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Sample records for models provide critical

  1. Relationship between anaerobic parameters provided from MAOD and critical power model in specific table tennis test.

    Science.gov (United States)

    Zagatto, A M; Gobatto, C A

    2012-08-01

    The aim of this study was to verify the validity of the curvature constant parameter (W'), calculated from 2-parameter mathematical equations of critical power model, in estimating the anaerobic capacity and anaerobic work capacity from a table tennis-specific test. Specifically, we aimed to i) compare constants estimated from three critical intensity models in a table tennis-specific test (Cf); ii) correlate each estimated W' with the maximal accumulated oxygen deficit (MAOD); iii) correlate each W' with the total amount of anaerobic work (W ANAER) performed in each exercise bout performed during the Cf test. Nine national-standard male table tennis players participated in the study. MAOD was 63.0(10.8) mL · kg - 1 and W' values were 32.8(6.6) balls for the linear-frequency model, 38.3(6.9) balls for linear-total balls model, 48.7(8.9) balls for Nonlinear-2 parameter model. Estimated W' from the Nonlinear 2-parameter model was significantly different from W' from the other 2 models (P0.13). Thus, W' estimated from the 2-parameter mathematical equations did not correlate with MAOD or W ANAER in table tennis-specific tests, indicating that W' may not provide a strong and valid estimation of anaerobic capacity and anaerobic capacity work. © Georg Thieme Verlag KG Stuttgart · New York.

  2. A Critical Subset Model Provides a Conceptual Basis for the High Antiviral Activity of Major HIV Drugs**

    Science.gov (United States)

    Shen, Lin; Rabi, S. Alireza; Sedaghat, Ahmad R.; Shan, Liang; Lai, Jun; Xing, Sifei; Siliciano, Robert F.

    2012-01-01

    Control of HIV-1 replication was first achieved with regimens that included a nonnucleoside reverse transcriptase inhibitor (NNRTI) or a protease inhibitor (PI); however, an explanation for the high antiviral activity of these drugs has been lacking. Indeed, conventional pharmacodynamic measures like IC50 (drug concentration causing 50% inhibition) do not differentiate NNRTIs and PIs from less active nucleoside reverse transcriptase inhibitors (NRTIs). Drug inhibitory potential depends on the slope of the dose-response curve (m), which represents how inhibition increases as a function of increasing drug concentration and is related to the Hill coefficient, a measure of intramolecular cooperativity in ligand binding to a multivalent receptor. Although NNRTIs and PIs bind univalent targets, they unexpectedly exhibit cooperative dose-response curves (m > 1). We show that this cooperative inhibition can be explained by a model in which infectivity requires participation of multiple copies of a drug target in an individual life cycle stage. A critical subset of these target molecules must be in the unbound state. Consistent with experimental observations, this model predicts m > 1 for NNRTIs and PIs and m = 1 in situations where a single drug target/virus mediates a step in the life cycle, as is the case with NRTIs and integrase strand transfer inhibitors. This model was tested experimentally by modulating the number of functional drug targets per virus, and dose-response curves for modulated virus populations fit model predictions. This model explains the high antiviral activity of two drug classes important for successful HIV-1 treatment and defines a characteristic of good targets for antiviral drugs in general, namely, intermolecular cooperativity. PMID:21753122

  3. Providing care for critically ill surgical patients: challenges and recommendations.

    Science.gov (United States)

    Tisherman, Samuel A; Kaplan, Lewis; Gracias, Vicente H; Beilman, Gregory J; Toevs, Christine; Byrnes, Matthew C; Coopersmith, Craig M

    2013-07-01

    Providing optimal care for critically ill and injured surgical patients will become more challenging with staff shortages for surgeons and intensivists. This white paper addresses the historical issues behind the present situation, the need for all intensivists to engage in dedicated critical care per the intensivist model, and the recognition that intensivists from all specialties can provide optimal care for the critically ill surgical patient, particularly with continuing involvement by the surgeon of record. The new acute care surgery training paradigm (including trauma, surgical critical care, and emergency general surgery) has been developed to increase interest in trauma and surgical critical care, but the number of interested trainees remains too few. Recommendations are made for broadening the multidisciplinary training and practice opportunities in surgical critical care for intensivists from all base specialties and for maintaining the intensivist model within acute care surgery practice. Support from academic and administrative leadership, as well as national organizations, will be needed.

  4. Providing Nuclear Criticality Safety Analysis Education through Benchmark Experiment Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess; J. Blair Briggs; David W. Nigg

    2009-11-01

    One of the challenges that today's new workforce of nuclear criticality safety engineers face is the opportunity to provide assessment of nuclear systems and establish safety guidelines without having received significant experience or hands-on training prior to graduation. Participation in the International Criticality Safety Benchmark Evaluation Project (ICSBEP) and/or the International Reactor Physics Experiment Evaluation Project (IRPhEP) provides students and young professionals the opportunity to gain experience and enhance critical engineering skills.

  5. Criticism and Counter-Criticism of Public Management: Strategy Models

    OpenAIRE

    Luis C. Ortigueira

    2007-01-01

    Critical control is very important in scientific management. This paper presents models of critical and counter-critical public-management strategies, focusing on the types of criticism and counter-criticism manifested in parliamentary political debates. The paper includes: (i) a normative model showing how rational criticism can be carried out; (ii) a normative model for oral critical intervention; and (iii) a general motivational strategy model for criticisms and counter-criticisms. The pap...

  6. Critical care providers' opinion on unsafe abortion in Argentina.

    Science.gov (United States)

    Vasquez, Daniela N; Das Neves, Andrea V; Golubicki, José L; Di Marco, Ingrid; Loudet, Cecilia I; Roberti, Javier E; Palacios-Jaraquemada, Jose; Basualdo, Natalia; Varaglia, Ruben; Vidal, Laura

    2012-03-01

    To survey the opinion of critical care providers in Argentina about abortion. An anonymous questionnaire was distributed to critical care providers attending the 20th National Critical Care Conference in Argentina. 149 of 1800 attendees completed the questionnaire, 69 (46.3%) of whom were members of the Argentine Society of Critical Care (ASCC). 122 (81.9%) supported abortion decriminalization in situations excluded from the current law; 142 (95.3%) in cases of congenital defects; 133 (89.3%) in cases of rape; 115 (77.2%) when women's mental health is at risk; 71 (47.7%) when pregnancy is unintended; and 61 (40.9%) for economic reasons. 126 (84.6%) supported abortion in public and private institutions, and 121 (81.2%) before 12 weeks of pregnancy. Variables independently associated with abortion support among female versus male attendees were abortion to preserve women's mental health (OR 4.47; 95% CI, 1.61-12.42; P=0.004) and abortion before 12 weeks of pregnancy (OR 3.93; 95% CI, 1.29-11.94; P=0.015). Abortion at request was independently associated with ASCC membership (OR 2.63; 95% CI, 1.07-6.45; P=0.034). Critical care providers would support abortion in situations excluded from the current abortion law and before 12 weeks of pregnancy, in both public and private hospitals. Copyright © 2011 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  7. The Teacher as Model Critic

    Science.gov (United States)

    Feldman, Edmund B.

    1973-01-01

    Article is organized around five questions: what is art criticism, its relationship to education, its connection with art education, and can criticism be taught, and what does a teacher need in order to function as a model of criticism? (Author/RK)

  8. Criticality experiments to provide benchmark data on neutron flux traps

    International Nuclear Information System (INIS)

    Bierman, S.R.

    1988-06-01

    The experimental measurements covered by this report were designed to provide benchmark type data on water moderated LWR type fuel arrays containing neutron flux traps. The experiments were performed at the US Department of Energy Hanford Critical Mass Laboratory, operated by Pacific Northwest Laboratory. The experimental assemblies consisted of 2 /times/ 2 arrays of 4.31 wt % 235 U enriched UO 2 fuel rods, uniformly arranged in water on a 1.891 cm square center-to-center spacing. Neutron flux traps were created between the fuel units using metal plates containing varying amounts of boron. Measurements were made to determine the effect that boron loading and distance between the fuel and flux trap had on the amount of fuel required for criticality. Also, measurements were made, using the pulse neutron source technique, to determine the effect of boron loading on the effective neutron multiplications constant. On two assemblies, reaction rate measurements were made using solid state track recorders to determine absolute fission rates in 235 U and 238 U. 14 refs., 12 figs., 7 tabs

  9. A critical review of clarifier modelling

    DEFF Research Database (Denmark)

    Plósz, Benedek; Nopens, Ingmar; Rieger, Leiv

    This outline paper aims to provide a critical review of secondary settling tank (SST) modelling approaches used in current wastewater engineering and develop tools not yet applied in practice. We address the development of different tier models and experimental techniques in the field with a part...

  10. Blood Products Provided to Patients Receiving Futile Critical Care.

    Science.gov (United States)

    Neville, Thanh H; Ziman, Alyssa; Wenger, Neil S

    2017-09-01

    The number of hospitalized patients receiving treatment perceived to be futile is not insignificant. Blood products are valuable resources that are donated to help others in need. We aimed to quantify the amount of blood transfused into patients who were receiving treatment that the critical care physician treating them perceived to be futile. During a 3-month period, critical care physicians in 5 adult intensive care units completed a daily questionnaire to identify patients perceived as receiving futile treatment. Of 1136 critically ill patients, physicians assessed 123 patients (11%) as receiving futile treatment. Fifty-nine (48%) of the 123 patients received blood products after they were assessed to be receiving futile treatment: 242 units of packed red blood cells (PRBCs) (7.6% of all PRBC units transfused into critical care patients during the 3-month study period); 161 (9.9%) units of plasma, 137 (12.1%) units of platelets, and 21 (10.5%) units of cryoprecipitate. Explicit guidelines on the use of blood products should be developed to ensure that the use of this precious resource achieves meaningful goals. © 2017 Society of Hospital Medicine.

  11. Conserving critical sites for biodiversity provides disproportionate benefits to people

    DEFF Research Database (Denmark)

    Larsen, Frank Wugt; Turner, Will R.; Brooks, Thomas M.

    2012-01-01

    Protecting natural habitats in priority areas is essential to halt the loss of biodiversity. Yet whether these benefits for biodiversity also yield benefits for human well-being remains controversial. Here we assess the potential human well-being benefits of safeguarding a global network of sites......) benefits to maintenance of human cultural diversity - significantly exceeding those anticipated from randomly selected sites within the same countries and ecoregions. Results suggest that safeguarding sites important for biodiversity conservation provides substantial benefits to human well-being....

  12. Conserving critical sites for biodiversity provides disproportionate benefits to people.

    Directory of Open Access Journals (Sweden)

    Frank W Larsen

    Full Text Available Protecting natural habitats in priority areas is essential to halt the loss of biodiversity. Yet whether these benefits for biodiversity also yield benefits for human well-being remains controversial. Here we assess the potential human well-being benefits of safeguarding a global network of sites identified as top priorities for the conservation of threatened species. Conserving these sites would yield benefits--in terms of a climate change mitigation through avoidance of CO(2 emissions from deforestation; b freshwater services to downstream human populations; c retention of option value; and d benefits to maintenance of human cultural diversity--significantly exceeding those anticipated from randomly selected sites within the same countries and ecoregions. Results suggest that safeguarding sites important for biodiversity conservation provides substantial benefits to human well-being.

  13. Conserving Critical Sites for Biodiversity Provides Disproportionate Benefits to People

    Science.gov (United States)

    Larsen, Frank W.; Turner, Will R.; Brooks, Thomas M.

    2012-01-01

    Protecting natural habitats in priority areas is essential to halt the loss of biodiversity. Yet whether these benefits for biodiversity also yield benefits for human well-being remains controversial. Here we assess the potential human well-being benefits of safeguarding a global network of sites identified as top priorities for the conservation of threatened species. Conserving these sites would yield benefits – in terms of a) climate change mitigation through avoidance of CO2 emissions from deforestation; b) freshwater services to downstream human populations; c) retention of option value; and d) benefits to maintenance of human cultural diversity – significantly exceeding those anticipated from randomly selected sites within the same countries and ecoregions. Results suggest that safeguarding sites important for biodiversity conservation provides substantial benefits to human well-being. PMID:22666337

  14. Critical care providers refer to information tools less during communication tasks after a critical care clinical information system introduction.

    Science.gov (United States)

    Ballermann, Mark; Shaw, Nicola T; Mayes, Damon C; Gibney, R T Noel

    2011-01-01

    Electronic documentation methods may assist critical care providers with information management tasks in Intensive Care Units (ICUs). We conducted a quasi-experimental observational study to investigate patterns of information tool use by ICU physicians, nurses, and respiratory therapists during verbal communication tasks. Critical care providers used tools less at 3 months after the CCIS introduction. At 12 months, care providers referred to paper and permanent records, especially during shift changes. The results suggest potential areas of improvement for clinical information systems in assisting critical care providers in ensuring informational continuity around their patients.

  15. Systems modeling and simulation applications for critical care medicine.

    Science.gov (United States)

    Dong, Yue; Chbat, Nicolas W; Gupta, Ashish; Hadzikadic, Mirsad; Gajic, Ognjen

    2012-06-15

    Critical care delivery is a complex, expensive, error prone, medical specialty and remains the focal point of major improvement efforts in healthcare delivery. Various modeling and simulation techniques offer unique opportunities to better understand the interactions between clinical physiology and care delivery. The novel insights gained from the systems perspective can then be used to develop and test new treatment strategies and make critical care delivery more efficient and effective. However, modeling and simulation applications in critical care remain underutilized. This article provides an overview of major computer-based simulation techniques as applied to critical care medicine. We provide three application examples of different simulation techniques, including a) pathophysiological model of acute lung injury, b) process modeling of critical care delivery, and c) an agent-based model to study interaction between pathophysiology and healthcare delivery. Finally, we identify certain challenges to, and opportunities for, future research in the area.

  16. The Biomantle-Critical Zone Model

    Science.gov (United States)

    Johnson, D. L.; Lin, H.

    2006-12-01

    It is a fact that established fields, like geomorphology, soil science, and pedology, which treat near surface and surface processes, are undergoing conceptual changes. Disciplinary self examinations are rife. New practitioners are joining these fields, bringing novel and interdisciplinary ideas. Such new names as "Earth's critical zone," "near surface geophysics," and "weathering engine" are being coined for research groups. Their agendas reflect an effort to integrate and reenergize established fields and break new ground. The new discipline "hydropedology" integrates soil science with hydrologic principles, and recent biodynamic investigations have spawned "biomantle" concepts and principles. One force behind these sea shifts may be retrospectives whereby disciplines periodically re-invent themselves to meet new challenges. Such retrospectives may be manifest in the recent Science issue on "Soils, The Final Frontier" (11 June, 2004), and in recent National Research Council reports that have set challenges to science for the next three decades (Basic Research Opportunities in Earth Science, and Grand Challenges for the Environmental Sciences, both published in 2001). In keeping with such changes, we advocate the integration of biomantle and critical zone concepts into a general model of Earth's soil. (The scope of the model automatically includes the domain of hydropedology.) Our justification is that the integration makes for a more appealing holistic, and realistic, model for the domain of Earth's soil at any scale. The focus is on the biodynamics of the biomantle and water flow within the critical zone. In this general model the biomantle is the epidermis of the critical zone, which extends to the base of the aquifer. We define soil as the outer layer of landforms on planets and similar bodies altered by biological, chemical, and/or physical agents. Because Earth is the only planet with biological agents, as far as we know, it is the only one that has all

  17. The Impact of Process Capability on Service Reliability for Critical Infrastructure Providers

    Science.gov (United States)

    Houston, Clemith J., Jr.

    2013-01-01

    This study investigated the relationship between organizational processes that have been identified as promoting resiliency and their impact on service reliability within the scope of critical infrastructure providers. The importance of critical infrastructure to the nation is evident from the body of research and is supported by instances where…

  18. Providing Survivable Real-Time Communication Service for Distributed Mission Critical Systems

    National Research Council Canada - National Science Library

    Zhao, Wei; Bettati, Riccardo; Vaidya, Nitin

    2005-01-01

    This document is the final report for Providing Survivable Real-Time Communication Service for Distributed Mission Critical Systems, a Texas A AND M project funded through the DARPA Fault Tolerant Networks Program...

  19. Cost Calculation Model for Logistics Service Providers

    Directory of Open Access Journals (Sweden)

    Zoltán Bokor

    2012-11-01

    Full Text Available The exact calculation of logistics costs has become a real challenge in logistics and supply chain management. It is essential to gain reliable and accurate costing information to attain efficient resource allocation within the logistics service provider companies. Traditional costing approaches, however, may not be sufficient to reach this aim in case of complex and heterogeneous logistics service structures. So this paper intends to explore the ways of improving the cost calculation regimes of logistics service providers and show how to adopt the multi-level full cost allocation technique in logistics practice. After determining the methodological framework, a sample cost calculation scheme is developed and tested by using estimated input data. Based on the theoretical findings and the experiences of the pilot project it can be concluded that the improved costing model contributes to making logistics costing more accurate and transparent. Moreover, the relations between costs and performances also become more visible, which enhances the effectiveness of logistics planning and controlling significantly

  20. Addressing Learning Style Criticism: The Unified Learning Style Model Revisited

    Science.gov (United States)

    Popescu, Elvira

    Learning style is one of the individual differences that play an important but controversial role in the learning process. This paper aims at providing a critical analysis regarding learning styles and their use in technology enhanced learning. The identified criticism issues are addressed by reappraising the so called Unified Learning Style Model (ULSM). A detailed description of the ULSM components is provided, together with their rationale. The practical applicability of the model in adaptive web-based educational systems and its advantages versus traditional learning style models are also outlined.

  1. Critically Important Object Security System Element Model

    Directory of Open Access Journals (Sweden)

    I. V. Khomyackov

    2012-03-01

    Full Text Available A stochastic model of critically important object security system element has been developed. The model includes mathematical description of the security system element properties and external influences. The state evolution of the security system element is described by the semi-Markov process with finite states number, the semi-Markov matrix and the initial semi-Markov process states probabilities distribution. External influences are set with the intensity of the Poisson thread.

  2. The high temperature Ising model is a critical percolation model

    NARCIS (Netherlands)

    Meester, R.W.J.; Camia, F.; Balint, A.

    2010-01-01

    We define a new percolation model by generalising the FK representation of the Ising model, and show that on the triangular lattice and at high temperatures, the critical point in the new model corresponds to the Ising model. Since the new model can be viewed as Bernoulli percolation on a random

  3. Critical Review of Membrane Bioreactor Models

    DEFF Research Database (Denmark)

    Naessens, W.; Maere, T.; Ratkovich, Nicolas Rios

    2012-01-01

    modelling. In this paper, the vast literature on hydrodynamic and integrated modelling in MBR is critically reviewed. Hydrodynamic models are used at different scales and focus mainly on fouling and only little on system design/optimisation. Integrated models also focus on fouling although the ones......Membrane bioreactor technology exists for a couple of decades, but has not yet overwhelmed the market due to some serious drawbacks of which operational cost due to fouling is the major contributor. Knowledge buildup and optimisation for such complex systems can heavily benefit from mathematical...

  4. On the criticality of inferred models

    International Nuclear Information System (INIS)

    Mastromatteo, Iacopo; Marsili, Matteo

    2011-01-01

    Advanced inference techniques allow one to reconstruct a pattern of interaction from high dimensional data sets, from probing simultaneously thousands of units of extended systems—such as cells, neural tissues and financial markets. We focus here on the statistical properties of inferred models and argue that inference procedures are likely to yield models which are close to singular values of parameters, akin to critical points in physics where phase transitions occur. These are points where the response of physical systems to external perturbations, as measured by the susceptibility, is very large and diverges in the limit of infinite size. We show that the reparameterization invariant metrics in the space of probability distributions of these models (the Fisher information) are directly related to the susceptibility of the inferred model. As a result, distinguishable models tend to accumulate close to critical points, where the susceptibility diverges in infinite systems. This region is the one where the estimate of inferred parameters is most stable. In order to illustrate these points, we discuss inference of interacting point processes with application to financial data and show that sensible choices of observation time scales naturally yield models which are close to criticality

  5. Critical analysis of algebraic collective models

    International Nuclear Information System (INIS)

    Moshinsky, M.

    1986-01-01

    The author shall understand by algebraic collective models all those based on specific Lie algebras, whether the latter are suggested through simple shell model considerations like in the case of the Interacting Boson Approximation (IBA), or have a detailed microscopic foundation like the symplectic model. To analyze these models critically, it is convenient to take a simple conceptual example of them in which all steps can be implemented analytically or through elementary numerical analysis. In this note he takes as an example the symplectic model in a two dimensional space i.e. based on a sp(4,R) Lie algebra, and show how through its complete discussion we can get a clearer understanding of the structure of algebraic collective models of nuclei. In particular he discusses the association of Hamiltonians, related to maximal subalgebras of our basic Lie algebra, with specific types of spectra, and the connections between spectra and shapes

  6. Critical care in the austere environment: providing exceptional care in unusual places.

    Science.gov (United States)

    Venticinque, Steven G; Grathwohl, Kurt W

    2008-07-01

    War and other disasters are inexorably linked to illness and injury. As a consequence of this, healthcare providers will be challenged to provide advanced physiological support to preserve human life. Given the mobility and modularity of modern medical systems, the ability to provide critical care outside of the confines of traditional hospitals under such circumstances has become not only a reality and periodic necessity, but an expectation. Austerity amplifies the complexity of providing high-level critical care, because resources are frequently limited, providers are asked to fill unexpected roles determined by necessity, security may be threatened, and the population at risk and their afflictions can be highly diverse. Our current deployed military medical experience and a review of published literature pertaining to civilian medical disaster response efforts support these stated challenges. The fundamentals of successful critical care practice in unusual settings include proper planning with an emphasis on attention to detail, the careful management of all resources, using the proper equipment, leveraging aeromedical evacuation assets, and employing the right people with the right skills. Adherence to sound, evidence-based, routine practice, within bounds of the circumstances, must underscore everything.

  7. Modelling critical NDVI curves in perennial ryegrass

    DEFF Research Database (Denmark)

    Gislum, R; Boelt, B

    2010-01-01

      The use of optical sensors to measure canopy reflectance and calculate crop index as e.g. normalized difference vegetation index (NDVI) is widely used in agricultural crops, but has so far not been implemented in herbage seed production. The present study has the purpose to develop a critical...... NDVI curve where the critical NDVI, defined as the minimum NDVI obtained to achieve a high seed yield, will be modelled during the growing season. NDVI measurements were made at different growing degree days (GDD) in a three year field experiment where different N application rates were applied....... There was a clear maximum in the correlation coefficient between seed yield and NDVI in the period from approximately 700 to 900 GDD. At this time there was an exponential relationship between NDVI and seed yield where highest seed yield were at NDVI ~0.9. Theoretically the farmers should aim for an NDVI of 0...

  8. The human factor: the critical importance of effective teamwork and communication in providing safe care.

    Science.gov (United States)

    Leonard, M; Graham, S; Bonacum, D

    2004-10-01

    Effective communication and teamwork is essential for the delivery of high quality, safe patient care. Communication failures are an extremely common cause of inadvertent patient harm. The complexity of medical care, coupled with the inherent limitations of human performance, make it critically important that clinicians have standardised communication tools, create an environment in which individuals can speak up and express concerns, and share common "critical language" to alert team members to unsafe situations. All too frequently, effective communication is situation or personality dependent. Other high reliability domains, such as commercial aviation, have shown that the adoption of standardised tools and behaviours is a very effective strategy in enhancing teamwork and reducing risk. We describe our ongoing patient safety implementation using this approach within Kaiser Permanente, a non-profit American healthcare system providing care for 8.3 million patients. We describe specific clinical experience in the application of surgical briefings, properties of high reliability perinatal care, the value of critical event training and simulation, and benefits of a standardised communication process in the care of patients transferred from hospitals to skilled nursing facilities. Additionally, lessons learned as to effective techniques in achieving cultural change, evidence of improving the quality of the work environment, practice transfer strategies, critical success factors, and the evolving methods of demonstrating the benefit of such work are described.

  9. Knowledge of Critical Care Provider on Prevention of Ventilator Associated Pneumonia

    Directory of Open Access Journals (Sweden)

    Passang Chiki Sherpa

    2014-01-01

    Full Text Available Background: Ventilator-associated pneumonia (VAP continues to be an important cause of morbidity and mortality in ventilated patient. Prevention of VAP in critically ill patient is significant concern for health care team in intensive care units (ICUs. Knowledge on prevention of VAP would have a significant impact on patient outcome. Aims and Objectives: To assess knowledge on prevention of VAP in critical care providers and to find the association between knowledge on prevention of VAP and educational qualification and years of experience in ICUs. Settings and Design: The study was conducted in 5 different ICUs of Kasturba Hospital, Manipal, and using descriptive study design. Material and Methods: The study involved a purposive sample of 138 critical care providers. Critical care providers who were willing to participate in the study were included. Tools on demographic proforma and self-administered structured knowledge questionnaire on prevention of VAP were developed and content validity was established. The reliability of the tools was established.The data was categorized and analyzed by using descriptive and inferential statistics. The SPSS 16.0 version was used for the analysis of the study. Result: Majority 89.1% of the participant were 20-29 years, 63% unmarried 51.4% had completed diploma course and majority 81.2% were from nursing discipline. The study revealed that only 55.80% of subjects were having adequate knowledge on prevention of VAP based on median score. There was no significant association between knowledge score and educational qualification (÷²=0, p=0.833, years of experience in ICU (÷²= 2.221, p=0.329.

  10. Critical Business Requirements Model and Metrics for Intranet ROI

    OpenAIRE

    Luqi; Jacoby, Grant A.

    2005-01-01

    Journal of Electronic Commerce Research, Vol. 6, No. 1, pp. 1-30. This research provides the first theoretical model, the Intranet Efficiency and Effectiveness Model (IEEM), to measure intranet overall value contributions based on a corporation’s critical business requirements by applying a balanced baseline of metrics and conversion ratios linked to key business processes of knowledge workers, IT managers and business decision makers -- in effect, closing the gap of understanding...

  11. Model of designating the critical damages

    Directory of Open Access Journals (Sweden)

    Zwolińska Bożena

    2017-06-01

    Full Text Available The article consists of two parts which make for an integral body. This article depicts the method of designating the critical damages in accordance with lean maintenance method. Author considered exemplary production system (serial-parallel in which in time Δt appeared a damage on three different objects. Article depicts the mathematical model which enables determination of an indicator called “prioritized digit of the device”. In the developed model there were considered some parameters: production abilities of devices, existence of potential vicarious devices, position of damage in the production stream based on the capacity of operational buffers, time needed to remove the damages and influence of damages to the finalization of customers’ orders – CEF indicator.

  12. Evaluating Models of Human Performance: Safety-Critical Systems Applications

    Science.gov (United States)

    Feary, Michael S.

    2012-01-01

    This presentation is part of panel discussion on Evaluating Models of Human Performance. The purpose of this panel is to discuss the increasing use of models in the world today and specifically focus on how to describe and evaluate models of human performance. My presentation will focus on discussions of generating distributions of performance, and the evaluation of different strategies for humans performing tasks with mixed initiative (Human-Automation) systems. I will also discuss issues with how to provide Human Performance modeling data to support decisions on acceptability and tradeoffs in the design of safety critical systems. I will conclude with challenges for the future.

  13. `Dhara': An Open Framework for Critical Zone Modeling

    Science.gov (United States)

    Le, P. V.; Kumar, P.

    2016-12-01

    Processes in the Critical Zone, which sustain terrestrial life, are tightly coupled across hydrological, physical, biological, chemical, pedological, geomorphological and ecological domains over both short and long timescales. Observations and quantification of the Earth's surface across these domains using emerging high resolution measurement technologies such as light detection and ranging (lidar) and hyperspectral remote sensing are enabling us to characterize fine scale landscape attributes over large spatial areas. This presents a unique opportunity to develop novel approaches to model the Critical Zone that can capture fine scale intricate dependencies across the different processes in 3D. The development of interdisciplinary tools that transcend individual disciplines and capture new levels of complexity and emergent properties is at the core of Critical Zone science. Here we introduce an open framework for high-performance computing model (`Dhara') for modeling complex processes in the Critical Zone. The framework is designed to be modular in structure with the aim to create uniform and efficient tools to facilitate and leverage process modeling. It also provides flexibility to maintain, collaborate, and co-develop additional components by the scientific community. We show the essential framework that simulates ecohydrologic dynamics, and surface - sub-surface coupling in 3D using hybrid parallel CPU-GPU. We demonstrate that the open framework in Dhara is feasible for detailed, multi-processes, and large-scale modeling of the Critical Zone, which opens up exciting possibilities. We will also present outcomes from a Modeling Summer Institute led by Intensively Managed Critical Zone Observatory (IMLCZO) with representation from several CZOs and international representatives.

  14. Model of designating the critical damages

    Directory of Open Access Journals (Sweden)

    Zwolińska Bożena

    2017-06-01

    Full Text Available Managing company in the lean way presumes no breakdowns nor reserves in the whole delivery chain. However, achieving such low indicators is impossible. That is why in some production plants it is extremely important to focus on preventive actions which can limit damages. This article depicts the method of designating the critical damages in accordance with lean maintenance method. The article consists of two parts which make for an integral body. Part one depicts the characteristic of a realistic object, it also contains productions capabilities analysis of certain areas within the production structure. Part two depicts the probabilistic model of shaping maximal time loss basing on emptying and filling interoperational buffers.

  15. Causal Measurement Models: Can Criticism Stimulate Clarification?

    Science.gov (United States)

    Markus, Keith A.

    2016-01-01

    In their 2016 work, Aguirre-Urreta et al. provided a contribution to the literature on causal measurement models that enhances clarity and stimulates further thinking. Aguirre-Urreta et al. presented a form of statistical identity involving mapping onto the portion of the parameter space involving the nomological net, relationships between the…

  16. Modeling Resource Hotspots: Critical Linkages and Processes

    Science.gov (United States)

    Daher, B.; Mohtar, R.; Pistikopoulos, E.; McCarl, B. A.; Yang, Y.

    2017-12-01

    Growing demands for interconnected resources emerge in the form of hotspots of varying characteristics. The business as usual allocation model cannot address the current, let alone anticipated, complex and highly interconnected resource challenges we face. A new paradigm for resource allocation must be adopted: one that identifies cross-sectoral synergies and, that moves away from silos to recognition of the nexus and integration of it. Doing so will result in new opportunities for business growth, economic development, and improved social well-being. Solutions and interventions must be multi-faceted; opportunities should be identified with holistic trade-offs in mind. No single solution fits all: different hotspots will require distinct interventions. Hotspots have varying resource constraints, stakeholders, goals and targets. The San Antonio region represents a complex resource hotspot with promising potential: its rapidly growing population, the Eagle Ford shale play, and the major agricultural activity there makes it a hotspot with many competing demands. Stakeholders need tools to allow them to knowledgeably address impending resource challenges. This study will identify contemporary WEF nexus questions and critical system interlinkages that will inform the modeling of the tightly interconnected resource systems and stresses using the San Antonio Region as a base; it will conceptualize a WEF nexus modeling framework, and develop assessment criteria to inform integrative planning and decision making.

  17. The "virtual" obstetrical intensive care unit: providing critical care for contemporary obstetrics in nontraditional locations.

    Science.gov (United States)

    Leovic, Michael P; Robbins, Hailey N; Foley, Michael R; Starikov, Roman S

    2016-12-01

    Management of the critically ill pregnant patient presents a clinical dilemma in which there are sparse objective data to determine the optimal setting for provision of high-quality care to these patients. This clinical scenario will continue to present a challenge for providers as the chronic illness and comorbid conditions continue to become more commonly encountered in the obstetric population. Various care models exist across a broad spectrum of facilities that are characterized by differing levels of resources; however, no studies have identified which model provides the highest level of care and patient safety while maintaining a reasonable degree of cost-effectiveness. The health care needs of the critically ill obstetric patient calls for clinicians to move beyond the traditional definition of the intensive care unit and develop a well-rounded, quickly responsive, and communicative interdisciplinary team that can provide high-quality, unique, and versatile care that best meets the needs of each particular patient. We propose a model in which a virtual intensive care unit team composed of preselected specialists from multiple disciplines (maternal-fetal medicine, neonatology, obstetric anesthesiology, cardiology, pulmonology, etc) participate in the provision of individualized, precontemplated care that is readily adapted to the specific patient's clinical needs, regardless of setting. With this team-based approach, an environment of trust and familiarity is fostered among team members and well thought-out patient care plans are developed through routine prebrief discussions regarding individual clinical care for parturients anticipated to required critical care services. Incorporating debriefings between team members following these intricate cases will allow for the continued evolution of care as the medical needs of this patient population change as well. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Introduced fire ants can exclude native ants from critical mutualist-provided resources.

    Science.gov (United States)

    Wilder, Shawn M; Barnum, Thomas R; Holway, David A; Suarez, Andrew V; Eubanks, Micky D

    2013-05-01

    Animals frequently experience resource imbalances in nature. For ants, one resource that may be particularly valuable for both introduced and native species is high-carbohydrate honeydew from hemipteran mutualists. We conducted field and laboratory experiments: (1) to test if red imported fire ants (Solenopsis invicta) competed with native ants for access to mutualisms with aphids, and (2) to quantify the effects of aphid honeydew presence or absence on colony growth of native ants. We focused on native dolichoderine ants (Formicidae, Dolichoderinae) because they are abundant ants that have omnivorous diets that frequently include mutualist-provided carbohydrates. At two sites in the southeastern US, native dolichoderine ants were far less frequent, and fire ants more frequent, at carbohydrate baits than would be expected based on their frequency in pitfall traps. A field experiment confirmed that a native ant species, Dorymyrmex bureni, was only found tending aphids when populations of S. invicta were suppressed. In the laboratory, colonies of native dolichoderine ants with access to both honeydew and insect prey had twice as many workers and over twice as much brood compared to colonies fed only ad libitum insect prey. Our results provide the first experimental evidence that introduced ants compete for access to mutualist-provided carbohydrates with native ants and that these carbohydrates represent critical resources for both introduced and native ants. These results challenge traditional paradigms of arthropod and ant nutrition and contribute to growing evidence of the importance of nutrition in mediating ecological interactions.

  19. Teaching for Art Criticism: Incorporating Feldman's Critical Analysis Learning Model in Students' Studio Practice

    Science.gov (United States)

    Subramaniam, Maithreyi; Hanafi, Jaffri; Putih, Abu Talib

    2016-01-01

    This study adopted 30 first year graphic design students' artwork, with critical analysis using Feldman's model of art criticism. Data were analyzed quantitatively; descriptive statistical techniques were employed. The scores were viewed in the form of mean score and frequencies to determine students' performances in their critical ability.…

  20. Modern statistical models for forensic fingerprint examinations: a critical review.

    Science.gov (United States)

    Abraham, Joshua; Champod, Christophe; Lennard, Chris; Roux, Claude

    2013-10-10

    Over the last decade, the development of statistical models in support of forensic fingerprint identification has been the subject of increasing research attention, spurned on recently by commentators who claim that the scientific basis for fingerprint identification has not been adequately demonstrated. Such models are increasingly seen as useful tools in support of the fingerprint identification process within or in addition to the ACE-V framework. This paper provides a critical review of recent statistical models from both a practical and theoretical perspective. This includes analysis of models of two different methodologies: Probability of Random Correspondence (PRC) models that focus on calculating probabilities of the occurrence of fingerprint configurations for a given population, and Likelihood Ratio (LR) models which use analysis of corresponding features of fingerprints to derive a likelihood value representing the evidential weighting for a potential source. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  1. Teaching For Art Criticism: Incorporating Feldman’s Critical Analysis Learning Model In Students’ Studio Practice

    OpenAIRE

    Maithreyi Subramaniam; Jaffri Hanafi; Abu Talib Putih

    2016-01-01

    This study adopted 30 first year graphic design students’ artwork, with critical analysis using Feldman’s model of art criticism. Data were analyzed quantitatively; descriptive statistical techniques were employed. The scores were viewed in the form of mean score and frequencies to determine students’ performances in their critical ability. Pearson Correlation Coefficient was used to find out the correlation between students’ studio practice and art critical ability scores. The...

  2. Statistical and RBF NN models : providing forecasts and risk assessment

    OpenAIRE

    Marček, Milan

    2009-01-01

    Forecast accuracy of economic and financial processes is a popular measure for quantifying the risk in decision making. In this paper, we develop forecasting models based on statistical (stochastic) methods, sometimes called hard computing, and on a soft method using granular computing. We consider the accuracy of forecasting models as a measure for risk evaluation. It is found that the risk estimation process based on soft methods is simplified and less critical to the question w...

  3. Examining influences on speaking up among critical care healthcare providers in the United Arab Emirates.

    Science.gov (United States)

    Edrees, Hanan H; Ismail, Mohd Nasir Mohd; Kelly, Bernadette; Goeschel, Christine A; Berenholtz, Sean M; Pronovost, Peter J; Al Obaidli, Ali Abdul Kareem; Weaver, Sallie J

    2017-11-01

    Assess perceived barriers to speaking up and to provide recommendations for reducing barriers to reporting adverse events and near misses. A six-item survey was administered to critical care providers in 19 Intensive Care Units in Abu Dhabi as part of an organizational safety and quality improvement effort. Questions elicited perspectives about influences on reporting, perceived barriers and recommendations for conveying patient safety as an organizational priority. Qualitative thematic analyses were conducted for open-ended questions. A total of 1171 participants were invited to complete the survey and 639 responded (response rate = 54.6%). Compared to other stakeholders (e.g. the media, public), a larger proportion of respondents 'agreed/strongly agreed' that corporate health system leadership and the health regulatory authority encouraged and supported error reporting (83%; 75%), and had the most influence on their decisions to report (81%; 74%). 29.5% of respondents cited fear of repercussion as a barrier, and 21.3% of respondents indicated no barriers to reporting. Barriers included perceptions of a culture of blame and issues with reporting procedures. Recommendations to establish patient safety as an organizational priority included creating supportive environments to discuss errors, hiring staff to advocate for patient safety, and implementing policies to standardize clinical practices and streamline reporting procedures. Influences on reporting perceived by providers in the UAE were similar to those in the US and other countries. These findings highlight the roles of corporate leadership and regulators in developing non-punitive environments where reporting is a valuable and safe activity. © The Author 2017. Published by Oxford University Press in association with the International Society for Quality in Health Care. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  4. A Model for Teaching Critical Thinking

    Science.gov (United States)

    Emerson, Marnice K.

    2013-01-01

    In an age in which information is available almost instantly and in quantities unimagined just a few decades ago, most educators would agree that teaching adult learners to think critically about what they are reading, seeing, and hearing has never been more important. But just what is critical thinking? Do adult learners agree with educators that…

  5. Critical thinking in clinical nurse education: application of Paul's model of critical thinking.

    Science.gov (United States)

    Andrea Sullivan, E

    2012-11-01

    Nurse educators recognize that many nursing students have difficulty in making decisions in clinical practice. The ability to make effective, informed decisions in clinical practice requires that nursing students know and apply the processes of critical thinking. Critical thinking is a skill that develops over time and requires the conscious application of this process. There are a number of models in the nursing literature to assist students in the critical thinking process; however, these models tend to focus solely on decision making in hospital settings and are often complex to actualize. In this paper, Paul's Model of Critical Thinking is examined for its application to nursing education. I will demonstrate how the model can be used by clinical nurse educators to assist students to develop critical thinking skills in all health care settings in a way that makes critical thinking skills accessible to students. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Toward Developing Genetic Algorithms to Aid in Critical Infrastructure Modeling

    Energy Technology Data Exchange (ETDEWEB)

    2007-05-01

    Today’s society relies upon an array of complex national and international infrastructure networks such as transportation, telecommunication, financial and energy. Understanding these interdependencies is necessary in order to protect our critical infrastructure. The Critical Infrastructure Modeling System, CIMS©, examines the interrelationships between infrastructure networks. CIMS© development is sponsored by the National Security Division at the Idaho National Laboratory (INL) in its ongoing mission for providing critical infrastructure protection and preparedness. A genetic algorithm (GA) is an optimization technique based on Darwin’s theory of evolution. A GA can be coupled with CIMS© to search for optimum ways to protect infrastructure assets. This includes identifying optimum assets to enforce or protect, testing the addition of or change to infrastructure before implementation, or finding the optimum response to an emergency for response planning. This paper describes the addition of a GA to infrastructure modeling for infrastructure planning. It first introduces the CIMS© infrastructure modeling software used as the modeling engine to support the GA. Next, the GA techniques and parameters are defined. Then a test scenario illustrates the integration with CIMS© and the preliminary results.

  7. A note on the criticisms against the internationalization process model

    OpenAIRE

    Hadjikhani, Amjad

    1997-01-01

    The internationalization process model introduced three decades ago still influences international business studies. Since that time, a growing number of researchers have tested the model to show its strengths and weaknesses. Among the critics, some focus on the weakness of the theoretical aspects, while others argue against parts of the model. This paper will review these criticisms and compare them with the original ideas in the internationalization model. One criticized aspect of the inter...

  8. Critical properties of the Kitaev-Heisenberg Model

    Science.gov (United States)

    Sizyuk, Yuriy; Price, Craig; Perkins, Natalia

    2013-03-01

    Collective behavior of local moments in Mott insulators in the presence of strong spin-orbit coupling is one of the most interesting questions in modern condensed matter physics. Here we study the finite temperature properties of the Kitaev-Heisenberg model which describe the interactions between the pseudospin J = 1 / 2 iridium moments on the honeycomb lattice. This model was suggested as a possible model to explain low-energy physics of AIr2O3 compounds. In our study we show that the Kitaev-Heisenberg model may be mapped into the six state clock model with an intermediate power-law phase at finite temperatures. In the framework of the Ginsburg-Landau theory, we provide an analysis of the critical properties of the finite-temperature ordering transitions. NSF grant DMR-1005932

  9. Evaluation of District-Provided Professional Development on Critical Thinking Skills

    Science.gov (United States)

    Bedosky, Michael J.

    2013-01-01

    Critical thinking skills are often not being taught or used in classrooms. Instead, more testing has become the norm, leaving students less equipped to discern information and become well-informed, conscientious citizens. Based on research concerning the importance of critical thinking skills and professional development for teachers, this study…

  10. Comprehensive Care For Joint Replacement Model - Provider Data

    Data.gov (United States)

    U.S. Department of Health & Human Services — Comprehensive Care for Joint Replacement Model - provider data. This data set includes provider data for two quality measures tracked during an episode of care:...

  11. A Review of Accident Modelling Approaches for Complex Critical Sociotechnical Systems

    National Research Council Canada - National Science Library

    Qureshi, Zahid H

    2008-01-01

    .... This report provides a review of key traditional accident modelling approaches and their limitations, and describes new system-theoretic approaches to the modelling and analysis of accidents in safety-critical systems...

  12. Moral distress among Ugandan nurses providing HIV care: a critical ethnography.

    Science.gov (United States)

    Harrowing, Jean N; Mill, Judy

    2010-06-01

    The phenomenon of moral distress among nurses has been described in a variety of high-income countries and practice settings. Defined as the biopsychosocial, cognitive, and behavioural effects experienced by clinicians when their values are compromised by internal or external constraints, it results from the inability to provide the desired care to patients. No research has been reported that addresses moral distress in severely resource-challenged regions such as sub-Saharan Africa. To describe the manifestation and impact of moral distress as it was experienced by Ugandan nurses who provided care to HIV-infected or -affected people. A critical ethnography was conducted with 24 acute care and public health nurses at a large referral centre in Uganda. Data were collected through interviews, observation, and focus group discussions. Participants described their passion for nursing and commitment to patients. They experienced moral distress when a lack of resources put patients' wellbeing at risk. The trauma imposed by systemic challenges on the nursing profession was acknowledged, as was the perception that the public blamed nurses for poor patient outcomes. However, participants were determined to serve to the best of their abilities and to take satisfaction from any contributions they were able to make. They cited the importance of education in the development of their capacity to provide care with a positive attitude, and demonstrated a collective resilience as they discussed strategies for addressing issues that affected them and their colleagues. The experience of moral distress among nurses in Uganda differed somewhat from the experience of nurses in high-income countries. Constraints imposed by the inability to implement skills and knowledge to their fullest extent, as well as a lack of resources and infrastructure may result in the omission of care for patients. Moral distress appears to manifest within a relational and contextual environment and

  13. Assessment of Stirling Technology Has Provided Critical Data Leading Toward Flight Readiness of the Stirling Converter

    Science.gov (United States)

    Thieme, Lanny G.

    2001-01-01

    The NASA Glenn Research Center is supporting the development of a Stirling converter with the Department of Energy (DOE, Germantown, Maryland) for an advanced Stirling Radioisotope Power System (SRPS) to provide spacecraft onboard electric power for NASA space science missions. A key technology assessment completed by Glenn and DOE has led to the SRPS being identified as a high-efficiency power source for such deep space missions as the Europa Orbiter and the Solar Probe. In addition, the Stirling system is now being considered for unmanned Mars rovers, especially where mission profiles may exclude the use of photovoltaic power systems, such as exploration at high Martian latitudes or for missions of long duration. The SRPS efficiency of over 20 percent will reduce the required amount of radioisotope by more than a factor of 3 in comparison to current radioisotope thermoelectric generators. This significantly reduces radioisotope cost, radiological inventory, and system cost, and it provides efficient use of scarce radioisotope resources. In support of this technology assessment, Glenn conducted a series of independent evaluations and tests to determine the technology readiness of a 55-We Stirling converter developed by Stirling Technology Company (Kennewick, Washington) and DOE. Key areas evaluated by Glenn included: 1) Radiation tolerance of materials; 2) Random vibration testing of the Stirling converter in Glenn's Structural Dynamics Lab to simulate operation in the launch environment; 3) Electromagnetic interference and compatibility (EMI/EMC) of the converter operating in Glenn's EMI lab; Independent failure modes, effects, and criticality analysis, and life and reliability 4. Independent failure modes, effects, and criticality analysis, and life and reliability assessment; and 5) SRPS cost estimate. The data from these evaluations were presented to NASA Headquarters and the Jet Propulsion Laboratory mission office by a joint industry/Government team

  14. The human factor: the critical importance of effective teamwork and communication in providing safe care

    OpenAIRE

    Leonard, M; Graham, S; Bonacum, D

    2004-01-01

    Effective communication and teamwork is essential for the delivery of high quality, safe patient care. Communication failures are an extremely common cause of inadvertent patient harm. The complexity of medical care, coupled with the inherent limitations of human performance, make it critically important that clinicians have standardised communication tools, create an environment in which individuals can speak up and express concerns, and share common "critical language" to alert team members...

  15. Customer-Provider Strategic Alignment: A Maturity Model

    Science.gov (United States)

    Luftman, Jerry; Brown, Carol V.; Balaji, S.

    This chapter presents a new model for assessing the maturity of a ­customer-provider relationship from a collaborative service delivery perspective: the Customer-Provider Strategic Alignment Maturity (CPSAM) Model. This model builds on recent research for effectively managing the customer-provider relationship in IT service outsourcing contexts and a validated model for assessing alignment across internal IT service units and their business customers within the same organization. After reviewing relevant literature by service science and information systems researchers, the six overarching components of the maturity model are presented: value measurements, governance, partnership, communications, human resources and skills, and scope and architecture. A key assumption of the model is that all of the components need be addressed to assess and improve customer-provider alignment. Examples of specific metrics for measuring the maturity level of each component over the five levels of maturity are also presented.

  16. Teaching For Art Criticism: Incorporating Feldman’s Critical Analysis Learning Model In Students’ Studio Practice

    Directory of Open Access Journals (Sweden)

    Maithreyi Subramaniam

    2016-01-01

    Full Text Available This study adopted 30 first year graphic design students’ artwork, with critical analysis using Feldman’s model of art criticism. Data were analyzed quantitatively; descriptive statistical techniques were employed. The scores were viewed in the form of mean score and frequencies to determine students’ performances in their critical ability. Pearson Correlation Coefficient was used to find out the correlation between students’ studio practice and art critical ability scores. The findings showed most students performed slightly better than average in the critical analyses and performed best in selecting analysis among the four dimensions assessed. In the context of the students’ studio practice and critical ability, findings showed there are some connections between the students’ art critical ability and studio practice.

  17. A risk assessment model for selecting cloud service providers

    OpenAIRE

    Cayirci, Erdal; Garaga, Alexandr; Santana de Oliveira, Anderson; Roudier, Yves

    2016-01-01

    The Cloud Adoption Risk Assessment Model is designed to help cloud customers in assessing the risks that they face by selecting a specific cloud service provider. It evaluates background information obtained from cloud customers and cloud service providers to analyze various risk scenarios. This facilitates decision making an selecting the cloud service provider with the most preferable risk profile based on aggregated risks to security, privacy, and service delivery. Based on this model we ...

  18. A quenched c = 1 critical matrix model

    International Nuclear Information System (INIS)

    Qiu, Zongan; Rey, Soo-Jong.

    1990-12-01

    We study a variant of the Penner-Distler-Vafa model, proposed as a c = 1 quantum gravity: 'quenched' matrix model with logarithmic potential. The model is exactly soluble, and exhibits a two-cut branching as observed in multicritical unitary matrix models and multicut Hermitian matrix models. Using analytic continuation of the power in the conventional polynomial potential, we also show that both the Penner-Distler-Vafa model and our 'quenched' matrix model satisfy Virasoro algebra constraints

  19. IEEE 802.15.4 Frame Aggregation Enhancement to Provide High Performance in Life-Critical Patient Monitoring Systems.

    Science.gov (United States)

    Akbar, Muhammad Sajjad; Yu, Hongnian; Cang, Shuang

    2017-01-28

    In wireless body area sensor networks (WBASNs), Quality of Service (QoS) provision for patient monitoring systems in terms of time-critical deadlines, high throughput and energy efficiency is a challenging task. The periodic data from these systems generates a large number of small packets in a short time period which needs an efficient channel access mechanism. The IEEE 802.15.4 standard is recommended for low power devices and widely used for many wireless sensor networks applications. It provides a hybrid channel access mechanism at the Media Access Control (MAC) layer which plays a key role in overall successful transmission in WBASNs. There are many WBASN's MAC protocols that use this hybrid channel access mechanism in variety of sensor applications. However, these protocols are less efficient for patient monitoring systems where life critical data requires limited delay, high throughput and energy efficient communication simultaneously. To address these issues, this paper proposes a frame aggregation scheme by using the aggregated-MAC protocol data unit (A-MPDU) which works with the IEEE 802.15.4 MAC layer. To implement the scheme accurately, we develop a traffic patterns analysis mechanism to understand the requirements of the sensor nodes in patient monitoring systems, then model the channel access to find the performance gap on the basis of obtained requirements, finally propose the design based on the needs of patient monitoring systems. The mechanism is initially verified using numerical modelling and then simulation is conducted using NS2.29, Castalia 3.2 and OMNeT++. The proposed scheme provides the optimal performance considering the required QoS.

  20. Review on modeling and simulation of interdependent critical infrastructure systems

    International Nuclear Information System (INIS)

    Ouyang, Min

    2014-01-01

    Modern societies are becoming increasingly dependent on critical infrastructure systems (CISs) to provide essential services that support economic prosperity, governance, and quality of life. These systems are not alone but interdependent at multiple levels to enhance their overall performance. However, recent worldwide events such as the 9/11 terrorist attack, Gulf Coast hurricanes, the Chile and Japanese earthquakes, and even heat waves have highlighted that interdependencies among CISs increase the potential for cascading failures and amplify the impact of both large and small scale initial failures into events of catastrophic proportions. To better understand CISs to support planning, maintenance and emergency decision making, modeling and simulation of interdependencies across CISs has recently become a key field of study. This paper reviews the studies in the field and broadly groups the existing modeling and simulation approaches into six types: empirical approaches, agent based approaches, system dynamics based approaches, economic theory based approaches, network based approaches, and others. Different studies for each type of the approaches are categorized and reviewed in terms of fundamental principles, such as research focus, modeling rationale, and the analysis method, while different types of approaches are further compared according to several criteria, such as the notion of resilience. Finally, this paper offers future research directions and identifies critical challenges in the field. - Highlights: • Modeling approaches on interdependent critical infrastructure systems are reviewed. • I mainly review empirical, agent-based, system-dynamics, economic, network approaches. • Studies by each approach are sorted out in terms of fundamental principles. • Different approaches are further compared with resilience as the main criterion

  1. Critical review of glass performance modeling

    International Nuclear Information System (INIS)

    Bourcier, W.L.

    1994-07-01

    Borosilicate glass is to be used for permanent disposal of high-level nuclear waste in a geologic repository. Mechanistic chemical models are used to predict the rate at which radionuclides will be released from the glass under repository conditions. The most successful and useful of these models link reaction path geochemical modeling programs with a glass dissolution rate law that is consistent with transition state theory. These models have been used to simulate several types of short-term laboratory tests of glass dissolution and to predict the long-term performance of the glass in a repository. Although mechanistically based, the current models are limited by a lack of unambiguous experimental support for some of their assumptions. The most severe problem of this type is the lack of an existing validated mechanism that controls long-term glass dissolution rates. Current models can be improved by performing carefully designed experiments and using the experimental results to validate the rate-controlling mechanisms implicit in the models. These models should be supported with long-term experiments to be used for model validation. The mechanistic basis of the models should be explored by using modern molecular simulations such as molecular orbital and molecular dynamics to investigate both the glass structure and its dissolution process

  2. Critical review of glass performance modeling

    Energy Technology Data Exchange (ETDEWEB)

    Bourcier, W.L. [Lawrence Livermore National Lab., CA (United States)

    1994-07-01

    Borosilicate glass is to be used for permanent disposal of high-level nuclear waste in a geologic repository. Mechanistic chemical models are used to predict the rate at which radionuclides will be released from the glass under repository conditions. The most successful and useful of these models link reaction path geochemical modeling programs with a glass dissolution rate law that is consistent with transition state theory. These models have been used to simulate several types of short-term laboratory tests of glass dissolution and to predict the long-term performance of the glass in a repository. Although mechanistically based, the current models are limited by a lack of unambiguous experimental support for some of their assumptions. The most severe problem of this type is the lack of an existing validated mechanism that controls long-term glass dissolution rates. Current models can be improved by performing carefully designed experiments and using the experimental results to validate the rate-controlling mechanisms implicit in the models. These models should be supported with long-term experiments to be used for model validation. The mechanistic basis of the models should be explored by using modern molecular simulations such as molecular orbital and molecular dynamics to investigate both the glass structure and its dissolution process.

  3. Geobiology of the Critical Zone: the Hierarchies of Process, Form and Life provide an Integrated Ontology

    Science.gov (United States)

    Cotterill, Fenton P. D.

    2016-04-01

    Press). Equally, Africa's freshwater fish fauna stands apart in its high endemism, preponderance of highly specialized species flocks, and ancient lineages that have seeded recent radiations (Otero O 2010. Cybium 2010, 34(1): 93-113). Nevertheless, Africa's fossil record - botanical and zoological - is too patchy and incomplete to build palaeoenvironmental narratives with the precision needed to resolve details of mesoscale events in landscape dynamics (especially at timescales >10 000 yr). Ideally, the biological evidence we seek to resolve a high fidelity narrative of landscape dynamics must extend back into the Cenozoic, and quantify turnovers of individual species on respective landforms. Births, deaths and tenures of species are its core currencies. The genomic record holds this evidence in its evolutionary archives, and we can read these signatures in the DNA of living organisms. This interdisciplinary approach exploits patterns of DNA variation in living organisms to reconstruct evolutionary events in landscape history at the mesoscale. Coupling the technological advances in 21st century molecular biology (especially genomics) with key tenets of ecological theory, we can exploit the remarkable variety of evolutionary signals preserved in the extant biodiversity of a landscape. Deciphering the genomic record, Geoecodynamics exploits the fidelity of individual species to their respective habitats; where the biota has persisted within/on encompassing landforms. This spatial resolution is determined principally by the degree of niche conservatism that has acted to lock the species into finite ecophysiological boundaries in the landscape. These ecophysiological envelopes of species can be mapped and modelled in a GIS framework, using variables familiar to geomorphologists: including altitude, surface roughness, lithology, and especially drainage attributes (stream topology and limnological variables). Geoecodynamics studies terrestrial and aquatic species as

  4. Curing critical links in oscillator networks as power flow models

    International Nuclear Information System (INIS)

    Rohden, Martin; Meyer-Ortmanns, Hildegard; Witthaut, Dirk; Timme, Marc

    2017-01-01

    Modern societies crucially depend on the robust supply with electric energy so that blackouts of power grids can have far reaching consequences. Typically, large scale blackouts take place after a cascade of failures: the failure of a single infrastructure component, such as a critical transmission line, results in several subsequent failures that spread across large parts of the network. Improving the robustness of a network to prevent such secondary failures is thus key for assuring a reliable power supply. In this article we analyze the nonlocal rerouting of power flows after transmission line failures for a simplified AC power grid model and compare different strategies to improve network robustness. We identify critical links in the grid and compute alternative pathways to quantify the grid’s redundant capacity and to find bottlenecks along the pathways. Different strategies are developed and tested to increase transmission capacities to restore stability with respect to transmission line failures. We show that local and nonlocal strategies typically perform alike: one can equally well cure critical links by providing backup capacities locally or by extending the capacities of bottleneck links at remote locations. (paper)

  5. Model for the resistive critical current transition in composite superconductors

    International Nuclear Information System (INIS)

    Warnes, W.H.

    1988-01-01

    Much of the research investigating technological type-II superconducting composites relies on the measurement of the resistive critical current transition. We have developed a model for the resistive transition which improves on older models by allowing for the very different nature of monofilamentary and multifilamentary composite structures. The monofilamentary model allows for axial current flow around critical current weak links in the superconducting filament. The multifilamentary model incorporates an additional radial current transfer between neighboring filaments. The development of both models is presented. It is shown that the models are useful for extracting more information from the experimental data than was formerly possible. Specific information obtainable from the experimental voltage-current characteristic includes the distribution of critical currents in the composite, the average critical current of the distribution, the range of critical currents in the composite, the field and temperature dependence of the distribution, and the fraction of the composite dissipating energy in flux flow at any current. This additional information about the distribution of critical currents may be helpful in leading toward a better understanding of flux pinning in technological superconductors. Comparison of the models with several experiments is given and shown to be in reasonable agreement. Implications of the models for the measurement of critical currents in technological composites is presented and discussed with reference to basic flux pinning studies in such composites

  6. A Model for Critical Games Literacy

    Science.gov (United States)

    Apperley, Tom; Beavis, Catherine

    2013-01-01

    This article outlines a model for teaching both computer games and videogames in the classroom for teachers. The model illustrates the connections between in-game actions and youth gaming culture. The article explains how the out-of-school knowledge building, creation and collaboration that occurs in gaming and gaming culture has an impact on…

  7. Bring Your Own Device - Providing Reliable Model of Data Access

    Directory of Open Access Journals (Sweden)

    Stąpór Paweł

    2016-10-01

    Full Text Available The article presents a model of Bring Your Own Device (BYOD as a model network, which provides the user reliable access to network resources. BYOD is a model dynamically developing, which can be applied in many areas. Research network has been launched in order to carry out the test, in which as a service of BYOD model Work Folders service was used. This service allows the user to synchronize files between the device and the server. An access to the network is completed through the wireless communication by the 802.11n standard. Obtained results are shown and analyzed in this article.

  8. Critical manifold of the kagome-lattice Potts model

    Science.gov (United States)

    Lykke Jacobsen, Jesper; Scullard, Christian R.

    2012-12-01

    Any two-dimensional infinite regular lattice G can be produced by tiling the plane with a finite subgraph B⊆G we call B a basis of G. We introduce a two-parameter graph polynomial PB(q, v) that depends on B and its embedding in G. The algebraic curve PB(q, v) = 0 is shown to provide an approximation to the critical manifold of the q-state Potts model, with coupling v = eK - 1, defined on G. This curve predicts the phase diagram not only in the physical ferromagnetic regime (v > 0), but also in the antiferromagnetic (v computation of PB(q, v) can be used to detect exact solvability of the Potts model on G. We illustrate the method for two choices of G: the square lattice, where the Potts model has been exactly solved, and the kagome lattice, where it has not. For the square lattice we correctly reproduce the known phase diagram, including the antiferromagnetic transition and the singularities in the Berker-Kadanoff phase at certain Beraha numbers. For the kagome lattice, taking the smallest basis with six edges we recover a well-known (but now refuted) conjecture of F Y Wu. Larger bases provide successive improvements on this formula, giving a natural extension of Wu’s approach. We perform large-scale numerical computations for comparison and find excellent agreement with the polynomial predictions. For v > 0 the accuracy of the predicted critical coupling vc is of the order 10-4 or 10-5 for the six-edge basis, and improves to 10-6 or 10-7 for the largest basis studied (with 36 edges). This article is part of ‘Lattice models and integrability’, a special issue of Journal of Physics A: Mathematical and Theoretical in honour of F Y Wu's 80th birthday.

  9. Critical appraisal and data extraction for systematic reviews of prediction modelling studies: the CHARMS checklist.

    Directory of Open Access Journals (Sweden)

    Karel G M Moons

    2014-10-01

    Full Text Available Carl Moons and colleagues provide a checklist and background explanation for critically appraising and extracting data from systematic reviews of prognostic and diagnostic prediction modelling studies. Please see later in the article for the Editors' Summary.

  10. Software reliability models for critical applications

    Energy Technology Data Exchange (ETDEWEB)

    Pham, H.; Pham, M.

    1991-12-01

    This report presents the results of the first phase of the ongoing EG&G Idaho, Inc. Software Reliability Research Program. The program is studying the existing software reliability models and proposes a state-of-the-art software reliability model that is relevant to the nuclear reactor control environment. This report consists of three parts: (1) summaries of the literature review of existing software reliability and fault tolerant software reliability models and their related issues, (2) proposed technique for software reliability enhancement, and (3) general discussion and future research. The development of this proposed state-of-the-art software reliability model will be performed in the second place. 407 refs., 4 figs., 2 tabs.

  11. Software reliability models for critical applications

    Energy Technology Data Exchange (ETDEWEB)

    Pham, H.; Pham, M.

    1991-12-01

    This report presents the results of the first phase of the ongoing EG G Idaho, Inc. Software Reliability Research Program. The program is studying the existing software reliability models and proposes a state-of-the-art software reliability model that is relevant to the nuclear reactor control environment. This report consists of three parts: (1) summaries of the literature review of existing software reliability and fault tolerant software reliability models and their related issues, (2) proposed technique for software reliability enhancement, and (3) general discussion and future research. The development of this proposed state-of-the-art software reliability model will be performed in the second place. 407 refs., 4 figs., 2 tabs.

  12. Relevance of information warfare models to critical infrastructure ...

    African Journals Online (AJOL)

    This article illustrates the relevance of information warfare models to critical infrastructure protection. Analogies of information warfare models to those of information security and information systems were used to deconstruct the models into their fundamental components and this will be discussed. The models were applied ...

  13. Promoting gynecologic cancer awareness at a critical juncture--where women and providers meet.

    Science.gov (United States)

    Cooper, Crystale Purvis; Gelb, Cynthia A; Rodriguez, Juan; Hawkins, Nikki A

    2014-06-01

    Given the absence of effective population-based screening tests for ovarian, uterine, vaginal, and vulvar cancers, early detection can depend on women and health care providers recognizing the potential significance of symptoms. In 2008, the Centers for Disease Control and Prevention's (CDC) Inside Knowledge campaign began distributing consumer education materials promoting awareness of gynecologic cancer symptoms. We investigated providers' in-office use of CDC gynecologic cancer materials and their recognition of the symptoms highlighted in the materials. We analyzed data from a national 2012 survey of US primary care physicians, nurse practitioners, and gynecologists (N = 1,380). Less than a quarter of providers (19.4%) reported using CDC gynecologic cancer education materials in their offices. The provider characteristics associated with the use of CDC materials were not consistent across specialties. However, recognition of symptoms associated with gynecologic cancers was consistently higher among providers who reported using CDC materials. The possibility that providers were educated about gynecologic cancer symptoms through the dissemination of materials intended for their patients is intriguing and warrants further investigation. Distributing consumer education materials in health care provider offices remains a priority for the Inside Knowledge campaign, as the setting where women and health care providers interact is one of the most crucial venues to promote awareness of gynecologic cancer symptoms.

  14. CRITICAL ANALYSIS OF EVALUATION MODEL LOMCE

    Directory of Open Access Journals (Sweden)

    José Luis Bernal Agudo

    2015-06-01

    Full Text Available The evaluation model that the LOMCE projects sinks its roots into the neoliberal beliefs, reflecting a specific way of understanding the world. What matters is not the process but the results, being the evaluation the center of the education-learning processes. It presents an evil planning, since the theory that justifies the model doesn’t specify upon coherent proposals, where there is an excessive worry for excellence and diversity is left out. A comprehensive way of understanding education should be recovered.

