WorldWideScience

Sample records for current theoretical approaches

  1. Expectation values of flavor-neutrino currents in field theoretical approach to oscillation problem -- formulation

    CERN Document Server

    Fujii, Kanji; Fujii, Kanji; Shimomura, Takashi

    2004-01-01

    As a possible approach to the neutrino oscillation on the basis of quantum field theory, the expectation values of the flavor-neutrino currents are investigated by employing the finite-time transition matrix in the interaction representation. Such expectation values give us in the simplest form a possible way of treating the neutrino oscillation without recourse to any one flavor-neutrino states. The present paper is devoted to presenting the formulation and the main structures of the relevant expectation values.

  2. Expectation values of flavor-neutrino currents in field theoretical approach to oscillation problem -- formulation

    OpenAIRE

    FUJII, Kanji; Shimomura, Takashi

    2004-01-01

    As a possible approach to the neutrino oscillation on the basis of quantum field theory, the expectation values of the flavor-neutrino currents are investigated by employing the finite-time transition matrix in the interaction representation. Such expectation values give us in the simplest form a possible way of treating the neutrino oscillation without recourse to any one flavor-neutrino states. The present paper is devoted to presenting the formulation and the main structures of the relevan...

  3. Neurocognitive and Social Cognitive Approaches for Improving Functional Outcome in Early Psychosis: Theoretical Considerations and Current State of Evidence

    Directory of Open Access Journals (Sweden)

    Cali F. Bartholomeusz

    2012-01-01

    Full Text Available Improving functional outcome, in addition to alleviating psychotic symptoms, is now a major treatment objective in schizophrenia research. Given the large body of evidence suggesting pharmacological treatments generally have minimal effects on indices of functioning, research has turned to psychosocial rehabilitation programs. Among these, neurocognitive and social cognitive interventions are at the forefront of this field and are argued to target core deficits inherent to the schizophrenia illness. However, to date, research trials have primarily focused on chronic schizophrenia populations, neglecting the early psychosis groups who are often as severely impaired in social and occupational functioning. This theoretical paper will outline the rationale for investigating adjunctive cognitive-based interventions in the early phases of psychotic illness, critically examine the current approach strategies used in these interventions, and assess the evidence supporting certain training programs for improving functional outcome in early psychosis. Potential pathways for future research will be discussed.

  4. Theoretical Approaches to Coping

    Directory of Open Access Journals (Sweden)

    Sofia Zyga

    2013-01-01

    Full Text Available Introduction: Dealing with stress requires conscious effort, it cannot be perceived as equal to individual's spontaneous reactions. The intentional management of stress must not be confused withdefense mechanisms. Coping differs from adjustment in that the latter is more general, has a broader meaning and includes diverse ways of facing a difficulty.Aim: An exploration of the definition of the term "coping", the function of the coping process as well as its differentiation from other similar meanings through a literature review.Methodology: Three theoretical approaches of coping are introduced; the psychoanalytic approach; approaching by characteristics; and the Lazarus and Folkman interactive model.Results: The strategic methods of the coping approaches are described and the article ends with a review of the approaches including the functioning of the stress-coping process , the classificationtypes of coping strategies in stress-inducing situations and with a criticism of coping approaches.Conclusions: The comparison of coping in different situations is difficult, if not impossible. The coping process is a slow process, so an individual may select one method of coping under one set ofcircumstances and a different strategy at some other time. Such selection of strategies takes place as the situation changes.

  5. Theoretical approaches to elections defining

    Directory of Open Access Journals (Sweden)

    Natalya V. Lebedeva

    2011-01-01

    Full Text Available Theoretical approaches to elections defining develop the nature, essence and content of elections, help to determine their place and a role as one of the major national law institutions in democratic system.

  6. THEORETICAL APPROACHES IN INTERNATIONAL RELATIONS ...

    African Journals Online (AJOL)

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    understanding of the social dynamics of the world we live in. Theoretical approaches are also instrumental in shaping perceptions of what matters in international politics ... This implies that, as a technique of last resort, the military instrument.

  7. Theoretical Approaches to Political Communication.

    Science.gov (United States)

    Chesebro, James W.

    Political communication appears to be emerging as a theoretical and methodological academic area of research within both speech-communication and political science. Five complimentary approaches to political science (Machiavellian, iconic, ritualistic, confirmational, and dramatistic) may be viewed as a series of variations which emphasize the…

  8. Psicología pastoral. Aproximaciones teóricas y tendencias actuales (pastoral psychology, theoretical approaches, and current tendencies

    Directory of Open Access Journals (Sweden)

    Enrique León Arbelaéz Castaño

    2014-12-01

    Full Text Available RESUMEN: El presente artículo pretende mostrar la importancia que en los últimos tiempos ha cobrado la psicología en el ámbito de la pastoral, y es por esto que se hará un recuento de los principales autores que han abordado este tema, para luego adentrarnos en aspectos psicopatológicos que se aplican a este campo. ABSTRACT: This current article aims to show the importance that, in the last few years, psychology has had in the pastoral setting, and that is why an inventory of the main authors, in this issue, will be made. Then, we will go into some psychopathological aspects, which apply in this field

  9. Theoretical approaches to superionic conductivity

    Indian Academy of Sciences (India)

    C S Sunandana; P Senthil Kumar

    2004-02-01

    Recent theoretical approaches to the understanding of superionic conductivity in polycrystalline, glassy and polymeric materials are briefly reviewed. Phase transitions to the superionic conducting state in the AgI family are apparently triggered by cluster formation and strong mobile ion interaction within the clusters. Anomalous conductivity and related physical properties are explained in the cluster induced distortion model. Ionic composites such as AgX : Al2O3 ( = Cl, Br and I) involve conducting and non-conducting phases and the all-important interface between the two whose space charge enhances the conductivity and also trigger phase transitions to exotic polymorphic phases, for which the mechanisms are yet to be explored. Ion hopping dynamics controls the conductivity of superionic glasses. Mode coupling and jump relaxation theories account for the non-Debye relaxation observed in a.c. conductivity of these glasses. The theory of conductivity in polymer electrolytes-still in its infancy-involves their complex structure and glass transition behaviour. Preparative and thermal history, composition and crystallinity control ionic conductivity. New approaches to the synthesis of optimal polymer electrolytes such as rubbery electrolytes, crystalline polymers and nanocomposites must be considered before achieving a comprehensive theoretical understanding.

  10. Group theoretical approach to entanglement

    CERN Document Server

    Korbicz, J K

    2006-01-01

    We examine a potential relevance of methods of harmonic analysis for the study of quantum entanglement. By changing the mathematical object representing quantum states, we reformulate the separability problem in group-theoretical terms. We also translate the positivity of partial transpose (PPT) criterion and one of the necessary-and-sufficient criteria for pure states to the group-theoretical language. The formal relation of our formalism to local hidden variable models is briefly examined. We also remark on the connection between entanglement and some certain non-commutativity.

  11. Machine learning a theoretical approach

    CERN Document Server

    Natarajan, Balas K

    2014-01-01

    This is the first comprehensive introduction to computational learning theory. The author's uniform presentation of fundamental results and their applications offers AI researchers a theoretical perspective on the problems they study. The book presents tools for the analysis of probabilistic models of learning, tools that crisply classify what is and is not efficiently learnable. After a general introduction to Valiant's PAC paradigm and the important notion of the Vapnik-Chervonenkis dimension, the author explores specific topics such as finite automata and neural networks. The presentation

  12. A Set Theoretical Approach to Maturity Models

    DEFF Research Database (Denmark)

    Lasrado, Lester; Vatrapu, Ravi; Andersen, Kim Normann

    2016-01-01

    Maturity Model research in IS has been criticized for the lack of theoretical grounding, methodological rigor, empirical validations, and ignorance of multiple and non-linear paths to maturity. To address these criticisms, this paper proposes a novel set-theoretical approach to maturity models ch...

  13. Managerial Leadership - A Theoretical Approach

    Directory of Open Access Journals (Sweden)

    Felicia Cornelia MACARIE

    2007-06-01

    Full Text Available The paper endeavors to offer an overview of the major theories on leadership and the way in which it influences the management of contemporary organizations. Numerous scholars highlight that there are numerous overlaps between the concepts of management and leadership. This is the reason why the first section of the paper focuses on providing an extensive overview of the literature regarding the meaning of the two aforementioned concepts. The second section addresses more in depth the concept of leadership and managerial leadership and focuses on the ideal profile of the leader. The last section of the paper critically discusses various types of leadership and more specifically modern approaches to the concept and practices of leadership.

  14. UNCERTAINTY IN NEOCLASSICAL AND KEYNESIAN THEORETICAL APPROACHES: A BEHAVIOURAL PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    Sinziana BALTATESCU

    2015-11-01

    Full Text Available The ”mainstream” neoclassical assumptions about human economic behavior are currently challenged by both behavioural researches on human behaviour and other theoretical approaches which, in the context of the recent economic and financial crisis find arguments to reinforce their theoretical statements. The neoclassical “perfect rationality” assumption is most criticized and provokes the mainstream theoretical approach to efforts of revisiting the theoretical framework in order to re-state the economic models validity. Uncertainty seems, in this context, to be the concept that allows other theoretical approaches to take into consideration a more realistic individual from the psychological perspective. This paper is trying to present a comparison between the neoclassical and Keynesian approach of the uncertainty, considering the behavioural arguments and challenges addressed to the mainstream theory.

  15. Game theoretic approaches for spectrum redistribution

    CERN Document Server

    Wu, Fan

    2014-01-01

    This brief examines issues of spectrum allocation for the limited resources of radio spectrum. It uses a game-theoretic perspective, in which the nodes in the wireless network are rational and always pursue their own objectives. It provides a systematic study of the approaches that can guarantee the system's convergence at an equilibrium state, in which the system performance is optimal or sub-optimal. The author provides a short tutorial on game theory, explains game-theoretic channel allocation in clique and in multi-hop wireless networks and explores challenges in designing game-theoretic m

  16. New Theoretical Approach Integrated Education and Technology

    Science.gov (United States)

    Ding, Gang

    2010-01-01

    The paper focuses on exploring new theoretical approach in education with development of online learning technology, from e-learning to u-learning and virtual reality technology, and points out possibilities such as constructing a new teaching ecological system, ubiquitous educational awareness with ubiquitous technology, and changing the…

  17. Recent Theoretical Approaches to Minimal Artificial Cells

    Directory of Open Access Journals (Sweden)

    Fabio Mavelli

    2014-05-01

    Full Text Available Minimal artificial cells (MACs are self-assembled chemical systems able to mimic the behavior of living cells at a minimal level, i.e. to exhibit self-maintenance, self-reproduction and the capability of evolution. The bottom-up approach to the construction of MACs is mainly based on the encapsulation of chemical reacting systems inside lipid vesicles, i.e. chemical systems enclosed (compartmentalized by a double-layered lipid membrane. Several researchers are currently interested in synthesizing such simple cellular models for biotechnological purposes or for investigating origin of life scenarios. Within this context, the properties of lipid vesicles (e.g., their stability, permeability, growth dynamics, potential to host reactions or undergo division processes… play a central role, in combination with the dynamics of the encapsulated chemical or biochemical networks. Thus, from a theoretical standpoint, it is very important to develop kinetic equations in order to explore first—and specify later—the conditions that allow the robust implementation of these complex chemically reacting systems, as well as their controlled reproduction. Due to being compartmentalized in small volumes, the population of reacting molecules can be very low in terms of the number of molecules and therefore their behavior becomes highly affected by stochastic effects both in the time course of reactions and in occupancy distribution among the vesicle population. In this short review we report our mathematical approaches to model artificial cell systems in this complex scenario by giving a summary of three recent simulations studies on the topic of primitive cell (protocell systems.

  18. Information theoretic approach for accounting classification

    CERN Document Server

    Ribeiro, E M S

    2014-01-01

    In this paper we consider an information theoretic approach for the accounting classification process. We propose a matrix formalism and an algorithm for calculations of information theoretic measures associated to accounting classification. The formalism may be useful for further generalizations, and computer based implementation. Information theoretic measures, mutual information and symmetric uncertainty, were evaluated for daily transactions recorded in the chart of accounts of a small company during two years. Variation in the information measures due the aggregation of data in the process of accounting classification is observed. In particular, the symmetric uncertainty seems to be a useful parameter for comparing companies over time or in different sectors; or different accounting choices and standards.

  19. Reasoning about Action: An Argumentation - Theoretic Approach

    CERN Document Server

    Foo, N Y; 10.1613/jair.1602

    2011-01-01

    We present a uniform non-monotonic solution to the problems of reasoning about action on the basis of an argumentation-theoretic approach. Our theory is provably correct relative to a sensible minimisation policy introduced on top of a temporal propositional logic. Sophisticated problem domains can be formalised in our framework. As much attention of researchers in the field has been paid to the traditional and basic problems in reasoning about actions such as the frame, the qualification and the ramification problems, approaches to these problems within our formalisation lie at heart of the expositions presented in this paper.

  20. BEHAVIORAL INPUTS TO THE THEORETICAL APPROACH OF THE ECONOMIC CRISIS

    Directory of Open Access Journals (Sweden)

    Sinziana BALTATESCU

    2015-09-01

    Full Text Available The current economic and financial crisis gave room for the theoretical debates to reemerge. The economic reality challenged the mainstream neoclassical approach leaving the opportunity for the Austrian School, Post Keynesianism or Institutionalists to bring in front theories that seem to better explain the economic crisis and thus, leaving space for more efficient economic policies to result. In this context, the main assumptions of the mainstream theoretical approach are challenged and reevaluated, behavioral economics is one of the main challengers. Without developing in an integrated school of thought yet, behavioral economics brings new elements within the framework of economic thinking. How are the main theoretical approaches integrating these new elements and whether this process is going to narrow the theory or enrich it to be more comprehensive are questions to which this paper tries to answer, or, at least, to leave room for an answer.

  1. Theoretical and methodological approaches in discourse analysis.

    Science.gov (United States)

    Stevenson, Chris

    2004-10-01

    Discourse analysis (DA) embodies two main approaches: Foucauldian DA and radical social constructionist DA. Both are underpinned by social constructionism to a lesser or greater extent. Social constructionism has contested areas in relation to power, embodiment, and materialism, although Foucauldian DA does focus on the issue of power. Embodiment and materialism may be especially relevant for researchers of nursing where the physical body is prominent. However, the contested nature of social constructionism allows a fusion of theoretical and methodological approaches tailored to a specific research interest. In this paper, Chris Stevenson suggests a frame- work for working out and declaring the DA approach to be taken in relation to a research area, as well as to aid anticipating methodological critique. Method, validity, reliability and scholarship are discussed from within a discourse analytic frame of reference.

  2. Courcelle's Theorem - A Game-Theoretic Approach

    CERN Document Server

    Kneis, Joachim; Rossmanith, Peter

    2011-01-01

    Courcelle's Theorem states that every problem definable in Monadic Second-Order logic can be solved in linear time on structures of bounded treewidth, for example, by constructing a tree automaton that recognizes or rejects a tree decomposition of the structure. Existing, optimized software like the MONA tool can be used to build the corresponding tree automata, which for bounded treewidth are of constant size. Unfortunately, the constants involved can become extremely large - every quantifier alternation requires a power set construction for the automaton. Here, the required space can become a problem in practical applications. In this paper, we present a novel, direct approach based on model checking games, which avoids the expensive power set construction. Experiments with an implementation are promising, and we can solve problems on graphs where the automata-theoretic approach fails in practice.

  3. A decision theoretical approach for diffusion promotion

    Science.gov (United States)

    Ding, Fei; Liu, Yun

    2009-09-01

    In order to maximize cost efficiency from scarce marketing resources, marketers are facing the problem of which group of consumers to target for promotions. We propose to use a decision theoretical approach to model this strategic situation. According to one promotion model that we develop, marketers balance between probabilities of successful persuasion and the expected profits on a diffusion scale, before making their decisions. In the other promotion model, the cost for identifying influence information is considered, and marketers are allowed to ignore individual heterogeneity. We apply the proposed approach to two threshold influence models, evaluate the utility of each promotion action, and provide discussions about the best strategy. Our results show that efforts for targeting influentials or easily influenced people might be redundant under some conditions.

  4. An information theoretic approach to pedigree reconstruction.

    Science.gov (United States)

    Almudevar, Anthony

    2016-02-01

    Network structure is a dominant feature of many biological systems, both at the cellular level and within natural populations. Advances in genotype and gene expression screening made over the last few decades have permitted the reconstruction of these networks. However, resolution to a single model estimate will generally not be possible, leaving open the question of the appropriate method of formal statistical inference. The nonstandard structure of the problem precludes most traditional statistical methodologies. Alternatively, a Bayesian approach provides a natural methodology for formal inference. Construction of a posterior density on the space of network structures allows formal inference regarding features of network structure using specific marginal posterior distributions. An information theoretic approach to this problem will be described, based on the Minimum Description Length principle. This leads to a Bayesian inference model based on the information content of data rather than on more commonly used probabilistic models. The approach is applied to the problem of pedigree reconstruction based on genotypic data. Using this application, it is shown how the MDL approach is able to provide a truly objective control for model complexity. A two-cohort model is used for a simulation study. The MDL approach is compared to COLONY-2, a well known pedigree reconstruction application. The study highlights the problem of genotyping error modeling. COLONY-2 requires prior error rate estimates, and its accuracy proves to be highly sensitive to these estimates. In contrast, the MDL approach does not require prior error rate estimates, and is able to accurately adjust for genotyping error across the range of models considered. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Nanorobotics current approaches and techniques

    CERN Document Server

    Ferreira, Antoine

    2013-01-01

    Nanorobot devices now perform a wide variety of tasks at the nanoscale in a wide variety of fields including but not limited to fields such as manufacturing, medicine, supply chain, biology, and outer space. Nanorobotics: Current Approaches and Techniques is a comprehensive overview of this interdisciplinary field with a wide ranging discussion that includes nano-manipulation and industrial nanorobotics, nanorobotics in biology and medicine, nanorobotic sensing, navigation and swarm behavior, and protein and DNA-based nanorobotics. Also included is the latest on topics such as bio-nano-actuators and propulsion and navigation of nanorobotic systems using magnetic fields. Nanorobotics: Current Approaches and Techniques is an ideal book for scientists, researchers, and engineers actively involved in applied and robotic research and development.

  6. Theoretical approaches to social innovation – A critical literature review

    NARCIS (Netherlands)

    Butzin, A.; Davis, A.; Domanski, D.; Dhondt, S.; Howaldt, J.; Kaletka, C.; Kesselring, A.; Kopp, R.; Millard, J.; Oeij, P.; Rehfeld, D.; Schaper-Rinkel, P.; Schwartz, M.; Scoppetta, A.; Wagner-Luptacik, P.; Weber, M.

    2014-01-01

    The SI-DRIVE report “Theoretical approaches to Social Innovation – A Critical Literature Review” delivers a comprehensive overview on the state of the art of theoretically relevant building blocks for advancing a theoretical understanding of social innovation. It collects different theoretical

  7. Titanocene / cyclodextrin supramolecular systems: a theoretical approach

    Directory of Open Access Journals (Sweden)

    Riviş Adrian

    2012-11-01

    Full Text Available Abstract Background Recently, various metallocenes were synthesized and analyzed by biological activity point of view (such as antiproliferative properties: ruthenocenes, cobaltoceniums, titanocenes, zirconocenes, vanadocenes, niobocenes, molibdocenes etc. Two main disadvantages of metallocenes are the poor hydrosolubility and the hydrolytic instability. These problems could be resolved in two ways: synthetically modifying the structure or finding new formulations with enhanced properties. The aqueous solubility of metallocenes with cytostatic activities could be enhanced by molecular encapsulation in cyclodextrins, as well as the hydrolytic instability of these compounds could be reduced. Results This study presents a theoretical approach on the nanoencapsulation of a series of titanocenes with cytotoxic activity in α-, β-, and γ-cyclodextrin. The HyperChem 5.11 package was used for building and molecular modelling of titanocene and cyclodextrin structures, as well as for titanocene/cyclodextrin complex optimization. For titanocene/cyclodextrin complex optimization experiments, the titanocene and cyclodextrin structures in minimal energy conformations were set up at various distances and positions between molecules (molecular mechanics functionality, MM+. The best interaction between titanocene structures and cyclodextrins was obtained in the case of β- and γ-cyclodextrin, having the hydrophobic moieties oriented to the secondary face of cyclodextrin. The hydrophobicity of titanocenes (logP correlate with the titanocene-cyclodextrin interaction parameters, especially with the titanocene-cyclodextrin interaction energy; the compatible geometry and the interaction energy denote that the titanocene/β- and γ-cyclodextrin complex can be achieved. Valuable quantitative structure-activity relationships (QSARs were also obtained in the titanocene class by using the same logP as the main parameter for the in vitro cytotoxic activity against He

  8. Theoretical approaches to the diagnosis of altered states of consciousness.

    Science.gov (United States)

    Boly, Melanie; Massimini, Marcello; Tononi, Giulio

    2009-01-01

    Assessing the level of consciousness of noncommunicative brain-damaged patients is difficult, as one has to make inferences based on the patients' behavior. However, behavioral responses of brain-damaged patients are usually limited not only by their cognitive dysfunctions, but also by their frequent motor impairment. For these reasons, it is essential to resort to para-clinical markers of the level of consciousness. In recent years, a number of studies compared brain activity in comatose and vegetative state patients to that in healthy volunteers, and in other conditions of reduced consciousness such as sleep, anesthesia, or epileptic seizures. Despite the increasing amount of experimental results, no consensus on the brain mechanisms generating consciousness has yet been reached. Here, we discuss the need to combine a theoretical approach with current experimental procedures to obtain a coherent, parsimonious explanation for the loss of consciousness in several different conditions, such as coma, vegetative state, sleep, anesthesia, and epileptic seizures. In our view, without a theoretical account of how conscious experience is generated by the brain, it will remain difficult to understand the mechanisms underlying the generation of consciousness, and to predict reliably its presence or absence in noncommunicative brain-damaged patients. In this context, we review current theoretical approaches to consciousness, and how well they fit with current evidence on the neural correlates of experience. Specifically, we emphasize the principled approach provided by the Integrated Information Theory of Consciousness (IITC). We describe the different conditions where the theory predicts markedly reduced states of consciousness, and discuss several technical and conceptual issues limiting its applicability to measuring the level of consciousness of individual patients. Nevertheless, we argue that some of the predictions of the theory are potentially testable using available

  9. A theoretical approach to measuring pilot workload

    Science.gov (United States)

    Kantowitz, B. H.

    1984-01-01

    Theoretical assumptions used by researchers in the area of attention, with emphasis upon errors and inconsistent assumptions used by some researchers were studied. Two GAT experiments, two laboratory studies and one field experiment were conducted.

  10. Bruxism and Current Treatment Approaches

    Directory of Open Access Journals (Sweden)

    Selin Eren

    2016-06-01

    Full Text Available Among the mastication system disorders bruxism is a parafunctional behavior that comes from psychophysiological origin. Epidemiologic studies have reported great variability of bruxism prevalence. The factors that could cause bruxism is highly controversial. There are different opinions on this issue. The etiologic factors of bruxism include stress, malnutrition, allergic and endocrinologic diseases, central nervous system disorders, genetic factors, medicines, malocclusion, and wrong dental treatment. The aim of treatment of bruxism is to prevent damage that may occur on teeth and in the temporomandibular joint and to eliminate pain. Dental treatment, physical therapy, pharmacological treatment and behavioral and cognitive therapy can be considered for this purpose of treatment. This review summarizes the etiologic factors, epidemiology, diagnosis, and current treatment approaches of patient with bruxism. [Archives Medical Review Journal 2016; 25(2.000: 241-258

  11. Child Language Acquisition: Contrasting Theoretical Approaches

    Science.gov (United States)

    Ambridge, Ben; Lieven, Elena V. M.

    2011-01-01

    Is children's language acquisition based on innate linguistic structures or built from cognitive and communicative skills? This book summarises the major theoretical debates in all of the core domains of child language acquisition research (phonology, word-learning, inflectional morphology, syntax and binding) and includes a complete introduction…

  12. Child Language Acquisition: Contrasting Theoretical Approaches

    Science.gov (United States)

    Ambridge, Ben; Lieven, Elena V. M.

    2011-01-01

    Is children's language acquisition based on innate linguistic structures or built from cognitive and communicative skills? This book summarises the major theoretical debates in all of the core domains of child language acquisition research (phonology, word-learning, inflectional morphology, syntax and binding) and includes a complete introduction…

  13. [Current Approaches in Cancer Immunotherapy].

    Science.gov (United States)

    Otáhal, P; Trněný, M

    2015-01-01

    Methods of cancer immunotherapy have finally entered clinical medicine after years of preclinical research. Currently, there are several methods, which have proven to be very effective even in cases of incurable cancer. Antitumor monoclonal antibodies are among major therapeutic anti-cancer drugs and have been successfully used for many ears. Novel group of antibodies are immunomodulatory antibodies which can break tumor -specific immune tolerance and induce regression of tumors by nonspecific activation of immune system. Bispecific antibodies represent a novel class of anticancer agents which can induce expansion of T cells in vivo, blinatumomab is an example of such agents and is currently available for the treatment of acute B -cell leukemia. Cellular immunotherapy is also very effective, especially the use of Chimeric receptor modified T-cells for the therapy of B- cell lymphoproliferative diseases. Although it is a very complicated and expensive method, it is highly effective approach which can induce remission even in previously hopeless conditions. The goal of this article is to explain the basic principles of cancer immunotherapy and summarize the newest findings in this field.

  14. Theoretical Approach to Electroresistance in Ferroelectric Tunnel Junctions

    Science.gov (United States)

    Chang, Sou-Chi; Naeemi, Azad; Nikonov, Dmitri E.; Gruverman, Alexei

    2017-02-01

    In this paper, a theoretical approach comprising the nonequilibrium Green's function method for electronic transport and the Landau-Khalatnikov equation for electric polarization dynamics is presented to describe polarization-dependent tunneling electroresistance (TER) in ferroelectric tunnel junctions. Using appropriate contact, interface, and ferroelectric parameters, the measured current-voltage characteristic curves in both inorganic (Co /BaTi O3/La0.67Sr0.33 MnO3 ) and organic (Au /PVDF /W ) ferroelectric tunnel junctions can be well described by the proposed approach. Furthermore, under this theoretical framework, the controversy of opposite TER signs observed experimentally by different groups in Co /BaTi O3/La0.67Sr0.33 MnO3 systems is addressed by considering the interface termination effects using the effective contact ratio defined through the effective screening length and dielectric response at the metal-ferroelectric interfaces. Finally, our approach is extended to investigate the role of a CoOx buffer layer at the Co /BaTi O3 interface in a ferroelectric tunnel memristor. It is shown that in order to have a significant memristor behavior not only the interface oxygen vacancies but also the CoOx layer thickness may vary with the applied bias.

  15. System-theoretic approach to image interest point detection

    CERN Document Server

    Pimenov, Vitaly

    2010-01-01

    Interest point detection is a common task in various computer vision applications. Although a big variety of detector are developed so far computational efficiency of interest point based image analysis remains to be the problem. Current paper proposes a system-theoretic approach to interest point detection. Starting from the analysis of interdependency between detector and descriptor it is shown that given a descriptor it is possible to introduce to notion of detector redundancy. Furthermore for each detector it is possible to construct its irredundant and equivalent modification. Modified detector possesses lower computational complexity and is preferable. It is also shown that several known approaches to reduce computational complexity of image registration can be generalized in terms of proposed theory.

  16. Theoretical approaches to lightness and perception.

    Science.gov (United States)

    Gilchrist, Alan

    2015-01-01

    Theories of lightness, like theories of perception in general, can be categorized as high-level, low-level, and mid-level. However, I will argue that in practice there are only two categories: one-stage mid-level theories, and two-stage low-high theories. Low-level theories usually include a high-level component and high-level theories include a low-level component, the distinction being mainly one of emphasis. Two-stage theories are the modern incarnation of the persistent sensation/perception dichotomy according to which an early experience of raw sensations, faithful to the proximal stimulus, is followed by a process of cognitive interpretation, typically based on past experience. Like phlogiston or the ether, raw sensations seem like they must exist, but there is no clear evidence for them. Proximal stimulus matches are postperceptual, not read off an early sensory stage. Visual angle matches are achieved by a cognitive process of flattening the visual world. Likewise, brightness (luminance) matches depend on a cognitive process of flattening the illumination. Brightness is not the input to lightness; brightness is slower than lightness. Evidence for an early (perception, the many claims tend to fall apart upon close inspection of the evidence. Much of the evidence for the current revival of the 'new look' is probably better explained by (1) a natural desire of (some) subjects to please the experimenter, and (2) the ease of intuiting an experimental hypothesis. High-level theories of lightness are overkill. The visual system does not need to know the amount of illumination, merely which surfaces share the same illumination. This leaves mid-level theories derived from the gestalt school. Here the debate seems to revolve around layer models and framework models. Layer models fit our visual experience of a pattern of illumination projected onto a pattern of reflectance, while framework models provide a better account of illusions and failures of constancy

  17. Current clinical approach to achalasia

    Institute of Scientific and Technical Information of China (English)

    Alexander J Eckardt; Volker F Eckardt

    2009-01-01

    Idiopathic achalasia is a rare primary motility disorder of the esophagus.The classical features are incomplete relaxation of a frequently hypertensive lower esophageal sphincter (LES) and a lack of peristalsis in the tubular esophagus.These motor abnormalities lead to dysphagia,stasis,regurgitation,weight loss,or secondary respiratory complications.Although major strides have been made in understanding the pathogenesis of this rare disorder,including a probable autoimmune mediated destruction of inhibitory neurons in response to an unknown insult in genetically susceptible individuals,a definite trigger has not been identified.The diagnosis of achalasia is suggested by clinical features and confirmed by further diagnostic tests,such as esophagogastroduodenoscopy (EGD),manometry or barium swallow.These studies are not only used to exclude pseudoachalasia,but also might help to categorize the disease by severity or clinical subtype.Recent advances in diagnostic methods,including high resolution manometry (HRM),might allow prediction of treatment responses.The primary treatments for achieving long-term symptom relief are surgery and endoscopic methods.Although limited high-quality data exist,it appears that laparoscopic Heller myotomy with partial fundoplication is superior to endoscopic methods in achieving long-term relief of symptoms in the majority of patients.However,the current clinical approach to achalasia will depend not only on patients' characteristics and clinical subtypes of the disease,but also on local expertise and patient preferences.

  18. Theoretical, Methodological, and Empirical Approaches to Cost Savings: A Compendium

    Energy Technology Data Exchange (ETDEWEB)

    M Weimar

    1998-12-10

    This publication summarizes and contains the original documentation for understanding why the U.S. Department of Energy's (DOE's) privatization approach provides cost savings and the different approaches that could be used in calculating cost savings for the Tank Waste Remediation System (TWRS) Phase I contract. The initial section summarizes the approaches in the different papers. The appendices are the individual source papers which have been reviewed by individuals outside of the Pacific Northwest National Laboratory and the TWRS Program. Appendix A provides a theoretical basis for and estimate of the level of savings that can be" obtained from a fixed-priced contract with performance risk maintained by the contractor. Appendix B provides the methodology for determining cost savings when comparing a fixed-priced contractor with a Management and Operations (M&O) contractor (cost-plus contractor). Appendix C summarizes the economic model used to calculate cost savings and provides hypothetical output from preliminary calculations. Appendix D provides the summary of the approach for the DOE-Richland Operations Office (RL) estimate of the M&O contractor to perform the same work as BNFL Inc. Appendix E contains information on cost growth and per metric ton of glass costs for high-level waste at two other DOE sites, West Valley and Savannah River. Appendix F addresses a risk allocation analysis of the BNFL proposal that indicates,that the current approach is still better than the alternative.

  19. THEORETICAL APPROACHES DEFINE SENSE OF INVESTMENT PROJECT

    OpenAIRE

    Yu. A. Burduzha

    2010-01-01

    The essence of terms “project”, “investment project” is defined in the article, as well as the difference between definitions of terms “project”, “plan” and “program” is determined. The main approaches to the treatment of definition of term “investment project” are considered.

  20. Partial discharge transients: The field theoretical approach

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson; Crichton, George C

    1998-01-01

    Up until the mid-1980s the theory of partial discharge transients was essentially static. This situation had arisen because of the fixation with the concept of void capacitance and the use of circuit theory to address what is in essence a field problem. Pedersen rejected this approach and instead...

  1. THEORETICAL APPROACHES DEFINE SENSE OF INVESTMENT PROJECT

    Directory of Open Access Journals (Sweden)

    Yu. A. Burduzha

    2010-11-01

    Full Text Available The essence of terms “project”, “investment project” is defined in the article, as well as the difference between definitions of terms “project”, “plan” and “program” is determined. The main approaches to the treatment of definition of term “investment project” are considered.

  2. Understanding bimolecular machines: Theoretical and experimental approaches

    Science.gov (United States)

    Goler, Adam Scott

    This dissertation concerns the study of two classes of molecular machines from a physical perspective: enzymes and membrane proteins. Though the functions of these classes of proteins are different, they each represent important test-beds from which new understanding can be developed by the application of different techniques. HIV1 Reverse Transcriptase is an enzyme that performs multiple functions, including reverse transcription of RNA into an RNA/DNA duplex, RNA degradation by the RNaseH domain, and synthesis of dsDNA. These functions allow for the incorporation of the retroviral genes into the host genome. Its catalytic cycle requires repeated large-scale conformational changes fundamental to its mechanism. Motivated by experimental work, these motions were studied theoretically by the application of normal mode analysis. It was observed that the lowest order modes correlate with largest amplitude (low-frequency) motion, which are most likely to be catalytically relevant. Comparisons between normal modes obtained via an elastic network model to those calculated from the essential dynamics of a series of all-atom molecular dynamics simulations show the self-consistency between these calculations. That similar conformational motions are seen between independent theoretical methods reinforces the importance of large-scale subdomain motion for the biochemical action of DNA polymerases in general. Moreover, it was observed that the major subunits of HIV1 Reverse Transcriptase interact quasi-harmonically. The 5HT3A Serotonin receptor and P2X1 receptor, by contrast, are trans-membrane proteins that function as ligand gated ion channels. Such proteins feature a central pore, which allows for the transit of ions necessary for cellular function across a membrane. The pore is opened by the ligation of binding sites on the extracellular portion of different protein subunits. In an attempt to resolve the individual subunits of these membrane proteins beyond the diffraction

  3. Unification of theoretical approaches for epidemic spreading on complex networks

    Science.gov (United States)

    Wang, Wei; Tang, Ming; Stanley, H. Eugene; Braunstein, Lidia A.

    2017-03-01

    Models of epidemic spreading on complex networks have attracted great attention among researchers in physics, mathematics, and epidemiology due to their success in predicting and controlling scenarios of epidemic spreading in real-world scenarios. To understand the interplay between epidemic spreading and the topology of a contact network, several outstanding theoretical approaches have been developed. An accurate theoretical approach describing the spreading dynamics must take both the network topology and dynamical correlations into consideration at the expense of increasing the complexity of the equations. In this short survey we unify the most widely used theoretical approaches for epidemic spreading on complex networks in terms of increasing complexity, including the mean-field, the heterogeneous mean-field, the quench mean-field, dynamical message-passing, link percolation, and pairwise approximation. We build connections among these approaches to provide new insights into developing an accurate theoretical approach to spreading dynamics on complex networks.

  4. A Field Theoretic Approach to Roughness Corrections

    CERN Document Server

    Wu, Hua Yao

    2011-01-01

    We develop a systematic field theoretic description for the roughness correction to the Casimir free energy of parallel plates. Roughness is modeled by specifying a generating functional for correlation functions of the height profile, the two-point correlation function being characterized by the variance, \\sigma^2, and correlation length, \\ell, of the profile. We obtain the partition function of a massless scalar quantum field interacting with the height profile of the surface via a \\delta-function potential. The partition function of this model is also given by a holographic reduction to three coupled scalar fields on a two-dimensional plane. The original three-dimensional space with a parallel plate at separation 'a' is encoded in the non-local propagators of the surface fields on its boundary. Feynman rules for this equivalent 2+1-dimensional model are derived and its counter terms constructed. The two-loop contribution to the free energy of this model gives the leading roughness correction. The absolute ...

  5. THE NETWORKS IN TOURISM: A THEORETICAL APPROACH

    Directory of Open Access Journals (Sweden)

    Maria TĂTĂRUȘANU

    2016-12-01

    Full Text Available The economic world in which tourism companies act today is in a continuous changing process. The most important factor of these changes is the globalization of their environment, both in economic, social, natural and cultural aspects. The tourism companies can benefit from the opportunities brought by globalization, but also could be menaced by the new context. How could react the companies to these changes in order to create and maintain long term competitive advantage for their business? In the present paper we make a literature review of the new tourism companies´ business approach: the networks - a result and/or a reason for exploiting the opportunities or, on the contrary, for keeping their actual position on the market. It’s a qualitative approach and the research methods used are analyses, synthesis, abstraction, which are considered the most appropriate to achieve the objective of the paper.

  6. A graph theoretical approach to data fusion

    Science.gov (United States)

    Žurauskienė, Justina; Kirk, Paul D.W.; Stumpf, Michael P.H.

    2016-01-01

    The rapid development of high throughput experimental techniques has resulted in a growing diversity of genomic datasets being produced and requiring analysis. Therefore, it is increasingly being recognized that we can gain deeper understanding about underlying biology by combining the insights obtained from multiple, diverse datasets. Thus we propose a novel scalable computational approach to unsupervised data fusion. Our technique exploits network representations of the data to identify similarities among the datasets. We may work within the Bayesian formalism, using Bayesian nonparametric approaches to model each dataset; or (for fast, approximate, and massive scale data fusion) can naturally switch to more heuristic modeling techniques. An advantage of the proposed approach is that each dataset can initially be modeled independently (in parallel), before applying a fast post-processing step to perform data integration. This allows us to incorporate new experimental data in an online fashion, without having to rerun all of the analysis. We first demonstrate the applicability of our tool on artificial data, and then on examples from the literature, which include yeast cell cycle, breast cancer and sporadic inclusion body myositis datasets. PMID:26992203

  7. New theoretical approaches to black holes

    CERN Document Server

    Gourgoulhon, Eric

    2008-01-01

    Quite recently, some new mathematical approaches to black holes have appeared in the literature. They do not rely on the classical concept of event horizon -- which is very global, but on the local concept of hypersurfaces foliated by trapped surfaces. After a brief introduction to these new horizons, we focus on a viscous fluid analogy that can be developed to describe their dynamics, in a fashion similar to the membrane paradigm introduced for event horizons in the seventies, but with a significant change of sign of the bulk viscosity.

  8. The dynamics of alliances : a game theoretical approach

    NARCIS (Netherlands)

    Ridder, A. de

    2007-01-01

    In this dissertation, Annelies de Ridder presents a game theoretical approach to strategic alliances. More specifically, the dynamics of and within alliances have been studied. To do so, four new models have been developed in the game theoretical tradition. Both coalition theory and strategic game t

  9. MEDICAL BRAIN DRAIN - A THEORETICAL APPROACH

    Directory of Open Access Journals (Sweden)

    Boncea Irina

    2013-07-01

    Full Text Available Medical brain drain is defined as the migration of health personnel from developing countries to developed countries and between industrialized nations in search for better opportunities. This phenomenon became a global growing concern due to its impact on both the donor and the destination countries. This article aims to present the main theoretical contributions starting from 1950 until today and the historical evolution, in the attempt of correlating the particular case of medical brain drain with the theory and evolution of the brain drain in general. This article raises questions and offers answers, identifies the main issues and looks for possible solutions in order to reduce the emigration of medical doctors. Factors of influence include push (low level of income, poor working conditions, the absence of job openings and social recognition, oppressive political climate and pull (better remuneration and working conditions, prospects for career development, job satisfaction, security factors. Developing countries are confronting with the loss of their most valuable intellectuals and the investment in their education, at the benefit of developed nations. An ethical debate arises as the disparities between countries increases, industrialized nations filling in the gaps in health systems with professionals from countries already facing shortages. However, recent literature emphasizes the possibility of a “beneficial brain drain” through education incentives offered by the emigration prospects. Other sources of “brain gain” for donor country are the remittances, the scientific networks and return migration. Measures to stem the medical brain drain involve the common effort and collaboration between developing and developed countries and international organizations. Measures adopted by donor countries include higher salaries, better working conditions, security, career opportunities, incentives to stimulate return migration. Destination

  10. Management and human values in Nigeria: A theoretical approach ...

    African Journals Online (AJOL)

    Management and human values in Nigeria: A theoretical approach. ... evolving ethical and human value-based practices as a form of competitive advantage ... has consistently shifted towards value-based models of growth in the workplace.

  11. Islamic Theoretical Intertemporal Model of the Current Account

    Directory of Open Access Journals (Sweden)

    Hassan Belkacem Ghassan

    2016-06-01

    Full Text Available This paper aims to develop an Islamic intertemporal model of the current account based on the prevailing theoretical and empirical literature of PVMCA (Obstfeld and Rogoff, 1996, Cerrato et al., 2014. The proposed model is based on the budget constraint of the present and future consumption, which depends on the obligatory Zakat from the income and assets, the return rate on the owned assets, the inheritance linking previous to subsequent generation. Using logarithmic utility function, featured by a unitary elasticity of intertemporal substitution and a unitary coefficient of relative risk aversion, we show through Euler equation of consumption that there is an inverse relationship between consumption growth from the last age to the first one and the Zakat rate on assets. The outcomes of this result are that the Zakat on assets disciplines the consumer to have more rationality in consumption, and allows additional marginal assets for future generations. By assuming a unitary subjective discount rate, we indicate that the more the return rate on assets is high, the more the consumption growth between today and tomorrow will be fast. Through the budget constraint, if Zakat rate on the Zakatable assets is greater than Zakat rate on income, this leads to a relative expansion in private consumption of the wealthy group. Besides, we point out that an increase in return rate on assets, can drive to increasing or decreasing current consumption, because the substitution and income effects work in opposite ways.

  12. Social representations: a theoretical approach in health

    Directory of Open Access Journals (Sweden)

    Isaiane Santos Bittencourt

    2011-03-01

    Full Text Available Objective: To present the theory of social representations, placing its epistemology and knowing the basic concepts of its approach as a structural unit of knowledge for health studies. Justification: The use of this theory comes from the need to understand social eventsunder the lens of the meanings constructed by the community. Data Synthesis: This was a descriptive study of literature review, which used as a source of data collection the classical authors of social representations supported by articles from electronic search at Virtual Health Library (VHL. The definition and discussion of collected data enabled to introduce two themes, versed on the history and epistemology of representations and on the structuralapproach of representations in health studies. Conclusion: This review allowed highlight the importance of locating the objects of study with regard to contextual issues of individual and collective histories, valuing the plurality of relations, to come closer to reality that is represented by the subjects.

  13. A graph theoretic approach to graded identities

    CERN Document Server

    Haile, Darrell

    2011-01-01

    We consider the algebra M_k(C) of k-by-k matrices over the complex numbers and view it as a crossed product with a group G of order k by embedding G in the symmetric group S_k via the regular representation and embedding S_k in M_k(C) in the usual way. This induces a natural G-grading on M_k(C) which we call a crossed product grading. This grading is the so called elementary grading defined by any k-tuple (g_1,g_2,..., g_k) of distinct elements g_i in G. We study the graded polynomial identities for M_k(C) equipped with a crossed product grading. To each multilinear monomial in the free graded algebra we associate a directed labeled graph. This approach allows us to give new proofs of known results of Bahturin and Drensky on the generators of the T-ideal of identities and the Amitsur-Levitsky Theorem. Our most substantial new result is the determination of the asymptotic formula for the G-graded codimension of M_k(C).

  14. Reconciling current approaches to blindsight

    DEFF Research Database (Denmark)

    Overgaard, Morten; Mogensen, Jesper

    2015-01-01

    After decades of research, blindsight is still a mysterious and controversial topic in consciousness research. Currently, many researchers tend to think of it as an ideal phenomenon to investigate neural correlates of consciousness, whereas others believe that blindsight is in fact a kind...

  15. Reconciling current approaches to blindsight

    DEFF Research Database (Denmark)

    Overgaard, Morten; Mogensen, Jesper

    2015-01-01

    After decades of research, blindsight is still a mysterious and controversial topic in consciousness research. Currently, many researchers tend to think of it as an ideal phenomenon to investigate neural correlates of consciousness, whereas others believe that blindsight is in fact a kind...

  16. Preservation of Newspapers: Theoretical Approaches and Practical Achievements

    Science.gov (United States)

    Hasenay, Damir; Krtalic, Maja

    2010-01-01

    The preservation of newspapers is the main topic of this paper. A theoretical overview of newspaper preservation is given, with an emphasis on the importance of a systematic and comprehensive approach. Efficient newspaper preservation implies understanding the meaning of preservation in general, as well as understanding specific approaches,…

  17. Dramaturgical and Music-Theoretical Approaches to Improvisation Pedagogy

    Science.gov (United States)

    Huovinen, Erkki; Tenkanen, Atte; Kuusinen, Vesa-Pekka

    2011-01-01

    The aim of this article is to assess the relative merits of two approaches to teaching musical improvisation: a music-theoretical approach, focusing on chords and scales, and a "dramaturgical" one, emphasizing questions of balance, variation and tension. Adult students of music pedagogy, with limited previous experience in improvisation,…

  18. Postmodern Implications for Theoretical Integration of Counseling Approaches.

    Science.gov (United States)

    Hansen, James T.

    2002-01-01

    Theoretical integration refers to the conceptual unification of diverse counseling approaches. Contends that the general failure of integrative attempts is a by-product of the modernistic epistemic context in which the systems were considered and proposes an examination of common narrative features of counseling approaches in a postmodern…

  19. Carious dentine removal: current approach

    Directory of Open Access Journals (Sweden)

    Germana Coeli de Farias Sales

    2008-01-01

    Full Text Available Dentistry is renewed day after day through the results of qualified researches. The approach as regards carious dentin removal is goingthrough questioning and innovation. The scope of this study was to perform a literature review in the sense of elucidating questions pertaining to the problem of whether or not it is necessary to completely remove carious dentin, and the possibility of performing restoration in a single session, in addition to a discussion about which type of material should be applied in this type of substrate. After analyzing the referenced articles, it was concluded that the stepwise treatment controls caries progression; there is a trend in the literature to partially remove the carious dentin in deep lesions and perform definitive restoration; Calcium hydroxide cement is a classical liner in these situations, while glass ionomer cement and resinous materials are other possibilities of materials that can be in close contact with the remaining dentin.

  20. A perturbation-theoretic approach to Lagrangian flow networks

    Science.gov (United States)

    Fujiwara, Naoya; Kirchen, Kathrin; Donges, Jonathan F.; Donner, Reik V.

    2017-03-01

    Complex network approaches have been successfully applied for studying transport processes in complex systems ranging from road, railway, or airline infrastructures over industrial manufacturing to fluid dynamics. Here, we utilize a generic framework for describing the dynamics of geophysical flows such as ocean currents or atmospheric wind fields in terms of Lagrangian flow networks. In this approach, information on the passive advection of particles is transformed into a Markov chain based on transition probabilities of particles between the volume elements of a given partition of space for a fixed time step. We employ perturbation-theoretic methods to investigate the effects of modifications of transport processes in the underlying flow for three different problem classes: efficient absorption (corresponding to particle trapping or leaking), constant input of particles (with additional source terms modeling, e.g., localized contamination), and shifts of the steady state under probability mass conservation (as arising if the background flow is perturbed itself). Our results demonstrate that in all three cases, changes to the steady state solution can be analytically expressed in terms of the eigensystem of the unperturbed flow and the perturbation itself. These results are potentially relevant for developing more efficient strategies for coping with contaminations of fluid or gaseous media such as ocean and atmosphere by oil spills, radioactive substances, non-reactive chemicals, or volcanic aerosols.

  1. One-dimensional barcode reading: an information theoretic approach.

    Science.gov (United States)

    Houni, Karim; Sawaya, Wadih; Delignon, Yves

    2008-03-10

    In the convergence context of identification technology and information-data transmission, the barcode found its place as the simplest and the most pervasive solution for new uses, especially within mobile commerce, bringing youth to this long-lived technology. From a communication theory point of view, a barcode is a singular coding based on a graphical representation of the information to be transmitted. We present an information theoretic approach for 1D image-based barcode reading analysis. With a barcode facing the camera, distortions and acquisition are modeled as a communication channel. The performance of the system is evaluated by means of the average mutual information quantity. On the basis of this theoretical criterion for a reliable transmission, we introduce two new measures: the theoretical depth of field and the theoretical resolution. Simulations illustrate the gain of this approach.

  2. [Resource activation in clinical psychology and psychotherapy: review of theoretical issues and current research].

    Science.gov (United States)

    Groß, L J; Stemmler, M; de Zwaan, M

    2012-08-01

    This review summarises theoretical issues and current research on working with clients' resources and strengths in clinical psychology and psychotherapy. Resource activation is considered as an important common factor in psychotherapy. In general, resource activation means an explicit focus on resources, strengths and potentials of the clients. After defining the term resources, considerations with regard to therapeutic attitude, principles of resource activation, approaches to resource diagnostics and different research strategies are presented. Current research focuses especially on the relation between resource activation and process variables in out-patient treatment.

  3. A Field-Theoretic Approach to the Wiener Sausage

    Science.gov (United States)

    Nekovar, S.; Pruessner, G.

    2016-05-01

    The Wiener Sausage, the volume traced out by a sphere attached to a Brownian particle, is a classical problem in statistics and mathematical physics. Initially motivated by a range of field-theoretic, technical questions, we present a single loop renormalised perturbation theory of a stochastic process closely related to the Wiener Sausage, which, however, proves to be exact for the exponents and some amplitudes. The field-theoretic approach is particularly elegant and very enjoyable to see at work on such a classic problem. While we recover a number of known, classical results, the field-theoretic techniques deployed provide a particularly versatile framework, which allows easy calculation with different boundary conditions even of higher momenta and more complicated correlation functions. At the same time, we provide a highly instructive, non-trivial example for some of the technical particularities of the field-theoretic description of stochastic processes, such as excluded volume, lack of translational invariance and immobile particles. The aim of the present work is not to improve upon the well-established results for the Wiener Sausage, but to provide a field-theoretic approach to it, in order to gain a better understanding of the field-theoretic obstacles to overcome.

  4. A System Theoretical Inspired Approach to Knowledge Construction

    DEFF Research Database (Denmark)

    Mathiasen, Helle

    2008-01-01

    student's knowledge construction, in the light of operative constructivism, inspired by the German sociologist N. Luhmann's system theoretical approach to epistemology. Taking observations as operations based on distinction and indication (selection) contingency becomes a fundamental condition in learning....... In the light of operative constructivism this is a paradox and a challenge for the Educational system....

  5. Theoretical approaches to the glass transition in simple liquids

    Indian Academy of Sciences (India)

    Chandan Dasgupta

    2005-05-01

    Theoretical approaches to the development of an understanding of the behaviour of simple supercooled liquids near the structural glass transition are reviewed and our work on this problem, based on the density functional theory of freezing and replicated liquid state theory, are summarized in this context. A few directions for further work on this problem are suggested.

  6. Tourism Competitiveness and Destination Branding - A Theoretical Approach

    OpenAIRE

    Morar Doriana; Cotîrlea Denisa Adriana

    2012-01-01

    The present article was written in order to provide an overview of the theoretical approaches considering competitiveness and differentiation in tourism industry. Also, it emphasizes the importance of competitive advantages in destination branding, their connection and their influence on the size of tourist flows in different destinations.

  7. Scientific-theoretical research approach to practical theology in ...

    African Journals Online (AJOL)

    2017-08-18

    Aug 18, 2017 ... In this article, I present a critical literature study of the theoretical approach of practical theologians in South ... practical theological realism connects science and wisdom in a fruitful .... of church members of the violence and hurt that people experience ..... unmarried women, divorced women, homosexuals,.

  8. Theoretical Approach to Gender Differences in Conversational Style

    Institute of Scientific and Technical Information of China (English)

    Zhou Ying

    2014-01-01

    This paper points out the negative aspects of the male dominance hypothesis which is the framework of the prior research on sex differences.Proceeding from the theoretical bases of sociolinguistics,this paper attempts to propose a communicative approach by which gender differences in conversational style can be investigated completely.

  9. Theoretical approaches to low energy $\\bar{K}N$ interactions

    CERN Document Server

    Cieply, Ales

    2016-01-01

    We provide a direct comparison of modern theoretical approaches based on the SU(3) chiral dynamics and describing the low energy $\\bar{K}N$ data. The model predictions for the $\\bar{K}N$ amplitudes and pole content of the models are discussed.

  10. Neutrino interactions: challenges in the current theoretical picture

    CERN Document Server

    Alvarez-Ruso, Luis

    2010-01-01

    The present theoretical status of neutrino interactions in the few-GeV region is reviewed. Quasielastic scattering, pion production, photon emission and their importance for neutrino oscillation studies are discussed, making emphasis on the open questions that arise in the comparison with new experimental data.

  11. Neutrino interactions: Challenges in the current theoretical picture

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Ruso, Luis [Centro de Fisica Computacional, Departamento de Fisica, Universidade de Coimbra (Portugal)

    2012-08-15

    The present theoretical status of neutrino interactions in the few-GeV region is reviewed. Quasielastic scattering, pion production, photon emission and their importance for neutrino oscillation studies are discussed, making emphasis on the open questions that arise in the comparison with new experimental data.

  12. A queer-theoretical approach to community health psychology.

    Science.gov (United States)

    Easpaig, Bróna R Nic Giolla; Fryer, David M; Linn, Seònaid E; Humphrey, Rhianna H

    2014-01-01

    Queer-theoretical resources offer ways of productively rethinking how central concepts such as 'person-context', 'identity' and 'difference' may be understood for community health psychologists. This would require going beyond consideration of the problems with which queer theory is popularly associated to cautiously engage with the aspects of this work relevant to the promotion of collective practice and engaging with processes of marginalisation. In this article, we will draw upon and illustrate the queer-theoretical concepts of 'performativity' and 'cultural intelligibility' before moving towards a preliminary mapping of what a queer-informed approach to community health psychology might involve.

  13. A theoretical and methodological approach of leadership in organizations

    Directory of Open Access Journals (Sweden)

    María Laura Lupano Perugini

    2015-09-01

    Full Text Available The present work has the objective to offer a theoretical-methodological approximation respect of the leadership’s phenomenon. By virtue of the fact that such phenomenon is understood as a complex and multiderminated construct, we will approach the different theoretical schools which have tried to explain it. Also, it is attempted to answer the question about the possibility to evaluate the mentioned construct. To answer this interrogation we will present the different methodologies employed in scientific research and their possible advantages and limitations of their application to the leadership’s evaluation. 

  14. Theoretical studies of non inductive current drive in compact toroids

    NARCIS (Netherlands)

    Farengo, R; Lifschitz, AF; Caputi, KI; Arista, NR; Clemente, RA

    2002-01-01

    Three non inductive current drive methods that can be applied to compact toroids axe studied. The use of neutral beams to drive current in field reversed configurations and spheromaks is studied using a Monte Carlo code that includes a complete ionization package and follows the exact particle orbit

  15. Current Density Imaging through Acoustically Encoded Magnetometry: A Theoretical Exploration

    CERN Document Server

    Sheltraw, Daniel J

    2014-01-01

    The problem of determining a current density confined to a volume from measurements of the magnetic field it produces exterior to that volume is known to have non-unique solutions. To uniquely determine the current density, or the non-silent components of it, additional spatial encoding of the electric current is needed. In biological systems such as the brain and heart, which generate electric current associated with normal function, a reliable means of generating such additional encoding, on a spatial and temporal scale meaningful to the study of such systems, would be a boon for research. This paper explores a speculative method by which the required additional encoding might be accomplished, on the time scale associated with the propagation of sound across the volume of interest, by means of the application of a radially encoding pulsed acoustic spherical wave.

  16. A theoretical approach to artificial intelligence systems in medicine.

    Science.gov (United States)

    Spyropoulos, B; Papagounos, G

    1995-10-01

    The various theoretical models of disease, the nosology which is accepted by the medical community and the prevalent logic of diagnosis determine both the medical approach as well as the development of the relevant technology including the structure and function of the A.I. systems involved. A.I. systems in medicine, in addition to the specific parameters which enable them to reach a diagnostic and/or therapeutic proposal, entail implicitly theoretical assumptions and socio-cultural attitudes which prejudice the orientation and the final outcome of the procedure. The various models -causal, probabilistic, case-based etc. -are critically examined and their ethical and methodological limitations are brought to light. The lack of a self-consistent theoretical framework in medicine, the multi-faceted character of the human organism as well as the non-explicit nature of the theoretical assumptions involved in A.I. systems restrict them to the role of decision supporting "instruments" rather than regarding them as decision making "devices". This supporting role and, especially, the important function which A.I. systems should have in the structure, the methods and the content of medical education underscore the need of further research in the theoretical aspects and the actual development of such systems.

  17. Model selection and inference a practical information-theoretic approach

    CERN Document Server

    Burnham, Kenneth P

    1998-01-01

    This book is unique in that it covers the philosophy of model-based data analysis and an omnibus strategy for the analysis of empirical data The book introduces information theoretic approaches and focuses critical attention on a priori modeling and the selection of a good approximating model that best represents the inference supported by the data Kullback-Leibler information represents a fundamental quantity in science and is Hirotugu Akaike's basis for model selection The maximized log-likelihood function can be bias-corrected to provide an estimate of expected, relative Kullback-Leibler information This leads to Akaike's Information Criterion (AIC) and various extensions and these are relatively simple and easy to use in practice, but little taught in statistics classes and far less understood in the applied sciences than should be the case The information theoretic approaches provide a unified and rigorous theory, an extension of likelihood theory, an important application of information theory, and are ...

  18. A Theoretical Approach for Estimating Fracture Toughness of Ductile Metals

    Institute of Scientific and Technical Information of China (English)

    Y.T. He; F. Li; G.Q. Zhang; L.J. Ernst; X.J. FU

    2004-01-01

    Fracture toughness is very important when applying Damage Tolerance Design and Assessment Techniques. The traditional testing approach for obtaining fracture toughness values is costly and time consuming. In order to estimate the fracture toughness of ductile metals, the fracture mechanics theory, materials plastic deformation theory and materials constructive relationships are employed here. A series of formulae and a theoretical approach are presented to calculate fracture toughness values of different materials in the plane stress and plane strain conditions. Compared with test results, evaluated values have a good agreement.

  19. An attempt of classification of theoretical approaches to national identity

    Directory of Open Access Journals (Sweden)

    Milošević-Đorđević Jasna S.

    2003-01-01

    Full Text Available It is compulsory that complex social concepts should be defined in different ways and approached from the perspective of different science disciplines. Therefore, it is difficult to precisely define them without overlapping of meaning with other similar concepts. This paper has made an attempt towards theoretical classification of the national identity and differentiate that concept in comparison to the other related concepts (race, ethnic group, nation, national background, authoritativeness, patriarchy. Theoretical assessments are classified into two groups: ones that are dealing with nature of national identity and others that are stating one or more dimensions of national identity, crucial for its determination. On the contrary to the primordialistic concept of national identity, describing it as a fundamental, deeply rooted human feature, there are many numerous contemporary theoretical approaches (instrumentalist, constructivist, functionalistic, emphasizing changeable, fluid, instrumentalist function of the national identity. Fundamental determinants of national identity are: language, culture (music, traditional myths, state symbols (territory, citizenship, self-categorization, religion, set of personal characteristics and values.

  20. Information Ergonomics A theoretical approach and practical experience in transportation

    CERN Document Server

    Sandl, Peter

    2012-01-01

    The variety and increasing availability of hypermedia information systems, which are used in stationary applications like operators’ consoles as well as mobile systems, e.g. driver information and navigation systems in automobiles form a foundation for the mediatization of the society. From the human engineering point of view this development and the ensuing increased importance of information systems for economic and private needs require careful deliberation of the derivation and application of ergonomics methods particularly in the field of information systems. This book consists of two closely intertwined parts. The first, theoretical part defines the concept of an information system, followed by an explanation of action regulation as well as cognitive theories to describe man information system interaction. A comprehensive description of information ergonomics concludes the theoretical approach. In the second, practically oriented part of this book authors from industry as well as from academic institu...

  1. Theoretical Modeling of Internal Hydraulic Jump in Density Currents

    CERN Document Server

    Firoozabadi, Bahar; Aryanfar, Asghar; Afshin, Hossein

    2013-01-01

    In this paper, we propose an analytical framework for internal hydraulic jumps. Density jumps or internal hydraulic jumps occur when a supper critical flow of water discharges into a stagnant layer of water with slightly different density. The approach used here is control volume method which is also used to analyze ordinary hydraulic jumps. The important difference here is that entrainment is taken into account. Using conservation equations with the aid of some simplifying assumptions we come to an equation that gives jump downstream height as function of jump upstream characteristics and the entrainment. To determine the magnitude of downstream height we use an experimental equation for calculating the entrainment. Finally we verify our framework by comparing the height that we gain from the derived equation with some experimental data.

