ADOPTING SOCIO-DEMOGRAPHIC CHARACTERISTICS IN PROFILING GREEN CONSUMERS: A REVIEW OF HYPOTHESES

Directory of Open Access Journals (Sweden)

Arif Hartono

2009-02-01

Full Text Available In the last three decades worldwide environmental consciousness has increased dramatically as well as profiling green consumers have gained tremendous attention in the past. Segmenting and targeting markets base on pro-environmental purchase behavior are essential when companies positioning their green products. Socio-demographic characteristics have gained a lot of attention as the key profiling variables. Such characteristics have been employed by many scholars more frequently for the bases of segmenting and profiling green consumers. However, most existing studies of green consumers’ socio-demographic were US based. The present article attempts to review the common hypotheses of socio-demographic characteristics in profiling green consumers. The present article reviews five general hypotheses relating to socio-demographics and environmental consciousness of green consumers, namely the gender, age, education level, income, and occupation hypotheses, as well as the theoretical explanation for each hypothesis. Most previous studies tend to have the same conclusion in the gender, age, education level, and  income characteristics. Critics to socio-demographic characteristics and a need to conduct green marketing research in Indonesia was also reviewed.Key words: profiling, socio-demographic, green consumer, hypotheses.

A Holistic Theoretical Approach to Intellectual Disability: Going beyond the Four Current Perspectives

Science.gov (United States)

Schalock, Robert L.; Luckasson, Ruth; Tassé, Marc J.; Verdugo, Miguel Angel

2018-01-01

This article describes a holistic theoretical framework that can be used to explain intellectual disability (ID) and organize relevant information into a usable roadmap to guide understanding and application. Developing the framework involved analyzing the four current perspectives on ID and synthesizing this information into a holistic…

Physical Violence between Siblings: A Theoretical and Empirical Analysis

Science.gov (United States)

Hoffman, Kristi L.; Kiecolt, K. Jill; Edwards, John N.

2005-01-01

This study develops and tests a theoretical model to explain sibling violence based on the feminist, conflict, and social learning theoretical perspectives and research in psychology and sociology. A multivariate analysis of data from 651 young adults generally supports hypotheses from all three theoretical perspectives. Males with brothers have…

Thermoelectric Generation Of Current – Theoretical And Experimental Analysis

Directory of Open Access Journals (Sweden)

Ruciński Adam

2017-12-01

Full Text Available This paper provides some information about thermoelectric technology. Some new materials with improved figures of merit are presented. These materials in Peltier modules make it possible to generate electric current thanks to a temperature difference. The paper indicates possible applications of thermoelectric modules as interesting tools for using various waste heat sources. Some zero-dimensional equations describing the conditions of electric power generation are given. Also, operating parameters of Peltier modules, such as voltage and electric current, are analyzed. The paper shows chosen characteristics of power generation parameters. Then, an experimental stand for ongoing research and experimental measurements are described. The authors consider the resistance of a receiver placed in the electric circuit with thermoelectric elements. Finally, both the analysis of experimental results and conclusions drawn from theoretical findings are presented. Voltage generation of about 1.5 to 2.5 V for the temperature difference from 65 to 85 K was observed when a bismuth telluride thermoelectric couple (traditionally used in cooling technology was used.

Using Transcranial tDCS to test cognitive hypotheses

Directory of Open Access Journals (Sweden)

Nazbanou Nozari

2014-04-01

Full Text Available Transcranial Direct Current Stimulation (tDCS is used increasingly often for testing cognitive hypotheses. It is, however, often ignored that many assumptions regarding how the neural tissue reacts to stimulation have only been verified in the motor domain. Extrapolating these assumptions to the cognitive domain has a set of unique issues which, if ignored, can lead to incorrect interpretations. In this talk I will review a number of common pitfalls in using tDCS for testing a cognitive hypothesis, and discuss some solutions for better-controlled designs. I will address the following issues: 1- Making an incorrect assumption about the nature of the effect: It is often assumed that anodal stimulation has “excitatory” and cathodal stimulation has “inhibitory” effects. Results are then interpreted in light of this assumption. Obviously, if the assumption is incorrect, the interpretation of the results too will be incorrect. I will discuss how the effects of polarity can change as a function of a number of design parameters, and the dangers of making a priori assumptions about the direction of stimulation effects, especially when employing a new design. 2- Choosing an inappropriate montage: By definition, tDCS requires two electrodes, although we are often only interested in stimulating one brain region. Where the second (reference electrode is placed may not be of theoretical interest to us, but it can have serious consequences for our effects of interest. For one thing the path of the direct current changes as a function of where the reference electrode is placed. This affects the density of the current, as well as the regions that undergo stimulation. Moreover, the region directly under the reference electrode is very likely to be affected by stimulation. Therefore, sometimes the changes in behavior may be due to the unanticipated effects at the reference electrode site, as opposed to the hypothesized effects at the target electrode site

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.