  15. Promoting Gynecologic Cancer Awareness at a Critical Juncture—Where Women and Providers Meet

    Science.gov (United States)

    Cooper, Crystale Purvis; Rodriguez, Juan; Hawkins, Nikki A

    2015-01-01

    Given the absence of effective population-based screening tests for ovarian, uterine, vaginal, and vulvar cancers, early detection can depend on women and health care providers recognizing the potential significance of symptoms. In 2008, the Centers for Disease Control and Prevention’s (CDC) Inside Knowledge campaign began distributing consumer education materials promoting awareness of gynecologic cancer symptoms. We investigated providers’ in-office use of CDC gynecologic cancer materials and their recognition of the symptoms highlighted in the materials. We analyzed data from a national 2012 survey of US primary care physicians, nurse practitioners, and gynecologists (N = 1,380). Less than a quarter of providers (19.4 %) reported using CDC gynecologic cancer education materials in their offices. The provider characteristics associated with the use of CDC materials were not consistent across specialties. However, recognition of symptoms associated with gynecologic cancers was consistently higher among providers who reported using CDC materials. The possibility that providers were educated about gynecologic cancer symptoms through the dissemination of materials intended for their patients is intriguing and warrants further investigation. Distributing consumer education materials in health care provider offices remains a priority for the Inside Knowledge campaign, as the setting where women and health care providers interact is one of the most crucial venues to promote awareness of gynecologic cancer symptoms. PMID:24214840

  16. Uncertainty modelling of critical column buckling for reinforced ...

    Indian Academy of Sciences (India)

    Buckling is a critical issue for structural stability in structural design. ... This study investigates the material uncertainties on column design and proposes an uncertainty model for critical column buckling reinforced concrete buildings. ... Civil Engineering Department, Suleyman Demirel University, Isparta 32260, Turkey ...

  17. A Conceptual Model for Teaching Critical Thinking in a Knowledge Economy

    Science.gov (United States)

    Chadwick, Clifton

    2011-01-01

    Critical thinking, viewed as rational and analytic thinking, is crucial for participation in a knowledge economy and society. This article provides a brief presentation of the importance of teaching critical thinking in a knowledge economy; suggests a conceptual model for teaching thinking; examines research on the historical role of teachers in…

  18. Levels of Interaction Provided by Online Distance Education Models

    Science.gov (United States)

    Alhih, Mohammed; Ossiannilsson, Ebba; Berigel, Muhammet

    2017-01-01

    Interaction plays a significant role to foster usability and quality in online education. It is one of the quality standard to reveal the evidence of practice in online distance education models. This research study aims to evaluate levels of interaction in the practices of distance education centres. It is aimed to provide online distance…

  19. Ethical and Practical Considerations in Providing Critical Care to Patients With Ebola Virus Disease

    Science.gov (United States)

    Davey, Richard T.; Suffredini, Anthony F.; Chertow, Daniel S.

    2015-01-01

    Infectious disease epidemics in the past have given rise to psychologic and emotional responses among health-care workers (HCWs), stemming from fear of infection during patient care. Early experiences in the AIDS epidemic provide an example where fear of contagion resulted in differential treatment of patients infected with HIV. However, with a deeper understanding of AIDS pathogenesis and treatment, fear and discrimination diminished. Parallels exist between early experiences with AIDS and the present outbreak of Ebola virus disease in West Africa, particularly regarding discussions of medical futility in seriously ill patients. We provide a historical perspective on HCWs’ risk of infection during the provision of CPR, discuss physicians’ duty to treat in the face of perceived or actual HCW risk, and, finally, present the protocols implemented at the National Institutes of Health to reduce HCW risk while providing lifesaving and life-sustaining care. PMID:25764372

  20. Critical fluctuations in cortical models near instability

    Directory of Open Access Journals (Sweden)

    Matthew J. Aburn

    2012-08-01

    Full Text Available Computational studies often proceed from the premise that cortical dynamics operate in a linearly stable domain, where fluctuations dissipate quickly and show only short memory. Studies of human EEG, however, have shown significant autocorrelation at time lags on the scale of minutes, indicating the need to consider regimes where nonlinearities influence the dynamics. Statistical properties such as increased autocorrelation length, increased variance, power-law scaling and bistable switching have been suggested as generic indicators of the approach to bifurcation in nonlinear dynamical systems. We study temporal fluctuations in a widely-employed computational model (the Jansen-Rit model of cortical activity, examining the statistical signatures that accompany bifurcations. Approaching supercritical Hopf bifurcations through tuning of the background excitatory input, we find a dramatic increase in the autocorrelation length that depends sensitively on the direction in phase space of the input fluctuations and hence on which neuronal subpopulation is stochastically perturbed. Similar dependence on the input direction is found in the distribution of fluctuation size and duration, which show power law scaling that extends over four orders of magnitude at the Hopf bifurcation. We conjecture that the alignment in phase space between the input noise vector and the center manifold of the Hopf bifurcation is directly linked to these changes. These results are consistent with the possibility of statistical indicators of linear instability being detectable in real EEG time series. However, even in a simple cortical model, we find that these indicators may not necessarily be visible even when bifurcations are present because their expression can depend sensitively on the neuronal pathway of incoming fluctuations.

  1. Federated Modelling and Simulation for Critical Infrastructure Protection

    NARCIS (Netherlands)

    Rome, E.; Langeslag, P.J.H.; Usov, A.

    2014-01-01

    Modelling and simulation is an important tool for Critical Infrastructure (CI) dependency analysis, for testing methods for risk reduction, and as well for the evaluation of past failures. Moreover, interaction of such simulations with external threat models, e.g., a river flood model, or economic

  2. Uncertainty modelling of critical column buckling for reinforced ...

    Indian Academy of Sciences (India)

    gates the material uncertainties on column design and proposes an uncertainty model for critical ... ances the accuracy of the structural models by using experimental results and design codes. (Baalbaki et al ..... Elishakoff I 1999 Whys and hows in uncertainty modeling, probability, fuzziness and anti-optimization. New York: ...

  3. Critical Comments on the General Model of Instructional Communication

    Science.gov (United States)

    Walton, Justin D.

    2014-01-01

    This essay presents a critical commentary on McCroskey et al.'s (2004) general model of instructional communication. In particular, five points are examined which make explicit and problematize the meta-theoretical assumptions of the model. Comments call attention to the limitations of the model and argue for a broader approach to…

  4. The trajectory of experience of critical care nurses in providing end-of-life care: A qualitative descriptive study.

    Science.gov (United States)

    Ong, Keh Kiong; Ting, Kit Cheng; Chow, Yeow Leng

    2018-01-01

    To understand the perceptions of critical care nurses towards providing end-of-life care. There has been an increasing interest in end-of-life care in the critical care setting. In Singapore, approximately half of deaths in the hospital occur during critical care. While nurses are well positioned to provide end-of-life care to patients and their family members, they faced barriers to providing end-of-life care. Also, providing end-of-life care has profound positive and negative psychological effects on nurses, with the latter being more prominent. Qualitative descriptive design. Data collection was performed in a medical intensive care unit of a public tertiary hospital in Singapore. Ten registered nurses were purposively sampled and interviewed individually using a semi-structured interview guide. A codebook was developed to guide coding, and data were thematically analysed. Rigour was maintained. Nurses went through a trajectory of experience. They experienced the culture of care and developed dissatisfaction with it. The tension shaped their perception and meaning of life and death, and they developed mechanisms to reach resolution. This study provides insight on nurses' perception as a trajectory of experience and raised several implications on clinical practice, policy and research. There is a need to alleviate the tension nurses face and to facilitate coming to terms with the tension by improving the culture of care and supporting nurses. Nurses could be involved more in decision-making and empowered to start end-of-life care conversations within the team and with family members. Communication with family members and between nurses and doctors could be improved. Support for nurses providing end-of-life care could be enhanced through promoting social networks, education and bereavement support. Further research is needed to explore ways to support and empower nurses to provide end-of-life care in critical care. © 2017 John Wiley & Sons Ltd.

  5. The Effect of an Electronic Checklist on Critical Care Provider Workload, Errors, and Performance.

    Science.gov (United States)

    Thongprayoon, Charat; Harrison, Andrew M; O'Horo, John C; Berrios, Ronaldo A Sevilla; Pickering, Brian W; Herasevich, Vitaly

    2016-03-01

    The strategy used to improve effective checklist use in intensive care unit (ICU) setting is essential for checklist success. This study aimed to test the hypothesis that an electronic checklist could reduce ICU provider workload, errors, and time to checklist completion, as compared to a paper checklist. This was a simulation-based study conducted at an academic tertiary hospital. All participants completed checklists for 6 ICU patients: 3 using an electronic checklist and 3 using an identical paper checklist. In both scenarios, participants had full access to the existing electronic medical record system. The outcomes measured were workload (defined using the National Aeronautics and Space Association task load index [NASA-TLX]), the number of checklist errors, and time to checklist completion. Two independent clinician reviewers, blinded to participant results, served as the reference standard for checklist error calculation. Twenty-one ICU providers participated in this study. This resulted in the generation of 63 simulated electronic checklists and 63 simulated paper checklists. The median NASA-TLX score was 39 for the electronic checklist and 50 for the paper checklist (P = .005). The median number of checklist errors for the electronic checklist was 5, while the median number of checklist errors for the paper checklist was 8 (P = .003). The time to checklist completion was not significantly different between the 2 checklist formats (P = .76). The electronic checklist significantly reduced provider workload and errors without any measurable difference in the amount of time required for checklist completion. This demonstrates that electronic checklists are feasible and desirable in the ICU setting. © The Author(s) 2014.

  6. Vison excitations in near-critical quantum dimer models

    Science.gov (United States)

    Strübi, G.; Ivanov, D. A.

    2011-06-01

    We study vison excitations in a quantum dimer model interpolating between the Rokhsar-Kivelson models on the square and triangular lattices. In the square-lattice case, the model is known to be critical and characterized by U(1) topological quantum numbers. Introducing diagonal dimers brings the model to a Z2 resonating-valence-bond phase. We study variationally the emergence of vison excitations at low concentration of diagonal dimers, close to the critical point. We find that, in this regime, vison excitations are large in size and their structure resembles vortices in type-II superconductors.

  7. Model of Providing Assistive Technologies in Special Education Schools.

    Science.gov (United States)

    Lersilp, Suchitporn; Putthinoi, Supawadee; Chakpitak, Nopasit

    2015-05-14

    Most students diagnosed with disabilities in Thai special education schools received assistive technologies, but this did not guarantee the greatest benefits. The purpose of this study was to survey the provision, use and needs of assistive technologies, as well as the perspectives of key informants regarding a model of providing them in special education schools. The participants were selected by the purposive sampling method, and they comprised 120 students with visual, physical, hearing or intellectual disabilities from four special education schools in Chiang Mai, Thailand; and 24 key informants such as parents or caregivers, teachers, school principals and school therapists. The instruments consisted of an assistive technology checklist and a semi-structured interview. Results showed that a category of assistive technologies was provided for students with disabilities, with the highest being "services", followed by "media" and then "facilities". Furthermore, mostly students with physical disabilities were provided with assistive technologies, but those with visual disabilities needed it more. Finally, the model of providing assistive technologies was composed of 5 components: Collaboration; Holistic perspective; Independent management of schools; Learning systems and a production manual for users; and Development of an assistive technology center, driven by 3 major sources such as Government and Private organizations, and Schools.

  8. Summary of the Supplemental Model Reports Supporting the Disposal Criticality Analysis Methodology Topical Report

    International Nuclear Information System (INIS)

    Brownson, D. A.

    2002-01-01

    The Department of Energy (DOE) Office of Civilian Radioactive Waste Management (OCRWM) has committed to a series of model reports documenting the methodology to be utilized in the Disposal Criticality Analysis Methodology Topical Report (YMP 2000). These model reports detail and provide validation of the methodology to be utilized for criticality analyses related to: (1) Waste form/waste package degradation; (2) Waste package isotopic inventory; (3) Criticality potential of degraded waste form/waste package configurations (effective neutron multiplication factor); (4) Probability of criticality (for each potential critical configuration as well as total event); and (5) Criticality consequences. This purpose of this summary report is to provide a status of the model reports and a schedule for their completion. This report also provides information relative to the model report content and validation. The model reports and their revisions are being generated as a result of: (1) Commitments made in the Disposal Criticality Analysis Methodology Topical Report (YMP 2000); (2) Open Items from the Safety Evaluation Report (Reamer 2000); (3) Key Technical Issue agreements made during DOE/U.S. Nuclear Regulatory Commission (NRC) Technical Exchange Meeting (Reamer and Williams 2000); and (4) NRC requests for additional information (Schlueter 2002)

  9. Application of grey theory in identification model of human error criticality

    International Nuclear Information System (INIS)

    Li Pengcheng; Zhang Li; Wang Yiqun

    2009-01-01

    The identification model for human error criticality is constructed on the basis of the principle of the Failure Mode and Effects Analysis. It consists of three decision-making factors, namely the scale of probability of occurrence of human error mode, the scale of probability of error-effect and the scale of error-consequence criticality. It is difficult to consider the weight of every factor, this paper employs the grey theory to identify the human error criticality, which provides a new viewpoint for the identification of the priority of error criticality and origin, which overcome the problem for the actual weight distribution. (authors)

  10. Modified Critical State Two-Surface Plasticity Model for Sands

    DEFF Research Database (Denmark)

    Sørensen, Kris Wessel; Nielsen, Søren Kjær; Shajarati, Amir

    This article describes the outline of a numerical integration scheme for a critical state two-surface plasticity model for sands. The model is slightly modified by LeBlanc (2008) compared to the original formulation presented by Manzari and Dafalias (1997) and has the ability to correctly model...... the stress-strain response of sands. The model is versatile and can be used to simulate drained and undrained conditions, due to the fact that the model can efficiently calculate change in void ratio as well as pore pressure. The objective of the constitutive model is to investigate if the numerical...

  11. A self-organized criticality model for plasma transport

    International Nuclear Information System (INIS)

    Carreras, B.A.; Newman, D.; Lynch, V.E.

    1996-01-01

    Many models of natural phenomena manifest the basic hypothesis of self-organized criticality (SOC). The SOC concept brings together the self-similarity on space and time scales that is common to many of these phenomena. The application of the SOC modelling concept to the plasma dynamics near marginal stability opens new possibilities of understanding issues such as Bohm scaling, profile consistency, broad band fluctuation spectra with universal characteristics and fast time scales. A model realization of self-organized criticality for plasma transport in a magnetic confinement device is presented. The model is based on subcritical resistive pressure-gradient-driven turbulence. Three-dimensional nonlinear calculations based on this model show the existence of transport under subcritical conditions. This model that includes fluctuation dynamics leads to results very similar to the running sandpile paradigm

  12. A logical model provides insights into T cell receptor signaling.

    Directory of Open Access Journals (Sweden)

    Julio Saez-Rodriguez

    2007-08-01

    Full Text Available Cellular decisions are determined by complex molecular interaction networks. Large-scale signaling networks are currently being reconstructed, but the kinetic parameters and quantitative data that would allow for dynamic modeling are still scarce. Therefore, computational studies based upon the structure of these networks are of great interest. Here, a methodology relying on a logical formalism is applied to the functional analysis of the complex signaling network governing the activation of T cells via the T cell receptor, the CD4/CD8 co-receptors, and the accessory signaling receptor CD28. Our large-scale Boolean model, which comprises 94 nodes and 123 interactions and is based upon well-established qualitative knowledge from primary T cells, reveals important structural features (e.g., feedback loops and network-wide dependencies and recapitulates the global behavior of this network for an array of published data on T cell activation in wild-type and knock-out conditions. More importantly, the model predicted unexpected signaling events after antibody-mediated perturbation of CD28 and after genetic knockout of the kinase Fyn that were subsequently experimentally validated. Finally, we show that the logical model reveals key elements and potential failure modes in network functioning and provides candidates for missing links. In summary, our large-scale logical model for T cell activation proved to be a promising in silico tool, and it inspires immunologists to ask new questions. We think that it holds valuable potential in foreseeing the effects of drugs and network modifications.

  13. National Water Model: Providing the Nation with Actionable Water Intelligence

    Science.gov (United States)

    Aggett, G. R.; Bates, B.

    2017-12-01

    The National Water Model (NWM) provides national, street-level detail of water movement through time and space. Operating hourly, this flood of information offers enormous benefits in the form of water resource management, natural disaster preparedness, and the protection of life and property. The Geo-Intelligence Division at the NOAA National Water Center supplies forecasters and decision-makers with timely, actionable water intelligence through the processing of billions of NWM data points every hour. These datasets include current streamflow estimates, short and medium range streamflow forecasts, and many other ancillary datasets. The sheer amount of NWM data produced yields a dataset too large to allow for direct human comprehension. As such, it is necessary to undergo model data post-processing, filtering, and data ingestion by visualization web apps that make use of cartographic techniques to bring attention to the areas of highest urgency. This poster illustrates NWM output post-processing and cartographic visualization techniques being developed and employed by the Geo-Intelligence Division at the NOAA National Water Center to provide national actionable water intelligence.

  14. OBESITY AND CRITICAL ILLNESS: INSIGHTS FROM ANIMAL MODELS.

    Science.gov (United States)

    Mittwede, Peter N; Clemmer, John S; Bergin, Patrick F; Xiang, Lusha

    2016-04-01

    Critical illness is a major cause of morbidity and mortality around the world. While obesity is often detrimental in the context of trauma, it is paradoxically associated with improved outcomes in some septic patients. The reasons for these disparate outcomes are not well understood. A number of animal models have been used to study the obese response to various forms of critical illness. Just as there have been many animal models that have attempted to mimic clinical conditions, there are many clinical scenarios that can occur in the highly heterogeneous critically ill patient population that occupies hospitals and intensive care units. This poses a formidable challenge for clinicians and researchers attempting to understand the mechanisms of disease and develop appropriate therapies and treatment algorithms for specific subsets of patients, including the obese. The development of new, and the modification of existing animal models, is important in order to bring effective treatments to a wide range of patients. Not only do experimental variables need to be matched as closely as possible to clinical scenarios, but animal models with pre-existing comorbid conditions need to be studied. This review briefly summarizes animal models of hemorrhage, blunt trauma, traumatic brain injury, and sepsis. It also discusses what has been learned through the use of obese models to study the pathophysiology of critical illness in light of what has been demonstrated in the clinical literature.

  15. Providing critical care patients with a personalised discharge summary: a questionnaire survey and retrospective analysis exploring feasibility and effectiveness.

    Science.gov (United States)

    Bench, Suzanne D; Heelas, Karina; White, Catherine; Griffiths, Peter

    2014-04-01

    This paper reports on the potential value and feasibility of providing patients with a personalised discharge summary of their critical care stay. Fifty-one patient discharge summaries, written by nurses during a randomised controlled trial, were retrospectively analysed for readability, structure and quality. A questionnaire survey completed by trial patients (n=42), their relatives (n=21) and nurses (n=170) explored user experience and feasibility. Quantitative questionnaire data were analysed descriptively and inferentially; qualitative data were subjected to content analysis. Most completed summaries achieved at least an average readability score and were of an acceptable quality. Motivation, time constraints and competing priorities were identified as key barriers to writing an effective summary; however, in the majority of cases, writing them had taken less than 15 minutes. Questionnaire data support that patient discharge summaries can help patients, relatives and ward nurses better understand and patients accept, what happened in critical care. Patient discharge summaries are likely to be a useful adjunct to existing discharge information, but further work is required to determine when and how they should be provided. With appropriate training and support, it is feasible for nurses to write discharge summaries in a busy critical care environment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Governance, Government, and the Search for New Provider Models

    Directory of Open Access Journals (Sweden)

    Richard B. Saltman

    2016-01-01

    Full Text Available A central problem in designing effective models of provider governance in health systems has been to ensure an appropriate balance between the concerns of public sector and/or government decision-makers, on the one hand, and of non-governmental health services actors in civil society and private life, on the other. In tax-funded European health systems up to the 1980s, the state and other public sector decision-makers played a dominant role over health service provision, typically operating hospitals through national or regional governments on a command-and-control basis. In a number of countries, however, this state role has started to change, with governments first stepping out of direct service provision and now de facto pushed to focus more on steering provider organizations rather than on direct public management. In this new approach to provider governance, the state has pulled back into a regulatory role that introduces market-like incentives and management structures, which then apply to both public and private sector providers alike. This article examines some of the main operational complexities in implementing this new governance reality/strategy, specifically from a service provision (as opposed to mostly a financing or even regulatory perspective. After briefly reviewing some of the key theoretical dilemmas, the paper presents two case studies where this new approach was put into practice: primary care in Sweden and hospitals in Spain. The article concludes that good governance today needs to reflect practical operational realities if it is to have the desired effect on health sector reform outcome.

  17. Proposition of a multicriteria model to select logistics services providers

    Directory of Open Access Journals (Sweden)

    Miriam Catarina Soares Aharonovitz

    2014-06-01

    Full Text Available This study aims to propose a multicriteria model to select logistics service providers by the development of a decision tree. The methodology consists of a survey, which resulted in a sample of 181 responses. The sample was analyzed using statistic methods, descriptive statistics among them, multivariate analysis, variance analysis, and parametric tests to compare means. Based on these results, it was possible to obtain the decision tree and information to support the multicriteria analysis. The AHP (Analytic Hierarchy Process was applied to determine the data influence and thus ensure better consistency in the analysis. The decision tree categorizes the criteria according to the decision levels (strategic, tactical and operational. Furthermore, it allows to generically evaluate the importance of each criterion in the supplier selection process from the point of view of logistics services contractors.

  18. On the critical behavior of the inverse susceptibility of a model of structural phase transitions

    International Nuclear Information System (INIS)

    Pisanova, E.S.; Ivanov, S.I.

    2013-01-01

    An exactly solvable lattice model describing structural phase transitions in an anharmonic crystal with long-range interaction is considered in the neighborhoods of the quantum and classical critical points at the corresponding upper critical dimensions. In a broader neighborhood of the critical region the inverse susceptibility of the model is exactly calculated in terms of the Lambert W-function and graphically presented as a function of the deviation from the critical point and the upper critical dimension. For quantum and classical systems with real physical dimensions (chains, thin layers and three-dimensional systems) the exact results are compared with the asymptotic ones on the basis of some numerical data for their ratio. Relative errors are also provided

  19. A Modified Critical State Two-surface Plasticity Model for Sand

    DEFF Research Database (Denmark)

    Bakmar, Christian LeBlanc; Hededal, O.; Ibsen, Lars Bo

    This paper provides background information and documentation for the implementation of a robust plasticity model as a user-subroutine in the commercial finite difference code, FLAC3D by Itasca. The plasticity model presented is equal to the 3 dimensional critical state two-surface plasticity model...... for sands by Manzari et al., but uses a modified multi-axial surface formulation based on a versatile shape function prescribing a family of smooth and convex contours in the π-plane. The model is formulated within the framework of critical state soil mechanics and is capable of accurately simulating...

  20. Critical Infrastructure Protection and Resilience Literature Survey: Modeling and Simulation

    Science.gov (United States)

    2014-11-01

    Application (NESEA); 13-14 Dec, 2012; Liverpool , UK. 16. Brandon R, Page S, Varndell J. Real-Time threat assessment for critical infrastructure protection...International Journal of Risk Assessment and Management. 2006;6(4-6):423-439. 32. Zale JJ KB. A GIS-based football stadium evacuation model

  1. Interpretive and Critical Phenomenological Crime Studies: A Model Design

    Science.gov (United States)

    Miner-Romanoff, Karen

    2012-01-01

    The critical and interpretive phenomenological approach is underutilized in the study of crime. This commentary describes this approach, guided by the question, "Why are interpretive phenomenological methods appropriate for qualitative research in criminology?" Therefore, the purpose of this paper is to describe a model of the interpretive…

  2. Critical properties of a three dimension p-spin model

    International Nuclear Information System (INIS)

    Franz, S.; Parisi, G.

    2000-03-01

    In this paper we study the critical properties of a finite dimensional generalization of the p-spin model. We find evidence that in dimension three, contrary to its mean field limit, the glass transition is associated to a diverging susceptibility (and correlation length). (author)

  3. Uncertainty modelling of critical column buckling for reinforced ...

    Indian Academy of Sciences (India)

    ances the accuracy of the structural models by using experimental results and design codes. (Baalbaki et al 1991; ... in calculation of column buckling load as defined in the following section. 4. Fuzzy logic ... material uncertainty, using the value becomes a critical solution and is a more accurate and safe method compared ...

  4. Theoretical Models of Deliberative Democracy: A Critical Analysis

    Directory of Open Access Journals (Sweden)

    Tutui Viorel

    2015-07-01

    Full Text Available Abstract: My paper focuses on presenting and analyzing some of the most important theoretical models of deliberative democracy and to emphasize their limits. Firstly, I will mention James Fishkin‟s account of deliberative democracy and its relations with other democratic models. He differentiates between four democratic theories: competitive democracy, elite deliberation, participatory democracy and deliberative democracy. Each of these theories makes an explicit commitment to two of the following four “principles”: political equality, participation, deliberation, nontyranny. Deliberative democracy is committed to political equality and deliberation. Secondly, I will present Philip Pettit‟s view concerning the main constraints of deliberative democracy: the inclusion constraint, the judgmental constraint and the dialogical constraint. Thirdly, I will refer to Amy Gutmann and Dennis Thompson‟s conception regarding the “requirements” or characteristics of deliberative democracy: the reason-giving requirement, the accessibility of reasons, the binding character of the decisions and the dynamic nature of the deliberative process. Finally, I will discuss Joshua Cohen‟s “ideal deliberative procedure” which has the following features: it is free, reasoned, the parties are substantively equal and the procedure aims to arrive at rationally motivated consensus. After presenting these models I will provide a critical analysis of each one of them with the purpose of revealing their virtues and limits. I will make some suggestions in order to combine the virtues of these models, to transcend their limitations and to offer a more systematical account of deliberative democracy. In the next four sections I will take into consideration four main strategies for combining political and epistemic values (“optimistic”, “deliberative”, “democratic” and “pragmatic” and the main objections they have to face. In the concluding section

  5. Current algebra of WZNW models at and away from criticality

    International Nuclear Information System (INIS)

    Abdalla, E.; Forger, M.

    1992-01-01

    In this paper, the authors derive the current algebra of principal chiral models with a Wess-Zumino term. At the critical coupling where the model becomes conformally invariant (Wess-Zumino-Novikov-Witten theory), this algebra reduces to two commuting Kac-Moody algebras, while in the limit where the coupling constant is taken to zero (ordinary chiral model), we recover the current algebra of that model. In this way, the latter is explicitly realized as a deformation of the former, with the coupling constant as the deformation parameter

  6. Self-organized Criticality Model for Ocean Internal Waves

    International Nuclear Information System (INIS)

    Wang Gang; Hou Yijun; Lin Min; Qiao Fangli

    2009-01-01

    In this paper, we present a simple spring-block model for ocean internal waves based on the self-organized criticality (SOC). The oscillations of the water blocks in the model display power-law behavior with an exponent of -2 in the frequency domain, which is similar to the current and sea water temperature spectra in the actual ocean and the universal Garrett and Munk deep ocean internal wave model [Geophysical Fluid Dynamics 2 (1972) 225; J. Geophys. Res. 80 (1975) 291]. The influence of the ratio of the driving force to the spring coefficient to SOC behaviors in the model is also discussed. (general)

  7. The critical domain size of stochastic population models.

    Science.gov (United States)

    Reimer, Jody R; Bonsall, Michael B; Maini, Philip K

    2017-02-01

    Identifying the critical domain size necessary for a population to persist is an important question in ecology. Both demographic and environmental stochasticity impact a population's ability to persist. Here we explore ways of including this variability. We study populations with distinct dispersal and sedentary stages, which have traditionally been modelled using a deterministic integrodifference equation (IDE) framework. Individual-based models (IBMs) are the most intuitive stochastic analogues to IDEs but yield few analytic insights. We explore two alternate approaches; one is a scaling up to the population level using the Central Limit Theorem, and the other a variation on both Galton-Watson branching processes and branching processes in random environments. These branching process models closely approximate the IBM and yield insight into the factors determining the critical domain size for a given population subject to stochasticity.

  8. A Quasispecies Continuous Contact Model in a Critical Regime

    Science.gov (United States)

    Kondratiev, Yuri; Pirogov, Sergey; Zhizhina, Elena

    2016-04-01

    We study a new non-equilibrium dynamical model: a marked continuous contact model in d-dimensional space (d ge 3). We prove that for certain values of rates (the critical regime) this system has the one-parameter family of invariant measures labelled by the spatial density of particles. Then we prove that the process starting from the marked Poisson measure converges to one of these invariant measures. In contrast with the continuous contact model studied earlier in Kondratiev (Infin Dimens Anal Quantum Probab Relat Top 11(2):231-258, 2008), now the spatial particle density is not a conserved quantity.

  9. Do Lumped-Parameter Models Provide the Correct Geometrical Damping?

    DEFF Research Database (Denmark)

    Andersen, Lars

    This paper concerns the formulation of lumped-parameter models for rigid footings on homogenous or stratified soil. Such models only contain a few degrees of freedom, which makes them ideal for inclusion in aero-elastic codes for wind turbines and other models applied to fast evaluation of struct......This paper concerns the formulation of lumped-parameter models for rigid footings on homogenous or stratified soil. Such models only contain a few degrees of freedom, which makes them ideal for inclusion in aero-elastic codes for wind turbines and other models applied to fast evaluation...... response during excitation and the geometrical damping related to free vibrations of a hexagonal footing. The optimal order of a lumped-parameter model is determined for each degree of freedom, i.e. horizontal and vertical translation as well as torsion and rocking. In particular, the necessity of coupling...

  10. The effect of sensory stimulation provided by family on arterial blood oxygen saturation in critical care patients.

    Science.gov (United States)

    Yousefi, Hojatollah; Naderi, Mojgan; Daryabeigi, Reza

    2015-01-01

    Stressors in the intensive care unit (ICU) impair patients' comfort, excite the stress response, and increase oxygen consumption in their body. Non-medical interventions are recommended by several studies as a treatment to improve comfort in the ICU patients. Sensory stimulation is one of the most important interventions. Since arterial blood oxygen saturation is an important index of patients' clinical and respiratory condition, this study aimed to investigate the effect of sensory stimulation provided by family on arterial blood oxygen saturation in critical care patients. This study is a clinical trial conducted on 64 patients hospitalized in the ICU wards of Al-Zahra and Kashani hospitals in Isfahan, Iran in 2012 and 2013. The patients were selected by simple sampling method and were randomly assigned to two groups (study and control). Patients' arterial blood oxygen saturations were measured 10 min before, immediately after, 10 min and 30 min after sensory stimulation in the study group, and simultaneously in the control group without any intervention. Repeated measures analysis of variance (ANOVA) showed a significant difference in the mean of arterial blood oxygen saturation levels 10 min before, immediately after, 10 min and 30 min after sensory stimulation in the study group (P 0.18). Application of sensory stimulations as a nursing and non-medical intervention by the family members improves comfort and increases the level of blood oxygen saturation in critical care patients.

  11. Critical exponents for the Reggeon quantum spin model

    International Nuclear Information System (INIS)

    Brower, R.C.; Furman, M.A.

    1978-01-01

    The Reggeon quantum spin (RQS) model on the transverse lattice in D dimensional impact parameter space has been conjectured to have the same critical behaviour as the Reggeon field theory (RFT). Thus from a high 'temperature' series of ten (D=2) and twenty (D=1) terms for the RQS model the authors extrapolate to the critical temperature T=Tsub(c) by Pade approximants to obtain the exponents eta=0.238 +- 0.008, z=1.16 +- 0.01, γ=1.271 +- 0.007 for D=2 and eta=0.317 +- 0.002, z=1.272 +- 0.007, γ=1.736 +- 0.001, lambda=0.57 +- 0.03 for D=1. These exponents naturally interpolate between the D=0 and D=4-epsilon results for RFT as expected on the basis of the universality conjecture. (Auth.)

  12. A Comprehensive Assessment Model for Critical Infrastructure Protection

    Directory of Open Access Journals (Sweden)

    Häyhtiö Markus

    2017-12-01

    Full Text Available International business demands seamless service and IT-infrastructure throughout the entire supply chain. However, dependencies between different parts of this vulnerable ecosystem form a fragile web. Assessment of the financial effects of any abnormalities in any part of the network is demanded in order to protect this network in a financially viable way. Contractual environment between the actors in a supply chain, different business domains and functions requires a management model, which enables a network wide protection for critical infrastructure. In this paper authors introduce such a model. It can be used to assess financial differences between centralized and decentralized protection of critical infrastructure. As an end result of this assessment business resilience to unknown threats can be improved across the entire supply chain.

  13. Do Lumped-Parameter Models Provide the Correct Geometrical Damping?

    DEFF Research Database (Denmark)

    Andersen, Lars

    2007-01-01

    This paper concerns the formulation of lumped-parameter models for rigid footings on homogenous or stratified soil with focus on the horizontal sliding and rocking. Such models only contain a few degrees of freedom, which makes them ideal for inclusion in aero-elastic codes for wind turbines......-parameter models with respect to the prediction of the maximum response during excitation and the geometrical damping related to free vibrations of a footing....

  14. Genus-two correlators for critical Ising model

    International Nuclear Information System (INIS)

    Behera, N.; Malik, R.P.; Kaul, R.K.

    1989-01-01

    The characters and one- and two-point correlators for the critical Ising model on a genus-two Riemann surface have been obtained using their modular transformation properties and the factorization properties in the pinching limit of the zero-homology cycle of the surface. The procedure can easily be generalized to higher-genus Riemann surfaces and also to other rational conformal field theories

  15. Development of a neural network model for predicting glucose levels in a surgical critical care setting

    Directory of Open Access Journals (Sweden)

    Pappada Scott M

    2010-09-01

    Full Text Available Abstract Development of neural network models for the prediction of glucose levels in critically ill patients through the application of continuous glucose monitoring may provide enhanced patient outcomes. Here we demonstrate the utilization of a predictive model in real-time bedside monitoring. Such modeling may provide intelligent/directed therapy recommendations, guidance, and ultimately automation, in the near future as a means of providing optimal patient safety and care in the provision of insulin drips to prevent hyperglycemia and hypoglycemia.

  16. Model-based automated testing of critical PLC programs.

    CERN Document Server

    Fernández Adiego, B; Tournier, J-C; González Suárez, V M; Bliudze, S

    2014-01-01

    Testing of critical PLC (Programmable Logic Controller) programs remains a challenging task for control system engineers as it can rarely be automated. This paper proposes a model based approach which uses the BIP (Behavior, Interactions and Priorities) framework to perform automated testing of PLC programs developed with the UNICOS (UNified Industrial COntrol System) framework. This paper defines the translation procedure and rules from UNICOS to BIP which can be fully automated in order to hide the complexity of the underlying model from the control engineers. The approach is illustrated and validated through the study of a water treatment process.

  17. CRITICAL CURVES AND CAUSTICS OF TRIPLE-LENS MODELS

    International Nuclear Information System (INIS)

    Daněk, Kamil; Heyrovský, David

    2015-01-01

    Among the 25 planetary systems detected up to now by gravitational microlensing, there are two cases of a star with two planets, and two cases of a binary star with a planet. Other, yet undetected types of triple lenses include triple stars or stars with a planet with a moon. The analysis and interpretation of such events is hindered by the lack of understanding of essential characteristics of triple lenses, such as their critical curves and caustics. We present here analytical and numerical methods for mapping the critical-curve topology and caustic cusp number in the parameter space of n-point-mass lenses. We apply the methods to the analysis of four symmetric triple-lens models, and obtain altogether 9 different critical-curve topologies and 32 caustic structures. While these results include various generic types, they represent just a subset of all possible triple-lens critical curves and caustics. Using the analyzed models, we demonstrate interesting features of triple lenses that do not occur in two-point-mass lenses. We show an example of a lens that cannot be described by the Chang–Refsdal model in the wide limit. In the close limit we demonstrate unusual structures of primary and secondary caustic loops, and explain the conditions for their occurrence. In the planetary limit we find that the presence of a planet may lead to a whole sequence of additional caustic metamorphoses. We show that a pair of planets may change the structure of the primary caustic even when placed far from their resonant position at the Einstein radius

  18. Model organoids provide new research opportunities for ductal pancreatic cancer

    NARCIS (Netherlands)

    Boj, Sylvia F|info:eu-repo/dai/nl/304074799; Hwang, Chang-Il; Baker, Lindsey A; Engle, Dannielle D; Tuveson, David A; Clevers, Hans|info:eu-repo/dai/nl/07164282X

    We recently established organoid models from normal and neoplastic murine and human pancreas tissues. These organoids exhibit ductal- and disease stage-specific characteristics and, after orthotopic transplantation, recapitulate the full spectrum of tumor progression. Pancreatic organoid technology

  19. Lyapunov exponent and criticality in the Hamiltonian mean field model

    Science.gov (United States)

    Filho, L. H. Miranda; Amato, M. A.; Rocha Filho, T. M.

    2018-03-01

    We investigate the dependence of the largest Lyapunov exponent (LLE) of an N-particle self-gravitating ring model at equilibrium with respect to the number of particles and its dependence on energy. This model has a continuous phase-transition from a ferromagnetic to homogeneous phase, and we numerically confirm with large scale simulations the existence of a critical exponent associated to the LLE, although at variance with the theoretical estimate. The existence of strong chaos in the magnetized state evidenced by a positive Lyapunov exponent is explained by the coupling of individual particle oscillations to the diffusive motion of the center of mass of the system and also results in a change of the scaling of the LLE with the number of particles. We also discuss thoroughly for the model the validity and limits of the approximations made by a geometrical model for their analytic estimate.

  20. Homogeneous non-equilibrium two-phase critical flow model

    International Nuclear Information System (INIS)

    Schroeder, J.J.; Vuxuan, N.

    1987-01-01

    An important aspect of nuclear and chemical reactor safety is the ability to predict the maximum or critical mass flow rate from a break or leak in a pipe system. At the beginning of such a blowdown, if the stagnation condition of the fluid is subcooled or slightly saturated thermodynamic non-equilibrium exists in the downstream, e.g. the fluid becomes superheated to a degree determined by the liquid pressure. A simplified non-equilibrium model, explained in this report, is valid for rapidly decreasing pressure along the flow path. It presumes that fluid has to be superheated by an amount governed by physical principles before it starts to flash into steam. The flow is assumed to be homogeneous, i.e. the steam and liquid velocities are equal. An adiabatic flow calculation mode (Fanno lines) is employed to evaluate the critical flow rate for long pipes. The model is found to satisfactorily describe critical flow tests. Good agreement is obtained with the large scale Marviken tests as well as with small scale experiments. (orig.)

  1. Conceptual Models of the Individual Public Service Provider

    DEFF Research Database (Denmark)

    Andersen, Lotte Bøgh; Bhatti, Yosef; Petersen, Ole Helby

    Individual public service providers’ motivation can be conceptualized as either extrinsic, autonomous or prosocial, and the question is how we can best theoretically understand this complexity without losing too much coherence and parsimony. Drawing on Allison’s approach (1969), three perspectives...... are used to gain insight on the motivation of public service providers; namely principal-agent theory, self-determination theory and public service motivation theory. We situate the theoretical discussions in the context of public service providers being transferred to private organizations...... as a consequence of outsourcing by the public sector. Although this empirical setting is interesting in itself, here it serves primarily as grist for a wider discussion on strategies for applying multiple theoretical approaches and crafting a theoretical synthesis. The key contribution of the paper is thus...

  2. A critical review of lexical analysis and Big Five model

    Directory of Open Access Journals (Sweden)

    María Cristina Richaud de Minzi

    2002-06-01

    Full Text Available In the last years the idea has resurfaced that traits can be measured in a reliable and valid and this can be useful inthe prediction of human behavior. The five-factor model appears to represent a conceptual and empirical advances in the field of personality theory. Necessary orthogonal factors (Goldberg, 1992, p. 26 to show the relationships between the descriptors of the features in English is five, and its nature can be summarized through the broad concepts of Surgency, Agreeableness, Responsibility, Emotional Stability versus neuroticism and openness to experience (John, 1990, p96 Furthermore, despite the criticisms that have been given to the model, represents a breakthrough in the field of personality assessment. This approach means a contribution to the study of personality, without being the integrative model of personality.

  3. Critical behavior of the two-dimensional icosahedron model

    Science.gov (United States)

    Ueda, Hiroshi; Okunishi, Kouichi; Krčmár, Roman; Gendiar, Andrej; Yunoki, Seiji; Nishino, Tomotoshi

    2017-12-01

    In the context of a discrete analog of the classical Heisenberg model, we investigate the critical behavior of the icosahedron model, where the interaction energy is defined as the inner product of neighboring vector spins of unit length pointing to the vertices of the icosahedron. The effective correlation length and magnetization of the model are calculated by means of the corner-transfer-matrix renormalization group (CTMRG) method. A scaling analysis with respect to the cutoff dimension m in CTMRG reveals a second-order phase transition characterized by the exponents ν =1.62 ±0.02 and β =0.12 ±0.01 . We also extract the central charge from the classical analog of entanglement entropy as c =1.90 ±0.02 , which cannot be explained by the minimal series of conformal field theory.

  4. Ecosystem-based fishery management: A critical review of concepts and ecological economic models

    OpenAIRE

    Nguyen, Thanh Viet

    2009-01-01

    An ecosystem approach means different things to different people. As a result the concept of ecosystem-based fishery management is evolving and it has no universal definition or consistent application. As regards ecosystem modeling, most economic models of fishery ignore the linkages to lower trophic levels. In particular, environmental data and other bottom-up information is widely disregarded. The objective of this paper is to provide a critical review of concepts and ecological economic mo...

  5. Reliable critical sized defect rodent model for cleft palate research.

    Science.gov (United States)

    Mostafa, Nesrine Z; Doschak, Michael R; Major, Paul W; Talwar, Reena

    2014-12-01

    Suitable animal models are necessary to test the efficacy of new bone grafting therapies in cleft palate surgery. Rodent models of cleft palate are available but have limitations. This study compared and modified mid-palate cleft (MPC) and alveolar cleft (AC) models to determine the most reliable and reproducible model for bone grafting studies. Published MPC model (9 × 5 × 3 mm(3)) lacked sufficient information for tested rats. Our initial studies utilizing AC model (7 × 4 × 3 mm(3)) in 8 and 16 weeks old Sprague Dawley (SD) rats revealed injury to adjacent structures. After comparing anteroposterior and transverse maxillary dimensions in 16 weeks old SD and Wistar rats, virtual planning was performed to modify MPC and AC defects dimensions, taking the adjacent structures into consideration. Modified MPC (7 × 2.5 × 1 mm(3)) and AC (5 × 2.5 × 1 mm(3)) defects were employed in 16 weeks old Wistar rats and healing was monitored by micro-computed tomography and histology. Maxillary dimensions in SD and Wistar rats were not significantly different. Preoperative virtual planning enhanced postoperative surgical outcomes. Bone healing occurred at defect margin leaving central bone void confirming the critical size nature of the modified MPC and AC defects. Presented modifications for MPC and AC models created clinically relevant and reproducible defects. Copyright © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  6. Simple Model for Identifying Critical Regions in Atrial Fibrillation

    Science.gov (United States)

    Christensen, Kim; Manani, Kishan A.; Peters, Nicholas S.

    2015-01-01

    Atrial fibrillation (AF) is the most common abnormal heart rhythm and the single biggest cause of stroke. Ablation, destroying regions of the atria, is applied largely empirically and can be curative but with a disappointing clinical success rate. We design a simple model of activation wave front propagation on an anisotropic structure mimicking the branching network of heart muscle cells. This integration of phenomenological dynamics and pertinent structure shows how AF emerges spontaneously when the transverse cell-to-cell coupling decreases, as occurs with age, beyond a threshold value. We identify critical regions responsible for the initiation and maintenance of AF, the ablation of which terminates AF. The simplicity of the model allows us to calculate analytically the risk of arrhythmia and express the threshold value of transversal cell-to-cell coupling as a function of the model parameters. This threshold value decreases with increasing refractory period by reducing the number of critical regions which can initiate and sustain microreentrant circuits. These biologically testable predictions might inform ablation therapies and arrhythmic risk assessment.

  7. Self-Organized Criticality in an Anisotropic Earthquake Model

    Science.gov (United States)

    Li, Bin-Quan; Wang, Sheng-Jun

    2018-03-01

    We have made an extensive numerical study of a modified model proposed by Olami, Feder, and Christensen to describe earthquake behavior. Two situations were considered in this paper. One situation is that the energy of the unstable site is redistributed to its nearest neighbors randomly not averagely and keeps itself to zero. The other situation is that the energy of the unstable site is redistributed to its nearest neighbors randomly and keeps some energy for itself instead of reset to zero. Different boundary conditions were considered as well. By analyzing the distribution of earthquake sizes, we found that self-organized criticality can be excited only in the conservative case or the approximate conservative case in the above situations. Some evidence indicated that the critical exponent of both above situations and the original OFC model tend to the same result in the conservative case. The only difference is that the avalanche size in the original model is bigger. This result may be closer to the real world, after all, every crust plate size is different. Supported by National Natural Science Foundation of China under Grant Nos. 11675096 and 11305098, the Fundamental Research Funds for the Central Universities under Grant No. GK201702001, FPALAB-SNNU under Grant No. 16QNGG007, and Interdisciplinary Incubation Project of SNU under Grant No. 5

  8. Experimental studies on power transformer model winding provided with MOVs

    Directory of Open Access Journals (Sweden)

    G.H. Kusumadevi

    2017-05-01

    Full Text Available Surge voltage distribution across a HV transformer winding due to appearance of very fast rise time (rise time of order 1 μs transient voltages is highly non-uniform along the length of the winding for initial time instant of occurrence of surge. In order to achieve nearly uniform initial time instant voltage distribution along the length of the HV winding, investigations have been carried out on transformer model winding. By connecting similar type of metal oxide varistors across sections of HV transformer model winding, it is possible to improve initial time instant surge voltage distribution across length of the HV transformer winding. Transformer windings with α values 5.3, 9.5 and 19 have been analyzed. The experimental studies have been carried out using high speed oscilloscope of good accuracy. The initial time instant voltage distribution across sections of winding with MOV remains nearly uniform along length of the winding. Also results of fault diagnostics carried out with and without connection of MOVs across sections of winding are reported.

  9. Movement as a critical concept in model generation to attain ...

    African Journals Online (AJOL)

    ... and provide guidelines for the operationalisation of a model as a framework of reference for nursing to facilitate the individual faced with mental health challenges as an integral part of wholeness. A model was generated to facilitate the engagement of self through movement, which contributes to and manifests in a mindful ...

  10. Almutairi's Critical Cultural Competence model for a multicultural healthcare environment.

    Science.gov (United States)

    Almutairi, Adel F; Dahinten, V Susan; Rodney, Patricia

    2015-12-01

    The increasing demographic changes of populations in many countries require an approach for managing the complexity of sociocultural differences. Such an approach could help healthcare organizations to address healthcare disparities and inequities, and promote cultural safety for healthcare providers and patients alike. Almutairi's critical cultural competence (CCC) is a comprehensive approach that holds great promise for managing difficulties arising from sociocultural and linguistic issues during cross-cultural interactions. CCC has addressed the limitations of many other cultural competence approaches that have been discussed in the literature. Therefore, the purpose of this study is to define the construct of CCC and the theoretical components of the CCC. © 2015 John Wiley & Sons Ltd.

  11. A stochastic simulation model for reliable PV system sizing providing for solar radiation fluctuations

    International Nuclear Information System (INIS)

    Kaplani, E.; Kaplanis, S.

    2012-01-01

    Highlights: ► Solar radiation data for European cities follow the Extreme Value or Weibull distribution. ► Simulation model for the sizing of SAPV systems based on energy balance and stochastic analysis. ► Simulation of PV Generator-Loads-Battery Storage System performance for all months. ► Minimum peak power and battery capacity required for reliable SAPV sizing for various European cities. ► Peak power and battery capacity reduced by more than 30% for operation 95% success rate. -- Abstract: The large fluctuations observed in the daily solar radiation profiles affect highly the reliability of the PV system sizing. Increasing the reliability of the PV system requires higher installed peak power (P m ) and larger battery storage capacity (C L ). This leads to increased costs, and makes PV technology less competitive. This research paper presents a new stochastic simulation model for stand-alone PV systems, developed to determine the minimum installed P m and C L for the PV system to be energy independent. The stochastic simulation model developed, makes use of knowledge acquired from an in-depth statistical analysis of the solar radiation data for the site, and simulates the energy delivered, the excess energy burnt, the load profiles and the state of charge of the battery system for the month the sizing is applied, and the PV system performance for the entire year. The simulation model provides the user with values for the autonomy factor d, simulating PV performance in order to determine the minimum P m and C L depending on the requirements of the application, i.e. operation with critical or non-critical loads. The model makes use of NASA’s Surface meteorology and Solar Energy database for the years 1990–2004 for various cities in Europe with a different climate. The results obtained with this new methodology indicate a substantial reduction in installed peak power and battery capacity, both for critical and non-critical operation, when compared to

  12. Critical rotation of general-relativistic polytropic models revisited

    Science.gov (United States)

    Geroyannis, V.; Karageorgopoulos, V.

    2013-09-01

    We develop a perturbation method for computing the critical rotational parameter as a function of the equatorial radius of a rigidly rotating polytropic model in the "post-Newtonia approximation" (PNA). We treat our models as "initial value problems" (IVP) of ordinary differential equations in the complex plane. The computations are carried out by the code dcrkf54.f95 (Geroyannis and Valvi 2012 [P1]; modified Runge-Kutta-Fehlberg code of fourth and fifth order for solving initial value problems in the complex plane). Such a complex-plane treatment removes the syndromes appearing in this particular family of IVPs (see e.g. P1, Sec. 3) and allows continuation of the numerical integrations beyond the surface of the star. Thus all the required values of the Lane-Emden function(s) in the post-Newtonian approximation are calculated by interpolation (so avoiding any extrapolation). An interesting point is that, in our computations, we take into account the complete correction due to the gravitational term, and this issue is a remarkable difference compared to the classical PNA. We solve the generalized density as a function of the equatorial radius and find the critical rotational parameter. Our computations are extended to certain other physical characteristics (like mass, angular momentum, rotational kinetic energy, etc). We find that our method yields results comparable with those of other reliable methods. REFERENCE: V.S. Geroyannis and F.N. Valvi 2012, International Journal of Modern Physics C, 23, No 5, 1250038:1-15.

  13. Modeling financial markets by self-organized criticality

    Science.gov (United States)

    Biondo, Alessio Emanuele; Pluchino, Alessandro; Rapisarda, Andrea

    2015-10-01

    We present a financial market model, characterized by self-organized criticality, that is able to generate endogenously a realistic price dynamics and to reproduce well-known stylized facts. We consider a community of heterogeneous traders, composed by chartists and fundamentalists, and focus on the role of informative pressure on market participants, showing how the spreading of information, based on a realistic imitative behavior, drives contagion and causes market fragility. In this model imitation is not intended as a change in the agent's group of origin, but is referred only to the price formation process. We introduce in the community also a variable number of random traders in order to study their possible beneficial role in stabilizing the market, as found in other studies. Finally, we also suggest some counterintuitive policy strategies able to dampen fluctuations by means of a partial reduction of information.

  14. Self-Organized Criticality Theory Model of Thermal Sandpile

    International Nuclear Information System (INIS)

    Peng Xiao-Dong; Qu Hong-Peng; Xu Jian-Qiang; Han Zui-Jiao

    2015-01-01

    A self-organized criticality model of a thermal sandpile is formulated for the first time to simulate the dynamic process with interaction between avalanche events on the fast time scale and diffusive transports on the slow time scale. The main characteristics of the model are that both particle and energy avalanches of sand grains are considered simultaneously. Properties of intermittent transport and improved confinement are analyzed in detail. The results imply that the intermittent phenomenon such as blobs in the low confinement mode as well as edge localized modes in the high confinement mode observed in tokamak experiments are not only determined by the edge plasma physics, but also affected by the core plasma dynamics. (paper)

  15. Models for Microbial Fuel Cells: A critical review

    Science.gov (United States)

    Xia, Chengshuo; Zhang, Daxing; Pedrycz, Witold; Zhu, Yingmin; Guo, Yongxian

    2018-01-01

    Microbial fuel cells (MFCs) have been widely viewed as one of the most promising alternative sources of renewable energy. A recognition of needs of efficient development methods based on multidisciplinary research becomes crucial for the optimization of MFCs. Modeling of MFCs is an effective way for not only gaining a thorough understanding of the effects of operation conditions on the performance of power generation but also becomes of essential interest to the successful implementation of MFCs. The MFC models encompass the underlying reaction process and limiting factors of the MFC. The models come in various forms, such as the mathematical equations or the equivalent circuits. Different modeling focuses and approaches of the MFC have emerged. In this study, we present a state of the art of MFCs modeling; the past modeling methods are reviewed as well. Models and modeling methods are elaborated on based on the classification provided by Mechanism-based models and Application-based models. Mechanisms, advantages, drawbacks, and application fields of different models are illustrated as well. We exhibit a complete and comprehensive exposition of the different models for MFCs and offer further guidance to promote the performance of MFCs.

  16. Hierarchical, model-based risk management of critical infrastructures

    Energy Technology Data Exchange (ETDEWEB)

    Baiardi, F. [Polo G.Marconi La Spezia, Universita di Pisa, Pisa (Italy); Dipartimento di Informatica, Universita di Pisa, L.go B.Pontecorvo 3 56127, Pisa (Italy)], E-mail: f.baiardi@unipi.it; Telmon, C.; Sgandurra, D. [Dipartimento di Informatica, Universita di Pisa, L.go B.Pontecorvo 3 56127, Pisa (Italy)

    2009-09-15

    Risk management is a process that includes several steps, from vulnerability analysis to the formulation of a risk mitigation plan that selects countermeasures to be adopted. With reference to an information infrastructure, we present a risk management strategy that considers a sequence of hierarchical models, each describing dependencies among infrastructure components. A dependency exists anytime a security-related attribute of a component depends upon the attributes of other components. We discuss how this notion supports the formal definition of risk mitigation plan and the evaluation of the infrastructure robustness. A hierarchical relation exists among models that are analyzed because each model increases the level of details of some components in a previous one. Since components and dependencies are modeled through a hypergraph, to increase the model detail level, some hypergraph nodes are replaced by more and more detailed hypergraphs. We show how critical information for the assessment can be automatically deduced from the hypergraph and define conditions that determine cases where a hierarchical decomposition simplifies the assessment. In these cases, the assessment has to analyze the hypergraph that replaces the component rather than applying again all the analyses to a more detailed, and hence larger, hypergraph. We also show how the proposed framework supports the definition of a risk mitigation plan and discuss some indicators of the overall infrastructure robustness. Lastly, the development of tools to support the assessment is discussed.

  17. Hierarchical, model-based risk management of critical infrastructures

    International Nuclear Information System (INIS)

    Baiardi, F.; Telmon, C.; Sgandurra, D.

    2009-01-01

    Risk management is a process that includes several steps, from vulnerability analysis to the formulation of a risk mitigation plan that selects countermeasures to be adopted. With reference to an information infrastructure, we present a risk management strategy that considers a sequence of hierarchical models, each describing dependencies among infrastructure components. A dependency exists anytime a security-related attribute of a component depends upon the attributes of other components. We discuss how this notion supports the formal definition of risk mitigation plan and the evaluation of the infrastructure robustness. A hierarchical relation exists among models that are analyzed because each model increases the level of details of some components in a previous one. Since components and dependencies are modeled through a hypergraph, to increase the model detail level, some hypergraph nodes are replaced by more and more detailed hypergraphs. We show how critical information for the assessment can be automatically deduced from the hypergraph and define conditions that determine cases where a hierarchical decomposition simplifies the assessment. In these cases, the assessment has to analyze the hypergraph that replaces the component rather than applying again all the analyses to a more detailed, and hence larger, hypergraph. We also show how the proposed framework supports the definition of a risk mitigation plan and discuss some indicators of the overall infrastructure robustness. Lastly, the development of tools to support the assessment is discussed.

  18. 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.

  19. Random geometry model in criticality calculations of solutions containing Raschig rings

    International Nuclear Information System (INIS)

    Teng, S.P.; Lindstrom, D.G.

    1979-01-01

    The criticality constants of fissile solutions containing borated Raschig rings are evaluated using the Monte Carlo code KENO IV with various geometry models. In addition to those used by other investigators, a new geometry model, the random geometry model, is presented to simulate the system of randomly oriented Raschig rings in solution. A technique to obtain the material thickness distribution functions of solution and rings for use in the random geometry model is also presented. Comparison between the experimental data and the calculated results using Monte Carlo method with various geometry models indicates that the random geometry model is a reasonable alternative to models previously used in describing the system of Raschig-ring-filled solution. The random geometry model also provides a solution to the problem of describing an array containing Raschig-ring-filled tanks that is not available to techniques using other models

  20. Critically Reflective Pedagogical Model: a Pragmatic Blueprint for Enhancing Learning and Teaching in Construction Disciplines

    Directory of Open Access Journals (Sweden)

    Imriyas Kamardeen

    2015-11-01

    Full Text Available University lecturers who aspire to provide an improved learning experience for their students continually, and be recognised for high quality teaching should embrace a critically reflective practice. Nonetheless, developing as a reflective lecturer is challenging, although there are pedagogical literatures as general guidelines. This study introduces a new pedagogical model of critically reflective practice to simplify the efforts for lecturers and to shorten their journey to becoming effective teachers. A two-phased action research strategy was adopted for the development and validation of the new model. The first phase operationalised the Brookfield’s four-lens framework to create a reflective teaching practice model, which was then validated with a case study in the second phase. The model offers a pragmatic blueprint for lecturers to build a career with sustained quality of teaching, which in turn translates into improved learning experiences for students.

  1. Taurus II Stage Test Simulations: Using Large-Scale CFD Simulations to Provide Critical Insight into Plume Induced Environments During Design

    Science.gov (United States)

    Struzenberg, L. L.; West, J. S.

    2011-01-01

    This paper describes the use of targeted Loci/CHEM CFD simulations to evaluate the effects of a dual-engine first-stage hot-fire test on an evolving integrated launch pad/test article design. This effort was undertaken as a part of the NESC Independent Assessment of the Taurus II Stage Test Series. The underlying conceptual model included development of a series of computational models and simulations to analyze the plume induced environments on the pad, facility structures and test article. A pathfinder simulation was first developed, capable of providing quick-turn around evaluation of plume impingement pressures on the flame deflector. Results from this simulation were available in time to provide data for an ongoing structural assessment of the deflector. The resulting recommendation was available in a timely manner and was incorporated into construction schedule for the new launch stand under construction at Wallops Flight Facility. A series of Reynolds-Averaged Navier-Stokes (RANS) quasi-steady simulations representative of various key elements of the test profile was performed to identify potential concerns with the test configuration and test profile. As required, unsteady Hybrid-RANS/LES simulations were performed, to provide additional insight into critical aspects of the test sequence. Modifications to the test-specific hardware and facility structures thermal protection as well as modifications to the planned hot-fire test profile were implemented based on these simulation results.

  2. Reliability constrained decision model for energy service provider incorporating demand response programs

    International Nuclear Information System (INIS)

    Mahboubi-Moghaddam, Esmaeil; Nayeripour, Majid; Aghaei, Jamshid

    2016-01-01

    Highlights: • The operation of Energy Service Providers (ESPs) in electricity markets is modeled. • Demand response as the cost-effective solution is used for energy service provider. • The market price uncertainty is modeled using the robust optimization technique. • The reliability of the distribution network is embedded into the framework. • The simulation results demonstrate the benefits of robust framework for ESPs. - Abstract: Demand response (DR) programs are becoming a critical concept for the efficiency of current electric power industries. Therefore, its various capabilities and barriers have to be investigated. In this paper, an effective decision model is presented for the strategic behavior of energy service providers (ESPs) to demonstrate how to participate in the day-ahead electricity market and how to allocate demand in the smart distribution network. Since market price affects DR and vice versa, a new two-step sequential framework is proposed, in which unit commitment problem (UC) is solved to forecast the expected locational marginal prices (LMPs), and successively DR program is applied to optimize the total cost of providing energy for the distribution network customers. This total cost includes the cost of purchased power from the market and distributed generation (DG) units, incentive cost paid to the customers, and compensation cost of power interruptions. To obtain compensation cost, the reliability evaluation of the distribution network is embedded into the framework using some innovative constraints. Furthermore, to consider the unexpected behaviors of the other market participants, the LMP prices are modeled as the uncertainty parameters using the robust optimization technique, which is more practical compared to the conventional stochastic approach. The simulation results demonstrate the significant benefits of the presented framework for the strategic performance of ESPs.

  3. Critical behavior of the Ising model on random fractals.

    Science.gov (United States)

    Monceau, Pascal

    2011-11-01

    We study the critical behavior of the Ising model in the case of quenched disorder constrained by fractality on random Sierpinski fractals with a Hausdorff dimension d(f) is approximately equal to 1.8928. This is a first attempt to study a situation between the borderline cases of deterministic self-similarity and quenched randomness. Intensive Monte Carlo simulations were carried out. Scaling corrections are much weaker than in the deterministic cases, so that our results enable us to ensure that finite-size scaling holds, and that the critical behavior is described by a new universality class. The hyperscaling relation is compatible with an effective dimension equal to the Hausdorff one; moreover the two eigenvalues exponents of the renormalization flows are shown to be different from the ones calculated from ε expansions, and from the ones obtained for fourfold symmetric deterministic fractals. Although the space dimensionality is not integer, lack of self-averaging properties exhibits some features very close to the ones of a random fixed point associated with a relevant disorder.

  4. Universality away from critical points in a thermostatistical model

    Science.gov (United States)

    Lapilli, C. M.; Wexler, C.; Pfeifer, P.

    Nature uses phase transitions as powerful regulators of processes ranging from climate to the alteration of phase behavior of cell membranes to protect cells from cold, building on the fact that thermodynamic properties of a solid, liquid, or gas are sensitive fingerprints of intermolecular interactions. The only known exceptions from this sensitivity are critical points. At a critical point, two phases become indistinguishable and thermodynamic properties exhibit universal behavior: systems with widely different intermolecular interactions behave identically. Here we report a major counterexample. We show that different members of a family of two-dimensional systems —the discrete p-state clock model— with different Hamiltonians describing different microscopic interactions between molecules or spins, may exhibit identical thermodynamic behavior over a wide range of temperatures. The results generate a comprehensive map of the phase diagram of the model and, by virtue of the discrete rotors behaving like continuous rotors, an emergent symmetry, not present in the Hamiltonian. This symmetry, or many-to-one map of intermolecular interactions onto thermodynamic states, demonstrates previously unknown limits for macroscopic distinguishability of different microscopic interactions.

  5. Thermodynamic quantum critical behavior of the anisotropic Kondo necklace model

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, D. [Centro Brasileiro de Pesquisas Fisicas, Rua Dr. Xavier Sigaud, 150-Urca, 22290-180 RJ (Brazil)], E-mail: daniel@cbpf.br; Continentino, M.A. [Instituto de Fisica, Universidade Federal Fluminense, Campus da Praia Vermelha, Niteroi, RJ 24.210-340 (Brazil); Wang Hanting [Beijing National Laboratory of Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)

    2009-03-15

    The Ising-like anisotropy parameter {delta} in the Kondo necklace model is analyzed using the bond-operator method at zero and finite temperatures for arbitrary d dimensions. A decoupling scheme on the double time Green's functions is used to find the dispersion relation for the excitations of the system. At zero temperature and in the paramagnetic side of the phase diagram, we determine the spin gap exponent {nu}z{approx}0.5 in three dimensions and anisotropy between 0{<=}{delta}{<=}1, a result consistent with the dynamic exponent z=1 for the Gaussian character of the bond-operator treatment. On the other hand, in the antiferromagnetic phase at low but finite temperatures, the line of Neel transitions is calculated for {delta}<<1. For d>2 it is only re-normalized by the anisotropy parameter and varies with the distance to the quantum critical point (QCP) |g| as, T{sub N}{proportional_to}|g|{sup {psi}} where the shift exponent {psi}=1/(d-1). Nevertheless, in two dimensions, a long-range magnetic order occurs only at T=0 for any {delta}<<1. In the paramagnetic phase, we also find a power law temperature dependence on the specific heat at the quantum critical trajectoryJ/t=(J/t){sub c}, T{yields}0. It behaves as C{sub V}{proportional_to}T{sup d} for {delta}{<=}1 and {approx}1, in concordance with the scaling theory for z=1.

  6. The Critical Point Entanglement and Chaos in the Dicke Model

    Directory of Open Access Journals (Sweden)

    Lina Bao

    2015-07-01

    Full Text Available Ground state properties and level statistics of the Dicke model for a finite number of atoms are investigated based on a progressive diagonalization scheme (PDS. Particle number statistics, the entanglement measure and the Shannon information entropy at the resonance point in cases with a finite number of atoms as functions of the coupling parameter are calculated. It is shown that the entanglement measure defined in terms of the normalized von Neumann entropy of the reduced density matrix of the atoms reaches its maximum value at the critical point of the quantum phase transition where the system is most chaotic. Noticeable change in the Shannon information entropy near or at the critical point of the quantum phase transition is also observed. In addition, the quantum phase transition may be observed not only in the ground state mean photon number and the ground state atomic inversion as shown previously, but also in fluctuations of these two quantities in the ground state, especially in the atomic inversion fluctuation.