  2. Understanding employee motivation and organizational performance: Arguments for a set-theoretic approach

    Directory of Open Access Journals (Sweden)

    Michael T. Lee

    2016-09-01

    Full Text Available Empirical evidence demonstrates that motivated employees mean better organizational performance. The objective of this conceptual paper is to articulate the progress that has been made in understanding employee motivation and organizational performance, and to suggest how the theory concerning employee motivation and organizational performance may be advanced. We acknowledge the existing limitations of theory development and suggest an alternative research approach. Current motivation theory development is based on conventional quantitative analysis (e.g., multiple regression analysis, structural equation modeling. Since researchers are interested in context and understanding of this social phenomena holistically, they think in terms of combinations and configurations of a set of pertinent variables. We suggest that researchers take a set-theoretic approach to complement existing conventional quantitative analysis. To advance current thinking, we propose a set-theoretic approach to leverage employee motivation for organizational performance.

  3. SOCIOLOGICAL UNDERSTANDING OF INTERNET: THEORETICAL APPROACHES TO THE NETWORK ANALYSIS

    Directory of Open Access Journals (Sweden)

    D. E. Dobrinskaya

    2016-01-01

    Full Text Available Internet studies are carried out by various scientific disciplines and in different research perspectives. Sociological studies of the Internet deal with a new technology, a revolutionary means of mass communication and a social space. There is a set of research difficulties associated with the Internet. Firstly, the high speed and wide spread of Internet technologies’ development. Secondly, the collection and filtration of materials concerning with Internet studies. Lastly, the development of new conceptual categories, which are able to reflect the impact of the Internet development in contemporary world. In that regard the question of the “network” category use is essential. Network is the base of Internet functioning, on the one hand. On the other hand, network is the ground for almost all social interactions in modern society. So such society is called network society. Three theoretical network approaches in the Internet research case are the most relevant: network society theory, social network analysis and actor-network theory. Each of these theoretical approaches contributes to the study of the Internet. They shape various images of interactions between human beings in their entity and dynamics. All these approaches also provide information about the nature of these interactions. 

  4. Success Determination by Innovation: A Theoretical Approach in Marketing

    Directory of Open Access Journals (Sweden)

    Raj Kumar Gautam

    2012-10-01

    Full Text Available The paper aims at to identify the main issues in the marketing which needs immediate attention of the marketers. The importance of innovation in the marketing has also been highlighted and marketing mix have been related to innovative and creative ideas. The study is based on the secondary data, various research papers, articles has been studied to develop a innovative approach in the marketing. Marketing innovative ideas relating to business lead generation, product, price, distribution, promotion of product, and revenue generation have been highlighted in the paper. All the suggestions are theoretical and may have relevance and implication to the marketers.

  5. Considering children and health literacy: a theoretical approach.

    Science.gov (United States)

    Borzekowski, Dina L G

    2009-11-01

    The theoretical approaches of Paulo Freire, Jean Piaget, and Lev Vygotsky frame the consideration of children and health literacy. This article includes a general discussion of literacy from the Freirian perspective. A definition of health literacy is then presented; first, the established meaning is introduced, but then a Freirian extension is proposed. Next, the theories of cognitive development by Piaget and Vygotsky are discussed, and examples related to children's health literacy are given. Finally, there is a discussion of why it is important to encourage and enable health literacy among children and adolescents.

  6. The Knowability Argument and the Syntactic Type-Theoretic Approach

    Directory of Open Access Journals (Sweden)

    Lucas Rosenblatt

    2014-06-01

    Full Text Available Some attempts have been made to block the Knowability Paradox and other modal paradoxes by adopting a type-theoretic framework in which knowledge and necessity are regarded as typed predicates. The main problem with this approach is that when these notions are simultaneously treated as predicates, a new kind of paradox appears. I claim that avoiding this paradox either by weakening the Knowability Principle or by introducing types for both predicates is rather messy and unattractive. I also consider the prospect of using the truth predicate to emulate other modal notions. It turns out that this idea works quite well.

  7. Success Determination by Innovation: A Theoretical Approach in Marketing

    Directory of Open Access Journals (Sweden)

    Raj Kumar Gautam

    2012-11-01

    Full Text Available The paper aims at to identify the main issues in the marketing which needs immediate attention of the marketers. The importance of innovation in the marketing has also been highlighted and marketing mix have been related to innovative and creative ideas. The study is based on the secondary data, various research papers, articles has been studied to develop a innovative approach in the marketing. Marketing innovative ideas relating to business lead generation, product, price, distribution, promotion of product, and revenue generation have been highlighted in the paper. All the suggestions are theoretical and may have relevance and implication to the marketers.

  8. Exploring a type-theoretic approach to accessibility constraint modelling

    CERN Document Server

    Pogodalla, Sylvain

    2008-01-01

    The type-theoretic modelling of DRT that [degroote06] proposed features continuations for the management of the context in which a clause has to be interpreted. This approach, while keeping the standard definitions of quantifier scope, translates the rules of the accessibility constraints of discourse referents inside the semantic recipes. In this paper, we deal with additional rules for these accessibility constraints. In particular in the case of discourse referents introduced by proper nouns, that negation does not block, and in the case of rhetorical relations that structure discourses. We show how this continuation-based approach applies to those accessibility constraints and how we can consider the parallel management of various principles.

  9. On kaonic deuterium. Quantum field theoretic and relativistic covariant approach

    CERN Document Server

    Ivanov, A N; Faber, M; Fuhrmann, H; Ivanova, V A; Marton, J; Troitskaya, N I; Zmeskal, J

    2004-01-01

    We study kaonic deuterium, the bound K^-d state A_{K d}. Within a quantum field theoretic and relativistic covariant approach we derive the energy level displacement of the ground state of kaonic deuterium in terms of the amplitude of K^-d scattering for arbitrary relative momenta. Near threshold our formula reduces to the well-known DGBT formula. The S-wave amplitude of K^-d scattering near threshold is defined by the resonances Lambda(1405), Sigma(1750) and a smooth elastic background, and the inelastic channels K^- d -> NY and K^- d -> NY pion, with Y = Sigma^{+/-}, Sigma^0 and Lambda^0, where the final-state interactions play an important role. The Ericson-Weise formula for the S-wave scattering length of K^-d scattering is derived. The total width of the energy level of the ground state of kaonic deuterium is estimated using the theoretical predictions of the partial widths of the two-body decays A_{Kd} -> NY and experimental data on the rates of the NY-pair production in the reactions K^-d -> NY. We obt...

  10. On kaonic hydrogen. Quantum field theoretic and relativistic covariant approach

    CERN Document Server

    Ivanov, A N; Faber, M; Marton, J; Troitskaya, N I; Zmeskal, J

    2003-01-01

    We study kaonic hydrogen, the bound K^-p state A_(Kp). Within a quantum field theoretic and relativistic covariant approach we derive the energy level displacement of the ground state of kaonic hydrogen in terms of the amplitude of K^-p scattering for arbitrary energies. The amplitude of low-energy K^-p scattering near threshold is defined by the contributions of three resonances Lambda(1405), Lambda(1800) and Sigma^0(1750) and a smooth elastic background. The amplitudes of inelastic channels of low-energy K^-p scattering fit experimental data on near threshold behaviour of the cross sections and the experimental data by the DEAR Collaboration. We use the soft-pion technique (leading order in Chiral Perturbation Theory) for the calculate of the partial width of the radiative decay of pionic hydrogen A_(pi p) -> n + gamma and the Panofsky ratio. The theoretical prediction for the Panofsky ratio agrees well with experimental data. We apply the soft-kaon technique (leading order in Chiral Perturbation Theory) to...

  11. On kaonic hydrogen. Quantum field theoretic and relativistic covariant approach

    Science.gov (United States)

    Ivanov, A. N.; Cargnelli, M.; Faber, M.; Marton, J.; Troitskaya, N. I.; Zmeskal, J.

    2004-07-01

    We study kaonic hydrogen, the bound K - p state A K p . Within a quantum field theoretic and relativistic covariant approach we derive the energy level displacement of the ground state of kaonic hydrogen in terms of the amplitude of K - p scattering for arbitrary relative momenta. The amplitude of low-energy K - p scattering near threshold is defined by the contributions of three resonances Λ(1405), Λ(1800) and Σ^0(1750) and a smooth elastic background. The amplitudes of inelastic channels of low-energy K - p scattering fit experimental data on the near-threshold behaviour of the cross-sections and the experimental data by the DEAR Collaboration. We use the soft-pion technique (leading order in Chiral Perturbation Theory) for the calculation of the partial width of the radiative decay of pionic hydrogen A_{π p} to n + γ and the Panofsky ratio. The theoretical prediction for the Panofsky ratio agrees well with experimental data. We apply the soft-kaon technique (leading order in Chiral Perturbation Theory) to the calculation of the partial widths of radiative decays of kaonic hydrogen A_{Kp} to Λ^0 + γ and A_{K p} to Σ^0 + γ. We show that the contribution of these decays to the width of the energy level of the ground state of kaonic hydrogen is less than 1%.

  12. Investigations on Actuator Dynamics through Theoretical and Finite Element Approach

    Directory of Open Access Journals (Sweden)

    Somashekhar S. Hiremath

    2010-01-01

    Full Text Available This paper gives a new approach for modeling the fluid-structure interaction of servovalve component-actuator. The analyzed valve is a precision flow control valve-jet pipe electrohydraulic servovalve. The positioning of an actuator depends upon the flow rate from control ports, in turn depends on the spool position. Theoretical investigation is made for No-load condition and Load condition for an actuator. These are used in finite element modeling of an actuator. The fluid-structure-interaction (FSI is established between the piston and the fluid cavities at the piston end. The fluid cavities were modeled with special purpose hydrostatic fluid elements while the piston is modeled with brick elements. The finite element method is used to simulate the variation of cavity pressure, cavity volume, mass flow rate, and the actuator velocity. The finite element analysis is extended to study the system's linearized response to harmonic excitation using direct solution steady-state dynamics. It was observed from the analysis that the natural frequency of the actuator depends upon the position of the piston in the cylinder. This is a close match with theoretical and simulation results. The effect of bulk modulus is also presented in the paper.

  13. The production of scientific videos: a theoretical approach

    Directory of Open Access Journals (Sweden)

    Carlos Ernesto Gavilondo Rodriguez

    2016-12-01

    Full Text Available The article presents the results of theoretical research on the production of scientific videos and its application to the teaching-learning process carried out in schools in the city of Guayaquil, Ecuador. It is located within the production line and Audiovisual Communication. Creation of scientific videos, from the Communication major with a concentration in audiovisual production and multimedia of the Salesian Polytechnic University. For the realization of the article it was necessary to use key terms that helped subsequently to data collection. used terms such as: audiovisual production, understood as the production of content for audiovisual media; the following term used audiovisual communication is recognized as the process in which there is an exchange of messages through an audible and / or visual system; and the last term we use is scientifically video, which is one that uses audiovisual resources to obtain relevant and reliable information.As part of the theoretical results a methodological proposal for the video production is presented for educational purposes. In conclusion set out, first, that from the communicative statement in recent times, current social relations, constitute a successful context of possibilities shown to education to generate meeting points between the world of the everyday and the knowledge. Another indicator validated as part of the investigation, is that teachers surveyed use the potential of the audiovisual media, and supported them, deploy alternatives for use. 

  14. Maier-Saupe nematogenic fluid: field theoretical approach

    Directory of Open Access Journals (Sweden)

    M. Holovko

    2011-09-01

    Full Text Available We adopt a field theoretical approach to study the structure and thermodynamics of a homogeneous Maier-Saupe nematogenic fluid interacting with anisotropic Yukawa potential. In the mean field approximation we retrieve the standard Maier-Saupe theory for liquid crystals. In this theory the density is expressed via the second order Legendre polynomial of molecule orientations. In the Gaussian approximation we obtain analytical expressions for the correlation functions, the elasticity constant, the free energy, the pressure, and the chemical potential. We also use Ward symmetry identities to set a simple condition for the correlation functions. Subsequently we find corrections due to fluctuations and show that density now contains Legendre polynomials of higher orders.

  15. The current theoretical assumptions of the Bobath concept as determined by the members of BBTA.

    Science.gov (United States)

    Raine, Sue

    2007-01-01

    The Bobath concept is a problem-solving approach to the assessment and treatment of individuals following a lesion of the central nervous system that offers therapists a framework for their clinical practice. The aim of this study was to facilitate a group of experts in determining the current theoretical assumptions underpinning the Bobath concept.A four-round Delphi study was used. The expert sample included all 15 members of the British Bobath Tutors Association. Initial statements were identified from the literature with respondents generating additional statements. Level of agreement was determined by using a five-point Likert scale. Level of consensus was set at 80%. Eighty-five statements were rated from the literature along with 115 generated by the group. Ninety-three statements were identified as representing the theoretical underpinning of the Bobath concept. The Bobath experts agreed that therapists need to be aware of the principles of motor learning such as active participation, opportunities for practice and meaningful goals. They emphasized that therapy is an interactive process between individual, therapist, and the environment and aims to promote efficiency of movement to the individual's maximum potential rather than normal movement. Treatment was identified by the experts as having "change of functional outcome" at its center.

  16. Network Complexity Measures. An Information-Theoretic Approach.

    Directory of Open Access Journals (Sweden)

    Matthias Dehmer

    2015-04-01

    Full Text Available Quantitative graph analysis by using structural indices has been intricate in a sense that it often remains unclear which structural graph measures is the most suitable one, see [1, 12, 13]. In general, quantitative graph analysis deals with quantifying structural information of networks by using a measurement approach [5]. As special problem thereof is to characterize a graph quantitatively, that means to determine a measure that captures structural features of a network meaningfully. Various classical structural graph measures have been used to tackle this problem [13]. A fruitful approach by using information-theoretic [21] and statistical methods is to quantify the structural information content of a graph [1, 8, 18]. In this note, we sketch some classical information measures. Also, we briefly address the problem what kind of measures capture structural information uniquely. This relates to determine the discrimination power (or also called uniqueness of a graph measure, that is, how is the ability of the measures to discriminate non-isomorphic graphs structurally. [1] D. Bonchev. Information Theoretic Indices for Characterization of Chemical Structures. Research Studies Press, Chichester, 1983. [5] M. Dehmer and F. Emmert-Streib. Quantitative Graph Theory. Theory and Applications. CRC Press, 2014. [8] M. Dehmer, M. Grabner, and K. Varmuza. Information indices with high discriminative power for graphs. PLoS ONE, 7:e31214, 2012. [12] F. Emmert-Streib and M. Dehmer. Exploring statistical and population aspects of network complexity. PLoS ONE, 7:e34523, 2012. [13] F. Harary. Graph Theory. Addison Wesley Publishing Company, 1969. Reading, MA, USA. [18] A. Mowshowitz. Entropy and the complexity of the graphs I: An index of the relative complexity of a graph. Bull. Math. Biophys., 30:175–204, 1968. [21] C. E. Shannon and W. Weaver. The Mathematical Theory of Communication. University of Illinois Press, 1949.

  17. THE DINAMICS ON CITIZENSHIP – A THEORETICAL APPROACH

    Directory of Open Access Journals (Sweden)

    Diana Elena NEAGA

    2010-12-01

    Full Text Available In this paper I argue that the concept of citizenship is fundamentally a dynamic concept, a reflection of the society in which we live in. Thus, I identify participation as the main element of this dynamics. Starting from a simple definition – citizenship as the connecting point between individuals and the state trough rights and obligations – I note that citizenship is called upon on one hand in order to legitimate a political community’s authority, and on the other hand, in order to protect the individuals trough guaranteeing a set of civil, political and social rights. In order to fulfill these functions, the institution of citizenship must permit a continuous negotiation and renegotiation of the social contract, in a well-defined framework (in terms of time and place coordinates. Thus a particular mechanism emerges, transcending the classical theoretical approaches meant to explain who, how, for whom and why we discuss he issue of citizenship. My paper follows a three-step argument: first, I will start by deconstructing the concept of citizenship to its component elements, stressing out those aspects I consider to be relevant in terms of dynamics. Secondly, I will look at the main theoretical approaches regarding citizenship, considered as the results of a modeling process which establishes particular relations between various elements composing a system. Finally, I will underline the importance of participation (active or/and passive in the process of (re-constructing the concept of citizenship. Also, in this last part, I will try to synthesize the main elements that contribute to the dynamics of citizenship

  18. A Game Theoretic Approach to Cyber Attack Prediction

    Energy Technology Data Exchange (ETDEWEB)

    Peng Liu

    2005-11-28

    The area investigated by this project is cyber attack prediction. With a focus on correlation-based prediction, current attack prediction methodologies overlook the strategic nature of cyber attack-defense scenarios. As a result, current cyber attack prediction methodologies are very limited in predicting strategic behaviors of attackers in enforcing nontrivial cyber attacks such as DDoS attacks, and may result in low accuracy in correlation-based predictions. This project develops a game theoretic framework for cyber attack prediction, where an automatic game-theory-based attack prediction method is proposed. Being able to quantitatively predict the likelihood of (sequences of) attack actions, our attack prediction methodology can predict fine-grained strategic behaviors of attackers and may greatly improve the accuracy of correlation-based prediction. To our best knowledge, this project develops the first comprehensive framework for incentive-based modeling and inference of attack intent, objectives, and strategies; and this project develops the first method that can predict fine-grained strategic behaviors of attackers. The significance of this research and the benefit to the public can be demonstrated to certain extent by (a) the severe threat of cyber attacks to the critical infrastructures of the nation, including many infrastructures overseen by the Department of Energy, (b) the importance of cyber security to critical infrastructure protection, and (c) the importance of cyber attack prediction to achieving cyber security.

  19. Is DNA a metal, semiconductor or insulator? A theoretical approach

    Science.gov (United States)

    Rey-Gonzalez, Rafael; Fonseca-Romero, Karen; Plazas, Carlos; Grupo de Óptica e Información Cuántica Team

    Over the last years, scientific interest for designing and making low dimensional electronic devices with traditional or novel materials has been increased. These experimental and theoretical researches in electronic properties at molecular scale are looking for developing efficient devices able to carry out tasks which are currently done by silicon transistors and devices. Among the new materials DNA strands are highlighted, but the experimental results have been contradictories pointing to behaviors as conductor, semiconductor or insulator. To contribute to the understanding of the origin of the disparity of the measurements, we perform a numerical calculation of the electrical conductance of DNA segments, modeled as 1D disordered finite chains. The system is described into a Tight binding model with nearest neighbor interactions and a s orbital per site. Hydration effects are included as random variations of self-energies. The electronic current as a function of applied bias is calculated using Launder formalism, where the transmission probability is determined into the transfer matrix formalism. We find a conductor-to-semiconductor-to-insulator transition as a function of the three effects taken into account: chain size, intrinsic disorder, and hydration We thank Fundación para la Promoción de la Investigación y la Tecnología, Colombia, and Dirección de Investigación de Bogotá, Universidad Nacional de Colombia, for partial financial support.

  20. An integrated theoretical and practical approach for teaching hydrogeology

    Science.gov (United States)

    Bonomi, Tullia; Fumagalli, Letizia; Cavallin, Angelo

    2013-04-01

    Hydrogeology as an earth science intersects the broader disciplines of geology, engineering, and environmental studies but it does not overlap fully with any of them. It is focused on its own range of problems and over time has developed a rich variety of methods and approaches. The resolution of many hydrogeological problems requires knowledge of elements of geology, hydraulics, physics and chemistry; moreover in recent years the knowledge of modelling techniques has become a necessary ability. Successful transfer of all this knowledge to the students depends on the breadth of material taught in courses, the natural skills of the students and any practical experience the students can obtain. In the Department of Earth and Environmental Sciences of the University of Milano-Bicocca, the teaching of hydrogeology is developed in three inter-related courses: 1) general hydrogeology, 2) applied hydrogeology, 3) groundwater pollution and remediation. The sequence focuses on both groundwater flux and contaminant transport, supplemented by workshops involving case studies and computer labs, which provide the students with practical translation of the theoretical aspects of the science into the world of work. A second key aspect of the program utilizes the students' skill at learning through online approaches, and this is done through three approaches: A) by developing the courses on a University e-learning platform that allows the students to download lectures, articles, and teacher comments, and to participate in online forums; B) by carring out exercises through computer labs where the student analyze and process hydrogeological data by means of different numerical codes, that in turn enable them to manage databases and to perform aquifer test analysis, geostatistical analysis, and flux and transport modelling both in the unsaturated and saturated zone. These exercises are of course preceded by theoretical lectures on codes and software, highlighting their features and

  1. Examples of feedback, experimental and theoretical approaches for concrete durability assessment

    Directory of Open Access Journals (Sweden)

    Toutlemonde F.

    2011-04-01

    Full Text Available This paper presents some experimental data obtained from UHPFRC (Ultra-High Performance Fibre-Reinforced Concrete being exposed for 10 years in a cooling tower and a high slag content concrete being exposed for 30 years in a marine environment. Experimental data are then used for assessing concrete durability through a theoretical approach, namely performance-based analysis. The results from the application of this approach are consistent with the penetration depth of aggressive agents measured from core samples. Finally a simulation method currently being developed by EDF is presented, which has great relevance to durability assessment.

  2. Comparing Teaching Approaches About Maxwell's Displacement Current

    Science.gov (United States)

    Karam, Ricardo; Coimbra, Debora; Pietrocola, Maurício

    2014-08-01

    Due to its fundamental role for the consolidation of Maxwell's equations, the displacement current is one of the most important topics of any introductory course on electromagnetism. Moreover, this episode is widely used by historians and philosophers of science as a case study to investigate several issues (e.g. the theory-experiment relationship). Despite the consensus among physics educators concerning the relevance of the topic, there are many possible ways to interpret and justify the need for the displacement current term. With the goal of understanding the didactical transposition of this topic more deeply, we investigate three of its domains: (1) The historical development of Maxwell's reasoning; (2) Different approaches to justify the term insertion in physics textbooks; and (3) Four lectures devoted to introduce the topic in undergraduate level given by four different professors. By reflecting on the differences between these three domains, significant evidence for the knowledge transformation caused by the didactization of this episode is provided. The main purpose of this comparative analysis is to assist physics educators in developing an epistemological surveillance regarding the teaching and learning of the displacement current.

  3. A first-principles theoretical approach to heterogeneous nanocatalysis.

    Science.gov (United States)

    Negreiros, Fabio R; Aprà, Edoardo; Barcaro, Giovanni; Sementa, Luca; Vajda, Stefan; Fortunelli, Alessandro

    2012-02-21

    A theoretical approach to heterogeneous catalysis by sub-nanometre supported metal clusters and alloys is presented and discussed. Its goal is to perform a computational sampling of the reaction paths in nanocatalysis via a global search in the phase space of structures and stoichiometry combined with filtering which takes into account the given experimental conditions (catalytically relevant temperature and reactant pressure), and corresponds to an incremental exploration of the disconnectivity diagram of the system. The approach is implemented and applied to the study of propylene partial oxidation by Ag(3) supported on MgO(100). First-principles density-functional theory calculations coupled with a Reactive Global Optimization algorithm are performed, finding that: (1) the presence of an oxide support drastically changes the potential energy landscape of the system with respect to the gas phase, favoring configurations which interact positively with the electrostatic field generated by the surface; (2) the reaction energy barriers for the various mechanisms are crucial in the competition between thermodynamically and kinetically favored reaction products; (3) a topological database of structures and saddle points is produced which has general validity and can serve for future studies or for deriving general trends; (4) the MgO(100) surface captures some major features of the effect of an oxide support and appears to be a good model of a simple oxide substrate; (5) strong cooperative effects are found in the co-adsorption of O(2) and other ligands on small metal clusters. The proposed approach appears as a viable route to advance the role of predictive computational science in the field of heterogeneous nanocatalysis. This journal is © The Royal Society of Chemistry 2012

  4. A first-principles theoretical approach to heterogeneous nanocatalysis

    Science.gov (United States)

    Negreiros, Fabio R.; Aprà, Edoardo; Barcaro, Giovanni; Sementa, Luca; Vajda, Stefan; Fortunelli, Alessandro

    2012-02-01

    A theoretical approach to heterogeneous catalysis by sub-nanometre supported metal clusters and alloys is presented and discussed. Its goal is to perform a computational sampling of the reaction paths in nanocatalysis via a global search in the phase space of structures and stoichiometry combined with filtering which takes into account the given experimental conditions (catalytically relevant temperature and reactant pressure), and corresponds to an incremental exploration of the disconnectivity diagram of the system. The approach is implemented and applied to the study of propylene partial oxidation by Ag3 supported on MgO(100). First-principles density-functional theory calculations coupled with a Reactive Global Optimization algorithm are performed, finding that: (1) the presence of an oxide support drastically changes the potential energy landscape of the system with respect to the gas phase, favoring configurations which interact positively with the electrostatic field generated by the surface; (2) the reaction energy barriers for the various mechanisms are crucial in the competition between thermodynamically and kinetically favored reaction products; (3) a topological database of structures and saddle points is produced which has general validity and can serve for future studies or for deriving general trends; (4) the MgO(100) surface captures some major features of the effect of an oxide support and appears to be a good model of a simple oxide substrate; (5) strong cooperative effects are found in the co-adsorption of O2 and other ligands on small metal clusters. The proposed approach appears as a viable route to advance the role of predictive computational science in the field of heterogeneous nanocatalysis.

  5. Open-Ended Evolutionary Robotics: an Information Theoretic Approach

    CERN Document Server

    Delarboulas, Pierre; Sebag, Michèle

    2010-01-01

    This paper is concerned with designing self-driven fitness functions for Embedded Evolutionary Robotics. The proposed approach considers the entropy of the sensori-motor stream generated by the robot controller. This entropy is computed using unsupervised learning; its maximization, achieved by an on-board evolutionary algorithm, implements a "curiosity instinct", favouring controllers visiting many diverse sensori-motor states (sms). Further, the set of sms discovered by an individual can be transmitted to its offspring, making a cultural evolution mode possible. Cumulative entropy (computed from ancestors and current individual visits to the sms) defines another self-driven fitness; its optimization implements a "discovery instinct", as it favours controllers visiting new or rare sensori-motor states. Empirical results on the benchmark problems proposed by Lehman and Stanley (2008) comparatively demonstrate the merits of the approach.

  6. We need theoretical physics approaches to study living systems

    Science.gov (United States)

    Blagoev, Krastan B.; Shukla, Kamal; affil="3" >Herbert Levine,

    2013-08-01

    Living systems, as created initially by the transition from assemblies of large molecules to self-reproducing information-rich cells, have for centuries been studied via the empirical toolkit of biology. This has been a highly successful enterprise, bringing us from the vague non-scientific notions of vitalism to the modern appreciation of the biophysical and biochemical bases of life. Yet, the truly mind-boggling complexity of even the simplest self-sufficient cells, let alone the emergence of multicellular organisms, of brain and consciousness, and to ecological communities and human civilizations, calls out for a complementary approach. In this editorial, we propose that theoretical physics can play an essential role in making sense of living matter. When faced with a highly complex system, a physicist builds simplified models. Quoting Philip W Anderson's Nobel prize address, 'the art of model-building is the exclusion of real but irrelevant parts of the problem and entails hazards for the builder and the reader. The builder may leave out something genuinely relevant and the reader, armed with too sophisticated an experimental probe, may take literally a schematized model. Very often such a simplified model throws more light on the real working of nature....' In his formulation, the job of a theorist is to get at the crux of the system by ignoring details and yet to find a testable consequence of the resulting simple picture. This is rather different than the predilection of the applied mathematician who wants to include all the known details in the hope of a quantitative simulacrum of reality. These efforts may be practically useful, but do not usually lead to increased understanding. To illustrate how this works, we can look at a non-living example of complex behavior that was afforded by spatiotemporal patterning in the Belousov-Zhabotinsky reaction [1]. Physicists who worked on this system did not attempt to determine all the relevant chemical intermediates

  7. Computational approaches to analogical reasoning current trends

    CERN Document Server

    Richard, Gilles

    2014-01-01

    Analogical reasoning is known as a powerful mode for drawing plausible conclusions and solving problems. It has been the topic of a huge number of works by philosophers, anthropologists, linguists, psychologists, and computer scientists. As such, it has been early studied in artificial intelligence, with a particular renewal of interest in the last decade. The present volume provides a structured view of current research trends on computational approaches to analogical reasoning. It starts with an overview of the field, with an extensive bibliography. The 14 collected contributions cover a large scope of issues. First, the use of analogical proportions and analogies is explained and discussed in various natural language processing problems, as well as in automated deduction. Then, different formal frameworks for handling analogies are presented, dealing with case-based reasoning, heuristic-driven theory projection, commonsense reasoning about incomplete rule bases, logical proportions induced by similarity an...

  8. [Economic cost of treating pressure ulcers: a theoretical approach].

    Science.gov (United States)

    Silva, Ana Júlia; Pereira, Sandra Martins; Rodrigues, Alexandre; Rocha, Ana Paula; Varela, Jesuína; Gomes, Luís Miguel; Messias, Norberto; Carvalhal, Rosa; Luís, Rui; Mendes, Luís Filipe Pereira

    2013-08-01

    The present study consisted of a theoretical approach to the problem posed by the economic costs associated with pressure ulcers (PUs). The initial aim was to assess the target problem from a conceptual perspective and then to report the results of prevalence studies that formed the basis for investigations of the disease's economic impact. The purpose of the present article is to discuss the economic costs associated with PUs from both the global point of view (appraising their financial repercussion) and the individual point of view (addressing the intangible costs). Regarding the economic impact of the costs associated with PUs, the total cost of treatment per healthcare setting was estimated relative to the Autonomous Community of Azores. The total cost of all the PU categories was EUR 7,086,415 in the homecare setting, EUR 1,723,509 in the hospital setting, and EUR 1,002,562 in older people's homes. Therefore, the estimated total treatment cost of all the PU categories was approximately EUR 9,812,486 in Azores. However, the emotional impact of this disease imposes high costs on patients and their relatives as a function of the resultant suffering. Indeed, PUs impose high costs not only related to the treatment but also related to the intangible costs of the suffering caused to patients and their caregivers.

  9. Intelligent cognitive radio jamming - a game-theoretical approach

    Science.gov (United States)

    Dabcevic, Kresimir; Betancourt, Alejandro; Marcenaro, Lucio; Regazzoni, Carlo S.

    2014-12-01

    Cognitive radio (CR) promises to be a solution for the spectrum underutilization problems. However, security issues pertaining to cognitive radio technology are still an understudied topic. One of the prevailing such issues are intelligent radio frequency (RF) jamming attacks, where adversaries are able to exploit on-the-fly reconfigurability potentials and learning mechanisms of cognitive radios in order to devise and deploy advanced jamming tactics. In this paper, we use a game-theoretical approach to analyze jamming/anti-jamming behavior between cognitive radio systems. A non-zero-sum game with incomplete information on an opponent's strategy and payoff is modelled as an extension of Markov decision process (MDP). Learning algorithms based on adaptive payoff play and fictitious play are considered. A combination of frequency hopping and power alteration is deployed as an anti-jamming scheme. A real-life software-defined radio (SDR) platform is used in order to perform measurements useful for quantifying the jamming impacts, as well as to infer relevant hardware-related properties. Results of these measurements are then used as parameters for the modelled jamming/anti-jamming game and are compared to the Nash equilibrium of the game. Simulation results indicate, among other, the benefit provided to the jammer when it is employed with the spectrum sensing algorithm in proactive frequency hopping and power alteration schemes.

  10. Game theoretic approach for cooperative feature extraction in camera networks

    Science.gov (United States)

    Redondi, Alessandro E. C.; Baroffio, Luca; Cesana, Matteo; Tagliasacchi, Marco

    2016-07-01

    Visual sensor networks (VSNs) consist of several camera nodes with wireless communication capabilities that can perform visual analysis tasks such as object identification, recognition, and tracking. Often, VSN deployments result in many camera nodes with overlapping fields of view. In the past, such redundancy has been exploited in two different ways: (1) to improve the accuracy/quality of the visual analysis task by exploiting multiview information or (2) to reduce the energy consumed for performing the visual task, by applying temporal scheduling techniques among the cameras. We propose a game theoretic framework based on the Nash bargaining solution to bridge the gap between the two aforementioned approaches. The key tenet of the proposed framework is for cameras to reduce the consumed energy in the analysis process by exploiting the redundancy in the reciprocal fields of view. Experimental results in both simulated and real-life scenarios confirm that the proposed scheme is able to increase the network lifetime, with a negligible loss in terms of visual analysis accuracy.

  11. A game theoretic approach for trading discharge permits in rivers.

    Science.gov (United States)

    Niksokhan, Mohammad Hossein; Kerachian, Reza; Karamouz, Mohammad

    2009-01-01

    In this paper, a new Cooperative Trading Discharge Permit (CTDP) methodology is designed for estimating equitable and efficient treatment cost allocation among dischargers in a river system considering their conflicting interests. The methodology consists of two main steps: (1) initial treatment cost allocation and (2) equitable treatment cost reallocation. In the first step, a Pareto front among objectives is developed using a powerful and recently developed multi-objective genetic algorithm known as Nondominated Sorting Genetic Algorithm-II (NSGA-II). The objectives of the optimization model are considered to be the average treatment level of dischargers and a fuzzy risk of violating the water quality standards. The fuzzy risk is evaluated using the Monte Carlo analysis. The best non-dominated solution on the Pareto front, which provides the initial cost allocation to dischargers, is selected using the Young Bargaining Theory (YBT). In the second step, some cooperative game theoretic approaches are utilized to investigate how the maximum saving cost of participating dischargers in a coalition can be fairly allocated to them. The final treatment cost allocation provides the optimal trading discharge permit policies. The practical utility of the proposed methodology for river water quality management is illustrated through a realistic case study of the Zarjub river in the northern part of Iran.

  12. Exploring Job Satisfaction of Nursing Faculty: Theoretical Approaches.

    Science.gov (United States)

    Wang, Yingchen; Liesveld, Judy

    2015-01-01

    The Future of Nursing report identified the shortage of nursing faculty as 1 of the barriers to nursing education. In light of this, it is becoming increasingly important to understand the work-life of nursing faculty. The current research focused on job satisfaction of nursing faculty from 4 theoretical perspectives: human capital theory, which emphasizes the expected monetary and nonmonetary returns for any career choices; structural theory, which emphasizes the impact of institutional features on job satisfaction; positive extrinsic environment by self-determination theory, which asserts that a positive extrinsic environment promotes competency and effective outcomes at work; and psychological theory, which emphasizes the proposed relationship between job performance and satisfaction. In addition to the measures for human capital theory, institutional variables (from structural theory and self-determination theory), and productivity measures (from psychological theory), the authors also selected sets of variables for personal characteristics to investigate their effects on job satisfaction. The results indicated that variables related to human capital theory, especially salary, contributed the most to job satisfaction, followed by those related to institutional variables. Personal variables and productivity variables as a whole contributed as well. The only other variable with marginal significance was faculty's perception of institutional support for teaching.

  13. A choice-semantical approach to theoretical truth.

    Science.gov (United States)

    Andreas, Holger; Schiemer, Georg

    2016-08-01

    A central topic in the logic of science concerns the proper semantic analysis of theoretical sentences, that is sentences containing theoretical terms. In this paper, we present a novel choice-semantical account of theoretical truth based on the epsilon-term definition of theoretical terms. Specifically, we develop two ways of specifying the truth conditions of theoretical statements in a choice functional semantics, each giving rise to a corresponding logic of such statements. In order to investigate the inferential strength of these logical systems, we provide a translation of each truth definition into a modal definition of theoretical truth. Based on this, we show that the stronger notion of choice-semantical truth captures more adequately our informal semantic understanding of scientific statements. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. A Theoretical Analysis of Sideband Harmonics on the Inverter DC-link Current for an Electric Railcar

    Science.gov (United States)

    Ogawa, Tomoyuki; Wakao, Shinji; Taufiq, Jat; Kondo, Keiichiro; Terauchi, Nobuo

    The harmonics of the return current may interfere with the signaling current along with the rails. In this paper, we present the theoretical studies of the return current harmonics in the inverter-controlled DC electric railcar, aiming at contributing future work to improve the compatibility with the signaling current. We theoretically derive sideband harmonics of the DC-link current. Then, in order to verify the theoretical study, we experimentally measure the harmonics and numerically simulate the harmonics. As a result, we concluded the theoretical DC-link current is enough accurate to be utilized for the future improvement of the inverter harmonics current.

  15. Public Economy versus Planned Economy. Current Approaches and Problems

    Directory of Open Access Journals (Sweden)

    Ani Matei

    2006-03-01

    Full Text Available he present paper proposes a review of the current object and problems facing the public economy. For the past decade and a half, public economy has clearly come back in the attention of the research interests of specialists from the Central and Eastern European countries. Among these, the scientific research encompassed by the public economy area interrelates with the international trends. At a closer look, public economy appears to be a science, particularly interdisciplinary, with sociological, political, econometrical or systemic approaches possible to prevail. To continue, the author makes reference to four pillars of the public economy: optimum, welfare, social choice and economic justice that allow different approaches to develop. A science branch, equally theoretical and practical, public economy will stress its connections with the economic and mathematic modeling, systemic analysis or sociological and political research. Still, seve¬ral problems in public economy remain open. These concentrate on the public interest, intervention and decision. Conceptualization, understanding and description of the mechanisms that allow the operationalisation may form the basis for further developments on both theoretical and practical level. A clear distinction in order to justify the title of this article needs to be made. Public economy is not to be confused with planning economy. The state remains but one of the producers and delivery agents of public goods and services.

  16. Public Economy versus Planned Economy. Current Approaches and Problems

    Directory of Open Access Journals (Sweden)

    Ani Matei

    2006-01-01

    Full Text Available The present paper proposes a review of the current object and problems facing the public economy. For the past decade and a half, public economy has clearly come back in the attention of the research interests of specialists from the Central and Eastern European countries. Among these, the scientific research encompassed by the public economy area interrelates with the international trends. At a closer look, public economy appears to be a science, particularly interdisciplinary, with sociological, political, econometrical or systemic approaches possible to prevail. To continue, the author makes reference to four pillars of the public economy: optimum, welfare, social choice and economic justice that allow different approaches to develop. A science branch, equally theoretical and practical, public economy will stress its connections with the economic and mathematic modeling, systemic analysis or sociological and political research. Still, seve¬ral problems in public economy remain open. These concentrate on the public interest, intervention and decision. Conceptualization, understanding and description of the mechanisms that allow the operationalisation may form the basis for further developments on both theoretical and practical level. A clear distinction in order to justify the title of this article needs to be made. Public economy is not to be confused with planning economy. The state remains but one of the producers and delivery agents of public goods and services.

  17. On the presence of electric currents in the solar atmosphere. I - A theoretical framework

    Science.gov (United States)

    Hagyard, M.; Low, B. C.; Tandberg-Hanssen, E.

    1981-01-01

    The general magnetic field above the solar photosphere is divided by an elementary analysis based on Ampere's law into two parts: a potential field due to electric currents below the photosphere and a field produced by electric currents above the photosphere combined with the induced mirror currents. The latter, by symmetry, has a set of field lines lying in the plane taken to be the photosphere which may be constructed from given vector magnetograph measurements. These field lines also represent all the information on the electric currents above the photosphere that a magnetograph can provide. Theoretical illustrations are given, and implications for data analysis are discussed.

  18. The impact on CT dose of the variability in tube current modulation technology: a theoretical investigation

    Science.gov (United States)

    Li, Xiang; Segars, W. Paul; Samei, Ehsan

    2014-08-01

    Body CT scans are routinely performed using tube-current-modulation (TCM) technology. There is notable variability across CT manufacturers in terms of how TCM technology is implemented. Some manufacturers aim to provide uniform image noise across body regions and patient sizes, whereas others aim to provide lower noise for smaller patients. The purpose of this study was to conduct a theoretical investigation to understand how manufacturer-dependent TCM scheme affects organ dose, and to develop a generic approach for assessing organ dose across TCM schemes. The adult reference female extended cardiac-torso (XCAT) phantom was used for this study. A ray-tracing method was developed to calculate the attenuation of the phantom for a given projection angle based on phantom anatomy, CT system geometry, x-ray energy spectrum, and bowtie filter filtration. The tube current (mA) for a given projection angle was then calculated as a log-linear function of the attenuation along that projection. The slope of this function, termed modulation control strength, α, was varied from 0 to 1 to emulate the variability in TCM technology. Using a validated Monte Carlo program, organ dose was simulated for five α values (α = 0, 0.25, 0.5, 0.75, and 1) in the absence and presence of a realistic system mA limit. Organ dose was further normalized by volume-weighted CT dose index (CTDIvol) to obtain conversion factors (h factors) that are relatively independent of system specifics and scan parameters. For both chest and abdomen-pelvis scans and for 24 radiosensitive organs, organ dose conversion factors varied with α, following second-order polynomial equations. This result suggested the need for α-specific organ dose conversion factors (i.e., conversion factors specific to the modulation scheme used). On the other hand, across the full range of α values, organ dose in a TCM scan could be derived from the conversion factors established for a fixed-mA scan (hFIXED). This was possible by

  19. The Role of the Family in Genetic Testing: Theoretical Perspectives, Current Knowledge, and Future Directions

    Science.gov (United States)

    Peterson, Susan K.

    2005-01-01

    This article addresses conceptual challenges and theoretical approaches for examining the role of the family in responding and adapting to genetic testing for inherited conditions. Using a family systems perspective, family-based constructs that are relevant to genetic testing may be organized into three domains: family communication, organization…

  20. Derivation of Theoretical Formulas of Sequence Currents on Underground Cable System

    DEFF Research Database (Denmark)

    Ohno, Teruo; Ametani, Akihiro; Bak, Claus Leth

    the installation and it is difficult to predict these values beforehand with good accuracy. This paper derives theoretical formulas of the sequence currents for a cross-bonded cable and a normal-bonded cable. The accuracy of the proposed formulas is verified through a comparison with EMTP simulations....

  1. Narcolepsy: current treatment options and future approaches

    Directory of Open Access Journals (Sweden)

    Michel Billiard

    2008-06-01

    Full Text Available Michel BilliardDepartment of Neurology, Gui de Chauliac Hospital, Montpellier, FranceAbstract: The management of narcolepsy is presently at a turning point. Three main avenues are considered in this review: 1 Two tendencies characterize the conventional treatment of narcolepsy. Modafinil has replaced methylphenidate and amphetamine as the first-line treatment of excessive daytime sleepiness (EDS and sleep attacks, based on randomized, double blind, placebo-controlled clinical trials of modafinil, but on no direct comparison of modafinil versus traditional stimulants. For cataplexy, sleep paralysis, and hypnagogic hallucinations, new antidepressants tend to replace tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs in spite of a lack of randomized, double blind, placebo-controlled clinical trials of these compounds; 2 The conventional treatment of narcolepsy is now challenged by sodium oxybate, the sodium salt of gammahydroxybutyrate, based on a series of randomized, double-blind, placebo-controlled clinical trials and a long-term open label study. This treatment has a fairly good efficacy and is active on all symptoms of narcolepsy. Careful titration up to an adequate level is essential both to obtain positive results and avoid adverse effects; 3 A series of new treatments are currently being tested, either in animal models or in humans, They include novel stimulant and anticataplectic drugs, endocrine therapy, and, more attractively, totally new approaches based on the present state of knowledge of the pathophysiology of narcolepsy with cataplexy, hypocretine-based therapies, and immunotherapy.Keywords: narcolepsy, treatment, conventional drugs, modafinil, sodium oxybate, future treatments

  2. SUSTAINABLE TOURISM AND ITS FORMS - A THEORETICAL APPROACH

    Directory of Open Access Journals (Sweden)

    Bac Dorin

    2013-07-01

    Full Text Available From the second half of the twentieth century, the importance of the tourism industry to the world economy continued to grow, reaching today impressive figures: receipts of almost $ 1,000 billion and direct employment for over 70 million people (WTTC 2012, without taking into account the multiplier effect (according to the same statistics of WTTC, if considering the multiplier effect, the values are: $ 5,990 billion in tourism receipts, and 253.5 million jobs. We can say that tourism: has a higher capacity to generate and distribute incomes compared to other sectors; has a high multiplier effect; determines a high level of consumption of varied products and services. In this context, voices began to emerge, which presented the problems and challenges generated by the tourism activity. Many regions are facing real problems generated by tourism entrepreneurs and tourists who visit the community. Therefore, at the end of the last century, there were authors who sought to define a new form of tourism, which eliminated the negative impacts and increased the positive ones. As a generic term they used alternative tourism, but because of the ambiguity of the term, they tried to find a more precise term, which would define the concept easier. Thus emerged: ecotourism, rural tourism, Pro Poor Tourism etc.. All these forms have been introduced under the umbrella concept of sustainable tourism. In the present paper we will take a theoretical approach, in order to present some forms of sustainable tourism. During our research we covered the ideas and concepts promoted by several authors and academics but also some international organizations with focus on tourism. We considered these forms of tourism, as they respect all the rules of sustainable tourism and some of them have great potential to grow in both developed and emerging countries. The forms of sustainable tourism we identified are: ecotourism, pro-poor tourism, volunteer tourism and slow tourism. In

  3. Molecular Adsorption Bond Lengths at Metal Oxide Surfaces: Failure of Current Theoretical Methods

    Energy Technology Data Exchange (ETDEWEB)

    Hoeft, J.-T.; Kittel, M.; Polcik, M.; Bao, S.; Toomes, R. L.; Kang, J.-H.; Woodruff, D. P.; Pascal, M.; Lamont, C. L. A.

    2001-08-20

    New experimental structure determinations for molecular adsorbates on NiO(100) reveal much shorter Ni-C and Ni-N bond lengths for adsorbed CO and NH{sub 3} as well as NO (2.07, 1.88, 2.07{angstrom}) than previously computed theoretical values, with discrepancies up to 0.79{angstrom}, highlighting a major weakness of current theoretical descriptions of oxide-molecule bonding. Comparisons with experimentally determined bond lengths of the same species adsorbed atop Ni on metallic Ni(111) show values on the oxide surface that are consistently larger (0.1--0.3{angstrom}) than on the metal, indicating somewhat weaker bonding.

  4. Resilience or Flexibility– A Theoretical Approach on Romanian Development Regions

    Directory of Open Access Journals (Sweden)

    Roxana Voicu – Dorobanțu

    2015-09-01

    Full Text Available The paper describes a theoretical contextualization of flexibility, sustainability, durability and resilience, in the context of the sustainable development goals. The main purpose is to identify the theoretical handles that may be used in the creation of a flexibility indicator. Thus, research questions related to the theoretical differentiation between durable and sustainable, flexible and resilient are answered. Further on, the paper describes the situation of the Romanian regions in terms of development indicators, based on Eurostat data, as a premise for further research on the possibility of their leapfrogging. This work was financially supported through the project “Routes of academic excellence in doctoral and post-doctoral research- REACH” co-financed through the European Social Fund, by Sectoral Operational Programme Human Resources Development 2007-2013, contract no POSDRU/59/1.5/S/137926.

  5. Game-theoretic interference coordination approaches for dynamic spectrum access

    CERN Document Server

    Xu, Yuhua

    2016-01-01

    Written by experts in the field, this book is based on recent research findings in dynamic spectrum access for cognitive radio networks. It establishes a game-theoretic framework and presents cutting-edge technologies for distributed interference coordination. With game-theoretic formulation and the designed distributed learning algorithms, it provides insights into the interactions between multiple decision-makers and the converging stable states. Researchers, scientists and engineers in the field of cognitive radio networks will benefit from the book, which provides valuable information, useful methods and practical algorithms for use in emerging 5G wireless communication.

  6. Current and future prospects for the application of systematic theoretical methods to the study of problems in physical oceanography

    Energy Technology Data Exchange (ETDEWEB)

    Constantin, A., E-mail: adrian.constantin@kcl.ac.uk [Department of Mathematics, King' s College London, Strand, London WC2R 2LS (United Kingdom); Faculty of Mathematics, University of Vienna, Oskar-Morgenstern-Platz 1, 1090 Vienna (Austria); Johnson, R.S., E-mail: r.s.johnson@ncl.ac.uk [School of Mathematics & Statistics, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)

    2016-09-07

    Highlights: • Systematic theoretical methods in studies of equatorial ocean dynamics. • Linear wave-current interactions in stratified flows. • Exact solutions – Kelvin waves, azimuthal non-uniform currents. • Three-dimensional nonlinear currents. • Hamiltonian formulation for the governing equations and for structure-preserving/enhancing approximations. - Abstract: This essay is a commentary on the pivotal role of systematic theoretical methods in physical oceanography. At some level, there will always be a conflict between theory and experiment/data collection: Which is pre-eminent? Which should come first? This issue appears to be particularly marked in physical oceanography, to the extreme detriment of the development of the subject. It is our contention that the classical theory of fluids, coupled with methods from the theory of differential equations, can play a significant role in carrying the subject, and our understanding, forward. We outline the philosophy behind a systematic theoretical approach, highlighting some aspects of equatorial ocean dynamics where these methods have already been successful, paving the way for much more in the future and leading, we expect, to the better understanding of this and many other types of ocean flow. We believe that the ideas described here promise to reveal a rich and beautiful dynamical structure.

  7. Theoretical approaches to digital services and digital democracy

    DEFF Research Database (Denmark)

    Hoff, Jens Villiam; Scheele, Christian Elling

    2014-01-01

    The purpose of this paper is to develop a theoretical framework, which can be used in the analysis of all types of (political-administrative) web applications. Through a discussion and criticism of social construction of technology (SCOT), an earlier version of this model based on new medium theory...

  8. Semiotics and Knowledge Management (KM) : A theoretical and empirical approach

    NARCIS (Netherlands)

    Sjarbaini, Larissa; Jorna, Rene J.

    2013-01-01

    Knowledge Management (KM) concerns the study of knowledge in organizations. Knowledge sharing, use, storage, support, and knowledge creation are components of KM. The (short) history of KM shows that the theoretical foundations of KM require completion. In this article, a perspective on KM is discus

  9. Semiotics and Knowledge Management (KM) : A theoretical and empirical approach

    NARCIS (Netherlands)

    Sjarbaini, Larissa; Jorna, Rene J.

    Knowledge Management (KM) concerns the study of knowledge in organizations. Knowledge sharing, use, storage, support, and knowledge creation are components of KM. The (short) history of KM shows that the theoretical foundations of KM require completion. In this article, a perspective on KM is

  10. STRONG NORMALIZATION IN TYPE SYSTEMS - A MODEL THEORETICAL APPROACH

    NARCIS (Netherlands)

    TERLOUW, J

    1995-01-01

    Tait's proof of strong normalization for the simply typed lambda-calculus is interpreted in a general model theoretical framework by means of the specification of a certain theory T and a certain model U of T. The argumentation is partly reduced to formal predicate logic by the application of

  11. Group theoretic approaches to nuclear and hadronic collective motion

    Energy Technology Data Exchange (ETDEWEB)

    Biedenharn, L.C.

    1982-01-01

    Three approaches to nuclear and hadronic collective motion are reviewed, compared and contrasted: the standard symmetry approach as typified by the Interacting Boson Model, the kinematic symmetry group approach of Gell-Mann and Tomonaga, and the recent direct construction by Buck. 50 references.

  12. Current Cognitive Approaches to Childhood Psychopathology.

    Science.gov (United States)

    Garfield, Sol L., Ed.

    1984-01-01

    Presents six developmentally oriented articles on childhood psychopathology. Reviews research dealing with autism, social isolation, interpersonal understanding, sociomoral reasoning, cognitive controls, and aggression and includes an overview of progress and problems in the cognitive approach to clinical child psychology. (JAC)

  13. Interactions between DNA purinic bases and amodiaquine: A theoretical approach

    Directory of Open Access Journals (Sweden)

    Valdemar Lacerda Júnior

    2010-06-01

    Full Text Available We study theoretically the amodiaquine-adenine and amodiaquine-guanine adducts formation using Density Functional Theory (B3LYP and the 6-31G(d basis set for the geometry optimizations and 6-31+G(d,p for the analysis of the global indexes: electrophilicity (w, electronic chemical potential (m, hardness (h and softness (S, based in the Frontier Molecular Orbital Theory – FMO. Local softness for nucleophilic reaction (sk+ sites over guanine was evaluated using Fukui function (f k. We also evaluated the guanine Electrostatic Potential (EP values using the (MSK charge scheme. The theoretical calculations had demonstrated that the amodiaquine has greater electronic affinity for the guanine, with irreversible formation of the amodiaquine-guanine adduct, as reported before on a previous experimental work.

  14. Representing electrons a biographical approach to theoretical entities

    CERN Document Server

    Arabatzis, Theodore

    2006-01-01

    Both a history and a metahistory, Representing Electrons focuses on the development of various theoretical representations of electrons from the late 1890s to 1925 and the methodological problems associated with writing about unobservable scientific entities. Using the electron-or rather its representation-as a historical actor, Theodore Arabatzis illustrates the emergence and gradual consolidation of its representation in physics, its career throughout old quantum theory, and its appropriation and reinterpretation by chemists. As Arabatzis develops this novel biographical

  15. Recent theoretical progress on an information geometrodynamical approach to chaos

    CERN Document Server

    Cafaro, Carlo

    2008-01-01

    In this paper, we report our latest research on a novel theoretical information-geometric framework suitable to characterize chaotic dynamical behavior of arbitrary complex systems on curved statistical manifolds. Specifically, an information-geometric analogue of the Zurek-Paz quantum chaos criterion of linear entropy growth and an information-geometric characterization of chaotic (integrable) energy level statistics of a quantum antiferromagnetic Ising spin chain in a tilted (transverse) external magnetic field are presented.

  16. A Comparison of Approaches for Solving Hard Graph-Theoretic Problems

    Science.gov (United States)

    2015-05-01

    A Comparison of Approaches for Solving Hard Graph- Theoretic Problems Victoria Horan ∗ Air Force Research Laboratory Information Directorate Steve...Comparison of Approaches for Solving Hard Graph- Theoretic Problems 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...Minimizing the Size of an Identifying or Locating-Dominating Code in a Graph is NP- Hard ”, Theoret . Comput. Sci., 290 (2003) no. 3, 2109-2120. [4] M.G

  17. When the Mannequin Dies, Creation and Exploration of a Theoretical Framework Using a Mixed Methods Approach.

    Science.gov (United States)

    Tripathy, Shreepada; Miller, Karen H; Berkenbosch, John W; McKinley, Tara F; Boland, Kimberly A; Brown, Seth A; Calhoun, Aaron W

    2016-06-01

    Controversy exists in the simulation community as to the emotional and educational ramifications of mannequin death due to learner action or inaction. No theoretical framework to guide future investigations of learner actions currently exists. The purpose of our study was to generate a model of the learner experience of mannequin death using a mixed methods approach. The study consisted of an initial focus group phase composed of 11 learners who had previously experienced mannequin death due to action or inaction on the part of learners as defined by Leighton (Clin Simul Nurs. 2009;5(2):e59-e62). Transcripts were analyzed using grounded theory to generate a list of relevant themes that were further organized into a theoretical framework. With the use of this framework, a survey was generated and distributed to additional learners who had experienced mannequin death due to action or inaction. Results were analyzed using a mixed methods approach. Forty-one clinicians completed the survey. A correlation was found between the emotional experience of mannequin death and degree of presession anxiety (P framework. Using the previous approach, we created a model of the effect of mannequin death on the educational and psychological state of learners. We offer the final model as a guide to future research regarding the learner experience of mannequin death.

  18. A review of the nurtured heart approach to parenting: evaluation of its theoretical and empirical foundations.

    Science.gov (United States)

    Hektner, Joel M; Brennan, Alison L; Brotherson, Sean E

    2013-09-01

    The Nurtured Heart Approach to parenting (NHA; Glasser & Easley, 2008) is summarized and evaluated in terms of its alignment with current theoretical perspectives and empirical evidence in family studies and developmental science. Originally conceived and promoted as a behavior management approach for parents of difficult children (i.e., with behavior disorders), NHA is increasingly offered as a valuable strategy for parents of any children, despite a lack of published empirical support. Parents using NHA are trained to minimize attention to undesired behaviors, provide positive attention and praise for compliance with rules, help children be successful by scaffolding and shaping desired behavior, and establish a set of clear rules and consequences. Many elements of the approach have strong support in the theoretical and empirical literature; however, some of the assumptions are more questionable, such as that negative child behavior can always be attributed to unintentional positive reinforcement by parents responding with negative attention. On balance, NHA appears to promote effective and validated parenting practices, but its effectiveness now needs to be tested empirically.

  19. Experimental and theoretical analysis of an optical current sensor for high power systems

    Science.gov (United States)

    Brigida, A. C. S.; Nascimento, I. M.; Mendonça, S.; Costa, J. C. W. A.; Martinez, M. A. G.; Baptista, J. M.; Jorge, P. A. S.

    2013-03-01

    A magneto-optical sensor, using a dual quadrature polarimetric processing scheme, was evaluated for current metering and protection applications in high voltage lines. Sensor calibration and resolution were obtained in different operational conditions using illumination in the 1550-nm band. Results obtained indicated the feasibility of interrogating such sensor via the optical ground wire (OPGW) link installed in standard high power grids. The polarimetric bulk optical current sensor also was theoretically studied, and the effects of different sources of error considering practical deployment were evaluated. In particular, the interference from external magnetic fields in a tree-phase system was analyzed.

  20. Current theoretical models of generalized anxiety disorder (GAD): conceptual review and treatment implications.

    Science.gov (United States)

    Behar, Evelyn; DiMarco, Ilyse Dobrow; Hekler, Eric B; Mohlman, Jan; Staples, Alison M

    2009-12-01

    Theoretical conceptualizations of generalized anxiety disorder (GAD) continue to undergo scrutiny and refinement. The current paper critiques five contemporary models of GAD: the Avoidance Model of Worry and GAD [Borkovec, T. D. (1994). The nature, functions, and origins of worry. In: G. Davey & F. Tallis (Eds.), Worrying: perspectives on theory assessment and treatment (pp. 5-33). Sussex, England: Wiley & Sons; Borkovec, T. D., Alcaine, O. M., & Behar, E. (2004). Avoidance theory of worry and generalized anxiety disorder. In: R. Heimberg, C. Turk, & D. Mennin (Eds.), Generalized anxiety disorder: advances in research and practice (pp. 77-108). New York, NY, US: Guilford Press]; the Intolerance of Uncertainty Model [Dugas, M. J., Letarte, H., Rheaume, J., Freeston, M. H., & Ladouceur, R. (1995). Worry and problem solving: evidence of a specific relationship. Cognitive Therapy and Research, 19, 109-120; Freeston, M. H., Rheaume, J., Letarte, H., Dugas, M. J., & Ladouceur, R. (1994). Why do people worry? Personality and Individual Differences, 17, 791-802]; the Metacognitive Model [Wells, A. (1995). Meta-cognition and worry: a cognitive model of generalized anxiety disorder. Behavioural and Cognitive Psychotherapy, 23, 301-320]; the Emotion Dysregulation Model [Mennin, D. S., Heimberg, R. G., Turk, C. L., & Fresco, D. M. (2002). Applying an emotion regulation framework to integrative approaches to generalized anxiety disorder. Clinical Psychology: Science and Practice, 9, 85-90]; and the Acceptance-based Model of GAD [Roemer, L., & Orsillo, S. M. (2002). Expanding our conceptualization of and treatment for generalized anxiety disorder: integrating mindfulness/acceptance-based approaches with existing cognitive behavioral models. Clinical Psychology: Science and Practice, 9, 54-68]. Evidence in support of each model is critically reviewed, and each model's corresponding evidence-based therapeutic interventions are discussed. Generally speaking, the models share an

  1. Current approach to burn critical care.

    Science.gov (United States)

    Sakallioglu, A E; Haberal, M

    2007-10-01

    Burn trauma is a frequent cause of morbidity and mortality all over the world. Advancements in resuscitation, surgical tecniques, infection control and nutritional/metaolic support decreased mortality and morbidity. This article intends to review current outlines for initial treatment and resuscitation nutritional/metabolic support and wound management peculiar to burn patients.

  2. Game Theoretic Approach to Post-Docked Satellite Control

    Science.gov (United States)

    Hiramatsu, Takashi; Fitz-Coy, Norman G.

    2007-01-01

    This paper studies the interaction between two satellites after docking. In order to maintain the docked state with uncertainty in the motion of the target vehicle, a game theoretic controller with Stackelberg strategy to minimize the interaction between the satellites is considered. The small perturbation approximation leads to LQ differential game scheme, which is validated to address the docking interactions between a service vehicle and a target vehicle. The open-loop solution are compared with Nash strategy, and it is shown that less control efforts are obtained with Stackelberg strategy.