Preliminary testing of flow-ecology hypotheses developed for the GCP LCC region

Science.gov (United States)

Brewer, Shannon K.; Davis, Mary

2014-01-01

The Ecological Limits of Hydrological Alteration (ELOHA) framework calls for the development of flow-ecology hypotheses to support protection of the flow regime from ecologically harmful alteration due to human activities. As part of a larger instream flow project for the Gulf Coast Prairie Landscape Conservation Cooperative (GCP LCC), regional flow-ecology hypotheses were developed for fish, mussels, birds, and riparian vegetation (Davis and Brewer 20141). The objective of this study was to assess the usefulness of existing ecological and hydrological data to test these hypotheses or others that may be developed in the future. Several databases related to biological collections and hydrologic data from Oklahoma, Texas, and Louisiana were compiled. State fish-community data from Oklahoma and Louisiana were summarized and paired with existing USGS gage data having at least a 40-year period of record that could be separated into reference and current conditions for comparison. The objective of this study was not to conduct exhaustive analyses of these data, the hypotheses, or analyses interpretation, but rather to use these data to determine if existing data were adequate to statistically test the regional flow-ecology hypotheses. The regional flow-ecology hypotheses were developed for the GCP LCC by a committee chaired by Shannon Brewer and Mary Davis (Davis and Brewer 2014). Existing data were useful for informing the hypotheses and suggest support for some hypotheses, but also highlight the need for additional testing and development as some results contradicted hypotheses. Results presented here suggest existing data are adequate to support some flow-ecology hypotheses; however, lack of sampling effort reported with the fish collections and the need for ecoregion-specific analyses suggest more data would be beneficial to analyses in some ecoregions. Additional fish sampling data from Texas and Louisiana will be available for future analyses and may ameliorate

ITSSOIN Hypotheses

NARCIS (Netherlands)

Anheier, H.K.; Krlev, G.; Preuss, S.; Mildenberger, G.; Bekkers, R.H.F.P.; Brink Lund, A.

2014-01-01

This report brings together findings from the first ITSSOIN project working steps to formulate empirically testable hypotheses on the impact of the third sector and social innovation – in particular regarding the role of the third sector in generating social innovation but also with reference to

Testing hypotheses in order

OpenAIRE

Paul R. Rosenbaum

2008-01-01

In certain circumstances, one wishes to test one hypothesis only if certain other hypotheses have been rejected. This ordering of hypotheses simplifies the task of controlling the probability of rejecting any true hypothesis. In an example from an observational study, a treated group is shown to be further from both of two control groups than the two control groups are from each other. Copyright 2008, Oxford University Press.

Explanatory hypotheses formation and the anomalous β spectrum

Energy Technology Data Exchange (ETDEWEB)

Gauderis, Tjerk [Centre for Logic and Philosophy of Science, Ghent University (Belgium)

2013-07-01

Between 1928 and 1934, a persevering anomaly mystified the physics community: while alpha decay behaved perfectly according to the new quantum mechanics, the energy of electrons emitted in beta decay displayed a broad continuous spectrum. This puzzle invoked a lively debate among the most established physicists at the time. But the curious thing was that they all suggested hypotheses of very different formal types: Rutherford and Chadwick thought of varying internal energies, Bohr suggested to restrict the energy conservation principle, Heisenberg tinkered with a new quantization of space, and Pauli suggested the existence of a new elementary particle - all these hypotheses being radical and highly controversial. In physics, an anomalous experimental result can trigger the formation of formally very different hypotheses. A scientist confronted with such a result has no strict guidelines to help her decide whether she should explain this result by withdrawing or adapting a constraint (e.g. a law) of the current theory, or by presupposing the existence of a hitherto unobserved entity (e.g. a particle) that makes the anomaly fit within that theory. In this talk I aim to gain some insights how scientists make this choice, by examining in the above case study how the choice of the various mentioned physicists depended on their previous experiences and their specific perception of the problem.

Political market orientation and strategic party postures: Some hypotheses regarding profiles and relationship strengths

DEFF Research Database (Denmark)

Ormrod, Robert P.; Henneberg, Stephan C. M.

