel conduction. The temperature dependence of the model is validated against both simulation and experimental data for the entire range of bias conditions. The model can be used to characterize device parameters, optimize new designs, and most importantly, predict performance and reliability of solar panels including the effects of self-heating and reverse breakdown due to partial-shading degradation.

  14. Mesoscale modeling of photoelectrochemical devices: light absorption and carrier collection in monolithic, tandem, Si|WO3 microwires.

    PubMed

    Fountaine, Katherine T; Atwater, Harry A

    2014-10-20

    We analyze mesoscale light absorption and carrier collection in a tandem junction photoelectrochemical device using electromagnetic simulations. The tandem device consists of silicon (E(g,Si) = 1.1 eV) and tungsten oxide (E(g,WO3) = 2.6 eV) as photocathode and photoanode materials, respectively. Specifically, we investigated Si microwires with lengths of 100 µm, and diameters of 2 µm, with a 7 µm pitch, covered vertically with 50 µm of WO3 with a thickness of 1 µm. Many geometrical variants of this prototypical tandem device were explored. For conditions of illumination with the AM 1.5G spectra, the nominal design resulted in a short circuit current density, J(SC), of 1 mA/cm(2), which is limited by the WO3 absorption. Geometrical optimization of photoanode and photocathode shape and contact material selection, enabled a three-fold increase in short circuit current density relative to the initial design via enhanced WO3 light absorption. These findings validate the usefulness of a mesoscale analysis for ascertaining optimum optoelectronic performance in photoelectrochemical devices.

  15. Estimation of PM10 concentrations over Seoul using multiple empirical models with AERONET and MODIS data collected during the DRAGON-Asia campaign

    NASA Astrophysics Data System (ADS)

    Seo, S.; Kim, J.; Lee, H.; Jeong, U.; Kim, W.; Holben, B. N.; Kim, S.-W.; Song, C. H.; Lim, J. H.

    2015-01-01

    The performance of various empirical linear models to estimate the concentrations of surface-level particulate matter with a diameter less than 10 μm (PM10) was evaluated using Aerosol Robotic Network (AERONET) sun photometer and Moderate-Resolution Imaging Spectroradiometer (MODIS) data collected in Seoul during the Distributed Regional Aerosol Gridded Observation Network (DRAGON)-Asia campaign from March to May 2012. An observed relationship between the PM10 concentration and the aerosol optical depth (AOD) was accounted for by several parameters in the empirical models, including boundary layer height (BLH), relative humidity (RH), and effective radius of the aerosol size distribution (Reff), which was used here for the first time in empirical modeling. Among various empirical models, the model which incorporates both BLH and Reff showed the highest correlation, which indicates the strong influence of BLH and Reff on the PM10 estimations. Meanwhile, the effect of RH on the relationship between AOD and PM10 appeared to be negligible during the campaign period (spring), when RH is generally low in northeast Asia. A large spatial dependency of the empirical model performance was found by categorizing the locations of the collected data into three different site types, which varied in terms of the distances between instruments and source locations. When both AERONET and MODIS data sets were used in the PM10 estimation, the highest correlations between measured and estimated values (R = 0.76 and 0.76 using AERONET and MODIS data, respectively) were found for the residential area (RA) site type, while the poorest correlations (R = 0.61 and 0.68 using AERONET and MODIS data, respectively) were found for the near-source (NS) site type. Significant seasonal variations of empirical model performances for PM10 estimation were found using the data collected at Yonsei University (one of the DRAGON campaign sites) over a period of 17 months including the DRAGON campaign

  16. Insights from socio-hydrology modelling on dealing with flood risk: roles of collective memory, risk-taking attitude and trust (Invited)

    NASA Astrophysics Data System (ADS)

    Viglione, A.; Di Baldassarre, G.; Brandimarte, L.; Kuil, L.; Carr, G.; Salinas, J.; Scolobig, A.

    2013-12-01

    The risk coping culture of a community plays a major role in decision making in urban flood plains. While flood awareness is not necessarily linked to being prepared to face flooding at an individual level, the connection at the community level seems to be stronger through creating policy and initiating protection works. In this work we analyse, in a conceptual way, the interplay of community risk coping culture, flooding damage and economic growth. We particularly focus on three aspects: (i) collective memory, i.e., the capacity of the community to keep the awareness of flooding high; (ii) risk-taking attitude, i.e., the amount of risk a community is collectively willing to expose themselves to; and (iii) trust of people in risk protection measures. We use a dynamic model that represents the feedbacks between the hydrological and social system components. The model results indicate that, on one hand, by under perceiving the risk of flooding (because of short collective memory and too much trust in flood protection structures) in combination with a high risk-attitude, community survival is severely limited because of destruction caused by flooding. On the other hand, high perceived risk (long memory and lack of trust in flood protection structures) relative to the actual risk leads to lost economic opportunities and recession. There are many optimal scenarios for survival and economic growth, but greater certainty of survival plus economic growth can be achieved by ensuring community has accurate risk perception (memory neither too long nor too short and trust in flood protection neither too great nor too low) combined with a low to moderate risk-taking attitude. Interestingly, the model gives rise to situations in which the development of the community in the floodplain is path dependent, i.e., the history of flooding may lead to its growth or recession. Schematic of human adjustments to flooding: (a) settling away from the river; (b) raising levees/dikes.

  17. Neutron-Rich {sup 62,64,64}Fe Show Enhanced Collectivity: The Washout of N = 40 in Terms of Experiment, Valence Proton Symmetry and Shell Model

    SciTech Connect

    Rother, W.; Dewald, A.; Fransen, C.; Hackstein, M.; Jolie, J.; Pissulla, Th.; Zel, K.-O.; Iwasaki, H.; Baugher, T.; Brown, B. A.; Gade, A.; Glasmacher, T.; McDaniel, S.; Ratkiewicz, A.; Voss, P.; Walsh, K. A.; Lenzi, S. M.; Ur, C. A.; Starosta, K.; Bazin, D.

    2011-10-28

    Probing shell structure at a large neutron excess has been of particular interest in recent times. Neutron-rich nuclei between the proton shell closures Z = 20 and Z = 28 offer an exotic testing ground for shell evolution. The development of the N = 40gap between neutron fp and lg{sub 9/2} shells gives rise to highly interesting variations of collectivity for nuclei in this region. While {sup 68}Ni shows doubly magic properties in level energies and transition strengths, this was not observed in neighbouring nuclei. Especially neutron-rich Fe isotopes proved particularly resistant to calculational approaches using the canonical valence space (fpg) resulting in important deviations of the predicted collectivity. Only an inclusion of the d{sub 5/2}-orbital could solve the problem [1]. Hitherto no transition strengths for {sup 66}Fe have been reported. We determined B(E2,2{sup +}{sub 1}{yields}0{sup +}{sub 1}) values from lifetimes measured with the recoil distance Doppler-shift method using the Cologne plunger for radioactive beams at National Superconducting Cyclotron Laboratory at Michigan State University. Excited states were populated by projectile Coulomb excitation for {sup 62,64,66}Fe. The data show a rise in collectivity for Fe isotopes towards N = 40. Results [2] are interpreted by means of a modified version of the Valence Proton Symmetry [3] and compared to shell model calculations using a new effective interaction recently developed for the fpgd valence space [4].

  18. Modeling and analysis of reservation frame slotted-ALOHA in wireless machine-to-machine area networks for data collection.

    PubMed

    Vázquez-Gallego, Francisco; Alonso, Luis; Alonso-Zarate, Jesus

    2015-02-09

    Reservation frame slotted-ALOHA (RFSA) was proposed in the past to manage the access to the wireless channel when devices generate long messages fragmented into small packets. In this paper, we consider an M2M area network composed of end-devices that periodically respond to the requests from a gateway with the transmission of fragmented messages. The idle network is suddenly set into saturation, having all end-devices attempting to get access to the channel simultaneously. This has been referred to as delta traffic. While previous works analyze the throughput of RFSA in steady-state conditions, assuming that traffic is generated following random distributions, the performance of RFSA under delta traffic has never received attention. In this paper, we propose a theoretical model to calculate the average delay and energy consumption required to resolve the contention under delta traffic using RFSA.We have carried out computer-based simulations to validate the accuracy of the theoretical model and to compare the performance for RFSA and FSA. Results show that there is an optimal frame length that minimizes delay and energy consumption and which depends on the number of end-devices. In addition, it is shown that RFSA reduces the energy consumed per end-device by more than 50% with respect to FSA under delta traffic.

  19. Model Evaluation of Aerosol Wet Scavenging in Deep Convective Clouds Based on Observations Collected during the DC3 Campaign

    NASA Astrophysics Data System (ADS)

    Yang, Q.; Easter, R. C.; Fast, J. D.; Wang, H.; Ghan, S. J.; Campuzano Jost, P.; Barth, M. C.; Fan, J.; Morrison, H.; Jimenez, J. L.; Bela, M. M.; Markovic, M. Z.

    2014-12-01

    Deep convective storms greatly influence the vertical distribution of aerosols by transporting aerosols from the boundary layer to the upper troposphere and by removing aerosols through wet scavenging processes. Model representation of wet scavenging is a major uncertainty in simulating the vertical distribution of aerosols due partly to limited constraints by observations. The effect of wet scavenging on ambient aerosols in deep mid-latitude continental convective clouds is studied for a severe storm case in the vicinity of the ARM Southern Great Plains site on May 29, 2012 during the Deep Convective Clouds and Chemistry Project (DC3) field campaign. A new budget analysis approach is developed to characterize the convective transport to the upper troposphere based on the vertical distribution of several slowly reacting and nearly insoluble trace gases (i.e., CO, acetone, and benzene). A similar budget framework is applied to aerosols combined with the known transport efficiency to estimate wet-scavenging efficiency. The chemistry version of the Weather Research and Forecasting model (WRF-Chem) simulates the storm initiation timing and structure reasonably well when compared against radar observations from the NSSL national 3-D reflectivity Mosaic data. Simulated vertical profiles of humidity and temperature also closely agree with radiosonde measurements before and during the storm. High scavenging efficiencies (~80%) for aerosol number (Dp < 2.5μm) and mass (Dp < 1μm) are obtained from the observations. Both observation analyses and the simulation show that, between the two dominant aerosol species, organic aerosol shows a slightly higher scavenging efficiency than sulfate aerosol, and higher scavenging efficiency is found for larger particle sizes (0.15 - 2.5μm versus 0.03 - 0.15μm). However, the model underestimates the wet scavenging efficiency (by up to 50%), in general, for both mass and number concentrations. The effect of neglecting secondary

  20. Independence and interdependence in collective decision making: an agent-based model of nest-site choice by honeybee swarms.

    PubMed

    List, Christian; Elsholtz, Christian; Seeley, Thomas D

    2009-03-27

    Condorcet's jury theorem shows that when the members of a group have noisy but independent information about what is best for the group as a whole, majority decisions tend to outperform dictatorial ones. When voting is supplemented by communication, however, the resulting interdependencies between decision makers can strengthen or undermine this effect: they can facilitate information pooling, but also amplify errors. We consider an intriguing non-human case of independent information pooling combined with communication: the case of nest-site choice by honeybee (Apis mellifera) swarms. It is empirically well documented that when there are different nest sites that vary in quality, the bees usually choose the best one. We develop a new agent-based model of the bees' decision process and show that its remarkable reliability stems from a particular interplay of independence and interdependence between the bees.

  1. A collection of the collapsed results of general tank tests of miscellaneous flying-boat-hull models

    NASA Technical Reports Server (NTRS)

    Locke, F W S , Jr

    1947-01-01

    Presented here are the summary charts of the collapsed results of general tank tests of about 100 flying boat hull models. These summary charts are intended to be used as an engineering tool to enable a flying boat designer to grasp more quickly the significance of various hull form parameters as they influence his particular airplane. The form in which the charts are prepared is discussed in some detail in order to make them clearer to the designer. This is a data report, and no attempt has been made to produce conclusions or correlations of the usual sort. However, some generalizations are put forward on the various methods in which summary charts may be used.

  2. Quantitative structure-activity relationship models for predicting drug-induced liver injury based on FDA-approved drug labeling annotation and using a large collection of drugs.

    PubMed

    Chen, Minjun; Hong, Huixiao; Fang, Hong; Kelly, Reagan; Zhou, Guangxu; Borlak, Jürgen; Tong, Weida

    2013-11-01

    Drug-induced liver injury (DILI) is one of the leading causes of the termination of drug development programs. Consequently, identifying the risk of DILI in humans for drug candidates during the early stages of the development process would greatly reduce the drug attrition rate in the pharmaceutical industry but would require the implementation of new research and development strategies. In this regard, several in silico models have been proposed as alternative means in prioritizing drug candidates. Because the accuracy and utility of a predictive model rests largely on how to annotate the potential of a drug to cause DILI in a reliable and consistent way, the Food and Drug Administration-approved drug labeling was given prominence. Out of 387 drugs annotated, 197 drugs were used to develop a quantitative structure-activity relationship (QSAR) model and the model was subsequently challenged by the left of drugs serving as an external validation set with an overall prediction accuracy of 68.9%. The performance of the model was further assessed by the use of 2 additional independent validation sets, and the 3 validation data sets have a total of 483 unique drugs. We observed that the QSAR model's performance varied for drugs with different therapeutic uses; however, it achieved a better estimated accuracy (73.6%) as well as negative predictive value (77.0%) when focusing only on these therapeutic categories with high prediction confidence. Thus, the model's applicability domain was defined. Taken collectively, the developed QSAR model has the potential utility to prioritize compound's risk for DILI in humans, particularly for the high-confidence therapeutic subgroups like analgesics, antibacterial agents, and antihistamines.

  3. Strategy for NMR metabolomic analysis of urine in mouse models of obesity--from sample collection to interpretation of acquired data.

    PubMed

    Pelantová, Helena; Bugáňová, Martina; Anýž, Jiří; Železná, Blanka; Maletínská, Lenka; Novák, Daniel; Haluzík, Martin; Kuzma, Marek

    2015-11-10

    The mouse model of monosodium glutamate induced obesity was used to examine and consequently optimize the strategy for analysis of urine samples by NMR spectroscopy. A set of nineteen easily detectable metabolites typical in obesity-related studies was selected. The impact of urine collection protocol, choice of (1)H NMR pulse sequence, and finally the impact of the normalization method on the detected concentration of selected metabolites were investigated. We demonstrated the crucial effect of food intake and diurnal rhythms resulting in the choice of a 24-hour fasting collection protocol as the most convenient for tracking obesity-induced increased sensitivity to fasting. It was shown that the Carr-Purcell-Meiboom-Gill (CPMG) experiment is a better alternative to one-dimensional nuclear Overhauser enhancement spectroscopy (1D-NOESY) for NMR analysis of mouse urine due to its ability to filter undesirable signals of proteins naturally present in rodent urine. Normalization to total spectral area provided comparable outcomes as did normalization to creatinine or probabilistic quotient normalization in the CPMG-based model. The optimized approach was found to be beneficial mainly for low abundant metabolites rarely monitored due to their overlap by strong protein signals. PMID:26263053

  4. Mathematical modeling of microbially induced crown corrosion in wastewater collection systems and laboratory investigation and modeling of sulfuric acid corrosion of concrete

    NASA Astrophysics Data System (ADS)

    Jahani, Fereidoun

    In the model for microbially induced crown corrosion, the diffusion of sulfide inside the concrete pores, its biological conversion to sulfuric acid, and the corrosion of calcium carbonate aggregates are represented. The corrosion front is modeled as a moving boundary. The location of the interface between the corrosion layer and the concrete is determined as part of the solution to the model equations. This model consisted of a system of one dimensional reaction-diffusion equations coupled to an equation describing the movement of the corrosion front. The equations were solved numerically using finite element Galerkin approximation. The concentration profiles of sulfide in the air and the liquid phases, the pH as a function of concrete depth, and the position of the corrosion front. A new equation for the corrosion rate was also derived. A more specific model for the degradation of a concrete specimen exposed to a sulfuric acid solution was also studied. In this model, diffusion of hydrogen ions and their reaction with alkaline components of concrete were expressed using Fick's Law of diffusion. The model equations described the moving boundary, the dissolution rate of alkaline components in the concrete, volume increase of sulfuric acid solution over the concrete specimen, and the boundary conditions on the surface of the concrete. An apparatus was designed and experiments were performed to measure pH changes on the surface of concrete. The data were used to calculate the dissolution rate of the concrete and, with the model, to determine the diffusion rate of sulfuric acid in the corrosion layer and corrosion layer thickness. Electrochemical Impedance Spectroscopy (EIS) was used to study the corrosion rate of iron pins embedded in the concrete sample. The open circuit potential (OCP) determined the onset of corrosion on the surface of the pins. Visual observation of the corrosion layer thickness was in good agreement with the simulation results.

  5. Acoustic mode measurements in the inlet of a model turbofan using a continuously rotating rake - Data collection/analysis techniques

    NASA Technical Reports Server (NTRS)

    Hall, David G.; Heidelberg, Laurence; Konno, Kevin

    1993-01-01

    The rotating microphone measurement technique and data analysis procedures are documented which are used to determine circumferential and radial acoustic mode content in the inlet of the Advanced Ducted Propeller (ADP) model. Circumferential acoustic mode levels were measured at a series of radial locations using the Doppler frequency shift produced by a rotating inlet microphone probe. Radial mode content was then computed using a least squares curve fit with the measured radial distribution for each circumferential mode. The rotating microphone technique is superior to fixed-probe techniques because it results in minimal interference with the acoustic modes generated by rotor-stator interaction. This effort represents the first experimental implementation of a measuring technique developed by T. G. Sofrin. Testing was performed in the NASA Lewis Low Speed Anechoic Wind Tunnel at a simulated takeoff condition of Mach 0.2. The design is included of the data analysis software and the performance of the rotating rake apparatus. The effect of experiment errors is also discussed.