  3. Current approaches to gene regulatory network modelling

    Directory of Open Access Journals (Sweden)

    Brazma Alvis

    2007-09-01

    Full Text Available Abstract Many different approaches have been developed to model and simulate gene regulatory networks. We proposed the following categories for gene regulatory network models: network parts lists, network topology models, network control logic models, and dynamic models. Here we will describe some examples for each of these categories. We will study the topology of gene regulatory networks in yeast in more detail, comparing a direct network derived from transcription factor binding data and an indirect network derived from genome-wide expression data in mutants. Regarding the network dynamics we briefly describe discrete and continuous approaches to network modelling, then describe a hybrid model called Finite State Linear Model and demonstrate that some simple network dynamics can be simulated in this model.

  4. Thalassemia: current approach to an old disease.

    Science.gov (United States)

    Lo, Louise; Singer, Sylvia Titi

    2002-12-01

    This article discusses the approach for recognition, diagnosis, and management of the thalassemias, and reviews new prospects of therapy, focusing mostly on the beta-thalassemias--the more severe and clinically important type, beta-thalassemia major is typically treated with regular transfusion and chelation therapy. New strategies for specific therapy including monitoring of iron induced organ damage, fetal hemoglobin augmentation as an alternative for transfusions, bone marrow transplantation offer hope for prevention of complications and better care of the beta-thalassemias.

  5. Scientifically-theoretical approaches to the definition of "managerial innovations"

    OpenAIRE

    Mushnikova, S.

    2011-01-01

    Based on analysis of existing approaches to the definition of "management " and "innovation" in the investigation of the author 's interpretation of "managerial innovations". The necessity of introduction of managerial innovations in the conditions of operation of industrial enterprises.

  6. On Tradeoffs between Trust and Survivability using a Game Theoretic Approach

    Science.gov (United States)

    2016-04-13

    networks. In: Pro . 6th Annual ACM/IEEE Mobile Computing and Networking, pp.255- 265, Boston, MA (Aug. 2000) 14. Ng, S.K., Seah, W.K.G.: Game ...On Tradeoffs between Trust and Survivability using a Game Theoretic Approach Jin-Hee Cho and Ananthram Swami U.S. Army Research Laboratory...introduces a game theoretic approach, namely Aoyagi’s game theory based on positive collusion of players. This approach improves group trust by

  7. Current Approaches in the Treatment of Prostatitis

    Directory of Open Access Journals (Sweden)

    Volkan Izol

    2013-02-01

    Full Text Available Prostatitis is an infection or inflammation of the prostate gland that presents as several syndromes with varying clinical features. This painful condition mostly affects young and middle-aged men and diminishes their quality of life. With the recent introduction of a new classification for this disease, more effective approach for the evaluation and management of the patients with chronic pelvic pain syndrome has emerged. Nonetheless, no definitely effective treatment regime has yet been described in the literature. [Archives Medical Review Journal 2013; 22(1.000: 130-140

  8. THEORETICAL APPROACHES TO THE DESCRIPTION OF PERSONAL LEARNING ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Sergey Alexandrovich Zolotukhin

    2015-01-01

    Full Text Available Personal learning environment is a relatively new concept that emerged under the influence of the increasing popularity of Web 2.0 applications and critical understanding of hierarchical systems of distant learning. In the center of this concept is the effect of personalization, according to which the activity of the actor is an important factor of personal development, strengthening of subjectivity of learning, development of learning through social and other types of interaction. The article highlights general theoretical basics of building a personal learning environment as one of the directions of development of modern models of learning, its basic characteristics. Special attention is paid to consideration of one of the variants of constructing personal learning environment – institutional personal learning environment, which combines the benefits of distance learning and the advantages of flexible, adaptive, open educational environments. In a broader sense, an institutional personal learning environment is a mechanism for the integration of formal and informal educational environments.

  9. A Theoretical Approach to Engineering a New Enzyme

    Science.gov (United States)

    Anderson, Greg; Behera, Raghu N.; Gomatam, Ravi

    2016-08-01

    Density function theory, a subfield of quantum mechanics (QM), in combination with molecular mechanics (MM) has opened the way to engineer new artificial enzymes. Herein, we report theoretical calculations done using QM/MM to examine whether the regioselectivity and rate of chlorination of the enzyme chloroperoxidase can be improved by replacing the vanadium of this enzyme with niobium through dialysis. Our calculations show that a niobium substituted chloroperoxidase will be able to enter the initial steps of the catalytic cycle for chlorination. Although the protonation state of the niobium substituted enzyme is calculated to be different from than that of the natural vanadium substituted enzyme, our calculations show that the catalytic cycle can still proceed forward. Using natural bond orbitals, we analyse the electronic differences between the niobium substituted enzyme and the natural enzyme. We conclude by briefly examining how good of a model QM/MM provides for understanding the mechanism of catalysis of chloroperoxidase.

  10. A theoretical approach on controlling agricultural pest by biological controls.

    Science.gov (United States)

    Mondal, Prasanta Kumar; Jana, Soovoojeet; Kar, T K

    2014-03-01

    In this paper we propose and analyze a prey-predator type dynamical system for pest control where prey population is treated as the pest. We consider two classes for the pest namely susceptible pest and infected pest and the predator population is the natural enemy of the pest. We also consider average delay for both the predation rate i.e. predation to the susceptible pest and infected pest. Considering a subsystem of original system in the absence of infection, we analyze the existence of all possible non-negative equilibria and their stability criteria for both the subsystem as well as the original system. We present the conditions for transcritical bifurcation and Hopf bifurcation in the disease free system. The theoretical evaluations are demonstrated through numerical simulations.

  11. Strength of wood versus rate of testing - A theoretical approach

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    2007-01-01

    Strength of wood is normally measured in ramp load experiments. Experience shows that strength increases with increasing rate of testing. This feature is considered theoretically in this paper. It is shown that the influence of testing rate is a phenomenon, which depends on the quality...... of the considered wood. Low quality wood shows lesser influence of testing rate. This observation agrees with the well-known statement made by Borg Madsen that weak wood subjected to a constant load, has a longer lifetime than strong wood. In general, the influence of testing rate on strength increases...... with increasing moisture content. This phenomenon applies irrespective of the considered wood quality such that the above-mentioned order of magnitude observations between low and high quality wood are kept....

  12. Graph theoretical similarity approach to compare molecular electrostatic potentials.

    Science.gov (United States)

    Marín, Ray M; Aguirre, Nestor F; Daza, Edgar E

    2008-01-01

    In this work we introduce a graph theoretical method to compare MEPs, which is independent of molecular alignment. It is based on the edit distance of weighted rooted trees, which encode the geometrical and topological information of Negative Molecular Isopotential Surfaces. A meaningful chemical classification of a set of 46 molecules with different functional groups was achieved. Structure--activity relationships for the corticosteroid binding affinity (CBG) of 31 steroids by means of hierarchical clustering resulted in a clear partitioning in high, intermediate, and low activity groups, whereas the results from quantitative structure--activity relationships, obtained from a partial least-squares analysis, showed comparable or better cross-validated correlation coefficients than the ones reported for previous methods based solely in the MEP.

  13. A Game Theoretic Approach to Distributed Opportunistic Scheduling

    CERN Document Server

    Banchs, Albert; Serrano, Pablo; Widmer, Joerg

    2011-01-01

    Distributed Opportunistic Scheduling (DOS) is inherently harder than conventional opportunistic scheduling due to the absence of a central entity that has knowledge of all the channel states. With DOS, stations contend for the channel using random access; after a successful contention, they measure the channel conditions and only transmit in case of a good channel, while giving up the transmission opportunity when the channel conditions are poor. The distributed nature of DOS systems makes them vulnerable to selfish users: by deviating from the protocol and using more transmission opportunities, a selfish user can gain a greater share of the wireless resources at the expense of the well-behaved users. In this paper, we address the selfishness problem in DOS from a game theoretic standpoint. We propose an algorithm that satisfies the following properties: (i) when all stations implement the algorithm, the wireless network is driven to the optimal point of operation, and (ii) one or more selfish stations cannot...

  14. Exploring the joint measurability using an information-theoretic approach

    Science.gov (United States)

    Hsu, Li-Yi

    2016-10-01

    We explore the legal purity parameters for the joint measurements. Instead of direct unsharpening the measurements, we perform the quantum cloning before the sharp measurements. The necessary fuzziness in the unsharp measurements is equivalently introduced in the imperfect cloning process. Based on the information causality and the consequent noisy nonlocal computation, one can derive the information-theoretic quadratic inequalities that must be satisfied by any physical theory. On the other hand, to guarantee the classicality, the linear Bell-type inequalities deduced by these quadratic ones must be obeyed. As for the joint measurability, the purity parameters must be chosen to obey both types of inequalities. Finally, the quadratic inequalities for purity parameters in the joint measurability region are derived.

  15. A game-theoretical approach to multimedia social networks security.

    Science.gov (United States)

    Liu, Enqiang; Liu, Zengliang; Shao, Fei; Zhang, Zhiyong

    2014-01-01

    The contents access and sharing in multimedia social networks (MSNs) mainly rely on access control models and mechanisms. Simple adoptions of security policies in the traditional access control model cannot effectively establish a trust relationship among parties. This paper proposed a novel two-party trust architecture (TPTA) to apply in a generic MSN scenario. According to the architecture, security policies are adopted through game-theoretic analyses and decisions. Based on formalized utilities of security policies and security rules, the choice of security policies in content access is described as a game between the content provider and the content requester. By the game method for the combination of security policies utility and its influences on each party's benefits, the Nash equilibrium is achieved, that is, an optimal and stable combination of security policies, to establish and enhance trust among stakeholders.

  16. Current approaches in atrial fibrillation treatment

    Directory of Open Access Journals (Sweden)

    Cenk Sarı

    2014-09-01

    Full Text Available Atrial fibrillation (AF is the most common sustained arrhythmia encountered in clinical practice. Its incidence increases with age. AF is classified into subtypes according to the duration and/or able to provide sinus rhytym. İnitially, patients should be evaluated for rhythm or rate control for appropriate treatment. Second stage of strategy aimed to investigate the feasibility of anticoagulation therapy. Recently, due to the progress made in treatment with rhythm control and anticoagulation therapy, either American or European guidelines have been renovated. These developments have taken place in the newly published guide. In this article, the current change in the management of AF is discussed.

  17. Mating strategies in primates: a game theoretical approach to infanticide.

    Science.gov (United States)

    Lyon, James E; Pandit, Sagar A; van Schaik, Carel P; Pradhan, Gauri R

    2011-04-07

    Infanticide by newly immigrated or newly dominant males is reported among a variety of taxa, such as birds, rodents, carnivores and primates. Here we present a game theoretical model to explain the presence and prevalence of infanticide in primate groups. We have formulated a three-player game involving two males and one female and show that the strategies of infanticide on the males' part and polyandrous mating on the females' part emerge as Nash equilibria that are stable under certain conditions. Moreover, we have identified all the Nash equilibria of the game and arranged them in a novel hierarchical scheme. Only in the subspace spanned by the males are the Nash equilibria found to be strict, and hence evolutionarily stable. We have therefore proposed a selection mechanism informed by adaptive dynamics to permit the females to transition to, and remain in, optimal equilibria after successive generations. Our model concludes that polyandrous mating by females is an optimal strategy for the females that minimizes infanticide and that infanticide confers advantage to the males only in certain regions of parameter space. We have shown that infanticide occurs during turbulent changes accompanying male immigration into the group. For changes in the dominance hierarchy within the group, we have shown that infanticide occurs only in primate groups where the chance for the killer to sire the next infant is high. These conclusions are confirmed by observations in the wild. This model thus has enabled us to pinpoint the fundamental processes behind the reproductive decisions of the players involved, which was not possible using earlier theoretical studies.

  18. A study of brain networks associated with swallowing using graph-theoretical approaches.

    Directory of Open Access Journals (Sweden)

    Bo Luan

    Full Text Available Functional connectivity between brain regions during swallowing tasks is still not well understood. Understanding these complex interactions is of great interest from both a scientific and a clinical perspective. In this study, functional magnetic resonance imaging (fMRI was utilized to study brain functional networks during voluntary saliva swallowing in twenty-two adult healthy subjects (all females, [Formula: see text] years of age. To construct these functional connections, we computed mean partial correlation matrices over ninety brain regions for each participant. Two regions were determined to be functionally connected if their correlation was above a certain threshold. These correlation matrices were then analyzed using graph-theoretical approaches. In particular, we considered several network measures for the whole brain and for swallowing-related brain regions. The results have shown that significant pairwise functional connections were, mostly, either local and intra-hemispheric or symmetrically inter-hemispheric. Furthermore, we showed that all human brain functional network, although varying in some degree, had typical small-world properties as compared to regular networks and random networks. These properties allow information transfer within the network at a relatively high efficiency. Swallowing-related brain regions also had higher values for some of the network measures in comparison to when these measures were calculated for the whole brain. The current results warrant further investigation of graph-theoretical approaches as a potential tool for understanding the neural basis of dysphagia.

  19. New approach for the determination of aerosol refractive indices - Part I: Theoretical bases and numerical methodology

    Science.gov (United States)

    Herbin, H.; Pujol, O.; Hubert, P.; Petitprez, D.

    2017-10-01

    The knowledge of aerosol complex refractive indices on wide spectral range with high spectral resolution is important for many research fields and applications. Various combinations of experimental/theoretical/numerical approaches have been employed to determine the optical indices of aerosol particles. However, each approach has its own advantages and limitations that restrict its generalization. This article is first part of a work aimed at proposing a new technique for determining the optical constants of aerosols. Experimentally, the method is based on recording transmittance spectra of an aerosol flow from thermal infrared to UV-visible combined with the size distribution measurements. Herein, we present the theoretical and numerical bases of the algorithm developed to retrieve the imaginary and real parts of refractive indices. This model associates the Mie theory, the single subtractive Kramers-Kronig relations, and the optimal estimation method with an iterative process. In order to quantify the capabilities of the algorithm to retrieve complex refractive indices, inverse calculations are performed from simulated extinction spectra of Quartz particles whose some of optical properties are available in the literature. We have detailed each step of the procedure and performed some comparisons with the most currently employed methods. The impact of experimental accuracy and numerical simulation are investigated in terms of errors, and uncertainties on the retrieved real and imaginary parts of the complex optical index.

  20. MEMS Packaging - Current Issues and Approaches

    Energy Technology Data Exchange (ETDEWEB)

    DRESSENDORFER,PAUL V.; PETERSON,DAVID W.; REBER,CATHLEEN ANN

    2000-01-19

    The assembly and packaging of MEMS (Microelectromechanical Systems) devices raise a number of issues over and above those normally associated with the assembly of standard microelectronic circuits. MEMS components include a variety of sensors, microengines, optical components, and other devices. They often have exposed mechanical structures which during assembly require particulate control, space in the package, non-contact handling procedures, low-stress die attach, precision die placement, unique process schedules, hermetic sealing in controlled environments (including vacuum), and other special constraints. These constraints force changes in the techniques used to separate die on a wafer, in the types of packages which can be used in the assembly processes and materials, and in the sealing environment and process. This paper discusses a number of these issues and provides information on approaches being taken or proposed to address them.

  1. The Acquisition of Chinese Relative Clauses: Contrasting Two Theoretical Approaches

    Science.gov (United States)

    Hu, Shenai; Gavarró, Anna; Vernice, Mirta; Guasti, Maria Teresa

    2016-01-01

    This study examines the comprehension of relative clauses by Chinese-speaking children, and evaluates the validity of the predictions of the Dependency Locality Theory (Gibson, 1998, 2000) and the Relativized Minimality approach (Friedmann, Belletti & Rizzi, 2009). One hundred and twenty children from three to eight years of age were tested by…

  2. THEORETICAL APPROACHES TO THE DEFINITION OF THE "INFORMATION RESOURCE"

    OpenAIRE

    Netreba, I.

    2014-01-01

    Existing approaches to determining the nature of the category "information resource" are detailed and systematized. The relationships between the categories "information resource", "information technology", "information management system" are revealed. Determined the importance of information resources for the production process at the enterprise.

  3. Conflicts, development and natural resources : An applied game theoretic approach

    NARCIS (Netherlands)

    Wick, A.K.

    2008-01-01

    This thesis also provides a critical view on a part of preceding resource curse results, namely the negative association between resources and economic performance. Arguing that the empirical literature on the topic up until now has ignored serious econometric concerns, a different approach is offer

  4. Current endoscopic approach to indeterminate biliary strictures

    Institute of Scientific and Technical Information of China (English)

    David W Victor; Stuart Sherman; Tarkan Karakan; Mouen A Khashab

    2012-01-01

    Biliary strictures are considered indeterminate when basic work-up,including transabdominal imaging and endoscopic retrograde cholangiopancreatography with routine cytologic brushing,are non-diagnostic.Indeterminate biliary strictures can easily be mischaracterized which may dramatically affect patient's outcome.Early and accurate diagnosis of malignancy impacts not only a patient's candidacy for surgery,but also potential timely targeted chemotherapies.A significant portion of patients with indeterminate biliary strictures have benign disease and accurate diagnosis is,thus,paramount to avoid unnecessary surgery.Current sampling strategies have suboptimal accuracy for the diagnosis of malignancy.Emerging data on other diagnostic modalities,such as ancillary cytology techniques,single operator cholangioscopy,and endoscopic ultrasonography-guided fine needle aspiration,revealed promising results with much improved sensitivity.

  5. Current approach to cutaneous mastocytosis in childhood.

    Science.gov (United States)

    Tamay, Zeynep; Özçeker, Deniz

    2016-09-01

    Mastocytosis is a heterogeneous disorder characterized by clonal proliferation and accumulation of mast cells in one of more organs which may lead to different clinical pictures. Pathological increase and activation of mast cells in various tissues can cause different clinical pictures. Cutaneous mastocytosis limited to the skin is the most typical clinical picture observed in children and systemic mastocytosis is very rare in the pediatric age group. The diagnosis of cutaneous mastocytosis is based on clinical findings, but is often delayed due to lack of clinical awareness of the disease and lack of its consideration in the differential diagnosis. This article focuses on the current diagnosis, management and treatment of cutaneous mastocytosis in children in order to increase awareness about this issue.

  6. Catastrophic antiphospholipid syndrome: The current management approach.

    Science.gov (United States)

    Rodriguez-Pintó, Ignasi; Espinosa, Gerard; Cervera, Ricard

    2016-04-01

    The current recommendation for catastrophic antiphospholipid syndrome (CAPS) management is the standard triple therapy with anticoagulation (AC), glucocorticoids (GCs), plasma exchange (PE), and/or intravenous immunoglobulins (IVIGs). Of note, only AC has a significant effect on the prognosis of these patients. However, from the experimental or basic point of view, there is only indirect evidence to advocate the use of these immunomodulatory therapies (GC, PE, and IVIG) in CAPS. Recently, there have been reports of severe or refractory CAPS patients treated with the monoclonal antibodies rituximab and eculizumab. The first blocks CD20, a surface protein expressed on the cytoplasmic membrane of B cells, and decreases the generation of pathogenic autoantibodies such as antiphospholipid (aPL) antibodies. The second binds with high affinity to C5 complement protein, inhibiting its cleavage and thus preventing the generation of C5b-C9 complex. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Current therapeutic approaches for plantar fasciitis

    Directory of Open Access Journals (Sweden)

    Martinelli N

    2014-03-01

    Full Text Available Nicolò Martinelli, Carlo Bonifacini, Giovanni RomeoDepartment of Ankle and Foot Surgery, IRCCS Galeazzi Orthopaedic Institute, Milan, ItalyAbstract: Almost 1 million Americans are affected by plantar fasciitis (PF, which is the commonest cause of chronic heel pain. This condition is often managed conservatively, and many rehabilitation protocols, some with the aid of orthoses, have been adopted, with good-to-excellent clinical results. Although most cases of chronic PF can be successfully managed with a conservative approach, alternative treatments, including high-energy shock wave therapy and corticosteroid injections, are commonly accepted as second-line treatment when traditional conservative therapy fails. However, surgery is still an important mode of treatment. Recently, new minimally invasive surgical techniques that offer numerous advantages (faster recovery time, early weight-bearing, lower postoperative pain over standard surgical approaches have been proposed, with good results and low complication rates. The purpose of this review is to report new conservative and surgical techniques for the treatment of PF. A literature search for articles about plantar fasciitis was conducted on the PubMed database in order to identify publications addressing the treatments of PF. The literature suggests that, initially, traditional conservative treatments consisting of rest, oral nonsteroidal anti-inflammatory drugs, foot orthotics, and stretching exercises can be tried for several weeks. In patients with chronic recalcitrant PF, extracorporeal shock wave therapy or corticosteroid injection can be considered. Surgery (minimally invasive techniques should be considered only after failure of the conservative treatments.Keywords: heel pain, surgery, plantar fasciosis

  8. Theoretical model of gravitational perturbation of current collector axisymmetric flow field

    Science.gov (United States)

    Walker, John S.; Brown, Samuel H.; Sondergaard, Neal A.

    1990-05-01

    Some designs of liquid-metal current collectors in homopolar motors and generators are essentially rotating liquid-metal fluids in cylindrical channels with free surfaces and will, at critical rotational speeds, become unstable. An investigation at David Taylor Research Center is being performed to understand the role of gravity in modifying this ejection instability. Some gravitational effects can be theoretically treated by perturbation techniques on the axisymmetric base flow of the liquid metal. This leads to a modification of previously calculated critical-current-collector ejection values neglecting gravity effects. The purpose of this paper is to document the derivation of the mathematical model which determines the perturbation of the liquid-metal base flow due to gravitational effects. Since gravity is a small force compared with the centrifugal effects, the base flow solutions can be expanded in inverse powers of the Froude number and modified liquid-flow profiles can be determined as a function of the azimuthal angle. This model will be used in later work to theoretically study the effects of gravity on the ejection point of the current collector.

  9. Trust Dynamics in WSNs: An Evolutionary Game-Theoretic Approach

    Directory of Open Access Journals (Sweden)

    Shigen Shen

    2016-01-01

    Full Text Available A sensor node (SN in Wireless Sensor Networks (WSNs can decide whether to collaborate with others based on a trust management system (TMS by making a trust decision. In this paper, we study the trust decision and its dynamics that play a key role to stabilize the whole network using evolutionary game theory. When SNs are making their decisions to select action Trust or Mistrust, a WSNs trust game is created to reflect their utilities. An incentive mechanism bound with one SN’s trust degree is incorporated into this trust game and effectively promotes SNs to select action Trust. The replicator dynamics of SNs’ trust evolution, illustrating the evolutionary process of SNs selecting their actions, are given. We then propose and prove the theorems indicating that evolutionarily stable strategies can be attained under different parameter values, which supply theoretical foundations to devise a TMS for WSNs. Moreover, we can find out the conditions that will lead SNs to choose action Trust as their final behavior. In this manner, we can assure WSNs’ security and stability by introducing a trust mechanism to satisfy these conditions. Experimental results have confirmed the proposed theorems and the effects of the incentive mechanism.

  10. Modelling Crowd Dynamics: a Multiscale, Measure-theoretical Approach

    CERN Document Server

    Evers, Joep

    2011-01-01

    We present a strategy capable of describing basic features of the dynamics of crowds. The behaviour of the crowd is considered from a twofold perspective. We examine both the large scale behaviour of the crowd, and phenomena happening at the individual pedestrian's level. We unify micro and macro in a single model, by working with general mass measures and their transport. We improve existing modelling by coupling a measure-theoretical framework with basic ideas of mixture theory formulated in terms of measures. This strategy allows us to define several constituents of the crowd, each having its own partial velocity. We can thus examine the interaction between subpopulations that have distinct characteristics. We give special features to those pedestrians that are represented by the microscopic (discrete) part. In real life they would play the role of leaders, predators etc. Since we are interested in the global behaviour of the rest of the crowd, we model this part as a continuum. By identifying a suitable c...

  11. Oxidative dissolution of silver nanoparticles: A new theoretical approach.

    Science.gov (United States)

    Adamczyk, Zbigniew; Oćwieja, Magdalena; Mrowiec, Halina; Walas, Stanisław; Lupa, Dawid

    2016-05-01

    A general model of an oxidative dissolution of silver particle suspensions was developed that rigorously considers the bulk and surface solute transport. A two-step surface reaction scheme was proposed that comprises the formation of the silver oxide phase by direct oxidation and the acidic dissolution of this phase leading to silver ion release. By considering this, a complete set of equations is formulated describing oxygen and silver ion transport to and from particles' surfaces. These equations are solved in some limiting cases of nanoparticle dissolution in dilute suspensions. The obtained kinetic equations were used for the interpretation of experimental data pertinent to the dissolution kinetics of citrate-stabilized silver nanoparticles. In these kinetic measurements the role of pH and bulk suspension concentration was quantitatively evaluated by using the atomic absorption spectrometry (AAS). It was shown that the theoretical model adequately reflects the main features of the experimental results, especially the significant increase in the dissolution rate for lower pH. Also the presence of two kinetic regimes was quantitatively explained in terms of the decrease in the coverage of the fast dissolving oxide layer. The overall silver dissolution rate constants characterizing these two regimes were determined.

  12. A field theoretical approach to the quasi-continuum method

    Science.gov (United States)

    Iyer, Mrinal; Gavini, Vikram

    2011-08-01

    The quasi-continuum method has provided many insights into the behavior of lattice defects in the past decade. However, recent numerical analysis suggests that the approximations introduced in various formulations of the quasi-continuum method lead to inconsistencies—namely, appearance of ghost forces or residual forces, non-conservative nature of approximate forces, etc.—which affect the numerical accuracy and stability of the method. In this work, we identify the source of these errors to be the incompatibility of using quadrature rules, which is a local notion, on a non-local representation of energy. We eliminate these errors by first reformulating the extended interatomic interactions into a local variational problem that describes the energy of a system via potential fields. We subsequently introduce the quasi-continuum reduction of these potential fields using an adaptive finite-element discretization of the formulation. We demonstrate that the present formulation resolves the inconsistencies present in previous formulations of the quasi-continuum method, and show using numerical examples the remarkable improvement in the accuracy of solutions. Further, this field theoretic formulation of quasi-continuum method makes mathematical analysis of the method more amenable using functional analysis and homogenization theories.

  13. Optical trimer: A theoretical physics approach to waveguide couplers

    CERN Document Server

    Stoffel, A; Rodríguez-Lara, B M

    2016-01-01

    We study electromagnetic field propagation through an ideal, passive, triangular three-waveguide coupler using a symmetry based approach to take advantage of the underlying $SU(3)$ symmetry. The planar version of this platform has proven valuable in photonic circuit design providing optical sampling, filtering, modulating, multiplexing, and switching. We show that a group-theory approach can readily provide a starting point for design optimization of the triangular version. Our analysis is presented as a practical tutorial on the use of group theory to study photonic lattices for those not familiar with abstract algebra methods. In particular, we study the equilateral trimer to show the relation of pearl-necklace arrays with the Discrete Fourier Transform due to their cyclic group symmetry, and the isosceles trimer to show its relation with the golden ratio and its ability to provide stable output at a single waveguide. We also study the propagation dependent case of an equilateral trimer that linearly increa...

  14. Coordination-theoretic approach to modelling grid service composition process

    Institute of Scientific and Technical Information of China (English)

    Meng Qian; Zhong Liu; Jing Wang; Li Yao; Weiming Zhang

    2010-01-01

    A grid service composite process is made up of complex coordinative activities.Developing the appropriate model of grid service coordinative activities is an important foundation for the grid service composition.According to the coordination theory,this paper elaborates the process of the grid service composition by using UML 2.0,and proposes an approach to modelling the grid service composition process based on the coordination theory.This approach helps not only to analyze accurately the task activities and relevant dependencies among task activities,but also to facilitate the adaptability of the grid service orchestration to further realize the connectivity,timeliness,appropriateness and expansibility of the grid service composition.

  15. CURRENT APPROACHES TO CHEMORADIOTHERAPY FOR MALIGNANT GLIOMAS

    Directory of Open Access Journals (Sweden)

    Ye. L. Choinzonov

    2014-01-01

    Full Text Available High-grade malignant gliomas (WHO grade G III–IV account for more than 50% of all primary brain tumors. Despite aggressive treatment, survival rates are still very low with a median reported survival of no more than 1.5 years.Radiation therapy is an integral part of the combined treatment, but often does not influence lethally on resistant tumor cells. Thereby, in recent decades there has been an active search for novel approaches to the treatment of malignant gliomas (chemotherapeutic drugs, biological modifiers, local hyperthermia. Experimental data showed that the effect of high temperatures has both a direct damaging effect on tumor cells and a sensitizing effect. Significant advantages are achieved when the complex treatment of different malignant tumorsincludes local hyperthermia. However data on the treatment of patients with primary and recurrent gliomas G III–IV using local hyperthermia are scarce.The literature review is given in the article provides an overview of the existing treatment methods for brain tumors.

  16. Simple field theoretical approach of Coulomb systems. Entropic effects

    Energy Technology Data Exchange (ETDEWEB)

    Di Caprio, D; Badiali, J P [Laboratory of Electrochemistry and Analytical Chemistry, University Paris 6, CNRS, ENSCP, BP 39, 4, Place Jussieu, 75252 Paris, Cedex 05 (France); Holovko, M [Institute for Condensed Matter Physics, National Academy of Sciences, 1 Svientsitskii Str, 79011 Lviv (Ukraine)], E-mail: dung.di_caprio@upmc.fr

    2009-05-29

    We discuss a new simple field theory approach of Coulomb systems. Using a description in terms of fields, we introduce in a new way the statistical degrees of freedom in relation to the quantum mechanics. We show by a series of examples that these fundamental entropic effects can help account for physical phenomena in relation to Coulomb systems whether symmetric or asymmetric in valence. Overall, this gives a new understanding of these systems.

  17. The Case Study Approach: Some Theoretical, Methodological and Applied Considerations

    Science.gov (United States)

    2013-06-01

    a large manufacturing organisation in Malaysia . An in- depth case study process (specifically a qualitative approach) was used to illustrate the...researcher closely examined four leaders from generally diverse organisations, who had embraced the learning-organisation concept in order to improve...The researchers focused on the context of learning in the workplace , and they investigated the nature of learning and development opportunities that

  18. Data normalization in biosurveillance: an information-theoretic approach.

    Science.gov (United States)

    Peter, William; Najmi, Amir H; Burkom, Howard

    2007-10-11

    An approach to identifying public health threats by characterizing syndromic surveillance data in terms of its surprisability is discussed. Surprisability in our model is measured by assigning a probability distribution to a time series, and then calculating its entropy, leading to a straightforward designation of an alert. Initial application of our method is to investigate the applicability of using suitably-normalized syndromic counts (i.e., proportions) to improve early event detection.

  19. Success Determination by Innovation: A Theoretical Approach in Marketing

    OpenAIRE

    Raj Kumar Gautam

    2012-01-01

    The paper aims at to identify the main issues in the marketing which needs immediate attention of the marketers. The importance of innovation in the marketing has also been highlighted and marketing mix have been related to innovative and creative ideas. The study is based on the secondary data, various research papers, articles has been studied to develop a innovative approach in the marketing. Marketing innovative ideas relating to business lead generation, product, price, distribution, pro...

  20. The Economic Security of Bank: Theoretical Basis and Systemic Approach

    Directory of Open Access Journals (Sweden)

    Gavlovska Nataliia I.

    2017-07-01

    Full Text Available The article analyzes the existing approaches to interpreting the category of «economic security of bank». A author’s own definition of the concept of «economic security of bank» has been proposed, which should be understood as condition of protecting the vital interests of bank, achieved by harmonizing relationships with the entities of external influence and optimizing the internal system processes, thus enabling efficient function as well as development by means of an adaptation mechanism. A number of approaches to understanding the substance of the above concept has been allocated and their main characteristics have been provided. The need to study the specifics of interaction of banking institutions with the external environment in the context of interaction between the State agents and market actors has been underlined. Features of formation of the term of «system» have been defined, three main groups of approaches to interpretation of the term have been provided. A author’s own definition of the concept of «economic security system of bank» has been proposed. A concrete definition of principles for building an economic security system of bank has been provided.

  1. Pulp regeneration: Current approaches and future challenges

    Directory of Open Access Journals (Sweden)

    Jingwen eYANG

    2016-03-01

    Full Text Available Regenerative endodontics aims to replace inflamed/necrotic pulp tissues with regenerated pulp-like tissues to revitalize teeth and improve life quality. Pulp revascularization case reports, which showed successful clinical and radiographic outcomes, indicated the possible clinical application of pulp regeneration via cell homing strategy. From a clinical point of view, functional pulp-like tissues should be regenerated with the characterization of vascularization, re-innervation, and dentin deposition with a regulated rate similar to that of normal pulp. Efficient root canal disinfection and proper size of the apical foramen are the two requisite preconditions for pulp regeneration. Progress has been made on pulp regeneration via cell homing strategies. This review focused on the requisite preconditions and cell homing strategies for pulp regeneration. In addition to the traditionally used mechanical preparation and irrigation, antibiotics, irrigation assisted with EndoVac apical negative-pressure system, and ultrasonic and laser irradiation are now being used in root canal disinfection. In addition, pulp-like tissues could be formed with the apical foramen less than 1 mm, although more studies are needed to determine the appropriate size. Moreover, signaling molecules including stromal cell derived factor (SDF-1α, basic Fibroblast Growth Factor (bFGF, Platelet Derived Growth Factor (PDGF, stem cell factor (SCF, and Granulocyte Colony-Stimulating Factor (G-CSF were used to achieve pulp-like tissue formation via a cell homing strategy. Studies on the cell sources of pulp regeneration might give some indications on the signaling molecular selection. The active recruitment of endogenous cells into root canals to regenerate pulp-like tissues is a novel concept that may offer an unprecedented opportunity for the near-term clinical translation of current biology-based therapies for dental pulp regeneration.

  2. Pulp Regeneration: Current Approaches and Future Challenges.

    Science.gov (United States)

    Yang, Jingwen; Yuan, Guohua; Chen, Zhi

    2016-01-01

    Regenerative endodontics aims to replace inflamed/necrotic pulp tissues with regenerated pulp-like tissues to revitalize teeth and improve life quality. Pulp revascularization case reports, which showed successful clinical and radiographic outcomes, indicated the possible clinical application of pulp regeneration via cell homing strategy. From a clinical point of view, functional pulp-like tissues should be regenerated with the characterization of vascularization, re-innervation, and dentin deposition with a regulated rate similar to that of normal pulp. Efficient root canal disinfection and proper size of the apical foramen are the two requisite preconditions for pulp regeneration. Progress has been made on pulp regeneration via cell homing strategies. This review focused on the requisite preconditions and cell homing strategies for pulp regeneration. In addition to the traditionally used mechanical preparation and irrigation, antibiotics, irrigation assisted with EndoVac apical negative-pressure system, and ultrasonic and laser irradiation are now being used in root canal disinfection. In addition, pulp-like tissues could be formed with the apical foramen less than 1 mm, although more studies are needed to determine the appropriate size. Moreover, signaling molecules including stromal cell derived factor (SDF-1α), basic Fibroblast Growth Factor (bFGF), Platelet Derived Growth Factor (PDGF), stem cell factor (SCF), and Granulocyte Colony-Stimulating Factor (G-CSF) were used to achieve pulp-like tissue formation via a cell homing strategy. Studies on the cell sources of pulp regeneration might give some indications on the signaling molecular selection. The active recruitment of endogenous cells into root canals to regenerate pulp-like tissues is a novel concept that may offer an unprecedented opportunity for the near-term clinical translation of current biology-based therapies for dental pulp regeneration.

  3. Pulp Regeneration: Current Approaches and Future Challenges

    Science.gov (United States)

    Yang, Jingwen; Yuan, Guohua; Chen, Zhi

    2016-01-01

    Regenerative endodontics aims to replace inflamed/necrotic pulp tissues with regenerated pulp-like tissues to revitalize teeth and improve life quality. Pulp revascularization case reports, which showed successful clinical and radiographic outcomes, indicated the possible clinical application of pulp regeneration via cell homing strategy. From a clinical point of view, functional pulp-like tissues should be regenerated with the characterization of vascularization, re-innervation, and dentin deposition with a regulated rate similar to that of normal pulp. Efficient root canal disinfection and proper size of the apical foramen are the two requisite preconditions for pulp regeneration. Progress has been made on pulp regeneration via cell homing strategies. This review focused on the requisite preconditions and cell homing strategies for pulp regeneration. In addition to the traditionally used mechanical preparation and irrigation, antibiotics, irrigation assisted with EndoVac apical negative-pressure system, and ultrasonic and laser irradiation are now being used in root canal disinfection. In addition, pulp-like tissues could be formed with the apical foramen less than 1 mm, although more studies are needed to determine the appropriate size. Moreover, signaling molecules including stromal cell derived factor (SDF-1α), basic Fibroblast Growth Factor (bFGF), Platelet Derived Growth Factor (PDGF), stem cell factor (SCF), and Granulocyte Colony-Stimulating Factor (G-CSF) were used to achieve pulp-like tissue formation via a cell homing strategy. Studies on the cell sources of pulp regeneration might give some indications on the signaling molecular selection. The active recruitment of endogenous cells into root canals to regenerate pulp-like tissues is a novel concept that may offer an unprecedented opportunity for the near-term clinical translation of current biology-based therapies for dental pulp regeneration. PMID:27014076

  4. An information theoretic approach for combining neural network process models.

    Science.gov (United States)

    Sridhar, D V.; Bartlett, E B.; Seagrave, R C.

    1999-07-01

    Typically neural network modelers in chemical engineering focus on identifying and using a single, hopefully optimal, neural network model. Using a single optimal model implicitly assumes that one neural network model can extract all the information available in a given data set and that the other candidate models are redundant. In general, there is no assurance that any individual model has extracted all relevant information from the data set. Recently, Wolpert (Neural Networks, 5(2), 241 (1992)) proposed the idea of stacked generalization to combine multiple models. Sridhar, Seagrave and Barlett (AIChE J., 42, 2529 (1996)) implemented the stacked generalization for neural network models by integrating multiple neural networks into an architecture known as stacked neural networks (SNNs). SNNs consist of a combination of the candidate neural networks and were shown to provide improved modeling of chemical processes. However, in Sridhar's work SNNs were limited to using a linear combination of artificial neural networks. While a linear combination is simple and easy to use, it can utilize only those model outputs that have a high linear correlation to the output. Models that are useful in a nonlinear sense are wasted if a linear combination is used. In this work we propose an information theoretic stacking (ITS) algorithm for combining neural network models. The ITS algorithm identifies and combines useful models regardless of the nature of their relationship to the actual output. The power of the ITS algorithm is demonstrated through three examples including application to a dynamic process modeling problem. The results obtained demonstrate that the SNNs developed using the ITS algorithm can achieve highly improved performance as compared to selecting and using a single hopefully optimal network or using SNNs based on a linear combination of neural networks.

  5. Region innovation and investment development: conceptual theoretical approach and business solutions

    Directory of Open Access Journals (Sweden)

    Zozulya D.M.

    2017-01-01

    Full Text Available The article describes essential problems of the region business innovation and investment development under current conditions, issues of crisis restrictions negotiation and innovation-driven economy formation. The relevance of the research is defined by the need of effective tools creation for business innovation and investment development and support, which can be applied, first, to increase efficiency of the region industrial activity, then improve production competitiveness on the innovative basis, overcome existing problems and provide sustainable innovation development in the region. The results of conducted research are represented in the article including region innovation and investment development concept model made up by the authors on the basis of system theoretical approach. The tools of the region innovation development defined in the concept model are briefly reviewed in the article. The most important of them include engineering marketing (marketing of scientific and technical innovations, strategic planning, benchmarking, place marketing and business process modeling.

  6. Theoretical approaches to creation of robotic coal mines based on the synthesis of simulation technologies

    Science.gov (United States)

    Fryanov, V. N.; Pavlova, L. D.; Temlyantsev, M. V.

    2017-09-01

    Methodological approaches to theoretical substantiation of the structure and parameters of robotic coal mines are outlined. The results of mathematical and numerical modeling revealed the features of manifestation of geomechanical and gas dynamic processes in the conditions of robotic mines. Technological solutions for the design and manufacture of technical means for robotic mine are adopted using the method of economic and mathematical modeling and in accordance with the current regulatory documents. For a comparative performance evaluation of technological schemes of traditional and robotic mines, methods of cognitive modeling and matrix search for subsystem elements in the synthesis of a complex geotechnological system are applied. It is substantiated that the process of technical re-equipment of a traditional mine with a phased transition to a robotic mine will reduce unit costs by almost 1.5 times with a significant social effect due to a reduction in the number of personnel engaged in hazardous work.

  7. Theoretical Triangulation as an Approach for Revealing the Complexity of a Classroom Discussion

    Science.gov (United States)

    van Drie, Jannet; Dekker, Rijkje

    2013-01-01

    In this paper we explore the value of theoretical triangulation as a methodological approach for the analysis of classroom interaction. We analyze an excerpt of a whole-class discussion in history from three theoretical perspectives: interactivity of the discourse, conceptual level raising and historical reasoning. We conclude that using…

  8. Theoretical Triangulation as an Approach for Revealing the Complexity of a Classroom Discussion

    Science.gov (United States)

    van Drie, Jannet; Dekker, Rijkje

    2013-01-01

    In this paper we explore the value of theoretical triangulation as a methodological approach for the analysis of classroom interaction. We analyze an excerpt of a whole-class discussion in history from three theoretical perspectives: interactivity of the discourse, conceptual level raising and historical reasoning. We conclude that using…

  9. From DNA radiation damage to cell death: theoretical approaches.

    Science.gov (United States)

    Ballarini, Francesca

    2010-10-05

    Some representative models of radiation-induced cell death, which is a crucial endpoint in radiobiology, were reviewed. The basic assumptions were identified, their consequences on predicted cell survival were analyzed, and the advantages and drawbacks of each approach were outlined. In addition to "historical" approaches such as the Target Theory, the Linear-Quadratic model, the Theory of Dual Radiation Action and Katz' model, the more recent Local Effect Model was discussed, focusing on its application in Carbon-ion hadrontherapy. Furthermore, a mechanistic model developed at the University of Pavia and based on the relationship between cell inactivation and chromosome aberrations was presented, together with recent results; the good agreement between model predictions and literature experimental data on different radiation types (photons, protons, alpha particles, and Carbon ions) supported the idea that asymmetric chromosome aberrations like dicentrics and rings play a fundamental role for cell death. Basing on these results, a reinterpretation of the TDRA was also proposed, identifying the TDRA "sublesions" and "lesions" as clustered DNA double-strand breaks and (lethal) chromosome aberrations, respectively.

  10. From DNA Radiation Damage to Cell Death: Theoretical Approaches

    Directory of Open Access Journals (Sweden)

    Francesca Ballarini

    2010-01-01

    Full Text Available Some representative models of radiation-induced cell death, which is a crucial endpoint in radiobiology, were reviewed. The basic assumptions were identified, their consequences on predicted cell survival were analyzed, and the advantages and drawbacks of each approach were outlined. In addition to “historical” approaches such as the Target Theory, the Linear-Quadratic model, the Theory of Dual Radiation Action and Katz' model, the more recent Local Effect Model was discussed, focusing on its application in Carbon-ion hadrontherapy. Furthermore, a mechanistic model developed at the University of Pavia and based on the relationship between cell inactivation and chromosome aberrations was presented, together with recent results; the good agreement between model predictions and literature experimental data on different radiation types (photons, protons, alpha particles, and Carbon ions supported the idea that asymmetric chromosome aberrations like dicentrics and rings play a fundamental role for cell death. Basing on these results, a reinterpretation of the TDRA was also proposed, identifying the TDRA “sublesions” and “lesions” as clustered DNA double-strand breaks and (lethal chromosome aberrations, respectively.

  11. Filter Feeding Mechanism Simulated Machine Paradigms – A Theoretical Approach

    Directory of Open Access Journals (Sweden)

    Channaveerappa. H,

    2014-01-01

    Full Text Available Bionics is the emerging branch of bio engineering where in the structures and functions of organism are utilized to construct a gadget that resembles the structure and performs similar function. The functional principles are also used to construct special gadgets to perform functions in the form of simulated robots. Animal models have also been used in creation of many structures/machines, for example the organization and flight mechanism of birds, echolocation in bats, and internal ear of mammals have been taken as blue prints to design aero planes, radars and telegraphic systems respectively. Here we are using ciliary feeding mechanisms in animals to create a machine that can be used for a particular purpose. Cilia are minute finger like protoplasmic extensions serve different functions like movement, creation of water current propelling and filter feeding in animals. In many invertebrates and lower chordates rotor movements of cilia create whirl pool of water current to obtain food material. Animals those use cilia for feeding are referred to ciliary feeders or filter feeders. The filter feeders are highly diverse in their habit but share common requirements. The filter feeders may be sessile or free swimming forms but the principles of feeding remains the same. In lower chordates the pharngometry of pharynx plays a decisive role in filter feeding. The filter feeding mechanism is highly evolved in animals through well designed evolutionary paradigms.

  12. Theoretical approach to calculation of transmission open access fee; Sodensen access ryokin santei no rironteki approach

    Energy Technology Data Exchange (ETDEWEB)

    Tsukamoto, T.; Sagawa, N. [The Institute of Energy Economics, Tokyo (Japan)

    1996-02-01

    In order to optimize introduction of wide area power transmission access according to the amended Electric Power Business Law, discussions were given on a theoretical approach to calculation of access fee to transmission lines. The amended law is intended not to limit new comers in power generation area to operations in the supply areas for general electric power business operators, but to form power wholesale markets in wider range. Since a power wholesale market is structured via one transmission network, the access conditions for transmission lines largely govern the economic reasonability for new market comers. Too high access fee prevents high-efficiency power generation units from entering a market, thus not resulting in reduction in energy fees. Conversely, if the fee is too low, harmful effects will result in the system operation, such as entry of low-efficiency generation units. What maximizes economic gains and gives incentives to the system participants would be an operation by using a marginal expense approach, but a number of problems also exists. The overall expense distribution method is simple and easy to operate, but contains economic problems related to technical problems, fairness, and efficiency in the system operation. 5 refs., 5 figs., 1 tab.

  13. Comparison of experimental and theoretical reaction rail currents, rail voltages, and airgap fields for the linear induction motor research vehicle

    Science.gov (United States)

    Elliott, D. G.

    1977-01-01

    Measurements of reaction rail currents, reaction rail voltages, and airgap magnetic fields in tests of the Linear Induction Motor Research Vehicle (LIMRV) were compared with theoretical calculations from the mesh/matrix theory. It was found that the rail currents and magnetic fields predicted by the theory are within 20 percent of the measured currents and fields at most motor locations in most of the runs, but differ by as much as a factor of two in some cases. The most consistent difference is a higher experimental than theoretical magnetic field near the entrance of the motor and a lower experimental than theoretical magnetic field near the exit. The observed differences between the theoretical and experimental magnetic fields and currents do not account for the differences of as much as 26 percent between the theoretical and experimental thrusts.

  14. Consumer Perception of Competitiveness – Theoretical-Instrumental Approach

    Directory of Open Access Journals (Sweden)

    Duralia Oana

    2016-04-01

    Full Text Available Behaviorist economic approach has recorded a quantum leap in a relatively short period of time, as studying the relationship between consumer behavior and companies’ strategic decisions based on market competitiveness are no longer an unknown area. However, this issue remains actual in view of the fact that during the decision process of purchase, consumers do not always behave rationally, as they are the only ones who can appreciate if the offer of the company, in terms of range, quality, price and auxiliary services meet their needs or not. In this context, this paper aims to deepen the existing interconnection between the market decisions of the enterprise and consumer behavior, as measure standard for the competitiveness of a firm on a certain market.

  15. An information theoretic approach to the functional classification of neurons

    CERN Document Server

    Schneidman, E; Berry, M J; Schneidman, Elad; Bialek, William; Berry, Michael J.

    2002-01-01

    A population of neurons typically exhibits a broad diversity of responses to sensory inputs. The intuitive notion of functional classification is that cells can be clustered so that most of the diversity is captured in the identity of the clusters rather than by individuals within clusters. We show how this intuition can be made precise using information theory, without any need to introduce a metric on the space of stimuli or responses. Applied to the retinal ganglion cells of the salamander, this approach recovers classical results, but also provides clear evidence for subclasses beyond those identified previously. Further, we find that each of the ganglion cells is functionally unique, and that even within the same subclass only a few spikes are needed to reliably distinguish between cells.

  16. Group-theoretical approach to relativistic eikonal physics

    Energy Technology Data Exchange (ETDEWEB)

    Leon, J.; Quiros, M. (Instituto de Enstructura de la Materia, C.S.I.C., Madrid (Spain); Departamento de Matematica, Universidad Complutense, Campus de Alcala (Spain)); Ramirez Mittelbrunn, J. (Instituto de Estructura de la Materia, C.S.I.C., Madrid (Spain))

    1977-09-01

    A contraction of the Poincare group is performed leading to the eikonal approximation. Invariants, one-particle states, spinning particles and some interaction problems are studied with the following results: momenta of ultrarelativistic particles behave as lightlike, the little group being E/sub 2/, spin behaves as that of zero-mass particles, helicity being conserved in the presence of interactions. The full eikonal results are rederived for Green's functions, wave functions, etc. The way for computing corrections due to transverse momenta and spin-dependent interactions is outlined. A parallel analysis is made for the infinite-momentum frame, the similarities and differences between this formalism and the eikonal approach being disclosed.

  17. Theoretical Basis of the Psychoanalytic Approach to Psychotherapy of Autism

    Directory of Open Access Journals (Sweden)

    Aldo Spelic

    2015-02-01

    Full Text Available In the modern scientific and professional environment psychoanalytic psychotherapy is placed in the background regarding its possibilities in the treatment of autism. This position, expressed by the question of possibilities of its use in the therapy of autism, is identified by the author as a result of the existing dichotomy (‘splitting’ in ‘organic’ and ‘psychic’ concepts of its etiology. To overcome the above constraint the author, on the base of his twenty years of psychotherapeutic experiences with eight autistic children, suggests the possibility of developing such concept of autistic psychogenesis and based on it a therapeutic approach. In support of his therapeutic observations, in this article were used contributions of contemporary researches by intersubjectivists, whose results speak in favour of the thesis.

  18. Theoretical Approaches to the Spin Structure of the Proton

    Science.gov (United States)

    Gonzalez Hernandez, Jose Osvaldo

    Many aspects of the structure of the proton are still unknown. One of the most noticeable unanswered question is the one of spin, that is, how can the fundamental degrees of freedom, quarks and gluons, account for the spin of the parent proton? It is known that quarks and gluons carry not only intrinsic but also orbital angular momentum. These two, combined, should in principle should add up to the value 1/2, which characterizes the spin of the proton. The mechanism responsible for this it is yet to be understood. It is not even clear how to define or "separate" the orbital angular momentum from the intrinsic angular momentum of the constituent particles. In recent years, one promising approach to this puzzle known as the spin crisis, is the possibility of accessing the transverse structure of the proton by means of the so called Generalized Parton Distributions (GPDs). These functions appear in the description of exclusive scattering processes. Since GPDs cannot be calculated from first principles, they must be extracted based upon models and experimental data. This dissertation presents the development of a new flexible parametrization, based on a "Reggeized" diquark approach, for chiral-even GPDs. This model is then used to analyze the significance of the different GPDs in some Deeply Virtual Compton Scattering measurements from Jlab; the results from this analysis are extended to the kinematical region relevant at the HERMES experiment. Subsequently, the model is extended to chiral-odd GPDs. With the tool of this model in hand, a study of the flavor dependence of Dirac and Pauli form factors is conducted. The connections between GPDs and other distribution functions are addressed in the last chapter, in the context of Wigner Distributions and possible probabilistic interpretations.

  19. A theoretical approach of Asperger’s syndrome in children

    Directory of Open Access Journals (Sweden)

    Chrysoula Valamoutopoulou

    2010-07-01

    Full Text Available The Asperger’s Syndrome is reported in the pervasive developmental disorders and was categorized as a separate disorder, initially in the ICD‐10 (World Health Organization, 1992 and afterwards in the DSM‐IV (American Psychiatric Organization, 1994. The Asperger’s Syndrome is distinguished by a team of symptoms that concern the low output in the social interaction and the communication dexterities, as well as the increased stereotypical behavior in various activities and interests.Aim: The aim of this present study was the descriptive review of bibliography concerning the epidemiology, the differential diagnosis from the autism, the etiology, the diagnosis, the therapeutic approaches and the adaptation difficulty of the family environment, with regard to the investigation of the Asperger ’s syndrome.Material and method: In the present review, the methodology that was followed included specialized electronic research with regard to the Asperger’s syndrome in children, using special keywords.Results: The review of the bibliography showed that the individuals with Asperger’s syndrome experience really big difficulties in elementary social behaviors, as failure in the growth and creation of friendly relations or in the search of amusing activities with others. Also, they face difficulties in the comprehension of not verbal communication (body language and the other’s expressions, the attitudes of body and the eye contact.Conclusions: The precocious recognition of Asperger’ s syndrome is imperative, with final objective the continuous briefing and sensitization of all health professionals as well as the wider public toward this, under the prism of interdisciplinary approach.

  20. A theoretical approach to the re-suspension factor

    Directory of Open Access Journals (Sweden)

    Magnoni M.

    2012-04-01

    Full Text Available The atmospheric re-suspension of radionuclides is a well-known phenomenon that consists in the re-injection into the atmosphere of previously deposited radioactivity. The process is driven by the action of wind on surfaces and can act as an additional source of radiation exposure by inhalation, after the deposition has finished. It is thus defined as the re-suspension factor, a parameter K generally considered as a time depending function and defined as the ratio of Ca, the volumetric air activity concentration (Bq m−3 and I0 (Bq m−2, the radioactivity deposition at time zero. The re-suspension factor concept is very useful in radioprotection in order to estimate the inhalation of radionuclides re-suspended from contaminated surfaces when direct atmospheric measurements are lacking or difficult to perform. However, the choice of the proper values of K is usually not a simple task, being quite site-specific and related to the meteorological, géomorphologie and environmental characteristics of the area to be studied. Moreover, several investigations showed clearly that the values of K are a decreasing function of time. For that reason, K values span several orders of magnitude: typical values in the range 10−5–10−10 m−1 are reported in literature for different environmental conditions and time elapsed since the deposition event. The current available models for the re-suspension factor are based on empirical formulas whose parameters are highly site dependent and cannot easily be related to some physical quantity. In this paper a simple physical model for the re-suspension factor is proposed and tested with available environmental radioactivity data (137Cs, collected since 1986 (Chernobyl fallout. The new model not only allows a satisfactory description of the experimental data like even the current empirical models do, but it is also able to connect the K values to quantities with a physical meaning (such as, for example a diffusion

  1. Hybrid empirical--theoretical approach to modeling uranium adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Hull, Larry C.; Grossman, Christopher; Fjeld, Robert A.; Coates, John T.; Elzerman, Alan W

    2004-05-01

    An estimated 330 metric tons of U are buried in the radioactive waste Subsurface Disposal Area (SDA) at the Idaho National Engineering and Environmental Laboratory (INEEL). An assessment of U transport parameters is being performed to decrease the uncertainty in risk and dose predictions derived from computer simulations of U fate and transport to the underlying Snake River Plain Aquifer. Uranium adsorption isotherms were measured for 14 sediment samples collected from sedimentary interbeds underlying the SDA. The adsorption data were fit with a Freundlich isotherm. The Freundlich n parameter is statistically identical for all 14 sediment samples and the Freundlich K{sub f} parameter is correlated to sediment surface area (r{sup 2}=0.80). These findings suggest an efficient approach to material characterization and implementation of a spatially variable reactive transport model that requires only the measurement of sediment surface area. To expand the potential applicability of the measured isotherms, a model is derived from the empirical observations by incorporating concepts from surface complexation theory to account for the effects of solution chemistry. The resulting model is then used to predict the range of adsorption conditions to be expected in the vadose zone at the SDA based on the range in measured pore water chemistry. Adsorption in the deep vadose zone is predicted to be stronger than in near-surface sediments because the total dissolved carbonate decreases with depth.

  2. A game-theoretic approach to valuating toxoplasmosis vaccination strategies.

    Science.gov (United States)

    Sykes, David; Rychtář, Jan

    2015-11-01

    The protozoan Toxoplasma gondii is a parasite often found in wild and domestic cats, and it is the cause of the disease toxoplasmosis. More than 60 million people in the United States carry the parasite, and the Centers for Disease Control have placed toxoplasmosis in their disease classification group Neglected Parasitic Infections as one of five parasitic diseases targeted as priorities for public health action. In recent years, there has been significant progress toward the development of a practical vaccine, so vaccination programs may soon be a viable approach to controlling the disease. Anticipating the availability of a toxoplasmosis vaccine, we are interested in determining when cat owners should vaccinate their own pets. We have created a mathematical model describing the conditions under which vaccination is advantageous. Our model can be used to predict the average vaccination level in the population. We find that there is a critical vaccine cost threshold above which no one will use the vaccine. A vaccine cost slightly below this threshold, however, results in high usage of the vaccine, and consequently in a significant reduction in population seroprevalence. Not surprisingly, we find that populations may achieve herd immunity only if the cost of vaccine is zero.

  3. Theoretical Aspects and Methodological Approaches to Sales Services Quality Assessment

    Directory of Open Access Journals (Sweden)

    Tarasova EE

    2015-11-01

    Full Text Available The article defines trade service quality and proposes an object-oriented approach for its essence interpretation, according to which such components as product offering and goods quality, service forms and goods selling methods, merchandising, services and staff are singled out; a model of managing retail outlets trading service, which covers levels of strategic, tactical and operational management and is aimed at ensuring customers’ perception expectations, achieving sustainable competitive positions and increasing customers’ loyalty is worked out; a methodology of trade services quality estimation that allows to carry out a comparative assessment of cooperative retailing both in terms of general indicators and their individual components, regulate the factors affecting trade services quality and have a positive administrative action is developed and tested; the results of evaluation of the customers’ service quality in the consumer cooperative retailers, dynamics of overall and comprehensive indicators of measurement of trade service quality for selected components are given; the main directions and measures for improving trade services quality basing on quantitative values of individual indicators for each of the five selected components (product offering and goods quality, service forms and sale methods, merchandising, services, staff are stated.

  4. Methods of quantifying operational risk in Banks : Theoretical approaches

    Directory of Open Access Journals (Sweden)

    Fatima Zahra El ARIF

    2016-07-01

    Full Text Available The definition of operational risk is a challenge. This risk has an atypical character as far as it concerns all the activities of the bank. It is also often difficult to estimate it independently of the other risks which characterizes the banking activity. Indeed, it is very difficult to determine the amount, the frequency, and the key factors behind this risk. Banks are still putting in place procedures of data collection and formalized approaches in this area. This is what we try to decipher. How then banks are they supposed to assess, predict and effectively manage operational risk, given the incredible diversity of dangers and threats now facing their business? How can they successfully respond to new constraints emanating from regulatory authorities while preserving their future profitability? These two questions are at the heart of the issues related to the measurement of operational risk, and are not without effect on the future ability of banks to manage this type of risk.

  5. Theoretical Approach to Predict the Performance of Thermoelectric Generator Modules

    Science.gov (United States)

    Elarusi, Abdulmunaem H.; Fagehi, Hassan; Lee, Hosung; Attar, Alaa

    2017-02-01

    The aim of this work was to examine the validity of the thermoelectric modules' performance predicted by formulating the effective thermoelectric material properties. The three maximum parameters (output power, current, and efficiency) are defined in terms of the average temperature of the thermoelectric generator (TEG). These three maximum parameters, which are either taken from commercial TEG modules or measurements for particular operating conditions, are used to define the effective material properties (Seebeck coefficient, thermal conductivity, and electrical resistivity). The commercial performance curves provided by the manufacturer were compared with the results obtained here by the effective material properties with the simple standard thermoelectric equations. It has been found that this technique predicts the performance of four commercial thermoelectric modules with fair to good accuracy. The characteristics of the TEGs were represented using the normalized charts constructed by formulating the parameters as a fraction of over the maximum parameters. The normalized charts would be universal for any given TEG module once the thermoelectric material is known.

  6. A Framework to Measure the Service Quality of Distributor with Fuzzy Graph Theoretic Approach

    Directory of Open Access Journals (Sweden)

    Tarun Kumar Gupta

    2016-01-01

    Full Text Available A combination of fuzzy logic and graph theoretic approach has been used to find the service quality of distributor in a manufacturing supply chain management. This combination is termed as the fuzzy graph theoretic (FGT approach. Initially the identified factors were grouped by SPSS (statistical package for social science software and then the digraph approach was applied. The interaction and inheritance values were calculated by fuzzy graph theory approach in terms of permanent function. Then a single numerical index was calculated by using permanent function which indicates the distributor service quality. This method can be used to compare the service quality of different distributors.

  7. Theoretical Grounds of Economic Assessment of the Current Level of Innovation Receptivity of Engineering Enterprises

    Directory of Open Access Journals (Sweden)

    Yemelianov Oleksandr Yu.