2007-01-01

an integrated construct of political marketing strategy which is exemplified by the derivation of hypotheses of the relationships between organizational stances on the one hand, and attitudinal and behavioural aspects of political market orientation on the other. We propose two levels of hypotheses: Firstly......Recently, the areas of strategic political marketing as well as political market orientation have been the subject of several conceptual articles (e.g., Henneberg 2006a; O'Cass 1996; Ormrod 2005, 2007). These have laid the theoretical foundations for further empirical work (e.g., Henneberg 2006b; O......'Cass 1996, 2001a, 2001b; Ormrod et al. 2007; Ormrod and Henneberg 2008 forthcoming). However, despite the close conceptual relatedness between some of these concepts they have yet to be integrated to provide a more nuanced picture which researchers but also political marketing practitioners can utilise...

How prayer heals: a theoretical model.

Science.gov (United States)

Levin, J S

1996-01-01

This article presents a theoretical model that outlines various possible explanations for the healing effects of prayer. Four classes of mechanisms are defined on the basis of whether healing has naturalistic or supernatural origins and whether it operates locally or nonlocally. Through this framework, most of the currently proposed hypotheses for understanding absent healing and other related phenomena-hypotheses that invoke such concepts as subtle energy, psi, consciousness, morphic fields, and extended mind-are shown to be no less naturalistic than the Newtonian, mechanistic forces of allopathic biomedicine so often derided for their materialism. In proposing that prayer may heal through nonlocal means according to mechanisms and theories proposed by the new physics, Dossey is almost alone among medical scholars in suggesting the possible limitations and inadequacies of hypotheses based on energies, forces, and fields. Yet even such nonlocal effects can be conceived of as naturalistic; that is, they are explained by physical laws that may be unbelievable or unfamiliar to most physicians but that are nonetheless becoming recognized as operant laws of the natural universe. The concept of the supernatural, however, is something altogether different, and is, by definition, outside of or beyond nature. Herein may reside an either wholly or partly transcendent Creator-God who is believed by many to heal through means that transcend the laws of the created universe, both its local and nonlocal elements, and that are thus inherently inaccessible to and unknowable by science. Such an explanation for the effects of prayer merits consideration and, despite its unprovability by medical science, should not be dismissed out of hand.

Theoretical explanations for maintenance of behaviour change: a systematic review of behaviour theories.

Science.gov (United States)

Kwasnicka, Dominika; Dombrowski, Stephan U; White, Martin; Sniehotta, Falko

2016-09-01

Behaviour change interventions are effective in supporting individuals in achieving temporary behaviour change. Behaviour change maintenance, however, is rarely attained. The aim of this review was to identify and synthesise current theoretical explanations for behaviour change maintenance to inform future research and practice. Potentially relevant theories were identified through systematic searches of electronic databases (Ovid MEDLINE, Embase, PsycINFO). In addition, an existing database of 80 theories was searched, and 25 theory experts were consulted. Theories were included if they formulated hypotheses about behaviour change maintenance. Included theories were synthesised thematically to ascertain overarching explanations for behaviour change maintenance. Initial theoretical themes were cross-validated. One hundred and seventeen behaviour theories were identified, of which 100 met the inclusion criteria. Five overarching, interconnected themes representing theoretical explanations for behaviour change maintenance emerged. Theoretical explanations of behaviour change maintenance focus on the differential nature and role of motives, self-regulation, resources (psychological and physical), habits, and environmental and social influences from initiation to maintenance. There are distinct patterns of theoretical explanations for behaviour change and for behaviour change maintenance. The findings from this review can guide the development and evaluation of interventions promoting maintenance of health behaviours and help in the development of an integrated theory of behaviour change maintenance.

Advancing the literature on designing audit and feedback interventions: identifying theory-informed hypotheses.