  7. Acute liver failure: a critical appraisal of available animal models.

    Science.gov (United States)

    Bélanger, Mireille; Butterworth, Roger F

    2005-12-01

    The availability of adequate experimental models of acute liver failure (ALF) is of prime importance to provide a better understanding of this condition and allow the development and testing of new therapeutic approaches for patients with ALF. However, the numerous etiologies and complications of ALF contribute to the complexity of this condition and render the development of an ideal experimental model of ALF more difficult than expected. Instead, a number of different models that may be used for the study of specific aspects of ALF have been developed. The most common approaches used to induce ALFin experimental animals are surgical procedures, toxic liver injury,or a combination of both. Despite the high prevalence of viral hepatitis worldwide, very few satisfactory viral models of ALF are available. Established and newly developed models of ALF are reviewed.

  8. Does difficulty functioning in the surrogate role equate to vulnerability in critical illness research? Use of path analysis to examine the relationship between difficulty providing substituted judgment and receptivity to critical illness research participation.

    Science.gov (United States)

    Clarridge, Brian R; Bolcic-Jankovic, Dragana; LeBlanc, Jessica; Mahmood, Rumel S; Kennedy, Carie R; Freeman, Bradley D

    2015-12-01

    Individuals who struggle to provide substitute judgment for the critically ill often find it challenging to engage in decision making for therapeutic interventions. Although essential to the conduct of research, how these individuals respond to requests for clinical trial participation is poorly understood. Survey data collected to examine surrogate attitudes toward research provided the conceptual framework to explore influences on decision making. Path analysis was used to derive the final model (nonlatent, fully recursive, 1 indicator/variable). Surrogates with list-wise complete records (406) were analyzed. The following variables were not retained in the final model: education, income, religiosity, decision-making experience, discussion of patient's wishes, number of individuals assisting with decision making, trust in care providers, difficulty making decisions, and responsibility for decision making. Being white and having experience making treatment decisions for the patient during the current intensive care unit encounter affected the likelihood the surrogate would permit participation in research positively (parameter estimates, 0.281 and 0.06, respectively). No variable reflecting difficulty functioning in the surrogate role was associated with permitting research participation. We were unable to demonstrate a relationship between perceived difficulty in decision making in the surrogate role and receptivity to clinical trial participation. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Critical, statistical, and thermodynamical properties of lattice models

    Energy Technology Data Exchange (ETDEWEB)

    Varma, Vipin Kerala

    2013-10-15

    In this thesis we investigate zero temperature and low temperature properties - critical, statistical and thermodynamical - of lattice models in the contexts of bosonic cold atom systems, magnetic materials, and non-interacting particles on various lattice geometries. We study quantum phase transitions in the Bose-Hubbard model with higher body interactions, as relevant for optical lattice experiments of strongly interacting bosons, in one and two dimensions; the universality of the Mott insulator to superfluid transition is found to remain unchanged for even large three body interaction strengths. A systematic renormalization procedure is formulated to fully re-sum these higher (three and four) body interactions into the two body terms. In the strongly repulsive limit, we analyse the zero and low temperature physics of interacting hard-core bosons on the kagome lattice at various fillings. Evidence for a disordered phase in the Ising limit of the model is presented; in the strong coupling limit, the transition between the valence bond solid and the superfluid is argued to be first order at the tip of the solid lobe.

  10. Critical, statistical, and thermodynamical properties of lattice models

    International Nuclear Information System (INIS)

    Varma, Vipin Kerala

    2013-10-01

    In this thesis we investigate zero temperature and low temperature properties - critical, statistical and thermodynamical - of lattice models in the contexts of bosonic cold atom systems, magnetic materials, and non-interacting particles on various lattice geometries. We study quantum phase transitions in the Bose-Hubbard model with higher body interactions, as relevant for optical lattice experiments of strongly interacting bosons, in one and two dimensions; the universality of the Mott insulator to superfluid transition is found to remain unchanged for even large three body interaction strengths. A systematic renormalization procedure is formulated to fully re-sum these higher (three and four) body interactions into the two body terms. In the strongly repulsive limit, we analyse the zero and low temperature physics of interacting hard-core bosons on the kagome lattice at various fillings. Evidence for a disordered phase in the Ising limit of the model is presented; in the strong coupling limit, the transition between the valence bond solid and the superfluid is argued to be first order at the tip of the solid lobe.

  11. Critical ingredients of Type Ia supernova radiative-transfer modelling

    Science.gov (United States)

    Dessart, Luc; Hillier, D. John; Blondin, Stéphane; Khokhlov, Alexei

    2014-07-01

    We explore the physics of Type Ia supernova (SN Ia) light curves and spectra using the 1D non-local thermodynamic equilibrium (non-LTE) time-dependent radiative-transfer code CMFGEN. Rather than adjusting ejecta properties to match observations, we select as input one `standard' 1D Chandrasekhar-mass delayed-detonation hydrodynamical model, and then explore the sensitivity of radiation and gas properties of the ejecta on radiative-transfer modelling assumptions. The correct computation of SN Ia radiation is not exclusively a solution to an `opacity problem', characterized by the treatment of a large number of lines. We demonstrate that the key is to identify and treat important atomic processes consistently. This is not limited to treating line blanketing in non-LTE. We show that including forbidden-line transitions of metals, and in particular Co, is increasingly important for the temperature and ionization of the gas beyond maximum light. Non-thermal ionization and excitation are also critical since they affect the colour evolution and the ΔM15 decline rate of our model. While impacting little the bolometric luminosity, a more complete treatment of decay routes leads to enhanced line blanketing, e.g. associated with 48Ti in the U and B bands. Overall, we find that SN Ia radiation properties are influenced in a complicated way by the atomic data we employ, so that obtaining converged results is a real challenge. Nonetheless, with our fully fledged CMFGEN model, we obtain good agreement with the golden standard Type Ia SN 2005cf in the optical and near-IR, from 5 to 60 d after explosion, suggesting that assuming spherical symmetry is not detrimental to SN Ia radiative-transfer modelling at these times. Multi-D effects no doubt matter, but they are perhaps less important than accurately treating the non-LTE processes that are crucial to obtain reliable temperature and ionization structures.

  12. Modelling decremental ramps using 2- and 3-parameter "critical power" models.

    Science.gov (United States)

    Morton, R Hugh; Billat, Veronique

    2013-01-01

    The "Critical Power" (CP) model of human bioenergetics provides a valuable way to identify both limits of tolerance to exercise and mechanisms that underpin that tolerance. It applies principally to cycling-based exercise, but with suitable adjustments for analogous units it can be applied to other exercise modalities; in particular to incremental ramp exercise. It has not yet been applied to decremental ramps which put heavy early demand on the anaerobic energy supply system. This paper details cycling-based bioenergetics of decremental ramps using 2- and 3-parameter CP models. It derives equations that, for an individual of known CP model parameters, define those combinations of starting intensity and decremental gradient which will or will not lead to exhaustion before ramping to zero; and equations that predict time to exhaustion on those decremental ramps that will. These are further detailed with suitably chosen numerical and graphical illustrations. These equations can be used for parameter estimation from collected data, or to make predictions when parameters are known.

  13. Ecosystem-based fishery management: a critical review of concepts and ecological economic models

    DEFF Research Database (Denmark)

    Nguyen, Thanh Viet

      An ecosystem approach means different things to different people. As a result the concept of ecosystem-based fishery management is evolving and it has no universal definition or consistent application. As regards ecosystem modeling, most economic models of fishery ignore the linkages to lower...... trophic levels. In particular, environmental data and other bottom-up information is widely disregarded. The objective of this paper is to provide a critical review of concepts and ecological economic models relating to ecosystem-based fishery management....

  14. Techniques and Technology to Revise Content Delivery and Model Critical Thinking in the Neuroscience Classroom.

    Science.gov (United States)

    Illig, Kurt R

    2015-01-01

    Undergraduate neuroscience courses typically involve highly interdisciplinary material, and it is often necessary to use class time to review how principles of chemistry, math and biology apply to neuroscience. Lecturing and Socratic discussion can work well to deliver information to students, but these techniques can lead students to feel more like spectators than participants in a class, and do not actively engage students in the critical analysis and application of experimental evidence. If one goal of undergraduate neuroscience education is to foster critical thinking skills, then the classroom should be a place where students and instructors can work together to develop them. Students learn how to think critically by directly engaging with course material, and by discussing evidence with their peers, but taking classroom time for these activities requires that an instructor find a way to provide course materials outside of class. Using technology as an on-demand provider of course materials can give instructors the freedom to restructure classroom time, allowing students to work together in small groups and to have discussions that foster critical thinking, and allowing the instructor to model these skills. In this paper, I provide a rationale for reducing the use of traditional lectures in favor of more student-centered activities, I present several methods that can be used to deliver course materials outside of class and discuss their use, and I provide a few examples of how these techniques and technologies can help improve learning outcomes.

  15. Modelling critical thinking through learning-oriented assessment ...

    African Journals Online (AJOL)

    In two independent studies, the Cornell Critical Thinking Test – Level Z and the Watson Glaser Critical Thinking Appraisal were administered to gauge the critical thinking abilities of teacher education students. The research results obtained from the two studies will be briefly discussed as evidence that there is a dire need to ...

  16. Critical-Inquiry-Based-Learning: Model of Learning to Promote Critical Thinking Ability of Pre-service Teachers

    Science.gov (United States)

    Prayogi, S.; Yuanita, L.; Wasis

    2018-01-01

    This study aimed to develop Critical-Inquiry-Based-Learning (CIBL) learning model to promote critical thinking (CT) ability of preservice teachers. The CIBL learning model was developed by meeting the criteria of validity, practicality, and effectiveness. Validation of the model involves 4 expert validators through the mechanism of the focus group discussion (FGD). CIBL learning model declared valid to promote CT ability, with the validity level (Va) of 4.20 and reliability (r) of 90,1% (very reliable). The practicality of the model was evaluated when it was implemented that involving 17 of preservice teachers. The CIBL learning model had been declared practice, its measuring from learning feasibility (LF) with very good criteria (LF-score = 4.75). The effectiveness of the model was evaluated from the improvement CT ability after the implementation of the model. CT ability were evaluated using the scoring technique adapted from Ennis-Weir Critical Thinking Essay Test. The average score of CT ability on pretest is - 1.53 (uncritical criteria), whereas on posttest is 8.76 (critical criteria), with N-gain score of 0.76 (high criteria). Based on the results of this study, it can be concluded that developed CIBL learning model is feasible to promote CT ability of preservice teachers.

  17. Critical-ionization model for the dissolution of phenolic polymers in aqueous base

    Science.gov (United States)

    Flanagin, Lewis Wayne

    The microelectronics industry owes much of its success to the miniaturization of the integrated circuit. Advances in the design of photoresists used in microlithography have enabled this progress to continue. The majority of photoresist formulations contain phenolic polymers, and their imaging capabilities arise from the radiation- induced differences in dissolution rate between exposed and unexposed regions of the photoresist in basic aqueous solutions. The Critical-Ionization Model provides an understanding at the molecular level of the important factors in the aqueous dissolution of phenolic polymers below the entanglement molecular weight. The model postulates that a critical fraction of the acidic sites on a phenolic polymer must ionize for the polymer to dissolve in aqueous base. A functional relationship between the dissolution rate and the degree of ionization is developed based on this hypothesis. Quantitative predictions for the effects of polymer structure on the dissolution rate follow from equations relating the degree of ionization to the degree of polymerization, the polymer pKa, and the developer concentration. Experimental verification is' provided through tests of model predictions for the minimum base concentration required for development and the effects of polymer structure on the dissolution rate. Molecular simulations of resist dissolution based on the Critical-Ionization Model are used to probe the mechanism of surface inhibition and the evolution of edge roughness and surface roughness in photoresist profiles. These simulations demonstrate the dependence of the dissolution rate and surface roughness on the molecular-weight distribution of the polymer, degree of deprotection, void fraction, and developer concentration. Model parameters are evaluated using experimental data from turbidimetry, potentiometry, and copolymer studies. Means to extend the scope of the Critical-Ionization Model to describe and ultimately simulate other steps in the

  18. Modeling of FREYA fast critical experiments with the Serpent Monte Carlo code

    International Nuclear Information System (INIS)

    Fridman, E.; Kochetkov, A.; Krása, A.

    2017-01-01

    Highlights: • FREYA – the EURATOM project executed to support fast lead-based reactor systems. • Critical experiments in the VENUS-F facility during the FREYA project. • Characterization of the critical VENUS-F cores with Serpent. • Comparison of the numerical Serpent results to the experimental data. - Abstract: The FP7 EURATOM project FREYA has been executed between 2011 and 2016 with the aim of supporting the design of fast lead-cooled reactor systems such as MYRRHA and ALFRED. During the project, a number of critical experiments were conducted in the VENUS-F facility located at SCK·CEN, Mol, Belgium. The Monte Carlo code Serpent was one of the codes applied for the characterization of the critical VENUS-F cores. Four critical configurations were modeled with Serpent, namely the reference critical core, the clean MYRRHA mock-up, the full MYRRHA mock-up, and the critical core with the ALFRED island. This paper briefly presents the VENUS-F facility, provides a detailed description of the aforementioned critical VENUS-F cores, and compares the numerical results calculated by Serpent to the available experimental data. The compared parameters include keff, point kinetics parameters, fission rate ratios of important actinides to that of U235 (spectral indices), axial and radial distribution of fission rates, and lead void reactivity effect. The reported results show generally good agreement between the calculated and experimental values. Nevertheless, the paper also reveals some noteworthy issues requiring further attention. This includes the systematic overprediction of reactivity and systematic underestimation of the U238 to U235 fission rate ratio.

  19. Modeling critical zone processes in intensively managed environments

    Science.gov (United States)

    Kumar, Praveen; Le, Phong; Woo, Dong; Yan, Qina

    2017-04-01

    Processes in the Critical Zone (CZ), which sustain terrestrial life, are tightly coupled across hydrological, physical, biochemical, and many other domains over both short and long timescales. In addition, vegetation acclimation resulting from elevated atmospheric CO2 concentration, along with response to increased temperature and altered rainfall pattern, is expected to result in emergent behaviors in ecologic and hydrologic functions, subsequently controlling CZ processes. We hypothesize that the interplay between micro-topographic variability and these emergent behaviors will shape complex responses of a range of ecosystem dynamics within the CZ. Here, we develop a modeling framework ('Dhara') that explicitly incorporates micro-topographic variability based on lidar topographic data with coupling of multi-layer modeling of the soil-vegetation continuum and 3-D surface-subsurface transport processes to study ecological and biogeochemical dynamics. We further couple a C-N model with a physically based hydro-geomorphologic model to quantify (i) how topographic variability controls the spatial distribution of soil moisture, temperature, and biogeochemical processes, and (ii) how farming activities modify the interaction between soil erosion and soil organic carbon (SOC) dynamics. To address the intensive computational demand from high-resolution modeling at lidar data scale, we use a hybrid CPU-GPU parallel computing architecture run over large supercomputing systems for simulations. Our findings indicate that rising CO2 concentration and air temperature have opposing effects on soil moisture, surface water and ponding in topographic depressions. Further, the relatively higher soil moisture and lower soil temperature contribute to decreased soil microbial activities in the low-lying areas due to anaerobic conditions and reduced temperatures. The decreased microbial relevant processes cause the reduction of nitrification rates, resulting in relatively lower nitrate

  20. Designing a model for critical thinking development in AJA University of Medical Sciences

    Science.gov (United States)

    MAFAKHERI LALEH, MAHYAR; MOHAMMADIMEHR, MOJGAN; ZARGAR BALAYE JAME, SANAZ

    2016-01-01

    Introduction: In the new concept of medical education, creativity development is an important goal. The aim of this research was to identify a model for developing critical thinking among students with the special focus on learning environment and learning style. Methods: This applied and cross-sectional study was conducted among all students studying in undergraduate and professional doctorate programs in Fall Semester 2013-2014 in AJA University of Medical Sciences (N=777). The sample consisted of 257 students selected based on the proportional stratified random sampling method. To collect data, three questionnaires including Critical Thinking, Perception of Learning Environment and Learning Style were employed. The data were analyzed using Pearson's correlation statistical test, and one-sample t-test. The Structural Equation Model (SEM) was used to test the research model. SPSS software, version 14 and the LISREL software were used for data analysis. Results: The results showed that students had significantly assessed the teaching-learning environment and two components of "perception of teachers" and "perception of emotional-psychological climate" at the desirable level (pcritical thinking among students in terms of components of "commitment", "creativity" and "cognitive maturity" was at the relatively desirable level (pcritical thinking through learning style. Conclusion: One of the factors which can significantly impact the quality improvement of the teaching and learning process in AJA University of Medical Sciences is to develop critical thinking among learners. This issue requires providing the proper situation for teaching and learning critical thinking in the educational environment. PMID:27795968

  1. Estimating long-term survival of critically ill patients: the PREDICT model.

    Directory of Open Access Journals (Sweden)

    Kwok M Ho

    Full Text Available BACKGROUND: Long-term survival outcome of critically ill patients is important in assessing effectiveness of new treatments and making treatment decisions. We developed a prognostic model for estimation of long-term survival of critically ill patients. METHODOLOGY AND PRINCIPAL FINDINGS: This was a retrospective linked data cohort study involving 11,930 critically ill patients who survived more than 5 days in a university teaching hospital in Western Australia. Older age, male gender, co-morbidities, severe acute illness as measured by Acute Physiology and Chronic Health Evaluation II predicted mortality, and more days of vasopressor or inotropic support, mechanical ventilation, and hemofiltration within the first 5 days of intensive care unit admission were associated with a worse long-term survival up to 15 years after the onset of critical illness. Among these seven pre-selected predictors, age (explained 50% of the variability of the model, hazard ratio [HR] between 80 and 60 years old = 1.95 and co-morbidity (explained 27% of the variability, HR between Charlson co-morbidity index 5 and 0 = 2.15 were the most important determinants. A nomogram based on the pre-selected predictors is provided to allow estimation of the median survival time and also the 1-year, 3-year, 5-year, 10-year, and 15-year survival probabilities for a patient. The discrimination (adjusted c-index = 0.757, 95% confidence interval 0.745-0.769 and calibration of this prognostic model were acceptable. SIGNIFICANCE: Age, gender, co-morbidities, severity of acute illness, and the intensity and duration of intensive care therapy can be used to estimate long-term survival of critically ill patients. Age and co-morbidity are the most important determinants of long-term prognosis of critically ill patients.

  2. The top five research priorities in physician-provided pre-hospital critical care: a consensus report from a European research collaboration

    Directory of Open Access Journals (Sweden)

    Lockey David

    2011-10-01

    Full Text Available Abstract Background Physician-manned emergency medical teams supplement other emergency medical services in some countries. These teams are often selectively deployed to patients who are considered likely to require critical care treatment in the pre-hospital phase. The evidence base for guidelines for pre-hospital triage and immediate medical care is often poor. We used a recognised consensus methodology to define key priority areas for research within the subfield of physician-provided pre-hospital critical care. Methods A European expert panel participated in a consensus process based upon a four-stage modified nominal group technique that included a consensus meeting. Results The expert panel concluded that the five most important areas for further research in the field of physician-based pre-hospital critical care were the following: Appropriate staffing and training in pre-hospital critical care and the effect on outcomes, advanced airway management in pre-hospital care, definition of time windows for key critical interventions which are indicated in the pre-hospital phase of care, the role of pre-hospital ultrasound and dispatch criteria for pre-hospital critical care services. Conclusion A modified nominal group technique was successfully used by a European expert group to reach consensus on the most important research priorities in physician-provided pre-hospital critical care.

  3. The top five research priorities in physician-provided pre-hospital critical care: a consensus report from a European research collaboration

    Science.gov (United States)

    2011-01-01

    Background Physician-manned emergency medical teams supplement other emergency medical services in some countries. These teams are often selectively deployed to patients who are considered likely to require critical care treatment in the pre-hospital phase. The evidence base for guidelines for pre-hospital triage and immediate medical care is often poor. We used a recognised consensus methodology to define key priority areas for research within the subfield of physician-provided pre-hospital critical care. Methods A European expert panel participated in a consensus process based upon a four-stage modified nominal group technique that included a consensus meeting. Results The expert panel concluded that the five most important areas for further research in the field of physician-based pre-hospital critical care were the following: Appropriate staffing and training in pre-hospital critical care and the effect on outcomes, advanced airway management in pre-hospital care, definition of time windows for key critical interventions which are indicated in the pre-hospital phase of care, the role of pre-hospital ultrasound and dispatch criteria for pre-hospital critical care services. Conclusion A modified nominal group technique was successfully used by a European expert group to reach consensus on the most important research priorities in physician-provided pre-hospital critical care. PMID:21996444

  4. A Model Of Critical Peer Feedback To Facilitate Business English Writing Using Qzone Weblogs Among Chinese Undergraduates

    Directory of Open Access Journals (Sweden)

    Gao Xianwei

    2016-10-01

    Full Text Available The purpose of this study was to explore critical thinking skills in peer feedback for Business English writing in order to facilitate the quality of peer feedback and quality of Business English writing. “Critical peer feedback” was conceptualized with the integration of “critical thinking” and “peer feedback” in order to improve the quality of peer feedback. This study explored the process, content and factors of critical peer feedback through Qzone weblogs, and summarized the model of critical peer feedback. A qualitative case study was conducted with a group of six junior students majoring in Business English for one semester in a Chinese university. Three models of critical thinking including Revised Bloom’s Taxonomy, Paul-Elder Model and Reichenbach’s Six Steps Model, were transferred to the participants in the workshops. Three kinds of data including semi-structured interview transcripts, six writing assignments and artifacts of critical peer feedback, were analyzed by QSR NVivo 8. The findings revealed that the Revised Bloom’s Taxonomy is more acceptable for the beginners of critical peer feedback which provides a six-step model of critical thinking. The process of critical peer feedback in online context was summarized as four steps- “intake”, “critical thinking”, “output”, and “post-output”. Each of the four steps had several mental processes in critical peer feedback. This study may be significant for the knowledge of higher-order peer feedback to facilitate the quality of higher-level writing.

  5. Infantile Spasms: A Critical Review of Emerging Animal Models

    Science.gov (United States)

    Stafstrom, Carl E

    2009-01-01

    Infantile spasms is a developmental epilepsy syndrome with unique clinical and EEG features, a specific pattern of pharmacological responsiveness, and poor outcome in terms of cognition and epilepsy. Despite the devastating nature of infantile spasms, little is known about its pathogenesis. Until recently, there has been no animal model available to investigate the pathophysiology of the syndrome or to generate and test novel therapies. Now, several promising animal models have emerged, spanning the etiological spectrum from genetic causes (e.g., Down syndrome or Aristaless-related homeobox [ARX] mutation) to acquired causes (e.g., endogenous and exogenous toxins or stress hormones with convulsant activity or blockade of neural activity). These new models are discussed in this review, with emphasis on the insights each can provide for understanding, treating, and preventing infantile spasms. PMID:19471616

  6. A critical study of quality parameters in health care establishment: developing an integrated quality model.

    Science.gov (United States)

    Azam, Mohammad; Rahman, Zillur; Talib, Faisal; Singh, K J

    2012-01-01

    The purpose of this article is to identify and critically analyze healthcare establishment (HCE) quality parameters described in the literature. It aims to propose an integrated quality model that includes technical quality and associated supportive quality parameters to achieve optimum patient satisfaction. The authors use an extensive in-depth healthcare quality literature review, discerning gaps via a critical analysis in relation to their overall impact on patient management, while identifying an integrated quality model acceptable to hospital staff. The article provides insights into contemporary HCE quality parameters by critically analyzing relevant literature. It also evolves and proposes an integrated HCE-quality model. Owing to HCE confidentiality, especially regarding patient data, information cannot be accessed. The integrated quality model parameters have practical utility for healthcare service managers. However, further studies may be required to refine and integrate newer parameters to ensure continuous quality improvement. This article adds a new perspective to understanding quality parameters and suggests an integrated quality model that has practical value for maintaining HCE service quality to benefit many stakeholders.

  7. Improving Critical Thinking Skills of College Students through RMS Model for Learning Basic Concepts in Science

    Science.gov (United States)

    Muhlisin, Ahmad; Susilo, Herawati; Amin, Mohamad; Rohman, Fatchur

    2016-01-01

    The purposes of this study were to: 1) Examine the effect of RMS learning model towards critical thinking skills. 2) Examine the effect of different academic abilities against critical thinking skills. 3) Examine the effect of the interaction between RMS learning model and different academic abilities against critical thinking skills. The research…

  8. A Critical Analysis of Measurement Models of Export Performance

    Directory of Open Access Journals (Sweden)

    Jorge Carneiro

    2007-05-01

    Full Text Available Poor conceptualization of the export performance construct may undermine theory development efforts and may be one of the reasons behind the often conflicting findings in empirical research on the export performance phenomenon. This article reviews the conceptual and empirical literature and proposes a new analytical scheme that may serve as a standard for judging content validity and a guiding yardstick for drawing operational representations of the construct. A critical assessment of some of the most frequently cited measurement frameworks, followed by an analysis of recent (1999-2004 empirical research, leaves no doubt that there are flaws in the conceptualization and operationalization of the performance construct that ought to be addressed. A new measurement model is advanced along with some guidelines which are suggested for its future empirical validation. The new measurement framework allegedly improves on other past efforts in terms of breadth of coverage of the construct’s domain (content validity. It also offers a measurement perspective (with the simultaneous use of both formative and reflective approaches that appears to reflect better the nature of the construct.

  9. Modelling critical Casimir force induced self-assembly experiments on patchy colloidal dumbbells.

    Science.gov (United States)

    Newton, Arthur C; Nguyen, T Anh; Veen, Sandra J; Kraft, Daniela J; Schall, Peter; Bolhuis, Peter G

    2017-07-19

    Colloidal particles suspended in a binary liquid mixture can interact via solvent mediated interactions, known as critical Casimir forces. For anisotropic colloids this interaction becomes directional, which leads to rich phase behavior. While experimental imaging and particle tracking techniques allow determination of isotropic effective potentials via Boltzmann inversion, the modeling of effective interaction in anisotropic systems is non-trivial precisely because of this directionality. Here we extract effective interaction potentials for non-spherical dumbbell particles from observed radial and angular distributions, by employing reference interaction site model (RISM) theory and direct Monte Carlo simulations. For colloidal dumbbell particles dispersed in a binary liquid mixture and interacting via induced critical Casimir forces, we determine the effective site-site potentials for a range of experimental temperatures. Using these potentials to simulate the system for strong Casimir forces, we reproduce the experimentally observed collapse, and provide a qualitative explanation for this behavior.

  10. Looking through the Critical Lens: The Global Learning Organisation Model

    Science.gov (United States)

    Akella, Devi

    2009-01-01

    This article reconceptualises the meaning of critical theory and its tools of emancipation and critique within the subjective content of cross-cultural literature, globalisation and learning organisation. The first part of the article reviews literature on globalisation and learning companies. The second part discusses the critical approach and…

  11. Managing the complexity of critical infrastructures a modelling and simulation approach

    CERN Document Server

    Rosato, Vittorio; Kyriakides, Elias; Rome, Erich

    2016-01-01

    This book is open access under a CC BY 4.0 license. This book summarizes work being pursued in the context of the CIPRNet (Critical Infrastructure Preparedness and Resilience Research Network) research project, co-funded by the European Union under the Seventh Framework Programme (FP7). The project is intended to provide concrete and on-going support to the Critical Infrastructure Protection (CIP) research communities, enhancing their preparedness for CI-related emergencies, while also providing expertise and technologies for other stakeholders to promote their understanding and mitigation of the consequences of CI disruptions, leading to enhanced resilience. The book collects the tutorial material developed by the authors for several courses on the modelling, simulation and analysis of CIs, representing extensive and integrated CIP expertise. It will help CI stakeholders, CI operators and civil protection authorities understand the complex system of CIs, and help them adapt to these changes and threats in or...

  12. A Grounded Theory Qualitative Analysis of Interprofessional Providers' Perceptions on Caring for Critically Ill Infants and Children in Pediatric and General Emergency Departments.

    Science.gov (United States)

    Gangadharan, Sandeep; Tiyyagura, Gunjan; Gawel, Marcie; Walsh, Barbara M; Brown, Linda L; Lavoie, Megan; Tay, Khoon-Yen; Auerbach, Marc A

    2016-10-04

    The objective of this study was to explore pediatric emergency department (PED) and general emergency department (GED) providers' perceptions on caring for critically ill infants and children. This study utilized qualitative methods to examine the perceptions of emergency department providers caring for critically ill infants and children. Teams of providers participated in 4 in situ simulation cases followed by facilitated debriefings. Debriefings were recorded and professionally transcribed. The transcripts were reviewed independently and followed by group coding discussions to identify emerging themes. Consistent with grounded theory, the team iteratively revised the debriefing script as new understanding was gained. A total of 188 simulation debriefings were recorded in 24 departments, with 15 teams participating from 8 PEDs and 32 teams from 16 GEDs. Twenty-four debriefings were audiotaped and professionally transcribed verbatim. Thematic saturation was achieved after 20 transcripts. In our iterative qualitative analysis of these transcripts, we observed 4 themes: (1) GED provider comfort with algorithm-based pediatric care and overall comfort with pediatric care in PED, (2) GED provider reliance on cognitive aids versus experience-based recall by PED providers, (3) GED provider discomfort with locating and determining size or dose of pediatric-specific equipment and medications, and (4) PED provider reliance on larger team size and challenges with multitasking during resuscitation. Our qualitative analysis produced several themes that help us to understand providers' perceptions in caring for critically ill children in GEDs and PEDs. These data could guide the development of targeted educational and improvement interventions.

  13. An agent-based simulation model of patient choice of health care providers in accountable care organizations.

    Science.gov (United States)

    Alibrahim, Abdullah; Wu, Shinyi

    2018-03-01

    Accountable care organizations (ACO) in the United States show promise in controlling health care costs while preserving patients' choice of providers. Understanding the effects of patient choice is critical in novel payment and delivery models like ACO that depend on continuity of care and accountability. The financial, utilization, and behavioral implications associated with a patient's decision to forego local health care providers for more distant ones to access higher quality care remain unknown. To study this question, we used an agent-based simulation model of a health care market composed of providers able to form ACO serving patients and embedded it in a conditional logit decision model to examine patients capable of choosing their care providers. This simulation focuses on Medicare beneficiaries and their congestive heart failure (CHF) outcomes. We place the patient agents in an ACO delivery system model in which provider agents decide if they remain in an ACO and perform a quality improving CHF disease management intervention. Illustrative results show that allowing patients to choose their providers reduces the yearly payment per CHF patient by $320, reduces mortality rates by 0.12 percentage points and hospitalization rates by 0.44 percentage points, and marginally increases provider participation in ACO. This study demonstrates a model capable of quantifying the effects of patient choice in a theoretical ACO system and provides a potential tool for policymakers to understand implications of patient choice and assess potential policy controls.

  14. Avalanches in self-organized critical neural networks: a minimal model for the neural SOC universality class.

    Directory of Open Access Journals (Sweden)

    Matthias Rybarsch

    Full Text Available The brain keeps its overall dynamics in a corridor of intermediate activity and it has been a long standing question what possible mechanism could achieve this task. Mechanisms from the field of statistical physics have long been suggesting that this homeostasis of brain activity could occur even without a central regulator, via self-organization on the level of neurons and their interactions, alone. Such physical mechanisms from the class of self-organized criticality exhibit characteristic dynamical signatures, similar to seismic activity related to earthquakes. Measurements of cortex rest activity showed first signs of dynamical signatures potentially pointing to self-organized critical dynamics in the brain. Indeed, recent more accurate measurements allowed for a detailed comparison with scaling theory of non-equilibrium critical phenomena, proving the existence of criticality in cortex dynamics. We here compare this new evaluation of cortex activity data to the predictions of the earliest physics spin model of self-organized critical neural networks. We find that the model matches with the recent experimental data and its interpretation in terms of dynamical signatures for criticality in the brain. The combination of signatures for criticality, power law distributions of avalanche sizes and durations, as well as a specific scaling relationship between anomalous exponents, defines a universality class characteristic of the particular critical phenomenon observed in the neural experiments. Thus the model is a candidate for a minimal model of a self-organized critical adaptive network for the universality class of neural criticality. As a prototype model, it provides the background for models that may include more biological details, yet share the same universality class characteristic of the homeostasis of activity in the brain.

  15. Avalanches in self-organized critical neural networks: a minimal model for the neural SOC universality class.

    Science.gov (United States)

    Rybarsch, Matthias; Bornholdt, Stefan

    2014-01-01

    The brain keeps its overall dynamics in a corridor of intermediate activity and it has been a long standing question what possible mechanism could achieve this task. Mechanisms from the field of statistical physics have long been suggesting that this homeostasis of brain activity could occur even without a central regulator, via self-organization on the level of neurons and their interactions, alone. Such physical mechanisms from the class of self-organized criticality exhibit characteristic dynamical signatures, similar to seismic activity related to earthquakes. Measurements of cortex rest activity showed first signs of dynamical signatures potentially pointing to self-organized critical dynamics in the brain. Indeed, recent more accurate measurements allowed for a detailed comparison with scaling theory of non-equilibrium critical phenomena, proving the existence of criticality in cortex dynamics. We here compare this new evaluation of cortex activity data to the predictions of the earliest physics spin model of self-organized critical neural networks. We find that the model matches with the recent experimental data and its interpretation in terms of dynamical signatures for criticality in the brain. The combination of signatures for criticality, power law distributions of avalanche sizes and durations, as well as a specific scaling relationship between anomalous exponents, defines a universality class characteristic of the particular critical phenomenon observed in the neural experiments. Thus the model is a candidate for a minimal model of a self-organized critical adaptive network for the universality class of neural criticality. As a prototype model, it provides the background for models that may include more biological details, yet share the same universality class characteristic of the homeostasis of activity in the brain.

  16. Team Collaboration for Command and Control: A Critical Thinking Model

    National Research Council Canada - National Science Library

    Freeman, Jared T; Serfaty, Daniel

    2002-01-01

    ...: team critical thinking. The framework will be used to understand how team members critique and refine team performance, develop measures of performance, and eventually to create training and decision aids that support...

  17. Critical Path Modeling: University Planning in an Urban Context.

    Science.gov (United States)

    Vasse, William W.; And Others

    1983-01-01

    The experiences of the University of Michigan in developing its Flint campus since the mid-1970s and the use of the Critical Path Method are described. The usefulness of the method during several phases of development is highlighted. (MSE)

  18. Exploring the critical quality attributes and models of smart homes.

    Science.gov (United States)

    Ted Luor, Tainyi; Lu, Hsi-Peng; Yu, Hueiju; Lu, Yinshiu

    2015-12-01

    Research on smart homes has significantly increased in recent years owing to their considerably improved affordability and simplicity. However, the challenge is that people have different needs (or attitudes toward smart homes), and provision should be tailored to individuals. A few studies have classified the functions of smart homes. Therefore, the Kano model is first adopted as a theoretical base to explore whether the functional classifications of smart homes are attractive or necessary, or both. Second, three models and test user attitudes toward three function types of smart homes are proposed. Based on the Kano model, the principal results, namely, two "Attractive Quality" and nine "Indifferent Quality" items, are found. Verification of the hypotheses also indicates that the entertainment, security, and automation functions are significantly correlated with the variables "perceive useful" and "attitude." Cost consideration is negatively correlated with attitudes toward entertainment and automation. Results suggest that smart home providers should survey user needs for their product instead of merely producing smart homes based on the design of the builder or engineer. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  19. Rdh10a Provides a Conserved Critical Step in the Synthesis of Retinoic Acid during Zebrafish Embryogenesis.

    Directory of Open Access Journals (Sweden)

    Enrico D'Aniello

    Full Text Available The first step in the conversion of vitamin A into retinoic acid (RA in embryos requires retinol dehydrogenases (RDHs. Recent studies have demonstrated that RDH10 is a critical core component of the machinery that produces RA in mouse and Xenopus embryos. If the conservation of Rdh10 function in the production of RA extends to teleost embryos has not been investigated. Here, we report that zebrafish Rdh10a deficient embryos have defects consistent with loss of RA signaling, including anteriorization of the nervous system and enlarged hearts with increased cardiomyocyte number. While knockdown of Rdh10a alone produces relatively mild RA deficient phenotypes, Rdh10a can sensitize embryos to RA deficiency and enhance phenotypes observed when Aldh1a2 function is perturbed. Moreover, excess Rdh10a enhances embryonic sensitivity to retinol, which has relatively mild teratogenic effects compared to retinal and RA treatment. Performing Rdh10a regulatory expression analysis, we also demonstrate that a conserved teleost rdh10a enhancer requires Pax2 sites to drive expression in the eyes of transgenic embryos. Altogether, our results demonstrate that Rdh10a has a conserved requirement in the first step of RA production within vertebrate embryos.

  20. A Critical Survey of Optimization Models for Tactical and Strategic Aspects of Air Traffic Flow Management

    Science.gov (United States)

    Bertsimas, Dimitris; Odoni, Amedeo

    1997-01-01

    This document presents a critical review of the principal existing optimization models that have been applied to Air Traffic Flow Management (TFM). Emphasis will be placed on two problems, the Generalized Tactical Flow Management Problem (GTFMP) and the Ground Holding Problem (GHP), as well as on some of their variations. To perform this task, we have carried out an extensive literature review that has covered more than 40 references, most of them very recent. Based on the review of this emerging field our objectives were to: (i) identify the best available models; (ii) describe typical contexts for applications of the models; (iii) provide illustrative model formulations; and (iv) identify the methodologies that can be used to solve the models. We shall begin our presentation below by providing a brief context for the models that we are reviewing. In Section 3 we shall offer a taxonomy and identify four classes of models for review. In Sections 4, 5, and 6 we shall then review, respectively, models for the Single-Airport Ground Holding Problem, the Generalized Tactical FM P and the Multi-Airport Ground Holding Problem (for the definition of these problems see Section 3 below). In each section, we identify the best available models and discuss briefly their computational performance and applications, if any, to date. Section 7 summarizes our conclusions about the state of the art.

  1. An integrated Biophysical CGE model to provide Sustainable Development Goal insights

    Science.gov (United States)

    Sanchez, Marko; Cicowiez, Martin; Howells, Mark; Zepeda, Eduardo

    2016-04-01

    Future projected changes in the energy system will inevitably result in changes to the level of appropriation of environmental resources, particularly land and water, and this will have wider implications for environmental sustainability, and may affect other sectors of the economy. An integrated climate, land, energy and water (CLEW) system will provide useful insights, particularly with regard to the environmental sustainability. However, it will require adequate integration with other tools to detect economic impacts and broaden the scope for policy analysis. A computable general equilibrium (CGE) model is a well suited tool to channel impacts, as detected in a CLEW analysis, onto all sectors of the economy, and evaluate trade-offs and synergies, including those of possible policy responses. This paper will show an application of such integration in a single-country CGE model with the following key characteristics. Climate is partly exogenous (as proxied by temperature and rainfall) and partly endogenous (as proxied by emissions generated by different sectors) and has an impact on endogenous variables such as land productivity and labor productivity. Land is a factor of production used in agricultural and forestry activities which can be of various types if land use alternatives (e.g., deforestation) are to be considered. Energy is an input to the production process of all economic sectors and a consumption good for households. Because it is possible to allow for substitution among different energy sources (e.g. renewable vs non-renewable) in the generation of electricity, the production process of energy products can consider the use of natural resources such as oil and water. Water, data permitting, can be considered as an input into the production process of agricultural sectors, which is particularly relevant in case of irrigation. It can also be considered as a determinant of total factor productivity in hydro-power generation. The integration of a CLEW

  2. A model for facilitation of critical reflective practice

    Directory of Open Access Journals (Sweden)

    TR Mavundla

    2001-09-01

    Full Text Available The impressive growth in the extent and range of psychiatric services provided by general hospitals in South Africa creates stress among nurses employed in these settings who are not psychiatric trained. This manifests itself in negative attitudes displayed towards mentally ill people. The aim of this paper is to discuss the process followed in the development of the model of facilitative communication. A theory generative design was used. The research methods were dealt with in four steps of theory generation as set out below. . Step 1 entailed concept analysis. This step was dealt with in two phases, namely concept identification and concept definition. During concept identification, a qualitative research strategy that is explorative, descriptive and contextual was used. This was achieved through field research conducted in an urban general hospital. A sample of twelve professional nurses was selected from a population of 800 professional nurses employed in a general hospital using the purposive sampling technique. This sample size was determined by saturation of data in themes. Both semi-structured individual phenomenological interviews and observations were used as methods of data collection. Giorgi’s method of descriptive data analysis (1985 was used. Four themes emerged from the results of the study. The main concepts of the model were identified and classified using a survey list of Dickoff et al. (1968. Step 2 dealt with the creation of interrelationship statements between concepts identified in Step 1, while Step 3 dealt with the description of the model using strategies proposed by Chinn and Kramer (1991. In Step 4, the description of guidelines for operationalising in practice was ensured. To ensure valid results, a model for trustworthiness proposed by Guba (Lincoln & Guba, 1985 was used. The following criteria for trustworthiness were applied in all the steps of theory generation: truth value, applicability, consistency and

  3. Elucidating Critical Zone Process Interactions with an Integrated Hydrology Model in a Headwaters Research Catchment

    Science.gov (United States)

    Collins, C.; Maxwell, R. M.

    2017-12-01

    Providence Creek (P300) watershed is an alpine headwaters catchment located at the Southern Sierra Critical Zone Observatory (SSCZO). Evidence of groundwater-dependent vegetation and drought-induced tree mortality at P300 along with the effect of subsurface characterization on mountain ecohydrology motivates this study. A hyper resolution integrated hydrology model of this site, along with extensive instrumentation, provides an opportunity to study the effects of lateral groundwater flow on vegetation's tolerance to drought. ParFlow-CLM is a fully integrated surface-subsurface model that is driven with reconstructed meteorology, such as the North American Land Data Assimilation System project phase 2 (NLDAS-2) dataset. However, large-scale data products mute orographic effects on climate at smaller scales. Climate variables often do not behave uniformly in highly heterogeneous mountain regions. Therefore, forcing physically-based integrated hydrologic models—especially of mountain headwaters catchments—with a large-scale data product is a major challenge. Obtaining reliable observations in complex terrain is challenging and while climate data products introduce uncertainties likewise, documented discrepancies between several data products and P300 observations suggest these data products may suffice. To tackle these issues, a suite of simulations was run to parse out (1) the effects of climate data source (data products versus observations) and (2) the effects of climate data spatial variability. One tool for evaluating the effect of climate data on model outputs is the relationship between latent head flux (LH) and evapotranspiration (ET) partitioning with water table depth (WTD). This zone of LH sensitivity to WTD is referred to as the "critical zone." Preliminary results suggest that these critical zone relationships are preserved despite forcing albeit significant shifts in magnitude. These results demonstrate that integrated hydrology models are sensitive

  4. Work-related critical incidents in hospital-based health care providers and the risk of post-traumatic stress symptoms, anxiety, and depression: a meta-analysis.

    Science.gov (United States)

    de Boer, Jacoba; Lok, Anja; Van't Verlaat, Ellen; Duivenvoorden, Hugo J; Bakker, Arnold B; Smit, Bert J

    2011-07-01

    This meta-analysis reviewed existing data on the impact of work-related critical incidents in hospital-based health care professionals. Work-related critical incidents may induce post-traumatic stress symptoms or even post-traumatic stress disorder (PTSD), anxiety, and depression and may negatively affect health care practitioners' behaviors toward patients. Nurses and doctors often cope by working part time or switching jobs. Hospital administrators and health care practitioners themselves may underestimate the effects of work-related critical incidents. Relevant online databases were searched for original research published from inception to 2009 and manual searches of the Journal of Traumatic Stress, reference lists, and the European Traumatic Stress Research Database were conducted. Two researchers independently decided on inclusion and study quality. Effect sizes were estimated using standardized mean differences with 95% confidence intervals. Consistency was evaluated, using the I(2)-statistic. Meta-analysis was performed using the random effects model. Eleven studies, which included 3866 participants, evaluated the relationship between work-related critical incidents and post-traumatic stress symptoms. Six of these studies, which included 1695 participants, also reported on the relationship between work-related critical incidents and symptoms of anxiety and depression. Heterogeneity among studies was high and could not be accounted for by study quality, character of the incident, or timing of data collection. Pooled effect sizes for the impact of work-related critical incidents on post-traumatic stress symptoms, anxiety, and depression were small to medium. Remarkably, the effect was more pronounced in the longer than in the shorter term. In conclusion, this meta-analysis supports the hypothesis that work-related critical incidents are positively related to post-traumatic stress symptoms, anxiety, and depression in hospital-based health care professionals

  5. A porous flow model for the geometrical form of volcanoes - Critical comments

    Science.gov (United States)

    Wadge, G.; Francis, P.

    1982-01-01

    A critical evaluation is presented of the assumptions on which the mathematical model for the geometrical form of a volcano arising from the flow of magma in a porous medium of Lacey et al. (1981) is based. The lack of evidence for an equipotential surface or its equivalent in volcanoes prior to eruption is pointed out, and the preference of volcanic eruptions for low ground is attributed to the local stress field produced by topographic loading rather than a rising magma table. Other difficulties with the model involve the neglect of the surface flow of lava under gravity away from the vent, and the use of the Dupuit approximation for unconfined flow and the assumption of essentially horizontal magma flow. Comparisons of model predictions with the shapes of actual volcanoes reveal the model not to fit lava shield volcanoes, for which the cone represents the solidification of small lava flows, and to provide a poor fit to composite central volcanoes.

  6. Assessment of Deployment-Related Exposures on Risk of Incident Mental Health Diagnoses Among Air Force Critical Care Providers: Nested Case-Control Study.

    Science.gov (United States)

    Tvaryanas, Anthony P; Maupin, Genny M; Fouts, Brittany L

    2016-02-01

    The purpose of this study was to determine the association between deployment-related occupational/environmental exposures and incident postdeployment mental health (PDMH) conditions in a defined population of military health care professionals working in the deployed critical care environment. A nested case-control study compared cohort members with a PDMH condition (cases, N = 146) with those without a PDMH condition (controls, N = 800) in terms of deployment-related exposures as ascertained using Postdeployment Health Assessment DD 2796 questionnaire data. Multivariable logistic regression models were used to compute odds ratios. Nonphysician career fields (i.e., nurses and medical technicians), exposure to dead bodies or people killed/wounded, history of a vehicular accident/crash, exposure to sand/dust, exposure to lasers, and use of mission-oriented protective posture (MOPP) overgarments were associated with increased likelihood for a PDMH condition. The infrequent exposures (i.e., vehicular accident/crash, lasers, and MOPP overgarments) were the exposures most strongly associated with subsequent PDHM conditions. For military health care providers returning from the deployed environment, several exposures are useful for predicting those at increased risk for a PDMH condition. However, there are likely many other important risk factors beyond those captured on the DD 2796 questionnaire. Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.

  7. Improving Junior High Schools' Critical Thinking Skills Based on Test Three Different Models of Learning

    Science.gov (United States)

    Fuad, Nur Miftahul; Zubaidah, Siti; Mahanal, Susriyati; Suarsini, Endang

    2017-01-01

    The aims of this study were (1) to find out the differences in critical thinking skills among students who were given three different learning models: differentiated science inquiry combined with mind map, differentiated science inquiry model, and conventional model, (2) to find out the differences of critical thinking skills among male and female…

  8. Critical evaluation of paradigms for modelling integrated supply chains

    NARCIS (Netherlands)

    Van Dam, K.H.; Adhitya, A.; Srinivasan, R.; Lukszo, Z.

    2009-01-01

    Contemporary problems in process systems engineering often require model-based decision support tool. Among the various modelling paradigms, equation-based models and agent-based models are widely used to develop dynamic models of systems. Which is the most appropriate modelling paradigm for a

  9. Quantitative Hydraulic Models Of Early Land Plants Provide Insight Into Middle Paleozoic Terrestrial Paleoenvironmental Conditions

    Science.gov (United States)

    Wilson, J. P.; Fischer, W. W.

    2010-12-01

    Fossil plants provide useful proxies of Earth’s climate because plants are closely connected, through physiology and morphology, to the environments in which they lived. Recent advances in quantitative hydraulic models of plant water transport provide new insight into the history of climate by allowing fossils to speak directly to environmental conditions based on preserved internal anatomy. We report results of a quantitative hydraulic model applied to one of the earliest terrestrial plants preserved in three dimensions, the ~396 million-year-old vascular plant Asteroxylon mackei. This model combines equations describing the rate of fluid flow through plant tissues with detailed observations of plant anatomy; this allows quantitative estimates of two critical aspects of plant function. First and foremost, results from these models quantify the supply of water to evaporative surfaces; second, results describe the ability of plant vascular systems to resist tensile damage from extreme environmental events, such as drought or frost. This approach permits quantitative comparisons of functional aspects of Asteroxylon with other extinct and extant plants, informs the quality of plant-based environmental proxies, and provides concrete data that can be input into climate models. Results indicate that despite their small size, water transport cells in Asteroxylon could supply a large volume of water to the plant's leaves--even greater than cells from some later-evolved seed plants. The smallest Asteroxylon tracheids have conductivities exceeding 0.015 m^2 / MPa * s, whereas Paleozoic conifer tracheids do not reach this threshold until they are three times wider. However, this increase in conductivity came at the cost of little to no adaptations for transport safety, placing the plant’s vegetative organs in jeopardy during drought events. Analysis of the thickness-to-span ratio of Asteroxylon’s tracheids suggests that environmental conditions of reduced relative

  10. Critical Thinking and Political Participation: Development and Assessment of a Casual Model.

    Science.gov (United States)

    Guyton, Edith M.

    1988-01-01

    This study assessed a model of the relationship between critical thinking and political participation. Findings indicated that critical thinking has indirect positive effects on orientations toward political participation, that critical thinking positively affects personal control, political efficacy, and democratic attitude, and that personal…

  11. Literature and critical literacy pedagogy in the EFL classroom: Towards a model of teaching critical thinking skills

    Directory of Open Access Journals (Sweden)

    Jelena Bobkina

    2016-12-01

    Full Text Available Drawing on the numerous benefits of integrating literature in the EFL classroom, the present paper argues that the analysis of a fictional work in the process of foreign language acquisition offers a unique opportunity for students to explore, interpret, and understand the world around them. The paper presents strong evidence in favour of reader-centered critical reading as a means of encouraging observation and active evaluation not only of linguistic items, but also of a variety of meanings and viewpoints. The authors propose a model of teaching critical thinking skills focused on the reader’s response to a literary work. The practical application of the method, which adopts the critical literacy approach as a tool, is illustrated through a series of activities based on the poem “If” by Rudyard Kipling.

  12. Neutronic computational modeling of the ASTRA critical facility using MCNPX

    International Nuclear Information System (INIS)

    Rodriguez, L. P.; Garcia, C. R.; Milian, D.; Milian, E. E.; Brayner, C.

    2015-01-01

    The Pebble Bed Very High Temperature Reactor is considered as a prominent candidate among Generation IV nuclear energy systems. Nevertheless the Pebble Bed Very High Temperature Reactor faces an important challenge due to the insufficient validation of computer codes currently available for use in its design and safety analysis. In this paper a detailed IAEA computational benchmark announced by IAEA-TECDOC-1694 in the framework of the Coordinated Research Project 'Evaluation of High Temperature Gas Cooled Reactor (HTGR) Performance' was solved in support of the Generation IV computer codes validation effort using MCNPX ver. 2.6e computational code. In the IAEA-TECDOC-1694 were summarized a set of four calculational benchmark problems performed at the ASTRA critical facility. Benchmark problems include criticality experiments, control rod worth measurements and reactivity measurements. The ASTRA Critical Facility at the Kurchatov Institute in Moscow was used to simulate the neutronic behavior of nuclear pebble bed reactors. (Author)

  13. Self-organized criticality in sandpiles - Nature of the critical phenomenon. [dynamic models in phase transition

    Science.gov (United States)

    Carlson, J. M.; Chayes, J. T.; Swindle, G. H.; Grannan, E. R.

    1990-01-01

    The scaling behavior of sandpile models is investigated analytically. First, it is shown that sandpile models contain a set of domain walls, referred to as troughs, which bound regions that can experience avalanches. It is further shown that the dynamics of the troughs is governed by a simple set of rules involving birth, death, and coalescence events. A simple trough model is then introduced, and it is proved that the model has a phase transition with the density of the troughs as an order parameter and that, in the thermodynamic limit, the trough density goes to zero at the transition point. Finally, it is shown that the observed scaling behavior is a consequence of finite-size effects.

  14. Critical Analysis of the Quality, Readability, and Technical Aspects of Online Information Provided for Neck-Lifts.

    Science.gov (United States)

    Rayess, Hani; Zuliani, Giancarlo F; Gupta, Amar; Svider, Peter F; Folbe, Adam J; Eloy, Jean Anderson; Carron, Michael A

    2017-03-01

    The number of patients using the internet to obtain health information is growing. This material is unregulated and heterogeneous and can influence patient decisions. To compare the quality, readability, and technical aspects of online information about neck-lifts provided by private practice websites vs academic medical centers and reference sources. In this cross-sectional analysis conducted between November 2015 and January 2016, a Google search of the term neck-lift was performed, and the first 45 websites were evaluated. The websites were categorized as private practice vs other. Private websites (PWs) included sites created by private practice physicians. Other websites (OWs) were created by academic medical centers or reference sources. Quality, readability, and technical aspects of online websites related to neck-lifts. Quality was assessed using the DISCERN criteria and the Health on the Net principles (HONcode). Readability was assessed using 7 validated and widely used criteria. Consensus US reading grade level readability was provided by a website (readabilityformulas.com). Twelve technical aspects were evaluated based on criteria specified by medical website creators. Forty-five websites (8 OWs [18%] and 37 PWs [82%]) were analyzed. There was a significant difference in quality between OWs and PWs based on the DISCERN criteria and HONcode principles. The DISCERN overall mean (SD) scores were 2.3 (0.5) for OWs and 1.3 (0.3) for PWs (P analysis, the mean (SD) was 8.6 (1.8) (range, 5-11) for OW, and the mean (SD) was 5.8 (1.7) (range, 2-9) for PW. The mean (SD) readability consensus reading grade level scores were 11.7 (1.9) for OWs and 10.6 (1.9) for PWs. Of a total possible score of 12, the mean (SD) technical scores were 6.3 (1.8) (range, 4-9) for OWs and 6.4 (1.5) (range, 3-9) for PWs. Compared with PWs, OWs had a significantly higher quality score based on both the DISCERN criteria and HONcode principles. The mean readability for OWs and PWs was

  15. Uncertainty modelling of critical column buckling for reinforced ...

    Indian Academy of Sciences (India)

    Buckling is a critical issue for structural stability in structural design. In most of the buckling analyses, applied loads, structural and material properties are considered certain. However, in reality, these parameters are uncertain. Therefore, a prognostic solution is necessary and uncertainties have to be considered. Fuzzy logic ...

  16. Action Learning and Critical Thinking: A Synthesis of Two Models

    Science.gov (United States)

    Soffe, Stephen M.; Marquardt, Michael J.; Hale, Enoch

    2011-01-01

    Recent scholarship and the news media have identified a lack of critical thinking and ethical behavior in the business world. These deficiencies have led to faulty decision-making, ineffective planning, and frequent organizational dysfunction. This situation has focused attention on both practitioners in the field of business and on the university…

  17. Dimers and the Critical Ising Model on lattices of genus >1

    International Nuclear Information System (INIS)

    Costa-Santos, Ruben; McCoy, B.M.

    2002-01-01

    We study the partition function of both Close-Packed Dimers and the Critical Ising Model on a square lattice embedded on a genus two surface. Using numerical and analytical methods we show that the determinants of the Kasteleyn adjacency matrices have a dependence on the boundary conditions that, for large lattice size, can be expressed in terms of genus two theta functions. The period matrix characterizing the continuum limit of the lattice is computed using a discrete holomorphic structure. These results relate in a direct way the lattice combinatorics with conformal field theory, providing new insight to the lattice regularization of conformal field theories on higher genus Riemann surfaces

  18. Salinity critical threshold values for photosynthesis of two cosmopolitan seaweed species: providing baselines for potential shifts on seaweed assemblages.

    Science.gov (United States)

    Scherner, Fernando; Ventura, Robson; Barufi, José Bonomi; Horta, Paulo Antunes

    2013-10-01

    Climate change has increased precipitation in several South American regions leading to higher freshwater inputs into marine systems with potential to cause salinity declines along the coast. The current salinity profile on the southern coast of Brazil was surveyed during four years providing a baseline of the current salinity pattern in the region. Additionally, the effects of salinity decreases on the photosynthesis of the seaweeds Ulva lactuca and Sargassum stenophyllum were investigated in laboratory. Seaweeds were cultured at salinities 5, 15 and 34 and at the mean winter and summer temperatures. Photosynthetic performance was measured following 24 and 96 h from the beginning of experiment. U. lactuca remained practically unaltered by low salinities while S. stenophyllum presented declines of important photosynthetic parameters. This is due to the different regulation abilities of energy distribution at the PSII of the two species. These differences have potential to lead to seaweed community shifts. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. m-Health: A Critical Analysis of Awareness, Perception, and Attitude of Healthcare Among Providers in Himachal Pradesh, North India.

    Science.gov (United States)

    Ganapathy, Krishnan; Kanwar, Vikrant; Bhatnagar, Tarun; Uthayakumaran, N

    2016-08-01

    Providing healthcare in remote mountainous areas is challenging. The increasing availability of mobile connectivity needs to be exploited by offering healthcare through a mobile medium, popularly known as mobile health (m-health). It is essential to understand the awareness, perception, and attitude of healthcare providers (HCPs) in deploying m-health. Their outlook on new technologies influences patient adoption. Reports on attitudes regarding healthcare through mobile phones are now confined to views from the recipient. This study from August 1 to September 30, 2014 analyzed the views of 592 HCPs (12.3% of all HCPs) in Himachal Pradesh, India. They included faculty and students of the two medical colleges, as well as HCPs from all of the 12 districts. Although Himachal Pradesh has the highest teledensity of all states in India (117.6%), only 58.8% of HCPs (of those surveyed, 72% lived in suburban areas and 24.8% in Shimla, the state capital) would easily recommend m-health. Self-perceived ability to use mobile services was 85%. Fifty-nine percent used mobile devices for social networking, and 52.4% used Wi-Fi. Sixty-one percent of those interviewed were females, and 39% were males. The transformative potential of m-health hinges on its acceptance and use by all stakeholders. The study suggests that as HCPs in Himachal Pradesh are already using mobile value added services and are highly information technology literate, addressing their specific concerns could lead to use of m-health in Himachal Pradesh. Healthcare delivery in Himachal Pradesh is still suboptimal. With increasing connectivity, awareness, and commencement of telemedicine services in Himachal Pradesh, m-health has the potential to be a reality.

  20. Critical review of activated sludge modeling: state of process knowledge, modeling concepts, and limitations.

    Science.gov (United States)

    Hauduc, H; Rieger, L; Oehmen, A; van Loosdrecht, M C M; Comeau, Y; Héduit, A; Vanrolleghem, P A; Gillot, S

    2013-01-01

    This work critically reviews modeling concepts for standard activated sludge wastewater treatment processes (e.g., hydrolysis, growth and decay of organisms, etc.) for some of the most commonly used models. Based on a short overview on the theoretical biochemistry knowledge this review should help model users to better understand (i) the model concepts used; (ii) the differences between models, and (iii) the limits of the models. The seven analyzed models are: (1) ASM1; (2) ASM2d; (3) ASM3; (4) ASM3 + BioP; (5) ASM2d + TUD; (6) Barker & Dold model; and (7) UCTPHO+. Nine standard processes are distinguished and discussed in the present work: hydrolysis; fermentation; ordinary heterotrophic organisms (OHO) growth; autotrophic nitrifying organisms (ANO) growth; OHO & ANO decay; poly-hydroxyalkanoates (PHA) storage; polyphosphate (polyP) storage; phosphorus accumulating organisms PAO) growth; and PAO decay. For a structured comparison, a new schematic representation of these processes is proposed. Each process is represented as a reaction with consumed components on the left of the figure and produced components on the right. Standardized icons, based on shapes and color codes, enable the representation of the stoichiometric modeling concepts and kinetics. This representation allows highlighting the conceptual differences of the models, and the level of simplification between the concepts and the theoretical knowledge. The model selection depending on their theoretical limitations and the main research needs to increase the model quality are finally discussed. Copyright © 2012 Wiley Periodicals, Inc.

  1. Uncertainty analysis on simple mass balance model to calculate critical loads for soil acidity

    International Nuclear Information System (INIS)

    Li Harbin; McNulty, Steven G.

    2007-01-01

    Simple mass balance equations (SMBE) of critical acid loads (CAL) in forest soil were developed to assess potential risks of air pollutants to ecosystems. However, to apply SMBE reliably at large scales, SMBE must be tested for adequacy and uncertainty. Our goal was to provide a detailed analysis of uncertainty in SMBE so that sound strategies for scaling up CAL estimates to the national scale could be developed. Specifically, we wanted to quantify CAL uncertainty under natural variability in 17 model parameters, and determine their relative contributions in predicting CAL. Results indicated that uncertainty in CAL came primarily from components of base cation weathering (BC w ; 49%) and acid neutralizing capacity (46%), whereas the most critical parameters were BC w base rate (62%), soil depth (20%), and soil temperature (11%). Thus, improvements in estimates of these factors are crucial to reducing uncertainty and successfully scaling up SMBE for national assessments of CAL. - A comprehensive uncertainty analysis, with advanced techniques and full list and full value ranges of all individual parameters, was used to examine a simple mass balance model and address questions of error partition and uncertainty reduction in critical acid load estimates that were not fully answered by previous studies

  2. Firm Deadline Checking of Safety-Critical Java Applications with Statistical Model Checking

    DEFF Research Database (Denmark)

    Ravn, Anders P.; Thomsen, Bent; Søe Luckow, Kasper

    2017-01-01

    In cyber-physical applications many programs have hard real-time constraints that have to be stringently validated. In some applications, there are programs that have hard deadlines, which must not be violated. Other programs have soft deadlines where the value of the response decreases when...... hard deadline constraints to the case of firm deadlines for application programs written in Safety-Critical Java (SCJ). The existing approach uses models and model checking with the Uppaal toolset; the extension uses the statistical model checking features of Uppaal-smc to provide a hold on firm...... deadlines and performance in the case of soft deadlines. The extended approach is illustrated with examples from applications....

  3. THE EFFECT OF LEARNING MODELS ON BIOLOGY CRITICAL THINKING SKILLS OF MULTIETHNIC STUDENTS AT SENIOR HIGH SCHOOLS IN INDONESIA

    Directory of Open Access Journals (Sweden)

    Didimus Tanah Boleng

    2017-04-01

    Full Text Available Teachers play an important role in the world of education, including in the process of planning the learning activities. A meaningful learning will be able to provide a good effect on students’ thinking ability. One of the students’ thinking skills that can be empowered is the critical thinking. Critical thinking skills can help a person to face the challenges of a globalized world. This research aimed at revealing the effect of PBL learning model on the critical thinking skills of multiethnic students. The design of this research was quasi experimental in non-equivalent pretest-posttest control group design. This research was conducted on multiethnic students of class XI Science in July-December 2016, in Samarinda, Indonesia. The results of the data analysis showed that learning model had an effect on students’ critical thinking skills. PBL model had a mean score of students’ critical thinking skill 73.81% higher than that of the conventional learning. Ethnics had an effect on students' critical thinking skills. The mean score of students’ critical thinking skills of Javanese was 11.94% higher than that of the Kutai ethnic, and 13.17% higher than that of the Banjar ethnic.

  4. THE EFFECTS OF INQUIRY LEARNING MODEL TRAINING AND CRITICAL THINKING TOWARDS SMA STUDENT LEARNING OUTCOMES

    Directory of Open Access Journals (Sweden)

    Ella Lady Saura

    2014-12-01

    Full Text Available The purposes of the research are: (1 To determine differences in learning outcomes of students with Inquiry Training models and Direct Instruction teaching models, (2 to determine differences in physics learning outcomes of students who have high critical thinking and low critical thinking, (3 to determine the interaction between learning models with the level of critical thinking in improving student Physics learning outcomes. The sample in this study conducted in a cluster random sampling of two classes, where the first class as a class experiment applied Inquiry Training models as a class and the second class of controls implemented Direct Instruction models. The instrument is used in this study is physics learning outcomes tests in narrative form as many as 7 questions and critical thinking test in narrative form as 7 questions that have been declared valid and reliable. The results were found: (1 there are differences in physical students learning outcomes are taught by Inquiry Training models and Direct Instruction teaching models. Learning outcomes of students who are taught by Inquiry Learning Model Training better than student learning outcomes are taught with Direct Instruction Model Learning. (2 There is a difference in student's learning outcomes that have high critical thinking and low critical thinking. Student learning outcomes that have a high critical thinking better than student learning outcomes that have a low critical thinking. (3 There is interaction between learning and mastery of material Model Physics prerequisite to student learning outcomes. Learning outcomes of students who are taught by the model is influenced also by the Inquiry Training critical thinking, while learning outcomes of students who are taught with Direct Instruction models are not affected by the students' critical thinking.