    2014-03-01

    Full Text Available The article studies and generalises existing approaches to identification of criteria of assessment of innovation receptivity of subjects of economic activity and also marks out main groups of methods of this assessment. It provides a chain of competences of an enterprise in the sphere of management of its innovation activity, which meets its passive and active innovation receptivity, which lies in the foundation of formation of the multiplicative approach to assessment of the current level of innovation receptivity of an enterprise. The article offers complex qualitative and quantitative indicators of active and also passive innovation receptivity of an enterprise. Further studies of the issue of assessment of the current level of innovation receptivity of economic subjects require clarification of capabilities of a more complete consideration of influence of the obtained financial results from the enterprise innovation activity upon this level.

  8. A theoretical analysis of parity violation induced by neutral currents in atomic cesium

    Science.gov (United States)

    Bouchiat, C.; Piketty, C. A.; Pignon, D.

    1983-07-01

    In this paper we give a theoretical analysis of the parity violation phenomena in nS - n'S transitions in atomic cesium induced by the electron-nucleus neutral-current interaction. The actual observation of parity violation consists in the measurement of an interference between the p.v. electric dipole amplitude Elpv with the electric amplitude induced by a static electric field. Our theoretical work must then include a calculation of the diagonal and non-diagonal polarizabilities of the states of atomic cesium. We have used a one-electron model proposed by Norcross which incorporates some many-body effects like the electric screening induced by the core polarization in a semi-empirical way. Our calculated values of the diagonal and non-diagonal polarizabilities of the nS states are in good agreement with the existing measurements; this confirms the already well-established success of the model in predicting the radiative transitions in cesium. We present theoretical arguments supported by detailed numerical computations showing that the one-particle matrix element of the parity-violating electron-nucleus interaction and the parity-violating electric dipole amplitude Elpv itself weakly depend on the shape of the one-electron potential provided the binding energies of the valence states are reproduced accurately. Furthermore it turns out that because of a compensation mechanism, the parity-violating transition is induced by the radiation field outside the ion core region where the screening can be described simply in terms of the measurable cesium ion polarizability. Our results are then used to extract, from the Ecole Normale Supérieure experiment, a value of the weak charge Qw = -57.1 ± 9.4 (r.m.s. statistical deviation) ± 4.7 (systematic uncertainty). This number is to be compared with the prediction of the Weinberg-Salam model with electro-weak radiative corrections: Qw = -68.6 ± 3.0. A general discussion of the uncertainties of the atomic physics

  9. Estimation-theoretic approach to delayed decoding of predictively encoded video sequences.

    Science.gov (United States)

    Han, Jingning; Melkote, Vinay; Rose, Kenneth

    2013-03-01

    Current video coders employ predictive coding with motion compensation to exploit temporal redundancies in the signal. In particular, blocks along a motion trajectory are modeled as an auto-regressive (AR) process, and it is generally assumed that the prediction errors are temporally independent and approximate the innovations of this process. Thus, zero-delay encoding and decoding is considered efficient. This paper is premised on the largely ignored fact that these prediction errors are, in fact, temporally dependent due to quantization effects in the prediction loop. It presents an estimation-theoretic delayed decoding scheme, which exploits information from future frames to improve the reconstruction quality of the current frame. In contrast to the standard decoder that reproduces every block instantaneously once the corresponding quantization indices of residues are available, the proposed delayed decoder efficiently combines all accessible (including any future) information in an appropriately derived probability density function, to obtain the optimal delayed reconstruction per transform coefficient. Experiments demonstrate significant gains over the standard decoder. Requisite information about the source AR model is estimated in a spatio-temporally adaptive manner from a bit-stream conforming to the H.264/AVC standard, i.e., no side information needs to be sent to the decoder in order to employ the proposed approach, thereby compatibility with the standard syntax and existing encoders is retained.

  10. Modeling the economic impact of medication adherence in type 2 diabetes: a theoretical approach

    Directory of Open Access Journals (Sweden)

    David S Cobden

    2010-08-01

    Full Text Available David S Cobden1, Louis W Niessen2, Frans FH Rutten1, W Ken Redekop11Department of Health Policy and Management, Section of Health Economics – Medical Technology Assessment (HE-MTA, Erasmus MC, Erasmus University Rotterdam, The Netherlands; 2Department of International Health, Johns Hopkins University School of Public Health, Johns Hopkins Medical Institutions, Baltimore, MD, USAAims: While strong correlations exist between medication adherence and health economic outcomes in type 2 diabetes, current economic analyses do not adequately consider them. We propose a new approach to incorporate adherence in cost-effectiveness analysis.Methods: We describe a theoretical approach to incorporating the effect of adherence when estimating the long-term costs and effectiveness of an antidiabetic medication. This approach was applied in a Markov model which includes common diabetic health states. We compared two treatments using hypothetical patient cohorts: injectable insulin (IDM and oral (OAD medications. Two analyses were performed, one which ignored adherence (analysis 1 and one which incorporated it (analysis 2. Results from the two analyses were then compared to explore the extent to which adherence may impact incremental cost-effectiveness ratios.Results: In both analyses, IDM was more costly and more effective than OAD. When adherence was ignored, IDM generated an incremental cost-effectiveness of $12,097 per quality-adjusted life-year (QALY gained versus OAD. Incorporation of adherence resulted in a slightly higher ratio ($16,241/QALY. This increase was primarily due to better adherence with OAD than with IDM, and the higher direct medical costs for IDM.Conclusions: Incorporating medication adherence into economic analyses can meaningfully influence the estimated cost-effectiveness of type 2 diabetes treatments, and should therefore be ­considered in health care decision-making. Future work on the impact of adherence on health

  11. Advancing the theoretical foundation of the partially-averaged Navier-Stokes approach

    Science.gov (United States)

    Reyes, Dasia Ann

    The goal of this dissertation is to consolidate the theoretical foundation of variable-resolution (VR) methods in general and the partially-averaged Navier-Stokes (PANS) approach in particular. The accurate simulation of complex turbulent flows remains an outstanding challenge in modern computational fluid dynamics. High-fidelity approaches such as direct numerical simulations (DNS) and large-eddy simulation (LES) are not typically feasible for complex engineering simulations with current computational technologies. Low-fidelity approaches such as Reynolds-averaged Navier-Stokes (RANS), although widely used, are inherently inadequate for turbulent flows with complex flow features. VR bridging methods fill the gap between DNS and RANS by allowing a tunable degree of resolution ranging from RANS to DNS. While the utility of VR methods is well established, the mathematical foundations and physical characterization require further development. This dissertation focuses on the physical attributes of fluctuations in partially-resolved simulations of turbulence. The specific objectives are to: (i) establish a framework for assessing the physical fidelity of VR methods to examine PANS fluctuations; (ii) investigate PANS simulations subject to multiple resolution changes; (iii) examine turbulent transport closure modeling for partially-resolved fields; (iv) examine the effect of filter control parameters in the limit of spectral cut-off in the dissipative region; and (v) validate low-Reynolds number corrections with RANS for eventual implementation with PANS. While the validation methods are carried out in the context of PANS, they are considered appropriate for all VR bridging methods. The key findings of this dissertation are summarized as follows. The Kolmogorov hypotheses are suitably adapted to describe fluctuations of partially-resolved turbulence fields, and the PANS partially-resolved field is physically consistent with the adapted Kolmogorov hypotheses. PANS

  12. Theoretical Approach to the Radiance-to-Flux Conversion in the EarthCARE Mission Framework.

    OpenAIRE

    Doménech García, Carlos

    2008-01-01

    The research of the Thesis, Theoretical Approach to the Radiance-to-Flux Conversion in the EarthCARE Framework, is aimed at studying the instantaneous TOA radiance-to-flux conversion for the prospective Broad-Band Radiometer (BBR) on-board the EarthCARE (Earth Clouds Aerosols and Radiation Explorer) platform, through the development of theoretical angular distribution models based on the specific designing features of the instrument. The inversion procedure has been undertaken to obtain the a...

  13. Theoretical analysis of parity violation induced by neutral currents in atomic cesium

    Energy Technology Data Exchange (ETDEWEB)

    Bouchiat, C.; Piketty, C.A.; Pignon, D. (Ecole Normale Superieure, 75 - Paris (France). Lab. de Physique Theorique)

    1983-07-04

    In this paper we give a theoretical analysis of the parity violation phenomena in nS-n'S transitions in atomic cesium induced by the electron-nucleus neutral-current interaction. The actual observation of parity violation consists in the measurement of an interference between the p.v. electric dipole amplitude E/sub 1/sup(pv) with the electric amplitude induced by a static electric field. Our theoretical work must then include a calculation of the diagonal and non-diagonal polarizabilities of the states of atomic cesium. We have used a one-electron model proposed by Norcross which incorporates some many-body effects like the electric screening induced by the core polarization in a semi-empirical way. Our calculated values of the diagonal and non-diagonal polarizabilities of the nS states are in good agreement with the existing measurements; this confirms the already well-established success of the model in predicting the radiative transitions in cesium. We present theoretical arguments supported by detailed numerical computations showing that the one-particle matrix element of the parity-violating electron-nucleus interaction and the parity-violating electric dipole amplitude E/sub 1/sup(pv) itself weakly depend on the shape of the one-electron potential provided the binding energies of the valence states are reproduced accurately. Furthermore it turns out that because of a compensation mechanism, the parity-violating transition is induced by the radiation field outside the ion core region where the screening can be described simply in terms of the measurable cesium ion polarizability. Our results are then used to extract, from the Ecole Normale Superieure experiment, a value of the weak charge Qsub(w)= -57.1+-9.4 (r.m.s. statistical deviation) +-4.7 (systematic uncertainty). This number is to be compared with the prediction of the Weinberg-Salam model with electro-weak radiative corrections: Qsub(w)=-68.6+-3.0.

  14. The autonomous communities and the EU from a theoretical perspective: overcoming the existing approaches?

    Directory of Open Access Journals (Sweden)

    John Etherington

    2012-09-01

    Full Text Available This article discusses the theoretical lessons from the results of the research project into the reforms of CARUE (Conference for EU-Related Affairs, between the Spanish state and the autonomous communities. To that end, the article begins by explaining the theoretical and methodological premises on which our research is based, and then summarises the main findings of our research, paying particular attention to the question of whether or not these reforms have empowered the autonomous communities as political actors within the framework of European governance. Finally, the results are used to reflect back on the dominant theoretical approaches to European governance and the role played by the regions within it; the conclusion is that any theoretical model that seeks to successfully deal with these questions must be sensitive to different national traditions and must understand the importance of historical inertias.

  15. Game Theoretical Approaches for Transport-Aware Channel Selection in Cognitive Radio Networks

    Directory of Open Access Journals (Sweden)

    Chen Shih-Ho

    2010-01-01

    Full Text Available Effectively sharing channels among secondary users (SUs is one of the greatest challenges in cognitive radio network (CRN. In the past, many studies have proposed channel selection schemes at the physical or the MAC layer that allow SUs swiftly respond to the spectrum states. However, they may not lead to enhance performance due to slow response of the transport layer flow control mechanism. This paper presents a cross-layer design framework called Transport Aware Channel Selection (TACS scheme to optimize the transport throughput based on states, such as RTT and congestion window size, of TCP flow control mechanism. We formulate the TACS problem as two different game theoretic approaches: Selfish Spectrum Sharing Game (SSSG and Cooperative Spectrum Sharing Game (CSSG and present novel distributed heuristic algorithms to optimize TCP throughput. Computer simulations show that SSSG and CSSG could double the SUs throughput of current MAC-based scheme when primary users (PUs use their channel infrequently, and with up to 12% to 100% throughput increase when PUs are more active. The simulation results also illustrated that CSSG performs up to 20% better than SSSG in terms of the throughput.

  16. GRAPH THEORETICAL AND NETWORKS APPROACH FOR THE DEVELOPMENT OF A LEARNING MODEL – A CASE STUDY

    Directory of Open Access Journals (Sweden)

    PROF. DR. P. K. SRIMANI

    2012-08-01

    Full Text Available This paper deals with the graph theoretical approach for developing a framework for the Learning model used to optimise the Mathematical Pathway in children at the elementary level and verifying it by usingNetworks model. Data collected pertaining to the mathematical concepts a child needs to learn at elementary level [Class I to VII] is represented by using Concept Flow Graphs and are optimized by using graph theory techniques and algorithms by rearranging nodes as per the learning progression, partitioning the graphs into subgraphsto represent levels of learning, optimizing the sub-graphs using merging and elimination technique and identifying / marking the optional nodes. The design of the framework by using the graph theoretical approach is validated by the application of the Networks approach and this is used to design the Mathematical Pathwaydriver which is the core component of the Learning model. This approach is novel and the Learning model developed is highly accurate.

  17. A Balanced Theoretical and Empirical Approach for the Development of a Design Support Tool

    DEFF Research Database (Denmark)

    Jensen, Thomas Aakjær; Hansen, Claus Thorp

    1996-01-01

    The introduction of a new design support system may change the engineering designer's work situation. Therefore, it may not be possible to derive all the functionalities for a design support system from solely empirical studies of manual design work. Alternatively the design support system could...... be based on a assertion with a theoretical foundation, which then is verified through empirical studies. However, to develop a design support system, there is a need for a balanced theoretical and empirical approach.This paper presents the results from the first steps in the development of a design support...... system, indicating a proposal for how to balance a theoretical and empirical approach. The result of this research will be utilized in the development of a Designer's Workbench to support the synthesis activity in mechanical design....

  18. A Theoretical Approach to Financial Therapy: The Development of the Ford Financial Empowerment Model

    OpenAIRE

    Kristy L. Archuleta; Joyce A. Baptist; Megan R. Ford

    2012-01-01

    The purpose of this paper is to introduce an integrative approach to working with clients experiencing problems related to financial disempowerment. The multi-phase model integrates three theoretically-driven psychotherapy approaches, including cognitive behavioral, narrative, and Virginia Satir’s experiential therapies, and financial counseling techniques to increase one’s sense of financial empowerment. A case study is included to demonstrate the applicability and effectiveness of the model...

  19. Approaching the theoretical capacitance of graphene through copper foam integrated three-dimensional graphene networks

    DEFF Research Database (Denmark)

    Dey, Ramendra Sundar; Hjuler, Hans Aage; Chi, Qijin

    2015-01-01

    We report a facile and low-cost approach for the preparation of all-in-one supercapacitor electrodes using copper foam (CuF) integrated three-dimensional (3D) reduced graphene oxide (rGO) networks. The binderfree 3DrGO@CuF electrodes are capable of delivering high specific capacitance approaching...... the theoretical capacitance of graphene and exhibiting high charge–discharge cycling stability....

  20. A Theoretical Approach to Financial Therapy: The Development of the Ford Financial Empowerment Model

    OpenAIRE

    Kristy L. Archuleta; Joyce A. Baptist; Megan R. Ford

    2012-01-01

    The purpose of this paper is to introduce an integrative approach to working with clients experiencing problems related to financial disempowerment. The multi-phase model integrates three theoretically-driven psychotherapy approaches, including cognitive behavioral, narrative, and Virginia Satir’s experiential therapies, and financial counseling techniques to increase one’s sense of financial empowerment. A case study is included to demonstrate the applicability and effectiveness of the model...

  1. The influence of Coalition Formation on Idea Selection in Dispersed Teams: A Game Theoretic Approach

    NARCIS (Netherlands)

    Sie, Rory

    2009-01-01

    Sie, R. L. L. (2009). The influence of coalition formation on idea selection in dispersed teams: a game theoretic approach. Poster presentation at the Fourth European conference on Technology Enhanced Learning (EC-TEL 2009). September, 29-October, 2, 2009, Nice, France.

  2. Speaking Back to the Deficit Discourses: A Theoretical and Methodological Approach

    Science.gov (United States)

    Hogarth, Melitta

    2017-01-01

    The educational attainment of Aboriginal and Torres Strait Islander students is often presented within a deficit view. The need for Aboriginal and Torres Strait Islander researchers to challenge the societal norms is necessary to contribute to the struggle for self-determination. This paper presents a theoretical and methodological approach that…

  3. Metaphor Analysis as an Approach for Exploring Theoretical Concepts: The Case of Social Capital

    NARCIS (Netherlands)

    Andriessen, Daniel; Gubbins, Claire

    2009-01-01

    In many fields within management and organizational literature there is considerable debate and controversy about key theoretical concepts and their definitions and meanings. Systematic metaphor analysis can be a useful approach to study the underlying conceptualizations that give rise to these cont

  4. The Influence of Coalition Formation on Idea Selection in Dispersed Teams: A Game Theoretic Approach

    NARCIS (Netherlands)

    Sie, Rory; Bitter-Rijpkema, Marlies; Sloep, Peter

    2009-01-01

    Sie, R. L. L., Bitter-Rijpkema, M., & Sloep, P. B. (2009). The Influence of Coalition Formation on Idea Selection in Dispersed Teams: A Game Theoretic Approach. In U. Cress, V. Dimitrova & M. Specht (Eds.), Learning in the Synergy of Multiple Disciplines. Proceedings of the Fourth European Conferenc

  5. Understanding Older Adults' Physical Activity Behavior: A Multi-Theoretical Approach

    Science.gov (United States)

    Grodesky, Janene M.; Kosma, Maria; Solmon, Melinda A.

    2006-01-01

    Physical inactivity is a health issue with serious consequences for older adults. Investigating physical activity promotion within a multi-theoretical approach may increase the predictive strength of physical activity determinants and facilitate the development and implementation of effective interventions for older adults. This article examines…

  6. Cancer of the cervix: current management and new approaches.

    Science.gov (United States)

    Shivnani, Anand T; Rimel, B J; Schink, Julian; Small, William

    2006-11-01

    This article summarizes the current management of patients with newly diagnosed cervical cancer. The topics range from the management of early-stage disease to the phase III randomized studies that have established the current standard of care for patients with locally advanced cancer of the cervix. New approaches to combined-modality therapy with the goal of improving outcomes and decreasing complications are also described.

  7. Understanding uncertainty in seagrass injury recovery: an information-theoretic approach.

    Science.gov (United States)

    Uhrin, Amy V; Kenworthy, W Judson; Fonseca, Mark S

    2011-06-01

    Vessel groundings cause severe, persistent gaps in seagrass beds. Varying degrees of natural recovery have been observed for grounding injuries, limiting recovery prediction capabilities, and therefore, management's ability to focus restoration efforts where natural recovery is unlikely. To improve our capacity for predicting seagrass injury recovery, we used an information-theoretic approach to evaluate the relative contribution of specific injury attributes to the natural recovery of 30 seagrass groundings in Florida Keys National Marine Sanctuary, Florida, USA. Injury recovery was defined by three response variables examined independently: (1) initiation of seagrass colonization, (2) areal contraction, and (3) sediment in-filling. We used a global model and all possible subsets for four predictor variables: (1) injury age, (2) original injury volume, (3) original injury perimeter-to-area ratio, and (4) wave energy. Successional processes were underway for many injuries with fast-growing, opportunistic seagrass species contributing most to colonization. The majority of groundings that exhibited natural seagrass colonization also exhibited areal contraction and sediment in-filling. Injuries demonstrating colonization, contraction, and in-filling were on average older and smaller, and they had larger initial perimeter-to-area ratios. Wave energy was highest for colonizing injuries. The information-theoretic approach was unable to select a single "best" model for any response variable. For colonization and contraction, injury age had the highest relative importance as a predictor variable; wave energy appeared to be associated with second-order effects, such as sediment in-filling, which in turn, facilitated seagrass colonization. For sediment in-filling, volume and perimeter-to-area ratio had similar relative importance as predictor variables with age playing a lesser role than seen for colonization and contraction. Our findings confirm that these injuries

  8. Strategy for a Rock Mechanics Site Descriptive Model. Development and testing of the theoretical approach

    Energy Technology Data Exchange (ETDEWEB)

    Staub, Isabelle; Fredriksson, Anders; Outters, Nils [Golder Associates AB, Uppsala (Sweden)

    2002-05-01

    In the purpose of studying the possibilities of a Deep Repository for spent fuel, the Swedish Nuclear and Fuel Management Company (SKB) is currently planning for Site Investigations. Data collected from these Site Investigations are interpreted and analysed to achieve the full Site Description, which is built up of models from all the disciplines that are considered of importance for the Site Description. One of these models is the Rock Mechanical Descriptive Model,which would be developed for any site in hard crystalline rock, and is a combination and evaluation of the characterisation of rock mass by means of empirical relationships and a theoretical approach based on numerical modelling. The present report describes the theoretical approach. The characterisation of the mechanical properties of the rock mass, viewed as a unit consisting of intact rock and fractures, is achieved by numerical simulations with following input parameters: initial stresses, fracture geometry, distribution of rock mechanical properties, such as deformation and strength parameters, for the intact rock and for the fractures. The numerical modelling was performed with the two-dimensional code UDEC, and the rock block models were generated from 2D trace sections extracted from the 3D Discrete Fracture Network (DFN) model. Assumptions and uncertainties related to the set-up of the model are considered. The numerical model was set-up to simulate a plain strain-loading test. Different boundary conditions were applied on the model for simulating stress conditions (I) in the undisturbed rock mass, and (II) at the proximity of a tunnel. In order to assess the reliability of the model sensitivity analyses have been conducted on some rock block models for defining the dependency of mechanical properties to in situ stresses, the influence of boundary conditions, rock material and joint constitutive models used to simulate the behaviour of intact rock and fractures, domain size and anisotropy. To

  9. Current approaches for detection of carcinoma in situ testis

    DEFF Research Database (Denmark)

    Hoei-Hansen, Christina E; Olesen, Inge A; Jørgensen, Niels

    2007-01-01

    of carcinoma in situ (CIS). This review describes current possible approaches for the detection of CIS. At present, an open testicular biopsy is the only definitive way of establishing the presence of CIS. The tissue section should be of an adequate size, be properly fixed, and evaluation be supported...

  10. LIMITATIONS OF CURRENT APPROACHES FOR THE TREATMENT OF ACROMEGALY.

    Science.gov (United States)

    Shanik, Michael H

    2016-02-01

    Acromegaly is a rare disease characterized by hypersecretion of growth hormone (GH), typically from a benign pituitary somatotroph adenoma, that leads to subsequent hypersecretion of insulin-like growth factor 1 (IGF-1). Patients with acromegaly have an increased risk of mortality and progressive worsening of comorbidities. Surgery, medical therapy, and radiotherapy are currently available treatment approaches for patients with acromegaly, with overall therapeutic goals of lowering GH levels and achieving normal IGF-1 levels, reducing tumor size, improving comorbidities, and minimizing mortality risk. Although surgery can lead to biochemical remission in some patients with acromegaly, many patients will continue to have uncontrolled disease and require additional treatment. We reviewed recently published reports and present a summary of the safety and efficacy of current treatment modalities for patients with acromegaly. A substantial proportion of patients who receive medical therapy or radiotherapy will have persistently elevated GH and/or IGF-1. Because of the serious health consequences of continued elevation of GH and IGF-1, there is a need to improve therapeutic approaches to optimize biochemical control, particularly in high-need patient populations for whom current treatment options provide limited benefit. This review discusses current treatment options for patients with acromegaly, limitations associated with each treatment approach, and areas within the current treatment algorithm, as well as patient populations for which improved therapeutic options are needed. Novel agents in development were also highlighted, which have the potential to improve management of patients with uncontrolled or persistent acromegaly.

  11. Current Approaches for Diagnosis of Influenza Virus Infections in Humans

    Directory of Open Access Journals (Sweden)

    Sai Vikram Vemula

    2016-04-01

    Full Text Available Despite significant advancement in vaccine and virus research, influenza continues to be a major public health concern. Each year in the United States of America, influenza viruses are responsible for seasonal epidemics resulting in over 200,000 hospitalizations and 30,000–50,000 deaths. Accurate and early diagnosis of influenza viral infections are critical for rapid initiation of antiviral therapy to reduce influenza related morbidity and mortality both during seasonal epidemics and pandemics. Several different approaches are currently available for diagnosis of influenza infections in humans. These include viral isolation in cell culture, immunofluorescence assays, nucleic acid amplification tests, immunochromatography-based rapid diagnostic tests, etc. Newer diagnostic approaches are being developed to overcome the limitations associated with some of the conventional detection methods. This review discusses diagnostic approaches currently available for detection of influenza viruses in humans.

  12. A comprehensive theoretical, numerical and experimental approach for crack detection in power plant rotating machinery

    Science.gov (United States)

    Stoisser, C. M.; Audebert, S.

    2008-05-01

    In order to describe the state-of-the-art on cracked rotor related problems, the current work presents the comprehensive theoretical, numerical and experimental approach adopted by EDF for crack detection in power plant rotating machinery. The work mainly focuses on the theoretical cracked beam model developed in the past years by S. Andrieux and C. Varé and associates both numerical and experimental aspects related to the crack detection problem in either turboset or turbo pump units. The theoretical part consists of the derivation of a lumped cracked beam model from the three-dimensional formulation of the general problem of elasticity with unilateral contact conditions on the crack lips, valid for any shape and number of cracks in the beam section and extended to cracks not located in a cross-section. This leads to the assessment of the cracked beam rigidity as a function of the rotation angle, in case of pure bending load or bending plus shear load. In this way the function can be implemented in a 1D rotordynamics code. An extension of the cracked beam model taking into account the torsion behaviour is also proposed. It is based on the assumption of full adherence between crack lips, when the crack closes, and on an incremental formulation of deformation energy. An experimental validation has been carried out using different cracked samples, both in static and dynamic configurations, considering one or three elliptic cracks in the same cross-section and helix-shaped cracks. Concerning the static configuration, a good agreement between numerical and experimental results is found. It is shown to be equal to 1% maximal gap of the beam deflection. Concerning the dynamical analysis, the main well-known indicator 2× rev. bending vibration component at half critical speed is approximated at maximum by 18% near the crack position. Our experiments also allowed for the observation of the bending and torsion resonance frequency shifts determined by the extra

  13. Experimental and theoretical investigations on the singularity of the intensity factor of the current in high temperature superconductors

    Science.gov (United States)

    Zhang, Xingyi; Huang, Yi; Zhou, Jun; Zhou, Youhe

    2013-08-01

    This paper presents experimental and analytical investigations into the distribution of current around a through-edge crack located in an infinitely long cylindrical high temperature superconductor (HTS) on the basis of the Bean model. Current distributions around the crack in the HTS without deformation are obtained by a simple conformal mapping. It is shown that the current is singular at the tip of the crack. An intensity factor of the current is introduced to characterize the singularity, the order of which is equal to -1. Additionally, an experimental verification according to the trapped field distributions around the crack is carried out, and the experimental results show little difference with the theoretical analysis.

  14. A new current line division concept for the determination of the current distribution in electrochemical cells. Part I. Theoretical background of the “corner weakness” effect in electroforming

    Directory of Open Access Journals (Sweden)

    R. M. STEVANOVIC

    2000-12-01

    Full Text Available A new approach to the determination of the current distribution in electrochemical cells, the current line division concept, is introduced. The new concept, based on the basic equations of electrics and electrochemical kinetics, was employed for a theoretical explanation of the phenomenon known in electroforming as “corner weakness”. It was shown that this phenomenon depends on the kind of control of the deposition process, being the largest in the case of pure ohmic control and disappearing in the case of pure activation control.

  15. Current Therapeutic Strategies and Novel Approaches in Osteosarcoma

    Science.gov (United States)

    Ando, Kosei; Heymann, Marie-Françoise; Stresing, Verena; Mori, Kanji; Rédini, Françoise; Heymann, Dominique

    2013-01-01

    Osteosarcoma is the most frequent malignant primary bone tumor and a main cause of cancer-related death in children and adolescents. Although long-term survival in localized osteosarcoma has improved to about 60% during the 1960s and 1970s, long-term survival in both localized and metastatic osteosarcoma has stagnated in the past several decades. Thus, current conventional therapy consists of multi-agent chemotherapy, surgery and radiation, which is not fully adequate for osteosarcoma treatment. Innovative drugs and approaches are needed to further improve outcome in osteosarcoma patients. This review describes the current management of osteosarcoma as well as potential new therapies. PMID:24216993

  16. Current Therapeutic Strategies and Novel Approaches in Osteosarcoma

    Energy Technology Data Exchange (ETDEWEB)

    Ando, Kosei, E-mail: andokercgv@gmail.com [INSERM, UMR 957, 1 Rue Gaston Veil, 44035 Nantes (France); Physiopathologie de la Résorption Osseuse et Therapie des Tumeurs Osseuses Primitives, Université de Nantes, Nantes Atlantique Universités, 1 Rue Gaston Veil, 44035 Nantes (France); Equipe Labellisee Ligue 2012, Nantes, 44035 (France); Heymann, Marie-Françoise [INSERM, UMR 957, 1 Rue Gaston Veil, 44035 Nantes (France); Physiopathologie de la Résorption Osseuse et Therapie des Tumeurs Osseuses Primitives, Université de Nantes, Nantes Atlantique Universités, 1 Rue Gaston Veil, 44035 Nantes (France); Equipe Labellisee Ligue 2012, Nantes, 44035 (France); Nantes University Hospital, Nantes 44035 (France); Stresing, Verena [INSERM, UMR 957, 1 Rue Gaston Veil, 44035 Nantes (France); Physiopathologie de la Résorption Osseuse et Therapie des Tumeurs Osseuses Primitives, Université de Nantes, Nantes Atlantique Universités, 1 Rue Gaston Veil, 44035 Nantes (France); Nantes University Hospital, Nantes 44035 (France); Mori, Kanji [Department of Orthopaedic Surgery, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga 520-2192 (Japan); Rédini, Françoise; Heymann, Dominique [INSERM, UMR 957, 1 Rue Gaston Veil, 44035 Nantes (France); Physiopathologie de la Résorption Osseuse et Therapie des Tumeurs Osseuses Primitives, Université de Nantes, Nantes Atlantique Universités, 1 Rue Gaston Veil, 44035 Nantes (France); Equipe Labellisee Ligue 2012, Nantes, 44035 (France); Nantes University Hospital, Nantes 44035 (France)

    2013-05-24

    Osteosarcoma is the most frequent malignant primary bone tumor and a main cause of cancer-related death in children and adolescents. Although long-term survival in localized osteosarcoma has improved to about 60% during the 1960s and 1970s, long-term survival in both localized and metastatic osteosarcoma has stagnated in the past several decades. Thus, current conventional therapy consists of multi-agent chemotherapy, surgery and radiation, which is not fully adequate for osteosarcoma treatment. Innovative drugs and approaches are needed to further improve outcome in osteosarcoma patients. This review describes the current management of osteosarcoma as well as potential new therapies.

  17. An Information-Theoretic Approach to PMU Placement in Electric Power Systems

    CERN Document Server

    Li, Qiao; Weng, Yang; Negi, Rohit; Franchetti, Franz; Ilic, Marija D

    2012-01-01

    This paper presents an information-theoretic approach to address the phasor measurement unit (PMU) placement problem in electric power systems. Different from the conventional 'topological observability' based approaches, this paper advocates a much more refined, information-theoretic criterion, namely the mutual information (MI) between the PMU measurements and the power system states. The proposed MI criterion can not only include the full system observability as a special case, but also can rigorously model the remaining uncertainties in the power system states with PMU measurements, so as to generate highly informative PMU configurations. Further, the MI criterion can facilitate robust PMU placement by explicitly modeling probabilistic PMU outages. We propose a greedy PMU placement algorithm, and show that it achieves an approximation ratio of (1-1/e) for any PMU placement budget. We further show that the performance is the best that one can achieve in practice, in the sense that it is NP-hard to achieve ...

  18. Chiral lagrangian approach to exchange vector currents in nuclei

    CERN Document Server

    Park, T S; Rho, M; Park, Tae Sun; Min, Dong Pil; Rho, Mannque

    1995-01-01

    Exchange vector currents are calculated up to one-loop order (corresponding to next-to-next-to-leading order) in chiral perturbation theory. As an illustration of the power of the approach, we apply the formalism to the classic nuclear process n+p\\rightarrow d +\\gamma at thermal energy. The exchange current correction comes out to be (4.5 \\pm 0.3) \\% in amplitude giving a predicted cross section \\sigma= (334\\pm 3)\\ {\\mbox mb} in excellent agreement with the experimental value (334.2\\pm 0.5)\\ {\\mbox mb}. Together with the axial charge transitions computed previously, this result provides a strong support for the power of chiral Lagrangians in nuclear physics. As a by-product of our results, we suggest an open problem in the application of chiral Lagrangian approach to nuclear processes that has to do with giving a physical meaning to the short-range correlations that play an important role in nuclei.

  19. A Theoretical Assessment of the Formation of IT clusters in Kazakhstan: Approaches and Positive Effects

    OpenAIRE

    Anel A. Kireyeva

    2016-01-01

    Abstract The aim of this research is to develop new theoretical approaches of the formation of IT clusters in order to strengthen of trend of the innovative industrialization and competitiveness of the country. Keeping with the previous literature, this study determines by the novelty of the problem, concerning the formation of IT clusters, which can become a driving force of transformation due to the interaction, improving efficiency and introducing advanced technology. In this research,...

  20. Physical context for theoretical approaches to sediment transport magnitude-frequency analysis in alluvial channels

    Science.gov (United States)

    Sholtes, Joel; Werbylo, Kevin; Bledsoe, Brian

    2014-10-01

    Theoretical approaches to magnitude-frequency analysis (MFA) of sediment transport in channels couple continuous flow probability density functions (PDFs) with power law flow-sediment transport relations (rating curves) to produce closed-form equations relating MFA metrics such as the effective discharge, Qeff, and fraction of sediment transported by discharges greater than Qeff, f+, to statistical moments of the flow PDF and rating curve parameters. These approaches have proven useful in understanding the theoretical drivers behind the magnitude and frequency of sediment transport. However, some of their basic assumptions and findings may not apply to natural rivers and streams with more complex flow-sediment transport relationships or management and design scenarios, which have finite time horizons. We use simple numerical experiments to test the validity of theoretical MFA approaches in predicting the magnitude and frequency of sediment transport. Median values of Qeff and f+ generated from repeated, synthetic, finite flow series diverge from those produced with theoretical approaches using the same underlying flow PDF. The closed-form relation for f+ is a monotonically increasing function of flow variance. However, using finite flow series, we find that f+ increases with flow variance to a threshold that increases with flow record length. By introducing a sediment entrainment threshold, we present a physical mechanism for the observed diverging relationship between Qeff and flow variance in fine and coarse-bed channels. Our work shows that through complex and threshold-driven relationships sediment transport mode, channel morphology, flow variance, and flow record length all interact to influence estimates of what flow frequencies are most responsible for transporting sediment in alluvial channels.

  1. Theoretical approaches to the problem of expertise of pacifist convictions of conscripts

    OpenAIRE

    Stvolygin K.V.

    2012-01-01

    The aim of this contribution is the analysis of theoretical approaches to the problem of carrying out the psychological expertise of pacifist convictions of persons subject to call to military service. Legalization of alternative civil service in the Russian Federation and other CIS states makes relevant the problem of verification of pacifist convictions, because it inevitably leads to questionable cases related to making statements of existence or lack of sincere convictions which are incom...

  2. Cognitive enrichment and welfare: Current approaches and future directions

    Directory of Open Access Journals (Sweden)

    Fay E. Clark

    2017-02-01

    Full Text Available “Cognitive enrichment” is a subset of enrichment that has gained interest from researchers over the past decade, particularly those working in zoos. This review explores the forms of cognitive enrichment that have been attempted for laboratory, farmed and zoo animals with a focus on the latter, including various definitions, aims, and approaches. This review reveals the fundamental theoretical and practical problems associated with cognitive enrichment, leading to recommendations for further research in this field. Critically, more research is needed to elucidate what makes challenges appropriate for certain taxa, acknowledging that individual differences exist. Going forward, we should be prepared to incorporate more computer technology into cognitive tasks, and examine novel welfare indicators such as flow, competence, and agency.

  3. Comparative antioxidant status in freshwater fish Carassius auratus exposed to six current-use brominated flame retardants: A combined experimental and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Mingbao; Qu, Ruijuan; Wang, Chao; Wang, Liansheng; Wang, Zunyao, E-mail: wangzun315cn@163.com

    2013-09-15

    Highlights: •A combined experimental and theoretical approach was used for risk assessments of six BFRs in fish. •Oxidative stress biomarkers were measured for toxicity identification. •Toxicity order was proposed via the integrated biomarker response. •Theoretical calculations were performed to analyze the BFRs toxicity. -- Abstract: Decabromodiphenyl ether (BDE-209) and several non-polybrominated diphenyl ether (PBDE) brominated flame retardants (BFRs), such as tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCD), decabromodiphenyl ethane (DBDPE), hexabromobenzene (HBB) and pentabromotoluene (PBT), are persistent halogenated contaminants ubiquitously detected in aquatic systems. However, data on comparative toxicological effects of these BFRs are lacking for fish. In this study, a combined experimental and theoretical approach was used to compare and analyze the effects of these BFRs on biochemical biomarkers in liver of Carassius auratus injected intraperitoneally with different doses (10 and 100 mg/kg) for 7, 14 and 30 days. Oxidative stress was evoked evidently for the prolonged exposure, represented by the significantly altered indices (superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione, and malondialdehyde). The integrated biomarker response (IBR) index ranked biotoxicity as: PBT > HBB > HBCD > TBBPA > BDE-209 > DBDPE. Quantum chemical calculations (electronic parameters, frontier molecular orbitals, and Wiberg bond order) were performed for theoretical analysis. Notably, some descriptors were correlated with the toxicity order, probably implying the existence of a potential structure–activity relationship when more BFRs were included. Besides, theoretical calculations also provided some valuable information regarding the molecular characteristics and metabolic pathways of these current-use BFRs, which may facilitate the understanding on their environmental behavior and fate. Overall, this study adopted a combined

  4. Quantitative photoacoustic assessment of red blood cell aggregation under pulsatile blood flow: experimental and theoretical approaches

    Science.gov (United States)

    Bok, Tae-Hoon; Hysi, Eno; Kolios, Michael C.

    2017-03-01

    In the present paper, the optical wavelength dependence on the photoacoustic (PA) assessment of the pulsatile blood flow was investigated by means of the experimental and theoretical approaches analyzing PA radiofrequency spectral parameters such as the spectral slope (SS) and mid-band fit (MBF). For the experimental approach, the pulsatile flow of human whole blood at 60 bpm was imaged using the VevoLAZR system (40-MHz-linear-array probe, 700-900 nm illuminations). For the theoretical approach, a Monte Carlo simulation for the light transmit into a layered tissue phantom and a Green's function based method for the PA wave generation was implemented for illumination wavelengths of 700, 750, 800, 850 and 900 nm. The SS and MBF for the experimental results were compared to theoretical ones as a function of the illumination wavelength. The MBF increased with the optical wavelength in both theory and experiments. This was expected because the MBF is representative of the PA magnitude, and the PA signal from red blood cell (RBC) is dependent on the molar extinction coefficient of oxyhemoglobin. On the other hand, the SS decreased with the wavelength, even though the RBC size (absorber size which is related to the SS) cannot depend on the illumination wavelength. This conflicting result can be interpreted by means of the changes of the fluence pattern for different illumination wavelengths. The SS decrease with the increasing illumination wavelength should be further investigated.

  5. A game-theoretic approach to real-time system testing

    DEFF Research Database (Denmark)

    David, Alexandre; Larsen, Kim Guldstrand; Li, Shuhao

    2008-01-01

    This paper presents a game-theoretic approach to the testing of uncontrollable real-time systems. By modelling the systems with Timed I/O Game Automata and specifying the test purposes as Timed CTL formulas, we employ a recently developed timed game solver UPPAAL-TIGA to synthesize winning...... strategies, and then use these strategies to conduct black-box conformance testing of the systems. The testing process is proved to be sound and complete with respect to the given test purposes. Case study and preliminary experimental results indicate that this is a viable approach to uncontrollable timed...... system testing....

  6. Current nutritional approaches in managing autism spectrum disorder: A review.

    Science.gov (United States)

    Cekici, Hande; Sanlier, Nevin

    2017-08-01

    The link between nutrition and autism spectrum disorder (ASD), which is a complex developmental disorder manifesting itself in significant delays or deviation in interaction and communication, has provided a fresh point of view and signals that nutrition may have a role in the aetiology of ASD, as well as play an active role in treatment by alleviating symptoms. In this review study aimed at evaluating, with scientific and concrete proof, the current medical nutrition implementations on ASD, existing medical nutrition therapies have been addressed and their effects on ASD symptoms have been discussed in light of current research. We reviewed articles regarding the medical nutritional therapy of autism on current nutritional approaches selected from PubMed, Science Direct, EBSCO, and databases about autism and nutrition. The research put forward that in individuals with ASD, while gluten-free/casein-free and ketogenic diets, camel milk, curcumin, probiotics, and fermentable foods can play a role in alleviating ASD symptoms, consumption of sugar, additives, pesticides, genetically modified organisms, inorganic processed foods, and hard-to-digest starches may aggravate symptoms. Further prospective controlled trials with large sample sizes are needed before recommendations can be made regarding the ideal ASD diet. This review emphasizes the value of identifying current nutritional approaches specific to individuals with ASD and integrating their effects on symptoms to the conversation and presents suggestions for future research designed to identify medical nutrition therapies targeting this population to better understand the link between ASD and nutrition.

  7. Quantification of Uncertainties in Turbulence Modeling: A Comparison of Physics-Based and Random Matrix Theoretic Approaches

    CERN Document Server

    Wang, Jian-Xun; Xiao, Heng

    2016-01-01

    Numerical models based on Reynolds-Averaged Navier-Stokes (RANS) equations are widely used in engineering turbulence modeling. However, the RANS predictions have large model-form uncertainties for many complex flows. Quantification of these large uncertainties originating from the modeled Reynolds stresses has attracted attention in turbulence modeling community. Recently, a physics-based Bayesian framework for quantifying model-form uncertainties has been proposed with successful applications to several flows. Nonetheless, how to specify proper priors without introducing unwarranted, artificial information remains challenging to the current form of the physics-based approach. Another recently proposed method based on random matrix theory provides the prior distributions with the maximum entropy, which is an alternative for model-form uncertainty quantification in RANS simulations. In this work, we utilize the random matrix theoretic approach to assess and possibly improve the specification of priors used in ...

  8. Theoretical study of the source-drain current and gate leakage current to understand the graphene field-effect transistors.

    Science.gov (United States)

    Yu, Cui; Liu, Hongmei; Ni, Wenbin; Gao, Nengyue; Zhao, Jianwei; Zhang, Haoli

    2011-02-28

    We designed acene molecules attached to two semi-infinite metallic electrodes to explore the source-drain current of graphene and the gate leakage current of the gate dielectric material in the field-effect transistors (FETs) device using the first-principles density functional theory combined with the non-equilibrium Green's function formalism. In the acene-based molecular junctions, we modify the connection position of the thiol group at one side, forming different electron transport routes. The electron transport routes besides the shortest one are defined as the cross channels. The simulation results indicate that electron transport through the cross channels is as efficient as that through the shortest one, since the conductance is weakly dependent on the distance. Thus, it is possible to connect the graphene with multiple leads, leading the graphene as a channel utilized in the graphene-based FETs in the mesoscopic system. When the conjugation of the cross channel is blocked, the junction conductance decreases dramatically. The differential conductance of the BA-1 is nearly 7 (54.57 μS) times as large as that of the BA-4 (7.35 μS) at zero bias. Therefore, the blocked graphene can be employed as the gate dielectric material in the top-gated graphene FET device, since the leakage current is small. The graphene-based field-effect transistors fabricated with a single layer of graphene as the channel and the blocked graphene as the gate dielectric material represent one way to overcome the problem of miniaturization which faces the new generation of transistors.

  9. A theoretical analysis to current exponent variation regularity and electromigration-induced failure

    Science.gov (United States)

    Wang, Yuexing; Yao, Yao

    2017-02-01

    The electric current exponent, typically with j-n form, is a key parameter to predict electromigration-induced failure lifetime. It is experimentally observed that the current exponent depends on different damage mechanisms. In the current research, the physical mechanisms including void initiation, void growth, and joule heating effect are all taken into account to investigate the current exponent variation regularity. Furthermore, a physically based model to predict the mean time to failure is developed and the traditional Black's equation is improved with clear physical meaning. It is found that the solution to the resulting void initiation and growth equation yields a current exponent of 2 and 1, respectively. On the other hand, joule heating plays an important role in failure time prediction and will induce the current exponent n > 2 based on the traditional semi-empirical model. The predictions are in agreement with the experimental results.

  10. Contravariant vs Covariant Quantum Logic: A Comparison of Two Topos-Theoretic Approaches to Quantum Theory

    CERN Document Server

    Wolters, Sander A M

    2010-01-01

    The aim of this paper is to compare the two topos-theoretic approaches to quantum mechanics that may be found in the literature to date. The first approach, which we will call the contravariant approach, was proposed by Isham and Butterfield, and was later extended by Doering and Isham. The second approach, which we will call the covariant approach, was developed by Heunen, Landsman and Spitters. Motivated by coarse-graining and the Kochen-Specker theorem, the contravariant approach uses the topos of presheaves on a specific context category, defined as the poset of commutative von Neumann subalgebras of some given von Neumann algebra. The intuitionistic logic of this approach is presented by the (complete) Heyting algebra of closed open subobjects of the so-called spectral presheaf. We demonstrate that in a natural way, this Heyting algebra defines a locale, internal to the given presheaf topos. This locale is not regular, which is connected to undesirable properties of the Heyting negation. In the covariant...

  11. Theoretical and Experimental Study of the Primary Current Distribution in Parallel-Plate Electrochemical Reactors

    Science.gov (United States)

    Vazquez Aranda, Armando I.; Henquin, Eduardo R.; Torres, Israel Rodriguez; Bisang, Jose M.

    2012-01-01

    A laboratory experiment is described to determine the primary current distribution in parallel-plate electrochemical reactors. The electrolyte is simulated by conductive paper and the electrodes are segmented to measure the current distribution. Experiments are reported with the electrolyte confined to the interelectrode gap, where the current…

  12. THEORETICAL INVESTIGATION ON BY-ONLY-CURRENT ELECTROMAGNETIC SEPARATION OF INCLUSION FROM MOLTEN METALS

    Institute of Scientific and Technical Information of China (English)

    B.W. Zhang; Z.M. Ren; Y.B. Zhong; K. Deng; K.D. Xu

    2002-01-01

    The electromagnetic field under applied AC and DC current in round and rectangularpipe was systematically investigated, then a concept of "equivalent current density"was proposed for evaluating the inhomogeneous electromagnetic pinch force, and themono-component removal efficiency and the overall removal efficiency of inclusionwere formulated. It is founded that flat pipe is superior to round pipe for the electro-magnetic removal of inclusion, and DC current can get a higher removal efficiencythan AC current due to absence of skin phenomenon. Under usual condition, a re-moval efficiency of 52% for 10μm inclusion or more than 92% for 20μm inclusioncan be achieved by imposing a current density of 3× 106A/m2 in a fiat pipe.

  13. From moral theory to penal attitudes and back: a theoretically integrated modeling approach.

    Science.gov (United States)

    de Keijser, Jan W; van der Leeden, Rien; Jackson, Janet L

    2002-01-01

    From a moral standpoint, we would expect the practice of punishment to reflect a solid and commonly shared legitimizing framework. Several moral legal theories explicitly aim to provide such frameworks. Based on the theories of Retributivism, Utilitarianism, and Restorative Justice, this article first sets out to develop a theoretically integrated model of penal attitudes and then explores the extent to which Dutch judges' attitudes to punishment fit the model. Results indicate that penal attitudes can be measured in a meaningful way that is consistent with an integrated approach to moral theory. The general structure of penal attitudes among Dutch judges suggests a streamlined and pragmatic approach to legal punishment that is identifiably founded on the separate concepts central to moral theories of punishment. While Restorative Justice is frequently presented as an alternative paradigm, results show it to be smoothly incorporated within the streamlined approach.

  14. Personalized medicine and treatment approaches in hypertension: current perspectives

    Directory of Open Access Journals (Sweden)

    Byrd JB

    2016-04-01

    Full Text Available James Brian Byrd Division of Cardiovascular Medicine, Department of Medicine, University of Michigan, Ann Arbor, MI, USA Abstract: In the US, hypertension affects one in three adults. Current guideline-based treatment of hypertension involves little diagnostic testing. A more personalized approach to the treatment of hypertension might be of use. Several methods of personalized treatment have been proposed and vetted to varying degrees. The purpose of this narrative review is to discuss the rationale for personalized therapy in hypertension, barriers to its development and implementation, some influential examples of proposed personalization measures, and a view of future efforts. Keywords: hypertension, blood pressure, personalized medicine

  15. Electrostatic discharge current linear approach and circuit design method

    Energy Technology Data Exchange (ETDEWEB)

    Katsivelis, P. K.; Fotis, G. P.; Gonos, I. F.; Koussiouris, T. G.; Stathopulos, I. A. [School of Electrical and Computer Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zographou 157 80, Athens (Greece)

    2010-11-15

    The electrostatic discharge (ESD) phenomenon is a great threat to all electronic devices and ICs. An electric charge passing rapidly from a charged body to another can seriously harm the last one. However, there is a lack in a linear mathematical approach which will make it possible to design a circuit capable of producing such a sophisticated current waveform. The commonly accepted electrostatic discharge current waveform is the one set by the IEC 61000-4-2. However, the over-simplified circuit included in the same standard is incapable of producing such a waveform. Treating the electrostatic discharge current waveform of the IEC 61000-4-2 as reference, an approximation method, based on Prony's method, is developed and applied in order to obtain a linear system's response. Considering a known input, a method to design a circuit, able to generate this ESD current waveform in presented. The circuit synthesis assumes ideal active elements. A simulation is carried out using the PSpice software. (authors)

  16. Progress in theoretical approach to InGaN and InN epitaxy: In incorporation efficiency and structural stability

    Science.gov (United States)

    Kangawa, Yoshihiro; Ito, Tomonori; Koukitu, Akinori; Kakimoto, Koichi

    2014-10-01

    The surface stability, growth process, and structural stability of InGaN and InN are reviewed from a theoretical viewpoint. In 2001, a new theoretical approach based on an ab initio calculation was developed. This theoretical approach enables the investigation of the influence of growth conditions such as partial pressure and temperature on the surface stability. The theoretical approach is applied to the research on the In incorporation efficiency in InGaN grown on nonpolar and semipolar surfaces. The calculation results suggest that the N-H layer formed on such surfaces has a crucial role in In incorporation. Moreover, the structural stability of InN grown by pressurized-reactor MOVPE is reviewed. It was found by the theoretical approach that \\{ 1\\bar{1}\\bar{1}\\} facet formation causes the spontaneous formation of islands with the zinc-blende structure.

  17. Generalized Field Theoretical Approach to General Relativity and Conserved Quantities in Anti-de Sitter Spacetimes

    CERN Document Server

    Pinto-Neto, N

    2000-01-01

    A new prescription to calculate the total energies and angular momenta of asymptotically $(d+1)$-dimensional anti-de Sitter spacetimes is proposed. The method is based on an extension of the field theoretical approach to General Relativity to the case where there is an effective cosmological constant. A $(d-1)$-form $\\Omega$ is exhibited which, when integrated on asymptotic $(d-1)$-dimensional boundary surfaces, yields the values of those conserved quantities. The calculations are gauge independent once asymptotic conditions are not violated . Total energies and angular momenta of some known solutions in four and five dimensions are calculated agreeing with standard results.

  18. Managing Knowledge by the Information System and Game-Theoretic Approach

    Directory of Open Access Journals (Sweden)

    Otilija Sedlak

    2006-12-01

    Full Text Available Knowledge is a source of competitive adventage. In small enterprises there is simultaneous cooperation and competition. Knowledge management research is focused on large firms. Collaboration among small enterprises and with large firms is common. Information systems and information technology play a paramount role in coordinating and controlling joint ventures. Information system is a key tool in the management of knowledge sharing. This paper offer game-theoretic approach to answer the questions under cooperation and competition: what to share, with whom, when, under what conditions is paramount, and the role of information system in managing knowledge in small enterprises.

  19. New approaches to business cycle theory in current economic science

    Directory of Open Access Journals (Sweden)

    Monica DOBRESCU

    2012-07-01

    Full Text Available In modern economies, current research generally acknowledges that the central issues in macroeconomics are essentially the same as those identified by Keynes in the General Theory of Employment, Interest and Money. One way or the other, economists are trying to address the same macroeconomic issues that they did seven decades ago: How can we account for the different growth rates and various fluctuations observed in national economies? Which are the economic policies most suitable to solve the issues of growth and cyclic behavior? Both the new classicals and the new Keynesians have made considerable progress within their research paradigms: to explain economic fluctuations, the new classicals focus on technological perturbations, the intertemporal substitution of leisure and real business cycles; on the other hand, the new Keynesians speak in terms of monopolistic competition, menu costs or efficiency wages. On the whole, the new classicals believe that the business cycle can best be understood within the market-clearing model, whereas the new keynesians believe that business fluctuations are due to certain market failures of various sorts.The present paper focuses on the main directions of research of the new classical school on the business cycle, given that the theoretical progress in this field has been significant and relevant for economic policy during the past four decades.

  20. A set-theoretic approach to linguistic feature structures and unification algorithms (I

    Directory of Open Access Journals (Sweden)

    N. Curteanu

    2000-10-01

    Full Text Available The paper proposes formal inductive definitions for linguistic feature structures (FSs taking values within a class of value types or sorts: single, disjunctive, (ordered lists, multisets (or bags, po-multisets (multisets embedded into a partially ordered set, and indexed (re-entrance values. The linguistic realization (semantics of the considered sorts is proposed. The FSs having these multi-sort values are organized as (rooted directed acyclic graphs. The concrete model of the FSs we had in mind for our set-theoretic definitions are the FSs used within the well-known HPSG linguistic theory. Set-theoretic general definitions for the proposed multi-sort FSs are defined. These constructive definitions start from atomic values and build recurrently multi-sorted values and structures, providing naturally a fixed-point semantics of the obtained FSs as a counterpart to the large class of logical semantics models on FSs. The linguistic unification algorithm based on tableau-subsumption is outlined. The Prolog code of the unification algorithm is provided and results of running it on some of the main multi-sort FSs is enclosed in the appendices. We consider the proposed formal approach to FS definitions and unification as necessary steps to set-theoretical implementations of natural language processing systems.

  1. A set-theoretic approach to linguistic feature structures and unification algorithms (II

    Directory of Open Access Journals (Sweden)

    N.Curteanu

    2001-02-01

    Full Text Available The paper proposes formal inductive definitions for linguistic feature structures (FSs taking values within a class of value types or sorts: single, disjunctive, (ordered lists, multisets (or bags, po-multisets (multisets embedded into a partially ordered set, and indexed (re-entrance values. The linguistic realization (semantics of the considered sorts is proposed. The FSs having these multi-sort values are organized as (rooted directed acyclic graphs. The concrete model of the FSs we had in mind for our set-theoretic definitions are the FSs used within the well-known HPSG linguistic theory. Set-theoretic general definitions for the proposed multi-sort FSs are defined. These constructive definitions start from atomic values and build recurrent multi-sorted values and structures, providing naturally a fixed-point semantics of the obtained FSs as a counterpart to the large class of logical semantics models on FSs. The linguistic unification algorithm based on tableau-subsumption is outlined. The Prolog code of the unification algorithm is provided and results of running it on some of the main multi-sort FSs is enclosed in the appendices. We consider the proposed formal approach to FSs definitions and unification as necessary steps to set-theoretical implementations of natural language processing systems.

  2. Current Approaches to the Establishment of Credit Risk Specific Provisions

    Directory of Open Access Journals (Sweden)

    Ion Nitu

    2008-10-01

    Full Text Available The aim of the new Basel II and IFRS approaches is to make the operations of financial institutions more transparent and thus to create a better basis for the market participants and supervisory authorities to acquire information and make decisions. In the banking sector, a continuous debate is being led, related to the similarities and differences between IFRS approach on loan loss provisions and Basel II approach on calculating the capital requirements, judging against the classical method regarding loan provisions, currently used by the Romanian banks following the Central Bank’s regulations.Banks must take into consideration that IFRS and Basel II objectives are fundamentally different. While IFRS aims to ensure that the financial papers reflect adequately the losses recorded at each balance sheet date, the Basel II objective is to ensure that the bank has enough provisions or capital in order to face expected losses in the next 12 months and eventual unexpected losses.Consequently, there are clear differences between the objectives of the two models. Basel II works on statistical modeling of expected losses while IFRS, although allowing statistical models, requires a trigger event to have occurred before they can be used. IAS 39 specifically states that losses that are expected as a result of future events, no matter how likely, are not recognized. This is a clear and fundamental area of difference between the two frameworks.

  3. Towards an Airframe Noise Prediction Methodology: Survey of Current Approaches

    Science.gov (United States)

    Farassat, Fereidoun; Casper, Jay H.

    2006-01-01

    In this paper, we present a critical survey of the current airframe noise (AFN) prediction methodologies. Four methodologies are recognized. These are the fully analytic method, CFD combined with the acoustic analogy, the semi-empirical method and fully numerical method. It is argued that for the immediate need of the aircraft industry, the semi-empirical method based on recent high quality acoustic database is the best available method. The method based on CFD and the Ffowcs William- Hawkings (FW-H) equation with penetrable data surface (FW-Hpds ) has advanced considerably and much experience has been gained in its use. However, more research is needed in the near future particularly in the area of turbulence simulation. The fully numerical method will take longer to reach maturity. Based on the current trends, it is predicted that this method will eventually develop into the method of choice. Both the turbulence simulation and propagation methods need to develop more for this method to become useful. Nonetheless, the authors propose that the method based on a combination of numerical and analytical techniques, e.g., CFD combined with FW-H equation, should also be worked on. In this effort, the current symbolic algebra software will allow more analytical approaches to be incorporated into AFN prediction methods.

  4. The Theoretical Approaches to Defining the Essence and Functions of Leasing

    Directory of Open Access Journals (Sweden)

    Levchenko Alexander A.

    2017-03-01

    Full Text Available The article is aimed at researching the theoretical foundations, generalizing scientific approaches to interpretation of the concept of «leasing», defining the main economic characteristics and functions of leasing. Scientific approaches of researchers to definition of the concept of «leasing» were systematized. New scientific approaches to interpretation of the concept of leasing as a form of public-private partnership, a form of ensuring competitiveness, have been allocated. The author’s own point of view on defining the economic essence of leasing as a special type of entrepreneurial activity which at the same time is implemented in the form of the credit-investment along with the trade-property relations has been substantiated. The main functions of leasing according to the object and subject approach in terms of outsourcing have been disclosed. Further researches in this direction will concern systematization of scientific approaches and definition of new attributes of the specific classification of leasing.

  5. Modified economic order quantity (EOQ model for items with imperfect quality: Game-theoretical approaches

    Directory of Open Access Journals (Sweden)

    Milad Elyasi

    2014-04-01

    Full Text Available In the recent decade, studying the economic order quantity (EOQ models with imperfect quality has appealed to many researchers. Only few papers are published discussing EOQ models with imperfect items in a supply chain. In this paper, a two-echelon decentralized supply chain consisting of a manufacture and a supplier that both face just in time (JIT inventory problem is considered. It is sought to find the optimal number of the shipments and the quantity of each shipment in a way that minimizes the both manufacturer’s and the supplier’s cost functions. To the authors’ best knowledge, this is the first paper that deals with imperfect items in a decentralized supply chain. Thereby, three different game theoretical solution approaches consisting of two non-cooperative games and a cooperative game are proposed. Comparing the results of three different scenarios with those of the centralized model, the conclusions are drawn to obtain the best approach.

  6. Towards Theoretical Approach to the Understanding of Language Ideologies in Post-Meiji Japan

    Directory of Open Access Journals (Sweden)

    Luka CULIBERG

    2011-05-01

    Full Text Available The paper wishes to examine the specific conditions that have generated the understanding of language in post-Meiji Japan and propose a theoretical approach to the question why a specific view on language, or to use a more precise concept – a language ideology, was, and still is, inevitable within a specific ideological horizon – the horizon of nationalism. In order to do so, it first gives an overview of the linguistic situation in post-Meiji Japan with all its competing and opposing views, following with an outline of the up to date research, its breakthroughs, its problems and its dead ends. Finally it proposes the orthodox method of dialectical materialism as a possibly only methodological approach hoping to grasp all these connected social problems in their totality.

  7. Theoretical approaches to holistic biological features: Pattern formation, neural networks and the brain-mind relation

    Indian Academy of Sciences (India)

    Alfred Gierer

    2002-06-01

    The topic of this article is the relation between bottom-up and top-down, reductionist and ``holistic” approaches to the solution of basic biological problems. While there is no doubt that the laws of physics apply to all events in space and time, including the domains of life, understanding biology depends not only on elucidating the role of the molecules involved, but, to an increasing extent, on systems theoretical approaches in diverse fields of the life sciences. Examples discussed in this article are the generation of spatial patterns in development by the interplay of autocatalysis and lateral inhibition; the evolution of integrating capabilities of the human brain, such as cognition-based empathy; and both neurobiological and epistemological aspects of scientific theories of consciousness and the mind.