Science.gov (United States)

Colquhoun, Heather L; Carroll, Kelly; Eva, Kevin W; Grimshaw, Jeremy M; Ivers, Noah; Michie, Susan; Sales, Anne; Brehaut, Jamie C

2017-09-29

Audit and feedback (A&F) is a common strategy for helping health providers to implement evidence into practice. Despite being extensively studied, health care A&F interventions remain variably effective, with overall effect sizes that have not improved since 2003. Contributing to this stagnation is the fact that most health care A&F interventions have largely been designed without being informed by theoretical understanding from the behavioral and social sciences. To determine if the trend can be improved, the objective of this study was to develop a list of testable, theory-informed hypotheses about how to design more effective A&F interventions. Using purposive sampling, semi-structured 60-90-min telephone interviews were conducted with experts in theories related to A&F from a range of fields (e.g., cognitive, health and organizational psychology, medical decision-making, economics). Guided by detailed descriptions of A&F interventions from the health care literature, interviewees described how they would approach the problem of designing improved A&F interventions. Specific, theory-informed hypotheses about the conditions for effective design and delivery of A&F interventions were elicited from the interviews. The resulting hypotheses were assigned by three coders working independently into themes, and categories of themes, in an iterative process. We conducted 28 interviews and identified 313 theory-informed hypotheses, which were placed into 30 themes. The 30 themes included hypotheses related to the following five categories: A&F recipient (seven themes), content of the A&F (ten themes), process of delivery of the A&F (six themes), behavior that was the focus of the A&F (three themes), and other (four themes). We have identified a set of testable, theory-informed hypotheses from a broad range of behavioral and social science that suggest conditions for more effective A&F interventions. This work demonstrates the breadth of perspectives about A&F from non

Muon-neutrino-induced charged-current cross section without pions: Theoretical analysis

Science.gov (United States)

Mosel, U.; Gallmeister, K.

2018-04-01

We calculate the charged-current cross sections obtained at the T2K near detector for νμ-induced events without pions in the final state. The method used is quantum-kinetic transport theory. Results are shown first, as a benchmark, for electron-inclusive cross sections on 12C and 16O to be followed with a detailed comparison with the data measured by the T2K Collaboration on C8H8 and H2O targets. The contribution of 2p2h processes is found to be relevant mostly for backward angles; their theoretical uncertainties are within the experimental uncertainties. Particular emphasis is then put on a discussion of events in which pions are first created but then reabsorbed. Their contribution is found to be essential at forward angles.

Family stress and parental responses to children's negative emotions: tests of the spillover, crossover, and compensatory hypotheses.

Science.gov (United States)

Nelson, Jackie A; O'Brien, Marion; Blankson, A Nayena; Calkins, Susan D; Keane, Susan P

2009-10-01

The relations between 4 sources of family stress (marital dissatisfaction, home chaos, parental depressive symptoms, and job role dissatisfaction) and the emotion socialization practice of mothers' and fathers' responses to children's negative emotions were examined. Participants included 101 couples with 7-year-old children. Dyadic analyses were conducted using the Actor-Partner Interdependence Model and relations were tested in terms of the spillover, crossover, and compensatory hypotheses. Results suggest that measures of family stress relate to supportive and nonsupportive parental responses, though many of these relations differ by parent gender. The results are discussed in terms of the 3 theoretical hypotheses, all of which are supported to some degree depending on the family stressor examined.

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.

Economic and evolutionary hypotheses for cross-population variation in parochialism

OpenAIRE

Daniel Jacob Hruschka; Joseph eHenrich

2013-01-01

Human populations differ reliably in the degree to which people favor family, friends and community members over strangers and outsiders. In the last decade, researchers have begun to propose several economic and evolutionary hypotheses for these cross-population differences in parochialism. In this paper, we outline major current theories and review recent attempts to test them. We also discuss the key methodological challenges in assessing these diverse economic and evolutionary theories...

Conceptual representations in mind and brain: theoretical developments, current evidence and future directions.

Science.gov (United States)

Kiefer, Markus; Pulvermüller, Friedemann

2012-07-01

Conceptual representations in long-term memory crucially contribute to perception and action, language and thought. However, the precise nature of these conceptual memory traces is discussed controversially. In particular, the grounding of concepts in the sensory and motor brain systems is the focus of a current debate. Here, we review theoretical accounts of the structure and neural basis of conceptual memory and evaluate them in light of recent empirical evidence. Models of conceptual processing can be distinguished along four dimensions: (i) amodal versus modality-specific, (ii) localist versus distributed, (iii) innate versus experience-dependent, and (iv) stable versus flexible. A systematic review of behavioral and neuroimaging studies in healthy participants along with brain-damaged patients will then be used to evaluate the competing theoretical approaches to conceptual representations. These findings indicate that concepts are flexible, distributed representations comprised of modality-specific conceptual features. Conceptual features are stored in distinct sensory and motor brain areas depending on specific sensory and motor experiences during concept acquisition. Three important controversial issues are highlighted, which require further clarification in future research: the existence of an amodal conceptual representation in the anterior temporal lobe, the causal role of sensory and motor activation for conceptual processing and the grounding of abstract concepts in perception and action. We argue that an embodiment view of conceptual representations realized as distributed sensory and motor cell assemblies that are complemented by supramodal integration brain circuits may serve as a theoretical framework to guide future research on concrete and abstract concepts. Copyright © 2011 Elsevier Srl. All rights reserved.

