WorldWideScience

Sample records for model successfully describes

  1. Successful modeling?

    Science.gov (United States)

    Lomnitz, Cinna

    Tichelaar and Ruff [1989] propose to “estimate model variance in complicated geophysical problems,” including the determination of focal depth in earthquakes, by means of unconventional statistical methods such as bootstrapping. They are successful insofar as they are able to duplicate the results from more conventional procedures.

  2. Frameworks for understanding and describing business models

    DEFF Research Database (Denmark)

    Nielsen, Christian; Roslender, Robin

    2014-01-01

    This chapter provides in a chronological fashion an introduction to six frameworks that one can apply to describing, understanding and also potentially innovating business models. These six frameworks have been chosen carefully as they represent six very different perspectives on business models...... and in this manner “complement” each other. There are a multitude of varying frameworks that could be chosen from and we urge the reader to search and trial these for themselves. The six chosen models (year of release in parenthesis) are: • Service-Profit Chain (1994) • Strategic Systems Auditing (1997) • Strategy...... Maps (2001) • Intellectual Capital Statements (2003) • Chesbrough’s framework for Open Business Models (2006) • Business Model Canvas (2008)...

  3. Inhomogeneous Markov Models for Describing Driving Patterns

    DEFF Research Database (Denmark)

    Iversen, Emil Banning; Møller, Jan K.; Morales, Juan Miguel

    2017-01-01

    . Specifically, an inhomogeneous Markov model that captures the diurnal variation in the use of a vehicle is presented. The model is defined by the time-varying probabilities of starting and ending a trip, and is justified due to the uncertainty associated with the use of the vehicle. The model is fitted to data...... collected from the actual utilization of a vehicle. Inhomogeneous Markov models imply a large number of parameters. The number of parameters in the proposed model is reduced using B-splines....

  4. Inhomogeneous Markov Models for Describing Driving Patterns

    DEFF Research Database (Denmark)

    Iversen, Jan Emil Banning; Møller, Jan Kloppenborg; Morales González, Juan Miguel

    . Specically, an inhomogeneous Markov model that captures the diurnal variation in the use of a vehicle is presented. The model is dened by the time-varying probabilities of starting and ending a trip and is justied due to the uncertainty associated with the use of the vehicle. The model is tted to data...... collected from the actual utilization of a vehicle. Inhomogeneous Markov models imply a large number of parameters. The number of parameters in the proposed model is reduced using B-splines....

  5. Using Metaphorical Models for Describing Glaciers

    Science.gov (United States)

    Felzmann, Dirk

    2014-01-01

    To date, there has only been little conceptual change research regarding conceptions about glaciers. This study used the theoretical background of embodied cognition to reconstruct different metaphorical concepts with respect to the structure of a glacier. Applying the Model of Educational Reconstruction, the conceptions of students and scientists…

  6. Modeling Approaches for Describing Microbial Population Heterogeneity

    DEFF Research Database (Denmark)

    Lencastre Fernandes, Rita

    environmental conditions. Three cases are presented and discussed in this thesis. Common to all is the use of S. cerevisiae as model organism, and the use of cell size and cell cycle position as single-cell descriptors. The first case focuses on the experimental and mathematical description of a yeast...

  7. Using the MWC model to describe heterotropic interactions in hemoglobin

    Science.gov (United States)

    Rapp, Olga

    2017-01-01

    Hemoglobin is a classical model allosteric protein. Research on hemoglobin parallels the development of key cooperativity and allostery concepts, such as the ‘all-or-none’ Hill formalism, the stepwise Adair binding formulation and the concerted Monod-Wymann-Changuex (MWC) allosteric model. While it is clear that the MWC model adequately describes the cooperative binding of oxygen to hemoglobin, rationalizing the effects of H+, CO2 or organophosphate ligands on hemoglobin-oxygen saturation using the same model remains controversial. According to the MWC model, allosteric ligands exert their effect on protein function by modulating the quaternary conformational transition of the protein. However, data fitting analysis of hemoglobin oxygen saturation curves in the presence or absence of inhibitory ligands persistently revealed effects on both relative oxygen affinity (c) and conformational changes (L), elementary MWC parameters. The recent realization that data fitting analysis using the traditional MWC model equation may not provide reliable estimates for L and c thus calls for a re-examination of previous data using alternative fitting strategies. In the current manuscript, we present two simple strategies for obtaining reliable estimates for MWC mechanistic parameters of hemoglobin steady-state saturation curves in cases of both evolutionary and physiological variations. Our results suggest that the simple MWC model provides a reasonable description that can also account for heterotropic interactions in hemoglobin. The results, moreover, offer a general roadmap for successful data fitting analysis using the MWC model. PMID:28793329

  8. HERMES: A Model to Describe Deformation, Burning, Explosion, and Detonation

    Energy Technology Data Exchange (ETDEWEB)

    Reaugh, J E

    2011-11-22

    pressure that results from a more gradual increase. This disagrees with experiments, where explosives were subjected to a gradual rise in pressure and did not exhibit reaction. More recent models do distinguish between slow pressure rises and shocks, and have had some success in the describing the response of explosives to single and multiple shocks, and the increase of shock sensitivity with porosity, at least over a limited range. The original formulation is appropriate for sustained shocks, but further work is ongoing to describe the response to short pulses. The HERMES model combines features from these prior models. It describes burning and explosion in damaged reactant, and also will develop a detonation if the gradual rise in pressure from burning steepens into a strong-enough shock. The shock strength needed for detonation in a fixed run distance decreases with increasing porosity.

  9. Model checking biological systems described using ambient calculus

    DEFF Research Database (Denmark)

    Mardare, Radu Iulian; Priami, Corrado; Qualia, Paola

    2005-01-01

    Model checking biological systems described using ambient calculus. In Proc. of the second International Workshop on Computational Methods in Systems Biology (CMSB04), Lecture Notes in Bioinformatics 3082:85-103, Springer, 2005.......Model checking biological systems described using ambient calculus. In Proc. of the second International Workshop on Computational Methods in Systems Biology (CMSB04), Lecture Notes in Bioinformatics 3082:85-103, Springer, 2005....

  10. Statistical models describing the energy signature of buildings

    DEFF Research Database (Denmark)

    Bacher, Peder; Madsen, Henrik; Thavlov, Anders

    2010-01-01

    Approximately one third of the primary energy production in Denmark is used for heating in buildings. Therefore efforts to accurately describe and improve energy performance of the building mass are very important. For this purpose statistical models describing the energy signature of a building, i...... or varying energy prices. The paper will give an overview of statistical methods and applied models based on experiments carried out in FlexHouse, which is an experimental building in SYSLAB, Risø DTU. The models are of different complexity and can provide estimates of physical quantities such as UA......-values, time constants of the building, and other parameters related to the heat dynamics. A method for selecting the most appropriate model for a given building is outlined and finally a perspective of the applications is given. Aknowledgements to the Danish Energy Saving Trust and the Interreg IV ``Vind i...

  11. Models for describing the thermal characteristics of building components

    DEFF Research Database (Denmark)

    Jimenez, M.J.; Madsen, Henrik

    2008-01-01

    , for example. For the analysis of these tests, dynamic analysis models and methods are required. However, a wide variety of models and methods exists, and the problem of choosing the most appropriate approach for each particular case is a non-trivial and interdisciplinary task. Knowledge of a large family....... The characteristics of each type of model are highlighted. Some available software tools for each of the methods described will be mentioned. A case study also demonstrating the difference between linear and nonlinear models is considered....... of these approaches may therefore be very useful for selecting a suitable approach for each particular case. This paper presents an overview of models that can be applied for modelling the thermal characteristics of buildings and building components using data from outdoor testing. The choice of approach depends...

  12. Icosahedral symmetry described by an incommensurately modulated crystal structure model

    DEFF Research Database (Denmark)

    Wolny, Janusz; Lebech, Bente

    1986-01-01

    A crystal structure model of an incommensurately modulated structure is presented. Although six different reciprocal vectors are used to describe the model, all calculations are done in three dimensions making calculation of the real-space structure trivial. Using this model, it is shown that both...... the positions of the bragg reflections and information about the relative intensities of these reflections are in full accordance with the diffraction patterns reported for microcrystals of the rapidly quenched Al86Mn14 alloy. It is also shown that at least the local structure possesses full icosahedral...

  13. A Model Describing Stable Coherent Synchrotron Radiation in Storage Rings

    International Nuclear Information System (INIS)

    Sannibale, F.

    2004-01-01

    We present a model describing high power stable broadband coherent synchrotron radiation (CSR) in the terahertz frequency region in an electron storage ring. The model includes distortion of bunch shape from the synchrotron radiation (SR), which enhances higher frequency coherent emission, and limits to stable emission due to an instability excited by the SR wakefield. It gives a quantitative explanation of several features of the recent observations of CSR at the BESSY II storage ring. We also use this model to optimize the performance of a source for stable CSR emission

  14. A model describing stable coherent synchrotron radiation in storage rings

    International Nuclear Information System (INIS)

    Sannibale, F.; Byrd, J.M.; Loftsdottir, A.; Venturini, M.; Abo-Bakr, M.; Feikes, J.; Holldack, K.; Kuske, P.; Wuestefeld, G.; Huebers, H.-W.; Warnock, R.

    2004-01-01

    We present a model describing high power stable broadband coherent synchrotron radiation (CSR) in the terahertz frequency region in an electron storage ring. The model includes distortion of bunch shape from the synchrotron radiation (SR), which enhances higher frequency coherent emission, and limits to stable emission due to an instability excited by the SR wakefield. It gives a quantitative explanation of several features of the recent observations of CSR at the BESSY II storage ring. We also use this model to optimize the performance of a source for stable CSR emission

  15. A Kinetic Model Describing Injury-Burden in Team Sports.

    Science.gov (United States)

    Fuller, Colin W

    2017-12-01

    Injuries in team sports are normally characterised by the incidence, severity, and location and type of injuries sustained: these measures, however, do not provide an insight into the variable injury-burden experienced during a season. Injury burden varies according to the team's match and training loads, the rate at which injuries are sustained and the time taken for these injuries to resolve. At the present time, this time-based variation of injury burden has not been modelled. To develop a kinetic model describing the time-based injury burden experienced by teams in elite team sports and to demonstrate the model's utility. Rates of injury were quantified using a large eight-season database of rugby injuries (5253) and exposure (60,085 player-match-hours) in English professional rugby. Rates of recovery from injury were quantified using time-to-recovery analysis of the injuries. The kinetic model proposed for predicting a team's time-based injury burden is based on a composite rate equation developed from the incidence of injury, a first-order rate of recovery from injury and the team's playing load. The utility of the model was demonstrated by examining common scenarios encountered in elite rugby. The kinetic model developed describes and predicts the variable injury-burden arising from match play during a season of rugby union based on the incidence of match injuries, the rate of recovery from injury and the playing load. The model is equally applicable to other team sports and other scenarios.

  16. A model to describe the performance of the UASB reactor.

    Science.gov (United States)

    Rodríguez-Gómez, Raúl; Renman, Gunno; Moreno, Luis; Liu, Longcheng

    2014-04-01

    A dynamic model to describe the performance of the Upflow Anaerobic Sludge Blanket (UASB) reactor was developed. It includes dispersion, advection, and reaction terms, as well as the resistances through which the substrate passes before its biotransformation. The UASB reactor is viewed as several continuous stirred tank reactors connected in series. The good agreement between experimental and simulated results shows that the model is able to predict the performance of the UASB reactor (i.e. substrate concentration, biomass concentration, granule size, and height of the sludge bed).

  17. Conceptual hierarchical modeling to describe wetland plant community organization

    Science.gov (United States)

    Little, A.M.; Guntenspergen, G.R.; Allen, T.F.H.

    2010-01-01

    Using multivariate analysis, we created a hierarchical modeling process that describes how differently-scaled environmental factors interact to affect wetland-scale plant community organization in a system of small, isolated wetlands on Mount Desert Island, Maine. We followed the procedure: 1) delineate wetland groups using cluster analysis, 2) identify differently scaled environmental gradients using non-metric multidimensional scaling, 3) order gradient hierarchical levels according to spatiotem-poral scale of fluctuation, and 4) assemble hierarchical model using group relationships with ordination axes and post-hoc tests of environmental differences. Using this process, we determined 1) large wetland size and poor surface water chemistry led to the development of shrub fen wetland vegetation, 2) Sphagnum and water chemistry differences affected fen vs. marsh / sedge meadows status within small wetlands, and 3) small-scale hydrologic differences explained transitions between forested vs. non-forested and marsh vs. sedge meadow vegetation. This hierarchical modeling process can help explain how upper level contextual processes constrain biotic community response to lower-level environmental changes. It creates models with more nuanced spatiotemporal complexity than classification and regression tree procedures. Using this process, wetland scientists will be able to generate more generalizable theories of plant community organization, and useful management models. ?? Society of Wetland Scientists 2009.

  18. Can the "standard" unitarized Regge models describe the TOTEM data?

    CERN Document Server

    Alkin, A; Martynov, E

    2013-01-01

    The standard Regge poles are considered as inputs for two unitarization methods: eikonal and U-matrix. It is shown that only models with three input pomerons and two input odderons can describe the high energy data on $pp$ and $\\bar pp$ elastic scattering including the new data from Tevatron and LHC. However, it seems that the both considered models require a further modification (e.g. nonlinear reggeon trajectories and/or nonexponential vertex functions) for a more satisfactory description of the data at 19.0 GeV$\\leq \\sqrt{s}\\leq$ 7 TeV and 0.01 $\\leq |t|\\leq $14.2 GeV$^{2}$.

  19. Experimental investigation of statistical models describing distribution of counts

    International Nuclear Information System (INIS)

    Salma, I.; Zemplen-Papp, E.

    1992-01-01

    The binomial, Poisson and modified Poisson models which are used for describing the statistical nature of the distribution of counts are compared theoretically, and conclusions for application are considered. The validity of the Poisson and the modified Poisson statistical distribution for observing k events in a short time interval is investigated experimentally for various measuring times. The experiments to measure the influence of the significant radioactive decay were performed with 89 Y m (T 1/2 =16.06 s), using a multichannel analyser (4096 channels) in the multiscaling mode. According to the results, Poisson statistics describe the counting experiment for short measuring times (up to T=0.5T 1/2 ) and its application is recommended. However, analysis of the data demonstrated, with confidence, that for long measurements (T≥T 1/2 ) Poisson distribution is not valid and the modified Poisson function is preferable. The practical implications in calculating uncertainties and in optimizing the measuring time are discussed. Differences between the standard deviations evaluated on the basis of the Poisson and binomial models are especially significant for experiments with long measuring time (T/T 1/2 ≥2) and/or large detection efficiency (ε>0.30). Optimization of the measuring time for paired observations yields the same solution for either the binomial or the Poisson distribution. (orig.)

  20. Computer modeling describes gravity-related adaptation in cell cultures.

    Science.gov (United States)

    Alexandrov, Ludmil B; Alexandrova, Stoyana; Usheva, Anny

    2009-12-16

    Questions about the changes of biological systems in response to hostile environmental factors are important but not easy to answer. Often, the traditional description with differential equations is difficult due to the overwhelming complexity of the living systems. Another way to describe complex systems is by simulating them with phenomenological models such as the well-known evolutionary agent-based model (EABM). Here we developed an EABM to simulate cell colonies as a multi-agent system that adapts to hyper-gravity in starvation conditions. In the model, the cell's heritable characteristics are generated and transferred randomly to offspring cells. After a qualitative validation of the model at normal gravity, we simulate cellular growth in hyper-gravity conditions. The obtained data are consistent with previously confirmed theoretical and experimental findings for bacterial behavior in environmental changes, including the experimental data from the microgravity Atlantis and the Hypergravity 3000 experiments. Our results demonstrate that it is possible to utilize an EABM with realistic qualitative description to examine the effects of hypergravity and starvation on complex cellular entities.

  1. Why is Facebook so successful? Psychophysiological measures describe a core flow state while using Facebook.

    Science.gov (United States)

    Mauri, Maurizio; Cipresso, Pietro; Balgera, Anna; Villamira, Marco; Riva, Giuseppe

    2011-12-01

    People are more and more using social networking sites (SNSs) like Facebook and MySpace to engage with others. The use of SNSs can have both positive and negative effect on the individual; however, the increasing use of SNSs might reveal that people look for SNSs because they have a positive experience when they use them. Few studies have tried to identify which particular aspects of the social networking experience make SNSs so successful. In this study we focus on the affective experience evoked by SNSs. In particular, we explore whether the use of SNSs elicits a specific psychophysiological pattern. Specifically, we recorded skin conductance, blood volume pulse, electroencephalogram, electromyography, respiratory activity, and pupil dilation in 30 healthy subjects during a 3-minute exposure to (a) a slide show of natural panoramas (relaxation condition), (b) the subject's personal Facebook account, and (c) a Stroop and mathematical task (stress condition). Statistical analysis of the psychophysiological data and pupil dilation indicates that the Facebook experience was significantly different from stress and relaxation on many linear and spectral indices of somatic activity. Moreover, the biological signals revealed that Facebook use can evoke a psychophysiological state characterized by high positive valence and high arousal (Core Flow State). These findings support the hypothesis that the successful spread of SNSs might be associated with a specific positive affective state experienced by users when they use their SNSs account.

  2. Communication skills training: describing a new conceptual model.

    Science.gov (United States)

    Brown, Richard F; Bylund, Carma L

    2008-01-01

    Current research in communication in physician-patient consultations is multidisciplinary and multimethodological. As this research has progressed, a considerable body of evidence on the best practices in physician-patient communication has been amassed. This evidence provides a foundation for communication skills training (CST) at all levels of medical education. Although the CST literature has demonstrated that communication skills can be taught, one critique of this literature is that it is not always clear which skills are being taught and whether those skills are matched with those being assessed. The Memorial Sloan-Kettering Cancer Center Comskil Model for CST seeks to answer those critiques by explicitly defining the important components of a consultation, based on Goals, Plans, and Actions theories and sociolinguistic theory. Sequenced guidelines as a mechanism for teaching about particular communication challenges are adapted from these other methods. The authors propose that consultation communication can be guided by an overarching goal, which is achieved through the use of a set of predetermined strategies. Strategies are common in CST; however, strategies often contain embedded communication skills. These skills can exist across strategies, and the Comskil Model seeks to make them explicit in these contexts. Separate from the skills are process tasks and cognitive appraisals that need to be addressed in teaching. The authors also describe how assessment practices foster concordance between skills taught and those assessed through careful coding of trainees' communication encounters and direct feedback.

  3. INCAS: an analytical model to describe displacement cascades

    Energy Technology Data Exchange (ETDEWEB)

    Jumel, Stephanie E-mail: stephanie.jumel@edf.fr; Claude Van-Duysen, Jean E-mail: jean-claude.van-duysen@edf.fr

    2004-07-01

    REVE (REactor for Virtual Experiments) is an international project aimed at developing tools to simulate neutron irradiation effects in Light Water Reactor materials (Fe, Ni or Zr-based alloys). One of the important steps of the project is to characterise the displacement cascades induced by neutrons. Accordingly, the Department of Material Studies of Electricite de France developed an analytical model based on the binary collision approximation. This model, called INCAS (INtegration of CAScades), was devised to be applied on pure elements; however, it can also be used on diluted alloys (reactor pressure vessel steels, etc.) or alloys composed of atoms with close atomic numbers (stainless steels, etc.). INCAS describes displacement cascades by taking into account the nuclear collisions and electronic interactions undergone by the moving atoms. In particular, it enables to determine the mean number of sub-cascades induced by a PKA (depending on its energy) as well as the mean energy dissipated in each of them. The experimental validation of INCAS requires a large effort and could not be carried out in the framework of the study. However, it was verified that INCAS results are in conformity with those obtained from other approaches. As a first application, INCAS was applied to determine the sub-cascade spectrum induced in iron by the neutron spectrum corresponding to the central channel of the High Flux Irradiation Reactor of Oak Ridge National Laboratory.

  4. INCAS: an analytical model to describe displacement cascades

    Science.gov (United States)

    Jumel, Stéphanie; Claude Van-Duysen, Jean

    2004-07-01

    REVE (REactor for Virtual Experiments) is an international project aimed at developing tools to simulate neutron irradiation effects in Light Water Reactor materials (Fe, Ni or Zr-based alloys). One of the important steps of the project is to characterise the displacement cascades induced by neutrons. Accordingly, the Department of Material Studies of Electricité de France developed an analytical model based on the binary collision approximation. This model, called INCAS (INtegration of CAScades), was devised to be applied on pure elements; however, it can also be used on diluted alloys (reactor pressure vessel steels, etc.) or alloys composed of atoms with close atomic numbers (stainless steels, etc.). INCAS describes displacement cascades by taking into account the nuclear collisions and electronic interactions undergone by the moving atoms. In particular, it enables to determine the mean number of sub-cascades induced by a PKA (depending on its energy) as well as the mean energy dissipated in each of them. The experimental validation of INCAS requires a large effort and could not be carried out in the framework of the study. However, it was verified that INCAS results are in conformity with those obtained from other approaches. As a first application, INCAS was applied to determine the sub-cascade spectrum induced in iron by the neutron spectrum corresponding to the central channel of the High Flux Irradiation Reactor of Oak Ridge National Laboratory.

  5. INCAS: an analytical model to describe displacement cascades

    International Nuclear Information System (INIS)

    Jumel, Stephanie; Claude Van-Duysen, Jean

    2004-01-01

    REVE (REactor for Virtual Experiments) is an international project aimed at developing tools to simulate neutron irradiation effects in Light Water Reactor materials (Fe, Ni or Zr-based alloys). One of the important steps of the project is to characterise the displacement cascades induced by neutrons. Accordingly, the Department of Material Studies of Electricite de France developed an analytical model based on the binary collision approximation. This model, called INCAS (INtegration of CAScades), was devised to be applied on pure elements; however, it can also be used on diluted alloys (reactor pressure vessel steels, etc.) or alloys composed of atoms with close atomic numbers (stainless steels, etc.). INCAS describes displacement cascades by taking into account the nuclear collisions and electronic interactions undergone by the moving atoms. In particular, it enables to determine the mean number of sub-cascades induced by a PKA (depending on its energy) as well as the mean energy dissipated in each of them. The experimental validation of INCAS requires a large effort and could not be carried out in the framework of the study. However, it was verified that INCAS results are in conformity with those obtained from other approaches. As a first application, INCAS was applied to determine the sub-cascade spectrum induced in iron by the neutron spectrum corresponding to the central channel of the High Flux Irradiation Reactor of Oak Ridge National Laboratory

  6. How Did You Survive in the First Five Years? Secrets to Success Described by Apparel New Ventures in China

    OpenAIRE

    Li Zhao; Jung Ha-Brookshire

    2014-01-01

    The study explored the secrets of success described by Chinese apparel new ventures. Barney's (1991) resource-based view of the firm helped the researchers understand secrets to success from the firm's internal perspective, and the social network theory informed key secrets from the external perspective (Ahuja, 2000). In-depth interviews with open-ended questions were employed with sixteen top apparel companies in China. Results revealed that having the first successful store is the symbol of...

  7. Using multistage models to describe radiation-induced leukaemia

    International Nuclear Information System (INIS)

    Little, M.P.; Muirhead, C.R.; Boice, J.D. Jr.; Kleinerman, R.A.

    1995-01-01

    The Armitage-Doll model of carcinogenesis is fitted to data on leukaemia mortality among the Japanese atomic bomb survivors with the DS86 dosimetry and on leukaemia incidence in the International Radiation Study of Cervical Cancer patients. Two different forms of model are fitted: the first postulates up to two radiation-affected stages and the second additionally allows for the presence at birth of a non-trivial population of cells which have already accumulated the first of the mutations leading to malignancy. Among models of the first form, a model with two adjacent radiation-affected stages appears to fit the data better than other models of the first form, including both models with two affected stages in any order and models with only one affected stage. The best fitting model predicts a linear-quadratic dose-response and reductions of relative risk with increasing time after exposure and age at exposure, in agreement with what has previously been observed in the Japanese and cervical cancer data. However, on the whole it does not provide an adequate fit to either dataset. The second form of model appears to provide a rather better fit, but the optimal models have biologically implausible parameters (the number of initiated cells at birth is negative) so that this model must also be regarded as providing an unsatisfactory description of the data. (author)

  8. A new settling velocity model to describe secondary sedimentation.

    Science.gov (United States)

    Ramin, Elham; Wágner, Dorottya S; Yde, Lars; Binning, Philip J; Rasmussen, Michael R; Mikkelsen, Peter Steen; Plósz, Benedek Gy

    2014-12-01

    Secondary settling tanks (SSTs) are the most hydraulically sensitive unit operations in biological wastewater treatment plants. The maximum permissible inflow to the plant depends on the efficiency of SSTs in separating and thickening the activated sludge. The flow conditions and solids distribution in SSTs can be predicted using computational fluid dynamics (CFD) tools. Despite extensive studies on the compression settling behaviour of activated sludge and the development of advanced settling velocity models for use in SST simulations, these models are not often used, due to the challenges associated with their calibration. In this study, we developed a new settling velocity model, including hindered, transient and compression settling, and showed that it can be calibrated to data from a simple, novel settling column experimental set-up using the Bayesian optimization method DREAM(ZS). In addition, correlations between the Herschel-Bulkley rheological model parameters and sludge concentration were identified with data from batch rheological experiments. A 2-D axisymmetric CFD model of a circular SST containing the new settling velocity and rheological model was validated with full-scale measurements. Finally, it was shown that the representation of compression settling in the CFD model can significantly influence the prediction of sludge distribution in the SSTs under dry- and wet-weather flow conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. A new settling velocity model to describe secondary sedimentation

    DEFF Research Database (Denmark)

    Ramin, Elham; Wágner, Dorottya Sarolta; Yde, Lars

    2014-01-01

    Secondary settling tanks (SSTs) are the most hydraulically sensitive unit operations in biological wastewater treatment plants. The maximum permissible inflow to the plant depends on the efficiency of SSTs in separating and thickening the activated sludge. The flow conditions and solids...... distribution in SSTs can be predicted using computational fluid dynamics (CFD) tools. Despite extensive studies on the compression settling behaviour of activated sludge and the development of advanced settling velocity models for use in SST simulations, these models are not often used, due to the challenges...... associated with their calibration. In this study, we developed a new settling velocity model, including hindered, transient and compression settling, and showed that it can be calibrated to data from a simple, novel settling column experimental set-up using the Bayesian optimization method DREAM...

  10. LCM 3.0: A Language for describing Conceptual Models

    NARCIS (Netherlands)

    Feenstra, Remco; Wieringa, Roelf J.

    1993-01-01

    The syntax of the conceptual model specification language LCM is defined. LCM uses equational logic to specify data types and order-sorted dynamic logic to specify objects with identity and mutable state. LCM specifies database transactions as finite sets of atomic object transitions.

  11. A dynamic data based model describing nephropathia epidemica in Belgium

    NARCIS (Netherlands)

    Amirpour Haredasht, S.; Barrios, J.M.; Maes, P.; Verstraeten, W.W.; Clement, J.; Ducoffre, G.; Lagrou, K.; Van Ranst, M.; Coppin, P.; Berckmans, D.; Aerts, J.M.F.G.

    2011-01-01

    ropathia epidemica (NE) is a human infection caused by Puumala virus (PUUV), which is naturally carried and shed by bank voles (Myodes glareolus). Population dynamics and infectious diseases in general, such as NE, have often been modelled with mechanistic SIR (Susceptible, Infective and Remove with

  12. A general modeling framework for describing spatially structured population dynamics

    Science.gov (United States)

    Sample, Christine; Fryxell, John; Bieri, Joanna; Federico, Paula; Earl, Julia; Wiederholt, Ruscena; Mattsson, Brady; Flockhart, Tyler; Nicol, Sam; Diffendorfer, James E.; Thogmartin, Wayne E.; Erickson, Richard A.; Norris, D. Ryan

    2017-01-01

    Variation in movement across time and space fundamentally shapes the abundance and distribution of populations. Although a variety of approaches model structured population dynamics, they are limited to specific types of spatially structured populations and lack a unifying framework. Here, we propose a unified network-based framework sufficiently novel in its flexibility to capture a wide variety of spatiotemporal processes including metapopulations and a range of migratory patterns. It can accommodate different kinds of age structures, forms of population growth, dispersal, nomadism and migration, and alternative life-history strategies. Our objective was to link three general elements common to all spatially structured populations (space, time and movement) under a single mathematical framework. To do this, we adopt a network modeling approach. The spatial structure of a population is represented by a weighted and directed network. Each node and each edge has a set of attributes which vary through time. The dynamics of our network-based population is modeled with discrete time steps. Using both theoretical and real-world examples, we show how common elements recur across species with disparate movement strategies and how they can be combined under a unified mathematical framework. We illustrate how metapopulations, various migratory patterns, and nomadism can be represented with this modeling approach. We also apply our network-based framework to four organisms spanning a wide range of life histories, movement patterns, and carrying capacities. General computer code to implement our framework is provided, which can be applied to almost any spatially structured population. This framework contributes to our theoretical understanding of population dynamics and has practical management applications, including understanding the impact of perturbations on population size, distribution, and movement patterns. By working within a common framework, there is less chance

  13. Describing a Strongly Correlated Model System with Density Functional Theory.

    Science.gov (United States)

    Kong, Jing; Proynov, Emil; Yu, Jianguo; Pachter, Ruth

    2017-07-06

    The linear chain of hydrogen atoms, a basic prototype for the transition from a metal to Mott insulator, is studied with a recent density functional theory model functional for nondynamic and strong correlation. The computed cohesive energy curve for the transition agrees well with accurate literature results. The variation of the electronic structure in this transition is characterized with a density functional descriptor that yields the atomic population of effectively localized electrons. These new methods are also applied to the study of the Peierls dimerization of the stretched even-spaced Mott insulator to a chain of H 2 molecules, a different insulator. The transitions among the two insulating states and the metallic state of the hydrogen chain system are depicted in a semiquantitative phase diagram. Overall, we demonstrate the capability of studying strongly correlated materials with a mean-field model at the fundamental level, in contrast to the general pessimistic view on such a feasibility.

  14. A Biophysical Neural Model To Describe Spatial Visual Attention

    International Nuclear Information System (INIS)

    Hugues, Etienne; Jose, Jorge V.

    2008-01-01

    Visual scenes have enormous spatial and temporal information that are transduced into neural spike trains. Psychophysical experiments indicate that only a small portion of a spatial image is consciously accessible. Electrophysiological experiments in behaving monkeys have revealed a number of modulations of the neural activity in special visual area known as V4, when the animal is paying attention directly towards a particular stimulus location. The nature of the attentional input to V4, however, remains unknown as well as to the mechanisms responsible for these modulations. We use a biophysical neural network model of V4 to address these issues. We first constrain our model to reproduce the experimental results obtained for different external stimulus configurations and without paying attention. To reproduce the known neuronal response variability, we found that the neurons should receive about equal, or balanced, levels of excitatory and inhibitory inputs and whose levels are high as they are in in vivo conditions. Next we consider attentional inputs that can induce and reproduce the observed spiking modulations. We also elucidate the role played by the neural network to generate these modulations

  15. The UIS Model for Online Success

    Science.gov (United States)

    Bloemer, Bill

    2009-01-01

    This case study describes the philosophy underlying the delivery of online programs and courses at the University of Illinois-Springfield. The strategies used to implement the UIS model and the measures used to validate its success are outlined. These factors are reviewed in the context of the Sloan-C Five Pillars for quality learning environments.

  16. MODEL OF TRAINING OF SUCCESS IN LIFE

    Directory of Open Access Journals (Sweden)

    Екатерина Александровна Лежнева

    2014-04-01

    Full Text Available The article explains the importance of the development of motive to succeed in adolescence. It is determined the value of the motive to achieve success in the further development of the teenager: a motive to achieve effective internal forces mobilized for the implementation of successful operation ensures the active involvement of teenagers in social and interpersonal relationships. As the primary means of motive development success is considered training. The author provides a definition of "training for success in life," creates a model of training for success in life, and describes its units (targeted, informative, technological, productive, reveals the successful development of the technology life strategy used during the training (self-presentation, targets, incentives, subject-orientation. The author pays attention to the need for a future psychologist to develop teenagers’ motive to achieve success through the mastery of competence in constructing a model of training for success in life, and its implementation in the course of professional activities. The main means of training students of psychology to the use of training success in life identified the additional educational programs and psychological section.DOI: http://dx.doi.org/10.12731/2218-7405-2013-9-77

  17. Describing Case Study Method and Identifying the Factors that Contribute to the Successful Conduct of Case Studies

    OpenAIRE

    Ahmad H. Juma'h; Mustafa Cavus

    2001-01-01

    This article has attempted to describe case study, the limitations and critiques on case study methodology and how the proponents have responded to these. Our special focus have been on the debate on theory building from case study research, and a framework for conducting case study research as well as the factors for a successful case study research. The overall conclusion is that the case study has been inappropriately used to generate theories.

  18. Ling classification describes endoscopic progressive process of achalasia and successful peroral endoscopy myotomy prevents endoscopic progression of achalasia.

    Science.gov (United States)

    Zhang, Wen-Gang; Linghu, En-Qiang; Chai, Ning-Li; Li, Hui-Kai

    2017-05-14

    To verify the hypothesis that the Ling classification describes the endoscopic progressive process of achalasia and determine the ability of successful peroral endoscopic myotomy (POEM) to prevent endoscopic progression of achalasia. We retrospectively reviewed the endoscopic findings, symptom duration, and manometric data in patients with achalasia. A total of 359 patients (197 women, 162 men) with a mean age of 42.1 years (range, 12-75 years) were evaluated. Symptom duration ranged from 2 to 360 mo, with a median of 36 mo. Patients were classified with Ling type I ( n = 119), IIa ( n = 106), IIb ( n = 60), IIc ( n = 60), or III ( n = 14), according to the Ling classification. Of the 359 patients, 349 underwent POEM, among whom 21 had an endoscopic follow-up for more than 2 years. Pre-treatment and post-treatment Ling classifications of these 21 patients were compared. Symptom duration increased significantly with increasing Ling classification (from I to III) ( P achalasia and may be able to serve as an endoscopic assessment criterion for achalasia. Successful POEM (Eckardt score ≤ 3) seems to have the ability to prevent endoscopic evolvement of achalasia. However, studies with larger populations are warranted to confirm our findings.

  19. Development of a model describing virus removal process in an activated sludge basin

    Energy Technology Data Exchange (ETDEWEB)

    Kim, T.; Shiragami, N. Unno, H. [Tokyo Institute of Technology, Tokyo (Japan)

    1995-06-20

    The virus removal process from the liquid phase in an activated sludge basin possibly consists of physicochemical processes, such as adsorption onto sludge flocs, biological processes such as microbial predating and inactivation by virucidal components excreted by microbes. To describe properly the virus behavior in an activated sludge basin, a simple model is proposed based on the experimental data obtained using a poliovirus type 1. A three-compartments model, which include the virus in the liquid phase and in the peripheral and inner regions of sludge flocs is employed. By using the model, the Virus removal process was successfully simulated to highlight the implication of its distribution in the activated sludge basin. 17 refs., 8 figs.

  20. An extended car-following model to describe connected traffic dynamics under cyberattacks

    Science.gov (United States)

    Wang, Pengcheng; Yu, Guizhen; Wu, Xinkai; Qin, Hongmao; Wang, Yunpeng

    2018-04-01

    In this paper, the impacts of the potential cyberattacks on vehicles are modeled through an extended car-following model. To better understand the mechanism of traffic disturbance under cyberattacks, the linear and nonlinear stability analysis are conducted respectively. Particularly, linear stability analysis is performed to obtain different neutral stability conditions with various parameters; and nonlinear stability analysis is carried out by using reductive perturbation method to derive the soliton solution of the modified Korteweg de Vries equation (mKdV) near the critical point, which is used to draw coexisting stability lines. Furthermore, by applying linear and nonlinear stability analysis, traffic flow state can be divided into three states, i.e., stable, metastable and unstable states which are useful to describe shockwave dynamics and driving behaviors under cyberattacks. The theoretical results show that the proposed car-following model is capable of successfully describing the car-following behavior of connected vehicles with cyberattacks. Finally, numerical simulation using real values has confirmed the validity of theoretical analysis. The results further demonstrate our model can be used to help avoid collisions and relieve traffic congestion with cybersecurity threats.

  1. Developing a Successful Open Source Training Model

    Directory of Open Access Journals (Sweden)

    Belinda Lopez

    2010-01-01

    Full Text Available Training programs for open source software provide a tangible, and sellable, product. A successful training program not only builds revenue, it also adds to the overall body of knowledge available for the open source project. By gathering best practices and taking advantage of the collective expertise within a community, it may be possible for a business to partner with an open source project to build a curriculum that promotes the project and supports the needs of the company's training customers. This article describes the initial approach used by Canonical, the commercial sponsor of the Ubuntu Linux operating system, to engage the community in the creation of its training offerings. We then discuss alternate curriculum creation models and some of the conditions that are necessary for successful collaboration between creators of existing documentation and commercial training providers.

  2. Yeast for Mathematicians: A Ferment of Discovery and Model Competition to Describe Data.

    Science.gov (United States)

    Lewis, Matthew; Powell, James

    2017-02-01

    In addition to the memorization, algorithmic skills and vocabulary which are the default focus in many mathematics classrooms, professional mathematicians are expected to creatively apply known techniques, construct new mathematical approaches and communicate with and about mathematics. We propose that students can learn these professional, higher-level skills through Laboratory Experiences in Mathematical Biology which put students in the role of mathematics researcher creating mathematics to describe and understand biological data. Here we introduce a laboratory experience centered on yeast (Saccharomyces cerevisiae) growing in a small capped flask with a jar to collect carbon dioxide created during yeast growth and respiration. The lab requires no specialized equipment and can easily be run in the context of a college math class. Students collect data and develop mathematical models to explain the data. To help place instructors in the role of mentor/collaborator (as opposed to jury/judge), we facilitate the lab using model competition judged via Bayesian Information Criterion. This article includes details about the class activity conducted, student examples and pedagogical strategies for success.

  3. Review of reactive kinetic models describing reductive dechlorination of chlorinated ethenes in soil and groundwater

    DEFF Research Database (Denmark)

    Chambon, Julie Claire Claudia; Bjerg, Poul Løgstrup; Scheutz, Charlotte

    2013-01-01

    Reductive dechlorination is a major degradation pathway of chlorinated ethenes in anaerobic subsurface environments, and reactive kinetic models describing the degradation process are needed in fate and transport models of these contaminants. However, reductive dechlorination is a complex biologi...

  4. Steady shear rate rheology of suspensions, as described by the gaint floc model

    NARCIS (Netherlands)

    Stein, H.N.; Laven, J.

    2001-01-01

    The break-down of a particle network by shear is described as the development of shear planes: a region able to withstand low shear stresses may break down under a larger stress; thus with increasing shear stress and shear rate, the mutual distance (A) between successive shear planes decreases

  5. A model describing water and salt migration in concrete during wetting/drying cycles

    NARCIS (Netherlands)

    Arends, T.; Taher, A.; van der Zanden, A.J.J.; Brouwers, H.J.H.; Bilek, V.; Kersner, Z.

    2014-01-01

    In order to predict the life span of concrete structures, models describing the migration of chloride are needed. In this paper, a start is made with a simple, theoretical model describing water and chloride transport in a concrete sample. First, transport of water in concrete is considered with

  6. Introducing mixotrophy into a biogeochemical model describing an eutrophied coastal ecosystem: The Southern North Sea

    Science.gov (United States)

    Ghyoot, Caroline; Lancelot, Christiane; Flynn, Kevin J.; Mitra, Aditee; Gypens, Nathalie

    2017-09-01

    Most biogeochemical/ecological models divide planktonic protists between phototrophs (phytoplankton) and heterotrophs (zooplankton). However, a large number of planktonic protists are able to combine several mechanisms of carbon and nutrient acquisition. Not representing these multiple mechanisms in biogeochemical/ecological models describing eutrophied coastal ecosystems can potentially lead to different conclusions regarding ecosystem functioning, especially regarding the success of harmful algae, which are often reported as mixotrophic. This modelling study investigates the implications for trophic dynamics of including 3 contrasting forms of mixotrophy, namely osmotrophy (using alkaline phosphatase activity, APA), non-constitutive mixotrophy (acquired phototrophy by microzooplankton) and also constitutive mixotrophy. The application is in the Southern North Sea, an ecosystem that faced, between 1985 and 2005, a significant increase in the nutrient supply N:P ratio (from 31 to 81 mol N:P). The comparison with a traditional model shows that, when the winter N:P ratio in the Southern North Sea is above 22 molN molP-1 (as occurred from mid-1990s), APA allows a 3-32% increase of annual gross primary production (GPP). In result of the higher GPP, the annual sedimentation increases as well as the bacterial production. By contrast, APA does not affect the export of matter to higher trophic levels because the increased GPP is mainly due to Phaeocystis colonies, which are not grazed by copepods. Under high irradiance, non-constitutive mixotrophy appreciably increases annual GPP, transfer to higher trophic levels, sedimentation, and nutrient remineralisation. In this ecosystem, non-constitutive mixotrophy is also observed to have an indirect stimulating effect on diatoms. Constitutive mixotrophy in nanoflagellates appears to have little influence on this ecosystem functioning. An important conclusion from this work is that contrasting forms of mixotrophy have different

  7. Model of key success factors for Business Intelligence implementation

    Directory of Open Access Journals (Sweden)

    Peter Mesaros

    2016-07-01

    Full Text Available New progressive technologies recorded growth in every area. Information-communication technologies facilitate the exchange of information and it facilitates management of everyday activities in enterprises. Specific modules (such as Business Intelligence facilitate decision-making. Several studies have demonstrated the positive impact of Business Intelligence to decision-making. The first step is to put in place the enterprise. The implementation process is influenced by many factors. This article discusses the issue of key success factors affecting to successful implementation of Business Intelligence. The article describes the key success factors for successful implementation and use of Business Intelligence based on multiple studies. The main objective of this study is to verify the effects and dependence of selected factors and proposes a model of key success factors for successful implementation of Business Intelligence. Key success factors and the proposed model are studied in Slovak enterprises.

  8. Endorsement of Models Describing Sexual Response of Men and Women with a Sexual Partner

    DEFF Research Database (Denmark)

    Giraldi, Annamaria; Kristensen, Ellids; Sand, Michael

    2015-01-01

    , erectile dysfunction and dissatisfaction with sexual life were significantly related to endorsement of the Basson model or none of the models (P = 0.01). CONCLUSIONS: No single model of sexual response could describe men's and women's sexual responses. The majority of men and women with no sexual......INTRODUCTION: Several models have been used to describe men's and women's sexual responses. These models have been conceptualized as linear or circular models. The circular models were proposed to describe women's sexual function best. AIM: This study aims to determine whether men and women thought...... that current theoretical models of sexual responses accurately reflected their own sexual experience and to what extent this was influenced by sexual dysfunction. METHODS: A cross-sectional study of a large, broadly sampled, nonclinical population, cohort of Danish men and women. The Female Sexual Function...

  9. [Active ageing and success: A brief history of conceptual models].

    Science.gov (United States)

    Petretto, Donatella Rita; Pili, Roberto; Gaviano, Luca; Matos López, Cristina; Zuddas, Carlo

    2016-01-01

    The aim of this paper is to analyse and describe different conceptual models of successful ageing, active and healthy ageing developed in Europe and in America in the 20° century, starting from Rowe and Kahn's original model (1987, 1997). A narrative review was conducted on the literature on successful ageing. Our review included definition of successful ageing from European and American scholars. Models were found that aimed to describe indexes of active and healthy ageing, models devoted to describe processes involved in successful ageing, and additional views that emphasise subjective and objective perception of successful ageing. A description is also given of critiques on previous models and remedies according to Martin et al. (2014) and strategies for successful ageing according to Jeste and Depp (2014). The need is discussed for the enhancement of Rowe and Kahn's model and other models with a more inclusive, universal description of ageing, incorporating scientific evidence regarding active ageing. Copyright © 2015 SEGG. Publicado por Elsevier España, S.L.U. All rights reserved.

  10. FUZZY MODELING BY SUCCESSIVE ESTIMATION OF RULES ...

    African Journals Online (AJOL)

    This paper presents an algorithm for automatically deriving fuzzy rules directly from a set of input-output data of a process for the purpose of modeling. The rules are extracted by a method termed successive estimation. This method is used to generate a model without truncating the number of fired rules, to within user ...

  11. A revised multi-Fickian moisture transport model to describe non-Fickian effects in wood

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Damkilde, Lars; Svensson, Staffan

    2007-01-01

    This paper presents a study and a refinement of the sorption rate model in a so-called multi-Fickian or multi-phase model. This type of model describes the complex moisture transport system in wood, which consists of separate water vapor and bound-water diffusion interacting through sorption...... sorption allow a simplification of the system to be modeled by a single Fickian diffusion equation. To determine the response of the system, the sorption rate model is essential. Here the function modeling the moisture-dependent adsorption rate is investigated based on existing experiments on thin wood...

  12. A Model of Successful School Leadership from the International Successful School Principalship Project

    Directory of Open Access Journals (Sweden)

    David Gurr

    2015-03-01

    Full Text Available The International Successful School Principalship Project (ISSPP has been actively conducting research about the work of successful principals since 2001. Findings from four project books and eight models derived from this project are synthesised into a model of successful school leadership. Building on Gurr, Drysdale and Mulford’s earlier model, the work of school leaders is described as engaging within the school context to influence student and school outcomes through interventions in teaching and learning, school capacity building, and the wider context. The qualities a leader brings to their role, a portfolio approach to using leadership ideas, constructing networks, collaborations and partnerships, and utilising accountability and evaluation for evidence-informed improvement, are important additional elements. The model is applicable to all in leadership roles in schools.

  13. A model based on soil structural aspects describing the fate of genetically modified bacteria in soil

    NARCIS (Netherlands)

    Hoeven, van der N.; Elsas, van J.D.; Heijnen, C.E.

    1996-01-01

    A computer simulation model was developed which describes growth and competition of bacteria in the soil environment. In the model, soil was assumed to contain millions of pores of a few different size classes. An introduced bacterial strain, e.g. a genetically modified micro-organism (GEMMO), was

  14. CLIC Detector Concepts as described in the CDR: Differences between the GEANT4 and Engineering Models

    CERN Document Server

    Elsener, K; Schlatter, D; Siegrist, N

    2011-01-01

    The CLIC_ILD and CLIC_SiD detector concepts as used for the CDR Vol. 2 in 2011 exist both in GEANT4 simulation models and in engineering layout drawings. At this early stage of a conceptual design, there are inevitably differences between these models, which are described in this note.

  15. Numerical model describing the heat transfer between combustion products and ventilation-system duct walls

    International Nuclear Information System (INIS)

    Bolstad, J.W.; Foster, R.D.; Gregory, W.S.

    1983-01-01

    A package of physical models simulating the heat transfer processes occurring between combustion gases and ducts in ventilation systems is described. The purpose of the numerical model is to predict how the combustion gas in a system heats up or cools down as it flows through the ducts in a ventilation system under fire conditions. The model treats a duct with (forced convection) combustion gases flowing on the inside and stagnant ambient air on the outside. The model is composed of five submodels of heat transfer processes along with a numerical solution procedure to evaluate them. Each of these quantities is evaluated independently using standard correlations based on experimental data. The details of the physical assumptions, simplifications, and ranges of applicability of the correlations are described. A typical application of this model to a full-scale fire test is discussed, and model predictions are compared with selected experimental data

  16. A standard protocol for describing individual-based and agent-based models

    Science.gov (United States)

    Grimm, Volker; Berger, Uta; Bastiansen, Finn; Eliassen, Sigrunn; Ginot, Vincent; Giske, Jarl; Goss-Custard, John; Grand, Tamara; Heinz, Simone K.; Huse, Geir; Huth, Andreas; Jepsen, Jane U.; Jorgensen, Christian; Mooij, Wolf M.; Muller, Birgit; Pe'er, Guy; Piou, Cyril; Railsback, Steven F.; Robbins, Andrew M.; Robbins, Martha M.; Rossmanith, Eva; Ruger, Nadja; Strand, Espen; Souissi, Sami; Stillman, Richard A.; Vabo, Rune; Visser, Ute; DeAngelis, Donald L.

    2006-01-01

    Simulation models that describe autonomous individual organisms (individual based models, IBM) or agents (agent-based models, ABM) have become a widely used tool, not only in ecology, but also in many other disciplines dealing with complex systems made up of autonomous entities. However, there is no standard protocol for describing such simulation models, which can make them difficult to understand and to duplicate. This paper presents a proposed standard protocol, ODD, for describing IBMs and ABMs, developed and tested by 28 modellers who cover a wide range of fields within ecology. This protocol consists of three blocks (Overview, Design concepts, and Details), which are subdivided into seven elements: Purpose, State variables and scales, Process overview and scheduling, Design concepts, Initialization, Input, and Submodels. We explain which aspects of a model should be described in each element, and we present an example to illustrate the protocol in use. In addition, 19 examples are available in an Online Appendix. We consider ODD as a first step for establishing a more detailed common format of the description of IBMs and ABMs. Once initiated, the protocol will hopefully evolve as it becomes used by a sufficiently large proportion of modellers.

  17. A statistical model describing combined irreversible electroporation and electroporation-induced blood-brain barrier disruption.

    Science.gov (United States)

    Sharabi, Shirley; Kos, Bor; Last, David; Guez, David; Daniels, Dianne; Harnof, Sagi; Mardor, Yael; Miklavcic, Damijan

    2016-03-01

    Electroporation-based therapies such as electrochemotherapy (ECT) and irreversible electroporation (IRE) are emerging as promising tools for treatment of tumors. When applied to the brain, electroporation can also induce transient blood-brain-barrier (BBB) disruption in volumes extending beyond IRE, thus enabling efficient drug penetration. The main objective of this study was to develop a statistical model predicting cell death and BBB disruption induced by electroporation. This model can be used for individual treatment planning. Cell death and BBB disruption models were developed based on the Peleg-Fermi model in combination with numerical models of the electric field. The model calculates the electric field thresholds for cell kill and BBB disruption and describes the dependence on the number of treatment pulses. The model was validated using in vivo experimental data consisting of rats brains MRIs post electroporation treatments. Linear regression analysis confirmed that the model described the IRE and BBB disruption volumes as a function of treatment pulses number (r(2) = 0.79; p disruption, the ratio increased with the number of pulses. BBB disruption radii were on average 67% ± 11% larger than IRE volumes. The statistical model can be used to describe the dependence of treatment-effects on the number of pulses independent of the experimental setup.

  18. Successful and unsuccessful psychopaths: a neurobiological model.

    Science.gov (United States)

    Gao, Yu; Raine, Adrian

    2010-01-01

    Despite increasing interest in psychopathy research, surprisingly little is known about the etiology of non-incarcerated, successful psychopaths. This review provides an analysis of current knowledge on the similarities and differences between successful and unsuccessful psychopaths derived from five population sources: community samples, individuals from employment agencies, college students, industrial psychopaths, and serial killers. An initial neurobiological model of successful and unsuccessful psychopathy is outlined. It is hypothesized that successful psychopaths have intact or enhanced neurobiological functioning that underlies their normal or even superior cognitive functioning, which in turn helps them to achieve their goals using more covert and nonviolent methods. In contrast, in unsuccessful, caught psychopaths, brain structural and functional impairments together with autonomic nervous system dysfunction are hypothesized to underlie cognitive and emotional deficits and more overt violent offending.

  19. An algorithm to detect and communicate the differences in computational models describing biological systems.

    Science.gov (United States)

    Scharm, Martin; Wolkenhauer, Olaf; Waltemath, Dagmar

    2016-02-15

    Repositories support the reuse of models and ensure transparency about results in publications linked to those models. With thousands of models available in repositories, such as the BioModels database or the Physiome Model Repository, a framework to track the differences between models and their versions is essential to compare and combine models. Difference detection not only allows users to study the history of models but also helps in the detection of errors and inconsistencies. Existing repositories lack algorithms to track a model's development over time. Focusing on SBML and CellML, we present an algorithm to accurately detect and describe differences between coexisting versions of a model with respect to (i) the models' encoding, (ii) the structure of biological networks and (iii) mathematical expressions. This algorithm is implemented in a comprehensive and open source library called BiVeS. BiVeS helps to identify and characterize changes in computational models and thereby contributes to the documentation of a model's history. Our work facilitates the reuse and extension of existing models and supports collaborative modelling. Finally, it contributes to better reproducibility of modelling results and to the challenge of model provenance. The workflow described in this article is implemented in BiVeS. BiVeS is freely available as source code and binary from sems.uni-rostock.de. The web interface BudHat demonstrates the capabilities of BiVeS at budhat.sems.uni-rostock.de. © The Author 2015. Published by Oxford University Press.

  20. A consilience model to describe N2O production during biological N removal

    DEFF Research Database (Denmark)

    Domingo Felez, Carlos; Smets, Barth F.

    2016-01-01

    Nitrous oxide (N2O), a potent greenhouse gas, is produced during biological nitrogen conversion in wastewater treatment operations. Complex mechanisms underlie N2O production by autotrophic and heterotrophic organisms, which continue to be unravelled. Mathematical models that describe nitric oxide...... (NO) and N2O dynamics have been proposed. Here, a first comprehensive model that considers all relevant NO and N2O production and consumption mechanisms is proposed. The model describes autotrophic NO production by ammonia oxidizing bacteria associated with ammonia oxidation and with nitrite reduction......, followed by NO reduction to N2O. It also considers NO and N2O as intermediates in heterotrophic denitrification in a 4-step model. Three biological NO and N2O production pathways are accounted for, improving the capabilities of existing models while not increasing their complexity. Abiotic contributions...

  1. Describing the processes of propagation and eliminating wildfires with the use of agent models

    Directory of Open Access Journals (Sweden)

    G. A. Dorrer

    2017-10-01

    Full Text Available A new method of describing the processes of propagation and elimination of wildfires on the basis of agent-based modeling is proposed. The main structural units of the creation of such models are the classes of active objects (agents. Agent approach, combined with Geographic Information Systems (GIS can effectively describe the interaction of a large number of participants in the process to combat wildfires: fire spreading, fire crews, mechanization, aerial means and other. In this paper we propose a multi-agent model to predict the spread of wildfire edge and simulate the direct method of extinguishing a ground fire with non-mechanized crews. The model consist with two classes of agents, designated A and B. The burning fire edge is represented as a chain of A-agents, each of which simulates the burning of an elementary portion of vegetation fuel. Fire front movement (moving the A-agent described by the Hamilton-Jacobi equation with using the indicatrises of normal front rate of spread (figurotris. The configuration of the front calculated on basis the algorithm of mobile grids. Agents other type, B-agents, described extinguishing process; they move to the agents of A type and act on them, reducing the combustion intensity to zero. Modeling system presented as two-level coloured nested Petri Net, which describes the agents’ interaction semantics. This model is implemented as a GIS-oriented software system that can be useful both in the fire fighting management as well as in staff training tactics to fighting wildfires. Some examples of modeling decision making on а ground fire extinguishing are presented.

  2. Mathematical Modeling Projects: Success for All Students

    Science.gov (United States)

    Shelton, Therese

    2018-01-01

    Mathematical modeling allows flexibility for a project-based experience. We share details of our regular capstone course, successful for virtually 100% of our math majors for almost two decades. Our research-like approach in this course accommodates a variety of student backgrounds and interests, and has produced some award-winning student…

  3. A model to describe potential effects of chemotherapy on critical radiobiological treatments

    International Nuclear Information System (INIS)

    Rodríguez-Pérez, D.; Desco, M.M.; Antoranz, J.C.

    2016-01-01

    Although chemo- and radiotherapy can annihilate tumors on their own. they are also used in coadjuvancy: improving local effects of radiotherapy using chemotherapy as a radiosensit.izer. The effects of radiotherapy are well described by current radiobiological models. The goal of this work is to describe a discrete radiotherapy model, that has been previously used describe high radiation dose response as well as unusual radio-responses of some types of tumors (e.g. prostate cancer), to obtain a model of chemo+radiotherapy that can describe how the outcome of their combination is a more efficient removal of the tumor. Our hypothesis is that, although both treatments haven different mechanisms, both affect similar key points of cell metabolism and regulation, that lead to cellular death. Hence, we will consider a discrete model where chemotherapy may affect a fraction of the same targets destroyed by radiotherapy. Although radiotherapy reaches all cells equally, chemotherapy diffuses through a tumor attaining lower concentration in its center and higher in its surface. With our simulations we study the enhanced effect of combined therapy treatment and how it depends on the tissue critical parameters (the parameters of the lion-extensive radiobiological model), the number of “targets” aimed at by chemotherapy, and the concentration and diffusion rate of the drug inside the tumor. The results show that an equivalent, cliemo-radio-dose can be computed that allows the prediction of the lower radiation dose that causes the same effect than a radio-only treatment. (paper)

  4. A model to describe potential effects of chemotherapy on critical radiobiological treatments

    Science.gov (United States)

    Rodríguez-Pérez, D.; Desco, M. M.; Antoranz, J. C.

    2016-08-01

    Although chemo- and radiotherapy can annihilate tumors on their own. they are also used in coadjuvancy: improving local effects of radiotherapy using chemotherapy as a radiosensit.izer. The effects of radiotherapy are well described by current radiobiological models. The goal of this work is to describe a discrete radiotherapy model, that has been previously used describe high radiation dose response as well as unusual radio-responses of some types of tumors (e.g. prostate cancer), to obtain a model of chemo+radiotherapy that can describe how the outcome of their combination is a more efficient removal of the tumor. Our hypothesis is that, although both treatments haven different mechanisms, both affect similar key points of cell metabolism and regulation, that lead to cellular death. Hence, we will consider a discrete model where chemotherapy may affect a fraction of the same targets destroyed by radiotherapy. Although radiotherapy reaches all cells equally, chemotherapy diffuses through a tumor attaining lower concentration in its center and higher in its surface. With our simulations we study the enhanced effect of combined therapy treatment and how it depends on the tissue critical parameters (the parameters of the lion-extensive radiobiological model), the number of “targets” aimed at by chemotherapy, and the concentration and diffusion rate of the drug inside the tumor. The results show that an equivalent, cliemo-radio-dose can be computed that allows the prediction of the lower radiation dose that causes the same effect than a radio-only treatment.

  5. A two component model describing nucleon structure functions in the low-x region

    Energy Technology Data Exchange (ETDEWEB)

    Bugaev, E.V. [Institute for Nuclear Research of the Russian Academy of Sciences, 7a, 60th October Anniversary prospect, Moscow 117312 (Russian Federation); Mangazeev, B.V. [Irkutsk State University, 1, Karl Marx Street, Irkutsk 664003 (Russian Federation)

    2009-12-15

    A two component model describing the electromagnetic nucleon structure functions in the low-x region, based on generalized vector dominance and color dipole approaches is briefly described. The model operates with the mesons of rho-family having the mass spectrum of the form m{sub n}{sup 2}=m{sub r}ho{sup 2}(1+2n) and takes into account the nondiagonal transitions in meson-nucleon scattering. The special cut-off factors are introduced in the model, to exclude the gamma-qq-bar-V transitions in the case of narrow qq-bar-pairs. For the color dipole part of the model the well known FKS-parameterization is used.

  6. A STRUCTURAL MODEL DESCRIBE CHINESE TRADESMEN ATTITUDES TOWARDS GREEK STUDENTS CONSUMPTION BEHAVIOR

    Directory of Open Access Journals (Sweden)

    Sofia D. ANASTASIADOU

    2012-12-01

    Full Text Available This study tests evaluates 43 Chinese tradesmen opinios describe the main factors that influnce Greek consumers’ behavior. A structural model was constructed to represent the relationship between consumer components. The model was tested for its Convergent and Discriminant Validity. Moreover it was tested for its reliability and construct reliability. The findings from this study may be used by Chinese tradesmen to develop their marketing campains and customers.

  7. Muscle activation described with a differential equation model for large ensembles of locally coupled molecular motors.

    Science.gov (United States)

    Walcott, Sam

    2014-10-01

    Molecular motors, by turning chemical energy into mechanical work, are responsible for active cellular processes. Often groups of these motors work together to perform their biological role. Motors in an ensemble are coupled and exhibit complex emergent behavior. Although large motor ensembles can be modeled with partial differential equations (PDEs) by assuming that molecules function independently of their neighbors, this assumption is violated when motors are coupled locally. It is therefore unclear how to describe the ensemble behavior of the locally coupled motors responsible for biological processes such as calcium-dependent skeletal muscle activation. Here we develop a theory to describe locally coupled motor ensembles and apply the theory to skeletal muscle activation. The central idea is that a muscle filament can be divided into two phases: an active and an inactive phase. Dynamic changes in the relative size of these phases are described by a set of linear ordinary differential equations (ODEs). As the dynamics of the active phase are described by PDEs, muscle activation is governed by a set of coupled ODEs and PDEs, building on previous PDE models. With comparison to Monte Carlo simulations, we demonstrate that the theory captures the behavior of locally coupled ensembles. The theory also plausibly describes and predicts muscle experiments from molecular to whole muscle scales, suggesting that a micro- to macroscale muscle model is within reach.

  8. Robustness of a cross contamination model describing transfer of pathogens during grinding of meat

    DEFF Research Database (Denmark)

    Møller, Cleide Oliveira de Almeida; Sant’Ana, A. S.; Hansen, Solvej Katrine Holm

    2016-01-01

    This study aimed to evaluate a cross contamination model for its capability of describing transfer of Salmonella spp. and L. monocytogenes during grinding of varying sizes and numbers of pieces of meats in two grinder systems. Data from 19 trials were collected. Three evaluation approaches were...

  9. Robustness of a cross contamination model describing transfer of pathogens during grinding of meat

    DEFF Research Database (Denmark)

    Møller, Cleide Oliveira de Almeida; Sant’Ana, A. S.; Hansen, Solvej Katrine Holm

    2016-01-01

    This study aimed to evaluate a cross contamination model for its capability of describing transfer of Salmonella spp. and L. monocytogenes during grinding of varying sizes and numbers of pieces of meats in two grinder systems. Data from 19 trials were collected. Three evaluation approaches were a...... that grinding was influenced by sharpness of grinder knife, specific grinder and grinding temperature....

  10. Development of a Pharmacokinetic Model to Describe the Complex Pharmacokinetics of Pazopanib in Cancer Patients

    NARCIS (Netherlands)

    Yu, Huixin; van Erp, Nielka; Bins, Sander; Mathijssen, Ron H J; Schellens, Jan H M; Beijnen, Jos H.; Steeghs, Neeltje; Huitema, Alwin D R

    Background and Objective: Pazopanib is a multi-targeted anticancer tyrosine kinase inhibitor. This study was conducted to develop a population pharmacokinetic (popPK) model describing the complex pharmacokinetics of pazopanib in cancer patients. Methods: Pharmacokinetic data were available from 96

  11. Development of a Pharmacokinetic Model to Describe the Complex Pharmacokinetics of Pazopanib in Cancer Patients

    NARCIS (Netherlands)

    Yu, H.; Erp, N. van; Bins, S.; Mathijssen, R.H.; Schellens, J.H.; Beijnen, J.H.; Steeghs, N.; Huitema, A.D.

    2017-01-01

    BACKGROUND AND OBJECTIVE: Pazopanib is a multi-targeted anticancer tyrosine kinase inhibitor. This study was conducted to develop a population pharmacokinetic (popPK) model describing the complex pharmacokinetics of pazopanib in cancer patients. METHODS: Pharmacokinetic data were available from 96

  12. Structural Models Describing Placebo Treatment Effects in Schizophrenia and Other Neuropsychiatric Disorders

    NARCIS (Netherlands)

    Reddy, Venkatesh Pilla; Kozielska, Magdalena; Johnson, Martin; Vermeulen, An; de Greef, Rik; Liu, Jing; Groothuis, Geny M. M.; Danhof, Meindert; Proost, Johannes H.

    2011-01-01

    Large variation in placebo response within and among clinical trials can substantially affect conclusions about the efficacy of new medications in psychiatry. Developing a robust placebo model to describe the placebo response is important to facilitate quantification of drug effects, and eventually

  13. Early Childhood Teacher Preparation: A Tale of Authors and Multimedia, A Model of Technology Integration Described.

    Science.gov (United States)

    Wetzel, Keith; McLean, S. V.

    1997-01-01

    Describes collaboration of two teacher educators, one in early childhood language arts and one in computers in education. Discusses advantages and disadvantages and extensions of this model, including how a college-wide survey revealed that students in teamed courses are better prepared to teach and learn with technology. (DR)

  14. Describing Growth Pattern of Bali Cows Using Non-linear Regression Models

    Directory of Open Access Journals (Sweden)

    Mohd. Hafiz A.W

    2016-12-01

    Full Text Available The objective of this study was to evaluate the best fit non-linear regression model to describe the growth pattern of Bali cows. Estimates of asymptotic mature weight, rate of maturing and constant of integration were derived from Brody, von Bertalanffy, Gompertz and Logistic models which were fitted to cross-sectional data of body weight taken from 74 Bali cows raised in MARDI Research Station Muadzam Shah Pahang. Coefficient of determination (R2 and residual mean squares (MSE were used to determine the best fit model in describing the growth pattern of Bali cows. Von Bertalanffy model was the best model among the four growth functions evaluated to determine the mature weight of Bali cattle as shown by the highest R2 and lowest MSE values (0.973 and 601.9, respectively, followed by Gompertz (0.972 and 621.2, respectively, Logistic (0.971 and 648.4, respectively and Brody (0.932 and 660.5, respectively models. The correlation between rate of maturing and mature weight was found to be negative in the range of -0.170 to -0.929 for all models, indicating that animals of heavier mature weight had lower rate of maturing. The use of non-linear model could summarize the weight-age relationship into several biologically interpreted parameters compared to the entire lifespan weight-age data points that are difficult and time consuming to interpret.