  6. Acoustic mode measurements in the inlet of a model turbofan using a continuously rotating rake: Data collection/analysis techniques

    NASA Technical Reports Server (NTRS)

    Hall, David G.; Heidelberg, Laurence; Konno, Kevin

    1993-01-01

    The rotating microphone measurement technique and data analysis procedures are documented which are used to determine circumferential and radial acoustic mode content in the inlet of the Advanced Ducted Propeller (ADP) model. Circumferential acoustic mode levels were measured at a series of radial locations using the Doppler frequency shift produced by a rotating inlet microphone probe. Radial mode content was then computed using a least squares curve fit with the measured radial distribution for each circumferential mode. The rotating microphone technique is superior to fixed-probe techniques because it results in minimal interference with the acoustic modes generated by rotor-stator interaction. This effort represents the first experimental implementation of a measuring technique developed by T. G. Sofrin. Testing was performed in the NASA Lewis Low Speed Anechoic Wind Tunnel at a simulated takeoff condition of Mach 0.2. The design is included of the data analysis software and the performance of the rotating rake apparatus. The effect of experiment errors is also discussed.

  7. Collective magnetic properties of cobalt nanocrystals self-assembled in a hexagonal network: Theoretical model supported by experiments

    NASA Astrophysics Data System (ADS)

    Russier, V.; Petit, C.; Legrand, J.; Pileni, M. P.

    2000-08-01

    Numerical calculations of magnetization curves versus applied field based on a simple model taking into account dipolar interactions were performed for cobalt nanocrystals deposited on a substrate and organized in a hexagonal network. A random distribution of the easy axes orientations of the nanocrystals is considered. The study is focused on the effect of the applied field orientation relative to the substrate surface. Two orientations were chosen: parallel and perpendicular to the surface. The corresponding hysteresis loops are compared to that of a volumic random distribution of nanocrystals at vanishing concentration. The calculation results are compared to experimental data for spherical cobalt nanocrystals coated by lauric acid (C12H25COO-). The particles are either dispersed in hexane (considered as randomly distributed) or deposited in a hexagonal network on a highly oriented pyrolithic graphite substrate. The changes in the magnetization curves with the applied field orientation on the one hand and when going from dispersed to deposited particles on the other hand were calculated and measured. Qualitative agreement is obtained.

  8. Boltzmann equation modelling of Learning Dynamics. Comment on "Collective learning modeling based on the kinetic theory of active particles" by D. Burini et al.

    NASA Astrophysics Data System (ADS)

    Shizgal, Bernie

    2016-03-01

    The paper by Burini et al. [7] presents an interesting use of the Boltzmann equation of kinetic theory to model real learning processes. The authors provide a comprehensive discussion of the basic concepts involved in their modelling work. The Boltzmann equation as used by physicists and chemists to model a variety of transport processes in many diverse fields is based on the notion of the binary collisions between identifiable particles in the defined system [9]. The particles exchange energy on collision and the distribution function, which depends on the three velocity components and the three spatial coordinates, varies with time. The classical or quantum collision dynamics between particles play a central role in the definition of the kernels in the integral operators that define the Boltzmann equation [8].

  9. Collective Quartics from Simple Groups

    SciTech Connect

    Hook, Anson; Wacker, Jay G.; /SLAC

    2010-08-26

    This article classifies Little Higgs models that have collective quartic couplings. There are two classes of collective quartics: Special Cosets and Special Quartics. After taking into account dangerous singlets, the smallest Special Coset models are SU(5)/SO(5) and SU(6)/Sp(6). The smallest Special Quartic model is SU(5)/SU(3) x SU(2) x U(1) and has not previously been considered as a candidate Little Higgs model.

  10. Forward problem solution as the operator of filtered and back projection matrix to reconstruct the various method of data collection and the object element model in electrical impedance tomography

    SciTech Connect

    Ain, Khusnul; Kurniadi, Deddy; Suprijanto; Santoso, Oerip; Wibowo, Arif

    2015-04-16

    Back projection reconstruction has been implemented to get the dynamical image in electrical impedance tomography. However the implementation is still limited in method of adjacent data collection and circular object element model. The study aims to develop the methods of back projection as reconstruction method that has the high speed, accuracy, and flexibility, which can be used for various methods of data collection and model of the object element. The proposed method uses the forward problem solution as the operator of filtered and back projection matrix. This is done through a simulation study on several methods of data collection and various models of the object element. The results indicate that the developed method is capable of producing images, fastly and accurately for reconstruction of the various methods of data collection and models of the object element.

  11. The physics of a single-event upset in integrated circuits: A review and critique of analytical models for charge collection

    NASA Technical Reports Server (NTRS)

    Vonroos, O.; Zoutendyk, J.

    1983-01-01

    When an energetic particle (kinetic energy 0.5 MeV) originating from a radioactive decay or a cosmic ray transverse the active regions of semiconductor devices used in integrated circuit (IC) chips, it leaves along its track a high density electron hole plasma. The subsequent decay of this plasma by drift and diffusion leads to charge collection at the electrodes large enough in most cases to engender a false reading, hence the name single-event upset (SEU). The problem of SEU's is particularly severe within the harsh environment of Jupiter's radiation belts and constitutes therefore a matter of concern for the Galileo mission. The physics of an SEU event is analyzed in some detail. Owing to the predominance of nonlinear space charge effects and the fact that positive (holes) and negative (electrons) charges must be treated on an equal footing, analytical models for the ionized-charge collection and their corresponding currents as a function of time prove to be inadequate even in the simplest case of uniformly doped, abrupt p-n junctions in a one-dimensional geometry. The necessity for full-fledged computer simulation of the pertinent equations governing the electron-hole plasma therefore becomes imperative.

  12. Final Report for "Improved Representations of Cloud Microphysics for Model and Remote Sensing Evaluation using Data Collected during ISDAC, TWP-ICE and RACORO

    SciTech Connect

    McFarquhar, Greg M.

    2003-06-11

    We were funded by ASR to use data collected during ISDAC and TWP-ICE to evaluate models with a variety of temporal and spatial scales, to evaluate ground-based remote sensing retrievals and to develop cloud parameterizations with the end goal of improving the modeling of cloud processes and properties and their impact on atmospheric radiation. In particular, we proposed to: 1) Calculate distributions of microphysical properties observed in arctic stratus during ISDAC for initializing and evaluating LES and GCMs, and for developing parameterizations of effective particle sizes, mean fall velocities, and mean single-scattering properties for such models; 2) Improve representations of particle sizes, fall velocities and scattering properties for tropical and arctic cirrus using TWP-ICE, ISDAC and M-PACE data, and to determine the contributions that small ice crystals, with maximum dimensions D less than 50 μm, make to mass and radiative properties; 3) Study fundamental interactions between clouds and radiation by improving representations of small quasi-spherical particles and their scattering properties. We were additionally funded 1-year by ASR to use RACORO data to develop an integrated product of cloud microphysical properties. We accomplished all of our goals.

  13. Improvements in Representations of Cloud Microphysics for BBHRP and Models using Data Collected during M-PACE and TWP-ICE

    SciTech Connect

    Greg M. McFarquhar

    2010-02-22

    In our research we proposed to use data collected during the 2004 Mixed-Phase Arctic Cloud Experiment (MPACE) and the 2006 Tropical Warm Pool International Cloud Experiment (TWP-ICE) to improve retrievals of ice and mixed-phase clouds, to improve our understanding of how cloud and radiative processes affect cloud life cycles, and to develop and test methods for using ARM data more effectively in model. In particular, we proposed to: 1) use MPACE in-situ data to determine how liquid water fraction and cloud ice and liquid effective radius (r{sub ei} and r{sub ew}) vary with temperature, normalized cloud altitude and other variables for Arctic mixed-phase clouds, and to use these data to evaluate the performance of model parameterization schemes and remote sensing retrieval algorithms; 2) calculate rei and size/shape distributions using TWP-ICE in-situ data, investigate their dependence on cirrus type (oceanic or continental anvils or cirrus not directly traced to convection), and develop and test representations for MICROBASE; 3) conduct fundamental research enhancing our understanding of cloud/radiative interactions, concentrating on effects of small crystals and particle shapes and sizes on radiation; and 4) improve representations of microphysical processes for models (fall-out, effective density, mean scattering properties, rei and rew) and provide them to ARM PIs. In the course of our research, we made substantial progress on all four goals.

  14. The Collective Impact Model and Its Potential for Health Promotion: Overview and Case Study of a Healthy Retail Initiative in San Francisco.

    PubMed

    Flood, Johnna; Minkler, Meredith; Hennessey Lavery, Susana; Estrada, Jessica; Falbe, Jennifer

    2015-10-01

    As resources for health promotion become more constricted, it is increasingly important to collaborate across sectors, including the private sector. Although many excellent models for cross-sector collaboration have shown promise in the health field, collective impact (CI), an emerging model for creating larger scale change, has yet to receive much study. Complementing earlier collaboration approaches, CI has five core tenets: a shared agenda, shared measurement systems, mutually reinforcing activities, continuous communication, and a central infrastructure. In this article, we describe the CI model and its key dimensions and constructs. We briefly compare CI to community coalition action theory and discuss our use of the latter to provide needed detail as we apply CI in a critical case study analysis of the Tenderloin Healthy Corner Store Coalition in San Francisco, California. Using Yin's multimethod approach, we illustrate how CI strategies, augmented by the community coalition action theory, are being used, and with what successes or challenges, to help affect community- and policy-level change to reduce tobacco and alcohol advertising and sales, while improving healthy, affordable, and sustainable food access. We discuss the strengths and weaknesses of CI as a framework for health promotion, as well as the benefits, challenges, and initial outcomes of the healthy retail project and its opportunities for scale-up. Implications for health promotion practice and research also are discussed. PMID:25810470

  15. The Collective Impact Model and Its Potential for Health Promotion: Overview and Case Study of a Healthy Retail Initiative in San Francisco.

    PubMed

    Flood, Johnna; Minkler, Meredith; Hennessey Lavery, Susana; Estrada, Jessica; Falbe, Jennifer

    2015-10-01

    As resources for health promotion become more constricted, it is increasingly important to collaborate across sectors, including the private sector. Although many excellent models for cross-sector collaboration have shown promise in the health field, collective impact (CI), an emerging model for creating larger scale change, has yet to receive much study. Complementing earlier collaboration approaches, CI has five core tenets: a shared agenda, shared measurement systems, mutually reinforcing activities, continuous communication, and a central infrastructure. In this article, we describe the CI model and its key dimensions and constructs. We briefly compare CI to community coalition action theory and discuss our use of the latter to provide needed detail as we apply CI in a critical case study analysis of the Tenderloin Healthy Corner Store Coalition in San Francisco, California. Using Yin's multimethod approach, we illustrate how CI strategies, augmented by the community coalition action theory, are being used, and with what successes or challenges, to help affect community- and policy-level change to reduce tobacco and alcohol advertising and sales, while improving healthy, affordable, and sustainable food access. We discuss the strengths and weaknesses of CI as a framework for health promotion, as well as the benefits, challenges, and initial outcomes of the healthy retail project and its opportunities for scale-up. Implications for health promotion practice and research also are discussed.

  16. A New Model for the Seismogenic Behavior of Subducted Seamounts Based on Multi-Channel Seismic Reflection and GPS Data Collected in Central Ecuador.

    NASA Astrophysics Data System (ADS)

    Collot, J. Y.; Sanclemente, E.; Ribodetti, A.; Chlieh, M.; Jarrin, P.; Nocquet, J. M.

    2014-12-01

    The relationship between subducted seamounts and earthquakes has remained controversial. Although seamounts are expected to subduct aseismically, they have also been considered to generate large earthquakes. Based on a remarkable case study in Central Ecuador, we show that a subducted seamount can lock the shallow megathrust along its trailing flank preparing for a possible shallow (<20 km), large magnitude (Mw ~7.0) tsunamogenic earthquake, while its leading flank keeps partially creeping along with frequent earthquake swarms and slow slip events (SSE). The erosive Ecuador convergent margin, which basement consists of high velocity (Vp=5 km/s) mafic rocks, is underthrust eastward at 4.7 cm/yr by the rugged Carnegie Ridge. As modeled by global positioning system (GPS) measurements acquired as close as 35 km from the trench axis at La Plata Island, the Central Ecuador margin figures a creeping subduction segment with the exception of a 50 km-diameter locked patch centered over the uplifted La Plata Island region. The 3D geometry of the plate-interface megathrust obtained from 2D-PreStack-Depth-Migration of a grid of multi-channel seismic reflection data collected near La Plata Island reveals a collection of closely spaced peaks that belong to a broad (55 X ~50 km) low-drag shape subducted seamount. The clear spatial correlation between the seamount and the highly coupled zone denotes the seamount as the main cause for both the locked patch and the island uplift. The absence of a seismically imaged subduction channel, the highly jagged seamount-trailing flank and the stiffness of the oceanic margin are found to be the principal long-term characteristics associated with shallow locking of the megathrust. Moreover, the combination of our structural interpretation and inter-seismic coupling map with 14-years of relocated seismicity, and the 2010 SSE and its associated microseismicity allow to propose a new model for the seismogenic behavior of subducting seamounts.

  17. Increased Na+/H+ exchanger activity on the apical surface of a cilium-deficient cortical collecting duct principal cell model of polycystic kidney disease

    PubMed Central

    Olteanu, Dragos; Liu, Xiaofen; Liu, Wen; Roper, Venus C.; Sharma, Neeraj; Yoder, Bradley K.; Satlin, Lisa M.; Schwiebert, Erik M.

    2012-01-01

    Pathophysiological anomalies in autosomal dominant and recessive forms of polycystic kidney disease (PKD) may derive from impaired function/formation of the apical central monocilium of ductal epithelia such as that seen in the Oak Ridge polycystic kidney or orpk (Ift88Tg737Rpw) mouse and its immortalized cell models for the renal collecting duct. According to a previous study, Na/H exchanger (NHE) activity may contribute to hyperabsorptive Na+ movement in cilium-deficient (“mutant”) cortical collecting duct principal cell monolayers derived from the orpk mice compared with cilium-competent (“rescued”) monolayers. To examine NHE activity, we measured intracellular pH (pHi) by fluorescence imaging with the pH-sensitive dye BCECF, and used a custom-designed perfusion chamber to control the apical and basolateral solutions independently. Both mutant and rescued monolayers exhibited basolateral Na+-dependent acid-base transporter activity in the nominal absence of CO2/HCO3−. However, only the mutant cells displayed appreciable apical Na+-induced pHi recoveries from NH4+ prepulse-induced acid loads. Similar results were obtained with isolated, perfused collecting ducts from orpk vs. wild-type mice. The pHi dependence of basolateral cariporide/HOE-694-sensitive NHE activity under our experimental conditions was similar in both mutant and rescued cells, and 3.5- to 4.5-fold greater than apical HOE-sensitive NHE activity in the mutant cells (pHi 6.23–6.68). Increased apical NHE activity correlated with increased apical NHE1 expression in the mutant cells, and increased apical localization in collecting ducts of kidney sections from orpk vs. control mice. A kidney-specific conditional cilium-knockout mouse produced a more acidic urine compared with wild-type littermates and became alkalotic by 28 days of age. This study provides the first description of altered NHE activity, and an associated acid-base anomaly in any form of PKD. PMID:22301060

  18. 2015 Cataloging Hidden Special Collections and Archives Unconference and Symposium: Innovation, Collaboration, and Models. Proceedings of the CLIR Cataloging Hidden Special Collections and Archives Symposium (Philadelphia, Pennsylvania, March 12-13, 2015)

    ERIC Educational Resources Information Center

    Oestreicher, Cheryl, Ed.

    2015-01-01

    The 2015 CLIR Unconference & Symposium was the capstone event to seven years of grant funding through CLIR's Cataloging Hidden Special Collections and Archives program. These proceedings group presentations by theme. Collaborations provides examples of multi-institutional projects, including one international collaboration; Student and Faculty…

  19. Who Takes Precautionary Action in the Face of the New H1N1 Influenza? Prediction of Who Collects a Free Hand Sanitizer Using a Health Behavior Model

    PubMed Central

    Reuter, Tabea; Renner, Britta

    2011-01-01

    Background In order to fight the spread of the novel H1N1 influenza, health authorities worldwide called for a change in hygiene behavior. Within a longitudinal study, we examined who collected a free bottle of hand sanitizer towards the end of the first swine flu pandemic wave in December 2009. Methods 629 participants took part in a longitudinal study assessing perceived likelihood and severity of an H1N1 infection, and H1N1 influenza related negative affect (i.e., feelings of threat, concern, and worry) at T1 (October 2009, week 43–44) and T2 (December 2009, week 51–52). Importantly, all participants received a voucher for a bottle of hand sanitizer at T2 which could be redeemed in a university office newly established for this occasion at T3 (ranging between 1–4 days after T2). Results Both a sequential longitudinal model (M2) as well as a change score model (M3) showed that greater perceived likelihood and severity at T1 (M2) or changes in perceived likelihood and severity between T1 and T2 (M3) did not directly drive protective behavior (T3), but showed a significant indirect impact on behavior through H1N1 influenza related negative affect. Specifically, increases in perceived likelihood (β = .12), severity (β = .24) and their interaction (β = .13) were associated with a more pronounced change in negative affect (M3). The more threatened, concerned and worried people felt (T2), the more likely they were to redeem the voucher at T3 (OR = 1.20). Conclusions Affective components need to be considered in health behavior models. Perceived likelihood and severity of an influenza infection represent necessary but not sufficient self-referential knowledge for paving the way for preventive behaviors. PMID:21789224

  20. Reduction of collectivity at very high spins in 134Nd: Expanding the projected-shell-model basis up to 10-quasiparticle states

    NASA Astrophysics Data System (ADS)

    Wang, Long-Jun; Sun, Yang; Mizusaki, Takahiro; Oi, Makito; Ghorui, Surja K.