Ergonomic project of the work and innovation in the virtual-actual dynamic: a theoretical-conceptual contribution

Directory of Open Access Journals (Sweden)

Gilbert Cardoso Bouyer

2015-12-01

Full Text Available The main purpose of this paper is to amplify the current theoretical scenario of “Ergonomics of Project” area, according to the knowledge creation/innovation theory, and his concepts of virtual and subjectivity in the Work. This theoretical-conceptual article aims to shed new light on the relations between innovation and present-day efforts toward a scientific theory of knowledge in the Work, with its complex structure of theories, hypotheses and disciplines. There is in this paper a new approach to understand  the Contemporary Ergonomic Project in a kind of Socio-Epistemological Engineering initiated by Markus F. Peschl in the University of Vienna. The methods employed were the systematic review and adaptation of Socio-Epistemological Engineering’s concepts in the actual context of epistemological and ontological principles of Ergonomics of Project.

Family Stress and Parental Responses to Children’s Negative Emotions: Tests of the Spillover, Crossover, and Compensatory Hypotheses

Science.gov (United States)

Nelson, Jackie A.; O’Brien, Marion; Blankson, A. Nayena; Calkins, Susan D.; Keane, Susan P.

2010-01-01

The relations between 4 sources of family stress (marital dissatisfaction, home chaos, parental depressive symptoms, and job role dissatisfaction) and the emotion socialization practice of mothers’ and fathers’ responses to children’s negative emotions were examined. Participants included 101 couples with 7-year-old children. Dyadic analyses were conducted using the Actor–Partner Interdependence Model and relations were tested in terms of the spillover, crossover, and compensatory hypotheses. Results suggest that measures of family stress relate to supportive and nonsupportive parental responses, though many of these relations differ by parent gender. The results are discussed in terms of the 3 theoretical hypotheses, all of which are supported to some degree depending on the family stressor examined. PMID:19803603

Theoretical explanations for maintenance of behaviour change: a systematic review of behaviour theories

Science.gov (United States)

Kwasnicka, Dominika; Dombrowski, Stephan U; White, Martin; Sniehotta, Falko

2016-01-01

ABSTRACT Background: Behaviour change interventions are effective in supporting individuals in achieving temporary behaviour change. Behaviour change maintenance, however, is rarely attained. The aim of this review was to identify and synthesise current theoretical explanations for behaviour change maintenance to inform future research and practice. Methods: Potentially relevant theories were identified through systematic searches of electronic databases (Ovid MEDLINE, Embase, PsycINFO). In addition, an existing database of 80 theories was searched, and 25 theory experts were consulted. Theories were included if they formulated hypotheses about behaviour change maintenance. Included theories were synthesised thematically to ascertain overarching explanations for behaviour change maintenance. Initial theoretical themes were cross-validated. Findings: One hundred and seventeen behaviour theories were identified, of which 100 met the inclusion criteria. Five overarching, interconnected themes representing theoretical explanations for behaviour change maintenance emerged. Theoretical explanations of behaviour change maintenance focus on the differential nature and role of motives, self-regulation, resources (psychological and physical), habits, and environmental and social influences from initiation to maintenance. Discussion: There are distinct patterns of theoretical explanations for behaviour change and for behaviour change maintenance. The findings from this review can guide the development and evaluation of interventions promoting maintenance of health behaviours and help in the development of an integrated theory of behaviour change maintenance. PMID:26854092

Theoretical and practical program in the non-destructive testing by eddy currents - the first level

International Nuclear Information System (INIS)

Shaaban, H.I.; Addarwish, J.M.A.