  15. Comparison of six different models describing survival of mammalian cells after irradiation

    International Nuclear Information System (INIS)

    Sontag, W.

    1990-01-01

    Six different cell-survival models have been compared. All models are based on the similar assumption that irradiated cells are able to exist in one of three states. S A is the state of a totally repaired cell, in state S C the cell contains lethal lesions and in state S b the cell contains potentially lethal lesions i.e. those which either can be repaired or converted into lethal lesions. The differences between the six models lie in the different mathematical relationships between the three states. To test the six models, six different sets of experimental data were used which describe cell survival at different repair times after irradiation with sparsely ionizing irradiation. In order to compare the models, a goodness-of-fit function was used. The differences between the six models were tested by use of the nonparametric Mann-Whitney two sample test. Based on the 95% confidence limit, this required separation into three groups. (orig.)

  16. Modeling student success in engineering education

    Science.gov (United States)

    Jin, Qu

    In order for the United States to maintain its global competitiveness, the long-term success of our engineering students in specific courses, programs, and colleges is now, more than ever, an extremely high priority. Numerous studies have focused on factors that impact student success, namely academic performance, retention, and/or graduation. However, there are only a limited number of works that have systematically developed models to investigate important factors and to predict student success in engineering. Therefore, this research presents three separate but highly connected investigations to address this gap. The first investigation involves explaining and predicting engineering students' success in Calculus I courses using statistical models. The participants were more than 4000 first-year engineering students (cohort years 2004 - 2008) who enrolled in Calculus I courses during the first semester in a large Midwestern university. Predictions from statistical models were proposed to be used to place engineering students into calculus courses. The success rates were improved by 12% in Calculus IA using predictions from models developed over traditional placement method. The results showed that these statistical models provided a more accurate calculus placement method than traditional placement methods and help improve success rates in those courses. In the second investigation, multi-outcome and single-outcome neural network models were designed to understand and to predict first-year retention and first-year GPA of engineering students. The participants were more than 3000 first year engineering students (cohort years 2004 - 2005) enrolled in a large Midwestern university. The independent variables include both high school academic performance factors and affective factors measured prior to entry. The prediction performances of the multi-outcome and single-outcome models were comparable. The ability to predict cumulative GPA at the end of an engineering

  17. New Model to describe the interaction of slow neutrons with solid deuterium

    International Nuclear Information System (INIS)

    Granada, J.R

    2009-01-01

    A new scattering kernel to describe the interaction of slow neutrons with solid Deuterium was developed. The main characteristics of that system are contained in the formalism, including the lattice s density of states, the Young-Koppel quantum treatment of the rotations, and the internal molecular vibrations. The elastic processes involving coherent and incoherent contributions are fully described, as well as the spin-correlation effects. The results from the new model are compared with the best available experimental data, showing very good agreement. [es

  18. Regularization of a massless dirac model to describe anomalous electromagnetic response of Weyl semimetals

    International Nuclear Information System (INIS)

    Takane, Yoshitake

    2016-01-01

    An unbounded massless Dirac model with two nondegenerate Dirac cones is the simplest model for Weyl semimetals, which show the anomalous electromagnetic response of chiral magnetic effect (CME) and anomalous Hall effect (AHE). However, if this model is naively used to analyze the electromagnetic response within a linear response theory, it gives the result apparently inconsistent with the persuasive prediction based on a lattice model. We show that this serious difficulty is related to the breaking of current conservation in the Dirac model due to quantum anomaly and can be removed if current and charge operators are redefined to include the contribution from the anomaly. We demonstrate that the CME as well as the AHE can be properly described using newly defined operators, and clarify that the CME is determined by the competition between the contribution from the anomaly and that from low-energy electrons. (author)

  19. A theoretical model to describe progressions and regressions for exercise rehabilitation.

    Science.gov (United States)

    Blanchard, Sam; Glasgow, Phil

    2014-08-01

    This article aims to describe a new theoretical model to simplify and aid visualisation of the clinical reasoning process involved in progressing a single exercise. Exercise prescription is a core skill for physiotherapists but is an area that is lacking in theoretical models to assist clinicians when designing exercise programs to aid rehabilitation from injury. Historical models of periodization and motor learning theories lack any visual aids to assist clinicians. The concept of the proposed model is that new stimuli can be added or exchanged with other stimuli, either intrinsic or extrinsic to the participant, in order to gradually progress an exercise whilst remaining safe and effective. The proposed model maintains the core skills of physiotherapists by assisting clinical reasoning skills, exercise prescription and goal setting. It is not limited to any one pathology or rehabilitation setting and can adapted by any level of skilled clinician. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Using concept maps to describe undergraduate students’ mental model in microbiology course

    Science.gov (United States)

    Hamdiyati, Y.; Sudargo, F.; Redjeki, S.; Fitriani, A.

    2018-05-01

    The purpose of this research was to describe students’ mental model in a mental model based-microbiology course using concept map as assessment tool. Respondents were 5th semester of undergraduate students of Biology Education of Universitas Pendidikan Indonesia. The mental modelling instrument used was concept maps. Data were taken on Bacteria sub subject. A concept map rubric was subsequently developed with a maximum score of 4. Quantitative data was converted into a qualitative one to determine mental model level, namely: emergent = score 1, transitional = score 2, close to extended = score 3, and extended = score 4. The results showed that mental model level on bacteria sub subject before the implementation of mental model based-microbiology course was at the transitional level. After implementation of mental model based-microbiology course, mental model was at transitional level, close to extended, and extended. This indicated an increase in the level of students’ mental model after the implementation of mental model based-microbiology course using concept map as assessment tool.

  1. Describing the clinical reasoning process: application of a model of enablement to a pediatric case.

    Science.gov (United States)

    Furze, Jennifer; Nelson, Kelly; O'Hare, Megan; Ortner, Amanda; Threlkeld, A Joseph; Jensen, Gail M

    2013-04-01

    Clinical reasoning is a core tenet of physical therapy practice leading to optimal patient care. The purpose of this case was to describe the outcomes, subjective experience, and reflective clinical reasoning process for a child with cerebral palsy using the International Classification of Functioning, Disability, and Health (ICF) model. Application of the ICF framework to a 9-year-old boy with spastic triplegic cerebral palsy was utilized to capture the interwoven factors present in this case. Interventions in the pool occurred twice weekly for 1 h over a 10-week period. Immediately post and 4 months post-intervention, the child made functional and meaningful gains. The family unit also developed an enjoyment of exercising together. Each individual family member described psychological, emotional, or physical health improvements. Reflection using the ICF model as a framework to discuss clinical reasoning can highlight important factors contributing to effective patient management.

  2. Development of zircaloy deformation model to describe the zircaloy-4 cladding tube during accidents

    International Nuclear Information System (INIS)

    Raff, S.

    1978-01-01

    The development of a high-temperature deformation model for Zircaloy-4 cans is primarily based on numerous well-parametrized tensile tests to get the material behaviour including statistical variance. It is shown that plastic deformation may be described by a power creep law, the coefficients of which show strong dependence on temperature in the relevant temperature region. These coefficients have been determined. A model based on these coefficients has been established which, apart from best estimate deformation, gives upper and lower bounds of possible deformation. The model derived from isothermal uniaxial tests is being verified against isothermal and transient tube burst tests. The influence of preoxidation and increased oxygen concentration during deformation is modeled on the basis of the pseudobinary Zircaloy-oxygen phase diagram. (author)

  3. Calibration and validation of a model describing complete autotrophic nitrogen removal in a granular SBR system

    DEFF Research Database (Denmark)

    Vangsgaard, Anna Katrine; Mutlu, Ayten Gizem; Gernaey, Krist

    2013-01-01

    BACKGROUND: A validated model describing the nitritation-anammox process in a granular sequencing batch reactor (SBR) system is an important tool for: a) design of future experiments and b) prediction of process performance during optimization, while applying process control, or during system scale......-up. RESULTS: A model was calibrated using a step-wise procedure customized for the specific needs of the system. The important steps in the procedure were initialization, steady-state and dynamic calibration, and validation. A fast and effective initialization approach was developed to approximate pseudo...... screening of the parameter space proposed by Sin et al. (2008) - to find the best fit of the model to dynamic data. Finally, the calibrated model was validated with an independent data set. CONCLUSION: The presented calibration procedure is the first customized procedure for this type of system...

  4. An empirical model describing the postnatal growth of organs in ICRP reference humans: Pt. 1

    International Nuclear Information System (INIS)

    Walker, J.T.

    1991-01-01

    An empirical model is presented for describing the postnatal mass growth of lungs in ICRP reference humans. A combined exponential and logistic function containing six parameters is fitted to ICRP 23 lung data using a weighted non-linear least squares technique. The results indicate that the model delineates the data well. Further analysis shows that reference male lungs attain a higher pubertal peak velocity (PPV) and adult mass size than female lungs, although the latter reach their PPV and adult mass size first. Furthermore, the model shows that lung growth rates in infants are two to three orders of magnitude higher than those in mature adults. This finding is important because of the possible association between higher radiation risks in infants' organs that have faster cell turnover rates compared to mature adult organs. The significance of the model for ICRP dosimetric purposes will be discussed. (author)

  5. A relativistic gauge model describing N particles bound by harmonic forces

    International Nuclear Information System (INIS)

    Filippov, A.T.

    1987-01-01

    Application of the principle of gauging to linear canonical symmetries of simplest/rudimentary/bilinear lagrangians is shown to produce a relativistic version of the Lagrangian describing N particles bound by harmonic forces. For pairwise coupled identical particles the gauge group is T 1 xU 1 , xSU N-1 . A model for the relativistic discrete string (a chain of N particles) is also discussed. All these gauge theoried of particles can be quantized by standard methods

  6. Composite model describing the excitation and de-excitation of nitrogen by an electron beam

    International Nuclear Information System (INIS)

    Kassem, A.E.; Hickman, R.S.

    1975-01-01

    Based on recent studies, the effect of re-excited ions in the emission of electron beam induced fluorescence in nitrogen has been estimated. These effects are included in the formulation of a composite model describing the excitation and de-excitation of nitrogen by an electron beam. The shortcomings of previous models, namely the dependence of the measured temperature on true gas temperature as well as the gas density, are almost completely eliminated in the range of temperatures and densities covered by the available data. (auth)

  7. Validation of mathematical models to describe fluid dynamics of a cold riser by gamma ray attenuation

    International Nuclear Information System (INIS)

    Melo, Ana Cristina Bezerra Azedo de

    2004-12-01

    The fluid dynamic behavior of a riser in a cold type FCC model was investigated by means of catalyst concentration distribution measured with gamma attenuation and simulated with a mathematical model. In the riser of the cold model, MEF, 0,032 m in diameter, 2,30 m in length the fluidized bed, whose components are air and FCC catalyst, circulates. The MEF is operated by automatic control and instruments for measuring fluid dynamic variables. An axial catalyst concentration distribution was measured using an Am-241 gamma source and a NaI detector coupled to a multichannel provided with a software for data acquisition and evaluation. The MEF was adapted for a fluid dynamic model validation which describes the flow in the riser, for example, by introducing an injector for controlling the solid flow in circulation. Mathematical models were selected from literature, analyzed and tested to simulate the fluid dynamic of the riser. A methodology for validating fluid dynamic models was studied and implemented. The stages of the work were developed according to the validation methodology, such as data planning experiments, study of the equations which describe the fluidodynamic, computational solvers application and comparison with experimental data. Operational sequences were carried out keeping the MEF conditions for measuring catalyst concentration and simultaneously measuring the fluid dynamic variables, velocity of the components and pressure drop in the riser. Following this, simulated and experimental values were compared and statistical data treatment done, aiming at the required precision to validate the fluid dynamic model. The comparison tests between experimental and simulated data were carried out under validation criteria. The fluid dynamic behavior of the riser was analyzed and the results and the agreement with literature were discussed. The adopt model was validated under the MEF operational conditions, for a 3 to 6 m/s gas velocity in the riser and a slip

  8. Suitability of parametric models to describe the hydraulic properties of an unsaturated coarse sand and gravel

    Science.gov (United States)

    Mace, Andy; Rudolph, David L.; Kachanoski , R. Gary

    1998-01-01

    The performance of parametric models used to describe soil water retention (SWR) properties and predict unsaturated hydraulic conductivity (K) as a function of volumetric water content (θ) is examined using SWR and K(θ) data for coarse sand and gravel sediments. Six 70 cm long, 10 cm diameter cores of glacial outwash were instrumented at eight depths with porous cup ten-siometers and time domain reflectometry probes to measure soil water pressure head (h) and θ, respectively, for seven unsaturated and one saturated steady-state flow conditions. Forty-two θ(h) and K(θ) relationships were measured from the infiltration tests on the cores. Of the four SWR models compared in the analysis, the van Genuchten (1980) equation with parameters m and n restricted according to the Mualem (m = 1 - 1/n) criterion is best suited to describe the θ(h) relationships. The accuracy of two models that predict K(θ) using parameter values derived from the SWR models was also evaluated. The model developed by van Genuchten (1980) based on the theoretical expression of Mualem (1976) predicted K(θ) more accurately than the van Genuchten (1980) model based on the theory of Burdine (1953). A sensitivity analysis shows that more accurate predictions of K(θ) are achieved using SWR model parameters derived with residual water content (θr) specified according to independent measurements of θ at values of h where θ/h ∼ 0 rather than model-fit θr values. The accuracy of the model K(θ) function improves markedly when at least one value of unsaturated K is used to scale the K(θ) function predicted using the saturated K. The results of this investigation indicate that the hydraulic properties of coarse-grained sediments can be accurately described using the parametric models. In addition, data collection efforts should focus on measuring at least one value of unsaturated hydraulic conductivity and as complete a set of SWR data as possible, particularly in the dry range.

  9. A metallic solution model with adjustable parameter for describing ternary thermodynamic properties from its binary constituents

    International Nuclear Information System (INIS)

    Fang Zheng; Qiu Guanzhou

    2007-01-01

    A metallic solution model with adjustable parameter k has been developed to predict thermodynamic properties of ternary systems from those of its constituent three binaries. In the present model, the excess Gibbs free energy for a ternary mixture is expressed as a weighted probability sum of those of binaries and the k value is determined based on an assumption that the ternary interaction generally strengthens the mixing effects for metallic solutions with weak interaction, making the Gibbs free energy of mixing of the ternary system more negative than that before considering the interaction. This point is never considered in the models currently reported, where the only difference in a geometrical definition of molar values of components is considered that do not involve thermodynamic principles but are completely empirical. The current model describes the results of experiments very well, and by adjusting the k value also agrees with those from models used widely in the literature. Three ternary systems, Mg-Cu-Ni, Zn-In-Cd, and Cd-Bi-Pb are recalculated to demonstrate the method of determining k and the precision of the model. The results of the calculations, especially those in Mg-Cu-Ni system, are better than those predicted by the current models in the literature

  10. A model describing intra-granular fission gas behaviour in oxide fuel for advanced engineering tools

    Science.gov (United States)

    Pizzocri, D.; Pastore, G.; Barani, T.; Magni, A.; Luzzi, L.; Van Uffelen, P.; Pitts, S. A.; Alfonsi, A.; Hales, J. D.

    2018-04-01

    The description of intra-granular fission gas behaviour is a fundamental part of any model for the prediction of fission gas release and swelling in nuclear fuel. In this work we present a model describing the evolution of intra-granular fission gas bubbles in terms of bubble number density and average size, coupled to gas release to grain boundaries. The model considers the fundamental processes of single gas atom diffusion, gas bubble nucleation, re-solution and gas atom trapping at bubbles. The model is derived from a detailed cluster dynamics formulation, yet it consists of only three differential equations in its final form; hence, it can be efficiently applied in engineering fuel performance codes while retaining a physical basis. We discuss improvements relative to previous single-size models for intra-granular bubble evolution. We validate the model against experimental data, both in terms of bubble number density and average bubble radius. Lastly, we perform an uncertainty and sensitivity analysis by propagating the uncertainties in the parameters to model results.

  11. A bottom-up model to describe consumers’ preferences towards late season peaches

    Energy Technology Data Exchange (ETDEWEB)

    Groot, E.; Albisu, L.M.

    2015-07-01

    Peaches are consumed in Mediterranean countries since ancient times. Nowadays there are few areas in Europe that produce peaches with Protected Designation of Origin (PDO), and the Calanda area is one of them. The aim of this work is to describe consumers’ preferences towards late season PDO Calanda peaches in the city of Zaragoza, Spain, by a bottom-up model. The bottom-up model proves greater amount of information than top-down models. In this approach it is estimated one utility function per consumer. Thus, it is not necessary to make assumptions about preference distributions and correlations across respondents. It was observed that preference distributions were neither normal nor independently distributed. If those preferences were estimated by top-down models, conclusions would be biased. This paper also explores a new way to describe preferences through individual utility functions. Results show that the largest behavioural group gathered origin sensitive consumers. Their utility increased if the peaches were produced in the Calanda area and, especially, when peaches had the PDO Calanda brand. In sequence, the second most valuable attribute for consumers was the price. Peach size and packaging were not so important on purchase choice decision. Nevertheless, it is advisable to avoid trading smallest size peaches (weighting around 160 g/fruit). Traders also have to be careful by using active packaging. It was found that a group of consumers disliked this kind of product, probably, because they perceived it as less natural. (Author)

  12. Application of the International Water Association activated sludge models to describe aerobic sludge digestion.

    Science.gov (United States)

    Ghorbani, M; Eskicioglu, C

    2011-12-01

    Batch and semi-continuous flow aerobic digesters were used to stabilize thickened waste-activated sludge at different initial conditions and mean solids retention times. Under dynamic conditions, total suspended solids, volatile suspended solids (VSS) and total and particulate chemical oxygen demand (COD and PCOD) were monitored in the batch reactors and effluent from the semi-continuous flow reactors. Activated Sludge Model (ASM) no. 1 and ASM no. 3 were applied to measured data (calibration data set) to evaluate the consistency and performances of models at different flow regimes for digester COD and VSS modelling. The results indicated that both ASM1 and ASM3 predicted digester COD, VSS and PCOD concentrations well (R2, Ra2 > or = 0.93). Parameter estimation concluded that compared to ASM1, ASM3 parameters were more consistent across different batch and semi-continuous flow runs with different operating conditions. Model validation on a data set independent from the calibration data successfully predicted digester COD (R2 = 0.88) and VSS (R2 = 0.94) concentrations by ASM3, while ASM1 overestimated both reactor COD (R2 = 0.74) and VSS concentrations (R2 = 0.79) after 15 days of aerobic batch digestion.

  13. A Bayesian method for construction of Markov models to describe dynamics on various time-scales.

    Science.gov (United States)

    Rains, Emily K; Andersen, Hans C

    2010-10-14

    probable CMMM for the chosen mesoscopic time step. We applied this method of Markov model construction to several toy systems (random walks in one and two dimensions) as well as the dynamics of alanine dipeptide in water. The resulting Markov state models were indeed successful in capturing the dynamics of our test systems on a variety of mesoscopic time-scales.

  14. Digital Materials - Evaluation of the Possibilities of using Selected Hyperelastic Models to Describe Constitutive Relations

    Science.gov (United States)

    Mańkowski, J.; Lipnicki, J.

    2017-08-01

    The authors tried to identify the parameters of numerical models of digital materials, which are a kind of composite resulting from the manufacture of the product in 3D printers. With the arrangement of several heads of the printer, the new material can result from mixing of materials with radically different properties, during the process of producing single layer of the product. The new material has properties dependent on the base materials properties and their proportions. Digital materials tensile characteristics are often non-linear and qualify to be described by hyperelastic materials models. The identification was conducted based on the results of tensile tests models, its various degrees coefficients of the polynomials to various degrees coefficients of the polynomials. The Drucker's stability criterion was also examined. Fourteen different materials were analyzed.

  15. Digital Materials – Evaluation of the Possibilities of using Selected Hyperelastic Models to Describe Constitutive Relations

    Directory of Open Access Journals (Sweden)

    Mańkowski J.

    2017-08-01

    Full Text Available The authors tried to identify the parameters of numerical models of digital materials, which are a kind of composite resulting from the manufacture of the product in 3D printers. With the arrangement of several heads of the printer, the new material can result from mixing of materials with radically different properties, during the process of producing single layer of the product. The new material has properties dependent on the base materials properties and their proportions. Digital materials tensile characteristics are often non-linear and qualify to be described by hyperelastic materials models. The identification was conducted based on the results of tensile tests models, its various degrees coefficients of the polynomials to various degrees coefficients of the polynomials. The Drucker’s stability criterion was also examined. Fourteen different materials were analyzed.

  16. Ordinal regression models to describe tourist satisfaction with Sintra's world heritage

    Science.gov (United States)

    Mouriño, Helena

    2013-10-01

    In Tourism Research, ordinal regression models are becoming a very powerful tool in modelling the relationship between an ordinal response variable and a set of explanatory variables. In August and September 2010, we conducted a pioneering Tourist Survey in Sintra, Portugal. The data were obtained by face-to-face interviews at the entrances of the Palaces and Parks of Sintra. The work developed in this paper focus on two main points: tourists' perception of the entrance fees; overall level of satisfaction with this heritage site. For attaining these goals, ordinal regression models were developed. We concluded that tourist's nationality was the only significant variable to describe the perception of the admission fees. Also, Sintra's image among tourists depends not only on their nationality, but also on previous knowledge about Sintra's World Heritage status.

  17. Computational Models Describing Possible Mechanisms for Generation of Excessive Beta Oscillations in Parkinson's Disease.

    Directory of Open Access Journals (Sweden)

    Alex Pavlides

    2015-12-01

    Full Text Available In Parkinson's disease, an increase in beta oscillations within the basal ganglia nuclei has been shown to be associated with difficulty in movement initiation. An important role in the generation of these oscillations is thought to be played by the motor cortex and by a network composed of the subthalamic nucleus (STN and the external segment of globus pallidus (GPe. Several alternative models have been proposed to describe the mechanisms for generation of the Parkinsonian beta oscillations. However, a recent experimental study of Tachibana and colleagues yielded results which are challenging for all published computational models of beta generation. That study investigated how the presence of beta oscillations in a primate model of Parkinson's disease is affected by blocking different connections of the STN-GPe circuit. Due to a large number of experimental conditions, the study provides strong constraints that any mechanistic model of beta generation should satisfy. In this paper we present two models consistent with the data of Tachibana et al. The first model assumes that Parkinsonian beta oscillation are generated in the cortex and the STN-GPe circuits resonates at this frequency. The second model additionally assumes that the feedback from STN-GPe circuit to cortex is important for maintaining the oscillations in the network. Predictions are made about experimental evidence that is required to differentiate between the two models, both of which are able to reproduce firing rates, oscillation frequency and effects of lesions carried out by Tachibana and colleagues. Furthermore, an analysis of the models reveals how the amplitude and frequency of the generated oscillations depend on parameters.

  18. Development of a geometric uncertainty model describing the accuracy of position-sensitive, coincidence neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Trivelpiece, Cory L., E-mail: cory@psu.ed [Department of Mechanical and Nuclear Engineering, The Pennsylvania, State University, University Park, PA 16802 (United States); Brenizer, J.S. [Department of Mechanical and Nuclear Engineering, The Pennsylvania, State University, University Park, PA 16802 (United States)

    2011-01-01

    A diameter of uncertainty (D{sub u}) was derived from a geometric uncertainty model describing the error that would be introduced into position-sensitive, coincidence neutron detection measurements by charged-particle transport phenomena and experimental setup. The transport of {alpha} and Li ions, produced by the {sup 10}B(n,{alpha}) {sup 7}Li reaction, through free-standing boro-phosphosilicate glass (BPSG) films was modeled using the Monte Carlo code SRIM, and the results of these simulations were used as input to determine D{sub u} for position-sensitive, coincidence techniques. The results of these calculations showed that D{sub u} is dependent on encoder separation, the angle of charged particle emission, and film thickness. For certain emission scenarios, the magnitude of D{sub u} is larger than the physical size of the neutron converting media that were being modeled. Spheres of uncertainty were developed that describe the difference in flight path times among the bounding-case emission scenarios that were considered in this work. It was shown the overlapping spheres represent emission angles and particle flight path lengths that would be difficult to resolve in terms of particle time-of-flight measurements. However, based on the timing resolution of current nuclear instrumentation, emission events that yield large D{sub u} can be discriminated by logical arguments during spectral deconvolution.

  19. Development of the model describing highly excited states of odd deformed nuclei

    International Nuclear Information System (INIS)

    Malov, L.A.; Solov'ev, V.G.

    1975-01-01

    An approximate method is given for solving the system of equations obtained earlier for describing the structure of states with intermediate and high energies in the framework of the model taking into account the interaction of quasiparticles with phonons. The new method possesses a number of advantages over the approximate methods of solving the system of equations mentioned. The study is performed for the example of an odd deformed nucleus when several one-quasiparticle components are taken into account at the same time

  20. Critical properties of a ferroelectric superlattice described by a transverse spin-1/2 Ising model

    International Nuclear Information System (INIS)

    Tabyaoui, A; Saber, M; Baerner, K; Ainane, A

    2007-01-01

    The phase transition properties of a ferroelectric superlattice with two alternating layers A and B described by a transverse spin-1/2 Ising model have been investigated using the effective field theory within a probability distribution technique that accounts for the self spin correlation functions. The Curie temperature T c , polarization and susceptibility have been obtained. The effects of the transverse field and the ferroelectric and antiferroelectric interfacial coupling strength between two ferroelectric materials are discussed. They relate to the physical properties of antiferroelectric/ferroelectric superlattices

  1. Model describing the effect of employment of the United States military in a complex emergency.

    Science.gov (United States)

    MacMillan, Donald S

    2005-01-01

    The end of the Cold War vastly altered the worldwide political landscape. With the loss of a main competitor, the United States (US) military has had to adapt its strategic, operational, and tactical doctrines to an ever-increasing variety of non-traditional missions, including humanitarian operations. Complex emergencies (CEs) are defined in this paper from a political and military perspective, various factors that contribute to their development are described, and issues resulting from the employment of US military forces are discussed. A model was developed to illustrate the course of a humanitarian emergency and the potential impact of a military response. The US intervention in Haiti, Northern Iraq, Kosovo, Somalia, Bosnia, and Rwanda serve as examples. A CE develops when there is civil conflict, loss of national governmental authority, a mass population movement, and massive economic failure, each leading to a general decline in food security. The military can alleviate a CE in four ways: (1) provide security for relief efforts; (2) enforce negotiated settlements; (3) provide security for non-combatants; and/or (4) employ logistical capabilities. The model incorporates Norton and Miskel's taxonomy of identifying failing states and helps illustrate the factors that lead to a CE. The model can be used to determine if and when military intervention will have the greatest impact. The model demonstrates that early military intervention and mission assignment within the core competencies of the forces can reverse the course of a CE. Further study will be needed to verify the model.

  2. A flowing plasma model to describe drift waves in a cylindrical helicon discharge

    International Nuclear Information System (INIS)

    Chang, L.; Hole, M. J.; Corr, C. S.

    2011-01-01

    A two-fluid model developed originally to describe wave oscillations in the vacuum arc centrifuge, a cylindrical, rapidly rotating, low temperature, and confined plasma column, is applied to interpret plasma oscillations in a RF generated linear magnetized plasma [WOMBAT (waves on magnetized beams and turbulence)], with similar density and field strength. Compared to typical centrifuge plasmas, WOMBAT plasmas have slower normalized rotation frequency, lower temperature, and lower axial velocity. Despite these differences, the two-fluid model provides a consistent description of the WOMBAT plasma configuration and yields qualitative agreement between measured and predicted wave oscillation frequencies with axial field strength. In addition, the radial profile of the density perturbation predicted by this model is consistent with the data. Parameter scans show that the dispersion curve is sensitive to the axial field strength and the electron temperature, and the dependence of oscillation frequency with electron temperature matches the experiment. These results consolidate earlier claims that the density and floating potential oscillations are a resistive drift mode, driven by the density gradient. To our knowledge, this is the first detailed physics model of flowing plasmas in the diffusion region away from the RF source. Possible extensions to the model, including temperature nonuniformity and magnetic field oscillations, are also discussed.

  3. Application of a mathematical model to describe the effects of chlorpyrifos on Caenorhabditis elegans development.

    Directory of Open Access Journals (Sweden)

    Windy A Boyd

    2009-09-01

    Full Text Available The nematode Caenorhabditis elegans is being assessed as an alternative model organism as part of an interagency effort to develop better means to test potentially toxic substances. As part of this effort, assays that use the COPAS Biosort flow sorting technology to record optical measurements (time of flight (TOF and extinction (EXT of individual nematodes under various chemical exposure conditions are being developed. A mathematical model has been created that uses Biosort data to quantitatively and qualitatively describe C. elegans growth, and link changes in growth rates to biological events. Chlorpyrifos, an organophosphate pesticide known to cause developmental delays and malformations in mammals, was used as a model toxicant to test the applicability of the growth model for in vivo toxicological testing.L1 larval nematodes were exposed to a range of sub-lethal chlorpyrifos concentrations (0-75 microM and measured every 12 h. In the absence of toxicant, C. elegans matured from L1s to gravid adults by 60 h. A mathematical model was used to estimate nematode size distributions at various times. Mathematical modeling of the distributions allowed the number of measured nematodes and log(EXT and log(TOF growth rates to be estimated. The model revealed three distinct growth phases. The points at which estimated growth rates changed (change points were constant across the ten chlorpyrifos concentrations. Concentration response curves with respect to several model-estimated quantities (numbers of measured nematodes, mean log(TOF and log(EXT, growth rates, and time to reach change points showed a significant decrease in C. elegans growth with increasing chlorpyrifos concentration.Effects of chlorpyrifos on C. elegans growth and development were mathematically modeled. Statistical tests confirmed a significant concentration effect on several model endpoints. This confirmed that chlorpyrifos affects C. elegans development in a concentration dependent

  4. Cosmological models described by a mixture of van der Waals fluid and dark energy

    International Nuclear Information System (INIS)

    Kremer, G.M.

    2003-01-01

    The Universe is modeled as a binary mixture whose constituents are described by a van der Waals fluid and by a dark energy density. The dark energy density is considered either as quintessence or as the Chaplygin gas. The irreversible processes concerning the energy transfer between the van der Waals fluid and the gravitational field are taken into account. This model can simulate (a) an inflationary period where the acceleration grows exponentially and the van der Waals fluid behaves like an inflaton, (b) an accelerated period where the acceleration is positive but it decreases and tends to zero whereas the energy density of the van der Waals fluid decays, (c) a decelerated period which corresponds to a matter dominated period with a non-negative pressure, and (d) a present accelerated period where the dark energy density outweighs the energy density of the van der Waals fluid

  5. The solar modulation of galactic comic rays as described by a time-dependent drift model

    International Nuclear Information System (INIS)

    Le Roux, J.A.

    1990-09-01

    The modulation process is understood to be an interaction between cosmic rays and the solar wind. The heliosphere and the observed modulation of cosmic rays in the heliosphere was reviewed and the time-dependence nature of the long-term modulation of cosmic rays highligted. A two-dimensional time-dependent drift model that describes the long-term modulation of cosmic-rays is presented. Application of the time-dependent drift model during times of increased solar activity showed that drift should be reduced during such periods. Isolated Forbush decreases were also studied in an effort to explain some observed trends in the properties of the Forbush decrease as a function of radial distance. The magnitude of the Forbush decrease and its recovery time were therefore studied as a function of radial distance in the equatorial plane. 154 refs., 95 figs., 1 tab

  6. Generating quantitative models describing the sequence specificity of biological processes with the stabilized matrix method

    Directory of Open Access Journals (Sweden)

    Sette Alessandro

    2005-05-01

    Full Text Available Abstract Background Many processes in molecular biology involve the recognition of short sequences of nucleic-or amino acids, such as the binding of immunogenic peptides to major histocompatibility complex (MHC molecules. From experimental data, a model of the sequence specificity of these processes can be constructed, such as a sequence motif, a scoring matrix or an artificial neural network. The purpose of these models is two-fold. First, they can provide a summary of experimental results, allowing for a deeper understanding of the mechanisms involved in sequence recognition. Second, such models can be used to predict the experimental outcome for yet untested sequences. In the past we reported the development of a method to generate such models called the Stabilized Matrix Method (SMM. This method has been successfully applied to predicting peptide binding to MHC molecules, peptide transport by the transporter associated with antigen presentation (TAP and proteasomal cleavage of protein sequences. Results Herein we report the implementation of the SMM algorithm as a publicly available software package. Specific features determining the type of problems the method is most appropriate for are discussed. Advantageous features of the package are: (1 the output generated is easy to interpret, (2 input and output are both quantitative, (3 specific computational strategies to handle experimental noise are built in, (4 the algorithm is designed to effectively handle bounded experimental data, (5 experimental data from randomized peptide libraries and conventional peptides can easily be combined, and (6 it is possible to incorporate pair interactions between positions of a sequence. Conclusion Making the SMM method publicly available enables bioinformaticians and experimental biologists to easily access it, to compare its performance to other prediction methods, and to extend it to other applications.

  7. Double porosity model to describe both permeability change and dissolution processes

    International Nuclear Information System (INIS)

    Niibori, Yuichi; Usui, Hideo; Chida, Taiji

    2015-01-01

    Cement is a practical material for constructing the geological disposal system of radioactive wastes. The dynamic behavior of both permeability change and dissolution process caused by a high pH groundwater was explained using a double porosity model assuming that each packed particle consists of the sphere-shaped aggregation of smaller particles. This model assumes two kinds of porosities between the particle clusters and between the particles, where the former porosity change mainly controls the permeability change of the bed, and the latter porosity change controls the diffusion of OH"- ions inducing the dissolution of silica. The fundamental equations consist of a diffusion equation of spherical coordinates of OH"- ions including the first-order reaction term and some equations describing the size changes of both the particles and the particle clusters with time. The change of over-all permeability of the packed bed is evaluated by Kozeny-Carman equation and the calculated radii of particle clusters. The calculated result well describes the experimental result of both permeability change and dissolution processes. (author)

  8. A mathematical model for describing the mechanical behaviour of root canal instruments.

    Science.gov (United States)

    Zhang, E W; Cheung, G S P; Zheng, Y F

    2011-01-01

    The purpose of this study was to establish a general mathematical model for describing the mechanical behaviour of root canal instruments by combining a theoretical analytical approach with a numerical finite-element method. Mathematical formulas representing the longitudinal (taper, helical angle and pitch) and cross-sectional configurations and area, the bending and torsional inertia, the curvature of the boundary point and the (geometry of) loading condition were derived. Torsional and bending stresses and the resultant deformation were expressed mathematically as a function of these geometric parameters, modulus of elasticity of the material and the applied load. As illustrations, three brands of NiTi endodontic files of different cross-sectional configurations (ProTaper, Hero 642, and Mani NRT) were analysed under pure torsion and pure bending situation by entering the model into a finite-element analysis package (ANSYS). Numerical results confirmed that mathematical models were a feasible method to analyse the mechanical properties and predict the stress and deformation for root canal instruments during root canal preparation. Mathematical and numerical model can be a suitable way to examine mechanical behaviours as a criterion of the instrument design and to predict the stress and strain experienced by the endodontic instruments during root canal preparation. © 2010 International Endodontic Journal.

  9. Cosmological model with viscosity media (dark fluid) described by an effective equation of state

    International Nuclear Information System (INIS)

    Ren Jie; Meng Xinhe

    2006-01-01

    A generally parameterized equation of state (EOS) is investigated in the cosmological evolution with bulk viscosity media modelled as dark fluid, which can be regarded as a unification of dark energy and dark matter. Compared with the case of the perfect fluid, this EOS has possessed four additional parameters, which can be interpreted as the case of the non-perfect fluid with time-dependent viscosity or the model with variable cosmological constant. From this general EOS, a completely integrable dynamical equation to the scale factor is obtained with its solution explicitly given out. (i) In this parameterized model of cosmology, for a special choice of the parameters we can explain the late-time accelerating expansion universe in a new view. The early inflation, the median (relatively late time) deceleration, and the recently cosmic acceleration may be unified in a single equation. (ii) A generalized relation of the Hubble parameter scaling with the redshift is obtained for some cosmology interests. (iii) By using the SNe Ia data to fit the effective viscosity model we show that the case of matter described by p=0 plus with effective viscosity contributions can fit the observational gold data in an acceptable level

  10. Prediction models for successful external cephalic version: a systematic review.

    Science.gov (United States)

    Velzel, Joost; de Hundt, Marcella; Mulder, Frederique M; Molkenboer, Jan F M; Van der Post, Joris A M; Mol, Ben W; Kok, Marjolein

    2015-12-01

    To provide an overview of existing prediction models for successful ECV, and to assess their quality, development and performance. We searched MEDLINE, EMBASE and the Cochrane Library to identify all articles reporting on prediction models for successful ECV published from inception to January 2015. We extracted information on study design, sample size, model-building strategies and validation. We evaluated the phases of model development and summarized their performance in terms of discrimination, calibration and clinical usefulness. We collected different predictor variables together with their defined significance, in order to identify important predictor variables for successful ECV. We identified eight articles reporting on seven prediction models. All models were subjected to internal validation. Only one model was also validated in an external cohort. Two prediction models had a low overall risk of bias, of which only one showed promising predictive performance at internal validation. This model also completed the phase of external validation. For none of the models their impact on clinical practice was evaluated. The most important predictor variables for successful ECV described in the selected articles were parity, placental location, breech engagement and the fetal head being palpable. One model was assessed using discrimination and calibration using internal (AUC 0.71) and external validation (AUC 0.64), while two other models were assessed with discrimination and calibration, respectively. We found one prediction model for breech presentation that was validated in an external cohort and had acceptable predictive performance. This model should be used to council women considering ECV. Copyright © 2015. Published by Elsevier Ireland Ltd.

  11. Species-free species distribution models describe macroecological properties of protected area networks.

    Science.gov (United States)

    Robinson, Jason L; Fordyce, James A

    2017-01-01

    Among the greatest challenges facing the conservation of plants and animal species in protected areas are threats from a rapidly changing climate. An altered climate creates both challenges and opportunities for improving the management of protected areas in networks. Increasingly, quantitative tools like species distribution modeling are used to assess the performance of protected areas and predict potential responses to changing climates for groups of species, within a predictive framework. At larger geographic domains and scales, protected area network units have spatial geoclimatic properties that can be described in the gap analysis typically used to measure or aggregate the geographic distributions of species (stacked species distribution models, or S-SDM). We extend the use of species distribution modeling techniques in order to model the climate envelope (or "footprint") of individual protected areas within a network of protected areas distributed across the 48 conterminous United States and managed by the US National Park System. In our approach we treat each protected area as the geographic range of a hypothetical endemic species, then use MaxEnt and 5 uncorrelated BioClim variables to model the geographic distribution of the climatic envelope associated with each protected area unit (modeling the geographic area of park units as the range of a species). We describe the individual and aggregated climate envelopes predicted by a large network of 163 protected areas and briefly illustrate how macroecological measures of geodiversity can be derived from our analysis of the landscape ecological context of protected areas. To estimate trajectories of change in the temporal distribution of climatic features within a protected area network, we projected the climate envelopes of protected areas in current conditions onto a dataset of predicted future climatic conditions. Our results suggest that the climate envelopes of some parks may be locally unique or have

  12. Methodological Bases for Describing Risks of the Enterprise Business Model in Integrated Reporting

    Directory of Open Access Journals (Sweden)

    Nesterenko Oksana O.

    2017-12-01

    Full Text Available The aim of the article is to substantiate the methodological bases for describing the business and accounting risks of an enterprise business model in integrated reporting for their timely detection and assessment, and develop methods for their leveling or minimizing and possible prevention. It is proposed to consider risks in the process of forming integrated reporting from two sides: first, risks that arise in the business model of an organization and should be disclosed in its integrated report; second, accounting risks of integrated reporting, which should be taken into account by members of the cross-sectoral working group and management personnel in the process of forming and promulgating integrated reporting. To develop an adequate accounting and analytical tool for disclosure of information about the risks of the business model and integrated reporting, their leveling or minimization, in the article a terminological analysis of the essence of entrepreneurial and accounting risks is carried out. The entrepreneurial risk is defined as an objective-subjective economic category that characterizes the probability of negative or positive consequences of economic-social-ecological activity within the framework of the business model of an enterprise under uncertainty. The accounting risk is suggested to be understood as the probability of unfavorable consequences as a result of organizational, methodological errors in the integrated accounting system, which present threat to the quality, accuracy and reliability of the reporting information on economic, social and environmental activities in integrated reporting as well as threat of inappropriate decision-making by stakeholders based on the integrated report. For the timely identification of business risks and maximum leveling of the influence of accounting risks on the process of formation and publication of integrated reporting, in the study the place of entrepreneurial and accounting risks in

  13. Model tool to describe chemical structures in XML format utilizing structural fragments and chemical ontology.

    Science.gov (United States)

    Sankar, Punnaivanam; Alain, Krief; Aghila, Gnanasekaran

    2010-05-24

    We have developed a model structure-editing tool, ChemEd, programmed in JAVA, which allows drawing chemical structures on a graphical user interface (GUI) by selecting appropriate structural fragments defined in a fragment library. The terms representing the structural fragments are organized in fragment ontology to provide a conceptual support. ChemEd describes the chemical structure in an XML document (ChemFul) with rich semantics explicitly encoding the details of the chemical bonding, the hybridization status, and the electron environment around each atom. The document can be further processed through suitable algorithms and with the support of external chemical ontologies to generate understandable reports about the functional groups present in the structure and their specific environment.

  14. Computer-aided Nonlinear Control System Design Using Describing Function Models

    CERN Document Server

    Nassirharand, Amir

    2012-01-01

    A systematic computer-aided approach provides a versatile setting for the control engineer to overcome the complications of controller design for highly nonlinear systems. Computer-aided Nonlinear Control System Design provides such an approach based on the use of describing functions. The text deals with a large class of nonlinear systems without restrictions on the system order, the number of inputs and/or outputs or the number, type or arrangement of nonlinear terms. The strongly software-oriented methods detailed facilitate fulfillment of tight performance requirements and help the designer to think in purely nonlinear terms, avoiding the expedient of linearization which can impose substantial and unrealistic model limitations and drive up the cost of the final product. Design procedures are presented in a step-by-step algorithmic format each step being a functional unit with outputs that drive the other steps. This procedure may be easily implemented on a digital computer with example problems from mecha...

  15. Regression models describing Rosa hybrida response to day/night temperature and photosynthetic photon flux

    International Nuclear Information System (INIS)

    Hopper, D.A.; Hammer, P.A.

    1991-01-01

    A central composite rotatable design was used to estimate quadratic equations describing the relationship of irradiance, as measured by photosynthetic photon flux (PPF), and day (DT) and night (NT) temperatures to the growth and development of Rosa hybrida L. in controlled environments. Plants were subjected to 15 treatment combinations of the PPF, DT, and NT according to the coding of the design matrix. Day and night length were each 12 hours. Environmental factor ranges were chosen to include conditions representative of winter and spring commercial greenhouse production environments in the midwestern United States. After an initial hard pinch, 11 plant growth characteristics were measured every 10 days and at flowering. Four plant characteristics were recorded to describe flower bud development. Response surface equations were displayed as three-dimensional plots, with DT and NT as the base axes and the plant character on the z-axis while PPF was held constant. Response surfaces illustrated the plant response to interactions of DT and NT, while comparisons between plots at different PPF showed the overall effect of PPF. Canonical analysis of all regression models revealed the stationary point and general shape of the response surface. All stationary points of the significant models were located outside the original design space, and all but one surface was a saddle shape. Both the plots and analysis showed greater stem diameter, as well as higher fresh and dry weights of stems, leaves, and flower buds to occur at flowering under combinations of low DT (less than or equal to 17C) and low NT (less than or equal to 14C). However, low DT and NT delayed both visible bud formation and development to flowering. Increased PPF increased overall flower stem quality by increasing stem diameter and the fresh and dry weights of all plant parts at flowering, as well as decreased time until visible bud formation and flowering. These results summarize measured development at

  16. Inclusion of models to describe severe accident conditions in the fuel simulation code DIONISIO

    Energy Technology Data Exchange (ETDEWEB)

    Lemes, Martín; Soba, Alejandro [Sección Códigos y Modelos, Gerencia Ciclo del Combustible Nuclear, Comisión Nacional de Energía Atómica, Avenida General Paz 1499, 1650 San Martín, Provincia de Buenos Aires (Argentina); Daverio, Hernando [Gerencia Reactores y Centrales Nucleares, Comisión Nacional de Energía Atómica, Avenida General Paz 1499, 1650 San Martín, Provincia de Buenos Aires (Argentina); Denis, Alicia [Sección Códigos y Modelos, Gerencia Ciclo del Combustible Nuclear, Comisión Nacional de Energía Atómica, Avenida General Paz 1499, 1650 San Martín, Provincia de Buenos Aires (Argentina)

    2017-04-15

    The simulation of fuel rod behavior is a complex task that demands not only accurate models to describe the numerous phenomena occurring in the pellet, cladding and internal rod atmosphere but also an adequate interconnection between them. In the last years several models have been incorporated to the DIONISIO code with the purpose of increasing its precision and reliability. After the regrettable events at Fukushima, the need for codes capable of simulating nuclear fuels under accident conditions has come forth. Heat removal occurs in a quite different way than during normal operation and this fact determines a completely new set of conditions for the fuel materials. A detailed description of the different regimes the coolant may exhibit in such a wide variety of scenarios requires a thermal-hydraulic formulation not suitable to be included in a fuel performance code. Moreover, there exist a number of reliable and famous codes that perform this task. Nevertheless, and keeping in mind the purpose of building a code focused on the fuel behavior, a subroutine was developed for the DIONISIO code that performs a simplified analysis of the coolant in a PWR, restricted to the more representative situations and provides to the fuel simulation the boundary conditions necessary to reproduce accidental situations. In the present work this subroutine is described and the results of different comparisons with experimental data and with thermal-hydraulic codes are offered. It is verified that, in spite of its comparative simplicity, the predictions of this module of DIONISIO do not differ significantly from those of the specific, complex codes.

  17. Theoretical models for describing longitudinal bunch compression in the neutralized drift compression experiment

    Directory of Open Access Journals (Sweden)

    Adam B. Sefkow

    2006-09-01

    Full Text Available Heavy ion drivers for warm dense matter and heavy ion fusion applications use intense charge bunches which must undergo transverse and longitudinal compression in order to meet the requisite high current densities and short pulse durations desired at the target. The neutralized drift compression experiment (NDCX at the Lawrence Berkeley National Laboratory is used to study the longitudinal neutralized drift compression of a space-charge-dominated ion beam, which occurs due to an imposed longitudinal velocity tilt and subsequent neutralization of the beam’s space charge by background plasma. Reduced theoretical models have been used in order to describe the realistic propagation of an intense charge bunch through the NDCX device. A warm-fluid model is presented as a tractable computational tool for investigating the nonideal effects associated with the experimental acceleration gap geometry and voltage waveform of the induction module, which acts as a means to pulse shape both the velocity and line density profiles. Self-similar drift compression solutions can be realized in order to transversely focus the entire charge bunch to the same focal plane in upcoming simultaneous transverse and longitudinal focusing experiments. A kinetic formalism based on the Vlasov equation has been employed in order to show that the peaks in the experimental current profiles are a result of the fact that only the central portion of the beam contributes effectively to the main compressed pulse. Significant portions of the charge bunch reside in the nonlinearly compressing part of the ion beam because of deviations between the experimental and ideal velocity tilts. Those regions form a pedestal of current around the central peak, thereby decreasing the amount of achievable longitudinal compression and increasing the pulse durations achieved at the focal plane. A hybrid fluid-Vlasov model which retains the advantages of both the fluid and kinetic approaches has been

  18. A unified model to describe the anisotropic viscoplastic behavior of Zircaloy-4 cladding tubes

    International Nuclear Information System (INIS)

    Delobelle, P.; Robinet, P.; Bouffioux, P.; Geyer, P.; Pichon, I. Le

    1996-01-01

    This paper presents the constitutive equations of a unified viscoplastic model and its validation with experimental data. The mechanical tests were carried out in a temperature range of 20 to 400 C on both cold-worked stress-relieved and fully annealed Zircaloy-4 tubes. Although their geometry (14.3 by 1.2 mm) is different, the crystallographic texture was close to that expected in the cladding tubes. To characterize the anisotropy, mechanical tests were performed under both monotonic and cyclic uni- and bi-directional loadings, i.e., tension-compression, tension-torsion, and tension-internal pressure tests. The results obtained at ambient temperatures and the independence of the ratio R p = var-epsilon θθ p /var-epsilon zz p , with respect to temperature would seem to indicate that the set of anisotropy coefficients does not depend on temperature. Zircaloy-4 material also has a slight supplementary hardening during out-of-phase cyclic loading. The authors propose to extend the formulation of a unified viscoplastic model, developed and identified elsewhere for other initially isotropic materials, to the case of Zircaloy-4. Generally speaking, anisotropy is introduced through fourth order tensors affecting the flow directions, the linear kinematical hardening components, as well as the dynamic and static recoveries of the forementioned hardening variables. The ability of the model to describe all the mechanical properties of the material is shown. The application of the model to simulate mechanical tests (tension, creep, and relaxation) performed on true CWSR Zircaloy-4 cladding tubes with low tin content is also presented

  19. Comparison of three nonlinear models to describe long-term tag shedding by lake trout

    Science.gov (United States)

    Fabrizio, Mary C.; Swanson, Bruce L.; Schram, Stephen T.; Hoff, Michael H.

    1996-01-01

    We estimated long-term tag-shedding rates for lake trout Salvelinus namaycush using two existing models and a model we developed to account for the observed permanence of some tags. Because tag design changed over the course of the study, we examined tag-shedding rates for three types of numbered anchor tags (Floy tags FD-67, FD-67C, and FD-68BC) and an unprinted anchor tag (FD-67F). Lake trout from the Gull Island Shoal region, Lake Superior, were double-tagged, and subsequent recaptures were monitored in annual surveys conducted from 1974 to 1992. We modeled tag-shedding rates, using time at liberty and probabilities of tag shedding estimated from fish released in 1974 and 1978–1983 and later recaptured. Long-term shedding of numbered anchor tags in lake trout was best described by a nonlinear model with two parameters: an instantaneous tag-shedding rate and a constant representing the proportion of tags that were never shed. Although our estimates of annual shedding rates varied with tag type (0.300 for FD-67, 0.441 for FD-67C, and 0.656 for FD-68BC), differences were not significant. About 36% of tags remained permanently affixed to the fish. Of the numbered tags that were shed (about 64%), two mechanisms contributed to tag loss: disintegration and dislodgment. Tags from about 11% of recaptured fish had disintegrated, but most tags were dislodged. Unprinted tags were shed at a significant but low rate immediately after release, but the long-term, annual shedding rate of these tags was only 0.013. Compared with unprinted tags, numbered tags dislodged at higher annual rates; we hypothesized that this was due to the greater frictional drag associated with the larger cross-sectional area of numbered tags.

  20. Can a Linear Sigma Model Describe Walking Gauge Theories at Low Energies?

    Science.gov (United States)

    Gasbarro, Andrew

    2018-03-01

    In recent years, many investigations of confining Yang Mills gauge theories near the edge of the conformal window have been carried out using lattice techniques. These studies have revealed that the spectrum of hadrons in nearly conformal ("walking") gauge theories differs significantly from the QCD spectrum. In particular, a light singlet scalar appears in the spectrum which is nearly degenerate with the PNGBs at the lightest currently accessible quark masses. This state is a viable candidate for a composite Higgs boson. Presently, an acceptable effective field theory (EFT) description of the light states in walking theories has not been established. Such an EFT would be useful for performing chiral extrapolations of lattice data and for serving as a bridge between lattice calculations and phenomenology. It has been shown that the chiral Lagrangian fails to describe the IR dynamics of a theory near the edge of the conformal window. Here we assess a linear sigma model as an alternate EFT description by performing explicit chiral fits to lattice data. In a combined fit to the Goldstone (pion) mass and decay constant, a tree level linear sigma model has a Χ2/d.o.f. = 0.5 compared to Χ2/d.o.f. = 29.6 from fitting nextto-leading order chiral perturbation theory. When the 0++ (σ) mass is included in the fit, Χ2/d.o.f. = 4.9. We remark on future directions for providing better fits to the σ mass.

  1. A Minimal Model Describing Hexapedal Interlimb Coordination: The Tegotae-Based Approach

    Directory of Open Access Journals (Sweden)

    Dai Owaki

    2017-06-01

    Full Text Available Insects exhibit adaptive and versatile locomotion despite their minimal neural computing. Such locomotor patterns are generated via coordination between leg movements, i.e., an interlimb coordination, which is largely controlled in a distributed manner by neural circuits located in thoracic ganglia. However, the mechanism responsible for the interlimb coordination still remains elusive. Understanding this mechanism will help us to elucidate the fundamental control principle of animals' agile locomotion and to realize robots with legs that are truly adaptive and could not be developed solely by conventional control theories. This study aims at providing a “minimal" model of the interlimb coordination mechanism underlying hexapedal locomotion, in the hope that a single control principle could satisfactorily reproduce various aspects of insect locomotion. To this end, we introduce a novel concept we named “Tegotae,” a Japanese concept describing the extent to which a perceived reaction matches an expectation. By using the Tegotae-based approach, we show that a surprisingly systematic design of local sensory feedback mechanisms essential for the interlimb coordination can be realized. We also use a hexapod robot we developed to show that our mathematical model of the interlimb coordination mechanism satisfactorily reproduces various insects' gait patterns.

  2. Fast fission phenomenon, deep inelastic reactions and compound nucleus formation described within a dynamical macroscopic model

    International Nuclear Information System (INIS)

    Gregoire, C.; Ngo, C.; Remaud, B.

    1982-01-01

    We present a dynamical model to describe dissipative heavy ion reactions. It treats explicitly the relative motion of the two ions, the mass asymmetry of the system and the projection of the isospin of each ion. The deformations, which are induced during the collision, are simulated with a time-dependent interaction potential. This is done by a time-dependent transition between a sudden interaction potential in the entrance channel and an adiabatic potential in the exit channel. The model allows us to compute the compound-nucleus cross section and multidifferential cross-sections for deep inelastic reactions. In addition, for some systems, and under certain conditions which are discussed in detail, a new dissipative heavy ion collision appears: fast-fission phenomenon which has intermediate properties between deep inelastic and compound nucleus reactions. The calculated properties concerning fast fission are compared with experimental results and reproduce some of those which could not be understood as belonging to deep inelastic or compound-nucleus reactions. (orig.)

  3. Pharmacodynamic Model To Describe the Concentration-Dependent Selection of Cefotaxime-Resistant Escherichia coli

    Science.gov (United States)

    Olofsson, Sara K.; Geli, Patricia; Andersson, Dan I.; Cars, Otto

    2005-01-01

    Antibiotic dosing regimens may vary in their capacity to select mutants. Our hypothesis was that selection of a more resistant bacterial subpopulation would increase with the time within a selective window (SW), i.e., when drug concentrations fall between the MICs of two strains. An in vitro kinetic model was used to study the selection of two Escherichia coli strains with different susceptibilities to cefotaxime. The bacterial mixtures were exposed to cefotaxime for 24 h and SWs of 1, 2, 4, 8, and 12 h. A mathematical model was developed that described the selection of preexisting and newborn mutants and the post-MIC effect (PME) as functions of pharmacokinetic parameters. Our main conclusions were as follows: (i) the selection between preexisting mutants increased with the time within the SW; (ii) the emergence and selection of newborn mutants increased with the time within the SW (with a short time, only 4% of the preexisting mutants were replaced by newborn mutants, compared to the longest times, where 100% were replaced); and (iii) PME increased with the area under the concentration-time curve (AUC) and was slightly more pronounced with a long elimination half-life (T1/2) than with a short T1/2 situation, when AUC is fixed. We showed that, in a dynamic competition between strains with different levels of resistance, the appearance of newborn high-level resistant mutants from the parental strains and the PME can strongly affect the outcome of the selection and that pharmacodynamic models can be used to predict the outcome of resistance development. PMID:16304176

  4. Ecohydrology in Mediterranean areas: a numerical model to describe growing seasons out of phase with precipitations

    Directory of Open Access Journals (Sweden)

    D. Pumo

    2008-02-01

    Full Text Available The probabilistic description of soil moisture dynamics is a relatively new topic in hydrology. The most common ecohydrological models start from a stochastic differential equation describing the soil water balance, where the unknown quantity, the soil moisture, depends both on spaces and time. Most of the solutions existing in literature are obtained in a probabilistic framework and under steady-state condition; even if this last condition allows the analytical handling of the problem, it has considerably simplified the same problem by subtracting generalities from it.

    The steady-state hypothesis, appears perfectly applicable in arid and semiarid climatic areas like those of African's or middle American's savannas, but it seems to be no more valid in areas with Mediterranean climate, where, notoriously, the wet season foregoes the growing season, recharging water into the soil. This moisture stored at the beginning of the growing season (known as soil moisture initial condition has a great importance, especially for deep-rooted vegetation, by enabling survival in absence of rainfalls during the growing season and, however, keeping the water stress low during the first period of the same season.

    The aim of this paper is to analyze the soil moisture dynamics using a simple non-steady numerical ecohydrological model. The numerical model here proposed is able to reproduce soil moisture probability density function, obtained analytically in previous studies for different climates and soils in steady-state conditions; consequently it can be used to compute both the soil moisture time-profile and the vegetation static water stress time-profile in non-steady conditions.

    Here the differences between the steady-analytical and the non-steady numerical probability density functions are analyzed, showing how the proposed numerical model is able to capture the effects of winter recharge on the soil moisture. The dynamic

  5. The generalized model of polypeptide chain describing the helix-coil transition in biopolymers

    International Nuclear Information System (INIS)

    Mamasakhlisov, E.S.; Badasyan, A.V.; Tsarukyan, A.V.; Grigoryan, A.V.; Morozov, V.F.

    2005-07-01

    In this paper we summarize some results of our theoretical investigations of helix-coil transition both in single-strand (polypeptides) and two-strand (polynucleotides) macromolecules. The Hamiltonian of the Generalized Model of Polypeptide Chain (GMPC) is introduced to describe the system in which the conformations are correlated over some dimensional range Δ (it equals 3 for polypeptide, because one H-bond fixes three pairs of rotation, for double strand DNA it equals to one chain rigidity because of impossibility of loop formation on the scale less than Δ). The Hamiltonian does not contain any parameter designed especially for helix-coil transition and uses pure molecular microscopic parameters (the energy of hydrogen bond formation, reduced partition function of repeated unit, the number of repeated units fixed by one hydrogen bond, the energies of interaction between the repeated units and the solvent molecules). To calculate averages we evaluate the partition function using the transfer-matrix approach. The GMPC allowed to describe the influence of a number of factors, affecting the transition, basing on a unified microscopic approach. Thus we obtained, that solvents change transition temperature and interval in different ways, depending on type of solvent and on energy of solvent- macromolecule interaction; stacking on the background of H-bonding increases stability and decreases cooperativity of melting. For heterogeneous DNA we could analytically derive well known formulae for transition temperature and interval. In the framework of GMPC we calculate and show the difference of two order parameters of helix-coil transition - the helicity degree, and the average fraction of repeated units in helical conformation. Given article has the aim to review the results obtained during twenty years in the context of GMPC. (author)

  6. Applying a physical continuum model to describe the broadband X-ray spectra of accreting pulsars at high luminosity

    Science.gov (United States)

    Pottschmidt, Katja; Hemphill, Paul B.; Wolff, Michael T.; Cheatham, Diana M.; Iwakiri, Wataru; Gottlieb, Amy M.; Falkner, Sebastian; Ballhausen, Ralf; Fuerst, Felix; Kuehnel, Matthias; Ferrigno, Carlo; Becker, Peter A.; Wood, Kent S.; Wilms, Joern

    2018-01-01

    A new window for better understanding the accretion onto strongly magnetized neutron stars in X-ray binaries is opening. In these systems the accreted material follows the magnetic field lines as it approaches the neutron star, forming accretion columns above the magnetic poles. The plasma falls toward the neutron star surface at near-relativistic speeds, losing energy by emitting X-rays. The X-ray spectral continua are commonly described using phenomenological models, i.e., power laws with different types of curved cut-offs at higher energies. Here we consider high luminosity pulsars. In these systems the mass transfer rate is high enough that the accreting plasma is thought to be decelerated in a radiation-dominated radiative shock in the accretion columns. While the theory of the emission from such shocks had already been developed by 2007, a model for direct comparison with X-ray continuum spectra in xspec or isis has only recently become available. Characteristic parameters of this model are the accretion column radius and the plasma temperature, among others. Here we analyze the broadband X-ray spectra of the accreting pulsars Centaurus X-3 and 4U 1626-67 obtained with NuSTAR. We present results from traditional empirical modeling as well as successfully apply the radiation-dominated radiative shock model. We also take the opportunity to compare to similar recent analyses of both sources using these and other observations.

  7. A model for successful use of student response systems.

    Science.gov (United States)

    Klein, Kathleen; Kientz, Mary

    2013-01-01

    This article presents a model developed to assist teachers in selecting, implementing, and assessing student response system (SRS) use in the classroom. Research indicates that SRS technology is effective in achieving desired outcomes in higher education settings. Studies indicate that effective SRS use promotes greater achievement of learning outcomes, increased student attention, improved class participation, and active engagement. The model offered in this article is based on best practices described in the literature and several years of SRS use in a traditional higher education classroom setting. Student feedback indicates increased class participation and engagement with SRS technology. Teacher feedback indicates opportunities for contingent teaching. The model described in this article provides a process to assist teachers in the successful selection, implementation, and assessment of SRS technology in the classroom.

  8. Conceptual modeling of postmortem evaluation findings to describe dairy cow deaths.

    Science.gov (United States)

    McConnel, C S; Garry, F B; Hill, A E; Lombard, J E; Gould, D H

    2010-01-01

    Dairy cow mortality levels in the United States are excessive and increasing over time. To better define cause and effect and combat rising mortality, clearer definitions of the reasons that cows die need to be acquired through thorough necropsy-based postmortem evaluations. The current study focused on organizing information generated from postmortem evaluations into a monitoring system that is based on the fundamentals of conceptual modeling and that will potentially be translatable into on-farm relational databases. This observational study was conducted on 3 high-producing, commercial dairies in northern Colorado. Throughout the study period a thorough postmortem evaluation was performed by veterinarians on cows that died on each dairy. Postmortem data included necropsy findings, life-history features (e.g., birth date, lactation number, lactational and reproductive status), clinical history and treatments, and pertinent aspects of operational management that were subject to change and considered integral to the poor outcome. During this study, 174 postmortem evaluations were performed. Postmortem evaluation results were conceptually modeled to view each death within the context of the web of factors influencing the dairy and the cow. Categories were formulated describing mortality in terms of functional characteristics potentially amenable to easy performance evaluation, management oversight, and research. In total, 21 death categories with 7 category themes were created. Themes included specific disease processes with variable etiologies, failure of disease recognition or treatment, traumatic events, multifactorial failures linked to transition or negative energy balance issues, problems with feed management, miscellaneous events not amenable to prevention or treatment, and undetermined causes. Although postmortem evaluations provide the relevant information necessary for framing a cow's death, a restructuring of on-farm databases is needed to integrate this

  9. Modeling Student Success in Engineering Education

    Science.gov (United States)

    Jin, Qu

    2013-01-01

    In order for the United States to maintain its global competitiveness, the long-term success of our engineering students in specific courses, programs, and colleges is now, more than ever, an extremely high priority. Numerous studies have focused on factors that impact student success, namely academic performance, retention, and/or graduation.…

  10. Rapid-relocation model for describing high-fluence retention of rare gases implanted in solids

    Science.gov (United States)

    Wittmaack, K.

    2009-09-01

    to be due to bombardment induced relocation and reemission, only the remaining 10% (or less) can be attributed to sputter erosion. The relocation efficiency is interpreted as the 'speed' of radiation enhanced diffusion towards the surface. The directionality of diffusion is attributed to the gradient of the defect density on the large-depth side of the damage distribution where most of the implanted rare gas atoms come to rest. Based on SRIM calculations, two representative parameters are defined, the peak number of lattice displacements, Nd,m, and the spacing, △ zr,d, between the peaks of the range and the damage distributions. Support in favour of rapid rare gas relocation by radiation enhanced diffusion is provided by the finding that the relocation efficiencies for Ar and Xe, which vary by up to one order of magnitude, scale as Ψ=kN/Δz, independent to the implantation energy (10-80 keV Ar, 10-500 keV Xe), within an error margin of only ± 15%. The parameter k contains the properties of the implanted rare gas atoms. A recently described computer simulation model, which assumed that the pressure established by the implanted gas drives reemission, is shown to reproduce measured Xe profiles quite well, but only at that energy at which the fitting parameter of the model was determined (140 keV). Using the same parameter at other energies, deviations by up to a factor of four are observed.