  8. Theoretical and empirical approaches to using films as a means to increase communication efficiency.

    Directory of Open Access Journals (Sweden)

    Kiselnikova, N.V.

    2016-07-01

    Full Text Available The theoretical framework of this analytic study is based on studies in the field of film perception. Films are considered as a communicative system that is encrypted in an ordered series of shots, and decoding proceeds during perception. The shots are the elements of a cinematic message that must be “read” by viewer. The objective of this work is to analyze the existing theoretical approaches to using films in psychotherapy and education. An original approach to film therapy that is based on teaching clients to use new communicative sets and psychotherapeutic patterns through watching films is presented. The article specifies the main emphasized points in theories of film therapy and education. It considers the specifics of film therapy in the process of increasing the effectiveness of communication. It discusses the advantages and limitations of the proposed method. The contemporary forms of film therapy and the formats of cinema clubs are criticized. The theoretical assumptions and empirical research that could be used as a basis for a method of developing effective communication by means of films are discussed. Our studies demonstrate that the usage of film therapy must include an educational stage for more effective and stable results. This means teaching viewers how to recognize certain psychotherapeutic and communicative patterns in the material of films, to practice the skill of finding as many examples as possible for each pattern and to transfer the acquired schemes of analyzing and recognizing patterns into one’s own life circumstances. The four stages of the film therapeutic process as well as the effects that are achieved at each stage are described in detail. In conclusion, the conditions under which the usage of the film therapy method would be the most effective are observed. Various properties of client groups and psychotherapeutic scenarios for using the method of active film therapy are described.

  9. Mechanistic insight into degradation of endocrine disrupting chemical by hydroxyl radical: An experimental and theoretical approach.

    Science.gov (United States)

    Xiao, Ruiyang; Gao, Lingwei; Wei, Zongsu; Spinney, Richard; Luo, Shuang; Wang, Donghong; Dionysiou, Dionysios D; Tang, Chong-Jian; Yang, Weichun

    2017-09-13

    Advanced oxidation processes (AOPs) based on formation of free radicals at ambient temperature and pressure are effective for treating endocrine disrupting chemicals (EDCs) in waters. In this study, we systematically investigated the degradation kinetics of bisphenol A (BPA), a representative EDC by hydroxyl radical (OH) with a combination of experimental and theoretical approaches. The second-order rate constant (k) of BPA with OH was experimentally determined to be 7.2 ± 0.34 × 10(9) M(-1) s(-1) at pH 7.55. We also calculated the thermodynamic and kinetic behaviors for the bimolecular reactions by density functional theory (DFT) using the M05-2X method with 6-311++G** basis set and solvation model based on density (SMD). The results revealed that H-abstraction on the phenol group is the most favorable pathway for OH. The theoretical k value corrected by the Collins-Kimball approach was determined to be 1.03 × 10(10) M(-1) s(-1), which is in reasonable agreement with the experimental observation. These results are of fundamental and practical importance in understanding the chemical interactions between OH and BPA, and aid further AOPs design in treating EDCs during wastewater treatment processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. A set-theoretic approach for compensated signature embedding using projections onto convex sets

    Science.gov (United States)

    Ababneh, Sufyan; Ansari, Rashid; Khokhar, Ashfaq

    2008-01-01

    In this paper, we use a set-theoretic approach to provide an efficient and deterministic iterative solution for the compensated signature embedding (CSE) scheme introduced in an earlier work. 4 In CSE, a fragile signature is derived and embedded into the media using a robust watermarking technique. Since the embedding process leads to altering the media, the media samples are iteratively adjusted to compensate for the embedding distortion. Projections Onto Convex Sets (POCS) is an iterative set-theoretic approach known to be deterministic, effective and has been used in many image processing applications. We propose to use POCS for providing a compensation mechanism to address the CSE problem. We identify two convex constraint sets defined according to image fidelity and signature-generation criteria, and use them in a POCS-based CSE image authentication system. The system utilizes the wavelet transform domain for embedding and compensation. Simulation results are presented to show that the proposed scheme is efficient and accurate in terms of both achieving high convergence speed and maintaining image fidelity.

  11. A network-theoretic approach for decompositional translation across Open Biological Ontologies.

    Science.gov (United States)

    Patel, Chintan O; Cimino, James J

    2010-08-01

    Biological ontologies are now being widely used for annotation, sharing and retrieval of the biological data. Many of these ontologies are hosted under the umbrella of the Open Biological Ontologies Foundry. In order to support interterminology mapping, composite terms in these ontologies need to be translated into atomic or primitive terms in other, orthogonal ontologies, for example, gluconeogenesis (biological process term) to glucose (chemical ontology term). Identifying such decompositional ontology translations is a challenging problem. In this paper, we propose a network-theoretic approach based on the structure of the integrated OBO relationship graph. We use a network-theoretic measure, called the clustering coefficient, to find relevant atomic terms in the neighborhood of a composite term. By eliminating the existing GO to ChEBI Ontology mappings from OBO, we evaluate whether the proposed approach can re-identify the corresponding relationships. The results indicate that the network structure provides strong cues for decompositional ontology translation and the existing relationships can be used to identify new translations.

  12. Experiments and theoretical approaches on the burning behaviors of single n-heptane droplet

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Hyun Kyu [Kongju National University, Cheonan (Korea, Republic of)

    2015-05-15

    This study was conducted to improve the theoretical prediction of the burning characteristics of an n-heptane droplet by comparing them with experimental results. To achieve this, numerical approaches were conducted by assuming that the droplet combustion can be described by both quasi-steady behavior for the region between the droplet surface and the flame interface, and transient behavior for the region between the flame interface and ambient surrounding. Comparisons were considered for droplet diameter (d{sub t}), flame diameter (d{sub f}), flame standoff ratio (FSR), and viscous drag induced fluxes which are Stefan flux and thermophoretic flux for various initial droplet diameter (d{sub 0}) and oxygen (O{sub 2}) concentration conditions. It was revealed that the flame diameter (d{sub f}) and flame standoff ratio (FSR) initially increase dramatically and approach quasi-steady behavior within the observation period, and the flame standoff ratio (FSR) increases a little with the initial droplet diameter (d{sub 0}) both experimentally and theoretically. The value of flame diameter (d{sub f}) decreases from its maximum value when oxygen (O{sub 2}) concentration is increased from a value of 18% to 40%. The burning rate (K) constant becomes higher as the oxygen (O{sub 2}) concentration increases since the increase of oxygen (O{sub 2}) concentration produces a higher maximum flame temperature (T{sub f}) which enhances the effective thermo-physical properties of the gas-phase bounded by droplet and flame front.

  13. Synergies between Theoretical Approaches to Mathematics Education with Technology: A Case Study through a Cross-Analysis Methodology

    Science.gov (United States)

    Maracci, Mirko; Cazes, Claire; Vandebrouck, Fabrice; Mariotti, Maria Alessandra

    2013-01-01

    Mathematics education as a research domain is characterized by a plurality of theoretical approaches. Acknowledging the existence of such diversity and the risks of an excessive theoretical fragmentation does not mean to search for a unifying theory but to urge the community to develop strategies for coping with this diversity. This article is…

  14. Current and future prospects for the application of systematic theoretical methods to the study of problems in physical oceanography

    Science.gov (United States)

    Constantin, A.; Johnson, R. S.

    2016-09-01

    This essay is a commentary on the pivotal role of systematic theoretical methods in physical oceanography. At some level, there will always be a conflict between theory and experiment/data collection: Which is pre-eminent? Which should come first? This issue appears to be particularly marked in physical oceanography, to the extreme detriment of the development of the subject. It is our contention that the classical theory of fluids, coupled with methods from the theory of differential equations, can play a significant role in carrying the subject, and our understanding, forward. We outline the philosophy behind a systematic theoretical approach, highlighting some aspects of equatorial ocean dynamics where these methods have already been successful, paving the way for much more in the future and leading, we expect, to the better understanding of this and many other types of ocean flow. We believe that the ideas described here promise to reveal a rich and beautiful dynamical structure.

  15. A new theoretical model for transmembrane potential and ion currents induced in a spherical cell under low frequency electromagnetic field.

    Science.gov (United States)

    Zheng, Yu; Gao, Yang; Chen, Ruijuan; Wang, Huiquan; Dong, Lei; Dou, Junrong

    2016-10-01

    Time-varying electromagnetic fields (EMF) can induce some physiological effects in neuronal tissues, which have been explored in many applications such as transcranial magnetic stimulation. Although transmembrane potentials and induced currents have already been the subjects of many theoretical studies, most previous works about this topic are mainly completed by utilizing Maxwell's equations, often by solving a Laplace equation. In previous studies, cells were often considered to be three-compartment models with different electroconductivities in different regions (three compartments are often intracellular regions, membrane, and extracellular regions). However, models like that did not take dynamic ion channels into consideration. Therefore, one cannot obtain concrete ionic current changes such as potassium current change or sodium current change by these models. The aim of the present work is to present a new and more detailed model for calculating transmembrane potentials and ionic currents induced by time-varying EMF. Equations used in the present paper originate from Nernst-Plank equations, which are ionic current-related equations. The main work is to calculate ionic current changes induced by EMF exposure, and then transmembrane potential changes are calculated with Hodgkin-Huxley model. Bioelectromagnetics. 37:481-492, 2016. © 2016 Wiley Periodicals, Inc.

  16. A Theoretical Model of Pinching Current Sheet in Low-beta Plasmas

    CERN Document Server

    Takeshige, Satoshi; Shibata, Kazunari

    2015-01-01

    Magnetic reconnection is an important physical process in various explosive phenomena in the universe. In the previous studies, it was found that fast re- connection takes place when the thickness of a current sheet becomes on the order of a microscopic length such as the ion larmor radius or the ion inertial length. In this study, we investigated the pinching process of a current sheet by the Lorentz force in a low-{\\beta} plasma using one-dimensional magnetohydrodynam- ics (MHD) simulations. It is known that there is an exact self-similar solution for this problem that neglects gas pressure. We compared the non-linear MHD dynamics with the analytic self-similar solution. From the MHD simulations, we found that with the gas pressure included the implosion process deviates from the analytic self-similar solution as t {\\rightarrow} t 0, where t 0 is the explosion time when the thickness of a current sheet of the analytic solution becomes 0. We also found a pair of MHD fast-mode shocks are generated and propaga...

  17. Two complementary approaches to right-handed currents

    Energy Technology Data Exchange (ETDEWEB)

    Gemmler, Katrin M.

    2012-04-17

    Flavour observables impose strong constraints on models of new physics. We study whether right-handed currents can provide a realistic extension to the Standard Model. We analyse two complementary models. These setups lead to new flavour violating interactions in the right-handed sector. We first consider a bottom-up approach assuming a left-right symmetric flavour group broken only by the Yukawa couplings. In this model the vertical stroke V{sub ub} vertical stroke problem can be solved. Secondly we study the Left-Right Model. We perform a comprehensive numerical analysis, including all known experimental constraints from {Delta}F=2 observables and the decay B {yields}X{sub s}{gamma} simultaneously. We observe that there exist regions in parameter space in accordance with the all data. In this model all flavour anomalies can be resolved except the vertical stroke V{sub ub} vertical stroke problem.

  18. DIABETIC POLYNEUROPATHY: CURRENT APPROACHES TO DIAGNOSIS AND PATHOGENETIC THERAPY

    Directory of Open Access Journals (Sweden)

    O. S. Levin

    2013-01-01

    Full Text Available The paper considers the current views of the prevalence, clinical picture, approaches to the diagnosis and treatment of one of the most commonneurological complications of diabetes mellitus – diabetic polyneuropathy, and both its somatic and autonomous manifestations. Neuropathy ismost common in diabetic patients and its clinical forms reflect the severe course of diabetes mellitus and serve as an unfavorable prognostic signthat is associated with an approximately 5-fold increase in mortality. At the same time, the timely detection and adequate correction of the manifestations of neuropathy may substantially improve quality of life in the patients. The possibilities of pathogenetic therapy for diabetic polyneuropathy associated mainly with the use of benfotiamine and alpha-lipoic acid, as well as symptomatic therapy for its individual manifestationsare considered.

  19. A Theoretical Assessment of the Formation of IT clusters in Kazakhstan: Approaches and Positive Effects

    Directory of Open Access Journals (Sweden)

    Anel A. Kireyeva

    2016-04-01

    Full Text Available Abstract The aim of this research is to develop new theoretical approaches of the formation of IT clusters in order to strengthen of trend of the innovative industrialization and competitiveness of the country. Keeping with the previous literature, this study determines by the novelty of the problem, concerning the formation of IT clusters, which can become a driving force of transformation due to the interaction, improving efficiency and introducing advanced technology. In this research, we used conceptual approach employs the study of different conceptual views of scientists on a specific research object; structured approach involves determination of properties of a whole object by identifying the different relationships; system approach aims to develop research methods and design of complex objects – systems of different types. This study allows to conclude that IT-clusters will be most effective when they evolve naturally, originating under the action of internal forces of consolidation of  innovative, information and communications infrastructure (industrial parks, techno polis, research laboratories and business incubators, formation of soft infrastructure, that can help to find quick, innovative and creative ways to solve problems.

  20. Estimate of the theoretical uncertainty of the cross sections for nucleon knockout in neutral-current neutrino-oxygen interactions

    CERN Document Server

    Ankowski, Artur M; Benhar, Omar; Caballero, Juan A; Giusti, Carlotta; González-Jiménez, Raúl; Megias, Guillermo D; Meucci, Andrea

    2015-01-01

    Free nucleons propagating in water are known to produce gamma rays, which form a background to the searches for diffuse supernova neutrinos and sterile neutrinos carried out with Cherenkov detectors. As a consequence, the process of nucleon knockout induced by neutral-current quasielastic interactions of atmospheric (anti)neutrinos with oxygen needs to be under control at the quantitative level in the background simulations of the ongoing and future experiments. In this paper, we provide a quantitative assessment of the uncertainty associated with the theoretical description of the nuclear cross sections, estimating it from the discrepancies between the predictions of different models.

  1. Numerical Methods Application for Reinforced Concrete Elements-Theoretical Approach for Direct Stiffness Matrix Method

    Directory of Open Access Journals (Sweden)

    Sergiu Ciprian Catinas

    2015-07-01

    Full Text Available A detailed theoretical and practical investigation of the reinforced concrete elements is due to recent techniques and method that are implemented in the construction market. More over a theoretical study is a demand for a better and faster approach nowadays due to rapid development of the calculus technique. The paper above will present a study for implementing in a static calculus the direct stiffness matrix method in order capable to address phenomena related to different stages of loading, rapid change of cross section area and physical properties. The method is a demand due to the fact that in our days the FEM (Finite Element Method is the only alternative to such a calculus and FEM are considered as expensive methods from the time and calculus resources point of view. The main goal in such a method is to create the moment-curvature diagram in the cross section that is analyzed. The paper above will express some of the most important techniques and new ideas as well in order to create the moment curvature graphic in the cross sections considered.

  2. A game theoretic approach for interbasin water resources allocation considering the water quality issues.

    Science.gov (United States)

    Mahjouri, Najmeh; Ardestani, Mojtaba

    2010-08-01

    In this paper, a new game theoretic methodology is developed for interbasin water transfer management with regard to economic, equity, and environmental criteria. The main objective is to supply the competing users in a fair way, while the efficiency and environmental sustainability criteria are satisfied and the utilities of water users are incorporated. Firstly, an optimization model is developed to proportionally allocate water to the competing users in water donor and receiving basins based on their water demands. Secondly, for different coalitions of water users, the water shares of the coalitions are determined using an optimization model with economic objectives regarding the physical and environmental constraints of the system. In order to satisfy water-quality requirements, the impacts of decreasing the instream flow in donor basin are estimated using a water-quality simulation model, and the required treatment levels for effluents discharged into the river, downstream of the water transfer point are determined. Finally, to achieve equity and to provide sufficient incentives for water users to participate in the cooperation, some cooperative game theoretic approaches are utilized for reallocation of net benefits to water users. This model is applied to a large-scale interbasin water allocation problem including two different basins struggling with water scarcity in Iran. The results show that this model can be utilized as an effective tool for optimal interbasin water allocation management involving stakeholders with conflicting objectives subject to physical and environmental constraints.

  3. Regulation of cellular function via electromagnetic field frequency and extracellular environment: A theoretical- experimental approach

    Science.gov (United States)

    Taghian, Toloo; Sheikh, Abdul; Narmoneva, Daria; Kogan, Andrei

    2015-03-01

    Application of external electric field (EF) as a non-pharmacological, non-invasive tool to control cell function is of great therapeutic interest. We developed a theoretical-experimental approach to investigate the biophysical mechanisms of EF interaction with cells in electrode-free physiologically-relevant configuration. Our numerical results demonstrated that EF frequency is the major parameter to control cell response to EF. Non-oscillating or low-frequency EF leads to charge accumulation on the cell surface membrane that may mediate membrane initiated cell responses. In contrast, high-frequency EF penetrates the cell membrane and reaches cell cytoplasm, where it may directly activate intracellular responses. The theoretical predictions were confirmed in our experimental studies of the effects of applied EF on vascular cell function. Results show that non-oscillating EF increases vascular endothelial growth factor (VEGF) expression while field polarity controls cell adhesion rate. High-frequency, but not low frequency, EF provides differential regulation of cytoplasmic focal adhesion kinase and VEGF expression depending on the substrate, with increased expression in cells cultured on RGD-rich synthetic hydrogels, and decreased expression for matrigel culture. The authors acknowledge the financial support from the NSF (DMR-1206784 & DMR-0804199 to AK); the NIH (1R21 DK078814-01A1 to DN) and the University of Cincinnati (Interdisciplinary Faculty Research Support Grant to DN and AK).

  4. THEORETICAL APPROACHES TO THE ANALYSIS OF THE PROBLEM OF SEPARATION IN DOMESTIC AND FOREIGN PSYCHOLOGY

    Directory of Open Access Journals (Sweden)

    Lugovsky V. A.

    2016-05-01

    Full Text Available The article surveys the process of psychological separation from parents in the student's age. Relevance of the research topic is connected with the existing problems in the modern student environment, which include the general trends of the late maturation in adolescents (infantilization: extension of childhood, low achievement motivation, the lack of desire for selfdevelopment, unwillingness to take responsibility for their own lives. The importance of the theme is emphasized by a number of age problems. Without solving these problems, individual development is almost impossible. The authors give the analysis of the theoretical concepts of separation problems in the domestic and foreign psychology, examine the concept of separation in the context of different approaches to its study. Based on the research, the definition of separation is formulated. Separation individuation processes are discussed in the psychoanalytic direction, through the family system therapy, the study of the level of intergenerational relations in the dichotomy of "proximity - gap", the establishment of the sovereignty of the individual, the formation of psychological space. On the basis of the theoretical analysis the authors categorize the types of separation as contradictory or ambivalent, successful, crisis, conflict categorization and give the characteristics of each type and its impact on the resolution of the separation conflict

  5. A short course in quantum information theory. An approach from theoretical physics. 2. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Diosi, Lajos [KFKI Research Institute for Particle and Nuclear Physics (RMKI), Budapest (Hungary). MTA Budapest

    2011-07-01

    This short and concise primer takes the vantage point of theoretical physics and the unity of physics. It sets out to strip the burgeoning field of quantum information science to its basics by linking it to universal concepts in physics. An extensive lecture rather than a comprehensive textbook, this volume is based on courses delivered over several years to advanced undergraduate and beginning graduate students, but essentially it addresses anyone with a working knowledge of basic quantum physics. Readers will find these lectures a most adequate entry point for theoretical studies in this field. For the second edition, the authors has succeeded in adding many new topics while sticking to the conciseness of the overall approach. A new chapter on qubit thermodynamics has been added, while new sections and subsections have been incorporated in various chapter to deal with weak and time-continuous measurements, period-finding quantum algorithms and quantum error corrections. From the reviews of the first edition: ''The best things about this book are its brevity and clarity. In around 100 pages it provides a tutorial introduction to quantum information theory, including problems and solutions.. it's worth a look if you want to quickly get up to speed with the language and central concepts of quantum information theory, including the background classical information theory.'' (Craig Savage, Australian Physics, Vol. 44 (2), 2007). (orig.)

  6. NON-TERRITORIAL AUTONOMY IN RUSSIA: PRACTICAL IMPLICATIONS OF THEORETICAL APPROACHES

    Directory of Open Access Journals (Sweden)

    Tatiana RUDNEVA

    2012-06-01

    Full Text Available Despite the theoretical possibility to use non-territorial autonomy as a mechanism through which ethnic groups can fulfil their right to selfdetermination along with other minority rights, not many states have been willing to put theory into practice. The article offers an explanation why wider applicability of NTA is problematic by arguing that the theory itself is not yet polished enough to be implemented. The study includes examination of both theoretical approaches and empirical data from a case study of an attempt to establish NTAs in the Russian Federation. The findings suggest that inconsistencies and unclarities in the theory do correlate with practical flaws of NTAs, which allows to suggest that when the theory is tested empirically, the reality reveals all the flaws of the theory. The results indicate that the concept of NTA needs further refinement and development to make it more practice-oriented and applicable. As the problem of minority rights is still to be dealt with, we also propose a model of global union of NTAs where each ethnic group is represented by a non-governmental organisation, which seems to be more applicable than the others, alongside a number of other mechanisms that are even more essential and universal and focus on defending basic human rights

  7. Model-free information-theoretic approach to infer leadership in pairs of zebrafish

    Science.gov (United States)

    Butail, Sachit; Mwaffo, Violet; Porfiri, Maurizio

    2016-04-01

    Collective behavior affords several advantages to fish in avoiding predators, foraging, mating, and swimming. Although fish schools have been traditionally considered egalitarian superorganisms, a number of empirical observations suggest the emergence of leadership in gregarious groups. Detecting and classifying leader-follower relationships is central to elucidate the behavioral and physiological causes of leadership and understand its consequences. Here, we demonstrate an information-theoretic approach to infer leadership from positional data of fish swimming. In this framework, we measure social interactions between fish pairs through the mathematical construct of transfer entropy, which quantifies the predictive power of a time series to anticipate another, possibly coupled, time series. We focus on the zebrafish model organism, which is rapidly emerging as a species of choice in preclinical research for its genetic similarity to humans and reduced neurobiological complexity with respect to mammals. To overcome experimental confounds and generate test data sets on which we can thoroughly assess our approach, we adapt and calibrate a data-driven stochastic model of zebrafish motion for the simulation of a coupled dynamical system of zebrafish pairs. In this synthetic data set, the extent and direction of the coupling between the fish are systematically varied across a wide parameter range to demonstrate the accuracy and reliability of transfer entropy in inferring leadership. Our approach is expected to aid in the analysis of collective behavior, providing a data-driven perspective to understand social interactions.

  8. A theoretical validation of the B-matrix spatial distribution approach to diffusion tensor imaging.

    Science.gov (United States)

    Borkowski, Karol; Kłodowski, Krzysztof; Figiel, Henryk; Krzyżak, Artur Tadeusz

    2017-02-01

    The recently presented B-matrix Spatial Distribution (BSD) approach is a calibration technique which derives the actual distribution of the B-matrix in space. It is claimed that taking into account the spatial variability of the B-matrix improves the accuracy of diffusion tensor imaging (DTI). The purpose of this study is to verify this approach theoretically through computer simulations. Assuming three different spatial distributions of the B-matrix, diffusion weighted signals were calculated for the six orientations of a model anisotropic phantom. Subsequently two variants of the BSD calibration were performed for each of the three cases; one with the assumption of high uniformity of the model phantom (uBSD-DTI) and the other taking into account imperfections in phantom structure (BSD-DTI). Several cases of varying degrees of phantom uniformity were analyzed and the distributions of the B-matrix obtained were used for the calculation of the diffusion tensor of a model isotropic phantom. The results were compared with standard diffusion tensor calculation. The simulations confirmed the improvement of accuracy in the determination of the diffusion tensor after the calibration. BSD-DTI improves accuracy independent of both the degree of uniformity of the phantom and the inhomogeneity of the B-matrix. In cases of a relatively good uniformity of the phantom and minor distortions in the spatial distribution of the B-matrix, the uBSD-DTI approach is sufficient.

  9. Pedagogical quality in e-learning - Designing e-learning from a learning theoretical approach

    Directory of Open Access Journals (Sweden)

    Christian Dalsgaard

    2005-02-01

    Full Text Available The article is concerned with design and use of e-learning technology to develop education qualitatively. The purpose is to develop a framework for a pedagogical evaluation of e-learning technology. The approach is that evaluation and design must be grounded in a learning theoretical approach, and it is argued that it is necessary to make a reflection of technology in relation to activities, learning principles, and a learning theory in order to qualitatively develop education. The article presents three frameworks developed on the basis of cognitivism, radical constructivism and activity theory. Finally, on the basis of the frameworks, the article discusses e-learning technology and, more specifically, design of virtual learning environments and learning objects. It is argued that e-learning technology is not pedagogically neutral, and that it is therefore necessary to focus on design of technology that explicitly supports a certain pedagogical approach. Further, it is argued that design should direct its focus away from organisation of content and towards design of activities.

  10. Current theoretical models fail to predict the topological complexity of the human genome.

    Science.gov (United States)

    Arsuaga, Javier; Jayasinghe, Reyka G; Scharein, Robert G; Segal, Mark R; Stolz, Robert H; Vazquez, Mariel

    2015-01-01

    Understanding the folding of the human genome is a key challenge of modern structural biology. The emergence of chromatin conformation capture assays (e.g., Hi-C) has revolutionized chromosome biology and provided new insights into the three dimensional structure of the genome. The experimental data are highly complex and need to be analyzed with quantitative tools. It has been argued that the data obtained from Hi-C assays are consistent with a fractal organization of the genome. A key characteristic of the fractal globule is the lack of topological complexity (knotting or inter-linking). However, the absence of topological complexity contradicts results from polymer physics showing that the entanglement of long linear polymers in a confined volume increases rapidly with the length and with decreasing volume. In vivo and in vitro assays support this claim in some biological systems. We simulate knotted lattice polygons confined inside a sphere and demonstrate that their contact frequencies agree with the human Hi-C data. We conclude that the topological complexity of the human genome cannot be inferred from current Hi-C data.

  11. Current protocols in the generation of pluripotent stem cells: theoretical, methodological and clinical considerations

    Directory of Open Access Journals (Sweden)

    Brad B Swelstad

    2009-12-01

    Full Text Available Brad B Swelstad, Candace L KerrInstitute for Cell Engineering, Department of Obstetrics and Gynecology, Johns Hopkins University, Baltimore, MA, USAAbstract: Pluripotent stem cells have been derived from various embryonic, fetal and adult sources. Embryonic stem cells (ESCs and parthenogenic ESCs (pESCs are derived from the embryo proper while embryonic germ cells (EGCs, embryonal carcinoma cells (ECCs, and germ-line stem cells (GSC are produced from germ cells. ECCs were the first pluripotent stem cell lines established from adult testicular tumors while EGCs are generated in vitro from primordial germ cells (PGCs isolated in late embryonic development. More recently, studies have also demonstrated the ability to produce GSCs from adult germ cells, known as spermatogonial stem cells. Unlike ECCs, the source of GSCs are normal, non-cancerous adult tissue. The study of these unique cell lines has provided information that has led to the ability to reprogram somatic cells into an ESC-like state. These cells, called induced pluripotent stem cells (iPSCs, have been derived from a number of human fetal and adult origins. With the promises pluripotent stem cells bring to cell-based therapies there remain several considerations that need to be carefully studied prior to their clinical use. Many of these issues involve understanding key factors regulating their generation, including those which define pluripotency. In this regard, the following article discusses critical aspects of pluripotent stem cell derivation and current issues about their therapeutic potential.Keywords: pluripotency, stem cells, derivation, human

  12. Current protocols in the generation of pluripotent stem cells: theoretical, methodological and clinical considerations.

    Science.gov (United States)

    Swelstad, Brad B; Kerr, Candace L

    2009-12-22

    Pluripotent stem cells have been derived from various embryonic, fetal and adult sources. Embryonic stem cells (ESCs) and parthenogenic ESCs (pESCs) are derived from the embryo proper while embryonic germ cells (EGCs), embryonal carcinoma cells (ECCs), and germ-line stem cells (GSC) are produced from germ cells. ECCs were the first pluripotent stem cell lines established from adult testicular tumors while EGCs are generated in vitro from primordial germ cells (PGCs) isolated in late embryonic development. More recently, studies have also demonstrated the ability to produce GSCs from adult germ cells, known as spermatogonial stem cells. Unlike ECCs, the source of GSCs are normal, non-cancerous adult tissue. The study of these unique cell lines has provided information that has led to the ability to reprogram somatic cells into an ESC-like state. These cells, called induced pluripotent stem cells (iPSCs), have been derived from a number of human fetal and adult origins. With the promises pluripotent stem cells bring to cell-based therapies there remain several considerations that need to be carefully studied prior to their clinical use. Many of these issues involve understanding key factors regulating their generation, including those which define pluripotency. In this regard, the following article discusses critical aspects of pluripotent stem cell derivation and current issues about their therapeutic potential.

  13. A THEORETICAL APPROACH ON THE STRATEGIC PARTNERSHIP BETWEEN THE EUROPEAN UNION AND THE RUSSIAN FEDERATION

    Directory of Open Access Journals (Sweden)

    Razvan-Alexandru GENTIMIR

    2015-08-01

    Full Text Available The purpose of this paper is to explore the theoretical approaches of the „strategic partnership” concept, and then applying them to the relationship and cooperation between the European Union and the Russian Federation, thus emphasizing its evolution. The base of this article lays on a literature review that gathers recent articles and several studies of some researchers in the field, providing some professional information on the subject. Findings reveal that there has not yet got to a general definition of the concepts, researchers and not only would agree upon, and, when applying it to the EU-Russia relation, that there are some mutual benefits as a result of the cooperation. This article shows that, despite of the fact that the startup of the cooperation between the two major global powers was a good one, it now has reached some kind of dead moment, when policy contradictions block the evolution of the partnership.

  14. A Game-Theoretic Approach to Branching Time Abstract-Check-Refine Process

    Science.gov (United States)

    Wang, Yi; Tamai, Tetsuo

    2009-01-01

    Since the complexity of software systems continues to grow, most engineers face two serious problems: the state space explosion problem and the problem of how to debug systems. In this paper, we propose a game-theoretic approach to full branching time model checking on three-valued semantics. The three-valued models and logics provide successful abstraction that overcomes the state space explosion problem. The game style model checking that generates counter-examples can guide refinement or identify validated formulas, which solves the system debugging problem. Furthermore, output of our game style method will give significant information to engineers in detecting where errors have occurred and what the causes of the errors are.

  15. A Narrative Approach to Both Teaching and Learning About Democracy with Young Children: A Theoretical Exploration

    Directory of Open Access Journals (Sweden)

    maila dinia husni rahim

    2016-03-01

    Full Text Available As adults, we often believe that children are only interested with games and children’s ‘stuff’. However research has shown that children do indeed show a greater interest in the world around them, including about politics, elections, and democracy. If we need to teach children about democracy, what are the best methods of teaching democracy to young children? Narrative is considered as an effective medium to convey messages to children and discuss hard subjects. This paper is a theoretical exploration that looks at the narrative approach to teaching and learning about democracy with young children. The researchers has used a literature review to look at why narratives should be used, what narratives should be used and how to use narratives.

  16. Information propagation and collective consensus in blogosphere: a game-theoretical approach

    CERN Document Server

    Liu, L; Wang, L; Fu, Feng; Liu, Lianghuan; Wang, Long

    2007-01-01

    In this paper, we study the information propagation in an empirical blogging network by game-theoretical approach. The blogging network has small-world property and is scale-free. Individuals in the blogosphere coordinate their decisions according to their idiosyncratic preferences and the choices of their neighbors. We find that corresponding to different initial conditions and weights, the equilibrium frequency of discussions has a transition from high to low as a result of the common interest in the topics specified by payoff matrices. Furthermore, under recommendation, namely, individuals in blogging networks refer to additional bloggers' resources besides their nearest neighbors preferentially according to the popularity of the blogs, the whole blogging network ultrafastly evolves into consensus state (absorbing state). Our results reflect the dynamic pattern of information propagation in blogging networks.

  17. Dynamic Load on a Pipe Caused by Acetylene Detonations – Experiments and Theoretical Approaches

    Directory of Open Access Journals (Sweden)

    Axel Sperber

    1999-01-01

    Full Text Available The load acting on the wall of a pipe by a detonation, which is travelling through, is not yet well characterized. The main reasons are the limited amount of sufficiently accurate pressure time history data and the requirement of considering the dynamics of the system. Laser vibrometry measurements were performed to determine the dynamic response of the pipe wall on a detonation. Different modelling approaches were used to quantify, theoretically, the radial displacements of the pipe wall. There is good agreement between measured and predicted values of vibration frequencies and the propagation velocities of transverse waves. Discrepancies mainly due to wave propagation effects were found in the amplitudes of the radial velocities. They might be overcome by the use of a dynamic load factor or improved modelling methods.

  18. Theoretical approaches to control spin dynamics in solid-state nuclear magnetic resonance

    Indian Academy of Sciences (India)

    Eugene Stephane Mananga

    2015-12-01

    This article reviews theoretical approaches for controlling spin dynamics in solid-state nuclear magnetic resonance. We present fundamental theories in the history of NMR, namely, the average Hamiltonian and Floquet theories. We also discuss emerging theories such as the Fer and Floquet-Magnus expansions. These theories allow one to solve the time-dependent Schrodinger equation, which is still the central problem in spin dynamics of solid-state NMR. Examples from the literature that highlight several applications of these theories are presented, and particular attention is paid to numerical integrators and propagator operators. The problem of time propagation calculated with Chebychev expansion and the future development of numerical directions with the Cayley transformation are considered. The bibliography includes 190 references.

  19. The game as strategy for approach to sexuality with adolescents: theoretical-methodological reflections.

    Science.gov (United States)

    Souza, Vânia de; Gazzinelli, Maria Flávia; Soares, Amanda Nathale; Fernandes, Marconi Moura; Oliveira, Rebeca Nunes Guedes de; Fonseca, Rosa Maria Godoy Serpa da

    2017-04-01

    To describe the Papo Reto [Straight Talk] game and reflect on its theoretical-methodological basis. Analytical study on the process of elaboration of the Papo Reto online game, destined to adolescents aged 15-18 years, with access to the Game between 2014 and 2015. the interactions of 60 adolescents from Belo Horizonte and São Paulo constituted examples of the potentialities of the Game to favor the approach to sexuality with adolescents through simulation of reality, invention and interaction. Based on those potentialities, four thinking categories were discussed: the game as pedagogic device; the game as simulation of realities; the game as device for inventive learning; and the game empowering the interaction. By permitting that the adolescents take risks on new ways, the Game allows them to become creative and active in the production of senses, in the creation of their discourses and in the ways of thinking, feeling and acting in the sexuality field.

  20. Understanding confounding effects in linguistic coordination: an information-theoretic approach

    CERN Document Server

    Gao, Shuyang; Galstyan, Aram

    2014-01-01

    We suggest an information-theoretic approach for measuring linguistic style coordination in dialogues. The proposed measure has a simple predictive interpretation and can account for various confounding factors through proper conditioning. We revisit some of the previous studies that reported strong sig- natures of stylistic accommodation, and find that a significant part of the observed coordination can be attributed to a simple confounding effect - length coordination. Specifically, longer utterances tend to be followed by longer responses, which gives rise to spurious correlations in the other stylistic features. We propose a test to distinguish correlations in length due to contextual factors (topic of conversation, user verbosity, etc.) and turn-by-turn coordination. We also suggest a test to identify whether stylistic coordination persists even after accounting for length coordination and contextual factors.

  1. A field-theoretic approach to linear scaling \\textit{ab-initio} molecular dynamics

    CERN Document Server

    Richters, Dorothee; Kühne, Thomas D

    2012-01-01

    We present a field-theoretic method suitable for linear scaling molecular dynamics simulations using forces from self-consistent electronic structure calculations. It is based on an exact decomposition of the grand canonical potential for independent fermions and does neither rely on the ability to localize the orbitals nor that the Hamilton operator is well-conditioned. Hence, this scheme enables highly accurate all-electron linear scaling calculations even for metallic systems. The inherent energy drift of Born-Oppenheimer molecular dynamics simulations, arising from an incomplete convergence of the self-consistent field cycle, is solved by means of a properly modified Langevin equation. The predictive power of this approach is illustrated using the example of liquid methane under extreme conditions.

  2. Theoretical investigation of antiferroelectric (SmCA*) subphases by hydrodynamical approach

    Science.gov (United States)

    Lahiri, T.; Pal Majumder, T.

    2011-12-01

    We provide a hydrodynamical approach utilizing time dependent Landau-Ginzburg model (L-G) and the Cahn-Hilliard model (C-H) to investigate antiferroelectric liquid crystals (AFLCs) exhibiting different chiral phases between paraelectric smectic A (SmA*) phase and antiferroelectric smectic CA* phase (SmCA*). Introducing conserved and non-conserved order parameters in C-H and L-G models, we have predicted the appearance of a chiral smectic C (SmC*) phase and a ferrielectric SmCFI1* phase (three layers SmCA*) in an antiferroelectric phase sequence. The three layers periodicity for SmCFI1* phase is studied in detail with a non-uniform layer interactions among smectic layers with strong experimental support. Finally, we provide some theoretical basis for the non-uniformity of our proposed layer interactions.

  3. A Theoretical Analysis of the Mission Statement Based on the Axiological Approach

    Directory of Open Access Journals (Sweden)

    Marius-Costel EŞI

    2016-12-01

    Full Text Available The aim of this work is focused on a theoretical analysis of formulating the mission statement of business organizations in relation to the idea of the organizational axiological core. On one hand, we consider the CSR-Corporate Social Responsibility which, in our view, must be brought into direct connection both with the moral entrepreneurship (which should support the philosophical perspective of the statement of business organizations mission and the purely economic entrepreneurship based on profit maximization (which should support the pragmatic perspective. On the other hand, an analysis of the moral concepts which should underpin business is becoming fundamental, in our view, as far as the idea of the social specific value of the social entrepreneurship is evidenced. Therefore, our approach highlights a number of epistemic explanations in relation to the actual practice dimension.

  4. Analysing Buyers' and Sellers' Strategic Interactions in Marketplaces: An Evolutionary Game Theoretic Approach

    Science.gov (United States)

    Vytelingum, Perukrishnen; Cliff, Dave; Jennings, Nicholas R.

    We develop a new model to analyse the strategic behaviour of buyers and sellers in market mechanisms. In particular, we wish to understand how the different strategies they adopt affect their economic efficiency in the market and to understand the impact of these choices on the overall efficiency of the marketplace. To this end, we adopt a two-population evolutionary game theoretic approach, where we consider how the behaviours of both buyers and sellers evolve in marketplaces. In so doing, we address the shortcomings of the previous state-of-the-art analytical model that assumes that buyers and sellers have to adopt the same mixed strategy in the market. Finally, we apply our model in one of the most common market mechanisms, the Continuous Double Auction, and demonstrate how it allows us to provide new insights into the strategic interactions of such trading agents.

  5. A theoretical approach to room acoustic simulations based on a radiative transfer model

    DEFF Research Database (Denmark)

    Ruiz-Navarro, Juan-Miguel; Jacobsen, Finn; Escolano, José

    2010-01-01

    A theoretical approach to room acoustic simulations based on a radiative transfer model is developed by adapting the classical radiative transfer theory from optics to acoustics. The proposed acoustic radiative transfer model expands classical geometrical room acoustic modeling algorithms...... by incorporating a propagation medium that absorbs and scatters radiation, handling both diffuse and non-diffuse reflections on boundaries and objects in the room. The main scope of this model is to provide a proper foundation for a wide number of room acoustic simulation models, in order to establish and unify...... their principles. It is shown that this room acoustic modeling technique establishes the basis of two recently proposed algorithms, the acoustic diffusion equation and the room acoustic rendering equation. Both methods are derived in detail using an analytical approximation and a simplified integral equation...

  6. Combined action of ionizing radiation with another factor: common rules and theoretical approach

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Kyu; Roh, Changhyun, E-mail: jkkim@kaeri.re.kr [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Komarova, Ludmila N.; Petin, Vladislav G., E-mail: vgpetin@yahoo.com [Medical Radiological Research Center, Obninsk (Russian Federation)

    2013-07-01

    Two or more factors can simultaneously make their combined effects on the biological objects. This study has focused on theoretical approach to synergistic interaction due to the combined action of radiation and another factor on cell inactivation. A mathematical model for the synergistic interaction of different environmental agents was suggested for quantitative prediction of irreversibly damaged cells after combined exposures. The model takes into account the synergistic interaction of agents and based on the supposition that additional effective damages responsible for the synergy are irreversible and originated from an interaction of ineffective sub lesions. The experimental results regarding the irreversible component of radiation damage of diploid yeast cells simultaneous exposed to heat with ionizing radiation or UV light are presented. A good agreement of experimental results with model predictions was demonstrated. The importance of the results obtained for the interpretation of the mechanism of synergistic interaction of various environmental factors is discussed. (author)

  7. Predictive coding and the slowness principle: an information-theoretic approach.

    Science.gov (United States)

    Creutzig, Felix; Sprekeler, Henning

    2008-04-01

    Understanding the guiding principles of sensory coding strategies is a main goal in computational neuroscience. Among others, the principles of predictive coding and slowness appear to capture aspects of sensory processing. Predictive coding postulates that sensory systems are adapted to the structure of their input signals such that information about future inputs is encoded. Slow feature analysis (SFA) is a method for extracting slowly varying components from quickly varying input signals, thereby learning temporally invariant features. Here, we use the information bottleneck method to state an information-theoretic objective function for temporally local predictive coding. We then show that the linear case of SFA can be interpreted as a variant of predictive coding that maximizes the mutual information between the current output of the system and the input signal in the next time step. This demonstrates that the slowness principle and predictive coding are intimately related.

  8. Neuropsychiatric involvement in systemic lupus erythematosus: current therapeutic approach.

    Science.gov (United States)

    Sanna, Giovanni; Bertolaccini, Maria Laura; Khamashta, Munther A

    2008-01-01

    The involvement of the central nervous system (CNS) is one of the major causes of morbidity and mortality in systemic lupus erythematosus (SLE) patients and the less understood aspect of the disease. Its recognition and treatment continue to represent a major diagnostic and therapeutic challenge. Due to the lack of controlled randomized trials, current therapeutic approach is still empirical and based on clinical experience. The therapeutic choice depends on accurate diagnosis, identification of underlying pathogenic mechanism, severity of the presenting neuropsychiatric symptoms, and on prompt identification and management of contributing causes of CNS disease. Mild neuropsychiatric manifestations may need symptomatic treatment only. In more severe CNS disease it is important to distinguish between thrombotic and non-thrombotic mechanisms. Focal CNS manifestations, particularly TIA and stroke, are associated with the presence of antiphospholipid antibodies (aPL). Anticoagulation is warranted in patients with thrombotic disease, particularly in those with the antiphospholipid (Hughes) syndrome (APS). Other CNS manifestations, such as demyelinating syndrome, transverse myelitis, chorea, seizures, migraine and/or cognitive dysfunction, when associated with persistent positivity for aPL, may also benefit from anticoagulation in selected patients. Severe diffuse CNS manifestations, such as acute confusional state, generalised seizures, mood disorders and psychosis, generally require corticosteroids in the first instance. Pulse intravenous cyclophosphamide therapy may help when more severe manifestations are refractory to corticosteroids and other immunosuppressive agents, generally when response is not seen in 3-5 days. Plasmapheresis may also be added in severe cases of symptoms refractory to conventional treatment. Intravenous immunoglobulins, mycophenolate mofetil, rituximab, intratecal methotrexate and dexametasone deserve further studies to confirm their

  9. CURRENT APPROACHES TO UNIVERSAL VACCINE AGAINST INFLUENZA VIRUS

    Directory of Open Access Journals (Sweden)

    I. B. Esmagambetov

    2016-01-01

    Full Text Available Influenza is a seasonal infectious disease widespread across the globe. In Russia the share of influenza and other acute respiratory viral infections account for up to 90% of all infectious diseases. Scientific and reasonable method of influenza prevention is vaccination. However, traditional current influenza vaccines can’t induce protection against various virus strains that differ substantially in terms of their antigenic structure, and thus require periodic updates to its immunogenic components. In addition, there is the risk of a pandemic caused by an entirely new antigen in relation to variants of influenza virus A. Attempts to improve on traditional approaches to vaccination have focused primarily on improving production technologies and to increase immunogenicity of vaccines. Therefore, the urgent task is the creation of vaccines able to induce immune response a broad spectrum against different influenza virus strains and human strains of avian influenza, also can cause disease in humans. Protective effect of universal vaccine should be the induction of integrated immune response, based on the formulation of cross-reactive antibodies and T cells. The development of such universal vaccine could remove the need for periodical strain composition update of existing vaccines and, accor dingly, will be able to give the vaccine manufacturer itself, production planning regardless of epidemic seasons. Currently, the most widely studied antigens as key components of flu vaccines are proteins M2 and NP as well as the hemagglutinin of influenza virus. This review summarizes and lists some data of domestic and foreign research on a universal influenza virus vaccine.

  10. Current Perspectives on Desmoid Tumors: The Mayo Clinic Approach

    Directory of Open Access Journals (Sweden)

    Scott Okuno

    2011-08-01

    Full Text Available Desmoid tumors are a rare group of locally aggressive, non malignant tumors of fibroblastic origin that can lead to significant morbidity due to local invasion. Despite advances in the understanding of these tumors, their natural history is incompletely understood and the optimal treatment is still a matter of debate. Local control is the main goal of treatment and there has been a change in philosophy regarding the management of these tumors from aggressive surgical resection to function preservation. A multidisciplinary approach is essential to plan local control with acceptable morbidity. The current Mayo Clinic algorithm for the treatment of these tumors is based on institutional experience and the available evidence in the literature: asymptomatic/non progressive lesions away from vital structures are managed with observation and regular imaging; primary or recurrent desmoid tumors which are symptomatic or progressive or near vital structures are managed with wide surgical resection when wide surgical margins are possible with minimal functional and cosmetic loss. When positive or close surgical margins are likely, surgical resection with adjuvant radiotherapy or definitive radiotherapy is preferred. If likely functional or cosmetic deficit is unacceptable, radiotherapy is the treatment of choice. Unresectable lesions are considered for radiotherapy, chemotherapy or newer modalities however an unresectable lesion associated with a painful, functionless, infected extremity is managed with an amputation.

  11. Current Approach to the Evaluation and Management of Microscopic Colitis.

    Science.gov (United States)

    Cotter, Thomas G; Pardi, Darrell S

    2017-02-01

    Microscopic colitis is a common cause of chronic watery diarrhea, particularly in the elderly. The accompanying symptoms, which include abdominal pain and fatigue, can markedly impair patients' quality of life. Diagnosis is based upon characteristic histologic findings of the colonic mucosa. This review focuses on the current approach to evaluation and management of patients with microscopic colitis. Although the incidence of microscopic colitis has been increasing over time, recent epidemiological studies show stabilization at 21.0-24.7 cases per 100,000 person-years. Recent research has further expanded our knowledge of the underlying pathophysiology and emphasized the entity of drug-induced microscopic colitis and the association with celiac disease. Two recent randomized studies have confirmed the effectiveness of oral budesonide for both induction and maintenance treatment of microscopic colitis and is now endorsed by the American Gastroenterological Association as first-line treatment. The incidence of microscopic colitis has stabilized at just over 20 cases per 100,000 person-years. Celiac disease and drug-induced microscopic colitis should be considered in all patients diagnosed with microscopic colitis. There are a number of treatments available for patients with microscopic colitis; however, budesonide is the only option well studied in controlled trials and is effective for both induction and maintenance treatment.

  12. Current Approaches and Future Trends to Promote Tendon Repair.

    Science.gov (United States)

    Morais, D S; Torres, J; Guedes, R M; Lopes, M A

    2015-09-01

    Tendons are composed by extracellular collagen fibres arranged in regular arrays and are responsible to transmit tensile forces from a muscle to a bone. Due to their poor healing ability, in some cases tendons injuries are debilitating impairments that affect life quality among adult population worldwide. In the last years, attending to the social and economic concern associated to the high prevalence of tendons injuries and the limited success of the available current treatments, several scaffolds have been developed. Some of these scaffolds are intended to be used as graft-augmentation devices and others to fully replace a damaged tendon. The synthetic ones present superior mechanical characteristics compared to biological scaffolds. However, attending to the specific tendons physiology, even the synthetic scaffolds still don´t present the ideal mechanical properties to accomplish a complete and long-term functional tissue repair. Therefore, to enhance tendogenesis when using a tendon engineering approach, several methodologies have been developed to associate with scaffolds, including surface modification and cell seeding.

  13. Current approaches for the treatment of autoimmune hemolytic anemia.

    Science.gov (United States)

    Jaime-Pérez, José Carlos; Rodríguez-Martínez, Marisol; Gómez-de-León, Andrés; Tarín-Arzaga, Luz; Gómez-Almaguer, David

    2013-10-01

    Autoimmune hemolytic anemia (AIHA) is an infrequent group of diseases defined by autoantibody mediated red blood cell destruction. Correct diagnosis and classification of this condition are essential to provide appropriate treatment. AIHA is divided into warm and cold types according to the characteristics of the autoantibody involved and by the presence of an underlying or associated disorder into primary and secondary AIHA. Due to its low frequency, treatment for AIHA is largely based on small prospective trials, case series, and empirical observations. This review describes in detail the different treatment approaches for autoimmune hemolytic anemia. Warm antibody type AIHA should be treated with steroids, to which most patients respond, although relapse can occur and maintenance doses are frequently required. Splenectomy is an effective second line treatment and can provide long-term remission without medication. Rituximab is a useful alternative for steroid refractory patients, those requiring high maintenance doses and unfavorable candidates for surgery. Promising therapeutic modifications with this monoclonal antibody are emerging including drug combinations, lower doses, and long-term use. Primary cold agglutinin disease has been recognized as having a lymphoproliferative monoclonal origin. It is unresponsive to both steroids and splenectomy. Rituximab is currently the best therapeutic alternative for this condition, and several treatment regimens are available with variable responses.

  14. Current Perspectives on Desmoid Tumors: The Mayo Clinic Approach

    Energy Technology Data Exchange (ETDEWEB)

    Joglekar, Siddharth B. [Musculoskeletal Oncology, Mayo Clinic, Rochester, MN55905 (United States); Rose, Peter S.; Sim, Franklin, E-mail: sim.franklin@mayo.edu [Department of Orthopedics, Mayo Clinic, 200 1st ST SW, Rochester, MN 55905 (United States); Okuno, Scott [Department of Oncology, Mayo Clinic, Rochester, MN55905 (United States); Petersen, Ivy [Department of Radiation Oncology, Mayo Clinic, Rochester, MN55905 (United States)

    2011-08-08

    Desmoid tumors are a rare group of locally aggressive, non malignant tumors of fibroblastic origin that can lead to significant morbidity due to local invasion. Despite advances in the understanding of these tumors, their natural history is incompletely understood and the optimal treatment is still a matter of debate. Local control is the main goal of treatment and there has been a change in philosophy regarding the management of these tumors from aggressive surgical resection to function preservation. A multidisciplinary approach is essential to plan local control with acceptable morbidity. The current Mayo Clinic algorithm for the treatment of these tumors is based on institutional experience and the available evidence in the literature: asymptomatic/non progressive lesions away from vital structures are managed with observation and regular imaging; primary or recurrent desmoid tumors which are symptomatic or progressive or near vital structures are managed with wide surgical resection when wide surgical margins are possible with minimal functional and cosmetic loss. When positive or close surgical margins are likely, surgical resection with adjuvant radiotherapy or definitive radiotherapy is preferred. If likely functional or cosmetic deficit is unacceptable, radiotherapy is the treatment of choice. Unresectable lesions are considered for radiotherapy, chemotherapy or newer modalities however an unresectable lesion associated with a painful, functionless, infected extremity is managed with an amputation.

  15. A Non-Cooperative Game Theoretical Approach For Power Control In Virtual MIMO Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    R.Valli

    2010-07-01

    Full Text Available Power management is one of the vital issue in wireless sensor networks, where the lifetime of the networkrelies on battery powered nodes. Transmitting at high power reduces the lifetime of both the nodes andthe network. One efficient way of power management is to control the power at which the nodes transmit.In this paper, a virtual multiple input multiple output wireless sensor network (VMIMO-WSNcommunication architecture is considered and the power control of sensor nodes based on the approachof game theory is formulated. The use of game theory has proliferated, with a broad range of applicationsin wireless sensor networking. Approaches from game theory can be used to optimize node level as wellas network wide performance. The game here is categorized as an incomplete information game, in whichthe nodes do not have complete information about the strategies taken by other nodes. For virtualmultiple input multiple output wireless sensor network architecture considered, the Nash equilibrium isused to decide the optimal power level at which a node needs to transmit, to maximize its utility. Outcomeshows that the game theoretic approach considered for VMIMO-WSN architecture achieves the bestutility, by consuming less power.

  16. The prediction of candidate genes for cervix related cancer through gene ontology and graph theoretical approach.

    Science.gov (United States)

    Hindumathi, V; Kranthi, T; Rao, S B; Manimaran, P

    2014-06-01

    With rapidly changing technology, prediction of candidate genes has become an indispensable task in recent years mainly in the field of biological research. The empirical methods for candidate gene prioritization that succors to explore the potential pathway between genetic determinants and complex diseases are highly cumbersome and labor intensive. In such a scenario predicting potential targets for a disease state through in silico approaches are of researcher's interest. The prodigious availability of protein interaction data coupled with gene annotation renders an ease in the accurate determination of disease specific candidate genes. In our work we have prioritized the cervix related cancer candidate genes by employing Csaba Ortutay and his co-workers approach of identifying the candidate genes through graph theoretical centrality measures and gene ontology. With the advantage of the human protein interaction data, cervical cancer gene sets and the ontological terms, we were able to predict 15 novel candidates for cervical carcinogenesis. The disease relevance of the anticipated candidate genes was corroborated through a literature survey. Also the presence of the drugs for these candidates was detected through Therapeutic Target Database (TTD) and DrugMap Central (DMC) which affirms that they may be endowed as potential drug targets for cervical cancer.

  17. A theoretical approach for the assessment of intralaminar fracture mode and toughness of multilayered composites

    Indian Academy of Sciences (India)

    P N Dileep; R Ramesh Kumar

    2011-02-01

    Analytical evaluation of fracture toughness of a multilayered composite laminate was well-established using modified crack closure integral (MCCI) approach based on test data on the failure load. For this purpose the crack initiation direction, which is treated as a branch crack direction for the theoretical prediction, is required. The crack initiation direction in a multilayered composite laminate depends on mode of failure. In the present work, a fracture parameter $n^∗$ is introduced to predict the mode of failure in multilayered composite having a crack and is validated. Analytical relationship for the prediction of fracture toughness of multilayered composite between a base laminate and its constituent sublaminates is also arrived at. With available test data on the toughness of a set of sub-laminates, toughness of base laminate is determined and validated. The present approach is useful in evaluating the load carrying capability of composite structures with defects in the form of cracks and this information is valuable for design.

  18. A Theoretical Approach to Understanding Population Dynamics with Seasonal Developmental Durations

    Science.gov (United States)

    Lou, Yijun; Zhao, Xiao-Qiang

    2017-04-01

    There is a growing body of biological investigations to understand impacts of seasonally changing environmental conditions on population dynamics in various research fields such as single population growth and disease transmission. On the other side, understanding the population dynamics subject to seasonally changing weather conditions plays a fundamental role in predicting the trends of population patterns and disease transmission risks under the scenarios of climate change. With the host-macroparasite interaction as a motivating example, we propose a synthesized approach for investigating the population dynamics subject to seasonal environmental variations from theoretical point of view, where the model development, basic reproduction ratio formulation and computation, and rigorous mathematical analysis are involved. The resultant model with periodic delay presents a novel term related to the rate of change of the developmental duration, bringing new challenges to dynamics analysis. By investigating a periodic semiflow on a suitably chosen phase space, the global dynamics of a threshold type is established: all solutions either go to zero when basic reproduction ratio is less than one, or stabilize at a positive periodic state when the reproduction ratio is greater than one. The synthesized approach developed here is applicable to broader contexts of investigating biological systems with seasonal developmental durations.

  19. Person-centred health care: a critical assessment of current and emerging research approaches.

    Science.gov (United States)

    Martin, Carmel M; Félix-Bortolotti, Margot

    2014-12-01

    Person-centred health care is prominent in international health care reforms. A shift to understanding and improving personal care at the point of delivery has generated debates about the nature of the person-centred research agenda. This paper purviews research paradigms that influence current person-centred research approaches and traditions that influence knowledge foundations in the field. It presents a synthesis of the emergent approaches and methodologies and highlights gaps between static academic research and the increasing accessibility of evaluation, informatics and big data from health information systems. Paradigms in health services research range from theoretical to atheoretical, including positivist, interpretive, postmodern and pragmatic. Interpretivist (subjective) and positivist (objectivist) paradigms have been historically polarized. Yet, integrative and pragmatic approaches have emerged. Nevertheless, there is a tendency to reductionism, and to reduce personal experiences to metrics in the positivist paradigm. Integrating personalized information into clinical systems is increasingly driven by the pervasive health information technology, which raises many issues about the asymmetry and uncertainty in the flow of information to support personal health journeys. The flux and uncertainty of knowledge between and within paradigmatic or pragmatic approaches highlights the uncertainty and the 'unorder and disorder' in what is known and what it means. Transdisciplinary, complex adaptive systems theory with multi-ontology sense making provides an overarching framework for making sense of the complex dynamics in research progress. A major challenge to current research paradigms is focus on the individualizing of care and enhancing experiences of persons in health settings. There is an urgent need for person-centred research to address this complex process. A transdisciplinary and complex systems approach provides a sense-making framework. © 2014 John

  20. An information theoretic approach for generating an aircraft avoidance Markov Decision Process

    Science.gov (United States)

    Weinert, Andrew J.

    Developing a collision avoidance system that can meet safety standards required of commercial aviation is challenging. A dynamic programming approach to collision avoidance has been developed to optimize and generate logics that are robust to the complex dynamics of the national airspace. The current approach represents the aircraft avoidance problem as Markov Decision Processes and independently optimizes a horizontal and vertical maneuver avoidance logics. This is a result of the current memory requirements for each logic, simply combining the logics will result in a significantly larger representation. The "curse of dimensionality" makes it computationally inefficient and unfeasible to optimize this larger representation. However, existing and future collision avoidance systems have mostly defined the decision process by hand. In response, a simulation-based framework was built to better understand how each potential state quantifies the aircraft avoidance problem with regards to safety and operational components. The framework leverages recent advances in signals processing and database, while enabling the highest fidelity analysis of Monte Carlo aircraft encounter simulations to date. This framework enabled the calculation of how well each state of the decision process quantifies the collision risk and the associated memory requirements. Using this analysis, a collision avoidance logic that leverages both horizontal and vertical actions was built and optimized using this simulation based approach.

  1. Robotic surgery for gastric tumor: current status and new approaches.

    Science.gov (United States)

    Lim, Seung Hyun; Lee, Hae Min; Son, Taeil; Hyung, Woo Jin; Kim, Hyoung-Il

    2016-01-01

    Surgical techniques have evolved tremendously over this past century. To maximize the efficacy and minimize the invasiveness of laparoscopic surgery, researchers have sought to implement wider application of robotics. Nevertheless, both optimism without sound evidence and fear of new technology obscure the appropriate uses of robotic surgery. In the present review, we attempted to provide a balanced perspective on the current state of robotic gastrectomy, outlining evidence and opportunities for the use thereof. Although evidence is limited, the use of robotics is feasible for gastric cancer surgery, and less than 10 cases of robotic surgery are needed to become proficient therein. Compared to the clinical impact of laparoscopy on gastric cancer surgery, the additional benefits of robotic surgery to patients seem to be limited. Despite additional costs and longer surgeries, robotic surgery reportedly does not offer surgical outcomes superior to those for laparoscopic surgery, according to a recent multicenter study. Meanwhile, however, our in-depth review of retrospective and prospective reports revealed that robots could expand the indications of minimally invasive gastrectomy for patients requiring total gastrectomy and D2 lymph node dissection. Moreover, we found that robotic gastrectomy is associated with a higher number of retrieved lymph nodes, less bleeding, fewer complications, and shorter hospital stay, compared to laparoscopic gastrectomy. Accordingly, new surgical approaches using advanced technologies, such as near infrared detectors, the Tilepro(®) multi-input display, dual consoles, and the Single-Site(®) system, are under investigation. In conclusion, measuring the additional benefits of robotic over laparoscopic surgery would be difficult and clinically insignificant. Thus, developing new surgical procedures that extend the benefits of conventional laparoscopic surgery to patients in whom minimally invasive surgery would not be possible is

  2. Diagnostic approach and current treatment options in childhood vasculitis.

    Science.gov (United States)

    Barut, Kenan; Şahin, Sezgin; Adroviç, Amra; Kasapçopur, Özgür

    2015-12-01

    All inflammatory changes in the vessel wall are defined as vasculitis. Pediatric vasculitis may present with different clinical findings. Although Henoch-Schönlein purpura which is the most common pediatric vasculitis generally recovers spontaneously, it should be monitorized closely because of the risk of renal failure. Although Kawasaki disease is easy to diagnose with its classical findings, the diagnosis may be delayed in case of incomplete Kawasaki disease. Kawasaki disease should be considered especially in infants in case of prolonged fever even if the criteria are not fully met and intravenous immunoglobulin treatment should be administered without delay in order to prevent development of coronary artery aneurism. Reaction at the site of administration of Bacillus Calmette-Guerin (BCG) vaccine may be observed as commonly as cervical lymphadenopathy in Kawasaki disease and may be used as a valuable finding in suspicious cases. Although anti-neutrophil cytoplasmic antibody-associated vasculitides are rare in children, renal involvement is more common and progression is more severe compared to adults. Hence, efficient and aggressive treatment is required. Takayasu's arteritis is observed commonly in young adult women and rarely in adolescent girls. Therefore, a careful physical examination and blood pressure measurement should be performed in addition to a detailed history in daily practice. In children with unexplained neurological findings, cerebral vasculitis should be considered in the absence of other systemic vasculitides and necessary radiological investigations should be performed in this regard. This review will provide an insight into the understanding of pediatric vasculitis, current diagnostic approaches and prognosis by the aid of new studies.