2014-11-01

The testing using eddy currents is one of the non-destructive tests that use electromagnetic property as a basis for testing procedures, and there are many other ways to use this principle, including Remote Field Testing and the Magnetic Flux Leakage test. Eddy currents are electrical currents moving in a circular path, and took the name eddy of eddies that form when a liquid or gas is moving in a circular path because of objection obstacles to its track. They are generated in the material using a variable magnetic field. Non-destructive testing by eddy currents is a technique used for the detection of defects and interruptions in a material and it is a process that relies on the generation of small eddy currents in the material of the part to be examined, provided that this part is of an electrically conducting material. This technique and its scientific basis are explained in this book. Also the devices used in this technique and how to use these devices in details are explained. The book contains Twelve chapters: Introduction to non destructive testing - Engineering materials and its mechanical characteristics - Electrical and magnetic characteristics of engineering materials - Introduction to testing by eddy currents - Factors affecting eddy currents - Basis of electrical circuits used in eddy currents testing devices - Probes of eddy currents testing - Eddy currents testing devices (Theoretical) - Analysis of the examination results of testing by eddy currents: techniques and applications - Applications of testing by eddy currents - Eddy currents testing devices (Application) - Practical lessons for the first level in testing by eddy currents.

Evaluation of Extremal Hypotheses as a Criterion to Resolve Channel Indeterminacy

Science.gov (United States)

Tranmer, A.

2012-12-01

Design criteria for river restoration and sustainable development have significantly advanced in recent decades, yet complete deterministic formulations to address channel form and sinuosity still prove elusive. Many hypotheses have been presented to ascertain the dynamic-equilibrium of a stream at both the cross sectional and reach level. These efforts to better understand the functioning of alluvial systems include regime theory, stability theory, perturbation analysis, threshold theory, reference reach comparison, downstream hydraulic geometry, and extremal hypotheses. The latter of these theories, the extremal hypothesis, is based on optimizing one variable or criterion in the alluvial system in order to find closure to the channel design problem. Currently, there is no method to directly compare the various hypotheses at the system scale, understanding of their sensitivity to the various formulae employed or consensus regarding which hypothesis is most appropriate. This study analyzed the various extremal hypotheses in as close to a pristine environment as exists (a remote part of Patagonia, Chile), in order to assess which hypothesis (or collective hypotheses) is most appropriate for channel design. Extremal hypotheses were applied in the longitudinal direction, under the assumption of a space-for-time substitution, to evaluate the geomorphic trends of a river evolving during deglaciation. The space-for-time model assumes the watershed reaches stable, dynamic-equilibrium in its lower meandering reaches and the point of equilibrium extends upstream through its braiding reaches as the watershed adapts to new climatic and environmental conditions. Extremal hypotheses applied in a downstream fashion are then expected to predict chaotic and oversized channel characteristics in the upstream reaches and trend towards a point of equilibrium (minimum/maximum of tested hypothesis). Initial findings indicate that many hypotheses predict similar geometry and sinuosity

Economic and evolutionary hypotheses for cross-population variation in parochialism.

Science.gov (United States)

Hruschka, Daniel J; Henrich, Joseph

2013-09-11

Human populations differ reliably in the degree to which people favor family, friends, and community members over strangers and outsiders. In the last decade, researchers have begun to propose several economic and evolutionary hypotheses for these cross-population differences in parochialism. In this paper, we outline major current theories and review recent attempts to test them. We also discuss the key methodological challenges in assessing these diverse economic and evolutionary theories for cross-population differences in parochialism.

Predictive hypotheses are ineffectual in resolving complex biochemical systems.

Science.gov (United States)

Fry, Michael

2018-03-20

Scientific hypotheses may either predict particular unknown facts or accommodate previously-known data. Although affirmed predictions are intuitively more rewarding than accommodations of established facts, opinions divide whether predictive hypotheses are also epistemically superior to accommodation hypotheses. This paper examines the contribution of predictive hypotheses to discoveries of several bio-molecular systems. Having all the necessary elements of the system known beforehand, an abstract predictive hypothesis of semiconservative mode of DNA replication was successfully affirmed. However, in defining the genetic code whose biochemical basis was unclear, hypotheses were only partially effective and supplementary experimentation was required for its conclusive definition. Markedly, hypotheses were entirely inept in predicting workings of complex systems that included unknown elements. Thus, hypotheses did not predict the existence and function of mRNA, the multiple unidentified components of the protein biosynthesis machinery, or the manifold unknown constituents of the ubiquitin-proteasome system of protein breakdown. Consequently, because of their inability to envision unknown entities, predictive hypotheses did not contribute to the elucidation of cation theories remained the sole instrument to explain complex bio-molecular systems, the philosophical question of alleged advantage of predictive over accommodative hypotheses became inconsequential.