  11. Predictions and implications of a poisson process model to describe corrosion of transuranic waste drums

    International Nuclear Information System (INIS)

    Lyon, B.F.; Holmes, J.A.; Wilbert, K.A.

    1995-01-01

    A risk assessment methodology is described in this paper to compare risks associated with immediate or near-term retrieval of transuranic (TRU) waste drums from bermed storage versus delayed retrieval. Assuming a Poisson process adequately describes corrosion, significant breaching of drums is expected to begin at - 15 and 24 yr for pitting and general corrosion, respectively. Because of this breaching, more risk will be incurred by delayed than by immediate retrieval

  12. Development and application of an asymmetric deformation model to describe the fuel rod behaviour during LOCA

    International Nuclear Information System (INIS)

    Chakraborty, A.K.; Schubert, J.D.

    1983-01-01

    For calculation of clad ballooning from single rod and rod bundle experiments a model considering the influences of azimuthal temperature gradients due to the existing eccentricity of the pellets has been developed. This model is based on the secondary creep model of Norton and on the concentric deformation model ending in cladding burst as proposed by F. Erbacher. The new model considers the azimuthal temperature differences along the cladding and the resulting differences in deformations. With this model, calculations of cladding burst deformations from single rod and rod bundle experiments are performed with good agreement

  13. Review Of Applied Mathematical Models For Describing The Behaviour Of Aqueous Humor In Eye Structures

    Science.gov (United States)

    Dzierka, M.; Jurczak, P.

    2015-12-01

    In the paper, currently used methods for modeling the flow of the aqueous humor through eye structures are presented. Then a computational model based on rheological models of Newtonian and non-Newtonian fluids is proposed. The proposed model may be used for modeling the flow of the aqueous humor through the trabecular meshwork. The trabecular meshwork is modeled as an array of rectilinear parallel capillary tubes. The flow of Newtonian and non-Newtonian fluids is considered. As a results of discussion mathematical equations of permeability of porous media and velocity of fluid flow through porous media have been received.

  14. Integrated model of insulin and glucose kinetics describing both hepatic glucose and pancreatic insulin regulation

    DEFF Research Database (Denmark)

    Erlandsen, Mogens; Martinussen, Christoffer; Gravholt, Claus Højbjerg

    2018-01-01

    AbstractBackground and objectives Modeling of glucose kinetics has to a large extent been based on models with plasma insulin as a known forcing function. Furthermore, population-based statistical methods for parameter estimation in these models have mainly addressed random inter-individual varia......AbstractBackground and objectives Modeling of glucose kinetics has to a large extent been based on models with plasma insulin as a known forcing function. Furthermore, population-based statistical methods for parameter estimation in these models have mainly addressed random inter......-individual variations and not intra-individual variations in the parameters. Here we present an integrated whole-body model of glucose and insulin kinetics which extends the well-known two-compartment glucose minimal model. The population-based estimation technique allow for quantification of both random inter......- and intra-individual variation in selected parameters using simultaneous data series on glucose and insulin. Methods We extend the two-compartment glucose model into a whole-body model for both glucose and insulin using a simple model for the pancreas compartment which includes feedback of glucose on both...

  15. Selection of heat transfer model for describing short-pulse laser heating silica-based sensor

    International Nuclear Information System (INIS)

    Hao Xiangnan; Nie Jinsong; Li Hua; Bian Jintian

    2012-01-01

    The fundamental equations of Fourier heat transfer model and non-Fourier heat transfer model were numerically solved, with the finite difference method. The relative changes between temperature curves of the two heat transfer models were analyzed under laser irradiation with different pulse widths of 10 ns, 1 ns, 100 ps, 10 ps. The impact of different thermal relaxation time on non-Fourier model results was discussed. For pulses of pulse width less than or equal to 100 ps irradiating silicon material, the surface temperature increases slowly and carrier effect happens, which the non-Fourier model can reflect properly. As for general material, when the pulse width is less than or equal to the thermal relaxation time of material, carrier effect occurs. In this case, the non-Fourier model should be used. (authors)

  16. Non-linear modelling to describe lactation curve in Gir crossbred cows

    Directory of Open Access Journals (Sweden)

    Yogesh C. Bangar

    2017-02-01

    Full Text Available Abstract Background The modelling of lactation curve provides guidelines in formulating farm managerial practices in dairy cows. The aim of the present study was to determine the suitable non-linear model which most accurately fitted to lactation curves of five lactations in 134 Gir crossbred cows reared in Research-Cum-Development Project (RCDP on Cattle farm, MPKV (Maharashtra. Four models viz. gamma-type function, quadratic model, mixed log function and Wilmink model were fitted to each lactation separately and then compared on the basis of goodness of fit measures viz. adjusted R2, root mean square error (RMSE, Akaike’s Informaion Criteria (AIC and Bayesian Information Criteria (BIC. Results In general, highest milk yield was observed in fourth lactation whereas it was lowest in first lactation. Among the models investigated, mixed log function and gamma-type function provided best fit of the lactation curve of first and remaining lactations, respectively. Quadratic model gave least fit to lactation curve in almost all lactations. Peak yield was observed as highest and lowest in fourth and first lactation, respectively. Further, first lactation showed highest persistency but relatively higher time to achieve peak yield than other lactations. Conclusion Lactation curve modelling using gamma-type function may be helpful to setting the management strategies at farm level, however, modelling must be optimized regularly before implementing them to enhance productivity in Gir crossbred cows.

  17. Fractional single-phase-lagging heat conduction model for describing anomalous diffusion

    Directory of Open Access Journals (Sweden)

    T.N. Mishra

    2016-03-01

    Full Text Available The fractional single-phase-lagging (FSPL heat conduction model is obtained by combining scalar time fractional conservation equation to the single-phase-lagging (SPL heat conduction model. Based on the FSPL heat conduction model, anomalous diffusion within a finite thin film is investigated. The effect of different parameters on solution has been observed and studied the asymptotic behavior of the FSPL model. The analytical solution is obtained using Laplace transform method. The whole analysis is presented in dimensionless form. Numerical examples of particular interest have been studied and discussed in details.

  18. Using a Model to Describe Students' Inductive Reasoning in Problem Solving

    Science.gov (United States)

    Canadas, Maria C.; Castro, Encarnacion; Castro, Enrique

    2009-01-01

    Introduction: We present some aspects of a wider investigation (Canadas, 2007), whose main objective is to describe and characterize inductive reasoning used by Spanish students in years 9 and 10 when they work on problems that involved linear and quadratic sequences. Method: We produced a test composed of six problems with different…

  19. EMPIRICAL MODELS FOR DESCRIBING FIRE BEHAVIOR IN BRAZILIAN COMMERCIAL EUCALYPT PLANTATIONS

    Directory of Open Access Journals (Sweden)

    Benjamin Leonardo Alves White

    2016-12-01

    Full Text Available Modeling forest fire behavior is an important task that can be used to assist in fire prevention and suppression operations. However, according to previous studies, the existing common worldwide fire behavior models used do not correctly estimate the fire behavior in Brazilian commercial hybrid eucalypt plantations. Therefore, this study aims to build new empirical models to predict the fire rate of spread, flame length and fuel consumption for such vegetation. To meet these objectives, 105 laboratory experimental burns were done, where the main fuel characteristics and weather variables that influence fire behavior were controlled and/or measured in each experiment. Dependent and independent variables were fitted through multiple regression analysis. The fire rate of spread proposed model is based on the wind speed, fuel bed bulk density and 1-h dead fuel moisture content (r2 = 0.86; the flame length model is based on the fuel bed depth, 1-h dead fuel moisture content and wind speed (r2 = 0.72; the fuel consumption proposed model has the 1-h dead fuel moisture, fuel bed bulk density and 1-h dead dry fuel load as independent variables (r2= 0.80. These models were used to develop a new fire behavior software, the “Eucalyptus Fire Safety System”.

  20. A simple geometrical model describing shapes of soap films suspended on two rings

    Science.gov (United States)

    Herrmann, Felix J.; Kilvington, Charles D.; Wildenberg, Rebekah L.; Camacho, Franco E.; Walecki, Wojciech J.; Walecki, Peter S.; Walecki, Eve S.

    2016-09-01

    We measured and analysed the stability of two types of soap films suspended on two rings using the simple conical frusta-based model, where we use common definition of conical frustum as a portion of a cone that lies between two parallel planes cutting it. Using frusta-based we reproduced very well-known results for catenoid surfaces with and without a central disk. We present for the first time a simple conical frusta based spreadsheet model of the soap surface. This very simple, elementary, geometrical model produces results surprisingly well matching the experimental data and known exact analytical solutions. The experiment and the spreadsheet model can be used as a powerful teaching tool for pre-calculus and geometry students.

  1. How well do basic models describe the turbidity currents coming down Monterey and Congo Canyon?

    Science.gov (United States)

    Cartigny, M.; Simmons, S.; Heerema, C.; Xu, J. P.; Azpiroz, M.; Clare, M. A.; Cooper, C.; Gales, J. A.; Maier, K. L.; Parsons, D. R.; Paull, C. K.; Sumner, E. J.; Talling, P.

    2017-12-01

    Turbidity currents rival rivers in their global capacity to transport sediment and organic carbon. Furthermore, turbidity currents break submarine cables that now transport >95% of our global data traffic. Accurate turbidity current models are thus needed to quantify their transport capacity and to predict the forces exerted on seafloor structures. Despite this need, existing numerical models are typically only calibrated with scaled-down laboratory measurements due to the paucity of direct measurements of field-scale turbidity currents. This lack of calibration thus leaves much uncertainty in the validity of existing models. Here we use the most detailed observations of turbidity currents yet acquired to validate one of the most fundamental models proposed for turbidity currents, the modified Chézy model. Direct measurements on which the validation is based come from two sites that feature distinctly different flow modes and grain sizes. The first are from the multi-institution Coordinated Canyon Experiment (CCE) in Monterey Canyon, California. An array of six moorings along the canyon axis captured at least 15 flow events that lasted up to hours. The second is the deep-sea Congo Canyon, where 10 finer grained flows were measured by a single mooring, each lasting several days. Moorings captured depth-resolved velocity and suspended sediment concentration at high resolution (turbidity currents; the modified Chézy model. This basic model has been very useful for river studies over the past 200 years, as it provides a rapid estimate of how flow velocity varies with changes in river level and energy slope. Chézy-type models assume that the gravitational force of the flow equals the friction of the river-bed. Modified Chézy models have been proposed for turbidity currents. However, the absence of detailed measurements of friction and sediment concentration within full-scale turbidity currents has forced modellers to make rough assumptions for these parameters. Here

  2. Transport in semiconductor nanowire superlattices described by coupled quantum mechanical and kinetic models.

    Science.gov (United States)

    Alvaro, M; Bonilla, L L; Carretero, M; Melnik, R V N; Prabhakar, S

    2013-08-21

    In this paper we develop a kinetic model for the analysis of semiconductor superlattices, accounting for quantum effects. The model consists of a Boltzmann-Poisson type system of equations with simplified Bhatnagar-Gross-Krook collisions, obtained from the general time-dependent Schrödinger-Poisson model using Wigner functions. This system for superlattice transport is supplemented by the quantum mechanical part of the model based on the Ben-Daniel-Duke form of the Schrödinger equation for a cylindrical superlattice of finite radius. The resulting energy spectrum is used to characterize the Fermi-Dirac distribution that appears in the Bhatnagar-Gross-Krook collision, thereby coupling the quantum mechanical and kinetic parts of the model. The kinetic model uses the dispersion relation obtained by the generalized Kronig-Penney method, and allows us to estimate radii of quantum wire superlattices that have the same miniband widths as in experiments. It also allows us to determine more accurately the time-dependent characteristics of superlattices, in particular their current density. Results, for several experimentally grown superlattices, are discussed in the context of self-sustained coherent oscillations of the current density which are important in an increasing range of current and potential applications.

  3. Using logic model methods in systematic review synthesis: describing complex pathways in referral management interventions.

    Science.gov (United States)

    Baxter, Susan K; Blank, Lindsay; Woods, Helen Buckley; Payne, Nick; Rimmer, Melanie; Goyder, Elizabeth

    2014-05-10

    There is increasing interest in innovative methods to carry out systematic reviews of complex interventions. Theory-based approaches, such as logic models, have been suggested as a means of providing additional insights beyond that obtained via conventional review methods. This paper reports the use of an innovative method which combines systematic review processes with logic model techniques to synthesise a broad range of literature. The potential value of the model produced was explored with stakeholders. The review identified 295 papers that met the inclusion criteria. The papers consisted of 141 intervention studies and 154 non-intervention quantitative and qualitative articles. A logic model was systematically built from these studies. The model outlines interventions, short term outcomes, moderating and mediating factors and long term demand management outcomes and impacts. Interventions were grouped into typologies of practitioner education, process change, system change, and patient intervention. Short-term outcomes identified that may result from these interventions were changed physician or patient knowledge, beliefs or attitudes and also interventions related to changed doctor-patient interaction. A range of factors which may influence whether these outcomes lead to long term change were detailed. Demand management outcomes and intended impacts included content of referral, rate of referral, and doctor or patient satisfaction. The logic model details evidence and assumptions underpinning the complex pathway from interventions to demand management impact. The method offers a useful addition to systematic review methodologies. PROSPERO registration number: CRD42013004037.

  4. FORMATIVE ASSESSMENT MODEL OF LEARNING SUCCESS ACHIEVEMENTS

    Directory of Open Access Journals (Sweden)

    Mikhailova Elena Konstantinovna

    2013-05-01

    Full Text Available The paper is devoted to the problem of assessment of the school students’ learning success achievements. The problem is investigated from the viewpoint of assessing the students’ learning outcomes that is aimed to ensure the teachers and students with the means and conditions to improve the educational process and results.

  5. An empirical model to describe performance degradation for warranty abuse detection in portable electronics

    International Nuclear Information System (INIS)

    Oh, Hyunseok; Choi, Seunghyuk; Kim, Keunsu; Youn, Byeng D.; Pecht, Michael

    2015-01-01

    Portable electronics makers have introduced liquid damage indicators (LDIs) into their products to detect warranty abuse caused by water damage. However, under certain conditions, these indicators can exhibit inconsistencies in detecting liquid damage. This study is motivated by the fact that the reliability of LDIs in portable electronics is suspected. In this paper, first, the scheme of life tests is devised for LDIs in conjunction with a robust color classification rule. Second, a degradation model is proposed by considering the two physical mechanisms—(1) phase change from vapor to water and (2) water transport in the porous paper—for LDIs. Finally, the degradation model is validated with additional tests using actual smartphone sets subjected to the thermal cycling of −15 °C to 25 °C and the relative humidity of 95%. By employing the innovative life testing scheme and the novel performance degradation model, it is expected that the performance of LDIs for a particular application can be assessed quickly and accurately. - Highlights: • Devise an efficient scheme of life testing for a warranty abuse detector in portable electronics. • Develop a performance degradation model for the warranty abuse detector used in portable electronics. • Validate the performance degradation model with life tests of actual smartphone sets. • Help make a decision on warranty service in portable electronics manufacturers

  6. A model, describing the influence of water management alternatives on dike stability

    Directory of Open Access Journals (Sweden)

    J. W. M. Lambert

    2015-11-01

    Full Text Available The awareness is rising that economic effects of Land Subsidence are high. Nevertheless, quantifying these economic losses is difficult and, as far as known, not yet done in a sophisticated way. Also, to be able to decide about future strategies, for example to avoid or decrease subsidence, it is necessary to know the financial consequences of measures and possible solutions. As a first step to quantify these economic effects, a MODFLOW-SCR (coupled MODFLOW-Settlements model is coupled with the model DAM. Based on the local stratigraphy, the shape and composition of the existing dike or levee, the level of the surface water and the surface level, macro-stability of the dike is calculated and – if the dike does not meet the required stability – adaptions are proposed. The model enables to separate effects that are caused by sea-level rise and the effects of subsidence. Coupling the DAM model with an economic model to calculate costs of these adaptions is under construction.

  7. Integrated compartmental model for describing the transport of solute in a fractured porous medium. [FRACPORT

    Energy Technology Data Exchange (ETDEWEB)

    DeAngelis, D.L.; Yeh, G.T.; Huff, D.D.

    1984-10-01

    This report documents a model, FRACPORT, that simulates the transport of a solute through a fractured porous matrix. The model should be useful in analyzing the possible transport of radionuclides from shallow-land burial sites in humid environments. The use of the model is restricted to transport through saturated zones. The report first discusses the general modeling approach used, which is based on the Integrated Compartmental Method. The basic equations of solute transport are then presented. The model, which assumes a known water velocity field, solves these equations on two different time scales; one related to rapid transport of solute along fractures and the other related to slower transport through the porous matrix. FRACPORT is validated by application to a simple example of fractured porous medium transport that has previously been analyzed by other methods. Then its utility is demonstrated in analyzing more complex cases of pulses of solute into a fractured matrix. The report serves as a user's guide to FRACPORT. A detailed description of data input, along with a listing of input for a sample problem, is provided. 16 references, 18 figures, 3 tables.

  8. Modified VMD model with correct analytic properties for describing electromagnetic structure of He4 nucleus

    International Nuclear Information System (INIS)

    Dubnicka, S.; Lucan, L.

    1988-12-01

    A new phenomenological model for electromagnetic (e.m.) form factor (ff) of He 4 nucleus is presented, which is based on a modification of the well proved in e.m. interactions of hadrons vector-meson-dominance (VMD) model by means of an incorporation of correct He 4 ff analytic properties, nonzero vector-meson widths and the right power asymptotic behaviour predicted by the quark model. It reproduces the existing experimental information on He 4 e.m. ff in the space-like region quite well. Furthermore, couplings of all well established isoscalar vector mesons with J pc = 1 -- to He 4 nucleus are evaluated as a result of the analysis and the time-like region behaviour of He 4 e.m. ff is predicted. As a consequence of the latter the total cross section of e + e - → He 4 He-bar 4 process is calculated for the first time. (author). 17 refs, 3 figs

  9. Comparison of two mathematical models for describing heat-induced cell killing

    International Nuclear Information System (INIS)

    Roti Roti, J.L.; Henle, K.J.

    1980-01-01

    A computer-based minimization algorithm is utilized to obtain the optimum fits of two models to hyperthermic cell killing data. The models chosen are the multitarget, single-hit equation, which is in general use, and the linear-quadratic equation, which has been applied to cell killing by ionizing irradiation but not to heat-induced cell killing. The linear-quadratic equation fits hyperthermic cell killing data as well as the multitarget, single-hit equation. Both parameters of the linear-quadratic equation obey the Arrhenius law, whereas only one of the two parameters of the multitarget, single-hit equation obeys the Arrhenius law. Thus the linear-quadratic function can completely define cell killing as a function of both time and temperature. In addition, the linear-quadratic model will provide a simplified approach to the study of the synergism between heat and X irradiation

  10. Benchmarking of numerical models describing the dispersion of radionuclides in the Arctic Seas

    DEFF Research Database (Denmark)

    Scott, E.M.; Gurbutt, P.; Harms, I.

    1997-01-01

    As part of the International Arctic Seas Assessment Project (IASAP) of the International Atomic Energy Agency (IAEA), a working group was created to model the dispersal and transfer of radionuclides released from radioactive waste disposed of in the Kara Sea. The objectives of this group are: (1......) development of realistic and reliable assessment models for the dispersal of radioactive contaminants both within, and from, the Arctic ocean; and (2) evaluation of the contributions of different transfer mechanisms to contaminant dispersal and hence, ultimately, to the risks to human health and environment...

  11. A gauge model describing N relativistic particles bound by linear forces

    International Nuclear Information System (INIS)

    Filippov, A.T.

    1988-01-01

    A relativistic model of N particles bound by linear forces is obtained by applying the gauging procedure to the linear canonical symmteries of a simple (rudimentary) nonrelativistic N-particle Lagrangian extended to relativistic phase space. The new (gauged) Lagrangian is formally Poincare invariant, the Hamiltonian is a linear combination of first-class constraints which are closed with respect to Pisson brackets and generate the localized canonical symmteries. The gauge potentials appear as the Lagrange multipliers of the constraints. Gauge fixing and quantization of the model are also briefly discussed. 11 refs

  12. Feasibility study for a plasticity model to describe the transient thermomechanical behavior of Zircaloy. Final report

    International Nuclear Information System (INIS)

    Valanis, K.C.

    1979-11-01

    The conceptual framework of the endochronic theory is described and a summary of its capabilities, as well as past and potential applications to the mechanical response of metals to general histories of deformation, temperature, and radiation is given. The purely mechanical part of the theory is developed on the basis of the concept of intrinsic time which serves to incorporate in a unified and concise fashion the effects of strain history and strain rate on the stress response. The effects of temperature are introduced by means of the theory of deformation kinetics through its relation to the internal variable theory of irreversible thermodynamics. As a result, physically sound formulae are developed which account for the effect of temperature history on the stress response. An approach to describing irradiation effects is briefly discussed. More research would be needed to define appropriate constitutive representations for Zircaloy. The endochronic theory is also looked at from a numerical analysis viewpoint of future applications to problems of practical interest. In appendix B a first cut attempt has been made to assess the computational efficiencies of material constitutive equation approaches

  13. q-deformed Einstein's model to describe specific heat of solid

    Science.gov (United States)

    Guha, Atanu; Das, Prasanta Kumar

    2018-04-01

    Realistic phenomena can be described more appropriately using generalized canonical ensemble, with proper parameter sets involved. We have generalized the Einstein's theory for specific heat of solid in Tsallis statistics, where the temperature fluctuation is introduced into the theory via the fluctuation parameter q. At low temperature the Einstein's curve of the specific heat in the nonextensive Tsallis scenario exactly lies on the experimental data points. Consequently this q-modified Einstein's curve is found to be overlapping with the one predicted by Debye. Considering only the temperature fluctuation effect(even without considering more than one mode of vibration is being triggered) we found that the CV vs T curve is as good as obtained by considering the different modes of vibration as suggested by Debye. Generalizing the Einstein's theory in Tsallis statistics we found that a unique value of the Einstein temperature θE along with a temperature dependent deformation parameter q(T) , can well describe the phenomena of specific heat of solid i.e. the theory is equivalent to Debye's theory with a temperature dependent θD.

  14. Using Rouse-Fowler model to describe radiation-induced electrical conductivity of nanocomposite materials

    Science.gov (United States)

    Dyuryagina, N. S.; Yalovets, A. P.

    2017-05-01

    Using the Rouse-Fowler (RF) model this work studies the radiation-induced electrical conductivity of a polymer nanocomposite material with spherical nanoparticles against the intensity and exposure time of gamma-ray, concentration and size of nanoparticles. The research has found the energy distribution of localized statesinduced by nanoparticles. The studies were conducted on polymethylmethacrylate (PMMA) with CdS nanoparticles.

  15. Kinetic model describing the UV/H2O2 photodegradation of phenol from water

    Directory of Open Access Journals (Sweden)

    Rubio-Clemente Ainhoa

    2017-01-01

    Full Text Available A kinetic model for phenol transformation through the UV/H2O2 system was developed and validated. The model includes the pollutant decomposition by direct photolysis and HO•, HO2• and O2 •- oxidation. HO• scavenging effects of CO3 2-, HCO3 -, SO4 2- and Cl- were also considered, as well as the pH changes as the process proceeds. Additionally, the detrimental action of the organic matter and reaction intermediates in shielding UV and quenching HO• was incorporated. It was observed that the model can accurately predict phenol abatement using different H2O2/phenol mass ratios (495, 228 and 125, obtaining an optimal H2O2/phenol ratio of 125, leading to a phenol removal higher than 95% after 40 min of treatment, where the main oxidation species was HO•. The developed model could be relevant for calculating the optimal level of H2O2 efficiently degrading the pollutant of interest, allowing saving in costs and time.

  16. CAN A NANOFLARE MODEL OF EXTREME-ULTRAVIOLET IRRADIANCES DESCRIBE THE HEATING OF THE SOLAR CORONA?

    Energy Technology Data Exchange (ETDEWEB)

    Tajfirouze, E.; Safari, H. [Department of Physics, University of Zanjan, P.O. Box 45195-313, Zanjan (Iran, Islamic Republic of)

    2012-01-10

    Nanoflares, the basic units of impulsive energy release, may produce much of the solar background emission. Extrapolation of the energy frequency distribution of observed microflares, which follows a power law to lower energies, can give an estimation of the importance of nanoflares for heating the solar corona. If the power-law index is greater than 2, then the nanoflare contribution is dominant. We model a time series of extreme-ultraviolet emission radiance as random flares with a power-law exponent of the flare event distribution. The model is based on three key parameters: the flare rate, the flare duration, and the power-law exponent of the flare intensity frequency distribution. We use this model to simulate emission line radiance detected in 171 A, observed by Solar Terrestrial Relation Observatory/Extreme-Ultraviolet Imager and Solar Dynamics Observatory/Atmospheric Imaging Assembly. The observed light curves are matched with simulated light curves using an Artificial Neural Network, and the parameter values are determined across the active region, quiet Sun, and coronal hole. The damping rate of nanoflares is compared with the radiative losses cooling time. The effect of background emission, data cadence, and network sensitivity on the key parameters of the model is studied. Most of the observed light curves have a power-law exponent, {alpha}, greater than the critical value 2. At these sites, nanoflare heating could be significant.

  17. Exponential law as a more compatible model to describe orbits of planetary systems

    Directory of Open Access Journals (Sweden)

    M Saeedi

    2012-12-01

    Full Text Available   According to the Titus-Bode law, orbits of planets in the solar system obey a geometric progression. Many investigations have been launched to improve this law. In this paper, we apply square and exponential models to planets of solar system, moons of planets, and some extra solar systems, and compare them with each other.

  18. Predictive model to describe water migration in cellular solid foods during storage

    NARCIS (Netherlands)

    Voogt, J.A.; Hirte, A.; Meinders, M.B.J.

    2011-01-01

    BACKGROUND: Water migration in cellular solid foods during storage causes loss of crispness. To improve crispness retention, physical understanding of this process is needed. Mathematical models are suitable tools to gain this physical knowledge. RESULTS: Water migration in cellular solid foods

  19. Predictive model to describe water migration in cellular solid foods during storage

    NARCIS (Netherlands)

    Voogt, J.A.; Hirte, A.; Meinders, M.B.J.

    2011-01-01

    Background: Water migration in cellular solid foods during storage causes loss of crispness. To improve crispness retention, physical understanding of this process is needed. Mathematical models are suitable tools to gain this physical knowledge. Results: Water migration in cellular solid foods

  20. A vapour bubble collapse model to describe the fragmentation of low-melting materials

    International Nuclear Information System (INIS)

    Benz, R.; Schober, P.

    1977-11-01

    By means of a model, the fragmentation of a hot melt of metal in consequence of collapsing vapour-bubbles is investigated. In particular the paper deals with the development of the physical model-ideas for calculation of the temperature of contact that adjusts between the temperature of the melt and the coolant, of the waiting-time until bubble-nucleation occurs and of the maximal obtainable vapour-bubble-radius in dependence of the coolant-temperature. After that follows the description of the computing-program belonging to this model and of the results of an extensive parameter-study. The study examined the influence of the temperature of melt and coolant, the melted mass, the nucleation-site-density, the average maximum bubble-radius, the duration of film-breakdown and the coefficient of heat-transition. The calculation of the process of fragmentation turns out to be according to expectation, whereas the duration of this process seems to be somewhat too long. The dependence of the surface-enlargement on the subcooling of the water-bath and the initial temperature of the melt is not yet reproduced satisfactorily by the model. The reasons for this are the temperature-increase of the water-bath as well as the fact that the coupling of heat-flux-density and nucleation-site-density are not taken into consideration. Further improvement of the model is necessary and may improve the results in the sense of the experimental observations. (orig.) [de

  1. Atomic-orbital expansion model for describing ion-atom collisions at intermediate and low energies

    International Nuclear Information System (INIS)

    Lin, C.D.; Fritsch, W.

    1983-01-01

    In the description of inelastic processes in ion-atom collisions at moderate energies, the semiclassical close-coupling method is well established as the standard method. Ever since the pioneering work on H + + H in the early 60's, the standard procedure is to expand the electronic wavefunction in terms of molecular orbitals (MO) or atomic orbitals (AO) for describing collisions at, respectively, low or intermediate velocities. It has been recognized since early days that traveling orbitals are needed in the expansions in order to represent the asymptotic states in the collisions correctly. While the adoption of such traveling orbitals presents no conceptual difficulties for expansions using atomic orbitals, the situation for molecular orbitals is less clear. In recent years, various forms of traveling MO's have been proposed, but conflicting results for several well-studied systems have been reported

  2. Methodology for Designing Models Predicting Success of Infertility Treatment

    OpenAIRE

    Alireza Zarinara; Mohammad Mahdi Akhondi; Hojjat Zeraati; Koorsh Kamali; Kazem Mohammad

    2016-01-01

    Abstract Background: The prediction models for infertility treatment success have presented since 25 years ago. There are scientific principles for designing and applying the prediction models that is also used to predict the success rate of infertility treatment. The purpose of this study is to provide basic principles for designing the model to predic infertility treatment success. Materials and Methods: In this paper, the principles for developing predictive models are explained and...

  3. A physical model describing the interaction of nuclear transport receptors with FG nucleoporin domain assemblies.

    Science.gov (United States)

    Zahn, Raphael; Osmanović, Dino; Ehret, Severin; Araya Callis, Carolina; Frey, Steffen; Stewart, Murray; You, Changjiang; Görlich, Dirk; Hoogenboom, Bart W; Richter, Ralf P

    2016-04-08

    The permeability barrier of nuclear pore complexes (NPCs) controls bulk nucleocytoplasmic exchange. It consists of nucleoporin domains rich in phenylalanine-glycine motifs (FG domains). As a bottom-up nanoscale model for the permeability barrier, we have used planar films produced with three different end-grafted FG domains, and quantitatively analyzed the binding of two different nuclear transport receptors (NTRs), NTF2 and Importin β, together with the concomitant film thickness changes. NTR binding caused only moderate changes in film thickness; the binding isotherms showed negative cooperativity and could all be mapped onto a single master curve. This universal NTR binding behavior - a key element for the transport selectivity of the NPC - was quantitatively reproduced by a physical model that treats FG domains as regular, flexible polymers, and NTRs as spherical colloids with a homogeneous surface, ignoring the detailed arrangement of interaction sites along FG domains and on the NTR surface.

  4. A stochastic Markov chain model to describe lung cancer growth and metastasis.

    Directory of Open Access Journals (Sweden)

    Paul K Newton

    Full Text Available A stochastic Markov chain model for metastatic progression is developed for primary lung cancer based on a network construction of metastatic sites with dynamics modeled as an ensemble of random walkers on the network. We calculate a transition matrix, with entries (transition probabilities interpreted as random variables, and use it to construct a circular bi-directional network of primary and metastatic locations based on postmortem tissue analysis of 3827 autopsies on untreated patients documenting all primary tumor locations and metastatic sites from this population. The resulting 50 potential metastatic sites are connected by directed edges with distributed weightings, where the site connections and weightings are obtained by calculating the entries of an ensemble of transition matrices so that the steady-state distribution obtained from the long-time limit of the Markov chain dynamical system corresponds to the ensemble metastatic distribution obtained from the autopsy data set. We condition our search for a transition matrix on an initial distribution of metastatic tumors obtained from the data set. Through an iterative numerical search procedure, we adjust the entries of a sequence of approximations until a transition matrix with the correct steady-state is found (up to a numerical threshold. Since this constrained linear optimization problem is underdetermined, we characterize the statistical variance of the ensemble of transition matrices calculated using the means and variances of their singular value distributions as a diagnostic tool. We interpret the ensemble averaged transition probabilities as (approximately normally distributed random variables. The model allows us to simulate and quantify disease progression pathways and timescales of progression from the lung position to other sites and we highlight several key findings based on the model.

  5. Formulation and integration of constitutive models describing large deformations in thermoplasticity and thermoviscoplasticity

    International Nuclear Information System (INIS)

    Jansohn, W.

    1997-10-01

    This report deals with the formulation and numerical integration of constitutive models in the framework of finite deformation thermomechanics. Based on the concept of dual variables, plasticity and viscoplasticity models exhibiting nonlinear kinematic hardening as well as nonlinear isotropic hardening rules are presented. Care is taken that the evolution equations governing the hardening response fulfill the intrinsic dissipation inequality in every admissible process. In view of the development of an efficient numerical integration procedure, simplified versions of these constitutive models are supposed. In these versions, the thermoelastic strains are assumed to be small and a simplified kinematic hardening rule is considered. Additionally, in view of an implementation into the ABAQUS finite element code, the elasticity law is approximated by a hypoelasticity law. For the simplified onstitutive models, an implicit time-integration algorithm is developed. First, in order to obtain a numerical objective integration scheme, use is made of the HUGHES-WINGET-Algorithm. In the resulting system of ordinary differential equations, it can be distinguished between three differential operators representing different physical effects. The structure of this system of differential equations allows to apply an operator split scheme, which leads to an efficient integration scheme for the constitutive equations. By linearizing the integration algorithm the consistent tangent modulus is derived. In this way, the quadratic convergence of Newton's method used to solve the basic finite element equations (i.e. the finite element discretization of the governing thermomechanical field equations) is preserved. The resulting integration scheme is implemented as a user subroutine UMAT in ABAQUS. The properties of the applied algorithm are first examined by test calculations on a single element under tension-compression-loading. For demonstrating the capabilities of the constitutive theory

  6. A stochastic Markov chain model to describe lung cancer growth and metastasis.

    Science.gov (United States)

    Newton, Paul K; Mason, Jeremy; Bethel, Kelly; Bazhenova, Lyudmila A; Nieva, Jorge; Kuhn, Peter

    2012-01-01

    A stochastic Markov chain model for metastatic progression is developed for primary lung cancer based on a network construction of metastatic sites with dynamics modeled as an ensemble of random walkers on the network. We calculate a transition matrix, with entries (transition probabilities) interpreted as random variables, and use it to construct a circular bi-directional network of primary and metastatic locations based on postmortem tissue analysis of 3827 autopsies on untreated patients documenting all primary tumor locations and metastatic sites from this population. The resulting 50 potential metastatic sites are connected by directed edges with distributed weightings, where the site connections and weightings are obtained by calculating the entries of an ensemble of transition matrices so that the steady-state distribution obtained from the long-time limit of the Markov chain dynamical system corresponds to the ensemble metastatic distribution obtained from the autopsy data set. We condition our search for a transition matrix on an initial distribution of metastatic tumors obtained from the data set. Through an iterative numerical search procedure, we adjust the entries of a sequence of approximations until a transition matrix with the correct steady-state is found (up to a numerical threshold). Since this constrained linear optimization problem is underdetermined, we characterize the statistical variance of the ensemble of transition matrices calculated using the means and variances of their singular value distributions as a diagnostic tool. We interpret the ensemble averaged transition probabilities as (approximately) normally distributed random variables. The model allows us to simulate and quantify disease progression pathways and timescales of progression from the lung position to other sites and we highlight several key findings based on the model.

  7. Phenomenological Model Describing the Formation of Peeling Defects on Hot-Rolled Duplex Stainless Steel 2205

    Science.gov (United States)

    Yong-jun, Zhang; Hui, Zhang; Jing-tao, Han

    2017-05-01

    The chemical composition, morphology, and microstructure of peeling defects formed on the surface of sheets from steel 2205 under hot rolling are studied. The microstructure of the surface is analyzed using scanning electron and light microscopy. The zones affected are shown to contain nonmetallic inclusions of types Al2O3 and CaO - SiO2 - Al2O3 - MgO in the form of streak precipitates and to have an unfavorable content of austenite, which causes decrease in the ductility of the area. The results obtained are used to derive a five-stage phenomenological model of formation of such defects.

  8. Application of a non-equilibrium reaction model for describing horizontal well performance in foamy oil

    Energy Technology Data Exchange (ETDEWEB)

    Luigi, A.; Saputelli, B.; Carlas, M.; Canache, P.; Lopez, E. [DPVS Exploracion y Produccion (Venezuela)

    1998-12-31

    This study was designed to determine the activation energy ranges and frequency factor ranges in chemical reactions in heavy oils of the Orinoco Belt in Venezuela, in order to account for the kinetics of physical changes that occur in the morphology of gas-oil dispersion. A non-equilibrium reaction model was used to model foamy oil behaviour observed at SDZ-182 horizontal well in the Zuata field. Results showed that activation energy for the first reaction ranged from 0 to 0.01 BTU/lb-mol and frequency factor from 0.001 to 1000 l/day. For the second reaction the activation energy was 50x10{sub 3} BTU/lb-mol and the frequency factor 2.75x10{sub 1}2 l/day. The second reaction was highly sensitive to the modifications in activation energy and frequency factor. However, both the activation energy and frequency factor were independent of variations for the first reaction. In the case of the activation energy, the results showed that the high sensitivity of this parameter reflected the impact that temperature has on the representation of foamy oil behaviour. 8 refs., 2 tabs., 6 figs.

  9. SPATIAL MODELLING FOR DESCRIBING SPATIAL VARIABILITY OF SOIL PHYSICAL PROPERTIES IN EASTERN CROATIA

    Directory of Open Access Journals (Sweden)

    Igor Bogunović

    2016-06-01

    Full Text Available The objectives of this study were to characterize the field-scale spatial variability and test several interpolation methods to identify the best spatial predictor of penetration resistance (PR, bulk density (BD and gravimetric water content (GWC in the silty loam soil in Eastern Croatia. The measurements were made on a 25 x 25-m grid which created 40 individual grid cells. Soil properties were measured at the center of the grid cell deep 0-10 cm and 10-20 cm. Results demonstrated that PR and GWC displayed strong spatial dependence at 0-10 cm BD, while there was moderate and weak spatial dependence of PR, BD and GWC at depth of 10-20 cm. Semi-variogram analysis suggests that future sampling intervals for investigated parameters can be increased to 35 m in order to reduce research costs. Additionally, interpolation models recorded similar root mean square values with high predictive accuracy. Results suggest that investigated properties do not have uniform interpolation method implying the need for spatial modelling in the evaluation of these soil properties in Eastern Croatia.

  10. Describing model of empowering managers by applying structural equation modeling: A case study of universities in Ardabil

    Directory of Open Access Journals (Sweden)

    Maryam Ghahremani Germi

    2015-06-01

    Full Text Available Empowerment is still on the agenda as a management concept and has become a widely used management term in the last decade or so. The purpose of this research was describing model of empowering managers by applying structural equation modeling (SEM at Ardabil universities. Two hundred and twenty managers of Ardabil universities including chancellors, managers, and vice presidents of education, research, and studies participated in this study. Clear and challenging goals, evaluation of function, access to resources, and rewarding were investigated. The results indicated that the designed SEM for empowering managers at university reflects a good fitness level. As it stands out, the conceptual model in the society under investigation was used appropriately. Among variables, access to resources with 88 per cent of load factor was known as the affective variable. Evaluation of function containing 51 per cent of load factor was recognized to have less effect. Results of average rating show that evaluation of function and access to resources with 2.62 coefficients stand at first level. Due to this, they had great impact on managers' empowerment. The results of the analysis provided compelling evidence that model of empowering managers was desirable at Ardabil universities.

  11. Describing the Process of Adopting Nutrition and Fitness Apps: Behavior Stage Model Approach.

    Science.gov (United States)

    König, Laura M; Sproesser, Gudrun; Schupp, Harald T; Renner, Britta

    2018-03-13

    Although mobile technologies such as smartphone apps are promising means for motivating people to adopt a healthier lifestyle (mHealth apps), previous studies have shown low adoption and continued use rates. Developing the means to address this issue requires further understanding of mHealth app nonusers and adoption processes. This study utilized a stage model approach based on the Precaution Adoption Process Model (PAPM), which proposes that people pass through qualitatively different motivational stages when adopting a behavior. To establish a better understanding of between-stage transitions during app adoption, this study aimed to investigate the adoption process of nutrition and fitness app usage, and the sociodemographic and behavioral characteristics and decision-making style preferences of people at different adoption stages. Participants (N=1236) were recruited onsite within the cohort study Konstanz Life Study. Use of mobile devices and nutrition and fitness apps, 5 behavior adoption stages of using nutrition and fitness apps, preference for intuition and deliberation in eating decision-making (E-PID), healthy eating style, sociodemographic variables, and body mass index (BMI) were assessed. Analysis of the 5 behavior adoption stages showed that stage 1 ("unengaged") was the most prevalent motivational stage for both nutrition and fitness app use, with half of the participants stating that they had never thought about using a nutrition app (52.41%, 533/1017), whereas less than one-third stated they had never thought about using a fitness app (29.25%, 301/1029). "Unengaged" nonusers (stage 1) showed a higher preference for an intuitive decision-making style when making eating decisions, whereas those who were already "acting" (stage 4) showed a greater preference for a deliberative decision-making style (F 4,1012 =21.83, Pdigital interventions. This study highlights that new user groups might be better reached by apps designed to address a more intuitive

  12. A nonlinear beam model to describe the postbuckling of wide neo-Hookean beams

    Science.gov (United States)

    Lubbers, Luuk A.; van Hecke, Martin; Coulais, Corentin

    2017-09-01

    Wide beams can exhibit subcritical buckling, i.e. the slope of the force-displacement curve can become negative in the postbuckling regime. In this paper, we capture this intriguing behaviour by constructing a 1D nonlinear beam model, where the central ingredient is the nonlinearity in the stress-strain relation of the beams constitutive material. First, we present experimental and numerical evidence of a transition to subcritical buckling for wide neo-Hookean hyperelastic beams, when their width-to-length ratio exceeds a critical value of 12%. Second, we construct an effective 1D energy density by combining the Mindlin-Reissner kinematics with a nonlinearity in the stress-strain relation. Finally, we establish and solve the governing beam equations to analytically determine the slope of the force-displacement curve in the postbuckling regime. We find, without any adjustable parameters, excellent agreement between the 1D theory, experiments and simulations. Our work extends the understanding of the postbuckling of structures made of wide elastic beams and opens up avenues for the reverse-engineering of instabilities in soft and metamaterials.

  13. The modulation of galactic cosmic rays as described by a three-dimensional drift model

    International Nuclear Information System (INIS)

    Potgieter, M.S.

    1984-01-01

    An outline of the present state of knowledge about the effect of drift on the modulation of galactic cosmic rays is given. Various observations related to the reversal of the solar magnetic field polarity are discussed. Comprehensive numerical solutions of the steady-state cosmic-ray transport equation in an axially-symmetric three-dimensional heliosphere, including drift are presented. This is an extention of the continuing effort of the past six years to understand the effect and importance of drift on the transport of galactic cosmic rays in the heliosphere. A flat neutral sheet which coincides with the equatorial plane is assumed. A general method of calculating the drift velocity in the neutral sheet including that used previously by other authors is presented. The effect of changing various modulation parameters on the drift solutions are illustrated in detail. The real significance of drift is illustrated by using Gaussian input spectra on the modulation boundary. A carefully selected set of modulation parameters is used to illustrate to what extent a drift model can explain prominent observational features. It is concluded that drift is important in in the process of cosmic-ray transport and must as such be considered in all modulation studies, but that it is not overwhelmingly dominant as previously anticipated

  14. Multilevel regression models describing regional patterns of invertebrate and algal responses to urbanization across the USA

    Science.gov (United States)

    Cuffney, T.F.; Kashuba, R.; Qian, S.S.; Alameddine, I.; Cha, Y.K.; Lee, B.; Coles, J.F.; McMahon, G.

    2011-01-01

    Multilevel hierarchical regression was used to examine regional patterns in the responses of benthic macroinvertebrates and algae to urbanization across 9 metropolitan areas of the conterminous USA. Linear regressions established that responses (intercepts and slopes) to urbanization of invertebrates and algae varied among metropolitan areas. Multilevel hierarchical regression models were able to explain these differences on the basis of region-scale predictors. Regional differences in the type of land cover (agriculture or forest) being converted to urban and climatic factors (precipitation and air temperature) accounted for the differences in the response of macroinvertebrates to urbanization based on ordination scores, total richness, Ephemeroptera, Plecoptera, Trichoptera richness, and average tolerance. Regional differences in climate and antecedent agriculture also accounted for differences in the responses of salt-tolerant diatoms, but differences in the responses of other diatom metrics (% eutraphenic, % sensitive, and % silt tolerant) were best explained by regional differences in soils (mean % clay soils). The effects of urbanization were most readily detected in regions where forest lands were being converted to urban land because agricultural development significantly degraded assemblages before urbanization and made detection of urban effects difficult. The effects of climatic factors (temperature, precipitation) on background conditions (biogeographic differences) and rates of response to urbanization were most apparent after accounting for the effects of agricultural development. The effects of climate and land cover on responses to urbanization provide strong evidence that monitoring, mitigation, and restoration efforts must be tailored for specific regions and that attainment goals (background conditions) may not be possible in regions with high levels of prior disturbance (e.g., agricultural development). ?? 2011 by The North American

  15. A holistic conceptual framework model to describe medication adherence in and guide interventions in diabetes mellitus.

    Science.gov (United States)

    Jaam, Myriam; Awaisu, Ahmed; Mohamed Ibrahim, Mohamed Izham; Kheir, Nadir

    2018-04-01

    Nonadherence to medications in patients with diabetes, which results in poor treatment outcomes and increased healthcare costs, is commonly reported globally. Factors associated with medication adherence have also been widely studied. However, a clear and comprehensive, disease-specific conceptual framework model that captures all possible factors has not been established. This study aimed to develop a conceptual framework that addresses the complex network of barriers to medication adherence in patients with diabetes. Fourteen databases and grey literature sources were systematically searched for systematic reviews reporting barriers to medication adherence in patients with diabetes. A thematic approach was used to categorize all identified barriers from the reviews and to create a matrix representing the complex network and relations of the different barriers. Eighteen systematic reviews were identified and used for the development of the conceptual framework. Overall, six major themes emerged: patient-, medication-, disease-, provider-, system-, and societal-related factors. Each of these themes was further classified into different sub-categories. It was noted that most interactions were identified to be within the patient-related factors, which not only interact with other themes but also within the same theme. Patient's demographics as well as cultural beliefs were the most notable factors in terms of interactions with other categories and themes. The intricate network and interaction of factors identified between different themes and within individual themes indicate the complexity of the problem of adherence. This framework will potentially enhance the understanding of the complex relation between different barriers for medication adherence in diabetes and will facilitate design of more effective interventions. Future interventions for enhancing medication adherence should look at the overall factors and target multiple themes of barriers to improve patient

  16. A physically-based analytical model to describe effective excess charge for streaming potential generation in saturated porous media

    Science.gov (United States)

    Jougnot, D.; Guarracino, L.

    2016-12-01

    The self-potential (SP) method is considered by most researchers the only geophysical method that is directly sensitive to groundwater flow. One source of SP signals, the so-called streaming potential, results from the presence of an electrical double layer at the mineral-pore water interface. When water flows through the pore space, it gives rise to a streaming current and a resulting measurable electrical voltage. Different approaches have been proposed to predict streaming potentials in porous media. One approach is based on the excess charge which is effectively dragged in the medium by the water flow. Following a recent theoretical framework, we developed a physically-based analytical model to predict the effective excess charge in saturated porous media. In this study, the porous media is described by a bundle of capillary tubes with a fractal pore-size distribution. First, an analytical relationship is derived to determine the effective excess charge for a single capillary tube as a function of the pore water salinity. Then, this relationship is used to obtain both exact and approximated expressions for the effective excess charge at the Representative Elementary Volume (REV) scale. The resulting analytical relationship allows the determination of the effective excess charge as a function of pore water salinity, fractal dimension and hydraulic parameters like porosity and permeability, which are also obtained at the REV scale. This new model has been successfully tested against data from the literature of different sources. One of the main finding of this study is that it provides a mechanistic explanation to the empirical dependence between the effective excess charge and the permeability that has been found by various researchers. The proposed petrophysical relationship also contributes to understand the role of porosity and water salinity on effective excess charge and will help to push further the use of streaming potential to monitor groundwater flow.

  17. Improving student success using predictive models and data visualisations

    Directory of Open Access Journals (Sweden)

    Hanan Ayad

    2012-08-01

    Full Text Available The need to educate a competitive workforce is a global problem. In the US, for example, despite billions of dollars spent to improve the educational system, approximately 35% of students never finish high school. The drop rate among some demographic groups is as high as 50–60%. At the college level in the US only 30% of students graduate from 2-year colleges in 3 years or less and approximately 50% graduate from 4-year colleges in 5 years or less. A basic challenge in delivering global education, therefore, is improving student success. By student success we mean improving retention, completion and graduation rates. In this paper we describe a Student Success System (S3 that provides a holistic, analytical view of student academic progress.1 The core of S3 is a flexible predictive modelling engine that uses machine intelligence and statistical techniques to identify at-risk students pre-emptively. S3 also provides a set of advanced data visualisations for reaching diagnostic insights and a case management tool for managing interventions. S3's open modular architecture will also allow integration and plug-ins with both open and proprietary software. Powered by learning analytics, S3 is intended as an end-to-end solution for identifying at-risk students, understanding why they are at risk, designing interventions to mitigate that risk and finally closing the feedback look by tracking the efficacy of the applied intervention.

  18. Expanding on Successful Concepts, Models, and Organization

    Science.gov (United States)

    If the goal of the AEP framework was to replace existing exposure models or databases for organizing exposure data with a concept, we would share Dr. von Göetz concerns. Instead, the outcome we promote is broader use of an organizational framework for exposure science. The f...

  19. Documenting a best practice model for successful female inmate ...

    African Journals Online (AJOL)

    Documenting a best practice model for successful female inmate and female ex ... of men and women within the prison and correctional services as well as inform and ... and beyond, with scope for transforming it into a robust business model.

  20. Prediction models for successful external cephalic version: a systematic review

    NARCIS (Netherlands)

    Velzel, Joost; de Hundt, Marcella; Mulder, Frederique M.; Molkenboer, Jan F. M.; van der Post, Joris A. M.; Mol, Ben W.; Kok, Marjolein

    2015-01-01

    To provide an overview of existing prediction models for successful ECV, and to assess their quality, development and performance. We searched MEDLINE, EMBASE and the Cochrane Library to identify all articles reporting on prediction models for successful ECV published from inception to January 2015.

  1. Semimechanistic model describing gastric emptying and glucose absorption in healthy subjects and patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Alskär, Oskar; Bagger, Jonatan I; Røge, Rikke M.

    2016-01-01

    The integrated glucose-insulin (IGI) model is a previously published semimechanistic model that describes plasma glucose and insulin concentrations after glucose challenges. The aim of this work was to use knowledge of physiology to improve the IGI model's description of glucose absorption and ga...... model provides a better description and improves the understanding of dynamic glucose tests involving oral glucose....... and gastric emptying after tests with varying glucose doses. The developed model's performance was compared to empirical models. To develop our model, data from oral and intravenous glucose challenges in patients with type 2 diabetes and healthy control subjects were used together with present knowledge...... glucose absorption was superior to linear absorption regardless of the gastric emptying model applied. The semiphysiological model developed performed better than previously published empirical models and allows better understanding of the mechanisms underlying glucose absorption. In conclusion, our new...

  2. A standardised graphic method for describing data privacy frameworks in primary care research using a flexible zone model.

    NARCIS (Netherlands)

    Kuchinke, W.; Ohmann, C.; Verheij, R.A.; Veen, E.B. van; Arvanitis, T.N.; Taweel, A.; Delaney, B.C.

    2014-01-01

    Purpose: To develop a model describing core concepts and principles of data flow, data privacy and confidentiality, in a simple and flexible way, using concise process descriptions and a diagrammatic notation applied to research workflow processes. The model should help to generate robust data

  3. A comparison of macroscopic models describing the collective response of sedimenting rod-like particles in shear flows

    KAUST Repository

    Helzel, Christiane; Tzavaras, Athanasios

    2016-01-01

    We consider a kinetic model, which describes the sedimentation of rod-like particles in dilute suspensions under the influence of gravity, presented in Helzel and Tzavaras (submitted for publication). Here we restrict our considerations to shear flow and consider a simplified situation, where the particle orientation is restricted to the plane spanned by the direction of shear and the direction of gravity. For this simplified kinetic model we carry out a linear stability analysis and we derive two different nonlinear macroscopic models which describe the formation of clusters of higher particle density. One of these macroscopic models is based on a diffusive scaling, the other one is based on a so-called quasi-dynamic approximation. Numerical computations, which compare the predictions of the macroscopic models with the kinetic model, complete our presentation.

  4. A comparison of macroscopic models describing the collective response of sedimenting rod-like particles in shear flows

    KAUST Repository

    Helzel, Christiane

    2016-07-22

    We consider a kinetic model, which describes the sedimentation of rod-like particles in dilute suspensions under the influence of gravity, presented in Helzel and Tzavaras (submitted for publication). Here we restrict our considerations to shear flow and consider a simplified situation, where the particle orientation is restricted to the plane spanned by the direction of shear and the direction of gravity. For this simplified kinetic model we carry out a linear stability analysis and we derive two different nonlinear macroscopic models which describe the formation of clusters of higher particle density. One of these macroscopic models is based on a diffusive scaling, the other one is based on a so-called quasi-dynamic approximation. Numerical computations, which compare the predictions of the macroscopic models with the kinetic model, complete our presentation.

  5. A Comparison of Models Describing Heat Transfer in the Primary Cooling Zone of a Continuous Casting Machine

    Directory of Open Access Journals (Sweden)

    Miłkowska-Piszczek K.

    2015-04-01

    Full Text Available This paper presents the findings of research conducted concerning the determination of thermal boundary conditions for the steel continuous casting process within the primary cooling zone. A cast slab - with dimensions of 1100 mm×220 mm - was analysed, and models described in references were compared with the authors’ model. The presented models were verified on the basis of an industrial database. The research problem was solved with the finite element method using the ProCAST software package.

  6. Establishing a Cloud Computing Success Model for Hospitals in Taiwan

    OpenAIRE

    Lian, Jiunn-Woei

    2017-01-01

    The purpose of this study is to understand the critical quality-related factors that affect cloud computing success of hospitals in Taiwan. In this study, private cloud computing is the major research target. The chief information officers participated in a questionnaire survey. The results indicate that the integration of trust into the information systems success model will have acceptable explanatory power to understand cloud computing success in the hospital. Moreover, information quality...

  7. A STUDY ON THE SUCCESSION MODEL OF FAMILY BUSINESSS

    OpenAIRE

    Hung-Jung Chang; Szu-Ju Lin

    2011-01-01

    Family business has to face issues such as ownership issue, governance structure issue and succession issue, etc. in enterprise development history. Among them, the succession issue is an important transition point in enterprise’s survival and development. It is thus thought of as one of the most important strategic and decision making issues in the enterprise. This article aims at investigating the succession model of Family business. First, reviews are done on the meaning of Family business...

  8. Process health management using success tree and empirical model

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Gyunyoung [Kyung Hee Univ., Yongin (Korea, Republic of); Kim, Suyoung [BNF Technology, Daejeon (Korea, Republic of); Sung, Wounkyoung [Korea South-East Power Co. Ltd., Seoul (Korea, Republic of)

    2012-03-15

    Interests on predictive or condition-based maintenance are heightening in power industries. The ultimate goal of the condition-based maintenance is to prioritize and optimize the maintenance resources by taking a reasonable decision-making process depending op plant's conditions. Such decision-making process should be able to not only observe the deviation from a normal state but also determine the severity or impact of the deviation on different levels such as a component, a system, or a plant. In order to achieve this purpose, a Plant Health Index (PHI) monitoring system was developed, which is operational in more than 10 units of large steam turbine cycles in Korea as well as desalination plants in Saudi Arabia as a proto-type demonstration. The PHI monitoring system has capability to detect whether the deviation between a measured and an estimated parameter which is the result of kernel regression using the accumulated operation data and the current plant boundary conditions (referred as an empirical model) is statistically meaningful. This deviation is converted into a certain index considering the margin to set points which are associated with safety. This index is referred as a PHI and the PHIs can be monitored for an individual parameter as well as a component, system, or plant level. In order to organize the PHIs at the component, system, or plant level, a success tree was developed. At the top of the success tree, the PHIs nodes in the middle of the success tree, the PHIs represent the health status of a component or a system. The concept and definition of the PHI, the key methodologies, the architecture of the developed system, and a practical case of using the PHI monitoring system are described in this article.

  9. Process health management using success tree and empirical model

    International Nuclear Information System (INIS)

    Heo, Gyunyoung; Kim, Suyoung; Sung, Wounkyoung

    2012-01-01

    Interests on predictive or condition-based maintenance are heightening in power industries. The ultimate goal of the condition-based maintenance is to prioritize and optimize the maintenance resources by taking a reasonable decision-making process depending op plant's conditions. Such decision-making process should be able to not only observe the deviation from a normal state but also determine the severity or impact of the deviation on different levels such as a component, a system, or a plant. In order to achieve this purpose, a Plant Health Index (PHI) monitoring system was developed, which is operational in more than 10 units of large steam turbine cycles in Korea as well as desalination plants in Saudi Arabia as a proto-type demonstration. The PHI monitoring system has capability to detect whether the deviation between a measured and an estimated parameter which is the result of kernel regression using the accumulated operation data and the current plant boundary conditions (referred as an empirical model) is statistically meaningful. This deviation is converted into a certain index considering the margin to set points which are associated with safety. This index is referred as a PHI and the PHIs can be monitored for an individual parameter as well as a component, system, or plant level. In order to organize the PHIs at the component, system, or plant level, a success tree was developed. At the top of the success tree, the PHIs nodes in the middle of the success tree, the PHIs represent the health status of a component or a system. The concept and definition of the PHI, the key methodologies, the architecture of the developed system, and a practical case of using the PHI monitoring system are described in this article

  10. The Achieving Success Everyday Group Counseling Model: Implications for Professional School Counselors

    Science.gov (United States)

    Steen, Sam; Henfield, Malik S.; Booker, Beverly

    2014-01-01

    This article presents the Achieving Success Everyday (ASE) group counseling model, which is designed to help school counselors integrate students' academic and personal-social development into their group work. We first describe this group model in detail and then offer one case example of a middle school counselor using the ASE model to conduct a…

  11. Validation of a Simulation Model Describing the Glucose-Insulin-Glucagon Pharmacodynamics in Patients with Type 1 Diabetes

    DEFF Research Database (Denmark)

    Wendt, Sabrina Lyngbye; Ranjan, Ajenthen; Møller, Jan Kloppenborg

    Currently, no consensus exists on a model describing endogenous glucose production (EGP) as a function of glucagon concentrations. Reliable simulations to determine the glucagon dose preventing or treating hypoglycemia or to tune a dual-hormone artificial pancreas control algorithm need a validat...

  12. Biological Effectiveness and Application of Heavy Ions in Radiation Therapy Described by a Physical and Biological Model

    DEFF Research Database (Denmark)

    Olsen, Kjeld J.; Hansen, Johnny W.

    is inadequately described by an RBE-factor, whereas the complete formulation of the probability of survival must be used, as survival depends on both radiation quality and dose. The theoretical model of track structure can be used in dose-effect calculations for neutron-, high-LET, and low-LET radiation applied...... simultaneously in therapy....

  13. A standardised graphic method for describing data privacy frameworks in primary care research using a flexible zone model.

    Science.gov (United States)

    Kuchinke, Wolfgang; Ohmann, Christian; Verheij, Robert A; van Veen, Evert-Ben; Arvanitis, Theodoros N; Taweel, Adel; Delaney, Brendan C

    2014-12-01

    To develop a model describing core concepts and principles of data flow, data privacy and confidentiality, in a simple and flexible way, using concise process descriptions and a diagrammatic notation applied to research workflow processes. The model should help to generate robust data privacy frameworks for research done with patient data. Based on an exploration of EU legal requirements for data protection and privacy, data access policies, and existing privacy frameworks of research projects, basic concepts and common processes were extracted, described and incorporated into a model with a formal graphical representation and a standardised notation. The Unified Modelling Language (UML) notation was enriched by workflow and own symbols to enable the representation of extended data flow requirements, data privacy and data security requirements, privacy enhancing techniques (PET) and to allow privacy threat analysis for research scenarios. Our model is built upon the concept of three privacy zones (Care Zone, Non-care Zone and Research Zone) containing databases, data transformation operators, such as data linkers and privacy filters. Using these model components, a risk gradient for moving data from a zone of high risk for patient identification to a zone of low risk can be described. The model was applied to the analysis of data flows in several general clinical research use cases and two research scenarios from the TRANSFoRm project (e.g., finding patients for clinical research and linkage of databases). The model was validated by representing research done with the NIVEL Primary Care Database in the Netherlands. The model allows analysis of data privacy and confidentiality issues for research with patient data in a structured way and provides a framework to specify a privacy compliant data flow, to communicate privacy requirements and to identify weak points for an adequate implementation of data privacy. Copyright © 2014 Elsevier Ireland Ltd. All rights

  14. Modelling the effect of food availability on recruitment success of ...

    African Journals Online (AJOL)

    Modelling the effect of food availability on recruitment success of Cape anchovy ichthyoplankton in ... To characterise the recruitment dynamics of Cape anchovy ichthyoplankton, we used an individual-based ... AJOL African Journals Online.

  15. Empirical evaluation of a forecasting model for successful facilitation ...

    African Journals Online (AJOL)

    During 2000 the annual Facilitator Customer Satisfaction Survey was ... the forecasting model is successful concerning the CSI value and a high positive linear ... namely that of human behaviour to incorporate other influences than just the ...

  16. Evidence in Support of the Independent Channel Model Describing the Sensorimotor Control of Human Stance Using a Humanoid Robot.

    Science.gov (United States)

    Pasma, Jantsje H; Assländer, Lorenz; van Kordelaar, Joost; de Kam, Digna; Mergner, Thomas; Schouten, Alfred C

    2018-01-01

    The Independent Channel (IC) model is a commonly used linear balance control model in the frequency domain to analyze human balance control using system identification and parameter estimation. The IC model is a rudimentary and noise-free description of balance behavior in the frequency domain, where a stable model representation is not guaranteed. In this study, we conducted firstly time-domain simulations with added noise, and secondly robot experiments by implementing the IC model in a real-world robot (PostuRob II) to test the validity and stability of the model in the time domain and for real world situations. Balance behavior of seven healthy participants was measured during upright stance by applying pseudorandom continuous support surface rotations. System identification and parameter estimation were used to describe the balance behavior with the IC model in the frequency domain. The IC model with the estimated parameters from human experiments was implemented in Simulink for computer simulations including noise in the time domain and robot experiments using the humanoid robot PostuRob II. Again, system identification and parameter estimation were used to describe the simulated balance behavior. Time series, Frequency Response Functions, and estimated parameters from human experiments, computer simulations, and robot experiments were compared with each other. The computer simulations showed similar balance behavior and estimated control parameters compared to the human experiments, in the time and frequency domain. Also, the IC model was able to control the humanoid robot by keeping it upright, but showed small differences compared to the human experiments in the time and frequency domain, especially at high frequencies. We conclude that the IC model, a descriptive model in the frequency domain, can imitate human balance behavior also in the time domain, both in computer simulations with added noise and real world situations with a humanoid robot. This

  17. Evidence in Support of the Independent Channel Model Describing the Sensorimotor Control of Human Stance Using a Humanoid Robot

    Directory of Open Access Journals (Sweden)

    Jantsje H. Pasma

    2018-03-01

    Full Text Available The Independent Channel (IC model is a commonly used linear balance control model in the frequency domain to analyze human balance control using system identification and parameter estimation. The IC model is a rudimentary and noise-free description of balance behavior in the frequency domain, where a stable model representation is not guaranteed. In this study, we conducted firstly time-domain simulations with added noise, and secondly robot experiments by implementing the IC model in a real-world robot (PostuRob II to test the validity and stability of the model in the time domain and for real world situations. Balance behavior of seven healthy participants was measured during upright stance by applying pseudorandom continuous support surface rotations. System identification and parameter estimation were used to describe the balance behavior with the IC model in the frequency domain. The IC model with the estimated parameters from human experiments was implemented in Simulink for computer simulations including noise in the time domain and robot experiments using the humanoid robot PostuRob II. Again, system identification and parameter estimation were used to describe the simulated balance behavior. Time series, Frequency Response Functions, and estimated parameters from human experiments, computer simulations, and robot experiments were compared with each other. The computer simulations showed similar balance behavior and estimated control parameters compared to the human experiments, in the time and frequency domain. Also, the IC model was able to control the humanoid robot by keeping it upright, but showed small differences compared to the human experiments in the time and frequency domain, especially at high frequencies. We conclude that the IC model, a descriptive model in the frequency domain, can imitate human balance behavior also in the time domain, both in computer simulations with added noise and real world situations with a

  18. Building a Model of Successful Collaborative Learning for Company Innovativeness

    Directory of Open Access Journals (Sweden)

    Agata Sudolska

    2014-01-01

    Full Text Available The aim of the paper is to develop a model of successful collaborative learning for company innovativeness. First of all, the paper explores the issue of inter-firm learning, focusing its attention on collaborative learning. Secondly, inter-firm learning relationships are considered. Thirdly, the ex ante conditions of collaborative learning and the intra-organizational enhancers of inter-firm learning processes are studied. Finally, a model of the critical success factors for collaborative learning is developed.