    2016-03-01

    Background: The recently started physics campaign with the new generation of γ -ray spectrometers, "GRETINA" and "AGATA," will possibly produce many high-quality γ rays from very fast-rotating nuclei. Microscopic models are needed to understand these states. Purpose: It is a theoretical challenge to describe high-spin states in a shell-model framework by the concept of configuration mixing. To meet the current needs, one should overcome the present limitations and vigorously extend the quasiparticle (qp) basis of the projected shell model (PSM). Method: With the help of the recently proposed Pfaffian formulas, we apply the new algorithm and develop a new PSM code that extends the configuration space to include up to 10-qp states. The much-enlarged multi-qp space enables us to investigate the evolutional properties at very high spins in fast-rotating nuclei. Results: We take 134Nd as an example to demonstrate that the known experimental yrast and the several negative-parity side bands in this nucleus could be well described by the calculation. The variations in moment of inertia with spin are reproduced and explained in terms of successive band crossings among the 2-qp, 4-qp, 6-qp, 8-qp, and 10-qp states. Moreover, the electric quadrupole transitions in these bands are studied. Conclusions: A pronounced decrease in the high-spin B (E 2 ) of 134Nd is predicted, which suggests reduction of collectivity at very high spins because of increased level density and complex band mixing. The possibility for a potential application of the present development in the study of highly excited states in warm nuclei is mentioned.

  1. Multi-scale analysis of collective behavior in 2D self-propelled particle models of swarms: An Advection-Diffusion with Memory Approach

    NASA Astrophysics Data System (ADS)

    Raghib, Michael; Levin, Simon; Kevrekidis, Ioannis

    2010-05-01

    Self-propelled particle models (SPP's) are a class of agent-based simulations that have been successfully used to explore questions related to various flavors of collective motion, including flocking, swarming, and milling. These models typically consist of particle configurations, where each particle moves with constant speed, but changes its orientation in response to local averages of the positions and orientations of its neighbors found within some interaction region. These local averages are based on `social interactions', which include avoidance of collisions, attraction, and polarization, that are designed to generate configurations that move as a single object. Errors made by the individuals in the estimates of the state of the local configuration are modeled as a random rotation of the updated orientation resulting from the social rules. More recently, SPP's have been introduced in the context of collective decision-making, where the main innovation consists of dividing the population into naïve and `informed' individuals. Whereas naïve individuals follow the classical collective motion rules, members of the informed sub-population update their orientations according to a weighted average of the social rules and a fixed `preferred' direction, shared by all the informed individuals. Collective decision-making is then understood in terms of the ability of the informed sub-population to steer the whole group along the preferred direction. Summary statistics of collective decision-making are defined in terms of the stochastic properties of the random walk followed by the centroid of the configuration as the particles move about, in particular the scaling behavior of the mean squared displacement (msd). For the region of parameters where the group remains coherent , we note that there are two characteristic time scales, first there is an anomalous transient shared by both purely naïve and informed configurations, i.e. the scaling exponent lies between 1 and

  2. Program Management Collection. "LINCS" Resource Collection News

    ERIC Educational Resources Information Center

    Literacy Information and Communication System, 2011

    2011-01-01

    This edition of "'LINCS' Resource Collection News" features the Program Management Collection, which covers the topics of Assessment, Learning Disabilities, and Program Improvement. Each month Collections News features one of the three "LINCS" (Literacy Information and Communication System) Resource Collections--Basic Skills, Program Management,…

  3. Workforce Competitiveness Collection. "LINCS" Resource Collection News

    ERIC Educational Resources Information Center

    Literacy Information and Communication System, 2011

    2011-01-01

    This edition of "'LINCS' Resource Collection News" features the Workforce Competitiveness Collection, covering the topics of workforce education, English language acquisition, and technology. Each month Collections News features one of the three "LINCS" (Literacy Information and Communication System) Resource Collections--Basic Skills, Program…

  4. Collection Directions: Some Reflections on the Future of Library Collections and Collecting

    ERIC Educational Resources Information Center

    Dempsey, Lorcan; Malpas, Constance; Lavoie, Brian

    2014-01-01

    This article takes a broad view of the evolution of collecting behaviors in a network environment and suggests some future directions based on various simple models. The authors look at the changing dynamics of print collections, at the greater engagement with research and learning behaviors, and at trends in scholarly communication. The goal is…

  5. Curvature Interaction in Collective Space

    NASA Astrophysics Data System (ADS)

    Herrmann, Richard

    2012-12-01

    For the Riemannian space, built from the collective coordinates used within nuclear models, an additional interaction with the metric is investigated, using the collective equivalent to Einstein's curvature scalar. The coupling strength is determined using a fit with the AME2003 ground state masses. An extended finite-range droplet model including curvature is introduced, which generates significant improvements for light nuclei and nuclei in the trans-fermium region.

  6. Leadership, collective personality, and performance.

    PubMed

    Hofmann, David A; Jones, Lisa M

    2005-05-01

    By viewing behavior regularities at the individual and collective level as functionally isomorphic, a referent-shift compositional model for the Big 5 personality dimensions is developed. On the basis of this compositional model, a common measure of Big 5 personality at the individual level is applied to the collective as a whole. Within this framework, it is also hypothesized that leadership (i.e., transformational, transactional, and passive) would predict collective personality and that collective personality would be significantly related to collective performance. The results supported these hypotheses using a sample of franchised units. On the basis of recent research at the individual level, several interactions among the various personality dimensions were hypothesized and supported. Implications are discussed. PMID:15910146

  7. Perturbative and non-perturbative aspects in vector model/higher spin duality

    NASA Astrophysics Data System (ADS)

    Jevicki, Antal; Jin, Kewang; Ye, Qibin

    2013-05-01

    We review some recent work on AdS/CFT duality involving the 3D O(N) vector model and AdS4 higher spin gravity. Our construction is based on bi-local collective field theory which provides an off-shell formulation of higher spin gravity with G = 1/N playing the role of a coupling constant. Consequently, perturbative and non-perturbative issues of the theory can be studied. For the correspondence based on free CFTs we discuss the nature of bulk 1/N interactions through an S-matrix which is argued to be equal to 1 (Coleman-Mandula theorem). As a consequence in this class of theories nonlinearities are removable, through a nonlinear field transformation which we show at the exact level. We also describe a geometric (Kähler space) framework for the bi-local theory which applies equally simply to Sp(2N) fermions and the de Sitter correspondence. We discuss in this framework the structure and size of the bi-local Hilbert space and the implementation of (finite N) exclusion principle. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Higher spin theories and holography’.

  8. Collections Management, Collections Maintenance, and Conservation.

    ERIC Educational Resources Information Center

    American Association of Museums, Washington, DC.

    This national survey of the state of the nation's museum collections investigates collection care policies and practices, conservation issues, and private sector and federal support for museum needs. It consists of two major projects and four additional information gathering projects. The Museum Collection Survey is designed to examine all major…

  9. ThermoFit: A Set of Software Tools, Protocols and Schema for the Organization of Thermodynamic Data and for the Development, Maintenance, and Distribution of Internally Consistent Thermodynamic Data/Model Collections

    NASA Astrophysics Data System (ADS)

    Ghiorso, M. S.

    2013-12-01

    Internally consistent thermodynamic databases are critical resources that facilitate the calculation of heterogeneous phase equilibria and thereby support geochemical, petrological, and geodynamical modeling. These 'databases' are actually derived data/model systems that depend on a diverse suite of physical property measurements, calorimetric data, and experimental phase equilibrium brackets. In addition, such databases are calibrated with the adoption of various models for extrapolation of heat capacities and volumetric equations of state to elevated temperature and pressure conditions. Finally, these databases require specification of thermochemical models for the mixing properties of solid, liquid, and fluid solutions, which are often rooted in physical theory and, in turn, depend on additional experimental observations. The process of 'calibrating' a thermochemical database involves considerable effort and an extensive computational infrastructure. Because of these complexities, the community tends to rely on a small number of thermochemical databases, generated by a few researchers; these databases often have limited longevity and are universally difficult to maintain. ThermoFit is a software framework and user interface whose aim is to provide a modeling environment that facilitates creation, maintenance and distribution of thermodynamic data/model collections. Underlying ThermoFit are data archives of fundamental physical property, calorimetric, crystallographic, and phase equilibrium constraints that provide the essential experimental information from which thermodynamic databases are traditionally calibrated. ThermoFit standardizes schema for accessing these data archives and provides web services for data mining these collections. Beyond simple data management and interoperability, ThermoFit provides a collection of visualization and software modeling tools that streamline the model/database generation process. Most notably, ThermoFit facilitates the

  10. Learning and dynamics in social systems. Comment on "Collective learning modeling based on the kinetic theory of active particles" by D. Burini et al.

    NASA Astrophysics Data System (ADS)

    Dolfin, Marina

    2016-03-01

    The interesting novelty of the paper by Burini et al. [1] is that the authors present a survey and a new approach of collective learning based on suitable development of methods of the kinetic theory [2] and theoretical tools of evolutionary game theory [3]. Methods of statistical dynamics and kinetic theory lead naturally to stochastic and collective dynamics. Indeed, the authors propose the use of games where the state of the interacting entities is delivered by probability distributions.

  11. Collecting a multi-disciplinary field dataset to model the interactions between a flood control reservoir and the underlying porous aquifer

    NASA Astrophysics Data System (ADS)

    Borgatti, L.; Corsini, A.; Chiapponi, L.; D'Oria, M.; Giuffredi, F.; Lancellotta, R.; Mignosa, P.; Moretti, G.; Orlandini, S.; Pellegrini, M.; Remitti, F.; Ronchetti, F.; Tanda, M.; Zanini, A.

    2008-12-01

    and relatively thin silty and clayey strata. The aquifer can be simplified in three layers: a phreatic aquifer (from 0 to 20 m depth), a thin clayey layer (20 to 25 m) and a regional semi-confined aquifer (beneath 25 m), whose level tend to respond to the reservoir levels. The multidisciplinary database collected so far is the basis of a numerical model that is going to be developed to understand the interactions between the reservoir and the aquifer, in different scenarios.

  12. A matrix model from string field theory

    NASA Astrophysics Data System (ADS)

    Zeze, Syoji

    2016-09-01

    We demonstrate that a Hermitian matrix model can be derived from level truncated open string field theory with Chan-Paton factors. The Hermitian matrix is coupled with a scalar and U(N) vectors which are responsible for the D-brane at the tachyon vacuum. Effective potential for the scalar is evaluated both for finite and large N. Increase of potential height is observed in both cases. The large N matrix integral is identified with a system of N ZZ branes and a ghost FZZT brane.

  13. The Committee on Institutional Cooperation Electronic Journals Collection (CIC-EJC): A New Model for Library Management of Scholarly Journals Published on the Internet.

    ERIC Educational Resources Information Center

    MacEwan, Bonnie; Geffner, Mira

    1996-01-01

    Describes the development of an electronic journal collection placed on the Internet by the Committee on Institutional Cooperation. Topics include publisher approval, archiving and preservation, World Wide Web home page design, cataloging standardization, and staffing. Concludes with a discussion on the future of the resource and the…

  14. Print Capitalism, New School and Circulation of Reading Models. A Brazilian Collection at the Primary Education Museum-Library in Portugal (1931-1950)

    ERIC Educational Resources Information Center

    Toledo, Maria Rita Almeida; Carvalho, Marta Maria Chagas

    2011-01-01

    The present article is the fruit of research on the circulation of Brazilian books from the "Atualidades Pedagogicas" collection at the "Biblioteca Museu do Ensino Primario" (Primary Education Museum-Library) in Lisbon. This library was headed by Adolfo Lima, one of the exponents of the Portuguese New School, and gave form to the movement's ideas…

  15. Collection Development Policy.

    ERIC Educational Resources Information Center

    Monk, John S.

    This document outlines the collection development policies for the Eisenhower National Clearinghouse for Mathematics and Science Education (ENC). It details the clientele the collection is intended to serve, the scope and boundary of the collection, the methods employed to identify and acquire resources for the collection, the selection and…

  16. AMBIENT PARTICULATE MATTER EXPOSURES: A COMPARISON OF SHEDS-PM EXPOSURE MODEL PREDICTIONS AND ESTIMATES DERIVED FROM MEASUREMENTS COLLECTED DURING NERL'S RTP PM PANEL STUDY

    EPA Science Inventory

    The US EPA National Exposure Research Laboratory (NERL) is currently refining and evaluating a population exposure model for particulate matter (PM), called the Stochastic Human Exposure and Dose Simulation (SHEDS-PM) model. The SHEDS-PM model estimates the population distribu...

  17. Controlling Collective Behaviors of Dictyostelium

    NASA Astrophysics Data System (ADS)

    Schwab, David; Mehta, Pankaj; Gregor, Thomas

    2010-03-01

    We study the collective dynamics of a population of Dictyostelium cells, focusing on how single cell dynamics influence, and give rise to, the behavior of the aggregate. Through analysis of quantitative single cell experiments, we develop a simple model of the single cell response to time-dependent pulses of the extracellular signaling molecule cAMP, characterized by a particular type of excitable system. We then use this model to study collective multicellular dynamics mediated by diffusion coupling. We first consider the mean-field case where we find an intriguing ``dynamical quorum sensing'' transition in which all cells simultaneously transition from quiescent to oscillating across the phase boundary. Then we include spatial dynamics and study pattern formation, both with and without the cells capable of chemotactic response to signal gradients. Finally, we highlight how modification of single cells can alter the collective dynamics.

  18. The neurobiology of collective action

    PubMed Central

    Zak, Paul J.; Barraza, Jorge A.

    2013-01-01

    This essay introduces a neurologically-informed mathematical model of collective action (CA) that reveals the role for empathy and distress in motivating costly helping behaviors. We report three direct tests of model with a key focus on the neuropeptide oxytocin as well as a variety of indirect tests. These studies, from our lab and other researchers, show support for the model. Our findings indicate that empathic concern, via the brain's release of oxytocin, is a trigger for CA. We discuss the implications from this model for our understanding why human beings engage in costly CA. PMID:24311995

  19. Wyoming greater sage-grouse habitat prioritization: a collection of multi-scale seasonal models and geographic information systems land management tools

    USGS Publications Warehouse

    O'Donnell, Michael S.; Aldridge, Cameron L.; Doherty, Kevin E.; Fedy, Bradley C.

    2015-01-01

    We deliver all products described herein as online geographic information system data for visualization and downloading. We outline the data properties for each model and their data inputs, describe the process of selecting appropriate data products for multifarious applications, describe all data products and software, provide newly derived model composites, and discuss how land managers may use the models to inform future sage-grouse studies and potentially refine conservation efforts. The models, software tools, and associated opportunities for novel applications of these products should provide a suite of additional, but not exclusive, tools for assessing Wyoming Greater Sage-grouse habitats, which land managers, conservationists, and scientists can apply to myriad applications.

  20. The Multiage Classroom: A Collection.

    ERIC Educational Resources Information Center

    Fogarty, Robin, Ed.

    Noting that the recent call for holistic models of schooling dictates a thorough investigation of more natural groupings of students, this collection of articles reviews available literature on multiage, nongraded, continuous progress classrooms. Divided into six sections, the chapters explore the overriding concerns and the pros and cons of such…

  1. Collection Mode Lens System

    DOEpatents

    Fletcher, Daniel A.; Kino, Gordon S.

    2002-11-05

    A lens system including a collection lens and a microlens spaced from the collection lens adjacent the region to be observed. The diameter of the observablel region depends substantially on the radius of the microlens.

  2. Guide to data collection

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Guidelines and recommendations are presented for the collection of software development data. Motivation and planning for, and implementation and management of, a data collection effort are discussed. Topics covered include types, sources, and availability of data; methods and costs of data collection; types of analyses supported; and warnings and suggestions based on software engineering laboratory (SEL) experiences. This document is intended as a practical guide for software managers and engineers, abstracted and generalized from 5 years of SEL data collection.

  3. What Is a Collection?

    ERIC Educational Resources Information Center

    Lee, Hur-Li

    2000-01-01

    Examines traditional conceptions of a library collection, and reveals four major presumptions associated with collections: tangibility, ownership, a user community, and an integrated retrieval mechanism. Explores challenges posed by media, and proposes an expanded concept of collection that considers the perspectives of both user and collection…

  4. Student Loan Collection Procedures.

    ERIC Educational Resources Information Center

    National Association of College and University Business Officers, Washington, DC.