Theoretical study of electronic transfer current rate at dye-sensitized solar cells

Science.gov (United States)

AL-Agealy, Hadi J. M.; AlMaadhede, Taif Saad; Hassooni, Mohsin A.; Sadoon, Abbas K.; Ashweik, Ahmed M.; Mahdi, Hind Abdlmajeed; Ghadhban, Rawnaq Qays

2018-05-01

In this research, we present a theoretical study of electronic transfer kinetics rate in N719/TiO2 and N719/ZnO dye-sensitized solar cells (DSSC) systems using a simple model depending on the postulate of quantum mechanics theory. The evaluation of the electronic transition current rate in DSSC systems are function of many parameters such that; the reorientation transition energies ΛSe m D y e , the transition coupling parameter ℂT(0), potential exponential effect e-(E/C-EF ) kBT , unit cell volume VSem, and temperature T. Furthermore, the analysis of electronic transfer current rate in N719/TiO2 and N719/ZnO systems show that the rate upon dye-sensitization solar cell increases with increases of transition coupling parameter, decreasing potential that building at interface a results of different material in this devices and increasing with reorientation transition energy. On the other hand, we can find the electronic transfer behavior is dependent of the dye absorption spectrum and mainly depending on the reorientation of transition energy. The replacement of the solvents in both DSSC system caused increasing of current rates dramatically depending on polarity of solvent in subset devices. This change in current rate of electron transfer were attributed to much more available of recombination sites introduced by the solvents medium. The electronic transfer current dynamics are shown to occurs in N719/TiO2 system faster many time compare to ocuures at N719/ZnO system, this indicate that TiO2 a is a good and active material compare with ZnO to using in dye sensitized solar cell devices. In contrast, the large current rate in N719/TiO2 comparing to ZnO of N719/ZnO systems indicate that using TiO2 with N719 dye lead to increasing the efficiency of DSSC.

Economic and evolutionary hypotheses for cross-population variation in parochialism

Directory of Open Access Journals (Sweden)

Daniel Jacob Hruschka

2013-09-01

Full Text Available Human populations differ reliably in the degree to which people favor family, friends and community members over strangers and outsiders. In the last decade, researchers have begun to propose several economic and evolutionary hypotheses for these cross-population differences in parochialism. In this paper, we outline major current theories and review recent attempts to test them. We also discuss the key methodological challenges in assessing these diverse economic and evolutionary theories for cross-population differences in parochialism.

Quantitative linking hypotheses for infant eye movements.

Directory of Open Access Journals (Sweden)

Daniel Yurovsky

Full Text Available The study of cognitive development hinges, largely, on the analysis of infant looking. But analyses of eye gaze data require the adoption of linking hypotheses: assumptions about the relationship between observed eye movements and underlying cognitive processes. We develop a general framework for constructing, testing, and comparing these hypotheses, and thus for producing new insights into early cognitive development. We first introduce the general framework--applicable to any infant gaze experiment--and then demonstrate its utility by analyzing data from a set of experiments investigating the role of attentional cues in infant learning. The new analysis uncovers significantly more structure in these data, finding evidence of learning that was not found in standard analyses and showing an unexpected relationship between cue use and learning rate. Finally, we discuss general implications for the construction and testing of quantitative linking hypotheses. MATLAB code for sample linking hypotheses can be found on the first author's website.

Pearce element ratios: A paradigm for testing hypotheses

Science.gov (United States)

Russell, J. K.; Nicholls, Jim; Stanley, Clifford R.; Pearce, T. H.

Science moves forward with the development of new ideas that are encapsulated by hypotheses whose aim is to explain the structure of data sets or to expand existing theory. These hypotheses remain conjecture until they have been tested. In fact, Karl Popper advocated that a scientist's job does not finish with the creation of an idea but, rather, begins with the testing of the related hypotheses. In Popper's [1959] advocation it is implicit that there be tools with which we can test our hypotheses. Consequently, the development of rigorous tests for conceptual models plays a major role in maintaining the integrity of scientific endeavor [e.g., Greenwood, 1989].