  19. Is coronene better described by Clar's aromatic π-sextet model or by the AdNDP representation?

    Science.gov (United States)

    Kumar, Anand; Duran, Miquel; Solà, Miquel

    2017-07-05

    The bonding patterns in coronene are complicated and controversial as denoted by the lack of consensus of how its electronic structure should be described. Among the different proposed descriptions, the two most representative are those generated by Clar's aromatic π-sextet and adaptative natural density partitioning (AdNDP) models. Quantum-chemical calculations at the density functional theory level are performed to evaluate the model that gives a better representation of coronene. To this end, we analyse the molecular structure of coronene, we estimate the aromaticity of its inner and outer rings using various local aromaticity descriptors, and we assess its chemical reactivity from the study of the Diels-Alder reaction with cyclopentadiene. Results obtained are compared with those computed for naphthalene and phenanthrene. Our conclusion is that Clar's π-sextet model provides the representation of coronene that better describes the physicochemical behavior of this molecule. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  20. KANDY - a numerical model to describe phenomena, which - in a heated and voided fuel element of an LMFBR - may occur

    International Nuclear Information System (INIS)

    Thurnay, K.

    1984-02-01

    Kandy is a model developed to describe the essential destructionphenomena of the fuel elements of an LMFBR. The fuel element is assumed to be a voided one, in which the heat generation is still going on. The main process to be modeled is the melting/bursting/evaporating of parts of the fuel pins and the subsequent dislocation of these materials in the coolant channel. The work presented summarizes the assumptions constituting the model, develops the corresponding equations of motion and describes the procedure, turning these into a system of difference-equations ready for coding. As a final part results of a testcase calculation with the Kandy-code are presentend and interpreted. (orig.) [de

  1. Establishing a Cloud Computing Success Model for Hospitals in Taiwan

    Science.gov (United States)

    Lian, Jiunn-Woei

    2017-01-01

    The purpose of this study is to understand the critical quality-related factors that affect cloud computing success of hospitals in Taiwan. In this study, private cloud computing is the major research target. The chief information officers participated in a questionnaire survey. The results indicate that the integration of trust into the information systems success model will have acceptable explanatory power to understand cloud computing success in the hospital. Moreover, information quality and system quality directly affect cloud computing satisfaction, whereas service quality indirectly affects the satisfaction through trust. In other words, trust serves as the mediator between service quality and satisfaction. This cloud computing success model will help hospitals evaluate or achieve success after adopting private cloud computing health care services. PMID:28112020

  2. Establishing a Cloud Computing Success Model for Hospitals in Taiwan.

    Science.gov (United States)

    Lian, Jiunn-Woei

    2017-01-01

    The purpose of this study is to understand the critical quality-related factors that affect cloud computing success of hospitals in Taiwan. In this study, private cloud computing is the major research target. The chief information officers participated in a questionnaire survey. The results indicate that the integration of trust into the information systems success model will have acceptable explanatory power to understand cloud computing success in the hospital. Moreover, information quality and system quality directly affect cloud computing satisfaction, whereas service quality indirectly affects the satisfaction through trust. In other words, trust serves as the mediator between service quality and satisfaction. This cloud computing success model will help hospitals evaluate or achieve success after adopting private cloud computing health care services.

  3. Establishing a Cloud Computing Success Model for Hospitals in Taiwan

    Directory of Open Access Journals (Sweden)

    Jiunn-Woei Lian PhD

    2017-01-01

    Full Text Available The purpose of this study is to understand the critical quality-related factors that affect cloud computing success of hospitals in Taiwan. In this study, private cloud computing is the major research target. The chief information officers participated in a questionnaire survey. The results indicate that the integration of trust into the information systems success model will have acceptable explanatory power to understand cloud computing success in the hospital. Moreover, information quality and system quality directly affect cloud computing satisfaction, whereas service quality indirectly affects the satisfaction through trust. In other words, trust serves as the mediator between service quality and satisfaction. This cloud computing success model will help hospitals evaluate or achieve success after adopting private cloud computing health care services.

  4. A new model describing the curves for repair of both DNA double-strand breaks and chromosome damage

    International Nuclear Information System (INIS)

    Foray, N.; Badie, C.; Alsbeih, G.; Malaise, E.P.; Fertil, B.

    1996-01-01

    A review of reports dealing with fittings of the data for repair of DNA double-strand breaks (DSBs) and excess chromosome fragments (ECFs) shows that several models are used to fit the repair curves. Since DSBs and ECFs are correleated, it is worth developing a model describing both phenomena. The curve-fitting models used most extensively, the two repair half-times model for DSBs and the monoexponential plus residual model for ECFs, appear to be too inflexible to describe the repair curves for both DSBs and ECFs. We have therefore developed a new concept based on a variable repair half-time. According to this concept, the repair curve is continuously bending and dependent on time and probably reflects a continuous spectrum of damage repairability. The fits of the curves for DSB repair to the variable repair half-time and the variable repair half-time plus residual models were compared to those obtained with the two half-times plus residual and two half-times models. Similarly, the fits of the curves for ECF repair to the variable repair half-time and variable half-time plus residual models were compared to that obtained with the monoexponential plus residual model. The quality of fit and the dependence of adjustable parameters on the portion of the curve fitted were used as comparison criteria. We found that: (a) It is useful to postulate the existence of a residual term for unrepairable lesions, regardless of the model adopted. (b) With the two cell lines tested (a normal and a hypersensitive one), data for both DSBs and ECTs are best fitted to the variable repair half-time plus residual model, whatever the repair time range. 47 refs., 3 figs., 3 tabs

  5. DaMoScope and its internet graphics for the visual control of adjusting mathematical models describing experimental data

    International Nuclear Information System (INIS)

    Belousov, V. I.; Ezhela, V. V.; Kuyanov, Yu. V.; Tkachenko, N. P.

    2015-01-01

    The experience of using the dynamic atlas of the experimental data and mathematical models of their description in the problems of adjusting parametric models of observable values depending on kinematic variables is presented. The functional possibilities of an image of a large number of experimental data and the models describing them are shown by examples of data and models of observable values determined by the amplitudes of elastic scattering of hadrons. The Internet implementation of an interactive tool DaMoScope and its interface with the experimental data and codes of adjusted parametric models with the parameters of the best description of data are schematically shown. The DaMoScope codes are freely available

  6. DaMoScope and its internet graphics for the visual control of adjusting mathematical models describing experimental data

    Science.gov (United States)

    Belousov, V. I.; Ezhela, V. V.; Kuyanov, Yu. V.; Tkachenko, N. P.

    2015-12-01

    The experience of using the dynamic atlas of the experimental data and mathematical models of their description in the problems of adjusting parametric models of observable values depending on kinematic variables is presented. The functional possibilities of an image of a large number of experimental data and the models describing them are shown by examples of data and models of observable values determined by the amplitudes of elastic scattering of hadrons. The Internet implementation of an interactive tool DaMoScope and its interface with the experimental data and codes of adjusted parametric models with the parameters of the best description of data are schematically shown. The DaMoScope codes are freely available.

  7. DaMoScope and its internet graphics for the visual control of adjusting mathematical models describing experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Belousov, V. I.; Ezhela, V. V.; Kuyanov, Yu. V., E-mail: Yu.Kuyanov@gmail.com; Tkachenko, N. P. [Institute for High Energy Physics, National Research Center Kurchatov Institute, COMPAS Group (Russian Federation)

    2015-12-15

    The experience of using the dynamic atlas of the experimental data and mathematical models of their description in the problems of adjusting parametric models of observable values depending on kinematic variables is presented. The functional possibilities of an image of a large number of experimental data and the models describing them are shown by examples of data and models of observable values determined by the amplitudes of elastic scattering of hadrons. The Internet implementation of an interactive tool DaMoScope and its interface with the experimental data and codes of adjusted parametric models with the parameters of the best description of data are schematically shown. The DaMoScope codes are freely available.

  8. A New Model for Describing the Rheological Behavior of Heavy and Extra Heavy Crude Oils in the Presence of Nanoparticles

    Directory of Open Access Journals (Sweden)

    Esteban A. Taborda

    2017-12-01

    Full Text Available The present work proposes for the first time a mathematical model for describing the rheological behavior of heavy and extra-heavy crude oils in the presence of nanoparticles. This model results from the combination of two existing mathematical models. The first one applies to the rheology of pseudoplastic substances, i.e., the Herschel-Bulkley model. The second one was previously developed by our research group to model the rheology of suspensions, namely the modified Pal and Rhodes model. The proposed model is applied to heavy and extra heavy crude oils in the presence of nanoparticles, considering the effects of nanoparticles concentration and surface chemical nature, temperature, and crude oil type. All the experimental data evaluated exhibited compelling goodness of fitting, and the physical parameters in the model follow correlate well with variations in viscosity. The new model is dependent of share rate and opens new possibilities for phenomenologically understanding viscosity reduction in heavy crude by adding solid nanoparticles and favoring the scale-up in enhanced oil recovery (EOR and/or improved oil recovery (IOR process.

  9. Evaluation and Validation of a TCAT Model to Describe Non-Dilute Flow and Species Transport in Porous Media

    Science.gov (United States)

    Weigand, T. M.; Harrison, E.; Miller, C. T.

    2017-12-01

    A thermodynamically constrained averaging theory (TCAT) model has been developed to simulate non-dilute flow and species transport in porous media. This model has the advantages of a firm connection between the microscale, or pore scale, and the macroscale; a thermodynamically consistent basis; the explicit inclusion of dissipative terms that arise from spatial gradients in pressure and chemical activity; and the ability to describe both high and low concentration displacement. The TCAT model has previously been shown to provide excellent agreement for a set of laboratory data and outperformed existing macroscale models that have been used for non-dilute flow and transport. The examined experimental dataset consisted of stable brine displacements for a large range of fluid properties. This dataset however only examined one type of porous media and had a fixed flow rate for all experiments. In this work, the TCAT model is applied to a dataset that consists of two different porous media types, constant head and flow rate conditions, varying resident fluid concentrations, and internal probes that measured the pressure and salt mass fraction. Parameter estimation is performed on a subset of the experimental data for the TCAT model as well as other existing non-dilute flow and transport models. The optimized parameters are then used for forward simulations and the accuracy of the models is compared.

  10. A Physically Based Analytical Model to Describe Effective Excess Charge for Streaming Potential Generation in Water Saturated Porous Media

    Science.gov (United States)

    Guarracino, L.; Jougnot, D.

    2018-01-01

    Among the different contributions generating self-potential, the streaming potential is of particular interest in hydrogeology for its sensitivity to water flow. Estimating water flux in porous media using streaming potential data relies on our capacity to understand, model, and upscale the electrokinetic coupling at the mineral-solution interface. Different approaches have been proposed to predict streaming potential generation in porous media. One of these approaches is the flux averaging which is based on determining the excess charge which is effectively dragged in the medium by water flow. In this study, we develop a physically based analytical model to predict the effective excess charge in saturated porous media using a flux-averaging approach in a bundle of capillary tubes with a fractal pore size distribution. The proposed model allows the determination of the effective excess charge as a function of pore water ionic concentration and hydrogeological parameters like porosity, permeability, and tortuosity. The new model has been successfully tested against different set of experimental data from the literature. One of the main findings of this study is the mechanistic explanation to the empirical dependence between the effective excess charge and the permeability that has been found by several researchers. The proposed model also highlights the link to other lithological properties, and it is able to reproduce the evolution of effective excess charge with electrolyte concentrations.

  11. Users' guide to system dynamics model describing Coho salmon survival in Olema Creek, Point Reyes National Seashore, Marin County, California

    Science.gov (United States)

    Woodward, Andrea; Torregrosa, Alicia; Madej, Mary Ann; Reichmuth, Michael; Fong, Darren

    2014-01-01

    The system dynamics model described in this report is the result of a collaboration between U.S. Geological Survey (USGS) scientists and National Park Service (NPS) San Francisco Bay Area Network (SFAN) staff, whose goal was to develop a methodology to integrate inventory and monitoring data to better understand ecosystem dynamics and trends using salmon in Olema Creek, Marin County, California, as an example case. The SFAN began monitoring multiple life stages of coho salmon (Oncorhynchus kisutch) in Olema Creek during 2003 (Carlisle and others, 2013), building on previous monitoring of spawning fish and redds. They initiated water-quality and habitat monitoring, and had access to flow and weather data from other sources. This system dynamics model of the freshwater portion of the coho salmon life cycle in Olema Creek integrated 8 years of existing monitoring data, literature values, and expert opinion to investigate potential factors limiting survival and production, identify data gaps, and improve monitoring and restoration prescriptions. A system dynamics model is particularly effective when (1) data are insufficient in time series length and/or measured parameters for a statistical or mechanistic model, and (2) the model must be easily accessible by users who are not modelers. These characteristics helped us meet the following overarching goals for this model: Summarize and synthesize NPS monitoring data with data and information from other sources to describe factors and processes affecting freshwater survival of coho salmon in Olema Creek. Provide a model that can be easily manipulated to experiment with alternative values of model parameters and novel scenarios of environmental drivers. Although the model describes the ecological dynamics of Olema Creek, these dynamics are structurally similar to numerous other coastal streams along the California coast that also contain anadromous fish populations. The model developed for Olema can be used, at least as a

  12. An analytical mechanical model to describe the response of NiTi rotary endodontic files in a curved root canal

    International Nuclear Information System (INIS)

    Leroy, Agnès Marie Françoise; Bahia, Maria Guiomar de Azevedo; Ehrlacher, Alain; Buono, Vicente Tadeu Lopes

    2012-01-01

    Aim: To build a mathematical model describing the mechanical behavior of NiTi rotary files while they are rotating in a root canal. Methodology: The file was seen as a beam undergoing large transformations. The instrument was assumed to be rotating steadily in the root canal, and the geometry of the canal was considered as a known parameter of the problem. The formulae of large transformations mechanics then allowed the calculation of the Green–Lagrange strain field in the file. The non-linear mechanical behavior of NiTi was modeled as a continuous piecewise linear function, assuming that the material did not reach plastic deformation. Criteria locating the changes of behavior of NiTi were established and the tension field in the file, and the external efforts applied on it were calculated. The unknown variable of torsion was deduced from the equilibrium equation system using a Coulomb contact law which solved the problem on a cycle of rotation. Results: In order to verify that the model described well reality, three-point bending experiments were managed on superelastic NiTi wires, whose results were compared to the theoretical ones. It appeared that the model gave a good mentoring of the empirical results in the range of bending angles that interested us. Conclusions: Knowing the geometry of the root canal, one is now able to write the equations of the strain and stress fields in the endodontic instrument, and to quantify the impact of each macroscopic parameter of the problem on its response. This should be useful to predict failure of the files under rotating bending fatigue, and to optimize the geometry of the files. - Highlights: ► A mechanical model of the behavior of a NiTi endodontic instrument was developed. ► The model was validated with results of three-point bending tests on NiTi wires. ► The model is appropriate for the optimization of instruments' geometry.

  13. Evaluation of a cross contamination model describing transfer of Salmonella spp. and Listeria monocytogenes during grinding of pork and beef.

    Science.gov (United States)

    Møller, C O A; Sant'Ana, A S; Hansen, S K H; Nauta, M J; Silva, L P; Alvarenga, V O; Maffei, D; Silva, F F P; Lopes, J T; Franco, B D G M; Aabo, S; Hansen, T B

    2016-06-02

    In a previous study, a model was developed to describe the transfer and survival of Salmonella during grinding of pork (Møller, C.O.A., Nauta, M.J., Christensen, B.B., Dalgaard, P., Hansen, T.B., 2012. Modelling transfer of Salmonella typhimurium DT104 during simulation of grinding of pork. Journal of Applied Microbiology 112 (1), 90-98). The robustness of this model is now evaluated by studying its performance for predicting the transfer and survival of Salmonella spp. and Listeria monocytogenes during grinding of different types of meat (pork and beef), using two different grinders, different sizes and different numbers of pieces of meats to be ground. A total of 19 grinding trials were collected. Acceptable Simulation Zone (ASZ), visual inspection of the data, Quantitative Microbiological Risk Assessment (QMRA), as well as the Total Transfer Potential (TTP) were used as approaches to evaluate model performance and to access the quality of the cross contamination model predictions. Using the ASZ approach and considering that 70% of the observed counts have to be inside a defined acceptable zone of ±0.5 log10CFU per portion, it was found that the cross contamination parameters suggested by Møller et al. (2012) were not able to describe all 19 trials. However, for each of the collected grinding trials, the transfer event was well described when fitted to the model structure proposed by Møller et al. (2012). Parameter estimates obtained by fitting observed trials performed at different conditions, such as size and number of pieces of meat to be ground, may not be applied to describe cross contamination of unlike processing. Nevertheless, the risk estimates, as well as the TTP, revealed that the risk of disease may be reduced when the grinding of meat is performed in a grinder made of stainless steel (for all surfaces in contact with the meat), using a well-sharpened knife and holding at room temperatures lower than 4°C. Copyright © 2016 Elsevier B.V. All

  14. The Polyakov, Nambu and Jona-Lasinio model and its applications to describe the sub-nuclear particles

    International Nuclear Information System (INIS)

    Blanquier, E.

    2013-01-01

    To study the high energy nuclear physics and the associated phenomenon, as the quark-gluon plasma / hadronic matter phase transition, the Nambu and Jona-Lasinio model (NJL) appears as an interesting alternative to the Quantum Chromodynamics, not solvable at the considered energies. Indeed, the NJL model allows the description of quarks physics, at finite temperatures and densities. Furthermore, in order to try to correct a limitation of the NJL model, i.e. the absence of confinement, it was proposed a coupling of the quarks/antiquarks to a Polyakov loop, forming the PNJL model. The objective of this thesis is to see the possibilities offered by the NJL and PNJL models, to describe relevant sub-nuclear particles (quarks, mesons, diquarks and baryons), to study their interactions, and to proceed to a dynamical study involving these particles. After a recall of the useful tools, we modeled the u, d, s effective quarks and the mesons. Then, we described the baryons as quarks-diquarks bound states. A part of the work concerned the calculations of the cross-sections associated to the possible reactions implying these particles. Then, we incorporated these results in a computer code, in order to study the cooling of a quarks/antiquarks plasma and its hadronization. In this study, each particle evolves in a system in which the temperature and the densities are local parameters. We have two types of interactions: one due to the collisions, and the other is a remote interaction, notably between quarks. Finally, we studied the properties of our approach: qualities, limitations, and possible evolutions. (author)

  15. The Drivers of Success in Business Model Transformation

    Directory of Open Access Journals (Sweden)

    Nenad Savič

    2016-01-01

    Full Text Available Existing empirical literature on business models is still inconclusive about the key drivers of successful business model transformation. The paper explores this issue by using a single longitudinal case study design in combination with grounded theory approach on a medium-sized, high-tech and globally oriented company. Based on on-site visits, interviews and secondary documentation data analysis, the study identifies six generic drivers of successful business model transformation: transformational leadership, discovery driven decision-making, industry improvement – customer specific orientation, content-oriented communication, self-initiative collaborators, and phased separation strategy. The new drivers supplement our existing knowledge on how successful transformation takes place and add to existing drivers, while extensive discussion of their implications may help the managers to execute business transformations more effectively.

  16. Learned helplessness or expectancy-value? A psychological model for describing the experiences of different categories of unemployed people.

    Science.gov (United States)

    García Rodríguez, Y

    1997-06-01

    Various studies have explored the relationships between unemployment and expectation of success, commitment to work, motivation, causal attributions, self-esteem and depression. A model is proposed that assumes the relationships between these variables are moderated by (a) whether or not the unemployed individual is seeking a first job and (b) age. It is proposed that for the unemployed who are seeking their first job (seekers) the relationships among these variables will be consistent with expectancy-value theory, but for those who have had a previous job (losers), the relationships will be more consistent with learned helplessness theory. It is further assumed that within this latter group the young losers will experience "universal helplessness" whereas the adult losers will experience "personal helplessness".

  17. Evaluation of a cross contamination model describing transfer of salmonella spp. and listeria monocytogenes during grinding of pork and beef

    DEFF Research Database (Denmark)

    Møller, Cleide Oliveira de Almeida; Hansen, Tina Beck; Aabo, Søren

    2015-01-01

    Introduction: The cross contamination model (Møller et al. 2012) was evaluated to investigate its capability of describing transfer of Salmonella spp. and Listeria monocytogenes during grinding of pork and beef of varying sizes (50 – 324 g) and numbers of pieces to be ground (10 – 100), in two...... processing. QMRA risk estimates and TTP both revealed that risk attribution from grinding was mainly influenced by sharpness of grinder knife > specific grinder > grinding temperature whereas the specific pathogen was of minor importance....

  18. Biological effectiveness and application of heavy ions in radiation therapy described by a physical and biological model

    International Nuclear Information System (INIS)

    Olsen, K.J.; Hansen, J.W.

    1982-12-01

    A description is given of the physical basis for applying track structure theory in the determination of the effectiveness of heavy-ion irradiation of single- and multi-hit target systems. It will be shown that for applying the theory to biological systems the effectiveness of heavy-ion irradiation is inadequately described by an RBE-factor, whereas the complete formulation of the probability of survival must be used, as survival depends on both radiation quality and dose. The theoretical model of track structure can be used in dose-effect calculations for neutron-, high-LET, and low-LET radiation applied simultaneously in therapy. (author)

  19. A dendrochronological analysis of a disturbance-succession model for oak-pine forests of the Appalachian Mountains, USA

    Science.gov (United States)

    Patrick H. Brose; Thomas A. Waldrop

    2010-01-01

    Disturbance-succession models describe the relationship between the disturbance regime and the dominant tree species of a forest type. Such models are useful tools in ecosystem management and restoration, provided they are accurate. We tested a disturbance-succession model for the oak-pine (Quercus spp. - Pinus spp.) forests of the...

  20. Description of Success: A Four-Teacher Instructional Model.

    Science.gov (United States)

    Reed, Dianne

    This study described a four-teacher instructional model in operation at an elementary school, noting the perceptions of fourth grade students, parents, and teachers regarding the model. The model encompassed teaming, block scheduling, departmentalization of subjects, integrated/interdisciplinary instruction, and in-depth instruction in each…

  1. Electronic Commerce Success Model: A Search for Multiple Criteria

    Directory of Open Access Journals (Sweden)

    Didi Achjari

    2004-01-01

    Full Text Available The current study attempts to develop and examine framework of e-commerce success. In order to obtain comprehensive and robust measures, the framework accomodates key factors that are identified in the literature concerning the success of electronic commerce. The structural model comprises of four exogenous variables (Internal Driver, Internal Impediment, External Driver and Exgternal Impediment and one endogenous variable (Electornic Commerce Success eith 24 observed variables. The study that was administered within large Australian companies using questionaire survey concluded that benefits for both internal organization and external parties from the use of e-commerce were the main factor tro predict perceived and/or expected success of electronic commerce.

  2. A Novel Dynamic Model Describing the Spread of the MERS-CoV and the Expression of Dipeptidyl Peptidase 4

    Directory of Open Access Journals (Sweden)

    Siming Tang

    2017-01-01

    Full Text Available The Middle East respiratory syndrome (MERS coronavirus, a newly identified pathogen, causes severe pneumonia in humans. MERS is caused by a coronavirus known as MERS-CoV, which attacks the respiratory system. The recently defined receptor for MERS-CoV, dipeptidyl peptidase 4 (DPP4, is generally expressed in endothelial and epithelial cells and has been shown to be present on cultured human nonciliated bronchiolar epithelium cells. In this paper, a class of novel four-dimensional dynamic model describing the infection of MERS-CoV is given, and then global stability of the equilibria of the model is discussed. Our results show that the spread of MERS-CoV can also be controlled by decreasing the expression rate of DPP4.

  3. A mathematical model describing the glycemic response of diabetic patients to meal and i.v. infusion of insulin.

    Science.gov (United States)

    Fabietti, P G; Calabrese, G; Iorio, M; Bistoni, S; Brunetti, P; Sarti, E; Benedetti, M M

    2001-10-01

    Nine type 1 diabetic patients were studied for 24 hours. During this period they were given three calibrated meals. The glycemia was feedback-controlled by means of an artificial pancreas. The blood concentration of glucose and the infusion speed of the insulin were measured every minute. The experimental data referring to each of the three meals were used to estimate the parameters of a mathematical model suitable for describing the glycemic response of diabetic patients at meals and at the i.v. infusion of exogenous insulin. From the estimate a marked dispersion of the parameters was found, both interindividual and intraindividual. Nevertheless the models thus obtained seem to be usable for the synthesis of a feedback controller, especially in view of creating a portable artificial pancreas that now seems possible owing to the realization (so far experimental) of sufficiently reliable glucose concentration sensors.

  4. An analytical mechanical model to describe the response of NiTi rotary endodontic files in a curved root canal.

    Science.gov (United States)

    Leroy, Agnès Marie Françoise; Bahia, Maria Guiomar de Azevedo; Ehrlacher, Alain; Buono, Vicente Tadeu Lopes

    2012-08-01

    To build a mathematical model describing the mechanical behavior of NiTi rotary files while they are rotating in a root canal. The file was seen as a beam undergoing large transformations. The instrument was assumed to be rotating steadily in the root canal, and the geometry of the canal was considered as a known parameter of the problem. The formulae of large transformations mechanics then allowed the calculation of the Green-Lagrange strain field in the file. The non-linear mechanical behavior of NiTi was modeled as a continuous piecewise linear function, assuming that the material did not reach plastic deformation. Criteria locating the changes of behavior of NiTi were established and the tension field in the file, and the external efforts applied on it were calculated. The unknown variable of torsion was deduced from the equilibrium equation system using a Coulomb contact law which solved the problem on a cycle of rotation. In order to verify that the model described well reality, three-point bending experiments were managed on superelastic NiTi wires, whose results were compared to the theoretical ones. It appeared that the model gave a good mentoring of the empirical results in the range of bending angles that interested us. Knowing the geometry of the root canal, one is now able to write the equations of the strain and stress fields in the endodontic instrument, and to quantify the impact of each macroscopic parameter of the problem on its response. This should be useful to predict failure of the files under rotating bending fatigue, and to optimize the geometry of the files. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. An analytical mechanical model to describe the response of NiTi rotary endodontic files in a curved root canal

    Energy Technology Data Exchange (ETDEWEB)

    Leroy, Agnes Marie Francoise [Department of Metallurgical and Materials Engineering, School of Engineering, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Department of Mechanical and Materials Engineering, Ecole des Ponts Paristech (ENPC), Champs-sur-Marne (France); Bahia, Maria Guiomar de Azevedo [Department of Restorative Dentistry, Faculty of Dentistry, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Ehrlacher, Alain [Department of Mechanical and Materials Engineering, Ecole des Ponts Paristech (ENPC), Champs-sur-Marne (France); Buono, Vicente Tadeu Lopes, E-mail: vbuono@demet.ufmg.br [Department of Metallurgical and Materials Engineering, School of Engineering, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2012-08-01

    Aim: To build a mathematical model describing the mechanical behavior of NiTi rotary files while they are rotating in a root canal. Methodology: The file was seen as a beam undergoing large transformations. The instrument was assumed to be rotating steadily in the root canal, and the geometry of the canal was considered as a known parameter of the problem. The formulae of large transformations mechanics then allowed the calculation of the Green-Lagrange strain field in the file. The non-linear mechanical behavior of NiTi was modeled as a continuous piecewise linear function, assuming that the material did not reach plastic deformation. Criteria locating the changes of behavior of NiTi were established and the tension field in the file, and the external efforts applied on it were calculated. The unknown variable of torsion was deduced from the equilibrium equation system using a Coulomb contact law which solved the problem on a cycle of rotation. Results: In order to verify that the model described well reality, three-point bending experiments were managed on superelastic NiTi wires, whose results were compared to the theoretical ones. It appeared that the model gave a good mentoring of the empirical results in the range of bending angles that interested us. Conclusions: Knowing the geometry of the root canal, one is now able to write the equations of the strain and stress fields in the endodontic instrument, and to quantify the impact of each macroscopic parameter of the problem on its response. This should be useful to predict failure of the files under rotating bending fatigue, and to optimize the geometry of the files. - Highlights: Black-Right-Pointing-Pointer A mechanical model of the behavior of a NiTi endodontic instrument was developed. Black-Right-Pointing-Pointer The model was validated with results of three-point bending tests on NiTi wires. Black-Right-Pointing-Pointer The model is appropriate for the optimization of instruments' geometry.

  6. A two-phase model to describe the dissolution of ZrO2 by molten Zr

    International Nuclear Information System (INIS)

    Belloni, J.; Fichot, F.; Goyeau, B.; Gobin, D.; Quintard, M.

    2007-01-01

    In case of a hypothetical severe accident in a nuclear Pressurized Water Reactor (PWR), the fuel elements in the core may reach very high temperatures (more than 2000 K). UO 2 (Uranium dioxide) pellets are enclosed by a cladding mainly composed of Zircaloy (Zr). If the temperature became higher than 2100 K (melting temperature of Zr), the UO 2 pellets would be in contact with molten Zr, resulting in the dissolution and liquefaction of UO 2 at a lower temperature than its melting points (3100 K). Several experimental and numerical investigations have led to a better understanding of this phenomenon but a comprehensive and consistent modeling is still missing. The goal of this paper is to propose a two-phase macroscopic model describing the dissolution of a solid alloy by a liquid. The model is limited to binary alloys and it is applied to the particular case of the dissolution of ZrO 2 by liquid Zr, for which experimental data are available (Hofmann et al., 1999). The model was established by using a volume averaging method. Numerical simulations are compared to experimental results and show a good agreement. (authors)

  7. QSAR models for describing the toxicological effects of ILs against Staphylococcus aureus based on norm indexes.

    Science.gov (United States)

    He, Wensi; Yan, Fangyou; Jia, Qingzhu; Xia, Shuqian; Wang, Qiang

    2018-03-01

    The hazardous potential of ionic liquids (ILs) is becoming an issue of great concern due to their important role in many industrial fields as green agents. The mathematical model for the toxicological effects of ILs is useful for the risk assessment and design of environmentally benign ILs. The objective of this work is to develop QSAR models to describe the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of ILs against Staphylococcus aureus (S. aureus). A total of 169 and 101 ILs with MICs and MBCs, respectively, are used to obtain multiple linear regression models based on matrix norm indexes. The norm indexes used in this work are proposed by our research group and they are first applied to estimate the antibacterial toxicity of these ILs against S. aureus. These two models precisely and reliably calculated the IL toxicities with a square of correlation coefficient (R 2 ) of 0.919 and a standard error of estimate (SE) of 0.341 (in log unit of mM) for pMIC, and an R 2 of 0.913 and SE of 0.282 for pMBC. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Developing a dimensional model for successful cognitive and emotional aging.

    Science.gov (United States)

    Vahia, Ipsit V; Thompson, Wesley K; Depp, Colin A; Allison, Matthew; Jeste, Dilip V

    2012-04-01

    There is currently a lack of consensus on the definition of successful aging (SA) and existing implementations have omitted constructs associated with SA. We used empirical methods to develop a dimensional model of SA that incorporates a wider range of associated variables, and we examined the relationship among these components using factor analysis and Bayesian Belief Nets. We administered a successful aging questionnaire comprising several standardized measures related to SA to a sample of 1948 older women enrolled in the San Diego site of the Women's Health Initiative study. The SA-related variables we included in the model were self-rated successful aging, depression severity, physical and emotional functioning, optimism, resilience, attitude towards own aging, self-efficacy, and cognitive ability. After adjusting for age, education and income, we fitted an exploratory factor analysis model to the SA-related variables and then, in order to address relationships among these factors, we computed a Bayesian Belief Net (BBN) using rotated factor scores. The SA-related variables loaded onto five factors. Based on the loading, we labeled the factors as follows: self-rated successful aging, cognition, psychosocial protective factors, physical functioning, and emotional functioning. In the BBN, self-rated successful aging emerged as the primary downstream factor and exhibited significant partial correlations with psychosocial protective factors, physical/general status and mental/emotional status but not with cognitive ability. Our study represents a step forward in developing a dimensional model of SA. Our findings also point to a potential role for psychiatry in improving successful aging by managing depressive symptoms and developing psychosocial interventions to improve self-efficacy, resilience, and optimism.

  9. Modeling disturbance and succession in forest landscapes using LANDIS: introduction

    Science.gov (United States)

    Brian R. Sturtevant; Eric J. Gustafson; Hong S. He

    2004-01-01

    Modeling forest landscape change is challenging because it involves the interaction of a variety of factors and processes, such as climate, succession, disturbance, and management. These processes occur at various spatial and temporal scales, and the interactions can be complex on heterogeneous landscapes. Because controlled field experiments designed to investigate...

  10. The Five-Factor Model of Personality and Career Success.

    Science.gov (United States)

    Seibert, Scott E.; Kraimer, Maria L.

    2001-01-01

    Measures of career success and an inventory of the Five-Factor Model of Personality were completed by 496 workers. Extraversion was related positively to salary, promotion, and career satisfaction; neuroticism was related negatively to satisfaction. A significant negative relationship between agreeableness and salary was found for workers in…

  11. Using landscape disturbance and succession models to support forest management

    Science.gov (United States)

    Eric J. Gustafson; Brian R. Sturtevant; Anatoly S. Shvidenko; Robert M. Scheller

    2010-01-01

    Managers of forested landscapes must account for multiple, interacting ecological processes operating at broad spatial and temporal scales. These interactions can be of such complexity that predictions of future forest ecosystem states are beyond the analytical capability of the human mind. Landscape disturbance and succession models (LDSM) are predictive and...

  12. A Lotka-Volterra competition model with seasonal succession.

    Science.gov (United States)

    Hsu, Sze-Bi; Zhao, Xiao-Qiang

    2012-01-01

    A complete classification for the global dynamics of a Lotka-Volterra two species competition model with seasonal succession is obtained via the stability analysis of equilibria and the theory of monotone dynamical systems. The effects of two death rates in the bad season and the proportion of the good season on the competition outcomes are also discussed. © Springer-Verlag 2011

  13. The General Education Collaboration Model: A Model for Successful Mainstreaming.

    Science.gov (United States)

    Simpson, Richard L.; Myles, Brenda Smith

    1990-01-01

    The General Education Collaboration Model is designed to support general educators teaching mainstreamed disabled students, through collaboration with special educators. The model is based on flexible departmentalization, program ownership, identification and development of supportive attitudes, student assessment as a measure of program…

  14. Numerical Modeling Describing the Effects of Heterogeneous Distributions of Asperities on the Quasi-static Evolution of Frictional Slip

    Science.gov (United States)

    Selvadurai, P. A.; Parker, J. M.; Glaser, S. D.

    2017-12-01

    A better understanding of how slip accumulates along faults and its relation to the breakdown of shear stress is beneficial to many engineering disciplines, such as, hydraulic fracture and understanding induced seismicity (among others). Asperities forming along a preexisting fault resist the relative motion of the two sides of the interface and occur due to the interaction of the surface topographies. Here, we employ a finite element model to simulate circular partial slip asperities along a nominally flat frictional interface. Shear behavior of our partial slip asperity model closely matched the theory described by Cattaneo. The asperity model was employed to simulate a small section of an experimental fault formed between two bodies of polymethyl methacrylate, which consisted of multiple asperities whose location and sizes were directly measured using a pressure sensitive film. The quasi-static shear behavior of the interface was modeled for cyclical loading conditions, and the frictional dissipation (hysteresis) was normal stress dependent. We further our understanding by synthetically modeling lognormal size distributions of asperities that were randomly distributed in space. Synthetic distributions conserved the real contact area and aspects of the size distributions from the experimental case, allowing us to compare the constitutive behaviors based solely on spacing effects. Traction-slip behavior of the experimental interface appears to be considerably affected by spatial clustering of asperities that was not present in the randomly spaced, synthetic asperity distributions. Estimates of bulk interfacial shear stiffness were determined from the constitutive traction-slip behavior and were comparable to the theoretical estimates of multi-contact interfaces with non-interacting asperities.

  15. Indirect estimation of the Convective Lognormal Transfer function model parameters for describing solute transport in unsaturated and undisturbed soil.

    Science.gov (United States)

    Mohammadi, Mohammad Hossein; Vanclooster, Marnik

    2012-05-01

    Solute transport in partially saturated soils is largely affected by fluid velocity distribution and pore size distribution within the solute transport domain. Hence, it is possible to describe the solute transport process in terms of the pore size distribution of the soil, and indirectly in terms of the soil hydraulic properties. In this paper, we present a conceptual approach that allows predicting the parameters of the Convective Lognormal Transfer model from knowledge of soil moisture and the Soil Moisture Characteristic (SMC), parameterized by means of the closed-form model of Kosugi (1996). It is assumed that in partially saturated conditions, the air filled pore volume act as an inert solid phase, allowing the use of the Arya et al. (1999) pragmatic approach to estimate solute travel time statistics from the saturation degree and SMC parameters. The approach is evaluated using a set of partially saturated transport experiments as presented by Mohammadi and Vanclooster (2011). Experimental results showed that the mean solute travel time, μ(t), increases proportionally with the depth (travel distance) and decreases with flow rate. The variance of solute travel time σ²(t) first decreases with flow rate up to 0.4-0.6 Ks and subsequently increases. For all tested BTCs predicted solute transport with μ(t) estimated from the conceptual model performed much better as compared to predictions with μ(t) and σ²(t) estimated from calibration of solute transport at shallow soil depths. The use of μ(t) estimated from the conceptual model therefore increases the robustness of the CLT model in predicting solute transport in heterogeneous soils at larger depths. In view of the fact that reasonable indirect estimates of the SMC can be made from basic soil properties using pedotransfer functions, the presented approach may be useful for predicting solute transport at field or watershed scales. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Gaze patterns reveal how texts are remembered: A mental model of what was described is favored over the text itself

    DEFF Research Database (Denmark)

    Traub, Franziska; Johansson, Roger; Holmqvist, Kenneth

    or incongruent with the spatial layout of the text itself. 28 participants read and recalled three texts: (1) a scene description congruent with the spatial layout of the text; (2) a scene description incongruent with the spatial layout of the text; and (3) a control text without any spatial scene content....... Recollection was performed orally while gazing at a blank screen. 
Results demonstrate that participant’s gaze patterns during recall more closely reflect the spatial layout of the scene than the physical locations of the text. We conclude that participants formed a mental model that represents the content...... of what was described, i.e., visuospatial information of the scene, which then guided the retrieval process. During their retellings, they moved the eyes across the blank screen as if they saw the scene in front of them. Whereas previous studies on the involvement of eye movements in mental imagery tasks...

  17. Marquardt's Phi mask: pitfalls of relying on fashion models and the golden ratio to describe a beautiful face.

    Science.gov (United States)

    Holland, E

    2008-03-01

    Stephen Marquardt has derived a mask from the golden ratio that he claims represents the "ideal" facial archetype. Many have found his mask convincing, including cosmetic surgeons. However, Marquardt's mask is associated with numerous problems. The method used to examine goodness of fit with the proportions in the mask is faulty. The mask is ill-suited for non-European populations, especially sub-Saharan Africans and East Asians. The mask also appears to approximate the face shape of masculinized European women. Given that the general public strongly and overwhelmingly prefers above average facial femininity in women, white women seeking aesthetic facial surgery would be ill-advised to aim toward a better fit with Marquardt's mask. This article aims to show the proper way of assessing goodness of fit with Marquardt's mask, to address the shape of the mask as it pertains to masculinity-femininity, and to discuss the broader issue of an objective assessment of facial attractiveness. Generalized Procrustes analysis is used to show how goodness of fit with Marquardt's mask can be assessed. Thin-plate spline analysis is used to illustrate visually how sample faces, including northwestern European averages, differ from Marquardt's mask. Marquardt's mask best describes the facial proportions of masculinized white women as seen in fashion models. Marquardt's mask does not appear to describe "ideal" face shape even for white women because its proportions are inconsistent with the optimal preferences of most people, especially with regard to femininity.

  18. Can model Hamiltonians describe the electron–electron interaction in π-conjugated systems?: PAH and graphene

    International Nuclear Information System (INIS)

    Chiappe, G; Louis, E; San-Fabián, E; Vergés, J A

    2015-01-01

    Model Hamiltonians have been, and still are, a valuable tool for investigating the electronic structure of systems for which mean field theories work poorly. This review will concentrate on the application of Pariser–Parr–Pople (PPP) and Hubbard Hamiltonians to investigate some relevant properties of polycyclic aromatic hydrocarbons (PAH) and graphene. When presenting these two Hamiltonians we will resort to second quantisation which, although not the way chosen in its original proposal of the former, is much clearer. We will not attempt to be comprehensive, but rather our objective will be to try to provide the reader with information on what kinds of problems they will encounter and what tools they will need to solve them. One of the key issues concerning model Hamiltonians that will be treated in detail is the choice of model parameters. Although model Hamiltonians reduce the complexity of the original Hamiltonian, they cannot be solved in most cases exactly. So, we shall first consider the Hartree–Fock approximation, still the only tool for handling large systems, besides density functional theory (DFT) approaches. We proceed by discussing to what extent one may exactly solve model Hamiltonians and the Lanczos approach. We shall describe the configuration interaction (CI) method, a common technology in quantum chemistry but one rarely used to solve model Hamiltonians. In particular, we propose a variant of the Lanczos method, inspired by CI, that has the novelty of using as the seed of the Lanczos process a mean field (Hartree–Fock) determinant (the method will be named LCI). Two questions of interest related to model Hamiltonians will be discussed: (i) when including long-range interactions, how crucial is including in the Hamiltonian the electronic charge that compensates ion charges? (ii) Is it possible to reduce a Hamiltonian incorporating Coulomb interactions (PPP) to an ‘effective’ Hamiltonian including only on-site interactions (Hubbard)? The

  19. Accounting for parameter uncertainty in the definition of parametric distributions used to describe individual patient variation in health economic models

    Directory of Open Access Journals (Sweden)

    Koen Degeling

    2017-12-01

    Full Text Available Abstract Background Parametric distributions based on individual patient data can be used to represent both stochastic and parameter uncertainty. Although general guidance is available on how parameter uncertainty should be accounted for in probabilistic sensitivity analysis, there is no comprehensive guidance on reflecting parameter uncertainty in the (correlated parameters of distributions used to represent stochastic uncertainty in patient-level models. This study aims to provide this guidance by proposing appropriate methods and illustrating the impact of this uncertainty on modeling outcomes. Methods Two approaches, 1 using non-parametric bootstrapping and 2 using multivariate Normal distributions, were applied in a simulation and case study. The approaches were compared based on point-estimates and distributions of time-to-event and health economic outcomes. To assess sample size impact on the uncertainty in these outcomes, sample size was varied in the simulation study and subgroup analyses were performed for the case-study. Results Accounting for parameter uncertainty in distributions that reflect stochastic uncertainty substantially increased the uncertainty surrounding health economic outcomes, illustrated by larger confidence ellipses surrounding the cost-effectiveness point-estimates and different cost-effectiveness acceptability curves. Although both approaches performed similar for larger sample sizes (i.e. n = 500, the second approach was more sensitive to extreme values for small sample sizes (i.e. n = 25, yielding infeasible modeling outcomes. Conclusions Modelers should be aware that parameter uncertainty in distributions used to describe stochastic uncertainty needs to be reflected in probabilistic sensitivity analysis, as it could substantially impact the total amount of uncertainty surrounding health economic outcomes. If feasible, the bootstrap approach is recommended to account for this uncertainty.

  20. Accounting for parameter uncertainty in the definition of parametric distributions used to describe individual patient variation in health economic models.

    Science.gov (United States)

    Degeling, Koen; IJzerman, Maarten J; Koopman, Miriam; Koffijberg, Hendrik

    2017-12-15

    Parametric distributions based on individual patient data can be used to represent both stochastic and parameter uncertainty. Although general guidance is available on how parameter uncertainty should be accounted for in probabilistic sensitivity analysis, there is no comprehensive guidance on reflecting parameter uncertainty in the (correlated) parameters of distributions used to represent stochastic uncertainty in patient-level models. This study aims to provide this guidance by proposing appropriate methods and illustrating the impact of this uncertainty on modeling outcomes. Two approaches, 1) using non-parametric bootstrapping and 2) using multivariate Normal distributions, were applied in a simulation and case study. The approaches were compared based on point-estimates and distributions of time-to-event and health economic outcomes. To assess sample size impact on the uncertainty in these outcomes, sample size was varied in the simulation study and subgroup analyses were performed for the case-study. Accounting for parameter uncertainty in distributions that reflect stochastic uncertainty substantially increased the uncertainty surrounding health economic outcomes, illustrated by larger confidence ellipses surrounding the cost-effectiveness point-estimates and different cost-effectiveness acceptability curves. Although both approaches performed similar for larger sample sizes (i.e. n = 500), the second approach was more sensitive to extreme values for small sample sizes (i.e. n = 25), yielding infeasible modeling outcomes. Modelers should be aware that parameter uncertainty in distributions used to describe stochastic uncertainty needs to be reflected in probabilistic sensitivity analysis, as it could substantially impact the total amount of uncertainty surrounding health economic outcomes. If feasible, the bootstrap approach is recommended to account for this uncertainty.

  1. Exploring nursing e-learning systems success based on information system success model.

    Science.gov (United States)

    Chang, Hui-Chuan; Liu, Chung-Feng; Hwang, Hsin-Ginn

    2011-12-01

    E-learning is thought of as an innovative approach to enhance nurses' care service knowledge. Extensive research has provided rich information toward system development, courses design, and nurses' satisfaction with an e-learning system. However, a comprehensive view in understanding nursing e-learning system success is an important but less focused-on topic. The purpose of this research was to explore net benefits of nursing e-learning systems based on the updated DeLone and McLean's Information System Success Model. The study used a self-administered questionnaire to collected 208 valid nurses' responses from 21 of Taiwan's medium- and large-scale hospitals that have implemented nursing e-learning systems. The result confirms that the model is sufficient to explore the nurses' use of e-learning systems in terms of intention to use, user satisfaction, and net benefits. However, while the three exogenous quality factors (system quality, information quality, and service quality) were all found to be critical factors affecting user satisfaction, only information quality showed a direct effect on the intention to use. This study provides useful insights for evaluating nursing e-learning system qualities as well as an understanding of nurses' intentions and satisfaction related to performance benefits.

  2. A one-dimensional model to describe flow localization in viscoplastic slender bars subjected to super critical impact velocities

    Science.gov (United States)

    Vaz-Romero, A.; Rodríguez-Martínez, J. A.

    2018-01-01

    In this paper we investigate flow localization in viscoplastic slender bars subjected to dynamic tension. We explore loading rates above the critical impact velocity: the wave initiated in the impacted end by the applied velocity is the trigger for the localization of plastic deformation. The problem has been addressed using two kinds of numerical simulations: (1) one-dimensional finite difference calculations and (2) axisymmetric finite element computations. The latter calculations have been used to validate the capacity of the finite difference model to describe plastic flow localization at high impact velocities. The finite difference model, which highlights due to its simplicity, allows to obtain insights into the role played by the strain rate and temperature sensitivities of the material in the process of dynamic flow localization. Specifically, we have shown that viscosity can stabilize the material behavior to the point of preventing the appearance of the critical impact velocity. This is a key outcome of our investigation, which, to the best of the authors' knowledge, has not been previously reported in the literature.

  3. Application of inverse modeling technique to describe hydrogeochemical processes responsible to spatial distribution of groundwater quality along flowpath

    Directory of Open Access Journals (Sweden)

    Tjahyo NugrohoAdji

    2013-07-01

    The result shows that firstly, the aquifer within the research area can be grouped into several aquifer systems (i.e. denudational hill, colluvial plain, alluvial plain, and beach ridges from recharge to discharge which generally have potential groundwater resources in terms of the depth and fluctuation of groundwater table. Secondly, flownets analysis gives three flowpaths that are plausible to be modeled in order to describe their hydrogeochemical reactions. Thirdly, the Saturation Indices (SI analysis shows that there are a positive correlation between the mineral occurrence and composition and the value of SI from recharge to discharge. In addition, The Mass Balance Model indicates that dissolution and precipitation of aquifer minerals is dominantly change the chemical composition along flowpath and the rate of the mass transfer between two wells shows a discrepancy and be certain of the percentage of the nature of aquifer mineral. Lastly, there is an interesting characteristic of mass balance chemical reaction occurs which is the entire chemical reaction shows that the sum of smallest mineral fmmol/litre will firstly always totally be reacted.

  4. Models describing mackerel (Scomber scombrus early life growth in the North and Northwest of the Iberian Peninsula in 2000

    Directory of Open Access Journals (Sweden)

    Begoña Villamor

    2004-12-01

    Full Text Available Mackerel (Scomber scombrus in early life stages were captured in 2000 in the north and northwest of the Iberian Peninsula (ICES Divisions VIIIc and IXa North. Daily rings on their otolith sagittae were identified. Otoliths from 377 larvae and post-larvae caught in April and May 2000, ranging in length from 2.3 to 23.7 mm LS (Standard length and ranging in age from 7 to 38 days after hatching were analysed. Additionally, 68 otoliths from juveniles and pre-recruits caught between July and October 2000 with a length range of 121-202 mm LS and aged between 65-186 days after hatching were analysed. Gompertz and Logistic growth models were fitted to the pooled length at age data of the larvae-postlarvae and juveniles-pre-recruits. As length at hatch is assumed in the literature to be 3.0 mm, the models were applied in two ways; not forced to pass through L0=3.0 mm and forced to pass through L0=3.0 mm. The unforced logistic growth curve appeared to be the most suitable for describing growth during the first year of life of mackerel (L? = 191.6 mm; K= 0.070; t0= 66.7 d.

  5. An extended model based on the modified Nernst-Planck equation for describing transdermal iontophoresis of weak electrolytes.

    Science.gov (United States)

    Imanidis, Georgios; Luetolf, Peter

    2006-07-01

    An extended model for iontophoretic enhancement of transdermal drug permeation under constant voltage is described based on the previously modified Nernst-Planck equation, which included the effect of convective solvent flow. This model resulted in an analytical expression for the enhancement factor as a function of applied voltage, convective flow velocity due to electroosmosis, ratio of lipid to aqueous pathway passive permeability, and weighted average net ionic valence of the permeant in the aqueous epidermis domain. The shift of pH in the epidermis compared to bulk caused by the electrical double layer at the lipid-aqueous domain interface was evaluated using the Poisson-Boltzmann equation. This was solved numerically for representative surface charge densities and yielded pH differences between bulk and epidermal aqueous domain between 0.05 and 0.4 pH units. The developed model was used to analyze the experimental enhancement of an amphoteric weak electrolyte measured in vitro using human cadaver epidermis and a voltage of 250 mV at different pH values. Parameter values characterizing the involved factors were determined that yielded the experimental enhancement factors and passive permeability coefficients at all pH values. The model provided a very good agreement between experimental and calculated enhancement and passive permeability. The deduced parameters showed (i) that the pH shift in the aqueous permeation pathway had a notable effect on the ionic valence and the partitioning of the drug in this domain for a high surface charge density and depending on the pK(a) and pI of the drug in relation to the bulk pH; (ii) the magnitude and the direction of convective transport due to electroosmosis typically reflected the density and sign, respectively, of surface charge of the tissue and its effect on enhancement was substantial for bulk pH values differing from the pI of epidermal tissue; (iii) the aqueous pathway predominantly determined passive

  6. Development of a Predictive Model for Induction Success of Labour

    Directory of Open Access Journals (Sweden)

    Cristina Pruenza

    2018-03-01

    Full Text Available Induction of the labour process is an extraordinarily common procedure used in some pregnancies. Obstetricians face the need to end a pregnancy, for medical reasons usually (maternal or fetal requirements or less frequently, social (elective inductions for convenience. The success of induction procedure is conditioned by a multitude of maternal and fetal variables that appear before or during pregnancy or birth process, with a low predictive value. The failure of the induction process involves performing a caesarean section. This project arises from the clinical need to resolve a situation of uncertainty that occurs frequently in our clinical practice. Since the weight of clinical variables is not adequately weighted, we consider very interesting to know a priori the possibility of success of induction to dismiss those inductions with high probability of failure, avoiding unnecessary procedures or postponing end if possible. We developed a predictive model of induced labour success as a support tool in clinical decision making. Improve the predictability of a successful induction is one of the current challenges of Obstetrics because of its negative impact. The identification of those patients with high chances of failure, will allow us to offer them better care improving their health outcomes (adverse perinatal outcomes for mother and newborn, costs (medication, hospitalization, qualified staff and patient perceived quality. Therefore a Clinical Decision Support System was developed to give support to the Obstetricians. In this article, we had proposed a robust method to explore and model a source of clinical information with the purpose of obtaining all possible knowledge. Generally, in classification models are difficult to know the contribution that each attribute provides to the model. We had worked in this direction to offer transparency to models that may be considered as black boxes. The positive results obtained from both the

  7. Mechanisms for improving mass transfer in food with ultrasound technology: Describing the phenomena in two model cases.

    Science.gov (United States)

    Miano, Alberto Claudio; Ibarz, Albert; Augusto, Pedro Esteves Duarte

    2016-03-01

    The aim of this work was to demonstrate how ultrasound mechanisms (direct and indirect effects) improve the mass transfer phenomena in food processing, and which part of the process they are more effective in. Two model cases were evaluated: the hydration of sorghum grain (with two water activities) and the influx of a pigment into melon cylinders. Different treatments enabled us to evaluate and discriminate both direct (inertial flow and "sponge effect") and indirect effects (micro channel formation), alternating pre-treatments and treatments using an ultrasonic bath (20 kHz of frequency and 28 W/L of volumetric power) and a traditional water-bath. It was demonstrated that both the effects of ultrasound technology are more effective in food with higher water activity, the micro channels only forming in moist food. Moreover, micro channel formation could also be observed using agar gel cylinders, verifying the random formation of these due to cavitation. The direct effects were shown to be important in mass transfer enhancement not only in moist food, but also in dry food, this being improved by the micro channels formed and the porosity of the food. In conclusion, the improvement in mass transfer due to direct and indirect effects was firstly discriminated and described. It was proven that both phenomena are important for mass transfer in moist foods, while only the direct effects are important for dry foods. Based on these results, better processing using ultrasound technology can be obtained. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. One-dimensional Fermi accelerator model with moving wall described by a nonlinear van der Pol oscillator.

    Science.gov (United States)

    Botari, Tiago; Leonel, Edson D

    2013-01-01

    A modification of the one-dimensional Fermi accelerator model is considered in this work. The dynamics of a classical particle of mass m, confined to bounce elastically between two rigid walls where one is described by a nonlinear van der Pol type oscillator while the other one is fixed, working as a reinjection mechanism of the particle for a next collision, is carefully made by the use of a two-dimensional nonlinear mapping. Two cases are considered: (i) the situation where the particle has mass negligible as compared to the mass of the moving wall and does not affect the motion of it; and (ii) the case where collisions of the particle do affect the movement of the moving wall. For case (i) the phase space is of mixed type leading us to observe a scaling of the average velocity as a function of the parameter (χ) controlling the nonlinearity of the moving wall. For large χ, a diffusion on the velocity is observed leading to the conclusion that Fermi acceleration is taking place. On the other hand, for case (ii), the motion of the moving wall is affected by collisions with the particle. However, due to the properties of the van der Pol oscillator, the moving wall relaxes again to a limit cycle. Such kind of motion absorbs part of the energy of the particle leading to a suppression of the unlimited energy gain as observed in case (i). The phase space shows a set of attractors of different periods whose basin of attraction has a complicated organization.

  9. Stochastic GARCH dynamics describing correlations between stocks

    Science.gov (United States)

    Prat-Ortega, G.; Savel'ev, S. E.

    2014-09-01

    The ARCH and GARCH processes have been successfully used for modelling price dynamics such as stock returns or foreign exchange rates. Analysing the long range correlations between stocks, we propose a model, based on the GARCH process, which is able to describe the main characteristics of the stock price correlations, including the mean, variance, probability density distribution and the noise spectrum.

  10. Entrepreneurial Women in Radiology: Role Models of Success.

    Science.gov (United States)

    Anzai, Yoshimi; Meltzer, Carolyn C; DeStigter, Kristen K; Destounis, Stamatia; Pawley, Barbara K; Oates, M Elizabeth

    2016-11-01

    Radiology is undeniably male dominated. Alongside surgery and orthopedic surgery, academic radiology ranks near the bottom in having the lowest proportion of full-time female faculty members. Despite many efforts to recruit talented women, the pipeline entering the radiologic disciplines continues to flow at a trickle. One factor is the relative lack of role models for female medical students. Entrepreneurial women in radiology can lead the field with their innovation and creativity, courage, and commitment. In this article, the authors highlight two entrepreneurial female radiologists who shared their success stories at the American Association for Women Radiologists' session at the 2015 ACR annual meeting. Their successes underscore the potential for such women to serve as role models to female medical students and even college undergraduates. Despite the gender gap in radiology, the field has yielded some exceptional women who can take on challenges, overcome barriers and assume risks, create strategies and processes to operationalize their visions, secure funding, and expand their enterprises to make sustainable impacts both at home and abroad. As we move toward more patient- and family-centered care models and become increasingly visible to diverse populations, there is no better time for female leaders in radiology to inspire the next generation to join our essential and rewarding specialty. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  11. Successful model of suicide prevention in the Ukraine military environment.

    Science.gov (United States)

    Rozanov, Vsevolod A; Mokhovikov, Alexander N; Stiliha, Richard

    2002-01-01

    The article deals with the problem of suicidal behavior in the Ukraine military environment and gives an example of the successful prevention approach. The model of prevention is based on (1) education of the responsible officers, (2) training of the representatives of the most vulnerable risk groups, and (3) follow-up procedures based on distribution of pocket books for soldiers, educational booklets, and sets of helpful materials for officers. One of the main conclusions is that the prevention activity must be organized as a continuum of actions, seminars, consultations, and materials distribution.

  12. Item response theory and structural equation modelling for ordinal data: Describing the relationship between KIDSCREEN and Life-H.

    Science.gov (United States)

    Titman, Andrew C; Lancaster, Gillian A; Colver, Allan F

    2016-10-01

    Both item response theory and structural equation models are useful in the analysis of ordered categorical responses from health assessment questionnaires. We highlight the advantages and disadvantages of the item response theory and structural equation modelling approaches to modelling ordinal data, from within a community health setting. Using data from the SPARCLE project focussing on children with cerebral palsy, this paper investigates the relationship between two ordinal rating scales, the KIDSCREEN, which measures quality-of-life, and Life-H, which measures participation. Practical issues relating to fitting models, such as non-positive definite observed or fitted correlation matrices, and approaches to assessing model fit are discussed. item response theory models allow properties such as the conditional independence of particular domains of a measurement instrument to be assessed. When, as with the SPARCLE data, the latent traits are multidimensional, structural equation models generally provide a much more convenient modelling framework. © The Author(s) 2013.

  13. Developing entrepreneurial competencies for successful business model canvas

    Science.gov (United States)

    Sundah, D. I. E.; Langi, C.; Maramis, D. R. S.; Tawalujan, L. dan

    2018-01-01

    We explore the competencies of entrepreneurship that contribute to business model canvas. This research conducted at smoked fish industries in Province of North Sulawesi, Indonesia. This research used a mixed method which integrating both quantitative and qualitative approaches in a sequential design. The technique of snowball sampling and questionnaire has been used in collecting data from 44 entrepreneurs. Structural equation modeling with SmartPLS application program has been used in analyzing this data to determine the effect of entrepreneurial competencies on business model canvas. We also investigate 3 entrepreneurs who conducted smoked fish business and analyzed their business by using business model canvas. Focus Group Discussion is used in collecting data from 2 groups of entrepreneurs from 2 different locations. The empirical results show that entrepreneurial competencies which consists of managerial competencies, technical competencies, marketing competencies, financial competencies, human relations competencies, and the specific working attitude of entrepreneur has a positive and significantly effect on business model canvas. Additionally, the empirical cases and discussion with 2 groups of entrepreneurs support the quantitative result and it found that human relations competencies have greater influence in achieving successful business model canvas.

  14. Preparing for success: Readiness models for rural telehealth

    Directory of Open Access Journals (Sweden)

    Jennett P

    2005-01-01

    Full Text Available Background: Readiness is an integral and preliminary step in the successful implementation of telehealth services into existing health systems within rural communities. Methods and Materials: This paper details and critiques published international peer-reviewed studies that have focused on assessing telehealth readiness for rural and remote health. Background specific to readiness and change theories is provided, followed by a critique of identified telehealth readiness models, including a commentary on their readiness assessment tools. Results: Four current readiness models resulted from the search process. The four models varied across settings, such as rural outpatient practices, hospice programs, rural communities, as well as government agencies, national associations, and organizations. All models provided frameworks for readiness tools. Two specifically provided a mechanism by which communities could be categorized by their level of telehealth readiness. Discussion: Common themes across models included: an appreciation of practice context, strong leadership, and a perceived need to improve practice. Broad dissemination of these telehealth readiness models and tools is necessary to promote awareness and assessment of readiness. This will significantly aid organizations to facilitate the implementation of telehealth.

  15. Linear mixed-effects models to describe individual tree crown width for China-fir in Fujian Province, southeast China.

    Science.gov (United States)

    Hao, Xu; Yujun, Sun; Xinjie, Wang; Jin, Wang; Yao, Fu

    2015-01-01

    A multiple linear model was developed for individual tree crown width of Cunninghamia lanceolata (Lamb.) Hook in Fujian province, southeast China. Data were obtained from 55 sample plots of pure China-fir plantation stands. An Ordinary Linear Least Squares (OLS) regression was used to establish the crown width model. To adjust for correlations between observations from the same sample plots, we developed one level linear mixed-effects (LME) models based on the multiple linear model, which take into account the random effects of plots. The best random effects combinations for the LME models were determined by the Akaike's information criterion, the Bayesian information criterion and the -2logarithm likelihood. Heteroscedasticity was reduced by three residual variance functions: the power function, the exponential function and the constant plus power function. The spatial correlation was modeled by three correlation structures: the first-order autoregressive structure [AR(1)], a combination of first-order autoregressive and moving average structures [ARMA(1,1)], and the compound symmetry structure (CS). Then, the LME model was compared to the multiple linear model using the absolute mean residual (AMR), the root mean square error (RMSE), and the adjusted coefficient of determination (adj-R2). For individual tree crown width models, the one level LME model showed the best performance. An independent dataset was used to test the performance of the models and to demonstrate the advantage of calibrating LME models.

  16. Goals and Values in School: A Model Developed for Describing, Evaluating and Changing the Social Climate of Learning Environments

    Science.gov (United States)

    Allodi, Mara Westling

    2010-01-01

    This paper defines a broad model of the psychosocial climate in educational settings. The model was developed from a general theory of learning environments, on a theory of human values and on empirical studies of children's evaluations of their schools. The contents of the model are creativity, stimulation, achievement, self-efficacy, creativity,…

  17. Extension of the GroIMP modelling platform to allow easy specification of differential equations describing biological processes within plant models

    NARCIS (Netherlands)

    Hemmerling, R.; Evers, J.B.; Smolenova, K.; Buck-Sorlin, G.H.; Kurth, W.

    2013-01-01

    In simulation models of plant development, physiological processes taking place in plants are typically described in terms of ODEs (Ordinary Differential Equations). On the one hand, those processes drive the development of the plant structure and on the other hand, the developed structure again

  18. Model of succession in degraded areas based on carabid beetles (Coleoptera, Carabidae

    Directory of Open Access Journals (Sweden)

    Axel Schwerk

    2011-05-01

    Full Text Available Degraded areas constitute challenging tasks with respect to sustainable management of natural resources. Maintaining or even establishing certain successional stages seems to be particularly important. This paper presents a model of the succession in five different types of degraded areas in Poland based on changes in the carabid fauna. Mean Individual Biomass of Carabidae (MIB was used as a numerical measure for the stage of succession. The run of succession differed clearly among the different types of degraded areas. Initial conditions (origin of soil and origin of vegetation and landscape related aspects seem to be important with respect to these differences. As characteristic phases, a ‘delay phase’, an ‘increase phase’ and a ‘stagnation phase’ were identified. In general, the runs of succession could be described by four different parameters: (1 ‘Initial degradation level’, (2 ‘delay’, (3 ‘increase rate’ and (4 ‘recovery level’. Applying the analytic solution of the logistic equation, characteristic values for the parameters were identified for each of the five area types. The model is of practical use, because it provides a possibility to compare the values of the parameters elaborated in different areas, to give hints for intervention and to provide prognoses about future succession in the areas. Furthermore, it is possible to transfer the model to other indicators of succession.