    This manual on the collection of student loans is intended for the use of business officers and loan collection personnel of colleges and universities of all sizes. The introductory chapter is an overview of sound collection practices and procedures. It discusses the making of a loan, in-school servicing of the accounts, the exit interview, the…

  5. Collection Development Project.

    ERIC Educational Resources Information Center

    Nuby, Mary

    Undertaken to provide data on the current status of collection development in selected academic libraries, this study also analyzed the structure of the collection development function at Chicago Academic Library Council (CALC) institutions and outlined a formal collection development policy for Chicago State University's Douglas Library.…

  6. Computational modelling of the piglet brain to simulate near-infrared spectroscopy and magnetic resonance spectroscopy data collected during oxygen deprivation.

    PubMed

    Moroz, Tracy; Banaji, Murad; Robertson, Nicola J; Cooper, Chris E; Tachtsidis, Ilias

    2012-07-01

    We describe a computational model to simulate measurements from near-infrared spectroscopy (NIRS) and magnetic resonance spectroscopy (MRS) in the piglet brain. Piglets are often subjected to anoxic, hypoxic and ischaemic insults, as experimental models for human neonates. The model aims to help interpret measurements and increase understanding of physiological processes occurring during such insults. It is an extension of a previous model of circulation and mitochondrial metabolism. This was developed to predict NIRS measurements in the brains of healthy adults i.e. concentration changes of oxyhaemoglobin and deoxyhaemoglobin and redox state changes of cytochrome c oxidase (CCO). We altered and enhanced the model to apply to the anaesthetized piglet brain. It now includes metabolites measured by (31)P-MRS, namely phosphocreatine, inorganic phosphate and adenosine triphosphate (ATP). It also includes simple descriptions of glycolysis, lactate dynamics and the tricarboxylic acid (TCA) cycle. The model is described, and its simulations compared with existing measurements from piglets during anoxia. The NIRS and MRS measurements are predicted well, although this requires a reduction in blood pressure autoregulation. Predictions of the cerebral metabolic rate of oxygen consumption (CMRO(2)) and lactate concentration, which were not measured, are given. Finally, the model is used to investigate hypotheses regarding changes in CCO redox state during anoxia.

  7. The (kinetic) theory of active particles applied to learning dynamics. Comment on "Collective learning modeling based on the kinetic theory of active particles" by D. Burini et al.

    NASA Astrophysics Data System (ADS)

    Nieto, J.

    2016-03-01

    The learning phenomena, their complexity, concepts, structure, suitable theories and models, have been extensively treated in the mathematical literature in the last century, and [4] contains a very good introduction to the literature describing the many approaches and lines of research developed about them. Two main schools have to be pointed out [5] in order to understand the two -not exclusive- kinds of existing models: the stimulus sampling models and the stochastic learning models. Also [6] should be mentioned as a survey where two methods of learning are pointed out, the cognitive and the social, and where the knowledge looks like a mathematical unknown. Finally, as the authors do, we refer to the works [9,10], where the concept of population thinking was introduced and which motivate the game theory rules as a tool (both included in [4] to develop their theory) and [7], where the ideas of developing a mathematical kinetic theory of perception and learning were proposed.

  8. Guide for data collection to calibrate a predictive digital ground-water model of the unconfined aquifer in and near the city of Modesto, California

    USGS Publications Warehouse

    Page, R.W.

    1977-01-01

    The city of Modesto encompasses about 12 square miles in the northeastern part of the San Joaquin Valley, Calif. The ground-water model encompasses about 542 square miles. In the Modesto area, ground water occurs in an unconfined aquifer a confined aquifer. both of which are composed of unconsolidated materials, and a consolidated-rock aquifer. Only the unconfined aquifer was modeled, using several simplifying assumptions concerning hydrologic conditions in the ground-water basin. A program is used that computes the net rate of recharge and discharge under steady-state conditions. The model was then modified until reasonable values of recharge and discharge were computed. Testing of the model indicated that simulated water levels were especially sensitive to tansmissivity, storage coefficient, irrigation return, and riverbed hydraulic conductivity; amond the parameters that affected water levels least were the vertical hydraulic conductivity and specific storage of the confining bed, the so-called E-clay. (Woodard-USGS)

  9. Information on living systems: A kinetic approach. Comment on the paper "Collective learning modeling based on the kinetic theory of active particles" by D. Burini et al.

    NASA Astrophysics Data System (ADS)

    Urrutia, L.

    2016-03-01

    Information appears naturally in the description of living systems. In kinetic models of such systems, information defined as the knowledge that a population has of the structure of the environment plays a key role in the dynamics of the system. For example, on chemotaxis models of cell movement, the concentration of a certain chemical substance can be understood to be the information that cells have of the structure of the surrounding media, and adapt their movement to that [6,7].

  10. Remote application for spectral collection

    NASA Astrophysics Data System (ADS)

    Cone, Shelli R.; Steele, R. J.; Tzeng, Nigel H.; Firpi, Alexer H.; Rodriguez, Benjamin M.

    2016-05-01

    In the area of collecting field spectral data using a spectrometer, it is common to have the instrument over the material of interest. In certain instances it is beneficial to have the ability to remotely control the spectrometer. While several systems have the ability to use a form of connectivity to capture the measurement it is essential to have the ability to control the settings. Additionally, capturing reference information (metadata) about the setup, system configuration, collection, location, atmospheric conditions, and sample information is necessary for future analysis leading towards material discrimination and identification. This has the potential to lead to cumbersome field collection and a lack of necessary information for post processing and analysis. The method presented in this paper describes a capability to merge all parts of spectral collection from logging reference information to initial analysis as well as importing information into a web-hosted spectral database. This allows the simplification of collecting, processing, analyzing and storing field spectra for future analysis and comparisons. This concept is developed for field collection of thermal data using the Designs and Prototypes (D&P) Hand Portable FT-IR Spectrometer (Model 102). The remote control of the spectrometer is done with a customized Android application allowing the ability to capture reference information, process the collected data from radiance to emissivity using a temperature emissivity separation algorithm and store the data into a custom web-based service. The presented system of systems allows field collected spectra to be used for various applications by spectral analysts in the future.

  11. Collective Behaviour without Collective Order in Wild Swarms of Midges

    PubMed Central

    Attanasi, Alessandro; Cavagna, Andrea; Del Castello, Lorenzo; Giardina, Irene; Melillo, Stefania; Parisi, Leonardo; Pohl, Oliver; Rossaro, Bruno; Shen, Edward; Silvestri, Edmondo; Viale, Massimiliano

    2014-01-01

    Collective behaviour is a widespread phenomenon in biology, cutting through a huge span of scales, from cell colonies up to bird flocks and fish schools. The most prominent trait of collective behaviour is the emergence of global order: individuals synchronize their states, giving the stunning impression that the group behaves as one. In many biological systems, though, it is unclear whether global order is present. A paradigmatic case is that of insect swarms, whose erratic movements seem to suggest that group formation is a mere epiphenomenon of the independent interaction of each individual with an external landmark. In these cases, whether or not the group behaves truly collectively is debated. Here, we experimentally study swarms of midges in the field and measure how much the change of direction of one midge affects that of other individuals. We discover that, despite the lack of collective order, swarms display very strong correlations, totally incompatible with models of non-interacting particles. We find that correlation increases sharply with the swarm's density, indicating that the interaction between midges is based on a metric perception mechanism. By means of numerical simulations we demonstrate that such growing correlation is typical of a system close to an ordering transition. Our findings suggest that correlation, rather than order, is the true hallmark of collective behaviour in biological systems. PMID:25057853

  12. Collective neutrino oscillations and spontaneous symmetry breaking

    NASA Astrophysics Data System (ADS)

    Duan, Huaiyu

    2015-08-01

    Neutrino oscillations in a hot and dense astrophysical environment such as a core-collapse supernova pose a challenging, seven-dimensional flavor transport problem. To make the problem even more difficult (and interesting), neutrinos can experience collective oscillations through nonlinear refraction in the dense neutrino medium in this environment. Significant progress has been made in the last decade towards the understanding of collective neutrino oscillations in various simplified neutrino gas models with imposed symmetries and reduced dimensions. However, a series of recent studies seem to have "reset" this progress by showing that these models may not be compatible with collective neutrino oscillations because the latter can break the symmetries spontaneously if they are not imposed. We review some of the key concepts of collective neutrino oscillations by using a few simple toy models. We also elucidate the breaking of spatial and directional symmetries in these models because of collective oscillations.

  13. The EMBRACE web service collection

    PubMed Central

    Pettifer, Steve; Ison, Jon; Kalaš, Matúš; Thorne, Dave; McDermott, Philip; Jonassen, Inge; Liaquat, Ali; Fernández, José M.; Rodriguez, Jose M.; Partners, INB-; Pisano, David G.; Blanchet, Christophe; Uludag, Mahmut; Rice, Peter; Bartaseviciute, Edita; Rapacki, Kristoffer; Hekkelman, Maarten; Sand, Olivier; Stockinger, Heinz; Clegg, Andrew B.; Bongcam-Rudloff, Erik; Salzemann, Jean; Breton, Vincent; Attwood, Teresa K.; Cameron, Graham; Vriend, Gert

    2010-01-01

    The EMBRACE (European Model for Bioinformatics Research and Community Education) web service collection is the culmination of a 5-year project that set out to investigate issues involved in developing and deploying web services for use in the life sciences. The project concluded that in order for web services to achieve widespread adoption, standards must be defined for the choice of web service technology, for semantically annotating both service function and the data exchanged, and a mechanism for discovering services must be provided. Building on this, the project developed: EDAM, an ontology for describing life science web services; BioXSD, a schema for exchanging data between services; and a centralized registry (http://www.embraceregistry.net) that collects together around 1000 services developed by the consortium partners. This article presents the current status of the collection and its associated recommendations and standards definitions. PMID:20462862

  14. Evaluation of convection-permitting model simulations of cloud populations associated with the Madden-Julian Oscillation using data collected during the AMIE/DYNAMO field campaign

    SciTech Connect

    Hagos, Samson M.; Feng, Zhe; Burleyson, Casey D.; Lim, Kyo-Sun; Long, Charles N.; Wu, Di; Thompson, Gregory

    2014-11-12

    Regional cloud permitting model simulations of cloud populations observed during the 2011 ARM Madden Julian Oscillation Investigation Experiment/ Dynamics of Madden-Julian Experiment (AMIE/DYNAMO) field campaign are evaluated against radar and ship-based measurements. Sensitivity of model simulated surface rain rate statistics to parameters and parameterization of hydrometeor sizes in five commonly used WRF microphysics schemes are examined. It is shown that at 2 km grid spacing, the model generally overestimates rain rate from large and deep convective cores. Sensitivity runs involving variation of parameters that affect rain drop or ice particle size distribution (more aggressive break-up process etc) generally reduce the bias in rain-rate and boundary layer temperature statistics as the smaller particles become more vulnerable to evaporation. Furthermore significant improvement in the convective rain-rate statistics is observed when the horizontal grid-spacing is reduced to 1 km and 0.5 km, while it is worsened when run at 4 km grid spacing as increased turbulence enhances evaporation. The results suggest modulation of evaporation processes, through parameterization of turbulent mixing and break-up of hydrometeors may provide a potential avenue for correcting cloud statistics and associated boundary layer temperature biases in regional and global cloud permitting model simulations.

  15. Aquatic Vegetation of the St. Louis River Estuary: Initial Analysis of Point-intercept Data Collected in 2010 for Restoration Modeling.

    EPA Science Inventory

    A new effort to model aquatic vegetation patterns in the St. Louis River Estuary was initiated in summer of 2010 for the purpose of informing wetland restoration planning in the St. Louis River Area of Concern (AOC) at 40th Avenue West in Duluth. Aquatic vascular plants were doc...

  16. Solar energy collection system

    NASA Technical Reports Server (NTRS)

    Selcuk, M. K. (Inventor)

    1977-01-01

    An improved solar energy collection system, having enhanced energy collection and conversion capabilities, is delineated. The system is characterized by a plurality of receivers suspended above a heliostat field comprising a multiplicity of reflector surfaces, each being adapted to direct a concentrated beam of solar energy to illuminate a target surface for a given receiver. A magnitude of efficiency, suitable for effectively competing with systems employed in collecting and converting energy extracted from fossil fuels, is indicated.

  17. Distributed resource management: garbage collection

    SciTech Connect

    Bagherzadeh, N.

    1987-01-01

    In recent years, there has been a great interest in designing high-performance distributed symbolic-processing computers. These architectures have special needs for resource management and dynamic reclamation of unused memory cells and objects. The memory management or garbage-collection aspects of these architectures are studied. Also introduced is a synchronous distributed algorithm for garbage collection. A special data structure is defined to handle the distributed nature of the problem. The author formally expresses the algorithm and shows the results of a synchronous garbage-collection simulation and its effect on the interconnection-network message to traffic. He presents an asynchronous distributed garbage collection to handle the resource management for a system that does not require a global synchronization mechanism. The distributed data structure is modified to include the asynchronous aspects of the algorithm. This method is extended to a multiple-mutator scheme, and the problem of having several processors share portion of a cyclical graph is discussed. Two models for the analytical study of the garbage-collection algorithms discussed are provided.

  18. From particle systems to learning processes. Comment on "Collective learning modeling based on the kinetic theory of active particles" by Diletta Burini, Silvana De Lillo, and Livio Gibelli

    NASA Astrophysics Data System (ADS)

    Lachowicz, Mirosław

    2016-03-01

    The very stimulating paper [6] discusses an approach to perception and learning in a large population of living agents. The approach is based on a generalization of kinetic theory methods in which the interactions between agents are described in terms of game theory. Such an approach was already discussed in Ref. [2-4] (see also references therein) in various contexts. The processes of perception and learning are based on the interactions between agents and therefore the general kinetic theory is a suitable tool for modeling them. However the main question that rises is how the perception and learning processes may be treated in the mathematical modeling. How may we precisely deliver suitable mathematical structures that are able to capture various aspects of perception and learning?

  19. Composite collective decision-making

    PubMed Central

    Czaczkes, Tomer J.; Czaczkes, Benjamin; Iglhaut, Carolin; Heinze, Jürgen

    2015-01-01

    Individual animals are adept at making decisions and have cognitive abilities, such as memory, which allow them to hone their decisions. Social animals can also share information. This allows social animals to make adaptive group-level decisions. Both individual and collective decision-making systems also have drawbacks and limitations, and while both are well studied, the interaction between them is still poorly understood. Here, we study how individual and collective decision-making interact during ant foraging. We first gathered empirical data on memory-based foraging persistence in the ant Lasius niger. We used these data to create an agent-based model where ants may use social information (trail pheromones), private information (memories) or both to make foraging decisions. The combined use of social and private information by individuals results in greater efficiency at the group level than when either information source was used alone. The modelled ants couple consensus decision-making, allowing them to quickly exploit high-quality food sources, and combined decision-making, allowing different individuals to specialize in exploiting different resource patches. Such a composite collective decision-making system reaps the benefits of both its constituent parts. Exploiting such insights into composite collective decision-making may lead to improved decision-making algorithms. PMID:26019155

  20. Composite collective decision-making.

    PubMed

    Czaczkes, Tomer J; Czaczkes, Benjamin; Iglhaut, Carolin; Heinze, Jürgen

    2015-06-22

    Individual animals are adept at making decisions and have cognitive abilities, such as memory, which allow them to hone their decisions. Social animals can also share information. This allows social animals to make adaptive group-level decisions. Both individual and collective decision-making systems also have drawbacks and limitations, and while both are well studied, the interaction between them is still poorly understood. Here, we study how individual and collective decision-making interact during ant foraging. We first gathered empirical data on memory-based foraging persistence in the ant Lasius niger. We used these data to create an agent-based model where ants may use social information (trail pheromones), private information (memories) or both to make foraging decisions. The combined use of social and private information by individuals results in greater efficiency at the group level than when either information source was used alone. The modelled ants couple consensus decision-making, allowing them to quickly exploit high-quality food sources, and combined decision-making, allowing different individuals to specialize in exploiting different resource patches. Such a composite collective decision-making system reaps the benefits of both its constituent parts. Exploiting such insights into composite collective decision-making may lead to improved decision-making algorithms.

  1. Composite collective decision-making.

    PubMed

    Czaczkes, Tomer J; Czaczkes, Benjamin; Iglhaut, Carolin; Heinze, Jürgen

    2015-06-22

    Individual animals are adept at making decisions and have cognitive abilities, such as memory, which allow them to hone their decisions. Social animals can also share information. This allows social animals to make adaptive group-level decisions. Both individual and collective decision-making systems also have drawbacks and limitations, and while both are well studied, the interaction between them is still poorly understood. Here, we study how individual and collective decision-making interact during ant foraging. We first gathered empirical data on memory-based foraging persistence in the ant Lasius niger. We used these data to create an agent-based model where ants may use social information (trail pheromones), private information (memories) or both to make foraging decisions. The combined use of social and private information by individuals results in greater efficiency at the group level than when either information source was used alone. The modelled ants couple consensus decision-making, allowing them to quickly exploit high-quality food sources, and combined decision-making, allowing different individuals to specialize in exploiting different resource patches. Such a composite collective decision-making system reaps the benefits of both its constituent parts. Exploiting such insights into composite collective decision-making may lead to improved decision-making algorithms. PMID:26019155

  2. The Feasibility of Collecting School Nurse Data.

    PubMed

    Bergren, Martha Dewey

    2016-10-01

    School nurses cite barriers to collecting comprehensive data on the care they provide. This study evaluated the feasibility of collecting school nurse data on selected child health and education outcomes. Outcome variables included school health office visits; health provider, parent, and staff communication; early dismissal; and medications administered. On an average day, the school nurses cared for 43.5 students, administered 14 medications, and averaged of 17 daily communications. Day 1 data collection times averaged 15 min or less. By Day 5, 6.6 min was needed to complete the survey. Data collection was feasible for 76% of those who elected to participate. Feasibility is enhanced by limiting the number of data points and the number of days for data collection using a data collection web interface. Data collection across large numbers of nurses and a wide range of school nurse delivery models is necessary to measure the impact of school nurse presence and interventions on child health and education outcomes.