  3. Robotic surgery for gastric tumor: current status and new approaches

    Science.gov (United States)

    Lim, Seung Hyun; Lee, Hae Min; Son, Taeil; Hyung, Woo Jin

    2016-01-01

    Surgical techniques have evolved tremendously over this past century. To maximize the efficacy and minimize the invasiveness of laparoscopic surgery, researchers have sought to implement wider application of robotics. Nevertheless, both optimism without sound evidence and fear of new technology obscure the appropriate uses of robotic surgery. In the present review, we attempted to provide a balanced perspective on the current state of robotic gastrectomy, outlining evidence and opportunities for the use thereof. Although evidence is limited, the use of robotics is feasible for gastric cancer surgery, and less than 10 cases of robotic surgery are needed to become proficient therein. Compared to the clinical impact of laparoscopy on gastric cancer surgery, the additional benefits of robotic surgery to patients seem to be limited. Despite additional costs and longer surgeries, robotic surgery reportedly does not offer surgical outcomes superior to those for laparoscopic surgery, according to a recent multicenter study. Meanwhile, however, our in-depth review of retrospective and prospective reports revealed that robots could expand the indications of minimally invasive gastrectomy for patients requiring total gastrectomy and D2 lymph node dissection. Moreover, we found that robotic gastrectomy is associated with a higher number of retrieved lymph nodes, less bleeding, fewer complications, and shorter hospital stay, compared to laparoscopic gastrectomy. Accordingly, new surgical approaches using advanced technologies, such as near infrared detectors, the Tilepro® multi-input display, dual consoles, and the Single-Site® system, are under investigation. In conclusion, measuring the additional benefits of robotic over laparoscopic surgery would be difficult and clinically insignificant. Thus, developing new surgical procedures that extend the benefits of conventional laparoscopic surgery to patients in whom minimally invasive surgery would not be possible is necessary

  4. THEORETICAL APPROACHES TO THE DEFINITION OF MOTIVATION OF PROFESSIONAL ACTIVITY OF PUBLIC SERVANTS

    Directory of Open Access Journals (Sweden)

    E. V. Vashalomidze

    2016-01-01

    Full Text Available The relevance of the topic chosen due to the presence of performance motivation development problems of civil servants, including their motivation for continuous professional development, as one of the main directions of development of the civil service in general, approved by the relevant Presidential Decree on 2016–2018 years. In the first part of this article provides a brief analytical overview and an assessment of content and process of theoretical and methodological approaches to solving the problems of motivation of the personnel of socio-economic systems. In the second part of the article on the basis of the research proposed motivating factors in the development of the approaches set out in the first part of the article.The purpose / goal. The aim of the article is to provide methodological assistance to academic institutions involved in the solution of scientific and practical problems of motivation of civil servants to the continuous professional development in accordance with the Presidential Decree of 11 August 2016 № 408.Methodology. The methodological basis of this article are: a comprehensive analysis of normative legal provision of state of the Russian Federation; systematic approach and historical analysis of the theory and methodology of solving problems of staff motivation; method of expert evaluations; the scientific method of analogies.Conclusions / relevance. The practical significance of the article is in the operational delivery of the scientific and methodological assistance to the implementation of the Russian Federation "On the main directions of the state civil service of the Russian Federation in the years 2016–2018" Presidential Decree of 11 August number 403 regarding the establishment of mechanisms to motivate civil servants to continuous professional development.

  5. Fallacies and fantasies: the theoretical underpinnings of the Coexistence Approach for palaeoclimate reconstruction

    Science.gov (United States)

    Grimm, Guido W.; Potts, Alastair J.

    2016-03-01

    The Coexistence Approach has been used to infer palaeoclimates for many Eurasian fossil plant assemblages. However, the theory that underpins the method has never been examined in detail. Here we discuss acknowledged and implicit assumptions and assess the statistical nature and pseudo-logic of the method. We also compare the Coexistence Approach theory with the active field of species distribution modelling. We argue that the assumptions will inevitably be violated to some degree and that the method lacks any substantive means to identify or quantify these violations. The absence of a statistical framework makes the method highly vulnerable to the vagaries of statistical outliers and exotic elements. In addition, we find numerous logical inconsistencies, such as how climate shifts are quantified (the use of a "centre value" of a coexistence interval) and the ability to reconstruct "extinct" climates from modern plant distributions. Given the problems that have surfaced in species distribution modelling, accurate and precise quantitative reconstructions of palaeoclimates (or even climate shifts) using the nearest-living-relative principle and rectilinear niches (the basis of the method) will not be possible. The Coexistence Approach can be summarised as an exercise that shoehorns a plant fossil assemblage into coexistence and then assumes that this must be the climate. Given the theoretical issues and methodological issues highlighted elsewhere, we suggest that the method be discontinued and that all past reconstructions be disregarded and revisited using less fallacious methods. We outline six steps for (further) validation of available and future taxon-based methods and advocate developing (semi-quantitative) methods that prioritise robustness over precision.

  6. An information-theoretic approach to assess practical identifiability of parametric dynamical systems.

    Science.gov (United States)

    Pant, Sanjay; Lombardi, Damiano

    2015-10-01

    A new approach for assessing parameter identifiability of dynamical systems in a Bayesian setting is presented. The concept of Shannon entropy is employed to measure the inherent uncertainty in the parameters. The expected reduction in this uncertainty is seen as the amount of information one expects to gain about the parameters due to the availability of noisy measurements of the dynamical system. Such expected information gain is interpreted in terms of the variance of a hypothetical measurement device that can measure the parameters directly, and is related to practical identifiability of the parameters. If the individual parameters are unidentifiable, correlation between parameter combinations is assessed through conditional mutual information to determine which sets of parameters can be identified together. The information theoretic quantities of entropy and information are evaluated numerically through a combination of Monte Carlo and k-nearest neighbour methods in a non-parametric fashion. Unlike many methods to evaluate identifiability proposed in the literature, the proposed approach takes the measurement-noise into account and is not restricted to any particular noise-structure. Whilst computationally intensive for large dynamical systems, it is easily parallelisable and is non-intrusive as it does not necessitate re-writing of the numerical solvers of the dynamical system. The application of such an approach is presented for a variety of dynamical systems--ranging from systems governed by ordinary differential equations to partial differential equations--and, where possible, validated against results previously published in the literature. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. PREFACE: The Second International Conference on Inverse Problems: Recent Theoretical Developments and Numerical Approaches

    Science.gov (United States)

    Cheng, Jin; Hon, Yiu-Chung; Seo, Jin Keun; Yamamoto, Masahiro

    2005-01-01

    The Second International Conference on Inverse Problems: Recent Theoretical Developments and Numerical Approaches was held at Fudan University, Shanghai from 16-21 June 2004. The first conference in this series was held at the City University of Hong Kong in January 2002 and it was agreed to hold the conference once every two years in a Pan-Pacific Asian country. The next conference is scheduled to be held at Hokkaido University, Sapporo, Japan in July 2006. The purpose of this series of biennial conferences is to establish and develop constant international collaboration, especially among the Pan-Pacific Asian countries. In recent decades, interest in inverse problems has been flourishing all over the globe because of both the theoretical interest and practical requirements. In particular, in Asian countries, one is witnessing remarkable new trends of research in inverse problems as well as the participation of many young talents. Considering these trends, the second conference was organized with the chairperson Professor Li Tat-tsien (Fudan University), in order to provide forums for developing research cooperation and to promote activities in the field of inverse problems. Because solutions to inverse problems are needed in various applied fields, we entertained a total of 92 participants at the second conference and arranged various talks which ranged from mathematical analyses to solutions of concrete inverse problems in the real world. This volume contains 18 selected papers, all of which have undergone peer review. The 18 papers are classified as follows: Surveys: four papers give reviews of specific inverse problems. Theoretical aspects: six papers investigate the uniqueness, stability, and reconstruction schemes. Numerical methods: four papers devise new numerical methods and their applications to inverse problems. Solutions to applied inverse problems: four papers discuss concrete inverse problems such as scattering problems and inverse problems in

  8. CURRENT APPROACHES FOR RESEARCH OF MULTIPLE SCLEROSIS BIOMARKERS

    Directory of Open Access Journals (Sweden)

    Kolyada T.I

    2016-12-01

    Full Text Available Current data concerning features of multiple sclerosis (MS etiology, pathogenesis, clinical course and treatment of disease indicate the necessity of personalized approach to the management of MS patients. These features are the variety of possible etiological factors and mechanisms that trigger the development of MS, different courses of disease, and significant differences in treatment efficiency. Phenotypic and pathogenetic heterogeneity of MS requires, on the one hand, the stratification of patients into groups with different treatment depending on a number of criteria including genetic characteristics, disease course, stage of the pathological process, and forms of the disease. On the other hand, it requires the use of modern methods for assessment of individual risk of developing MS, its early diagnosis, evaluation and prognosis of the disease course and the treatment efficiency. This approach is based on the identification and determination of biomarkers of MS including the use of systems biology technology platforms such as genomics, proteomics, metabolomics and bioinformatics. Research and practical use of biomarkers of MS in clinical and laboratory practice requires the use of a wide range of modern medical and biological, mathematical and physicochemical methods. The group of "classical" methods used to study MS biomarkers includes physicochemical and immunological methods aimed at the selection and identification of single molecular biomarkers, as well as methods of molecular genetic analysis. This group of methods includes ELISA, western blotting, isoelectric focusing, immunohistochemical methods, flow cytometry, spectrophotometric and nephelometric methods. These techniques make it possible to carry out both qualitative and quantitative assay of molecular biomarkers. The group of "classical methods" can also include methods based on polymerase chain reaction (including multiplex and allele-specific PCR and genome sequencing

  9. COMPARATIVE STUDY BETWEEN TRADITIONAL AND ENTERPRISE RISK MANAGEMENT -A THEORETICAL APPROACH

    Directory of Open Access Journals (Sweden)

    Cican Simona-Iulia

    2014-07-01

    Full Text Available The complexity, volatility and unpredictability of the current economic environment are a daily reminder that organizations face many risks. The traditional approach, according to which risk is a necessary evil which must be removed, is no longer sufficient and that is why companies nowadays are forced to spend significant resources to manage risks. Risk transparency is what one looks for; therefore, identification and management of risks within an organization become increasingly necessary for success and longevity. Risk approach has a major role in a company’s ability to avoid, reduce and turn risks into opportunities. Enterprise risk management is a new concept that revolutionizes the traditional approach and summarizes risk management in an integrated, comprehensive and strategic system. Studies use several synonyms for enterprise risk management such as integrated risk management, holistic risk management, global risk management and strategic risk management. Enterprise risk management implements at the end of the last century a new way to deal with risks: the holistic approach. This risks approach – i.e. interaction of several types of risks which become increasingly threatening and varied and may cause more damage than individual risk – brings forward the need of risk management and raises issues at the highest level of company management. For a proper view on company risks, each individual risk and the possibility of risk interaction must be understood. This is essential to establish a risk classification according to their impact on the company. Traditional approach on risk management, as a management function, is limited to only threats and losses, so relatively few organizations see risks as potential earning-generated opportunities. However, risk management process is not radically changed. Enterprise risk management is an improved version of the traditional risk management, created by expanding its scope. The new risk

  10. Beyond (eco)design: current approaches to sustainable packaging design

    OpenAIRE

    Wever, R.

    2014-01-01

    Packaging has always received a lot of attention within the field of design for sustainability. The classical approach has been to mainly focus on reducing the impact of the packaging. This approach stems from the ill-informed position that packaging is superfluous, or at best there only for marketing reasons. This is a rather guild-based approach that, if taken to extremes, would lead to complete elimination of packaging, or at most a quintessential brown paper bag. In industry reality thoug...

  11. MELiSSA Food Characterization general approach and current status

    Science.gov (United States)

    Weihreter, Martin; Chaerle, Laury; Secco, Benjamin; Molders, Katrien; van der Straeten, Dominique; Duliere, Eric; Pieters, Serge; Maclean, Heather; Dochain, Denis; Quinet, Muriel; Lutts, Stanley; Graham, Thomas; Stasiak, Michael; Rondeau Vuk, Theresa; Zheng, Youbin; Dixon, Mike; Laniau, Martine; Larreture, Alain; Timsit, Michel; Aronne, Giovanna; Barbieri, Giancarlo; Buonomo, Roberta; Veronica; Paradiso, Roberta; de Pascale, Stafania; Galbiati, Massimo; Troia, A. R.; Nobili, Matteo; Bucchieri, Lorenzo; Page, Valérie; Feller, Urs; Lasseur, Christophe

    . Available MELiSSA closed environment crop growth data were used to develop a first photosynthetic model representing the basic carbon fixation mechanisms. This model will be further elaborated in the course of this study to predict yield, oxygen production and transpi-ration. As an ultimate goal the model is intended to simulate the composition of the different plant organs (root, shoot, fruit/seed or tuber) for each crop under various conditions. For the validation of this model an extensive amount of data sets are needed. Current plant growth bench test setups will provide part of the required data. To gain more precise and detailed datasets, a highly closed plant growth chamber (Plant Characterization Unit, PCU) is under development. The PCU will provide accurate mass balances for carbon, water, oxygen and other elements with statistical reliability. This reliability is achieved through a high degree of closure and environment homogeneity. The PCU will also provide data for the above described plant characterization studies. The general work approach, the current status and future steps will be illustrated.

  12. A game-theoretic approach for calibration of low-cost magnetometers under noise uncertainty

    Science.gov (United States)

    Siddharth, S.; Ali, A. S.; El-Sheimy, N.; Goodall, C. L.; Syed, Z. F.

    2012-02-01

    Pedestrian heading estimation is a fundamental challenge in Global Navigation Satellite System (GNSS)-denied environments. Additionally, the heading observability considerably degrades in low-speed mode of operation (e.g. walking), making this problem even more challenging. The goal of this work is to improve the heading solution when hand-held personal/portable devices, such as cell phones, are used for positioning and to improve the heading estimation in GNSS-denied signal environments. Most smart phones are now equipped with self-contained, low cost, small size and power-efficient sensors, such as magnetometers, gyroscopes and accelerometers. A magnetometer needs calibration before it can be properly employed for navigation purposes. Magnetometers play an important role in absolute heading estimation and are embedded in many smart phones. Before the users navigate with the phone, a calibration is invoked to ensure an improved signal quality. This signal is used later in the heading estimation. In most of the magnetometer-calibration approaches, the motion modes are seldom described to achieve a robust calibration. Also, suitable calibration approaches fail to discuss the stopping criteria for calibration. In this paper, the following three topics are discussed in detail that are important to achieve proper magnetometer-calibration results and in turn the most robust heading solution for the user while taking care of the device misalignment with respect to the user: (a) game-theoretic concepts to attain better filter parameter tuning and robustness in noise uncertainty, (b) best maneuvers with focus on 3D and 2D motion modes and related challenges and (c) investigation of the calibration termination criteria leveraging the calibration robustness and efficiency.

  13. Theoretical simulations on the antioxidant mechanism of naturally occurring flavonoid: A DFT approach

    Science.gov (United States)

    Praveena, R.; Sadasivam, K.

    2016-05-01

    Synthetic antioxidants such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are found to be toxic, hence non-carcinogenic naturally occurring radical scavengers especially flavonoids have gained considerable importance in the past two decades. In the present investigation, the radical scavenging activity of C-glycosyl flavonoids is evaluated using theoretical approach which could broaden its scope in therapeutic applications. Gas and solvent phase studies of structural and molecular characteristics of C-glycosyl flavonoid, isovitexin is investigated through hydrogen atom transfer mechanism (HAT), Electron transfer-proton transfer (ET-PT) and Sequential proton loss electron transfer (SPLET) by Density functional theory (DFT) using hybrid parameters. The computed values of the adiabatic ionization potential, electron affinity, hardness, softness, electronegativity and electrophilic index indicate that isovitexin possess good radical scavenging activity. The behavior of different -OH groups in polyphenolic compounds is assessed by considering electronic effects of the neighbouring groups and the overall geometry of molecule which in turn helps in analyzing the antioxidant capacity of the polyphenolic molecule. The studies indicate that the H-atom abstraction from 4'-OH site is preferred during the radical scavenging process. From Mulliken spin density analysis and FMOs, B-ring is found to be more delocalized center and capable of electron donation. Comparison of antioxidant activity of vitexin and isovitexin leads to the conclusion that isovitexin acts as a better radical scavenger. This is an evidence for the importance of position of glucose unit in the flavonoid.

  14. Power Transmission Scheduling for Generators in a Deregulated Environment Based on a Game-Theoretic Approach

    Directory of Open Access Journals (Sweden)

    Bingtuan Gao

    2015-12-01

    Full Text Available In a deregulated environment of the power market, in order to lower their energy price and guarantee the stability of the power network, appropriate transmission lines have to be considered for electricity generators to sell their energy to the end users. This paper proposes a game-theoretic power transmission scheduling for multiple generators to lower their wheeling cost. Based on the embedded cost method, a wheeling cost model consisting of congestion cost, cost of losses and cost of transmission capacity is presented. By assuming each generator behaves in a selfish and rational way, the competition among the multiple generators is formulated as a non-cooperative game, where the players are the generators and the strategies are their daily schedules of power transmission. We will prove that there exists at least one pure-strategy Nash equilibrium of the formulated power transmission game. Moreover, a distributed algorithm will be provided to realize the optimization in terms of minimizing the wheeling cost. Finally, simulations were performed and discussed to verify the feasibility and effectiveness of the proposed non-cooperative game approach for the generators in a deregulated environment.

  15. The game as strategy for approach to sexuality with adolescents: theoretical-methodological reflections

    Directory of Open Access Journals (Sweden)

    Vânia de Souza

    Full Text Available ABSTRACT Objective: To describe the Papo Reto [Straight Talk] game and reflect on its theoretical-methodological basis. Method: Analytical study on the process of elaboration of the Papo Reto online game, destined to adolescents aged 15-18 years, with access to the Game between 2014 and 2015. Results: the interactions of 60 adolescents from Belo Horizonte and São Paulo constituted examples of the potentialities of the Game to favor the approach to sexuality with adolescents through simulation of reality, invention and interaction. Based on those potentialities, four thinking categories were discussed: the game as pedagogic device; the game as simulation of realities; the game as device for inventive learning; and the game empowering the interaction. Conclusion: By permitting that the adolescents take risks on new ways, the Game allows them to become creative and active in the production of senses, in the creation of their discourses and in the ways of thinking, feeling and acting in the sexuality field.

  16. The term of the job satisfaction: theoretical approaches and consequences in the job performance

    Directory of Open Access Journals (Sweden)

    Tsounis A.

    2016-04-01

    Full Text Available Background: Job satisfaction is one of the most widely researched subjects in Industrial/Organizational Psychology, which is being linked to many different aspects of individual and organizational function. Therefore, a variety of theories have been developed in order to explain it, while emphasis has also been given to its consequences in job performance. Objective: The aim of this study is to outline the main theories associated with explaining job satisfaction, as well as the its' consequences in job performance. Methods: The material of this review is based on the Greek and international literature. Books, articles and studies from libraries were held by hand and online databases and journals were searched with the help of keywords. Results: The most common and prominent theories in this area are separated in two main categories: the ontological approaches that are based in the content and type of human incentives and the mechanistic theories that emphasize on circumstances under which job performance and satisfaction are enhanced. Concerning job performance there is little empirical support for the straight association between job satisfaction and productivity, absence and turnover intention. Conclusions: Although none of the above theoretical frameworks can fully explain a multi-factorial phenomenon such as job satisfaction each one may contribute to its' better understanding. In addition, as far as the association between job satisfaction and different aspects of job performance the mediating role of many variables must be taken into account by the researchers

  17. Coarse-grained model of glycosaminoglycans in aqueous salt solutions. A field-theoretical approach.

    Science.gov (United States)

    Kolesnikov, Andrei L; Budkov, Yurij A; Nogovitsyn, Evgenij A

    2014-11-20

    We present results of self-consistent field calculations of thermodynamic and structural properties of glycosaminoglycans (chondroitin sulfate, hyaluronic acid, and heparin) in aqueous solutions with added monovalent and divalent salts. A semiphenomenological coarse-grained model for semiflexible polyelectrolyte chains in solution is proposed. The coarse-grained model permits one to focus on the essential features of these systems and provides significant computational advantages with respect to more detailed models. Our approach relies on the method of Gaussian equivalent representation for the calculation of the partition functions in the form of functional integrals. This method provides reliable thermodynamic information for polyelectrolyte solutions over wide ranges of monomer concentrations. In the present work, we use the comparison and fitting of the experimental osmotic pressure with a theoretical equation of state within the Gaussian equivalent representation. The degrees of ionization, radii of gyration, persistence lengths, and structure factors of chondroitin sulfate, hyaluronic acid, and heparin in aqueous solutions with added monovalent and divalent salts are calculated and discussed.

  18. Intraplate seismicity in Canada: a graph theoretic approach to data analysis and interpretation

    Directory of Open Access Journals (Sweden)

    K. Vasudevan

    2010-10-01

    Full Text Available Intraplate seismicity occurs in central and northern Canada, but the underlying origin and dynamics remain poorly understood. Here, we apply a graph theoretic approach to characterize the statistical structure of spatiotemporal clustering exhibited by intraplate seismicity, a direct consequence of the underlying nonlinear dynamics. Using a recently proposed definition of "recurrences" based on record breaking processes (Davidsen et al., 2006, 2008, we have constructed directed graphs using catalogue data for three selected regions (Region 1: 45°−48° N/74°−80° W; Region 2: 51°−55° N/77°−83° W; and Region 3: 56°−70° N/65°−95° W, with attributes drawn from the location, origin time and the magnitude of the events. Based on comparisons with a null model derived from Poisson distribution or Monte Carlo shuffling of the catalogue data, our results provide strong evidence in support of spatiotemporal correlations of seismicity in all three regions considered. Similar evidence for spatiotemporal clustering has been documented using seismicity catalogues for southern California, suggesting possible similarities in underlying earthquake dynamics of both regions despite huge differences in the variability of seismic activity.

  19. A Game Theoretic Approach to Minimize the Completion Time of Network Coded Cooperative Data Exchange

    KAUST Repository

    Douik, Ahmed S.

    2014-05-11

    In this paper, we introduce a game theoretic framework for studying the problem of minimizing the completion time of instantly decodable network coding (IDNC) for cooperative data exchange (CDE) in decentralized wireless network. In this configuration, clients cooperate with each other to recover the erased packets without a central controller. Game theory is employed herein as a tool for improving the distributed solution by overcoming the need for a central controller or additional signaling in the system. We model the session by self-interested players in a non-cooperative potential game. The utility function is designed such that increasing individual payoff results in a collective behavior achieving both a desirable system performance in a shared network environment and the Pareto optimal solution. Through extensive simulations, our approach is compared to the best performance that could be found in the conventional point-to-multipoint (PMP) recovery process. Numerical results show that our formulation largely outperforms the conventional PMP scheme in most practical situations and achieves a lower delay.

  20. Information theoretical approaches to chick-a-dee calls of Carolina chickadees (Poecile carolinensis).

    Science.gov (United States)

    Freeberg, Todd M; Lucas, Jeffrey R

    2012-02-01

    One aim of this study was to apply information theoretical analyses to understanding the structural complexity of chick-a-dee calls of Carolina chickadees, Poecile carolinensis. A second aim of this study was to compare this structural complexity to that of the calls of black-capped chickadees, P. atricapillus, described in an earlier published report (Hailman, Ficken, & Ficken, 1985). Chick-a-dee calls were recorded from Carolina chickadees in a naturalistic observation study in eastern Tennessee. Calls were analyzed using approaches from information theory, including transition probability matrices, Zipf's rules, entropies, and information coding capacities of calls and notes of calls. As described for black-capped chickadees, calls of Carolina chickadees exhibited considerable structural complexity. Most results suggested that the call of Carolina chickadees is more structurally complex than that of black-capped chickadees. These findings add support to the growing literature on the complexity of this call system in Paridae species. Furthermore, these results point to the feasibility of detailed cross-species comparative analyses that may allow strong testing of hypotheses regarding signal evolution.

  1. Mean field game theoretic approach for security in mobile ad-hoc networks

    Science.gov (United States)

    Wang, Yanwei; Tang, Helen; Yu, F. Richard; Huang, Minyi

    2013-05-01

    Game theory can provide a useful tool to study the security problem in mobile ad hoc networks (MANETs). Most existing work on applying game theories to security only considers two players in the security game model: an attacker and a defender. While this assumption is valid for a network with centralized administration, it may not be realistic in MANETs, where centralized administration is not available. Consequently, each individual node in a MANET should be treated separately in the security game model. In this paper, using recent advances in mean field game theory, we propose a novel game theoretic approach for security in MANETs. Mean field game theory provides a powerful mathematical tool for problems with a large number of players. Since security defence mechanisms consume precious system resources (e.g., energy), the proposed scheme considers not only the security requirement of MANETs but also the system resources. In addition, each node only needs to know its own state information and the aggregate effect of the other nodes in the MANET. Therefore, the proposed scheme is a fully distributed scheme. Simulation results are presented to illustrate the effectiveness of the proposed scheme.

  2. Information theoretic approach using neural network for determining radiometer observations from radar and vice versa

    Science.gov (United States)

    Kannan, Srinivasa Ramanujam; Chandrasekar, V.

    2016-05-01

    Even though both the rain measuring instruments, radar and radiometer onboard the TRMM observe the same rain scenes, they both are fundamentally different instruments. Radar is an active instrument and measures backscatter component from vertical rain structure; whereas radiometer is a passive instrument that obtains integrated observation of full depth of the cloud and rain structure. Further, their spatial resolutions on ground are different. Nevertheless, both the instruments are observing the same rain scene and retrieve three dimensional rainfall products. Hence it is only natural to seek answer to the question, what type of information about radiometric observations can be directly retrieved from radar observations. While there are several ways to answer this question, an informational theoretic approach using neural networks has been described in the present work to find if radiometer observations can be predicted from radar observations. A database of TMI brightness temperature and collocated TRMM vertical attenuation corrected reflectivity factor from the year 2012 was considered. The entire database is further classified according to surface type. Separate neural networks were trained for land and ocean and the results are presented.

  3. A graph theoretical approach for assessing bio-macromolecular complex structural stability.

    Science.gov (United States)

    Del Carpio, Carlos Adriel; Iulian Florea, Mihai; Suzuki, Ai; Tsuboi, Hideyuki; Hatakeyama, Nozomu; Endou, Akira; Takaba, Hiromitsu; Ichiishi, Eiichiro; Miyamoto, Akira

    2009-11-01

    Fast and proper assessment of bio macro-molecular complex structural rigidity as a measure of structural stability can be useful in systematic studies to predict molecular function, and can also enable the design of rapid scoring functions to rank automatically generated bio-molecular complexes. Based on the graph theoretical approach of Jacobs et al. [Jacobs DJ, Rader AJ, Kuhn LA, Thorpe MF (2001) Protein flexibility predictions using graph theory. Proteins: Struct Funct Genet 44:150-165] for expressing molecular flexibility, we propose a new scheme to analyze the structural stability of bio-molecular complexes. This analysis is performed in terms of the identification in interacting subunits of clusters of flappy amino acids (those constituting regions of potential internal motion) that undergo an increase in rigidity at complex formation. Gains in structural rigidity of the interacting subunits upon bio-molecular complex formation can be evaluated by expansion of the network of intra-molecular inter-atomic interactions to include inter-molecular inter-atomic interaction terms. We propose two indices for quantifying this change: one local, which can express localized (at the amino acid level) structural rigidity, the other global to express overall structural stability for the complex. The new system is validated with a series of protein complex structures reported in the protein data bank. Finally, the indices are used as scoring coefficients to rank automatically generated protein complex decoys.

  4. Theoretical and Experimental Approaches to the Dark Energy and the Cosmological Constant Problem

    CERN Document Server

    Borzou, Ahmad

    2016-01-01

    Theoretical and Experimental Approaches to the Dark Energy and theCosmological Constant ProblemAhmad Borzou, Ph.D.Advisor: Kenichi Hatakeyama, Ph.D.The cosmological constant problem is one of the most pressing problems ofphysics at this time. In this dissertation the problem and a set of widely-discussedtheoretical solutions to this problem are reviewed. It is shown that a recently developed Lorentz gauge theory of gravity can provide a natural solution. In this theorypresented here, the metric is not dynamical and it is shown that the Schwartzschildmetric is an exact solution. Also, it is proven that the de Sitter space is an exactvacuum solution and as a result the theory is able to explain the expansion of theuniverse with no need for dark energy. Renormalizability of the theory is studied aswell. It is also shown that, under a certain condition, the theory is power-countingrenormalizable.Supersymmetry provides an alternative solution to the cosmological problem aswell. The idea behind supersymmetry is rev...

  5. Energy-Efficient Resource Allocation in Wireless Networks: An Overview of Game-Theoretic Approaches

    CERN Document Server

    Meshkati, Farhad; Schwartz, Stuart C

    2007-01-01

    An overview of game-theoretic approaches to energy-efficient resource allocation in wireless networks is presented. Focusing on multiple-access networks, it is demonstrated that game theory can be used as an effective tool to study resource allocation in wireless networks with quality-of-service (QoS) constraints. A family of non-cooperative (distributed) games is presented in which each user seeks to choose a strategy that maximizes its own utility while satisfying its QoS requirements. The utility function considered here measures the number of reliable bits that are transmitted per joule of energy consumed and, hence, is particulary suitable for energy-constrained networks. The actions available to each user in trying to maximize its own utility are at least the choice of the transmit power and, depending on the situation, the user may also be able to choose its transmission rate, modulation, packet size, multiuser receiver, multi-antenna processing algorithm, or carrier allocation strategy. The best-respo...

  6. Theoretical Approach to the Gauge Invariant Linear Response Theories for Ultracold Fermi Gases with Pseudogap

    Directory of Open Access Journals (Sweden)

    Hao Guo

    2015-01-01

    Full Text Available Recent experimental progress allows for exploring some important physical quantities of ultracold Fermi gases, such as the compressibility, spin susceptibility, viscosity, optical conductivity, and spin diffusivity. Theoretically, these quantities can be evaluated from suitable linear response theories. For BCS superfluid, it has been found that the gauge invariant linear response theories can be fully consistent with some stringent consistency constraints. When the theory is generalized to stronger than BCS regime, one may meet serious difficulties to satisfy the gauge invariance conditions. In this paper, we try to construct density and spin linear response theories which are formally gauge invariant for a Fermi gas undergoing BCS-Bose-Einstein Condensation (BEC crossover, especially below the superfluid transition temperature Tc. We adapt a particular t-matrix approach which is close to the G0G formalism to incorporate noncondensed pairing in the normal state. We explicitly show that the fundamental constraints imposed by the Ward identities and Q-limit Ward identity are indeed satisfied.

  7. Perspectives on Cybersecurity Information Sharing among Multiple Stakeholders Using a Decision-Theoretic Approach.

    Science.gov (United States)

    He, Meilin; Devine, Laura; Zhuang, Jun

    2017-08-11

    The government, private sectors, and others users of the Internet are increasingly faced with the risk of cyber incidents. Damage to computer systems and theft of sensitive data caused by cyber attacks have the potential to result in lasting harm to entities under attack, or to society as a whole. The effects of cyber attacks are not always obvious, and detecting them is not a simple proposition. As the U.S. federal government believes that information sharing on cybersecurity issues among organizations is essential to safety, security, and resilience, the importance of trusted information exchange has been emphasized to support public and private decision making by encouraging the creation of the Information Sharing and Analysis Center (ISAC). Through a decision-theoretic approach, this article provides new perspectives on ISAC, and the advent of the new Information Sharing and Analysis Organizations (ISAOs), which are intended to provide similar benefits to organizations that cannot fit easily into the ISAC structure. To help understand the processes of information sharing against cyber threats, this article illustrates 15 representative information sharing structures between ISAC, government, and other participating entities, and provide discussions on the strategic interactions between different stakeholders. This article also identifies the costs of information sharing and information security borne by different parties in this public-private partnership both before and after cyber attacks, as well as the two main benefits. This article provides perspectives on the mechanism of information sharing and some detailed cost-benefit analysis. © 2017 Society for Risk Analysis.

  8. Combination of real options and game-theoretic approach in investment analysis

    Science.gov (United States)

    Arasteh, Abdollah

    2016-02-01

    Investments in technology create a large amount of capital investments by major companies. Assessing such investment projects is identified as critical to the efficient assignment of resources. Viewing investment projects as real options, this paper expands a method for assessing technology investment decisions in the linkage existence of uncertainty and competition. It combines the game-theoretic models of strategic market interactions with a real options approach. Several key characteristics underlie the model. First, our study shows how investment strategies rely on competitive interactions. Under the force of competition, firms hurry to exercise their options early. The resulting "hurry equilibrium" destroys the option value of waiting and involves violent investment behavior. Second, we get best investment policies and critical investment entrances. This suggests that integrating will be unavoidable in some information product markets. The model creates some new intuitions into the forces that shape market behavior as noticed in the information technology industry. It can be used to specify best investment policies for technology innovations and adoptions, multistage R&D, and investment projects in information technology.

  9. An Information-Theoretic Approach for Energy-Efficient Collaborative Tracking in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Arienzo Loredana

    2010-01-01

    Full Text Available The problem of collaborative tracking of mobile nodes in wireless sensor networks is addressed. By using a novel metric derived from the energy model in LEACH (W.B. Heinzelman, A.P. Chandrakasan and H. Balakrishnan, Energy-Efficient Communication Protocol for Wireless Microsensor Networks, in: Proceedings of the 33rd Hawaii International Conference on System Sciences (HICSS '00, 2000 and aiming at an efficient resource solution, the approach adopts a strategy of combining target tracking with node selection procedures in order to select informative sensors to minimize the energy consumption of the tracking task. We layout a cluster-based architecture to address the limitations in computational power, battery capacity and communication capacities of the sensor devices. The computation of the posterior Cramer-Rao bound (PCRB based on received signal strength measurements has been considered. To track mobile nodes two particle filters are used: the bootstrap particle filter and the unscented particle filter, both in the centralized and in the distributed manner. Their performances are compared with the theoretical lower bound PCRB. To save energy, a node selection procedure based on greedy algorithms is proposed. The node selection problem is formulated as a cross-layer optimization problem and it is solved using greedy algorithms.

  10. Theoretical simulations on the antioxidant mechanism of naturally occurring flavonoid: A DFT approach

    Energy Technology Data Exchange (ETDEWEB)

    Praveena, R. [Department of Chemistry, Bannari Amman Institute of Technology, Sathyamangalam, Erode, Tamil Nadu (India); Sadasivam, K. [Department of Physics, Bannari Amman Institute of Technology, Sathyamangalam, Erode, Tamil Nadu (India)

    2016-05-06

    Synthetic antioxidants such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are found to be toxic, hence non-carcinogenic naturally occurring radical scavengers especially flavonoids have gained considerable importance in the past two decades. In the present investigation, the radical scavenging activity of C-glycosyl flavonoids is evaluated using theoretical approach which could broaden its scope in therapeutic applications. Gas and solvent phase studies of structural and molecular characteristics of C-glycosyl flavonoid, isovitexin is investigated through hydrogen atom transfer mechanism (HAT), Electron transfer-proton transfer (ET–PT) and Sequential proton loss electron transfer (SPLET) by Density functional theory (DFT) using hybrid parameters. The computed values of the adiabatic ionization potential, electron affinity, hardness, softness, electronegativity and electrophilic index indicate that isovitexin possess good radical scavenging activity. The behavior of different –OH groups in polyphenolic compounds is assessed by considering electronic effects of the neighbouring groups and the overall geometry of molecule which in turn helps in analyzing the antioxidant capacity of the polyphenolic molecule. The studies indicate that the H–atom abstraction from 4’–OH site is preferred during the radical scavenging process. From Mulliken spin density analysis and FMOs, B–ring is found to be more delocalized center and capable of electron donation. Comparison of antioxidant activity of vitexin and isovitexin leads to the conclusion that isovitexin acts as a better radical scavenger. This is an evidence for the importance of position of glucose unit in the flavonoid.

  11. A machine learning approach to graph-theoretical cluster expansions of the energy of adsorbate layers

    Science.gov (United States)

    Vignola, Emanuele; Steinmann, Stephan N.; Vandegehuchte, Bart D.; Curulla, Daniel; Stamatakis, Michail; Sautet, Philippe

    2017-08-01

    The accurate description of the energy of adsorbate layers is crucial for the understanding of chemistry at interfaces. For heterogeneous catalysis, not only the interaction of the adsorbate with the surface but also the adsorbate-adsorbate lateral interactions significantly affect the activation energies of reactions. Modeling the interactions of the adsorbates with the catalyst surface and with each other can be efficiently achieved in the cluster expansion Hamiltonian formalism, which has recently been implemented in a graph-theoretical kinetic Monte Carlo (kMC) scheme to describe multi-dentate species. Automating the development of the cluster expansion Hamiltonians for catalytic systems is challenging and requires the mapping of adsorbate configurations for extended adsorbates onto a graphical lattice. The current work adopts machine learning methods to reach this goal. Clusters are automatically detected based on formalized, but intuitive chemical concepts. The corresponding energy coefficients for the cluster expansion are calculated by an inversion scheme. The potential of this method is demonstrated for the example of ethylene adsorption on Pd(111), for which we propose several expansions, depending on the graphical lattice. It turns out that for this system, the best description is obtained as a combination of single molecule patterns and a few coupling terms accounting for lateral interactions.

  12. Beyond (eco)design: current approaches to sustainable packaging design

    NARCIS (Netherlands)

    Wever, R.

    2014-01-01

    Packaging has always received a lot of attention within the field of design for sustainability. The classical approach has been to mainly focus on reducing the impact of the packaging. This approach stems from the ill-informed position that packaging is superfluous, or at best there only for marketi

  13. Beyond (eco)design: current approaches to sustainable packaging design

    NARCIS (Netherlands)

    Wever, R.

    2014-01-01

    Packaging has always received a lot of attention within the field of design for sustainability. The classical approach has been to mainly focus on reducing the impact of the packaging. This approach stems from the ill-informed position that packaging is superfluous, or at best there only for

  14. Mean field approaches for $\\Xi^-$ hypernuclei and current experimental data

    CERN Document Server

    Sun, T T; Sagawa, H; Schulze, H -J; Meng, J

    2016-01-01

    Motivated by the recently observed hypernucleus (Kiso event) $^{15}_{\\Xi}$C ($^{14}$N$+\\Xi^-$), we identify the state of this system theoretically within the framework of the relativistic-mean-field and Skyrme-Hartree-Fock models. The $\\Xi N$ interactions are constructed to reproduce the two possibly observed $\\Xi^-$ removal energies, $4.38\\pm 0.25$ MeV or $1.11\\pm 0.25$ MeV. The present result is preferable to be $^{14}{\\rm N}({\\rm g.s.})+\\Xi^-(1p)$, corresponding to the latter value.

  15. Theoretical and computational chemistry.

    Science.gov (United States)

    Meuwly, Markus

    2010-01-01

    Computer-based and theoretical approaches to chemical problems can provide atomistic understanding of complex processes at the molecular level. Examples ranging from rates of ligand-binding reactions in proteins to structural and energetic investigations of diastereomers relevant to organo-catalysis are discussed in the following. They highlight the range of application of theoretical and computational methods to current questions in chemical research.

  16. Theoretical Antecedents of Standing at Work: An Experience Sampling Approach Using the Theory of Planned Behavior

    Directory of Open Access Journals (Sweden)

    M. Renée Umstattd Meyer

    2016-09-01

    Full Text Available Time spent sitting has been associated with an increased risk of diabetes, cancer, obesity, and mental health impairments. However, 75% of Americans spend most of their days sitting, with work-sitting accounting for 63% of total daily sitting time. Little research examining theory-based antecedents of standing or sitting has been conducted. This lack of solid groundwork makes it difficult to design effective intervention strategies to decrease sitting behaviors. Using the Theory of Planned Behavior (TPB as our theoretical lens to better understand factors related with beneficial standing behaviors already being practiced, we examined relationships between TPB constructs and time spent standing at work among “positive deviants” (those successful in behavior change. Experience sampling methodology (ESM, 4 times a day (midmorning, before lunch, afternoon, and before leaving work for 5 consecutive workdays (Monday to Friday, was used to assess employees’ standing time. TPB scales assessing attitude (α = 0.81–0.84, norms (α = 0.83, perceived behavioral control (α = 0.77, and intention (α = 0.78 were developed using recommended methods and collected once on the Friday before the ESM surveys started. ESM data are hierarchically nested, therefore we tested our hypotheses using multilevel structural equation modeling with Mplus. Hourly full-time university employees (n = 50; 70.6% female, 84.3% white, mean age = 44 (SD = 11, 88.2%in full-time staff positions with sedentary occupation types (time at desk while working ≥6 hours/day participated. A total of 871 daily surveys were completed. Only perceived behavioral control (β = 0.45, p < 0.05 was related with work-standing at the event-level (model fit: just fit; mediation through intention was not supported. This is the first study to examine theoretical antecedents of real-time work-standing in a naturalistic field setting among positive deviants. These relationships should be further

  17. Subjective evaluation and electroacoustic theoretical validation of a new approach to audio upmixing

    Science.gov (United States)

    Usher, John S.

    Audio signal processing systems for converting two-channel (stereo) recordings to four or five channels are increasingly relevant. These audio upmixers can be used with conventional stereo sound recordings and reproduced with multichannel home theatre or automotive loudspeaker audio systems to create a more engaging and natural-sounding listening experience. This dissertation discusses existing approaches to audio upmixing for recordings of musical performances and presents specific design criteria for a system to enhance spatial sound quality. A new upmixing system is proposed and evaluated according to these criteria and a theoretical model for its behavior is validated using empirical measurements. The new system removes short-term correlated components from two electronic audio signals using a pair of adaptive filters, updated according to a frequency domain implementation of the normalized-least-means-square algorithm. The major difference of the new system with all extant audio upmixers is that unsupervised time-alignment of the input signals (typically, by up to +/-10 ms) as a function of frequency (typically, using a 1024-band equalizer) is accomplished due to the non-minimum phase adaptive filter. Two new signals are created from the weighted difference of the inputs, and are then radiated with two loudspeakers behind the listener. According to the consensus in the literature on the effect of interaural correlation on auditory image formation, the self-orthogonalizing properties of the algorithm ensure minimal distortion of the frontal source imagery and natural-sounding, enveloping reverberance (ambiance) imagery. Performance evaluation of the new upmix system was accomplished in two ways: Firstly, using empirical electroacoustic measurements which validate a theoretical model of the system; and secondly, with formal listening tests which investigated auditory spatial imagery with a graphical mapping tool and a preference experiment. Both electroacoustic

  18. On the electric dipole moments of small sodium clusters from different theoretical approaches

    Energy Technology Data Exchange (ETDEWEB)

    Aguado, Andres, E-mail: aguado@metodos.fam.cie.uva.es [Departamento de Fisica Teorica, Atomica, y Optica, Universidad de Valladolid (Spain); Largo, Antonio, E-mail: alargo@qf.uva.es [Departamento de Quimica Fisica y Quimica Inorganica, Universidad de Valladolid (Spain); Vega, Andres, E-mail: vega@fta.uva.es [Departamento de Fisica Teorica, Atomica, y Optica, Universidad de Valladolid (Spain); Balbas, Luis Carlos, E-mail: balbas@fta.uva.es [Departamento de Fisica Teorica, Atomica, y Optica, Universidad de Valladolid (Spain)

    2012-05-03

    Graphical abstract: The dipole moments and polarizabilities of a few isomers of sodium clusters of selected sizes (n = 13, 14, 16) are calculated using density functional theory methods as well as ab initio MP2, CASSCF, and MR-CI methods. Among the density functional approaches, we consider the usual local density and generalized gradient approximations, as well as a recent van der Waals self-consistent functional accounting for non-local dispersion interactions. Highlights: Black-Right-Pointing-Pointer Dipole moment and polarizability of sodium clusters from DFT and ab initio methods. Black-Right-Pointing-Pointer New van der Waals selfconsistent implementation of non-local dispersion interactions. Black-Right-Pointing-Pointer New starting isomeric geometries from extensive search of global minimum structures. Black-Right-Pointing-Pointer Good agreement with recent experiments at cryogenic temperatures. - Abstract: The dipole moments of Na{sub n} clusters in the size range 10 < n < 20, recently measured at very low temperature (20 K), are much smaller than predicted by standard density functional methods. On the other hand, the calculated static dipole polarizabilities in that range of sizes deviate non-systematically from the measured ones, depending on the employed first principles approach. In this work we calculate the dipole moments and polarizabilities of a few isomers of Na{sub n} clusters of selected sizes (n = 13, 14, 16), obtained recently through an extensive unbiased search of the global minimum structures, and using density functional theory methods as well as ab initio MP2, CASSCF, and MR-CI methods. Among the density functional approaches, we consider the usual local density and generalized gradient approximations, as well as a recent van der Waals self-consistent functional accounting for non-local dispersion interactions. Both non-local pseudopotentials and all-electron implementations are employed and compared in order to assess the possible

  19. HEADROOM APPROACH TO DEVICE DEVELOPMENT: CURRENT AND FUTURE DIRECTIONS

    OpenAIRE

    Girling, A; Lilford, R; Cole, A; Young, T

    2015-01-01

    OBJECTIVES: The headroom approach to medical device development relies on the estimation of a value-based price ceiling at different stages of the development cycle. Such price-ceilings delineate the commercial opportunities for new products in many healthcare systems. We apply a simple model to obtain critical business information as the product proceeds along a development pathway, and indicate some future directions for the development of the approach. METHODS: Health economic modelling in...

  20. Sexuality Education for Young People: A Theoretically Integrated Approach from Australia

    Science.gov (United States)

    Goldman, Juliette D. G.

    2010-01-01

    Background: Teachers of sexuality education can often be uncertain about what theoretical basis and pedagogical strategies to use in their teaching. Sexuality educational programmes designed by teachers can often show few evident theoretical principles that have been applied in its construction. Thus, there seems to be a dearth of evidence of ways…

  1. Auroral current systems in Saturn's magnetosphere: comparison of theoretical models with Cassini and HST observations

    Directory of Open Access Journals (Sweden)

    S. W. H. Cowley

    2008-09-01

    Full Text Available The first simultaneous observations of fields and plasmas in Saturn's high-latitude magnetosphere and UV images of the conjugate auroral oval were obtained by the Cassini spacecraft and the Hubble Space Telescope (HST in January 2007. These data have shown that the southern auroral oval near noon maps to the dayside cusp boundary between open and closed field lines, associated with a major layer of upward-directed field-aligned current (Bunce et al., 2008. The results thus support earlier theoretical discussion and quantitative modelling of magnetosphere-ionosphere coupling at Saturn (Cowley et al., 2004, that suggests the oval is produced by electron acceleration in the field-aligned current layer required by rotational flow shear between strongly sub-corotating flow on open field lines and near-corotating flow on closed field lines. Here we quantitatively compare these modelling results (the "CBO" model with the Cassini-HST data set. The comparison shows good qualitative agreement between model and data, the principal difference being that the model currents are too small by factors of about five, as determined from the magnetic perturbations observed by Cassini. This is suggested to be principally indicative of a more highly conducting summer southern ionosphere than was assumed in the CBO model. A revised model is therefore proposed in which the height-integrated ionospheric Pedersen conductivity is increased by a factor of four from 1 to 4 mho, together with more minor adjustments to the co-latitude of the boundary, the flow shear across it, the width of the current layer, and the properties of the source electrons. It is shown that the revised model agrees well with the combined Cassini-HST data, requiring downward acceleration of outer magnetosphere electrons through a ~10 kV potential in the current layer at the open-closed field line boundary to produce an auroral oval of ~1° width with UV emission intensities of a few tens of kR.

  2. A Graph Theoretic Approach for Hydraulic Fracturing and Wellbore Leakage Risk Modeling

    Science.gov (United States)

    Glosser, D.; Rose, K.; Bauer, J. R.; Warner, T.

    2016-12-01

    Recent large scale development of unconventional formations for fossil energy has raised concerns over the potential for fluid leakage between subsurface systems and wellbores. This is particularly true in regions with extensive drilling history, where spatial densities of wellbores are higher, and where significant uncertainties in the location and mechanical integrity of such wellbores exist. The generation of induced fracture networks during hydraulic fracturing may increase subsurface connectivity, and create the potential for unwanted fluid migration between operational and legacy wellbores and subsurface fracture networks. We present a graph theoretic approach for identifying geospatial regions and wellbores at increased risk for subsurface connectivity based on wellbore proximity and local geologic characteristics. The algorithm transforms user inputted geospatial data (geologic and wellbore x,y,z) to graph structure, where wellbores are represented as nodes, and where potential overlapping fracture network zones are represented as edges. The algorithm can be used to complement existing fracture models to better account for the reach of induced fractures, and to identify spatial extents at increased risk for unwanted subsurface connectivity. Additionally, the model can be used to identify regions in need of geophysical detection methods for locating undocumented wells. As a result, the method can be part of a cumulative strategy to reduce uncertainty inherent to combined geologic and engineered systems. The algorithm has been successfully tested against a known leakage scenario in Pennsylvania. In addition to identifying wells associated with the leakage event, the algorithm identified two other higher risk networks in the region. The algorithm output provides valuable information for industry to develop environmentally safe drilling and injection plans; and for regulators to identify specific wellbores at greater risk for leakage, and to develop targeted

  3. A novel approach for absolute radar calibration: formulation and theoretical validation

    Directory of Open Access Journals (Sweden)

    C. Merker

    2015-06-01

    Full Text Available The theoretical framework of a novel approach for absolute radar calibration is presented and its potential analysed by means of synthetic data to lay out a solid basis for future practical application. The method presents the advantage of an absolute calibration with respect to the directly measured reflectivity, without needing a previously calibrated reference device. It requires a setup comprising three radars: two devices oriented towards each other, measuring reflectivity along the same horizontal beam and operating within a strongly attenuated frequency range (e.g. K or X band, and one vertical reflectivity and drop size distribution (DSD profiler below this connecting line, which is to be calibrated. The absolute determination of the calibration factor is based on attenuation estimates. Using synthetic, smooth and geometrically idealised data, calibration is found to perform best using homogeneous precipitation events with rain rates high enough to ensure a distinct attenuation signal (reflectivity above ca. 30 dBZ. Furthermore, the choice of the interval width (in measuring range gates around the vertically pointing radar, needed for attenuation estimation, is found to have an impact on the calibration results. Further analysis is done by means of synthetic data with realistic, inhomogeneous precipitation fields taken from measurements. A calibration factor is calculated for each considered case using the presented method. Based on the distribution of the calculated calibration factors, the most probable value is determined by estimating the mode of a fitted shifted logarithmic normal distribution function. After filtering the data set with respect to rain rate and inhomogeneity and choosing an appropriate length of the considered attenuation path, the estimated uncertainty of the calibration factor is of the order of 1 to 11 %, depending on the chosen interval width. Considering stability and accuracy of the method, an interval of

  4. Current approaches to model extracellular electrical neural microstimulation

    Directory of Open Access Journals (Sweden)

    Sébastien eJoucla

    2014-02-01

    Full Text Available Nowadays, high-density microelectrode arrays provide unprecedented possibilities to precisely activate spatially well-controlled central nervous system (CNS areas. However, this requires optimizing stimulating devices, which in turn requires a good understanding of the effects of microstimulation on cells and tissues. In this context, modeling approaches provide flexible ways to predict the outcome of electrical stimulation in terms of CNS activation. In this paper, we present state-of-the-art modeling methods with sufficient details to allow the reader to rapidly build numerical models of neuronal extracellular microstimulation. These include 1 the computation of the electrical potential field created by the stimulation in the tissue, and 2 the response of a target neuron to this field. Two main approaches are described: First we describe the classical hybrid approach that combines the finite element modeling of the potential field with the calculation of the neuron’s response in a cable equation framework (compartmentalized neuron models. Then, we present a whole finite element approach allows the simultaneous calculation of the extracellular and intracellular potentials, by representing the neuronal membrane with a thin-film approximation. This approach was previously introduced in the frame of neural recording, but has never been implemented to determine the effect of extracellular stimulation on the neural response at a sub-compartment level. Here, we show on an example that the latter modeling scheme can reveal important sub-compartment behavior of the neural membrane that cannot be resolved using the hybrid approach. The goal of this paper is also to describe in detail the practical implementation of these methods to allow the reader to easily build new models using standard software packages. These modeling paradigms, depending on the situation, should help build more efficient high-density neural prostheses for CNS rehabilitation.

  5. The chemical effects of the Martian environment on power system component materials: A theoretical approach

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Davis, M.E.; Gaier, J.R. [Lewis Research Center, Cleveland, OH (United States)

    1994-09-01

    In the foreseeable future, an expedition may be undertaken to explore the planet Mars. Some of the power source options being considered for such a mission are photovoltaics, regenerative fuel cells and nuclear reactors. In addition to electrical power requirements, environmental conditions en route to Mars, in the planetary orbit and on the Martian surface must be simulated and studied in order to anticipate and solve potential problems. Space power systems components such as photovoltaic arrays, radiators, and solar concentrators may be vulnerable to degradation in the Martian environment. Natural characteristics of Mars which may pose a threat to surface power systems include high velocity winds, dust, ultraviolet radiation, large daily variations in temperature, reaction to components of the soil, atmosphere and atmospheric condensates as well as synergistic combinations. Most of the current knowledge of the characteristics of the Martian atmosphere and soil composition was obtained from the Viking 1 and 2 missions in 1976. This paper presents a theoretical study used to assess the effects of the Martian atmospheric conditions on the power systems components. A computer program written at NASA Lewis Research Center in 1961 to 1962 for combustion research that uses a free-energy minimization technique was used to calculate chemical equilibrium for assigned thermodynamic states of temperature and pressure. The power system component materials selected for this study include: Silicon dioxide, silicon, carbon, copper, and titanium. Combinations of environments and materials considered in this study include: (1) Mars atmosphere with power surface material, (2) Mars atmosphere and dust component with power surface material, (3) Mars atmosphere and hydrogen peroxide or superoxide with power system material.

  6. The chemical effects of the Martian environment on power system component materials: A theoretical approach

    Science.gov (United States)

    Perez-Davis, Marla E.; Gaier, James R.

    1990-01-01

    In the foreseeable future, an expedition may be undertaken to explore the planet Mars. Some of the power source options being considered for such a mission are photovoltaics, regenerative fuel cells and nuclear reactors. In addition to electrical power requirements, environmental conditions en route to Mars, in the planetary orbit and on the Martian surface must be simulated and studied in order to anticipate and solve potential problems. Space power systems components such as photovoltaic arrays, radiators, and solar concentrators may be vulnerable to degradation in the Martian environment. Natural characteristics of Mars which may pose a threat to surface power systems include high velocity winds, dust, ultraviolet radiation, large daily variation in temperature, reaction to components of the soil, atmosphere and atmospheric condensates as well as synergistic combinations. Most of the current knowledge of the characteristics of the Martian atmosphere and soil composition was obtained from the Viking 1 and 2 missions in 1976. A theoretical study is presented which was used to assess the effects of the Martian atmospheric conditions on the power systems components. A computer program written at NASA-Lewis for combustion research that uses a free energy minimization technique was used to calculate chemical equilibrium for assigned thermodynamic states of temperature and pressure. The power system component materials selected for this study include: silicon dioxide, silicon, carbon, copper, and titanium. Combinations of environments and materials considered include: (1) Mars atmosphere with power surface material, (2) Mars atmosphere and dust component with power surface material, and (3) Mars atmosphere and hydrogen peroxide or superoxide or superoxide with power system material. The chemical equilibrium calculations were performed at a composition ratio (oxidant to reactant) of 100. The temperature for the silicon dioxide material and silicon, which simulate

  7. The Intertemporal Approach to the Current Account: Evidence for Chile

    Directory of Open Access Journals (Sweden)

    Sergio A. Salas Landeau

    2002-03-01

    Full Text Available This paper studies the existence of "excess" current-account imbalances in Chile in the 1960-1999 period. This phenomenon is modelled using present value tests that allow for variable interest rates and exchange rate fluctuations. Despite its simplicity, most of the observed imbalances in the current account are accounted for by the model. Results suggest that using models where agents behave as forward-looking rational agents, is a valid framework. Moreover, the analysis highlights the rel-evance of variable interest rates and exchange rates. Results also imply that capital controls, that were widely used in the period under study, were not effective.

  8. A Methodological Demonstration of Set-theoretical Approach to Social Media Maturity Models Using Necessary Condition Analysis

    DEFF Research Database (Denmark)

    Lasrado, Lester Allan; Vatrapu, Ravi; Andersen, Kim Normann

    2016-01-01

    Despite being widely accepted and applied across research domains, maturity models have been criticized for lacking academic rigor, especially methodologically rigorous and empirically grounded or tested maturity models are quite rare. Attempting to close this gap, we adopt a set-theoretic approach...

  9. An algorithmic and information-theoretic approach to multimetric index construction

    Science.gov (United States)

    Schoolmaster, Donald R.; Grace, James B.; Schweiger, E. William; Guntenspergen, Glenn R.; Mitchell, Brian R.; Miller, Kathryn M.; Little, Amanda M.

    2013-01-01

    The use of multimetric indices (MMIs), such as the widely used index of biological integrity (IBI), to measure, track, summarize and infer the overall impact of human disturbance on biological communities has been steadily growing in recent years. Initially, MMIs were developed for aquatic communities using pre-selected biological metrics as indicators of system integrity. As interest in these bioassessment tools has grown, so have the types of biological systems to which they are applied. For many ecosystem types the appropriate biological metrics to use as measures of biological integrity are not known a priori. As a result, a variety of ad hoc protocols for selecting metrics empirically has developed. However, the assumptions made by proposed protocols have not be explicitly described or justified, causing many investigators to call for a clear, repeatable methodology for developing empirically derived metrics and indices that can be applied to any biological system. An issue of particular importance that has not been sufficiently addressed is the way that individual metrics combine to produce an MMI that is a sensitive composite indicator of human disturbance. In this paper, we present and demonstrate an algorithm for constructing MMIs given a set of candidate metrics and a measure of human disturbance. The algorithm uses each metric to inform a candidate MMI, and then uses information-theoretic principles to select MMIs that capture the information in the multidimensional system response from among possible MMIs. Such an approach can be used to create purely empirical (data-based) MMIs or can, optionally, be influenced by expert opinion or biological theory through the use of a weighting vector to create value-weighted MMIs. We demonstrate the algorithm with simulated data to demonstrate the predictive capacity of the final MMIs and with real data from wetlands from Acadia and Rocky Mountain National Parks. For the Acadia wetland data, the algorithm identified

  10. Current Approaches to the Understanding of Early Infantile Autism.

    Science.gov (United States)

    Rickman, David L.

    This review of the literature provides summaries of the genetic, neurophysiological, and biochemical approaches to understanding autism, with special reference to neuroanatomic, cognitive, and neuropsychological studies of this disorder. Available instruments for the assessment of autism and various treatment alternatives including drug therapy,…

  11. Automatic object recognition: critical issues and current approaches

    Science.gov (United States)

    Sadjadi, Firooz A.

    1991-08-01

    Automatic object recognition, with its diverse applications in numerous fields of science and technology, is permeating many aspects of military and civilian industries. This paper gives an overview of the issues confronting the automatic object recognition field and the approaches being used to address these issues.