  19. Model of succession in degraded areas based on carabid beetles (Coleoptera, Carabidae).

    Science.gov (United States)

    Schwerk, Axel; Szyszko, Jan

    2011-01-01

    Degraded areas constitute challenging tasks with respect to sustainable management of natural resources. Maintaining or even establishing certain successional stages seems to be particularly important. This paper presents a model of the succession in five different types of degraded areas in Poland based on changes in the carabid fauna. Mean Individual Biomass of Carabidae (MIB) was used as a numerical measure for the stage of succession. The run of succession differed clearly among the different types of degraded areas. Initial conditions (origin of soil and origin of vegetation) and landscape related aspects seem to be important with respect to these differences. As characteristic phases, a 'delay phase', an 'increase phase' and a 'stagnation phase' were identified. In general, the runs of succession could be described by four different parameters: (1) 'Initial degradation level', (2) 'delay', (3) 'increase rate' and (4) 'recovery level'. Applying the analytic solution of the logistic equation, characteristic values for the parameters were identified for each of the five area types. The model is of practical use, because it provides a possibility to compare the values of the parameters elaborated in different areas, to give hints for intervention and to provide prognoses about future succession in the areas. Furthermore, it is possible to transfer the model to other indicators of succession.

  20. Successful public-private partnerships: The NYPD shield model.

    Science.gov (United States)

    Amadeo, Vincent; Iannone, Stephen

    2017-12-01

    This article will identify the challenges that post 9/11 law enforcement faces regarding privatepublic partnerships and describe in detail the NYPD Shield programme, created to combat those challenges. Recommendations made by the 911 Commission included the incorporation of the private sector into future homeland security strategies. One such strategy is NYPD Shield. This programme is a nationally recognized award-winning public-private partnership dedicated to providing counterterrorism training and information sharing with government agencies, non-government organizations, private businesses, and the community. Information is shared through several platforms that include a dedicated website, instruction of counterterrorism training curricula, e-mail alerts, intelligence assessments and the hosting of quarterly conferences. This article also details how the NYPD Shield is providing its successful template to other law enforcement agencies enabling them to initiate similar programmes in their respective jurisdictions, and in doing so joining a National Shield Network.

  1. Development of a cloud microphysical model and parameterizations to describe the effect of CCN on warm cloud

    Directory of Open Access Journals (Sweden)

    N. Kuba

    2006-01-01

    Full Text Available First, a hybrid cloud microphysical model was developed that incorporates both Lagrangian and Eulerian frameworks to study quantitatively the effect of cloud condensation nuclei (CCN on the precipitation of warm clouds. A parcel model and a grid model comprise the cloud model. The condensation growth of CCN in each parcel is estimated in a Lagrangian framework. Changes in cloud droplet size distribution arising from condensation and coalescence are calculated on grid points using a two-moment bin method in a semi-Lagrangian framework. Sedimentation and advection are estimated in the Eulerian framework between grid points. Results from the cloud model show that an increase in the number of CCN affects both the amount and the area of precipitation. Additionally, results from the hybrid microphysical model and Kessler's parameterization were compared. Second, new parameterizations were developed that estimate the number and size distribution of cloud droplets given the updraft velocity and the number of CCN. The parameterizations were derived from the results of numerous numerical experiments that used the cloud microphysical parcel model. The input information of CCN for these parameterizations is only several values of CCN spectrum (they are given by CCN counter for example. It is more convenient than conventional parameterizations those need values concerned with CCN spectrum, C and k in the equation of N=CSk, or, breadth, total number and median radius, for example. The new parameterizations' predictions of initial cloud droplet size distribution for the bin method were verified by using the aforesaid hybrid microphysical model. The newly developed parameterizations will save computing time, and can effectively approximate components of cloud microphysics in a non-hydrostatic cloud model. The parameterizations are useful not only in the bin method in the regional cloud-resolving model but also both for a two-moment bulk microphysical model and

  2. Challenges involved in the development of models describing the running hot of engines; Herausforderungen bei der Entwicklung von Motorwarmlaufmodellen

    Energy Technology Data Exchange (ETDEWEB)

    Unterguggenberger, Peter; Salbrechter, Sebastian; Jauk, Thomas; Wimmer, Andreas [Technische Univ. Graz (Austria). Inst. fuer Verbrennungskraftmaschinen und Thermodynamik (IVT)

    2012-11-01

    Currently, all potential must be tapped in order to reach the increasingly tighter CO{sub 2} limits for vehicles. From the variety of possible options for reducing fuel consumption, the contribution of improved heat management should not be ignored since increased friction during warm-up results in greater fuel consumption. Engine warm-up models that calculate thermal behavior and fuel consumption are a relatively inexpensive alternative to empirical measures. In order to achieve satisfactory simulation results, the exact modeling of thermal behavior as well as friction conditions is necessary. This paper identifies the demands placed on the individual submodels based on the requirements for precision that thermal warm-up models must meet. Before treating the friction model it will explain the development of the heat input model in detail. In addition, it presents the test program needed to establish and validate the simulation model with the required measurement accuracy. (orig.)

  3. A unified degree day model describes survivorship of Copitarsia corruda Pogue & Simmons (Lepidoptera: Noctuidae) at different constant temperatures

    Science.gov (United States)

    N.N. G& #243; mez; R.C. Venette; J.R. Gould; D.F. Winograd

    2009-01-01

    Predictions of survivorship are critical to quantify the probability of establishment by an alien invasive species, but survival curves rarely distinguish between the effects of temperature on development versus senescence. We report chronological and physiological age-based survival curves for a potentially invasive noctuid, recently described as Copitarsia...

  4. Development of a mathematical model describing hydrolysis and co-fermentation of C6 and C5 sugars

    DEFF Research Database (Denmark)

    Morales Rodriguez, Ricardo; Gernaey, Krist; Meyer, Anne S.

    2010-01-01

    saccharification and co-fermentation (SSCF) of C6 and C5 sugars. Model construction has been carried out by combining existing mathematical models for enzymatic hydrolysis on the one hand and co-fermentation on the other hand. An inhibition of ethanol on cellulose conversion was introduced in order to increase...

  5. Analytical model to describe the thermal behavior of a heat discharge system in roofs; Modelo analitico que describe el comportamiento termico de un sistema de descarga de calor en techos

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Gomez, V.H.; Contreras-Espinosa, J.J.; Gonzalez-Ortiz, G.; Morillon-Galvez, D.; Fernandez-Zayas, J.L. [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)]. E-mail: vichugo@servidor.unam.mx; jjuancon2000@yahoo.com.mx; gilberto_gonzalez25@hotmail.com; damg@pumas.iingen.unam.mx; JFernandezZ@iingen.unam.mx

    2012-01-15

    The present study proposes an analytical model which describes the thermal behavior of a heat discharge system in roof, when the surfaces that constitute it are not translucent. Such a model derives from a thermal balance carried out to a heat discharge system in roofs. To validate it, an experimental prototype that allows simulating the thermal behavior of a heat discharge system in wall and roof was used, and the results were compared to those obtained with the proposed analytical model. It was found that the thermal behavior of the analytical model is similar to the thermal behavior of the experimental prototype; a worthless variation was detected among their respective outcome (The difference of temperatures can be caused by the heat transfer coefficient, of which no studies defining its behavior accurately have been found). Therefore, it can be considered that the proposed analytical model can be employed to simulate the thermal behavior of a heat discharge system in roofs when the surfaces that constitute it are opaque. [Spanish] En el presente estudio se propone un modelo analitico que describe el comportamiento termico de un sistema de descarga de calor en techo, cuando las superficies que lo componen no son translucidos. Dicho modelo surge a partir de un balance termico realizado a un sistema de descarga de calor en techos. Para validarlo, se realizaron dos corridas experimentales en un prototipo que permite simular el comportamiento termico de un sistema de descarga de calor en techo y se compararon los resultados medidos con los calculados por el modelo analitico propuesto. Se encontro que, el comportamiento termico del modelo analitico es similar al comportamiento termico del prototipo experimental, se detecto una variacion despreciable entre los valores arrojados por ambos modelos (la diferencia de temperaturas puede estar ocasionada por la obtencion del coeficiente convectivo de transferencia de calor, del cual no se han encontrado estudios que

  6. BLOW-3A. A theoretical model to describe transient two-phase flow conditions in LMFBR coolant channels

    International Nuclear Information System (INIS)

    Bottoni, M.; Struwe, D.

    1982-12-01

    The computer programme BLOW-3A describes sodium boiling phenomena in subassemblies of fast breeder reactors as well as in in-pile or out-of-pile experiments simulating different failure conditions. This report presents a complete documentation of the code from three main viewpoints: the theoretical foundations of the programme are first described with particular reference to the most recent developments; the structure of the programme is then explained in all details necessary for the user to get a rapid acquaintance with it; eventually several examples of the programme validation are discussed thus enabling the reader to acquire a full picture of the possible applications of the code and at the same time to know its validity range. (orig.) [de

  7. The Atkinson-Shiffrin model is ill-defined and does not correctly describe the Murdock free recall data

    OpenAIRE

    Tarnow, Dr. Eugen

    2009-01-01

    The Atkinson-Shiffrin (1968) model, the de facto standard model of short term memory cited thousands of times, fits the characteristically bowed free recall curves from Murdock (1962) well. However, it is long overdue to note that it is not a theoretically convincing explanation and that it does not fit all of the experimental relationships in the Murdock data. To obtain a qualitatively correct fit of the bowing I show that four model concepts have to work together. “Long term memory” is ...

  8. A Monte Carlo-adjusted goodness-of-fit test for parametric models describing spatial point patterns

    KAUST Repository

    Dao, Ngocanh; Genton, Marc G.

    2014-01-01

    Assessing the goodness-of-fit (GOF) for intricate parametric spatial point process models is important for many application fields. When the probability density of the statistic of the GOF test is intractable, a commonly used procedure is the Monte

  9. Study of market model describing the contrary behaviors of informed and uninformed agents: Being minority and being majority

    Science.gov (United States)

    Zhang, Yu-Xia; Liao, Hao; Medo, Matus; Shang, Ming-Sheng; Yeung, Chi Ho

    2016-05-01

    In this paper we analyze the contrary behaviors of the informed investors and uniformed investors, and then construct a competition model with two groups of agents, namely agents who intend to stay in minority and those who intend to stay in majority. We find two kinds of competitions, inter- and intra-groups. The model shows periodic fluctuation feature. The average distribution of strategies illustrates a prominent central peak which is relevant to the peak-fat-tail character of price change distribution in stock markets. Furthermore, in the modified model the tolerance time parameter makes the agents diversified. Finally, we compare the strategies distribution with the price change distribution in real stock market, and we conclude that contrary behavior rules and tolerance time parameter are indeed valid in the description of market model.

  10. MODEL OF SUCCESSFUL STRATEGY EXECUTION: REVISING THE CONCEPT

    Directory of Open Access Journals (Sweden)

    Joanna Radomska

    2014-12-01

    Full Text Available The purpose of this research is to examine the relationship between the elements of the Eight "S" model that affect strategic implementation and results achieved by companies. The main research question, to which the author sought an answer, was whether there was a relationship between individual elements that affect strategy implementation and the effects it brings in revenue growth. The survey covered 200 of the best-ranked Polish companies (where revenues constituted one of the ranking criteria where the level of strategic implementation was considered satisfactory. Testing of the research hypotheses has shown that the factors defined as Resources and Shared Values have a minor impact on the strategy implementation. The research also has shown that there is an additional element that could be incorporated into the model - the system of informal communication. In addition, the paper describes the interrelations between elements of the model.

  11. The inverse Gamma process: A family of continuous stochastic models for describing state-dependent deterioration phenomena

    International Nuclear Information System (INIS)

    Guida, M.; Pulcini, G.

    2013-01-01

    This paper proposes the family of non-stationary inverse Gamma processes for modeling state-dependent deterioration processes with nonlinear trend. The proposed family of processes, which is based on the assumption that the “inverse” time process is Gamma, is mathematically more tractable than previously proposed state-dependent processes, because, unlike the previous models, the inverse Gamma process is a time-continuous and state-continuous model and does not require discretization of time and state. The conditional distribution of the deterioration growth over a generic time interval, the conditional distribution of the residual life and the residual reliability of the unit, given the current state, are provided. Point and interval estimation of the parameters which index the proposed process, as well as of several quantities of interest, are also discussed. Finally, the proposed model is applied to the wear process of the liners of some Diesel engines which was previously analyzed and proved to be a purely state-dependent process. The comparison of the inferential results obtained under the competitor models shows the ability of the Inverse Gamma process to adequately model the observed state-dependent wear process

  12. A model for describing the eutrophication in a heavily regulated coastal lagoon. Application to the Albufera of Valencia (Spain).

    Science.gov (United States)

    del Barrio Fernández, Pilar; Gómez, Andrés García; Alba, Javier García; Díaz, César Álvarez; Revilla Cortezón, José Antonio

    2012-12-15

    A simplified two-dimensional eutrophication model was developed to simulate temporal and spatial variations of chlorophyll-a in heavily regulated coastal lagoons. This model considers the hydrodynamics of the whole study area, the regulated connexion of the lagoon with the sea, the variability of the input and output nutrient loads, the flux from the sediments to the water column, the phytoplankton growth and mortality kinetics, and the zooplankton grazing. The model was calibrated and validated by applying it to the Albufera of Valencia, a hypertrophic system whose connection to the sea is strongly regulated by a system of sluice-gates. The calibration and validation results presented a significant agreement between the model and the data obtained in several surveys. The accuracy was evaluated using a quantitative analysis, in which the average uncertainty of the model prediction was less than 6%. The results confirmed an expected phytoplankton bloom in April and October, achieving mean maximum values around 250 μg l(-1) of chlorophyll-a. A mass balance revealed that the eutrophication process is magnified by the input loads of nutrients, mainly from the sediments, as well as by the limited connection of the lagoon with the sea. This study has shown that the developed model is an efficient tool to manage the eutrophication problem in heavily regulated coastal lagoons. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Amicus Plato, sed magis amica veritas: plots must obey the laws they refer to and models shall describe biophysical reality!

    Science.gov (United States)

    Katkov, Igor I

    2011-06-01

    In the companion paper, we discussed in details proper linearization, calculation of the inactive osmotic volume, and analysis of the results on the Boyle-vant' Hoff plots. In this Letter, we briefly address some common errors and misconceptions in osmotic modeling and propose some approaches, namely: (1) inapplicability of the Kedem-Katchalsky formalism model in regards to the cryobiophysical reality, (2) calculation of the membrane hydraulic conductivity L(p) in the presence of permeable solutes, (3) proper linearization of the Arrhenius plots for the solute membrane permeability, (4) erroneous use of the term "toxicity" for the cryoprotective agents, and (5) advantages of the relativistic permeability approach (RP) developed by us vs. traditional ("classic") 2-parameter model. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. On one peculiarity of the model describing the interaction of the electron beam with the semiconductor surface

    Science.gov (United States)

    Stepovich, M. A.; Amrastanov, A. N.; Seregina, E. V.; Filippov, M. N.

    2018-01-01

    The problem of heat distribution in semiconductor materials irradiated with sharply focused electron beams in the absence of heat exchange between the target and the external medium is considered by mathematical modeling methods. For a quantitative description of energy losses by probe electrons a model based on a separate description of the contributions of absorbed in the target and backscattered electrons and applicable to a wide class of solids and a range of primary electron energies is used. Using the features of this approach, the nonmonotonic dependence of the temperature of the maximum heating in the target on the energy of the primary electrons is explained. Some modeling results are illustrated for semiconductor materials of electronic engineering.

  15. A physics-based crystallographic modeling framework for describing the thermal creep behavior of Fe-Cr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Wei [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Capolungo, Laurent [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Patra, Anirban [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tome, Carlos [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-02

    This Report addresses the Milestone M2MS-16LA0501032 of NEAMS Program (“Develop hardening model for FeCrAl cladding), with a deadline of 09/30/2016. Here we report a constitutive law for thermal creep of FeCrAl. This Report adds to and complements the one for Milestone M3MS-16LA0501034 (“Interface hardening models with MOOSE-BISON”), where we presented a hardening law for irradiated FeCrAl. The last component of our polycrystal-based constitutive behavior, namely, an irradiation creep model for FeCrAl, will be developed as part of the FY17 Milestones, and the three regimes will be coupled and interfaced with MOOSE-BISON.

  16. New models for success emerge for US natural gas industry

    International Nuclear Information System (INIS)

    Addy, W.M.; Hutchinson, R.A.

    1994-01-01

    Very few companies in the US natural gas industry are confident in their ability to compete effectively in the brave new world of deregulation. Boston Consulting Group recently conducted an internal study to help the industry think about its future and identify models for success in this new environment. The authors examined the historical performance of 800 companies using several shareholder-value indicators, including cash-flow returns on investment, a measure of cash returns on cash invested that correlates closely to share price. Based on that review and discussions with investment managers and industry analysts, the authors were able to focus on a handful of companies that actually have thrived and created value against the difficult landscape of the past decade. Interviews with their senior executives provided important strategic and operational insights

  17. Evaluation of a cross contamination model describing transfer of Salmonella spp. and Listeria monocytogenes during grinding of pork and beef

    DEFF Research Database (Denmark)

    Møller, Cleide Oliveira de Almeida; Sant'Ana, A.S.; Hansen, Solvej Katrine Holm

    2016-01-01

    A cross contamination model was challenged and evaluated applying a new approach.•QMRA and Total Transfer Potential (TTP) were included.•Transfer estimates were not applicable for unlike processing.•The risk of disease may be reduced when using a stainless steel grinder.•Well-sharpened knife, and...

  18. A Strategy for Describing the Biosphere at Candidate Sites for Repositories of Nuclear Waste: Linking Ecosystem and Landscape Modeling

    International Nuclear Information System (INIS)

    Lindborg, Tobias; Loefgren, Anders; Soederbaeck, Bjoern; Kautsky, Ulrik; Lindborg, Regina; Bradshaw, Clare

    2006-01-01

    To provide information necessary for a license application for a deep repository for spent nuclear fuel, the Swedish Nuclear Fuel and Waste Management Co. has started site investigations at two sites in Sweden. In this paper, we present a strategy to integrate site-specific ecosystem data into spatially explicit models needed for safety assessment studies and the environmental impact assessment. The site-specific description of ecosystems is developed by building discipline-specific models from primary data and by identifying interactions and stocks and flows of matter among functional units at the sites. The conceptual model is a helpful initial tool for defining properties needed to quantify system processes, which may reveal new interfaces between disciplines, providing a variety of new opportunities to enhance the understanding of the linkages between ecosystem characteristics and the functional properties of landscapes. This type of integrated ecosystem-landscape characterization model has an important role in forming the implementation of a safety assessment for a deep repository

  19. Application of the NDHA model to describe N2O dynamics in activated sludge mixed culture biomass

    DEFF Research Database (Denmark)

    Domingo-Felez, Carlos; Smets, Barth F.

    A pseudo-mechanistic model describing three biological nitric oxide (NO) and nitrous oxide (N2O) production pathways was calibrated for an activated sludge mixed culture biomass treating municipal wastewater with laboratory-scale experiments. The model (NDHA) comprehensively describes N2O produci...

  20. Performance of flash profile and napping with and without training for describing small sensory differences in a model wine

    DEFF Research Database (Denmark)

    Liu, Jing; Grønbeck, Marlene Schou; Di Monaco, Rosella

    2016-01-01

    . In this study different variations of two rapid sensory methods, one based on holistic assessment – Napping, and one based on attribute evaluation – Flash Profile, were tested for the evaluation of the flavour in wine. Model wines were developed with control over the sensory differences in terms of sensory...... to arrange samples on the sheet) or the product (familiarisation with the sensory properties of the wines) improved the outcome compared to the classical Napping protocol. The classical Flash Profile protocol and its modified version including a Napping with subsequent attributes generation as the word...... generation step and limiting the number of attributes for ranking gave a similar sample space. The Napping method could best highlight qualitative sample differences, whereas the Flash Profile provided a more precise product mapping on quantitative differences between model wines....

  1. Accounting for parameter uncertainty in the definition of parametric distributions used to describe individual patient variation in health economic models

    OpenAIRE

    Degeling, Koen; IJzerman, Maarten J.; Koopman, Miriam; Koffijberg, Hendrik

    2017-01-01

    Background Parametric distributions based on individual patient data can be used to represent both stochastic and parameter uncertainty. Although general guidance is available on how parameter uncertainty should be accounted for in probabilistic sensitivity analysis, there is no comprehensive guidance on reflecting parameter uncertainty in the (correlated) parameters of distributions used to represent stochastic uncertainty in patient-level models. This study aims to provide this guidance by ...

  2. A Simple Model to Describe the Relationship among Rainfall, Groundwater and Land Subsidence under a Heterogeneous Aquifer

    Science.gov (United States)

    Zheng, Y. Y.; Chen, Y. L.; Lin, H. R.; Huang, S. Y.; Yeh, T. C. J.; Wen, J. C.

    2017-12-01

    Land subsidence is a very serious problem of Zhuoshui River alluvial fan, Taiwan. The main reason of land subsidence is a compression of soil, but the compression measured in the wide area is very extensive (Maryam et al., 2013; Linlin et al., 2014). Chen et al. [2010] studied the linear relationship between groundwater level and subsurface altitude variations from Global Positioning System (GPS) station in Zhuoshui River alluvial fan. But the subsurface altitude data were only from two GPS stations. Their distributions are spared and small, not enough to express the altitude variations of Zhuoshui River alluvial fan. Hung et al. [2011] used Interferometry Synthetic Aperture Radar (InSAR) to measure the surface subsidence in Zhuoshui River alluvial fan, but haven't compared with groundwater level. The study compares the correlation between rainfall events and groundwater level and compares the correlation between groundwater level and subsurface altitude, these two correlation affected by heterogeneous soil. From these relationships, a numerical model is built to simulate the land subsidence variations and estimate the coefficient of aquifer soil compressibility. Finally, the model can estimate the long-term land subsidence. Keywords: Land Subsidence, InSAR, Groundwater Level, Numerical Model, Correlation Analyses

  3. Chemical reaction networks as a model to describe UVC- and radiolytically-induced reactions of simple compounds.

    Science.gov (United States)

    Dondi, Daniele; Merli, Daniele; Albini, Angelo; Zeffiro, Alberto; Serpone, Nick

    2012-05-01

    When a chemical system is submitted to high energy sources (UV, ionizing radiation, plasma sparks, etc.), as is expected to be the case of prebiotic chemistry studies, a plethora of reactive intermediates could form. If oxygen is present in excess, carbon dioxide and water are the major products. More interesting is the case of reducing conditions where synthetic pathways are also possible. This article examines the theoretical modeling of such systems with random-generated chemical networks. Four types of random-generated chemical networks were considered that originated from a combination of two connection topologies (viz., Poisson and scale-free) with reversible and irreversible chemical reactions. The results were analyzed taking into account the number of the most abundant products required for reaching 50% of the total number of moles of compounds at equilibrium, as this may be related to an actual problem of complex mixture analysis. The model accounts for multi-component reaction systems with no a priori knowledge of reacting species and the intermediates involved if system components are sufficiently interconnected. The approach taken is relevant to an earlier study on reactions that may have occurred in prebiotic systems where only a few compounds were detected. A validation of the model was attained on the basis of results of UVC and radiolytic reactions of prebiotic mixtures of low molecular weight compounds likely present on the primeval Earth.

  4. Capitalizing on Citizen Science Data for Validating Models and Generating Hypotheses Describing Meteorological Drivers of Mosquito-Borne Disease Risk

    Science.gov (United States)

    Boger, R. A.; Low, R.; Paull, S.; Anyamba, A.; Soebiyanto, R. P.

    2017-12-01

    Temperature and precipitation are important drivers of mosquito population dynamics, and a growing set of models have been proposed to characterize these relationships. Validation of these models, and development of broader theories across mosquito species and regions could nonetheless be improved by comparing observations from a global dataset of mosquito larvae with satellite-based measurements of meteorological variables. Citizen science data can be particularly useful for two such aspects of research into the meteorological drivers of mosquito populations: i) Broad-scale validation of mosquito distribution models and ii) Generation of quantitative hypotheses regarding changes to mosquito abundance and phenology across scales. The recently released GLOBE Observer Mosquito Habitat Mapper (GO-MHM) app engages citizen scientists in identifying vector taxa, mapping breeding sites and decommissioning non-natural habitats, and provides a potentially useful new tool for validating mosquito ubiquity projections based on the analysis of remotely sensed environmental data. Our early work with GO-MHM data focuses on two objectives: validating citizen science reports of Aedes aegypti distribution through comparison with accepted scientific data sources, and exploring the relationship between extreme temperature and precipitation events and subsequent observations of mosquito larvae. Ultimately the goal is to develop testable hypotheses regarding the shape and character of this relationship between mosquito species and regions.

  5. How Mathematics Describes Life

    Science.gov (United States)

    Teklu, Abraham

    2017-01-01

    The circle of life is something we have all heard of from somewhere, but we don't usually try to calculate it. For some time we have been working on analyzing a predator-prey model to better understand how mathematics can describe life, in particular the interaction between two different species. The model we are analyzing is called the Holling-Tanner model, and it cannot be solved analytically. The Holling-Tanner model is a very common model in population dynamics because it is a simple descriptor of how predators and prey interact. The model is a system of two differential equations. The model is not specific to any particular set of species and so it can describe predator-prey species ranging from lions and zebras to white blood cells and infections. One thing all these systems have in common are critical points. A critical point is a value for both populations that keeps both populations constant. It is important because at this point the differential equations are equal to zero. For this model there are two critical points, a predator free critical point and a coexistence critical point. Most of the analysis we did is on the coexistence critical point because the predator free critical point is always unstable and frankly less interesting than the coexistence critical point. What we did is consider two regimes for the differential equations, large B and small B. B, A, and C are parameters in the differential equations that control the system where B measures how responsive the predators are to change in the population, A represents predation of the prey, and C represents the satiation point of the prey population. For the large B case we were able to approximate the system of differential equations by a single scalar equation. For the small B case we were able to predict the limit cycle. The limit cycle is a process of the predator and prey populations growing and shrinking periodically. This model has a limit cycle in the regime of small B, that we solved for

  6. Modelling of turbulent hydrocarbon combustion. Test of different reactor concepts for describing the interactions between turbulence and chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, C; Kremer, H [Ruhr-Universitaet Bochum, Lehrstuhl fuer Energieanlagentechnik, Bochum (Germany); Kilpinen, P; Hupa, M [Aabo Akademi, Turku (Finland). Combustion Chemistry Research Group

    1998-12-31

    The detailed modelling of turbulent reactive flows with CFD-codes is a major challenge in combustion science. One method of combining highly developed turbulence models and detailed chemistry in CFD-codes is the application of reactor based turbulence chemistry interaction models. In this work the influence of different reactor concepts on methane and NO{sub x} chemistry in turbulent reactive flows was investigated. Besides the classical reactor approaches, a plug flow reactor (PFR) and a perfectly stirred reactor (PSR), the Eddy-Dissipation Combustion Model (EDX) and the Eddy Dissipation Concept (EDC) were included. Based on a detailed reaction scheme and a simplified 2-step mechanism studies were performed in a simplified computational grid consisting of 5 cells. The investigations cover a temperature range from 1273 K to 1673 K and consider fuel-rich and fuel-lean gas mixtures as well as turbulent and highly turbulent flow conditions. All test cases investigated in this study showed a strong influence of the reactor residence time on the species conversion processes. Due to this characteristic strong deviations were found for the species trends resulting from the different reactor approaches. However, this influence was only concentrated on the `near burner region` and after 4-5 cells hardly any deviation and residence time dependence could be found. The importance of the residence time dependence increased when the species conversion was accelerated as it is the case for overstoichiometric combustion conditions and increased temperatures. The study focused furthermore on the fine structure in the EDC. Unlike the classical approach this part of the cell was modelled as a PFR instead of a PSR. For high temperature conditions there was hardly any difference between both reactor types. However, decreasing the temperature led to obvious deviations. Finally, the effect of the selective species transport between the cells on the conversion process was investigated

  7. Incorporating NDVI in a gravity model setting to describe spatio-temporal patterns of Lyme borreliosis incidence

    Science.gov (United States)

    Barrios, J. M.; Verstraeten, W. W.; Farifteh, J.; Maes, P.; Aerts, J. M.; Coppin, P.

    2012-04-01

    Lyme borreliosis (LB) is the most common tick-borne disease in Europe and incidence growth has been reported in several European countries during the last decade. LB is caused by the bacterium Borrelia burgdorferi and the main vector of this pathogen in Europe is the tick Ixodes ricinus. LB incidence and spatial spread is greatly dependent on environmental conditions impacting habitat, demography and trophic interactions of ticks and the wide range of organisms ticks parasite. The landscape configuration is also a major determinant of tick habitat conditions and -very important- of the fashion and intensity of human interaction with vegetated areas, i.e. human exposure to the pathogen. Hence, spatial notions as distance and adjacency between urban and vegetated environments are related to human exposure to tick bites and, thus, to risk. This work tested the adequacy of a gravity model setting to model the observed spatio-temporal pattern of LB as a function of location and size of urban and vegetated areas and the seasonal and annual change in the vegetation dynamics as expressed by MODIS NDVI. Opting for this approach implies an analogy with Newton's law of universal gravitation in which the attraction forces between two bodies are directly proportional to the bodies mass and inversely proportional to distance. Similar implementations have proven useful in fields like trade modeling, health care service planning, disease mapping among other. In our implementation, the size of human settlements and vegetated systems and the distance separating these landscape elements are considered the 'bodies'; and the 'attraction' between them is an indicator of exposure to pathogen. A novel element of this implementation is the incorporation of NDVI to account for the seasonal and annual variation in risk. The importance of incorporating this indicator of vegetation activity resides in the fact that alterations of LB incidence pattern observed the last decade have been ascribed

  8. Modelling of turbulent hydrocarbon combustion. Test of different reactor concepts for describing the interactions between turbulence and chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, C.; Kremer, H. [Ruhr-Universitaet Bochum, Lehrstuhl fuer Energieanlagentechnik, Bochum (Germany); Kilpinen, P.; Hupa, M. [Aabo Akademi, Turku (Finland). Combustion Chemistry Research Group

    1997-12-31

    The detailed modelling of turbulent reactive flows with CFD-codes is a major challenge in combustion science. One method of combining highly developed turbulence models and detailed chemistry in CFD-codes is the application of reactor based turbulence chemistry interaction models. In this work the influence of different reactor concepts on methane and NO{sub x} chemistry in turbulent reactive flows was investigated. Besides the classical reactor approaches, a plug flow reactor (PFR) and a perfectly stirred reactor (PSR), the Eddy-Dissipation Combustion Model (EDX) and the Eddy Dissipation Concept (EDC) were included. Based on a detailed reaction scheme and a simplified 2-step mechanism studies were performed in a simplified computational grid consisting of 5 cells. The investigations cover a temperature range from 1273 K to 1673 K and consider fuel-rich and fuel-lean gas mixtures as well as turbulent and highly turbulent flow conditions. All test cases investigated in this study showed a strong influence of the reactor residence time on the species conversion processes. Due to this characteristic strong deviations were found for the species trends resulting from the different reactor approaches. However, this influence was only concentrated on the `near burner region` and after 4-5 cells hardly any deviation and residence time dependence could be found. The importance of the residence time dependence increased when the species conversion was accelerated as it is the case for overstoichiometric combustion conditions and increased temperatures. The study focused furthermore on the fine structure in the EDC. Unlike the classical approach this part of the cell was modelled as a PFR instead of a PSR. For high temperature conditions there was hardly any difference between both reactor types. However, decreasing the temperature led to obvious deviations. Finally, the effect of the selective species transport between the cells on the conversion process was investigated

  9. A Monte Carlo-adjusted goodness-of-fit test for parametric models describing spatial point patterns

    KAUST Repository

    Dao, Ngocanh

    2014-04-03

    Assessing the goodness-of-fit (GOF) for intricate parametric spatial point process models is important for many application fields. When the probability density of the statistic of the GOF test is intractable, a commonly used procedure is the Monte Carlo GOF test. Additionally, if the data comprise a single dataset, a popular version of the test plugs a parameter estimate in the hypothesized parametric model to generate data for theMonte Carlo GOF test. In this case, the test is invalid because the resulting empirical level does not reach the nominal level. In this article, we propose a method consisting of nested Monte Carlo simulations which has the following advantages: the bias of the resulting empirical level of the test is eliminated, hence the empirical levels can always reach the nominal level, and information about inhomogeneity of the data can be provided.We theoretically justify our testing procedure using Taylor expansions and demonstrate that it is correctly sized through various simulation studies. In our first data application, we discover, in agreement with Illian et al., that Phlebocarya filifolia plants near Perth, Australia, can follow a homogeneous Poisson clustered process that provides insight into the propagation mechanism of these plants. In our second data application, we find, in contrast to Diggle, that a pairwise interaction model provides a good fit to the micro-anatomy data of amacrine cells designed for analyzing the developmental growth of immature retina cells in rabbits. This article has supplementary material online. © 2013 American Statistical Association, Institute of Mathematical Statistics, and Interface Foundation of North America.

  10. A simple model describing the nonlinear dynamics of the dusk/dawn asymmetry in the high-latitude thermospheric flow

    Science.gov (United States)

    Gundlach, J. P.; Larsen, M. F.; Mikkelsen, I. S.

    1988-01-01

    A simple nonlinear, axisymmetric, shallow-water numerical model has been used to study the asymmetry in the neutral flow between the dusk and dawn sides of the auroral oval. The results indicate that the Coriolis force and the curvature terms are nearly in balance on the evening side and require only a small pressure gradient to effect adjustment. The result is smaller neutral velocities near dawn and larger velocities near dusk than would be the case for a linearized treatment. A consequence is that more gravity wave energy is produced on the morning side than on the evening side.

  11. A multi-physics modelling framework to describe the behaviour of nano-scale multilayer systems undergoing irradiation damage

    International Nuclear Information System (INIS)

    Villani, Aurelien

    2015-01-01

    Radiation damage is known to lead to material failure and thus is of critical importance to lifetime and safety within nuclear reactors. While mechanical behaviour of materials under irradiation has been the subject of numerous studies, the current predictive capabilities of such phenomena appear limited. The clustering of point defects such as vacancies and self interstitial atoms gives rise to creep, void swelling and material embrittlement. Nano-scale metallic multilayer systems have be shown to have the ability to evacuate such point defects, hence delaying the occurrence of critical damage. In addition, they exhibit outstanding mechanical properties. The objective of this work is to develop a thermodynamically consistent continuum framework at the meso and nano-scales, which accounts for the major physical processes encountered in such metallic multilayer systems and is able to predict their microstructural evolution and behavior under irradiation. Mainly three physical phenomena are addressed in the present work: stress-diffusion coupling and diffusion induced creep, the void nucleation and growth in multilayer systems under irradiation, and the interaction of dislocations with the multilayer interfaces. In this framework, the microstructure is explicitly modeled, in order to account accurately for their effects on the system behavior. The diffusion creep strain rate is related to the gradient of the vacancy flux. A Cahn-Hilliard approach is used to model void nucleation and growth, and the diffusion equations for vacancies and self interstitial atoms are complemented to take into account the production of point defects due to irradiation cascades, the mutual recombination of defects and their evacuation through grain boundaries. In metallic multilayers, an interface affected zone is defined, with an additional slip plane to model the interface shearable character, and where dislocations cores are able to spread. The model is then implemented numerically

  12. PFLOTRAN User Manual: A Massively Parallel Reactive Flow and Transport Model for Describing Surface and Subsurface Processes

    Energy Technology Data Exchange (ETDEWEB)

    Lichtner, Peter C. [OFM Research, Redmond, WA (United States); Hammond, Glenn E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lu, Chuan [Idaho National Lab. (INL), Idaho Falls, ID (United States); Karra, Satish [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bisht, Gautam [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Andre, Benjamin [National Center for Atmospheric Research, Boulder, CO (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mills, Richard [Intel Corporation, Portland, OR (United States); Univ. of Tennessee, Knoxville, TN (United States); Kumar, Jitendra [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-01-20

    PFLOTRAN solves a system of generally nonlinear partial differential equations describing multi-phase, multicomponent and multiscale reactive flow and transport in porous materials. The code is designed to run on massively parallel computing architectures as well as workstations and laptops (e.g. Hammond et al., 2011). Parallelization is achieved through domain decomposition using the PETSc (Portable Extensible Toolkit for Scientific Computation) libraries for the parallelization framework (Balay et al., 1997). PFLOTRAN has been developed from the ground up for parallel scalability and has been run on up to 218 processor cores with problem sizes up to 2 billion degrees of freedom. Written in object oriented Fortran 90, the code requires the latest compilers compatible with Fortran 2003. At the time of this writing this requires gcc 4.7.x, Intel 12.1.x and PGC compilers. As a requirement of running problems with a large number of degrees of freedom, PFLOTRAN allows reading input data that is too large to fit into memory allotted to a single processor core. The current limitation to the problem size PFLOTRAN can handle is the limitation of the HDF5 file format used for parallel IO to 32 bit integers. Noting that 232 = 4; 294; 967; 296, this gives an estimate of the maximum problem size that can be currently run with PFLOTRAN. Hopefully this limitation will be remedied in the near future.

  13. A new multiscale model to describe a modified Hall-Petch relation at different scales for nano and micro materials

    Science.gov (United States)

    Fadhil, Sadeem Abbas; Alrawi, Aoday Hashim; Azeez, Jazeel H.; Hassan, Mohsen A.

    2018-04-01

    In the present work, a multiscale model is presented and used to modify the Hall-Petch relation for different scales from nano to micro. The modified Hall-Petch relation is derived from a multiscale equation that determines the cohesive energy between the atoms and their neighboring grains. This brings with it a new term that was originally ignored even in the atomistic models. The new term makes it easy to combine all other effects to derive one modified equation for the Hall-Petch relation that works for all scales together, without the need to divide the scales into two scales, each scale with a different equation, as it is usually done in other works. Due to that, applying the new relation does not require a previous knowledge of the grain size distribution. This makes the new derived relation more consistent and easier to be applied for all scales. The new relation is used to fit the data for Copper and Nickel and it is applied well for the whole range of grain sizes from nano to micro scales.

  14. Improved rigorous upper bounds for transport due to passive advection described by simple models of bounded systems

    International Nuclear Information System (INIS)

    Kim, Chang-Bae; Krommes, J.A.

    1988-08-01

    The work of Krommes and Smith on rigorous upper bounds for the turbulent transport of a passively advected scalar [/ital Ann. Phys./ 177:246 (1987)] is extended in two directions: (1) For their ''reference model,'' improved upper bounds are obtained by utilizing more sophisticated two-time constraints which include the effects of cross-correlations up to fourth order. Numerical solutions of the model stochastic differential equation are also obtained; they show that the new bounds compare quite favorably with the exact results, even at large Reynolds and Kubo numbers. (2) The theory is extended to take account of a finite spatial autocorrelation length L/sub c/. As a reasonably generic example, the problem of particle transport due to statistically specified stochastic magnetic fields in a collisionless turbulent plasma is revisited. A bound is obtained which reduces for small L/sub c/ to the quasilinear limit and for large L/sub c/ to the strong turbulence limit, and which provides a reasonable and rigorous interpolation for intermediate values of L/sub c/. 18 refs., 6 figs

  15. Business Models for Successfully Maintaining Games for Health.

    Science.gov (United States)

    Baranowski, Moderator Tom; Isaac, Participants Fikry; Ashford, Chris; Goldman, Ron; Lenihan, David J; Poole, Brent; Buday, Richard; van Rijswijk, Jurriaan

    2013-04-01

    Videogames for health provide innovative, exciting, and possibly highly effective new media for helping players change their behaviors or otherwise benefit their health. Getting the right videogames into the hands of players who can benefit most in a way that pays for the continued innovation and creation of such games is a current challenge. Entertainment videogame companies, which create games primarily to enhance players' enjoyment, have used the general business marketplace (e.g., online stores, walk-in stores, app stores) to deliver their products directly to consumers and earn enough capital to invest in making new products. No one believes, however, that enough kids or adults would use the general business marketplace to purchase games for health in sufficient volume to provide the down payment for the innovation and creation of new games for health. A successful business model is critical to the financial future of games for health. We asked members of our Editorial Board who are in health-related companies (Fikry Isaac, MD, MPH), in several game development companies (Chris Ashford, Ron Goldman, David J. Lenihan, Brent Poole, and Richard Buday, FAIA), and the head of the Games for Health Europe Foundation (Jurriaan van Rijswijk, MSc) to address questions in a roundtable about the current and possible future business models for games for health.

  16. The Landau-Lifshitz equation describes the Ising spin correlation function in the free-fermion model

    CERN Document Server

    Rutkevich, S B

    1998-01-01

    We consider time and space dependence of the Ising spin correlation function in a continuous one-dimensional free-fermion model. By the Ising spin we imply the 'sign' variable, which takes alternating +-1 values in adjacent domains bounded by domain walls (fermionic world paths). The two-point correlation function is expressed in terms of the solution of the Cauchy problem for a nonlinear partial differential equation, which is proved to be equivalent to the exactly solvable Landau-Lifshitz equation. A new zero-curvature representation for this equation is presented. In turn, the initial condition for the Cauchy problem is given by the solution of a nonlinear ordinary differential equation, which has also been derived. In the Ising limit the above-mentioned partial and ordinary differential equations reduce to the sine-Gordon and Painleve III equations, respectively. (author)

  17. Model calculations of doubly closed shell nuclei in the integral-differential equation approach describing the two body correlations

    International Nuclear Information System (INIS)

    Brizzi, R.; Fabre de la Ripelle, M.; Lassaut, M.

    1999-01-01

    The binding energies and root mean square radii obtained from the Integro-Differential Equation Approach (IDEA) and from the Weight Function Approximation (WFA) of the IDEA for an even number of bosons and for 12 C, 16 O and 40 Ca are compared to those recently obtained by the Variational Monte Carlo, Fermi Hypernetted Chain and Coupled Cluster expansion method with model potentials. The IDEA provides numbers very similar to those obtained by other methods although it takes only two-body correlations into account. The analytical expression of the wave function for the WFA is given for bosons in ground state when the interaction pair is outside the potential range. Due to its simple structure, the equations of the IDEA can easily be extended to realistic interaction for nuclei like it has already been done for the tri-nucleon and the 4 He. (authors)

  18. A model for successful research partnerships: a New Brunswick experience.

    Science.gov (United States)

    Tamlyn, Karen; Creelman, Helen; Fisher, Garfield

    2002-01-01

    The purpose of this paper is to present an overview of a partnership model used to conduct a research study entitled "Needs of patients with cancer and their family members in New Brunswick Health Region 3 (NBHR3)" (Tamlyn-Leaman, Creelman, & Fisher, 1997). This partial replication study carried out by the three authors between 1995 and 1997 was a needs assessment, adapted with permission from previous work by Fitch, Vachon, Greenberg, Saltmarche, and Franssen (1993). In order to conduct a comprehensive needs assessment with limited resources, a partnership between academic, public, and private sectors was established. An illustration of this partnership is presented in the model entitled "A Client-Centred Partnership Model." The operations of this partnership, including the strengths, the perceived benefits, lessons learned by each partner, the barriers, and the process for conflict resolution, are described. A summary of the cancer care initiatives undertaken by NBHR3, which were influenced directly or indirectly by the recommendations from this study, is included.

  19. Development of a model to describe organic films on aerosol particles and cloud droplets. Final report; Entwicklung eines Modells zur Beschreibung organischer Filme auf Aerosolteilchen und Wolkentropfen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Forkel, R. (ed.); Seidl, W.

    2000-12-01

    Organic substances with polar groups are enriched on water surfaces and can form monomolecular surface films which can reduce the surface tension. A new model to describe surface films is presented, which describes in detail the film forming properties of fatty acids with up to 22 carbon atoms. The model is applied to measured concentrations of fatty acids (from the literature) in rain water and on aerosol particles and cloud droplets. An investigation of the sources of fatty acids has shown, that abrasion of the wax layer on leaves and needles is the main sources for surface film material in the western USA. Anthropogenic sources in urban areas are meat preparation and cigarette smoke. The agreement between model results and measurements when the model was applied to rain water confirms the original assumption that fatty acids are a main compound of surface films in rain water. For humid aerosol particles the application of the model on measured concentrations of fatty acids only showed strongly diluted films. Only for remote forest areas in western USA concentrated films were found, with the surface tension reduced by 20 to 30%. On cloud droplets the surface films is still more diluted than on aerosol particles. For all investigated cases the films was too much diluted to have an effect on the activation process of cloud droplets. (orig.) [German] Organische Substanzen mit polaren Gruppen reichern sich an der Wasseroberflaeche an und koennen monomolekulare Oberflaechenfilme bilden, die zu einer Verringerung der Oberflaechenspannung fuehren. Es wird ein neues Modell zur Beschreibung eines Oberflaechenfilms beschrieben, das detailliert die filmbildenden Eigenschaften der Fettsaeuren mit bis zu 22 Kohlenstoffatomen erfasst. Dieses Modell ist auf gemessene Konzentrationen von Fettsaeuren (Literaturdaten) in Regenwasser und auf atmosphaerischen Aerosolteilchen und Wolkentropfen angewandt worden. Eine Betrachtung der Quellen der Fettsaeuren zeigte, dass der Abrieb der

  20. The Influence of Quality on E-Commerce Success: An Empirical Application of the Delone and Mclean IS Success Model

    OpenAIRE

    Ultan Sharkey; Murray Scott; Thomas Acton

    2010-01-01

    This research addresses difficulties in measuring e-commerce success by implementing the DeLone and McLean (D&M) model of IS success (1992, 2003) in an e-commerce environment. This research considers the influence of quality on e-commerce success by measuring the information quality and system quality attributes of an e-commerce system and the intention to use, user satisfaction and intention to transact from a sample of respondents. This research provides an empirical e-commerce application ...

  1. Chaotic-Dynamical Conceptual Model to Describe Fluid Flow and Contaminant Transport in a Fractured Vadose Zone

    International Nuclear Information System (INIS)

    Faybishenko, Boris; Doughty, Christine; Geller, Jil T.

    1999-01-01

    DOE faces the remediation of numerous contaminated sites, such as those at Hanford, INEEL, LLNL, and LBNL, where organic and/or radioactive wastes were intentionally or accidentally released to the vadose zone from surface spills, underground tanks, cribs, shallow ponds, and deep wells. Migration of these contaminants through the vadose zone has led to the contamination of (or threatens to contaminate) underlying groundwater. A key issue in choosing a corrective action plan to clean up contaminated sites is the determination of the location, total mass, mobility and travel time to receptors for contaminants moving in the vadose zone. These problems are difficult to solve in a technically defensible and accurate manner because contaminants travel downward intermittently, through narrow pathways, driven by variations in environmental conditions. These preferential flow pathways can be difficult to find and predict. The primary objective of this project is to determine if and when dynamical chaos theory can be used to investigate infiltration of fluid and contaminant transport in heterogeneous soils and fractured rocks. The objective of this project is being achieved through the following activities: Development of multi scale conceptual models and mathematical and numerical algorithms for flow and transport, which incorporate both (a) the spatial variability of heterogeneous porous and fractured media and (b) the temporal dynamics of flow and transport; Development of appropriate experimental field and laboratory techniques needed to detect diagnostic parameters for chaotic behavior of flow; Evaluation of chaotic behavior of flow in laboratory and field experiments using methods from non-linear dynamics; Evaluation of the impact these dynamics may have on contaminant transport through heterogeneous fractured rocks and soils and remediation efforts. This approach is based on the consideration of multi scale spatial heterogeneity and flow phenomena that are affected by

  2. A plant wide aqueous phase chemistry model describing pH variations and ion speciation/pairing in wastewater treatment process models

    DEFF Research Database (Denmark)

    Flores-Alsina, X.; Mbamba, C. Kazadi; Solon, K.

    cationic/anionic loads. In this way, the general applicability/flexibility of the proposed approach is demonstrated by implementing the aqueous phase chemistry module in some of the most frequently used WWTP process simulation models. Finally, it is shown how traditional wastewater modelling studies can......, require a major, but unavoidable, additional degree of complexity when representing cationic/anionic behaviour in Activated Sludge (AS)/Anaerobic Digestion (AD) systems (Ikumi et al., 2014). In this paper, a plant-wide aqueous phase chemistry module describing pH variations plus ion speciation...... of Ordinary Differential Equations (ODEs) in order to reduce the overall stiffness of the system, thereby enhancing simulation speed. Additionally, a multi-dimensional version of the Newton-Raphson algorithm is applied to handle the existing multiple algebraic inter-dependencies (Solon et al., 2015...

  3. Development of an Electronic Portfolio System Success Model: An Information Systems Approach

    Science.gov (United States)

    Balaban, Igor; Mu, Enrique; Divjak, Blazenka

    2013-01-01

    This research has two main goals: to develop an instrument for assessing Electronic Portfolio (ePortfolio) success and to build a corresponding ePortfolio success model using DeLone and McLean's information systems success model as the theoretical framework. For this purpose, we developed an ePortfolio success measurement instrument and structural…

  4. LANDIS 4.0 users guide. LANDIS: a spatially explicit model of forest landscape disturbance, management, and succession

    Science.gov (United States)

    Hong S. He; Wei Li; Brian R. Sturtevant; Jian Yang; Bo Z. Shang; Eric J. Gustafson; David J. Mladenoff

    2005-01-01

    LANDIS 4.0 is new-generation software that simulates forest landscape change over large spatial and temporal scales. It is used to explore how disturbances, succession, and management interact to determine forest composition and pattern. Also describes software architecture, model assumptions and provides detailed instructions on the use of the model.

  5. Incorporation of FcRn-mediated disposition model to describe the population pharmacokinetics of therapeutic monoclonal IgG antibody in clinical patients.

    Science.gov (United States)

    Ng, Chee M

    2016-03-01

    The two-compartment linear model used to describe the population pharmacokinetics (PK) of many therapeutic monoclonal antibodies (TMAbs) offered little biological insight to antibody disposition in humans. The purpose of this study is to develop a semi-mechanistic FcRn-mediated IgG disposition model to describe the population PK of TMAbs in clinical patients. A standard two-compartment linear PK model from a previously published population PK model of pertuzumab was used to simulate intensive PK data of 100 subjects for model development. Two different semi-mechanistic FcRn-mediated IgG disposition models were developed and First Order Conditional Estimation (FOCE) with the interaction method in NONMEM was used to obtain the final model estimates. The performances of these models were then compared with the two-compartment linear PK model used to simulate the data for model development. A semi-mechanistic FcRn-mediated IgG disposition model consisting of a peripheral tissue compartment and FcRn-containing endosomes in the central compartment best describes the simulated pertuzumab population PK data. This developed semi-mechanistic population PK model had the same number of model parameters, produced very similar concentration-time profiles but provided additional biological insight to the FcRn-mediated IgG disposition in human subjects compared with the standard linear two-compartment linear PK model. This first reported semi-mechanistic model may serve as an important model framework for developing future population PK models of TMAbs in clinical patients. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Comparison of different two-pathway models for describing the combined effect of DO and nitrite on the nitrous oxide production by ammonia-oxidizing bacteria.

    Science.gov (United States)

    Lang, Longqi; Pocquet, Mathieu; Ni, Bing-Jie; Yuan, Zhiguo; Spérandio, Mathieu

    2017-02-01

    The aim of this work is to compare the capability of two recently proposed two-pathway models for predicting nitrous oxide (N 2 O) production by ammonia-oxidizing bacteria (AOB) for varying ranges of dissolved oxygen (DO) and nitrite. The first model includes the electron carriers whereas the second model is based on direct coupling of electron donors and acceptors. Simulations are confronted to extensive sets of experiments (43 batches) from different studies with three different microbial systems. Despite their different mathematical structures, both models could well and similarly describe the combined effect of DO and nitrite on N 2 O production rate and emission factor. The model-predicted contributions for nitrifier denitrification pathway and hydroxylamine pathway also matched well with the available isotopic measurements. Based on sensitivity analysis, calibration procedures are described and discussed for facilitating the future use of those models.

  7. An Analytic Model for the Success Rate of a Robotic Actuator System in Hitting Random Targets.

    Science.gov (United States)

    Bradley, Stuart

    2015-11-20

    Autonomous robotic systems are increasingly being used in a wide range of applications such as precision agriculture, medicine, and the military. These systems have common features which often includes an action by an "actuator" interacting with a target. While simulations and measurements exist for the success rate of hitting targets by some systems, there is a dearth of analytic models which can give insight into, and guidance on optimization, of new robotic systems. The present paper develops a simple model for estimation of the success rate for hitting random targets from a moving platform. The model has two main dimensionless parameters: the ratio of actuator spacing to target diameter; and the ratio of platform distance moved (between actuator "firings") to the target diameter. It is found that regions of parameter space having specified high success are described by simple equations, providing guidance on design. The role of a "cost function" is introduced which, when minimized, provides optimization of design, operating, and risk mitigation costs.

  8. The business of emergency medicine: a model for success.

    Science.gov (United States)

    Proctor, John; Hall, Peter; Carr, Janet

    2004-02-01

    Today's EPOs and their physicians face an array of daunting challenges. Falling reimbursement, rising malpractice costs. ED and hospital crowding,and demands for improving ED efficiency and patient satisfaction all contribute to the challenging and sometimes threatening environment of EM practice. The EP involved in a busy and often hectic ED shift may feel unduly and unnecessarily distracted when required to continuously acknowledge and address the business aspect of the practice. Nevertheless,regardless of the size and structure, fiscal viability ultimately determines the EPO's ability to continue to offer access to care. This article contends that a comprehensive business strategy drives superior financial performance and supports the organization's mission. The business strategy must identify financial and non-financial determinants of the EPO's success and provide a mechanism for understanding how the organization's resources are converted to value for customers. The section offers a framework for developing this strategy, for identifying possible gaps or deficiencies, and for measuring and monitoring progress in achieving strategic objectives and ultimately, the EPO's mission. The importance of the mission and the dynamic EM environment require that the strategy development process be more than an annual exercise for the leadership of the organization. Though key leaders in any size EPO--set the course for the organization, the entire organization must be aware and understand the strategy before they commit themselves and adopt actions and behaviors that promote it. The model presented here provides a graphic display that lends itself well to consistent communication of a comprehensive strategy in a concise way throughout the organization.Furthermore, the balance of the model, across four perspectives, recognizes the value of balanced organizational objectives and lends itself well to the creation of a measurement system that supports cause and effect

  9. Development and Application of a Category System to Describe Pre-Service Science Teachers' Activities in the Process of Scientific Modelling

    Science.gov (United States)

    Krell, Moritz; Walzer, Christine; Hergert, Susann; Krüger, Dirk

    2017-09-01

    As part of their professional competencies, science teachers need an elaborate meta-modelling knowledge as well as modelling skills in order to guide and monitor modelling practices of their students. However, qualitative studies about (pre-service) science teachers' modelling practices are rare. This study provides a category system which is suitable to analyse and to describe pre-service science teachers' modelling activities and to infer modelling strategies. The category system was developed based on theoretical considerations and was inductively refined within the methodological frame of qualitative content analysis. For the inductive refinement, modelling practices of pre-service teachers (n = 4) have been video-taped and analysed. In this study, one case was selected to demonstrate the application of the category system to infer modelling strategies. The contribution of this study for science education research and science teacher education is discussed.

  10. A model framework to describe growth-linked biodegradation of trace-level pesticides in the presence of coincidental carbon substrates and microbes

    DEFF Research Database (Denmark)

    Liu, Li; Helbling, Damian E.; Kohler, Hans-Peter E.

    2014-01-01

    described were: the growth-linked biodegradation of micropollutant at environmentally relevant concentrations; the effect of coincidental assimilable organic carbon substrates; and the effect of coincidental microbes that compete for assimilable organic carbon substrates. We used Monod kinetic models...... to describe substrate utilization and microbial growth rates for specific pesticide and degrader pairs. We then extended the model to include terms for utilization of assimilable organic carbon substrates by the specific degrader and coincidental microbes, growth on assimilable organic carbon substrates......, challenges remain in developing engineered remediation strategies for pesticide-contaminated environments because the fundamental processes that regulate growth-linked biodegradation of pesticides in natural environments remain poorly understood. In this research, we developed a model framework to describe...

  11. IS Success Model in E-Learning Context Based on Students' Perceptions

    Science.gov (United States)

    Freeze, Ronald D.; Alshare, Khaled A.; Lane, Peggy L.; Wen, H. Joseph

    2010-01-01

    This study utilized the Information Systems Success (ISS) model in examining e-learning systems success. The study was built on the premise that system quality (SQ) and information quality (IQ) influence system use and user satisfaction, which in turn impact system success. A structural equation model (SEM), using LISREL, was used to test the…

  12. A Blueprint for Success: A Model for Developing Engineering Education in the UK

    Directory of Open Access Journals (Sweden)

    Melanie Rose Nova King

    2014-03-01

    Full Text Available This paper details the emergence and development of the ‘Centre for Engineering and Design Education’ (CEDE at Loughborough University, UK, and provides a blueprint for success. With ample evidence that such a Centre can prove to be a highly effective support mechanism for discipline-specific academics and can develop and maintain valuable national and international networks and collaborations along with considerable esteem for the host university. The CEDE is unique in the UK and has achieved considerable success and recognition within the local engineering education community and beyond for the past 16 years. Here we discuss the historical background of the Centre’s development, the context in which it operates, and its effective management and operation strategy. The success it has enjoyed is described through examples, with much evidence of the generation of a significant amount of external funding; the development of high quality learning spaces; learning technology systems, open source software and improvements in curriculum design; a strong record of research and publication on the pedagogy of engineering; strong links with industry and employers; and a wealth of connections and know-how built up over the years. This paper provides the institutions with a model blueprint for success in developing engineering education.

  13. Determinants of Business Success – Theoretical Model and Empirical Verification

    Directory of Open Access Journals (Sweden)

    Kozielski Robert

    2016-12-01

    Full Text Available Market knowledge, market orientation, learning competencies, and a business performance were the key issues of the research project conducted in the 2006 study. The main findings identified significant relationships between the independent variables (market knowledge, market orientation, learning competencies and the dependent variables (business success. A partial correlation analysis indicated that a business success primarily relies on organisational learning competencies. Organisational learning competencies, to a large extent (almost 60%, may be explained by the level of corporate market knowledge and market orientation. The aim of the paper is to evaluate to what extent the relationships between the variables are still valid. The research was based on primary and secondary data sources. The major field of the research was carried out in the form of quantitative studies. The results of the 2014 study are consistent with the previous (2006 results.

  14. A nurse manager succession planning model with associated empirical outcomes.

    Science.gov (United States)

    Titzer, Jennifer L; Shirey, Maria R; Hauck, Sheila

    2014-01-01

    Perceptions of leadership and management competency after a formal nurse manager succession planning program were evaluated. A lack of strategic workforce planning and development of a leadership pipeline contributes to a predicted nurse manager shortage. To meet the anticipated needs for future leadership, evidence-based action is critical. A quasi-experimental mixed-methods, 1-group pretest/posttest research design was used. Nurses working in an acute care hospital were recruited for the study and selected using an objective evaluative process. Participant perceptions regarding their leadership and management competencies significantly increased after the leadership program. Program evaluations confirmed that participants found the program beneficial. One year after program completion, 100% of the program participants have been retained at the organization and 73% had transitioned to leadership roles. Succession planning and leadership development serve as beneficial and strategic mechanisms for identifying and developing high-potential individuals for leadership positions, contributing toward the future nursing leadership pipeline.

  15. Concepts, challenges, and successes in modeling thermodynamics of metabolism.

    Science.gov (United States)

    Cannon, William R

    2014-01-01

    The modeling of the chemical reactions involved in metabolism is a daunting task. Ideally, the modeling of metabolism would use kinetic simulations, but these simulations require knowledge of the thousands of rate constants involved in the reactions. The measurement of rate constants is very labor intensive, and hence rate constants for most enzymatic reactions are not available. Consequently, constraint-based flux modeling has been the method of choice because it does not require the use of the rate constants of the law of mass action. However, this convenience also limits the predictive power of constraint-based approaches in that the law of mass action is used only as a constraint, making it difficult to predict metabolite levels or energy requirements of pathways. An alternative to both of these approaches is to model metabolism using simulations of states rather than simulations of reactions, in which the state is defined as the set of all metabolite counts or concentrations. While kinetic simulations model reactions based on the likelihood of the reaction derived from the law of mass action, states are modeled based on likelihood ratios of mass action. Both approaches provide information on the energy requirements of metabolic reactions and pathways. However, modeling states rather than reactions has the advantage that the parameters needed to model states (chemical potentials) are much easier to determine than the parameters needed to model reactions (rate constants). Herein, we discuss recent results, assumptions, and issues in using simulations of state to model metabolism.

  16. Creating a Model for Graduate Student Inclusion and Success

    Science.gov (United States)

    Duranczyk, Irene M.; Franko, Jennifer; Osifuye, Shade'; Barton, Amy; Higbee, Jeanne L.

    2015-01-01

    Mentoring and advising are critical aspects of the graduate student experience, and can have a significant impact on the professional lives of future postsecondary faculty and staff and a rippling effect throughout higher education and the global economy. This paper describes the process a new department undertook to create a graduate program that…

  17. Modeling antecedents of electronic medical record system implementation success in low-resource setting hospitals.

    Science.gov (United States)

    Tilahun, Binyam; Fritz, Fleur

    2015-08-01

    With the increasing implementation of Electronic Medical Record Systems (EMR) in developing countries, there is a growing need to identify antecedents of EMR success to measure and predict the level of adoption before costly implementation. However, less evidence is available about EMR success in the context of low-resource setting implementations. Therefore, this study aims to fill this gap by examining the constructs and relationships of the widely used DeLone and MacLean (D&M) information system success model to determine whether it can be applied to measure EMR success in those settings. A quantitative cross sectional study design using self-administered questionnaires was used to collect data from 384 health professionals working in five governmental hospitals in Ethiopia. The hospitals use a comprehensive EMR system since three years. Descriptive and structural equation modeling methods were applied to describe and validate the extent of relationship of constructs and mediating effects. The findings of the structural equation modeling shows that system quality has significant influence on EMR use (β = 0.32, P quality has significant influence on EMR use (β = 0.44, P service quality has strong significant influence on EMR use (β = 0.36, P effect of EMR use on user satisfaction was not significant. Both EMR use and user satisfaction have significant influence on perceived net-benefit (β = 0.31, P mediating factor in the relationship between service quality and EMR use (P effect on perceived net-benefit of health professionals. EMR implementers and managers in developing countries are in urgent need of implementation models to design proper implementation strategies. In this study, the constructs and relationships depicted in the updated D&M model were found to be applicable to assess the success of EMR in low resource settings. Additionally, computer literacy was found to be a mediating factor in EMR use and user satisfaction of

  18. Successes and failures of the constituent quark model

    International Nuclear Information System (INIS)

    Lipkin, H.J.

    1982-01-01

    Our approach considers the model as a possible bridge between QCD and the experimental data and examines its predictions to see where these succeed and where they fail. We also attempt to improve the model by looking for additional simple assumptions which give better fits to the experimental data. But we avoid complicated models with too many ad hoc assumptions and too many free parameters; these can fit everything but teach us nothing. We define our constituent quark model by analogy with the constituent electron model of the atom and the constituent nucleon model of the nucleus. In the same way that an atom is assumed to consist only of constituent electrons and a central Coulomb field and a nucleus is assumed to consist only of constituent nucleons hadrons are assumed to consist only of their constituent valence quarks with no bag, no glue, no ocean, nor other constituents. Although these constituent models are oversimplified and neglect other constituents we push them as far as we can. Atomic physics has photons and vacuum polarization as well as constituent electrons, but the constituent model is adequate for calculating most features of the spectrum when finer details like the Lamb shift are neglected. 54 references

  19. Improving Rice Modeling Success Rate with Ternary Non-structural Fertilizer Response Model.

    Science.gov (United States)

    Li, Juan; Zhang, Mingqing; Chen, Fang; Yao, Baoquan

    2018-06-13

    Fertilizer response modelling is an important technical approach to realize metrological fertilization on rice. With the goal of solving the problems of a low success rate of a ternary quadratic polynomial model (TPFM) and to expand the model's applicability, this paper established a ternary non-structural fertilizer response model (TNFM) based on the experimental results from N, P and K fertilized rice fields. Our research results showed that the TNFM significantly improved the modelling success rate by addressing problems arising from setting the bias and multicollinearity in a TPFM. The results from 88 rice field trials in China indicated that the proportion of typical TNFMs that satisfy the general fertilizer response law of plant nutrition was 40.9%, while the analogous proportion of TPFMs was only 26.1%. The recommended fertilization showed a significant positive linear correlation between the two models, and the parameters N 0 , P 0 and K 0 that estimated the value of soil supplying nutrient equivalents can be used as better indicators of yield potential in plots where no N or P or K fertilizer was applied. The theoretical analysis showed that the new model has a higher fitting accuracy and a wider application range.

  20. Application of the dosimetric model described by Humm to target 131I monoclonal antibodies to leukaemic cells in the cerebrospinal fluid

    International Nuclear Information System (INIS)

    Papanastassiou, V.; Pizer, B.L.; Kemshead, J.T.