  3. Profiling a Periodicals Collection

    ERIC Educational Resources Information Center

    Bolgiano, Christina E.; King, Mary Kathryn

    1978-01-01

    Libraries need solid information upon which to base collection development decisions. Specific evaluative methods for determining scope, access, and usefullness are described. Approaches used for data collection include analysis of interlibrary loan requests, comparison with major bibliographies, and analysis of accessibility through available…

  4. Collecting Best Practices

    ERIC Educational Resources Information Center

    Tedford, Jennifer

    2008-01-01

    How many beginning teachers struggle to create new lessons despite the fact that experienced teachers have already designed effective lessons for the same content? Shulman (1987) used the term "collective amnesia" to describe the failure of school leaders to design professional development that included the collection of its best practices.…

  5. Collection Development Policy.

    ERIC Educational Resources Information Center

    Casserly, Mary

    In this document the collection goals of the William Paterson New Jersey State College library are enumerated and the policies and procedures of the library regarding the selection and acquisition of different types of materials are summarized. Following a short introduction to the function of collection development policies is a general statement…

  6. Children's Collective Training Manual.

    ERIC Educational Resources Information Center

    Kimbrough, Jackie; And Others

    This children's collective manual describes a training program for parents and teachers of preschool children which is designed to encourage cooperative, community-oriented styles of group interaction in black preschool children. Developed by the Children's Collective of the Coordinated Child Care Council of South Los Angeles, the program is based…

  7. Debt collection project report

    SciTech Connect

    Not Available

    1980-05-01

    In October 1979 the Office of Management and Budget initiated a review of debt collection within the Federal Government. A DOE Debt Collection Project Team was established, and seven activites were selected for review. These were Albuquerque Operations Office; Bonneville Power Administration; Chicago Operations and Regional Office; Naval Petroleum Reserves, California; Oak Ridge Operations Office; Washington Financial Services Division; and Western Area Power Administration. The team visited each of these activities to collect data on the size, age, and types of receivables managed and procedures for billing, aging, and handling overdue accounts. Various deficiencies were found to exist at several of the DOE entities that are not consistent with good management practices in the performance of their debt collection functions. Also, the Debt Collection Project Team identified a wide variation in the procedures followed by DOE activities in the management of accounts receivable, and a wide variation in the effectiveness of the debt management functions. 1 figure, 17 tables. (RWR)

  8. Urine collection device

    NASA Technical Reports Server (NTRS)

    Michaud, R. B. (Inventor)

    1981-01-01

    A urine collection device for females is described. It is comprised of a collection element defining a urine collection chamber and an inlet opening into the chamber and is adapted to be disposed in surrounding relation to the urethral opening of the user. A drainage conduit is connected to the collection element in communication with the chamber whereby the chamber and conduit together comprise a urine flow pathway for carrying urine generally away from the inlet. A first body of wicking material is mounted adjacent the collection element and extends at least partially into the flow pathway. The device preferably also comprise a vaginal insert element including a seal portion for preventing the entry of urine into the vagina.

  9. 75 FR 25203 - Proposed Information Collection; Comment Request; Regional Economic Data Collection Program for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-07

    ... associated with fishery management policies, appropriate economic models and the data to implement them are... effort, data on these important regional economic variables will be collected and used to develop models... Economic Data Collection Program for Southeast Alaska AGENCY: National Oceanic and...

  10. The Perception and Classification of Collective Behavior

    ERIC Educational Resources Information Center

    Russell, Gordon W.

    1972-01-01

    A classificatory model of collective behavior based upon perceptual dimensions was proposed. The four major dimensions found to underlie a domain of collective phenomena were identified as: (a) Violence, (b) Amorphous-Focused, (c) Anomie, and (d) Ideology. Potentially predictive aspects of the system were examined briefly. (Author)

  11. Management Strategies for Promoting Teacher Collective Learning

    ERIC Educational Resources Information Center

    Cheng, Eric C. K.

    2011-01-01

    This paper aims to validate a theoretical model for developing teacher collective learning by using a quasi-experimental design, and explores the management strategies that would provide a school administrator practical steps to effectively promote collective learning in the school organization. Twenty aided secondary schools in Hong Kong were…

  12. 76 FR 67668 - Proposed Collection; Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-02

    ... methods: Electronic: http://www.regulations.gov . Follow the instructions for submitting comments. Mail... variety of collection methods, including interviews and research, to inform the design, development and implementation of the model form(s). The information collected through qualitative evaluation methods will...

  13. RESULTS FROM THE (1) DATA COLLECTION WORKSHOP, (2) MODELING WORKSHOP AND (3) DRILLING AND CORING METHODS WORKSHOP AS PART OF THE JOINT INDUSTRY PARTICIPATION (JIP) PROJECT TO CHARACTERIZE NATURAL GAS HYDRATES IN THE DEEPWATER GULF OF MEXICO

    SciTech Connect

    Stephen A. Holditch; Emrys Jones

    2002-09-01

    In 2000, Chevron began a project to learn how to characterize the natural gas hydrate deposits in the deepwater portions of the Gulf of Mexico. A Joint Industry Participation (JIP) group was formed in 2001, and a project partially funded by the U.S. Department of Energy (DOE) began in October 2001. The primary objective of this project is to develop technology and data to assist in the characterization of naturally occurring gas hydrates in the deepwater Gulf of Mexico. These naturally occurring gas hydrates can cause problems relating to drilling and production of oil and gas, as well as building and operating pipelines. Other objectives of this project are to better understand how natural gas hydrates can affect seafloor stability, to gather data that can be used to study climate change, and to determine how the results of this project can be used to assess if and how gas hydrates act as a trapping mechanism for shallow oil or gas reservoirs. As part of the project, three workshops were held. The first was a data collection workshop, held in Houston during March 14-15, 2002. The purpose of this workshop was to find out what data exist on gas hydrates and to begin making that data available to the JIP. The second and third workshop, on Geoscience and Reservoir Modeling, and Drilling and Coring Methods, respectively, were held simultaneously in Houston during May 9-10, 2002. The Modeling Workshop was conducted to find out what data the various engineers, scientists and geoscientists want the JIP to collect in both the field and the laboratory. The Drilling and Coring workshop was to begin making plans on how we can collect the data required by the project's principal investigators.

  14. The Rhoton Collection.

    PubMed

    Sorenson, Jeffrey; Khan, Nickalus; Couldwell, William; Robertson, Jon

    2016-08-01

    The Rhoton Collection is an archive of Dr. Al Rhoton Jr.'s anatomical images and video lectures, as well as an anatomical reference. In an effort to maximize the educational impact of these teaching materials, web-based technologies are used to dynamically format this material for a variety of devices ranging from cellular phones to projectors. Surgical cases are cross-referenced to further enhance the usefulness of this collection, which is available at http://rhoton.ineurodb.org. The features of the Rhoton Collection website are described in this article. PMID:27319307

  15. Minimum Cost Estimation of a Baseline Survey for a Molecular Epidemiology Cohort Study: Collecting Participants in a Model Region in Japan

    PubMed Central

    Sawada, Norie; Iwasaki, Motoki; Ohashi, Kayo; Tsugane, Shoichiro

    2016-01-01

    Background Some recent molecular epidemiology studies of the effects of genetic and environmental factors on human health have required the enrollment of more than 100 000 participants and the involvement of regional study offices across the country. Although regional study office investigators play a critical role in these studies, including the acquisition of funds, this role is rarely discussed. Methods We first differentiated the functions of the regional and central study offices. We then investigated the minimum number of items required and approximate cost of a molecular epidemiology study enrolling 7400 participants from a model region with a population of 100 000 for a 4-year baseline survey using a standard protocol developed based on the protocol of Japan Public Health Center-based Prospective Study for the Next Generation. Results The functions of the regional study office were identified, and individual expenses were itemized. The total cost of the 4-year baseline survey was 153 million yen, excluding consumption tax. Accounting difficulties in conducting the survey were clarified. Conclusions We investigated a standardized example of the tasks and total actual costs of a regional study office. Our approach is easy to utilize and will help improve the management of regional study offices in future molecular epidemiology studies. PMID:27001116

  16. Collected software engineering papers, volume 2

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Topics addressed include: summaries of the software engineering laboratory (SEL) organization, operation, and research activities; results of specific research projects in the areas of resource models and software measures; and strategies for data collection for software engineering research.

  17. 78 FR 5171 - Proposed Collection; Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-24

    ... to the Chief of Account Management, Online GEOINT Services--Customer Account Management (OGSU... collection requirement is necessary to develop customer service models regarding consumers of geospatial... 1995, the Online GEOINT Services (OGS) directorate of NGA announces a proposed public...

  18. Sweat collection capsule

    NASA Technical Reports Server (NTRS)

    Delaplaine, R. W.; Greenleaf, J. E.

    1979-01-01

    Capsule, with filter paper insert, is used to collect sweat for rate monitoring, chromatographic analysis, or active sweat gland location within specified area. Construction of capsule allows change of inserts while device remains strapped in place.

  19. Vectorized garbage collection

    SciTech Connect

    Appel, A.W.; Bendiksen, A.

    1988-01-01

    Garbage collection can be done in vector mode on supercomputers like the Cray-2 and the Cyber 205. Both copying collection and mark-and-sweep can be expressed as breadth-first searches in which the queue can be processed in parallel. The authors have designed a copying garbage collector whose inner loop works entirely in vector mode. The only significant limitation of the algorithm is that if the size of the records is not constant, the implementation becomes much more complicated. The authors give performance measurements of the algorithm as implemented for Lisp CONS cells on the Cyber 205. Vector-mode garbage collection performs up to 9 times faster than scalar-mode collection.

  20. Sweat collection capsule

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Delaplaine, R. W. (Inventor)

    1980-01-01

    A sweat collection capsule permitting quantitative collection of sweat is described. The device consists of a frame held immobile on the skin, a closure secured to the frame and absorbent material located next to the skin in a cavity formed by the frame and the closure. The absorbent material may be removed from the device by removing the closure from the frame while the frame is held immobile on the skin.

  1. Collective field accelerator

    DOEpatents

    Luce, John S.

    1978-01-01

    A collective field accelerator which operates with a vacuum diode and utilizes a grooved cathode and a dielectric anode that operates with a relativistic electron beam with a .nu./.gamma. of .about. 1, and a plurality of dielectric lenses having an axial magnetic field thereabout to focus the collectively accelerated electrons and ions which are ejected from the anode. The anode and lenses operate as unoptimized r-f cavities which modulate and focus the beam.

  2. Sparse matrix test collections

    SciTech Connect

    Duff, I.

    1996-12-31

    This workshop will discuss plans for coordinating and developing sets of test matrices for the comparison and testing of sparse linear algebra software. We will talk of plans for the next release (Release 2) of the Harwell-Boeing Collection and recent work on improving the accessibility of this Collection and others through the World Wide Web. There will only be three talks of about 15 to 20 minutes followed by a discussion from the floor.

  3. A Survey of Collectives

    NASA Technical Reports Server (NTRS)

    Tumer, Kagan; Wolpert, David

    2004-01-01

    Due to the increasing sophistication and miniaturization of computational components, complex, distributed systems of interacting agents are becoming ubiquitous. Such systems, where each agent aims to optimize its own performance, but where there is a well-defined set of system-level performance criteria, are called collectives. The fundamental problem in analyzing/designing such systems is in determining how the combined actions of self-interested agents leads to 'coordinated' behavior on a iarge scale. Examples of artificial systems which exhibit such behavior include packet routing across a data network, control of an array of communication satellites, coordination of multiple deployables, and dynamic job scheduling across a distributed computer grid. Examples of natural systems include ecosystems, economies, and the organelles within a living cell. No current scientific discipline provides a thorough understanding of the relation between the structure of collectives and how well they meet their overall performance criteria. Although still very young, research on collectives has resulted in successes both in understanding and designing such systems. It is eqected that as it matures and draws upon other disciplines related to collectives, this field will greatly expand the range of computationally addressable tasks. Moreover, in addition to drawing on them, such a fully developed field of collective intelligence may provide insight into already established scientific fields, such as mechanism design, economics, game theory, and population biology. This chapter provides a survey to the emerging science of collectives.

  4. Collective beating of artificial microcilia.

    PubMed

    Coq, Naïs; Bricard, Antoine; Delapierre, Francois-Damien; Malaquin, Laurent; du Roure, Olivia; Fermigier, Marc; Bartolo, Denis

    2011-07-01

    We combine technical, experimental, and theoretical efforts to investigate the collective dynamics of artificial microcilia in a viscous fluid. We take advantage of soft lithography and colloidal self-assembly to devise microcarpets made of hundreds of slender magnetic rods. This novel experimental setup is used to investigate the dynamics of extended cilia arrays driven by a precessing magnetic field. Whereas the dynamics of an isolated cilium is a rigid body rotation, collective beating results in a symmetry breaking of the precession patterns. The trajectories of the cilia are anisotropic and experience a significant structural evolution as the actuation frequency increases. We present a minimal model to account for our experimental findings and demonstrate how the global geometry of the array imposes the shape of the trajectories via long-range hydrodynamic interactions. PMID:21797546

  5. Optimality, reduction and collective motion

    PubMed Central

    Justh, Eric W.; Krishnaprasad, P. S.

    2015-01-01

    The planar self-steering particle model of agents in a collective gives rise to dynamics on the N-fold direct product of SE(2), the rigid motion group in the plane. Assuming a connected, undirected graph of interaction between agents, we pose a family of symmetric optimal control problems with a coupling parameter capturing the strength of interactions. The Hamiltonian system associated with the necessary conditions for optimality is reducible to a Lie–Poisson dynamical system possessing interesting structure. In particular, the strong coupling limit reveals additional (hidden) symmetry, beyond the manifest one used in reduction: this enables explicit integration of the dynamics, and demonstrates the presence of a ‘master clock’ that governs all agents to steer identically. For finite coupling strength, we show that special solutions exist with steering controls proportional across the collective. These results suggest that optimality principles may provide a framework for understanding imitative behaviours observed in certain animal aggregations. PMID:27547087

  6. Theory of Collective Intelligence

    NASA Technical Reports Server (NTRS)

    Wolpert, David H.

    2003-01-01

    In this chapter an analysis of the behavior of an arbitrary (perhaps massive) collective of computational processes in terms of an associated "world" utility function is presented We concentrate on the situation where each process in the collective can be viewed as though it were striving to maximize its own private utility function. For such situations the central design issue is how to initialize/update the collective's structure, and in particular the private utility functions, so as to induce the overall collective to behave in a way that has large values of the world utility. Traditional "team game" approaches to this problem simply set each private utility function equal to the world utility function. The "Collective Intelligence" (COIN) framework is a semi-formal set of heuristics that recently have been used to construct private utility. functions that in many experiments have resulted in world utility values up to orders of magnitude superior to that ensuing from use of the team game utility. In this paper we introduce a formal mathematics for analyzing and designing collectives. We also use this mathematics to suggest new private utilities that should outperform the COIN heuristics in certain kinds of domains. In accompanying work we use that mathematics to explain previous experimental results concerning the superiority of COIN heuristics. In that accompanying work we also use the mathematics to make numerical predictions, some of which we then test. In this way these two papers establish the study of collectives as a proper science, involving theory, explanation of old experiments, prediction concerning new experiments, and engineering insights.

  7. Flexible human collective wisdom.

    PubMed

    Juni, Mordechai Z; Eckstein, Miguel P

    2015-12-01

    Group decisions typically outperform individual decisions. But how do groups combine their individual decisions to reach their collective decisions? Previous studies conceptualize collective decision making using static combination rules, be it a majority-voting rule or a weighted-averaging rule. Unknown is whether groups adapt their combination rules to changing information environments. We implemented a novel paradigm for which information obeyed a mixture of distributions, such that the optimal Bayesian rule is nonlinear and often follows minority opinions, while the majority rule leads to suboptimal but above chance performance. Using perceptual (Experiment 1) and cognitive (Experiment 2) signal-detection tasks, we switched the information environment halfway through the experiments to a mixture of distributions without informing participants. Groups gradually abandoned the majority rule to follow any minority opinion advocating signal presence with high confidence. Furthermore, groups with greater ability to abandon the majority rule achieved higher collective-decision accuracies. It is important to note that this abandonment was not triggered by performance loss for the majority rule relative to the first half of the experiment. Our results propose a new theory of human collective decision making: Humans make inferences about how information is distributed across individuals and time, and dynamically alter their joint decision algorithms to enhance the benefits of collective wisdom.