  5. Towards a dynamic assessment of raw materials criticality: Linking agent-based demand — With material flow supply modelling approaches

    International Nuclear Information System (INIS)

    Knoeri, Christof; Wäger, Patrick A.; Stamp, Anna; Althaus, Hans-Joerg; Weil, Marcel

    2013-01-01

    Emerging technologies such as information and communication-, photovoltaic- or battery technologies are expected to increase significantly the demand for scarce metals in the near future. The recently developed methods to evaluate the criticality of mineral raw materials typically provide a ‘snapshot’ of the criticality of a certain material at one point in time by using static indicators both for supply risk and for the impacts of supply restrictions. While allowing for insights into the mechanisms behind the criticality of raw materials, these methods cannot account for dynamic changes in products and/or activities over time. In this paper we propose a conceptual framework intended to overcome these limitations by including the dynamic interactions between different possible demand and supply configurations. The framework integrates an agent-based behaviour model, where demand emerges from individual agent decisions and interaction, into a dynamic material flow model, representing the materials' stocks and flows. Within the framework, the environmental implications of substitution decisions are evaluated by applying life-cycle assessment methodology. The approach makes a first step towards a dynamic criticality assessment and will enhance the understanding of industrial substitution decisions and environmental implications related to critical metals. We discuss the potential and limitation of such an approach in contrast to state-of-the-art methods and how it might lead to criticality assessments tailored to the specific circumstances of single industrial sectors or individual companies. - Highlights: ► Current criticality assessment methods provide a ‘snapshot’ at one point in time. ► They do not account for dynamic interactions between demand and supply. ► We propose a conceptual framework to overcomes these limitations. ► The framework integrates an agent-based behaviour model with a dynamic material flow model. ► The approach proposed makes

  6. Identification and Control of Aircrafts using Multiple Models and Adaptive Critics

    Science.gov (United States)

    Principe, Jose C.

    2007-01-01

    We compared two possible implementations of local linear models for control: one approach is based on a self-organizing map (SOM) to cluster the dynamics followed by a set of linear models operating at each cluster. Therefore the gating function is hard (a single local model will represent the regional dynamics). This simplifies the controller design since there is a one to one mapping between controllers and local models. The second approach uses a soft gate using a probabilistic framework based on a Gaussian Mixture Model (also called a dynamic mixture of experts). In this approach several models may be active at a given time, we can expect a smaller number of models, but the controller design is more involved, with potentially better noise rejection characteristics. Our experiments showed that the SOM provides overall best performance in high SNRs, but the performance degrades faster than with the GMM for the same noise conditions. The SOM approach required about an order of magnitude more models than the GMM, so in terms of implementation cost, the GMM is preferable. The design of the SOM is straight forward, while the design of the GMM controllers, although still reasonable, is more involved and needs more care in the selection of the parameters. Either one of these locally linear approaches outperform global nonlinear controllers based on neural networks, such as the time delay neural network (TDNN). Therefore, in essence the local model approach warrants practical implementations. In order to call the attention of the control community for this design methodology we extended successfully the multiple model approach to PID controllers (still today the most widely used control scheme in the industry), and wrote a paper on this subject. The echo state network (ESN) is a recurrent neural network with the special characteristics that only the output parameters are trained. The recurrent connections are preset according to the problem domain and are fixed. In a

  7. Critical properties of a simple spin glass model

    International Nuclear Information System (INIS)

    Aharony, A.; Imry, Y.

    1976-01-01

    The Mattis spin glass model is described as following from a particular quenched random solid solution picture, and its zero-field properties are discussed. The random field model is reviewed. The application to the spin glass problem is made and the more general scaling theory presented, and the limitations of the model are discussed

  8. Developing graduate student competency in providing culturally sensitive end of life care in critical care environments - a pilot study of a teaching innovation.

    Science.gov (United States)

    Northam, Holly L; Hercelinskyj, Gylo; Grealish, Laurie; Mak, Anita S

    2015-11-01

    Australia's immigration policy has generated a rich diverse cultural community of staff and patients in critical care environments. Many different cultural perspectives inform individual actions in the context of critical care, including the highly sensitive area of end of life care, with nurses feeling poorly prepared to provide culturally sensitive end of life care. This article describes and evaluates the effectiveness of an educational innovation designed to develop graduate-level critical care nurses' capacity for effective interpersonal communication, as members of a multi-disciplinary team in providing culturally sensitive end-of-life care. A mixed method pilot study was conducted using a curriculum innovation intervention informed by The Excellence in Cultural Experiential Learning and Leadership Program (EXCELL),(1) which is a higher education intervention which was applied to develop the nurses' intercultural communication skills. 12 graduate nursing students studying critical care nursing participated in the study. 42% (n=5) of the participants were from an international background. Information about students' cultural learning was recorded before and after the intervention, using a cultural learning development scale. Student discussions of end of life care were recorded at Week 2 and 14 of the curriculum. The quantitative data was analysed using descriptive statistical analysis and qualitative data was thematically analysed. Students demonstrated an increase in cultural learning in a range of areas in the pre-post surveys including understandings of cultural diversity, interpersonal skills, cross cultural interactions and participating in multicultural groups. Thematic analysis of the end of life discussions revealed an increase in the levels of nurse confidence in approaching end of life care in critical care environments. The EXCELL program provides an effective and supportive educational framework to increase graduate nurses' cultural learning

  9. Critical Infrastructure Interdependency Modeling: A Survey of U.S. and International Research

    Energy Technology Data Exchange (ETDEWEB)

    2006-08-01

    The Nation’s health, wealth, and security rely on the production and distribution of certain goods and services. The array of physical assets, processes, and organizations across which these goods and services move are called "critical infrastructures".1 This statement is as true in the U.S. as in any country in the world. Recent world events such as the 9-11 terrorist attacks, London bombings, and gulf coast hurricanes have highlighted the importance of stable electric, gas and oil, water, transportation, banking and finance, and control and communication infrastructure systems. Be it through direct connectivity, policies and procedures, or geospatial proximity, most critical infrastructure systems interact. These interactions often create complex relationships, dependencies, and interdependencies that cross infrastructure boundaries. The modeling and analysis of interdependencies between critical infrastructure elements is a relatively new and very important field of study. The U.S. Technical Support Working Group (TSWG) has sponsored this survey to identify and describe this current area of research including the current activities in this field being conducted both in the U.S. and internationally. The main objective of this study is to develop a single source reference of critical infrastructure interdependency modeling tools (CIIMT) that could be applied to allow users to objectively assess the capabilities of CIIMT. This information will provide guidance for directing research and development to address the gaps in development. The results will inform researchers of the TSWG Infrastructure Protection Subgroup of research and development efforts and allow a more focused approach to addressing the needs of CIIMT end-user needs. This report first presents the field of infrastructure interdependency analysis, describes the survey methodology, and presents the leading research efforts in both a cumulative table and through individual datasheets. Data was

  10. Z(4) model: criticality and break-collapse method

    International Nuclear Information System (INIS)

    Mariz, A.M.; Tsallis, C.; Fulco, P.

    1985-01-01

    Within a real-space renormalization group (RG) framework, the criticality of the Z(4) ferromagnet on square lattice is studied. The phase diagram (exhibiting ferromagnetic, paramagnetic and nematic-like phases) recovers all the available exact results, and possibly is a high precision one everywhere. In particular the main asymptotic behaviours (bifurcation and Ising regions) are established. In addition to that, an operational procedure is developed (Break-collapse method) which considerably simplifies the exact calculation of arbitrary Z(4) two-terminal clusters (commonly appearing in RG approaches). (Author) [pt

  11. A critical review of the data requirements for fluid flow models through fractured rock

    International Nuclear Information System (INIS)

    Priest, S.D.

    1986-01-01

    The report is a comprehensive critical review of the data requirements for ten models of fluid flow through fractured rock, developed in Europe and North America. The first part of the report contains a detailed review of rock discontinuities and how their important geometrical properties can be quantified. This is followed by a brief summary of the fundamental principles in the analysis of fluid flow through two-dimensional discontinuity networks and an explanation of a new approach to the incorporation of variability and uncertainty into geotechnical models. The report also contains a review of the geological and geotechnical properties of anhydrite and granite. Of the ten fluid flow models reviewed, only three offer a realistic fracture network model for which it is feasible to obtain the input data. Although some of the other models have some valuable or novel features, there is a tendency to concentrate on the simulation of contaminant transport processes, at the expense of providing a realistic fracture network model. Only two of the models reviewed, neither of them developed in Europe, have seriously addressed the problem of analysing fluid flow in three-dimensional networks. (author)

  12. Criticality of O (N ) symmetric models in the presence of discrete gauge symmetries

    Science.gov (United States)

    Pelissetto, Andrea; Tripodo, Antonio; Vicari, Ettore

    2018-01-01

    We investigate the critical properties of the three-dimensional antiferromagnetic RPN -1 model, which is characterized by a global O (N ) symmetry and a discrete Z2 gauge symmetry. We perform a field-theoretical analysis using the Landau-Ginzburg-Wilson (LGW) approach and a numerical Monte Carlo study. The LGW field-theoretical results are obtained by high-order perturbative analyses of the renormalization-group flow of the most general Φ4 theory with the same global symmetry as the model, assuming a gauge-invariant order-parameter field. For N =4 no stable fixed point is found, implying that any transition must necessarily be of first order. This is contradicted by the numerical results that provide strong evidence for a continuous transition. This suggests that gauge modes are not always irrelevant, as assumed by the LGW approach, but they may play an important role to determine the actual critical dynamics at the phase transition of O (N ) symmetric models with a discrete Z2 gauge symmetry.

  13. The Revised Hierarchical Model: A critical review and assessment

    OpenAIRE

    Kroll, Judith F.; van Hell, Janet G.; Tokowicz, Natasha; Green, David W.

    2010-01-01

    Brysbaert and Duyck (2009) suggest that it is time to abandon the Revised Hierarchical Model (Kroll and Stewart, 1994) in favor of connectionist models such as BIA+ (Dijkstra and Van Heuven, 2002) that more accurately account for the recent evidence on nonselective access in bilingual word recognition. In this brief response, we first review the history of the Revised Hierarchical Model (RHM), consider the set of issues that it was proposed to address, and then evaluate the evidence that supp...

  14. Criticism of the Classical Theory of Macroeconomic Modeling

    Directory of Open Access Journals (Sweden)

    Konstantin K. Kumehov

    2015-01-01

    Full Text Available Abstract: Current approaches and methods of modeling of macroeconomic systems do not allow to generate research ideas that could be used in applications. This is largely due to the fact that the dominant economic schools and research directions are building their theories on misconceptions about the economic system as object modeling, and have no common methodological approaches in the design of macroeconomic models. All of them are focused on building a model aimed at establishing equilibrium parameters of supply and demand, production and consumption. At the same time as the underlying factors are not considered resource potential and the needs of society in material and other benefits. In addition, there is no unity in the choice of elements and mechanisms of interaction between them. Not installed, what are the criteria to determine the elements of the model: whether it is the institutions, whether the industry is whether the population, or banks, or classes, etc. From the methodological point of view, the design of the model all the most well-known authors extrapolated to the new models of the past state or past events. As a result, every time the model is ready by the time the situation changes, the last parameters underlying the model are losing relevance, so at best, the researcher may have to interpret the events and parameters that are not feasible in the future. In this paper, based on analysis of the works of famous authors, belonging to different schools and areas revealed weaknesses of their proposed macroeconomic models that do not allow you to use them to solve applied problems of economic development. A fundamentally new approaches and methods by which it is possible the construction of macroeconomic models that take into account the theoretical and applied aspects of modeling, as well as formulated the basic methodological requirements.

  15. A parametric model for the global thermodynamic behavior of fluids in the critical region

    International Nuclear Information System (INIS)

    Luettmer-Strathmann, J.; Tang, S.; Sengers, J.V.

    1992-01-01

    The asymptotic thermodynamic behavior of fluids near the critical point is described by scaling laws with universal scaling functions that can be represented by parametric equations. In this paper, we derive a more general parametric model that incorporates the crossover from singular thermodynamic behavior near the critical point to regular classical thermodynamic behavior far away from the critical point. Using ethane as an example, we show that such a parametric crossover model yields an accurate representation of the thermodynamic properties of fluids in a large region around the critical point

  16. Providing or designing? Constructing models in primary maths education (IF. 0.756)

    NARCIS (Netherlands)

    van Dijk, I.M.A.W.; van Oers, H.J.M.; Terwel, J.

    2003-01-01

    The goal of this exploratory study was to uncover the construction processes which occur when pupils are taught to work with models in primary maths education. Two approaches were studied: 'providing models' versus 'designing models in co-construction'. A qualitative observational study involved two

  17. The Revised Hierarchical Model: A critical review and assessment

    NARCIS (Netherlands)

    Kroll, J.F.; Hell, J.G. van; Tokowicz, N.; Green, D.W.

    2010-01-01

    Brysbaert and Duyck (this issue) suggest that it is time to abandon the Revised Hierarchical Model (Kroll and Stewart, 1994) in favor of connectionist models such as BIA+ (Dijkstra and Van Heuven, 2002) that more accurately account for the recent evidence on non-selective access in bilingual word

  18. Models of alcoholic liver disease in rodents: a critical evaluation

    DEFF Research Database (Denmark)

    de la M. Hall, P.; Lieber, C.S.; De Carli, L.M.

    2001-01-01

    ) Lieber-DeCarli liquid diet for alcohol-induced liver injury in rats, by C. S. Lieber and L. M. DeCarli; (3) Tsukamoto-French model of alcoholic liver injury, by S. W. French; (4) Animal models to study endotoxin-ethanol interactions, by K. O. Lindros and H. Järveläinen; and (5) Jejunoileal bypass...

  19. Critical Correlation Functions for the 4-Dimensional Weakly Self-Avoiding Walk and n-Component {|\\varphi|^4} Model

    Science.gov (United States)

    Slade, Gordon; Tomberg, Alexandre

    2016-03-01

    We extend and apply a rigorous renormalisation group method to study critical correlation functions, on the 4-dimensional lattice Z4, for the weakly coupled n-component {|\\varphi|4} spin model for all {n ≥ 1}, and for the continuous-time weakly self-avoiding walk. For the {|\\varphi|4} model, we prove that the critical two-point function has | x|-2 (Gaussian) decay asymptotically, for {n ≥ 1}. We also determine the asymptotic decay of the critical correlations of the squares of components of {\\varphi}, including the logarithmic corrections to Gaussian scaling, for {n ≥ 1}. The above extends previously known results for n = 1 to all {n ≥ 1}, and also observes new phenomena for n > 1, all with a new method of proof. For the continuous-time weakly self-avoiding walk, we determine the decay of the critical generating function for the "watermelon" network consisting of p weakly mutually- and self-avoiding walks, for all {p ≥ 1}, including the logarithmic corrections. This extends a previously known result for p = 1, for which there is no logarithmic correction, to a much more general setting. In addition, for both models, we study the approach to the critical point and prove the existence of logarithmic corrections to scaling for certain correlation functions. Our method gives a rigorous analysis of the weakly self-avoiding walk as the n = 0 case of the {|\\varphi|4} model, and provides a unified treatment of both models, and of all the above results.

  20. Modelling the exposure induced by a criticality excursion in solution

    International Nuclear Information System (INIS)

    Kerouanton, David; Delgovea, Laure; Castaniera, Eric; Raimondia, Nicolas

    2008-01-01

    During a criticality accident, significant exposure is generated by 4 radiation origins: radiation directly induced by fissions (prompt neutrons and gamma), gamma radiations induced by (n, γ) reactions in crossed materials (capture gamma) and gamma radiations emitted by fission products. Due to boiling of the solution, a fraction of fissions products is airborne and is deposited in the ventilation shafts. 5.10 18 fissions are considered in a dissolution tank containing uranyl nitrate by using the deterministic ATTILA radiation transport code. Instantaneous radiations rates are evaluated as a function of the distance and compared with data available in the literature. Dose rates induced behind various shielding materials such as concrete, steel or glass are assessed. In all cases, relative contributions of prompt or capture radiations is detailed. (author)

  1. Self-organized critical model for protein folding

    Science.gov (United States)

    Moret, M. A.

    2011-09-01

    The major factor that drives a protein toward collapse and folding is the hydrophobic effect. At the folding process a hydrophobic core is shielded by the solvent-accessible surface area of the protein. We study the fractal behavior of 5526 protein structures present in the Brookhaven Protein Data Bank. Power laws of protein mass, volume and solvent-accessible surface area are measured independently. The present findings indicate that self-organized criticality is an alternative explanation for the protein folding. Also we note that the protein packing is an independent and constant value because the self-similar behavior of the volumes and protein masses have the same fractal dimension. This power law guarantees that a protein is a complex system. From the analyzed data, q-Gaussian distributions seem to fit well this class of systems.

  2. Uncertainty quantification of RELAP5/MOD3/KAERI critical flow model using Marviken experimental data

    International Nuclear Information System (INIS)

    Lee, Sang Yong; Kwon, Tae Soon; Lee, Won Jae; Lee, Young Jin

    1994-06-01

    The uncertainty in the critical flow model of RELAP5/MOD3 is quantified by the direct comparison to the experimental data. The realistic critical flow discharge coefficients and associated uncertainties are determined for the subcooled critical flow and two-phase critical flow by assessment of nine-MARVIKEN critical flow tests(CFT). The realistic discharge coefficients are determined to be 0.89 for the subcooled critical flow and 1.07 for the two-phase critical flow, and the associated standard deviations are 0.03491 and 0.1189, respectively. The results obtained from this study can be applied to the calculation of the realistic response of LBLOCA (Large Break Loss of Coolant Accident) scenario and to evaluate the realistic ECCS (Emergency Core Cooling System) performance. (Author) 8 refs., 15 figs., 3 tabs

  3. Working Group 2: A critical appraisal of model simulations

    International Nuclear Information System (INIS)

    MacCracken, M.; Cubasch, U.; Gates, W.L.; Harvey, L.D.; Hunt, B.; Katz, R.; Lorenz, E.; Manabe, S.; McAvaney, B.; McFarlane, N.; Meehl, G.; Meleshko, V.; Robock, A.; Stenchikov, G.; Stouffer, R.; Wang, W.C.; Washington, W.; Watts, R.; Zebiak, S.

    1990-01-01

    The complexity of the climate system and the absence of definitive analogs to the evolving climatic situation force use of theoretical models to project the future climatic influence of the relatively rapid and on-going increase in the atmospheric concentrations of CO 2 and other trace gases. A wide variety of climate models has been developed to look at particular aspects of the problem and to vary the mix of complexity and resource requirements needed to study various aspects of the problem; all such models have contributed to their insights of the problem

  4. Improving Junior High Schools’ Critical Thinking Skills Based on Test Three Different Models of Learning

    OpenAIRE

    Nur Miftahul Fuad; Siti Zubaidah; Susriyati Mahanal; Endang Suarsini

    2017-01-01

    The aims of this study were (1) to find out the differences in critical thinking skills among students who were given three different learning models: differentiated science inquiry combined with mind map, differentiated science inquiry model, and conventional model, (2) to find out the differences of critical thinking skills among male and female students. This study is a quasi-experimental research with pretest-posttest nonequivalent control group design. The population in...

  5. Thermodynamically consistent description of criticality in models of correlated electrons

    Czech Academy of Sciences Publication Activity Database

    Janiš, Václav; Kauch, Anna; Pokorný, Vladislav

    2017-01-01

    Roč. 95, č. 4 (2017), s. 1-14, č. článku 045108. ISSN 2469-9950 R&D Projects: GA ČR GA15-14259S Institutional support: RVO:68378271 Keywords : conserving approximations * Anderson model * Hubbard model * parquet equations Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.836, year: 2016

  6. Structural identifiability of systems biology models: a critical comparison of methods.

    Directory of Open Access Journals (Sweden)

    Oana-Teodora Chis

    Full Text Available Analysing the properties of a biological system through in silico experimentation requires a satisfactory mathematical representation of the system including accurate values of the model parameters. Fortunately, modern experimental techniques allow obtaining time-series data of appropriate quality which may then be used to estimate unknown parameters. However, in many cases, a subset of those parameters may not be uniquely estimated, independently of the experimental data available or the numerical techniques used for estimation. This lack of identifiability is related to the structure of the model, i.e. the system dynamics plus the observation function. Despite the interest in knowing a priori whether there is any chance of uniquely estimating all model unknown parameters, the structural identifiability analysis for general non-linear dynamic models is still an open question. There is no method amenable to every model, thus at some point we have to face the selection of one of the possibilities. This work presents a critical comparison of the currently available techniques. To this end, we perform the structural identifiability analysis of a collection of biological models. The results reveal that the generating series approach, in combination with identifiability tableaus, offers the most advantageous compromise among range of applicability, computational complexity and information provided.

  7. Model of facilitation of emotional intelligence to promote wholeness of neophyte critical care nurses in South Africa

    Directory of Open Access Journals (Sweden)

    A. Towell

    2015-10-01

    Full Text Available This study was undertaken in order to develop a model of facilitation of emotional intelligence to promote wholeness in neophyte critical care nurses in South Africa. A theory generative, explorative, descriptive, contextual research design was used. The model was developed utilising the four steps of theory generation as proposed by Dickoff, James, and Wiedenbach (1968, Chinn and Kramer (2011 and Walker and Avant (2011. Step one dealt with the empirical phase in which the concepts were distilled. The facilitation of inherent affective and mental resourcefulness and resilience was the main concept of the model. Step two comprised the definition and classification of central and related concepts. Step three provides a description of the model. The model operates in three phases namely the dependent phase, partially dependent phase and the independent phase. Step four entailed the description of guidelines for operationalizing the model. During the three phases of the model a new nurse who starts to work in critical care moves from a latent ability to develop an inherent affective and mental resourcefulness and resilience to a state of developing an inherent affective and mental resourcefulness and resilience. This model provides a structured framework for the facilitation of emotional intelligence (EI to promote wholeness in nurses who commence to work in critical care units.

  8. New Provider Models for Sweden and Spain: Public, Private or Non-profit? Comment on "Governance, Government, and the Search for New Provider Models".

    Science.gov (United States)

    Jeurissen, Patrick P T; Maarse, Hans

    2016-06-29

    Sweden and Spain experiment with different provider models to reform healthcare provision. Both models have in common that they extend the role of the for-profit sector in healthcare. As the analysis of Saltman and Duran demonstrates, privatisation is an ambiguous and contested strategy that is used for quite different purposes. In our comment, we emphasize that their analysis leaves questions open on the consequences of privatisation for the performance of healthcare and the role of the public sector in healthcare provision. Furthermore, we briefly address the absence of the option of healthcare provision by not-for-profit providers in the privatisation strategy of Sweden and Spain. © 2016 The Author(s); Published by Kerman University of Medical Sciences. This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

  9. EFFECT OF PROBLEM BASED LEARNING AND MODEL CRITICAL THINKING ABILITY TO PROBLEM SOLVING SKILLS

    Directory of Open Access Journals (Sweden)

    Unita S. Zuliani Nasution

    2016-12-01

    Full Text Available The purposes of this research were to analyze the different between physic resolving problem ability by using problem based learning model and direct instruction model, the different of physic resolving problem ability between the students that have critical thinking ability upper the average and the students that have critical thinking ability under the average, and the interaction of problem based learning model toward critical thinking ability and students’ physic resolving problem ability. This research was quasy experimental research that use critical thinking ability tests and physic resolving problem ability tests as the instruments. Result of the research showed that the students’ physic resolving problem ability by using problem based learning model was better than by using direct instruction model, students’ physic resolving problem ability and critical thinking ability upper the average showed better different and result than students’ critical thinking ability under the average, besides there was an interaction between problem based learning model and critical thinking ability in improving students’ physic resolving problem ability.

  10. A Critical Synthesis of Scientific Research on Business Models and Business Model Components

    Directory of Open Access Journals (Sweden)

    Roxana CLODNIȚCHI

    2017-12-01

    Full Text Available The current volatile economic environment, globalization and evermore shorter technology cycles impact the way business is done today. Business modelling proves itself as an instrument, which may impact decisively the success or failure of a business. This is why both the business and academic community critically address this issue. The aim of this article is to contribute to the development of a unifying research agenda by synthesising the most relevant scientific research and studies. The author reviewed and analysed the scientific theoretical framework on this subject from the past 15 years. The research result consists in a systematisation on past approaches on business modelling stressing the components as they are defined by contemporary scholars. By doing this, the author aims at reconciling the fragmented and only partially overlapping definition of the concept of “business model”.

  11. A Critical Agency Network Model for Building an Integrated Outreach Program

    Science.gov (United States)

    Kiyama, Judy Marquez; Lee, Jenny J.; Rhoades, Gary

    2012-01-01

    This study considers a distinct case of a college outreach program that integrates student affairs staff, academic administrators, and faculty across campus. The authors find that social networks and critical agency help to understand the integration of these various professionals and offer a critical agency network model of enacting change.…

  12. Dependence of critical exponents on θ parameter in anyon lattice model

    International Nuclear Information System (INIS)

    Protegenov, A.P.; Verbus, V.A.

    1992-08-01

    The critical behaviour in the Z N model with θ-parameter is considered in the Coulomb gas representation. We focus our attention on the dependence of the critical exponents of the correlation functions of the Z N -theory with θ=2π/N on the rank N of the group. (author). 20 refs

  13. Temperature dependence of critical magnetic fields for the Abelian Higgs model

    International Nuclear Information System (INIS)

    Magpantay, J.; Mukku, C.; Sayed, W.A.

    1981-05-01

    One loop temperature and external electromagnetic field effects on the Abelian Higgs model are studied using the momentum space heat kernel. We obtain expressions for the critical fields necessary for symmetry restoration at some finite temperature and display the critical B vs. T curve separating the broken and restored phases in the B-T plane. (author)

  14. Moving beyond Assessment to Improving Students' Critical Thinking Skills: A Model for Implementing Change

    Science.gov (United States)

    Haynes, Ada; Lisic, Elizabeth; Goltz, Michele; Stein, Barry; Harris, Kevin

    2016-01-01

    This research examines how the use of the CAT (Critical thinking Assessment Test) and involvement in CAT-Apps (CAT Applications within the discipline) training can serve as an important part of a faculty development model that assists faculty in the assessment of students' critical thinking skills and in the development of these skills within…

  15. A Multiscale Modeling System: Developments, Applications, and Critical Issues

    Science.gov (United States)

    Tao, Wei-Kuo; Lau, William; Simpson, Joanne; Chern, Jiun-Dar; Atlas, Robert; Khairoutdinov, David Randall Marat; Li, Jui-Lin; Waliser, Duane E.; Jiang, Jonathan; Hou, Arthur; hide

    2009-01-01

    The foremost challenge in parameterizing convective clouds and cloud systems in large-scale models are the many coupled dynamical and physical processes that interact over a wide range of scales, from microphysical scales to the synoptic and planetary scales. This makes the comprehension and representation of convective clouds and cloud systems one of the most complex scientific problems in Earth science. During the past decade, the Global Energy and Water Cycle Experiment (GEWEX) Cloud System Study (GCSS) has pioneered the use of single-column models (SCMs) and cloud-resolving models (CRMs) for the evaluation of the cloud and radiation parameterizations in general circulation models (GCMs; e.g., GEWEX Cloud System Science Team 1993). These activities have uncovered many systematic biases in the radiation, cloud and convection parameterizations of GCMs and have led to the development of new schemes (e.g., Zhang 2002; Pincus et al, 2003; Zhang and Wu 2003; Wu et al. 2003; Liang and Wu 2005; Wu and Liang 2005, and others). Comparisons between SCMs and CRMs using the same large-scale forcing derived from field campaigns have demonstrated that CRMs are superior to SCMs in the prediction of temperature and moisture tendencies (e.g., Das et al. 1999; Randall et al 2003b; Xie et al. 2005).

  16. Childhood Maltreatment, Shame-Proneness and Self-Criticism in Social Anxiety Disorder: A Sequential Mediational Model.

    Science.gov (United States)

    Shahar, Ben; Doron, Guy; Szepsenwol, Ohad

    2015-01-01

    Previous research has shown a robust link between emotional abuse and neglect with social anxiety symptoms. However, the mechanisms through which these links operate are less clear. We hypothesized a model in which early experiences of abuse and neglect create aversive shame states, internalized into a stable shame-based cognitive-affective schema. Self-criticism is conceptualized as a safety strategy designed to conceal flaws and prevent further experiences of shame. However, self-criticism maintains negative self-perceptions and insecurity in social situations. To provide preliminary, cross-sectional support for this model, a nonclinical community sample of 219 adults from Israel (110 females, mean age = 38.7) completed measures of childhood trauma, shame-proneness, self-criticism and social anxiety symptoms. A sequential mediational model showed that emotional abuse, but not emotional neglect, predicted shame-proneness, which in turn predicted self-criticism, which in turn predicted social anxiety symptoms. These results provide initial evidence supporting the role of shame and self-criticism in the development and maintenance of social anxiety disorder. The clinical implications of these findings are discussed. Previous research has shown that histories of emotional abuse and emotional neglect predict social anxiety symptoms, but the mechanisms that underlie these associations are not clear. Using psycho-evolutionary and emotion-focused perspectives, the findings of the current study suggest that shame and self-criticism play an important role in social anxiety and may mediate the link between emotional abuse and symptoms. These findings also suggest that therapeutic interventions specifically targeting shame and self-criticism should be incorporated into treatments for social anxiety, especially with socially anxious patients with abuse histories. Copyright © 2014 John Wiley & Sons, Ltd.

  17. A CRITICAL ASSESSMENT OF PHENOMENOLOGICAL MODELS UNCERTAINTIES FOR TURBIDITY CURRENTS

    OpenAIRE

    Ferreira da Costa, Henrique José; Rochinha, Fernando Alves

    2017-01-01

    Abstract. Turbidity currents have significantly contributed to the formation of oil reservoirs through massive transport and deposition of sediments in the offshore area during the past geological era. That motivates the seek for understanding these complex flows composed of carrier and disperse phases. In this regard, numerical simulations can be of great help in understanding the complex underlying physics of those turbulent flows. Two-fluid models allow the explicit consideration of both p...

  18. Towards a dynamic assessment of raw materials criticality: linking agent-based demand--with material flow supply modelling approaches.

    Science.gov (United States)

    Knoeri, Christof; Wäger, Patrick A; Stamp, Anna; Althaus, Hans-Joerg; Weil, Marcel

    2013-09-01

    Emerging technologies such as information and communication-, photovoltaic- or battery technologies are expected to increase significantly the demand for scarce metals in the near future. The recently developed methods to evaluate the criticality of mineral raw materials typically provide a 'snapshot' of the criticality of a certain material at one point in time by using static indicators both for supply risk and for the impacts of supply restrictions. While allowing for insights into the mechanisms behind the criticality of raw materials, these methods cannot account for dynamic changes in products and/or activities over time. In this paper we propose a conceptual framework intended to overcome these limitations by including the dynamic interactions between different possible demand and supply configurations. The framework integrates an agent-based behaviour model, where demand emerges from individual agent decisions and interaction, into a dynamic material flow model, representing the materials' stocks and flows. Within the framework, the environmental implications of substitution decisions are evaluated by applying life-cycle assessment methodology. The approach makes a first step towards a dynamic criticality assessment and will enhance the understanding of industrial substitution decisions and environmental implications related to critical metals. We discuss the potential and limitation of such an approach in contrast to state-of-the-art methods and how it might lead to criticality assessments tailored to the specific circumstances of single industrial sectors or individual companies. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. The LNT model provides the best approach for practical implementation of radiation protection.

    Science.gov (United States)

    Martin, C J

    2005-01-01

    This contribution argues the case that, at the present time, the linear-no-threshold (LNT) model provides the only rational framework on which practical radiation protection can be organized. Political, practical and healthcare difficulties with attempting to introduce an alternative approach, e.g. a threshold model, are discussed.

  20. Effectiveness of Video Modeling Provided by Mothers in Teaching Play Skills to Children with Autism

    Science.gov (United States)

    Besler, Fatma; Kurt, Onur

    2016-01-01

    Video modeling is an evidence-based practice that can be used to provide instruction to individuals with autism. Studies show that this instructional practice is effective in teaching many types of skills such as self-help skills, social skills, and academic skills. However, in previous studies, videos used in the video modeling process were…

  1. Possibilities and Limitations of Applying Software Reliability Growth Models to Safety- Critical Software

    International Nuclear Information System (INIS)

    Kim, Man Cheol; Jang, Seung Cheol; Ha, Jae Joo

    2006-01-01

    As digital systems are gradually introduced to nuclear power plants (NPPs), the need of quantitatively analyzing the reliability of the digital systems is also increasing. Kang and Sung identified (1) software reliability, (2) common-cause failures (CCFs), and (3) fault coverage as the three most critical factors in the reliability analysis of digital systems. For the estimation of the safety-critical software (the software that is used in safety-critical digital systems), the use of Bayesian Belief Networks (BBNs) seems to be most widely used. The use of BBNs in reliability estimation of safety-critical software is basically a process of indirectly assigning a reliability based on various observed information and experts' opinions. When software testing results or software failure histories are available, we can use a process of directly estimating the reliability of the software using various software reliability growth models such as Jelinski- Moranda model and Goel-Okumoto's nonhomogeneous Poisson process (NHPP) model. Even though it is generally known that software reliability growth models cannot be applied to safety-critical software due to small number of expected failure data from the testing of safety-critical software, we try to find possibilities and corresponding limitations of applying software reliability growth models to safety critical software

  2. Modelling Framework for the Identification of Critical Variables and Parameters under Uncertainty in the Bioethanol Production from Lignocellulose

    DEFF Research Database (Denmark)

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

    2011-01-01

    This study presents the development of a systematic modelling framework for identification of the most critical variables and parameters under uncertainty, evaluated on a lignocellulosic ethanol production case study. The systematic framework starts with: (1) definition of the objectives; (2....... Sensitivity analysis employs the standardized regression coefficient (SRC) method, which provides a global sensitivity measure, βi, thereby showing how much each parameter contributes to the variance (uncertainty) of the model predictions. Thus, identifying the most critical parameters involved in the process......, suitable for further analysis of the bioprocess. The uncertainty and sensitivity analysis identified the following most critical variables and parameters involved in the lignocellulosic ethanol production case study. For the operating cost, the enzyme loading showed the strongest impact, while reaction...

  3. A quantitative risk-based model for reasoning over critical system properties

    Science.gov (United States)

    Feather, M. S.

    2002-01-01

    This position paper suggests the use of a quantitative risk-based model to help support reeasoning and decision making that spans many of the critical properties such as security, safety, survivability, fault tolerance, and real-time.

  4. Effects of Some Neurobiological Factors in a Self-organized Critical Model Based on Neural Networks

    International Nuclear Information System (INIS)

    Zhou Liming; Zhang Yingyue; Chen Tianlun

    2005-01-01

    Based on an integrate-and-fire mechanism, we investigate the effect of changing the efficacy of the synapse, the transmitting time-delayed, and the relative refractoryperiod on the self-organized criticality in our neural network model.

  5. Reliability modeling of safety-critical network communication in a digitalized nuclear power plant

    International Nuclear Information System (INIS)

    Lee, Sang Hun; Kim, Hee Eun; Son, Kwang Seop; Shin, Sung Min; Lee, Seung Jun; Kang, Hyun Gook

    2015-01-01

    The Engineered Safety Feature-Component Control System (ESF-CCS), which uses a network communication system for the transmission of safety-critical information from group controllers (GCs) to loop controllers (LCs), was recently developed. However, the ESF-CCS has not been applied to nuclear power plants (NPPs) because the network communication failure risk in the ESF-CCS has yet to be fully quantified. Therefore, this study was performed to identify the potential hazardous states for network communication between GCs and LCs and to develop quantification schemes for various network failure causes. To estimate the risk effects of network communication failures in the ESF-CCS, a fault-tree model of an ESF-CCS signal failure in the containment spray actuation signal condition was developed for the case study. Based on a specified range of periodic inspection periods for network modules and the baseline probability of software failure, a sensitivity study was conducted to analyze the risk effect of network failure between GCs and LCs on ESF-CCS signal failure. This study is expected to provide insight into the development of a fault-tree model for network failures in digital I&C systems and the quantification of the risk effects of network failures for safety-critical information transmission in NPPs. - Highlights: • Network reliability modeling framework for digital I&C system in NPP is proposed. • Hazardous states of network protocol between GC and LC in ESF-CCS are identified. • Fault-tree model of ESF-CCS signal failure in ESF actuation condition is developed. • Risk effect of network failure on ESF-CCS signal failure is analyzed.

  6. Numerical estimation of wall friction ratio near the pseudo-critical point with CFD-models

    International Nuclear Information System (INIS)

    Angelucci, M.; Ambrosini, W.; Forgione, N.

    2013-01-01

    In this paper, the STAR-CCM+ CFD code is used in the attempt to reproduce the values of friction factor observed in experimental data at supercritical pressures at various operating conditions. A short survey of available data and correlations for smooth pipe friction in circular pipes puts the basis for the discussion, reporting observed trends of friction factor in the liquid-like and the gas-like regions and within the transitional region across the pseudo-critical temperature. For smooth pipes, a general decrease of the friction factor in the transitional region is reported, constituting one of the relevant effects to be predicted by the computational fluid-dynamic models. A limited number of low-Reynolds number models are adopted, making use of refined near-wall discretisation as required by the constraint y + < 1 at the wall. In particular, the Lien k–ε and the SST k–ω models are considered. The values of the wall shear stress calculated by the code are then post-processed on the basis of bulk fluid properties to obtain the Fanning and then the Darcy–Weisbach friction factors, based on their classical definitions. The obtained values are compared with those provided by experimental tests and correlations, finding a reasonable qualitative agreement. Expectedly, the agreement is better in the gas-like and liquid-like regions, where fluid property changes are moderate, than in the transitional region, where the trends provided by available correlations are reproduced only in a qualitative way

  7. The 1D Kondo lattice model at criticality

    International Nuclear Information System (INIS)

    Gulacsi, M.

    1998-01-01

    The transition from a ferromagnetic phase, to a disordered paramagnetic phase, which occurs in one-dimensional Kondo lattice models is described. The transition is the quantum order-disorder transition of the transverse-field Ising chain type, and reflects ferromagnetically ordered regions of localized spins being gradually destroyed as the coupling to the conduction electrons is reduced. For incommensurate conduction band fillings, the low-energy properties of the localized spins near the transition are dominated by anomalous ordered (disordered) regions of localized spins which survive into the ferromagnetic (paramagnetic) phase. (Copyright (1998) World Scientific Publishing Co. Pte. Ltd)

  8. The U(1)-Higgs model: critical behaviour in the confining-Higgs region

    International Nuclear Information System (INIS)

    Alonso, J.L.; Azcoiti, V.; Campos, I.; Ciria, J.C.; Cruz, A.; Iniguez, D.; Lesmes, F.; Piedrafita, C.; Rivero, A.; Tarancon, A.; Badoni, D.; Fernandez, L.A.; Munoz Sudupe, A.; Ruiz-Lorenzo, J.J.; Gonzalez-Arroyo, A.; Martinez, P.; Pech, J.; Tellez, P.

    1993-01-01

    We study numerically the critical properties of the U(1)-Higgs lattice model, with fixed Higgs modulus, in the region of small gauge coupling where the Higgs and confining phases merge. We find evidence for a first-order transition line that ends in a second-order point. By means of a rotation in parameter space we introduce thermodynamic magnitudes and critical exponents in close resemblance with simple models that show analogous critical behaviour. The measured data allow us to fit the critical exponents finding values in agreement with the mean-field prediction. The location of the critical point and the slope of the first-order line are accurately measured. (orig.)

  9. Neither as harmful as feared by critics nor as empowering as promised by providers: risk information offered direct to consumer by personal genomics companies.

    Science.gov (United States)

    Nordgren, Anders

    2014-01-01

    In this paper, I investigate ethical and policy aspects of the genetic services and web-rhetoric of companies offering genetic information direct to consumer, and I do so with a special focus on genetic risk information. On their websites, the companies stress that genetic risk testing for multifactorial complex medical conditions such as cardiovascular disease and cancer may empower the consumer and provide valuable input to personal identity. Critics maintain, on the other hand, that testing can be psychologically harmful, is of limited clinical and preventive value, and vulnerable to misinterpretation. I stress the importance of empirical studies in assessing the pros and cons of direct-to-consumer testing and point out that recent empirical studies indicate that this testing is neither as harmful as feared by critics nor as empowering as promised by the companies. However, the testing is not entirely harmless. Remaining problems include testing of third parties without consent and ownership of genotypic and phenotypic information. Moreover, the testing, although not particularly empowering, may still provide input to self-understanding that some people find valuable. Regarding policy-making, I suggest that self-regulation in terms of best practice guidelines may play an important role, but I also stress that national and international regulation may be necessary.

  10. FRAMES-2.0 Software System: Providing Password Protection and Limited Access to Models and Simulations

    International Nuclear Information System (INIS)

    Whelan, Gene; Pelton, Mitch A.

    2007-01-01

    One of the most important concerns for regulatory agencies is the concept of reproducibility (i.e., reproducibility means credibility) of an assessment. One aspect of reproducibility deals with tampering of the assessment. In other words, when multiple groups are engaged in an assessment, it is important to lock down the problem that is to be solved and/or to restrict the models that are to be used to solve the problem. The objective of this effort is to provide the U.S. Nuclear Regulatory Commission (NRC) with a means to limit user access to models and to provide a mechanism to constrain the conceptual site models (CSMs) when appropriate. The purpose is to provide the user (i.e., NRC) with the ability to ''lock down'' the CSM (i.e., picture containing linked icons), restrict access to certain models, or both.

  11. Welcoming expertise: Bereaved parents' perceptions of the parent-healthcare provider relationship when a critically ill child is admitted to the paediatric intensive care unit.

    Science.gov (United States)

    Butler, Ashleigh E; Copnell, Beverley; Hall, Helen

    2017-11-15

    Entering the paediatric intensive care unit with a critically ill child is a stressful experience for parents. In addition to fearing for their child's well-being, parents must navigate both a challenging environment and numerous new relationships with healthcare staff. How parents form relationships with staff and how they perceive both their own and the healthcare providers' roles in this early stage of their paediatric intensive care journey is currently unknown. This paper explores bereaved parents' perceptions of their role and their relationships with healthcare providers when their child is admitted to the intensive care unit, as part of a larger study exploring their experiences when their child dies in intensive care. A constructivist grounded theory approach was utilised to recruit 26 bereaved parents from 4 Australian intensive care units. Parents participated in audio-recorded, semi-structured interviews lasting 90-150min. All data were analysed using the constant comparative analysis processes, supported by theoretical memos. Upon admission, parents viewed healthcare providers as experts, both of their child's medical care and of the hospital system. This expertise was welcomed, with the parent-healthcare provider relationship developing around the child's need for medical care. Parents engaged in 2 key behaviours in their relationships with staff: prioritising survival, and learning 'the system'. Within each of these behaviours are several subcategories, including 'Stepping back', 'Accepting restrictions' and 'Deferring to medical advice'. The relationships between parents and staff shift and change across the child's admission and subsequent death in the paediatric intensive care unit. However, upon admission, this relationship centres around the child's potential survival and their need for medical care, and the parent's recognition of the healthcare staff as experts of both the child's care and the hospital system. Copyright © 2017 Australian

  12. [Critical of the additive model of the randomized controlled trial].

    Science.gov (United States)

    Boussageon, Rémy; Gueyffier, François; Bejan-Angoulvant, Theodora; Felden-Dominiak, Géraldine

    2008-01-01

    Randomized, double-blind, placebo-controlled clinical trials are currently the best way to demonstrate the clinical effectiveness of drugs. Its methodology relies on the method of difference (John Stuart Mill), through which the observed difference between two groups (drug vs placebo) can be attributed to the pharmacological effect of the drug being tested. However, this additive model can be questioned in the event of statistical interactions between the pharmacological and the placebo effects. Evidence in different domains has shown that the placebo effect can influence the effect of the active principle. This article evaluates the methodological, clinical and epistemological consequences of this phenomenon. Topics treated include extrapolating results, accounting for heterogeneous results, demonstrating the existence of several factors in the placebo effect, the necessity to take these factors into account for given symptoms or pathologies, as well as the problem of the "specific" effect.

  13. Oscillatory Behavior of Critical Amplitudes of the Gaussian Model on a Hierarchical Structure

    OpenAIRE

    Knezevic, Milan; Knezevic, Dragica

    1999-01-01

    We studied oscillatory behavior of critical amplitudes for the Gaussian model on a hierarchical structure presented by a modified Sierpinski gasket lattice. This model is known to display non-standard critical behavior on the lattice under study. The leading singular behavior of the correlation length $\\xi$ near the critical coupling $K=K_c$ is modulated by a function which is periodic in $\\ln|\\ln(K_c-K)|$. We have also shown that the common finite-size scaling hypothesis, according to which ...

  14. Modeling Acinetobacter baumannii wound infections: The critical role of iron

    Science.gov (United States)

    Fleming, Irma D.; Krezalek, Monika A.; Belogortseva, Natalia; Zaborin, Alexander; Defazio, Jennifer; Chandrasekar, Laxmipradha; Actis, Luis A.; Zaborina, Olga; Alverdy, John C.

    2016-01-01

    Background Acinetobacter baumannii has emerged as an increasingly important and successful opportunistic human pathogen due to its ability to withstand harsh environmental conditions, its characteristic virulence factors and quick adaptability to stress. Methods We developed a clinically relevant murine model of A. baumannii traumatic wound infection to determine the effect of local wound environment on A. baumannii virulence. Mice underwent rectus muscle crush injury combined with ischemia created by epigastric vessel ligation, followed by A. baumannii inoculation. Reiterative experiments were performed using 1) a mutant deficient in the production of the siderophore acinetobactin, or 2) iron supplementation of the wound milieu. Mice were euthanized 7 days later and rectus muscle analyzed for signs of clinical infection, HIF1α accumulation, bacterial abundance and colony morphotype. To determine the effect of wound milieu on bacterial virulence, the Galleria mellonella infection model was utilized. Results The combination of rectus muscle injury with ischemia and A. baumannii inoculation resulted in 100% incidence of clinical wound infection that was significantly higher compared to other groups (n=15/group, pbaumannii colonization (pbaumannii strains isolated from injured/ischemic muscle with clinical infection displayed a rough morphotype and a higher degree of virulence as judged by G. mellonella killing assay as compared to smooth morphotype colonies isolated from injured muscle without clinical infection (100% vs. 60%, n=30 Log-Rank test, p=0.0422). Iron supplementation prevented wound infection (n=30, pbaumannii wild type was replaced with its derivative mutant ΔBasD deficient in acinetobactin production. Conclusions The ability of A. baumannii to cause infections in traumatized wound relies on its ability to scavenge iron and can be prevented by iron supplementation to the wound milieu. PMID:28030490

  15. What are healthcare providers' understandings and experiences of compassion? The healthcare compassion model: a grounded theory study of healthcare providers in Canada.

    Science.gov (United States)

    Sinclair, Shane; Hack, Thomas F; Raffin-Bouchal, Shelley; McClement, Susan; Stajduhar, Kelli; Singh, Pavneet; Hagen, Neil A; Sinnarajah, Aynharan; Chochinov, Harvey Max

    2018-03-14

    Healthcare providers are considered the primary conduit of compassion in healthcare. Although most healthcare providers desire to provide compassion, and patients and families expect to receive it, an evidence-based understanding of the construct and its associated dimensions from the perspective of healthcare providers is needed. The aim of this study was to investigate healthcare providers' perspectives and experiences of compassion in order to generate an empirically derived, clinically informed model. Data were collected via focus groups with frontline healthcare providers and interviews with peer-nominated exemplary compassionate healthcare providers. Data were independently and collectively analysed by the research team in accordance with Straussian grounded theory. 57 healthcare providers were recruited from urban and rural palliative care services spanning hospice, home care, hospital-based consult teams, and a dedicated inpatient unit within Alberta, Canada. Five categories and 13 associated themes were identified, illustrated in the Healthcare Provider Compassion Model depicting the dimensions of compassion and their relationship to one another. Compassion was conceptualised as-a virtuous and intentional response to know a person, to discern their needs and ameliorate their suffering through relational understanding and action. An empirical foundation of healthcare providers' perspectives on providing compassionate care was generated. While the dimensions of the Healthcare Provider Compassion Model were congruent with the previously developed Patient Model, further insight into compassion is now evident. The Healthcare Provider Compassion Model provides a model to guide clinical practice and research focused on developing interventions, measures and resources to improve it. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly

  16. The Effect of Integrated Learning Model and Critical Thinking Skill of Science Learning Outcomes

    Science.gov (United States)

    Fazriyah, N.; Supriyati, Y.; Rahayu, W.

    2017-02-01

    This study aimed to determine the effect of integrated learning model and critical thinking skill toward science learning outcomes. The study was conducted in SDN Kemiri Muka 1 Depok in fifth grade school year 2014/2015 using cluster random sampling was done to 80 students. Retrieval of data obtained through tests and analysis by Variance (ANOVA) and two lines with the design treatment by level 2x2. The results showed that: (1) science learning outcomes students that given thematic integrated learning model is higher than in the group of students given fragmented learning model, (2) there is an interaction effect between critical thinking skills with integrated learning model, (3) for students who have high critical thinking skills, science learning outcomes students who given by thematic integrated learning model higher than fragmented learning model and (4) for students who have the ability to think critically low yield higher learning science fragmented model. The results of this study indicate that thematic learning model with critical thinking skills can improve science learning outcomes of students.

  17. Quantum-critical scaling of fidelity in 2D pairing models

    International Nuclear Information System (INIS)

    Adamski, Mariusz; Jȩdrzejewski, Janusz; Krokhmalskii, Taras

    2017-01-01

    The laws of quantum-critical scaling theory of quantum fidelity, dependent on the underlying system dimensionality D, have so far been verified in exactly solvable 1D models, belonging to or equivalent to interacting, quadratic (quasifree), spinless or spinfull, lattice-fermion models. The obtained results are so appealing that in quest for correlation lengths and associated universal critical indices ν, which characterize the divergence of correlation lengths on approaching critical points, one might be inclined to substitute the hard task of determining an asymptotic behavior at large distances of a two-point correlation function by an easier one, of determining the quantum-critical scaling of the quantum fidelity. However, the role of system's dimensionality has been left as an open problem. Our aim in this paper is to fill up this gap, at least partially, by verifying the laws of quantum-critical scaling theory of quantum fidelity in a 2D case. To this end, we study correlation functions and quantum fidelity of 2D exactly solvable models, which are interacting, quasifree, spinfull, lattice-fermion models. The considered 2D models exhibit new, as compared with 1D ones, features: at a given quantum-critical point there exists a multitude of correlation lengths and multiple universal critical indices ν, since these quantities depend on spatial directions, moreover, the indices ν may assume larger values. These facts follow from the obtained by us analytical asymptotic formulae for two-point correlation functions. In such new circumstances we discuss the behavior of quantum fidelity from the perspective of quantum-critical scaling theory. In particular, we are interested in finding out to what extent the quantum fidelity approach may be an alternative to the correlation-function approach in studies of quantum-critical points beyond 1D.

  18. Social models provide a norm of appropriate food intake for young women.

    Directory of Open Access Journals (Sweden)

    Lenny R Vartanian

    Full Text Available It is often assumed that social models influence people's eating behavior by providing a norm of appropriate food intake, but this hypothesis has not been directly tested. In three experiments, female participants were exposed to a low-intake model, a high-intake model, or no model (control condition. Experiments 1 and 2 used a remote-confederate manipulation and were conducted in the context of a cookie taste test. Experiment 3 used a live confederate and was conducted in the context of a task during which participants were given incidental access to food. Participants also rated the extent to which their food intake was influenced by a variety of factors (e.g., hunger, taste, how much others ate. In all three experiments, participants in the low-intake conditions ate less than did participants in the high-intake conditions, and also reported a lower perceived norm of appropriate intake. Furthermore, perceived norms of appropriate intake mediated the effects of the social model on participants' food intake. Despite the observed effects of the social models, participants were much more likely to indicate that their food intake was influenced by taste and hunger than by the behavior of the social models. Thus, social models appear to influence food intake by providing a norm of appropriate eating behavior, but people may be unaware of the influence of a social model on their behavior.

  19. Quantitative physical models of volcanic phenomena for hazards assessment of critical infrastructures

    Science.gov (United States)

    Costa, Antonio

    2016-04-01

    Volcanic hazards may have destructive effects on economy, transport, and natural environments at both local and regional scale. Hazardous phenomena include pyroclastic density currents, tephra fall, gas emissions, lava flows, debris flows and avalanches, and lahars. Volcanic hazards assessment is based on available information to characterize potential volcanic sources in the region of interest and to determine whether specific volcanic phenomena might reach a given site. Volcanic hazards assessment is focussed on estimating the distances that volcanic phenomena could travel from potential sources and their intensity at the considered site. Epistemic and aleatory uncertainties strongly affect the resulting hazards assessment. Within the context of critical infrastructures, volcanic eruptions are rare natural events that can create severe hazards. In addition to being rare events, evidence of many past volcanic eruptions is poorly preserved in the geologic record. The models used for describing the impact of volcanic phenomena generally represent a range of model complexities, from simplified physics based conceptual models to highly coupled thermo fluid dynamical approaches. Modelling approaches represent a hierarchy of complexity, which reflects increasing requirements for well characterized data in order to produce a broader range of output information. In selecting models for the hazard analysis related to a specific phenomenon, questions that need to be answered by the models must be carefully considered. Independently of the model, the final hazards assessment strongly depends on input derived from detailed volcanological investigations, such as mapping and stratigraphic correlations. For each phenomenon, an overview of currently available approaches for the evaluation of future hazards will be presented with the aim to provide a foundation for future work in developing an international consensus on volcanic hazards assessment methods.

  20. Critical manifold of the Potts model: Exact results and homogeneity approximation

    Science.gov (United States)

    Wu, F. Y.; Guo, Wenan

    2012-08-01

    The q-state Potts model has stood at the frontier of research in statistical mechanics for many years. In the absence of a closed-form solution, much of the past effort has focused on locating its critical manifold, trajectory in the parameter {q,eJ} space where J is the reduced interaction, along which the free energy is singular. However, except in isolated cases, antiferromagnetic (AF) models with J0. We also locate its critical frontier for JLondon Ser. A 388, 43 (1982)]. For the honeycomb lattice we show that the known critical frontier holds for all J, and determine its critical qc=(1)/(2)(3+5)=2.61803 beyond which there is no transition. For the triangular lattice we confirm the known critical frontier to hold only for J>0. More generally we consider the centered-triangle (CT) and Union-Jack (UJ) lattices consisting of mixed J and K interactions, and deduce critical manifolds under homogeneity hypotheses. For K=0 the CT lattice is the diced lattice, and we determine its critical manifold for all J and find qc=3.32472. For K=0 the UJ lattice is the square lattice and from this we deduce both the J>0 and J<0 critical manifolds and qc=3. Our theoretical predictions are compared with recent numerical results.

  1. Improving Junior High Schools’ Critical Thinking Skills Based on Test Three Different Models of Learning

    Directory of Open Access Journals (Sweden)

    Nur Miftahul Fuad

    2017-01-01

    Full Text Available The aims of this study were (1 to find out the differences in critical thinking skills among students who were given three different learning models: differentiated science inquiry combined with mind map, differentiated science inquiry model, and conventional model, (2 to find out the differences of critical thinking skills among male and female students. This study is a quasi-experimental research with pretest-posttest nonequivalent control group design. The population in this research is the seventh grade students of junior high schools in Kediri, Indonesia. The sample of the research is in the number of 96 students distributed in three classes at different schools. The data of critical thinking skills are gained from test scores and then analyzed using descriptive and inferential statistics through ANCOVA. The results of research revealed that there are different skills in critical thinking in different models. The highest skills in critical thinking are reached by students who were given differentiated science inquiry model combined with mind map in their learning. There are also differences in critical thinking skills between male and female students.

  2. Value-added strategy models to provide quality services in senior health business.

    Science.gov (United States)

    Yang, Ya-Ting; Lin, Neng-Pai; Su, Shyi; Chen, Ya-Mei; Chang, Yao-Mao; Handa, Yujiro; Khan, Hafsah Arshed Ali; Elsa Hsu, Yi-Hsin

    2017-06-20

    The rapid population aging is now a global issue. The increase in the elderly population will impact the health care industry and health enterprises; various senior needs will promote the growth of the senior health industry. Most senior health studies are focused on the demand side and scarcely on supply. Our study selected quality enterprises focused on aging health and analyzed different strategies to provide excellent quality services to senior health enterprises. We selected 33 quality senior health enterprises in Taiwan and investigated their excellent quality services strategies by face-to-face semi-structured in-depth interviews with CEO and managers of each enterprise in 2013. A total of 33 senior health enterprises in Taiwan. Overall, 65 CEOs and managers of 33 enterprises were interviewed individually. None. Core values and vision, organization structure, quality services provided, strategies for quality services. This study's results indicated four type of value-added strategy models adopted by senior enterprises to offer quality services: (i) residential care and co-residence model, (ii) home care and living in place model, (iii) community e-business experience model and (iv) virtual and physical portable device model. The common part in these four strategy models is that the services provided are elderly centered. These models offer virtual and physical integrations, and also offer total solutions for the elderly and their caregivers. Through investigation of successful strategy models for providing quality services to seniors, we identified opportunities to develop innovative service models and successful characteristics, also policy implications were summarized. The observations from this study will serve as a primary evidenced base for enterprises developing their senior market and, also for promoting the value co-creation possibility through dialogue between customers and those that deliver service. © The Author 2017. Published by Oxford

  3. Detecting critical state before phase transition of complex biological systems by hidden Markov model.

    Science.gov (United States)

    Chen, Pei; Liu, Rui; Li, Yongjun; Chen, Luonan

    2016-07-15

    Identifying the critical state or pre-transition state just before the occurrence of a phase transition is a challenging task, because the state of the system may show little apparent change before this critical transition during the gradual parameter variations. Such dynamics of phase transition is generally composed of three stages, i.e. before-transition state, pre-transition state and after-transition state, which can be considered as three different Markov processes. By exploring the rich dynamical information provided by high-throughput data, we present a novel computational method, i.e. hidden Markov model (HMM) based approach, to detect the switching point of the two Markov processes from the before-transition state (a stationary Markov process) to the pre-transition state (a time-varying Markov process), thereby identifying the pre-transition state or early-warning signals of the phase transition. To validate the effectiveness, we apply this method to detect the signals of the imminent phase transitions of complex systems based on the simulated datasets, and further identify the pre-transition states as well as their critical modules for three real datasets, i.e. the acute lung injury triggered by phosgene inhalation, MCF-7 human breast cancer caused by heregulin and HCV-induced dysplasia and hepatocellular carcinoma. Both functional and pathway enrichment analyses validate the computational results. The source code and some supporting files are available at https://github.com/rabbitpei/HMM_based-method lnchen@sibs.ac.cn or liyj@scut.edu.cn Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  4. Fuzzy clustering: critical analysis of the contextual mechanisms employed by three neural network models

    Science.gov (United States)

    Baraldi, Andrea; Parmiggiani, Flavio

    1996-06-01

    According to the following definition, taken from the literature, a fuzzy clustering mechanism allows the same input pattern to belong to multiple categories to different degrees. Many clustering neural network (NN) models claim to feature fuzzy properties, but several of them (like the Fuzzy ART model) do not satisfy this definition. Vice versa, we believe that Kohonen's Self-Organizing Map, SOM, satisfies the definition provided above, even though this NN model is well-known to (robustly) perform topologically ordered mapping rather than fuzzy clustering. This may sound as a paradox if we consider that several fuzzy NN models (such as the Fuzzy Learning Vector Quantization, FLVQ, which was first called Fuzzy Kohonen Clustering Network, FKCN) were originally developed to enhance Kohonen's models (such as SOM and the vector quantization model, VQ). The fuzziness of SOM indicates that a network of processing elements (PEs) can verify the fuzzy clustering definition when it exploits local rules which are biologically plausible (such as the Kohonen bubble strategy). This is equivalent to state that the exploitation of the fuzzy set theory in the development of complex systems (e.g., clustering NNs) may provide new mathematical tools (e.g., the definition of membership function) to simulate the behavior of those cooperative/competitive mechanisms already identified by neurophysiological studies. When a biologically plausible cooperative/competitive strategy is pursued effectively, neighboring PEs become mutually coupled to gain sensitivity to contextual effects. PEs which are mutually coupled are affected by vertical (inter-layer) as well as horizontal (intra-layer) connections. To summarize, we suggest to relate the study of fuzzy clustering mechanisms to the multi-disciplinary science of complex systems, with special regard to the investigation of the cooperative/competitive local rules employed by complex systems to gain sensitivity to contextual effects in

  5. Long-term modelling of nitrogen turnover and critical loads in a forested catchment using the INCA model

    Directory of Open Access Journals (Sweden)

    J.-J. Langusch

    2002-01-01

    Full Text Available Many forest ecosystems in Central Europe have reached the status of N saturation due to chronically high N deposition. In consequence, the NO3 leaching into ground- and surface waters is often substantial. Critical loads have been defined to abate the negative consequences of the NO3 leaching such as soil acidification and nutrient losses. The steady state mass balance method is normally used to calculate critical loads for N deposition in forest ecosystems. However, the steady state mass balance approach is limited because it does not take into account hydrology and the time until the steady state is reached. The aim of this study was to test the suitability of another approach: the dynamic model INCA (Integrated Nitrogen Model for European Catchments. Long-term effects of changing N deposition and critical loads for N were simulated using INCA for the Lehstenbach spruce catchment (Fichtelgebirge, NE Bavaria, Germany under different hydrological conditions. Long-term scenarios of either increasing or decreasing N deposition indicated that, in this catchment, the response of nitrate concentrations in runoff to changing N deposition is buffered by a large groundwater reservoir. The critical load simulated by the INCA model with respect to a nitrate concentration of 0.4 mg N l–1 as threshold value in runoff was 9.7 kg N ha–1yr–1 compared to 10 kg ha–1yr–1 for the steady state model. Under conditions of lower precipitation (520 mm the resulting critical load was 7.7 kg N ha–1yr–1 , suggesting the necessity to account for different hydrological conditions when calculating critical loads. The INCA model seems to be suitable to calculate critical loads for N in forested catchments under varying hydrological conditions e.g. as a consequence of climate change. Keywords: forest ecosystem, N saturation, critical load, modelling, long-term scenario, nitrate leaching, critical loads reduction, INCA

  6. The critical 1-arm exponent for the ferromagnetic Ising model on the Bethe lattice

    Science.gov (United States)

    Heydenreich, Markus; Kolesnikov, Leonid

    2018-04-01

    We consider the ferromagnetic nearest-neighbor Ising model on regular trees (Bethe lattice), which is well-known to undergo a phase transition in the absence of an external magnetic field. The behavior of the model at critical temperature can be described in terms of various critical exponents; one of them is the critical 1-arm exponent ρ which characterizes the rate of decay of the (root) magnetization as a function of the distance to the boundary. The crucial quantity we analyze in this work is the thermal expectation of the root spin on a finite subtree, where the expected value is taken with respect to a probability measure related to the corresponding finite-volume Hamiltonian with a fixed boundary condition. The spontaneous magnetization, which is the limit of this thermal expectation in the distance between the root and the boundary (i.e., in the height of the subtree), is known to vanish at criticality. We are interested in a quantitative analysis of the rate of this convergence in terms of the critical 1-arm exponent ρ. Therefore, we rigorously prove that ⟨σ0⟩ n +, the thermal expectation of the root spin at the critical temperature and in the presence of the positive boundary condition, decays as ⟨σ0 ⟩ n +≈n-1/2 (in a rather sharp sense), where n is the height of the tree. This establishes the 1-arm critical exponent for the Ising model on regular trees (ρ =1/2 ).

  7. A FORMATIVE ASSESSMENT MODEL OF CRITICAL THINKING IN MATHEMATICS LEARNING IN JUNIOR HIGH SCHOOL

    Directory of Open Access Journals (Sweden)

    R. Rosnawati

    2015-12-01

    Full Text Available This study aims to obtain a valid and reliable formative evaluation model of critical thinking. The method used in this research was the research and development by integrating Borg & Gall's model and  Plomp's development model. The ten steps Borg & Gall’s model were modified into five stages as the stages in the Plomp's model. The subjects in this study were 1,446 students of junior high schools in DIY, 14 mathematics teacher, and six experts. The content validity employed was expert judgment, the empirical validity and reliability used were loading factor, item analysis used PCM 1PL, and the relationship between disposition and critical thinking skill used was structural equation modeling (SEM. The developed formative evaluation model is the procedural model. There are five aspects of critical thinking skill: mathematic reasoning, interpretation, analysis, evaluation, and inference, which entirely composed of 42 items. The validity of the critical thinking skill instruments achieves a significance degree as indicated by the lowest and the highest loading factors of 0.38 and 0.74 subsequently, the reliability of every aspect in a good category. The average level of difficulty is 0.00 with the standard deviation of 0.45 which is in a good category. The peer assessment questionnaire of critical thinking disposition consists of seven aspects: truth-seeking, open-minded, analysis, systematic, self-confidence, inquisitiveness, and maturity with 23 items. The critical thinking disposition validity achieves the significance degree as indicated by the lowest and the high factor loading of 0.66 and 0.76 subsequently, and the reliability of every aspect in a good category. Based on the analysis of the structural equation model, the model fits the data.