    1993-01-01

    In 1986 Humm suggested a dosimetric model for targeted radiation therapy that considered both the physical characteristics of the radionuclide used and the morphology of the targeted tumour. Using this model he described the dose advantage due to antibody binding in terms of a ratio of tumour radiation dose to that of normal tissue. The model applied to non-solid tumours assumes no cell clumping and hence no cross-fire effect. The authors demonstrate the direct application of the model to a particular clinical scenario; the targeting of 131 I monoclonal antibodies to leukaemic cells within the cerebrospinal fluid (CSF). In this situation the dose advantage is much higher than the figure reported by Humm, which was arrived at by considering a more general application of the model. (author)

  1. A Multi-Stage Maturity Model for Long-Term IT Outsourcing Relationship Success

    Science.gov (United States)

    Luong, Ming; Stevens, Jeff

    2015-01-01

    The Multi-Stage Maturity Model for Long-Term IT Outsourcing Relationship Success, a theoretical stages-of-growth model, explains long-term success in IT outsourcing relationships. Research showed the IT outsourcing relationship life cycle consists of four distinct, sequential stages: contract, transition, support, and partnership. The model was…

  2. A Model for Physician Leadership Development and Succession Planning.

    Science.gov (United States)

    Dubinsky, Isser; Feerasta, Nadia; Lash, Rick

    2015-01-01

    Although the presence of physicians in formal leadership positions has often been limited to roles of department chiefs, MAC chairs, etc., a growing number of organizations are recruiting physicians to other leadership positions (e.g., VP, CEO) where their involvement is being genuinely sought and valued. While physicians have traditionally risen to leadership positions based on clinical excellence or on a rotational basis, truly effective physician leadership that includes competencies such as strategic planning, budgeting, mentoring, network development, etc., is essential to support organizational goals, improve performance and overall efficiency as well as ensuring the quality of care. In this context, the authors have developed a physician leader development and succession planning matrix and supporting toolkit to assist hospitals in identifying and nurturing the next generation of physician leaders.

  3. LINEAR MIXED MODEL TO DESCRIBE THE BASAL AREA INCREMENT FOR INDIVUDUAL CEDRO (Cedrela odorata L.TREES IN OCCIDENTAL AMAZON, BRAZIL

    Directory of Open Access Journals (Sweden)

    Thiago Augusto da Cunha

    2013-01-01

    Full Text Available Reliable growth data from trees are important to establish a rational forest management. Characteristics from trees, like the size, crown architecture and competition indices have been used to mathematically describe the increment efficiently when associated with them. However, the precise role of these effects in the growth-modeling destined to tropical trees needs to be further studied. Here it is reconstructed the basal area increment (BAI of individual Cedrela odorata trees, sampled at Amazon forest, to develop a growth- model using potential-predictors like: (1 classical tree size; (2 morphometric data; (3 competition and (4 social position including liana loads. Despite the large variation in tree size and growth, we observed that these kinds of predictor variables described well the BAI in level of individual tree. The fitted mixed model achieve a high efficiency (R2=92.7 % and predicted 3-years BAI over bark for trees of Cedrela odorata ranging from 10 to 110 cm at diameter at breast height. Tree height, steam slenderness and crown formal demonstrated high influence in the BAI growth model and explaining most of the growth variance (Partial R2=87.2%. Competition variables had negative influence on the BAI, however, explained about 7% of the total variation. The introduction of a random parameter on the regressions model (mixed modelprocedure has demonstrated a better significance approach to the data observed and showed more realistic predictions than the fixed model.

  4. A model framework to describe growth-linked biodegradation of trace-level pollutants in the presence of coincidental carbon substrates and microbes.

    Science.gov (United States)

    Liu, Li; Helbling, Damian E; Kohler, Hans-Peter E; Smets, Barth F

    2014-11-18

    Pollutants such as pesticides and their degradation products occur ubiquitously in natural aquatic environments at trace concentrations (μg L(-1) and lower). Microbial biodegradation processes have long been known to contribute to the attenuation of pesticides in contaminated environments. However, challenges remain in developing engineered remediation strategies for pesticide-contaminated environments because the fundamental processes that regulate growth-linked biodegradation of pesticides in natural environments remain poorly understood. In this research, we developed a model framework to describe growth-linked biodegradation of pesticides at trace concentrations. We used experimental data reported in the literature or novel simulations to explore three fundamental kinetic processes in isolation. We then combine these kinetic processes into a unified model framework. The three kinetic processes described were: the growth-linked biodegradation of micropollutant at environmentally relevant concentrations; the effect of coincidental assimilable organic carbon substrates; and the effect of coincidental microbes that compete for assimilable organic carbon substrates. We used Monod kinetic models to describe substrate utilization and microbial growth rates for specific pesticide and degrader pairs. We then extended the model to include terms for utilization of assimilable organic carbon substrates by the specific degrader and coincidental microbes, growth on assimilable organic carbon substrates by the specific degrader and coincidental microbes, and endogenous metabolism. The proposed model framework enables interpretation and description of a range of experimental observations on micropollutant biodegradation. The model provides a useful tool to identify environmental conditions with respect to the occurrence of assimilable organic carbon and coincidental microbes that may result in enhanced or reduced micropollutant biodegradation.

  5. Our sun. I. The standard model: Successes and failures

    International Nuclear Information System (INIS)

    Sackmann, I.J.; Boothroyd, A.I.; Fowler, W.A.

    1990-01-01

    The results of computing a number of standard solar models are reported. A presolar helium content of Y = 0.278 is obtained, and a Cl-37 capture rate of 7.7 SNUs, consistently several times the observed rate of 2.1 SNUs, is determined. Thus, the solar neutrino problem remains. The solar Z value is determined primarily by the observed Z/X ratio and is affected very little by differences in solar models. Even large changes in the low-temperature molecular opacities have no effect on Y, nor even on conditions at the base of the convective envelope. Large molecular opacities do cause a large increase in the mixing-length parameter alpha but do not cause the convective envelope to reach deeper. The temperature remains too low for lithium burning, and there is no surface lithium depletion; thus, the lithium problem of the standard solar model remains. 103 refs

  6. Landsat analysis of tropical forest succession employing a terrain model

    Science.gov (United States)

    Barringer, T. H.; Robinson, V. B.; Coiner, J. C.; Bruce, R. C.

    1980-01-01

    Landsat multispectral scanner (MSS) data have yielded a dual classification of rain forest and shadow in an analysis of a semi-deciduous forest on Mindonoro Island, Philippines. Both a spatial terrain model, using a fifth side polynomial trend surface analysis for quantitatively estimating the general spatial variation in the data set, and a spectral terrain model, based on the MSS data, have been set up. A discriminant analysis, using both sets of data, has suggested that shadowing effects may be due primarily to local variations in the spectral regions and can therefore be compensated for through the decomposition of the spatial variation in both elevation and MSS data.

  7. The European Distribution of Sus Scrofa. Model Outputs from the Project Described within the Poster – Where are All the Boars? An Attempt to Gain a Continental Perspective

    Directory of Open Access Journals (Sweden)

    Neil Stewart Alexander

    2016-01-01

    Full Text Available Wild boar is a host of a number of arthropod-vectored diseases and its numbers are on the rise in mainland Europe. The species potentially impacts ecosystems, humans and farming practices and so its distribution is of interest to policy makers in a number of fields beyond that of the primarily epidemiological goal of this study. Three statistical model outputs describing the distribution and abundance of the species Sus scrofa (Wild boar are included in this data package. The extent of this dataset covers continental Europe. These data were presented as a poster [1] at the conference Genes, Ecosystems and Risk of Infection (GERI 2015. The first of the three models provide a European map presenting the probability of presence of Sus scrofa, which can be used to describe the likely geographical distribution of the species. The second and third models provide indices to help describe the likely abundance across the continent. The two indices include “the proportion of suitable habitat where presence is estimated” and a simple classification of boar abundance across Europe using quantiles of existing abundance data and proxies.

  8. Teaching Modeling with Partial Differential Equations: Several Successful Approaches

    Science.gov (United States)

    Myers, Joseph; Trubatch, David; Winkel, Brian

    2008-01-01

    We discuss the introduction and teaching of partial differential equations (heat and wave equations) via modeling physical phenomena, using a new approach that encompasses constructing difference equations and implementing these in a spreadsheet, numerically solving the partial differential equations using the numerical differential equation…

  9. Pharmacobezoars described and demystified.

    Science.gov (United States)

    Simpson, Serge-Emile

    2011-02-01

    A bezoar is a concretion of foreign material that forms and persists in the gastrointestinal tract. Bezoars are classified by their material origins. Phytobezoars contain plant material, trichobezoars contain hair, lactobezoars contain milk proteins, and pharmacobezoars contain pharmaceutical products. Tablets, suspensions, and even insoluble drug delivery vehicles can, on rare occasions, and sometimes under specific circumstances, form pharmacobezoars. The goal of this review is to catalog and examine all of the available reports in the English language medical literature that convincingly describe the formation and management of pharmacobezoars. Articles included in this review were identified by performing searches using the terms "bezoar," "pharmacobezoar," and "concretion" in the following databases: OVID MEDLINE, PubMed, and JSTOR. The complete MEDLINE and JSTOR holdings were included in the search without date ranges. The results were limited to English language publications. Articles that described nonmedication bezoars were not included in the review. Articles describing phytobezoars, food bezoars, fecal impactions, illicit drug packet ingestions, enteral feeding material bezoars, and hygroscopic diet aid bezoars were excluded. The bibliographic references within the articles already accumulated were then examined in order to gather additional pharmacobezoar cases. The cases are grouped by pharmaceutical agent that formed the bezoar, and groupings are arranged in alphabetical order. Discussions and conclusions specific to each pharmaceutical agent are included in that agent's subheading. Patterns and themes that emerged in the review of the assembled case reports are reviewed and presented in a more concise format. Pharmacobezoars form under a wide variety of circumstances and in a wide variety of patients. They are difficult to diagnose reliably. Rules for suspecting, diagnosing, and properly managing a pharmacobezoar are highly dependent on the

  10. [Deep mycoses rarely described].

    Science.gov (United States)

    Charles, D

    1986-01-01

    Beside deep mycoses very well known: histoplasmosis, candidosis, cryptococcosis, there are other mycoses less frequently described. Some of them are endemic in some countries: South American blastomycosis in Brazil, coccidioidomycosis in California; some others are cosmopolitan and may affect everyone: sporotrichosis, or may affect only immunodeficient persons: mucormycosis. They do not spare Africa, we may encounter basidiobolomycosis, rhinophycomycosis, dermatophytosis, sporotrichosis and, more recently reported, rhinosporidiosis. Important therapeutic progresses have been accomplished with amphotericin B and with antifungus imidazole compounds (miconazole and ketoconazole). Surgical intervention is sometime recommended in chromomycosis and rhinosporidiosis.

  11. Low-dimensional models of ‘Neuro-glio-vascular unit’ for describing neural dynamics under normal and energy-starved conditions

    Directory of Open Access Journals (Sweden)

    Karishma eChhabria

    2016-03-01

    Full Text Available The motivation of developing simple minimal models for neuro-glio-vascular system arises from a recent modeling study elucidating the bidirectional information flow within the neuro-glio-vascular system having 89 dynamic equations (Chander and Chakravarthy 2012. While this was one of the first attempts at formulating a comprehensive model for neuro-glia-vascular system, it poses severe restrictions in scaling up to network levels. On the contrary, low dimensional models are convenient devices in simulating large networks that also provide an intuitive understanding of the complex interactions occurring within the neuro-glio-vascular system. The key idea underlying the proposed models is to describe the glio-vascular system as a lumped system which takes neural firing rate as input and returns an ‘energy’ variable (analogous to ATP as output. To this end we present two models: Biophysical neuro-energy (Model #1 with 5 variables, comprising of KATP channel activity governed by neuronal ATP dynamics and the Dynamic threshold (Model #2 with 3 variables depicting the dependence of neural firing threshold on the ATP dynamics. Both the models show different firing regimes such as continuous spiking, phasic and tonic bursting depending on the ATP production coefficient, εp and external current. We then demonstrate that in a network comprising of such energy-dependent neuron units, εp could modulate the Local field potential (LFP frequency and amplitude. Interestingly, low frequency LFP dominates under low εp conditions, which is thought to be reminiscent of seizure-like activity observed in epilepsy. The proposed ‘neuron-energy’ unit may be implemented in building models of neuro-glio-vascular networks to simulate data obtained from multimodal neuroimaging systems such as fNIRS-EEG and fMRI-EEG. Such models could also provide a theoretical basis for devising optimal neurorehabilitation strategies such as non-invasive brain stimulation for

  12. Low-Dimensional Models of "Neuro-Glio-Vascular Unit" for Describing Neural Dynamics under Normal and Energy-Starved Conditions.

    Science.gov (United States)

    Chhabria, Karishma; Chakravarthy, V Srinivasa

    2016-01-01

    The motivation of developing simple minimal models for neuro-glio-vascular (NGV) system arises from a recent modeling study elucidating the bidirectional information flow within the NGV system having 89 dynamic equations (1). While this was one of the first attempts at formulating a comprehensive model for neuro-glio-vascular system, it poses severe restrictions in scaling up to network levels. On the contrary, low--dimensional models are convenient devices in simulating large networks that also provide an intuitive understanding of the complex interactions occurring within the NGV system. The key idea underlying the proposed models is to describe the glio-vascular system as a lumped system, which takes neural firing rate as input and returns an "energy" variable (analogous to ATP) as output. To this end, we present two models: biophysical neuro-energy (Model 1 with five variables), comprising KATP channel activity governed by neuronal ATP dynamics, and the dynamic threshold (Model 2 with three variables), depicting the dependence of neural firing threshold on the ATP dynamics. Both the models show different firing regimes, such as continuous spiking, phasic, and tonic bursting depending on the ATP production coefficient, ɛp, and external current. We then demonstrate that in a network comprising such energy-dependent neuron units, ɛp could modulate the local field potential (LFP) frequency and amplitude. Interestingly, low-frequency LFP dominates under low ɛp conditions, which is thought to be reminiscent of seizure-like activity observed in epilepsy. The proposed "neuron-energy" unit may be implemented in building models of NGV networks to simulate data obtained from multimodal neuroimaging systems, such as functional near infrared spectroscopy coupled to electroencephalogram and functional magnetic resonance imaging coupled to electroencephalogram. Such models could also provide a theoretical basis for devising optimal neurorehabilitation strategies, such as

  13. A Model of Social Selection and Successful Altruism

    Science.gov (United States)

    1989-10-07

    D., The evolution of social behavior. Annual Reviews of Ecological Systems, 5:325-383 (1974). 2. Dawkins , R., The selfish gene . Oxford: Oxford...alive and well. it will be important to re- examine this striking historical experience,-not in terms o, oversimplified models of the " selfish gene ," but...Darwinian Analysis The acceptance by many modern geneticists of the axiom that the basic unit of selection Is the " selfish gene " quickly led to the

  14. The secret to successful solute-transport modeling

    Science.gov (United States)

    Konikow, Leonard F.

    2011-01-01

    Modeling subsurface solute transport is difficult—more so than modeling heads and flows. The classical governing equation does not always adequately represent what we see at the field scale. In such cases, commonly used numerical models are solving the wrong equation. Also, the transport equation is hyperbolic where advection is dominant, and parabolic where hydrodynamic dispersion is dominant. No single numerical method works well for all conditions, and for any given complex field problem, where seepage velocity is highly variable, no one method will be optimal everywhere. Although we normally expect a numerically accurate solution to the governing groundwater-flow equation, errors in concentrations from numerical dispersion and/or oscillations may be large in some cases. The accuracy and efficiency of the numerical solution to the solute-transport equation are more sensitive to the numerical method chosen than for typical groundwater-flow problems. However, numerical errors can be kept within acceptable limits if sufficient computational effort is expended. But impractically long

  15. Observational constraints on successful model of quintessential Inflation

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Chao-Qiang [Chongqing University of Posts and Telecommunications, Chongqing, 400065 (China); Lee, Chung-Chi [DAMTP, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Sami, M. [Centre for Theoretical Physics, Jamia Millia Islamia, New Delhi 110025 (India); Saridakis, Emmanuel N. [Physics Division, National Technical University of Athens, 15780 Zografou Campus, Athens (Greece); Starobinsky, Alexei A., E-mail: geng@phys.nthu.edu.tw, E-mail: lee.chungchi16@gmail.com, E-mail: sami@iucaa.ernet.in, E-mail: Emmanuel_Saridakis@baylor.edu, E-mail: alstar@landau.ac.ru [L. D. Landau Institute for Theoretical Physics RAS, Moscow 119334 (Russian Federation)

    2017-06-01

    We study quintessential inflation using a generalized exponential potential V (φ)∝ exp(−λ φ {sup n} / M {sub Pl} {sup n} ), n >1, the model admits slow-roll inflation at early times and leads to close-to-scaling behaviour in the post inflationary era with an exit to dark energy at late times. We present detailed investigations of the inflationary stage in the light of the Planck 2015 results, study post-inflationary dynamics and analytically confirm the existence of an approximately scaling solution. Additionally, assuming that standard massive neutrinos are non-minimally coupled, makes the field φ dominant once again at late times giving rise to present accelerated expansion of the Universe. We derive observational constraints on the field and time-dependent neutrino masses. In particular, for n =6 (8), the parameter λ is constrained to be, log λ > −7.29 (−11.7); the model produces the spectral index of the power spectrum of primordial scalar (matter density) perturbations as n {sub s} = 0.959 ± 0.001 (0.961 ± 0.001) and tiny tensor-to-scalar ratio, r <1.72 × 10{sup −2} (2.32 × 10{sup −2}) respectively. Consequently, the upper bound on possible values of the sum of neutrino masses Σ m {sub ν} ∼< 2.5 eV significantly enhances compared to that in the standard ΛCDM model.

  16. Observational constraints on successful model of quintessential Inflation

    International Nuclear Information System (INIS)

    Geng, Chao-Qiang; Lee, Chung-Chi; Sami, M.; Saridakis, Emmanuel N.; Starobinsky, Alexei A.

    2017-01-01

    We study quintessential inflation using a generalized exponential potential V (φ)∝ exp(−λ φ n / M Pl n ), n >1, the model admits slow-roll inflation at early times and leads to close-to-scaling behaviour in the post inflationary era with an exit to dark energy at late times. We present detailed investigations of the inflationary stage in the light of the Planck 2015 results, study post-inflationary dynamics and analytically confirm the existence of an approximately scaling solution. Additionally, assuming that standard massive neutrinos are non-minimally coupled, makes the field φ dominant once again at late times giving rise to present accelerated expansion of the Universe. We derive observational constraints on the field and time-dependent neutrino masses. In particular, for n =6 (8), the parameter λ is constrained to be, log λ > −7.29 (−11.7); the model produces the spectral index of the power spectrum of primordial scalar (matter density) perturbations as n s = 0.959 ± 0.001 (0.961 ± 0.001) and tiny tensor-to-scalar ratio, r <1.72 × 10 −2 (2.32 × 10 −2 ) respectively. Consequently, the upper bound on possible values of the sum of neutrino masses Σ m ν ∼< 2.5 eV significantly enhances compared to that in the standard ΛCDM model.

  17. Modeling Forest Succession among Ecological Land Units in Northern Minnesota

    Directory of Open Access Journals (Sweden)

    George Host

    1998-12-01

    Full Text Available Field and modeling studies were used to quantify potential successional pathways among fine-scale ecological classification units within two geomorphic regions of north-central Minnesota. Soil and overstory data were collected on plots stratified across low-relief ground moraines and undulating sand dunes. Each geomorphic feature was sampled across gradients of topography or soil texture. Overstory conditions were sampled using five variable-radius point samples per plot; soil samples were analyzed for carbon and nitrogen content. Climatic, forest composition, and soil data were used to parameterize the sample plots for use with LINKAGES, a forest growth model that simulates changes in composition and soil characteristics over time. Forest composition and soil properties varied within and among geomorphic features. LINKAGES simulations were using "bare ground" and the current overstory as starting conditions. Northern hardwoods or pines dominated the late-successional communities of morainal and dune landforms, respectively. The morainal landforms were dominated by yellow birch and sugar maple; yellow birch reached its maximum abundance in intermediate landscape positions. On the dune sites, pine was most abundant in drier landscape positions, with white spruce increasing in abundance with increasing soil moisture and N content. The differences in measured soil properties and predicted late-successional composition indicate that ecological land units incorporate some of the key variables that govern forest composition and structure. They further show the value of ecological classification and modeling for developing forest management strategies that incorporate the spatial and temporal dynamics of forest ecosystems.

  18. Brandon mathematical model describing the effect of calcination and reduction parameters on specific surface area of UO{sub 2} powders

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Nguyen Trong; Thuan, Le Ba [Institute for Technology of Radioactive and Rare Elements (ITRRE), 48 Lang Ha, Dong Da, Ha Noi (Viet Nam); Van Khoai, Do [Micro-Emission Ltd., 1-1 Asahidai, Nomi, Ishikawa, 923-1211 (Japan); Lee, Jin-Young, E-mail: jinlee@kigam.re.kr [Convergence Research Center for Development of Mineral Resources (DMR), Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon, 305-350 (Korea, Republic of); Jyothi, Rajesh Kumar, E-mail: rkumarphd@kigam.re.kr [Convergence Research Center for Development of Mineral Resources (DMR), Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon, 305-350 (Korea, Republic of)

    2016-06-15

    Uranium dioxide (UO{sub 2}) powder has been widely used to prepare fuel pellets for commercial light water nuclear reactors. Among typical characteristics of the powder, specific surface area (SSA) is one of the most important parameter that determines the sintering ability of UO{sub 2} powder. This paper built up a mathematical model describing the effect of the fabrication parameters on SSA of UO{sub 2} powders. To the best of our knowledge, the Brandon model is used for the first time to describe the relationship between the essential fabrication parameters [reduction temperature (T{sub R}), calcination temperature (T{sub C}), calcination time (t{sub C}) and reduction time (t{sub R})] and SSA of the obtained UO{sub 2} powder product. The proposed model was tested with Wilcoxon's rank sum test, showing a good agreement with the experimental parameters. The proposed model can be used to predict and control the SSA of UO{sub 2} powder.

  19. A plant-wide aqueous phase chemistry module describing pH variations and ion speciation/pairing in wastewater treatment process models.

    Science.gov (United States)

    Flores-Alsina, Xavier; Kazadi Mbamba, Christian; Solon, Kimberly; Vrecko, Darko; Tait, Stephan; Batstone, Damien J; Jeppsson, Ulf; Gernaey, Krist V

    2015-11-15

    There is a growing interest within the Wastewater Treatment Plant (WWTP) modelling community to correctly describe physico-chemical processes after many years of mainly focusing on biokinetics. Indeed, future modelling needs, such as a plant-wide phosphorus (P) description, require a major, but unavoidable, additional degree of complexity when representing cationic/anionic behaviour in Activated Sludge (AS)/Anaerobic Digestion (AD) systems. In this paper, a plant-wide aqueous phase chemistry module describing pH variations plus ion speciation/pairing is presented and interfaced with industry standard models. The module accounts for extensive consideration of non-ideality, including ion activities instead of molar concentrations and complex ion pairing. The general equilibria are formulated as a set of Differential Algebraic Equations (DAEs) instead of Ordinary Differential Equations (ODEs) in order to reduce the overall stiffness of the system, thereby enhancing simulation speed. Additionally, a multi-dimensional version of the Newton-Raphson algorithm is applied to handle the existing multiple algebraic inter-dependencies. The latter is reinforced with the Simulated Annealing method to increase the robustness of the solver making the system not so dependent of the initial conditions. Simulation results show pH predictions when describing Biological Nutrient Removal (BNR) by the activated sludge models (ASM) 1, 2d and 3 comparing the performance of a nitrogen removal (WWTP1) and a combined nitrogen and phosphorus removal (WWTP2) treatment plant configuration under different anaerobic/anoxic/aerobic conditions. The same framework is implemented in the Benchmark Simulation Model No. 2 (BSM2) version of the Anaerobic Digestion Model No. 1 (ADM1) (WWTP3) as well, predicting pH values at different cationic/anionic loads. In this way, the general applicability/flexibility of the proposed approach is demonstrated, by implementing the aqueous phase chemistry module in some

  20. On track for success: an innovative behavioral science curriculum model.

    Science.gov (United States)

    Freedy, John R; Carek, Peter J; Dickerson, Lori M; Mallin, Robert M

    2013-01-01

    This article describes the behavioral science curriculum currently in place at the Trident/MUSC Family Medicine Residency Program. The Trident/MUSC Program is a 10-10-10 community-based, university-affiliated program in Charleston, South Carolina. Over the years, the Trident/MUSC residency program has graduated over 400 Family Medicine physicians. The current behavioral science curriculum consists of both required core elements (didactic lectures, clinical observation, Balint groups, and Resident Grand Rounds) as well as optional elements (longitudinal patient care experiences, elective rotations, behavioral science editorial experience, and scholars project with a behavioral science focus). All Trident/MUSC residents complete core behavioral science curriculum elements and are free to participate in none, some, or all of the optional behavioral science curriculum elements. This flexibility allows resident physicians to tailor the educational program in a manner to meet individual educational needs. The behavioral science curriculum is based upon faculty interpretation of existing "best practice" guidelines (Residency Review Committee-Family Medicine and AAFP). This article provides sufficient curriculum detail to allow the interested reader the opportunity to adapt elements of the behavioral science curriculum to other residency training programs. While this behavioral science track system is currently in an early stage of implementation, the article discusses track advantages as well as future plans to evaluate various aspects of this innovative educational approach.

  1. The Integrated Medical Model: Statistical Forecasting of Risks to Crew Health and Mission Success

    Science.gov (United States)

    Fitts, M. A.; Kerstman, E.; Butler, D. J.; Walton, M. E.; Minard, C. G.; Saile, L. G.; Toy, S.; Myers, J.

    2008-01-01

    The Integrated Medical Model (IMM) helps capture and use organizational knowledge across the space medicine, training, operations, engineering, and research domains. The IMM uses this domain knowledge in the context of a mission and crew profile to forecast crew health and mission success risks. The IMM is most helpful in comparing the risk of two or more mission profiles, not as a tool for predicting absolute risk. The process of building the IMM adheres to Probability Risk Assessment (PRA) techniques described in NASA Procedural Requirement (NPR) 8705.5, and uses current evidence-based information to establish a defensible position for making decisions that help ensure crew health and mission success. The IMM quantitatively describes the following input parameters: 1) medical conditions and likelihood, 2) mission duration, 3) vehicle environment, 4) crew attributes (e.g. age, sex), 5) crew activities (e.g. EVA's, Lunar excursions), 6) diagnosis and treatment protocols (e.g. medical equipment, consumables pharmaceuticals), and 7) Crew Medical Officer (CMO) training effectiveness. It is worth reiterating that the IMM uses the data sets above as inputs. Many other risk management efforts stop at determining only likelihood. The IMM is unique in that it models not only likelihood, but risk mitigations, as well as subsequent clinical outcomes based on those mitigations. Once the mathematical relationships among the above parameters are established, the IMM uses a Monte Carlo simulation technique (a random sampling of the inputs as described by their statistical distribution) to determine the probable outcomes. Because the IMM is a stochastic model (i.e. the input parameters are represented by various statistical distributions depending on the data type), when the mission is simulated 10-50,000 times with a given set of medical capabilities (risk mitigations), a prediction of the most probable outcomes can be generated. For each mission, the IMM tracks which conditions

  2. Pseudospin model to describe transport properties in Bi2Sr2(CazPr1-z)Cu2O8+y

    International Nuclear Information System (INIS)

    Bastone, E.C.; Pires, A.S.T.; Silva, P.R.

    2001-01-01

    A pseudo-spin model is proposed, as a means to describe some transport properties (resistivity and Hall mobility) in Bi 2 Sr 2 (Ca z Pr 1-z )Cu 2 O 8+y . Our model is based in a double-well potential where tunneling in a given site and interaction between different lattice sites are allowed only through the excited states. Doping of the pure system by the addition of Pr increases the ratio between the activation energy and the tunneling constant. The model Hamiltonian displays some features which are present in the hydrogen-bonded ferroelectrics. Its dynamics is treated in the random phase approximation and the characteristic frequency (time) is used in a Drude formula in order to obtain some transport properties of the system, namely the electric resistivity and the Hall mobility. The quantities calculated in this work are compared with the experimental data given by Beschoten et al. (1996). (orig.)

  3. LANDPLANER (LANDscape, Plants, LANdslide and ERosion): a model to describe the dynamic response of slopes (or basins) under different changing scenarios

    Science.gov (United States)

    Rossi, Mauro; Torri, Dino; Santi, Elisa; Bacaro, Giovanni; Marchesini, Ivan

    2014-05-01

    approaches have been proposed to model separately landslide and erosion processes, only few attempts were made to model both jointly, mostly integrating pre-existing models. To overcome this limitation we develop a new model called LANDPLANER (LANDscape, Plants, LANdslide and ERosion), specifically design to describe the dynamic response of slopes (or basins) under different changing scenarios including: (i) changes of meteorological factors, (ii) changes of vegetation or land-use, (iii) and changes of slope morphology. The was applied in different study area in order to check its basic assumptions, and to test its general operability and applicability. Results show a reasonable model behaviors and confirm its easy applicability in real cases.

  4. The social networking application success model : An empirical study of Facebook and Twitter

    NARCIS (Netherlands)

    Ou, Carol; Davison, R.M.; Huang, Q.

    2016-01-01

    Social networking applications (SNAs) are among the fastest growing web applications of recent years. In this paper, we propose a causal model to assess the success of SNAs, grounded on DeLone and McLean’s updated information systems (IS) success model. In addition to their original three dimensions

  5. Secondary Science Teachers Making Sense of Model-Based Classroom Instruction: Understanding the Learning and Learning Pathways Teachers Describe as Supporting Changes in Teaching Practice

    Science.gov (United States)

    Hvidsten, Connie J.

    Connie J. Hvidsten September 2016 Education Secondary Science Teachers Making Sense of Model-Based Classroom Instruction: Understanding the Learning and Learning Pathways Teachers Describe as Supporting Changes in Teaching Practice This dissertation consists of three papers analyzing writings and interviews of experienced secondary science teachers during and after a two-year professional development (PD) program focused on model-based reasoning (MBR). MBR is an approach to science instruction that provides opportunities for students to use conceptual models to make sense of natural phenomena in ways that are similar to the use of models within the scientific community. The aim of this research is to better understand the learning and learning pathways teachers identified as valuable in supporting changes in their teaching practice. To accomplish this aim, the papers analyze the ways teachers 1) ascribe their learning to various aspects of the program, 2) describe what they learned, and 3) reflect on the impact the PD had on their teaching practice. Twenty-one secondary science teachers completed the Innovations in Science Instruction through Modeling (ISIM) program from 2007 through 2009. Commonalities in the written reflections and interview responses led to a set of generalizable findings related to the impacts and outcomes of the PD. The first of the three papers describes elements of the ISIM program that teachers associated with their own learning. One of the most frequently mentioned PD feature was being in the position of an adult learner. Embedding learning in instructional practice by collaboratively developing and revising lessons, and observing the lessons in one-another's classrooms provided a sense of professional community, accountability, and support teachers reported were necessary to overcome the challenges of implementing new pedagogical practices. Additionally, teachers described that opportunities to reflect on their learning and connect their

  6. WE-AB-BRA-02: Development of Biomechanical Models to Describe Dose-Volume Response to Liver Stereotactic Body Radiation Therapy (SBRT) Patients

    International Nuclear Information System (INIS)

    McCulloch, M; Polan, D; Feng, M; Lawrence, T; Haken, R Ten; Brock, K

    2015-01-01

    Purpose: Previous studies have shown that radiotherapy treatment for liver metastases causes marked liver hypertrophy in areas receiving low dose and atrophy/fibrosis in areas receiving high dose. The purpose of this work is to develop and evaluate a biomechanical model-based dose-response model to describe these liver responses to SBRT. Methods: In this retrospective study, a biomechanical model-based deformable registration algorithm, Morfeus, was expanded to include dose-based boundary conditions. Liver and tumor volumes were contoured on the planning images and CT/MR images three months post-RT and converted to finite element models. A thermal expansion-based relationship correlating the delivered dose and volume response was generated from 22 patients previously treated. This coefficient, combined with the planned dose, was applied as an additional boundary condition to describe the volumetric response of the liver of an additional cohort of metastatic liver patients treated with SBRT. The accuracy of the model was evaluated based on overall volumetric liver comparisons and the target registration error (TRE) using the average deviations in positions of identified vascular bifurcations on each set of registered images, with a target accuracy of the 2.5mm isotropic dose grid (vector dimension 4.3mm). Results: The thermal expansion coefficient models the volumetric change of the liver to within 3%. The accuracy of Morfeus with dose-expansion boundary conditions a TRE of 5.7±2.8mm compared to 11.2±3.7mm using rigid registration and 8.9±0.28mm using Morfeus with only spatial boundary conditions. Conclusion: A biomechanical model has been developed to describe the volumetric and spatial response of the liver to SBRT. This work will enable the improvement of correlating functional imaging with delivered dose, the mapping of the delivered dose from one treatment onto the planning images for a subsequent treatment, and will further provide information to assist

  7. New Described Dermatological Disorders

    Directory of Open Access Journals (Sweden)

    Müzeyyen Gönül

    2014-01-01

    Full Text Available Many advances in dermatology have been made in recent years. In the present review article, newly described disorders from the last six years are presented in detail. We divided these reports into different sections, including syndromes, autoinflammatory diseases, tumors, and unclassified disease. Syndromes included are “circumferential skin creases Kunze type” and “unusual type of pachyonychia congenita or a new syndrome”; autoinflammatory diseases include “chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE syndrome,” “pyoderma gangrenosum, acne, and hidradenitis suppurativa (PASH syndrome,” and “pyogenic arthritis, pyoderma gangrenosum, acne, and hidradenitis suppurativa (PAPASH syndrome”; tumors include “acquired reactive digital fibroma,” “onychocytic matricoma and onychocytic carcinoma,” “infundibulocystic nail bed squamous cell carcinoma,” and “acral histiocytic nodules”; unclassified disorders include “saurian papulosis,” “symmetrical acrokeratoderma,” “confetti-like macular atrophy,” and “skin spicules,” “erythema papulosa semicircularis recidivans.”

  8. A new predictive dynamic model describing the effect of the ambient temperature and the convective heat transfer coefficient on bacterial growth.

    Science.gov (United States)

    Ben Yaghlene, H; Leguerinel, I; Hamdi, M; Mafart, P

    2009-07-31

    In this study, predictive microbiology and food engineering were combined in order to develop a new analytical model predicting the bacterial growth under dynamic temperature conditions. The proposed model associates a simplified primary bacterial growth model without lag, the secondary Ratkowsky "square root" model and a simplified two-parameter heat transfer model regarding an infinite slab. The model takes into consideration the product thickness, its thermal properties, the ambient air temperature, the convective heat transfer coefficient and the growth parameters of the micro organism of concern. For the validation of the overall model, five different combinations of ambient air temperature (ranging from 8 degrees C to 12 degrees C), product thickness (ranging from 1 cm to 6 cm) and convective heat transfer coefficient (ranging from 8 W/(m(2) K) to 60 W/(m(2) K)) were tested during a cooling procedure. Moreover, three different ambient air temperature scenarios assuming alternated cooling and heating stages, drawn from real refrigerated food processes, were tested. General agreement between predicted and observed bacterial growth was obtained and less than 5% of the experimental data fell outside the 95% confidence bands estimated by the bootstrap percentile method, at all the tested conditions. Accordingly, the overall model was successfully validated for isothermal and dynamic refrigeration cycles allowing for temperature dynamic changes at the centre and at the surface of the product. The major impact of the convective heat transfer coefficient and the product thickness on bacterial growth during the product cooling was demonstrated. For instance, the time needed for the same level of bacterial growth to be reached at the product's half thickness was estimated to be 5 and 16.5 h at low and high convection level, respectively. Moreover, simulation results demonstrated that the predicted bacterial growth at the air ambient temperature cannot be assumed to be

  9. A plant-wide aqueous phase chemistry module describing pH variations and ion speciation/pairing in wastewater treatment process models

    DEFF Research Database (Denmark)

    Flores Alsina, Xavier; Kazadi Mbamba, Christian; Solon, Kimberly

    2015-01-01

    at different cationic/anionic loads. In this way, the general applicability/flexibility of the proposed approach is demonstrated, by implementing the aqueous phase chemistry module in some of the most frequently used WWTP process simulation models. Finally, it is shown how traditional wastewater modelling......, but unavoidable, additional degree of complexity when representing cationic/anionic behaviour in Activated Sludge (AS)/Anaerobic Digestion (AD) systems. In this paper, a plant-wide aqueous phase chemistry module describing pH variations plus ion speciation/pairing is presented and interfaced with industry......) in order to reduce the overall stiffness of the system, thereby enhancing simulation speed. Additionally, a multi-dimensional version of the Newton-Raphson algorithm is applied to handle the existing multiple algebraic inter-dependencies. The latter is reinforced with the Simulated Annealing method...

  10. Unifying Pore Network Modeling, Continuous Time Random Walk (CTRW) Theory and Experiment to Describe Impact of Spatial Heterogeneities on Solute Dispersion at Multiple Length-scales

    Science.gov (United States)

    Bijeljic, B.; Blunt, M. J.; Rhodes, M. E.

    2009-04-01

    This talk will describe and highlight the advantages offered by a novel methodology that unifies pore network modeling, CTRW theory and experiment in description of solute dispersion in porous media. Solute transport in a porous medium is characterized by the interplay of advection and diffusion (described by Peclet number, Pe) that cause dispersion of solute particles. Dispersion is traditionally described by dispersion coefficients, D, that are commonly calculated from the spatial moments of the plume. Using a pore-scale network model based on particle tracking, the rich Peclet-number dependence of dispersion coefficient is predicted from first principles and is shown to compare well with experimental data for restricted diffusion, transition, power-law and mechanical dispersion regimes in the asymptotic limit. In the asymptotic limit D is constant and can be used in an averaged advection-dispersion equation. However, it is highly important to recognize that, until the velocity field is fully sampled, the particle transport is non-Gaussian and D possesses temporal or spatial variation. Furthermore, temporal probability density functions (PDF) of tracer particles are studied in pore networks and an excellent agreement for the spectrum of transition times for particles from pore to pore is obtained between network model results and CTRW theory. Based on the truncated power-law interpretation of PDF-s, the physical origin of the power-law scaling of dispersion coefficient vs. Peclet number has been explained for unconsolidated porous media, sands and a number of sandstones, arriving at the same conclusion from numerical network modelling, analytic CTRW theory and experiment. The length traveled by solute plumes before Gaussian behaviour is reached increases with an increase in heterogeneity and/or Pe. This opens up the question on the nature of dispersion in natural systems where the heterogeneities at the larger scales will significantly increase the range of

  11. Designing for sustained adoption: A model of developing educational innovations for successful propagation

    Science.gov (United States)

    Khatri, Raina; Henderson, Charles; Cole, Renée; Froyd, Jeffrey E.; Friedrichsen, Debra; Stanford, Courtney

    2016-06-01

    [This paper is part of the Focused Collection on Preparing and Supporting University Physics Educators.] The physics education research community has produced a wealth of knowledge about effective teaching and learning of college level physics. Based on this knowledge, many research-proven instructional strategies and teaching materials have been developed and are currently available to instructors. Unfortunately, these intensive research and development activities have failed to influence the teaching practices of many physics instructors. This paper describes interim results of a larger study to develop a model of designing materials for successful propagation. The larger study includes three phases, the first two of which are reported here. The goal of the first phase was to characterize typical propagation practices of education developers, using data from a survey of 1284 National Science Foundation (NSF) principal investigators and focus group data from eight disciplinary groups of NSF program directors. The goal of the second phase was to develop an understanding of successful practice by studying three instructional strategies that have been well propagated. The result of the first two phases is a tentative model of designing for successful propagation, which will be further validated in the third phase through purposeful sampling of additional well-propagated instructional strategies along with typical education development projects. We found that interaction with potential adopters was one of the key missing ingredients in typical education development activities. Education developers often develop a polished product before getting feedback, rely on mass-market communication channels for dissemination, and do not plan for supporting adopters during implementation. The tentative model resulting from this study identifies three key propagation activities: interactive development, interactive dissemination, and support of adopters. Interactive development

  12. A model for estimating the minimum number of offspring to sample in studies of reproductive success.

    Science.gov (United States)

    Anderson, Joseph H; Ward, Eric J; Carlson, Stephanie M

    2011-01-01

    Molecular parentage permits studies of selection and evolution in fecund species with cryptic mating systems, such as fish, amphibians, and insects. However, there exists no method for estimating the number of offspring that must be assigned parentage to achieve robust estimates of reproductive success when only a fraction of offspring can be sampled. We constructed a 2-stage model that first estimated the mean (μ) and variance (v) in reproductive success from published studies on salmonid fishes and then sampled offspring from reproductive success distributions simulated from the μ and v estimates. Results provided strong support for modeling salmonid reproductive success via the negative binomial distribution and suggested that few offspring samples are needed to reject the null hypothesis of uniform offspring production. However, the sampled reproductive success distributions deviated significantly (χ(2) goodness-of-fit test p value reproductive success distribution at rates often >0.05 and as high as 0.24, even when hundreds of offspring were assigned parentage. In general, reproductive success patterns were less accurate when offspring were sampled from cohorts with larger numbers of parents and greater variance in reproductive success. Our model can be reparameterized with data from other species and will aid researchers in planning reproductive success studies by providing explicit sampling targets required to accurately assess reproductive success.

  13. Empirical model based on Weibull distribution describing the destruction kinetics of natural microbiota in pineapple (Ananas comosus L.) puree during high-pressure processing.

    Science.gov (United States)

    Chakraborty, Snehasis; Rao, Pavuluri Srinivasa; Mishra, Hari Niwas

    2015-10-15

    High pressure inactivation of natural microbiota viz. aerobic mesophiles (AM), psychrotrophs (PC), yeasts and molds (YM), total coliforms (TC) and lactic acid bacteria (LAB) in pineapple puree was studied within the experimental domain of 0.1-600 MPa and 30-50 °C with a treatment time up to 20 min. A complete destruction of yeasts and molds was obtained at 500 MPa/50 °C/15 min; whereas no counts were detected for TC and LAB at 300 MPa/30 °C/15 min. A maximum of two log cycle reductions was obtained for YM during pulse pressurization at the severe process intensity of 600 MPa/50 °C/20 min. The Weibull model clearly described the non-linearity of the survival curves during the isobaric period. The tailing effect, as confirmed by the shape parameter (β) of the survival curve, was obtained in case of YM (β1) was observed for the other microbial groups. Analogous to thermal death kinetics, the activation energy (Ea, kJ·mol(-1)) and the activation volume (Va, mL·mol(-1)) values were computed further to describe the temperature and pressure dependencies of the scale parameter (δ, min), respectively. A higher δ value was obtained for each microbe at a lower temperature and it decreased with an increase in pressure. A secondary kinetic model was developed describing the inactivation rate (k, min(-1)) as a function of pressure (P, MPa) and temperature (T, K) including the dependencies of Ea and Va on P and T, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. CAMDYN: a new model to describe the axial motion of molten fuel inside the pin of a fast breeder reactor during accident conditions

    International Nuclear Information System (INIS)

    Peter, G.

    1991-01-01

    The new in-pin fuel motion model CAMDYN (Cavity Material Dynamics) describes the axial motion of both partially and fully molten fuel inside the pin of a fast breeder reactor during accident conditions. The motion of the two types of molten fuel and the imbedded fission gas bubbles is treated both before and after cladding failure. The basic modelling approach consists of the treatment of two one-dimensional flows which are coupled by interaction terms. Each of these flows is treated compressively and with axially variable flow cross sections. The mass and energy equations of both fields are solved explicitly using upwind differencing on a fixed Eulerian grid. The two momentum equations are solved simultaneously, using the convective momentum fluxes of the previous timestep. Both partially and fully molten fuel can move axially into a central hole extending to the plenum in the case of certain hollow pellet designs. The fuel temperature calculation includes the determination of a radial temperature profile. A simple conduction freezing model is included. After cladding failure, ejection into the coolant channel is modeled

  15. Measuring online learning systems success: applying the updated DeLone and McLean model.

    Science.gov (United States)

    Lin, Hsiu-Fen

    2007-12-01

    Based on a survey of 232 undergraduate students, this study used the updated DeLone and McLean information systems success model to examine the determinants for successful use of online learning systems (OLS). The results provided an expanded understanding of the factors that measure OLS success. The results also showed that system quality, information quality, and service quality had a significant effect on actual OLS use through user satisfaction and behavioral intention to use OLS.

  16. Function-centered modeling of engineering systems using the goal tree-success tree technique and functional primitives

    International Nuclear Information System (INIS)

    Modarres, Mohammad; Cheon, Se Woo

    1999-01-01

    Most of the complex systems are formed through some hierarchical evolution. Therefore, those systems can be best described through hierarchical frameworks. This paper describes some fundamental attributes of complex physical systems and several hierarchies such as functional, behavioral, goal/condition, and event hierarchies, then presents a function-centered approach to system modeling. Based on the function-centered concept, this paper describes the joint goal tree-success tree (GTST) and the master logic diagram (MLD) as a framework for developing models of complex physical systems. A function-based lexicon for classifying the most common elements of engineering systems for use in the GTST-MLD framework has been proposed. The classification is based on the physical conservation laws that govern the engineering systems. Functional descriptions based on conservation laws provide a simple and rich vocabulary for modeling complex engineering systems

  17. A parametric model to describe neutron spectra around high-energy electron accelerators and its application in neutron spectrometry with Bonner Spheres

    Science.gov (United States)

    Bedogni, Roberto; Pelliccioni, Maurizio; Esposito, Adolfo

    2010-03-01

    Due to the increased interest of the scientific community in the applications of synchrotron light, there is an increasing demand of high-energy electron facilities, testified by the construction of several new facilities worldwide. The radiation protection around such facilities requires accurate experimental methods to determine the dose due to prompt radiation fields. Neutron fields, in particular, are the most complex to measure, because they extend in energy from thermal (10 -8 MeV) up to hundreds MeV and because the responses of dosemeters and survey meters usually have large energy dependence. The Bonner Spheres Spectrometer (BSS) is in practice the only instrument able to respond over the whole energy range of interest, and for this reason it is frequently used to derive neutron spectra and dosimetric quantities in accelerator workplaces. Nevertheless, complex unfolding algorithms are needed to derive the neutron spectra from the experimental BSS data. This paper presents a parametric model specially developed for the unfolding of the experimental data measured with BSS around high-energy electron accelerators. The work consists of the following stages: (1) Generation with the FLUKA code, of a set of neutron spectra representing the radiation environment around accelerators with different electron energies; (2) formulation of a parametric model able to describe these spectra, with particular attention to the high-energy component (>10 MeV), which may be responsible for a large part of the dose in workplaces; and (3) implementation of this model in an existing unfolding code.

  18. A parametric model to describe neutron spectra around high-energy electron accelerators and its application in neutron spectrometry with Bonner Spheres

    International Nuclear Information System (INIS)

    Bedogni, Roberto; Pelliccioni, Maurizio; Esposito, Adolfo

    2010-01-01

    Due to the increased interest of the scientific community in the applications of synchrotron light, there is an increasing demand of high-energy electron facilities, testified by the construction of several new facilities worldwide. The radiation protection around such facilities requires accurate experimental methods to determine the dose due to prompt radiation fields. Neutron fields, in particular, are the most complex to measure, because they extend in energy from thermal (10 -8 MeV) up to hundreds MeV and because the responses of dosemeters and survey meters usually have large energy dependence. The Bonner Spheres Spectrometer (BSS) is in practice the only instrument able to respond over the whole energy range of interest, and for this reason it is frequently used to derive neutron spectra and dosimetric quantities in accelerator workplaces. Nevertheless, complex unfolding algorithms are needed to derive the neutron spectra from the experimental BSS data. This paper presents a parametric model specially developed for the unfolding of the experimental data measured with BSS around high-energy electron accelerators. The work consists of the following stages: (1) Generation with the FLUKA code, of a set of neutron spectra representing the radiation environment around accelerators with different electron energies; (2) formulation of a parametric model able to describe these spectra, with particular attention to the high-energy component (>10 MeV), which may be responsible for a large part of the dose in workplaces; and (3) implementation of this model in an existing unfolding code.

  19. An investigation of potential success factors for an introductory model-driven programming course

    DEFF Research Database (Denmark)

    Bennedsen, Jens; Caspersen, Michael Edelgaard

    2005-01-01

    In order to improve the course design of a CS1 model-driven programming course we study potential indicators of success for such a course. We explain our specific interpretation of objects-first. Of eight potential indicators of success, we have found only two to be significant at a 95% confidence...

  20. National culture and business model change: a framework for successful expansions

    DEFF Research Database (Denmark)

    Dalby, J.; Nielsen, L.S.; Lueg, Rainer

    2014-01-01

    Dalby, J., Nielsen, Lueg, R., L. S., Pedersen, L., Tomoni, A. C. 2014. National culture and business model change: a framework for successful expansions. Journal of Enterprising Culture, 22(4): 379-498.......Dalby, J., Nielsen, Lueg, R., L. S., Pedersen, L., Tomoni, A. C. 2014. National culture and business model change: a framework for successful expansions. Journal of Enterprising Culture, 22(4): 379-498....

  1. A Weibull model to describe antimicrobial kinetics of oregano and lemongrass essential oils against Salmonella Enteritidis in ground beef during refrigerated storage.

    Science.gov (United States)

    de Oliveira, Thales Leandro Coutinho; Soares, Rodrigo de Araújo; Piccoli, Roberta Hilsdorf

    2013-03-01

    The antimicrobial effect of oregano (Origanum vulgare L.) and lemongrass (Cymbopogon citratus (DC.) Stapf.) essential oils (EOs) against Salmonella enterica serotype Enteritidis in in vitro experiments, and inoculated in ground bovine meat during refrigerated storage (4±2 °C) for 6 days was evaluated. The Weibull model was tested to fit survival/inactivation bacterial curves (estimating of p and δ parameters). The minimum inhibitory concentration (MIC) value for both EOs on S. Enteritidis was 3.90 μl/ml. The EO concentrations applied in the ground beef were 3.90, 7.80 and 15.60 μl/g, based on MIC levels and possible activity reduction by food constituents. Both evaluated EOs in all tested levels, showed antimicrobial effects, with microbial populations reducing (p≤0.05) along time storage. Evaluating fit-quality parameters (RSS and RSE) Weibull models are able to describe the inactivation curves of EOs against S. Enteritidis. The application of EOs in processed meats can be used to control pathogens during refrigerated shelf-life. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Model of Islamic Social Entrepreneurship: A Study on Successful Muslim Social Entrepreneur in Malaysia

    Directory of Open Access Journals (Sweden)

    Boulven Mohd Adib

    2018-01-01

    Full Text Available Since research effort in the area is minimal, there is a clear need to examine the practice of Islamic social entrepreneurship among successful Muslim social entrepreneurs in Malaysia. One such practice is to organize charitable activities to benefit the community through the gains made from entrepreneurial activities that are based on social mission and vision. The research problem is lacking of model on Islamic social entrepreneurship. The main objective of this paper is to develop a Model of Islamic Social Entrepreneurship based on successful Muslim social entrepreneur in Malaysia. The research method used in this study is literature review, content analysis, and interview with 14 participants constituting nine successful Muslim social entrepreneurs and five experts with religious academic backgrounds participated in the study. The research finding shows that model of Islamic social entrepreneurship is the major contribution of the study which could serve as guidelines for successful Muslim social entrepreneurs, particularly young entrepreneurs.

  3. Mathematical models to describe iontophoretic transport in vitro and in vivo and the effect of current application on the skin barrier.

    Science.gov (United States)

    Gratieri, Taís; Kalia, Yogeshvar N

    2013-02-01

    more esoteric "constant phase element"; the latter provides a better mathematical description of the "non-ideal" behaviour of skin impedance. However, in addition to simply providing a "mathematical" fit of the observed data, it is essential to relate these circuit elements to biological structures present in the skin. More recently, attention has also turned to what happens when the permeant crosses the epidermis and reaches the systemic circulation and pharmacokinetic models have been proposed to interpret data from iontophoretic delivery studies in vivo. Here, we provide an overview of mathematical models that have been proposed to describe (i) the effect of current application on the skin and the implications for potential iontophoretic transport pathways, (ii) electrotransport kinetics and (iii) the fate of iontophoretically delivered drugs once they enter the systemic circulation. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Describing and analysing primary health care system support for chronic illness care in Indigenous communities in Australia's Northern Territory – use of the Chronic Care Model

    Directory of Open Access Journals (Sweden)

    Stewart Allison

    2008-05-01

    Full Text Available Abstract Background Indigenous Australians experience disproportionately high prevalence of, and morbidity and mortality from chronic illness such as diabetes, renal disease and cardiovascular disease. Improving the understanding of how Indigenous primary care systems are organised to deliver chronic illness care will inform efforts to improve the quality of care for Indigenous people. Methods This cross-sectional study was conducted in 12 Indigenous communities in Australia's Northern Territory. Using the Chronic Care Model as a framework, we carried out a mail-out survey to collect information on material, financial and human resources relating to chronic illness care in participating health centres. Follow up face-to-face interviews with health centre staff were conducted to identify successes and difficulties in the systems in relation to providing chronic illness care to community members. Results Participating health centres had distinct areas of strength and weakness in each component of systems: 1 organisational influence – strengthened by inclusion of chronic illness goals in business plans, appointment of designated chronic disease coordinators and introduction of external clinical audits, but weakened by lack of training in disease prevention and health promotion and limited access to Medicare funding; 2 community linkages – facilitated by working together with community organisations (e.g. local stores and running community-based programs (e.g. "health week", but detracted by a shortage of staff especially of Aboriginal health workers working in the community; 3 self management – promoted through patient education and goal setting with clients, but impeded by limited focus on family and community-based activities due to understaffing; 4 decision support – facilitated by distribution of clinical guidelines and their integration with daily care, but limited by inadequate access to and support from specialists; 5 delivery system

  5. Examining Management Success Potential.

    Science.gov (United States)

    Quatrano, Louis A.

    The derivation of a model of management success potential in hospitals or health services administration is described. A questionnaire developed to assess management success potential in health administration students was voluntarily completed by approximately 700 incoming graduate students in 35 university health services administration programs…

  6. Sharing Responsibility for College Success: A Model Partnership Moves Students to Diplomas and Degrees

    Science.gov (United States)

    Vargas, Joel

    2014-01-01

    In order to prepare the large number of postsecondary-educated youth our economy demands, high schools and higher education must break through the boundaries that have traditionally separated them and assume joint responsibility for student success. This brief describes an unusual school district partnership with colleges that has achieved…

  7. Assessing eGovernment Systems Success: A Validation of the DeLone and McLean Model of Information Systems Success

    Science.gov (United States)

    Wang, Yi-Shun; Liao, Yi-Wen

    2008-01-01

    With the proliferation of the Internet and World Wide Web applications, people are increasingly interacting with government to citizen (G2C) eGovernment systems. It is therefore important to measure the success of G2C eGovernment systems from the citizen's perspective. While general information systems (IS) success models have received much…

  8. External Validation of a Prediction Model for Successful External Cephalic Version

    NARCIS (Netherlands)

    de Hundt, Marcella; Vlemmix, Floortje; Kok, Marjolein; van der Steeg, Jan W.; Bais, Joke M.; Mol, Ben W.; van der Post, Joris A.

    2012-01-01

    We sought external validation of a prediction model for the probability of a successful external cephalic version (ECV). We evaluated the performance of the prediction model with calibration and discrimination. For clinical practice, we developed a score chart to calculate the probability of a

  9. Career and Technical Education (CTE) Student Success in Community Colleges: A Conceptual Model

    Science.gov (United States)

    Hirschy, Amy S.; Bremer, Christine D.; Castellano, Marisa

    2011-01-01

    Career and technical education (CTE) students pursuing occupational associate's degrees or certificates differ from students seeking academic majors at 2-year institutions in several ways. This article examines several theoretical models of student persistence and offers a conceptual model of student success focused on CTE students in community…

  10. North Dakota's Experience with the Academy Model: A Successful Replication

    Science.gov (United States)

    Hall, Tom; Clapper, Ann

    2016-01-01

    In this article, professors share how the district/university partnership model thriving at Kansas State University was successfully replicated in North Dakota, and was adapted to match their own department goals. While teacher leadership has become a theme among Kansas State academies, their model was created out of principal preparation efforts.…

  11. Modeling management information systems’ success: a study in the domain of further education and training

    CSIR Research Space (South Africa)

    Visser, M

    2012-10-01

    Full Text Available was applied in a survey at one public FET college to evaluate the success of the MIS deployed at the college. Findings from the survey lead to the refinement of the model which is also articulated in this paper and reflected as the SAFETMIS model. The paper...

  12. Modeling Success: Using Preenrollment Data to Identify Academically At-Risk Students

    Science.gov (United States)

    Gansemer-Topf, Ann M.; Compton, Jonathan; Wohlgemuth, Darin; Forbes, Greg; Ralston, Ekaterina

    2015-01-01

    Improving student success and degree completion is one of the core principles of strategic enrollment management. To address this principle, institutional data were used to develop a statistical model to identify academically at-risk students. The model employs multiple linear regression techniques to predict students at risk of earning below a…

  13. Privatization: The Use of Risk, Economic and Finance Models to Ensure Its Success

    International Nuclear Information System (INIS)

    Jaksch, John A.; Weimar, Mark R.; Young, Joan K.; Taylor, William J.; Furlong, Peter T.; Feldman, Roger D.; Diprinzio, Ray

    2001-01-01

    The article describes the use of risk, economic and financial models as they were used to help DOE in their decision-making processes on TWRS Privatization. The article describes how the models were used to allocate risk between the contractor and DOE, evaluate whether DOE should accept certain risk allocations, how the economic and financial models were used to evaluate whether the government was receiving the best bid price and whether any money was being saved by using privatization, and evaluated alternative financing schemes. The paper also describes how the financial model was used to evaluate and negotiate the pricing structure which became a part of the contract.

  14. Interpersonal success factors for strategy implementation: a case study using group model building

    OpenAIRE

    Rodney J Scott; Robert Y Cavana; Donald Cameron

    2015-01-01

    Strategy implementation has been identified as an area of system dynamics literature requiring greater attention. Most strategies fail to be implemented successfully, and processes for effectively implementing strategy are yet to be fully explained and explored. The reported interpersonal success factors for strategy implementation are reported outcomes for group model building, suggesting potential applicability. A case study using validated survey methods yielded promising results, and sugg...

  15. Proposing a Model for Successful Application of Knowledge Sharing II (Social Knowledge Sharing) within Organizations

    OpenAIRE

    Mehdi Shamizanjani; Seyed Mohammad Ghasemtabar Shahri

    2014-01-01

    The main purpose of this research is the development of a success model of Knowledge Sharing 2.0 (social knowledge sharing) through organizations. A three-step strategy is used in this research as stated below: In the first step, identification of social software and extraction of factors effective on success of each for knowledge sharing were obtained from literature review. Execution of Delphi method and identification of critical factors were done in the second step. At l...

  16. Knowledge management driven leadership, culture and innovation success – an integrative model

    OpenAIRE

    Zieba, M.; Schivinski, Bruno

    2015-01-01

    Purpose - This article examines the relation between knowledge management (KM) driven leadership, culture and innovation success of knowledge-intensive small and medium sized companies. By building on the previously reported research on leadership, culture, innovation , and knowledge management, we synergistically integrate d KM-driven leadership and innovation success while exploring the meditational role of culture in that. Design/methodology/approach - A conceptual model comprising three c...

  17. describing a collaborative clothing design process between

    African Journals Online (AJOL)

    user

    ISSN 0378-5254 Journal of Family Ecology and Consumer Sciences, Vol 43, 2015. Designing success: describing a ... PROCESS BETWEEN APPRENTICE DESIGNERS AND EXPERT DESIGN .... 5 Evaluation and decisions. (a) Outcomes.

  18. Economic sustainability in franchising: a model to predict franchisor success or failure

    OpenAIRE

    Calderón Monge, Esther; Pastor Sanz, Ivan .; Huerta Zavala, Pilar Angélica

    2017-01-01

    As a business model, franchising makes a major contribution to gross domestic product (GDP). A model that predicts franchisor success or failure is therefore necessary to ensure economic sustainability. In this study, such a model was developed by applying Lasso regression to a sample of franchises operating between 2002 and 2013. For franchises with the highest likelihood of survival, the franchise fees and the ratio of company-owned to franchised outlets were suited to the age ...

  19. Online revenue models in the media sector: an exploratory study on their success factors and adoption

    OpenAIRE

    Stienstra, Martin R.; Ruel, Hubertus Johannes Maria; Boerrigter, Thomas

    2010-01-01

    Especially for companies in the media sector such as publishers, the Internet has created new strategic and commercial opportunities. However, many companies in the media sector are struggling with how to adapt their business and revenue model for doing profitable business online. This exploratory study goes into the success factors and the level of adoption of online revenue models by media sector companies. We use Chaffey (2002) in determining online revenue models in which we included Oste...

  20. Validation of the DeLone and McLean Information Systems Success Model

    OpenAIRE

    Ojo, Adebowale I.

    2017-01-01

    Objectives This study is an adaptation of the widely used DeLone and McLean information system success model in the context of hospital information systems in a developing country. Methods A survey research design was adopted in the study. A structured questionnaire was used to collect data from 442 health information management personnel in five Nigerian teaching hospitals. A structural equation modeling technique was used to validate the model's constructs. Results It was revealed that syst...

  1. Open Source Software Success Model for Iran: End-User Satisfaction Viewpoint

    Directory of Open Access Journals (Sweden)

    Ali Niknafs

    2012-03-01

    Full Text Available The open source software development is notable option for software companies. Recent years, many advantages of this software type are cause of move to that in Iran. National security and international restrictions problems and also software and services costs and more other problems intensified importance of use of this software. Users and their viewpoints are the critical success factor in the software plans. But there is not an appropriate model for open source software case in Iran. This research tried to develop a measuring open source software success model for Iran. By use of data gathered from open source users and online survey the model was tested. The results showed that components by positive effect on open source success were user satisfaction, open source community services quality, open source quality, copyright and security.

  2. A Partial Test and Development of Delone and Mclean's Model of IS Success

    Directory of Open Access Journals (Sweden)

    Peter Seddon

    1996-11-01

    Full Text Available DeLone and McLean's (1992 comprehensive review of different information system success measures concludes with a model of interrelationships between six IS Success constructs. This paper critically examines the meaning of four of these constructs and the evidence of relationships between them. It then provides results from empirical tests of these relationships. Tests are conducted using both conventional ordinary least squares regression path analysis and structural equation modeling - with substantially similar results. The empirical results provide substantial support for the "up stream" two thirds of DeLone and McLean's model. Three factors. System Quality, Information Quality, and Usefulness, are found to explain 75% of the variance in the overall User Satisfaction measure. The empirical results also provide substantial support for the use of usefulness as an IS success measure, and of the hitherto-unreported importance of "Importance of the task" in user perceptions of IS usefulness.

  3. Impact of supplemental instruction leader on the success of supplemental instruction model

    Science.gov (United States)

    Mahabaduge, Hasitha; Haslam, Jeanne

    Supplemental instruction utilizes peer-assisted study sessions to provide review sessions on course material and an opportunity to discuss and work out problems. The impact of supplemental instruction on student performance is well researched and used in a large number of universities around the world due to its proven success. However, the impact of the student leader who plays a significant role in this model is rarely discussed in the literature. We present a case study on the impact of student leader on the success of supplemental instruction model. This case study was done for an Introductory Physics course correlating student performance and the supplemental instruction sessions they attended. Further analysis revealed that the academic performance and work ethics of the student leader has a significant impact on the success of the supplemental instruction model. Important factors to consider when selecting a student leader, the challenges and possible remedies will also be discussed.

  4. Examining the patterns and dynamics of species abundance distributions in succession of forest communities by model selection

    Science.gov (United States)

    Luo, Shao-Ming; Chen, Ping; He, Xiao; Guo, Wei; Li, Bailian

    2018-01-01

    the logCauchy model had the widest applicability in describing the SADs, and could best mirror the SAD patterns and dynamics of communities and their different layers in the succession of forests. The logCauchy-modeled SADs can quantitatively guide the construction of ecological forests and the restoration of degraded vegetation. PMID:29746516

  5. Information Systems Success In Public Administration: Proposal For An Exploratory Model

    Directory of Open Access Journals (Sweden)

    Deyvison de Lima Oliveira

    2015-12-01

    Full Text Available Investments in Information Systems (IS have been significantly increasing and hence the relevance of the studies on the IS success is persistent. Delone and Mclean (2003 developed an IS successful model which is a benchmark for researches in the area, however, in the perspective of the public sector, studies are still rare. In this research it was sought to propose an exploratory model of successful IS in public administration, from the identification of each construct items of the Delone and McLean (2003 original model, through multiple case studies in three Municipalities and a Town Hall of the Southern Cone of Rondônia state, in Brazil. Based on the empirical research, it was found that the IS success factors in municipal public administration are close to those factors indicated in the reviewed literature, however, showing some particularities of the public sector. A model of successful factors and items of IS, from the confrontation between literature and empirical data, is presented in the end of this work.