  12. Current Approaches to Improving Access to Government Documents.

    Science.gov (United States)

    Turner, Carol; Latta, Ann

    Based on the responses of 77 Association of Research Libraries (ARL) member libraries to a December 1986 survey of 106 ARL libraries (a 73% response rate), this report profiles the current state of bibliographic access to federal publications. Following a brief discussion of survey background and methodology, a summary of survey results indicates…

  13. Methodological Approaches in Conducting Overviews: Current State in HTA Agencies

    Science.gov (United States)

    Pieper, Dawid; Antoine, Sunya-Lee; Morfeld, Jana-Carina; Mathes, Tim; Eikermann, Michaela

    2014-01-01

    Objectives: Overviews search for reviews rather than for primary studies. They might have the potential to support decision making within a shorter time frame by reducing production time. We aimed to summarize available instructions for authors intending to conduct overviews as well as the currently applied methodology of overviews in…

  14. Experimental typography : reviewing the modernist and the current approaches

    OpenAIRE

    Makal, Eray

    1993-01-01

    Ankara : The Department of Graphic Design and Institute of Fine Arts, Bilkent Univ., 1993. Thesis (Master's) -- Bilkent University, 1993. Includes bibliographical references leaves 65-66. The intention of this study is to evaluate the experimental typography within the history of graphic design by taking in consideration of two epochs. The Modernist and The Current. Makal, Eray M.S.

  15. Modeling left and right atrial contributions to the ECG: A dipole-current source approach.

    Science.gov (United States)

    Jacquemet, Vincent

    2015-10-01

    This paper presents the mathematical formulation, the numerical validation and several illustrations of a forward-modeling approach based on dipole-current sources to compute the contribution of a part of the heart to the electrocardiogram (ECG). Clinically relevant applications include identifying in the ECG the contributions from the right and the left atrium. In a Courtemanche-based monodomain computer model of the atria and torso, 1000 dipoles distributed throughout the atrial mid-myocardium are found to be sufficient to reproduce body surface potential maps with a relative error approach enables fast offline computation of the ECG contribution of any anatomical part of the atria by applying the principle of superposition to the dipole sources. In the presence of a right-left activation delay (sinus rhythm), pulmonary vein isolation (sinus rhythm) or left-right differences in refractory period (atrial fibrillation), the decomposition of the ECG is shown to help interpret ECG morphology in relation to the atrial substrate. These tools provide a theoretical basis for a deeper understanding of the genesis of the P wave or fibrillatory waves in normal and pathological cases.

  16. Quantitative Myocardial Perfusion with Dynamic Contrast-Enhanced Imaging in MRI and CT: Theoretical Models and Current Implementation

    Directory of Open Access Journals (Sweden)

    G. J. Pelgrim

    2016-01-01

    Full Text Available Technological advances in magnetic resonance imaging (MRI and computed tomography (CT, including higher spatial and temporal resolution, have made the prospect of performing absolute myocardial perfusion quantification possible, previously only achievable with positron emission tomography (PET. This could facilitate integration of myocardial perfusion biomarkers into the current workup for coronary artery disease (CAD, as MRI and CT systems are more widely available than PET scanners. Cardiac PET scanning remains expensive and is restricted by the requirement of a nearby cyclotron. Clinical evidence is needed to demonstrate that MRI and CT have similar accuracy for myocardial perfusion quantification as PET. However, lack of standardization of acquisition protocols and tracer kinetic model selection complicates comparison between different studies and modalities. The aim of this overview is to provide insight into the different tracer kinetic models for quantitative myocardial perfusion analysis and to address typical implementation issues in MRI and CT. We compare different models based on their theoretical derivations and present the respective consequences for MRI and CT acquisition parameters, highlighting the interplay between tracer kinetic modeling and acquisition settings.

  17. Current Approaches for Management of Postpenetrating Keratoplasty Astigmatism

    Directory of Open Access Journals (Sweden)

    Sepehr Feizi

    2011-01-01

    Full Text Available A successful corneal graft requires both clarity and an acceptable refraction. A clear corneal graft may be an optical failure if high astigmatism limits visual acuity. Intraoperative measures to reduce postkeratoplasty astigmatism include round and central trephination of cornea with an adequate size, appropriate sutures with evenly distributed tension, and perfect graft-host apposition. Suture manipulation has been described for minimising early postoperative astigmatism. If significant astigmatism remains after suture removal, which cannot be corrected by optical means, then further surgical procedures containing relaxing incisions, compression sutures, laser refractive surgery, insertion of intrastromal corneal ring segments, wedge resection, and toric intraocular lens implantation can be performed. When astigmatism cannot be reduced using one or more abovementioned approaches, repeat penetrating keratoplasty should inevitably be considered. However, none of these techniques has emerged as an ideal one, and corneal surgeons may require combining two or more approaches to exploit the maximum advantages.

  18. Current treatment approaches in patients with ankylosing spondylitis

    Directory of Open Access Journals (Sweden)

    Bilal Elbey

    2015-03-01

    Full Text Available Ankylosing spondylitis (AS is a chronic, inflammatory, rheumatic disease that mainly affects sacroiliac joints and spine. AS predominantly occurs more often in males and typically begins in the second or third decade. The mainstay of therapy in AS are nonsteroidal anti-inflammatory drugs, which reduce inflammation and pain. Disease modifying antirheumatic drugs (DMARD did not have enough evidence to prove their effect in AS treatment. The use of DMARD may not sufficient to improve the treatment and symptoms. Currently, TNF-blockers such as, Golimumab Etanersept Adalimumab İnfliksimab have promising results in the treatment of AS. TNF-blockers improve the clinical signs and symptoms, and improve the patients’ physical function and quality of life. This manuscript is focused that Current pharmacological treatments in patients with ankylosing spondylitis.

  19. RESEARCH ON SOME THEORETICAL PROBLEMS OF MAP DATA HANDLING USING FRACTAL APPROACH

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Some theoretical problems of fractal geographical map data handling are dis cussed and some new methods about fractal dimension introducing, developing, comparing and estimating are proposed in this paper.

  20. Explaining teacher-student interactions in early childhood: an interpersonal theoretical approach

    NARCIS (Netherlands)

    Thijs, J.; Koomen, H.; Roorda, D.; ten Hagen, J.

    2011-01-01

    The present study used an interpersonal theoretical perspective to examine the interactions between Dutch teachers and kindergartners. Interpersonal theory provides explanations for dyadic interaction behaviors by stating that complementary behaviors (dissimilar in terms of control, and similar in t

  1. Theoretical-game estimate of radiosystem's efficiency based on entropy approach

    OpenAIRE

    Marigodov, V. K.

    2011-01-01

    Theoretical-game synthesis of radio communications system in a conflict situation of interaction between radio communications system and radio masking system operators taking into consideration information limitations that are imposed on differential entropies of players’ mixed strategies.

  2. Modification of Current Feedback Strategies: A Text Synthesis Approach.

    Science.gov (United States)

    1984-03-01

    f c o lorad I Technic Report No. 127 This research was aponsored byiwtut ot Cogniive Science The Air Force Office of Scienlbc Uriverulty of Cooado...SYNTHESIS APPROACH(UA COLORADO ANIA AT BOXLDEN INST OF COONITXE SCIENCE P LANGEB ET AL MAN 84 N6 SIID AORT-408 FS-304 / /0 N EA-1216 OIIATOh E CR E...ADDRESS 10. PROGRAM ELEMENT, PROJECT. TASK AREA & WORK( UNIT NUMIERS Institute of Cognitive Science University of Colorado 61103F Boulder, CO 80309

  3. Current approaches and problems in social crime prevention

    OpenAIRE

    Vuković, Slaviša

    2011-01-01

    In this paper the topic of consideration focuses on current methods and forms of implementation social crime prevention, as well as problems that often arise in practice during its implementation. This is one of the most important areas in crime prevention, which is also known as crime prevention through social development, and often includes legal activities of state and non-state actors aimed at preventing delinquency of children and minors through the weakening and, if possible, eliminatin...

  4. Direct current stimulation : new approach to enhancing heavy oil production

    Energy Technology Data Exchange (ETDEWEB)

    Whittle, J.K. [Electro-Petroleum Inc., Wayne, PA (United States); Hill, D.G. [Southern California Univ., Los Angeles, CA (United States)

    2006-07-01

    The limited recovery of heavy crude oil can be attributed to the high viscosity of the liquids in the oil reservoirs. A viable technology has been lacking for the economic recovery of heavy oil. This paper discussed the advantages of direct current electrical stimulation or electro-enhanced oil recovery (EEOR). The paper outlined the advantages, including data produced from field demonstrations as well as the results of recent laboratory studies. The paper provided a historical and electro-chemical background of EEOR. Field operations that were discussed included electric field maps and a comparison of direct current versus alternating current electrical power. A series of EEOR field demonstrations were presented for the Santa Maria basin in California and the eastern Alberta plains. The paper also discussed produced fluid chemical changes and electro-osmosis and effective permeability. Last, the paper provided a comparison of EEOR to other existing and emerging technologies including steam flood; surfactant flood; co-solvent flood; carbon dioxide flood; and fire flood. It was concluded that the biggest EEOR limitation is its limited field application portfolio. EEOR has produced encouraging field demonstrations to date and has facilitated beneficial chemical changes in the produced fluids. 26 refs., 5 tabs., 10 figs.

  5. New theoretical approach to the RF-dynamics of soft magnetic FeTaN films for CMOS components

    Energy Technology Data Exchange (ETDEWEB)

    Seemann, K. E-mail: klaus.seemann@imf.fzk.de; Leiste, H.; Bekker, V

    2004-07-01

    A new approach to a theoretical description of the RF-behavior of magnetic films possessing an in-plane uniaxial anisotropy was carried out by combining the Landau-Lifschitz and Maxwell equations for modeling spin dynamics and eddy current loss, respectively, to a comprehensive mathematical expression. Because of that, it is possible to compute the complex permeability in a wide frequency range. The theory was utilized to describe the dynamic response of soft magnetic FeTaN films deposited by reactive RF-magnetron sputtering for microelectronic RF-components like micro-inductors. A 6-inch target consisting of Fe{sub 90}Ta{sub 10} was used to grow the films on oxidized silicon substrates with a titanium seed layer for better film adhesion. The concentration of nitrogen could be adjusted by a flow control system. With regard to aluminum CMOS processes carried out at around 400 deg. C and to induce an in-plane uniaxial anisotropy the films were annealed at this temperature in a static magnetic field of 50 mT. It was found that the nitrogen content of the films in conjunction with the needed temperatures played an important role to obtain a marked uniaxial anisotropy in the film plane. Consequently, an annealing procedure had to be elaborated to obtain the in-plane uniaxial anisotropy at the relevant CMOS temperatures. For the application in RF-components and in view of eddy current losses, the magnetic FeTaN films were investigated for different thicknesses which delivered information that slipped in a multilayer design. Multilayers, i.e. magnetic single layers with a sufficient thickness separated by insulating inter-layers made of Si{sub 3}N{sub 4}, were necessary to decrease eddy currents at radio frequencies. This led to an improved frequency behavior. The introduced theory was then compared satisfactorily with the frequency-dependent permeability of FeTaN films of various thickness. It is concluded that an optimum film thickness can be roughly calculated in

  6. Current approaches in evolution: from molecules to cells and organisms.

    Science.gov (United States)

    Thattai, Mukund; Peisajovich, Sergio G

    2014-11-01

    This is an exciting time to be an evolutionary biologist. Indeed, it is difficult to keep up with all the studies that fall under the broad category of "Evolution" since they span species, traits, and scales of organization. This special issue gives a flavor of exciting new approaches in evolutionary biology, but also emphasizes universal themes. The reviews contained here discuss important aspects of molecular evolution at multiple scales, from individual proteins to complex regulatory networks, as well as from unicellular organisms to macroscopic traits in animals. Though the model systems are diverse, the issues addressed are fundamental: the origin of evolutionary novelties, and the forces that drive them to fixation.

  7. Current approach for urinary system stone disease in pregnant women

    Directory of Open Access Journals (Sweden)

    Orcun Celik

    2016-01-01

    Full Text Available Urinary system stones can be classified according to size, location, X-ray characteristics, aetiology of formation, composition, and risk of recurrence. Especially urolithiasis during pregnancy is a diagnostic and therapeutic challenge. In most cases, it becomes symptomatic in the second or third trimester. Diagnostic options in pregnant women are limited due to the possible teratogenic, carcinogenic, and mutagenic risk of foetal radiation exposure. Clinical management of a pregnant urolithiasis patient is complex and demands close collaboration between patient, obstetrician and urologist. We would like to review current diagnosis and treatment modalities of stone disease of pregnant woman.

  8. Current approach for urinary system stone disease in pregnant women.

    Science.gov (United States)

    Celik, Orcun; Türk, Hakan; Cakmak, Ozgur; Budak, Salih; Ekin, Rahmi Gokhan; Keskin, Mehmet Zeynel; Yildiz, Guner; Ilbey, Yusuf Ozlem

    2016-01-14

    Urinary system stones can be classified according to size, location, X-ray characteristics, aetiology of formation, composition, and risk of recurrence. Especially urolithiasis during pregnancy is a diagnostic and therapeutic challenge. In most cases, it becomes symptomatic in the second or third trimester. Diagnostic options in pregnant women are limited due to the possible teratogenic, carcinogenic, and mutagenic risk of foetal radiation exposure. Clinical management of a pregnant urolithiasis patient is complex and demands close collaboration between patient, obstetrician and urologist. We would like to review current diagnosis and treatment modalities of stone disease of pregnant woman.

  9. A theoretical and experimental approach for correlating nanoparticle structure and electrocatalytic activity.

    Science.gov (United States)

    Anderson, Rachel M; Yancey, David F; Zhang, Liang; Chill, Samuel T; Henkelman, Graeme; Crooks, Richard M

    2015-05-19

    The objective of the research described in this Account is the development of high-throughput computational-based screening methods for discovery of catalyst candidates and subsequent experimental validation using appropriate catalytic nanoparticles. Dendrimer-encapsulated nanoparticles (DENs), which are well-defined 1-2 nm diameter metal nanoparticles, fulfill the role of model electrocatalysts. Effective comparison of theory and experiment requires that the theoretical and experimental models map onto one another perfectly. We use novel synthetic methods, advanced characterization techniques, and density functional theory (DFT) calculations to approach this ideal. For example, well-defined core@shell DENs can be synthesized by electrochemical underpotential deposition (UPD), and the observed deposition potentials can be compared to those calculated by DFT. Theory is also used to learn more about structure than can be determined by analytical characterization alone. For example, density functional theory molecular dynamics (DFT-MD) was used to show that the core@shell configuration of Au@Pt DENs undergoes a surface reconstruction that dramatically affects its electrocatalytic properties. A separate Pd@Pt DENs study also revealed reorganization, in this case a core-shell inversion to a Pt@Pd structure. Understanding these types of structural changes is critical to building correlations between structure and catalytic function. Indeed, the second principal focus of the work described here is correlating structure and catalytic function through the combined use of theory and experiment. For example, the Au@Pt DENs system described earlier is used for the oxygen reduction reaction (ORR) as well as for the electro-oxidation of formic acid. The surface reorganization predicted by theory enhances our understanding of the catalytic measurements. In the case of formic acid oxidation, the deformed nanoparticle structure leads to reduced CO binding energy and therefore

  10. Current approach in the diagnosis and management of panuveitis

    Directory of Open Access Journals (Sweden)

    Bansal Reema

    2010-01-01

    Full Text Available Panuveitis is a generalized inflammation of not only the whole of the uveal tract but also involves the retina and vitreous humor. It differs from other anatomical sites of inflammation in terms of causes as well as distribution. The common causes of panuveitis in our population are tuberculosis, Vogt-Koyanagi-Harada syndrome, sympathetic ophthalmia, Behcet′s disease and sarcoidosis. A large number of cases still remain idiopathic. A stepwise approach is essential while evaluating these patients to be able to identify and treat the disease timely and correctly. Ancillary tests can be appropriately applied once the anatomic site of inflammation is identified. An exhaustive approach comprising a full battery of tests is obsolete. Only specific tailored investigations are ordered as suggested by the preliminary clinical and ocular examination. The mainstay of the treatment of uveitis is corticosteroids. Immunosuppressive agents are administered if the inflammation is not adequately controlled with corticosteroids. One of the recent breakthroughs in the treatment of refractory uveitis includes the introduction of immunomodulating drugs: Tumor necrosis factor-alpha antagonist and Interferon-alpha. Vitrectomy has been used in uveitis for over a few decades for diagnostic and therapeutic purposes. When compared to other anatomical sites of inflammation, panuveitis has poor visual outcome due to more widespread inflammation. The side-effects of the chronic treatment that these patients receive cannot be overlooked and should be specifically monitored under the supervision of an internist with special interest in inflammatory diseases.

  11. Current Approaches in Implementing Citizen Science in the Classroom.

    Science.gov (United States)

    Shah, Harsh R; Martinez, Luis R

    2016-03-01

    Citizen science involves a partnership between inexperienced volunteers and trained scientists engaging in research. In addition to its obvious benefit of accelerating data collection, citizen science has an unexplored role in the classroom, from K-12 schools to higher education. With recent studies showing a weakening in scientific competency of American students, incorporating citizen science initiatives in the curriculum provides a means to address deficiencies in a fragmented educational system. The integration of traditional and innovative pedagogical methods to reform our educational system is therefore imperative in order to provide practical experiences in scientific inquiry, critical thinking, and problem solving for school-age individuals. Citizen science can be used to emphasize the recognition and use of systematic approaches to solve problems affecting the community.

  12. Ebola virus vaccines: an overview of current approaches.

    Science.gov (United States)

    Marzi, Andrea; Feldmann, Heinz

    2014-04-01

    Ebola hemorrhagic fever is one of the most fatal viral diseases worldwide affecting humans and nonhuman primates. Although infections only occur frequently in Central Africa, the virus has the potential to spread globally and is classified as a category A pathogen that could be misused as a bioterrorism agent. As of today there is no vaccine or treatment licensed to counteract Ebola virus infections. DNA, subunit and several viral vector approaches, replicating and non-replicating, have been tested as potential vaccine platforms and their protective efficacy has been evaluated in nonhuman primate models for Ebola virus infections, which closely resemble disease progression in humans. Though these vaccine platforms seem to confer protection through different mechanisms, several of them are efficacious against lethal disease in nonhuman primates attesting that vaccination against Ebola virus infections is feasible.

  13. Current Approaches in Implementing Citizen Science in the Classroom

    Directory of Open Access Journals (Sweden)

    Harsh R. Shah

    2015-12-01

    Full Text Available Citizen science involves a partnership between inexperienced volunteers and trained scientists engaging in research. In addition to its obvious benefit of accelerating data collection, citizen science has an unexplored role in the classroom, from K–12 schools to higher education. With recent studies showing a weakening in scientific competency of American students, incorporating citizen science initiatives in the curriculum provides a means to address deficiencies in a fragmented educational system. The integration of traditional and innovative pedagogical methods to reform our educational system is therefore imperative in order to provide practical experiences in scientific inquiry, critical thinking, and problem solving for school-age individuals. Citizen science can be used to emphasize the recognition and use of systematic approaches to solve problems affecting the community.

  14. Current approaches on viral infection: proteomics and functional validations

    Directory of Open Access Journals (Sweden)

    Jie eZheng

    2012-11-01

    Full Text Available Viruses could manipulate cellular machinery to ensure their continuous survival and thus become parasites of living organisms. Delineation of sophisticated host responses upon virus infection is a challenging task. It lies in identifying the repertoire of host factors actively involved in the viral infectious cycle and characterizing host responses qualitatively and quantitatively during viral pathogenesis. Mass spectrometry based proteomics could be used to efficiently study pathogen-host interactions and virus-hijacked cellular signaling pathways. Moreover, direct host and viral responses upon infection could be further investigated by activity based functional validation studies. These approaches involve drug inhibition of secretory pathway, immunofluorescence staining, dominant negative mutation of protein target, real time PCR, small interfering siRNA-mediated knockdown, and molecular cloning studies. In this way, functional validation could gain novel insights into the high-content proteomic dataset in an unbiased and comprehensive way.

  15. Epigenetic phenomena, chromatin dynamics, and gene expression. New theoretical approaches in the study of living systems.

    Science.gov (United States)

    Boi, Luciano

    2008-01-01

    This paper is aimed at exploring the genome at the level beyond that of DNA sequence alone. We stress the fact that the level of genes is not the sole "reality" in the living world, for there are different epigenetic processes that profoundly affect change in living systems. Moreover, epigenetics very likely influences the course of evolution and the unfolding of life. We further attempt to investigate how the genome is dynamically organized into the nuclear space within the cell. We mainly focus on analyses of higher order nuclear architecture and the dynamic interactions of chromatin with other nuclear components. We especially want to know how epigenetic phenomena influences genes expression and chromosome functions. The proper understanding of these processes require new concepts and approaches be introduced and developed. In particular, we think that research in biology has to shift from only describing molecular and local features of living systems to studying the regulatory networks of interactions among gene pathways, the folding and dynamics of chromatin structure and how environmental factors affects the behavior of organisms. There are essential components of biological information on living organisms which cannot be portrayed in the DNA sequence alone. In a post-genomic era, the importance of chromatin/epigenetic interface has become increasingly apparent. One of the purposes of current research should be to highlight the enormous impact of chromatin organization and dynamics on epigenetic phenomena, and, conversely, to emphasize the important role that epigenetic phenomena play in gene expression and cell regulation.

  16. Determination and controlling of grain structure of metals after laser incidence: Theoretical approach

    Science.gov (United States)

    Dezfoli, Amir Reza Ansari; Hwang, Weng-Sing; Huang, Wei-Chin; Tsai, Tsung-Wen

    2017-01-01

    There are serious questions about the grain structure of metals after laser melting and the ways that it can be controlled. In this regard, the current paper explains the grain structure of metals after laser melting using a new model based on combination of 3D finite element (FE) and cellular automaton (CA) models validated by experimental observation. Competitive grain growth, relation between heat flows and grain orientation and the effect of laser scanning speed on final micro structure are discussed with details. Grains structure after laser melting is founded to be columnar with a tilt angle toward the direction of the laser movement. Furthermore, this investigation shows that the grain orientation is a function of conduction heat flux at molten pool boundary. Moreover, using the secondary laser heat source (SLHS) as a new approach to control the grain structure during the laser melting is presented. The results proved that the grain structure can be controlled and improved significantly using SLHS. Using SLHS, the grain orientation and uniformity can be change easily. In fact, this method can help us to produce materials with different local mechanical properties during laser processing according to their application requirements.

  17. A THEORETICAL AND POLICY APPROACH OF CLUSTERS, AS SUPPORTING INNOVATION AND DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Dalina Maria Andrei

    2014-12-01

    Full Text Available The concept of Clusters seems to belong to the present whereas actually it is an old economic concept. Even classics (e.g. David Ricardo or old neoclassic (e.g. Alfred Marshall have still significant references for the today, whereas present produced enough favorable environment for. This paper will develop some of all references about, economic thinking, description and policy issues to be noted on. Moreover, the new need of clusters consists in the scenery that the economy exposes and preserves today. Risks, disadvantages and all that shadow such new current character and actor‟ are not only inherent, but keep their place in context. The specific cluster policy, in its turn, explicitly identifies what the national level‟s interests and the barriers of achieving those goals are and how cluster approach can help overcome these problems. It equally weights the relative merits of active intervention from the national level, versus framework conditions and facilitation, vis-à-vis theories and models.

  18. The Analysis of Theoretical Approaches to Identification of Factors of Regional Economic Growth

    Directory of Open Access Journals (Sweden)

    Kosyrieva Olena V.

    2016-05-01

    Full Text Available The article is devoted to the investigation of current approaches to identification of factors of economic growth in the regions. The theory of new economic geography based on works and studies of P. Krugman has been considered. There highlighted the key issues of regional economic growth requiring an in-depth studying and consideration in the elaboration of strategies for sustainable development of the regions. The views of leading domestic and foreign scholars as well as the OECD experts, the World Bank, the National Statistics Service of the United Kingdom and others on the main drivers of economic growth have been analyzed. On the basis of the study the factors of regional economic growth most commonly encountered in theory and practice have been generalized. It is proved that scientists and analysts most often classify as the factors of regional economic growth the following ones: those characterizing human potential, scientific-technical and innovative activity, management and institutional capacity. The factors less frequently correlated by specialists and scientists with the regional economic growth include: those characterizing the environment, business and sociopolitical factors, which is associated with difficulty of their quantification, but in any case does not diminish their importance.

  19. Current approaches and future directions in the treatment of leprosy

    Directory of Open Access Journals (Sweden)

    Worobec SM

    2012-08-01

    Full Text Available Sophie M WorobecDepartment of Dermatology, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USAAbstract: This review surveys current treatments and future treatment trends in leprosy from a clinical perspective. The World Health Organization provides a multidrug treatment regimen that targets the Mycobacterium leprae bacillus which causes leprosy. Several investigational drugs are available for the treatment of drug-resistant M. leprae. Future directions in leprosy treatment will focus on: the molecular signaling mechanism M. leprae uses to avoid triggering an immune response; prospective studies of the side effects experienced during multiple-drug therapy; recognition of relapse rates post-completion of designated treatments; combating multidrug resistance; vaccine development; development of new diagnostic tests; and the implications of the recent discovery of a genetically distinct leprosy-causing bacillus, Mycobacterium lepromatosis.Keywords: epidemiology, leprosy, Hansen’s disease, multidrug resistance, multidrug therapy

  20. Achieving behaviour change for detection of Lynch syndrome using the Theoretical Domains Framework Implementation (TDFI) approach: a study protocol.

    Science.gov (United States)

    Taylor, Natalie; Long, Janet C; Debono, Deborah; Williams, Rachel; Salisbury, Elizabeth; O'Neill, Sharron; Eykman, Elizabeth; Braithwaite, Jeffrey; Chin, Melvin

    2016-03-12

    Lynch syndrome is an inherited disorder associated with a range of cancers, and found in 2-5 % of colorectal cancers. Lynch syndrome is diagnosed through a combination of significant family and clinical history and pathology. The definitive diagnostic germline test requires formal patient consent after genetic counselling. If diagnosed early, carriers of Lynch syndrome can undergo increased surveillance for cancers, which in turn can prevent late stage cancers, optimise treatment and decrease mortality for themselves and their relatives. However, over the past decade, international studies have reported that only a small proportion of individuals with suspected Lynch syndrome were referred for genetic consultation and possible genetic testing. The aim of this project is to use behaviour change theory and implementation science approaches to increase the number and speed of healthcare professional referrals of colorectal cancer patients with a high-likelihood risk of Lynch syndrome to appropriate genetic counselling services. The six-step Theoretical Domains Framework Implementation (TDFI) approach will be used at two large, metropolitan hospitals treating colorectal cancer patients. Steps are: 1) form local multidisciplinary teams to map current referral processes; 2) identify target behaviours that may lead to increased referrals using discussion supported by a retrospective audit; 3) identify barriers to those behaviours using the validated Influences on Patient Safety Behaviours Questionnaire and TDFI guided focus groups; 4) co-design interventions to address barriers using focus groups; 5) co-implement interventions; and 6) evaluate intervention impact. Chi square analysis will be used to test the difference in the proportion of high-likelihood risk Lynch syndrome patients being referred for genetic testing before and after intervention implementation. A paired t-test will be used to assess the mean time from the pathology test results to referral for high

  1. A short course in quantum information theory. An approach from theoretical physics

    Energy Technology Data Exchange (ETDEWEB)

    Diosi, L. [KFKI Research Institute for Partical and Nuclear Physics, Budapest (Hungary)

    2007-07-01

    This short and concise primer takes the vantage point of theoretical physics and the unity of physics. It sets out to strip the burgeoning field of quantum information science to its basics by linking it to universal concepts in physics. An extensive lecture rather than a comprehensive textbook, this volume is based on courses delivered over several years to advanced undergraduate and beginning graduate students, but essentially it addresses anyone with a working knowledge of basic quantum physics. Readers will find these lectures a most adequate entry point for theoretical studies in this field. (orig.)

  2. Theoretical analysis of two ACO approaches for the traveling salesman problem

    DEFF Research Database (Denmark)

    Kötzing, Timo; Neumann, Frank; Röglin, Heiko

    2012-01-01

    Bioinspired algorithms, such as evolutionary algorithms and ant colony optimization, are widely used for different combinatorial optimization problems. These algorithms rely heavily on the use of randomness and are hard to understand from a theoretical point of view. This paper contributes...... to the theoretical analysis of ant colony optimization and studies this type of algorithm on one of the most prominent combinatorial optimization problems, namely the traveling salesperson problem (TSP). We present a new construction graph and show that it has a stronger local property than one commonly used...

  3. A systematic review of current and emergent manipulator control approaches

    Science.gov (United States)

    Ajwad, Syed Ali; Iqbal, Jamshed; Ullah, Muhammad Imran; Mehmood, Adeel

    2015-06-01

    Pressing demands of productivity and accuracy in today's robotic applications have highlighted an urge to replace classical control strategies with their modern control counterparts. This recent trend is further justified by the fact that the robotic manipulators have complex nonlinear dynamic structure with uncertain parameters. Highlighting the authors' research achievements in the domain of manipulator design and control, this paper presents a systematic and comprehensive review of the state-of-the-art control techniques that find enormous potential in controlling manipulators to execute cuttingedge applications. In particular, three kinds of strategies, i.e., intelligent proportional-integral-derivative (PID) scheme, robust control and adaptation based approaches, are reviewed. Future trend in the subject area is commented. Open-source simulators to facilitate controller design are also tabulated. With a comprehensive list of references, it is anticipated that the review will act as a firsthand reference for researchers, engineers and industrialinterns to realize the control laws for multi-degree of freedom (DOF) manipulators.

  4. RECURRENT ORAL CANCER: CURRENT AND EMERGING THERAPEUTIC APPROACHES

    Directory of Open Access Journals (Sweden)

    Sabrina Daniela Silva

    2012-07-01

    Full Text Available Oral cancer cavity (OCC is associated with high incidence of loco-regional recurrences, which account for the majority of treatment failures post-surgery and radiotherapy. The time-course of relapse manifestation and metastasis are unpredictable. Relapsed OCC represents a major clinical challenge in part due to their aggressive and invasive behaviors. Chemotherapy remains the only option for advanced OCC whenever salvage surgery or re-irradiation is not feasible, but its efficacy is limited as a result of the drug resistance development. Alternatives to use of different permutations of standard cytotoxic drugs or combinations with modulators of drug resistance have led to incremental therapeutic benefits. The introduction of targeted agents and biologics against selective targets that drive cancer progression has opened-up optimism to achieve superior therapeutic activity and overcome drug resistance because, unlike the non-selective cytotoxic, the target can be monitored at molecular levels to identify patients who can benefit from the drug. This review discusses the multifactorial aspects of clinical drug resistance and emerging therapeutic approaches in recurrent OCC, emphasizing recent advances in targeted therapies, immunotherapy, and potential relevance of new concepts such as epithelial-mesenchymal transition and cancer stem cell hypothesis to drug resistance.

  5. Current Approaches Toward Quantitative Mapping of the Interactome.

    Science.gov (United States)

    Buntru, Alexander; Trepte, Philipp; Klockmeier, Konrad; Schnoegl, Sigrid; Wanker, Erich E

    2016-01-01

    Protein-protein interactions (PPIs) play a key role in many, if not all, cellular processes. Disease is often caused by perturbation of PPIs, as recently indicated by studies of missense mutations. To understand the associations of proteins and to unravel the global picture of PPIs in the cell, different experimental detection techniques for PPIs have been established. Genetic and biochemical methods such as the yeast two-hybrid system or affinity purification-based approaches are well suited to high-throughput, proteome-wide screening and are mainly used to obtain qualitative results. However, they have been criticized for not reflecting the cellular situation or the dynamic nature of PPIs. In this review, we provide an overview of various genetic methods that go beyond qualitative detection and allow quantitative measuring of PPIs in mammalian cells, such as dual luminescence-based co-immunoprecipitation, Förster resonance energy transfer or luminescence-based mammalian interactome mapping with bait control. We discuss the strengths and weaknesses of different techniques and their potential applications in biomedical research.

  6. Current approaches to fine mapping of antigen-antibody interactions.

    Science.gov (United States)

    Abbott, W Mark; Damschroder, Melissa M; Lowe, David C

    2014-08-01

    A number of different methods are commonly used to map the fine details of the interaction between an antigen and an antibody. Undoubtedly the method that is now most commonly used to give details at the level of individual amino acids and atoms is X-ray crystallography. The feasibility of undertaking crystallographic studies has increased over recent years through the introduction of automation, miniaturization and high throughput processes. However, this still requires a high level of sophistication and expense and cannot be used when the antigen is not amenable to crystallization. Nuclear magnetic resonance spectroscopy offers a similar level of detail to crystallography but the technical hurdles are even higher such that it is rarely used in this context. Mutagenesis of either antigen or antibody offers the potential to give information at the amino acid level but suffers from the uncertainty of not knowing whether an effect is direct or indirect due to an effect on the folding of a protein. Other methods such as hydrogen deuterium exchange coupled to mass spectrometry and the use of short peptides coupled with ELISA-based approaches tend to give mapping information over a peptide region rather than at the level of individual amino acids. It is quite common to use more than one method because of the limitations and even with a crystal structure it can be useful to use mutagenesis to tease apart the contribution of individual amino acids to binding affinity.

  7. Cytotherapies in multiple myeloma: a complementary approach to current treatments?

    Science.gov (United States)

    Ciavarella, Sabino; Caselli, Anna; Savonarola, Annalisa; Tamma, Antonella Valentina; Tucci, Marco; Silvestris, Franco

    2013-06-01

    Based on their tumor tropism, mesenchymal stem cells (MSCs) have been proposed as carriers of cytotoxic molecules in pioneering strategies of anti-cancer gene therapy. Similar to solid tumors, MSCs, genetically modified to stably express the TNF-related apoptosis-inducing ligand (TRAIL), have been applied to counter-attack multiple myeloma (MM) in vitro and envisioned as a promising strategy for future anti-MM treatments. Accumulating evidence based on the detection of genetic and functional abnormalities in MSCs from MM patients points to the supportive function of MSCs in both the development and progression of MM, driven by chronic interplays with malignant cells within the marrow milieu. In this review, we revisit the function of MSCs in the pathophysiology of MM and explore the pivotal mechanisms of their interaction with myeloma cells. We also discuss the therapeutic significance of novel strategies using TRAIL-engineered MSCs in this cancer model, dissecting their role as new tools for future treatments against MM. A cytotherapy based on TRAIL-engineered MSCs against MM may be successfully combined with either conventional approaches of autologous stem cell transplantation or with novel anti-MM drugs. Intensive preclinical investigations are required to identify the best sources as well as modalities of MSC administration, thus defining the translational suitability of this strategy in the clinical setting.

  8. Current approaches towards quantitative mapping of the interactome

    Directory of Open Access Journals (Sweden)

    Alexander eBuntru

    2016-05-01

    Full Text Available Protein-protein interactions (PPIs play a key role in many, if not all, cellular processes. Disease is often caused by perturbation of PPIs, as recently indicated by studies of missense mutations. To understand the associations of proteins and to unravel the global picture of PPIs in the cell, different experimental detection techniques for PPIs have been established. Genetic and biochemical methods such as the yeast two-hybrid (Y2H system or affinity purification-based approaches are well suited to high-throughput, proteome-wide screening and are mainly used to obtain qualitative results. However, they have been criticized for not reflecting the cellular situation or the dynamic nature of PPIs. In this review, we provide an overview of various genetic methods that go beyond qualitative detection and allow quantitative measuring of PPIs in mammalian cells, such as DULIP, FRET or LUMIER with BACON. We discuss the strengths and weaknesses of different techniques and their potential applications in biomedical research.

  9. Treatment of preeclampsia: current approach and future perspectives.

    Science.gov (United States)

    Berzan, Ecaterina; Doyle, Ross; Brown, Catherine M

    2014-09-01

    Hypertension is the most common medical disorder encountered during pregnancy, occurring in about 6-8 % of pregnancies. Preeclampsia is a pregnancy-specific disorder that occurs after 20 weeks' gestation, characterized by hypertension and proteinuria. Preeclampsia can also occur superimposed upon chronic hypertension. Eclampsia is the convulsive form of preeclampsia, and affects 0.1 % of all pregnancies. In low-income and middle-income countries, preeclampsia and eclampsia are associated with 10-15 % of direct maternal deaths. Women who develop preeclampsia in pregnancy are at greater risk of cardiovascular and cerebrovascular events even years after their pregnancies. There is significant progress in the elucidation of the underlying mechanisms and pathophysiology of preeclampsia, although its therapeutics remains challenging; delivery of the fetus is still the definitive treatment. Different international societies have produced recommendations and guidelines for clinicians treating preeclampsia, with an overall goal of improving maternal and fetal outcomes. In this review, we focus on the level of blood pressure at which to commence treatment and the current clinical management strategies available to treat and possibly prevent preeclampsia. We also briefly outline some newer perspectives on management of the disorder.

  10. Ocular Behçet disease: current therapeutic approaches.

    Science.gov (United States)

    Evereklioglu, Cem

    2011-11-01

    To alert physician to timely recognition and current treatment of recurrent hypopyon iridocyclitis or panuveitis in ocular Behçet disease (OBD). Interferon-α, rituximab, intravitreal triamcinolone, and biological response modifiers by tumor necrosis factor inhibitors such as infliximab and adalimumab are being used increasingly for the treatment of severe sight-threatening ocular inflammation including retinal vasculitis and cystoid macular edema (CME). Biological agents offer tremendous potential in the treatment of OBD. Given that OBD predominantly afflicts the younger adults in their most productive years, dermatologist, rheumatologist, internist, or general practitioners supervising patients with oculo-articulo-oromucocutaneous syndromes should be aware of systemic Behçet disease. Early recognition of ocular involvement is important and such patients should strongly be instructed to visit immediately an ophthalmologist, as uveitis management differs from extraocular involvements with high ocular morbidity from sight-threatening complications due to relapsing inflammatory attacks in the posterior segment of the eye. A single infliximab infusion should be considered for the control of acute panuveitis, whereas repeated long-term infliximab infusions were proved to be more effective in reducing the number of episodes in refractory uveoretinitis with faster regression and complete remission of CME.

  11. Amyotrophic lateral sclerosis: clinical features and current treatment approaches

    Directory of Open Access Journals (Sweden)

    Tuba Tulay Koca

    2015-06-01

    Full Text Available Amyotrophic lateral sclerosis also known as Lou Gehring's disease, is the most common motor neuron disease characterized by motor neuron degeneration in the primary cortex, brainstem and spinal cord. This leads to widespread paralysis, respiratory insufficiency and death within an average of 3-5 years from disease onset. Majority of cases is sporadic and only 10% have a family story. One of the most interesting discovery in the field of neurodegeneration in recent years is genetic mutation in the C9orf72 (chromosome 9 open reading frame 72 gene, the most common mutation found to be causative of frontotemporal dementia, amyotrophic lateral sclerosis and concomitant of these two diseases. Currently curative therapy for amyotrophic lateral sclerosis is lacking. To date, one medication, Riluzole, has been proved to prolong survival, approximately 3-5 months, in amyotrophic lateral sclerosis. Researches aim to slow disease progression by targeting known pathophysiological pathways or genetics defects. Only symptomatic care to improve quality of life and survival is suggested. These includes respiratory and nutrition support; dysphagia and gastrostomy management; communication and mobility programs; spasticity prevention; pain medication; management of cognitive dysfunction, depression, mood dysorders (especially apathy, fatigue, sleep disturbance and prevention of deep venous thrombosis. [Archives Medical Review Journal 2015; 24(2.000: 182-194

  12. The aetiology ofautism spectrum disorders. An overview of current approaches

    Directory of Open Access Journals (Sweden)

    Paulina Gołaska

    2013-03-01

    Full Text Available Despite the great popularity of autism among researchers, its main cause still remains unknown. However, there are many theories which describe the mechanisms of this disorder. On the other hand, one who tries to integrate them seems to be helpless according to their contradictory and – in most cases – hypothetical status. In a context of this inac‑ curacy, focusing only on one of the concepts would be probably very disadvantageous. As many researchers suggest, the etiology of autism is complex and it is the interaction of multiple factors which implies the disorder appears. It seems that the nature of autism is equifinal and heterogeneous. Thus, the aim of this article is to present a review of current biological theories of autism etiology and to indicate the environmental as well as innate risk factors which may disturb the natural pathway of child development: prenatal (which increase the probability of autism emergence as early as in the first or second year of life or perinatal ones (low birth weight, hypoxia, age of the mother, her educational sta‑ tus. The foetal testosterone theory of autism and its general consequences for the child development will be described also. Finally, the neurological, neurochemical and neuroanatomical dysfunctions in autism will be presented.

  13. Current approaches toward production of secondary plant metabolites

    Directory of Open Access Journals (Sweden)

    Md. Sarfaraj Hussain

    2012-01-01

    Full Text Available Plants are the tremendous source for the discovery of new products with medicinal importance in drug development. Today several distinct chemicals derived from plants are important drugs, which are currently used in one or more countries in the world. Secondary metabolites are economically important as drugs, flavor and fragrances, dye and pigments, pesticides, and food additives. Many of the drugs sold today are simple synthetic modifications or copies of the naturally obtained substances. The evolving commercial importance of secondary metabolites has in recent years resulted in a great interest in secondary metabolism, particularly in the possibility of altering the production of bioactive plant metabolites by means of tissue culture technology. Plant cell and tissue culture technologies can be established routinely under sterile conditions from explants, such as plant leaves, stems, roots, and meristems for both the ways for multiplication and extraction of secondary metabolites. In vitro production of secondary metabolite in plant cell suspension cultures has been reported from various medicinal plants, and bioreactors are the key step for their commercial production. Based on this lime light, the present review is aimed to cover phytotherapeutic application and recent advancement for the production of some important plant pharmaceuticals.

  14. SAPHO Syndrome: Current Developments and Approaches to Clinical Treatment.

    Science.gov (United States)

    Firinu, Davide; Garcia-Larsen, Vanessa; Manconi, Paolo Emilio; Del Giacco, Stefano R

    2016-06-01

    SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis, and osteitis) is a rare autoimmune disease which, due to its clinical presentation and symptoms, is often misdiagnosed and unrecognized. Its main features are prominent inflammatory cutaneous and articular manifestations. Treatments with immunosuppressive drugs have been used for the management of SAPHO with variable results. To date, the use of anti-TNF-α agents has proved to be an effective alternative to conventional treatment for unresponsive or refractory SAPHO cases. TNF-α is a pro-inflammatory cytokine and pivotal regulator of other cytokines, including IL-1 β, IL-6, and IL-8, involved in inflammation, acute-phase response induction, and chemotaxis. IL-1 inhibition strategies with anakinra have shown efficacy as first and second lines of treatment. In this review, we will describe the main characteristics of biological drugs currently used for SAPHO syndrome. We also describe some of the promising therapeutic effects of ustekinumab, an antibody against the p40 subunit of IL-12 and IL-23, after failure of multiple drugs including anti-TNF-α and anakinra. We discuss the use and impact of the new anti-IL-1 antagonists involved in the IL-17 blockade, in particular for the most difficult-to-treat SAPHO cases.

  15. Theoretical study of molecular vibrations in electron momentum spectroscopy experiments on furan: An analytical versus a molecular dynamical approach

    Energy Technology Data Exchange (ETDEWEB)

    Morini, Filippo; Deleuze, Michael S., E-mail: michael.deleuze@uhasselt.be [Center of Molecular and Materials Modelling, Hasselt University, Agoralaan Gebouw D, B-3590 Diepenbeek (Belgium); Watanabe, Noboru; Takahashi, Masahiko [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan)

    2015-03-07

    The influence of thermally induced nuclear dynamics (molecular vibrations) in the initial electronic ground state on the valence orbital momentum profiles of furan has been theoretically investigated using two different approaches. The first of these approaches employs the principles of Born-Oppenheimer molecular dynamics, whereas the so-called harmonic analytical quantum mechanical approach resorts to an analytical decomposition of contributions arising from quantized harmonic vibrational eigenstates. In spite of their intrinsic differences, the two approaches enable consistent insights into the electron momentum distributions inferred from new measurements employing electron momentum spectroscopy and an electron impact energy of 1.2 keV. Both approaches point out in particular an appreciable influence of a few specific molecular vibrations of A{sub 1} symmetry on the 9a{sub 1} momentum profile, which can be unravelled from considerations on the symmetry characteristics of orbitals and their energy spacing.

  16. Treatment of cutaneous melanoma: current approaches and future prospects

    Directory of Open Access Journals (Sweden)

    Alain P Algazi

    2010-08-01

    Full Text Available Alain P Algazi1, Christopher W Soon2, Adil I Daud11Department of Medicine, Division of Hematology and Oncology, 2Department of Dermatology, University of California, San Francisco San Francisco, CA, USAAbstract: Melanoma is the most aggressive and deadly type of skin cancer. Surgical resection with or without lymph node sampling is the standard of care for primary cutaneous melanoma. Adjuvant therapy decisions may be informed by careful consideration of prognostic factors. High-dose adjuvant interferon alpha-2b increases disease-free survival and may modestly improve overall survival. Less toxic alternatives for adjuvant therapy are currently under study. External beam radiation therapy is an option for nodal beds where the risk of local recurrence is very high. In-transit melanoma metastases may be treated locally with surgery, immunotherapy, radiation, or heated limb perfusion. For metastatic melanoma, the options include chemotherapy or immunotherapy; targeted anti-BRAF and anti-KIT therapy is under active investigation. Standard chemotherapy yields objective tumor responses in approximately 10%–20% of patients, and sustained remissions are uncommon. Immunotherapy with high-dose interleukin-2 yields objective tumor responses in a minority of patients; however, some of these responses may be durable. Identification of activating mutations of BRAF, NRAS, c-KIT, and GNAQ in distinct clinical subtypes of melanoma suggest that these are molecularly distinct. Emerging data from clinical trials suggest that substantial improvements in the standard of care for melanoma may be possible.Keywords: melanoma, resection, immune modulation, small molecule kinase inhibitors, chemotherapy, clinical trials

  17. [Current approaches to explain the virulence of Acinetobacter baumannii].

    Science.gov (United States)

    Aşık, Gülşah

    2011-04-01

    Acinetobacter baumannii which is one of the most frequent nosocomial pathogens, has drawn attention in the last years owing to multi-drug resistant strains. A.baumannii may give rise to nosocomial epidemics especially in intensive care units and may lead to treatment failure due to its increasing antimicrobial resistance. These gram-negative non-fermentative coccobacilli may be encountered also in community associated infections. However, they are frequently isolated in pneumonia, urinary tract infection, bacteremia, meningitis and wound infections that develop in patients hospitalized for serious diseases. Although detailed data about the epidemiology and antimicrobial resistance patterns related to this bacteria exist, relatively limited data is present about the virulence factors and environmental physiology of A.baumannii. The role of some bacterial virulence factors in the pathogenesis of Acinetobacter infections have been enlightened by recent investigations. Among these virulence factors, production of extracellular enzymes with lipolytic and cytolytic activities, outer membrane protein (AbOmpA) with apoptotic effects on epithelial cells, adhesion molecules (fimbria and AbOmpA) that function during attachment to epithelial cells, K1 type capsular structure, type-1 pili and AbOmpA induced biofilm formation, siderophore (acinetobactin) or hemin mediated iron acquisition mechanisms, quorum sensing system that functions by the help of N-acyl homoserine lacton signal molecules and cellular components that enable Acinetobacter species to live under inappropriate environmental conditions like dryness, low temperature, restricted nutritional elements, can be counted. New information about the virulence factors will help better understanding of the adaptive response of A.baumannii in the host setting. This review is focused on the current information about the virulence factors of of A.baumannii.

  18. Game-Theoretic Approach for Solving Multiobjective Flow Problems on Networks

    Directory of Open Access Journals (Sweden)

    Maria A. Fonoberova

    2005-10-01

    Full Text Available The game-theoretic formulation of the multiobjective multicommodity flow problem is considered. The dynamic version of this problem is studied and an algorithm for its solving, based on the concept of multiobjective games, is proposed. Mathematics Subject Classification 2000: 90B10, 90C35, 90C27, 90C47.

  19. Between altruism and narcissism: An action theoretical approach of personal homepages devoted to existential meaning

    NARCIS (Netherlands)

    Hijmans, E.J.S.; Selm, M. van

    2002-01-01

    This article aims to examine existential meaning constructions from an action theoretical perspective in a specific Internet environment: the personal homepage. Personal homepages are on-line multi-media documents addressing the question ‘Who am I?’ Authors of personal homepages provide information

  20. Between altruism and narcissism: An action theoretical approach of personal homepages devoted to existential meaning

    NARCIS (Netherlands)

    Hijmans, E.J.S.; Selm, M. van

    2002-01-01

    This article aims to examine existential meaning constructions from an action theoretical perspective in a specific Internet environment: the personal homepage. Personal homepages are on-line multi-media documents addressing the question ‘Who am I?’ Authors of personal homepages provide information

  1. A system-theoretical approach to selective grid coarsening of reservoir models

    NARCIS (Netherlands)

    Vakili-Ghahani, S.A.; Jansen, J.D.

    2011-01-01

    From a system-theoretical point of view and for a given configuration of wells, there are only a limited number of degrees of freedom in the input–output dynamics of a reservoir system. This means that a large number of combinations of the state variables (pressure and saturation values) are not act

  2. Yes-no question/marking in Italian dialects : a typological, theoretical and experimental approach.

    NARCIS (Netherlands)

    Lusini, Sara

    This dissertation provides an account of polar questions in Italian dialects from a typological, theoretical and empirical perspective. Both data from the existing literature and new data from the author’s fieldwork are included in this study. It is shown that Italian dialects display a relatively

  3. Distinguishing spectral and temporal properties of speech using an information-theoretic approach

    DEFF Research Database (Denmark)

    Christiansen, Thomas Ulrich; Greenberg, Steven

    2007-01-01

    The spectro-temporal coding of Danish consonants was investigated using an information-theoretic analysis. Listeners identified eleven consonants spoken in CV[l] context. In each condition, only a portion of the original spectrum was played. Center frequencies of 750, 1500 and 3000 Hz, were prese...

  4. Theoretical approach and impact of correlations on the critical packet generation rate in traffic dynamics on complex networks

    CERN Document Server

    Fronczak, Piotr

    2015-01-01

    Using the formalism of the biased random walk in random uncorrelated networks with arbitrary degree distributions, we develop theoretical approach to the critical packet generation rate in traffic based on routing strategy with local information. We explain microscopic origins of the transition from the flow to the jammed phase and discuss how the node neighbourhood topology affects the transport capacity in uncorrelated and correlated networks.

  5. Theoretical base of the approach to the representation of aggregate information on the cross sections of the scattering processes

    Directory of Open Access Journals (Sweden)

    Alla A. Mityureva

    2015-12-01

    Full Text Available In the present paper, the approach to the representation of aggregate information on the cross sections of elementary processes is described and its justification within mathematical statistics is given. It is caused by necessity of integrated account of the results obtained by different works at different times, in different groups, based on experimental and theoretical studies in various energy ranges. The main attention is paid to the process of electron-atom scattering. As an example of the proposed approach application, the aggregate result on thus obtained integral cross sections of electron impact excitation of the transitions in the hydrogen atom is presented.

  6. A Bayesian Game-Theoretic Approach for Distributed Resource Allocation in Fading Multiple Access Channels

    Directory of Open Access Journals (Sweden)

    Gaoning He

    2010-01-01

    Full Text Available A Bayesian game-theoretic model is developed to design and analyze the resource allocation problem in K-user fading multiple access channels (MACs, where the users are assumed to selfishly maximize their average achievable rates with incomplete information about the fading channel gains. In such a game-theoretic study, the central question is whether a Bayesian equilibrium exists, and if so, whether the network operates efficiently at the equilibrium point. We prove that there exists exactly one Bayesian equilibrium in our game. Furthermore, we study the network sum-rate maximization problem by assuming that the users coordinate according to a symmetric strategy profile. This result also serves as an upper bound for the Bayesian equilibrium. Finally, simulation results are provided to show the network efficiency at the unique Bayesian equilibrium and to compare it with other strategies.

  7. Exploring SiSn as a performance enhancing semiconductor: A theoretical and experimental approach

    KAUST Repository

    Hussain, Aftab M.

    2014-12-14

    We present a novel semiconducting alloy, silicon-tin (SiSn), as channel material for complementary metal oxide semiconductor (CMOS) circuit applications. The material has been studied theoretically using first principles analysis as well as experimentally by fabricating MOSFETs. Our study suggests that the alloy offers interesting possibilities in the realm of silicon band gap tuning. We have explored diffusion of tin (Sn) into the industry\\'s most widely used substrate, silicon (100), as it is the most cost effective, scalable and CMOS compatible way of obtaining SiSn. Our theoretical model predicts a higher mobility for p-channel SiSn MOSFETs, due to a lower effective mass of the holes, which has been experimentally validated using the fabricated MOSFETs. We report an increase of 13.6% in the average field effect hole mobility for SiSn devices compared to silicon control devices.

  8. ON THE APPLICATION OF PARTIAL BARRIERS FOR SPINNING MACHINE NOISE CONTROL: A THEORETICAL AND EXPERIMENTAL APPROACH

    Directory of Open Access Journals (Sweden)

    M. R. Monazzam, A. Nezafat

    2007-04-01

    Full Text Available Noise is one of the most serious challenges in modern community. In some specific industries, according to the nature of process, this challenge is more threatening. This paper describes a means of noise control for spinning machine based on experimental measurements. Also advantages and disadvantages of the control procedure are added. Different factors which may affect the performance of the barrier in this situation are also mentioned. To provide a good estimation of the control measure, a theoretical formula is also described and it is compared with the field data. Good agreement between the results of filed measurements and theoretical presented model was achieved. No obvious noise reduction was seen by partial indoor barriers in low absorbent enclosed spaces, since the reflection from multiple hard surfaces is the main dominated factor in the tested environment. At the end, the situation of the environment and standards, which are necessary in attaining the ideal results, are explained.

  9. A novel game theoretic approach for modeling competitive information diffusion in social networks with heterogeneous nodes

    Science.gov (United States)

    Agha Mohammad Ali Kermani, Mehrdad; Fatemi Ardestani, Seyed Farshad; Aliahmadi, Alireza; Barzinpour, Farnaz

    2017-01-01

    Influence maximization deals with identification of the most influential nodes in a social network given an influence model. In this paper, a game theoretic framework is developed that models a competitive influence maximization problem. A novel competitive influence model is additionally proposed that incorporates user heterogeneity, message content, and network structure. The proposed game-theoretic model is solved using Nash Equilibrium in a real-world dataset. It is shown that none of the well-known strategies are stable and at least one player has the incentive to deviate from the proposed strategy. Moreover, violation of Nash equilibrium strategy by each player leads to their reduced payoff. Contrary to previous works, our results demonstrate that graph topology, as well as the nodes' sociability and initial tendency measures have an effect on the determination of the influential node in the network.

  10. Control-theoretic Approach to Communication with Feedback: Fundamental Limits and Code Design

    CERN Document Server

    Ardestanizadeh, Ehsan

    2010-01-01

    Feedback communication is studied from a control-theoretic perspective, mapping the communication problem to a control problem in which the control signal is received through the same noisy channel as in the communication problem, and the (nonlinear and time-varying) dynamics of the system determine a subclass of encoders available at the transmitter. The MMSE capacity is defined to be the supremum exponential decay rate of the mean square decoding error. This is upper bounded by the information-theoretic feedback capacity, which is the supremum of the achievable rates. A sufficient condition is provided under which the upper bound holds with equality. For the special class of stationary Gaussian channels, a simple application of Bode's integral formula shows that the feedback capacity, recently characterized by Kim, is equal to the maximum instability that can be tolerated by the controller under a given power constraint. Finally, the control mapping is generalized to the N-sender AWGN multiple access channe...

  11. A field theoretic approach to the energy momentum tensor for theories coupled with gravity

    OpenAIRE

    Mukherjee, Pradip; Saha, Anirban; Roy, Amit Singha

    2016-01-01

    We provide a field-theoretic algorithm of obtaining energy momentum tensor (EMT) for gravitationally coupled theories. The method is based on an auxiliary field theory and equally applicable to both minimal and non-minimal coupling. The algorithm illuminates the connection between the EMT, obtained by functional variation of the metric, and local balance of energy and momentum. Our method is of cardinal value for the proper identification of the EMT in context of non-minimally coupled gravity...

  12. Security-aware Virtual Machine Allocation in the Cloud: A Game Theoretic Approach

    Science.gov (United States)

    2015-01-13

    has significantly more to lose. The paper in [1] presented the externality problem within the context of game theory, and this paper aimed to solve ...later in the paper. Section IV will now explain and setup the problem in the context of game theory. IV. GAME MODEL This section considers four...In Section VI we extend the problem to n players and m hypervisors. Along with the commonly applied game theoretic assumptions of rationality and

  13. An extended berry's field theoretic approach to intra-urban system in the toyota planning region

    OpenAIRE

    Yano, Keiji

    1987-01-01

    An interdependence between spatial structure and spatial behavior in the Toyota Planning Region is examined, based on the framework of the Berry(1966)'s general field theory of spatial behavior. Canonical analysis reveals journey to work is determined by areal difference of industrial activities, and journey to shop is by areal differences of commercial activities and urban land use. While conventional field theoretic studies in geography have laid emphasis on mere description of the interdep...

  14. The yoga of schemic Grothendieck rings, a topos-theoretical approach

    CERN Document Server

    Schoutens, Hans

    2010-01-01

    We propose a suitable substitute for the classical Grothendieck ring of an algebraically closed field, in which any quasi-projective scheme is represented, while maintaining its non-reduced structure. This yields a more subtle invariant, called the schemic Grothendieck ring, in which we can formulate a form of integration resembling Kontsevich's motivic integration via arc schemes. Whereas the original construction was via definability, we have translated in this paper everything into a topos-theoretic framework.

  15. Design Activities in the NorwegianSeafood Industry: A theoretical approach to understanding cooperation and communication

    OpenAIRE

    Schulte, Kjersti Øverbø

    2009-01-01

    The thesis discusses design activities in the Norwegian seafood processing industry, with focus on cooperation between packaging suppliers and designers. There is a twofold objective: to increase understanding of how industrial design methodology can be utilised in the seafood industry, and to introduce a theoretical foundation for cooperation and communication in industrial design methodology.Sales of fish and seafood represent Norway’s third largest export. Seafood is an industrially proces...

  16. Defining and measuring blood donor altruism: a theoretical approach from biology, economics and psychology.

    Science.gov (United States)

    Evans, R; Ferguson, E

    2014-02-01

    While blood donation is traditionally described as a behaviour motivated by pure altruism, the assessment of altruism in the blood donation literature has not been theoretically informed. Drawing on theories of altruism from psychology, economics and evolutionary biology, it is argued that a theoretically derived psychometric assessment of altruism is needed. Such a measure is developed in this study that can be used to help inform both our understanding of the altruistic motives of blood donors and recruitment intervention strategies. A cross-sectional survey (N = 414), with a 1-month behavioural follow-up (time 2, N = 77), was designed to assess theoretically derived constructs from psychological, economic and evolutionary biological theories of altruism. Theory of planned behaviour (TPB) variables and co-operation were also assessed at time 1 and a measure of behavioural co-operation at time 2. Five theoretical dimensions (impure altruism, kinship, self-regarding motives, reluctant altruism and egalitarian warm glow) of altruism were identified through factor analyses. These five altruistic motives differentiated blood donors from non-donors (donors scored higher on impure altruism and reluctant altruism), showed incremental validity over TPB constructs to predict donor intention and predicted future co-operative behaviour. These findings show that altruism in the context of blood donation is multifaceted and complex and, does not reflect pure altruism. This has implication for recruitment campaigns that focus solely on pure altruism. © 2013 The Authors. Vox Sanguinis published by John Wiley & Sons Ltd. on behalf of International Society of Blood Transfusion.

  17. A Novel Information-Theoretic Approach for Variable Clustering and Predictive Modeling Using Dirichlet Process Mixtures

    OpenAIRE

    Yun Chen; Hui Yang

    2016-01-01

    In the era of big data, there are increasing interests on clustering variables for the minimization of data redundancy and the maximization of variable relevancy. Existing clustering methods, however, depend on nontrivial assumptions about the data structure. Note that nonlinear interdependence among variables poses significant challenges on the traditional framework of predictive modeling. In the present work, we reformulate the problem of variable clustering from an information theoretic pe...

  18. δ-Cut Decision-Theoretic Rough Set Approach: Model and Attribute Reductions

    Directory of Open Access Journals (Sweden)

    Hengrong Ju

    2014-01-01

    Full Text Available Decision-theoretic rough set is a quite useful rough set by introducing the decision cost into probabilistic approximations of the target. However, Yao’s decision-theoretic rough set is based on the classical indiscernibility relation; such a relation may be too strict in many applications. To solve this problem, a δ-cut decision-theoretic rough set is proposed, which is based on the δ-cut quantitative indiscernibility relation. Furthermore, with respect to criterions of decision-monotonicity and cost decreasing, two different algorithms are designed to compute reducts, respectively. The comparisons between these two algorithms show us the following: (1 with respect to the original data set, the reducts based on decision-monotonicity criterion can generate more rules supported by the lower approximation region and less rules supported by the boundary region, and it follows that the uncertainty which comes from boundary region can be decreased; (2 with respect to the reducts based on decision-monotonicity criterion, the reducts based on cost minimum criterion can obtain the lowest decision costs and the largest approximation qualities. This study suggests potential application areas and new research trends concerning rough set theory.