  8. A Complex of Business Process Management Models for a Service-Providing IT Company

    OpenAIRE

    Yatsenko Roman M.; Balykov Oleksii H.

    2017-01-01

    The article presents an analysis of a complex of business process management models that are designed to improve the performance of service-providing IT companies. This class of enterprises was selected because of their significant contribution to the Ukrainian economy: third place in the structure of exports, significant budget revenues, high development dynamics, and prospects in the global marketplace. The selected complex of models is designed as a sequence of stages that must be accompli...

  9. Tissue material properties and computational modelling of the human tibiofemoral joint: a critical review

    Directory of Open Access Journals (Sweden)

    Abby E. Peters

    2018-01-01

    Full Text Available Understanding how structural and functional alterations of individual tissues impact on whole-joint function is challenging, particularly in humans where direct invasive experimentation is difficult. Finite element (FE computational models produce quantitative predictions of the mechanical and physiological behaviour of multiple tissues simultaneously, thereby providing a means to study changes that occur through healthy ageing and disease such as osteoarthritis (OA. As a result, significant research investment has been placed in developing such models of the human knee. Previous work has highlighted that model predictions are highly sensitive to the various inputs used to build them, particularly the mathematical definition of material properties of biological tissues. The goal of this systematic review is two-fold. First, we provide a comprehensive summation and evaluation of existing linear elastic material property data for human tibiofemoral joint tissues, tabulating numerical values as a reference resource for future studies. Second, we review efforts to model tibiofemoral joint mechanical behaviour through FE modelling with particular focus on how studies have sourced tissue material properties. The last decade has seen a renaissance in material testing fuelled by development of a variety of new engineering techniques that allow the mechanical behaviour of both soft and hard tissues to be characterised at a spectrum of scales from nano- to bulk tissue level. As a result, there now exists an extremely broad range of published values for human tibiofemoral joint tissues. However, our systematic review highlights gaps and ambiguities that mean quantitative understanding of how tissue material properties alter with age and OA is limited. It is therefore currently challenging to construct FE models of the knee that are truly representative of a specific age or disease-state. Consequently, recent tibiofemoral joint FE models have been highly

  10. Tissue material properties and computational modelling of the human tibiofemoral joint: a critical review.

    Science.gov (United States)

    Peters, Abby E; Akhtar, Riaz; Comerford, Eithne J; Bates, Karl T

    2018-01-01

    Understanding how structural and functional alterations of individual tissues impact on whole-joint function is challenging, particularly in humans where direct invasive experimentation is difficult. Finite element (FE) computational models produce quantitative predictions of the mechanical and physiological behaviour of multiple tissues simultaneously, thereby providing a means to study changes that occur through healthy ageing and disease such as osteoarthritis (OA). As a result, significant research investment has been placed in developing such models of the human knee. Previous work has highlighted that model predictions are highly sensitive to the various inputs used to build them, particularly the mathematical definition of material properties of biological tissues. The goal of this systematic review is two-fold. First, we provide a comprehensive summation and evaluation of existing linear elastic material property data for human tibiofemoral joint tissues, tabulating numerical values as a reference resource for future studies. Second, we review efforts to model tibiofemoral joint mechanical behaviour through FE modelling with particular focus on how studies have sourced tissue material properties. The last decade has seen a renaissance in material testing fuelled by development of a variety of new engineering techniques that allow the mechanical behaviour of both soft and hard tissues to be characterised at a spectrum of scales from nano- to bulk tissue level. As a result, there now exists an extremely broad range of published values for human tibiofemoral joint tissues. However, our systematic review highlights gaps and ambiguities that mean quantitative understanding of how tissue material properties alter with age and OA is limited. It is therefore currently challenging to construct FE models of the knee that are truly representative of a specific age or disease-state. Consequently, recent tibiofemoral joint FE models have been highly generic in terms of

  11. Critical percolation in the slow cooling of the bi-dimensional ferromagnetic Ising model

    Science.gov (United States)

    Ricateau, Hugo; Cugliandolo, Leticia F.; Picco, Marco

    2018-01-01

    We study, with numerical methods, the fractal properties of the domain walls found in slow quenches of the kinetic Ising model to its critical temperature. We show that the equilibrium interfaces in the disordered phase have critical percolation fractal dimension over a wide range of length scales. We confirm that the system falls out of equilibrium at a temperature that depends on the cooling rate as predicted by the Kibble-Zurek argument and we prove that the dynamic growing length once the cooling reaches the critical point satisfies the same scaling. We determine the dynamic scaling properties of the interface winding angle variance and we show that the crossover between critical Ising and critical percolation properties is determined by the growing length reached when the system fell out of equilibrium.

  12. A Multi-scale Modeling System: Developments, Applications and Critical Issues

    Science.gov (United States)

    Tao, Wei-Kuo; Chern, Jiundar; Atlas, Robert; Randall, David; Lin, Xin; Khairoutdinov, Marat; Li, Jui-Lin; Waliser, Duane E.; Hou, Arthur; Peters-Lidard, Christa; hide

    2006-01-01

    A multi-scale modeling framework (MMF), which replaces the conventional cloud parameterizations with a cloud-resolving model (CRM) in each grid column of a GCM, constitutes a new and promising approach. The MMF can provide for global coverage and two-way interactions between the CRMs and their parent GCM. The GCM allows global coverage and the CRM allows explicit simulation of cloud processes and their interactions with radiation and surface processes. A new MMF has been developed that is based the Goddard finite volume GCM (fvGCM) and the Goddard Cumulus Ensemble (GCE) model. This Goddard MMF produces many features that are similar to another MMF that was developed at Colorado State University (CSU), such as an improved .surface precipitation pattern, better cloudiness, improved diurnal variability over both oceans and continents, and a stronger, propagating Madden-Julian oscillation (MJO) compared to their parent GCMs using conventional cloud parameterizations. Both MMFs also produce a precipitation bias in the western Pacific during Northern Hemisphere summer. However, there are also notable differences between two MMFs. For example, the CSU MMF simulates less rainfall over land than its parent GCM. This is why the CSU MMF simulated less overall global rainfall than its parent GCM. The Goddard MMF overestimates global rainfall because of its oceanic component. Some critical issues associated with the Goddard MMF are presented in this paper.

  13. Polychromatic Arm Exponents for the Critical Planar FK-Ising Model

    Science.gov (United States)

    Wu, Hao

    2018-03-01

    Schramm-Loewner evolution (SLE) is a one-parameter family of random planar curves introduced by Schramm in 1999 as the candidates for the scaling limits of the interfaces in the planar critical lattice models. This is the only possible process with conformal invariance and a certain "domain Markov property". In 2010, Chelkak and Smirnov proved the conformal invariance of the scaling limits of the critial planar FK-Ising model which gave the convergence of the interface to {SLE}_{16/3}. We derive the arm exponents of {SLE}_{κ } for κ \\in (4,8). Combining with the convergence of the interface, we derive the arm exponents of the critical FK-Ising model. We obtain six different patterns of boundary arm exponents and three different patterns of interior arm exponents of the critical planar FK-Ising model on the square lattice.

  14. Modeling of critical experiments employing Raschig rings in uranyl nitrate solution

    International Nuclear Information System (INIS)

    Tanner, J.E.

    1989-01-01

    Four critical experiments employing borated glass rings in concentrated uranyl nitrate solution yielded k eff higher by 0. 04 when modeled with a flux-weighted, homogenized cross section set than when modeled with discrete rings. k eff varied by 0.014 for a 10% boron uncertainty and by up to 0.04 for a 10% packing fraction uncertainty

  15. Critical Thinking and Political Participation: The Development and Assessment of a Causal Model.

    Science.gov (United States)

    Guyton, Edith M.

    An assessment of a four-stage conceptual model reveals that critical thinking has indirect positive effects on political participation through its direct effects on personal control, political efficacy, and democratic attitudes. The model establishes causal relationships among selected personality variables (self-esteem, personal control, and…

  16. A comparison of empirical and modeled nitrogen critical loads for Mediterranean forests and shrublands in California

    Science.gov (United States)

    M.E. Fenn; H.-D. Nagel; I. Koseva; J. Aherne; S.E. Jovan; L.H. Geiser; A. Schlutow; T. Scheuschner; A. Bytnerowicz; B.S. Gimeno; F. Yuan; S.A. Watmough; E.B. Allen; R.F. Johnson; T. Meixner

    2014-01-01

    Nitrogen (N) deposition is impacting a number of ecosystem types in California. Critical loads (CLs) for N deposition determined for mixed conifer forests and chaparral/oak woodlands in the Sierra Nevada Mountains of California and the San Bernardino Mountains in southern California using empirical and various modelling approaches were compared. Models used included...

  17. Critical behavior of the quantum spin- {1}/{2} anisotropic Heisenberg model

    Science.gov (United States)

    Sousa, J. Ricardo de

    A two-step renormalization group approach - a decimation followed by an effective field renormalization group (EFRG) - is proposed in this work to study the critical behavior of the quantum spin- {1}/{2} anisotropic Heisenberg model. The new method is illustrated by employing approximations in which clusters with one, two and three spins are used. The values of the critical parameter and critical exponent, in two- and three-dimensional lattices, for the Ising and isotropic Heisenberg limits are calculated and compared with other renormalization group approaches and exact (or series) results.

  18. A Structural Model for a Self-Assembled Nanotube Provides Insight into Its Exciton Dynamics

    Science.gov (United States)

    2016-01-01

    The design and synthesis of functional self-assembled nanostructures is frequently an empirical process fraught with critical knowledge gaps about atomic-level structure in these noncovalent systems. Here, we report a structural model for a semiconductor nanotube formed via the self-assembly of naphthalenediimide-lysine (NDI-Lys) building blocks determined using experimental 13C–13C and 13C–15N distance restraints from solid-state nuclear magnetic resonance supplemented by electron microscopy and X-ray powder diffraction data. The structural model reveals a two-dimensional-crystal-like architecture of stacked monolayer rings each containing ∼50 NDI-Lys molecules, with significant π-stacking interactions occurring both within the confines of the ring and along the long axis of the tube. Excited-state delocalization and energy transfer are simulated for the nanotube based on time-dependent density functional theory and an incoherent hopping model. Remarkably, these calculations reveal efficient energy migration from the excitonic bright state, which is in agreement with the rapid energy transfer within NDI-Lys nanotubes observed previously using fluorescence spectroscopy. PMID:26120375

  19. Using Models to Provide Predicted Ranges for Building-Human Interfaces: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Long, N.; Scheib, J.; Pless, S.; Schott, M.

    2013-09-01

    Most building energy consumption dashboards provide only a snapshot of building performance; whereas some provide more detailed historic data with which to compare current usage. This paper will discuss the Building Agent(tm) platform, which has been developed and deployed in a campus setting at the National Renewable Energy Laboratory as part of an effort to maintain the aggressive energyperformance achieved in newly constructed office buildings and laboratories. The Building Agent(tm) provides aggregated and coherent access to building data, including electric energy, thermal energy, temperatures, humidity, and lighting levels, and occupant feedback, which are displayed in various manners for visitors, building occupants, facility managers, and researchers. This paper focuseson the development of visualizations for facility managers, or an energy performance assurance role, where metered data are used to generate models that provide live predicted ranges of building performance by end use. These predicted ranges provide simple, visual context for displayed performance data without requiring users to also assess historical information or trends. Several energymodelling techniques were explored including static lookup-based performance targets, reduced-order models derived from historical data using main effect variables such as solar radiance for lighting performance, and integrated energy models using a whole-building energy simulation program.

  20. Critical phase for the antiferromagnetic Z(5) model on a square lattice

    International Nuclear Information System (INIS)

    Baltar, V.L.; Carneiro, G.M.; Pol, M.E.; Zagury, N.

    1983-04-01

    The existence of a critical phase for the antiferromagnetic Z(5) model on a square lattice is suggested based on results of Monte Carlo (MC) simulations and of Migdal Kadanoff Renormalization Group calculations (MKRG). The MKRG simulates a line of fixed points which it is interpreted as the locus of attraction of a critical phase. The MC simulations are compatible with this interpretation. (Author) [pt

  1. Critical behaviour of the Ginzburg-Landau model in the type II region

    CERN Document Server

    Kajantie, K.; Neuhaus, T.; Rajantie, A.; Rummukainen, K.

    2002-01-01

    We study the critical behaviour of the three-dimensional U(1) gauge+Higgs theory (Ginzburg-Landau model) at large scalar self-coupling \\lambda (``type II region'') by measuring various correlation lengths as well as the Abrikosov-Nielsen-Olesen vortex tension. We identify different scaling regions as the transition is approached from below, and carry out detailed comparisons with the criticality of the 3d O(2) symmetric scalar theory.

  2. Self-organized criticality, plasticity and sensorimotor coupling. Explorations with a neurorobotic model in a behavioural preference task.

    Directory of Open Access Journals (Sweden)

    Miguel Aguilera

    Full Text Available During the last two decades, analysis of 1/ƒ noise in cognitive science has led to a considerable progress in the way we understand the organization of our mental life. However, there is still a lack of specific models providing explanations of how 1/ƒ noise is generated in coupled brain-body-environment systems, since existing models and experiments typically target either externally observable behaviour or isolated neuronal systems but do not address the interplay between neuronal mechanisms and sensorimotor dynamics. We present a conceptual model of a minimal neurorobotic agent solving a behavioural task that makes it possible to relate mechanistic (neurodynamic and behavioural levels of description. The model consists of a simulated robot controlled by a network of Kuramoto oscillators with homeostatic plasticity and the ability to develop behavioural preferences mediated by sensorimotor patterns. With only three oscillators, this simple model displays self-organized criticality in the form of robust 1/ƒ noise and a wide multifractal spectrum. We show that the emergence of self-organized criticality and 1/ƒ noise in our model is the result of three simultaneous conditions: a non-linear interaction dynamics capable of generating stable collective patterns, b internal plastic mechanisms modulating the sensorimotor flows, and c strong sensorimotor coupling with the environment that induces transient metastable neurodynamic regimes. We carry out a number of experiments to show that both synaptic plasticity and strong sensorimotor coupling play a necessary role, as constituents of self-organized criticality, in the generation of 1/ƒ noise. The experiments also shown to be useful to test the robustness of 1/ƒ scaling comparing the results of different techniques. We finally discuss the role of conceptual models as mediators between nomothetic and mechanistic models and how they can inform future experimental research where self

  3. Self-organized criticality, plasticity and sensorimotor coupling. Explorations with a neurorobotic model in a behavioural preference task.

    Science.gov (United States)

    Aguilera, Miguel; Barandiaran, Xabier E; Bedia, Manuel G; Seron, Francisco

    2015-01-01

    During the last two decades, analysis of 1/ƒ noise in cognitive science has led to a considerable progress in the way we understand the organization of our mental life. However, there is still a lack of specific models providing explanations of how 1/ƒ noise is generated in coupled brain-body-environment systems, since existing models and experiments typically target either externally observable behaviour or isolated neuronal systems but do not address the interplay between neuronal mechanisms and sensorimotor dynamics. We present a conceptual model of a minimal neurorobotic agent solving a behavioural task that makes it possible to relate mechanistic (neurodynamic) and behavioural levels of description. The model consists of a simulated robot controlled by a network of Kuramoto oscillators with homeostatic plasticity and the ability to develop behavioural preferences mediated by sensorimotor patterns. With only three oscillators, this simple model displays self-organized criticality in the form of robust 1/ƒ noise and a wide multifractal spectrum. We show that the emergence of self-organized criticality and 1/ƒ noise in our model is the result of three simultaneous conditions: a) non-linear interaction dynamics capable of generating stable collective patterns, b) internal plastic mechanisms modulating the sensorimotor flows, and c) strong sensorimotor coupling with the environment that induces transient metastable neurodynamic regimes. We carry out a number of experiments to show that both synaptic plasticity and strong sensorimotor coupling play a necessary role, as constituents of self-organized criticality, in the generation of 1/ƒ noise. The experiments also shown to be useful to test the robustness of 1/ƒ scaling comparing the results of different techniques. We finally discuss the role of conceptual models as mediators between nomothetic and mechanistic models and how they can inform future experimental research where self-organized critically includes

  4. Scaling, phase transitions, and nonuniversality in a self-organized critical cellular-automaton model

    International Nuclear Information System (INIS)

    Christensen, K.; Olami, Z.

    1992-01-01

    We present a two-dimensional continuous cellular automaton that is equivalent to a driven spring-block model. Both the conservation and the anisotropy in the model are controllable quantities. Above a critical level of conservation, the model exhibits self-organized criticality. The self-organization of this system and hence the critical exponents depend on the conservation and the boundary conditions. In the critical isotropic nonconservative phase, the exponents change continuously as a function of conservation. Furthermore, the exponents vary continuously when changing the boundary conditions smoothly. Consequently, there is no universality of the critical exponents. We discuss the relevance of this for earthquakes. Introducing anisotropy changes the scaling of the distribution function, but not the power-law exponent. We explore the phase diagram of this model. We find that at low conservation levels a localization transition occurs. We see two additional phase transitions. The first is seen when moving from the conservative into the nonconservative model. The second appears when passing from the anisotropic two-dimensional system to the purely one-dimensional system

  5. Comparing consumer-directed and agency models for providing supportive services at home.

    Science.gov (United States)

    Benjamin, A E; Matthias, R; Franke, T M

    2000-04-01

    To examine the service experiences and outcomes of low-income Medicaid beneficiaries with disabilities under two different models for organizing home-based personal assistance services: agency-directed and consumer-directed. A survey of a random sample of 1,095 clients, age 18 and over, who receive services in California's In-Home Supportive Services (IHSS) program funded primarily by Medicaid. Other data were obtained from the California Management and Payrolling System (CMIPS). The sample was stratified by service model (agency-directed or consumer-directed), client age (over or under age 65), and severity. Data were collected on client demographics, condition/functional status, and supportive service experience. Outcome measures were developed in three areas: safety, unmet need, and service satisfaction. Factor analysis was used to reduce multiple outcome measures to nine dimensions. Multiple regression analysis was used to assess the effect of service model on each outcome dimension, taking into account the client-provider relationship, client demographics, and case mix. Recipients of IHSS services as of mid-1996 were interviewed by telephone. The survey was conducted in late 1996 and early 1997. On various outcomes, recipients in the consumer-directed model report more positive outcomes than those in the agency model, or they report no difference. Statistically significant differences emerge on recipient safety, unmet needs, and service satisfaction. A family member present as a paid provider is also associated with more positive reported outcomes within the consumer-directed model, but model differences persist even when this is taken into account. Although both models have strengths and weaknesses, from a recipient perspective the consumer-directed model is associated with more positive outcomes. Although health professionals have expressed concerns about the capacity of consumer direction to assure quality, particularly with respect to safety, meeting unmet

  6. MODEL OF PROVIDING WITH DEVELOPMENT STRATEGY FOR INFORMATION TECHNOLOGIES IN AN ORGANIZATION

    Directory of Open Access Journals (Sweden)

    A. A. Kuzkin

    2015-03-01

    Full Text Available Subject of research. The paper presents research and instructional tools for assessment of providing with the development strategy for information technologies in an organization. Method. The corresponding assessment model is developed which takes into consideration IT-processes equilibrium according to selected efficiency factors of information technologies application. Basic results. The model peculiarity resides in applying neuro-fuzzy approximators where the conclusion is drawn upon fuzzy logic, and membership functions are adjusted through the use of neural networks. For the adequacy testing of the suggested model, due diligence result analysis has been carried out for the IT-strategy executed in the “Navigator” group of companies at the stage of implementation and support of new technologies and production methods. Data visualization with a circle diagram is applied for the comparative evaluation of the analysis results. The chosen model adequacy is proved by the agreement between predictive assessments for IT-strategy performance targets derived by means of the fuzzy cognitive model over 12 months planning horizon and the real values of these targets upon the expiry of the given planning term. Practical significance. The developed model application gives the possibility to solve the problem of sustainability assessment for the process of providing the required IT-strategy realization level based upon the fuzzy cognitive map analysis and to reveal IT-objectives changing tendencies for an organization over the stated planning interval.

  7. Influence Learning Model ARIAS and ARIAS Combined Concept maps to Critical Thinking Skills, Cognitive, and Affective

    Directory of Open Access Journals (Sweden)

    Ismail Ismail

    2014-06-01

    Full Text Available Pengaruh Model Pembelajaran ARIAS dan ARIAS Dipadu Peta Konsep terhadap Kemampuan Berpikir Kritis, Kognitif, dan Afektif Abstract: The learning model Assurance, Relevance, Interest, Assessment, and Satisfaction (ARIAS combined concept maps can enhance critical thinking skills, cognitive, and affective. The study aims to examine the effect of learning model ARIAS, combined ARIAS concept maps and concept maps on the ability of critical thinking, cognitive, and affective. The research data were collected through the test description and observation sheet. The result showed that the average value of critical thinking skills, cognitive and affective for group learning model combined ARIAS Concept maps very well classified category, class learning ARIAS treatment, and treatment classes Concept maps including both categories. Key Words: influence, ARIAS, concept maps, critical thinking, cognitive, and affective Abstrak: Model pembelajaran Assurance, Relevance, Interest, Assessment, dan Satisfaction (ARIAS  dipadu peta konsep dapat meningkatkan kemampuan berpikir kritis, kognitif, dan afektif. Penelitian bertujuan untuk menguji pengaruh model pembelajaran ARIAS, ARIAS dipadu peta konsep, dan peta konsep terhadap kemampuan berpikir kritis, kognitif, dan afektif. Data penelitian dikumpulkan melalui tes uraian dan lembar observasi. Hasil analisis data menunjukkan bahwa nilai rata-rata kemampuan berpikir kritis, kognitif dan afektif untuk kelompok model pembelajaran ARIAS dipadu Peta Konsep tergolong kategori sangat baik, kelas perlakuan pembelajaran ARIAS, dan kelas perlakuan Peta Konsep termasuk kategori baik. Kata kunci: pengaruh, ARIAS, peta konsep, berpikir kritis, kognitif, afektif

  8. Simulation model for transcervical laryngeal injection providing real-time feedback.

    Science.gov (United States)

    Ainsworth, Tiffiny A; Kobler, James B; Loan, Gregory J; Burns, James A

    2014-12-01

    This study aimed to develop and evaluate a model for teaching transcervical laryngeal injections. A 3-dimensional printer was used to create a laryngotracheal framework based on de-identified computed tomography images of a human larynx. The arytenoid cartilages and intrinsic laryngeal musculature were created in silicone from clay casts and thermoplastic molds. The thyroarytenoid (TA) muscle was created with electrically conductive silicone using metallic filaments embedded in silicone. Wires connected TA muscles to an electrical circuit incorporating a cell phone and speaker. A needle electrode completed the circuit when inserted in the TA during simulated injection, providing real-time feedback of successful needle placement by producing an audible sound. Face validation by the senior author confirmed appropriate tactile feedback and anatomical realism. Otolaryngologists pilot tested the model and completed presimulation and postsimulation questionnaires. The high-fidelity simulation model provided tactile and audio feedback during needle placement, simulating transcervical vocal fold injections. Otolaryngology residents demonstrated higher comfort levels with transcervical thyroarytenoid injection on postsimulation questionnaires. This is the first study to describe a simulator for developing transcervical vocal fold injection skills. The model provides real-time tactile and auditory feedback that aids in skill acquisition. Otolaryngologists reported increased confidence with transcervical injection after using the simulator. © The Author(s) 2014.

  9. Fast and accurate Bayesian model criticism and conflict diagnostics using R-INLA

    KAUST Repository

    Ferkingstad, Egil

    2017-10-16

    Bayesian hierarchical models are increasingly popular for realistic modelling and analysis of complex data. This trend is accompanied by the need for flexible, general and computationally efficient methods for model criticism and conflict detection. Usually, a Bayesian hierarchical model incorporates a grouping of the individual data points, as, for example, with individuals in repeated measurement data. In such cases, the following question arises: Are any of the groups “outliers,” or in conflict with the remaining groups? Existing general approaches aiming to answer such questions tend to be extremely computationally demanding when model fitting is based on Markov chain Monte Carlo. We show how group-level model criticism and conflict detection can be carried out quickly and accurately through integrated nested Laplace approximations (INLA). The new method is implemented as a part of the open-source R-INLA package for Bayesian computing (http://r-inla.org).

  10. Disordered cellular automaton traffic flow model: phase separated state, density waves and self organized criticality

    Science.gov (United States)

    Fourrate, K.; Loulidi, M.

    2006-01-01

    We suggest a disordered traffic flow model that captures many features of traffic flow. It is an extension of the Nagel-Schreckenberg (NaSch) stochastic cellular automata for single line vehicular traffic model. It incorporates random acceleration and deceleration terms that may be greater than one unit. Our model leads under its intrinsic dynamics, for high values of braking probability pr, to a constant flow at intermediate densities without introducing any spatial inhomogeneities. For a system of fast drivers pr→0, the model exhibits a density wave behavior that was observed in car following models with optimal velocity. The gap of the disordered model we present exhibits, for high values of pr and random deceleration, at a critical density, a power law distribution which is a hall mark of a self organized criticality phenomena.

  11. Survival data analyses in ecotoxicology: critical effect concentrations, methods and models. What should we use?

    Science.gov (United States)

    Forfait-Dubuc, Carole; Charles, Sandrine; Billoir, Elise; Delignette-Muller, Marie Laure

    2012-05-01

    In ecotoxicology, critical effect concentrations are the most common indicators to quantitatively assess risks for species exposed to contaminants. Three types of critical effect concentrations are classically used: lowest/ no observed effect concentration (LOEC/NOEC), LC( x) (x% lethal concentration) and NEC (no effect concentration). In this article, for each of these three types of critical effect concentration, we compared methods or models used for their estimation and proposed one as the most appropriate. We then compared these critical effect concentrations to each other. For that, we used nine survival data sets corresponding to D. magna exposition to nine different contaminants, for which the time-course of the response was monitored. Our results showed that: (i) LOEC/NOEC values at day 21 were method-dependent, and that the Cochran-Armitage test with a step-down procedure appeared to be the most protective for the environment; (ii) all tested concentration-response models we compared gave close values of LC50 at day 21, nevertheless the Weibull model had the lowest global mean deviance; (iii) a simple threshold NEC-model both concentration and time dependent more completely described whole data (i.e. all timepoints) and enabled a precise estimation of the NEC. We then compared the three critical effect concentrations and argued that the use of the NEC might be a good option for environmental risk assessment.

  12. Military service member and veteran reintegration: A critical review and adapted ecological model.

    Science.gov (United States)

    Elnitsky, Christine A; Blevins, Cara L; Fisher, Michael P; Magruder, Kathryn

    2017-01-01

    Returning military service members and veterans (MSMVs) experience a wide range of stress-related disorders in addition to social and occupational difficulties when reintegrating to the community. Facilitating reintegration of MSMVs following deployment is a societal priority. With an objective of identifying challenges and facilitators for reintegration of MSMVs of the current war era, we critically review and identify gaps in the literature. We searched 8 electronic databases and identified 1,764 articles. Screening of abstracts and full-text review based on our inclusion/exclusion criteria, yielded 186 articles for review. Two investigators evaluating relevant articles independently found a lack of clear definition or comprehensive theorizing about MSMV reintegration. To address these gaps, we linked the findings from the literature to provide a unified definition of reintegration and adapted the social ecological systems theory to guide research and practice aimed at MSMV reintegration. Furthermore, we identified individual, interpersonal, community, and societal challenges related to reintegration. The 186 studies published from 2001 (the start of the current war era) to 2015 included 6 experimental studies or clinical trials. Most studies do not adequately account for context or more than a narrow set of potential influences on MSMV reintegration. Little evidence was found that evaluated interventions for health conditions, rehabilitation, and employment, or effective models of integrated delivery systems. We recommend an ecological model of MSMV reintegration to advance research and practice processes and outcomes at 4 levels (individual, interpersonal, organizational, and societal). (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  13. Benchmark models and experimental data for a U(20) polyethylene-moderated critical system

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, Larry [Babcock & Wilcox Nuclear Operations Group Inc.; Busch, Robert D. [University of New Mexico, Albuquerque; Bowen, Douglas G [ORNL

    2015-01-01

    This work involves the analysis of recent experiments performed on the Aerojet General Nucleonics (AGN)-201M (AGN) polyethylene-moderated research reactor at the University of New Mexico (UNM). The experiments include 36 delayed critical (DC) configurations and 11 positive-period and rod-drop measurements (transient sequences). The Even Parity Neutron Transport (EVENT) radiation transport code was chosen to analyze these steady state and time-dependent experimental configurations. The UNM AGN specifications provided in a benchmark calculation report (2007) were used to initiate AGN EVENT model development and to test the EVENT AGN calculation methodology. The results of the EVENT DC experimental analyses compared well with the experimental data; the average AGN EVENT calculation bias in the keff is –0.0048% for the Legrendre Flux Expansion Order of 11 (P11) cases and +0.0119% for the P13 cases. The EVENT transient analysis also compared well with the AGN experimental data with respect to predicting the reactor period and control rod worth values. This paper discusses the benchmark models used, the recent experimental configurations, and the EVENT experimental analysis.

  14. Critical Thinking Skills of Students through Mathematics Learning with ASSURE Model Assisted by Software Autograph

    Science.gov (United States)

    Kristianti, Y.; Prabawanto, S.; Suhendra, S.

    2017-09-01

    This study aims to examine the ability of critical thinking and students who attain learning mathematics with learning model ASSURE assisted Autograph software. The design of this study was experimental group with pre-test and post-test control group. The experimental group obtained a mathematics learning with ASSURE-assisted model Autograph software and the control group acquired the mathematics learning with the conventional model. The data are obtained from the research results through critical thinking skills tests. This research was conducted at junior high school level with research population in one of junior high school student in Subang Regency of Lesson Year 2016/2017 and research sample of class VIII student in one of junior high school in Subang Regency for 2 classes. Analysis of research data is administered quantitatively. Quantitative data analysis was performed on the normalized gain level between the two sample groups using a one-way anova test. The results show that mathematics learning with ASSURE assisted model Autograph software can improve the critical thinking ability of junior high school students. Mathematical learning using ASSURE-assisted model Autograph software is significantly better in improving the critical thinking skills of junior high school students compared with conventional models.

  15. A simple model for the earthquake cycle combining self-organized complexity with critical point behavior

    Directory of Open Access Journals (Sweden)

    W. I. Newman

    2002-01-01

    Full Text Available We have studied a hybrid model combining the forest-fire model with the site-percolation model in order to better understand the earthquake cycle. We consider a square array of sites. At each time step, a "tree" is dropped on a randomly chosen site and is planted if the site is unoccupied. When a cluster of "trees" spans the site (a percolating cluster, all the trees in the cluster are removed ("burned" in a "fire." The removal of the cluster is analogous to a characteristic earthquake and planting "trees" is analogous to increasing the regional stress. The clusters are analogous to the metastable regions of a fault over which an earthquake rupture can propagate once triggered. We find that the frequency-area statistics of the metastable regions are power-law with a negative exponent of two (as in the forest-fire model. This is analogous to the Gutenberg-Richter distribution of seismicity. This "self-organized critical behavior" can be explained in terms of an inverse cascade of clusters. Small clusters of "trees" coalesce to form larger clusters. Individual trees move from small to larger clusters until they are destroyed. This inverse cascade of clusters is self-similar and the power-law distribution of cluster sizes has been shown to have an exponent of two. We have quantified the forecasting of the spanning fires using error diagrams. The assumption that "fires" (earthquakes are quasi-periodic has moderate predictability. The density of trees gives an improved degree of predictability, while the size of the largest cluster of trees provides a substantial improvement in forecasting a "fire."

  16. Milestones of critical thinking: a developmental model for medicine and nursing.

    Science.gov (United States)

    Papp, Klara K; Huang, Grace C; Lauzon Clabo, Laurie M; Delva, Dianne; Fischer, Melissa; Konopasek, Lyuba; Schwartzstein, Richard M; Gusic, Maryellen

    2014-05-01

    Critical thinking is essential to a health professional's competence to assess, diagnose, and care for patients. Defined as the ability to apply higher-order cognitive skills (conceptualization, analysis, evaluation) and the disposition to be deliberate about thinking (being open-minded or intellectually honest) that lead to action that is logical and appropriate, critical thinking represents a "meta-competency" that transcends other knowledge, skills, abilities, and behaviors required in health care professions. Despite its importance, the developmental stages of critical thinking have not been delineated for nurses and physicians. As part of a task force of educators who considered different developmental stage theories, the authors have iteratively refined and proposed milestones in critical thinking. The attributes associated with unreflective, beginning, practicing, advanced, accomplished, and challenged critical thinkers are conceived as independent of an individual's level of training. Depending on circumstances and environmental factors, even the most experienced clinician may demonstrate attributes associated with a challenged thinker. The authors use the illustrative case of a patient with abdominal pain to demonstrate how critical thinking may manifest in learners at different stages of development, analyzing how the learner at each stage applies information obtained in the patient interaction to arrive at a differential diagnosis and plan for evaluation. The authors share important considerations and provide this work as a foundation for the development of effective approaches to teaching and promoting critical thinking and to establishing expectations for learners in this essential meta-competency.

  17. Testing a model for the critical degree of saturation at freezing of porous building materials

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1996-01-01

    -thaw without de-icing salts. The model has been tested on various concretes without air-entrainment and on brick tiles with different porosities. Results agree qualitatively with values of the critical degree of saturation determined by measuring resonance frequencies and length change of sealed specimens...... during freezing. The reliability and usefulness of the model are discussed, e.g. in relation to air-entrained materials and in relation to the description of the pore structure.Keywords: Brick tile, concrete, critical degree of saturation, eigenstrain, fracture mechanics, frost resistance, pore structure...

  18. Modelling transient 3D multi-phase criticality in fluidised granular materials - the FETCH code

    International Nuclear Information System (INIS)

    Pain, C.C.; Gomes, J.L.M.A.; Eaton, M.D.; Ziver, A.K.; Umpleby, A.P.; Oliveira, C.R.E. de; Goddard, A.J.H.

    2003-01-01

    The development and application of a generic model for modelling criticality in fluidised granular materials is described within the Finite Element Transient Criticality (FETCH) code - which models criticality transients in spatial and temporal detail from fundamental principles, as far as is currently possible. The neutronics model in FETCH solves the neutron transport in full phase space with a spherical harmonics angle of travel representation, multi-group in neutron energy, Crank Nicholson based in time stepping, and finite elements in space. The fluids representation coupled with the neutronics model is a two-fluid-granular-temperature model, also finite element fased. A separate fluid is used to represent the liquid/vapour gas and the solid fuel particle phases, respectively. Particle-particle, particle-wall interactions are modelled using a kinetic theory approach on an analogy between the motion of gas molecules subject to binary collisions and granular flows. This model has been extensively validated by comparison with fluidised bed experimental results. Gas-fluidised beds involve particles that are often extremely agitated (measured by granular temperature) and can thus be viewed as a particularly demanding application of the two-fluid model. Liquid fluidised systems are of criticality interest, but these can become demanding with the production of gases (e.g. radiolytic and water vapour) and large fluid/particle velocities in energetic transients. We present results from a test transient model in which fissile material ( 239 Pu) is presented as spherical granules subsiding in water, located in a tank initially at constant temperature and at two alternative over-pressures in order to verify the theoretical model implemented in FETCH. (author)

  19. Integrating critical thinking and evidence-based dentistry across a four-year dental curriculum: a model for independent learning.

    Science.gov (United States)

    Marshall, Teresa A; Straub-Morarend, Cheryl L; Handoo, Nidhi; Solow, Catherine M; Cunningham-Ford, Marsha A; Finkelstein, Michael W

    2014-03-01

    Introducing critical thinking and evidence-based dentistry (EBD) content into an established dental curriculum can be a difficult and challenging process. Over the past three years, the University of Iowa College of Dentistry has developed and implemented a progressive four-year integrated critical thinking and EBD curriculum. The objective of this article is to describe the development and implementation process to make it available as a model for other dental schools contemplating introduction of critical thinking and EBD into their curricula. The newly designed curriculum built upon an existing problem-based learning foundation, which introduces critical thinking and the scientific literature in the D1 year, in order to expose students to the rationale and resources for practicing EBD in the D2 and D3 years and provide opportunities to practice critical thinking and apply the EBD five-step process in the D2, D3, and D4 years. All curricular content is online, and D3 and D4 EBD activities are integrated within existing clinical responsibilities. The curricular content, student resources, and student activities are described.

  20. Rat tibial osteotomy model providing a range of normal to impaired healing.

    Science.gov (United States)

    Miles, Joan D; Weinhold, Paul; Brimmo, Olubusola; Dahners, Laurence

    2011-01-01

    The purpose of this study was to develop an inexpensive and easily implemented rat tibial osteotomy model capable of producing a range of healing outcomes. A saw blade was used to create a transverse osteotomy of the tibia in 89 Sprague-Dawley rats. A 0.89 mm diameter stainless steel wire was then inserted as an intramedullary nail to stabilize the fracture. To impair healing, 1, 2, or 3 mm cylindrical polyetheretherketone (PEEK) spacer beads were threaded onto the wires, between the bone ends. Fracture healing was evaluated radiographically, biomechanically, and histologically at 5 weeks. Means were compared for statistical differences by one-way ANOVA and Holm-Sidak multiple comparison testing. The mean number of "cortices bridged" for the no spacer group was 3.4 (SD ± 0.8), which was significantly greater than in the 1 mm (2.3 ± 1.4), 2 mm (0.8 ± 0.7), and 3 mm (0.3 ± 0.4) groups (p < 0.003). Biomechanical results correlated with radiographic findings, with an ultimate torque of 172 ± 53, 137 ± 41, 90 ± 38, and 24 ± 23 N/mm with a 0, 1, 2, or 3 mm defect, respectively. In conclusion, we have demonstrated that this inexpensive, technically straightforward model can be used to create a range of outcomes from normal healing to impaired healing, to nonunions. This model may be useful for testing new therapeutic strategies to promote fracture healing, materials thought to be able to heal critical-sized defects, or evaluating agents suspected of impairing healing. Copyright © 2010 Orthopaedic Research Society.

  1. Developing Critical Thinking through Leadership Education

    Science.gov (United States)

    Jenkins, Daniel M.; Andenoro, Anthony C.

    2016-01-01

    This chapter provides the critical leadership logic model as a tool to help educators develop leadership-learning opportunities. This proactive logic model includes curricular and co-curricular educational experiences to ensure critical thinking through leadership education.

  2. Wind farms providing secondary frequency regulation: Evaluating the performance of model-based receding horizon control

    International Nuclear Information System (INIS)

    Shapiro, Carl R.; Meneveau, Charles; Gayme, Dennice F.; Meyers, Johan

    2016-01-01

    We investigate the use of wind farms to provide secondary frequency regulation for a power grid. Our approach uses model-based receding horizon control of a wind farm that is tested using a large eddy simulation (LES) framework. In order to enable real-time implementation, the control actions are computed based on a time-varying one-dimensional wake model. This model describes wake advection and interactions, both of which play an important role in wind farm power production. This controller is implemented in an LES model of an 84-turbine wind farm represented by actuator disk turbine models. Differences between the velocities at each turbine predicted by the wake model and measured in LES are used for closed-loop feedback. The controller is tested on two types of regulation signals, “RegA” and “RegD”, obtained from PJM, an independent system operator in the eastern United States. Composite performance scores, which are used by PJM to qualify plants for regulation, are used to evaluate the performance of the controlled wind farm. Our results demonstrate that the controlled wind farm consistently performs well, passing the qualification threshold for all fastacting RegD signals. For the RegA signal, which changes over slower time scales, the controlled wind farm's average performance surpasses the threshold, but further work is needed to enable the controlled system to achieve qualifying performance all of the time. (paper)

  3. Analytical model of the critical current of a bent Nb3Sn strand

    International Nuclear Information System (INIS)

    Koizumi, Norikiyo; Murakami, Haruyuki; Hemmi, Tsutomu; Nakajima, Hideo

    2011-01-01

    The critical current performance of a large Nb 3 Sn cable-in-conduit conductor (CICC) was degraded by periodic bending of strands due to a large transverse electromagnetic force. The degradation of each strand due to this bending should be evaluated in calculations of the critical current of a CICC, but a suitable model has not been developed yet. Therefore, the authors have developed a new analytical model which takes into account plastic deformation of copper and bronze and filament breakage. The calculated results were compared with test results for uniformly bent Nb 3 Sn bronze-route strands. The calculated results assuming a high transverse resistance model (HTRM) show good agreement with the test results, a finding which confirms the validity of the model. Because of a much shorter calculation time than for numerical simulation, the developed model seems much more practical for use in calculating the critical current performance of a Nb 3 Sn CICC. In addition, simulation results show that since the neutral axis of a bent strand shifts to the compressive side due to plastic deformation of the copper and bronze, and/or filament breakage, the strand is elongated by bending. This elongation may enhance the strand's critical current performance. Moreover, the calculated results indicate that the dependence of the critical current on the bending strain is affected by the bending history if the strand is excessively bent, especially when filaments are broken. In a real magnet, since a strand in a CICC is normally subject to the maximum electromagnetic force prior to an evaluation of its performance at a lower electromagnetic force, the effect of over-bending should be taken into account in calculations of its critical current performance, especially when filament breakage occurs.

  4. Biomass transformation webs provide a unified approach to consumer-resource modelling.

    Science.gov (United States)

    Getz, Wayne M

    2011-02-01

    An approach to modelling food web biomass flows among live and dead compartments within and among species is formulated using metaphysiological principles that characterise population growth in terms of basal metabolism, feeding, senescence and exploitation. This leads to a unified approach to modelling interactions among plants, herbivores, carnivores, scavengers, parasites and their resources. Also, dichotomising sessile miners from mobile gatherers of resources, with relevance to feeding and starvation time scales, suggests a new classification scheme involving 10 primary categories of consumer types. These types, in various combinations, rigorously distinguish scavenger from parasite, herbivory from phytophagy and detritivore from decomposer. Application of the approach to particular consumer-resource interactions is demonstrated, culminating in the construction of an anthrax-centred food web model, with parameters applicable to Etosha National Park, Namibia, where deaths of elephants and zebra from the bacterial pathogen, Bacillus anthracis, provide significant subsidies to jackals, vultures and other scavengers. © 2010 Blackwell Publishing Ltd/CNRS.

  5. Biomass transformation webs provide a unified approach to consumer–resource modelling

    Science.gov (United States)

    Getz, Wayne M.

    2011-01-01

    An approach to modelling food web biomass flows among live and dead compartments within and among species is formulated using metaphysiological principles that characterise population growth in terms of basal metabolism, feeding, senescence and exploitation. This leads to a unified approach to modelling interactions among plants, herbivores, carnivores, scavengers, parasites and their resources. Also, dichotomising sessile miners from mobile gatherers of resources, with relevance to feeding and starvation time scales, suggests a new classification scheme involving 10 primary categories of consumer types. These types, in various combinations, rigorously distinguish scavenger from parasite, herbivory from phytophagy and detritivore from decomposer. Application of the approach to particular consumer–resource interactions is demonstrated, culminating in the construction of an anthrax-centred food web model, with parameters applicable to Etosha National Park, Namibia, where deaths of elephants and zebra from the bacterial pathogen, Bacillus anthracis, provide significant subsidies to jackals, vultures and other scavengers. PMID:21199247

  6. Modeling Key Drivers of Cholera Transmission Dynamics Provides New Perspectives for Parasitology.

    Science.gov (United States)

    Rinaldo, Andrea; Bertuzzo, Enrico; Blokesch, Melanie; Mari, Lorenzo; Gatto, Marino

    2017-08-01

    Hydroclimatological and anthropogenic factors are key drivers of waterborne disease transmission. Information on human settlements and host mobility on waterways along which pathogens and hosts disperse, and relevant hydroclimatological processes, can be acquired remotely and included in spatially explicit mathematical models of disease transmission. In the case of epidemic cholera, such models allowed the description of complex disease patterns and provided insight into the course of ongoing epidemics. The inclusion of spatial information in models of disease transmission can aid in emergency management and the assessment of alternative interventions. Here, we review the study of drivers of transmission via spatially explicit approaches and argue that, because many parasitic waterborne diseases share the same drivers as cholera, similar principles may apply. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. A Complex of Business Process Management Models for a Service-Providing IT Company

    Directory of Open Access Journals (Sweden)

    Yatsenko Roman M.

    2017-10-01

    Full Text Available The article presents an analysis of a complex of business process management models that are designed to improve the performance of service-providing IT companies. This class of enterprises was selected because of their significant contribution to the Ukrainian economy: third place in the structure of exports, significant budget revenues, high development dynamics, and prospects in the global marketplace. The selected complex of models is designed as a sequence of stages that must be accomplished in order to optimize business processes. The first stage is an analysis of the nature of the process approach, approaches to strategic management, and the characteristics of service-providing IT companies. The second stage is to build the formal and hierarchical models to define the characteristics of the business processes and their structure, respectively. The third stage is to evaluate individual business processes (information model and the entire business process system (multi-level assessment of business processes. The fourth stage is to optimize the business processes at each level: strategic, tactical and operational. The fifth stage is to restructure the business processes after optimization. The sixth (final stage is to analyze the efficiency of the restructured system of business processes.

  8. Pharmacists providing care in the outpatient setting through telemedicine models: a narrative review

    Directory of Open Access Journals (Sweden)

    Littauer SL

    2017-12-01

    Full Text Available Telemedicine refers to the delivery of clinical services using technology that allows two-way, real time, interactive communication between the patient and the clinician at a distant site. Commonly, telemedicine is used to improve access to general and specialty care for patients in rural areas. This review aims to provide an overview of existing telemedicine models involving the delivery of care by pharmacists via telemedicine (including telemonitoring and video, but excluding follow-up telephone calls and to highlight the main areas of chronic-disease management where these models have been applied. Studies within the areas of hypertension, diabetes, asthma, anticoagulation and depression were identified, but only two randomized controlled trials with adequate sample size demonstrating the positive impact of telemonitoring combined with pharmacist care in hypertension were identified. The evidence for the impact of pharmacist-based telemedicine models is sparse and weak, with the studies conducted presenting serious threats to internal and external validity. Therefore, no definitive conclusions about the impact of pharmacist-led telemedicine models can be made at this time. In the Unites States, the increasing shortage of primary care providers and specialists represents an opportunity for pharmacists to assume a more prominent role managing patients with chronic disease in the ambulatory care setting. However, lack of reimbursement may pose a barrier to the provision of care by pharmacists using telemedicine.

  9. Agent-based organizational modelling for analysis of safety culture at an air navigation service provider

    International Nuclear Information System (INIS)

    Stroeve, Sybert H.; Sharpanskykh, Alexei; Kirwan, Barry

    2011-01-01

    Assessment of safety culture is done predominantly by questionnaire-based studies, which tend to reveal attitudes on immaterial characteristics (values, beliefs, norms). There is a need for a better understanding of the implications of the material aspects of an organization (structures, processes, etc.) for safety culture and their interactions with the immaterial characteristics. This paper presents a new agent-based organizational modelling approach for integrated and systematic evaluation of material and immaterial characteristics of socio-technical organizations in safety culture analysis. It uniquely considers both the formal organization and the value- and belief-driven behaviour of individuals in the organization. Results are presented of a model for safety occurrence reporting at an air navigation service provider. Model predictions consistent with questionnaire-based results are achieved. A sensitivity analysis provides insight in organizational factors that strongly influence safety culture indicators. The modelling approach can be used in combination with attitude-focused safety culture research, towards an integrated evaluation of material and immaterial characteristics of socio-technical organizations. By using this approach an organization is able to gain a deeper understanding of causes of diverse problems and inefficiencies both in the formal organization and in the behaviour of organizational agents, and to systematically identify and evaluate improvement options.

  10. Training of Students’ Critical Thinking Skills through the implementation of a Modified Free Inquiry Model

    Science.gov (United States)

    Hadi, S. A.; Susantini, E.; Agustini, R.

    2018-01-01

    This research aimed at training students’ critical thinking skills through the implementation of a modified free inquiry learning model. The subjects of this research were 21 students of Mathematics Semester II. Using One-Group Pretest-Posttest Design, the data were analyzed descriptively using N-gain indicator. The results indicate that the modified free inquiry learning model was effective to train students’ critical thinking skills. The increase in the students’ critical thinking skills viewed from the value of N-Gain has a range of values with the categories of medium and high with a score between 0,25-0,95. Overall, the change in N-Gain score of each student and each indicator of critical thinking skills is as increasing with a moderate category. The increase of N-Gain value is resulted from the fact that the students were directly involved in organizing their learning process. These criteria indicate that the modified free inquiry learning model can be used to train students’ critical thinking skills on photosynthesis and cellular respiration materials. The results of this research are expected to be nationally implemented to familiarize students with andragogy learning style which places the students as the subjects of learning.

  11. Probabilistic models for neural populations that naturally capture global coupling and criticality.

    Science.gov (United States)

    Humplik, Jan; Tkačik, Gašper

    2017-09-01

    Advances in multi-unit recordings pave the way for statistical modeling of activity patterns in large neural populations. Recent studies have shown that the summed activity of all neurons strongly shapes the population response. A separate recent finding has been that neural populations also exhibit criticality, an anomalously large dynamic range for the probabilities of different population activity patterns. Motivated by these two observations, we introduce a class of probabilistic models which takes into account the prior knowledge that the neural population could be globally coupled and close to critical. These models consist of an energy function which parametrizes interactions between small groups of neurons, and an arbitrary positive, strictly increasing, and twice differentiable function which maps the energy of a population pattern to its probability. We show that: 1) augmenting a pairwise Ising model with a nonlinearity yields an accurate description of the activity of retinal ganglion cells which outperforms previous models based on the summed activity of neurons; 2) prior knowledge that the population is critical translates to prior expectations about the shape of the nonlinearity; 3) the nonlinearity admits an interpretation in terms of a continuous latent variable globally coupling the system whose distribution we can infer from data. Our method is independent of the underlying system's state space; hence, it can be applied to other systems such as natural scenes or amino acid sequences of proteins which are also known to exhibit criticality.

  12. Modeling fMRI signals can provide insights into neural processing in the cerebral cortex.

    Science.gov (United States)

    Vanni, Simo; Sharifian, Fariba; Heikkinen, Hanna; Vigário, Ricardo

    2015-08-01

    Every stimulus or task activates multiple areas in the mammalian cortex. These distributed activations can be measured with functional magnetic resonance imaging (fMRI), which has the best spatial resolution among the noninvasive brain imaging methods. Unfortunately, the relationship between the fMRI activations and distributed cortical processing has remained unclear, both because the coupling between neural and fMRI activations has remained poorly understood and because fMRI voxels are too large to directly sense the local neural events. To get an idea of the local processing given the macroscopic data, we need models to simulate the neural activity and to provide output that can be compared with fMRI data. Such models can describe neural mechanisms as mathematical functions between input and output in a specific system, with little correspondence to physiological mechanisms. Alternatively, models can be biomimetic, including biological details with straightforward correspondence to experimental data. After careful balancing between complexity, computational efficiency, and realism, a biomimetic simulation should be able to provide insight into how biological structures or functions contribute to actual data processing as well as to promote theory-driven neuroscience experiments. This review analyzes the requirements for validating system-level computational models with fMRI. In particular, we study mesoscopic biomimetic models, which include a limited set of details from real-life networks and enable system-level simulations of neural mass action. In addition, we discuss how recent developments in neurophysiology and biophysics may significantly advance the modelling of fMRI signals. Copyright © 2015 the American Physiological Society.

  13. Modeling the Self-organized Critical Behavior of the Plasma Sheet Reconnection Dynamics

    Science.gov (United States)

    Klimas, Alex; Uritsky, Vadim; Baker, Daniel

    2006-01-01

    Analyses of Polar UVI auroral image data reviewed in our other presentation at this meeting (V. Uritsky, A. Klimas) show that bright night-side high-latitude UV emissions exhibit so many of the key properties of systems in self-organized criticality (SOC) that an alternate interpretation has become virtually impossible. It is now necessary to find and model the source of this behavior. We note that the most common models of self-organized criticality are numerical sandpiles. These are, at root, models that govern the transport of some quantity from a region where it is loaded to another where it is unloaded. Transport is enabled by the excitation of a local threshold instability; it is intermittent and bursty, and it exhibits a number of scale-free statistical properties. Searching for a system in the magnetosphere that is analogous and that, in addition, is known to produce auroral signatures, we focus on the reconnection dynamics of the plasma sheet. In our previous work, a driven reconnection model has been constructed and has been under study. The transport of electromagnetic (primarily magnetic) energy carried by the Poynting flux into the reconnection region of the model has been examined. All of the analysis techniques, and more, that have been applied to the auroral image data have also been applied to this Poynting flux. Here, we report new results showing that this model also exhibits so many of the key properties of systems in self-organized criticality that an alternate interpretation is implausible. Further, we find a strong correlation between these key properties of the model and those of the auroral UV emissions. We suggest that, in general, the driven reconnection model is an important step toward a realistic plasma physical model of self-organized criticality and we conclude, more specifically, that it is also a step in the right direction toward modeling the multiscale reconnection dynamics of the magnetotail.

  14. Modeling the Self-organized Critical Behavior of Earth's Plasma Sheet Reconnection Dynamics

    Science.gov (United States)

    Klimas, Alexander J.

    2006-01-01

    Analyses of Polar UVI auroral image data show that bright night-side high-latitude W emissions exhibit so many of the key properties of systems in self-organized criticality that an alternate interpretation has become virtually impossible. These analyses will be reviewed. It is now necessary to find and model the source of this behavior. We note that the most common models of self-organized criticality are numerical sandpiles. These are, at root, models that govern the transport of some quantity from a region where it is loaded to another where it is unloaded. Transport is enabled by the excitation of a local threshold instability; it is intermittent and bursty, and it exhibits a number of scale-free statistical properties. Searching for a system in the magnetosphere that is analogous and that, in addition, is known to produce auroral signatures, we focus on the reconnection dynamics of the magnetotail plasma sheet. In our previous work, a driven reconnection model has been constructed and has been under study. The transport of electromagnetic (primarily magnetic) energy carried by the Poynting flux into the reconnection region of the model has been examined. All of the analysis techniques (and more) that have been applied to the auroral image data have also been applied to this Poynting flux. New results will be presented showing that this model also exhibits so many of the key properties of systems in self-organized criticality that an alternate interpretation is implausible. A strong correlation between these key properties of the model and those of the auroral UV emissions will be demonstrated. We suggest that, in general, the driven reconnection model is an important step toward a realistic plasma physical model of self-organized criticality and we conclude, more specifically, that it is also a step in the right direction toward modeling the multiscale reconnection dynamics of the magnetotail.

  15. Providing critical laboratory results on time, every time to help reduce emergency department length of stay: how our laboratory achieved a Six Sigma level of performance.

    Science.gov (United States)

    Blick, Kenneth E

    2013-08-01

    To develop a fully automated core laboratory, handling samples on a "first in, first out" real-time basis with Lean/Six Sigma management tools. Our primary goal was to provide services to critical care areas, eliminating turnaround time outlier percentage (TAT-OP) as a factor in patient length of stay (LOS). A secondary goal was to achieve a better laboratory return on investment. In 2011, we reached our primary goal when we calculated the TAT-OP distribution and found we had achieved a Six Sigma level of performance, ensuring that our laboratory service can be essentially eliminated as a factor in emergency department patient LOS. We also measured return on investment, showing a productivity improvement of 35%, keeping pace with our increased testing volume. As a result of our Lean process improvements and Six Sigma initiatives, in part through (1) strategic deployment of point-of-care testing and (2) core laboratory total automation with robotics, middleware, and expert system technology, physicians and nurses at the Oklahoma University Medical Center can more effectively deliver lifesaving health care using evidence-based protocols that depend heavily on "on time, every time" laboratory services.

  16. Strong- and Weak-Universal Critical Behaviour of a Mixed-Spin Ising Model with Triplet Interactions on the Union Jack (Centered Square) Lattice

    Science.gov (United States)

    Strečka, Jozef

    2018-01-01

    The mixed spin-1/2 and spin-S Ising model on the Union Jack (centered square) lattice with four different three-spin (triplet) interactions and the uniaxial single-ion anisotropy is exactly solved by establishing a rigorous mapping equivalence with the corresponding zero-field (symmetric) eight-vertex model on a dual square lattice. A rigorous proof of the aforementioned exact mapping equivalence is provided by two independent approaches exploiting either a graph-theoretical or spin representation of the zero-field eight-vertex model. An influence of the interaction anisotropy as well as the uniaxial single-ion anisotropy on phase transitions and critical phenomena is examined in particular. It is shown that the considered model exhibits a strong-universal critical behaviour with constant critical exponents when considering the isotropic model with four equal triplet interactions or the anisotropic model with one triplet interaction differing from the other three. The anisotropic models with two different triplet interactions, which are pairwise equal to each other, contrarily exhibit a weak-universal critical behaviour with critical exponents continuously varying with a relative strength of the triplet interactions as well as the uniaxial single-ion anisotropy. It is evidenced that the variations of critical exponents of the mixed-spin Ising models with the integer-valued spins S differ basically from their counterparts with the half-odd-integer spins S.

  17. Monte Carlo modeling provides accurate calibration factors for radionuclide activity meters

    International Nuclear Information System (INIS)

    Zagni, F.; Cicoria, G.; Lucconi, G.; Infantino, A.; Lodi, F.; Marengo, M.

    2014-01-01

    Accurate determination of calibration factors for radionuclide activity meters is crucial for quantitative studies and in the optimization step of radiation protection, as these detectors are widespread in radiopharmacy and nuclear medicine facilities. In this work we developed the Monte Carlo model of a widely used activity meter, using the Geant4 simulation toolkit. More precisely the “PENELOPE” EM physics models were employed. The model was validated by means of several certified sources, traceable to primary activity standards, and other sources locally standardized with spectrometry measurements, plus other experimental tests. Great care was taken in order to accurately reproduce the geometrical details of the gas chamber and the activity sources, each of which is different in shape and enclosed in a unique container. Both relative calibration factors and ionization current obtained with simulations were compared against experimental measurements; further tests were carried out, such as the comparison of the relative response of the chamber for a source placed at different positions. The results showed a satisfactory level of accuracy in the energy range of interest, with the discrepancies lower than 4% for all the tested parameters. This shows that an accurate Monte Carlo modeling of this type of detector is feasible using the low-energy physics models embedded in Geant4. The obtained Monte Carlo model establishes a powerful tool for first instance determination of new calibration factors for non-standard radionuclides, for custom containers, when a reference source is not available. Moreover, the model provides an experimental setup for further research and optimization with regards to materials and geometrical details of the measuring setup, such as the ionization chamber itself or the containers configuration. - Highlights: • We developed a Monte Carlo model of a radionuclide activity meter using Geant4. • The model was validated using several

  18. The nursing implications of routine provider-initiated HIV testing and counselling in sub-Saharan Africa: a critical review of new policy guidance from WHO/UNAIDS.

    Science.gov (United States)

    Evans, Catrin; Ndirangu, Eunice

    2009-05-01

    In 2007 WHO/UNAIDS issued new HIV testing guidelines recommending 'provider-initiated HIV testing and counselling' (PITC). In contrast to existing 'voluntary counselling and testing' guidelines (whereby individuals self refer for testing), the PITC guidance recommends that, in countries with generalised epidemics, all patients are routinely offered an HIV test during clinical encounters. In sub-Saharan Africa, PITC aims to dramatically increase HIV testing rates so that PITC becomes a vehicle to increase access to HIV prevention and care. Nurses in this region work on the frontlines of HIV testing but have been neglected in related policy development. To provide an overview of the PITC policy guidance and to critically consider its implications for the nursing profession in sub-Saharan Africa. Policy documents and published and unpublished research were identified from organisational websites, electronic databases and conference proceedings. PITC has generated widespread debate about whether it is the right approach in a context of HIV-related stigma and lack of human/material resources. Key concerns are whether/how informed consent, privacy and confidentiality will be upheld in overstretched health care settings, and whether appropriate post-test counselling, treatment and support can be provided. Limited available evidence suggests that health systems factors and organisational/professional culture may create obstacles to effective PITC implementation. Specific findings are that: PITC greatly increases nurses' workload and work-related stress. Nurses are generally positive about PITC, but express the need for more training and managerial support. Health system constraints (lack of staff, lack of space) mean that nurses do not always have time to provide adequate counselling. A hierarchical and didactic nursing culture affects counselling quality and the boundaries between voluntary informed consent and coercion can become rather blurred. Nurses are particularly

  19. The climate4impact platform: Providing, tailoring and facilitating climate model data access

    Science.gov (United States)

    Pagé, Christian; Pagani, Andrea; Plieger, Maarten; Som de Cerff, Wim; Mihajlovski, Andrej; de Vreede, Ernst; Spinuso, Alessandro; Hutjes, Ronald; de Jong, Fokke; Bärring, Lars; Vega, Manuel; Cofiño, Antonio; d'Anca, Alessandro; Fiore, Sandro; Kolax, Michael

    2017-04-01

    One of the main objectives of climate4impact is to provide standardized web services and tools that are reusable in other portals. These services include web processing services, web coverage services and web mapping services (WPS, WCS and WMS). Tailored portals can be targeted to specific communities and/or countries/regions while making use of those services. Easier access to climate data is very important for the climate change impact communities. To fulfill this objective, the climate4impact (http://climate4impact.eu/) web portal and services has been developed, targeting climate change impact modellers, impact and adaptation consultants, as well as other experts using climate change data. It provides to users harmonized access to climate model data through tailored services. It features static and dynamic documentation, Use Cases and best practice examples, an advanced search interface, an integrated authentication and authorization system with the Earth System Grid Federation (ESGF), a visualization interface with ADAGUC web mapping tools. In the latest version, statistical downscaling services, provided by the Santander Meteorology Group Downscaling Portal, were integrated. An innovative interface to integrate statistical downscaling services will be released in the upcoming version. The latter will be a big step in bridging the gap between climate scientists and the climate change impact communities. The climate4impact portal builds on the infrastructure of an international distributed database that has been set to disseminate the results from the global climate model results of the Coupled Model Intercomparison project Phase 5 (CMIP5). This database, the ESGF, is an international collaboration that develops, deploys and maintains software infrastructure for the management, dissemination, and analysis of climate model data. The European FP7 project IS-ENES, Infrastructure for the European Network for Earth System modelling, supports the European

  20. Work-related critical incidents in hospital-based health care providers and the risk of post-traumatic stress symptoms, anxiety, and depression: a meta-analysis

    NARCIS (Netherlands)

    de Boer, Jacoba; Lok, Anja; van 't Verlaat, Ellen; Duivenvoorden, Hugo J.; Bakker, Arnold B.; Smit, Bert J.