  6. Multi-state succession in wetlands: a novel use of state and transition models

    Science.gov (United States)

    Zweig, Christa L.; Kitchens, Wiley M.

    2009-01-01

    The complexity of ecosystems and mechanisms of succession are often simplified by linear and mathematical models used to understand and predict system behavior. Such models often do not incorporate multivariate, nonlinear feedbacks in pattern and process that include multiple scales of organization inherent within real-world systems. Wetlands are ecosystems with unique, nonlinear patterns of succession due to the regular, but often inconstant, presence of water on the landscape. We develop a general, nonspatial state and transition (S and T) succession conceptual model for wetlands and apply the general framework by creating annotated succession/management models and hypotheses for use in impact analysis on a portion of an imperiled wetland. The S and T models for our study area, Water Conservation Area 3A South (WCA3), Florida, USA, included hydrologic and peat depth values from multivariate analyses and classification and regression trees. We used the freeware Vegetation Dynamics Development Tool as an exploratory application to evaluate our S and T models with different management actions (equal chance [a control condition], deeper conditions, dry conditions, and increased hydrologic range) for three communities: slough, sawgrass (Cladium jamaicense), and wet prairie. Deeper conditions and increased hydrologic range behaved similarly, with the transition of community states to deeper states, particularly for sawgrass and slough. Hydrology is the primary mechanism for multi-state transitions within our study period, and we show both an immediate and lagged effect on vegetation, depending on community state. We consider these S and T succession models as a fraction of the framework for the Everglades. They are hypotheses for use in adaptive management, represent the community response to hydrology, and illustrate which aspects of hydrologic variability are important to community structure. We intend for these models to act as a foundation for further restoration

  7. Critical Factors Analysis for Offshore Software Development Success by Structural Equation Modeling

    Science.gov (United States)

    Wada, Yoshihisa; Tsuji, Hiroshi

    In order to analyze the success/failure factors in offshore software development service by the structural equation modeling, this paper proposes to follow two approaches together; domain knowledge based heuristic analysis and factor analysis based rational analysis. The former works for generating and verifying of hypothesis to find factors and causalities. The latter works for verifying factors introduced by theory to build the model without heuristics. Following the proposed combined approaches for the responses from skilled project managers of the questionnaire, this paper found that the vendor property has high causality for the success compared to software property and project property.

  8. Critical success factors model developing for sustainable Kaizen implementation in manufactur-ing industry in Ethiopia

    Directory of Open Access Journals (Sweden)

    Haftu Hailu

    2017-12-01

    Full Text Available The purpose of the research is to identify critical success factors and model developing for sustaining kaizen implementation. Peacock shoe is one of the manufacturing industries in Ethiopia facing challenges on sustaining. The methodology followed is factor analysis and empirically testing hypothesis. A database was designed using SPSS version 20. The survey was validated using statistical validation using the Cronbach alpha index; the result is 0.908. The KMO index value was obtained for the 32 items and had a value of 0.642 with Bartlett's Test of Sphericity Approx. Chi-Square 4503.007, degree of freedom 496 and significance value 0.000. A factor analysis by principal components and varimax rotation was applied for finding the critical success factors. Finding designates that 32 items were merged into eight critical success factors. All the eight factors together explain for 76.941 % of the variance. Multiple regression model analysis has indicated that some of the critical success factors had relationship with success indicators. Due to constraint of time, the researcher focused only at peacock shoe manufacturing industry. Other limitation also includes the absence of any local research that shows the critical success factors at the moment.

  9. Experienced Practitioners’ Beliefs Utilized to Create a Successful Massage Therapist Conceptual Model: a Qualitative Investigation

    Science.gov (United States)

    Kennedy, Anne B.; Munk, Niki

    2017-01-01

    Background The massage therapy profession in the United States has grown exponentially, with 35% of the profession’s practitioners in practice for three years or less. Investigating personal and social factors with regard to the massage therapy profession could help to identify constructs needed to be successful in the field. Purpose This data-gathering exercise explores massage therapists’ perceptions on what makes a successful massage therapist that will provide guidance for future research. Success is defined as supporting oneself and practice solely through massage therapy and related, revenue-generating field activity. Participants and Setting Ten successful massage therapy practitioners from around the United States who have a minimum of five years of experience. Research Design Semistructured qualitative interviews were used in an analytic induction framework; index cards with preidentified concepts printed on them were utilized to enhance conversation. An iterative process of interview coding and analysis was used to determine themes and subthemes. Results Based on the participants input, the categories in which therapists needed to be successful were organized into four main themes: effectively establish therapeutic relationships, develop massage therapy business acumen, seek valuable learning environments and opportunities, and cultivate strong social ties and networks. The four themes operate within specific contexts (e.g., regulation and licensing requirements in the therapists’ state), which may also influence the success of the massage therapist. Conclusions The model needs to be tested to explore which constructs explain variability in success and attrition rate. Limitations and future research implications are discussed. PMID:28690704

  10. Experienced Practitioners' Beliefs Utilized to Create a Successful Massage Therapist Conceptual Model: a Qualitative Investigation.

    Science.gov (United States)

    Kennedy, Anne B; Munk, Niki

    2017-06-01

    The massage therapy profession in the United States has grown exponentially, with 35% of the profession's practitioners in practice for three years or less. Investigating personal and social factors with regard to the massage therapy profession could help to identify constructs needed to be successful in the field. This data-gathering exercise explores massage therapists' perceptions on what makes a successful massage therapist that will provide guidance for future research. Success is defined as supporting oneself and practice solely through massage therapy and related, revenue-generating field activity. Ten successful massage therapy practitioners from around the United States who have a minimum of five years of experience. Semistructured qualitative interviews were used in an analytic induction framework; index cards with preidentified concepts printed on them were utilized to enhance conversation. An iterative process of interview coding and analysis was used to determine themes and subthemes. Based on the participants input, the categories in which therapists needed to be successful were organized into four main themes: effectively establish therapeutic relationships, develop massage therapy business acumen, seek valuable learning environments and opportunities, and cultivate strong social ties and networks. The four themes operate within specific contexts (e.g., regulation and licensing requirements in the therapists' state), which may also influence the success of the massage therapist. The model needs to be tested to explore which constructs explain variability in success and attrition rate. Limitations and future research implications are discussed.

  11. Success probability orientated optimization model for resource allocation of the technological innovation multi-project system

    Institute of Scientific and Technical Information of China (English)

    Weixu Dai; Weiwei Wu; Bo Yu; Yunhao Zhu

    2016-01-01

    A success probability orientated optimization model for resource al ocation of the technological innovation multi-project system is studied. Based on the definition of the technological in-novation multi-project system, the leveling optimization of cost and success probability is set as the objective of resource al ocation. The cost function and the probability function of the optimization model are constructed. Then the objective function of the model is constructed and the solving process is explained. The model is applied to the resource al ocation of an enterprise’s technological innovation multi-project system. The results show that the pro-posed model is more effective in rational resource al ocation, and is more applicable in maximizing the utility of the technological innovation multi-project system.

  12. Modelling the critical success factors of agile software development projects in South Africa

    Directory of Open Access Journals (Sweden)

    Tawanda B. Chiyangwa

    2017-10-01

    Full Text Available Background: The continued in failure of agile and traditional software development projects have led to the consideration, attention and dispute to critical success factors that are the aspects which are most vital to make a software engineering methodology fruitful. Although there is an increasing variety of critical success factors and methodologies, the conceptual frameworks which have causal relationship are limited. Objective: The objective of this study was to identify and provide insights into the critical success factors that influence the success of software development projects using agile methodologies in South Africa. Method: Quantitative method of collecting data was used. Data were collected in South Africa through a Web-based survey using structured questionnaires. Results: These results show that organisational factors have a great influence on performance expectancy characteristics. Conclusion: The results of this study discovered a comprehensive model that could provide guidelines to the agile community and to the agile professionals.

  13. Procedure to describe clavicular motion.

    Science.gov (United States)

    Gutierrez Delgado, Guivey; De Beule, Matthieu; Ortega Cardentey, Dolgis R; Segers, Patrick; Iznaga Benítez, Arsenio M; Rodríguez Moliner, Tania; Verhegghe, Benedict; Palmans, Tanneke; Van Hoof, Tom; Van Tongel, Alexander

    2017-03-01

    For many years, researchers have attempted to describe shoulder motions by using different mathematical methods. The aim of this study was to describe a procedure to quantify clavicular motion. The procedure proposed for the kinematic analysis consists of 4 main processes: 3 transcortical pins in the clavicle, motion capture, obtaining 3-dimensional bone models, and data processing. Clavicular motion by abduction (30° to 150°) and flexion (55° to 165°) were characterized by an increment of retraction of 27° to 33°, elevation of 25° to 28°, and posterior rotation of 14° to 15°, respectively. In circumduction, clavicular movement described an ellipse, which was reflected by retraction and elevation. Kinematic analysis shows that the articular surfaces move by simultaneously rolling and sliding on the convex surface of the sternum for the 3 movements of abduction, flexion, and circumduction. The use of 3 body landmarks in the clavicle and the direct measurement of bone allowed description of the osteokinematic and arthrokinematic movement of the clavicle. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  14. The effect of em>Hydrobia ulvaeem> and microphytobenthos on cohesive sediment dynamics on an intertidal mudflat described by means of numerical modelling

    DEFF Research Database (Denmark)

    Lumborg, Ulrik; Andersen, Thorbjørn Joest; Pejrup, Morten

    2006-01-01

    been used as input to the 2D hydrodynamic numerical model MIKE 21 MT. The model was used to investigate the effect that differences in the benthic communities may have on the net deposition. The model included computation of hydrodynamics, wave fields and cohesive sediment dynamics. Based...

  15. Information System Success Model for Customer Relationship Management System in Health Promotion Centers

    Science.gov (United States)

    Choi, Wona; Rho, Mi Jung; Park, Jiyun; Kim, Kwang-Jum; Kwon, Young Dae

    2013-01-01

    Objectives Intensified competitiveness in the healthcare industry has increased the number of healthcare centers and propelled the introduction of customer relationship management (CRM) systems to meet diverse customer demands. This study aimed to develop the information system success model of the CRM system by investigating previously proposed indicators within the model. Methods The evaluation areas of the CRM system includes three areas: the system characteristics area (system quality, information quality, and service quality), the user area (perceived usefulness and user satisfaction), and the performance area (personal performance and organizational performance). Detailed evaluation criteria of the three areas were developed, and its validity was verified by a survey administered to CRM system users in 13 nationwide health promotion centers. The survey data were analyzed by the structural equation modeling method, and the results confirmed that the model is feasible. Results Information quality and service quality showed a statistically significant relationship with perceived usefulness and user satisfaction. Consequently, the perceived usefulness and user satisfaction had significant influence on individual performance as well as an indirect influence on organizational performance. Conclusions This study extends the research area on information success from general information systems to CRM systems in health promotion centers applying a previous information success model. This lays a foundation for evaluating health promotion center systems and provides a useful guide for successful implementation of hospital CRM systems. PMID:23882416

  16. Information system success model for customer relationship management system in health promotion centers.

    Science.gov (United States)

    Choi, Wona; Rho, Mi Jung; Park, Jiyun; Kim, Kwang-Jum; Kwon, Young Dae; Choi, In Young

    2013-06-01

    Intensified competitiveness in the healthcare industry has increased the number of healthcare centers and propelled the introduction of customer relationship management (CRM) systems to meet diverse customer demands. This study aimed to develop the information system success model of the CRM system by investigating previously proposed indicators within the model. THE EVALUATION AREAS OF THE CRM SYSTEM INCLUDES THREE AREAS: the system characteristics area (system quality, information quality, and service quality), the user area (perceived usefulness and user satisfaction), and the performance area (personal performance and organizational performance). Detailed evaluation criteria of the three areas were developed, and its validity was verified by a survey administered to CRM system users in 13 nationwide health promotion centers. The survey data were analyzed by the structural equation modeling method, and the results confirmed that the model is feasible. Information quality and service quality showed a statistically significant relationship with perceived usefulness and user satisfaction. Consequently, the perceived usefulness and user satisfaction had significant influence on individual performance as well as an indirect influence on organizational performance. This study extends the research area on information success from general information systems to CRM systems in health promotion centers applying a previous information success model. This lays a foundation for evaluating health promotion center systems and provides a useful guide for successful implementation of hospital CRM systems.

  17. Promoting success or preventing failure: cultural differences in motivation by positive and negative role models.

    Science.gov (United States)

    Lockwood, Penelope; Marshall, Tara C; Sadler, Pamela

    2005-03-01

    In two studies, cross-cultural differences in reactions to positive and negative role models were examined. The authors predicted that individuals from collectivistic cultures, who have a stronger prevention orientation, would be most motivated by negative role models, who highlight a strategy of avoiding failure; individuals from individualistic cultures, who have a stronger promotion focus, would be most motivated by positive role models, who highlight a strategy of pursuing success. In Study 1, the authors examined participants' reported preferences for positive and negative role models. Asian Canadian participants reported finding negative models more motivating than did European Canadians; self-construals and regulatory focus mediated cultural differences in reactions to role models. In Study 2, the authors examined the impact of role models on the academic motivation of Asian Canadian and European Canadian participants. Asian Canadians were motivated only by a negative model, and European Canadians were motivated only by a positive model.

  18. An internally validated prognostic model for success in revision stapes surgery for otosclerosis.

    Science.gov (United States)

    Wegner, Inge; Vincent, Robert; Derks, Laura S M; Rauh, Simone P; Heymans, Martijn W; Stegeman, Inge; Grolman, Wilko

    2018-03-09

    To develop a prediction model that can accurately predict the chance of success following revision stapes surgery in patients with recurrent or persistent otosclerosis at 2- to 6-months follow-up and to validate this model internally. A retrospective cohort study of prospectively gathered data in a tertiary referral center. The associations of 11 prognostic factors with treatment success were tested in 705 cases using multivariable logistic regression analysis with backward selection. Success was defined as a mean air-bone gap closure to 10 dB or less. The most relevant predictors were used to derive a clinical prediction rule to determine the probability of success. Internal validation by means of bootstrapping was performed. Model performance indices, including the Hosmer-Lemeshow test, the area under the receiver operating characteristics curve (AUC), and the explained variance were calculated. Success was achieved in 57.7% of cases at 2- to 6-months follow-up. Certain previous surgical techniques, primary causes of failure leading up to revision stapes surgery, and positions of the prosthesis placed during revision surgery were associated with higher success percentages. The clinical prediction rule performed moderately well in the original dataset (Hosmer-Lemeshow P = .78; AUC = 0.73; explained variance = 22%), which slightly decreased following internal validation by means of bootstrapping (AUC = 0.69; explained variance = 13%). Our study established the importance of previous surgical technique, primary cause of failure, and type of the prosthesis placed during the revision surgery in predicting the probability of success following stapes surgery at 2- to 6-months follow-up. 2b. Laryngoscope, 2018. © 2018 The American Laryngological, Rhinological and Otological Society, Inc.

  19. Modelling cheetah relocation success in southern Africa using an iterative Bayesian network development cycle

    CSIR Research Space (South Africa)

    Johnson, S

    2010-02-01

    Full Text Available metapopulations was the focus of a Bayesian Network (BN) modelling workshop in South Africa. Using a new heuristics, Iterative Bayesian Network Development Cycle (IBNDC), described in this paper, several networks were formulated to distinguish between the unique...

  20. [Succession caused by beaver (Castor fiber L.) life activity: II. A refined Markov model].

    Science.gov (United States)

    Logofet; Evstigneev, O I; Aleinikov, A A; Morozova, A O

    2015-01-01

    The refined Markov model of cyclic zoogenic successions caused by beaver (Castor fiber L.) life activity represents a discrete chain of the following six states: flooded forest, swamped forest, pond, grassy swamp, shrubby swamp, and wet forest, which correspond to certain stages of succession. Those stages are defined, and a conceptual scheme of probable transitions between them for one time step is constructed from the knowledge of beaver behaviour in small river floodplains of "Bryanskii Les" Reserve. We calibrated the corresponding matrix of transition probabilities according to the optimization principle: minimizing differences between the model outcome and reality; the model generates a distribution of relative areas corresponding to the stages of succession, that has to be compared to those gained from case studies in the Reserve during 2002-2006. The time step is chosen to equal 2 years, and the first-step data in the sum of differences are given various weights, w (between 0 and 1). The value of w = 0.2 is selected due to its optimality and for some additional reasons. By the formulae of finite homogeneous Markov chain theory, we obtained the main results of the calibrated model, namely, a steady-state distribution of stage areas, indexes of cyclicity, and the mean durations (M(j)) of succession stages. The results of calibration give an objective quantitative nature to the expert knowledge of the course of succession and get a proper interpretation. The 2010 data, which are not involved in the calibration procedure, enabled assessing the quality of prediction by the homogeneous model in short-term (from the 2006 situation): the error of model area distribution relative to the distribution observed in 2010 falls into the range of 9-17%, the best prognosis being given by the least optimal matrices (rejected values of w). This indicates a formally heterogeneous nature of succession processes in time. Thus, the refined version of the homogeneous Markov chain

  1. The Achieving Success Everyday Group Counseling Model: Fostering Resiliency in Middle School Students

    Science.gov (United States)

    Rose, Joy; Steen, Sam

    2015-01-01

    This article discusses a group counseling intervention used to develop and foster resiliency in middle school students by implementing the Achieving Success Everyday (ASE) group counseling model. The authors aimed to discover what impact this group counseling intervention, which focused on resiliency characteristics, would have on students'…

  2. The Effect of 7E Model on Conceptual Success of Students in the Unit of Electromagnetism

    Science.gov (United States)

    Turgut, Umit; Colak, Alp; Salar, Riza

    2016-01-01

    The aim of this study was to investigate the impact of the course materials developed in accordance with 7E model in the unit of electromagnetism in high school physics class on students' conceptual success. The present study was conducted with a total of 52 11th grade students in two separate classrooms at a high school. The action research…

  3. Modelling the Success of Learning Management Systems: Application of Latent Class Segmentation Using FIMIX-PLS

    Science.gov (United States)

    Arenas-Gaitán, Jorge; Rondán-Cataluña, Francisco Javier; Ramírez-Correa, Patricio E.

    2018-01-01

    There is not a unique attitude towards the implementation of digital technology in educational sceneries. This paper aims to validate an adaptation of the DeLone and McLean information systems success model in the context of a learning management system. Furthermore, this study means to prove (1) the necessity of segmenting students in order to…

  4. Developing a Model and Applications for Probabilities of Student Success: A Case Study of Predictive Analytics

    Science.gov (United States)

    Calvert, Carol Elaine

    2014-01-01

    This case study relates to distance learning students on open access courses. It demonstrates the use of predictive analytics to generate a model of the probabilities of success and retention at different points, or milestones, in a student journey. A core set of explanatory variables has been established and their varying relative importance at…

  5. 25-years three-fluid modeling-experience: successes and limits

    International Nuclear Information System (INIS)

    Kolev, N.I.

    2004-01-01

    The paper presents many examples of successful use of the three fluid processes modeling in 1D-networks, 3D-single volumes and 3D-boundary fitted volumes in the nuclear engineering. Fig. 1 shows 2700K hot molten aluminum oxide dropped in water and 3000K uranium oxide dropped in water as a demonstration for mathematical modeling of very complex real processes. (author)

  6. Model of Islamic Social Entrepreneurship: A Study on Successful Muslim Social Entrepreneur in Malaysia

    OpenAIRE

    Boulven Mohd Adib; Abdullah S.; Bahari Azizan; Ramli A. J.; Hussin N. S.; Jamaluddin Jamsari; Ahmad Z.

    2018-01-01

    Since research effort in the area is minimal, there is a clear need to examine the practice of Islamic social entrepreneurship among successful Muslim social entrepreneurs in Malaysia. One such practice is to organize charitable activities to benefit the community through the gains made from entrepreneurial activities that are based on social mission and vision. The research problem is lacking of model on Islamic social entrepreneurship. The main objective of this paper is to develop a Model ...

  7. Developments to the Sylvan stand structure model to describe wood quality changes in southern bottomland hardwood forests because of forest management

    Science.gov (United States)

    Ian R. Scott

    2009-01-01

    Growth models can produce a wealth of detailed information that is often very difficult to perceive because it is frequently presented either as summary tables, stand view or landscape view visualizations. We have developed new tools for use with the Sylvan model (Larsen 1994) that allow the analysis of wood-quality changes as a consequence of forest management....

  8. Sensitivity analysis of a radionuclide transfer model describing contaminated vegetation in Fukushima prefecture, using Morris and Sobol' - Application of sensitivity analysis on a radionuclides transfer model in the environment describing weeds contamination in Fukushima Prefecture, using Morris method and Sobol' indices indices

    Energy Technology Data Exchange (ETDEWEB)

    Nicoulaud-Gouin, V.; Metivier, J.M.; Gonze, M.A. [Institut de Radioprotection et de Surete Nucleaire-PRP-ENV/SERIS/LM2E (France); Garcia-Sanchez, L. [Institut de Radioprotection et de Surete Nucleaire-PRPENV/SERIS/L2BT (France)

    2014-07-01

    The increasing spatial and temporal complexity of models demands methods capable of ranking the influence of their large numbers of parameters. This question specifically arises in assessment studies on the consequences of the Fukushima accident. Sensitivity analysis aims at measuring the influence of input variability on the output response. Generally, two main approaches are distinguished (Saltelli, 2001, Iooss, 2011): - Screening approach, less expensive in computation time and allowing to identify non influential parameters; - Measures of importance, introducing finer quantitative indices. In this category, there are regression-based methods, assuming a linear or monotonic response (Pearson coefficient, Spearman coefficient), and variance-based methods, without assumptions on the model but requiring an increasingly prohibitive number of evaluations when the number of parameters increases. These approaches are available in various statistical programs (notably R) but are still poorly integrated in modelling platforms of radioecological risk assessment. This work aimed at illustrating the benefits of sensitivity analysis in the course of radioecological risk assessments This study used two complementary state-of-art global sensitivity analysis methods: - The screening method of Morris (Morris, 1991; Campolongo et al., 2007) based on limited model evaluations with a one-at-a-time (OAT) design; - The variance-based Sobol' sensitivity analysis (Saltelli, 2002) based a large number of model evaluations in the parameter space with a quasi-random sampling (Owen, 2003). Sensitivity analyses were applied on a dynamic Soil-Plant Deposition Model (Gonze et al., submitted to this conference) predicting foliar concentration in weeds after atmospheric radionuclide fallout. The Soil-Plant Deposition Model considers two foliage pools and a root pool, and describes foliar biomass growth with a Verhulst model. The developed semi-analytic formulation of foliar concentration

  9. Maximum Potential Score (MPS: An operating model for a successful customer-focused strategy.

    Directory of Open Access Journals (Sweden)

    Cabello González, José Manuel

    2015-12-01

    Full Text Available One of marketers’ chief objectives is to achieve customer loyalty, which is a key factor for profitable growth. Therefore, they need to develop a strategy that attracts and maintains customers, giving them adequate motives, both tangible (prices and promotions and intangible (personalized service and treatment, to satisfy a customer and make him loyal to the company. Finding a way to accurately measure satisfaction and customer loyalty is very important. With regard to typical Relationship Marketing measures, we can consider listening to customers, which can help to achieve a competitive sustainable advantage. Customer satisfaction surveys are essential tools for listening to customers. Short questionnaires have gained considerable acceptance among marketers as a means to achieve a customer satisfaction measure. Our research provides an indication of the benefits of a short questionnaire (one/three questions. We find that the number of questions survey is significantly related to the participation in the survey (Net Promoter Score or NPS. We also prove that a the three question survey is more likely to have more participants than a traditional survey (Maximum Potential Score or MPS . Our main goal is to analyse one method as a potential predictor of customer loyalty. Using surveys, we attempt to empirically establish the causal factors in determining the satisfaction of customers. This paper describes a maximum potential operating model that captures with a three questions survey, important elements for a successful customer-focused strategy. MPS may give us lower participation rates than NPS but important information that helps to convert unhappy customers or just satisfied customers, into loyal customers.

  10. A comparison of Reduced Life Expectancy (RLE) model with Haber's Rule to describe effects of exposure time on toxicity

    International Nuclear Information System (INIS)

    Verma, Vibha; Yu, Qiming J.; Connell, Des W.

    2015-01-01

    The Reduced Life Expectancy (RLE) Model (LC 50  = [ln(NLE) – ln(LT 50 )]/d) has been proposed as an alternative to Haber's Rule. The model is based on a linear relationship between LC 50 (Lethal Exposure Concentration) and lnLT 50 (Lethal Exposure Time) and uses NLE (Normal Life Expectancy) as a limiting point as well as a long term data point (where d is a constant). The purposes of this paper were to compare the RLE Model with Haber's Rule with available toxicity data and to evaluate the strengths and weaknesses of each approach. When LT 50 is relatively short and LC 50 is high, Haber's Rule is consistent with the RLE model. But the difference between the two was evident in the situation when LT 50 is relatively long and LC 50 is low where the RLE model is a marked departure from Haber's Rule. The RLE Model can be used to appropriately evaluate long term effects of exposure. - Highlights: • The strength and weakness of Haber's Rule in relation to the RLE model is needed. • Haber's Rule now used universally is quite inappropriate for environmental toxicity. • Normal life expectancy, a new parameter l is used to evaluate effects of exposure time on toxicity. • According to RLE model when LC 50 approaches zero, then LT 50  = Normal Life Expectancy. • The RLE model can be used to evaluate long term effects of exposure-accurately and easily. - The RLE approach is a more appropriate alternative particularly to evaluate long term effects of exposure. It can be easily used to estimate long term effects of exposure

  11. Incorporating the user perspective into a proposed model for assessing success of SHS implementations

    Directory of Open Access Journals (Sweden)

    Hans Holtorf

    2015-10-01

    Full Text Available Modern energy can contribute to development in multiple ways while approximately 20% of world's populations do not yet have access to electricity. Solar Home Systems (SHSs consists of a PV module, a charge controller and a battery supply in the range of 100 Wh/d in Sunbelt countries. The question addressed in this paper is how SHS users approach success of their systems and how these user's views can be integrated in to an existing model of success. Information was obtained on the user's approach to their SHSs by participatory observation, interviews with users and by self-observation undertaken by the lead author while residing under SHS electricity supply conditions. It was found that success of SHSs from the users' point of view is related to the ability of these systems to reduce the burdens of supplying energy services to homesteads. SHSs can alleviate some energy supply burdens, and they can improve living conditions by enabling communication on multiple levels and by addressing convenience and safety concerns. However, SHSs do not contribute to the energy services which are indispensable for survival, nor to the thermal energy services required and desired in dwellings of Sunbelt countries. The elements of three of the four components of our previously proposed model of success have been verified and found to be appropriate, namely the user's self-set goals, their importance and SHSs' success factors. The locally appropriate, and scientifically satisfactory, measurement of the level of achievement of self-set goals, the fourth component of our model of success, remains an interesting area for future research.

  12. A Primary Human Critical Success Factors Model for the ERP System Implementation

    Directory of Open Access Journals (Sweden)

    Jenko Aleksander

    2016-08-01

    Full Text Available Background and Purpose: Many researchers have investigated various Critical success factors (CSFs and the different causes of ERP implementation project failures. Despite a detailed literature preview, we were unable to find an appropriate research with a comprehensive overview of the true causes behind CSFs, observed from a human factors perspective. The objective of this research was therefore to develop and evaluate the Primary human factors (PHFs model and to confirm the significant impact of PHFs on traditional CSFs and on the project success.

  13. Successful completion of the Qinshan phase III nuclear power plant-a successful model for Chinese-Canadian cooperation

    International Nuclear Information System (INIS)

    Peng Xiaoxing

    2004-01-01

    This report documents Qinshan CANDU project construction and commissioning experience as well as management strategies and approaches that contributed to the successful completion of the project. The Qinshan phase III (CANDU) nuclear power plant was built in record times: Unit 1 achieved commercial operation on December 31, 2002 and Unit 2 on July 24, 2003, 43 days and 112 days ahead of schedule respectively. The reference plant design is the Wolsong 3 and 4 CANDU-6 units in the Republic of Korea. Improvements in design and construction methods allowed Unit 1 to be constructed in 51.5 Months from First Concrete to Criticality-a record in China for nuclear power plants. The key factors are project management and project management tools, quality assurance, construction methods (including open top construction, heavy lifts and modularization), electronic documentation with configuration control that provides up-to-date on-line information, CADDS design linked with material management, specialized material control including bar coding, and planning. The introduction of new design and construction techniques was achieved by combining conventional AECL practices with working experiences in China. The most advanced tools and techniques for achieving optimum construction quality, schedule and cost were used. Successful application of advanced project management methods and tools will benefit TQNPC in operation of the station, and the Chinese contractors in advancing their capabilities in future nuclear projects in China and enhancing their opportunities internationally. TQNPC's participation in Quality surveillance (QS) activities of nuclear steam plant (NSP) and Balance of Plant (BOP) offshore equipment benefited TQNPC in acquiring knowledge of specific equipment manufacturing processes, which can be applied to similar activities in China. China has established the capability of manufacturing CANDU fuel and becoming self-reliant in fuel supply. Excellent co-operation and

  14. The SUCCESS model for laboratory performance and execution of rapid molecular diagnostics in patients with sepsis.

    Science.gov (United States)

    Dekmezian, Mhair; Beal, Stacy G; Damashek, Mary Jane; Benavides, Raul; Dhiman, Neelam

    2015-04-01

    Successful performance and execution of rapid diagnostics in a clinical laboratory hinges heavily on careful validation, accurate and timely communication of results, and real-time quality monitoring. Laboratories must develop strategies to integrate diagnostics with stewardship and evidence-based clinical practice guidelines. We present a collaborative SUCCESS model for execution and monitoring of rapid sepsis diagnostics to facilitate timely treatment. Six months after execution of the Verigene Gram-Positive Blood Culture (BC-GP) and the AdvanDx PNA-FISH assays, data were collected on 579 and 28 episodes of bacteremia and fungemia, respectively. Clinical testing was executed using a SUCCESS model comprising the following components: stewardship, utilization of resources, core strategies, concierge services, education, support, and surveillance. Stewardship needs were identified by evaluating the specialty services benefiting from new testing. Utilization of resources was optimized by reviewing current treatment strategies and antibiogram and formulary options. Core strategies consisted of input from infectious disease leadership, pharmacy, and laboratory staff. Concierge services included automated Micro-eUpdate and physician-friendly actionable reports. Education modules were user-specific, and support was provided through a dedicated 24/7 microbiology hotline. Surveillance was performed by daily audit by the director. Using the SUCCESS model, the turnaround time for the detailed report with actionable guidelines to the physician was ∼3 hours from the time of culture positivity. The overall correlation between rapid methods and culture was 94% (546/579). Discrepant results were predominantly contaminants such as a coagulase-negative staphylococci or viridans streptococci in mixed cultures. SUCCESS is a cost-effective and easily adaptable model for clinical laboratories with limited stewardship resources.

  15. Experimental and numerical investigations to describe the failure behaviour of steels of different toughness by means of damage models. Final report

    International Nuclear Information System (INIS)

    Kussmaul, K.; Seidenfuss, M.; Elsaesser, K.; Mayer, U.; Zies, G.

    1995-08-01

    Within the scope of the project the applicability of local approach models to different steels in reactor technology was investigated. To this two ferritic and one austenitic material were investigated. The metallographic investigations carried out in this project prove the fact that the fracture development of the three investigated materials can be divided in three phases: Void initiation, void growth, and void coalescence. The focus of the research project was to determine the parameters required for the local approach models if possible with the help of metallographic investigations. In order to obtain quantitative results with realistic expenditure an automatic imagine evaluation system was adapted. In the course of the project it could be found that two out of the maximum six damage parameters of the Rousselier model were constant for all three materials. There is an indication that these two parameters are independent of the material and can generally be assumed as constant. The investigations have proved that the selected local approach models are adequate for calculating the failure behaviour of smooth, notched and precracked specimens under static load. The parameters required for the damage models are independent of geometry and size, and so a transferability of the parameters is possible. (orig./MM) [de

  16. A practice model for rural district nursing success in end-of-life advocacy care.

    Science.gov (United States)

    Reed, Frances M; Fitzgerald, Les; Bish, Melanie R

    2017-08-24

    The development of a practice model for rural district nursing successful end-of-life advocacy care. Resources to help people live well in the end stages of life in rural areas can be limited and difficult to access. District nurse advocacy may promote end-of-life choice for people living at home in rural Australia. The lack of evidence available internationally to inform practice in this context was addressed by exploratory study. A pragmatic mixed method study approved by the University Faculty Ethics Committee and conducted from March 2014 to August 2015 was used to explore the successful end-of-life advocacy of 98 rural Australian district nurses. The findings and results were integrated then compared with theory in this article to develop concepts for a practice model. The model illustrates rural district nurse advocacy success based on respect for the rights and values of people. Advocacy action is motivated by the emotional responses of nurses to the end-of-life vulnerability people experience. The combination of willing investment in relationships, knowing the rural people and resources, and feeling supported, together enables district nurses to develop therapeutic emotional intelligence. This skill promotes moral agency in reflection and advocacy action to overcome emotional and ethical care challenges of access and choice using holistic assessment, communication, organisation of resources and empowering support for the self-determination of person-centred end-of-life goals. Recommendations are proposed from the theoretical concepts in the model. Testing the model in practice is recommended to gain the perceptions of a broader range of rural people both giving and receiving end-of-life-care. A model developed by gathering and comparing district nursing experiences and understanding using mixed methods and existing theory offers evidence for practice of a philosophy of successful person-centred advocacy care in a field of nursing that lacks specific

  17. Describing Compton scattering and two-quanta positron annihilation based on Compton profiles: Two models suited for the Monte Carlo method

    CERN Document Server

    Bohlen, TT; Patera, V; Sala, P R

    2012-01-01

    An accurate description of the basic physics processes of Compton scattering and positron annihilation in matter requires the consideration of atomic shell structure effects and, in specific, the momentum distributions of the atomic electrons. Two algorithms which model Compton scattering and two-quanta positron annihilation at rest accounting for shell structure effects are proposed. Two-quanta positron annihilation is a physics process which is of particular importance for applications such as positron emission tomography (PET). Both models use a detailed description of the processes which incorporate consistently Doppler broadening and binding effects. This together with the relatively low level of complexity of the models makes them particularly suited to be employed by fast sampling methods for Monte Carlo particle transport. Momentum distributions of shell electrons are obtained from parametrized one-electron Compton profiles. For conduction electrons, momentum distributions are derived in the framework...

  18. A model to describe the surface gradient-nanograin formation and property of friction stir processed laser Co-Cr-Ni-Mo alloy

    Science.gov (United States)

    Li, Ruidi; Yuan, Tiechui; Qiu, Zili

    2014-07-01

    A gradient-nanograin surface layer of Co-base alloy was prepared by friction stir processing (FSP) of laser-clad coating in this work. However, it is lack of a quantitatively function relationship between grain refinement and FSP conditions. Based on this, an analytic model is derived for the correlations between carbide size, hardness and rotary speed, layer depth during in-situ FSP of laser-clad Co-Cr-Ni-Mo alloy. The model is based on the principle of typical plastic flow in friction welding and dynamic recrystallization. The FSP experiment for modification of laser-clad Co-based alloy was conducted and its gradient nanograin and hardness were characterized. It shows that the model is consistent with experimental results.

  19. Linear mixed-effects models to describe length-weight relationships for yellow croaker (Larimichthys Polyactis) along the north coast of China.

    Science.gov (United States)

    Ma, Qiuyun; Jiao, Yan; Ren, Yiping

    2017-01-01

    In this study, length-weight relationships and relative condition factors were analyzed for Yellow Croaker (Larimichthys polyactis) along the north coast of China. Data covered six regions from north to south: Yellow River Estuary, Coastal Waters of Northern Shandong, Jiaozhou Bay, Coastal Waters of Qingdao, Haizhou Bay, and South Yellow Sea. In total 3,275 individuals were collected during six years (2008, 2011-2015). One generalized linear model, two simply linear models and nine linear mixed effect models that applied the effects from regions and/or years to coefficient a and/or the exponent b were studied and compared. Among these twelve models, the linear mixed effect model with random effects from both regions and years fit the data best, with lowest Akaike information criterion value and mean absolute error. In this model, the estimated a was 0.0192, with 95% confidence interval 0.0178~0.0308, and the estimated exponent b was 2.917 with 95% confidence interval 2.731~2.945. Estimates for a and b with the random effects in intercept and coefficient from Region and Year, ranged from 0.013 to 0.023 and from 2.835 to 3.017, respectively. Both regions and years had effects on parameters a and b, while the effects from years were shown to be much larger than those from regions. Except for Coastal Waters of Northern Shandong, a decreased from north to south. Condition factors relative to reference years of 1960, 1986, 2005, 2007, 2008~2009 and 2010 revealed that the body shape of Yellow Croaker became thinner in recent years. Furthermore relative condition factors varied among months, years, regions and length. The values of a and relative condition factors decreased, when the environmental pollution became worse, therefore, length-weight relationships could be an indicator for the environment quality. Results from this study provided basic description of current condition of Yellow Croaker along the north coast of China.

  20. A model of the FAD redox cycle describes the dynamics of the effect of the geomagnetic field on the human visual system.

    Science.gov (United States)

    Thoss, Franz; Bartsch, Bengt

    2017-12-01

    In experimental studies, we could show that the visual threshold of man is influenced by the geomagnetic field. One of the results was that the threshold shows periodic fluctuations when the vertical component of the field is reversed periodically. The maximum of these oscillations occurred at a period duration of 110 s. To explain this phenomenon, we chose the process that likely underlies the navigation of birds in the geomagnetic field: the light reaction of the FAD component of cryptochrome in the retina. The human retina contains cryptpochrome like the bird retina. Based on the investigations of Müller and Ahmad (J Biol Chem 286:21033-21040, 2011) and Solov'yov and Schulten (J Phys Chem B 116:1089-1099, 2012), we designed a model of the light-induced reduction and subsequent reoxidation of FAD. This model contains a radical pair, whose interconversion dynamics are affected by the geomagnetic field. The parameters of the model were partly calculated from the data of our experimental investigation and partly taken from the results of other authors. These parameters were then optimized by adjusting the model behaviour to the experimental results. The simulation of the finished model shows that the concentrations of all substances included show really oscillations with the frequency of the modelled magnetic field. After optimization of the parameters, the oscillations of FAD and FADH* show maximal amplitude at a period duration of 110 s, as was observed in the experiment. This makes it most likely that the signal, which influences the visual system, originates from FADH* (signalling state).

  1. Model for assessing the success of SMEs in the internacionali­zation process

    Directory of Open Access Journals (Sweden)

    Lea Kubíčková

    2010-01-01

    Full Text Available The paper deals with evaluating the success of small and medium-sized companies in in­ter­na­tio­na­li­za­tion process. The process of internationalization is defined in the literature in a many ways; there is a countless variety of different approaches and models of internationalization process of firms. Like all processes in the firm also the internationalization process is accompanied by risks. For risk management it is important to know what the key factors of success are in the international arena. In this article is presented a simple evaluation model that could be used by SMEs to determine not only how strong are they compared to competitors, but also at what level are their key success factors in the process of internationalization. The aim was to find a simple method to help small and medium enterprises to assess their situation in the field of internationalization and to help them identify their strengths and weaknesses in this area. Proposed simple evaluation model has the graphic output from which it can be seen in which areas the company is doing well in internationalization process and in what areas is doing badly – then there is room for further improvement. Creating the model it was essential to divide the various factors into several groups and further evaluation to determine the range by which SMEs can quantify the level of success in internationalization process. Before the model was constructed it was necessary to collect data among small and mid-sized firms, and to process the outputs of the survey. After confirmation or to rejection of the certain hypotheses key success factors of SMEs in the internationalization process were selected and these factors were then aggregated into 4 groups. The model was then applied to data obtained from a survey of 40 SMEs and in the paper there are presented specific examples of graphical output of the model for the best and worst rated company. Authors are aware that the model is

  2. Modelling the attack success of planktonic predators: patterns and mechanisms of prey size selectivity

    DEFF Research Database (Denmark)

    Caparroy, P.; Thygesen, Uffe Høgsbro; Visser, Andre

    2000-01-01

    of being captured. By combining the attack success model with previously published hydrodynamic models of predator and prey perception, we examine how predator foraging behaviour and prey perceptive ability affect the size spectra of encountered and captured copepod prey. We examine food size spectra of (i......) a rheotactic cruising predator, (ii) a suspension-feeding hovering copepod and (iii) a larval fish. For rheotactic predators such as carnivorous copepods, a central assumption of the model is that attack is triggered by prey escape reaction, which in turn depends on the deformation rate of the fluid created...

  3. A successful model for longitudinal community-engaged health research: the 2040 Partners for Health Student Program.

    Science.gov (United States)

    Redman, Romany M; Reinsvold, Magdalena C; Reddy, Anireddy; Bennett, Paige E; Hoerauf, Janine M; Puls, Kristina M; Ovrutsky, Alida R; Ly, Alexandra R; White, Gregory; McNeil, Owetta; Meredith, Janet J

    2017-06-01

    Community-based participatory research [CBPR] is an emerging approach to collaborative research aimed at creating locally effective and sustainable interventions. The 2040 Partners for Health student program was developed as a unique model of longitudinal CBPR. Analysis of this program and its components illuminates both the challenges and the opportunities inherent in community engagement. The program rests on a foundation of a community-based, non-profit organization and a supportive academic university centre. Inter-professional health students and community members of underserved populations work together on different health projects by employing an adapted CBPR methodology. Three successful examples of sustainable CBPR projects are briefly described. The three projects are presented as primary outcomes resulting from this model. Benefits and challenges of the model as an approach to community-engaged research are discussed as well as secondary benefits of student participation. The 2040 Partners for Health student program represents a successful model of CBPR, illuminating common challenges and reiterating the profound value of community-engaged research. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Validation of the DeLone and McLean Information Systems Success Model.

    Science.gov (United States)

    Ojo, Adebowale I

    2017-01-01

    This study is an adaptation of the widely used DeLone and McLean information system success model in the context of hospital information systems in a developing country. A survey research design was adopted in the study. A structured questionnaire was used to collect data from 442 health information management personnel in five Nigerian teaching hospitals. A structural equation modeling technique was used to validate the model's constructs. It was revealed that system quality significantly influenced use (β = 0.53, p Information quality significantly influenced use (β = 0.24, p 0.05), but it significantly influenced perceived net benefits (β = 0.21, p 0.05). The study validates the DeLone and McLean information system success model in the context of a hospital information system in a developing country. Importantly, system quality and use were found to be important measures of hospital information system success. It is, therefore, imperative that hospital information systems are designed in such ways that are easy to use, flexible, and functional to serve their purpose.

  5. A structural equation model to integrate changes in functional strategies during old-field succession.

    Science.gov (United States)

    Vile, Denis; Shipley, Bill; Garnier, Eric

    2006-02-01

    From a functional perspective, changes in abundance, and ultimately species replacement, during succession are a consequence of integrated suites of traits conferring different relative ecological advantages as the environment changes over time. Here we use structural equations to model the interspecific relationships between these integrated functional traits using 34 herbaceous species from a Mediterranean old-field succession and thus quantify the notion of a plant strategy. We measured plant traits related to plant vegetative and reproductive size, leaf functioning, reproductive phenology, seed mass, and production on 15 individuals per species monitored during one growing season. The resulting structural equation model successfully accounts for the pattern of trait covariation during the first 45 years post-abandonment using just two forcing variables: time since site abandonment and seed mass; no association between time since field abandonment and seed mass was observed over these herbaceous stages of secondary succession. All other predicted traits values are determined by these two variables and the cause-effect linkage between them. Adding pre-reproductive vegetative mass as a third forcing variable noticeably increased the predictive power of the model. Increasing the time after abandonment favors species with increasing life span and pre-reproductive biomass and decreasing specific leaf area. Allometric coefficients relating vegetative and reproductive components of plant size were in accordance with allometry theory. The model confirmed the trade-off between seed mass and seed number. Maximum plant height and seed mass were major determinants of reproductive phenology. Our results show that beyond verbal conceptualization, plant ecological strategies can be quantified and modeled.

  6. Exhaustive Classification of the Invariant Solutions for a Specific Nonlinear Model Describing Near Planar and Marginally Long-Wave Unstable Interfaces for Phase Transition

    Science.gov (United States)

    Ahangari, Fatemeh

    2018-05-01

    Problems of thermodynamic phase transition originate inherently in solidification, combustion and various other significant fields. If the transition region among two locally stable phases is adequately narrow, the dynamics can be modeled by an interface motion. This paper is devoted to exhaustive analysis of the invariant solutions for a modified Kuramoto-Sivashinsky equation in two spatial and one temporal dimensions is presented. This nonlinear partial differential equation asymptotically characterizes near planar interfaces, which are marginally long-wave unstable. For this purpose, by applying the classical symmetry method for this model the classical symmetry operators are attained. Moreover, the structure of the Lie algebra of symmetries is discussed and the optimal system of subalgebras, which yields the preliminary classification of group invariant solutions is constructed. Mainly, the Lie invariants corresponding to the infinitesimal symmetry generators as well as associated similarity reduced equations are also pointed out. Furthermore, the nonclassical symmetries of this nonlinear PDE are also comprehensively investigated.

  7. Experimental Verification of a New Model Describing the Influence of Incomplete Signal Extinction Ratio on the Sensitivity Degradation due to Multiple Interferometric Crosstalk

    DEFF Research Database (Denmark)

    Liu, Fenghai; Rasmussen, Christian Jørgen; Pedersen, Rune Johan Skullerud

    1999-01-01

    Larger optical penalties than predicted by a Gaussian crosstalk model are found both in our experiments and in the literature when investigating signals including multiple interferometric crosstalk contributions. We attribute this to an imperfect signal extinction ratio. In this letter, simple...... analytical relations for crosstalk induced power penalties are derived taking the signal extinction ratio into account and excellent agreement with 10-Gb/s experiments is obtained. Both theory and experiment show the importance of the signal extinction ratio in connection with interferometric crosstalk....

  8. Is the fluid mosaic (and the accompanying raft hypothesis a suitable model to describe fundamental features of biological membranes? What may be missing?

    Directory of Open Access Journals (Sweden)

    Luis Alberto Bagatolli

    2013-11-01

    Full Text Available The structure, dynamics, and stability of lipid bilayers are controlled by thermodynamic forces, leading to overall tensionless membranes with a distinct lateral organization and a conspicuous lateral pressure profile. Bilayers are also subject to built-in curvature-stress instabilities that may be released locally or globally in terms of morphological changes leading to the formation of non-lamellar and curved structures. A key controller of the bilayer’s propensity to form curved structures is the average molecular shape of the different lipid molecules. Via the curvature stress, molecular shape mediates a coupling to membrane-protein function and provides a set of physical mechanisms for formation of lipid domains and laterally differentiated regions in the plane of the membrane. Unfortunately, these relevant physical features of membranes are often ignored in the most popular models for biological membranes. Results from a number of experimental and theoretical studies emphasize the significance of these fundamental physical properties and call for a refinement of the fluid mosaic model (and the accompanying raft hypothesis.

  9. Genistein, a general kinase inhibitor, as a potential antiviral for arenaviral hemorrhagic fever as described in the Pirital virus-Syrian golden hamster model.

    Science.gov (United States)

    Vela, Eric M; Knostman, Katherine A; Mott, Jason M; Warren, Richard L; Garver, Jennifer N; Vela, Lela Johnson; Stammen, Rachelle L

    2010-09-01

    Arenaviruses are rodent-borne negative strand RNA viruses and infection of these viruses in humans may result in disease and hemorrhagic fever. To date, supportive care, ribavirin, and in some cases immune plasma remain the foremost treatment options for arenaviral hemorrhagic fever. Research with the hemorrhagic fever causing-arenaviruses usually requires a Biosafety level (BSL)-4 environment; however, surrogate animal model systems have been developed to preliminarily study and screen various vaccines and antivirals. The Syrian golden hamster-Pirital virus (PIRV) surrogate model of hemorrhagic fever provides an opportunity to test new antivirals in an ABSL-3 setting. Thus, we challenged hamsters, implanted with telemetry, with PIRV and observed viremia and tissue viral titers, and changes in core body temperature, hematology, clinical chemistry, and coagulation parameters. Physical signs of disease of the PIRV-infected hamsters included weight loss, lethargy, petechial rashes, epistaxis, ocular orbital and rectal hemorrhage, and visible signs of neurologic disorders. However, treating animals with genistein, a plant derived isoflavone and general kinase inhibitor, resulted in increased survival rates and led to an improved clinical profile. In all, the results from this study demonstrate the potential of a general kinase inhibitor genistein as an antiviral against arenaviral hemorrhagic fever. 2010 Elsevier B.V. All rights reserved.

  10. Critical success factors model developing for sustainable Kaizen implementation in manufactur-ing industry in Ethiopia

    OpenAIRE

    Haftu Hailu; Abdelkadir Kedir; Getachew Bassa; Kassu Jilcha

    2017-01-01

    The purpose of the research is to identify critical success factors and model developing for sustaining kaizen implementation. Peacock shoe is one of the manufacturing industries in Ethiopia facing challenges on sustaining. The methodology followed is factor analysis and empirically testing hypothesis. A database was designed using SPSS version 20. The survey was validated using statistical validation using the Cronbach alpha index; the result is 0.908. The KMO index value was obtained for th...

  11. Social Dancing for Successful Ageing: Models for Health, Happiness and Social Inclusion amongst Senior Citizens

    Directory of Open Access Journals (Sweden)

    Jonathan Skinner

    2013-03-01

    Full Text Available Abstract: This article presents findings from a qualitative study of social dancing for successful ageing amongst senior citizens in three locales: in Blackpool (GB, around Belfast (NI, and in Sacramento (US. Findings also attest to the social, psychological and health benefits of social dancing amongst senior citizens. They also articulate three different social dancing models: social dance as tea dance (Sacramento, social dance as practice dance (Blackpool, social dance as motility (Belfast and environs.

  12. Comprehensive model of annual plankton succession based on the whole-plankton time series approach.

    Directory of Open Access Journals (Sweden)

    Jean-Baptiste Romagnan

    Full Text Available Ecological succession provides a widely accepted description of seasonal changes in phytoplankton and mesozooplankton assemblages in the natural environment, but concurrent changes in smaller (i.e. microbes and larger (i.e. macroplankton organisms are not included in the model because plankton ranging from bacteria to jellies are seldom sampled and analyzed simultaneously. Here we studied, for the first time in the aquatic literature, the succession of marine plankton in the whole-plankton assemblage that spanned 5 orders of magnitude in size from microbes to macroplankton predators (not including fish or fish larvae, for which no consistent data were available. Samples were collected in the northwestern Mediterranean Sea (Bay of Villefranche weekly during 10 months. Simultaneously collected samples were analyzed by flow cytometry, inverse microscopy, FlowCam, and ZooScan. The whole-plankton assemblage underwent sharp reorganizations that corresponded to bottom-up events of vertical mixing in the water-column, and its development was top-down controlled by large gelatinous filter feeders and predators. Based on the results provided by our novel whole-plankton assemblage approach, we propose a new comprehensive conceptual model of the annual plankton succession (i.e. whole plankton model characterized by both stepwise stacking of four broad trophic communities from early spring through summer, which is a new concept, and progressive replacement of ecological plankton categories within the different trophic communities, as recognised traditionally.

  13. Modelling metal-humic substances-surface systems: reasons for success, failure and possible routes for peace of mind

    International Nuclear Information System (INIS)

    Reiller, P.E.

    2012-01-01

    Iron oxides and oxy-hydroxides are commonly of considerable importance in the sorption of ions onto rocks, soils and sediments. They can be the controlling sorptive phases even if they are present in relatively small quantities. In common with other oxides and clay minerals, the sorption pH-edge of metals is directly linked to their hydrolysis: the higher the residual charge on the metal ion, the lower the pH-edge. Modelling of this process has been successfully carried out using different microscopic or macroscopic definitions of the interface (e.g. surface complexation or ion exchange models that may or may not include mineralogical descriptions). The influence of organic material on the sorption of many metals is of significant. This organic material includes simple organic molecules and more complex exo-polymeric substances (e.g. humic substances) produced by the decay of natural organic matter. Sorption of this organic material to mineral surfaces has been the subject of a large body of work. The various types of organic substances do not share the same affinities for mineral surfaces in general, and for iron oxides and oxy-hydroxides in particular. In those cases in which successful models of the component binary systems (i.e. metal-surface, metal-organic, organic-surface) have been developed, the formation of mixed surface complexes, the evolution of the surface itself, the addition order in laboratory systems, and the evolution of natural organic matter fractions during sorption, have often precluded a satisfactory description of metal-surface-organic ternary systems over a sufficiently wide range of parameter values (i.e. pH, ionic strength, concentration of humic substances). This manuscript describes the reasons for some successes and failures in the modelling of the ternary systems. Promising recent advances and possible methods of providing more complete descriptions of these intricate systems are also discussed. (author)

  14. Study of dynamical properties in a bi-dimensional model describing the prey–predator dynamics with strong Allee effect in prey.

    Directory of Open Access Journals (Sweden)

    Partha Mandal

    2017-12-01

    Full Text Available In this work, we analyze a bi-dimensional differential equation system obtained by considering Holling type II functional response in prey–predator model with strong Allee effect in prey. One of the important consequence of this modification is the existence of separatrix curve which divides the behaviour of the trajectories in the phase plane. The results show that the origin is an attractor for any set of parameter values. Axial equilibrium points are stable or unstable according to the different parametric restrictions. The unique positive equilibrium point, if it exists, can be either an attractor or a repeller surrounded by a limit cycle, whose stability and uniqueness are also established. Therefore long-term coexistence of both populations is possible or they can go to extinction. Conditions on the parameter values are derived to show that the positive equilibrium point can be emerged or annihilated through transcritical bifurcation at axial equilibrium points. The existence of two heteroclinic curves is also established. It is also demonstrated that the origin is a global attractor in the phase plane for some parameter values, which implies that there are satisfying conditions where both populations can go to extinction. Ecological interpretations of all analytical results are provided thoroughly.

  15. Spatial patterns of breeding success of grizzly bears derived from hierarchical multistate models.

    Science.gov (United States)

    Fisher, Jason T; Wheatley, Matthew; Mackenzie, Darryl

    2014-10-01

    Conservation programs often manage populations indirectly through the landscapes in which they live. Empirically, linking reproductive success with landscape structure and anthropogenic change is a first step in understanding and managing the spatial mechanisms that affect reproduction, but this link is not sufficiently informed by data. Hierarchical multistate occupancy models can forge these links by estimating spatial patterns of reproductive success across landscapes. To illustrate, we surveyed the occurrence of grizzly bears (Ursus arctos) in the Canadian Rocky Mountains Alberta, Canada. We deployed camera traps for 6 weeks at 54 surveys sites in different types of land cover. We used hierarchical multistate occupancy models to estimate probability of detection, grizzly bear occupancy, and probability of reproductive success at each site. Grizzly bear occupancy varied among cover types and was greater in herbaceous alpine ecotones than in low-elevation wetlands or mid-elevation conifer forests. The conditional probability of reproductive success given grizzly bear occupancy was 30% (SE = 0.14). Grizzly bears with cubs had a higher probability of detection than grizzly bears without cubs, but sites were correctly classified as being occupied by breeding females 49% of the time based on raw data and thus would have been underestimated by half. Repeated surveys and multistate modeling reduced the probability of misclassifying sites occupied by breeders as unoccupied to <2%. The probability of breeding grizzly bear occupancy varied across the landscape. Those patches with highest probabilities of breeding occupancy-herbaceous alpine ecotones-were small and highly dispersed and are projected to shrink as treelines advance due to climate warming. Understanding spatial correlates in breeding distribution is a key requirement for species conservation in the face of climate change and can help identify priorities for landscape management and protection. © 2014 Society

  16. Chaotic-dynamical conceptual model to describe fluid flow and contaminant transport in a fractured vadose zone. 1998 annual progress report

    International Nuclear Information System (INIS)

    Doughty, C.; Dragila, M.I.; Faybishenko, B.; Podgorney, R.K.; Stoops, T.M.; Wheatcraft, S.W.; Wood, T.R.

    1998-01-01

    'DOE faces the remediation of numerous contaminated sites, such as those at Hanford, INEEL, LLNL, and LBNL, where organic and/or radioactive wastes were intentionally or accidentally released to the vadose zone from surface spills, underground tanks, cribs, shallow ponds, and deep wells. Migration of these contaminants through the vadose zone has lead to the contamination of or threatens to contaminate underlying groundwater. A key issue in choosing a corrective action plan to clean up contaminated sites is to determine the location, total mass, mobility and travel time to receptors for contaminants moving in the vadose zone. These problems are difficult to solve in a technically defensible and accurate manner because contaminants travel downward intermittently through narrow pathways driven by variations in environmental conditions. These preferential pathways can be difficult to find and predict. The primary objective of this project is to determine if and when dynamical chaos theory can be used to investigate infiltration of fluid and contaminant transport in heterogeneous soils and fractured rocks. The objective of this project is being achieved through the following Activities (1) Evaluation of chaotic behavior of flow in laboratory and field experiments using methods from non-linear dynamics; (2) Evaluation of the impact these dynamics may have on contaminant transport through heterogeneous fractured rocks and soils, and how it can be used to guide remediation efforts; (3) Development of a conceptual model and mathematical and numerical algorithms for flow and transport, which incorporate both: (a) the spatial variability of heterogeneous porous and fractured media, and (b) the description of the temporal dynamics of flow and transport, which may be chaotic; and (4) Development of appropriate experimental field and laboratory techniques needed to detect diagnostic parameters for chaotic behavior of flow. This approach is based on the assumption that spatial

  17. Pathways to Life Success: A Conceptual Model of Financial Well-Being for Young Adults

    Science.gov (United States)

    Shim, Soyeon; Xiao, Jing J.; Barber, Bonnie L.; Lyons, Angela C.

    2009-01-01

    The purpose of this study is to describe and test a conceptual model of the potential antecedents and consequences of financial well-being in young adulthood. Data (N = 781) were collected via an online survey conducted at a large state university in the southwestern United States. Our results suggest that self-actualizing personal values,…

  18. Modelling vital success factors in adopting personalized medicine system in healthcare technology and management

    Directory of Open Access Journals (Sweden)

    Subhas C. Misra

    2018-06-01

    Full Text Available Biomedical engineering has grown as a vast field of research that includes many areas of engineering and technology also. Personalized Medicine is an emerging approach in today’s medicare system. It bears a very strong potential to consolidate modern e-health systems fundamentally. Scientists have already discovered some of the personalized drugs that can shift the whole medicare system into a new dimension. However, bringing the change in the whole medicare system is not an easy task. There are several factors that can affect the successful adoption of Personalized Medicine systems in the healthcare management sector. This paper aims at identifying the critical factors with the help of an empirical study. A questionnaire was distributed amongst some clinicians, clinical researchers, practitioners in pharmaceutical industries, regulatory board members, and a larger section of patients. The response data collected thereby were analyzed by using appropriate statistical methods. Based on the statistical analysis, an attempt is made to prepare a list of critical success factors in the adoption of personalized medicine in healthcare management. The study indicates that eight of the thirteen hypothesized factors have statistical relationship with “Success”. The important success factors detected are: data management, team work and composition, privacy and confidentiality, mind-set, return on investment, sufficient time, R&D and alignment. To the best of our knowledge, this is the first academic paper in which an attempt has been made to model the vital critical factors for the successful implementation of Personalized Medicine in healthcare management. The study bears the promise of important applications in healthcare engineering and technology. Keywords: Healthcare management, Personalized medicine, E-health, Success factors, Medicare systems, Regression analysis

  19. Application of two forest succession models at sites in Northeast Germany

    International Nuclear Information System (INIS)

    Lasch, P.; Lindner, M.

    1995-06-01

    In order to simulate potential impacts of climate change on forests, two succession models were applied to sites in the Northeast German lowlands. The models, which had been developed for Alpine (FORECE) and Boreal (FORSKA) forests differ from each other in the way they represent tree growth processes and the impact of environmental factors on establishment and growth. Both models were adjusted and compared with each other at sites that are situated along an ecological gradient from maritime to subcontinental climate. These sites are extending the former environmental space of model application towards water limited conditions, which under a predicted climatic change may have increasing importance for European forests. First results showed that FORECE was unrealistically sensitive to changes in soil moisture. On the other hand, FORSKA generally simulated very low biomasses. Since the structure of FORSKA seemed to be better suited for the simulation of changing environmental conditions, this model was chosen for further model development, applications and sensitivity analyses. Among other changes, establishment rates were increased and some environmental response factors were analysed. The function of account for resource depletion was modified. After the modifications for Central European conditions were made, there was a decrease in performance for the Boreal site. Both simulated total biomasses and species composition had changed. We conclude, that with currently available models, realistic forest dynamics within different climatic zones of Europe cannot be simulated without more substantial model modifications. (orig.)

  20. Successful N2 leptogenesis with flavour coupling effects in realistic unified models

    International Nuclear Information System (INIS)

    Bari, Pasquale Di; King, Stephen F.

    2015-01-01

    In realistic unified models involving so-called SO(10)-inspired patterns of Dirac and heavy right-handed (RH) neutrino masses, the lightest right-handed neutrino N 1 is too light to yield successful thermal leptogenesis, barring highly fine tuned solutions, while the second heaviest right-handed neutrino N 2 is typically in the correct mass range. We show that flavour coupling effects in the Boltzmann equations may be crucial to the success of such N 2 dominated leptogenesis, by helping to ensure that the flavour asymmetries produced at the N 2 scale survive N 1 washout. To illustrate these effects we focus on N 2 dominated leptogenesis in an existing model, the A to Z of flavour with Pati-Salam, where the neutrino Dirac mass matrix may be equal to an up-type quark mass matrix and has a particular constrained structure. The numerical results, supported by analytical insight, show that in order to achieve successful N 2 leptogenesis, consistent with neutrino phenomenology, requires a ''flavour swap scenario'' together with a less hierarchical pattern of RH neutrino masses than naively expected, at the expense of some mild fine-tuning. In the considered A to Z model neutrino masses are predicted to be normal ordered, with an atmospheric neutrino mixing angle well into the second octant and the Dirac phase δ≅ 20 o , a set of predictions that will be tested in the next years in neutrino oscillation experiments. Flavour coupling effects may be relevant for other SO(10)-inspired unified models where N 2 leptogenesis is necessary

  1. Relating Successful Business Models to Intellectual Capital and Knowledge Management Practices

    DEFF Research Database (Denmark)

    Nielsen, Christian

    2018-01-01

    management, mediated by intellectual capital, and draws up a schema by which the relationships can be described and discussed. It concludes by synthesizing a future research agenda to further address these relationships and to strengthen our understanding of how they improve the value creation......There are a number of natural links between the fields of business models and knowledge management. The contemporary understanding of business models is that they are concerned with describing and analyzing the methods of value creation and the alternative ways of delivering use value to customers...... that are applied by organizations. Similarly, knowledge management also has intricate connections with mechanisms of value creation, through the structuring and improvement of knowledge processes in a given organization. Ensuring that the right knowledge is present is an important part of any business model...

  2. Modelling the interactions among factors that influence successful computerisation of small business

    Directory of Open Access Journals (Sweden)

    Gerard Fogarty

    2008-05-01

    Full Text Available Small businesses face many problems if they are to survive the first five years of operation. The increasing complexity of information needed to run a business in the 21st Century has added another obstacle to what is already a tough course. Sooner or later, survivors are faced with the prospect of investing in computer based information systems (CBIS. Properly handled, the investment will improve the competitiveness of the company. Badly handled, the investment will handicap the company and perhaps even lead to its closure. Using survey methodology, the present study collected information from 171 small businesses that had purchased computer systems with a view to finding out what factors contribute to successful implementation of CBIS. The variables studied included background characteristics of the organization, background characteristics of the Chief Executive Officer, decision making processes, and a range of variables relating to the performance of the system itself. The outcome variable was user satisfaction. We developed and tested a CBIS implementation success model based on these variables. Results showed that although the performance of the system was the immediate determinant of satisfaction, the background variables had both direct and indirect (mediated effects on satisfaction. These findings emphasise the importance of going beyond the immediate surrounds of a computing environment if one wishes to explain the factors that influence CBIS success in small businesses.

  3. Performance evaluation of public hospital information systems by the information system success model.

    Science.gov (United States)

    Cho, Kyoung Won; Bae, Sung-Kwon; Ryu, Ji-Hye; Kim, Kyeong Na; An, Chang-Ho; Chae, Young Moon

    2015-01-01

    This study was to evaluate the performance of the newly developed information system (IS) implemented on July 1, 2014 at three public hospitals in Korea. User satisfaction scores of twelve key performance indicators of six IS success factors based on the DeLone and McLean IS Success Model were utilized to evaluate IS performance before and after the newly developed system was introduced. All scores increased after system introduction except for the completeness of medical records and impact on the clinical environment. The relationships among six IS factors were also analyzed to identify the important factors influencing three IS success factors (Intention to Use, User Satisfaction, and Net Benefits). All relationships were significant except for the relationships among Service Quality, Intention to Use, and Net Benefits. The results suggest that hospitals should not only focus on systems and information quality; rather, they should also continuously improve service quality to improve user satisfaction and eventually reach full the potential of IS performance.