  8. The Geneva brain collection

    PubMed Central

    Kövari, Enikö; Hof, Patrick R.; Bouras, Constantin

    2011-01-01

    The University of Geneva brain collection was founded at the beginning of the 20th century. Today, it consists of 10,154 formaldehyde- or buffered formaldehyde–fixed brains obtained from the autopsies of the Department of Psychiatry and, since 1971, from the Department of Geriatrics as well. More than 100,000 paraffin-embedded blocks and 200,000 histological slides have also been collected since 1901. From the time of its creation, this collection has served as an important resource for pathological studies and clinicopathological correlations, primarily in the field of dementing illnesses and brain aging research. These materials have permitted a number of original neuropathological observations, such as the classification of Pick’s disease by Constantinidis, or the description of dyshoric angiopathy and laminar sclerosis by Morel. The large number of cases, including some very rare conditions, provides a unique resource and an opportunity for worldwide collaborations. PMID:21599692

  9. Curating Virtual Data Collections

    NASA Technical Reports Server (NTRS)

    Lynnes, Chris; Leon, Amanda; Ramapriyan, Hampapuram; Tsontos, Vardis; Shie, Chung-Lin; Liu, Zhong

    2015-01-01

    NASAs Earth Observing System Data and Information System (EOSDIS) contains a rich set of datasets and related services throughout its many elements. As a result, locating all the EOSDIS data and related resources relevant to particular science theme can be daunting. This is largely because EOSDIS data's organizing principle is affected more by the way they are produced than around the expected end use. Virtual collections oriented around science themes can overcome this by presenting collections of data and related resources that are organized around the user's interest, not around the way the data were produced. Virtual collections consist of annotated web addresses (URLs) that point to data and related resource addresses, thus avoiding the need to copy all of the relevant data to a single place. These URL addresses can be consumed by a variety of clients, ranging from basic URL downloaders (wget, curl) and web browsers to sophisticated data analysis programs such as the Integrated Data Viewer.

  10. Heat collection system

    SciTech Connect

    Ramlow, B.L.; Steele, R.R.

    1982-04-06

    A heat collection system is disclosed which is capable of collecting heat from an animal husbandry enclosures such as a dairy barn, and transferring the heat into a home. Animal husbandry enclosures, such as dairy barns, tend to have excess heat, even in winter, the excess heat normally being wasted. The heat is collected by a pair of evaporators located in the dairy barn, with the evaporators being oversized to limit the amount of cooling taking place in the barn. Fluid from the evaporators is compressed by compressors after which it passes through a condenser from which heat may be extracted into the home. Pressure regulating valves are provided to insure that the compressors are not overloaded and to insure that a maximum heating effect is achieved. A thermostatically controlled fan is provided to drive air across the condenser so that heat is introduced into the home.

  11. Portable data collection device

    DOEpatents

    French, Patrick D.

    1996-01-01

    The present invention provides a portable data collection device that has a variety of sensors that are interchangeable with a variety of input ports in the device. The various sensors include a data identification feature that provides information to the device regarding the type of physical data produced by each sensor and therefore the type of sensor itself. The data identification feature enables the device to locate the input port where the sensor is connected and self adjust when a sensor is removed or replaced. The device is able to collect physical data, whether or not a function of a time.

  12. Portable data collection device

    DOEpatents

    French, P.D.

    1996-06-11

    The present invention provides a portable data collection device that has a variety of sensors that are interchangeable with a variety of input ports in the device. The various sensors include a data identification feature that provides information to the device regarding the type of physical data produced by each sensor and therefore the type of sensor itself. The data identification feature enables the device to locate the input port where the sensor is connected and self adjust when a sensor is removed or replaced. The device is able to collect physical data, whether or not a function of a time. 7 figs.

  13. Collective modes in neural networks.

    PubMed

    Parikh, J C; Satyan, V; Pratap, R

    1989-02-01

    A theoretical model, based on response of a neural network to an external stimulus, was constructed to determine its collective modes. It is suggested that the waves observed in EEG records reflect the cooperative electrical activity of a large number of neurons. Further, an actual EEG time series was analyzed to deduce two dynamic parameters, dimension d of phase space of the neural system and the minimum number of variables nc necessary to describe the EEG pattern. We find d = 6.2 and nc = 11. PMID:2722419

  14. Collective organization in aerotactic motion

    NASA Astrophysics Data System (ADS)

    Mazza, Marco G.

    Some bacteria exhibit interesting behavior in the presence of an oxygen concentration. They perform an aerotactic motion along the gradient until they reach their optimal oxygen concentration. But they often organize collectively by forming dense regions, called 'bands', that travel towards the oxygen source. We have developed a model of swimmers with stochastic interaction rules moving in proximity of an air bubble. We perform molecular dynamics simulations and also solve advection-diffusion equations that reproduce the aerotactic behavior of mono-flagellated, facultative anaerobic bacteria. If the oxygen concentration in the system sinks locally below a threshold value, the formation of a migrating aerotactic band toward the bubble can be observed.

  15. Materials and Collections

    ERIC Educational Resources Information Center

    Hinseth, Lois

    1978-01-01

    This discussion of collection development considers (1) special problems as they relate to specific types of institutions--nursing, long term residential, psychiatric and developmental; (2) acquisition; (3) organization--classification, cataloging, and physical arrangement; (4) use--circulation, special methods, and the role of librarians; and (5)…

  16. The Fall Collection.

    ERIC Educational Resources Information Center

    VanDeman, Barry A.

    1984-01-01

    Presents ideas for collecting objects on the school grounds or in the surrounding neighborhood. Objects include feathers/fur, leaves, galls, seeds, shells, spiderwebs, and litter. Also presents procedures for making impressions of bark, leaves, fossils, flora, and shadows. All activities can be adopted for students in kindergarten through grade…

  17. Universities and Collective Bargaining.

    ERIC Educational Resources Information Center

    Savage, Donald C.

    1994-01-01

    Responds to David Cameron's "More than an Academic Question" and to the review by Barbara Anderson disagreeing with Cameron's suggestion that democratization and decentralization were a mistake, and arguing for collective bargaining. The paper counters Cameron's support of the continuation of mandatory retirement with reference to the United…

  18. Surface reference data collection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Applications of remote sensing must define relationships between image data and conditions at corresponding points on the ground. Unfortunately, many published remote sensing reports focus on image processing techniques with little detail regarding the methods used for collecting ground truth data....

  19. Television's New Humane Collectivity.

    ERIC Educational Resources Information Center

    Schrag, Robert L.; And Others

    1981-01-01

    Analyzes "Taxi,""Barney Miller,""Lou Grant," and "M*A*S*H" in terms of three fantasy themes: the realization of significant others, the alliance in action, and membership into personhood. From these themes emerges a rhetorical vision of the new humane collectivity. (PD)

  20. Authentic Assessment: A Collection.

    ERIC Educational Resources Information Center

    Burke, Kay, Ed.

    The essays in this collection consider the meaning of authentic assessment and the implications of its use. "Section 1: Assessing Assessment" includes the following essays: (1) "The Nation's Report Card Goes Home: Good News and Bad about Trends in Achievement" (Robert L. Linn and Stephen B. Dunbar); (2) "Budgets, Politics, and Testing" (Chris…

  1. Deterritorializing Collective Biography

    ERIC Educational Resources Information Center

    Gannon, Susanne; Walsh, Susan; Byers, Michele; Rajiva, Mythili

    2014-01-01

    This paper proposes a new move in the methodological practice of collective biography, by provoking a shift beyond any remnant attachment to the speaking/writing subject towards her dispersal and displacement via textual interventions that stress multivocality. These include the use of photographs, drama, and various genres of writing. Using a…

  2. Collection Maintenance and Improvement.

    ERIC Educational Resources Information Center

    Byrne, Sherry

    This resource guide provides information about the range of activities that can be implemented to maintain and improve the condition of research collections to ensure that they remain usable as long as possible. After an introduction that describes the major activities and a review of an investigation process that gives an overview of good…

  3. Collection Development Policy. Revised.

    ERIC Educational Resources Information Center

    Sawin, Philip, Jr., Ed.

    This collection development policy paper incorporates guidelines contributed by all university academic departments, as well as by members of the Library Learning Center professional staff. An alphabetical index provides access to major subject areas and subdivisions, which are assigned one of four level designators indicating the depth of…

  4. Collecting My Thoughts.

    ERIC Educational Resources Information Center

    Carr, William G.

    A broad range of educational issues is treated in this collection of 120 short essays, written from the perspective of the author's 40 years in the education field. Section titles include: Teachers and Teaching; Episodes in the History of Education; Flights of Fancy; Defending the Schools; War and Peace; A Few Questions and Fewer Answers; and…

  5. Collections Define Cataloging's Future

    ERIC Educational Resources Information Center

    Simpson, Betsy

    2007-01-01

    The role of catalogers within academic libraries is evolving to meet new demands and cultivating a broader understanding of cataloging--one that focuses on collections, not the catalog, and applies cataloger expertise across metadata activities. Working collaboratively as never before, catalogers are reinventing their place within the library.

  6. Collective dynamics of sperm in viscoelastic fluid

    NASA Astrophysics Data System (ADS)

    Tung, Chih-Kuan; Harvey, Benedict B.; Fiore, Alyssa G.; Ardon, Florencia; Suarez, Susan S.; Wu, Mingming

    Collective dynamics in biology is an interesting subject for physicists, in part because of its close relations to emergent behaviors in condensed matter, such as phase separation and criticality. However, the emergence of order is often less drastic in systems composed of the living cells, sometimes due to the natural variability among individual organisms. Here, using bull sperm as a model system, we demonstrate that the cells migrate collectively in viscoelastic fluids, exhibiting behavior similar to ``flocking''. This collectiveness is greatly reduced in similarly viscous Newtonian fluids, suggesting that the cell-cell interaction is primarily a result of the elastic property or the memory effect of the fluids, instead of pure hydrodynamic interactions. Unlike bacterial swarming, this collectiveness does not require a change in phenotype of the cells; therefore, it is a better model system for physicists. Supported by NIH grant 1R01HD070038.

  7. Collective network routing

    SciTech Connect

    Hoenicke, Dirk

    2014-12-02

    Disclosed are a unified method and apparatus to classify, route, and process injected data packets into a network so as to belong to a plurality of logical networks, each implementing a specific flow of data on top of a common physical network. The method allows to locally identify collectives of packets for local processing, such as the computation of the sum, difference, maximum, minimum, or other logical operations among the identified packet collective. Packets are injected together with a class-attribute and an opcode attribute. Network routers, employing the described method, use the packet attributes to look-up the class-specific route information from a local route table, which contains the local incoming and outgoing directions as part of the specifically implemented global data flow of the particular virtual network.

  8. 78 FR 7463 - Information Collection

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-01

    ... SPACE ADMINISTRATION Information Collection AGENCY: National Aeronautics and Space Administration (NASA... to take this opportunity to comment on proposed and/or continuing information collections, as... INFORMATION CONTACT: Requests for additional information or copies of the information collection...

  9. Collecting Passion with a Purpose.

    ERIC Educational Resources Information Center

    Vandergrift, Kay E.

    1986-01-01

    Explores collecting of children's books and discusses the motivations of collectors, various levels of collecting, bibliographic tools, sources of books, collection patterns, facsimiles, and cataloging. Lists of selected bibliographic tools and selected rare book dealers are included. (EM)

  10. Collecting rare diseases

    PubMed Central

    Ekins, Sean

    2014-01-01

    This editorial introduces the F1000Research rare disease collection. It is common knowledge that for new treatments to be successful there has to be a partnership between the many interested parties such as the patient, advocate, disease foundations, the academic scientists, venture funding organizations, biotech companies, pharmaceutical companies, NIH, and the FDA. Our intention is to provide a forum for discussion and dissemination of any rare disease related topics that will advance scientific understanding and progress to treatments. PMID:25580231

  11. Wastewater Collection Systems.

    PubMed

    Vallabhaneni, Srinivas

    2016-10-01

    This chapter presents a review of the literature published in 2015 on topics relating to wastewater collection systems. It presents noteworthy advances in research and industry experiences selected from major literature sources. This review is divided into the following sections: sewer system planning; sewer condition assessment/rehabilitation; pump stations/force mains/ system design; operation and maintenance; asset management; and regulatory issues/ integrated planning. PMID:27620080

  12. Curating Virtual Data Collections

    NASA Astrophysics Data System (ADS)

    Lynnes, C.; Ramapriyan, H.; Leon, A.; Tsontos, V. M.; Liu, Z.; Shie, C. L.

    2015-12-01

    NASA's Earth Observing System Data and Information System (EOSDIS) contains a rich set of datasets and related services throughout its many elements. As a result, locating all the EOSDIS data and related resources relevant to particular science theme can be daunting. This is largely because EOSDIS data's organizing principle is affected more by the way they are produced than around the expected end use.Virtual collections oriented around science themes can overcome this by presenting collections of data and related resources that are organized around the user's interest, not around the way the data were produced. Science themes can be: Specific applications (uses) of the data, e.g., landslide prediction Geophysical events (e.g., Hurricane Sandy) A specific science research problem Virtual collections consist of annotated web addresses (URLs) that point to data and related resource addresses, thus avoiding the need to copy all of the relevant data to a single place. These URL addresses can be consumed by a variety of clients, ranging from basic URL downloaders (wget, curl) and web browsers to sophisticated data analysis programs such as the Integrated Data Viewer. Eligible resources include anything accessible via URL: data files: data file URLs data subsets: OPeNDAP, webification or Web Coverage Service URLs data visualizations: Web Map Service data search results: OpenSearch Atom response custom analysis workflows: e.g., Giovanni analysis URL

  13. Dynamic Method for Identifying Collected Sample Mass

    NASA Technical Reports Server (NTRS)

    Carson, John

    2008-01-01

    G-Sample is designed for sample collection missions to identify the presence and quantity of sample material gathered by spacecraft equipped with end effectors. The software method uses a maximum-likelihood estimator to identify the collected sample's mass based on onboard force-sensor measurements, thruster firings, and a dynamics model of the spacecraft. This makes sample mass identification a computation rather than a process requiring additional hardware. Simulation examples of G-Sample are provided for spacecraft model configurations with a sample collection device mounted on the end of an extended boom. In the absence of thrust knowledge errors, the results indicate that G-Sample can identify the amount of collected sample mass to within 10 grams (with 95-percent confidence) by using a force sensor with a noise and quantization floor of 50 micrometers. These results hold even in the presence of realistic parametric uncertainty in actual spacecraft inertia, center-of-mass offset, and first flexibility modes. Thrust profile knowledge is shown to be a dominant sensitivity for G-Sample, entering in a nearly one-to-one relationship with the final mass estimation error. This means thrust profiles should be well characterized with onboard accelerometers prior to sample collection. An overall sample-mass estimation error budget has been developed to approximate the effect of model uncertainty, sensor noise, data rate, and thrust profile error on the expected estimate of collected sample mass.

  14. 77 FR 71640 - Agency Information Collection Activities; Proposed Collection

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-03

    ... BOARD Agency Information Collection Activities; Proposed Collection AGENCY: Merit Systems Protection... a revised information collection from the Office of Management and Budget (OMB) under the Paperwork... before February 1, 2013. ADDRESSES: Submit written comments on the collection of information to William...

  15. Collective motion from local attraction.

    PubMed

    Strömbom, Daniel

    2011-08-21

    Many animal groups, for example schools of fish or flocks of birds, exhibit complex dynamic patterns while moving cohesively in the same direction. These flocking patterns have been studied using self-propelled particle models, most of which assume that collective motion arises from individuals aligning with their neighbours. Here, we propose a self-propelled particle model in which the only social force between individuals is attraction. We show that this model generates three different phases: swarms, undirected mills and moving aligned groups. By studying our model in the zero noise limit, we show how these phases depend on the relative strength of attraction and individual inertia. Moreover, by restricting the field of vision of the individuals and increasing the degree of noise in the system, we find that the groups generate both directed mills and three dynamically moving, 'rotating chain' structures. A rich diversity of patterns is generated by social attraction alone, which may provide insight into the dynamics of natural flocks. PMID:21620861

  16. Collective motion from local attraction.

    PubMed

    Strömbom, Daniel

    2011-08-21

    Many animal groups, for example schools of fish or flocks of birds, exhibit complex dynamic patterns while moving cohesively in the same direction. These flocking patterns have been studied using self-propelled particle models, most of which assume that collective motion arises from individuals aligning with their neighbours. Here, we propose a self-propelled particle model in which the only social force between individuals is attraction. We show that this model generates three different phases: swarms, undirected mills and moving aligned groups. By studying our model in the zero noise limit, we show how these phases depend on the relative strength of attraction and individual inertia. Moreover, by restricting the field of vision of the individuals and increasing the degree of noise in the system, we find that the groups generate both directed mills and three dynamically moving, 'rotating chain' structures. A rich diversity of patterns is generated by social attraction alone, which may provide insight into the dynamics of natural flocks.

  17. 76 FR 74812 - Agency Information Collection Activities: Proposed Collection; Comment Request New Collection...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-01

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF JUSTICE Office of Justice Programs Agency Information Collection Activities: Proposed Collection; Comment Request... information collection under review. The Department of Justice (DOJ), Office of Justice Programs, will...