    2011-01-01

    This meta-analysis reviewed existing data on the impact of work-related critical incidents in hospital-based health care professionals. Work-related critical incidents may induce post-traumatic stress symptoms or even post-traumatic stress disorder (PTSD), anxiety, and depression and may negatively

  1. Capabilities of stochastic rainfall models as data providers for urban hydrology

    Science.gov (United States)

    Haberlandt, Uwe

    2017-04-01

    For planning of urban drainage systems using hydrological models, long, continuous precipitation series with high temporal resolution are needed. Since observed time series are often too short or not available everywhere, the use of synthetic precipitation is a common alternative. This contribution compares three precipitation models regarding their suitability to provide 5 minute continuous rainfall time series for a) sizing of drainage networks for urban flood protection and b) dimensioning of combined sewage systems for pollution reduction. The rainfall models are a parametric stochastic model (Haberlandt et al., 2008), a non-parametric probabilistic approach (Bárdossy, 1998) and a stochastic downscaling of dynamically simulated rainfall (Berg et al., 2013); all models are operated both as single site and multi-site generators. The models are applied with regionalised parameters assuming that there is no station at the target location. Rainfall and discharge characteristics are utilised for evaluation of the model performance. The simulation results are compared against results obtained from reference rainfall stations not used for parameter estimation. The rainfall simulations are carried out for the federal states of Baden-Württemberg and Lower Saxony in Germany and the discharge simulations for the drainage networks of the cities of Hamburg, Brunswick and Freiburg. Altogether, the results show comparable simulation performance for the three models, good capabilities for single site simulations but low skills for multi-site simulations. Remarkably, there is no significant difference in simulation performance comparing the tasks flood protection with pollution reduction, so the models are finally able to simulate both the extremes and the long term characteristics of rainfall equally well. Bárdossy, A., 1998. Generating precipitation time series using simulated annealing. Wat. Resour. Res., 34(7): 1737-1744. Berg, P., Wagner, S., Kunstmann, H., Schädler, G

  2. Influence of the Radio-Oxidation Kinetic Model on the Critical Oxided Thickness

    International Nuclear Information System (INIS)

    Dely, N

    2006-01-01

    The diffusion-controlled oxidation (also named physical effect of the dose rate) is an unavoidable phenomenon that occurs in polymers under ionising radiation in presence of oxygen. Indeed, oxygen is consumed inside the polymer consecutively to radio-oxidative processes. When oxygen molecules are consumed faster than they can diffuse inside the sample, oxidation is not homogeneous within the sample thickness. This leads to a heterogeneous oxidation profile with a minimum of oxidation at the centre of the sample. In this context, the concept of critical thickness L c has been introduced. It corresponds to the thickness for which the cumulative oxygen consumption is equal to 90 % of the oxygen consumption which would occur if the oxidation was not limited by the oxygen diffusion. Gillen and Clough have determined a practical way to estimate the value of L c from several parameters linked to the experimental conditions in the frame of the homogeneous steady?state kinetic model simplified by a relation giving the reaction constant for the recombination between the macroradicals, P degree and the peroxyl radicals, POO degree. This common assumption has the unique purpose of providing an analytical solution of the oxidation rate but is in fact unfounded. Consequently, we reconsidered the calculus, still in the frame of the homogeneous steady-state kinetic model, but without this unrealistic hypothesis on the reaction rate between P degree and POO degree. We compared the results obtained in both cases. And it appears that, exception made of the very low oxygen pressure region, L c is not significantly affected by choosing the simplified kinetic model

  3. Analytical modeling provides new insight into complex mutual coupling between surface loops at ultrahigh fields.

    Science.gov (United States)

    Avdievich, N I; Pfrommer, A; Giapitzakis, I A; Henning, A

    2017-10-01

    Ultrahigh-field (UHF) (≥7 T) transmit (Tx) human head surface loop phased arrays improve both the Tx efficiency (B 1 + /√P) and homogeneity in comparison with single-channel quadrature Tx volume coils. For multi-channel arrays, decoupling becomes one of the major problems during the design process. Further insight into the coupling between array elements and its dependence on various factors can facilitate array development. The evaluation of the entire impedance matrix Z for an array loaded with a realistic voxel model or phantom is a time-consuming procedure when performed using electromagnetic (EM) solvers. This motivates the development of an analytical model, which could provide a quick assessment of the Z-matrix. In this work, an analytical model based on dyadic Green's functions was developed and validated using an EM solver and bench measurements. The model evaluates the complex coupling, including both the electric (mutual resistance) and magnetic (mutual inductance) coupling. Validation demonstrated that the model does well to describe the coupling at lower fields (≤3 T). At UHFs, the model also performs well for a practical case of low magnetic coupling. Based on the modeling, the geometry of a 400-MHz, two-loop transceiver array was optimized, such that, by simply overlapping the loops, both the mutual inductance and the mutual resistance were compensated at the same time. As a result, excellent decoupling (below -40 dB) was obtained without any additional decoupling circuits. An overlapped array prototype was compared (signal-to-noise ratio, Tx efficiency) favorably to a gapped array, a geometry which has been utilized previously in designs of UHF Tx arrays. Copyright © 2017 John Wiley & Sons, Ltd.

  4. Providing a more complete view of ice-age palaeoclimates using model inversion and data interpolation

    Science.gov (United States)

    Cleator, Sean; Harrison, Sandy P.; Roulstone, Ian; Nichols, Nancy K.; Prentice, Iain Colin

    2017-04-01

    Site-based pollen records have been used to provide quantitative reconstructions of Last Glacial Maximum (LGM) climates, but there are too few such records to provide continuous climate fields for the evaluation of climate model simulations. Furthermore, many of the reconstructions were made using modern-analogue techniques, which do not account for the direct impact of CO2 on water-use efficiency and therefore reconstruct considerably drier conditions under low CO2 at the LGM than indicated by other sources of information. We have shown that it is possible to correct analogue-based moisture reconstructions for this effect by inverting a simple light-use efficiency model of productivity, based on the principle that the rate of water loss per unit carbon gain of a plant is the same under conditions of the true moisture, palaeotemperature and palaeo CO2 concentration as under reconstructed moisture, modern CO2 concentration and modern temperature (Prentice et al., 2016). In this study, we use data from the Bartlein el al. (2011) dataset, which provides reconstructions of one or more of six climate variables (mean annual temperature, mean temperature of the warmest and coldest months, the length of the growing seasons, mean annual precipitation, and the ratio of actual to potential evapotranspiration) at individual LGM sites. We use the SPLASH water-balance model to derive a moisture index (MI) at each site from mean annual precipitation and monthly values of sunshine fraction and average temperature, and correct this MI using the Prentice et al. (2016) inversion approach. We then use a three-dimensional variational (3D-Var) data assimilation scheme with the SPLASH model and Prentice et al. (2016) inversion approach to derive reconstructions of all six climate variables at each site, using the Bartlein et al. (2011) data set as a target. We use two alternative background climate states (or priors): modern climate derived from the CRU CL v2.0 data set (New et al., 2002

  5. Family child care home providers as role models for children: Cause for concern?

    Directory of Open Access Journals (Sweden)

    Alison Tovar

    2017-03-01

    Full Text Available Health behaviors associated with chronic disease, particularly healthy eating and regular physical activity, are important role modeling opportunities for individuals working in child care programs. Prior studies have not explored these risk factors in family child care home (FCCH providers which care for vulnerable and at-risk populations. To address this gap, we describe the socio-demographic and health risk behavior profiles in a sample of providers (n = 166 FCCH taken from baseline data of an ongoing cluster-randomized controlled intervention (2011–2016 in North Carolina. Data were collected during on-site visits where providers completed self-administered questionnaires (socio-demographics, physical activity, fruit and vegetable consumption, number of hours of sleep per night and perceived stress and had their height and weight measured. A risk score (range: 0–6; 0 no risk to 6 high risk was calculated based on how many of the following were present: not having health insurance, being overweight/obese, not meeting physical activity, fruit and vegetable, and sleep recommendations, and having high stress. Mean and frequency distributions of participant and FCCH characteristics were calculated. Close to one third (29.3% of providers reported not having health insurance. Almost all providers (89.8% were overweight or obese with approximately half not meeting guidelines for physical activity, fruit and vegetable consumption, and sleep. Over half reported a “high” stress score. The mean risk score was 3.39 (±1.2, with close to half of the providers having a risk score of 4, 5 or 6 (45.7%. These results stress the need to promote the health of these important care providers.

  6. Improving Critical Thinking Skills Using Learning Model Logan Avenue Problem Solving (LAPS)-Heuristic

    Science.gov (United States)

    Anggrianto, Desi; Churiyah, Madziatul; Arief, Mohammad

    2016-01-01

    This research was conducted in order to know the effect of Logan Avenue Problem Solving (LAPS)-Heuristic learning model towards critical thinking skills of students of class X Office Administration (APK) in SMK Negeri 1 Ngawi, East Java, Indonesia on material curve and equilibrium of demand and supply, subject Introduction to Economics and…

  7. Breakup of a Stoner model for the two-dimensional ferromagnetic quantum critical point

    Science.gov (United States)

    Dzero, M.; Gor'kov, L. P.

    2004-03-01

    Generalization of the results by A. V. Chubukov et al. [Phys. Rev. Lett. 90, 077002 (2003)] leads to the conclusion that the ferromagnetic quantum critical point cannot be described by a Stoner model because of a strong interplay between the paramagnetic fluctuations and the Cooper channel, at least in two dimensions.

  8. Study on non-universal critical behaviour in Ising model with defects

    International Nuclear Information System (INIS)

    Guimaraes, L.G.

    1986-01-01

    One-dimensional quantum analogous of two-dimensional Ising models with line and step type linear defects are studied. The phenomenological renormalization group was approached using conformal invariance for relating critical exponent N sup(*) sub(H). Aiming to obtain the Hamiltonian diagonal, Lanczos tridiagonal method was used. (H.C.K.)

  9. Reanalysis of water and carbon cycle models at a critical zone observatory

    Science.gov (United States)

    The Susquehanna Shale Hills Critical Zone Observatory (SSHCZO) is a forested, hill-slope catchment located in the temperate-climate of central Pennsylvania with an extensive network of ground-based instrumentation for model testing and development. In this paper we discuss the use of multi-state fi...

  10. Implementation of the critical points model in a SFM-FDTD code working in oblique incidence

    Energy Technology Data Exchange (ETDEWEB)

    Hamidi, M; Belkhir, A; Lamrous, O [Laboratoire de Physique et Chimie Quantique, Universite Mouloud Mammeri, Tizi-Ouzou (Algeria); Baida, F I, E-mail: omarlamrous@mail.ummto.dz [Departement d' Optique P.M. Duffieux, Institut FEMTO-ST UMR 6174 CNRS Universite de Franche-Comte, 25030 Besancon Cedex (France)

    2011-06-22

    We describe the implementation of the critical points model in a finite-difference-time-domain code working in oblique incidence and dealing with dispersive media through the split field method. Some tests are presented to validate our code in addition to an application devoted to plasmon resonance of a gold nanoparticles grating.

  11. Use of combined biogeochemical model approaches and empirical data to assess critical loads of nitrogen

    Science.gov (United States)

    Mark Fenn; Charles Driscoll; Quingtao Zhou; Leela Rao; Thomas Meixner; Edith Allen; Fengming Yuan; Timothy Sullivan

    2015-01-01

    Empirical and dynamic biogeochemical modelling are complementary approaches for determining the critical load (CL) of atmospheric nitrogen (N) or other constituent deposition that an ecosystem can tolerate without causing ecological harm. The greatest benefits are obtained when these approaches are used in combination. Confounding environmental factors can complicate...

  12. Critical behavior of entropy production and learning rate: Ising model with an oscillating field

    Science.gov (United States)

    Zhang, Yirui; Barato, Andre C.

    2016-11-01

    We study the critical behavior of the entropy production of the Ising model subject to a magnetic field that oscillates in time. The mean-field model displays a phase transition that can be either first or second-order, depending on the amplitude of the field and on the frequency of oscillation. Within this approximation the entropy production rate is shown to have a discontinuity when the transition is first-order and to be continuous, with a jump in its first derivative, if the transition is second-order. In two dimensions, we find with numerical simulations that the critical behavior of the entropy production rate is the same, independent of the frequency and amplitude of the field. Its first derivative has a logarithmic divergence at the critical point. This result is in agreement with the lack of a first-order phase transition in two dimensions. We analyze a model with a field that changes at stochastic time-intervals between two values. This model allows for an informational theoretic interpretation, with the system as a sensor that follows the external field. We calculate numerically a lower bound on the learning rate, which quantifies how much information the system obtains about the field. Its first derivative with respect to temperature is found to have a jump at the critical point.

  13. A critical study of quality parameters in health care establishment: developing an integrated quality model

    NARCIS (Netherlands)

    Azam, M.; Rahman, Z.; Talib, F.; Singh, K.J.

    2012-01-01

    PURPOSE: The purpose of this article is to identify and critically analyze healthcare establishment (HCE) quality parameters described in the literature. It aims to propose an integrated quality model that includes technical quality and associated supportive quality parameters to achieve optimum

  14. Clarifications to questions and criticisms on the Johansen-Ledoit-Sornette financial bubble model

    Science.gov (United States)

    Sornette, Didier; Woodard, Ryan; Yan, Wanfeng; Zhou, Wei-Xing

    2013-10-01

    The Johansen-Ledoit-Sornette (JLS) model of rational expectation bubbles with finite-time singular crash hazard rates has been developed to describe the dynamics of financial bubbles and crashes. It has been applied successfully to a large variety of financial bubbles in many different markets. Having been developed over a decade ago, the JLS model has been studied, analyzed, used and criticized by several researchers. Much of this discussion is helpful for advancing the research. However, several serious misconceptions seem to be present within this literature both on theoretical and empirical aspects. Several of these problems stem from the fast evolution of the literature on the JLS model and related works. In the hope of removing possible misunderstanding and of catalyzing useful future developments, we summarize these common questions and criticisms concerning the JLS model and synthesize the current state of the art and existing best practice.

  15. Model-based schedulability analysis of safety critical hard real-time Java programs

    DEFF Research Database (Denmark)

    Bøgholm, Thomas; Kragh-Hansen, Henrik; Olsen, Petur

    2008-01-01

    In this paper, we present a novel approach to schedulability analysis of Safety Critical Hard Real-Time Java programs. The approach is based on a translation of programs, written in the Safety Critical Java profile introduced in [21] for the Java Optimized Processor [18], to timed automata models...... verifiable by the Uppaal model checker [23]. Schedulability analysis is reduced to a simple reachability question, checking for deadlock freedom. Model-based schedulability analysis has been developed by Amnell et al. [2], but has so far only been applied to high level specifications, not actual...... implementations in a programming language. Experiments show that model-based schedulability analysis can result in a more accurate analysis than possible with traditional approaches, thus systems deemed non-schedulable by traditional approaches may in fact be schedulable, as detected by our analysis. Our approach...

  16. Building a scholar in writing (BSW): A model for developing students' critical writing skills.

    Science.gov (United States)

    Bailey, Annette; Zanchetta, Margareth; Velasco, Divine; Pon, Gordon; Hassan, Aafreen

    2015-11-01

    Several authors have highlighted the importance of writing in developing reflective thinking skills, transforming knowledge, communicating expressions, and filling knowledge gaps. However, difficulties with higher order processing and critical analysis affect students' ability to write critical and thoughtful essays. The Building a Scholar in Writing (BSW) model is a 6-step process of increasing intricacies in critical writing development. Development of critical writing is proposed to occur in a processed manner that transitions from presenting simple ideas (just bones) in writing, to connecting ideas (connecting bones), to formulating a thesis and connecting key components (constructing a skeleton), to supporting ideas with evidence (adding muscle), to building creativity and originality (adding essential organs), and finally, developing strong, integrated, critical arguments (adding brain). This process symbolically represents the building of a scholar. The idea of building a scholar equates to progressively giving life and meaning to a piece of writing with unique scholarly characteristics. This progression involves a transformation in awareness, thinking, and understanding, as well as advancement in students' level of critical appraisal skills. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Developing thinking skill system for modelling creative thinking and critical thinking of vocational high school student

    Science.gov (United States)

    Dewanto, W. K.; Agustianto, K.; Sari, B. E.

    2018-01-01

    Vocational students must have practical skills in accordance with the purpose of vocational school that creating the skilled graduates according to their field. Graduates of vocational education are required not just as users, but be able to create. Thus requiring critical and creative thinking skills to assist students in generating ideas, analyzing and creating a product of value. Based on this, then this research aims to develop a system to know the level of ability to think critically and creative students, that resulted students can do self-reflection in improving the ability to think critically and creatively as a supporter of practical ability. The system testing using Naïve Bayes Correlation shown an average accuracy of 93.617% in assessing the students’ critical and creative thinking ability. By using modeling with this system will be known level of students’ critical and creative thinking ability, then the output of the system is used to determine the type of innovation in the learning process to improve the critical and creative thinking skills to support the practical skills of students as skilled vocational students.

  18. An improved benchmark model for the Big Ten critical assembly - 021

    International Nuclear Information System (INIS)

    Mosteller, R.D.

    2010-01-01

    A new benchmark specification is developed for the BIG TEN uranium critical assembly. The assembly has a fast spectrum, and its core contains approximately 10 wt.% enriched uranium. Detailed specifications for the benchmark are provided, and results from the MCNP5 Monte Carlo code using a variety of nuclear-data libraries are given for this benchmark and two others. (authors)

  19. Uncertainty analysis on simple mass balance model to calculate critical loads for soil acidity

    Science.gov (United States)

    Harbin Li; Steven G. McNulty

    2007-01-01

    Simple mass balance equations (SMBE) of critical acid loads (CAL) in forest soil were developed to assess potential risks of air pollutants to ecosystems. However, to apply SMBE reliably at large scales, SMBE must be tested for adequacy and uncertainty. Our goal was to provide a detailed analysis of uncertainty in SMBE so that sound strategies for scaling up CAL...

  20. Open critical area model and extraction algorithm based on the net flow-axis

    International Nuclear Information System (INIS)

    Wang Le; Wang Jun-Ping; Gao Yan-Hong; Xu Dan; Li Bo-Bo; Liu Shi-Gang

    2013-01-01

    In the integrated circuit manufacturing process, the critical area extraction is a bottleneck to the layout optimization and the integrated circuit yield estimation. In this paper, we study the problem that the missing material defects may result in the open circuit fault. Combining the mathematical morphology theory, we present a new computation model and a novel extraction algorithm for the open critical area based on the net flow-axis. Firstly, we find the net flow-axis for different nets. Then, the net flow-edges based on the net flow-axis are obtained. Finally, we can extract the open critical area by the mathematical morphology. Compared with the existing methods, the nets need not to divide into the horizontal nets and the vertical nets, and the experimental results show that our model and algorithm can accurately extract the size of the open critical area and obtain the location information of the open circuit critical area. (interdisciplinary physics and related areas of science and technology)

  1. 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.

  2. Self-organised criticality in the evolution of a thermodynamic model of rodent thermoregulatory huddling.

    Directory of Open Access Journals (Sweden)

    Stuart P Wilson

    2017-01-01

    Full Text Available A thermodynamic model of thermoregulatory huddling interactions between endotherms is developed. The model is presented as a Monte Carlo algorithm in which animals are iteratively exchanged between groups, with a probability of exchanging groups defined in terms of the temperature of the environment and the body temperatures of the animals. The temperature-dependent exchange of animals between groups is shown to reproduce a second-order critical phase transition, i.e., a smooth switch to huddling when the environment gets colder, as measured in recent experiments. A peak in the rate at which group sizes change, referred to as pup flow, is predicted at the critical temperature of the phase transition, consistent with a thermodynamic description of huddling, and with a description of the huddle as a self-organising system. The model was subjected to a simple evolutionary procedure, by iteratively substituting the physiologies of individuals that fail to balance the costs of thermoregulation (by huddling in groups with the costs of thermogenesis (by contributing heat. The resulting tension between cooperative and competitive interactions was found to generate a phenomenon called self-organised criticality, as evidenced by the emergence of avalanches in fitness that propagate across many generations. The emergence of avalanches reveals how huddling can introduce correlations in fitness between individuals and thereby constrain evolutionary dynamics. Finally, a full agent-based model of huddling interactions is also shown to generate criticality when subjected to the same evolutionary pressures. The agent-based model is related to the Monte Carlo model in the way that a Vicsek model is related to an Ising model in statistical physics. Huddling therefore presents an opportunity to use thermodynamic theory to study an emergent adaptive animal behaviour. In more general terms, huddling is proposed as an ideal system for investigating the interaction

  3. A model realization of self-organized criticality for plasma confinement

    Science.gov (United States)

    Carreras, B. A.; Newman, D.; Lynch, V. E.; Diamond, P. H.

    1996-08-01

    A model for plasma transport near marginal stability is presented. The model is based on subcri- tical resistive pressure-gradient-driven turbulence. Three-dimensional nonlinear calculations based on this model show effective transport for subcritical mean profiles. This model exhibits some of the characteristic properties of self-organized criticality. Perturbative transport techniques are used to elucidate the transport properties. Propagation of positive and negative pulses is studied. The observed results suggest a possible explanation of the apparent nonlocal effects ob- served with perturbative experiments in tokamaks.

  4. Improving Critical Thinking Skills and Students Creativity through Concept Acquisition Model

    Directory of Open Access Journals (Sweden)

    Herlina Ike Oktaviani

    2015-02-01

    Key Words: critical thinking, creative thinking, concept acquisition models   Abstrak: Tujuan penelitian ini untuk mendeskripsikan keterlaksanaan model pemerolehan konsep dalam pembelajaran biologi untuk meningkatkan kemampuan berpikir kritis dan kreatif siswa kelas VII. Melalui metode penelitian tindakan kelas dengan menggunakan instrumen pengumpulan data berupa lembar observasi kemampuan berpikir kritis dan kreatif siswa, lembar observasi keterlaksanaan pembelajaran, lembar penilaian validasi dan catatan lapangan. Hasil penelitian menunjukkan kemampuan berpikir kritis siswa kelas VII dalam Pembelajaran Biologi meningkat melalui penerapan model pemerolehan konsep.  Kata kunci: berpikir kritis, berpikir kreatif, model pemerolehan konsep

  5. A critical role for the chimpanzee model in the study of hepatitis C.

    Science.gov (United States)

    Bukh, Jens

    2004-06-01

    Chimpanzees remain the only recognized animal model for the study of hepatitis C virus (HCV). Studies performed in chimpanzees played a critical role in the discovery of HCV and are continuing to play an essential role in defining the natural history of this important human pathogen. In the absence of a reproducible cell culture system, the infectivity titer of HCV challenge pools can be determined only in chimpanzees. Recent studies in chimpanzees have provided new insight into the nature of host immune responses-particularly the intrahepatic responses-following primary and secondary experimental HCV infections. The immunogenicity and efficacy of vaccine candidates against HCV can be tested only in chimpanzees. Finally, it would not have been possible to demonstrate the infectivity of infectious clones of HCV without chimpanzees. Chimpanzees became infected when RNA transcripts from molecular clones were inoculated directly into the liver. The infection generated by such transfection did not differ significantly from that observed in animals infected intravenously with wild-type HCV. The RNA inoculated into chimpanzees originated from a single sequence, and the animals therefore had a monoclonal HCV infection. Monoclonal infection simplifies studies of HCV, because virus interaction with the host is not confounded by the quasispecies invariably present in a natural infection. It furthermore permits true homologous challenge in studies of protective immunity and in testing the efficacy of vaccine candidates. Finally, this in vivo transfection system has made it possible to test for the first time the importance of genetic elements for HCV infectivity.

  6. Critical Source Area Delineation: The representation of hydrology in effective erosion modeling.

    Science.gov (United States)

    Fowler, A.; Boll, J.; Brooks, E. S.; Boylan, R. D.

    2017-12-01

    Despite decades of conservation and millions of conservation dollars, nonpoint source sediment loading associated with agricultural disturbance continues to be a significant problem in many parts of the world. Local and national conservation organizations are interested in targeting critical source areas for control strategy implementation. Currently, conservation practices are selected and located based on the Revised Universal Soil Loss Equation (RUSLE) hillslope erosion modeling, and the National Resource Conservation Service will soon be transiting to the Watershed Erosion Predict Project (WEPP) model for the same purpose. We present an assessment of critical source areas targeted with RUSLE, WEPP and a regionally validated hydrology model, the Soil Moisture Routing (SMR) model, to compare the location of critical areas for sediment loading and the effectiveness of control strategies. The three models are compared for the Palouse dryland cropping region of the inland northwest, with un-calibrated analyses of the Kamiache watershed using publicly available soils, land-use and long-term simulated climate data. Critical source areas were mapped and the side-by-side comparison exposes the differences in the location and timing of runoff and erosion predictions. RUSLE results appear most sensitive to slope driving processes associated with infiltration excess. SMR captured saturation excess driven runoff events located at the toe slope position, while WEPP was able to capture both infiltration excess and saturation excess processes depending on soil type and management. A methodology is presented for down-scaling basin level screening to the hillslope management scale for local control strategies. Information on the location of runoff and erosion, driven by the runoff mechanism, is critical for effective treatment and conservation.

  7. NSG Mice Provide a Better Spontaneous Model of Breast Cancer Metastasis than Athymic (Nude Mice.

    Directory of Open Access Journals (Sweden)

    Madhavi Puchalapalli

    Full Text Available Metastasis is the most common cause of mortality in breast cancer patients worldwide. To identify improved mouse models for breast cancer growth and spontaneous metastasis, we examined growth and metastasis of both estrogen receptor positive (T47D and negative (MDA-MB-231, SUM1315, and CN34BrM human breast cancer cells in nude and NSG mice. Both primary tumor growth and spontaneous metastases were increased in NSG mice compared to nude mice. In addition, a pattern of metastasis similar to that observed in human breast cancer patients (metastases to the lungs, liver, bones, brain, and lymph nodes was found in NSG mice. Furthermore, there was an increase in the metastatic burden in NSG compared to nude mice that were injected with MDA-MB-231 breast cancer cells in an intracardiac experimental metastasis model. This data demonstrates that NSG mice provide a better model for studying human breast cancer metastasis compared to the current nude mouse model.

  8. State and Alternative Fuel Provider Fleets - Fleet Compliance Annual Report: Model Year 2015, Fiscal Year 2016

    Energy Technology Data Exchange (ETDEWEB)

    2016-12-01

    The U.S. Department of Energy (DOE) regulates covered state government and alternative fuel provider fleets, pursuant to the Energy Policy Act of 1992 (EPAct), as amended. Covered fleets may meet their EPAct requirements through one of two compliance methods: Standard Compliance or Alternative Compliance. For model year (MY) 2015, the compliance rate with this program for the more than 3011 reporting fleets was 100%. More than 294 fleets used Standard Compliance and exceeded their aggregate MY 2015 acquisition requirements by 8% through acquisitions alone. The seven covered fleets that used Alternative Compliance exceeded their aggregate MY 2015 petroleum use reduction requirements by 46%.

  9. Critical Care

    Science.gov (United States)

    Critical care helps people with life-threatening injuries and illnesses. It might treat problems such as complications from surgery, ... attention by a team of specially-trained health care providers. Critical care usually takes place in an ...

  10. An Approach to Modeling Software Safety in Safety-Critical Systems

    OpenAIRE

    Ben S. Medikonda; Seetha R. Panchumarthy

    2009-01-01

    Software for safety-critical systems has to deal with the hazards identified by safety analysis in order to make the system safe, risk-free and fail-safe. Software safety is a composite of many factors. Problem statement: Existing software quality models like McCalls and Boehms and ISO 9126 were inadequate in addressing the software safety issues of real time safety-critical embedded systems. At present there does not exist any standard framework that comprehensively addresses the Factors, Cr...

  11. High-accuracy critical exponents for O(N) hierarchical 3D sigma models

    International Nuclear Information System (INIS)

    Godina, J. J.; Li, L.; Meurice, Y.; Oktay, M. B.

    2006-01-01

    The critical exponent γ and its subleading exponent Δ in the 3D O(N) Dyson's hierarchical model for N up to 20 are calculated with high accuracy. We calculate the critical temperatures for the measure δ(φ-vector.φ-vector-1). We extract the first coefficients of the 1/N expansion from our numerical data. We show that the leading and subleading exponents agree with Polchinski equation and the equivalent Litim equation, in the local potential approximation, with at least 4 significant digits

  12. Role of Defects in Self-Organized Criticality: A Directed Coupled Map Lattice Model

    OpenAIRE

    Tadic, Bosiljka; Ramaswamy, Ramakrishna

    1996-01-01

    We study a directed coupled map lattice model in two dimensions, with two degrees of freedom associated with each lattice site. The two freedoms are coupled at a fraction $c$ of lattice bonds acting as quenched random defects. In the case of conservative dynamics, at any concentration of defects the system reaches a self-organized critical state with universal critical exponents close to the mean-field values. The probability distributions follow the general scaling form $P(X,L)= L^{-\\alpha}{...

  13. Global demons in field theory. Critical slowing down in the XY model

    Science.gov (United States)

    Kusnezov, Dimitri; Sloan, John

    1993-12-01

    We investigate the use of global demons, a "canonical dynamics", as an approach to simulating lattice regularized field theories. This deterministically chaotic dynamics is non-local and non-hamiltonian, and preserves the canonical measure rather than δ( H - E). We apply this inexact dynamics to the 2D XY model, comparing to various implementations of hybrid Monte Carlo, focusing on critical exponents and critical slowing down. In addition, we discuss a scheme for making energy non-conserving dynamical algorithms exact without the use of a Metropolis hit.

  14. Critical ischemia time in a model of spinal cord section. A study performed on dogs

    OpenAIRE

    Bitar Alatorre, Wadih Emilio; Garcia Martinez, David; Rosales Corral, Sergio A.; Flores Soto, Mario E.; Velarde Silva, Gustavo; Portilla de Buen, Eliseo

    2006-01-01

    Vascular changes after acute spinal cord trauma are important factors that predispose quadriplegia, in most cases irreversible. Repair of the spinal blood flow helps the spinal cord recovery. The average time to arrive and perform surgery is 3 h in most cases. It is important to determine the critical ischemia time in order to offer better functional prognosis. A spinal cord section and vascular clamping of the spinal anterior artery at C5–C6 model was used to determine critical ischemia time...

  15. Synergy of air pollutants and greenhouse gas emissions of Chinese industries: A critical assessment of energy models

    International Nuclear Information System (INIS)

    Zhang, Shaohui; Worrell, Ernst; Crijns-Graus, Wina

    2015-01-01

    In China, industrial energy use accounts for two thirds of total energy consumption, and this is expected to remain the same in the medium and long-term. China has embarked on a path towards more sustainable energy use to meet domestic (e.g. air quality) and global needs (e.g. climate change), and to sustain its economic welfare. However, most energy-economy models for China have shown limitations to evaluate policy instruments and technology diffusion in industries, in relation to the multiple policy goals. In this paper, the advantages and weaknesses of 19 current energy models for China are evaluated, including important co-benefits as reduced air pollutant emissions. Results show that the co-benefits of energy use and emission policies are rarely modeled on industrial level. Based on the critical assessment of the state-of-the-art energy models, we develop recommendations for modeling industrial energy use, with an emphasis on improved incorporation of (economic, environmental and energy) policy effects, technology representation, co-benefit modeling, and uncertainty analysis. - Highlights: • This study evaluates 19 the state-of-the-art energy models on different level. • The co-benefits of different policies are rarely reported in energy models. • Technology plays a key role in models when assessing the co-benefits. • The integrated models provide a better understanding to evaluate the co-benefits. • The directions to improve the accuracy of the current energy models are presented.

  16. Critical Domain Problem for the Reaction–Telegraph Equation Model of Population Dynamics

    Directory of Open Access Journals (Sweden)

    Weam Alharbi

    2018-04-01

    Full Text Available A telegraph equation is believed to be an appropriate model of population dynamics as it accounts for the directional persistence of individual animal movement. Being motivated by the problem of habitat fragmentation, which is known to be a major threat to biodiversity that causes species extinction worldwide, we consider the reaction–telegraph equation (i.e., telegraph equation combined with the population growth on a bounded domain with the goal to establish the conditions of species survival. We first show analytically that, in the case of linear growth, the expression for the domain’s critical size coincides with the critical size of the corresponding reaction–diffusion model. We then consider two biologically relevant cases of nonlinear growth, i.e., the logistic growth and the growth with a strong Allee effect. Using extensive numerical simulations, we show that in both cases the critical domain size of the reaction–telegraph equation is larger than the critical domain size of the reaction–diffusion equation. Finally, we discuss possible modifications of the model in order to enhance the positivity of its solutions.

  17. A critical examination of the youth foyer model for alleviating homelessness: Strengthening a promising evidence base

    Directory of Open Access Journals (Sweden)

    Iris Levin

    2015-12-01

    Full Text Available This article assesses the quality of 15 primary studies that examined the effectiveness of youth foyer or foyer-like programs on the lives of young homeless people. The youth foyer model provides an integrated approach to tackling youth homelessness, connecting affordable accommodation to training and employment. In Australia, there is growing support from government for the development and funding of foyer programs. However to date, there has been very limited development and investment in the evidence base on the effectiveness of this model in Australia or internationally. Following an extensive literature search, we argue that there is a need to lift the standard of the evidence base of youth foyer effectiveness. We discuss two main issues: the difficulty studies had validating claims of foyer effectiveness, and limitations of research design and methodology. The implications of the lack of rigour in the research reviewed are three-fold. Firstly, youth foyer evaluation study quality could be improved by: clearer methodological and model documentation; post intervention follow-up design; comparison of data to non-randomised comparison groups; and a pre-publication peer-review process. This would be supported with clearer expectations from the research community regarding the production and assessment of grey literature. Secondly, while the standard of reporting needs to be raised, the ‘gold standard’ (i.e. randomised controlled trials of research design in the scientific community is not a relevant benchmark in the field of homelessness research. This is due to the complexity of homelessness interventions and the inadequate funding of the homelessness research field. Greater investment in robust research and evaluation should accompany the substantial investment in youth foyer programs in order to accurately appraise the effectiveness of the youth foyer model. Thirdly, the lack of rigour in the studies reviewed suggests gaps in the service

  18. Global observations and modeling of atmosphere–surface exchange of elemental mercury: a critical review

    Directory of Open Access Journals (Sweden)

    W. Zhu

    2016-04-01

    Full Text Available Reliable quantification of air–surface fluxes of elemental Hg vapor (Hg0 is crucial for understanding mercury (Hg global biogeochemical cycles. There have been extensive measurements and modeling efforts devoted to estimating the exchange fluxes between the atmosphere and various surfaces (e.g., soil, canopies, water, snow, etc. in the past three decades. However, large uncertainties remain due to the complexity of Hg0 bidirectional exchange, limitations of flux quantification techniques and challenges in model parameterization. In this study, we provide a critical review on the state of science in the atmosphere–surface exchange of Hg0. Specifically, the advancement of flux quantification techniques, mechanisms in driving the air–surface Hg exchange and modeling efforts are presented. Due to the semi-volatile nature of Hg0 and redox transformation of Hg in environmental media, Hg deposition and evasion are influenced by multiple environmental variables including seasonality, vegetative coverage and its life cycle, temperature, light, moisture, atmospheric turbulence and the presence of reactants (e.g., O3, radicals, etc.. However, the effects of these processes on flux have not been fundamentally and quantitatively determined, which limits the accuracy of flux modeling. We compile an up-to-date global observational flux database and discuss the implication of flux data on the global Hg budget. Mean Hg0 fluxes obtained by micrometeorological measurements do not appear to be significantly greater than the fluxes measured by dynamic flux chamber methods over unpolluted surfaces (p = 0.16, one-tailed, Mann–Whitney U test. The spatiotemporal coverage of existing Hg0 flux measurements is highly heterogeneous with large data gaps existing in multiple continents (Africa, South Asia, Middle East, South America and Australia. The magnitude of the evasion flux is strongly enhanced by human activities, particularly at contaminated sites. Hg0

  19. Impacts of Quaternary History on Critical Zone Structure and Processes: Examples and a Conceptual Model From the Intensively Managed Landscapes Critical Zone Observatory

    Directory of Open Access Journals (Sweden)

    Alison M. Anders

    2018-03-01

    Full Text Available The concept of a critical zone (CZ supporting terrestrial life has fostered groundbreaking interdisciplinary science addressing complex interactions among water, soil, rock, air, and life near Earth's surface. Pioneering work has focused on the CZ in areas with residual soils and steady-state or erosional topography. CZ evolution in these areas is conceptualized as progressive weathering of local bedrock (e.g., in the flow-through reactor model. However, this model is not applicable to areas in which weathering profiles form in transported materials including the formerly glaciated portion of the Central Lowland of North America. We present a new conceptual model of CZ evolution in landscapes impacted by continental glaciation based on investigations at three study sites in the Intensively Managed Landscapes Critical Zone Observatory (IML-CZO The IML-CZO is devoted to the study of CZ processes in a region characterized by thick surficial deposits resulting from multiple continental glaciations, with bedrock at depths of up to 150 m. Here the physical (glacial ice, loess, developing soil profiles and biological (microbes, tundra, forest, prairie components of the CZ vary significantly in time. Moreover, the spatial relationships between mineral components of the CZ record a history of glacial-interglacial cycles and landscape evolution. We present cross-sections from IML-CZO sites to provide specific examples of how environmental change is recorded by the structure of the mineral components of the CZ. We build on these examples to create an idealized model of CZ evolution through a glacial cycle that represents the IML-CZO sites and other areas of low relief that have experienced continental glaciation. In addition, we identify two main characteristics of CZ structure which should be included in a conceptual model of CZ development in the IML-CZO and similar settings: (1 mineral components have diverse origins and transport trajectories including

  20. Quantum critical behavior in three-dimensional one-band Hubbard model at half-filling

    International Nuclear Information System (INIS)

    Karchev, Naoum

    2013-01-01

    A one-band Hubbard model with hopping parameter t and Coulomb repulsion U is considered at half-filling. By means of the Schwinger bosons and slave fermions representation of the electron operators and integrating out the spin–singlet Fermi fields an effective Heisenberg model with antiferromagnetic exchange constant is obtained for vectors which identifies the local orientation of the spin of the itinerant electrons. The amplitude of the spin vectors is an effective spin of the itinerant electrons accounting for the fact that some sites, in the ground state, are doubly occupied or empty. Accounting adequately for the magnon–magnon interaction the Néel temperature is calculated. When the ratio t/U is small enough (t/U ≤0.09) the effective model describes a system of localized electrons. Increasing the ratio increases the density of doubly occupied states which in turn decreases the effective spin and Néel temperature. The phase diagram in the plane of temperature (T N )/U and parameter t/U is presented. The quantum critical point (T N =0) is reached at t/U =0.9. The magnons in the paramagnetic phase are studied and the contribution of the magnons’ fluctuations to the heat capacity is calculated. At the Néel temperature the heat capacity has a peak which is suppressed when the system approaches a quantum critical point. It is important to stress that, at half-filling, the ground state, determined by fermions, is antiferromagnetic. The magnon fluctuations drive the system to quantum criticality and when the effective spin is critically small these fluctuations suppress the magnetic order. -- Highlights: •Technique of calculation is introduced which permits us to study the magnons’ fluctuations. •Quantum critical point is obtained in the one-band 3D Hubbard model at half-filling. •The present analytical results supplement the numerical ones (see Fig. 7)

  1. Using Performance Assessment Model in Physics Laboratory to Increase Students’ Critical Thinking Disposition

    Science.gov (United States)

    Emiliannur, E.; Hamidah, I.; Zainul, A.; Wulan, A. R.

    2017-09-01

    Performance Assessment Model (PAM) has been developed to represent the physics concepts which able to be devided into five experiments: 1) acceleration due to gravity; 2) Hooke’s law; 3) simple harmonic motion; 4) work-energy concepts; and 5) the law of momentum conservation. The aim of this study was to determine the contribution of PAM in physics laboratory to increase students’ Critical Thinking Disposition (CTD) at senior high school. Subject of the study were 11th grade consist 32 students of a senior high school in Lubuk Sikaping, West Sumatera. The research used one group pretest-postest design. Data was collected through essay test and questionnaire about CTD. Data was analyzed using quantitative way with N-gain value. This study concluded that performance assessmet model effectively increases the N-gain at medium category. It means students’ critical thinking disposition significant increase after implementation of performance assessment model in physics laboratory.

  2. Critical appraisal of alternative irritation models: three decades of testing ophthalmic pharmaceuticals.

    Science.gov (United States)

    Abdelkader, Hamdy; Pierscionek, Barbara; Carew, Mark; Wu, Zimei; Alany, Raid G

    2015-03-01

    Testing ocular tolerability of ocular pharmaceuticals is an essential regulatory requirement. The current approved reference model (gold standard) for ocular irritation testing is the Draize test. However this method is subjective and involves using live animals, hence the need to develop alternative in vitro and ex vivo testing strategies. Pubmed, Science Direct, Scopus, Google Scholar, Medline, Current Content, Web of Science and validation reports from international regulatory bodies; The Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) and European Centre for the Validation of Alternative Methods (ECVAM) were searched for in vitro alternatives. Whilst no single in vitro test can effectively replace the Draize eye irritation test, regulatory bodies and cosmetic/pharmaceutical industries agree that there is a need for in vitro alternatives with validated endpoints to evaluate pharmaceutical ingredients and finished eye products. There is no single in vitro test / assay that can predict the ocular irritation potential of mild to moderate test substances. This review provides a critical appraisal of the selected in vitro and ex vivo ocular toxicity models recommended by international regulatory bodies. These include cytotoxicity methods, biochemical systems and ex vivo assays. The latter are approved by ECVAM as in vitro alternatives for the well-known Draize test. Hen's egg test-chorioallantoic membrane and the isolated rabbit eye test are also accepted by regulatory agencies in France, Germany, the Netherlands and the UK. A combination of ex vivo assays along with histological examination of excised bovine cornea can predict the conjunctival and corneal tolerability and cover a wider range of ocular pharmaceutical substances. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Modelling the tuned criticality in stick-slip friction during metal cutting

    International Nuclear Information System (INIS)

    Wang, Q; Ye, G G; Dai, L H; Lu, C

    2015-01-01

    Cutting is a ubiquitous process in nature and man-made systems. Here we demonstrate that, based on morphological patterns observed in experiments, the friction behaviour of metal cutting exhibits a criticality with cutting speed as a tuned parameter. The corresponding stick-slip events can be described by a power law distribution. A dynamic thermo-mechanical model is developed to investigate how such a tuned criticality occurs. It is shown that, in terms of the linear stability analysis, stick-slip friction is due to the thermo-mechanical instability and dynamical interaction between shear dissipation and nonlinear friction. Moreover, there is a secondary transition from a criticality state to a limit cycle that is dominated by the inertia effect, which is similar to the frequency lock phenomenon in a forced Duffing oscillator. (paper)

  4. Providing Context for Complexity: Using Infographics and Conceptual Models to Teach Global Change Processes

    Science.gov (United States)

    Bean, J. R.; White, L. D.

    2015-12-01

    Understanding modern and historical global changes requires interdisciplinary knowledge of the physical and life sciences. The Understanding Global Change website from the UC Museum of Paleontology will use a focal infographic that unifies diverse content often taught in separate K-12 science units. This visualization tool provides scientists with a structure for presenting research within the broad context of global change, and supports educators with a framework for teaching and assessing student understanding of complex global change processes. This new approach to teaching the science of global change is currently being piloted and refined based on feedback from educators and scientists in anticipation of a 2016 website launch. Global change concepts are categorized within the infographic as causes of global change (e.g., burning of fossil fuels, volcanism), ongoing Earth system processes (e.g., ocean circulation, the greenhouse effect), and the changes scientists measure in Earth's physical and biological systems (e.g., temperature, extinctions/radiations). The infographic will appear on all website content pages and provides a template for the creation of flowcharts, which are conceptual models that allow teachers and students to visualize the interdependencies and feedbacks among processes in the atmosphere, hydrosphere, biosphere, and geosphere. The development of this resource is timely given that the newly adopted Next Generation Science Standards emphasize cross-cutting concepts, including model building, and Earth system science. Flowchart activities will be available on the website to scaffold inquiry-based lessons, determine student preconceptions, and assess student content knowledge. The infographic has already served as a learning and evaluation tool during professional development workshops at UC Berkeley, Stanford University, and the Smithsonian National Museum of Natural History. At these workshops, scientists and educators used the infographic

  5. MODEL REQUEST FOR PROPOSALS TO PROVIDE ENERGY AND OTHER ATTRIBUTES FROM AN OFFSHORE WIND POWER PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    Jeremy Firestone; Dawn Kurtz Crompton

    2011-10-22

    This document provides a model RFP for new generation. The 'base' RFP is for a single-source offshore wind RFP. Required modifications are noted should a state or utility seek multi-source bids (e.g., all renewables or all sources). The model is premised on proposals meeting threshold requirements (e.g., a MW range of generating capacity and a range in terms of years), RFP issuer preferences (e.g., likelihood of commercial operation by a date certain, price certainty, and reduction in congestion), and evaluation criteria, along with a series of plans (e.g., site, environmental effects, construction, community outreach, interconnection, etc.). The Model RFP places the most weight on project risk (45%), followed by project economics (35%), and environmental and social considerations (20%). However, if a multi-source RFP is put forward, the sponsor would need to either add per-MWh technology-specific, life-cycle climate (CO2), environmental and health impact costs to bid prices under the 'Project Economics' category or it should increase the weight given to the 'Environmental and Social Considerations' category.

  6. Mathematical modeling provides kinetic details of the human immune response to vaccination

    Directory of Open Access Journals (Sweden)

    Dustin eLe

    2015-01-01

    Full Text Available With major advances in experimental techniques to track antigen-specific immune responses many basic questions on the kinetics of virus-specific immunity in humans remain unanswered. To gain insights into kinetics of T and B cell responses in human volunteers we combine mathematical models and experimental data from recent studies employing vaccines against yellow fever and smallpox. Yellow fever virus-specific CD8 T cell population expanded slowly with the average doubling time of 2 days peaking 2.5 weeks post immunization. Interestingly, we found that the peak of the yellow fever-specific CD8 T cell response is determined by the rate of T cell proliferation and not by the precursor frequency of antigen-specific cells as has been suggested in several studies in mice. We also found that while the frequency of virus-specific T cells increases slowly, the slow increase can still accurately explain clearance of yellow fever virus in the blood. Our additional mathematical model describes well the kinetics of virus-specific antibody-secreting cell and antibody response to vaccinia virus in vaccinated individuals suggesting that most of antibodies in 3 months post immunization are derived from the population of circulating antibody-secreting cells. Taken together, our analysis provides novel insights into mechanisms by which live vaccines induce immunity to viral infections and highlight challenges of applying methods of mathematical modeling to the current, state-of-the-art yet limited immunological data.

  7. Mathematical modeling provides kinetic details of the human immune response to vaccination.

    Science.gov (United States)

    Le, Dustin; Miller, Joseph D; Ganusov, Vitaly V

    2014-01-01

    With major advances in experimental techniques to track antigen-specific immune responses many basic questions on the kinetics of virus-specific immunity in humans remain unanswered. To gain insights into kinetics of T and B cell responses in human volunteers we combined mathematical models and experimental data from recent studies employing vaccines against yellow fever and smallpox. Yellow fever virus-specific CD8 T cell population expanded slowly with the average doubling time of 2 days peaking 2.5 weeks post immunization. Interestingly, we found that the peak of the yellow fever-specific CD8 T cell response was determined by the rate of T cell proliferation and not by the precursor frequency of antigen-specific cells as has been suggested in several studies in mice. We also found that while the frequency of virus-specific T cells increased slowly, the slow increase could still accurately explain clearance of yellow fever virus in the blood. Our additional mathematical model described well the kinetics of virus-specific antibody-secreting cell and antibody response to vaccinia virus in vaccinated individuals suggesting that most of antibodies in 3 months post immunization were derived from the population of circulating antibody-secreting cells. Taken together, our analysis provided novel insights into mechanisms by which live vaccines induce immunity to viral infections and highlighted challenges of applying methods of mathematical modeling to the current, state-of-the-art yet limited immunological data.

  8. Guarana Provides Additional Stimulation over Caffeine Alone in the Planarian Model

    Science.gov (United States)

    Moustakas, Dimitrios; Mezzio, Michael; Rodriguez, Branden R.; Constable, Mic Andre; Mulligan, Margaret E.; Voura, Evelyn B.

    2015-01-01

    The stimulant effect of energy drinks is primarily attributed to the caffeine they contain. Many energy drinks also contain other ingredients that might enhance the tonic effects of these caffeinated beverages. One of these additives is guarana. Guarana is a climbing plant native to the Amazon whose seeds contain approximately four times the amount of caffeine found in coffee beans. The mix of other natural chemicals contained in guarana seeds is thought to heighten the stimulant effects of guarana over caffeine alone. Yet, despite the growing use of guarana as an additive in energy drinks, and a burgeoning market for it as a nutritional supplement, the science examining guarana and how it affects other dietary ingredients is lacking. To appreciate the stimulant effects of guarana and other natural products, a straightforward model to investigate their physiological properties is needed. The planarian provides such a system. The locomotor activity and convulsive response of planarians with substance exposure has been shown to provide an excellent system to measure the effects of drug stimulation, addiction and withdrawal. To gauge the stimulant effects of guarana we studied how it altered the locomotor activity of the planarian species Dugesia tigrina. We report evidence that guarana seeds provide additional stimulation over caffeine alone, and document the changes to this stimulation in the context of both caffeine and glucose. PMID:25880065

  9. Guarana provides additional stimulation over caffeine alone in the planarian model.

    Directory of Open Access Journals (Sweden)

    Dimitrios Moustakas

    Full Text Available The stimulant effect of energy drinks is primarily attributed to the caffeine they contain. Many energy drinks also contain other ingredients that might enhance the tonic effects of these caffeinated beverages. One of these additives is guarana. Guarana is a climbing plant native to the Amazon whose seeds contain approximately four times the amount of caffeine found in coffee beans. The mix of other natural chemicals contained in guarana seeds is thought to heighten the stimulant effects of guarana over caffeine alone. Yet, despite the growing use of guarana as an additive in energy drinks, and a burgeoning market for it as a nutritional supplement, the science examining guarana and how it affects other dietary ingredients is lacking. To appreciate the stimulant effects of guarana and other natural products, a straightforward model to investigate their physiological properties is needed. The planarian provides such a system. The locomotor activity and convulsive response of planarians with substance exposure has been shown to provide an excellent system to measure the effects of drug stimulation, addiction and withdrawal. To gauge the stimulant effects of guarana we studied how it altered the locomotor activity of the planarian species Dugesia tigrina. We report evidence that guarana seeds provide additional stimulation over caffeine alone, and document the changes to this stimulation in the context of both caffeine and glucose.

  10. A framework for modeling information propagation of biological systems at critical states.

    Science.gov (United States)

    Hu, Feng; Yang, Fang

    2016-03-01

    We explore the dynamics of information propagation at the critical state of a biologically inspired system by an individual-based computer model. "Quorum response", a type of social interaction which has been recognized taxonomically in animal groups, is applied as the sole interaction rule among individuals. In the model, we assume a truncated Gaussian distribution to depict the distribution of the individuals' vigilance level. Each individual can assume either a naïve state or an alarmed one and only switches from the former state to the latter one. If an individual has turned into an alarmed state, it stays in the state during the process of information propagation. Initially, each individual is set to be at the naïve state and information is tapped into the system by perturbing an individual at the boundaries (alerting it to the alarmed state). The system evolves as individuals turn into the alarmed state, according to the quorum response rules, consecutively. We find that by fine-tuning the parameters of the mean and the standard deviation of the Gaussian distribution, the system is poised at a critical state. We present the phase diagrams to exhibit that the parameter space is divided into a super-critical and a sub-critical zone, in which the dynamics of information propagation varies largely. We then investigate the effects of the individuals' mobility on the critical state, and allow a proportion of randomly chosen individuals to exchange their positions at each time step. We find that mobility breaks down criticality of the system. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  11. The Nordic welfare model providing energy transition? A political geography approach to the EU RES directive

    International Nuclear Information System (INIS)

    Westholm, Erik; Beland Lindahl, Karin

    2012-01-01

    The EU Renewable Energy Strategy (RES) Directive requires that each member state obtain 20% of its energy supply from renewable sources by 2020. If fully implemented, this implies major changes in institutions, infrastructure, land use, and natural resource flows. This study applies a political geography perspective to explore the transition to renewable energy use in the heating and cooling segment of the Swedish energy system, 1980–2010. The Nordic welfare model, which developed mainly after the Second World War, required relatively uniform, standardized local and regional authorities functioning as implementation agents for national politics. Since 1980, the welfare orientation has gradually been complemented by competition politics promoting technological change, innovation, and entrepreneurship. This combination of welfare state organization and competition politics provided the dynamics necessary for energy transition, which occurred in a semi-public sphere of actors at various geographical scales. However, our analysis, suggest that this was partly an unintended policy outcome, since it was based on a welfare model with no significant energy aims. Our case study suggests that state organization plays a significant role, and that the EU RES Directive implementation will be uneven across Europe, reflecting various welfare models with different institutional pre-requisites for energy transition. - Highlights: ► We explore the energy transition in the heating/cooling sector in Sweden 1980–2000. ► The role of the state is studied from a political geography perspective. ► The changing welfare model offered the necessary institutional framework. ► Institutional arrangements stand out as central to explain the relative success. ► The use of renewables in EU member states will continue to vary significantly.

  12. Biological Model Development as an Opportunity to Provide Content Auditing for the Foundational Model of Anatomy Ontology.

    Science.gov (United States)

    Wang, Lucy L; Grunblatt, Eli; Jung, Hyunggu; Kalet, Ira J; Whipple, Mark E

    2015-01-01

    Constructing a biological model using an established ontology provides a unique opportunity to perform content auditing on the ontology. We built a Markov chain model to study tumor metastasis in the regional lymphatics of patients with head and neck squamous cell carcinoma (HNSCC). The model attempts to determine regions with high likelihood for metastasis, which guides surgeons and radiation oncologists in selecting the boundaries of treatment. To achieve consistent anatomical relationships, the nodes in our model are populated using lymphatic objects extracted from the Foundational Model of Anatomy (FMA) ontology. During this process, we discovered several classes of inconsistencies in the lymphatic representations within the FMA. We were able to use this model building opportunity to audit the entities and connections in this region of interest (ROI). We found five subclasses of errors that are computationally detectable and resolvable, one subclass of errors that is computationally detectable but unresolvable, requiring the assistance of a content expert, and also errors of content, which cannot be detected through computational means. Mathematical descriptions of detectable errors along with expert review were used to discover inconsistencies and suggest concepts for addition and removal. Out of 106 organ and organ parts in the ROI, 8 unique entities were affected, leading to the suggestion of 30 concepts for addition and 4 for removal. Out of 27 lymphatic chain instances, 23 were found to have errors, with a total of 32 concepts suggested for addition and 15 concepts for removal. These content corrections are necessary for the accurate functioning of the FMA and provide benefits for future research and educational uses.

  13. Tuning hydrological models for ecological modeling - improving simulations of low flows critical to stream ecology

    DEFF Research Database (Denmark)

    Olsen, Martin; Troldborg, Lars; Boegh, Eva

    2008-01-01

    The consequences of using simulated discharge from a conventional hydrological model as input in stream physical habitat modelling was investigated using output from the Danish national hydrological model and a physical habitat model of three small streams. It was found that low flow simulation...... errors could have large impact on simulation of physical habitat conditions. If these two models are to be used to assess groundwater abstraction impact on physical habitat conditions the hydrological model should be tuned to the purpose...

  14. Tuning hydrological models for ecological modeling – improving simulations of low flows critical to stream ecology

    DEFF Research Database (Denmark)

    Olsen, Martin; Troldborg, Lars; Boegh, Eva

    2008-01-01

    The consequences of using simulated discharge from a conventional hydrological model as input in stream physical habitat modelling was investigated using output from the Danish national hydrological model and a physical habitat model of three small streams. It was found that low flow simulation...... errors could have large impact on simulation of physical habitat conditions. If these two models are to be used to assess groundwater abstraction impact on physical habitat conditions the hydrological model should be tuned to the purpose...

  15. A model for determining when an analysis contains sufficient detail to provide adequate NEPA coverage for a proposed action

    International Nuclear Information System (INIS)

    Eccleston, C.H.

    1994-11-01

    Neither the National Environmental Policy Act (NEPA) nor its subsequent regulations provide substantive guidance for determining the Level of detail, discussion, and analysis that is sufficient to adequately cover a proposed action. Yet, decisionmakers are routinely confronted with the problem of making such determinations. Experience has shown that no two decisionmakers are Likely to completely agree on the amount of discussion that is sufficient to adequately cover a proposed action. one decisionmaker may determine that a certain Level of analysis is adequate, while another may conclude the exact opposite. Achieving a consensus within the agency and among the public can be problematic. Lacking definitive guidance, decisionmakers and critics alike may point to a universe of potential factors as the basis for defending their claim that an action is or is not adequately covered. Experience indicates that assertions are often based on ambiguous opinions that can be neither proved nor disproved. Lack of definitive guidance slows the decisionmaking process and can result in project delays. Furthermore, it can also Lead to inconsistencies in decisionmaking, inappropriate Levels of NEPA documentation, and increased risk of a project being challenged for inadequate coverage. A more systematic and less subjective approach for making such determinations is obviously needed. A paradigm for reducing the degree of subjectivity inherent in such decisions is presented in the following paper. The model is specifically designed to expedite the decisionmaking process by providing a systematic approach for making these determination. In many cases, agencies may find that using this model can reduce the analysis and size of NEPA documents

  16. Ecosystem Services Provided by Agricultural Land as Modeled by Broad Scale Geospatial Analysis

    Science.gov (United States)

    Kokkinidis, Ioannis

    Agricultural ecosystems provide multiple services including food and fiber provision, nutrient cycling, soil retention and water regulation. Objectives of the study were to identify and quantify a selection of ecosystem services provided by agricultural land, using existing geospatial tools and preferably free and open source data, such as the Virginia Land Use Evaluation System (VALUES), the North Carolina Realistic Yield Expectations (RYE) database, and the land cover datasets NLCD and CDL. Furthermore I sought to model tradeoffs between provisioning and other services. First I assessed the accuracy of agricultural land in NLCD and CDL over a four county area in eastern Virginia using cadastral parcels. I uncovered issues concerning the definition of agricultural land. The area and location of agriculture saw little change in the 19 years studied. Furthermore all datasets have significant errors of omission (11.3 to 95.1%) and commission (0 to 71.3%). Location of agriculture was used with spatial crop yield databases I created and combined with models I adapted to calculate baseline values for plant biomass, nutrient composition and requirements, land suitability for and potential production of biofuels and the economic impact of agriculture for the four counties. The study area was then broadened to cover 97 counties in eastern Virginia and North Carolina, investigating the potential for increased regional grain production through intensification and extensification of agriculture. Predicted yield from geospatial crop models was compared with produced yield from the NASS Survey of Agriculture. Area of most crops in CDL was similar to that in the Survey of Agriculture, but a yield gap is present for most years, partially due to weather, thus indicating potential for yield increase through intensification. Using simple criteria I quantified the potential to extend agriculture in high yield land in other uses and modeled the changes in erosion and runoff should

  17. An improved mechanistic critical heat flux model for subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Young Min [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1997-12-31

    Based on the bubble coalescence adjacent to the heated wall as a flow structure for CHF condition, Chang and Lee developed a mechanistic critical heat flux (CHF) model for subcooled flow boiling. In this paper, improvements of Chang-Lee model are implemented with more solid theoretical bases for subcooled and low-quality flow boiling in tubes. Nedderman-Shearer`s equations for the skin friction factor and universal velocity profile models are employed. Slip effect of movable bubbly layer is implemented to improve the predictability of low mass flow. Also, mechanistic subcooled flow boiling model is used to predict the flow quality and void fraction. The performance of the present model is verified using the KAIST CHF database of water in uniformly heated tubes. It is found that the present model can give a satisfactory agreement with experimental data within less than 9% RMS error. 9 refs., 5 figs. (Author)

  18. An integrated decision making model for the selection of sustainable forward and reverse logistic providers

    DEFF Research Database (Denmark)

    Govindan, Kannan; Agarwal, Vernika; Darbari, Jyoti Dhingra

    2017-01-01

    Due to rising concerns for environmental sustainability, the Indian electronic industry faces immense pressure to incorporate effective sustainable practices into the supply chain (SC) planning. Consequently, manufacturing enterprises (ME) are exploring the option of re-examining their SC...... hierarchy process and the technique for order performance by similarity to ideal solution. The integrated logistics network is modeled as a bi-objective mixed-integer programming problem with the objective of maximizing the profit of the manufacturer and maximizing the sustainable score of the selected...... improve the sustainable performance value of the SC network and secure reasonable profits. The managerial implications drawn from the result analysis provide a sustainable framework to the ME for enhancing its corporate image....

  19. Lipopolysaccharide from Burkholderia thailandensis E264 provides protection in a murine model of melioidosis.

    Science.gov (United States)

    Ngugi, Sarah A; Ventura, Valeria V; Qazi, Omar; Harding, Sarah V; Kitto, G Barrie; Estes, D Mark; Dell, Anne; Titball, Richard W; Atkins, Timothy P; Brown, Katherine A; Hitchen, Paul G; Prior, Joann L

    2010-11-03

    Burkholderia thailandensis is a less virulent close relative of Burkholderia pseudomallei, a CDC category B biothreat agent. We have previously shown that lipopolysaccharide (LPS) extracted from B. pseudomallei can provide protection against a lethal challenge of B. pseudomallei in a mouse model of melioidosis. Sugar analysis on LPS from B. thailandensis strain E264 confirmed that this polysaccharide has a similar structure to LPS from B. pseudomallei. Mice were immunised with LPS from B. thailandensis or B. pseudomallei and challenged with a lethal dose of B. pseudomallei strain K96243. Similar protection levels were observed when either LPS was used as the immunogen. This data suggests that B. thailandensis LPS has the potential to be used as part of a subunit based vaccine against pathogenic B. pseudomallei. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

  20. Collaborative Care: a Pilot Study of a Child Psychiatry Outpatient Consultation Model for Primary Care Providers.

    Science.gov (United States)

    Fallucco, Elise M; Blackmore, Emma Robertson; Bejarano, Carolina M; Kozikowksi, Chelsea B; Cuffe, Steven; Landy, Robin; Glowinski, Anne

    2017-07-01

    A Child Psychiatry Consultation Model (CPCM) offering primary care providers (PCPs) expedited access to outpatient child psychiatric consultation regarding management in primary care would allow more children to access mental health services. Yet, little is known about outpatient CPCMs. This pilot study describes an outpatient CPCM for 22 PCPs in a large Northeast Florida county. PCPs referred 81 patients, of which 60 were appropriate for collaborative management and 49 were subsequently seen for outpatient psychiatric consultation. The most common psychiatric diagnoses following consultation were anxiety (57%), ADHD (53%), and depression (39%). Over half (57%) of the patients seen for consultation were discharged to their PCP with appropriate treatment recommendations, and only a small minority (10%) of patients required long-term care by a psychiatrist. This CPCM helped child psychiatrists collaborate with PCPs to deliver mental health services for youth. The CPCM should be considered for adaptation and dissemination.

  1. The fornix provides multiple biomarkers to characterize circuit disruption in a mouse model of Alzheimer's disease.

    Science.gov (United States)

    Badea, Alexandra; Kane, Lauren; Anderson, Robert J; Qi, Yi; Foster, Mark; Cofer, Gary P; Medvitz, Neil; Buckley, Anne F; Badea, Andreas K; Wetsel, William C; Colton, Carol A

    2016-11-15

    Multivariate biomarkers are needed for detecting Alzheimer's disease (AD), understanding its etiology, and quantifying the effect of therapies. Mouse models provide opportunities to study characteristics of AD in well-controlled environments that can help facilitate development of early interventions. The CVN-AD mouse model replicates multiple AD hallmark pathologies, and we identified multivariate biomarkers characterizing a brain circuit disruption predictive of cognitive decline. In vivo and ex vivo magnetic resonance imaging (MRI) revealed that CVN-AD mice replicate the hippocampal atrophy (6%), characteristic of humans with AD, and also present changes in subcortical areas. The largest effect was in the fornix (23% smaller), which connects the septum, hippocampus, and hypothalamus. In characterizing the fornix with diffusion tensor imaging, fractional anisotropy was most sensitive (20% reduction), followed by radial (15%) and axial diffusivity (2%), in detecting pathological changes. These findings were strengthened by optical microscopy and ultrastructural analyses. Ultrastructual analysis provided estimates of axonal density, diameters, and myelination-through the g-ratio, defined as the ratio between the axonal diameter, and the diameter of the axon plus the myelin sheath. The fornix had reduced axonal density (47% fewer), axonal degeneration (13% larger axons), and abnormal myelination (1.5% smaller g-ratios). CD68 staining showed that white matter pathology could be secondary to neuronal degeneration, or due to direct microglial attack. In conclusion, these findings strengthen the hypothesis that the fornix plays a role in AD, and can be used as a disease biomarker and as a target for therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Probing the Relationship Between Evidence-Based Practice Implementation Models and Critical Thinking in Applied Nursing Practice.

    Science.gov (United States)

    Canada, Amanda N

    2016-04-01

    HOW TO OBTAIN CONTACT HOURS BY READING THIS ISSUE Instructions: 1.2 contact hours will be awarded by Villanova University College of Nursing upon successful completion of this activity. A contact hour is a unit of measurement that denotes 60 minutes of an organized learning activity. This is a learner-based activity. Villanova University College of Nursing does not require submission of your answers to the quiz. A contact hour certificate will be awarded after you register, pay the registration fee, and complete the evaluation form online at http://goo.gl/gMfXaf. In order to obtain contact hours you must: 1. Read the article, "Probing the Relationship Between Evidence-Based Practice Implementation Models and Critical Thinking in Applied Nursing Practice," found on pages 161-168, carefully noting any tables and other illustrative materials that are included to enhance your knowledge and understanding of the content. Be sure to keep track of the amount of time (number of minutes) you spend reading the article and completing the quiz. 2. Read and answer each question on the quiz. After completing all of the questions, compare your answers to those provided within this issue. If you have incorrect answers, return to the article for further study. 3. Go to the Villanova website to register for contact hour credit. You will be asked to provide your name, contact information, and a VISA, MasterCard, or Discover card number for payment of the $20.00 fee. Once you complete the online evaluation, a certificate will be automatically generated. This activity is valid for continuing education credit until March 31, 2019. CONTACT HOURS This activity is co-provided by Villanova University College of Nursing and SLACK Incorporated. Villanova University College of Nursing is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's Commission on Accreditation. • Describe the key components and characteristics related to evidence

  3. Cameroon mid-level providers offer a promising public health dentistry model

    Directory of Open Access Journals (Sweden)

    Achembong Leo

    2012-11-01

    Full Text Available Background Oral health services are inadequate and unevenly distributed in many developing countries, particularly those in sub-Saharan Africa. Rural areas in these countries and poorer sections of the population in urban areas often do not have access to oral health services mainly because of a significant shortage of dentists and the high costs of care. We reviewed Cameroon’s experience with deploying a mid-level cadre of oral health professionals and the feasibility of establishing a more formal and predictable role for these health workers. We anticipate that a task-shifting approach in the provision of dental care will significantly improve the uneven distribution of oral health services particularly in the rural areas of Cameroon, which is currently served by only 3% of the total number of dentists. Methods The setting of this study was the Cameroon Baptist Convention Health Board (BCHB, which has four dentists and 42 mid-level providers. De-identified data were collected manually from the registries of 10 Baptist Convention clinics located in six of Cameroon’s 10 regions and then entered into an Excel format before importing into STATA. A retrospective abstraction of all entries for patient visits starting October 2010, and going back in time until 1500 visits were extracted from each clinic. Results This study showed that mid-level providers in BCHB clinics are offering a full scope of dental work across the 10 clinics, with the exception of treatment for major facial injuries. Mid-level providers alone performed 93.5% of all extractions, 87.5% of all fillings, 96.5% of all root canals, 97.5% of all cleanings, and 98.1% of all dentures. The dentists also typically played a teaching role in training the mid-level providers. Conclusions The Ministry of Health in Cameroon has an opportunity to learn from the BCHB model to expand access to oral health care across the country. This study shows the benefits of using a simple, workable, low

  4. Immunization of stromal cell targeting fibroblast activation protein providing immunotherapy to breast cancer mouse model.