  4. A domestic model for successful implementation of enterprise resource planning (ERP systems in Iranian manufacturing enterprises

    Directory of Open Access Journals (Sweden)

    Mohammad Rahmani

    2012-01-01

    Full Text Available This research investigates the human-behavioral dimension of technology acceptance in enterprises. It is evident that accepting a technology depends on the underlying circumstances of the environment. We have approached this issue from two different angles of social and technological architecture. The research tries to explore proper enterprise architecture for ERP system acceptance. Social Architecture (SA is defined as the set of circumstances that makes people behave in a particular way. So behavior of persons (employees of an enterprise can be a function of SA. Hence acceptance of a system can be dictated by SA and manipulating SA can result in desirable success for a technology system. We have achieved various variables of social architecture and have examined their relevance to system acceptance and success in related enterprises (research domain beside technological architecture variables. The results have indicated that a special form of social and technological architecture can lead to success for ERP system in the enterprises of the research domain. This gave us a model of architecture.

  5. Collaborative Testing as a Model for Addressing Equity in Student Success in STEM Classes

    Science.gov (United States)

    Dileonardo, C.; James, B. R.

    2016-12-01

    Introductory Earth science classes at two-year colleges play a critical role as "gateway courses" for underrepresented student populations into undergraduate STEM programs. Students entering college underprepared in math and science typically receive their only exposure to science at the undergraduate level in introductory courses in the Earth and space sciences. In many colleges a huge disparity exists in these classes between success rates amongst students from groups traditionally represented in the STEM fields and those from underrepresented populations. Closing the equity gap in success in these courses is a major focus of many pilot projects nationally. This concern has also led to the adoption of new teaching and learning practices, based on research in learning, in introductory Earth science pedagogy. Models of teaching practices including greater engagement, active learning approaches, and collaborative learning structures seem to help with student achievement in introductory courses. But, whereas these practices might increase overall student success they have not proven to close the equity gap in achievement. De Anza a two-year college in the San Francisco bay area has a long history in the geology department of incorporating and testing teaching practices developed out of research in learning. Collaborative learning has infused every aspect of our learning approaches in the Earth sciences, including laboratory, fieldwork, and test preparation. Though these approaches seemed to have educational benefit the huge equity gap department-wide persisted between targeted and non-targeted populations. Three years ago collaborative testing models were introduced into our geology and meteorology classes. The mechanism included methods for directly comparing collaborative to individual testing. The net result was that targeted populations including African Americans, Latinos, and Filipinos increased steadily at around 3.5% per year from 66% to 73%. The overall

  6. Empirical Succession Mapping and Data Assimilation to Constrain Demographic Processes in an Ecosystem Model

    Science.gov (United States)

    Kelly, R.; Andrews, T.; Dietze, M.

    2015-12-01

    Shifts in ecological communities in response to environmental change have implications for biodiversity, ecosystem function, and feedbacks to global climate change. Community composition is fundamentally the product of demography, but demographic processes are simplified or missing altogether in many ecosystem, Earth system, and species distribution models. This limitation arises in part because demographic data are noisy and difficult to synthesize. As a consequence, demographic processes are challenging to formulate in models in the first place, and to verify and constrain with data thereafter. Here, we used a novel analysis of the USFS Forest Inventory Analysis to improve the representation of demography in an ecosystem model. First, we created an Empirical Succession Mapping (ESM) based on ~1 million individual tree observations from the eastern U.S. to identify broad demographic patterns related to forest succession and disturbance. We used results from this analysis to guide reformulation of the Ecosystem Demography model (ED), an existing forest simulator with explicit tree demography. Results from the ESM reveal a coherent, cyclic pattern of change in temperate forest tree size and density over the eastern U.S. The ESM captures key ecological processes including succession, self-thinning, and gap-filling, and quantifies the typical trajectory of these processes as a function of tree size and stand density. Recruitment is most rapid in early-successional stands with low density and mean diameter, but slows as stand density increases; mean diameter increases until thinning promotes recruitment of small-diameter trees. Strikingly, the upper bound of size-density space that emerges in the ESM conforms closely to the self-thinning power law often observed in ecology. The ED model obeys this same overall size-density boundary, but overestimates plot-level growth, mortality, and fecundity rates, leading to unrealistic emergent demographic patterns. In particular

  7. Self-management model in the scheduling of successive appointments in rheumatology.

    Science.gov (United States)

    Castro Corredor, David; Cuadra Díaz, José Luis; Mateos Rodríguez, Javier José; Anino Fernández, Joaquín; Mínguez Sánchez, María Dolores; de Lara Simón, Isabel María; Tébar, María Ángeles; Añó, Encarnación; Sanz, María Dolores; Ballester, María Nieves

    2018-01-08

    The rheumatology service of Ciudad Real Hospital, located in an autonomous community of that same name that is nearly in the center of Spain, implemented a self-management model of successive appointments more than 10 years ago. Since then, the physicians of the department schedule follow-up visits for their patients depending on the disease, its course and ancillary tests. The purpose of this study is to evaluate and compare the self-management model for successive appointments in the rheumatology service of Ciudad Real Hospital versus the model of external appointment management implemented in 8 of the hospital's 15 medical services. A comparative and multivariate analysis was performed to identify variables with statistically significant differences, in terms of activity and/or performance indicators and quality perceived by users. The comparison involved the self-management model for successive appointments employed in the rheumatology service of Ciudad Real Hospital and the model for external appointment management used in 8 hospital medical services between January 1 and May 31, 2016. In a database with more than 100,000 records of appointments involving the set of services included in the study, the mean waiting time and the numbers of non-appearances and rescheduling of follow-up visits in the rheumatology department were significantly lower than in the other services. The number of individuals treated in outpatient rheumatology services was 7,768, and a total of 280 patients were surveyed (response rate 63.21%). They showed great overall satisfaction, and the incidence rate of claims was low. Our results show that the self-management model of scheduling appointments has better results in terms of activity indicators and in quality perceived by users, despite the intense activity. Thus, this study could be fundamental for decision making in the management of health care organizations. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de

  8. Modeling N Cycling during Succession after Forest Disturbance: an Analysis of N Mining and Retention Hypothesis

    Science.gov (United States)

    Zhou, Z.; Ollinger, S. V.; Ouimette, A.; Lovett, G. M.; Fuss, C. B.; Goodale, C. L.

    2017-12-01

    Dissolved inorganic nitrogen losses at the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA, have declined in recent decades, a pattern that counters expectations based on prevailing theory. An unbalanced ecosystem nitrogen (N) budget implies there is a missing component for N sink. Hypotheses to explain this discrepancy include increasing rates of denitrification and accumulation of N in mineral soil pools following N mining by plants. Here, we conducted a modeling analysis fused with field measurements of N cycling, specifically examining the hypothesis relevant to N mining and retention in mineral soils. We included simplified representations of both mechanisms, N mining and retention, in a revised ecosystem process model, PnET-SOM, to evaluate the dynamics of N cycling during succession after forest disturbance at the HBEF. The predicted N mining during the early succession was regulated by a metric representing a potential demand of extra soil N for large wood growth. The accumulation of nitrate in mineral soil pools was a function of the net aboveground biomass accumulation and soil N availability and parameterized based on field 15N tracer incubation data. The predicted patterns of forest N dynamics were consistent with observations. The addition of the new algorithms also improved the predicted DIN export in stream water with an R squared of 0.35 (Ppay back the mined N in mineral soils. Predicted ecosystem N balance showed that N gas loss could account for 14-46% of the total N deposition, the soil mining about 103% during the early succession, and soil retention about 35% at the current forest stage at the HBEF.

  9. A successive order of scattering model for solving vector radiative transfer in the atmosphere

    International Nuclear Information System (INIS)

    Min Qilong; Duan Minzheng

    2004-01-01

    A full vector radiative transfer model for vertically inhomogeneous plane-parallel media has been developed by using the successive order of scattering approach. In this model, a fast analytical expansion of Fourier decomposition is implemented and an exponent-linear assumption is used for vertical integration. An analytic angular interpolation method of post-processing source function is also implemented to accurately interpolate the Stokes vector at arbitrary angles for a given solution. It has been tested against the benchmarks for the case of randomly orientated oblate spheroids, illustrating a good agreement for each stokes vector (within 0.01%). Sensitivity tests have been conducted to illustrate the accuracy of vertical integration and angle interpolation approaches. The contribution of each scattering order for different optical depths and single scattering albedos are also analyzed

  10. An Institutional Model for Improving Student Retention and Success at the University of Pretoria

    Directory of Open Access Journals (Sweden)

    Nthabiseng Audrey Ogude

    2012-03-01

    Full Text Available A concerted institutional approach to improving student outcomes resulted in a faculty-based, student-focussed model for student success at the University of Pretoria (UP. The student academic development and excellence model (SADEM, developed by a Steering Committee for student success, employs developmental research and systems theory and targets all years of undergraduate study while prioritising the first year. Underpinned by a systemic metric framework and continuous improvement, interventions comprise institutional and faculty-based projects that target high impact modules and diverse students to improve retention, pass, and throughput rates. Though context specific, it offers solutions to international concerns - lack of a systemic approach; initiatives located in  peripheral units; initiatives located outside academic disciplines and lack of participation by academic staff and a focus on retention of limited student subgroups instead of retention, pass, graduation and throughput rates of all students. The circumstances that led to its development, its key features and application at the UP, ways it can be adapted to other contexts, as well as its limitations and possible future directions are presented.

  11. Five Describing Factors of Dyslexia

    Science.gov (United States)

    Tamboer, Peter; Vorst, Harrie C. M.; Oort, Frans J.

    2016-01-01

    Two subtypes of dyslexia (phonological, visual) have been under debate in various studies. However, the number of symptoms of dyslexia described in the literature exceeds the number of subtypes, and underlying relations remain unclear. We investigated underlying cognitive features of dyslexia with exploratory and confirmatory factor analyses. A…

  12. Evaluation of a comprehensive EHR based on the DeLone and McLean model for IS success: approach, results, and success factors.

    Science.gov (United States)

    Bossen, Claus; Jensen, Lotte Groth; Udsen, Flemming Witt

    2013-10-01

    The article describes the methodological approach to, and results of an evaluation of a comprehensive electronic health record (EHR) in the shake down phase, shortly after its implementation at a regional hospital in Denmark. A formative evaluation based on a mixed-methods case study, designed to be interactive and concurrent was conducted at two hospital departments based on the updated DeLone and McLean framework for evaluating information systems success. To ascertain user assessments of the EHR, we distributed a questionnaire two months after implementation to four groups of staff (physicians, nurses, medical secretaries, and physiotherapists; n=244), and at the same time we conducted thirteen individual, semi-structured interviews with representatives from these four groups. Subsequently, seven follow-up focus group interviews were conducted with the four above-mentioned groups, in order to go deeper into specific user assessments. Simultaneously, focus group interviews with two IT departments and the implementation team were conducted, to gain insight into system provider assessments of the implementation process and the EHR. Before, during, and after implementation, 88 h of ethnographic observation were carried out, to give the researchers an understanding of the daily routine of staff, and their use of health records. Finally, daily system performance data were obtained, to gather factual information on system response and downtime. Overall, staff had positive experiences with the EHR and its operational reliability, response time, login and support. Performance was acceptable. Medical secretaries found the use of the patient administration module cumbersome, and physicians found the establishment of the overview of professionally relevant data challenging. There were demands for improvements to these and other functionalities, and for the EHR to be integrated with other systems and databases. Evaluations immediately following implementation are inherently

  13. Hierarchical Bayesian Markov switching models with application to predicting spawning success of shovelnose sturgeon

    Science.gov (United States)

    Holan, S.H.; Davis, G.M.; Wildhaber, M.L.; DeLonay, A.J.; Papoulias, D.M.

    2009-01-01

    The timing of spawning in fish is tightly linked to environmental factors; however, these factors are not very well understood for many species. Specifically, little information is available to guide recruitment efforts for endangered species such as the sturgeon. Therefore, we propose a Bayesian hierarchical model for predicting the success of spawning of the shovelnose sturgeon which uses both biological and behavioural (longitudinal) data. In particular, we use data that were produced from a tracking study that was conducted in the Lower Missouri River. The data that were produced from this study consist of biological variables associated with readiness to spawn along with longitudinal behavioural data collected by using telemetry and archival data storage tags. These high frequency data are complex both biologically and in the underlying behavioural process. To accommodate such complexity we developed a hierarchical linear regression model that uses an eigenvalue predictor, derived from the transition probability matrix of a two-state Markov switching model with generalized auto-regressive conditional heteroscedastic dynamics. Finally, to minimize the computational burden that is associated with estimation of this model, a parallel computing approach is proposed. ?? Journal compilation 2009 Royal Statistical Society.

  14. Triple Diagonal modeling: A mechanism to focus productivity improvement for business success

    Energy Technology Data Exchange (ETDEWEB)

    Levine, L.O. [Pacific Northwest Lab., Richland, WA (United States); Villareal, L.D. [Army Depot, Corpus Christi, TX (United States)

    1993-09-01

    Triple Diagonal (M) modeling is a technique to help quickly diagnose an organization`s existing production system and to identify significant improvement opportunities in executing, controlling, and planning operations. TD modeling is derived from ICAM Definition Language (IDEF 0)-also known as Structured Analysis and Design Technique. It has been used successfully at several Department of Defense remanufacturing facilities trying to accomplish significant production system modernization. TD has several advantages over other modeling techniques. First, it quickly does ``As-ls`` analysis and then moves on to identify improvements. Second, creating one large diagram makes it easier to share the TD model throughout an organization, rather than the many linked 8 1/2 {times} 11`` drawings used in traditional decomposition approaches. Third, it acts as a communication mechanism to share understanding about improvement opportunities that may cross existing functional/organizational boundaries. Finally, TD acts as a vehicle to build a consensus on a prioritized list of improvement efforts that ``hangs togethers as an agenda for systemic changes in the production system and the improved integration of support functions.

  15. Cellular aging (the Hayflick limit) and species longevity: a unification model based on clonal succession.

    Science.gov (United States)

    Juckett, D A

    1987-03-01

    A model is presented which proposes a specific cause-and-effect relationship between a limited cell division potential and the maximum lifespan of humans and other mammals. It is based on the clonal succession hypothesis of Kay which states that continually replicating cell beds (e.g. bone marrow, intestinal crypts, epidermis) could be composed of cells with short, well-defined division potentials. In this model, the cells of these beds are proposed to exist in an ordered hierarchy which establishes a specific sequence for cell divisions throughout the organism's lifespan. The depletion of division potential at all hierarchical levels leads to a loss of bed function and sets an intrinsic limit to species longevity. A specific hierarchy for cell proliferation is defined which allows the calculation of time to bed depletion and, ultimately, to organism mortality. The model allows the existence of a small number (n) of critical cell beds within the organism and defines organism death as the inability of any one of these beds to produce cells. The model is consistent with all major observations related to cellular and organismic aging. In particular, it links the PDLs (population doubling limit) observed for various species to their mean lifespan; it explains the slow decline in PDL as a function of age of the donor; it establishes a thermodynamically stable maximum lifespan for a disease-free population; and it can explain why tissue transplants outlive donors or hosts.

  16. Chronic care model for the management of depression: synthesis of barriers to, and facilitators of, success.

    Science.gov (United States)

    Holm, Anne Lise; Severinsson, Elisabeth

    2012-12-01

    Depression is a socially- and physically-disabling condition. The Chronic Care Model (CCM) was developed to promote better management of long-term conditions, such as depression, in primary care settings. The aim of the study was to identify barriers to, and facilitators of, success when implementing the CCM for the management of depression in primary care. A systematic search was conducted in electronic databases from January 2005 to December 2011. Thirteen articles met the inclusion criteria and were reviewed by means of a thematic analysis. The barriers were categorized under two themes: lack of organizational, administrative, and professional ability to change and implement the components of the CCM; and lack of clarity pertaining to the responsibility inherent in the role of care manager (often a nurse) when it comes to promoting the patient's self-management ability. In terms of the facilitators of success, two themes emerged: leadership support and vision, and redesigning the delivery system. When shaping an environment for organizational change, leadership and professionals must work towards a common goal and vision. Such processes require a care manager with a clear role and responsibilities in order for the health-care system to meet the needs of the person with depression. © 2012 The Authors. International Journal of Mental Health Nursing © 2012 Australian College of Mental Health Nurses Inc.

  17. Leadership models and behaviors for sales executives. What drives success and the best results?

    Directory of Open Access Journals (Sweden)

    Dünnweber Matthias

    2017-07-01

    Full Text Available The paper analyses the effectiveness of the best leadership models and behaviours that are used by sales executives. Although, the impact of the most common characteristics and behaviours used in sales have been researched very well, recent research has only very limited results on a comparison of the most successful leadership personality traits and behaviours depending on companies’ situation and the context. In this paper we analyse two different situations: dynamic environment and stable environment. The context in this paper refers to the area sales. The paper will provide an explanation of the most successful leadership style used in sales and the characteristics of it and why they are also very useful in a sales process. Additionally, we will analyse the effectiveness of these characteristics in the two different situations of a company and exclusively in the sales context. We argue that the characteristics can be defined as the most effective one in every situation and context. We will develop a theoretical overview that shows clearly the best leadership traits and behaviours for each of the two situations in sales that is based on a literature research. The theoretical frameworks will be adjusted and confirmed with three senior sales executives from three different industries. The results of this paper will provide sales executives useful and easy to understand information about the advantages and disadvantages of the different leadership traits and behaviours depending on the context in and situation.

  18. Predicting the success of IVF: external validation of the van Loendersloot's model.

    Science.gov (United States)

    Sarais, Veronica; Reschini, Marco; Busnelli, Andrea; Biancardi, Rossella; Paffoni, Alessio; Somigliana, Edgardo

    2016-06-01

    Is the predictive model for IVF success proposed by van Loendersloot et al. valid in a different geographical and cultural context? The model discriminates well but was less accurate than in the original context where it was developed. Several independent groups have developed models that combine different variables with the aim of estimating the chance of pregnancy with IVF but only four of them have been externally validated. One of these four, the van Loendersloot's model, deserves particular attention and further investigation for at least three reasons; (i) the reported area under the receiver operating characteristics curve (c-statistics) in the temporal validation setting was the highest reported to date (0.68), (ii) the perspective of the model is clinically wise since it includes variables obtained from previous failed cycles, if any, so it can be applied to any women entering an IVF cycle, (iii) the model lacks external validation in a geographically different center. Retrospective cohort study of women undergoing oocyte retrieval for IVF between January 2013 and December 2013 at the infertility unit of the Fondazione Ca' Granda, Ospedale Maggiore Policlinico of Milan, Italy. Only the first oocyte retrieval cycle performed during the study period was included in the study. Women with previous IVF cycles were excluded if the last one before the study cycle was in another center. The main outcome was the cumulative live birth rate per oocytes retrieval. Seven hundred seventy-two women were selected. Variables included in the van Loendersloot's model and the relative weights (beta) were used. The variable resulting from this combination (Y) was transformed into a probability. The discriminatory capacity was assessed using the c-statistics. Calibration was made using a logistic regression that included Y as the unique variable and live birth as the outcome. Data are presented using both the original and the calibrated models. Performance was evaluated

  19. Putting patients first: a novel patient-centered model for medical enterprise success.

    Science.gov (United States)

    Dhawan, Naveen

    2014-01-01

    This article introduces a new way of viewing patient-customers. It encourages a greater emphasis on patients' needs and the importance of considering dimensions of the patient experience to better serve them. It also draws from examples in the general business world as they can be applied to medical enterprises. The author introduces a model that directs all business activities toward the end consumer with an underlying guidance by patient needs. A business is advised to understand its customer, design a patient-directed vision, and focus on creating a unique customer experience. The article delineates key action items for physicians and administrators that will allow them to better meet their patient-customers' needs and develop loyalty. By practicing a patient-centered approach and following these guidelines, one may ensure greater success of the medical enterprise.

  20. Modeling community succession and assembly: A novel method for network evolution

    Directory of Open Access Journals (Sweden)

    WenJun Zhang

    2012-06-01

    Full Text Available The process of modeling community succession and assembly is in some sense a method for network evolution, as done by Barabasi and Albert (1999. It is also one of the methods to create a sample networkfrom the statistic network I proposed earlier. I think that the mechanism of network evolution supposed by Barabasi and Albert is most likely applicable to the natural phenomena with emergency property. For natural phenomena without emergency property, the present study indicated that a scale-free network may be produced through a new mechanism, i.e., whether the connection of a taxon x occurs, dependent on the type and property of taxon y (in particular, the degree of its direct correlation with x to be connected but not necessarily the existing number of connections of taxon y, as proposed in present study.

  1. Using a micro-level model to generate a macro-level model of productive successful aging.

    Science.gov (United States)

    Johnson, Jessica K M; Sarkisian, Natalia; Williamson, John B

    2015-02-01

    Aging successfully entails good physical and cognitive health, as well as ongoing participation in social and productive activity. This study hones in on participation in productive activity, a factor that makes an important contribution to successful aging. One conceptual model of productive activity in later life specifies the antecedents and consequences of productivity. This study draws on that micro-level model to develop a corresponding macro-level model and assesses its utility for examining the predictors of and explaining the relationships between one form of productivity (labor force participation rates) and one aspect of well-being (average life expectancy) among males and females. Random effects regression models and path analysis were used to analyze cross-national longitudinal data for 24 high-income Organization for Economic Co-operation and Development (OECD) countries at seven time points (1980-2010; 168 observations total). OECD countries with higher labor force participation rates among older workers have higher life expectancies. Labor force participation mediates the effects of gross domestic product per capita on male and female life expectancy, and it mediates the effect of self-employment rate for men, but it acts as a suppressor with regard to the effect of public spending on male and female life expectancy. A well-known micro-level model of productive activity can be fruitfully adapted to account for macro-level cross-national variation in productivity and well-being. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Recent Successes of Wave/Turbulence Driven Models of Solar Wind Acceleration

    Science.gov (United States)

    Cranmer, S. R.; Hollweg, J. V.; Chandran, B. D.; van Ballegooijen, A. A.

    2010-12-01

    A key obstacle in the way of producing realistic simulations of the Sun-heliosphere system is the lack of a first-principles understanding of coronal heating. Also, it is still unknown whether the solar wind is "fed" through flux tubes that remain open (and are energized by footpoint-driven wavelike fluctuations) or if mass and energy are input intermittently from closed loops into the open-field regions. In this presentation, we discuss self-consistent models that assume the energy comes from solar Alfven waves that are partially reflected, and then dissipated, by magnetohydrodynamic turbulence. These models have been found to reproduce many of the observed features of the fast and slow solar wind without the need for artificial "coronal heating functions" used by earlier models. For example, the models predict a variation with wind speed in commonly measured ratios of charge states and elemental abundances that agrees with observed trends. This contradicts a commonly held assertion that these ratios can only be produced by the injection of plasma from closed-field regions on the Sun. This presentation also reviews two recent comparisons between the models and empirical measurements: (1) The models successfully predict the amplitude and radial dependence of Faraday rotation fluctuations (FRFs) measured by the Helios probes for heliocentric distances between 2 and 15 solar radii. The FRFs are a particularly sensitive test of turbulence models because they depend not only on the plasma density and Alfven wave amplitude in the corona, but also on the turbulent correlation length. (2) The models predict the correct sense and magnitude of changes seen in the polar high-speed solar wind by Ulysses from the previous solar minimum (1996-1997) to the more recent peculiar minimum (2008-2009). By changing only the magnetic field along the polar magnetic flux tube, consistent with solar and heliospheric observations at the two epochs, the model correctly predicts that the

  3. Italian industrial districts: A model of success or a weak productive system?

    Directory of Open Access Journals (Sweden)

    Daniele Schilirò

    2012-10-01

    Full Text Available The present contribution focuses on two issues. The first one concerns the characteristics of industrial districts and the increasing weight of these districts in the Italian system of production. The second issue is about the competitiveness of the Italian industrial districts, if they represent a model of success or rather a weak system of production. Thus, the transformation of the industrial districts is examined and the strengths and weaknesses are highlighted. One argument that comes out of this investigation is that industrial districts are strongly influenced by institutions, territory, and also by the social and cultural environment. The second argument regards the competitiveness of this Italian industrial development model, based on SMEs, which is founded on the specialization of productions, on innovation and internationalization. The paper argues that this model, which represents the ``Made in Italy'', is still a strong and dynamic system which has shown good performances and it represents a paradigm of lasting competitiveness, even if it is restrained by many external chronic constraints.

  4. Introduction of an Evaluation Tool to Predict the Probability of Success of Companies: The Innovativeness, Capabilities and Potential Model (ICP

    Directory of Open Access Journals (Sweden)

    Michael Lewrick

    2009-05-01

    Full Text Available Successful innovation requires management and in this paper a model to help manage the innovation process is presented. This model can be used to audit the management capability to innovate and to monitor how sales increase is related to innovativeness. The model was developed from a study of companies in the high technology cluster around Munich and validated using statistical procedures. The model was found to be effective at predicting the success or otherwise of the innovation strategy pursued by the company. The use of this model and how it can be used to identify areas for improvement are documented in this paper.

  5. Describing treatment effects to patients.

    Science.gov (United States)

    Moxey, Annette; O'Connell, Dianne; McGettigan, Patricia; Henry, David

    2003-11-01

    To examine the impact of different presentations of equivalent information (framing) on treatment decisions faced by patients. A systematic review of the published literature was conducted. English language publications allocating participants to different frames were retrieved using electronic and bibliographic searches. Two reviewers examined each article for inclusion, and assessed methodological quality. Study characteristics were tabulated and where possible, relative risks (RR; 95% confidence intervals) were calculated to estimate intervention effects. Thirty-seven articles, yielding 40 experimental studies, were included. Studies examined treatment (N = 24), immunization (N = 5), or health behavior scenarios (N = 11). Overall, active treatments were preferred when outcomes were described in terms of relative rather than absolute risk reductions or number needed to treat. Surgery was preferred to other treatments when treatment efficacy was presented in a positive frame (survival) rather than a negative frame (mortality) (relative risk [RR] = 1.51, 95% confidence interval [CI], 1.39 to 1.64). Framing effects were less obvious for immunization and health behavior scenarios. Those with little interest in the behavior at baseline were influenced by framing, particularly when information was presented as gains. In studies judged to be of good methodological quality and/or examining actual decisions, the framing effect, although still evident, was less convincing compared to the results of all included studies. Framing effects varied with the type of scenario, responder characteristics, scenario manipulations, and study quality. When describing treatment effects to patients, expressing the information in more than one way may present a balanced view to patients and enable them to make informed decisions.

  6. Incumbent Decisions about Succession Transitions in Family Firms: A Conceptual Model

    OpenAIRE

    Britta Boyd; Isabel C. Botero; Tomasz A. Fediuk

    2014-01-01

    In the family business literature, succession research has focused on the family member as they enter the leadership role or on the different issues that affect the succession process. Although researchers have acknowledged that succession in family businesses is “punctuated” by decision making events, less attention has been given to understanding how incumbents make decisions about ownership and management transitions. In an effort to continue to understand the succession process it is impo...

  7. A mathematical model for describing the retinal nerve fiber bundle trajectories in the human eye : Average course, variability, and influence of refraction, optic disc size and optic disc position

    NARCIS (Netherlands)

    Jansonius, Nomdo M.; Schiefer, Julia; Nevalainen, Jukka; Paetzold, Jens; Schiefer, Ulrich

    2012-01-01

    Previously we developed a mathematical model for describing the retinal nerve fiber bundle trajectories in the superior-temporal and inferior-temporal regions of the human retina, based on traced trajectories extracted from fundus photographs. Aims of the current study were to (i) validate the

  8. Fundamental Moral Attitudes to Animals and Their Role in Judgment: An Empirical Model to Describe Fundamental Moral Attitudes to Animals and Their Role in Judgment on the Culling of Healthy Animals During an Animal Disease Epidemic

    NARCIS (Netherlands)

    Cohen, N.E.; Brom, F.W.A.; Stassen, E.N.

    2009-01-01

    In this paper, we present and defend the theoretical framework of an empirical model to describe people’s fundamental moral attitudes (FMAs) to animals, the stratification of FMAs in society and the role of FMAs in judgment on the culling of healthy animals in an animal disease epidemic. We used

  9. PEMETAAN MODEL KERAWANAN LEPTOSPIROSIS BERDASARKAN FAKTOR RISIKO LINGKUNGAN DAN TRAP SUCCESS DI BANTUL, YOGYAKARTA

    Directory of Open Access Journals (Sweden)

    Sunaryo Sunaryo

    2016-09-01

    Full Text Available ABSTRACTLeptospirosis is zoonotic disease, which is caused by leptospira bacteria and transmitted to human bycontact with contaminated animal urine. Bantul District is endemic area of leptospirosis, case fatality rateas much 11% in 2010. The aim of this research was to study distribution of spatial epidemiologyleptospirosis, and mapping of vulnerable leptospirosis model by using Geographical Information Systembased on environmental risk factor and trap success in Bantul.This research done in March until November2011, and applied spatial analysis by using cross sectional design. Result of this research• showedleptospirosis cases in 2011 reaching 135 cases, and group of adult men was dominant, mostly as farmer andveteriner worker. There were three claster with average distance between cases: 0 km and furthermost 30km. Leptospirosis pattern increased in March and April when high rainfall. Medium rainfall spatial,lowland, vegetation index medium, alluvial type of soil, existence of rat and landuse of ricefield wereenvironmental variable influence leptospirosis cases. High vulnerable leptospirosis zone located in Centerand West Bantul.Keyword : Mapping, leptospirosis, vulnerable model. ABSTRAK Leptospirosis merupakan penyakit bersumber rodensia, disebabkan oleh bakteri leptospira, menular melalui kulit luka atau mukosa dengan air/tanah tercemar leptospira dariurine binatang. Kabupaten Bantul merupakan daerah endemis leptospirosis,case fatality rate mencapai11% pada tahun2010. Penelitian ini bertujuan ingin mengetahui persebaran epidemiologi spasial leptospirosis, dan pemetaanmodel daerah rawan Leptospirosisdi Kabupaten Bantul berdasarkan faktor risiko lingkungan dan trap success tikus dengan aplikasi Sistem Informasi Geografis. Penelitian ini dilakukanpada Bulan Maret sampaiNovember 2011, menggunakan metode analisis spasial deskriptif dengan pendekatan potong lintang. Hasil: Kasus leptospirosispada tahun2011 mencapai135 kasusyang didominasi oleh

  10. A mental model for successful inter-disciplinary collaboration in curriculum innovation for information literacy

    Directory of Open Access Journals (Sweden)

    M. Detken Scheepers

    2011-01-01

    Full Text Available The University of Pretoria introduced a compulsory Information Literacy module to address the need for delivering motivated knowledgeable employees that embrace information and have the skills to find, select and use relevant information accurately, efficiently and effectively in an explosive information age. Low class attendance, an indication of unmotivated students, as well as the limited scholarly application of information literacy skills in consecutive academic years of study have been identified as possible barriers to the application of the desired skills. A collaborative action research project based on Whole Brain principles was introduced to motivate learners through innovative learning material in the module. A deeper understanding of the role of thinking preferences and thinking avoidances is essential in selecting a team that is responsible for the planning, design, development and delivery of learning opportunities and material. This article discusses the Whole Brain Model® as a mental model that underpins the successful collaboration of multidisciplinary teams and enhances innovative curriculum design that addresses alternative approaches to the teaching of Information Literacy.

  11. Conceptual Model of Successful Educational online Community of Practice for Kingdom of Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Fatimah Al-Shahrani

    2014-10-01

    Full Text Available The community of practice is an internet application that nourishes knowledge management and innovation. Implementing the community of practice in education can enhance the learning process and make it an enjoyable, exiting and lifelong experience. In this paper, the researchers intend to create a conceptual model for the successful implementation of community of practice in Education in the Kingdom of Saudi Arabia through evaluate the literature review about the educational community of practice. Then, a prototype is developed followed by a survey to collect feed-backs about the experiment. Using the Chi-Square statistical method of qualitative analysis associated with the Design Science Methodology of research, the research is fulfilled. The results illustrated the conceptual model of the effective implementation of the community of practice in the Kingdom of Saudi Arabia, that define the seven factors to be considered which are network density, culture perceptions, distributed production, knowledge complexity and richness, government enforcement, IT specialist role, and senior members role.

  12. Analysis of behavioral intention on ABC system adoption: Model of information systems technology and success acceptance

    Directory of Open Access Journals (Sweden)

    Baiq Nensi Veni Indipenrian

    2015-12-01

    Full Text Available This study aims to examine the effect of individual behavioral change on the adoption of activity- based costing (ABC system and its usage, using Unified Theory of Accep-tance and Use of Technology (UTAUT and Information System Success Model. The sample involves 78 respondents who have positions as financial manager, controller manager, accounting manager, and production manager in mid-sized manufacturing companies in East java. The data were collected by survey method. This study used a Partial Least Square (PLS as the data analysis method. It was found that not all of the main UTAUT models were supported, because performance expectancy and effort expectancy have no effect on behavioral intention and use behavior to adopt ABC system. Whereas, social factors, information quality and facilitating conditions had a positive effect on behavioral intention and use behavior to adopt ABC system. The different results of this study with several previous studies are probably caused by the differences in the context of system, culture and characteristics of the sample. The implication of this study is not only to propose a theoretical framework for researches in future, but also useful for companies to optimize the use of ABC system that should be supported by top level and mid-level management and the readiness of the individu-als to accept the adoption of the ABC system.

  13. The Model for Understanding Success in Quality (MUSIQ): building a theory of context in healthcare quality improvement.

    Science.gov (United States)

    Kaplan, Heather C; Provost, Lloyd P; Froehle, Craig M; Margolis, Peter A

    2012-01-01

    BACKGROUND Quality improvement (QI) efforts have become widespread in healthcare, however there is significant variability in their success. Differences in context are thought to be responsible for some of the variability seen. To develop a conceptual model that can be used by organisations and QI researchers to understand and optimise contextual factors affecting the success of a QI project. 10 QI experts were provided with the results of a systematic literature review and then participated in two rounds of opinion gathering to identify and define important contextual factors. The experts subsequently met in person to identify relationships among factors and to begin to build the model. The Model for Understanding Success in Quality (MUSIQ) is organised based on the level of the healthcare system and identifies 25 contextual factors likely to influence QI success. Contextual factors within microsystems and those related to the QI team are hypothesised to directly shape QI success, whereas factors within the organisation and external environment are believed to influence success indirectly. The MUSIQ framework has the potential to guide the application of QI methods in healthcare and focus research. The specificity of MUSIQ and the explicit delineation of relationships among factors allows a deeper understanding of the mechanism of action by which context influences QI success. MUSIQ also provides a foundation to support further studies to test and refine the theory and advance the field of QI science.

  14. Structural Model of the Effect of Psychological Capital on Success with Due to the Mediating Role of Commitment and Satisfaction

    Directory of Open Access Journals (Sweden)

    M Golparvar

    2016-09-01

    Full Text Available This research was administered with the aim of investigating structural model of the effect of psychological capital on career success with due to the mediating role of satisfaction and commitment among employees of Telecom Company. Research statistical population was male and female employees of Telecom in Isfahan city, who among them two hundred and eighty five persons were selected using convenience sampling. Research instruments were Nguyen et al. Psychological Capital questionnaire, Nabi Job Success (career success Questionnaire, Spector Job Satisfaction Questionnaire and Speier and Venkatesh Organizational Commitment Questionnaire. Data were analyzed using structural equation modeling. Results of structural equation modeling revealed thatin aseriesof sequential relationships, there is a significant effect from psychological capital also on job satisfaction and organizational commitment and there is a significant effect also from job satisfaction and organizational commitment on job success (career success. The results also showed that psychological capital impact on career success was indirectly through job satisfaction and organizational commitment. Overall, the results of this study showed that job satisfaction and organizational commitment were mediating variables in the relationship between psychological capital and career success.

  15. Culture Matters in Successful Curriculum Change: An International Study of the Influence of National and Organizational Culture Tested With Multilevel Structural Equation Modeling.

    Science.gov (United States)

    Jippes, Mariëlle; Driessen, Erik W; Broers, Nick J; Majoor, Gerard D; Gijselaers, Wim H; van der Vleuten, Cees P M

    2015-07-01

    National culture has been shown to play a role in curriculum change in medical schools, and business literature has described a similar influence of organizational culture on change processes in organizations. This study investigated the impact of both national and organizational culture on successful curriculum change in medical schools internationally. The authors tested a literature-based conceptual model using multilevel structural equation modeling. For the operationalization of national and organizational culture, the authors used Hofstede's dimensions of culture and Quinn and Spreitzer's competing values framework, respectively. To operationalize successful curriculum change, the authors used two derivates: medical schools' organizational readiness for curriculum change developed by Jippes and colleagues, and change-related behavior developed by Herscovitch and Meyer. The authors administered a questionnaire in 2012 measuring the described operationalizations to medical schools in the process of changing their curriculum. Nine hundred ninety-one of 1,073 invited staff members from 131 of 345 medical schools in 56 of 80 countries completed the questionnaire. An initial poor fit of the model improved to a reasonable fit by two suggested modifications which seemed theoretically plausible. In sum, characteristics of national culture and organizational culture, such as a certain level of risk taking, flexible policies and procedures, and strong leadership, affected successful curriculum change. National and organizational culture influence readiness for change in medical schools. Therefore, medical schools considering curriculum reform should anticipate the potential impact of national and organizational culture.

  16. Incumbent Decisions about Succession Transitions in Family Firms: A Conceptual Model

    Directory of Open Access Journals (Sweden)

    Britta Boyd

    2014-11-01

    Full Text Available In the family business literature, succession research has focused on the family member as they enter the leadership role or on the different issues that affect the succession process. Although researchers have acknowledged that succession in family businesses is “punctuated” by decision making events, less attention has been given to understanding how incumbents make decisions about ownership and management transitions. In an effort to continue to understand the succession process it is important to understand how incumbents make decisions about the type of transitions they intend to engage in (i.e., intra-family succession, out of family succession, or no succession. Building on the theory of planned behavior and the socioemotional wealth framework (SEW, this manuscript presents a conceptual framework to understand the factors that influence succession transitions and the role that contextual factors can play in this decision-making process. We present theory driven propositions and discuss the implications for understanding and evaluation of the succession process.

  17. Developing a theoretical model and questionnaire survey instrument to measure the success of electronic health records in residential aged care.

    Science.gov (United States)

    Yu, Ping; Qian, Siyu

    2018-01-01

    Electronic health records (EHR) are introduced into healthcare organizations worldwide to improve patient safety, healthcare quality and efficiency. A rigorous evaluation of this technology is important to reduce potential negative effects on patient and staff, to provide decision makers with accurate information for system improvement and to ensure return on investment. Therefore, this study develops a theoretical model and questionnaire survey instrument to assess the success of organizational EHR in routine use from the viewpoint of nursing staff in residential aged care homes. The proposed research model incorporates six variables in the reformulated DeLone and McLean information systems success model: system quality, information quality, service quality, use, user satisfaction and net benefits. Two variables training and self-efficacy were also incorporated into the model. A questionnaire survey instrument was designed to measure the eight variables in the model. After a pilot test, the measurement scale was used to collect data from 243 nursing staff members in 10 residential aged care homes belonging to three management groups in Australia. Partial least squares path modeling was conducted to validate the model. The validated EHR systems success model predicts the impact of the four antecedent variables-training, self-efficacy, system quality and information quality-on the net benefits, the indicator of EHR systems success, through the intermittent variables use and user satisfaction. A 24-item measurement scale was developed to quantitatively evaluate the performance of an EHR system. The parsimonious EHR systems success model and the measurement scale can be used to benchmark EHR systems success across organizations and units and over time.

  18. The Analysis of Electronic Journal Utilization In Learning Process: Technology Acceptance Model And Information System Success

    Directory of Open Access Journals (Sweden)

    Achmad Zaky

    2017-12-01

    Full Text Available This study aims to observe the behavior of electronic journal (e-journal among bachelor students of the Universitas Brawijaya by Technology Acceptance Model (TAM and Information System Success (ISS as theoretical framework. The research samples are all bachelor students who have used e-journal in their learning process. The respondents are selected by convenience sampling method. The data are collected through survey and analyzed by Partial Least Square (PLS with SmartPLS 3. The result of the study reveals that user satisfaction and intention to use have significant effect on actual use of e-journal among bachelor students at the Universitas Brawijaya. Those variables affect the actual use because they have been formed by other variables such as information quality, perceived easiness, perceived usefulness, and attitude towards behavior. Furthermore, information quality has significant influence on user satisfaction, while perceived usefulness and perceived usefulness do not have direct effect on the intention to use. The implication of this study is relevant for educators to recognize the reason factors to use e-journal in the learning process.

  19. Going Mobile: An Empirical Model for Explaining Successful Information Logistics in Ward Rounds.

    Science.gov (United States)

    Esdar, Moritz; Liebe, Jan-David; Babitsch, Birgit; Hübner, Ursula

    2018-01-01

    Medical ward rounds are critical focal points of inpatient care that call for uniquely flexible solutions to provide clinical information at the bedside. While this fact is undoubted, adoption rates of mobile IT solutions remain rather low. Our goal was to investigate if and how mobile IT solutions influence successful information provision at the bedside, i.e. clinical information logistics, as well as to shed light at socio-organizational factors that facilitate adoption rates from a user-centered perspective. Survey data were collected from 373 medical and nursing directors of German, Austrian and Swiss hospitals and analyzed using variance-based Structural Equation Modelling (SEM). The adoption of mobile IT solutions explains large portions of clinical information logistics and is in itself associated with an organizational culture of innovation and end user participation. Results should encourage decision makers to understand mobility as a core constituent of information logistics and thus to promote close end-user participation as well as to work towards building a culture of innovation.

  20. Alberta Healthy Living Program--a model for successful integration of chronic disease management services.

    Science.gov (United States)

    Morrin, Louise; Britten, Judith; Davachi, Shahnaz; Knight, Holly

    2013-08-01

    The most common presentation of chronic disease is multimorbidity. Disease management strategies are similar across most chronic diseases. Given the prevalence of multimorbidity and the commonality in approaches, fragmented single disease management must be replaced with integrated care of the whole person. The Alberta Healthy Living Program, a community-based chronic disease management program, supports adults with, or at risk for, chronic disease to improve their health and well being. Participants gain confidence and skills in how to manage their chronic disease(s) by learning to understand their health condition, make healthy eating choices, exercise safely and cope emotionally. The program includes 3 service pillars: disease-specific and general health patient education, disease-spanning supervised exercise and Better Choices, Better Health(TM) self-management workshops. Services are delivered in the community by an interprofessional team and can be tailored to target specific diverse and vulnerable populations, such as Aboriginal, ethno-cultural and francophone groups and those experiencing homelessness. Programs may be offered as a partnership between Alberta Health Services, primary care and community organizations. Common standards reduce provincial variation in care, yet maintain sufficient flexibility to meet local and diverse needs and achieve equity in care. The model has been implemented successfully in 108 communities across Alberta. This approach is associated with reduced acute care utilization and improved clinical indicators, and achieves efficiencies through an integrated, disease-spanning patient-centred approach. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

  1. Toward establishing model organisms for marine protists: Successful transfection protocols for Parabodo caudatus (Kinetoplastida: Excavata).

    Science.gov (United States)

    Gomaa, Fatma; Garcia, Paulo A; Delaney, Jennifer; Girguis, Peter R; Buie, Cullen R; Edgcomb, Virginia P

    2017-09-01

    We developed protocols for, and demonstrated successful transfection of, the free-living kinetoplastid flagellate Parabodo caudatus with three plasmids carrying a fluorescence reporter gene (pEF-GFP with the EF1 alpha promoter, pUB-GFP with Ubiquitin C promoter, and pEYFP-Mitotrap with CMV promoter). We evaluated three electroporation approaches: (1) a square-wave electroporator designed for eukaryotes, (2) a novel microfluidic transfection system employing hydrodynamically-controlled electric field waveforms, and (3) a traditional exponential decay electroporator. We found the microfluidic device provides a simple and efficient platform to quickly test a wide range of electric field parameters to find the optimal set of conditions for electroporation of target species. It also allows for processing large sample volumes (>10 ml) within minutes, increasing throughput 100 times over cuvettes. Fluorescence signal from the reporter gene was detected a few hours after transfection and persisted for 3 days in cells transfected by pEF-GFP and pUB-GFP plasmids and for at least 5 days post-transfection for cells transfected with pEYFP-Mitotrap. Expression of the reporter genes (GFP and YFP) was also confirmed using reverse transcription-PCR (RT-PCR). This work opens the door for further efforts with this taxon and close relatives toward establishing model systems for genome editing. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  2. Developing and validating a model to predict the success of an IHCS implementation: the Readiness for Implementation Model

    Science.gov (United States)

    Gustafson, David H; Hawkins, Robert P; Brennan, Patricia F; Dinauer, Susan; Johnson, Pauley R; Siegler, Tracy

    2010-01-01

    Objective To develop and validate the Readiness for Implementation Model (RIM). This model predicts a healthcare organization's potential for success in implementing an interactive health communication system (IHCS). The model consists of seven weighted factors, with each factor containing five to seven elements. Design Two decision-analytic approaches, self-explicated and conjoint analysis, were used to measure the weights of the RIM with a sample of 410 experts. The RIM model with weights was then validated in a prospective study of 25 IHCS implementation cases. Measurements Orthogonal main effects design was used to develop 700 conjoint-analysis profiles, which varied on seven factors. Each of the 410 experts rated the importance and desirability of the factors and their levels, as well as a set of 10 different profiles. For the prospective 25-case validation, three time-repeated measures of the RIM scores were collected for comparison with the implementation outcomes. Results Two of the seven factors, ‘organizational motivation’ and ‘meeting user needs,’ were found to be most important in predicting implementation readiness. No statistically significant difference was found in the predictive validity of the two approaches (self-explicated and conjoint analysis). The RIM was a better predictor for the 1-year implementation outcome than the half-year outcome. Limitations The expert sample, the order of the survey tasks, the additive model, and basing the RIM cut-off score on experience are possible limitations of the study. Conclusion The RIM needs to be empirically evaluated in institutions adopting IHCS and sustaining the system in the long term. PMID:20962135

  3. Is Russia successful in attracting foreign direct investment? Evidence based on gravity model estimation

    Directory of Open Access Journals (Sweden)

    Mariev Oleg

    2016-09-01

    Full Text Available The aim of this paper is twofold. First, it is to answer the question of whether Russia is successful in attracting foreign direct investment (FDI. Second, it is to identify partner countries that “overinvest” and “underinvest” in the Russian economy. We do this by calculating potential FDI inflows to Russia and comparing them with actual values. This research is associated with the empirical estimation of factors explaining FDI flows between countries. The methodological foundation used for the research is the gravity model of foreign direct investment. In discussing the pros and cons of different econometric methods of the estimation gravity equation, we conclude that the Poisson pseudo maximum likelihood method with instrumental variables (IV PPML is one of the best options in our case. Using a database covering about 70% of FDI flows for the period of 2001-2011, we discover the following factors that explain the variance of bilateral FDI flows in the world economy: GDP value of investing country, GDP value of recipient country, distance between countries, remoteness of investor country, remoteness of recipient country, level of institutions development in host country, wage level in host country, membership of two countries in a regional economic union, common official language, common border and colonial relationships between countries in the past. The potential values of FDI inflows are calculated using coefficients of regressors from the econometric model. We discover that the Russian economy performs very well in attracting FDI: the actual FDI inflows exceed potential values by 1.72 times. Large developed countries (France, Germany, UK, Italy overinvest in the Russian economy, while smaller and less developed countries (Czech Republic, Belarus, Denmark, Ukraine underinvest in Russia. Countries of Southeast Asia (China, South Korea, Japan also underinvest in the Russian economy.

  4. A South African public-private partnership HIV treatment model: viability and success factors.

    Science.gov (United States)

    Igumbor, Jude; Pascoe, Sophie; Rajap, Shuabe; Townsend, Wendy; Sargent, John; Darkoh, Ernest

    2014-01-01

    The increasing number of people requiring HIV treatment in South Africa calls for efficient use of its human resources for health in order to ensure optimum treatment coverage and outcomes. This paper describes an innovative public-private partnership model which uses private sector doctors to treat public sector patients and ascertains the model's ability to maintain treatment outcomes over time. The study used a retrospective design based on the electronic records of patients who were down-referred from government hospitals to selected private general medical practitioners (GPs) between November 2005 and October 2012. In total, 2535 unique patient records from 40 GPs were reviewed. The survival functions for mortality and attrition were calculated. Cumulative incidence of mortality for different time cohorts (defined by year of treatment initiation) was also established. The median number of patients per GP was 143 (IQR: 66-246). At the time of down-referral to private GPs, 13.8% of the patients had CD4 count private sector based programme can be effectively and efficiently used to either target specific health concerns, key populations or serve as a stop-gap measure to meet urgent health needs.

  5. Validation of mathematical models to describe fluid dynamics of a cold riser by gamma ray attenuation; Validacao de modelos matematicos para descrever a fluidodinamica de um riser utilizando atenuacao gama

    Energy Technology Data Exchange (ETDEWEB)

    Melo, Ana Cristina Bezerra Azedo de

    2004-12-15

    The fluid dynamic behavior of a riser in a cold type FCC model was investigated by means of catalyst concentration distribution measured with gamma attenuation and simulated with a mathematical model. In the riser of the cold model, MEF, 0,032 m in diameter, 2,30 m in length the fluidized bed, whose components are air and FCC catalyst, circulates. The MEF is operated by automatic control and instruments for measuring fluid dynamic variables. An axial catalyst concentration distribution was measured using an Am-241 gamma source and a NaI detector coupled to a multichannel provided with a software for data acquisition and evaluation. The MEF was adapted for a fluid dynamic model validation which describes the flow in the riser, for example, by introducing an injector for controlling the solid flow in circulation. Mathematical models were selected from literature, analyzed and tested to simulate the fluid dynamic of the riser. A methodology for validating fluid dynamic models was studied and implemented. The stages of the work were developed according to the validation methodology, such as data planning experiments, study of the equations which describe the fluidodynamic, computational solvers application and comparison with experimental data. Operational sequences were carried out keeping the MEF conditions for measuring catalyst concentration and simultaneously measuring the fluid dynamic variables, velocity of the components and pressure drop in the riser. Following this, simulated and experimental values were compared and statistical data treatment done, aiming at the required precision to validate the fluid dynamic model. The comparison tests between experimental and simulated data were carried out under validation criteria. The fluid dynamic behavior of the riser was analyzed and the results and the agreement with literature were discussed. The adopt model was validated under the MEF operational conditions, for a 3 to 6 m/s gas velocity in the riser and a slip

  6. Treatment of Events Representing System Success in Accident Sequences in PSA Models with ET/FT Linking

    International Nuclear Information System (INIS)

    Vrbanic, I.; Spiler, J.; Mikulicic, V.; Simic, Z.

    2002-01-01

    Treatment of events that represent systems' successes in accident sequences is well known issue associated primarily with those PSA models that employ event tree / fault tree (ET / FT) linking technique. Even theoretically clear, practical implementation and usage creates for certain PSA models a number of difficulties regarding result correctness. Strict treatment of success-events would require consistent applying of de Morgan laws. However, there are several problems related to it. First, Boolean resolution of the overall model, such as the one representing occurrence of reactor core damage, becomes very challenging task if De Morgan rules are applied consistently at all levels. Even PSA tools of the newest generation have some problems with performing such a task in a reasonable time frame. The second potential issue is related to the presence of negated basic events in minimal cutsets. If all the basic events that result from strict applying of De Morgan rules are retained in presentation of minimal cutsets, their readability and interpretability may be impaired severely. It is also worth noting that the concept of a minimal cutset is tied to equipment failures, rather than to successes. For reasons like these, various simplifications are employed in PSA models and tools, when it comes to the treatment of success-events in the sequences. This paper provides a discussion of major concerns associated with the treatment of success-events in accident sequences of a typical PSA model. (author)

  7. "Grey nomads" in Australia: are they a good model for successful aging and health?

    Science.gov (United States)

    Higgs, Paul F D; Quirk, Frances

    2007-10-01

    Lifestyle factors have been identified as being very important in determining health in later life. Nutrition, exercise, and social environment all interact to promote, or to limit, opportunities for an active and healthy post-working life. Not only are rates of chronic illness and disability reduced through the promotion of healthy lifestyles, but also quality of life is maintained through the compression of morbidity. Governments in Australia, as in the European Union and North America, have highlighted the importance of behavioral change in health promotion strategies with the aim of having an impact on the health-related lifestyles of their populations. This paper examines the example of a group of older Australians, the "grey nomads," who may present opportunities for examining health-related lifestyle changes. The term grey nomad refers to a portion of the older population in Australia who choose to use their later years and retirement as opportunities for travel and leisure, mainly within the confines of the Australian continent. As such, they are similar to groups in North America, such as the "snow birds," who travel to the southern United States to escape the colder winters of more northerly latitudes. Similar seasonal migrations occur from Northern to Southern Europe. What all share in common is an active culture/lifestyle of attempting to "age successfully." Grey nomads also participate in the creation of what can be termed postmodern communities, where they and other regular travelers may develop a sense of community feeling with others who are also regularly returning to the same spot year after year. Social support is highly predictive of health outcomes and such mobile communities may prove a positive factor in promoting good health. In this paper we examine whether the "grey nomads" represent a good model for improving health-related lifestyles in later life.

  8. Insights from the design and implementation of a single-entry model of referral for total joint replacement surgery: Critical success factors and unanticipated consequences.

    Science.gov (United States)

    Damani, Zaheed; MacKean, Gail; Bohm, Eric; Noseworthy, Tom; Wang, Jenney Meng Han; DeMone, Brie; Wright, Brock; Marshall, Deborah A

    2018-02-01

    Single-entry models (SEMs) in healthcare allow patients to see the next-available provider and have been shown to improve waiting times, access and patient flow for preference-sensitive, scheduled services. The Winnipeg Central Intake Service (WCIS) for hip and knee replacement surgery was implemented to improve access in the Winnipeg Regional Health Authority. This paper describes the system's design/implementation; successes, challenges, and unanticipated consequences. On two occasions, during and following implementation, we interviewed all members of the WCIS project team, including processing engineers, waiting list coordinators, administrators and policy-makers regarding their experiences. We used semi-structured telephone interviews to collect data and qualitative thematic analysis to analyze and interpret the findings. Respondents indicated that the overarching objectives of the WCIS were being met. Benefits included streamlined processes, greater patient access, improved measurement and monitoring of outcomes. Challenges included low awareness, change readiness, and initial participation among stakeholders. Unanticipated consequences included workload increases, confusion around stakeholder expectations and under-reporting of data by surgeons' offices. Critical success factors for implementation included a requirement for clear communication, robust data collection, physician leadership and patience by all, especially implementation teams. Although successfully implemented, key lessons and critical success factors were learned related to change management, which if considered and applied, can reduce unanticipated consequences, improve uptake and benefit new models of care. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. The organizational structure and group the following criteria in assessing the success of the model construction companies

    Directory of Open Access Journals (Sweden)

    Đurović Dušan D.

    2016-01-01

    Full Text Available The organization - an organizational structure presents a schedule of all the potential companies covering all human and material resources in the enterprise, which ensure the realization of business goals in function of their success. Defining the process, the use of SWOT analysis and evaluation of success using appropriate models condition and promote the role of the organization in a construction company. This article is an excerpt from the research within relevant doctoral dissertation [5] and displays the result of the evaluation of business performance of construction companies applying AHP model.

  10. ANALYSIS OF INFORMATION SYSTEM IMPLEMENTATION IN BINUS UNIVERSITY USING DELONE AND MCLEAN INFORMATION SYSTEM SUCCESS MODEL AND COBIT FRAMEWORK

    Directory of Open Access Journals (Sweden)

    Johan Muliadi Kerta

    2013-05-01

    Full Text Available The success of implementation of information system in an organization will supportthe organization in the process of achieving goals. Successful information system will support theorganization's day-to-day operations, so that problem can be resolved more quickly and easily. Theinformation system which has been developed and implemented is also necessary to measure thematurity level. Therefore, it can determine whether the implementation of information systemsmade in accordance with the goals of the organization. Measuring the success of informationsystems used the DeLone and McLean IS success model. To measure the maturity level ofinformation systems used COBIT (Control Objectives for Information and related Technologyframeworks that provides best practices for IT governance and control. The results of this analysiswill assist and support the IT team in order to develop and build information systems that better fitthe needs and goals of the organization.

  11. A mathematical model for describing the retinal nerve fiber bundle trajectories in the human eye: average course, variability, and influence of refraction, optic disc size and optic disc position.

    Science.gov (United States)

    Jansonius, Nomdo M; Schiefer, Julia; Nevalainen, Jukka; Paetzold, Jens; Schiefer, Ulrich

    2012-12-01

    Previously we developed a mathematical model for describing the retinal nerve fiber bundle trajectories in the superior-temporal and inferior-temporal regions of the human retina, based on traced trajectories extracted from fundus photographs. Aims of the current study were to (i) validate the existing model, (ii) expand the model to the entire retina and (iii) determine the influence of refraction, optic disc size and optic disc position on the trajectories. A new set of fundus photographs was collected comprising 28 eyes of 28 subjects. From these 28 photographs, 625 trajectories were extracted. Trajectories in the temporal region of the retina were compared to the existing model. In this region, 347 of 399 trajectories (87%) were within the 95% central range of the existing model. The model was extended to the nasal region. With this extension, the model can now be applied to the entire retina that corresponds to the visual field as tested with standard automated perimetry (up to approximately 30° eccentricity). There was an asymmetry between the superior and inferior hemifields and a considerable location-specific inter-subject variability. In the nasal region, we found two "singularities", located roughly at the one and five o'clock positions for the right optic disc. Here, trajectories from relatively widespread areas of the retina converge. Associations between individual deviations from the model and refraction, optic disc size and optic disc position were studied with multiple linear regression. Refraction (P = 0.021) and possibly optic disc inclination (P = 0.09) influenced the trajectories in the superior-temporal region. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Supporting good practice in the provision of services to people with comorbid mental health and alcohol and other drug problems in Australia: describing key elements of good service models

    Directory of Open Access Journals (Sweden)

    Canaway Rachel

    2010-12-01

    Full Text Available Abstract Background The co-occurrence of mental illness and substance use problems (referred to as "comorbidity" in this paper is common, and is often reported by service providers as the expectation rather than the exception. Despite this, many different treatment service models are being used in the alcohol and other drugs (AOD and mental health (MH sectors to treat this complex client group. While there is abundant literature in the area of comorbidity treatment, no agreed overarching framework to describe the range of service delivery models is apparent internationally or at the national level. The aims of the current research were to identify and describe elements of good practice in current service models of treatment of comorbidity in Australia. The focus of the research was on models of service delivery. The research did not aim to measure the client outcomes achieved by individual treatment services, but sought to identify elements of good practice in services. Methods Australian treatment services were identified to take part in the study through a process of expert consultation. The intent was to look for similarities in the delivery models being implemented across a diverse set of services that were perceived to be providing good quality treatment for people with comorbidity problems. Results A survey was designed based on a concept map of service delivery devised from a literature review. Seventeen Australian treatment services participated in the survey, which explored the context in which services operate, inputs such as organisational philosophy and service structure, policies and procedures that guide the way in which treatment is delivered by the service, practices that reflect the way treatment is provided to clients, and client impacts. Conclusions The treatment of people with comorbidity of mental health and substance use disorders presents complex problems that require strong but flexible service models. While the treatment

  13. THE SECRET TO BUSINESS SUCCESS AFTER THE CRISIS A BUSINESS MODEL IN AN ENTERPRISE

    OpenAIRE

    Kozma, Tímea; Gyenge, Balázs

    2015-01-01

    Many scientific researches look for and study the success factors of businesses. (Colins, 2001; Móricz 2009; Osterwalder-Pigneur 2002:3; Chesbrough-Rosenbloom 2002:535; Casadesus-Masanell-Ricart 2008; Stähler 2002:6; ) After the economic crisis of 2008, attention has especially drawn to those businesses which successfully survived the previous hard times, probably due to their “best practices”. In addition to internal resources, the external environment effects taking place outside the walls ...

  14. Clearing the air: Alberta a model of success in decreasing venting, flaring

    International Nuclear Information System (INIS)

    Harrison, L.

    2004-01-01

    An historical review of flaring and venting in the Alberta oilfields is presented. The story begins with gas production in the Turner Valley, Alberta in 1931, Western Canada's first, largest and most productive source of oil and naphtha until the discovery of Leduc in 1947. Gas production at Turner Valley reached 500 mmcf per day, of which about 486 mmcf was flared. Through the efforts of the Alberta Energy and Utilities Board (EUB) and its predecessors venting and flaring was drastically cut, to the point where in 2003 the World Bank Group, an agency of the United Nations, approached the EUB to present the Alberta flaring and venting reduction model to developing countries. Accordingly, a Flaring Workshop was held at Calgary in October 2003, attended by delegates from Algeria, Angola, Cameroon, Indonesia and Nigeria. The article also details the EUB's requirements for upstream flaring in Alberta, as laid down in 'Guide 60'. The draft Guide was released in January 2003, the final draft is targeted for February 2004. In brief, the Guide requires operators, by means of a 'decision tree analysis' method which is described in the Guide, to evaluate whether it is possible to reduce or eliminate flaring and venting; it also requires operators to evaluate economic feasibility, and to determine the feasibility of conserving as much gas as possible. New developments in the field of sensors, controls and optical flow meters are also reviewed. An appended statistical summary of gas flaring trends in selected countries, compiled by the World Bank in 2000 shows Nigeria, Iran, Russia, Algeria and Mexico as the countries with the highest volumes of flaring. To give an indication of the volume of gas wasted through flaring, it is reliably estimated that the amount of gas flared in 2000 by African countries alone, could have fuelled power plants to generate sufficient electric power to meet fully half of the continent's needs for electric power. 1 tab., 2 figs

  15. A conceptual model of individual competency components as one of the predictors of success in mergers and acquisitions

    Directory of Open Access Journals (Sweden)

    Darko Kovač

    2008-12-01

    Full Text Available The increasing challenge of how to balance “soft” human factors with “hard” financial factors in mergers and acquisitions (M&A to be successful is not new. However, the real challenge lies in the question of how, and with which yardstick, to measure and compare the human factor in both the acquiring and the acquired companies in all phases of M&A. In this study, a model for measuring and comparing the human factor with competencies is presented. The model enables the measuring of soft factors with quantitative criteria. A tripartite individual competency components construct is conceived: cognitive, affective and conative, to which the personal value system is added. The model discussed is based on empirical findings and the cases of two companies and literature. The model enables companies to compare differences in competencies and thus to plan activities how to overcome those differences and achieve a higher success rate in M&A.

  16. A Model Midshipman: Factors Related to Academic and Military Success of Prior Enlisted Midshipmen at the United States Naval Academy

    National Research Council Canada - National Science Library

    Wyrick, Jared

    2005-01-01

    ... to be successful at the Naval Academy. Linear and Bi-Linear regression models are used to analyze the influence of prior-enlisted experience on academic and military performance at the Naval Academy on the classes from 1999 through 2004...

  17. Effect of 5E Instructional Model in Student Success in Primary School 6th Year Circulatory System Topic

    Science.gov (United States)

    Cardak, Osman; Dikmenli, Musa; Saritas, Ozge

    2008-01-01

    The aim of this study is to research the effect of the 5E instructional model on primary (sixth grade) student success during the circulatory system unit. This study was conducted with 38 students in two different classes by the same researcher in 2006-2007. One of the classes was assigned as the control group and the other as the experimental…

  18. What makes a sustainable business model successful? : An empirical comparison of two peer-to-peer goods-sharing platforms

    NARCIS (Netherlands)

    Piscicelli, Laura; Ludden, Geke D.S.; Cooper, Tim

    2018-01-01

    Sustainable business models are intended to create economic value while benefitting the environment and society. Their wider adoption and diffusion is necessary to tackle pressing societal problems. How they are implemented and what determines their success (or lack thereof) in the market is not yet

  19. A Path Analysis Model Pertinent to Undergraduates' Academic Success: Examining Academic Confidence, Psychological Capital and Academic Coping Factors

    Science.gov (United States)

    Kirikkanat, Berke; Soyer, Makbule Kali

    2018-01-01

    The major purpose of this study was to create a path analysis model of academic success in a group of university students, which included the variables of academic confidence and psychological capital with a mediator variable--academic coping. 400 undergraduates from Marmara University and Istanbul Commerce University who were in sophomore, junior…

  20. Electoral Entry and Success of Ethnic Minority Parties in Central and Eastern Europe: A Hierarchical Selection Model

    DEFF Research Database (Denmark)

    Bernauer, Julian; Bochsler, Daniel

    2011-01-01

    and electoral demand, measured here as the size of ethnic groups and the saliency of ethnic issues. In line with these expectations, parties only run if they can expect electoral support sufficient to pass the electoral threshold. This finding would have been overlooked by a na??ve model of electoral success...... which does not take self-selection into account. ?? 2011 Elsevier Ltd....