  18. Collective Intelligence. Chapter 17

    NASA Technical Reports Server (NTRS)

    Wolpert, David H.

    2003-01-01

    Many systems of self-interested agents have an associated performance criterion that rates the dynamic behavior of the overall system. This chapter presents an introduction to the science of such systems. Formally, collectives are defined as any system having the following two characteristics: First, the system must contain one or more agents each of which we view as trying to maximize an associated private utility; second, the system must have an associated world utility function that rates the possible behaviors of that overall system. In practice, collectives are often very large, distributed, and support little, if any, centralized communication and control, although those characteristics are not part of their formal definition. A naturally occurring example of a collective is a human economy. One can identify the agents and their private utilities as the human individuals in the economy and the associated personal rewards they are each trying to maximize. One could then identify the world utility as the time average of the gross domestic product. ("World utility" per se is not a construction internal to a human economy, but rather something defined from the outside.) To achieve high world utility it is necessary to avoid having the agents work at cross-purposes lest phenomena like liquidity traps or the Tragedy of the Commons (TOC) occur, in which agents' individually pursuing their private utilities lowers world utility. The obvious way to avoid such phenomena is by modifying the agents utility functions to be "aligned" with the world utility. This can be done via punitive legislation. A real-world example of an attempt to do this was the creation of antitrust regulations designed to prevent monopolistic practices.

  19. Collective uncertainty entanglement test.

    PubMed

    Rudnicki, Łukasz; Horodecki, Paweł; Zyczkowski, Karol

    2011-10-01

    For a given pure state of a composite quantum system we analyze the product of its projections onto a set of locally orthogonal separable pure states. We derive a bound for this product analogous to the entropic uncertainty relations. For bipartite systems the bound is saturated for maximally entangled states and it allows us to construct a family of entanglement measures, we shall call collectibility. As these quantities are experimentally accessible, the approach advocated contributes to the task of experimental quantification of quantum entanglement, while for a three-qubit system it is capable to identify the genuine three-party entanglement.

  20. Collective Uncertainty Entanglement Test

    NASA Astrophysics Data System (ADS)

    Rudnicki, Łukasz; Horodecki, Paweł; Życzkowski, Karol

    2011-10-01

    For a given pure state of a composite quantum system we analyze the product of its projections onto a set of locally orthogonal separable pure states. We derive a bound for this product analogous to the entropic uncertainty relations. For bipartite systems the bound is saturated for maximally entangled states and it allows us to construct a family of entanglement measures, we shall call collectibility. As these quantities are experimentally accessible, the approach advocated contributes to the task of experimental quantification of quantum entanglement, while for a three-qubit system it is capable to identify the genuine three-party entanglement.

  1. Portable liquid collection electrostatic precipitator

    DOEpatents

    Carlson, Duane C.; DeGange, John J.; Halverson, Justin E.

    2005-10-18

    A portable liquid collection electrostatic collection precipitator for analyzing air is provided which is a relatively small, self-contained device. The device has a tubular collection electrode, a reservoir for a liquid, and a pump. The pump pumps the liquid into the collection electrode such that the liquid flows down the exterior of the collection electrode and is recirculated to the reservoir. An air intake is provided such that air to be analyzed flows through an ionization section to ionize analytes in the air, and then flows near the collection electrode where ionized analytes are collected. A portable power source is connected to the air intake and the collection electrode. Ionizable constituents in the air are ionized, attracted to the collection electrode, and precipitated in the liquid. The precipitator may also have an analyzer for the liquid and may have a transceiver allowing remote operation and data collection.

  2. Berezinskii-Kosterlitz-Thouless phase transitions in two-dimensional non-Abelian spin models.

    PubMed

    Borisenko, Oleg; Chelnokov, Volodymyr; Cuteri, Francesca; Papa, Alessandro

    2016-07-01

    It is argued that two-dimensional U(N) spin models for any N undergo a Berezinskii-Kosterlitz-Thouless (BKT)-like phase transition, similarly to the famous XY model. This conclusion follows from the Berezinskii-like calculation of the two-point correlation function in U(N) models, approximate renormalization group analysis, and numerical investigations of the U(2) model. It is shown, via Monte Carlo simulations, that the universality class of the U(2) model coincides with that of the XY model. Moreover, preliminary numerical results point out that two-dimensional SU(N) spin models with the fundamental and adjoint terms and N>4 exhibit two phase transitions of BKT type, similarly to Z(N) vector models. PMID:27575078

  3. Berezinskii-Kosterlitz-Thouless phase transitions in two-dimensional non-Abelian spin models

    NASA Astrophysics Data System (ADS)

    Borisenko, Oleg; Chelnokov, Volodymyr; Cuteri, Francesca; Papa, Alessandro

    2016-07-01

    It is argued that two-dimensional U(N ) spin models for any N undergo a Berezinskii-Kosterlitz-Thouless (BKT)-like phase transition, similarly to the famous X Y model. This conclusion follows from the Berezinskii-like calculation of the two-point correlation function in U(N ) models, approximate renormalization group analysis, and numerical investigations of the U(2 ) model. It is shown, via Monte Carlo simulations, that the universality class of the U(2 ) model coincides with that of the X Y model. Moreover, preliminary numerical results point out that two-dimensional SU(N ) spin models with the fundamental and adjoint terms and N >4 exhibit two phase transitions of BKT type, similarly to Z (N ) vector models.

  4. Collective Functionality through Bacterial Individuality

    NASA Astrophysics Data System (ADS)

    Ackermann, Martin

    According to the conventional view, the properties of an organism are a product of nature and nurture - of its genes and the environment it lives in. Recent experiments with unicellular organisms have challenged this view: several molecular mechanisms generate phenotypic variation independently of environmental signals, leading to variation in clonal groups. My presentation will focus on the causes and consequences of this microbial individuality. Using examples from bacterial genetic model systems, I will first discuss different molecular and cellular mechanisms that give rise to bacterial individuality. Then, I will discuss the consequences of individuality, and focus on how phenotypic variation in clonal populations of bacteria can promote interactions between individuals, lead to the division of labor, and allow clonal groups of bacteria to cope with environmental uncertainty. Variation between individuals thus provides clonal groups with collective functionality.

  5. Collective dynamics during cell division

    NASA Astrophysics Data System (ADS)

    Zapperi, Stefano; Bertalan, Zsolt; Budrikis, Zoe; La Porta, Caterina A. M.

    In order to correctly divide, cells have to move all their chromosomes at the center, a process known as congression. This task is performed by the combined action of molecular motors and randomly growing and shrinking microtubules. Chromosomes are captured by growing microtubules and transported by motors using the same microtubules as tracks. Coherent motion occurs as a result of a large collection of random and deterministic dynamical events. Understanding this process is important since a failure in chromosome segregation can lead to chromosomal instability one of the hallmarks of cancer. We describe this complex process in a three dimensional computational model involving thousands of microtubules. The results show that coherent and robust chromosome congression can only happen if the total number of microtubules is neither too small, nor too large. Our results allow for a coherent interpretation a variety of biological factors already associated in the past with chromosomal instability and related pathological conditions.

  6. Geoengineering as Collective Experimentation.

    PubMed

    Stilgoe, Jack

    2016-06-01

    Geoengineering is defined as the 'deliberate and large-scale intervention in the Earth's climatic system with the aim of reducing global warming'. The technological proposals for doing this are highly speculative. Research is at an early stage, but there is a strong consensus that technologies would, if realisable, have profound and surprising ramifications. Geoengineering would seem to be an archetype of technology as social experiment, blurring lines that separate research from deployment and scientific knowledge from technological artefacts. Looking into the experimental systems of geoengineering, we can see the negotiation of what is known and unknown. The paper argues that, in renegotiating such systems, we can approach a new mode of governance-collective experimentation. This has important ramifications not just for how we imagine future geoengineering technologies, but also for how we govern geoengineering experiments currently under discussion.

  7. Solar energy collection system

    NASA Technical Reports Server (NTRS)

    Miller, C. G.; Stephens, J. B. (Inventor)

    1979-01-01

    A fixed, linear, ground-based primary reflector having an extended curved sawtooth-contoured surface covered with a metalized polymeric reflecting material, reflects solar energy to a movably supported collector that is kept at the concentrated line focus reflector primary. The primary reflector may be constructed by a process utilizing well known freeway paving machinery. The solar energy absorber is preferably a fluid transporting pipe. Efficient utilization leading to high temperatures from the reflected solar energy is obtained by cylindrical shaped secondary reflectors that direct off-angle energy to the absorber pipe. A seriatim arrangement of cylindrical secondary reflector stages and spot-forming reflector stages produces a high temperature solar energy collection system of greater efficiency.

  8. Geoengineering as Collective Experimentation.

    PubMed

    Stilgoe, Jack

    2016-06-01

    Geoengineering is defined as the 'deliberate and large-scale intervention in the Earth's climatic system with the aim of reducing global warming'. The technological proposals for doing this are highly speculative. Research is at an early stage, but there is a strong consensus that technologies would, if realisable, have profound and surprising ramifications. Geoengineering would seem to be an archetype of technology as social experiment, blurring lines that separate research from deployment and scientific knowledge from technological artefacts. Looking into the experimental systems of geoengineering, we can see the negotiation of what is known and unknown. The paper argues that, in renegotiating such systems, we can approach a new mode of governance-collective experimentation. This has important ramifications not just for how we imagine future geoengineering technologies, but also for how we govern geoengineering experiments currently under discussion. PMID:25862639

  9. 78 FR 70577 - Agency Information Collection Activities; Proposed Collection, Comments Requested, New Collection...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-26

    ... Requested, New Collection: Uniform Crime Reporting Data Collection Instrument Pretesting and Burden... of the form/collection: Uniform Crime Reporting Data Collection Instrument Pretesting and Burden... have in reporting crime data to the FBI. The Paperwork Reduction Act only allows for nine...

  10. The Feasibility of Collecting School Nurse Data.

    PubMed

    Bergren, Martha Dewey

    2016-10-01

    School nurses cite barriers to collecting comprehensive data on the care they provide. This study evaluated the feasibility of collecting school nurse data on selected child health and education outcomes. Outcome variables included school health office visits; health provider, parent, and staff communication; early dismissal; and medications administered. On an average day, the school nurses cared for 43.5 students, administered 14 medications, and averaged of 17 daily communications. Day 1 data collection times averaged 15 min or less. By Day 5, 6.6 min was needed to complete the survey. Data collection was feasible for 76% of those who elected to participate. Feasibility is enhanced by limiting the number of data points and the number of days for data collection using a data collection web interface. Data collection across large numbers of nurses and a wide range of school nurse delivery models is necessary to measure the impact of school nurse presence and interventions on child health and education outcomes. PMID:27269512

  11. Collective dynamics of sperm in viscoelastic fluid

    NASA Astrophysics Data System (ADS)

    Tung, Chih-Kuan; Fiore, Alyssa G.; Ardon, Florencia; Suarez, Susan S.; Wu, Mingming

    2015-03-01

    Collective dynamics of artificial swimmers has gathered a lot of attention from physicists, in part because of its close relations to emergent behaviors in condensed matter, such as phase transitions. However, the emergence of order tends to be less drastic in the systems composed of real living cells, sometimes due to the natural variability in individual organisms. Here, using bull sperm as a model system, we demonstrate that the local orientation order of sperm spontaneously emerges in viscoelastic fluids, migrating collectively in clusters in high cell concentrations, or pairs in low cell concentrations. This collectiveness is similar to a liquid-gas phase transition, as both phases coexist simultaneously in our system. Unlike bacterial swarming, this collectiveness does not require the cells to be in a different phenotype than the regular swimming one, providing further simplicity to the physicists. We will discuss the underlying interaction mechanism, and the potential influence in biology. Supported by NIH Grant 1R01HD070038.

  12. 78 FR 28848 - Information Collection Activities; Proposed Collection; Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-16

    ... for Healthcare Research and Quality's (AHRQ) Hospital Survey on Patient Safety Culture Comparative... HUMAN SERVICES Agency for Healthcare Research and Quality Agency Information Collection Activities; Proposed Collection; Comment Request AGENCY: Agency for Healthcare Research and Quality, HHS....

  13. Collective and non-collective structures in nuclei of mass region A ≈ 125

    SciTech Connect

    Singh, A. K.; Collaboration: INGA Collaboration; Gammasphere Collaboration

    2014-08-14

    Generation of angular momentum in nuclei is a key question in nuclear structure studies. In single particle model, it is due to alignment of spin of individual nucleon available in the valence space, whereas coherent motion of nucleons are assumed in the collective model. The nuclei near the closed shell at Z = 50 with mass number A ≈ 120-125 represent ideal cases to explore the interplay between these competing mechanisms and the transition from non-collective to collective behavior or vice versa. Recent spectroscopic studies of nuclei in this region reveal several non-collective maximally aligned states representing the first kind of excitation mechanism, where 8-12 particles above the {sup 114}Sn align their spins to generate these states. Deformed rotational bands feeding the non-collective states in the spin range I=20-25 and excitation energies around 10 MeV have also been observed. Structure of the collective and non-collective states are discussed in the framework of Cranked-Nilsson-Strutinsky model.

  14. Forecasting Zakat collection using artificial neural network

    NASA Astrophysics Data System (ADS)

    Sy Ahmad Ubaidillah, Sh. Hafizah; Sallehuddin, Roselina

    2013-04-01

    'Zakat', "that which purifies" or "alms", is the giving of a fixed portion of one's wealth to charity, generally to the poor and needy. It is one of the five pillars of Islam, and must be paid by all practicing Muslims who have the financial means (nisab). 'Nisab' is the minimum level to determine whether there is a 'zakat' to be paid on the assets. Today, in most Muslim countries, 'zakat' is collected through a decentralized and voluntary system. Under this voluntary system, 'zakat' committees are established, which are tasked with the collection and distribution of 'zakat' funds. 'Zakat' promotes a more equitable redistribution of wealth, and fosters a sense of solidarity amongst members of the 'Ummah'. The Malaysian government has established a 'zakat' center at every state to facilitate the management of 'zakat'. The center has to have a good 'zakat' management system to effectively execute its functions especially in the collection and distribution of 'zakat'. Therefore, a good forecasting model is needed. The purpose of this study is to develop a forecasting model for Pusat Zakat Pahang (PZP) to predict the total amount of collection from 'zakat' of assets more precisely. In this study, two different Artificial Neural Network (ANN) models using two different learning algorithms are developed; Back Propagation (BP) and Levenberg-Marquardt (LM). Both models are developed and compared in terms of their accuracy performance. The best model is determined based on the lowest mean square error and the highest correlations values. Based on the results obtained from the study, BP neural network is recommended as the forecasting model to forecast the collection from 'zakat' of assets for PZP.

  15. 76 FR 30949 - Agency Information Collection Activities: Proposed Collection: Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-27

    ... components: a. Design and implementation of a forecasting model to estimate and project the supply of and... collect the information needed to develop HIV-specific input parameters for the forecasting model, as well... characteristics of HIV patient load; d. The primary practice characteristics and patient management...

  16. Swarms, phase transitions, and collective intelligence

    SciTech Connect

    Millonas, M.M.

    1992-12-31

    A model of the collective behavior of a large number of locally acting organisms is proposed. The model is intended to be realistic, but turns out to fit naturally into the category of connectionist models, Like all connectionist models, its properties can be divided into the categories of structure, dynamics, and learning. The space in which the organisms move is discretized, and is modeled by a lattice of nodes, or cells. Each cell hag a specified volume, and is connected to other cells in the space in a definite way. Organisms move probabilistically between local cells in this space, but with weights dependent on local morphogenic substances, or morphogens. The morphogens are in turn are effected by the passage of an organism. The evolution of the morphogens, and the corresponding constitutes of the organisms constitutes the collective behavior of the group. The generic properties of such systems are analyzed, and a number of results are obtained. The model has various types of phase transitions and self-organizing properties controlled both by the level of the noise, and other parameters. It is hoped that the present mode; might serve as a paradigmatic example of a complex cooperative system in nature. In particular this model can be used to explore the relation of phase transitions to at least three important issues encountered in artificial life. Firstly, that of emergence as complex adaptive behavior. Secondly, as an exploration of second order phase transitions in biological systems. Lastly, to derive behavioral criteria for the evolution of collective behavior in social organisms. The model is then applied to the specific case of ants moving on a lattice. The local behavior of the ants is inspired by the actual behavior observed in the laboratory, and analytic results for the collective behavior are compared to the corresponding laboratory results. Monte carlo simulations are used as illustrations.

  17. Swarms, phase transitions, and collective intelligence

    SciTech Connect

    Millonas, M.M. . Dept. of Physics)

    1992-01-01

    A model of the collective behavior of a large number of locally acting organisms is proposed. The model is intended to be realistic, but turns out to fit naturally into the category of connectionist models, Like all connectionist models, its properties can be divided into the categories of structure, dynamics, and learning. The space in which the organisms move is discretized, and is modeled by a lattice of nodes, or cells. Each cell hag a specified volume, and is connected to other cells in the space in a definite way. Organisms move probabilistically between local cells in this space, but with weights dependent on local morphogenic substances, or morphogens. The morphogens are in turn are effected by the passage of an organism. The evolution of the morphogens, and the corresponding constitutes of the organisms constitutes the collective behavior of the group. The generic properties of such systems are analyzed, and a number of results are obtained. The model has various types of phase transitions and self-organizing properties controlled both by the level of the noise, and other parameters. It is hoped that the present mode; might serve as a paradigmatic example of a complex cooperative system in nature. In particular this model can be used to explore the relation of phase transitions to at least three important issues encountered in artificial life. Firstly, that of emergence as complex adaptive behavior. Secondly, as an exploration of second order phase transitions in biological systems. Lastly, to derive behavioral criteria for the evolution of collective behavior in social organisms. The model is then applied to the specific case of ants moving on a lattice. The local behavior of the ants is inspired by the actual behavior observed in the laboratory, and analytic results for the collective behavior are compared to the corresponding laboratory results. Monte carlo simulations are used as illustrations.