    Science.gov (United States)

    Meng, Mingyao; Wang, Wenju; Yan, Jun; Tan, Jing; Liao, Liwei; Shi, Jianlin; Wei, Chuanyu; Xie, Yanhua; Jin, Xingfang; Yang, Li; Jin, Qing; Zhu, Huirong; Tan, Weiwei; Yang, Fang; Hou, Zongliu

    2016-08-01

    Unlike heterogeneous tumor cells, cancer-associated fibroblasts (CAF) are genetically more stable which serve as a reliable target for tumor immunotherapy. Fibroblast activation protein (FAP) which is restrictively expressed in tumor cells and CAF in vivo and plays a prominent role in tumor initiation, progression, and metastasis can function as a tumor rejection antigen. In the current study, we have constructed artificial FAP(+) stromal cells which mimicked the FAP(+) CAF in vivo. We immunized a breast cancer mouse model with FAP(+) stromal cells to perform immunotherapy against FAP(+) cells in the tumor microenvironment. By forced expression of FAP, we have obtained FAP(+) stromal cells whose phenotype was CD11b(+)/CD34(+)/Sca-1(+)/FSP-1(+)/MHC class I(+). Interestingly, proliferation capacity of the fibroblasts was significantly enhanced by FAP. In the breast cancer-bearing mouse model, vaccination with FAP(+) stromal cells has significantly inhibited the growth of allograft tumor and reduced lung metastasis indeed. Depletion of T cell assays has suggested that both CD4(+) and CD8(+) T cells were involved in the tumor cytotoxic immune response. Furthermore, tumor tissue from FAP-immunized mice revealed that targeting FAP(+) CAF has induced apoptosis and decreased collagen type I and CD31 expression in the tumor microenvironment. These results implicated that immunization with FAP(+) stromal cells led to the disruption of the tumor microenvironment. Our study may provide a novel strategy for immunotherapy of a broad range of cancer.

  5. OpenClimateGIS - A Web Service Providing Climate Model Data in Commonly Used Geospatial Formats

    Science.gov (United States)

    Erickson, T. A.; Koziol, B. W.; Rood, R. B.

    2011-12-01

    The goal of the OpenClimateGIS project is to make climate model datasets readily available in commonly used, modern geospatial formats used by GIS software, browser-based mapping tools, and virtual globes.The climate modeling community typically stores climate data in multidimensional gridded formats capable of efficiently storing large volumes of data (such as netCDF, grib) while the geospatial community typically uses flexible vector and raster formats that are capable of storing small volumes of data (relative to the multidimensional gridded formats). OpenClimateGIS seeks to address this difference in data formats by clipping climate data to user-specified vector geometries (i.e. areas of interest) and translating the gridded data on-the-fly into multiple vector formats. The OpenClimateGIS system does not store climate data archives locally, but rather works in conjunction with external climate archives that expose climate data via the OPeNDAP protocol. OpenClimateGIS provides a RESTful API web service for accessing climate data resources via HTTP, allowing a wide range of applications to access the climate data.The OpenClimateGIS system has been developed using open source development practices and the source code is publicly available. The project integrates libraries from several other open source projects (including Django, PostGIS, numpy, Shapely, and netcdf4-python).OpenClimateGIS development is supported by a grant from NOAA's Climate Program Office.

  6. Exploring the Group Prenatal Care Model: A Critical Review of the Literature

    Science.gov (United States)

    Thielen, Kathleen

    2012-01-01

    Few studies have compared perinatal outcomes between individual prenatal care and group prenatal care. A critical review of research articles that were published between 1998 and 2009 and involved participants of individual and group prenatal care was conducted. Two middle range theories, Pender’s health promotion model and Swanson’s theory of caring, were blended to enhance conceptualization of the relationship between pregnant women and the group prenatal care model. Among the 17 research studies that met inclusion criteria for this critical review, five examined gestational age and birth weight with researchers reporting longer gestations and higher birth weights in infants born to mothers participating in group prenatal care, especially in the preterm birth population. Current evidence demonstrates that nurse educators and leaders should promote group prenatal care as a potential method of improving perinatal outcomes within the pregnant population. PMID:23997549

  7. Exploring the group prenatal care model: a critical review of the literature.

    Science.gov (United States)

    Thielen, Kathleen

    2012-01-01

    Few studies have compared perinatal outcomes between individual prenatal care and group prenatal care. A critical review of research articles that were published between 1998 and 2009 and involved participants of individual and group prenatal care was conducted. Two middle range theories, Pender's health promotion model and Swanson's theory of caring, were blended to enhance conceptualization of the relationship between pregnant women and the group prenatal care model. Among the 17 research studies that met inclusion criteria for this critical review, five examined gestational age and birth weight with researchers reporting longer gestations and higher birth weights in infants born to mothers participating in group prenatal care, especially in the preterm birth population. Current evidence demonstrates that nurse educators and leaders should promote group prenatal care as a potential method of improving perinatal outcomes within the pregnant population.

  8. Monte Carlo method for critical systems in infinite volume: The planar Ising model.

    Science.gov (United States)

    Herdeiro, Victor; Doyon, Benjamin

    2016-10-01

    In this paper we propose a Monte Carlo method for generating finite-domain marginals of critical distributions of statistical models in infinite volume. The algorithm corrects the problem of the long-range effects of boundaries associated to generating critical distributions on finite lattices. It uses the advantage of scale invariance combined with ideas of the renormalization group in order to construct a type of "holographic" boundary condition that encodes the presence of an infinite volume beyond it. We check the quality of the distribution obtained in the case of the planar Ising model by comparing various observables with their infinite-plane prediction. We accurately reproduce planar two-, three-, and four-point of spin and energy operators. We also define a lattice stress-energy tensor, and numerically obtain the associated conformal Ward identities and the Ising central charge.

  9. Modelling Water Uptake Provides a New Perspective on Grass and Tree Coexistence.

    Directory of Open Access Journals (Sweden)

    Michael G Mazzacavallo

    Full Text Available Root biomass distributions have long been used to infer patterns of resource uptake. These patterns are used to understand plant growth, plant coexistence and water budgets. Root biomass, however, may be a poor indicator of resource uptake because large roots typically do not absorb water, fine roots do not absorb water from dry soils and roots of different species can be difficult to differentiate. In a sub-tropical savanna, Kruger Park, South Africa, we used a hydrologic tracer experiment to describe the abundance of active grass and tree roots across the soil profile. We then used this tracer data to parameterize a water movement model (Hydrus 1D. The model accounted for water availability and estimated grass and tree water uptake by depth over a growing season. Most root biomass was found in shallow soils (0-20 cm and tracer data revealed that, within these shallow depths, half of active grass roots were in the top 12 cm while half of active tree roots were in the top 21 cm. However, because shallow soils provided roots with less water than deep soils (20-90 cm, the water movement model indicated that grass and tree water uptake was twice as deep as would be predicted from root biomass or tracer data alone: half of grass and tree water uptake occurred in the top 23 and 43 cm, respectively. Niche partitioning was also greater when estimated from water uptake rather than tracer uptake. Contrary to long-standing assumptions, shallow grass root distributions absorbed 32% less water than slightly deeper tree root distributions when grasses and trees were assumed to have equal water demands. Quantifying water uptake revealed deeper soil water uptake, greater niche partitioning and greater benefits of deep roots than would be estimated from root biomass or tracer uptake data alone.

  10. Biochemical markers and the FDA Critical Path: how biomarkers may contribute to the understanding of pathophysiology and provide unique and necessary tools for drug development

    DEFF Research Database (Denmark)

    Karsdal, M A; Henriksen, K; Leeming, D J

    2009-01-01

    The aim of this review is to discuss the potential usefulness of a novel class of biochemical markers, neoepitopes, in the context of the US Food and Drug Administration (FDA) Critical Path Initiative, which emphasizes biomarkers of safety and efficacy as areas of pivotal interest. Examples...

  11. Observation and characterization of flow in critical sections of a horizontal pressurized gating system using water models

    Directory of Open Access Journals (Sweden)

    Jaiganesh Venkataramani

    2013-07-01

    Full Text Available This work is concerned with the hydraulics and flow characterization in a pressurized, horizontal gating system with multiple ingates attached to a plate mold, using transparent water models. Runners with two different aspect ratios (w/h = 0.5 and 2 and four different types of ingates (rectangular, convergent, divergent and venturi were examined for their influence on flow behavior. Flow behavior was visualized using a high speed camera capable of capturing images up to 10,000 frames per second. Real time experimentation with a few runner – ingate combinations were carried out to validate the usefulness of water models in predicting the filling behavior. Comparison of the approaches provided useful insights into the filling behavior in critical sections of the flow passages as well as the utility of water models towards understanding of the filling behavior during real time casting.

  12. Critical temperature for a model quasi-one-dimensional disordered superconductor

    Science.gov (United States)

    Lin, Yi; Yi, Xiao; Kai-lun, Yao

    1993-06-01

    With the help of the decimation ansatz of the renormlization group, the dependence of critical temperature on a transverse magnetic field is calculated analytically for a quasi-one-dimensional disordered superconductor model, based on the de Gennes-Skal-Shklovskii (dGSS) picture of the large cluster in a percolation system. Our results are in good agreement with those given by Halley's scaling theory.

  13. A Market Model for Evaluating Technologies That Impact Critical-Material Intensity

    Science.gov (United States)

    Iyer, Ananth V.; Vedantam, Aditya

    2016-07-01

    A recent Critical Materials Strategy report highlighted the supply chain risk associated with neodymium and dysprosium, which are used in the manufacturing of neodymium-iron-boron permanent magnets (PM). In response, the Critical Materials Institute is developing innovative strategies to increase and diversify primary production, develop substitutes, reduce material intensity and recycle critical materials. Our goal in this paper is to propose an economic model to quantify the impact of one of these strategies, material intensity reduction. Technologies that reduce material intensity impact the economics of magnet manufacturing in multiple ways because of: (1) the lower quantity of critical material required per unit PM, (2) more efficient use of limited supply, and (3) the potential impact on manufacturing cost. However, the net benefit of these technologies to a magnet manufacturer is an outcome of an internal production decision subject to market demand characteristics, availability and resource constraints. Our contribution in this paper shows how a manufacturer's production economics moves from a region of being supply-constrained, to a region enabling the market optimal production quantity, to a region being constrained by resources other than critical materials, as the critical material intensity changes. Key insights for engineers and material scientists are: (1) material intensity reduction can have a significant market impact, (2) benefits to manufacturers are non-linear in the material intensity reduction, (3) there exists a threshold value for material intensity reduction that can be calculated for any target PM application, and (4) there is value for new intellectual property (IP) when existing manufacturing technology is IP-protected.

  14. Towards a conceptual model of online peer feedback: What about the provider?

    OpenAIRE

    Van Popta, Esther; Kral, Marijke; Camp, Gino; Martens, Rob; Simons, P.R.

    2018-01-01

    This paper reviews studies of peer feedback from the novel perspective of the providers of that feedback. The possible learning benefits of providing peer feedback in online learning have not been extensively studied. The goal of this study was therefore to explore the process of providing online peer feedback as a learning activity for the provider. We concluded that (1) providing online peer feedback has several potential learning benefits for the provider; (2) when providing online peer fe...

  15. Effect of caffeine intake on critical power model parameters determined on a cycle ergometer

    Directory of Open Access Journals (Sweden)

    Marcus Vinicius Machado

    2010-01-01

    Full Text Available The aim of this study was to evaluate the effect of caffeine intake on critical power model parameters determined on a cycle ergometer. Eight male subjects participated in this study. A double-blind protocol consisting of the intake of pure caffeine (6 mg/kg or placebo (maltodextrin 60 min before testing was used. Subjects were submitted to four constant-load tests on a cycle ergometer. These tests were conducted randomly in the caffeine and placebo groups [checar] at intensities of 80, 90, 100 and 110% maximum power at a rate of 70 rpm until exhaustion to determine the critical power. As a criterion for stopping the test was adopted any rate fall without recovery by more than five seconds. The critical power and anaerobic work capacity were obtained by nonlinear regression and fitting of the curve to a hyperbolic power-time model. The Shapiro-Wilk test and paired Student t-test were used for statistical analysis. No significant differences in critical power were observed between the caffeine and placebo groups (192.9 ± 31.3 vs 197.7 ± 29.4 W, respectively. The anaerobic work capacity was significantly higher in the caffeine group (20.1 ± 5.2 vs 16.3 ± 4.2 W, p< 0.01. A high association (r2 was observed between the caffeine and placebo conditions (0.98 ± 0.02 and 0.99 ± 0.0, respectively. We conclude that caffeine intake did not improve critical power performance but increased anaerobic work capacity by influencing performance at loads of higher intensity and shorter duration.

  16. Risk factors associated with iatrogenic opioid and benzodiazepine withdrawal in critically ill pediatric patients: a systematic review and conceptual model.

    Science.gov (United States)

    Best, Kaitlin M; Boullata, Joseph I; Curley, Martha A Q

    2015-02-01

    Analgesia and sedation are common therapies in pediatric critical care, and rapid titration of these medications is associated with iatrogenic withdrawal syndrome. We performed a systematic review of the literature to identify all common and salient risk factors associated with iatrogenic withdrawal syndrome and build a conceptual model of iatrogenic withdrawal syndrome risk in critically ill pediatric patients. Multiple databases, including PubMed/Medline, EMBASE, CINAHL, and the Cochrane Central Registry of Clinical Trials, were searched using relevant terms from January 1, 1980, to August 1, 2014. Articles were included if they were published in English and discussed iatrogenic withdrawal syndrome following either opioid or benzodiazepine therapy in children in acute or intensive care settings. Articles were excluded if subjects were neonates born to opioid- or benzodiazepine-dependent mothers, children diagnosed as substance abusers, or subjects with cancer-related pain; if data about opioid or benzodiazepine treatment were not specified; or if primary data were not reported. In total, 1,395 articles were evaluated, 33 of which met the inclusion criteria. To facilitate analysis, all opioid and/or benzodiazepine doses were converted to morphine or midazolam equivalents, respectively. A table of evidence was developed for qualitative analysis of common themes, providing a framework for the construction of a conceptual model. The strongest risk factors associated with iatrogenic withdrawal syndrome include duration of therapy and cumulative dose. Additionally, evidence exists linking patient, process, and system factors in the development of iatrogenic withdrawal syndrome. Most articles were prospective observational or interventional studies. Given the state of existing evidence, well-designed prospective studies are required to better characterize iatrogenic withdrawal syndrome in critically ill pediatric patients. This review provides data to support the

  17. Information processing occurs via critical avalanches in a model of the primary visual cortex

    Science.gov (United States)

    Bortolotto, G. S.; Girardi-Schappo, M.; Gonsalves, J. J.; Pinto, L. T.; Tragtenberg, M. H. R.

    2016-01-01

    We study a new biologically motivated model for the Macaque monkey primary visual cortex which presents power-law avalanches after a visual stimulus. The signal propagates through all the layers of the model via avalanches that depend on network structure and synaptic parameter. We identify four different avalanche profiles as a function of the excitatory postsynaptic potential. The avalanches follow a size-duration scaling relation and present critical exponents that match experiments. The structure of the network gives rise to a regime of two characteristic spatial scales, one of which vanishes in the thermodynamic limit.

  18. Influence of Selective Edge Removal and Refractory Period in a Self-Organized Critical Neuron Model

    International Nuclear Information System (INIS)

    Lin Min; Gang, Zhao; Chen Tianlun

    2009-01-01

    A simple model for a set of integrate-and-fire neurons based on the weighted network is introduced. By considering the neurobiological phenomenon in brain development and the difference of the synaptic strength, we construct weighted networks develop with link additions and followed by selective edge removal. The network exhibits the small-world and scale-free properties with high network efficiency. The model displays an avalanche activity on a power-law distribution. We investigate the effect of selective edge removal and the neuron refractory period on the self-organized criticality of the system. (condensed matter: structural, mechanical, and thermal properties)

  19. Input-dependent wave attenuation in a critically-balanced model of cortex.

    Directory of Open Access Journals (Sweden)

    Xiao-Hu Yan

    Full Text Available A number of studies have suggested that many properties of brain activity can be understood in terms of critical systems. However it is still not known how the long-range susceptibilities characteristic of criticality arise in the living brain from its local connectivity structures. Here we prove that a dynamically critically-poised model of cortex acquires an infinitely-long ranged susceptibility in the absence of input. When an input is presented, the susceptibility attenuates exponentially as a function of distance, with an increasing spatial attenuation constant (i.e., decreasing range the larger the input. This is in direct agreement with recent results that show that waves of local field potential activity evoked by single spikes in primary visual cortex of cat and macaque attenuate with a characteristic length that also increases with decreasing contrast of the visual stimulus. A susceptibility that changes spatial range with input strength can be thought to implement an input-dependent spatial integration: when the input is large, no additional evidence is needed in addition to the local input; when the input is weak, evidence needs to be integrated over a larger spatial domain to achieve a decision. Such input-strength-dependent strategies have been demonstrated in visual processing. Our results suggest that input-strength dependent spatial integration may be a natural feature of a critically-balanced cortical network.

  20. Hydrological modeling in alpine catchments: sensing the critical parameters towards an efficient model calibration.

    Science.gov (United States)

    Achleitner, S; Rinderer, M; Kirnbauer, R

    2009-01-01

    For the Tyrolean part of the river Inn, a hybrid model for flood forecast has been set up and is currently in its test phase. The system is a hybrid system which comprises of a hydraulic 1D model for the river Inn, and the hydrological models HQsim (Rainfall-runoff-discharge model) and the snow and ice melt model SES for modeling the rainfall runoff form non-glaciated and glaciated tributary catchment respectively. Within this paper the focus is put on the hydrological modeling of the totally 49 connected non-glaciated catchments realized with the software HQsim. In the course of model calibration, the identification of the most sensitive parameters is important aiming at an efficient calibration procedure. The indicators used for explaining the parameter sensitivities were chosen specifically for the purpose of flood forecasting. Finally five model parameters could be identified as being sensitive for model calibration when aiming for a well calibrated model for flood conditions. In addition two parameters were identified which are sensitive in situations where the snow line plays an important role.

  1. Estimated Nutritive Value of Low-Price Model Lunch Sets Provided to Garment Workers in Cambodia.

    Science.gov (United States)

    Makurat, Jan; Pillai, Aarati; Wieringa, Frank T; Chamnan, Chhoun; Krawinkel, Michael B

    2017-07-21

    The establishment of staff canteens is expected to improve the nutritional situation of Cambodian garment workers. The objective of this study is to assess the nutritive value of low-price model lunch sets provided at a garment factory in Phnom Penh, Cambodia. Exemplary lunch sets were served to female workers through a temporary canteen at a garment factory in Phnom Penh. Dish samples were collected repeatedly to examine mean serving sizes of individual ingredients. Food composition tables and NutriSurvey software were used to assess mean amounts and contributions to recommended dietary allowances (RDAs) or adequate intake of energy, macronutrients, dietary fiber, vitamin C (VitC), iron, vitamin A (VitA), folate and vitamin B12 (VitB12). On average, lunch sets provided roughly one third of RDA or adequate intake of energy, carbohydrates, fat and dietary fiber. Contribution to RDA of protein was high (46% RDA). The sets contained a high mean share of VitC (159% RDA), VitA (66% RDA), and folate (44% RDA), but were low in VitB12 (29% RDA) and iron (20% RDA). Overall, lunches satisfied recommendations of caloric content and macronutrient composition. Sets on average contained a beneficial amount of VitC, VitA and folate. Adjustments are needed for a higher iron content. Alternative iron-rich foods are expected to be better suited, compared to increasing portions of costly meat/fish components. Lunch provision at Cambodian garment factories holds the potential to improve food security of workers, approximately at costs of <1 USD/person/day at large scale. Data on quantitative total dietary intake as well as physical activity among workers are needed to further optimize the concept of staff canteens.

  2. Estimated Nutritive Value of Low-Price Model Lunch Sets Provided to Garment Workers in Cambodia

    Directory of Open Access Journals (Sweden)

    Jan Makurat

    2017-07-01

    Full Text Available Background: The establishment of staff canteens is expected to improve the nutritional situation of Cambodian garment workers. The objective of this study is to assess the nutritive value of low-price model lunch sets provided at a garment factory in Phnom Penh, Cambodia. Methods: Exemplary lunch sets were served to female workers through a temporary canteen at a garment factory in Phnom Penh. Dish samples were collected repeatedly to examine mean serving sizes of individual ingredients. Food composition tables and NutriSurvey software were used to assess mean amounts and contributions to recommended dietary allowances (RDAs or adequate intake of energy, macronutrients, dietary fiber, vitamin C (VitC, iron, vitamin A (VitA, folate and vitamin B12 (VitB12. Results: On average, lunch sets provided roughly one third of RDA or adequate intake of energy, carbohydrates, fat and dietary fiber. Contribution to RDA of protein was high (46% RDA. The sets contained a high mean share of VitC (159% RDA, VitA (66% RDA, and folate (44% RDA, but were low in VitB12 (29% RDA and iron (20% RDA. Conclusions: Overall, lunches satisfied recommendations of caloric content and macronutrient composition. Sets on average contained a beneficial amount of VitC, VitA and folate. Adjustments are needed for a higher iron content. Alternative iron-rich foods are expected to be better suited, compared to increasing portions of costly meat/fish components. Lunch provision at Cambodian garment factories holds the potential to improve food security of workers, approximately at costs of <1 USD/person/day at large scale. Data on quantitative total dietary intake as well as physical activity among workers are needed to further optimize the concept of staff canteens.

  3. Inducing self-organized criticality in a network toy model by neighborhood assortativity.

    Science.gov (United States)

    Allen-Perkins, Alfonso; Galeano, Javier; Pastor, Juan Manuel

    2016-11-01

    Complex networks are a recent type of framework used to study complex systems with many interacting elements, such as self-organized criticality (SOC). The network nodes' tendency to link to other nodes of similar type is characterized by assortative mixing. Real networks exhibit assortative mixing by vertex degree, however, typical random network models, such as the Erdős-Rényi or the Barabási-Albert model, show no assortative arrangements. In this paper we introduce the notion of neighborhood assortativity as the tendency of a node to belong to a community (its neighborhood) showing an average property similar to its own. Imposing neighborhood assortative mixing by degree in a network toy model, SOC dynamics can be found. These dynamics are driven only by the network topology. The long-range correlations resulting from criticality have been characterized by means of fluctuation analysis and show an anticorrelation in the node's activity. The model contains only one parameter and its statistics plots for different values of the parameter can be collapsed into a single curve. The simplicity of the model allows us to perform numerical simulations and also to study analytically the statistics for a specific value of the parameter, making use of the Markov chains.

  4. SU-E-T-170: Characterization of the Location, Extent, and Proximity to Critical Structures of Target Volumes Provides Detail for Improved Outcome Predictions Among Pancreatic Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Z; Moore, J; Rosati, L; Mian, O; Narang, A; Herman, J; McNutt, T [Johns Hopkins University, Baltimore, MD (United States)

    2015-06-15

    Purpose: In radiotherapy, size, location and proximity of the target to critical structures influence treatment decisions. It has been shown that proximity of the target predicts dosimetric sparing of critical structures. In addition to dosimetry, precise location of disease has further implications such as tumor invasion, or proximity to major arteries that inhibit surgery. Knowledge of which patients can be converted to surgical candidates by radiation may have high impact on future treat/no-treat decisions. We propose a method to improve our characterization of the location of pancreatic cancer and treatment volume extent with respect to nearby arteries with the goal of developing features to improve clinical predictions and decisions. Methods: Oncospace is a local learning health system that systematically captures clinical outcomes and all aspects of radiotherapy treatment plans, including overlap volume histograms (OVH) – a measure of spatial relationships between two structures. Minimum and maximum distances of PTV and OARs based on OVH, PTV volume, anatomic location by ICD-9 code, and surgical outcome were queried. Normalized distance to center from the left and right kidney was calculated to indicate tumor location and laterality. Distance to critical arteries (celiac, superior mesenteric, common hepatic) is validated by surgical status (borderline resectable, locally advanced converted to resectable). Results: There were 205 pancreas stereotactic body radiotherapy patients treated from 2009–2015 queried. Location/laterality of tumor based on kidney OVH show strong trends between location by OVH and by ICD-9. Compared to the locally advanced group, the borderline resectable group showed larger geometrical distance from critical arteries (p=0.03). Conclusion: Our platform enabled analysis of shape/size-location relationships. These data suggest that PTV volume and attention to distance between PTVs and surrounding OARs and major arteries may be

  5. SU-E-T-170: Characterization of the Location, Extent, and Proximity to Critical Structures of Target Volumes Provides Detail for Improved Outcome Predictions Among Pancreatic Cancer Patients

    International Nuclear Information System (INIS)

    Cheng, Z; Moore, J; Rosati, L; Mian, O; Narang, A; Herman, J; McNutt, T

    2015-01-01

    Purpose: In radiotherapy, size, location and proximity of the target to critical structures influence treatment decisions. It has been shown that proximity of the target predicts dosimetric sparing of critical structures. In addition to dosimetry, precise location of disease has further implications such as tumor invasion, or proximity to major arteries that inhibit surgery. Knowledge of which patients can be converted to surgical candidates by radiation may have high impact on future treat/no-treat decisions. We propose a method to improve our characterization of the location of pancreatic cancer and treatment volume extent with respect to nearby arteries with the goal of developing features to improve clinical predictions and decisions. Methods: Oncospace is a local learning health system that systematically captures clinical outcomes and all aspects of radiotherapy treatment plans, including overlap volume histograms (OVH) – a measure of spatial relationships between two structures. Minimum and maximum distances of PTV and OARs based on OVH, PTV volume, anatomic location by ICD-9 code, and surgical outcome were queried. Normalized distance to center from the left and right kidney was calculated to indicate tumor location and laterality. Distance to critical arteries (celiac, superior mesenteric, common hepatic) is validated by surgical status (borderline resectable, locally advanced converted to resectable). Results: There were 205 pancreas stereotactic body radiotherapy patients treated from 2009–2015 queried. Location/laterality of tumor based on kidney OVH show strong trends between location by OVH and by ICD-9. Compared to the locally advanced group, the borderline resectable group showed larger geometrical distance from critical arteries (p=0.03). Conclusion: Our platform enabled analysis of shape/size-location relationships. These data suggest that PTV volume and attention to distance between PTVs and surrounding OARs and major arteries may be

  6. Developing Critical Thinking of Middle School Students using Problem Based Learning 4 Core Areas (PBL4C) Model

    Science.gov (United States)

    Haridza, R.; E Irving, K.

    2017-02-01

    Traditional methods such as rote learning and memorization in teaching science create passive students in science classrooms. The impact of this continuous action for many decades is inactive learners who cannot develop higher order thinking skills. Based on the performance test, students’ critical thinking skill in Public Middle School 3 Pontianak was in low level although their achievement score were higher than school standards. The purpose of this study is to develop critical thinking skills of middle school students using Problem Based Learning 4 Core Areas (PBL4C). The design of this research is classroom action research with two cycles. Data has been collected using observation checklist, rating scale, self and peer assessment. Research findings reveal that students experience development from 11.11% to 88.45% in identifying the problem correctly, 37.03% to 76.92% for sub skills distinguish knowledge and opinion, 18.51% to 65.38% for sub skills providing possible solution, 22.22% to 69.23% for sub skills making decision, and 11.11% to 69.23% for sub skills identifying the impact of the implementation of their solution. In conclusion, the findings indicate that development of students’ critical thinking skills occurs when PBL4C model applied in science classroom. These findings suggest that teachers should act as facilitator in a classroom as well as should provide meaningful learning resources that can benefit students’ critical thinking skills. On the other hand, students should practice constantly to offer a sharp, accurate and appropriate solution.

  7. A mathematical model for predicting glucose levels in critically-ill patients: the PIGnOLI model

    Directory of Open Access Journals (Sweden)

    Zhongheng Zhang

    2015-06-01

    Full Text Available Background and Objectives. Glycemic control is of paramount importance in the intensive care unit. Presently, several BG control algorithms have been developed for clinical trials, but they are mostly based on experts’ opinion and consensus. There are no validated models predicting how glucose levels will change after initiating of insulin infusion in critically ill patients. The study aimed to develop an equation for initial insulin dose setting.Methods. A large critical care database was employed for the study. Linear regression model fitting was employed. Retested blood glucose was used as the independent variable. Insulin rate was forced into the model. Multivariable fractional polynomials and interaction terms were used to explore the complex relationships among covariates. The overall fit of the model was examined by using residuals and adjusted R-squared values. Regression diagnostics were used to explore the influence of outliers on the model.Main Results. A total of 6,487 ICU admissions requiring insulin pump therapy were identified. The dataset was randomly split into two subsets at 7 to 3 ratio. The initial model comprised fractional polynomials and interactions terms. However, this model was not stable by excluding several outliers. I fitted a simple linear model without interaction. The selected prediction model (Predicting Glucose Levels in ICU, PIGnOLI included variables of initial blood glucose, insulin rate, PO volume, total parental nutrition, body mass index (BMI, lactate, congestive heart failure, renal failure, liver disease, time interval of BS recheck, dextrose rate. Insulin rate was significantly associated with blood glucose reduction (coefficient: −0.52, 95% CI [−1.03, −0.01]. The parsimonious model was well validated with the validation subset, with an adjusted R-squared value of 0.8259.Conclusion. The study developed the PIGnOLI model for the initial insulin dose setting. Furthermore, experimental study is

  8. Could implantable cardioverter defibrillators provide a human model supporting the learned helplessness theory of depression?

    Science.gov (United States)

    Goodman, M; Hess, B

    1999-01-01

    Affective symptoms were examined retrospectively in 25 patients following placement of implantable cardioverter defibrillators (ICD) which can produce intermittent shocks without warning in response to cardiac ventricular arrhythmias. The number of ICD random, uncontrollable discharge shocks and pre-ICD history of psychological distress (i.e., depression and/or anxiety) were documented in all patients using a demographics questionnaire and a standardized behavioral/psychological symptoms questionnaire (i.e., Symptom Checklist-90 Revised). ICD patients were dichotomized into two groups: those without a history of psychological distress prior to ICD (n = 18) and those with a history of psychological distress prior to ICD (n = 7). In ICD patients without a prior history, results indicated that quantity of ICD discharge shocks was significantly predictive of current reported depression (r = 0.45, p = 0.03) and current reported anxiety (r = 0.51, p = 0.02). Conversely, in patients with a reported history of psychological distress, there was no significant relationship found between quantity of discharge shocks and current reported depression or anxiety. This study may provide evidence in support of a human model of learned helplessness in that it supports the notion that exposure to an unavoidable and inescapable aversive stimulus was found to be related to patients' reported depression. Further studies may wish to prospectively consider a larger sample as well as a more comprehensive assessment of premorbid psychological symptoms.

  9. Model for a reproducible curriculum infrastructure to provide international nurse anesthesia continuing education.

    Science.gov (United States)

    Collins, Shawn Bryant

    2011-12-01

    There are no set standards for nurse anesthesia education in developing countries, yet one of the keys to the standards in global professional practice is competency assurance for individuals. Nurse anesthetists in developing countries have difficulty obtaining educational materials. These difficulties include, but are not limited to, financial constraints, lack of anesthesia textbooks, and distance from educational sites. There is increasing evidence that the application of knowledge in developing countries is failing. One reason is that many anesthetists in developing countries are trained for considerably less than acceptable time periods and are often supervised by poorly trained practitioners, who then pass on less-than-desirable practice skills, thus exacerbating difficulties. Sustainability of development can come only through anesthetists who are both well trained and able to pass on their training to others. The international nurse anesthesia continuing education project was developed in response to the difficulty that nurse anesthetists in developing countries face in accessing continuing education. The purpose of this project was to develop a nonprofit, volunteer-based model for providing nurse anesthesia continuing education that can be reproduced and used in any developing country.

  10. Improving Students’ Argumentation Style Ability in Writing Essay through Discourse Analysis Model Critical Thinking Map Oriented

    Directory of Open Access Journals (Sweden)

    R. Panca Pertiwi Hidayati

    2017-03-01

    Full Text Available Students’ ability in writing anessay, as one of language skills which can improve the creativity in language, is a serious problem that should be investigated by a deep research. Besides for showing that language as a thinking tool, writing competence can be seen as a product if we take a look from critical thinking ability measurement aspect and also as a process if we take a look at the individual development itself aspect. One of indicator for measuring the students’ critical is by the ability in delivering their argumentation style which is showed in their essay. The goal of this research is obtaining the objective discourse analysis model critical thinking map oriented in improving students’ argumentation style skills in writing anessay, hence can be used as a modelling for the growing of students’ creativity in a variety of writing skills. Based on paired-samples t test, the pre-test/post-test paired-sample is significant, because the significance (2-tailed is less than 0.05 in the standard of 95%. This is mean, there is a real difference between the ability before and after getting the treatment. The sample’s ability after getting the treatment is better than before. As well as if be compared with control class, experiment class shows the significant superiority for all aspects of essay writing assessment.

  11. Application of GI-TPS Model to Skills Critical Thinking and Self Efficacy

    Directory of Open Access Journals (Sweden)

    Rusmansyah

    2017-12-01

    Full Text Available This research aims to know the: (1 the difference in critical thinking ability of students (2 difference in the results of learning (cognitive, affective, psychomotor (3 self efficacy of students (4 student response towards the learning model GI-TPS (Guided Inquiry-Think Pair Share on the hydrolysis of salt. This research use the pretest-posttest design nonequivalent control group design. A sample of 50 research students, namely class XI IPA 2 and XI IPA 3. Samples taken with purposive sampling technique. Engineering data collection using the test the critical thinking ability, cognitive learning results, observations, and the now. Analytical techniques descriptive analyses using data and analysis inferensial (test, test the normality of its homogeneity, and t-test. The results of this study suggest that (1 there is a difference significant critical thinking abilities (2 there is a difference in learning outcomes (cognitive, affective, psychomotor a significant (3 students who have self efficacy. (4 the students gave positive response towards the learning model GI-TPS material on the hydrolysis of salt.

  12. The role of infection models and PK/PD modelling for optimising care of critically ill patients with severe infections.

    Science.gov (United States)

    Tängdén, T; Ramos Martín, V; Felton, T W; Nielsen, E I; Marchand, S; Brüggemann, R J; Bulitta, J B; Bassetti, M; Theuretzbacher, U; Tsuji, B T; Wareham, D W; Friberg, L E; De Waele, J J; Tam, V H; Roberts, Jason A

    2017-07-01

    Critically ill patients with severe infections are at high risk of suboptimal antimicrobial dosing. The pharmacokinetics (PK) and pharmacodynamics (PD) of antimicrobials in these patients differ significantly from the patient groups from whose data the conventional dosing regimens were developed. Use of such regimens often results in inadequate antimicrobial concentrations at the site of infection and is associated with poor patient outcomes. In this article, we describe the potential of in vitro and in vivo infection models, clinical pharmacokinetic data and pharmacokinetic/pharmacodynamic models to guide the design of more effective antimicrobial dosing regimens. Individualised dosing, based on population PK models and patient factors (e.g. renal function and weight) known to influence antimicrobial PK, increases the probability of achieving therapeutic drug exposures while at the same time avoiding toxic concentrations. When therapeutic drug monitoring (TDM) is applied, early dose adaptation to the needs of the individual patient is possible. TDM is likely to be of particular importance for infected critically ill patients, where profound PK changes are present and prompt appropriate antibiotic therapy is crucial. In the light of the continued high mortality rates in critically ill patients with severe infections, a paradigm shift to refined dosing strategies for antimicrobials is warranted to enhance the probability of achieving drug concentrations that increase the likelihood of clinical success.

  13. Critical points of the Bose–Hubbard model with three-body local interaction

    Energy Technology Data Exchange (ETDEWEB)

    Avila, C.A.; Franco, R. [Departamento de Física, Universidad Nacional de Colombia, A.A. 5997, Bogotá (Colombia); Souza, A.M.C. [Departamento de Física, Universidade Federal de Sergipe, 49100-000 São Cristovão, SE (Brazil); Figueira, M.S. [Instituto de Física, Universidade Federal Fluminense, Av. Litorânea s/n, 24210-346 Niterói, Rio de Janeiro (Brazil); Silva-Valencia, J., E-mail: jsilvav@unal.edu.co [Departamento de Física, Universidad Nacional de Colombia, A.A. 5997, Bogotá (Colombia)

    2014-09-12

    Using the density matrix renormalization group method, we study a one-dimensional system of bosons that interact with a local three-body term. We calculate the phase diagram for higher densities, where the Mott insulator lobes are surrounded by the superfluid phase. We also show that the Mott insulator lobes always grow as a function of the density. The critical points of the Kosterlitz–Thouless transitions were determined through the von Neumann block entropy, and its dependence on the density is given by a power law with a negative exponent. - Highlights: • We studied the Bose–Hubbard model with a local three-body interaction term. • We show that the Mott insulator lobes always grow as a function of the density. • We found a power law dependence of the critical point position with the density.

  14. Classical dynamics of the Abelian Higgs model from the critical point and beyond

    Directory of Open Access Journals (Sweden)

    G.C. Katsimiga

    2015-09-01

    Full Text Available We present two different families of solutions of the U(1-Higgs model in a (1+1 dimensional setting leading to a localization of the gauge field. First we consider a uniform background (the usual vacuum, which corresponds to the fully higgsed-superconducting phase. Then we study the case of a non-uniform background in the form of a domain wall which could be relevantly close to the critical point of the associated spontaneous symmetry breaking. For both cases we obtain approximate analytical nodeless and nodal solutions for the gauge field resulting as bound states of an effective Pöschl–Teller potential created by the scalar field. The two scenaria differ only in the scale of the characteristic localization length. Numerical simulations confirm the validity of the obtained analytical solutions. Additionally we demonstrate how a kink may be used as a mediator driving the dynamics from the critical point and beyond.

  15. Critical Analysis of Underground Coal Gasification Models. Part II: Kinetic and Computational Fluid Dynamics Models

    Directory of Open Access Journals (Sweden)

    Alina Żogała

    2014-01-01

    Originality/value: This paper presents state of art in the field of coal gasification modeling using kinetic and computational fluid dynamics approach. The paper also presents own comparative analysis (concerned with mathematical formulation, input data and parameters, basic assumptions, obtained results etc. of the most important models of underground coal gasification.

  16. Critical Evaluation of Two Models for Entrepreneurial Education: An Improved Model through Integration

    Science.gov (United States)

    Pretorius, Marius; Nieman, Gideon; van Vuuren, Jurie

    2005-01-01

    Purpose: This paper focuses on the comparison of two models for entrepreneurial education with the aim of potential integration. At this juncture when entrepreneurial development is seen as the core contributor to enhance start-ups of new ventures and hence facilitate economic growth and development, the best possible education model is required.…

  17. Model checking of safety-critical software in the nuclear engineering domain

    International Nuclear Information System (INIS)

    Lahtinen, J.; Valkonen, J.; Björkman, K.; Frits, J.; Niemelä, I.; Heljanko, K.

    2012-01-01

    Instrumentation and control (I and C) systems play a vital role in the operation of safety-critical processes. Digital programmable logic controllers (PLC) enable sophisticated control tasks which sets high requirements for system validation and verification methods. Testing and simulation have an important role in the overall verification of a system but are not suitable for comprehensive evaluation because only a limited number of system behaviors can be analyzed due to time limitations. Testing is also performed too late in the development lifecycle and thus the correction of design errors is expensive. This paper discusses the role of formal methods in software development in the area of nuclear engineering. It puts forward model checking, a computer-aided formal method for verifying the correctness of a system design model, as a promising approach to system verification. The main contribution of the paper is the development of systematic methodology for modeling safety critical systems in the nuclear domain. Two case studies are reviewed, in which we have found errors that were previously not detected. We also discuss the actions that should be taken in order to increase confidence in the model checking process.

  18. Theory analysis for Pender's health promotion model (HPM) by Barnum's criteria: a critical perspective.

    Science.gov (United States)

    Khoshnood, Zohreh; Rayyani, Masoud; Tirgari, Batool

    2018-01-13

    Background Analysis of nursing theoretical works and its role in knowledge development is presented as an essential process of critical reflection. Health promotion model (HPM) focuses on helping people achieve higher levels of well-being and identifies background factors that influence health behaviors. Objectives This paper aims to evaluate, and critique HPM by Barnum's criteria. Methods The present study reviewed books and articles derived from Proquest, PubMed, Blackwell Databases. The method of evaluation for this model is based on Barnum's criteria for analysis, application and evaluation of nursing theories. The criteria selected by Barnum embrace both internal and external criticism. Internal criticism deals with how theory components fit with each other (internal construction of theory) and external criticism deals with the way in which theory relates to the extended world (which considers theory in its relationships to human beings, nursing, and health). Results The electronic database search yielded over 27,717 titles and abstracts. Following removal of duplicates, 18,963 titles and abstracts were screened using the inclusion criteria and 1278 manuscripts were retrieved. Of these, 80 were specific to HPM and 23 to analysis of any theory in nursing relating to the aim of this article. After final selection using the inclusion criteria for this review, 28 manuscripts were identified as examining the factors contributing to theory analysis. Evaluation of health promotion theory showed that the philosophical claims and their content are consistent and clear. HPM has a logical structure and was applied to diverse age groups from differing cultures with varying health concerns. Conclusion In conclusion, among the strategies for theory critique, the Barnum approach is structured and accurate, considers theory in its relationship to human beings, community psychiatric nursing, and health. While according to Pender, nursing assessment, diagnosis and interventions

  19. Multi-scale modeling in morphogenesis: a critical analysis of the cellular Potts model.

    Directory of Open Access Journals (Sweden)

    Anja Voss-Böhme

    Full Text Available Cellular Potts models (CPMs are used as a modeling framework to elucidate mechanisms of biological development. They allow a spatial resolution below the cellular scale and are applied particularly when problems are studied where multiple spatial and temporal scales are involved. Despite the increasing usage of CPMs in theoretical biology, this model class has received little attention from mathematical theory. To narrow this gap, the CPMs are subjected to a theoretical study here. It is asked to which extent the updating rules establish an appropriate dynamical model of intercellular interactions and what the principal behavior at different time scales characterizes. It is shown that the longtime behavior of a CPM is degenerate in the sense that the cells consecutively die out, independent of the specific interdependence structure that characterizes the model. While CPMs are naturally defined on finite, spatially bounded lattices, possible extensions to spatially unbounded systems are explored to assess to which extent spatio-temporal limit procedures can be applied to describe the emergent behavior at the tissue scale. To elucidate the mechanistic structure of CPMs, the model class is integrated into a general multiscale framework. It is shown that the central role of the surface fluctuations, which subsume several cellular and intercellular factors, entails substantial limitations for a CPM's exploitation both as a mechanistic and as a phenomenological model.

  20. A model for non-equilibrium, non-homogeneous two-phase critical flow

    International Nuclear Information System (INIS)

    Bassel, Wageeh Sidrak; Ting, Daniel Kao Sun

    1999-01-01

    Critical two phase flow is a very important phenomena in nuclear reactor technology for the analysis of loss of coolant accident. Several recent papers, Lee and Shrock (1990), Dagan (1993) and Downar (1996) , among others, treat the phenomena using complex models which require heuristic parameters such as relaxation constants or interfacial transfer models. In this paper a mathematical model for one dimensional non equilibrium and non homogeneous two phase flow in constant area duct is developed. The model is constituted of three conservation equations type mass ,momentum and energy. Two important variables are defined in the model: equilibrium constant in the energy equation and the impulse function in the momentum equation. In the energy equation, the enthalpy of the liquid phase is determined by a linear interpolation function between the liquid phase enthalpy at inlet condition and the saturated liquid enthalpy at local pressure. The interpolation coefficient is the equilibrium constant. The momentum equation is expressed in terms of the impulse function. It is considered that there is slip between the liquid and vapor phases, the liquid phase is in metastable state and the vapor phase is in saturated stable state. The model is not heuristic in nature and does not require complex interface transfer models. It is proved numerically that for the critical condition the partial derivative of two phase pressure drop with respect to the local pressure or to phase velocity must be zero.This criteria is demonstrated by numerical examples. The experimental work of Fauske (1962) and Jeandey (1982) were analyzed resulting in estimated numerical values for important parameters like slip ratio, equilibrium constant and two phase frictional drop. (author)

  1. Thermo-mechanical constitutive modeling of unsaturated clays based on the critical state concepts

    Directory of Open Access Journals (Sweden)

    Saeed Tourchi

    2015-04-01

    Full Text Available A thermo-mechanical constitutive model for unsaturated clays is constructed based on the existing model for saturated clays originally proposed by the authors. The saturated clays model was formulated in the framework of critical state soil mechanics and modified Cam-clay model. The existing model has been generalized to simulate the experimentally observed behavior of unsaturated clays by introducing Bishop's stress and suction as independent stress parameters and modifying the hardening rule and yield criterion to take into account the role of suction. Also, according to previous studies, an increase in temperature causes a reduction in specific volume. A reduction in suction (wetting for a given confining stress may induce an irreversible volumetric compression (collapse. Thus an increase in suction (drying raises a specific volume i.e. the movement of normal consolidation line (NCL to higher values of void ratio. However, some experimental data confirm the assumption that this reduction is dependent on the stress level of soil element. A generalized approach considering the effect of stress level on the magnitude of clays thermal dependency in compression plane is proposed in this study. The number of modeling parameters is kept to a minimum, and they all have clear physical interpretations, to facilitate the usefulness of model for practical applications. A step-by-step procedure used for parameter calibration is also described. The model is finally evaluated using a comprehensive set of experimental data for the thermo-mechanical behavior of unsaturated soils.

  2. Spdef null mice lack conjunctival goblet cells and provide a model of dry eye.

    Science.gov (United States)

    Marko, Christina K; Menon, Balaraj B; Chen, Gang; Whitsett, Jeffrey A; Clevers, Hans; Gipson, Ilene K

    2013-07-01

    Goblet cell numbers decrease within the conjunctival epithelium in drying and cicatrizing ocular surface diseases. Factors regulating goblet cell differentiation in conjunctival epithelium are unknown. Recent data indicate that the transcription factor SAM-pointed domain epithelial-specific transcription factor (Spdef) is essential for goblet cell differentiation in tracheobronchial and gastrointestinal epithelium of mice. Using Spdef(-/-) mice, we determined that Spdef is required for conjunctival goblet cell differentiation and that Spdef(-/-) mice, which lack conjunctival goblet cells, have significantly increased corneal surface fluorescein staining and tear volume, a phenotype consistent with dry eye. Microarray analysis of conjunctival epithelium in Spdef(-/-) mice revealed down-regulation of goblet cell-specific genes (Muc5ac, Tff1, Gcnt3). Up-regulated genes included epithelial cell differentiation/keratinization genes (Sprr2h, Tgm1) and proinflammatory genes (Il1-α, Il-1β, Tnf-α), all of which are up-regulated in dry eye. Interestingly, four Wnt pathway genes were down-regulated. SPDEF expression was significantly decreased in the conjunctival epithelium of Sjögren syndrome patients with dry eye and decreased goblet cell mucin expression. These data demonstrate that Spdef is required for conjunctival goblet cell differentiation and down-regulation of SPDEF may play a role in human dry eye with goblet cell loss. Spdef(-/-) mice have an ocular surface phenotype similar to that in moderate dry eye, providing a new, more convenient model for the disease. Copyright © 2013 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  3. The EZ diffusion model provides a powerful test of simple empirical effects

    NARCIS (Netherlands)

    van Ravenzwaaij, Don; Donkin, Chris; Vandekerckhove, Joachim

    Over the last four decades, sequential accumulation models for choice response times have spread through cognitive psychology like wildfire. The most popular style of accumulator model is the diffusion model (Ratcliff Psychological Review, 85, 59–108, 1978), which has been shown to account for data

  4. Towards a conceptual model of online peer feedback: What about the provider?

    NARCIS (Netherlands)

    Van Popta, Esther; Kral, Marijke; Camp, Gino; Martens, Rob; Simons, P.R.

    2018-01-01

    This paper reviews studies of peer feedback from the novel perspective of the providers of that feedback. The possible learning benefits of providing peer feedback in online learning have not been extensively studied. The goal of this study was therefore to explore the process of providing online

  5. A critical survey of agent-based wholesale electricity market models

    International Nuclear Information System (INIS)

    Weidlich, Anke; Veit, Daniel

    2008-01-01

    The complexity of electricity markets calls for rich and flexible modeling techniques that help to understand market dynamics and to derive advice for the design of appropriate regulatory frameworks. Agent-Based Computational Economics (ACE) is a fairly young research paradigm that offers methods for realistic electricity market modeling. A growing number of researchers have developed agent-based models for simulating electricity markets. The diversity of approaches makes it difficult to overview the field of ACE electricity research; this literature survey should guide the way through and describe the state-of-the-art of this research area. In a conclusive summary, shortcomings of existing approaches and open issues that should be addressed by ACE electricity researchers are critically discussed. (author)

  6. Tri-critical behavior of the Blume Capel model on a diamond lattice

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Jander P., E-mail: jander@ufsj.edu.br [Departamento de Ciências Naturais, Universidade Federal de São João del Rei, C.P. 110, CEP 36301-160 São João del Rei, MG (Brazil); Departamento de Matemática, Universidade Federal de São João del Rei, C.P. 110, CEP 36301-160 São João del Rei, MG (Brazil); Sá Barreto, F.C., E-mail: fcsabarreto@gmail.com [Departamento de Ciências Naturais, Universidade Federal de São João del Rei, C.P. 110, CEP 36301-160 São João del Rei, MG (Brazil); Emeritus Professor, Departamento de Física, Universidade Federal de Minas Gerais, C.P. 110, CEP 31270-901 Belo Horizonte, MG (Brazil); Rosa, D.S., E-mail: derick@ift.unesp.br [Instituto de Física Teórica, Universidade Estadual Paulista, C.P. 110, CEP 01140-070 São Paulo, SP (Brazil)

    2017-02-01

    The mean field approximation results are obtained in a five-site cluster on the diamond lattice from the Bogoliubov inequality. Spin correlation identities for the Blume-Capel model on diamond lattice are derived from a five-site cluster and used to obtain an effective field approximation. The free-energy, magnetization, critical frontiers and tricritical points are obtained from the mean field approximation and the effective field approximation and are compared to those obtained by other methods. From the mean-field approximation, we also studied the unstable and metastable states besides the stable states present in the model. - Highlights: • From the Bogoliubov inequality the mean field approximation is applied. • Correlation identities for the Blume-Capel model on a diamond lattice are obtained. • From the spin correlation identities the effective-field theory is applied. • Lines of phase transitions of first order and continuous are obtained. • Multicritical points are obtained according to this procedure.

  7. Improvements of Critical Heat Flux Models Based on the Viscous Potential Flow Theory

    International Nuclear Information System (INIS)

    Kim, Byoung Jae; Lee, Jong Hyuk; Kim, Kyung Doo

    2014-01-01

    The absence of fluid viscosities in most existing models may be attributed to the fact that inviscid flow analyses are performed for the model development. For example, the hydrodynamic theory and macrolayer dryout models rely on the Rayleigh-Taylor, Kelvin-Helmholtz, and capillary instabilities for inviscid fluids. However, as the viscosities of two fluids become closer, none of them cannot be neglected. Moreover, the gas viscosity effect cannot be neglected on the condition that the gas layer is thin. Nevertheless, the previous studies neglected the viscous effect. Recently, Kim et al. showed that for the model development of critical heat flux and minimum film boiling, the Rayleigh-Taylor instability should be analyzed with a thin layer of viscous gas instead of a thick layer of inviscid gas. The decrease of the most unstable wavelength was shown to improve the prediction accuracy of critical heat flux models for various fluids, particularly at elevated pressures. In addition, the most dangerous wavelength and the most rapid growth rate for viscous thin films are shown to be applicable to the minimum heat flux condition. Kim et al. touch only the most unstable wavelength for developing critical heat flux models. The critical heat flux is inversely proportional to the square root of the most unstable wavelength (Zuber, Guan et al). Here, we notice that the existing critical heat flux models make use of the Kelvin-Helmholtz instability of inviscid flows. The Kelvin-Helmholtz instability determines the maximum vapor escape velocity (Zuber) and the initial liquid macrolayer thickness (Haramura and Katto). Therefore, there is a room for improving the prediction accuracy by the help of the Kelvin-Helmholtz instability of viscous fluids. The Kelvin-Helmholtz instability arises when the different fluid layers are in relative motion. Usually, a uniform flow is considered in each fluid layer, allowing a velocity discontinuity at the interface. Therefore, in general, the

  8. A new approach to hazardous materials transportation risk analysis: decision modeling to identify critical variables.

    Science.gov (United States)

    Clark, Renee M; Besterfield-Sacre, Mary E

    2009-03-01

    We take a novel approach to analyzing hazardous materials transportation risk in this research. Previous studies analyzed this risk from an operations research (OR) or quantitative risk assessment (QRA) perspective by minimizing or calculating risk along a transport route. Further, even though the majority of incidents occur when containers are unloaded, the research has not focused on transportation-related activities, including container loading and unloading. In this work, we developed a decision model of a hazardous materials release during unloading using actual data and an exploratory data modeling approach. Previous studies have had a theoretical perspective in terms of identifying and advancing the key variables related to this risk, and there has not been a focus on probability and statistics-based approaches for doing this. Our decision model empirically identifies the critical variables using an exploratory methodology for a large, highly categorical database involving latent class analysis (LCA), loglinear modeling, and Bayesian networking. Our model identified the most influential variables and countermeasures for two consequences of a hazmat incident, dollar loss and release quantity, and is one of the first models to do this. The most influential variables were found to be related to the failure of the container. In addition to analyzing hazmat risk, our methodology can be used to develop data-driven models for strategic decision making in other domains involving risk.

  9. Off-critical statistical models: factorized scattering theories and bootstrap program

    International Nuclear Information System (INIS)

    Mussardo, G.

    1992-01-01

    We analyze those integrable statistical systems which originate from some relevant perturbations of the minimal models of conformal field theories. When only massive excitations are present, the systems can be efficiently characterized in terms of the relativistic scattering data. We review the general properties of the factorizable S-matrix in two dimensions with particular emphasis on the bootstrap principle. The classification program of the allowed spins of conserved currents and of the non-degenerate S-matrices is discussed and illustrated by means of some significant examples. The scattering theories of several massive perturbations of the minimal models are fully discussed. Among them are the Ising model, the tricritical Ising model, the Potts models, the series of the non-unitary minimal models M 2,2n+3 , the non-unitary model M 3,5 and the scaling limit of the polymer system. The ultraviolet limit of these massive integrable theories can be exploited by the thermodynamics Bethe ansatz, in particular the central charge of the original conformal theories can be recovered from the scattering data. We also consider the numerical method based on the so-called conformal space truncated approach which confirms the theoretical results and allows a direct measurement of the scattering data, i.e. the masses and the S-matrix of the particles in bootstrap interaction. The problem of computing the off-critical correlation functions is discussed in terms of the form-factor approach

  10. A critical comparison of systematic calibration protocols for activated sludge models: a SWOT analysis.

    Science.gov (United States)

    Sin, Gürkan; Van Hulle, Stijn W H; De Pauw, Dirk J W; van Griensven, Ann; Vanrolleghem, Peter A

    2005-07-01

    Modelling activated sludge systems has gained an increasing momentum after the introduction of activated sludge models (ASMs) in 1987. Application of dynamic models for full-scale systems requires essentially a calibration of the chosen ASM to the case under study. Numerous full-scale model applications have been performed so far which were mostly based on ad hoc approaches and expert knowledge. Further, each modelling study has followed a different calibration approach: e.g. different influent wastewater characterization methods, different kinetic parameter estimation methods, different selection of parameters to be calibrated, different priorities within the calibration steps, etc. In short, there was no standard approach in performing the calibration study, which makes it difficult, if not impossible, to (1) compare different calibrations of ASMs with each other and (2) perform internal quality checks for each calibration study. To address these concerns, systematic calibration protocols have recently been proposed to bring guidance to the modeling of activated sludge systems and in particular to the calibration of full-scale models. In this contribution four existing calibration approaches (BIOMATH, HSG, STOWA and WERF) will be critically discussed using a SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis. It will also be assessed in what way these approaches can be further developed in view of further improving the quality of ASM calibration. In this respect, the potential of automating some steps of the calibration procedure by use of mathematical algorithms is highlighted.

  11. Self-organized criticality in asymmetric exclusion model with noise for freeway traffic

    Science.gov (United States)

    Nagatani, Takashi

    1995-02-01

    The one-dimensional asymmetric simple-exclusion model with open boundaries for parallel update is extended to take into account temporary stopping of particles. The model presents the traffic flow on a highway with temporary deceleration of cars. Introducing temporary stopping into the asymmetric simple-exclusion model drives the system asymptotically into a steady state exhibiting a self-organized criticality. In the self-organized critical state, start-stop waves (or traffic jams) appear with various sizes (or lifetimes). The typical interval between consecutive jams scales as ≃ Lv with v = 0.51 ± 0.05 where L is the system size. It is shown that the cumulative jam-interval distribution Ns( L) satisfies the finite-size scaling form ( Ns( L) ≃ L- vf( s/ Lv). Also, the typical lifetime ≃ Lv‧ with v‧ = 0.52 ± 0.05. The cumulative distribution Nm( L) of lifetimes satisfies the finite-size scaling form Nm( L)≃ L-1g( m/ Lv‧).

  12. Leading CFT constraints on multi-critical models in d>2

    Energy Technology Data Exchange (ETDEWEB)

    Codello, Alessandro [CP-Origins, University of Southern Denmark,Campusvej 55, 5230 Odense M (Denmark); INFN - Sezione di Bologna,via Irnerio 46, 40126 Bologna (Italy); Safari, Mahmoud [INFN - Sezione di Bologna,via Irnerio 46, 40126 Bologna (Italy); Dipartimento di Fisica e Astronomia, Università di Bologna,via Irnerio 46, 40126 Bologna (Italy); Vacca, Gian Paolo [INFN - Sezione di Bologna,via Irnerio 46, 40126 Bologna (Italy); Zanusso, Omar [Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universität Jena,Max-Wien-Platz 1, 07743 Jena (Germany); INFN - Sezione di Bologna,via Irnerio 46, 40126 Bologna (Italy)

    2017-04-21

    We consider the family of renormalizable scalar QFTs with self-interacting potentials of highest monomial ϕ{sup m} below their upper critical dimensions d{sub c}=((2m)/(m−2)), and study them using a combination of CFT constraints, Schwinger-Dyson equation and the free theory behavior at the upper critical dimension. For even integers m≥4 these theories coincide with the Landau-Ginzburg description of multi-critical phenomena and interpolate with the unitary minimal models in d=2, while for odd m the theories are non-unitary and start at m=3 with the Lee-Yang universality class. For all the even potentials and for the Lee-Yang universality class, we show how the assumption of conformal invariance is enough to compute the scaling dimensions of the local operators ϕ{sup k} and of some families of structure constants in either the coupling’s or the ϵ-expansion. For all other odd potentials we express some scaling dimensions and structure constants in the coupling’s expansion.

  13. ANAEROBIC CAPACITY MAY NOT BE DETERMINED BY CRITICAL POWER MODEL IN ELITE TABLE TENNIS PLAYERS

    Directory of Open Access Journals (Sweden)

    Alessandro M. Zagatto

    2008-03-01

    Full Text Available The aim of the present study was to verify the applicability of anaerobic work capacity (AWC determined from the critical power model in elite table tennis players. Eight male international level table tennis players participated in the study. The tests undertaken were: 1 A critical frequency test used to determinate the anaerobic work capacity; 2 Wingate tests were performed using leg and arm ergometers. AWC corresponded to 99.5 ± 29.1 table tennis balls. AWC was not related to peak (r = -0.25, mean (r = -0.02, relative peak (r = -0.49 or relative mean power (r = 0.01, nor fatigue index (r = -0.52 (Wingate leg ergometer. Similar correlations for peak (r = -0.34, mean (r = -0.04, relative peak (r = -0.49, relative mean power (r = -0.14 and peak blood lactate concentration (r = -0.08 were determined in the Wingate arm ergometer test. Based on these results the AWC determined by a modified critical power test was not a good index for measurement of anaerobic capacity in table tennis players

  14. Anaerobic capacity may not be determined by critical power model in elite table tennis players.

    Science.gov (United States)

    Zagatto, Alessandro M; Papoti, Marcelo; Gobatto, Claudio A

    2008-01-01

    The aim of the present study was to verify the applicability of anaerobic work capacity (AWC) determined from the critical power model in elite table tennis players. Eight male international level table tennis players participated in the study. The tests undertaken were: 1) A critical frequency test used to determinate the anaerobic work capacity; 2) Wingate tests were performed using leg and arm ergometers. AWC corresponded to 99.5 ± 29.1 table tennis balls. AWC was not related to peak (r = -0.25), mean (r = -0.02), relative peak (r = -0.49) or relative mean power (r = 0.01), nor fatigue index (r = -0.52) (Wingate leg ergometer). Similar correlations for peak (r = -0.34), mean (r = -0.04), relative peak (r = -0.49), relative mean power (r = -0.14) and peak blood lactate concentration (r = -0.08) were determined in the Wingate arm ergometer test. Based on these results the AWC determined by a modified critical power test was not a good index for measurement of anaerobic capacity in table tennis players. Key pointsAnaerobic work capacity (AWC) was not good index of anaerobic capacity in table tennis.AWC determined using the table tennis ergometer showed low correlations with the Wingate test measures for cycle and arm ergometry.A sport-specific protocol is required for measuring anaerobic capacity in table tennis.

  15. Numerical modeling of continuous flow microwave heating: a critical comparison of COMSOL and ANSYS.

    Science.gov (United States)

    Salvi, D; Boldor, Dorin; Ortego, J; Aita, G M; Sabliov, C M

    2010-01-01

    Numerical models were developed to simulate temperature profiles in Newtonian fluids during continuous flow microwave heating by one way coupling electromagnetism, fluid flow, and heat transport in ANSYS 8.0 and COMSOL Multiphysics v3.4. Comparison of the results from the COMSOL model with the results from a pre-developed and validated ANSYS model ensured accuracy of the COMSOL model. Prediction of power Loss by both models was in close agreement (5-13% variation) and the predicted temperature profiles were similar. COMSOL provided a flexible model setup whereas ANSYS required coupling incompatible elements to transfer load between electromagnetic, fluid flow, and heat transport modules. Overall, both software packages provided the ability to solve multiphysics phenomena accurately.

  16. Nonuniversal critical behaviour in a model for charge density wave dynamics

    International Nuclear Information System (INIS)

    Ritala, R.K.; Hertz, J.A.

    1986-02-01

    We have studied short range fluctuations around the infinite-range model of charge density wave (CDW) dynamics. We find that the inhomogeneity of the local field, which is neglected in the infinite-range approximation has a dramatic effect on the transition. In the Bethe approximation the critical behaviour is nonuniversal. In particular, the current exponent is ζ = 3/2 log(z-1)/[log(z)]+log(1+f/J)], where z is the number of neighbors, f the pinning strength, and J the elastic coupling. (orig.)

  17. 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.

  18. Modeling, Evaluation and Detection of Jamming Attacks in Time-Critical Wireless Applications

    Science.gov (United States)

    2014-08-01

    gambler’s ruin problem [24], has been well investi- gated by mathematicians. It has been shown that martingale theory [24], a branch of modern probabilistic...solve it by using martingale theory. We first construct a game for a gambler shown in Fig. 3. The gambler starts with X0 = d0 dollars. In the n-th play...that this value is essential to our martingale construction. LU ET AL.: MODELING, EVALUATION AND DETECTION OF JAMMING ATTACKS IN TIME-CRITICAL WIRELESS

  19. Finite-dimensional effects and critical indices of one-dimensional quantum models

    International Nuclear Information System (INIS)

    Bogolyubov, N.M.; Izergin, A.G.; Reshetikhin, N.Yu.