  19. Conceptual and empirical problems with game theoretic approaches to language evolution

    Directory of Open Access Journals (Sweden)

    Jeffrey eWatumull

    2014-03-01

    Full Text Available The importance of game theoretic models to evolutionary theory has been in formulating elegant equations that specify the strategies to be played and the conditions to be satisfied for particular traits to evolve. These models, in conjunction with experimental tests of their predictions, have successfully described and explained the costs and benefits of varying strategies and the dynamics for establishing equilibria in a number of evolutionary scenarios, including especially cooperation, mating, and aggression. Over the past decade or so, game theory has been applied to model the evolution of language. In contrast to the aforementioned scenarios, however, we argue that these models are problematic due to conceptual confusions and empirical difficiences. In particualr, these models conflate the comptutations and representations of our language faculty (mechanism with its utility in communication (function; model languages as having different fitness functions for which there is no evidence; depend on assumptions for the starting state of the system, thereby begging the question of how these systems evolved; and to date, have generated no empirical studies at all. Game theoretic models of language evolution have therefore failed to advance how or why language evolved, or why it has the particular representations and computations that it does. We conclude with some brief suggestions for how this situation might be ameliorated, enabling this important theoretical tool to make substantive empirical contributions.

  20. Neutrosophic Game Theoretic Approach to Indo-Pak Conflict over Jammu-Kashmir

    Directory of Open Access Journals (Sweden)

    Surapati Pramanik

    2014-03-01

    Full Text Available The study deals with the enduring conflict between India and Pakistan over Jammu and Kashmir since 1947. The ongoing conflict is analyzed as an enduring rivalry; characterized by three major wars (1947-48, 1965, 1971, low intensity military conflict (Siachen, mini war at Kargil (1999, internal insurgency, cross border terrorism. We examine the progress and the status of the dispute, as well as the dynamics of the India Pakistan relationship by considering the influence of USA and China in crisis dynamics. We discuss the possible solutions offered by the various study groups and persons. Most of the studies were done in crisp environment. Pramanik and Roy (S. Pramanik and T.K. Roy, Game theoretic model to the Jammu-Kashmir conflict between India and Pakistan. International Journal of Mathematical Archive (IJMA, 4(8 (2013, 162-170. studied game theoretic model toJammu and Kashmir conflict in crisp environment. In the present study we have extended the concept of the game theoric model of the Jammu and Kashmir conflict in neutrosophic envirorment. We have explored the possibilities and developed arguments for an application of principle of neutrosophic game theory to understand properly of the Jammu and Kashmir conflict in terms of goals and strategy of either side. Standard 2×2 zero-sum game theoretic model used to identify an optimal solution.

  1. Assessing the Distribution and State of Subsurface Water on Mars: Theoretical Expectations, the Geologic Evidence, and Potential Geophysical Approaches

    Science.gov (United States)

    Clifford, S. M.

    2005-12-01

    The abundance and distribution of water on Mars has important implications for understanding the planet's geologic, hydrologic, and climatic history; the potential origin and continued survival of life; and the accessibility of a critical in-situ resource for sustaining future human explorers. For this reason, the search for water has become a key objective of NASA's Mars Exploration Program. Evidence of water, both past and present, is found almost everywhere, but most persuasively in the form of the planet's outflow channels -- broad scoured depressions hundreds of kilometers long that emerge abruptly from large areas of collapsed and disrupted terrain, the apparent result of a massive release of subpermafrost groundwater. Based on a conservative estimate of the volume of water required to erode the channels, Carr (Icarus, 68, 187-216, 1986) has estimated that Mars may possess a total planetary inventory of water equivalent to a global ocean 0.5 - 1 km deep. Of this global inventory, ~0.000001% is found in the atmosphere, while ~5-10% is visible as ice in the perennial polar caps. This leaves ~90-95% of the planetary inventory of water unaccounted for, the vast bulk of which is believed to reside, as ground ice and groundwater, within the planet's crust. Theoretical and geomorphic approaches to assessing the current distribution and state of subsurface water on Mars face numerous obstacles -- thus geophysical techniques hold the most promise. The first such investigation, the Gamma-Ray Neutron Spectrometer aboard the Mars Odyssey Orbiter, arrived at Mars in 2001. It revealed that the top half-meter of the Martian regolith is rich in hydrogen at latitudes above ~40-degrees, an observation consistent with the presence of near-surface ground ice. Assessing the distribution of water at greater depths (up to several kilometers) is one of the chief objectives of the MARSIS experiment on ESA's Mars Express spacecraft. MARSIS is a low-frequency (1-5 MHz) orbital radar

  2. The Approach Towards Equilibrium in a Reversible Ising Dynamics Model: An Information-Theoretic Analysis Based on an Exact Solution

    Science.gov (United States)

    Lindgren, Kristian; Olbrich, Eckehard

    2017-08-01

    We study the approach towards equilibrium in a dynamic Ising model, the Q2R cellular automaton, with microscopic reversibility and conserved energy for an infinite one-dimensional system. Starting from a low-entropy state with positive magnetisation, we investigate how the system approaches equilibrium characteristics given by statistical mechanics. We show that the magnetisation converges to zero exponentially. The reversibility of the dynamics implies that the entropy density of the microstates is conserved in the time evolution. Still, it appears as if equilibrium, with a higher entropy density is approached. In order to understand this process, we solve the dynamics by formally proving how the information-theoretic characteristics of the microstates develop over time. With this approach we can show that an estimate of the entropy density based on finite length statistics within microstates converges to the equilibrium entropy density. The process behind this apparent entropy increase is a dissipation of correlation information over increasing distances. It is shown that the average information-theoretic correlation length increases linearly in time, being equivalent to a corresponding increase in excess entropy.

  3. Information-theoretic approach to quantum error correction and reversible measurement

    CERN Document Server

    Nielsen, M A; Schumacher, B; Barnum, H N; Caves, Carlton M.; Schumacher, Benjamin; Barnum, Howard

    1997-01-01

    Quantum operations provide a general description of the state changes allowed by quantum mechanics. The reversal of quantum operations is important for quantum error-correcting codes, teleportation, and reversing quantum measurements. We derive information-theoretic conditions and equivalent algebraic conditions that are necessary and sufficient for a general quantum operation to be reversible. We analyze the thermodynamic cost of error correction and show that error correction can be regarded as a kind of ``Maxwell demon,'' for which there is an entropy cost associated with information obtained from measurements performed during error correction. A prescription for thermodynamically efficient error correction is given.

  4. A K-theoretic approach to the classification of symmetric spaces

    CERN Document Server

    Bohle, Dennis

    2011-01-01

    We show that the classification of the symmetric spaces can be achieved by K-theoretical methods. We focus on Hermitian symmetric spaces of non-compact type, and define K-theory for JB*-triples along the lines of C*-theory. K-groups have to be provided with further invariants in order to classify. Among these are the cycles obtained from so called grids, intimately connected to the root systems of an underlying Lie-algebra and thus reminiscent of the classical classification scheme.

  5. PSYCHOLOGICAL FACTORS AFFECTING THE CONSUMER’S INTENTION TO USE E- COMMERCE: A THEORETICAL APPROACH

    OpenAIRE

    Mahmoud Al-dalahmeh; Ali Salman Saleh

    2007-01-01

    There is a need in the literature for an application of the well known social cognitive theory in the area of e-commerce. Hence, this paper develops and models a theoretical framework to study the impact of psychological factors based on the social cognitive theory on the intention to use e-commerce. More specifically, the paper examines the role of individuals’ beliefs about their abilities towards the intention to use e-commerce technology (e-commerce self-efficacy). A conceptual model, bas...

  6. Wavelength shift in a whispering gallery microdisk due to bacterial sensing: A theoretical approach

    Directory of Open Access Journals (Sweden)

    Hala Ghali

    2017-04-01

    Full Text Available Whispering gallery mode microcavities have recently been studied as a means to achieve real-time label-free detection of biological targets such as virus particles, specific DNA sequences, or proteins. Binding of a biomolecule to the surface of a microresonator will increase its path length, leading to a shift in the resonance frequency according to the reactive sensing principle. In this paper, we develop a theoretical expression that will link the reactive shift to the bacteria and microdisk parameters and help quantify the number of bacteria that bind to the surface of a 200μm-diameter silica microdisk.

  7. Direct Determination of Absolute Configuration of Methyl-Substituted Phenyloxiranes: A Combined Experimental and Theoretical Approach

    DEFF Research Database (Denmark)

    Fristrup, Peter; Lassen, Peter Rygaard; Johannessen, Christian;

    2006-01-01

    obtained from quantum mechanical calculations (density functional theory with the B3LYP hybrid exchange correlation functional with 6-31++G**, aug-cc-pVDZ, or aug-cc-pVTZ basis set) and related to the physical structure of the compounds. The absolute configuration could be established directly in each case...... by comparing experimental and theoretical spectra. In addition, we have been able to document the changes that occur both in structures and in the VA and VCD spectra due to substituent effects on the oxirane ring....

  8. A novel multi-stage direct contact membrane distillation module: Design, experimental and theoretical approaches.

    Science.gov (United States)

    Lee, Jung-Gil; Kim, Woo-Seung; Choi, June-Seok; Ghaffour, Noreddine; Kim, Young-Deuk

    2016-12-15

    An economic desalination system with a small scale and footprint for remote areas, which have a limited and inadequate water supply, insufficient water treatment and low infrastructure, is strongly demanded in the desalination markets. Here, a direct contact membrane distillation (DCMD) process has the simplest configuration and potentially the highest permeate flux among all of the possible MD processes. This process can also be easily instituted in a multi-stage manner for enhanced compactness, productivity, versatility and cost-effectiveness. In this study, an innovative, multi-stage, DCMD module under countercurrent-flow configuration is first designed and then investigate both theoretically and experimentally to identify its feasibility and operability for desalination application. Model predictions and measured data for mean permeate flux are compared and shown to be in good agreement. The effect of the number of module stages on the mean permeate flux, performance ratio and daily water production of the MDCMD system has been theoretically identified at inlet feed and permeate flow rates of 1.5 l/min and inlet feed and permeate temperatures of 70 °C and 25 °C, respectively. The daily water production of a three-stage DCMD module with a membrane area of 0.01 m(2) at each stage is found to be 21.5 kg. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Theoretical gravity darkening as a function of optical depth. A first approach to fast rotating stars

    Science.gov (United States)

    Claret, A.

    2016-04-01

    Aims: Recent observations of very fast rotating stars show systematic deviations from the von Zeipel theorem and pose a challenge to the theory of gravity-darkening exponents (β1). In this paper, we present a new insight into the problem of temperature distribution over distorted stellar surfaces to try to reduce these discrepancies. Methods: We use a variant of the numerical method based on the triangles strategy, which we previously introduced, to evaluate the gravity-darkening exponents. The novelty of the present method is that the theoretical β1 is now computed as a function of the optical depth, that is, β1 ≡ β1(τ). The stellar evolutionary models, which are necessary to obtain the physical conditions of the stellar envelopes/atmospheres inherent to the numerical method, are computed via the code GRANADA. Results: When the resulting theoretical β1(τ) are compared with the best accurate data of very fast rotators, a good agreement for the six systems is simultaneously achieved. In addition, we derive an equation that relates the locus of constant convective efficiency in the Hertzsprung-Russell (HR) diagram with gravity-darkening exponents.

  10. Growth and spectral analysis of piperazinium L-tartrate salt: A combined experimental and theoretical approach

    Science.gov (United States)

    Mathammal, R.; Sudha, N.; Shankar, R.; Rajaboopathi, M.; Janagi, S.; Prabavathi, B.

    2017-03-01

    This report discusses crystal structure, molecular arrangements, vibrational analysis, UV-Vis-NIR spectrum, fluorescence emission and second harmonic generation (SHG) efficiency of piperazinium L-tartrate (PPZ2+·Tart2-) crystals with the support of theoretical analysis. A good optical quality PPZ2+·Tart2- crystals were grown from slow evaporation of aqueous solution. The PPZ2+·Tart2- crystal belongs to monoclinic system with non-centrosymmetric space group P21. The charge transfer from donor to acceptor moieties and corresponding changes in the bond lengths and bond angles have been observed. The observed functional group vibrations in the experimental FTIR and the Raman spectrum were assigned and compared with theoretical wavenumbers of PPZ2+·Tart2-.The electron distribution on the donor and acceptor in PPZ2+·Tart2- has been clearly visualised using molecular electrostatic potential map. Compared with L-tartaric acid, red shift was observed in absorption and fluorescence spectrum. The low value of dielectric constant and dielectric loss at the higher frequency and its high second harmonic efficiency suggest PPZ2+·Tart2- crystal is less defect free and suitable for NLO applications.

  11. A novel multi-stage direct contact membrane distillation module: Design, experimental and theoretical approaches

    KAUST Repository

    Lee, Jung Gil

    2016-10-24

    An economic desalination system with a small scale and footprint for remote areas, which have a limited and inadequate water supply, insufficient water treatment and low infrastructure, is strongly demanded in the desalination markets. Here, a direct contact membrane distillation (DCMD) process has the simplest configuration and potentially the highest permeate flux among all of the possible MD processes. This process can also be easily instituted in a multi-stage manner for enhanced compactness, productivity, versatility and cost-effectiveness. In this study, an innovative, multi-stage, DCMD module under countercurrent-flow configuration is first designed and then investigate both theoretically and experimentally to identify its feasibility and operability for desalination application. Model predictions and measured data for mean permeate flux are compared and shown to be in good agreement. The effect of the number of module stages on the mean permeate flux, performance ratio and daily water production of the MDCMD system has been theoretically identified at inlet feed and permeate flow rates of 1.5 l/min and inlet feed and permeate temperatures of 70 °C and 25 °C, respectively. The daily water production of a three-stage DCMD module with a membrane area of 0.01 m2 at each stage is found to be 21.5 kg.

  12. The UBI-QEP method. A practical theoretical approach to understanding chemistry on transition metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Shustorovich, Evgeny [American Scientific Materials Technologies, Inc., New York, NY (United States); Sellers, Harrell [Department of Chemistry and Biochemistry, South Dakota State University Brooking, SD (United States)

    1998-04-01

    In this review we examine the presently available theoretical techniques for determining metal surface reaction energetics. The unity bond index-quadratic exponential potential (UBI-QEP) method, which provides heats of adsorption and reaction activation barriers with a typical accuracy of 1-3 Kcal/mol, emerges as the method with the widest applicability for complex and practically important reaction systems. We discuss in detail the theoretical foundations of the analytic UBI-QEP method which employs the most general two-body interaction potentials. The potential variable, named a bond index, is a general exponential function of the two-center bond distance. The bond indices of interacting bonds are assumed to be conserved at unity (up to the dissociation point), and we cite state-of-the-art ab initio calculations to support this assumption. The UBI-QEP method allows one to calculate the reaction energetics in a straightforward variational way. We summarize the analytic formulas for adsorbate binding energies in various coordination modes and for intrinsic and diffusion activation barriers. We also describe a computer program which makes UBI-QEP calculations fully automated. The normalized bond index-molecular dynamics (NBI-MD) simulation technique, which is an adaptation of the UBI-QEP reactive potential functions to molecular dynamics, is described. Detailed summaries of applications are given which include the Fischer-Tropsch synthesis, oxygen assisted X-H bond cleavage, hydrogen peroxide, methanol and ammonia syntheses, decomposition and reduction of NO, and SO{sub x} chemistry

  13. The UBI-QEP method: A practical theoretical approach to understanding chemistry on transition metal surfaces

    Science.gov (United States)

    Shustorovich, Evgeny; Sellers, Harrell

    In this review we examine the presently available theoretical techniques for determining metal surface reaction energetics. The unity bond index-quadratic exponential potential (UBI-QEP) method, which provides heats of adsorption and reaction activation barriers with a typical accuracy of 1-3 kcal/mol, emerges as the method with the widest applicability for complex and practically important reaction systems. We discuss in detail the theoretical foundations of the analytic UBI-QEP method which employs the most general two-body interaction potentials. The potential variable, named a bond index, is a general exponential function of the two-center bond distance. The bond indices of interacting bonds are assumed to be conserved at unity (up to the dissociation point), and we cite state-of-the-art ab initio calculations to support this assumption. The UBI-QEP method allows one to calculate the reaction energetics in a straightforward variational way. We summarize the analytic formulas for adsorbate binding energies in various coordination modes and for intrinsic and diffusion activation barriers. We also describe a computer program which makes UBI-QEP calculations fully automated. The normalized bond index-molecular dinamics, (NBI-MD) simulation technique, which is an adaptation of the UBI-QEP reactive potential functions to molecular dynamics, is described. Detailed summaries of applications are given which include the Fischer-Tropsch synthesis, oxygen assisted X-H bond cleavage, hydrogen peroxide, methanol and ammonia syntheses, decomposition and reduction of NO, and SO x chemistry.

  14. Theoretical approaches of online social network interventions and implications for behavioral change: a systematic review.

    Science.gov (United States)

    Arguel, Amaël; Perez-Concha, Oscar; Li, Simon Y W; Lau, Annie Y S

    2016-10-06

    The aim of this review was to identify general theoretical frameworks used in online social network interventions for behavioral change. To address this research question, a PRISMA-compliant systematic review was conducted. A systematic review (PROSPERO registration number CRD42014007555) was conducted using 3 electronic databases (PsycINFO, Pubmed, and Embase). Four reviewers screened 1788 abstracts. 15 studies were selected according to the eligibility criteria. Randomized controlled trials and controlled studies were assessed using Cochrane Collaboration's "risk-of-bias" tool, and narrative synthesis. Five eligible articles used the social cognitive theory as a framework to develop interventions targeting behavioral change. Other theoretical frameworks were related to the dynamics of social networks, intention models, and community engagement theories. Only one of the studies selected in the review mentioned a well-known theory from the field of health psychology. Conclusions were that guidelines are lacking in the design of online social network interventions for behavioral change. Existing theories and models from health psychology that are traditionally used for in situ behavioral change should be considered when designing online social network interventions in a health care setting. © 2016 John Wiley & Sons, Ltd.

  15. Meson-exchange currents and quasielastic predictions for charged-current neutrino-12C scattering in the superscaling approach

    CERN Document Server

    Megias, G D; Moreno, O; Williamson, C F; Caballero, J A; Gonzalez-Jimenez, R; De Pace, A; Barbaro, M B; Alberico, W M; Nardi, M; Amaro, J E

    2014-01-01

    We evaluate and discuss the impact of meson-exchange currents (MEC) on charged-current quasielastic (QE) neutrino cross sections. We consider the nuclear transverse response arising from 2p-2h states excited by the action of electromagnetic, purely isovector meson-exchange currents in a fully relativistic framework, based on the work by the Torino collaboration [1]. An accurate parametrization of this MEC response as a function of the momentum and energy transfers involved is presented. Results of neutrino-nucleus cross sections using this MEC parametrization together with a recent scaling approach for the 1p-1h contributions (SuSAv2) are compared with experimental data (MiniBooNE, MINERvA, NOMAD and T2K Collaborations).

  16. A game theoretical approach for QoS provisioning in heterogeneous networks

    Directory of Open Access Journals (Sweden)

    A.S.M. Zadid Shifat

    2015-09-01

    Full Text Available With the proliferation of mobile phone users, interference management is a big concern in this neoteric years. To cope with this problem along with ensuring better Quality of Service (QoS, femtocell plays an imperious preamble in heterogeneous networks (HetNets for some of its noteworthy characteristics. In this paper, we propose a game theoretic algorithm along with dynamic channel allocation and hybrid access mechanism with self-organizing power control scheme. With a view to resolving prioritized access issue, the concept of primary and secondary users is applied. Existence of pure strategy Nash equilibrium (NE has been investigated and comes to a perfection that our proposed scheme can be adopted both increasing capacity and increasing revenue of operators considering optimal price for consumers.

  17. Electrocaloric effect in core-shell ferroelectric ceramics: Theoretical approach and practical conclusions

    Science.gov (United States)

    Anoufa, M.; Kiat, J. M.; Bogicevic, C.

    2015-10-01

    Most of the theoretical and experimental studies on the electrocaloric effect (ECE) are devoted to thin films, but they can be hardly envisaged for cooling macroscopic systems; moreover, the results obtained cannot be easily transposed for larger systems like multilayered ceramics. Therefore, efforts should also be focused on predicting, synthesizing, and characterizing interesting bulk single crystal or ceramics. In ferroelectric nanoparticles and ceramics, the core-shell structure of grains is of uttermost importance to explain the experimental results at small sizes. Moreover, it can be used to tailor physical properties, such as energy storage, by experimenting with the composition, thickness, and permittivity of the shell. Here, we report the effect of such structures on the electrocaloric effects in a variety of ferroelectric materials. The magnitude of ECE as well as its field and temperature-dependence are obtained for different types of core-shells. The optimal configuration for a maximal ECE is deduced.

  18. Tractors and twistors from conformal Cartan geometry: a gauge theoretic approach II. Twistors

    Science.gov (United States)

    Attard, J.; François, J.

    2017-04-01

    Tractor and Twistor bundles provide natural conformally covariant calculi on 4D-Riemannian manifolds. They have different origins but are closely related, and usually constructed bottom–up through prolongation of defining differential equations. We propose alternative top–down gauge theoretic constructions, starting from the conformal Cartan bundle P and its vectorial E and spinorial {E associated bundles. Our key ingredient is the dressing field method of gauge symmetry reduction, which allows tractors and twistors and their associated connections to exhibit as gauge fields of a non-standard kind as far as Weyl rescaling transformation is concerned. By non-standard we mean that they implement the gauge principle of physics, but are of a different geometric nature than the well-known differential geometric objects usually underlying gauge theories. We provide the corresponding BRST treatment. In a companion paper we dealt with tractors, in the present one we address the case of twistors.

  19. Transmedial Worlds: Conceptual Review and Theoretical Approaches on the Art of Worldmaking

    Directory of Open Access Journals (Sweden)

    Nieves Rosendo Sánchez

    2016-01-01

    Full Text Available The concept of transmedia storytelling introduced by Henry Jenkins (2003, 2006 has been widely developed in the academic field, getting popular and being redefined with time. In transmedia storytelling’s definition we can observe the focus on the concept of world, which from a theoretical and critical perspective did not had the development that the relationship among narrative and media had. This work gathers and analyzes a selection of references from the main authors that have defined the nature, limits and transferability of the so called transmedial worlds, proposing conclusions related to the need to observe the phenomenon of transmedia narratives, its founding elements and the processes related to them, with the aim to elaborate a catalogue of criteria for the analysis and consideration of key element of transmedia storytelling.

  20. Fatigue study on the actuation performance of macro fiber composite (MFC): theoretical and experimental approach

    Science.gov (United States)

    Pandey, Akash; Arockiarajan, A.

    2017-03-01

    Macro fiber composite (MFC) is extensively used in vibration control and actuation applications due to its high flexibility and enhanced coupling coefficients. During these applications, MFCs are subjected to the continuous cyclic electrical loading, which may lead to the degradation in its actuation performance. In order to predict the life cycle of MFCs, an experimental setup has been devised and experiments are performed under cyclic loading condition. Efforts involved in the experiments are huge in terms of time and cost. Hence, an attempt has been made to develop a theoretical model to predict the fatigue behavior of MFCs. A nonlinear finite element method has been formulated based on Kirchhoff plate theory wherein the fatigue failure criterion based on strain energy is embedded. Simulated results based on the proposed model is compared with experimental observation and are in good agreement with each other. Variation in the life cycle of MFCs are also studied for different operating temperatures as well as structural/geometric configurations.

  1. Role of word-of-mouth for programs of voluntary vaccination: A game-theoretic approach.

    Science.gov (United States)

    Bhattacharyya, Samit; Bauch, Chris T; Breban, Romulus

    2015-11-01

    We propose a model describing the synergetic feedback between word-of-mouth (WoM) and epidemic dynamics controlled by voluntary vaccination. The key feature consists in combining a game-theoretic model for the spread of WoM and a compartmental model describing VSIR disease dynamics in the presence of a program of voluntary vaccination. We evaluate and compare two scenarios for determinants of behavior, depending on what WoM disseminates: (1) vaccine advertising, which may occur whether or not an epidemic is ongoing and (2) epidemic status, notably disease prevalence. Understanding the synergy between the two strategies could be particularly important for designing voluntary vaccination campaigns. We find that, in the initial phase of an epidemic, vaccination uptake is determined more by vaccine advertising than the epidemic status. As the epidemic progresses, epidemic status becomes increasingly important for vaccination uptake, considerably accelerating vaccination uptake toward a stable vaccination coverage.

  2. Planetary Nebulae as Tracers of the Intergalactic Stellar Background: a Population Synthesis Theoretical Approach

    CERN Document Server

    Buzzoni, A

    2004-01-01

    We wish to assess the relationship between the population of planetary nebulae (PNe) and a given parent stellar population from a theoretical point of view. Our results rely on original population synthesis models used to estimate the expected luminosity-specific PN density accounting for different evolutionary scenarios and star formation histories, as observed in galaxies in the near Universe. For a complete PN sample, we find that 1 PN/1.5E06 L(sun) a safe (IMF-independent) lower limit to the traced global bolometric luminosity of the parent stellar population. A tentative application to Virgo cluster data allows us to place a lower limit at ~7% for the global B luminosity of the cluster provided by "loose" intergalactic stars.

  3. The Theoretical Defects in DRIS and the Restructuring of a New Approach

    Institute of Scientific and Technical Information of China (English)

    LI Jian; LI Mei-gui

    2004-01-01

    There are two kinds of theoretical defects export in the diagnosis and recommendation integrated system(DRIS):the distribution of nutrient elements ratios with two normal distribution displays an abnormal distribution of positive skewness; there is a blind diagnostic area by DRIS on the occasion of the nutrient elements with equal ratios but without equal quantity.In the light of the quadratic form theory of multidimensional normal distribution and the view of balance of equal probability,the balance diagnosis and recommendationintegrated system(BDRIS)was developed in this paper,which is superior to DRIS and its diagnosis method is unified to critical value diagnosis.When the correlation matrix of nutrient elements R= I(identity matrix),i.e.,the effects of elements antagonism is disregarded,BDRIS will be simplified into the critical value diagnosis.In addition,the diagnosis program written in SAS language was also provided in this paper.

  4. On Innovation: A Theoretical Approach on the Challenges of Utilities Marketing

    Directory of Open Access Journals (Sweden)

    Florina PÎNZARU

    2012-06-01

    Full Text Available One of the markets not long ago closed and completely regulated is now in the growing process of liberalization and deregulation: it is the utilities market we refer to (water, sewege, gas, electricity, waste collection. The deregulation of a market is usually followed by the appearance of competition expression conditions and, unassailably, the occurrence of specific marketing strategies. This paper investigates the specific of utilities marketing as it develops now, an bourgeoning domain, although with a rather discreet presence in this field’s theoretical analysis studies. Exploratory research on the analysis type products, promotional offers and communication of this market’s players shows an effervescent players practice, but also a continuous innovation necessary in a market where consumers are unfamiliar with bein persuaded by commercial means

  5. Levels of integration of ICT in the curriculum: a theoretical approach

    Directory of Open Access Journals (Sweden)

    Sergio URUEÑA LÓPEZ

    2016-06-01

    Full Text Available The principal aim of this paper is to analyze from a theoretical point of view the triple dimension that implies the full integration of Information and Communications Technologies (ICT in the curriculum. The first level refers to the incorporation of ICT as didactic tools to support teaching practice. The second one alludes to the incorporation of ICT as a means for promote an efficient use of it. The third one suggests the incorporation of ICT as objects of critical analysis and knowledge. The last two mentioned dimensions –the most unnoticed but certainly not the least important– are essential for promoting critical citizens with the capacity to take reasonable and informed decisions regarding the assessment, design, monitoring and implementation of the new technologies.

  6. A dynamic systems approach to psychotherapy: A meta-theoretical framework for explaining psychotherapy change processes.

    Science.gov (United States)

    Gelo, Omar Carlo Gioacchino; Salvatore, Sergio

    2016-07-01

    Notwithstanding the many methodological advances made in the field of psychotherapy research, at present a metatheoretical, school-independent framework to explain psychotherapy change processes taking into account their dynamic and complex nature is still lacking. Over the last years, several authors have suggested that a dynamic systems (DS) approach might provide such a framework. In the present paper, we review the main characteristics of a DS approach to psychotherapy. After an overview of the general principles of the DS approach, we describe the extent to which psychotherapy can be considered as a self-organizing open complex system, whose developmental change processes are described in terms of a dialectic dynamics between stability and change over time. Empirical evidence in support of this conceptualization is provided and discussed. Finally, we propose a research design strategy for the empirical investigation of psychotherapy from a DS approach, together with a research case example. We conclude that a DS approach may provide a metatheoretical, school-independent framework allowing us to constructively rethink and enhance the way we conceptualize and empirically investigate psychotherapy. (PsycINFO Database Record

  7. A Standard Model—Theoretic Approach to Operational Semmantics of Recursiv Programs

    Institute of Scientific and Technical Information of China (English)

    邵志清

    1993-01-01

    In this paper we try to introduce a new approach to operational semantics of recursive programs by using ideas in the“priority method”which is a fundamental tool in Recursion Theory.In lieu of modelling partial functions by introducing undefined values in a traditional approach,we shall define a priority derivation tree for every term,and by respecting thr rule“attacking the subtem of the highest priority first”we define transition relations,computation sequences etc.directly based on a standard interpretation whic includes no undefined value in its domain,Finally,we prove that our new approach generates the same opeational semantics as the traditional one.It is also pointed out that we can use our strategy oto refute a claim of Loeckx and Sieber that the opperational semantics of recursive programs cannot be built based on predicate logic.

  8. Comparison of theoretical approaches for computing the bond length alternation of polymethineimine

    Energy Technology Data Exchange (ETDEWEB)

    Jacquemin, Denis [Laboratoire de Chimie Theorique Appliquee, Facultes Universitaires Notre-Dame de la Paix, rue de Bruxelles, 61, B-5000 Namur (Belgium)], E-mail: denis.jacquemin@fundp.ac.be; Perpete, Eric A. [Laboratoire de Chimie Theorique Appliquee, Facultes Universitaires Notre-Dame de la Paix, rue de Bruxelles, 61, B-5000 Namur (Belgium); Chermette, Henry [Laboratoire de Chimie Physique Theorique, Universite Claude Bernard, Lyon I Bat. 210, and CNRS UMR 5180 43, Boulevard du 11 Novembre 1918, F-69622 Villeurbanne Cedex (France); Ciofini, Ilaria; Adamo, Carlo [Ecole Nationale Superieure de Chimie de Paris, Laboratoire Electrochimie et Chimie Analytique, UMR CNRS ENSCP no. 7575, rue Pierre et Marie Curie, 11 F-75321 Paris Cedex 05 (France)

    2007-01-25

    Using electron-correlated wavefunction approaches and several pure and hybrid density functionals combined with three atomic basis sets, we have optimized the ground-state geometry of increasingly long polymethineimine oligomers presenting all-trans and gliding-plane symmetries. It turns out that MP2 bond length alternations (BLA) are in good agreement with higher-order electron-correlated wavefunction approaches, whereas, for both conformers, large qualitative and quantitative discrepancies between MP2 and DFT geometries have been found. Indeed, all the selected GGA, meta-GGA and hybrid functionals tend to overestimate bond length equalization in extended polymethineimine structures. On the other hand, self-interaction corrections included in the ADSIC framework provide, in this particular case, a more efficient approach to predict the BLA for medium-size oligomers.

  9. Comparison of theoretical approaches for computing the bond length alternation of polymethineimine

    Science.gov (United States)

    Jacquemin, Denis; Perpète, Eric A.; Chermette, Henry; Ciofini, Ilaria; Adamo, Carlo

    2007-01-01

    Using electron-correlated wavefunction approaches and several pure and hybrid density functionals combined with three atomic basis sets, we have optimized the ground-state geometry of increasingly long polymethineimine oligomers presenting all- trans and gliding-plane symmetries. It turns out that MP2 bond length alternations (BLA) are in good agreement with higher-order electron-correlated wavefunction approaches, whereas, for both conformers, large qualitative and quantitative discrepancies between MP2 and DFT geometries have been found. Indeed, all the selected GGA, meta-GGA and hybrid functionals tend to overestimate bond length equalization in extended polymethineimine structures. On the other hand, self-interaction corrections included in the ADSIC framework provide, in this particular case, a more efficient approach to predict the BLA for medium-size oligomers.

  10. Organizations in context: proposal for a new theoretical approach in prescriptive accident research

    DEFF Research Database (Denmark)

    Dyhrberg, Mette Bang; Jensen, Per Langå

    2004-01-01

    between understanding the processes in the enterprises and understanding the contextual relations. Decision-making theories are used to explain the internal processes. And regulatory approaches are used to describe the role of the state in regard to accident prevention in enterprises. Eventually......, contextual theories are presented as theories to perceive the relation between enterprise and context. The conclusion is that there is a basis for using contextual theories in a new approach, but also an investigation of the potentials for making the theories action-orientated is needed....

  11. Psychological resilience: an approach to the concept, theoretical framework and relation with child sexual abuse

    Directory of Open Access Journals (Sweden)

    Cristian Gustavo Pinto-Cortez

    2014-11-01

    Full Text Available Child sexual abuse is a serious public health problem and a violation of human rights from children and adolescents. A prolific research has been developed to determine the magnitude of the problem, psychological effects, risk factors and protective factors. In this context, resilience approach becomes important by explain the mechanisms that promote positive adaptation to adversity. In this paper, it is discussed in the first part, the analysis of the concept of resilience and its various stages of investigation over time. Finally, an integration of this model in understanding and approaching child and adolescent victimization is done.

  12. THEORETICAL APPROACHES TO THE CONCEPT OF INTELLECTUAL PRODUCT AND ITS RELATIONSHIP TO SCIENTIFIC RESEARCH OF HIGHER EDUCATION OF THE REGION

    Directory of Open Access Journals (Sweden)

    Andrej B. Ilin

    2014-01-01

    Full Text Available The article reveals the essence of the intellectual product, its relationship with research of higher schools in the region, the role of intellectual property in the development of innovative capacity of the region. It also contains the author’s definition of an intellectual product of Higher Education, a classification of intellectual products. Based on the analysis of existing theoretical approaches and regional practices, relations between concepts «intellectual product», «intellectual work», «intellectual capital» and «intellectual property» are especially highlighted by the author.

  13. Incorporating Short Term Dynamic Psychotherapy Principles into Career Counseling: A Theoretical and Practical Approach.

    Science.gov (United States)

    Nevo, Ofra; Wiseman, Hadas

    2002-01-01

    The Developmental Career Counseling model incorporates the following principles of Short-Term Dynamic Psychotherapy: life-span approach, limited time, working alliance, rapid and early assessment, central focus, active and directive counselor participation, therapeutic flexibility, and termination issues. The model enables career and personal…

  14. Theoretic-methodological approaches to determine the content and classification of innovation-investment development strategies

    Directory of Open Access Journals (Sweden)

    Gerashenkova Tatyana

    2016-01-01

    Full Text Available The article states the necessity to form an innovation-investment strategy of enterprise development, offers an approach to its classification, determines the place of this strategy in a corporatewide strategy, gives the methodology of formation and the realization form of the innovation-investment development strategy.

  15. Field Theory in Organizational Psychology: An Analysis of Theoretical Approaches in Leadership.

    Science.gov (United States)

    Garcia, Joseph E.

    This literature review examines Kurt Lewin's influence in leadership psychology. Characteristics of field theory are described in detail and utilized in analyzing leadership research, including the trait approach, leader behavior studies, contingency theory, path-goal theory, and leader decision theory. Important trends in leadership research are…

  16. A Theoretical Framework for Media Law Courses (Approaches to Teaching Freedom of Expression).

    Science.gov (United States)

    Helle, Steven

    1991-01-01

    Suggests that most students prefer teachers have a theme that provides coherence and cohesiveness to media law courses. Explains how libertarian and neoliberal themes can guide learning and enumerates some of the principles of the two theories. Identifies drawbacks of the case analysis approach to such courses. (SG)

  17. A Mindfulness-Acceptance-Commitment-Based Approach to Athletic Performance Enhancement: Theoretical Considerations

    Science.gov (United States)

    Gardner, Frank L.; Moore, Zella E.

    2004-01-01

    While traditional cognitive-behavioral skills-training-based approaches to athletic performance enhancement posit that negative thoughts and emotions must be controlled, eliminated, or replaced for athlete-clients to perform optimally, recent evidence suggests that efforts to control, eliminate, or suppress these internal states may actually have…

  18. Field Theory in Organizational Psychology: An Analysis of Theoretical Approaches in Leadership.

    Science.gov (United States)

    Garcia, Joseph E.

    This literature review examines Kurt Lewin's influence in leadership psychology. Characteristics of field theory are described in detail and utilized in analyzing leadership research, including the trait approach, leader behavior studies, contingency theory, path-goal theory, and leader decision theory. Important trends in leadership research are…

  19. Merged ontology for engineering design: Contrasting empirical and theoretical approaches to develop engineering ontologies

    DEFF Research Database (Denmark)

    Ahmed, Saeema; Storga, M

    2009-01-01

    This paper presents a comparison of two previous and separate efforts to develop an ontology in the engineering design domain, together with an ontology proposal from which ontologies for a specific application may be derived. The research contrasts an empirical, user-centered approach to develop...

  20. Elements of a flexible approach for conceptual hydrological modeling: 1. Motivation and theoretical development

    NARCIS (Netherlands)

    Fenicia, F.; Kavetski, D.; Savenije, H.H.G.

    2011-01-01

    This paper introduces a flexible framework for conceptual hydrological modeling, with two related objectives: (1) generalize and systematize the currently fragmented field of conceptual models and (2) provide a robust platform for understanding and modeling hydrological systems. In contrast to curre

  1. An Integrative Approach to Curriculum Development in Higher Education in the USA: A Theoretical Framework

    Science.gov (United States)

    Khan, Mohammad Ayub; Law, Laurie Smith

    2015-01-01

    The role of curriculum in higher education is sine quo non for the provision of quality and relevant educational programs and services to the current and potential learners in the USA and elsewhere in the world. Regardless of sizes, types or origins, curriculum is considered the heart and soul of all educational institutions. Curriculum is crucial…

  2. A Network Approach to Environmental Impact in Psychotic Disorder : Brief Theoretical Framework

    NARCIS (Netherlands)

    Isvoranu, A.M.; Borsboom, D.; van Os, J.; Guloksuz, S.

    2016-01-01

    The spectrum of psychotic disorder represents a multifactorial and heterogeneous condition and is thought to result from a complex interplay between genetic and environmental factors. In the current paper, we analyze this interplay using network analysis, which has been recently proposed as a novel

  3. Laser cooling of MgCl and MgBr in theoretical approach

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Mingjie; Shao, Juxiang; Huang, Duohui; Yang, Junsheng; Cao, Qilong; Jin, Chengguo; Wang, Fanhou, E-mail: fanhouwangyibin@163.com [Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin 644007 (China); Gao, Yufeng [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China)

    2015-07-14

    Ab initio calculations for three low-lying electronic states (X{sup 2}Σ{sup +}, A{sup 2}Π, and 2{sup 2}Π) of MgCl and MgBr molecules, including spin-orbit coupling, are performed using multi-reference configuration interaction plus Davidson correction method. The calculations involve all-electronic basis sets and Douglas–Kroll scalar relativistic correction. Spectroscopic parameters well agree with available theoretical and experimental data. Highly diagonally distributed Franck-Condon factors f{sub 00} for A{sup 2}Π{sub 3/2,1/2} (υ′ = 0) → X{sup 2}Σ{sup +}{sub 1/2} (υ″ = 0) are determined for both MgCl and MgBr molecules. Suitable radiative lifetimes τ of A{sup 2}Π{sub 3/2,1/2} (υ′ = 0) states for rapid laser cooling are also obtained. The proposed laser drives A{sup 2}Π{sub 3/2} (υ′ = 0) → X{sup 2}Σ{sup +}{sub 1/2} (υ″ = 0) transition by using three wavelengths (main pump laser λ{sub 00}; two repumping lasers λ{sub 10} and λ{sub 21}). These results indicate the probability of laser cooling MgCl and MgBr molecules.

  4. An information theoretic approach to select alternate subsets of predictors for data-driven hydrological models

    Science.gov (United States)

    Taormina, R.; Galelli, S.; Karakaya, G.; Ahipasaoglu, S. D.

    2016-11-01

    This work investigates the uncertainty associated to the presence of multiple subsets of predictors yielding data-driven models with the same, or similar, predictive accuracy. To handle this uncertainty effectively, we introduce a novel input variable selection algorithm, called Wrapper for Quasi Equally Informative Subset Selection (W-QEISS), specifically conceived to identify all alternate subsets of predictors in a given dataset. The search process is based on a four-objective optimization problem that minimizes the number of selected predictors, maximizes the predictive accuracy of a data-driven model and optimizes two information theoretic metrics of relevance and redundancy, which guarantee that the selected subsets are highly informative and with little intra-subset similarity. The algorithm is first tested on two synthetic test problems and then demonstrated on a real-world streamflow prediction problem in the Yampa River catchment (US). Results show that complex hydro-meteorological datasets are characterized by a large number of alternate subsets of predictors, which provides useful insights on the underlying physical processes. Furthermore, the presence of multiple subsets of predictors-and associated models-helps find a better trade-off between different measures of predictive accuracy commonly adopted for hydrological modelling problems.

  5. A game theoretical approach to the evolution of structured communication codes.

    Science.gov (United States)

    Fontanari, José F; Perlovsky, Leonid I

    2008-08-01

    Structured meaning-signal mappings, i.e., mappings that preserve neighborhood relationships by associating similar signals with similar meanings, are advantageous in an environment where signals are corrupted by noise and sub-optimal meaning inferences are rewarded as well. The evolution of these mappings, however, cannot be explained within a traditional language evolutionary game scenario in which individuals meet randomly because the evolutionary dynamics is trapped in local maxima that do not reflect the structure of the meaning and signal spaces. Here we use a simple game theoretical model to show analytically that when individuals adopting the same communication code meet more frequently than individuals using different codes-a result of the spatial organization of the population-then advantageous linguistic innovations can spread and take over the population. In addition, we report results of simulations in which an individual can communicate only with its K nearest neighbors and show that the probability that the lineage of a mutant that uses a more efficient communication code becomes fixed decreases exponentially with increasing K. These findings support the mother tongue hypothesis that human language evolved as a communication system used among kin, especially between mothers and offspring.

  6. Solubility of caffeine from green tea in supercritical CO2: a theoretical and empirical approach.

    Science.gov (United States)

    Gadkari, Pravin Vasantrao; Balaraman, Manohar

    2015-12-01

    Decaffeination of fresh green tea was carried out with supercritical CO2 in the presence of ethanol as co-solvent. The solubility of caffeine in supercritical CO2 varied from 44.19 × 10(-6) to 149.55 × 10(-6) (mole fraction) over a pressure and temperature range of 15 to 35 MPa and 313 to 333 K, respectively. The maximum solubility of caffeine was obtained at 25 MPa and 323 K. Experimental solubility data were correlated with the theoretical equation of state models Peng-Robinson (PR), Soave Redlich-Kwong (SRK), and Redlich-Kwong (RK). The RK model had regressed experimental data with 15.52 % average absolute relative deviation (AARD). In contrast, Gordillo empirical model regressed the best to experimental data with only 0.96 % AARD. Under supercritical conditions, solubility of caffeine in tea matrix was lower than the solubility of pure caffeine. Further, solubility of caffeine in supercritical CO2 was compared with solubility of pure caffeine in conventional solvents and a maximum solubility 90 × 10(-3) mol fraction was obtained with chloroform.

  7. Diagnostic yield of targeted next generation sequencing in various cancer types: an information-theoretic approach.

    Science.gov (United States)

    Hagemann, Ian S; O'Neill, Patrick K; Erill, Ivan; Pfeifer, John D

    2015-09-01

    The information-theoretic concept of Shannon entropy can be used to quantify the information provided by a diagnostic test. We hypothesized that in tumor types with stereotyped mutational profiles, the results of NGS testing would yield lower average information than in tumors with more diverse mutations. To test this hypothesis, we estimated the entropy of NGS testing in various cancer types, using results obtained from clinical sequencing. A set of 238 tumors were subjected to clinical targeted NGS across all exons of 27 genes. There were 120 actionable variants in 109 cases, occurring in the genes KRAS, EGFR, PTEN, PIK3CA, KIT, BRAF, NRAS, IDH1, and JAK2. Sequencing results for each tumor were modeled as a dichotomized genotype (actionable mutation detected or not detected) for each of the 27 genes. Based upon the entropy of these genotypes, sequencing was most informative for colorectal cancer (3.235 bits of information/case) followed by high grade glioma (2.938 bits), lung cancer (2.197 bits), pancreatic cancer (1.339 bits), and sarcoma/STTs (1.289 bits). In the most informative cancer types, the information content of NGS was similar to surgical pathology examination (modeled at approximately 2-3 bits). Entropy provides a novel measure of utility for laboratory testing in general and for NGS in particular. This metric is, however, purely analytical and does not capture the relative clinical significance of the identified variants, which may also differ across tumor types.

  8. Relativistic many-body theory a new field-theoretical approach

    CERN Document Server

    Lindgren, Ingvar

    2016-01-01

    This revised second edition of the author’s classic text offers readers a comprehensively updated review of relativistic atomic many-body theory, covering the many developments in the field since the publication of the original title.  In particular, a new final section extends the scope to cover the evaluation of QED effects for dynamical processes. The treatment of the book is based upon quantum-field theory, and demonstrates that when the procedure is carried to all orders of perturbation theory, two-particle systems are fully compatible with the relativistically covariant Bethe-Salpeter equation. This procedure can be applied to arbitrary open-shell systems, in analogy with the standard many-body theory, and it is also applicable to systems with more than two particles. Presently existing theoretical procedures for treating atomic systems are, in several cases, insufficient to explain the accurate experimental data recently obtained, particularly for highly charged ions. The main text is divided into...

  9. An Estimation Theoretic Approach for Sparsity Pattern Recovery in the Noisy Setting

    CERN Document Server

    Hormati, Ali; Mohajer, Soheil; Vetterli, Martin

    2009-01-01

    Compressed sensing deals with the reconstruction of sparse signals using a small number of linear measurements. One of the main challenges in compressed sensing is to find the support of a sparse signal. In the literature, several bounds on the scaling law of the number of measurements for successful support recovery have been derived where the main focus is on random Gaussian measurement matrices. In this paper, we investigate the noisy support recovery problem from an estimation theoretic point of view, where no specific assumption is made on the underlying measurement matrix. The linear measurements are perturbed by additive white Gaussian noise. We define the output of a support estimator to be a set of position values in increasing order. We set the error between the true and estimated supports as the $\\ell_2$-norm of their difference. On the one hand, this choice allows us to use the machinery behind the $\\ell_2$-norm error metric and on the other hand, converts the support recovery into a more intuitiv...

  10. Information theoretical approach to discovering solar wind drivers of the outer radiation belt

    Science.gov (United States)

    Wing, Simon; Johnson, Jay R.; Camporeale, Enrico; Reeves, Geoffrey D.

    2016-10-01

    The solar wind-magnetosphere system is nonlinear. The solar wind drivers of geosynchronous electrons with energy range of 1.8-3.5 MeV are investigated using mutual information, conditional mutual information (CMI), and transfer entropy (TE). These information theoretical tools can establish linear and nonlinear relationships as well as information transfer. The information transfer from solar wind velocity (Vsw) to geosynchronous MeV electron flux (Je) peaks with a lag time of 2 days. As previously reported, Je is anticorrelated with solar wind density (nsw) with a lag of 1 day. However, this lag time and anticorrelation can be attributed at least partly to the Je(t + 2 days) correlation with Vsw(t) and nsw(t + 1 day) anticorrelation with Vsw(t). Analyses of solar wind driving of the magnetosphere need to consider the large lag times, up to 3 days, in the (Vsw, nsw) anticorrelation. Using CMI to remove the effects of Vsw, the response of Je to nsw is 30% smaller and has a lag time Je. Nonstationarity in the system dynamics is investigated using windowed TE. When the data are ordered according to transfer entropy value, it is possible to understand details of the triangle distribution that has been identified between Je(t + 2 days) versus Vsw(t).

  11. Annual Gross Primary Production from Vegetation Indices: A Theoretically Sound Approach

    Directory of Open Access Journals (Sweden)

    María Amparo Gilabert

    2017-02-01

    Full Text Available A linear relationship between the annual gross primary production (GPP and a PAR-weighted vegetation index is theoretically derived from the Monteith equation. A semi-empirical model is then proposed to estimate the annual GPP from commonly available vegetation indices images and a representative PAR, which does not require actual meteorological data. A cross validation procedure is used to calibrate and validate the model predictions against reference data. As the calibration/validation process depends on the reference GPP product, the higher the quality of the reference GPP, the better the performance of the semi-empirical model. The annual GPP has been estimated at 1-km scale from MODIS NDVI and EVI images for eight years. Two reference data sets have been used: an optimized GPP product for the study area previously obtained and the MOD17A3 product. Different statistics show a good agreement between the estimates and the reference GPP data, with correlation coefficient around 0.9 and relative RMSE around 20%. The annual GPP is overestimated in semiarid areas and slightly underestimated in dense forest areas. With the above limitations, the model provides an excellent compromise between simplicity and accuracy for the calculation of long time series of annual GPP.

  12. An experimental and theoretical approach to the study of the photoacoustic signal produced by cancer cells

    Directory of Open Access Journals (Sweden)

    Rafael Pérez Solano

    2012-03-01

    Full Text Available The distinctive spectral absorption characteristics of cancer cells make photoacoustic techniques useful for detection in vitro and in vivo. Here we report on our evaluation of the photoacoustic signal produced by a series of monolayers of different cell lines in vitro. Only the melanoma cell line HS936 produced a detectable photoacoustic signal in which amplitude was dependent on the number of cells. This finding appears to be related to the amount of melanin available in these cells. Other cell lines (i.e. HL60, SK-Mel-1, T47D, Hela, HT29 and PC12 exhibited values similar to a precursor of melanin (tyrosinase, but failed to produce sufficient melanin to generate a photoacoustic signal that could be distinguished from background noise. To better understand this phenomenon, we determined a formula for the time-domain photoacoustic wave equation for a monolayer of cells in a non-viscous fluid on the thermoelastic regime. The theoretical results showed that the amplitude and profile of the photoacoustic signal generated by a cell monolayer depended upon the number and distribution of the cells and the location of the point of detection. These findings help to provide a better understanding of the factors involved in the generation of a photoacoustic signal produced by different cells in vitro and in vivo.

  13. Information Theoretic Approaches to Rapid Discovery of Relationships in Large Climate Data Sets

    Science.gov (United States)

    Knuth, Kevin H.; Rossow, William B.; Clancy, Daniel (Technical Monitor)

    2002-01-01

    Mutual information as the asymptotic Bayesian measure of independence is an excellent starting point for investigating the existence of possible relationships among climate-relevant variables in large data sets, As mutual information is a nonlinear function of of its arguments, it is not beholden to the assumption of a linear relationship between the variables in question and can reveal features missed in linear correlation analyses. However, as mutual information is symmetric in its arguments, it only has the ability to reveal the probability that two variables are related. it provides no information as to how they are related; specifically, causal interactions or a relation based on a common cause cannot be detected. For this reason we also investigate the utility of a related quantity called the transfer entropy. The transfer entropy can be written as a difference between mutual informations and has the capability to reveal whether and how the variables are causally related. The application of these information theoretic measures is rested on some familiar examples using data from the International Satellite Cloud Climatology Project (ISCCP) to identify relation between global cloud cover and other variables, including equatorial pacific sea surface temperature (SST), over seasonal and El Nino Southern Oscillation (ENSO) cycles.

  14. A Game-Theoretic Approach to Energy-Efficient Modulation in CDMA Networks with Delay Constraints

    CERN Document Server

    Meshkati, Farhad; Poor, H Vincent; Schwartz, Stuart C

    2007-01-01

    A game-theoretic framework is used to study the effect of constellation size on the energy efficiency of wireless networks for M-QAM modulation. A non-cooperative game is proposed in which each user seeks to choose its transmit power (and possibly transmit symbol rate) as well as the constellation size in order to maximize its own utility while satisfying its delay quality-of-service (QoS) constraint. The utility function used here measures the number of reliable bits transmitted per joule of energy consumed, and is particularly suitable for energy-constrained networks. The best-response strategies and Nash equilibrium solution for the proposed game are derived. It is shown that in order to maximize its utility (in bits per joule), a user must choose the lowest constellation size that can accommodate the user's delay constraint. Using this framework, the tradeoffs among energy efficiency, delay, throughput and constellation size are also studied and quantified. The effect of trellis-coded modulation on energy...

  15. [Specific developmental language disorder: a theoretical approach to its diagnosis, aetiology and clinical symptoms].

    Science.gov (United States)

    Castro-Rebolledo, R; Giraldo-Prieto, M; Hincapié-Henao, L; Lopera, F; Pineda, D A

    This article presents an updated review about the definition, diagnostic criteria, classifications, etiology and the evolution of the specific language impairment (SLI). The specific language impairment is characterized by a developmental language delay and an impaired language, that persist over time and it is not explained by sensorial, motor and mental disabilities, neither by psycopathological disorders, socio-emotional deprivation, nor brain injury. The diagnosis is based on exclusional criteria. Some researchers propose different classifications considering the children performance in language comprehension and language production. Genetical linkage to the FOXP2 gen in the SPCH1 region of the chromosome 7 and to the chromosomes 13, 16 y 19 has been reported. The neuroimage studies have shown alterations in the volume and perfusion of some brain structures related to language. The manifestations of SLI may change during the development of the children and may disturb the self-esteem, the academic performance and the social abilities. The variability in the linguistic and cognitive performance, and the variety in the etiological findings in children with SLI, don't allow to settle the affected population as an homogeneous group. Different theoretical positions have emerged as a consequence of this condition.

  16. Theoretical approaches of semiconductor interfaces and of their defects : recent developments

    Science.gov (United States)

    Priester, C.

    1991-04-01

    We describe recent developments of theoretical studies concerning semiconductor interfaces from different points of view: the widely used effective mass approximation and its limitations are considered ; different ways to calculate band offsets are described and compared; the interesting problem of the effect of strains is discussed; several interface defects that have been recently studied are also considered. Nous donnons ici une revue des diverses études théoriques sur les interfaces de semiconducteurs et leurs défauts. Divers aspects sont considérés: d'une part le problème délicat de l'approximation de la masse effective (utilisée très fréquemment) et de ses limitations ; d'autre part nous passons en revue les différentes approches possibles pour le calcul des discontinuités de bandes à l'hétérojonction ; une attention particulière est accordée aux modifications apportées par la présence d'une contrainte biaxiale (due à un désaccord de maille); enfin divers défauts localisés à l'interface, qui ont fait l'objet d'études récentes, sont pris en compte.

  17. A Bayesian Decision-Theoretic Approach to Logically-Consistent Hypothesis Testing

    Directory of Open Access Journals (Sweden)

    Gustavo Miranda da Silva

    2015-09-01

    Full Text Available This work addresses an important issue regarding the performance of simultaneous test procedures: the construction of multiple tests that at the same time are optimal from a statistical perspective and that also yield logically-consistent results that are easy to communicate to practitioners of statistical methods. For instance, if hypothesis A implies hypothesis B, is it possible to create optimal testing procedures that reject A whenever they reject B? Unfortunately, several standard testing procedures fail in having such logical consistency. Although this has been deeply investigated under a frequentist perspective, the literature lacks analyses under a Bayesian paradigm. In this work, we contribute to the discussion by investigating three rational relationships under a Bayesian decision-theoretic standpoint: coherence, invertibility and union consonance. We characterize and illustrate through simple examples optimal Bayes tests that fulfill each of these requisites separately. We also explore how far one can go by putting these requirements together. We show that although fairly intuitive tests satisfy both coherence and invertibility, no Bayesian testing scheme meets the desiderata as a whole, strengthening the understanding that logical consistency cannot be combined with statistical optimality in general. Finally, we associate Bayesian hypothesis testing with Bayes point estimation procedures. We prove the performance of logically-consistent hypothesis testing by means of a Bayes point estimator to be optimal only under very restrictive conditions.

  18. Free radical scavenging and COX-2 inhibition by simple colon metabolites of polyphenols: A theoretical approach.

    Science.gov (United States)

    Amić, Ana; Marković, Zoran; Marković, Jasmina M Dimitrić; Jeremić, Svetlana; Lučić, Bono; Amić, Dragan

    2016-12-01

    Free radical scavenging and inhibitory potency against cyclooxygenase-2 (COX-2) by two abundant colon metabolites of polyphenols, i.e., 3-hydroxyphenylacetic acid (3-HPAA) and 4-hydroxyphenylpropionic acid (4-HPPA) were theoretically studied. Different free radical scavenging mechanisms are investigated in water and pentyl ethanoate as a solvent. By considering electronic properties of scavenged free radicals, hydrogen atom transfer (HAT) and sequential proton loss electron transfer (SPLET) mechanisms are found to be thermodynamically probable and competitive processes in both media. The Gibbs free energy change for reaction of inactivation of free radicals indicates 3-HPAA and 4-HPPA as potent scavengers. Their reactivity toward free radicals was predicted to decrease as follows: hydroxyl>alkoxyls>phenoxyl≈peroxyls>superoxide. Shown free radical scavenging potency of 3-HPAA and 4-HPPA along with their high μM concentration produced by microbial colon degradation of polyphenols could enable at least in situ inactivation of free radicals. Docking analysis with structural forms of 3-HPAA and 4-HPPA indicates dianionic ligands as potent inhibitors of COX-2, an inducible enzyme involved in colon carcinogenesis. Obtained results suggest that suppressing levels of free radicals and COX-2 could be achieved by 3-HPAA and 4-HPPA indicating that these compounds may contribute to reduced risk of colon cancer development. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Experimental and theoretical approaches for Cd(II) biosorption from aqueous solution using Oryza sativa biomass.

    Science.gov (United States)

    Fawzy, Manal; Nasr, Mahmoud; Helmi, Shacker; Nagy, Heba

    2016-11-01

    Biomass of Oryza sativa (OS) was tested for the removal of Cd(II) ions from synthetic and real wastewater samples. Batch experiments were conducted to investigate the effects of operating parameters on Cd(II) biosorption. Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive x-ray spectroscopy were used to examine the surface characteristics of the Cd(II)-loaded biomass. The maximum removal efficiency of Cd(II) was 89.4% at optimum pH 6.0, biosorbent dose 10.0 g L(-1), initial Cd(II) 50 mg L(-1), and biosorbent particle size 0.5 mm. The applicability of Langmuir and Freundlich isotherms to the sorbent system implied the existence of both monolayer and heterogeneous surface conditions. Kinetic studies revealed that the adsorption process of Cd(II) followed the pseudo-second-order model (r2: 0.99). On the theoretical side, an adaptive neuro-fuzzy inference system (ANFIS) was applied to select the operating parameter that mostly influences the Cd(II) biosorption process. Results from ANFIS indicated that pH was the most influential parameter affecting Cd(II) removal efficiency, indicating that the biomass of OS was strongly pH sensitive. Finally, the biomass was confirmed to adsorb Cd(II) from real wastewater samples with removal efficiency close to 100%. However, feasibility studies of such systems on a large-scale application remain to be investigated.

  20. A Novel Information-Theoretic Approach for Variable Clustering and Predictive Modeling Using Dirichlet Process Mixtures

    Science.gov (United States)

    Chen, Yun; Yang, Hui

    2016-12-01

    In the era of big data, there are increasing interests on clustering variables for the minimization of data redundancy and the maximization of variable relevancy. Existing clustering methods, however, depend on nontrivial assumptions about the data structure. Note that nonlinear interdependence among variables poses significant challenges on the traditional framework of predictive modeling. In the present work, we reformulate the problem of variable clustering from an information theoretic perspective that does not require the assumption of data structure for the identification of nonlinear interdependence among variables. Specifically, we propose the use of mutual information to characterize and measure nonlinear correlation structures among variables. Further, we develop Dirichlet process (DP) models to cluster variables based on the mutual-information measures among variables. Finally, orthonormalized variables in each cluster are integrated with group elastic-net model to improve the performance of predictive modeling. Both simulation and real-world case studies showed that the proposed methodology not only effectively reveals the nonlinear interdependence structures among variables but also outperforms traditional variable clustering algorithms such as hierarchical clustering.