  18. Collective Wisdom, Clones, and New Creations.

    ERIC Educational Resources Information Center

    Villadsen, Alice W.

    2002-01-01

    Concerned with the impending community college leadership deficit, the author articulates a vision for reinventing leadership development programs that balance the collective wisdom of experience with the innovation essential for addressing the cultural and technological challenges of the future. Presents three model leadership programs that…

  19. The Collective Bargaining Mystery: Some New Clues.

    ERIC Educational Resources Information Center

    Mazzarella, Jo Ann

    1984-01-01

    Recent studies at the Center for Educational Policy and Management provide insight into how collective bargaining affects the teaching profession, educational policy, and student achievement. Charles Kerchner's report links a three-stage labor relations model with an analysis of teaching as work. His case studies, besides revealing wide variations…

  20. Emerging Trends in Faculty Collective Bargaining Agreements.

    ERIC Educational Resources Information Center

    Andes, John O.; Goodwin, Harold I.

    1972-01-01

    Major trends revealed from an analysis of 46 collective bargaining agreements are discussed. The most obvious trend involves the agent with whom college faculty affiliate, with the National Education Association and the American Federation of Teachers dominating. It is shown that the bargaining model developing in higher education is closely…

  1. Designing a Collection Development Plan for Sailor.

    ERIC Educational Resources Information Center

    Davis, Denise M.

    1996-01-01

    Sailor, Maryland's public information network, has become a national model for public libraries and states planning telecommunications networks and library systems integration. This article summarizes the design and implementation of the network's Internet resource collection development, highlighting the database committee, editorial board,…

  2. 78 FR 51170 - Proposed Collection; Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-20

    ... obtain a copy of the proposal and associated collection instruments, please write to Defense Threat..., biological, radiological and nuclear modeling and simulation tools used by Federally Funded Academic Research... very narrow customer base composed of Federally Funded Academic Research and Development,...

  3. Power, Collective Bargaining, and School Governance.

    ERIC Educational Resources Information Center

    Cresswell, Anthony M.

    1980-01-01

    Claims there are many styles of governance observable in schools and that these are a consequence of changes in schooling technology and in shifting demands from school environments. Asserts that an understanding of school governance and the place of collective bargaining within it requires sensitivity to the multiple mental models. (Author/MK)

  4. Collective decision making in cohesive flocks

    NASA Astrophysics Data System (ADS)

    Bhattacharya, K.; Vicsek, Tamás

    2010-09-01

    Most of us must have been fascinated by the eye-catching displays of collectively moving animals. Schools of fish can move in a rather orderly fashion and then change direction amazingly abruptly. There are a large number of further examples both from the living and the non-living world for phenomena during which the many interacting, permanently moving units seem to arrive at a common behavioural pattern taking place in a short time. As a paradigm of this type of phenomena we consider the problem of how birds arrive at a decision resulting in their synchronized landing. We introduce a simple model to interpret this process. Collective motion prior to landing is modelled using a simple self-propelled particle (SPP) system with a new kind of boundary condition, while the tendency and the sudden propagation of the intention of landing are introduced through rules analogous to the random field Ising model in an external field. We show that our approach is capable of capturing the most relevant features of collective decision making in a system of units with variance of individual intentions and being under an increasing level of pressure to switch states. We find that as a function of the few parameters of our model the collective switching from the flying to the landing state is indeed much sharper than the distribution of individual landing intentions. The transition is accompanied by a number of interesting features discussed in this paper.

  5. Waste collection subsystem study

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Practical ways were explored of improving waste compaction and of providing rapid turnaround between flights at essentially no cost for the space shuttle waste collection subsystem commode. Because of the possible application of a fully developed shuttle commode to the space station, means of providing waste treatment without overboard venting were also considered. Three basic schemes for compaction and rapid turnaround, each fully capable of meeting the objectives, were explored in sufficient depth to bring out the characteristic advantages and disadvantages of each. Tradeoff comparisons were very close between leading contenders and efforts were made to refine the design concepts sufficiently to justify a selection. The concept selected makes use of a sealed canister containing wastes that have been forcibly compacted, which is removable in flight. No selection was made between three superior non-venting treatment methods owing to the need for experimental evaluations of the processes involved. A system requirements definition document has been prepared to define the task for a test embodiment of the selected concept.

  6. Collective dynamics of social annotation.

    PubMed

    Cattuto, Ciro; Barrat, Alain; Baldassarri, Andrea; Schehr, Gregory; Loreto, Vittorio

    2009-06-30

    The enormous increase of popularity and use of the worldwide web has led in the recent years to important changes in the ways people communicate. An interesting example of this fact is provided by the now very popular social annotation systems, through which users annotate resources (such as web pages or digital photographs) with keywords known as "tags." Understanding the rich emergent structures resulting from the uncoordinated actions of users calls for an interdisciplinary effort. In particular concepts borrowed from statistical physics, such as random walks (RWs), and complex networks theory, can effectively contribute to the mathematical modeling of social annotation systems. Here, we show that the process of social annotation can be seen as a collective but uncoordinated exploration of an underlying semantic space, pictured as a graph, through a series of RWs. This modeling framework reproduces several aspects, thus far unexplained, of social annotation, among which are the peculiar growth of the size of the vocabulary used by the community and its complex network structure that represents an externalization of semantic structures grounded in cognition and that are typically hard to access. PMID:19506244

  7. Collective decisions among bacterial viruses

    NASA Astrophysics Data System (ADS)

    Joh, Richard; Mileyko, Yuriy; Voit, Eberhard; Weitz, Joshua

    2010-03-01

    For many temperate bacteriophages, the decision of whether to kill hosts or enter a latent state depends on the multiplicity of infection. In this talk, I present a quantitative model of gene regulatory dynamics to describe how phages make collective decisions within host cells. Unlike most previous studies, the copy number of viral genomes is treated as a variable. In the absence of feedback loops, viral mRNA transcription is expected to be proportional to the viral copy number. However, when there are nonlinear feedback loops in viral gene regulation, our model shows that gene expression patterns are sensitive to changes in viral copy number and there can be a domain of copy number where the system becomes bistable. Hence, the viral copy number is a key control parameter determining host cell fates. This suggests that bacterial viruses can respond adaptively to changes in population dynamics, and can make alternative decisions as a bet-hedging strategy. Finally, I present a stochastic version of viral gene regulation and discuss speed-accuracy trade-offs in the context of cell fate determination by viruses.

  8. Collection Development Policy: Government Information.

    ERIC Educational Resources Information Center

    Blazek, Dan

    Intended as a general guideline for selecting government documents at the University of Miami (Florida) Otto G. Richter Library, this collection development policy includes the following sections: (1) Introduction; (2) Mission Statement; (3) Selection Responsibility; (4) Subject Areas, Collection Intensity Levels and Collection Arrangement,…

  9. The ARL Special Collections Initiative.

    ERIC Educational Resources Information Center

    Hewitt, Joe A.; Panitch, Judith M.

    2003-01-01

    Reviews the Association of Research Libraries (ARL) activities regarding special collections. Highlights include local and collaborative approaches; budget pressures; access to special collections; digitization programs; recruiting qualified staff; results of a survey of ARL special collections; and the need for ongoing statistics for special…

  10. Houston Cole Library Collection Assessment.

    ERIC Educational Resources Information Center

    Henderson, William Abbot, Ed.; McAbee, Sonja L., Ed.

    This document reports on an assessment of the Jacksonville State University's Houston Cole Library collection that employed a variety of methodologies and tools, including list-checking, direct collection examination, shelflist measurement and analysis, WLN (Washington Library Network) conspectus sheets, analysis of OCLC/AMIGOS Collection Analysis…

  11. 75 FR 42662 - Debt Collection

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-22

    ... FCCS. 65 FR 70390 (Nov. 20, 2000). Overview of Proposed Regulatory Changes This proposed regulation... to PBGC by various individuals, PBGC-13, Debt Collection. See 65 FR 25397 (May 1, 2000). Subpart A... promote aggressive debt collection, using for each debt all available and appropriate collection...

  12. Managing University Research Microdata Collections

    ERIC Educational Resources Information Center

    Woolfrey, Lynn; Fry, Jane

    2015-01-01

    This article examines the management of microdata collections in a university context. It is a cross-country analysis: Collection management at data services in Canada and South Africa are considered. The case studies are of two university sub-contexts: One collection is located in a library; the other at a Faculty-based Data Service. Stages in…

  13. Gesammelte Werke / Collected Works

    NASA Astrophysics Data System (ADS)

    Schwarzschild, Karl; Voigt, Hans-Heinrich

    Der bekannte Astronom Karl Schwarzschild (1873-1916) gilt als der Begründer der Astrophysik und als hervorragender Forscher mit einer erstaunlichen Bandbreite seiner Interessen. Arbeiten zur Himmelsmechanik, Elektrodynamik und Relativitätstheorie weisen ihn als vorzüglichen Mathematiker und Physiker auf der Höhe seiner Zeit aus. Untersuchungen zur Photographischen Photometrie, Optik und Spektroskopie zeigen den versierten Beobachter, der sein Meßinstrumentarium beherrscht, und schließlich arbeitete Schwarzschild als Astrophysiker an Sternatmosphären, Kometen, Struktur und Dynamik von Sternsystemen. Die in seinem kurzen Leben entstandene Fülle an wissenschaftlichen Arbeiten ist in drei Bänden der Gesamtausgabe gesammelt, ergänzt durch biographisches Material, Annotationen von Fachleuten und einen Essay des Nobelpreisträgers S. Chandrasekhar. The well-known astronomer Karl Schwarzschild (1873-1916) is regarded as the founder of astrophysics and as an exceptionally talented researcher whose interests spanned a remarkably broad spectrum. His work on celestial mechanics, electrodynamics, and relativity theory demonstrates his great abilities as a mathematician and physicist who significantly influenced the science of his times. His investigations of photographic photometry, optics, and spectroscopy display his strengths as an observer who knew his instruments. But above all Schwarzschild pursued questions of astrophysics, addressing in particular stellar atmospheres, comets, and the structure and dynamics of stellar systems. The host of scientific works that he authored in his short life is now collected in the form of this three-volume complete works; it is supplemented by biographical material, notes from some of todays experts, and an essay by the Nobel Laureate S. Chandrasekhar.

  14. Physician collective bargaining.

    PubMed

    Schiff, Anthony Hunter

    2009-11-01

    Current antitrust enforcement policy unduly restricts physician collaboration, especially among small physician practices. Among other matters, current enforcement policy has hindered the ability of physicians to implement efficient healthcare delivery innovations, such as the acquisition and implementation of health information technology (HIT). Furthermore, the Federal Trade Commission and Department of Justice have unevenly enforced the antitrust laws, thereby fostering an increasingly severe imbalance in the healthcare market in which dominant health insurers enjoy the benefit of largely unfettered consolidation at the cost of both consumers and providers. This article traces the history of antitrust enforcement in healthcare, describe the current marketplace, and suggest the problems that must be addressed to restore balance to the healthcare market and help to ensure an innovative and efficient healthcare system capable of meeting the demands of the 21st century. Specifically, the writer explains how innovative physician collaborations have been improperly stifled by the policies of the federal antitrust enforcement agencies, and recommend that these policies be relaxed to permit physicians more latitude to bargain collectively with health insurers in conjunction with procompetitive clinical integration efforts. The article also explains how the unbridled consolidation of the health insurance industry has resulted in higher premiums to consumers and lower compensation to physicians, and recommends that further consolidation be prohibited. Finally, the writer discusses how health insurers with market power are improperly undermining the physician-patient relationship, and recommend federal antitrust enforcement agencies take appropriate steps to protect patients and their physicians from this anticompetitive conduct. The article also suggests such steps will require changes in three areas: (1) health insurers must be prohibited from engaging in anticompetitive

  15. Collective motion in animal groups

    NASA Astrophysics Data System (ADS)

    Couzin, Iain

    2004-03-01

    In recent years there has been a growing interest in the relationship between individual behavior and population-level properties in animal groups. One of the fundamental problems is related to spatial scale; how do interactions over a local range result in population properties at larger, averaged, scales, and how can we integrate the properties of aggregates over these scales? Many group-living animals exhibit complex, and coordinated, spatio-temporal patterns which despite their ubiquity and ecological importance are very poorly understood. This is largely due to the difficulties associated with quantifying the motion of, and interactions among, many animals simultaneously. It is on how these behaviors scale to collective behaviors that I will focus here. Using a combined empirical approach (using novel computer vision techniques) and individual-based computer models, I investigate pattern formation in both invertebrate and vertebrate systems, including - Collective memory and self-organized group structure in vertebrate groups (Couzin, I.D., Krause, J., James, R., Ruxton, G.D. & Franks, N.R. (2002) Journal of Theoretical Biology 218, 1-11. (2) Couzin, I.D. & Krause, J. (2003) Advances in the Study of Behavior 32, 1-75. (3) Hoare, D.J., Couzin, I.D. Godin, J.-G. & Krause, J. (2003) Animal Behaviour, in press.) - Self-organized lane formation and optimized traffic flow in army ants (Couzin, I.D. & Franks, N.R. (2003) Proceedings of the Royal Society of London, Series B 270, 139-146) - Leadership and information transfer in flocks, schools and swarms. - Why do hoppers hop? Hopping and the generation of long-range order in some of the largest animal groups in nature, locust hopper bands.

  16. Loftin Collection - Boeing Aircraft

    NASA Technical Reports Server (NTRS)

    1933-01-01

    Either a F2B-1 or F3B-1, both aircraft were built by Boeing and both were powered by Pratt and Whitney Wasp engines. These fighters were intended for Navy shipboard use. Boeing F3B-1: While most Boeing F3B-1s served the U. S. Navy aircraft carriers the Lexington and the Saratoga, this example flew in NACA hands at the Langley Memorial Aeronautical Laboratory in the late 1920's. Also known as the Boeing Model 77, the aircraft was the next to last F3B-1 build in November 1928.

  17. Study of data collection platform concepts: Data collection system user requirements

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The overall purpose of the survey was to provide real world data on user requirements. The intent was to assess data collection system user requirements by questioning actual potential users rather than speculating on requirements. The end results of the survey are baseline requirements models for both a data collection platform and a data collection system. These models were derived from the survey results. The real value of these models lies in the fact that they are based on actual user requirements as delineated in the survey questionnaires. Some users desire data collection platforms of small size and light weight. These sizes and weights are beyond the present state of the art. Also, the survey provided a wealth of information on the nature and constituency of the data collection user community as well as information on user applications for data collection systems. Finally, the data sheds light on the generalized platform concept. That is, the diversity of user requirements shown in the data indicates the difficulty that can be anticipated in attempting to implement such a concept.

  18. Emergence of oligarchy in collective cell migration

    NASA Astrophysics Data System (ADS)

    Schumacher, Linus; Maini, Philip; Baker, Ruth

    Identifying the principles of collective cell migration has the potential to help prevent birth defects, improve regenerative therapies and develop model systems for cancer metastasis. In collaboration with experimental biologists, we use computational simulations of a hybrid model, comprising individual-based stochastic cell movement coupled to a reaction-diffusion equation for a chemoattractant, to explore the role of cell specialisation in the guidance of collective cell migration. In the neural crest, an important migratory cell population in vertebrate embryo development, we present evidence that just a few cells are guiding group migration in a cell-induced chemoattractant gradient that determines the switch between ``leader'' and ``follower'' behaviour in individual cells. This leads us to more generally consider under what conditions cell specialisation might become advantageous for collective migration. Alternatively, individual cell responses to locally different microenvironmental conditions could create the (artefactual) appearance of heterogeneity in a population of otherwise identical cellular agents. We explore these questions using a self-propelled particle model as a minimal description for collective cell migration in two and three dimensions.

  19. Introduction to the Rosetta Special Collection

    PubMed Central

    Khare, Sagar D.; Whitehead, Timothy A.

    2015-01-01

    The Rosetta macromolecular modeling software is a versatile, rapidly developing set of tools that are now being routinely utilized to address state-of-the-art research challenges in academia and industrial research settings. A Rosetta Conference (RosettaCon) describing updates to the Rosetta source code is held annually. Every two years, a Rosetta Conference (RosettaCon) special collection describing the results presented at the annual conference by participating RosettaCommons labs is published by the Public Library of Science (PLOS). This is the introduction to the third RosettaCon 2014 Special Collection published by PLOS. PMID:26714017

  20. 77 FR 6573 - Agency Information Collection Activities: Proposed Collection; Comment Request; Collection of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-08

    ... SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Proposed Collection; Comment Request; Collection of Qualitative Feedback Through Focus Groups AGENCY: U.S. Citizenship... Department of Homeland Security, U.S. Citizenship and Immigration Services (USCIS) will be submitting...