    1986-01-01

    Critical indices, depending on continuous parameters in Bose-gas quantum models and Heisenberg 1/2 spin antiferromagnetic in two-dimensional space-time at zero temperature, have been calculated by means of finite-dimensional effects. In this case the long-wave asymptotics of the correlation functions is of a power character. Derivation of man asymptotics terms is reduced to the determination of a central charge in the appropriate Virassoro algebra representation and the anomalous dimension-operator spectrum in this representation. The finite-dimensional effects allow to find these values

  20. Evaluating critical uncertainty thresholds in a spatial model of forest pest invasion risk

    Science.gov (United States)

    Frank H. Koch; Denys Yemshanov; Daniel W. McKenney; William D. Smith

    2009-01-01

    Pest risk maps can provide useful decision support in invasive species management, but most do not adequately consider the uncertainty associated with predicted risk values. This study explores how increased uncertainty in a risk model’s numeric assumptions might affect the resultant risk map. We used a spatial stochastic model, integrating components for...

  1. A Deep Search for Satellites in the Pluto System: Providing Critical, Safety-of-Flight Support to NASA's New Horizons Mission

    Science.gov (United States)

    Weaver, Harold

    2010-09-01

    We propose a simple, 9-orbit {3 orbits at each of 3 epochs} DD programwith two objectives: {1} as a safety-of-flight issue, perform a deepsearch {V=25-26} for satellites in the 0.9 arcsec radius region betweenPluto and Charon where NASA's New Horizons mission will fly, and {2}confirm or reject the candidate P5 and P6 satellites seen in recent HSTimaging, while performing an even deeper search {V=27} for satellites inthe region between Charon and Hydra so observations of them can beplanned before the New Horizons mission planning is frozen prior to theon-spacecraft rehearsal. Hubble is uniquely qualified to achieve thesetime-critical objectives, which we hope to achieve before the Pluto systementers the Hubble solar exclusion zone in early November.

  2. Providing Agility in C2 Environments Through Networked Information Processing: A Model of Expertise

    Science.gov (United States)

    2014-06-01

    individual being able to correctly identify the solution in various circumstances. A three-parameter logistic ( 3PL ) model is used, where the...difficulty. Based on this 3PL model, we choose to fit the parameters of the following expression for the probability of a correct response given...problem difficulty can predict accuracy of responses to specific questions • Three-parameter logistic ( 3PL ) model b – difficulty a

  3. The Hazard Analysis and Critical Control Points (HACCP) generic model for the production of Thai fermented pork sausage (Nham).

    Science.gov (United States)

    Paukatong, K V; Kunawasen, S

    2001-01-01

    Nham is a traditional Thai fermented pork sausage. The major ingredients of Nham are ground pork meat and shredded pork rind. Nham has been reported to be contaminated with Salmonella spp., Staphylococcus aureus, and Listeria monocytogenes. Therefore, it is a potential cause of foodborne diseases for consumers. A Hazard Analysis and Critical Control Points (HACCP) generic model has been developed for the Nham process. Nham processing plants were observed and a generic flow diagram of Nham processes was constructed. Hazard analysis was then conducted. Other than microbial hazards, the pathogens previously found in Nham, sodium nitrite and metal were identified as chemical and physical hazards in this product, respectively. Four steps in the Nham process have been identified as critical control points. These steps are the weighing of the nitrite compound, stuffing, fermentation, and labeling. The chemical hazard of nitrite must be controlled during the weighing step. The critical limit of nitrite levels in the Nham mixture has been set at 100-200 ppm. This level is high enough to control Clostridium botulinum but does not cause chemical hazards to the consumer. The physical hazard from metal clips could be prevented by visual inspection of every Nham product during stuffing. The microbiological hazard in Nham could be reduced in the fermentation process. The critical limit of the pH of Nham was set at lower than 4.6. Since this product is not cooked during processing, finally, educating the consumer, by providing information on the label such as "safe if cooked before consumption", could be an alternative way to prevent the microbiological hazards of this product.

  4. Economic model of a cloud provider operating in a federated cloud

    OpenAIRE

    Goiri Presa, Íñigo; Guitart Fernández, Jordi; Torres Viñals, Jordi

    2012-01-01

    Resource provisioning in Cloud providers is a challenge because of the high variability of load over time. On the one hand, the providers can serve most of the requests owning only a restricted amount of resources, but this forces to reject customers during peak hours. On the other hand, valley hours incur in under-utilization of the resources, which forces the providers to increase their prices to be profitable. Federation overcomes these limitations and allows pro...

  5. An Integral Model to Provide Reactive and Proactive Services in an Academic CSIRT Based on Business Intelligence

    Directory of Open Access Journals (Sweden)

    Walter Fuertes

    2017-11-01

    Full Text Available Cyber-attacks have increased in severity and complexity. That requires, that the CERT/CSIRT research and develops new security tools. Therefore, our study focuses on the design of an integral model based on Business Intelligence (BI, which provides reactive and proactive services in a CSIRT, in order to alert and reduce any suspicious or malicious activity on information systems and data networks. To achieve this purpose, a solution has been assembled, that generates information stores, being compiled from a continuous network transmission of several internal and external sources of an organization. However, it contemplates a data warehouse, which is focused like a correlator of logs, being formed by the information of feeds with diverse formats. Furthermore, it analyzed attack detection and port scanning, obtained from sensors such as Snort and Passive Vulnerability Scanner, which are stored in a database, where the logs have been generated by the systems. With such inputs, we designed and implemented BI systems using the phases of the Ralph Kimball methodology, ETL and OLAP processes. In addition, a software application has been implemented using the SCRUM methodology, which allowed to link the obtained logs to the BI system for visualization in dynamic dashboards, with the purpose of generating early alerts and constructing complex queries using the user interface through objects structures. The results demonstrate, that this solution has generated early warnings based on the level of criticality and level of sensitivity of malware and vulnerabilities as well as monitoring efficiency, increasing the level of security of member institutions.

  6. Quantum critical scaling for field-induced quantum phase transition in a periodic Anderson-like model polymer chain

    Energy Technology Data Exchange (ETDEWEB)

    Ding, L.J., E-mail: dinglinjie82@126.com; Zhong, Y.

    2017-07-15

    Highlights: • The quantum critical scaling is investigated by Green’s function theory. • The obtained power-law critical exponents (β, δ and α) obey the critical scaling relation α + β(1 + δ) = 2. • The scaling hypothesis equations are proposed to verify the scaling analysis. - Abstract: The quantum phase transition and thermodynamics of a periodic Anderson-like polymer chain in a magnetic field are investigated by Green’s function theory. The T-h phase diagram is explored, wherein a crossover temperature T{sup ∗} denoting the gapless phase crossover into quantum critical regimes, smoothly connects near the critical fields to the universal linear line T{sup ∗} ∼ (h − h{sub c,s}), and ends at h{sub c,s}, providing a new route to capture quantum critical point (QCP). The quantum critical scaling around QCPs is demonstrated by analyzing magnetization, specific heat and Grüneisen parameter Γ{sub h}, which provide direct access to distill the power-law critical exponents (β, δ and α) obeying the critical scaling relation α + β(1 + δ) = 2, analogous to the quantum spin system. Furthermore, scaling hypothesis equations are proposed to check the scaling analysis, for which all the data collapse onto a single curve or two independent branches for the plot against an appropriate scaling variable, indicating the self-consistency and reliability of the obtained critical exponents.

  7. Systematic Identification of Machine-Learning Models Aimed to Classify Critical Residues for Protein Function from Protein Structure.

    Science.gov (United States)

    Corral-Corral, Ricardo; Beltrán, Jesús A; Brizuela, Carlos A; Del Rio, Gabriel

    2017-10-09

    Protein structure and protein function should be related, yet the nature of this relationship remains unsolved. Mapping the critical residues for protein function with protein structure features represents an opportunity to explore this relationship, yet two important limitations have precluded a proper analysis of the structure-function relationship of proteins: (i) the lack of a formal definition of what critical residues are and (ii) the lack of a systematic evaluation of methods and protein structure features. To address this problem, here we introduce an index to quantify the protein-function criticality of a residue based on experimental data and a strategy aimed to optimize both, descriptors of protein structure (physicochemical and centrality descriptors) and machine learning algorithms, to minimize the error in the classification of critical residues. We observed that both physicochemical and centrality descriptors of residues effectively relate protein structure and protein function, and that physicochemical descriptors better describe critical residues. We also show that critical residues are better classified when residue criticality is considered as a binary attribute (i.e., residues are considered critical or not critical). Using this binary annotation for critical residues 8 models rendered accurate and non-overlapping classification of critical residues, confirming the multi-factorial character of the structure-function relationship of proteins.

  8. A Distance Education Model for Training Substance Abuse Treatment Providers in Cognitive-Behavioral Therapy

    Science.gov (United States)

    Watson, Donnie W.; Rawson, Richard R.; Rataemane, Solomon; Shafer, Michael S.; Obert, Jeanne; Bisesi, Lorrie; Tanamly, Susie

    2003-01-01

    This paper presents a rationale for the use of a distance education approach in the clinical training of community substance abuse treatment providers. Developing and testing new approaches to the clinical training and supervision of providers is important in the substance abuse treatment field where new information is always available. A…

  9. Efficient Actor-Critic Algorithm with Hierarchical Model Learning and Planning

    Science.gov (United States)

    Fu, QiMing

    2016-01-01

    To improve the convergence rate and the sample efficiency, two efficient learning methods AC-HMLP and RAC-HMLP (AC-HMLP with ℓ 2-regularization) are proposed by combining actor-critic algorithm with hierarchical model learning and planning. The hierarchical models consisting of the local and the global models, which are learned at the same time during learning of the value function and the policy, are approximated by local linear regression (LLR) and linear function approximation (LFA), respectively. Both the local model and the global model are applied to generate samples for planning; the former is used only if the state-prediction error does not surpass the threshold at each time step, while the latter is utilized at the end of each episode. The purpose of taking both models is to improve the sample efficiency and accelerate the convergence rate of the whole algorithm through fully utilizing the local and global information. Experimentally, AC-HMLP and RAC-HMLP are compared with three representative algorithms on two Reinforcement Learning (RL) benchmark problems. The results demonstrate that they perform best in terms of convergence rate and sample efficiency. PMID:27795704

  10. A New Approach of Modeling an Ultra-Super-Critical Power Plant for Performance Improvement

    Directory of Open Access Journals (Sweden)

    Guolian Hou

    2016-04-01

    Full Text Available A suitable model of coordinated control system (CCS with high accuracy and simple structure is essential for the design of advanced controllers which can improve the efficiency of the ultra-super-critical (USC power plant. Therefore, with the demand of plant performance improvement, an improved T-S fuzzy model identification approach is proposed in this paper. Firstly, the improved entropy cluster algorithm is applied to identify the premise parameters which can automatically determine the cluster numbers and initial cluster centers by introducing the concept of a decision-making constant and threshold. Then, the learning algorithm is used to modify the initial cluster center and a new structure of concluding part is discussed, the incremental data around the cluster center is used to identify the local linear model through a weighted recursive least-square algorithm. Finally, the proposed approach is employed to model the CCS of a 1000 MW USC one-through boiler power plant by using on-site measured data. Simulation results show that the T-S fuzzy model built in this paper is accurate enough to reflect the dynamic performance of CCS and can be treated as a foundation model for the overall optimizing control of the USC power plant.

  11. Efficient Actor-Critic Algorithm with Hierarchical Model Learning and Planning

    Directory of Open Access Journals (Sweden)

    Shan Zhong

    2016-01-01

    Full Text Available To improve the convergence rate and the sample efficiency, two efficient learning methods AC-HMLP and RAC-HMLP (AC-HMLP with l2-regularization are proposed by combining actor-critic algorithm with hierarchical model learning and planning. The hierarchical models consisting of the local and the global models, which are learned at the same time during learning of the value function and the policy, are approximated by local linear regression (LLR and linear function approximation (LFA, respectively. Both the local model and the global model are applied to generate samples for planning; the former is used only if the state-prediction error does not surpass the threshold at each time step, while the latter is utilized at the end of each episode. The purpose of taking both models is to improve the sample efficiency and accelerate the convergence rate of the whole algorithm through fully utilizing the local and global information. Experimentally, AC-HMLP and RAC-HMLP are compared with three representative algorithms on two Reinforcement Learning (RL benchmark problems. The results demonstrate that they perform best in terms of convergence rate and sample efficiency.

  12. THM modelling of buffer, backfill and other system components. Critical processes and scenarios

    International Nuclear Information System (INIS)

    Aakesson, Mattias; Kristensson, Ola; Boergesson, Lennart; Dueck, Ann; Hernelind, Jan

    2010-03-01

    A number of critical thermo-hydro-mechanical processes and scenarios for the buffer, tunnel backfill and other filling components in the repository have been identified. These processes and scenarios representing different aspects of the repository evolution have been pinpointed and modelled. In total, 22 cases have been modelled. Most cases have been analysed with finite element (FE) calculations, using primarily the two codes Abaqus and Code B right. For some cases analytical methods have been used either to supplement the FE calculations or due to that the scenario has a character that makes it unsuitable or very difficult to use the FE method. Material models and element models and choice of parameters as well as presumptions have been stated for all modelling cases. In addition, the results have been analysed and conclusions drawn for each case. The uncertainties have also been analysed. Besides the information given for all cases studied, the codes and material models have been described in a separate so called data report

  13. THM modelling of buffer, backfill and other system components. Critical processes and scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Aakesson, Mattias; Kristensson, Ola; Boergesson, Lennart; Dueck, Ann (Clay Technology AB, Lund (Sweden)); Hernelind, Jan (5T-Engineering AB, Vaesteraas (Sweden))

    2010-03-15

    A number of critical thermo-hydro-mechanical processes and scenarios for the buffer, tunnel backfill and other filling components in the repository have been identified. These processes and scenarios representing different aspects of the repository evolution have been pinpointed and modelled. In total, 22 cases have been modelled. Most cases have been analysed with finite element (FE) calculations, using primarily the two codes Abaqus and Code-Bright. For some cases analytical methods have been used either to supplement the FE calculations or due to that the scenario has a character that makes it unsuitable or very difficult to use the FE method. Material models and element models and choice of parameters as well as presumptions have been stated for all modelling cases. In addition, the results have been analysed and conclusions drawn for each case. The uncertainties have also been analysed. Besides the information given for all cases studied, the codes and material models have been described in a separate so called data report

  14. Re-Imagining Initial Multiracial Teacher Education (IMTE) Model through the ODL Philosophy: A Critical Qualitative Meta-Synthesis Study

    Science.gov (United States)

    Nyoni, J.

    2012-01-01

    This article reports on a critical meta-analysis of empirical studies done by human sciences researchers on the initial multicultural teacher education (IMTE) models in multicultural post-colonial transitional societies with reference to sub-Saharan African states in general and South Africa in particular. Using a critical post-positivist…

  15. ANALYZE CRITICAL THINKING SKILLS AND SCIENTIFIC ATTITUDE IN PHYSICS LEARNING USED INQUIRY TRAINING AND DIRECT INSTRUCTION LEARNING MODEL

    Directory of Open Access Journals (Sweden)

    Dede Parsaoran Damanik

    2013-06-01

    Full Text Available This study was aimed to determine the differences: (1 the difference of critical thinking skills of students' that using Inquiry Training and Direct Instruction. (2 The difference of critical thinking skills among students who at high scientific attitude and students who at low scientific attitude. (3 To see if there is interaction between inquiry learning model of the scientific attitude students' to increase the ability to critical thinking. This is a quasi experimental research. Which students of private junior high school Two Raya Kahean District Simalungun. Population choose random sample of each class. Instrument used consisted of: (1 test the scientific attitude of students through a questionnaire with 25 statements questionnaire number (2 test the critical thinking skills in the form of descriptions by 9 questions. The data were analyzed according to ANAVA. It showed that: (1 There are differences in students' critical thinking of skills achievement Inquiry Training model and Direct Instruction model, (2 there was a difference of students' critical thinking in scientific attitude at high is better than who thought there is a difference of students' critical thinking in scientific attitude at low. (3 There was no interaction between Inquiry Training model and Direct Instruction with the scientific attitude students' to increase student’s critical thinking of skills.

  16. An integrated model to assess critical rain fall thresholds for the critical run-out distances of debris flows

    NARCIS (Netherlands)

    van Asch, Th.W.J.|info:eu-repo/dai/nl/304839558; Tang, C.; Alkema, D.; Zhu, J.; Zhou, W.

    2013-01-01

    A dramatic increase in debris flows occurred in the years after the 2008 Wenchuan earthquake in SW China due to the deposition of loose co-seismic landslide material. This paper proposes a preliminary integrated model, which describes the relationship between rain input and debris flow run-out in

  17. A Dynamical Model of Pitch Memory Provides an Improved Basis for Implied Harmony Estimation

    Science.gov (United States)

    Kim, Ji Chul

    2017-01-01

    Tonal melody can imply vertical harmony through a sequence of tones. Current methods for automatic chord estimation commonly use chroma-based features extracted from audio signals. However, the implied harmony of unaccompanied melodies can be difficult to estimate on the basis of chroma content in the presence of frequent nonchord tones. Here we present a novel approach to automatic chord estimation based on the human perception of pitch sequences. We use cohesion and inhibition between pitches in auditory short-term memory to differentiate chord tones and nonchord tones in tonal melodies. We model short-term pitch memory as a gradient frequency neural network, which is a biologically realistic model of auditory neural processing. The model is a dynamical system consisting of a network of tonotopically tuned nonlinear oscillators driven by audio signals. The oscillators interact with each other through nonlinear resonance and lateral inhibition, and the pattern of oscillatory traces emerging from the interactions is taken as a measure of pitch salience. We test the model with a collection of unaccompanied tonal melodies to evaluate it as a feature extractor for chord estimation. We show that chord tones are selectively enhanced in the response of the model, thereby increasing the accuracy of implied harmony estimation. We also find that, like other existing features for chord estimation, the performance of the model can be improved by using segmented input signals. We discuss possible ways to expand the present model into a full chord estimation system within the dynamical systems framework. PMID:28522983

  18. Bilateral sequential cochlear implantation in the congenitally deaf child: evidence to support the concept of a 'critical age' after which the second ear is less likely to provide an adequate level of speech perception on its own.

    Science.gov (United States)

    Graham, John; Vickers, Debi; Eyles, Julie; Brinton, Julie; Al Malky, Ghada; Aleksy, Wanda; Martin, Jane; Henderson, Lise; Mawman, Deborah; Robinson, Philip; Midgley, Elizabeth; Hanvey, Kate; Twomey, Tracey; Johnson, Susan; Vanat, Zebunnisa; Broxholme, Cath; McAnallen, Cecilia; Allen, Agnes; Bray, Monica

    2009-09-01

    This study attempts to answer the question of whether there is a 'critical age' after which a second contralateral cochlear implant is less likely to provide enough speech perception to be of practical use. The study was not designed to predict factors that determine successful binaural implant use, but to see if there was evidence to help determine the latest age at which the second ear can usefully be implanted, should the first side fail and become unusable.Outcome data, in the form of speech perception test results, were collected from 11 cochlear implant programmes in the UK and one centre in Australia. Forty-seven congenitally bilaterally deaf subjects who received bilateral sequential implants were recruited to the study. The study also included four subjects with congenital unilateral profound deafness who had lost all hearing in their only hearing ear and received a cochlear implant in their unilaterally congenitally deaf ear. Of those 34 subjects for whom complete sets of data were available, the majority (72%) of those receiving their second (or unilateral) implant up to the age of 13 years scored 60 per cent or above in the Bamford Kowal Bench (BKB) sentence test, or equivalent. In contrast, of those nine receiving their second or unilateral implant at the age of 15 or above, none achieved adequate levels of speech perception on formal testing: two scored 29 per cent and 30 per cent, respectively, and the rest seven per cent or less.A discriminant function analysis performed on the data suggests that it is unlikely that a second contralateral implant received after the age of 16 to 18 years will, on its own, provide adequate levels of speech perception. As more children receive sequential bilateral cochlear implants and the pool of data enlarges the situation is likely to become clearer.The results provide support for the concept of a 'critical age' for implanting the second ear in successful congenitally deaf unilateral cochlear implant users. This

  19. Predicting the local impacts of energy development: a critical guide to forecasting methods and models

    Energy Technology Data Exchange (ETDEWEB)

    Sanderson, D.; O' Hare, M.

    1977-05-01

    Models forecasting second-order impacts from energy development vary in their methodology, output, assumptions, and quality. As a rough dichotomy, they either simulate community development over time or combine various submodels providing community snapshots at selected points in time. Using one or more methods - input/output models, gravity models, econometric models, cohort-survival models, or coefficient models - they estimate energy-development-stimulated employment, population, public and private service needs, and government revenues and expenditures at some future time (ranging from annual to average year predictions) and for different governmental jurisdictions (municipal, county, state, etc.). Underlying assumptions often conflict, reflecting their different sources - historical data, comparative data, surveys, and judgments about future conditions. Model quality, measured by special features, tests, exportability and usefulness to policy-makers, reveals careful and thorough work in some cases and hurried operations with insufficient in-depth analysis in others.

  20. A significant advantage for trapped field magnet applications—A failure of the critical state model

    Science.gov (United States)

    Weinstein, Roy; Parks, Drew; Sawh, Ravi-Persad; Carpenter, Keith; Davey, Kent

    2015-10-01

    Ongoing research has increased achievable field in trapped field magnets (TFMs) to multi-Tesla levels. This has greatly increased the attractiveness of TFMs for applications. However, it also increases the already very difficult problem of in situ activation and reactivation of the TFMs. The pulsed zero-field-cool (ZFC) method of activation is used in most applications because it can be accomplished with much lower power and more modest equipment than field-cool activation. The critical state model (CSM) has been a reliable theoretical tool for experimental analysis and engineering design of TFMs and their applications for over a half-century. The activating field, BA, required to fully magnetize a TFM to its maximum trappable field, BT,max, using pulsed-ZFC is predicted by CSM to be R ≡ BA/BT,max ≥ 2.0. We report here experiments on R as a function of Jc, which find a monotonic decrease of R to 1.0 as Jc increases. The reduction to R = 1.0 reduces the power needed to magnetize TFMs by about an order of magnitude. This is a critical advantage for TFM applications. The results also indicate the limits of applicability of CSM, and shed light on the physics omitted from the model. The experimental results rule out heating effects and pinning center geometry as causes of the decrease in R. A possible physical cause is proposed.

  1. A theoretical critical heat flux model for low-pressure, low-mass-flux, and low-steam quality conditions

    International Nuclear Information System (INIS)

    Weihsiao Ho; Kuanchywan Tu; Baushei Pei; Chinjang Chang

    1993-01-01

    The critical heat flux (CHF) is the maximum heat flux just before a boiling crisis; its importance as a measurement of nuclear reactor power capability design as well as in the safety of reactors has been recognized. With emphasis on CHF behavior under subcooled and low-quality (i.e., 2 ·s), an improved model that uses the sublayer dry out theory has been developed. Based on experimental observations of CHF, the model assumes that CHF under such conditions is of the departure from nucleate boiling type. Based on the postulation that CHF is triggered by Helmholtz instability in the sublayer steam-liquid system, the model was developed by a simple energy balance of liquid sublayer evaporation as the vapor blanket tends to disturb the balance between the buoyancy force and the drag force exerted upon it. The model is compared with the well-known Biasi et al. correlation as well as the Atomic Energy of Canada Limited lookup table against 102 uniformly heated round tube CHF data and 34 nonuniformly heated round tube CHF data. The comparison shows that the model provides better accuracy and a reasonable agreement between the predicted values and experimental CHF data

  2. Modelling the hare and the tortoise: predicting the range of in-vehicle task times using critical path analysis.

    Science.gov (United States)

    Harvey, Catherine; Stanton, Neville A

    2013-01-01

    Analytic models can enable predictions about important aspects of the usability of in-vehicle information systems (IVIS) to be made at an early stage of the product development process. Task times provide a quantitative measure of user performance and are therefore important in the evaluation of IVIS usability. In this study, critical path analysis (CPA) was used to model IVIS task times in a stationary vehicle, and the technique was extended to produce predictions for slowperson and fastperson performance, as well as average user (middleperson) performance. The CPA-predicted task times were compared to task times recorded in an empirical simulator study of IVIS interaction, and the predicted times were, on average, within acceptable precision limits. This work forms the foundation for extension of the CPA model to predict IVIS task times in a moving vehicle, to reflect the demands of the dual-task driving scenario. The CPA method was extended for the prediction of slowperson and fastperson IVIS task times. Comparison of the model predictions with empirical data demonstrated acceptable precision. The CPA model can be used in early IVIS evaluation; however, there is a need to extend it to represent the dual-task driving scenario.

  3. 75 FR 2562 - Publication of Model Notices for Health Care Continuation Coverage Provided Pursuant to the...

    Science.gov (United States)

    2010-01-15

    ... DEPARTMENT OF LABOR Employee Benefits Security Administration Publication of Model Notices for... AGENCY: Employee Benefits Security Administration, Department of Labor. ACTION: Notice of the..., contact the Department's Employee Benefits Security Administration's Benefits Advisors at 1-866-444-3272...

  4. Ensemble modeling of the Baltic Sea ecosystem to provide scenarios for management.

    Science.gov (United States)

    Meier, H E Markus; Andersson, Helén C; Arheimer, Berit; Donnelly, Chantal; Eilola, Kari; Gustafsson, Bo G; Kotwicki, Lech; Neset, Tina-Simone; Niiranen, Susa; Piwowarczyk, Joanna; Savchuk, Oleg P; Schenk, Frederik; Węsławski, Jan Marcin; Zorita, Eduardo

    2014-02-01

    We present a multi-model ensemble study for the Baltic Sea, and investigate the combined impact of changing climate, external nutrient supply, and fisheries on the marine ecosystem. The applied regional climate system model contains state-of-the-art component models for the atmosphere, sea ice, ocean, land surface, terrestrial and marine biogeochemistry, and marine food-web. Time-dependent scenario simulations for the period 1960-2100 are performed and uncertainties of future projections are estimated. In addition, reconstructions since 1850 are carried out to evaluate the models sensitivity to external stressors on long time scales. Information from scenario simulations are used to support decision-makers and stakeholders and to raise awareness of climate change, environmental problems, and possible abatement strategies among the general public using geovisualization. It is concluded that the study results are relevant for the Baltic Sea Action Plan of the Helsinki Commission.

  5. Universal Scaling and Critical Exponents of the Anisotropic Quantum Rabi Model

    Science.gov (United States)

    Liu, Maoxin; Chesi, Stefano; Ying, Zu-Jian; Chen, Xiaosong; Luo, Hong-Gang; Lin, Hai-Qing

    2017-12-01

    We investigate the quantum phase transition of the anisotropic quantum Rabi model, in which the rotating and counterrotating terms are allowed to have different coupling strengths. The model interpolates between two known limits with distinct universal properties. Through a combination of analytic and numerical approaches, we extract the phase diagram, scaling functions, and critical exponents, which determine the universality class at finite anisotropy (identical to the isotropic limit). We also reveal other interesting features, including a superradiance-induced freezing of the effective mass and discontinuous scaling functions in the Jaynes-Cummings limit. Our findings are extended to the few-body quantum phase transitions with N >1 spins, where we expose the same effective parameters, scaling properties, and phase diagram. Thus, a stronger form of universality is established, valid from N =1 up to the thermodynamic limit.

  6. Assessing the Vulnerability of Large Critical Infrastructure Using Fully-Coupled Blast Effects Modeling

    Energy Technology Data Exchange (ETDEWEB)

    McMichael, L D; Noble, C R; Margraf, J D; Glascoe, L G

    2009-03-26

    Structural failures, such as the MacArthur Maze I-880 overpass in Oakland, California and the I-35 bridge in Minneapolis, Minnesota, are recent examples of our national infrastructure's fragility and serve as an important reminder of such infrastructure in our everyday lives. These two failures, as well as the World Trade Center's collapse and the levee failures in New Orleans, highlight the national importance of protecting our infrastructure as much as possible against acts of terrorism and natural hazards. This paper describes a process for evaluating the vulnerability of critical infrastructure to large blast loads using a fully-coupled finite element approach. A description of the finite element software and modeling technique is discussed along with the experimental validation of the numerical tools. We discuss how such an approach can be used for specific problems such as modeling the progressive collapse of a building.

  7. Bohr model description of the critical point for the first order shape phase transition

    Science.gov (United States)

    Budaca, R.; Buganu, P.; Budaca, A. I.

    2018-01-01

    The critical point of the shape phase transition between spherical and axially deformed nuclei is described by a collective Bohr Hamiltonian with a sextic potential having simultaneous spherical and deformed minima of the same depth. The particular choice of the potential as well as the scaled and decoupled nature of the total Hamiltonian leads to a model with a single free parameter connected to the height of the barrier which separates the two minima. The solutions are found through the diagonalization in a basis of Bessel functions. The basis is optimized for each value of the free parameter by means of a boundary deformation which assures the convergence of the solutions for a fixed basis dimension. Analyzing the spectral properties of the model, as a function of the barrier height, revealed instances with shape coexisting features which are considered for detailed numerical applications.

  8. Bohr model description of the critical point for the first order shape phase transition

    Directory of Open Access Journals (Sweden)

    R. Budaca

    2018-01-01

    Full Text Available The critical point of the shape phase transition between spherical and axially deformed nuclei is described by a collective Bohr Hamiltonian with a sextic potential having simultaneous spherical and deformed minima of the same depth. The particular choice of the potential as well as the scaled and decoupled nature of the total Hamiltonian leads to a model with a single free parameter connected to the height of the barrier which separates the two minima. The solutions are found through the diagonalization in a basis of Bessel functions. The basis is optimized for each value of the free parameter by means of a boundary deformation which assures the convergence of the solutions for a fixed basis dimension. Analyzing the spectral properties of the model, as a function of the barrier height, revealed instances with shape coexisting features which are considered for detailed numerical applications.

  9. Modelling critical degrees of saturation of porous building materials subjected to freezing

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1996-01-01

    of SCR based on fracture mechanics and phase geometry of two-phase materials has been developed.The degradation is modelled as being caused by different eigenstrains of the pore phase and the solid phase when freezing, leading to stress concentrations and crack propagation. Simplifications are made......Frost resistance of porous materials can be characterized by the critical degree of saturation, SCR, and the actual degree of saturation, SACT. An experimental determination of SCR is very laborious and therefore only seldom used when testing frost resistance. A theoretical model for prediction...... to describe the development of stresses and the pore structure, because a mathematical description of the physical theories explaining the process of freezing of water in porous materials is lacking.Calculations are based on porosity, modulus of elasticity and tensile strength, and parameters characterizing...

  10. Quantifying and modelling the carbon sequestration capacity of seagrass meadows--a critical assessment.

    Science.gov (United States)

    Macreadie, P I; Baird, M E; Trevathan-Tackett, S M; Larkum, A W D; Ralph, P J

    2014-06-30

    Seagrasses are among the planet's most effective natural ecosystems for sequestering (capturing and storing) carbon (C); but if degraded, they could leak stored C into the atmosphere and accelerate global warming. Quantifying and modelling the C sequestration capacity is therefore critical for successfully managing seagrass ecosystems to maintain their substantial abatement potential. At present, there is no mechanism to support carbon financing linked to seagrass. For seagrasses to be recognised by the IPCC and the voluntary C market, standard stock assessment methodologies and inventories of seagrass C stocks are required. Developing accurate C budgets for seagrass meadows is indeed complex; we discuss these complexities, and, in addition, we review techniques and methodologies that will aid development of C budgets. We also consider a simple process-based data assimilation model for predicting how seagrasses will respond to future change, accompanied by a practical list of research priorities. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. A description of model 3B of the multipurpose ventricular actuating system. [providing controlled driving pressures

    Science.gov (United States)

    Webb, J. A., Jr.

    1974-01-01

    The multipurpose ventricular actuating system is a pneumatic signal generating device that provides controlled driving pressures for actuating pulsatile blood pumps. Overall system capabilities, the timing circuitry, and calibration instruction are included.

  12. Oxygen distribution in tumors: A qualitative analysis and modeling study providing a novel Monte Carlo approach

    International Nuclear Information System (INIS)

    Lagerlöf, Jakob H.; Kindblom, Jon; Bernhardt, Peter

    2014-01-01

    Purpose: To construct a Monte Carlo (MC)-based simulation model for analyzing the dependence of tumor oxygen distribution on different variables related to tumor vasculature [blood velocity, vessel-to-vessel proximity (vessel proximity), and inflowing oxygen partial pressure (pO 2 )]. Methods: A voxel-based tissue model containing parallel capillaries with square cross-sections (sides of 10 μm) was constructed. Green's function was used for diffusion calculations and Michaelis-Menten's kinetics to manage oxygen consumption. The model was tuned to approximately reproduce the oxygenational status of a renal carcinoma; the depth oxygenation curves (DOC) were fitted with an analytical expression to facilitate rapid MC simulations of tumor oxygen distribution. DOCs were simulated with three variables at three settings each (blood velocity, vessel proximity, and inflowing pO 2 ), which resulted in 27 combinations of conditions. To create a model that simulated variable oxygen distributions, the oxygen tension at a specific point was randomly sampled with trilinear interpolation in the dataset from the first simulation. Six correlations between blood velocity, vessel proximity, and inflowing pO 2 were hypothesized. Variable models with correlated parameters were compared to each other and to a nonvariable, DOC-based model to evaluate the differences in simulated oxygen distributions and tumor radiosensitivities for different tumor sizes. Results: For tumors with radii ranging from 5 to 30 mm, the nonvariable DOC model tended to generate normal or log-normal oxygen distributions, with a cut-off at zero. The pO 2 distributions simulated with the six-variable DOC models were quite different from the distributions generated with the nonvariable DOC model; in the former case the variable models simulated oxygen distributions that were more similar to in vivo results found in the literature. For larger tumors, the oxygen distributions became truncated in the lower

  13. Common and Critical Components Among Community Health Assessment and Community Health Improvement Planning Models.

    Science.gov (United States)

    Pennel, Cara L; Burdine, James N; Prochaska, John D; McLeroy, Kenneth R

    Community health assessment and community health improvement planning are continuous, systematic processes for assessing and addressing health needs in a community. Since there are different models to guide assessment and planning, as well as a variety of organizations and agencies that carry out these activities, there may be confusion in choosing among approaches. By examining the various components of the different assessment and planning models, we are able to identify areas for coordination, ways to maximize collaboration, and strategies to further improve community health. We identified 11 common assessment and planning components across 18 models and requirements, with a particular focus on health department, health system, and hospital models and requirements. These common components included preplanning; developing partnerships; developing vision and scope; collecting, analyzing, and interpreting data; identifying community assets; identifying priorities; developing and implementing an intervention plan; developing and implementing an evaluation plan; communicating and receiving feedback on the assessment findings and/or the plan; planning for sustainability; and celebrating success. Within several of these components, we discuss characteristics that are critical to improving community health. Practice implications include better understanding of different models and requirements by health departments, hospitals, and others involved in assessment and planning to improve cross-sector collaboration, collective impact, and community health. In addition, federal and state policy and accreditation requirements may be revised or implemented to better facilitate assessment and planning collaboration between health departments, hospitals, and others for the purpose of improving community health.

  14. Improving students’ mathematical critical thinking through rigorous teaching and learning model with informal argument

    Science.gov (United States)

    Hamid, H.

    2018-01-01

    The purpose of this study is to analyze an improvement of students’ mathematical critical thinking (CT) ability in Real Analysis course by using Rigorous Teaching and Learning (RTL) model with informal argument. In addition, this research also attempted to understand students’ CT on their initial mathematical ability (IMA). This study was conducted at a private university in academic year 2015/2016. The study employed the quasi-experimental method with pretest-posttest control group design. The participants of the study were 83 students in which 43 students were in the experimental group and 40 students were in the control group. The finding of the study showed that students in experimental group outperformed students in control group on mathematical CT ability based on their IMA (high, medium, low) in learning Real Analysis. In addition, based on medium IMA the improvement of mathematical CT ability of students who were exposed to RTL model with informal argument was greater than that of students who were exposed to CI (conventional instruction). There was also no effect of interaction between RTL model and CI model with both (high, medium, and low) IMA increased mathematical CT ability. Finally, based on (high, medium, and low) IMA there was a significant improvement in the achievement of all indicators of mathematical CT ability of students who were exposed to RTL model with informal argument than that of students who were exposed to CI.

  15. Liquid-liquid critical point in a simple analytical model of water

    Science.gov (United States)

    Urbic, Tomaz

    2016-10-01

    A statistical model for a simple three-dimensional Mercedes-Benz model of water was used to study phase diagrams. This model on a simple level describes the thermal and volumetric properties of waterlike molecules. A molecule is presented as a soft sphere with four directions in which hydrogen bonds can be formed. Two neighboring waters can interact through a van der Waals interaction or an orientation-dependent hydrogen-bonding interaction. For pure water, we explored properties such as molar volume, density, heat capacity, thermal expansion coefficient, and isothermal compressibility and found that the volumetric and thermal properties follow the same trends with temperature as in real water and are in good general agreement with Monte Carlo simulations. The model exhibits also two critical points for liquid-gas transition and transition between low-density and high-density fluid. Coexistence curves and a Widom line for the maximum and minimum in thermal expansion coefficient divides the phase space of the model into three parts: in one part we have gas region, in the second a high-density liquid, and the third region contains low-density liquid.

  16. Modelling Framework for the Identification of Critical Variables and Parameters under Uncertainty in the Bioethanol Production from Lignocellulose

    DEFF Research Database (Denmark)

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

    2011-01-01

    This study presents the development of a systematic modelling framework for identification of the most critical variables and parameters under uncertainty, evaluated on a lignocellulosic ethanol production case study. The systematic framework starts with: (1) definition of the objectives; (2...

  17. Results from evaluations of models and cost-effectiveness tools to support introduction decisions for new vaccines need critical appraisal

    Directory of Open Access Journals (Sweden)

    Moorthy Vasee

    2011-05-01

    Full Text Available Abstract The World Health Organization (WHO recommends that the cost-effectiveness (CE of introducing new vaccines be considered before such a programme is implemented. However, in low- and middle-income countries (LMICs, it is often challenging to perform and interpret the results of model-based economic appraisals of vaccines that benefit from locally relevant data. As a result, WHO embarked on a series of consultations to assess economic analytical tools to support vaccine introduction decisions for pneumococcal, rotavirus and human papillomavirus vaccines. The objectives of these assessments are to provide decision makers with a menu of existing CE tools for vaccines and their characteristics rather than to endorse the use of a single tool. The outcome will provide policy makers in LMICs with information about the feasibility of applying these models to inform their own decision making. We argue that if models and CE analyses are used to inform decisions, they ought to be critically appraised beforehand, including a transparent evaluation of their structure, assumptions and data sources (in isolation or in comparison to similar tools, so that decision makers can use them while being fully aware of their robustness and limitations.

  18. LEARNING CYCLE-7E MODEL TO INCREASE STUDENT’S CRITICAL THINKING ON SCIENCE

    Directory of Open Access Journals (Sweden)

    Hartono -

    2013-01-01

    Full Text Available Penelitian ini bertujuan untuk memperoleh model pembelajaran Learning Cycle-7E  yang dapat meningkatkan kemampuan berpikir kritis siswa dan menuntaskan hasil belajar siswa SMPN 21 Semarang terhadap matapelajaran IPA. Penelitian PTK ini dilaksanakan dalam dua siklus. Siklus pertama belum menunjukkan peningkatan yang maksimum. Aktivitas bertanya kepada guru, keseriusan melaksanakan tugas, dan persiapan dalam mengikuti pelajaran masih pada kategori sedang. Ketuntasan belajar secara individual dan klasikal belum memenuhi kriteria yang ditetapkan. Oleh sebab itu, aktivitas ini menjadi fokus perbaikan pada siklus berikutnya. Hasil pada siklus ke-dua menunjukkan peningkatan yang signifikan. Kemampuan berpikir kritis telah tumbuh, aktivitas bertanya pada guru dan keseriusan dalam melaksanakan tugas meningkat pada kategori tinggi. Ketuntasan belajar klasikal sebesar 79%, melebihi kriteria keberhasilan tindakan yang ditetapkan pada penelitian ini yaitu sebesar 75%. Hal ini berarti bahwa model pembelajaran Learning Cycle-7E dapat meningkatkan kemampuan berpikir kritis siswa, tanpa mengganggu hasil belajar kognitifnya. This research aimed to increase the students’ critical thinking by designing Learning Cycle- 7E which is suitable with the criteria set out in SJHS 21 Semarang. Thisclassroom action research was carried out in two cycles. In cycle-I, the students’ critical thinking was growing but not maximum, their activity during learning process was in medium category. That is why there were several aspects of students’ activity that need to be investigated. They were the students’courage to ask the teacher, their seriousness to do the assignments, and their readiness to learn as well as to prepare a question prior learning. The students’ average cognitive learning outcomes and the classical learning outcomes were not very satisfied. The result of the cycle-II showed a significant improvements. The students

  19. Information modelling and semantic linking for a software workbench for interactive, time critical and self-adaptive cloud applications

    NARCIS (Netherlands)

    Martin, P.; Taal, A.; Quevedo, F.; Rogers, D.; Evans, K.; Jones, A.; Stankovski, V.; Taherizadeh, S.; Trnkoczy, J.; Suciu, G.; Zhao, Z.; Barolli, L.; Takizawa, M.; Enokido, T.; Jara, A.J.; Bocchi, Y.

    2016-01-01

    Cloud environments can provide elastic, controllable on-demand services for supporting complex distributed applications. However the engineering methods and software tools used for developing, deploying and executing classical time-critical applications do not, as yet, account for the

  20. Can Earth System Model Provide Reasonable Natural Runoff Estimates to Support Water Management Studies?

    Science.gov (United States)

    Kao, S. C.; Shi, X.; Kumar, J.; Ricciuto, D. M.; Mao, J.; Thornton, P. E.

    2017-12-01

    With the concern of changing hydrologic regime, there is a crucial need to better understand how water availability may change and influence water management decisions in the projected future climate conditions. Despite that surface hydrology has long been simulated by land model within the Earth System modeling (ESM) framework, given the coarser horizontal resolution and lack of engineering-level calibration, raw runoff from ESM is generally discarded by water resource managers when conducting hydro-climate impact assessments. To identify a likely path to improve the credibility of ESM-simulated natural runoff, we conducted regional model simulation using the land component (ALM) of the Accelerated Climate Modeling for Energy (ACME) version 1 focusing on the conterminous United States (CONUS). Two very different forcing data sets, including (1) the conventional 0.5° CRUNCEP (v5, 1901-2013) and (2) the 1-km Daymet (v3, 1980-2013) aggregated to 0.5°, were used to conduct 20th century transient simulation with satellite phenology. Additional meteorologic and hydrologic observations, including PRISM precipitation and U.S. Geological Survey WaterWatch runoff, were used for model evaluation. For various CONUS hydrologic regions (such as Pacific Northwest), we found that Daymet can significantly improve the reasonableness of simulated ALM runoff even without intensive calibration. The large dry bias of CRUNCEP precipitation (evaluated by PRISM) in multiple CONUS hydrologic regions is believed to be the main reason causing runoff underestimation. The results suggest that when driving with skillful precipitation estimates, ESM has the ability to produce reasonable natural runoff estimates to support further water management studies. Nevertheless, model calibration will be required for regions (such as Upper Colorado) where ill performance is showed for multiple different forcings.

  1. The Roy Adaptation Model: A Theoretical Framework for Nurses Providing Care to Individuals With Anorexia Nervosa.

    Science.gov (United States)

    Jennings, Karen M

    Using a nursing theoretical framework to understand, elucidate, and propose nursing research is fundamental to knowledge development. This article presents the Roy Adaptation Model as a theoretical framework to better understand individuals with anorexia nervosa during acute treatment, and the role of nursing assessments and interventions in the promotion of weight restoration. Nursing assessments and interventions situated within the Roy Adaptation Model take into consideration how weight restoration does not occur in isolation but rather reflects an adaptive process within external and internal environments, and has the potential for more holistic care.

  2. The anti-human trafficking collaboration model and serving victims: Providers' perspectives on the impact and experience.

    Science.gov (United States)

    Kim, Hea-Won; Park, Taekyung; Quiring, Stephanie; Barrett, Diana

    2018-01-01

    A coalition model is often used to serve victims of human trafficking but little is known about whether the model is adequately meeting the needs of the victims. The purpose of this study was to examine anti-human trafficking collaboration model in terms of its impact and the collaborative experience, including challenges and lessons learned from the service providers' perspective. Mixed methods study was conducted to evaluate the impact of a citywide anti-trafficking coalition model from the providers' perspectives. Web-based survey was administered with service providers (n = 32) and focus groups were conducted with Core Group members (n = 10). Providers reported the coalition model has made important impacts in the community by increasing coordination among the key agencies, law enforcement, and service providers and improving quality of service provision. Providers identified the improved and expanded partnerships among coalition members as the key contributing factor to the success of the coalition model. Several key strategies were suggested to improve the coalition model: improved referral tracking, key partner and protocol development, and information sharing.

  3. Uncertainties in modelling and scaling of critical flows and pump model in TRAC-PF1/MOD1

    International Nuclear Information System (INIS)

    Rohatgi, U.S.; Yu, Wen-Shi.

    1987-01-01

    The USNRC has established a Code Scalability, Applicability and Uncertainty (CSAU) evaluation methodology to quantify the uncertainty in the prediction of safety parameters by the best estimate codes. These codes can then be applied to evaluate the Emergency Core Cooling System (ECCS). The TRAC-PF1/MOD1 version was selected as the first code to undergo the CSAU analysis for LBLOCA applications. It was established through this methodology that break flow and pump models are among the top ranked models in the code affecting the peak clad temperature (PCT) prediction for LBLOCA. The break flow model bias or discrepancy and the uncertainty were determined by modelling the test section near the break for 12 Marviken tests. It was observed that the TRAC-PF1/MOD1 code consistently underpredicts the break flow rate and that the prediction improved with increasing pipe length (larger L/D). This is true for both subcooled and two-phase critical flows. A pump model was developed from Westinghouse (1/3 scale) data. The data represent the largest available test pump relevant to Westinghouse PWRs. It was then shown through the analysis of CE and CREARE pump data that larger pumps degrade less and also that pumps degrade less at higher pressures. Since the model developed here is based on the 1/3 scale pump and on low pressure data, it is conservative and will overpredict the degradation when applied to PWRs

  4. Retrieving Backbone String Neighbors Provides Insights Into Structural Modeling of Membrane Proteins*

    Science.gov (United States)

    Sun, Jiang-Ming; Li, Tong-Hua; Cong, Pei-Sheng; Tang, Sheng-Nan; Xiong, Wen-Wei

    2012-01-01

    Identification of protein structural neighbors to a query is fundamental in structure and function prediction. Here we present BS-align, a systematic method to retrieve backbone string neighbors from primary sequences as templates for protein modeling. The backbone conformation of a protein is represented by the backbone string, as defined in Ramachandran space. The backbone string of a query can be accurately predicted by two innovative technologies: a knowledge-driven sequence alignment and encoding of a backbone string element profile. Then, the predicted backbone string is employed to align against a backbone string database and retrieve a set of backbone string neighbors. The backbone string neighbors were shown to be close to native structures of query proteins. BS-align was successfully employed to predict models of 10 membrane proteins with lengths ranging between 229 and 595 residues, and whose high-resolution structural determinations were difficult to elucidate both by experiment and prediction. The obtained TM-scores and root mean square deviations of the models confirmed that the models based on the backbone string neighbors retrieved by the BS-align were very close to the native membrane structures although the query and the neighbor shared a very low sequence identity. The backbone string system represents a new road for the prediction of protein structure from sequence, and suggests that the similarity of the backbone string would be more informative than describing a protein as belonging to a fold. PMID:22415040

  5. Retrieving backbone string neighbors provides insights into structural modeling of membrane proteins.

    Science.gov (United States)

    Sun, Jiang-Ming; Li, Tong-Hua; Cong, Pei-Sheng; Tang, Sheng-Nan; Xiong, Wen-Wei

    2012-07-01

    Identification of protein structural neighbors to a query is fundamental in structure and function prediction. Here we present BS-align, a systematic method to retrieve backbone string neighbors from primary sequences as templates for protein modeling. The backbone conformation of a protein is represented by the backbone string, as defined in Ramachandran space. The backbone string of a query can be accurately predicted by two innovative technologies: a knowledge-driven sequence alignment and encoding of a backbone string element profile. Then, the predicted backbone string is employed to align against a backbone string database and retrieve a set of backbone string neighbors. The backbone string neighbors were shown to be close to native structures of query proteins. BS-align was successfully employed to predict models of 10 membrane proteins with lengths ranging between 229 and 595 residues, and whose high-resolution structural determinations were difficult to elucidate both by experiment and prediction. The obtained TM-scores and root mean square deviations of the models confirmed that the models based on the backbone string neighbors retrieved by the BS-align were very close to the native membrane structures although the query and the neighbor shared a very low sequence identity. The backbone string system represents a new road for the prediction of protein structure from sequence, and suggests that the similarity of the backbone string would be more informative than describing a protein as belonging to a fold.

  6. A Context-Aware Model to Provide Positioning in Disaster Relief Scenarios

    Directory of Open Access Journals (Sweden)

    Daniel Moreno

    2015-09-01

    Full Text Available The effectiveness of the work performed during disaster relief efforts is highly dependent on the coordination of activities conducted by the first responders deployed in the affected area. Such coordination, in turn, depends on an appropriate management of geo-referenced information. Therefore, enabling first responders to count on positioning capabilities during these activities is vital to increase the effectiveness of the response process. The positioning methods used in this scenario must assume a lack of infrastructure-based communication and electrical energy, which usually characterizes affected areas. Although positioning systems such as the Global Positioning System (GPS have been shown to be useful, we cannot assume that all devices deployed in the area (or most of them will have positioning capabilities by themselves. Typically, many first responders carry devices that are not capable of performing positioning on their own, but that require such a service. In order to help increase the positioning capability of first responders in disaster-affected areas, this paper presents a context-aware positioning model that allows mobile devices to estimate their position based on information gathered from their surroundings. The performance of the proposed model was evaluated using simulations, and the obtained results show that mobile devices without positioning capabilities were able to use the model to estimate their position. Moreover, the accuracy of the positioning model has been shown to be suitable for conducting most first response activities.

  7. Neutron Scattering Provides a New Model for Optimal Morphologies in Organic Photovoltaics: Rivers and Streams

    Science.gov (United States)

    Dadmun, Mark; Henry, Nathan; Yin, Wen; Xiao, Kai; Ankner, John

    2011-03-01

    The current model for the ideal morphology of a conjugated polymer bulk heterojunction organic photovoltaic (OPV) is a phase-separated structure that consists of two pure phases, one an electron donor, the other an acceptor, that form an interpenetrating, bicontinuous, network on the length scale of 10-20 nm. In this talk, neutron scattering experiments that demonstrate that this model is incorrect for the archetypal conjugated polymer bulk heterojunction, poly[3-hexylthiophene] (P3HT) and the fullerene 1-(3-methyloxycarbonyl)propy(1-phenyl [6,6]) C61 (PCBM) will be presented. These studies show that the miscibility of PCBM in P3HT approaches 20 wt%, a result that is counter to the standard model of efficient organic photovoltaics. The implications of this finding on the ideal morphology of conjugated polymer bulk heterojunctions will be discussed, where these results are interpreted to present a model that agrees with this data, and conforms to structural and functional information in the literature. Furthermore, the thermodynamics of conjugated polymer:fullerene mixtures dominate the formation of this hierarchical morphology and must be more thoroughly understood to rationally design and fabricate optimum morphologies for OPV activity.

  8. The Strategic Thinking and Learning Community: An Innovative Model for Providing Academic Assistance

    Science.gov (United States)

    Commander, Nannette Evans; Valeri-Gold, Maria; Darnell, Kim

    2004-01-01

    Today, academic assistance efforts are frequently geared to all students, not just the underprepared, with study skills offered in various formats. In this article, the authors describe a learning community model with the theme, "Strategic Thinking and Learning" (STL). Results of data analysis indicate that participants of the STL…

  9. Models Provide Specificity: Testing a Proposed Mechanism of Visual Working Memory Capacity Development

    Science.gov (United States)

    Simmering, Vanessa R.; Patterson, Rebecca

    2012-01-01

    Numerous studies have established that visual working memory has a limited capacity that increases during childhood. However, debate continues over the source of capacity limits and its developmental increase. Simmering (2008) adapted a computational model of spatial cognitive development, the Dynamic Field Theory, to explain not only the source…

  10. The "P2P" Educational Model Providing Innovative Learning by Linking Technology, Business and Research

    Science.gov (United States)

    Dickinson, Paul Gordon

    2017-01-01

    This paper evaluates the effect and potential of a new educational learning model called Peer to Peer (P2P). The study was focused on Laurea, Hyvinkaa's Finland campus and its response to bridging the gap between traditional educational methods and working reality, where modern technology plays an important role. The study describes and evaluates…

  11. Identifying critical nitrogen application rate for maize yield and nitrate leaching in a Haplic Luvisol soil using the DNDC model.

    Science.gov (United States)

    Zhang, Yitao; Wang, Hongyuan; Liu, Shen; Lei, Qiuliang; Liu, Jian; He, Jianqiang; Zhai, Limei; Ren, Tianzhi; Liu, Hongbin

    2015-05-01

    Identification of critical nitrogen (N) application rate can provide management supports for ensuring grain yield and reducing amount of nitrate leaching to ground water. A five-year (2008-2012) field lysimeter (1 m × 2 m × 1.2 m) experiment with three N treatments (0, 180 and 240 kg Nha(-1)) was conducted to quantify maize yields and amount of nitrate leaching from a Haplic Luvisol soil in the North China Plain. The experimental data were used to calibrate and validate the process-based model of Denitrification-Decomposition (DNDC). After this, the model was used to simulate maize yield production and amount of nitrate leaching under a series of N application rates and to identify critical N application rate based on acceptable yield and amount of nitrate leaching for this cropping system. The results of model calibration and validation indicated that the model could correctly simulate maize yield and amount of nitrate leaching, with satisfactory values of RMSE-observation standard deviation ratio, model efficiency and determination coefficient. The model simulations confirmed the measurements that N application increased maize yield compared with the control, but the high N rate (240 kg Nha(-1)) did not produce more yield than the low one (120 kg Nha(-1)), and that the amount of nitrate leaching increased with increasing N application rate. The simulation results suggested that the optimal N application rate was in a range between 150 and 240 kg ha(-1), which would keep the amount of nitrate leaching below 18.4 kg NO₃(-)-Nha(-1) and meanwhile maintain acceptable maize yield above 9410 kg ha(-1). Furthermore, 180 kg Nha(-1) produced the highest yields (9837 kg ha(-1)) and comparatively lower amount of nitrate leaching (10.0 kg NO₃(-)-Nha(-1)). This study will provide a valuable reference for determining optimal N application rate (or range) in other crop systems and regions in China. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Using Model-Based System Engineering to Provide Artifacts for NASA Project Life-Cycle and Technical Reviews Presentation

    Science.gov (United States)

    Parrott, Edith L.; Weiland, Karen J.

    2017-01-01

    This is the presentation for the AIAA Space conference in September 2017. It highlights key information from Using Model-Based Systems Engineering to Provide Artifacts for NASA Project Life-cycle and Technical Reviews paper.

  13. Segmentation of 3d Models for Cultural Heritage Structural Analysis - Some Critical Issues

    Science.gov (United States)

    Gonizzi Barsanti, S.; Guidi, G.; De Luca, L.

    2017-08-01

    Cultural Heritage documentation and preservation has become a fundamental concern in this historical period. 3D modelling offers a perfect aid to record ancient buildings and artefacts and can be used as a valid starting point for restoration, conservation and structural analysis, which can be performed by using Finite Element Methods (FEA). The models derived from reality-based techniques, made up of the exterior surfaces of the objects captured at high resolution, are - for this reason - made of millions of polygons. Such meshes are not directly usable in structural analysis packages and need to be properly pre-processed in order to be transformed in volumetric meshes suitable for FEA. In addition, dealing with ancient objects, a proper segmentation of 3D volumetric models is needed to analyse the behaviour of the structure with the most suitable level of detail for the different sections of the structure under analysis. Segmentation of 3D models is still an open issue, especially when dealing with ancient, complicated and geometrically complex objects that imply the presence of anomalies and gaps, due to environmental agents such as earthquakes, pollution, wind and rain, or human factors. The aims of this paper is to critically analyse some of the different methodologies and algorithms available to segment a 3D point cloud or a mesh, identifying difficulties and problems by showing examples on different structures.

  14. [Endocrine disruptors : Evidence from epidemiological studies necessitates a critical review of model systems].

    Science.gov (United States)

    Hoffmann, M; Gebauer, S; Nüchter, M; Baber, R; Ried, J; von Bergen, M; Kiess, W

    2017-06-01

    Endocrine disruptive chemicals (EDCs) cause adverse health effects through interaction with endocrine systems. They are classified by chemical structure, effects on specific endocrine systems, bioaccumulation, persistence in the environment, or clinically observable effects. For research of the complex mechanisms of action in the human body, only in vitro model systems have so far been available, that have insufficient high-throughput capacity, which makes risk evaluation more difficult. In addition, in industrial nations, living people are often exposed to mixtures of substances, with various effects. The clinical importance of epigenetic changes caused by the action of EDCs during vulnerable phases of development is currently unclear. Epidemiological studies are criticized because reproducibility is not always guaranteed. Nevertheless, they remain the method of choice for the development and analysis of suitable model systems. Positive associations, in spite of sometimes conflicting results, are key in the selection of factors that can then be analysed in model systems in an unbiased way. This article depicts the mainly positive epidemiological findings for EDC-caused effects in the fields of growth and metabolism, neurocognitive development and sexual development and reproduction. As a result, there is a need for closer linkage between epidemiological studies and mechanistic research into model systems, especially focusing on the interaction of different EDCs and the consequences of prenatal and early life exposure.

  15. Descriptive and Critical Review of Multiregional Econometric Models of the United States

    OpenAIRE

    Herman, Amy L.

    1984-01-01

    Many methodological tools exist for use by regional planners and policy analysts concerned with the implications of federal and regional policies for regional economies. Regional and multire­ gional econometric models represent a class of such tools not widely available for public use outside their institutional settings. The purpose of such models is to provide economic forecasting and policy simulations with analytic flexibility. Accordingly, the methods employed in developing econometric m...

  16. Analysis of Critical Issues in Biosphere Assessment Modelling and Site Investigation

    Energy Technology Data Exchange (ETDEWEB)

    Egan, M.J.; Thorne, M.C.; Little, R.H.; Pasco, R.F. [Quintessa Limited, Henley-on-Thames (United Kingdom)

    2003-07-01

    The aim of this document is to present a critical review of issues concerned with the treatment of the biosphere and geosphere-biosphere interface in long-term performance assessment studies for nuclear waste disposal in Sweden. The review covers three main areas of investigation: a review of SKB's plans for undertaking site investigations at candidate locations for the development of a deep geological repository for spent fuel; identification of critical uncertainties associated with SKB's treatment of the geosphere-biosphere interface in recent performance assessments; and a preliminary modelling investigation of the significance of features, events and processes in the near-surface environment in terms of their effect on the accumulation and redistribution of radionuclides at the geosphere-biosphere interface. Overall, SKB's proposals for site investigations are considered to be comprehensive and, if they can be carried out to the specification presented, will constitute a benchmark that other waste management organisations will have to work hard to emulate. The main concern is that expertise for undertaking the investigations and reporting the results could be stretched very thin. The authors have also identified weaknesses in the documentation concerning the collection of evidence for environmental change and on developing scenarios for future environmental change. A fundamental assumption adopted in the renewed assessment of the SFR 1 repository, which is not discussed or justified in any of the documentation that has been reviewed, is that radionuclides enter the water column of the coastal and lake models directly, without passing first through the bed sediments. The modelling study reported herein suggests that SKB's models are robust to range of alternative conceptual descriptions relating to the geosphere-biosphere interface. There are however situations, in which contaminated groundwater is released via sediment rather than directly

  17. Continuous Automated Model EvaluatiOn (CAMEO) complementing the critical assessment of structure prediction in CASP12.

    Science.gov (United States)

    Haas, Jürgen; Barbato, Alessandro; Behringer, Dario; Studer, Gabriel; Roth, Steven; Bertoni, Martino; Mostaguir, Khaled; Gumienny, Rafal; Schwede, Torsten

    2018-03-01

    Every second year, the community experiment "Critical Assessment of Techniques for Structure Prediction" (CASP) is conducting an independent blind assessment of structure prediction methods, providing a framework for comparing the performance of different approaches and discussing the latest developments in the field. Yet, developers of automated computational modeling methods clearly benefit from more frequent evaluations based on larger sets of data. The "Continuous Automated Model EvaluatiOn (CAMEO)" platform complements the CASP experiment by conducting fully automated blind prediction assessments based on the weekly pre-release of sequences of those structures, which are going to be published in the next release of the PDB Protein Data Bank. CAMEO publishes weekly benchmarking results based on models collected during a 4-day prediction window, on average assessing ca. 100 targets during a time frame of 5 weeks. CAMEO benchmarking data is generated consistently for all participating methods at the same point in time, enabling developers to benchmark and cross-validate their method's performance, and directly refer to the benchmarking results in publications. In order to facilitate server development and promote shorter release cycles, CAMEO sends weekly email with submission statistics and low performance warnings. Many participants of CASP have successfully employed CAMEO when preparing their methods for upcoming community experiments. CAMEO offers a variety of scores to allow benchmarking diverse aspects of structure prediction methods. By introducing new scoring schemes, CAMEO facilitates new development in areas of active research, for example, modeling quaternary structure, complexes, or ligand binding sites. © 2017 Wiley Periodicals, Inc.

  18. Model of a multiverse providing the dark energy of our universe

    Science.gov (United States)

    Rebhan, E.

    2017-09-01

    It is shown that the dark energy presently observed in our universe can be regarded as the energy of a scalar field driving an inflation-like expansion of a multiverse with ours being a subuniverse among other parallel universes. A simple model of this multiverse is elaborated: Assuming closed space geometry, the origin of the multiverse can be explained by quantum tunneling from nothing; subuniverses are supposed to emerge from local fluctuations of separate inflation fields. The standard concept of tunneling from nothing is extended to the effect that in addition to an inflationary scalar field, matter is also generated, and that the tunneling leads to an (unstable) equilibrium state. The cosmological principle is assumed to pertain from the origin of the multiverse until the first subuniverses emerge. With increasing age of the multiverse, its spatial curvature decays exponentially so fast that, due to sharing the same space, the flatness problem of our universe resolves by itself. The dark energy density imprinted by the multiverse on our universe is time-dependent, but such that the ratio w = ϱ/(c2p) of its mass density and pressure (times c2) is time-independent and assumes a value - 1 + 𝜖 with arbitrary 𝜖 > 0. 𝜖 can be chosen so small, that the dark energy model of this paper can be fitted to the current observational data as well as the cosmological constant model.

  19. Using an established telehealth model to train urban primary care providers on hypertension management.

    Science.gov (United States)

    Masi, Christopher; Hamlish, Tamara; Davis, Andrew; Bordenave, Kristine; Brown, Stephen; Perea, Brenda; Aduana, Glen; Wolfe, Marcus; Bakris, George; Johnson, Daniel

    2012-01-01

    The objective of this study was to determine whether a videoconference-based telehealth network can increase hypertension management knowledge and self-assessed competency among primary care providers (PCPs) working in urban Federally Qualified Health Centers (FQHCs). We created a telehealth network among 6 urban FQHCs and our institution to support a 12-session educational program designed to teach state-of-the-art hypertension management. Each 1-hour session included a brief lecture by a university-based hypertension specialist, case presentations by PCPs, and interactive discussions among the specialist and PCPs. Twelve PCPs (9 intervention and 3 controls) were surveyed at baseline and immediately following the curriculum. The mean number of correct answers on the 26-item hypertension knowledge questionnaire increased in the intervention group (13.11 [standard deviation (SD)]=3.06) to 17.44 [SD=1.59], Phypertension management self-assessed competency scale increased in the intervention group (4.68 [SD=0.94] to 5.41 [SD=0.89], Phypertension care provided by urban FQHC providers. © 2011 Wiley Periodicals, Inc.

  20. Do NHS walk-in centres in England provide a model of integrated care?

    Directory of Open Access Journals (Sweden)

    C. Salisbury

    2003-08-01

    Full Text Available Purpose: To undertake a comprehensive evaluation of NHS walk-in centres against criteria of improved access, quality, user satisfaction and efficiency. Context: Forty NHS walk-in centres have been opened in England, as part of the UK governments agenda to modernise the NHS. They are intended to improve access to primary care, provide high quality treatment at convenient times, and reduce inappropriate demand on other NHS providers. Care is provided by nurses rather than doctors, using computerised algorithms, and nurses use protocols to supply treatments previously only available from doctors. Data sources: Several linked studies were conducted using different sources of data and methodologies. These included routinely collected data, site visits, patient interviews, a survey of users of walk-in centres, a study using simulated patients to assess quality of care, analysis of consultation rates in NHS services near to walk-in centres, and audit of compliance with protocols. Conclusion & discussion: The findings illustrate many of the issues described in a recent WHO reflective paper on Integrated Care, including tensions between professional judgement and use of protocols, problems with incompatible IT systems, balancing users' demands and needs, the importance of understanding health professionals' roles and issues of technical versus allocative efficiency.