Drug-Resistant Epilepsy: Multiple Hypotheses, Few Answers

Directory of Open Access Journals (Sweden)

Fei Tang

2017-07-01

Full Text Available Epilepsy is a common neurological disorder that affects over 70 million people worldwide. Despite the recent introduction of new antiseizure drugs (ASDs, about one-third of patients with epilepsy have seizures refractory to pharmacotherapy. Early identification of patients who will become refractory to ASDs could help direct such patients to appropriate non-pharmacological treatment, but the complexity in the temporal patterns of epilepsy could make such identification difficult. The target hypothesis and transporter hypothesis are the most cited theories trying to explain refractory epilepsy, but neither theory alone fully explains the neurobiological basis of pharmacoresistance. This review summarizes evidence for and against several major theories, including the pharmacokinetic hypothesis, neural network hypothesis, intrinsic severity hypothesis, gene variant hypothesis, target hypothesis, and transporter hypothesis. The discussion is mainly focused on the transporter hypothesis, where clinical and experimental data are discussed on multidrug transporter overexpression, substrate profiles of ASDs, mechanism of transporter upregulation, polymorphisms of transporters, and the use of transporter inhibitors. Finally, future perspectives are presented for the improvement of current hypotheses and the development of treatment strategies as guided by the current understanding of refractory epilepsy.

Developing a theoretical framework for complex community-based interventions.

Science.gov (United States)

Angeles, Ricardo N; Dolovich, Lisa; Kaczorowski, Janusz; Thabane, Lehana

2014-01-01

Applying existing theories to research, in the form of a theoretical framework, is necessary to advance knowledge from what is already known toward the next steps to be taken. This article proposes a guide on how to develop a theoretical framework for complex community-based interventions using the Cardiovascular Health Awareness Program as an example. Developing a theoretical framework starts with identifying the intervention's essential elements. Subsequent steps include the following: (a) identifying and defining the different variables (independent, dependent, mediating/intervening, moderating, and control); (b) postulating mechanisms how the independent variables will lead to the dependent variables; (c) identifying existing theoretical models supporting the theoretical framework under development; (d) scripting the theoretical framework into a figure or sets of statements as a series of hypotheses, if/then logic statements, or a visual model; (e) content and face validation of the theoretical framework; and (f) revising the theoretical framework. In our example, we combined the "diffusion of innovation theory" and the "health belief model" to develop our framework. Using the Cardiovascular Health Awareness Program as the model, we demonstrated a stepwise process of developing a theoretical framework. The challenges encountered are described, and an overview of the strategies employed to overcome these challenges is presented.

A survey of etiologic hypotheses among testicular cancer researchers.

Science.gov (United States)

Stang, A; Trabert, B; Rusner, C; Poole, C; Almstrup, K; Rajpert-De Meyts, E; McGlynn, K A

2015-01-01

Basic research results can provide new ideas and hypotheses to be examined in epidemiological studies. We conducted a survey among testicular cancer researchers on hypotheses concerning the etiology of this malignancy. All researchers on the mailing list of Copenhagen Testis Cancer Workshops and corresponding authors of PubMed-indexed articles identified by the search term 'testicular cancer' and published within 10 years (in total 2750 recipients) were invited to respond to an e-mail-based survey. Participants of the 8th Copenhagen Testis Cancer Workshop in May 2014 were subsequently asked to rate the plausibility of the suggested etiologic hypotheses on a scale of 1 (very implausible) to 10 (very plausible). This report describes the methodology of the survey, the score distributions by individual hypotheses, hypothesis group, and the participants' major research fields, and discuss the hypotheses that scored as most plausible. We also present plans for improving the survey that may be repeated at a next international meeting of experts in testicular cancer. Overall 52 of 99 (53%) registered participants of the 8th Copenhagen Testis Cancer Workshop submitted the plausibility rating form. Fourteen of 27 hypotheses were related to exposures during pregnancy. Hypotheses with the highest mean plausibility ratings were either related to pre-natal exposures or exposures that might have an effect during pregnancy and in post-natal life. The results of the survey may be helpful for triggering more specific etiologic hypotheses that include factors related to endocrine disruption, DNA damage, inflammation, and nutrition during pregnancy. The survey results may stimulate a multidisciplinary discussion about new etiologic hypotheses of testicular cancer. Published 2014. This article is a U. S. Government work and is in the public domain in the USA.

Testing competing hypotheses about single trial fMRI

DEFF Research Database (Denmark)

Hansen, Lars Kai; Purushotham, Archana; Kim, Seong-Ge

2002-01-01

We use a Bayesian framework to compute probabilities of competing hypotheses about functional activation based on single trial fMRI measurements. Within the framework we obtain a complete probabilistic picture of competing hypotheses, hence control of both type I and type II errors....

Scientific 'Laws', 'Hypotheses' and 'Theories'

Indian Academy of Sciences (India)

verified, the hypothesis changes from the status of a 'mere' hypothesis, and ... a pre-existing law and the body of facts upon which that law is based. Hypotheses .... implicit belief that order objectively exists in nature, and that scientific laws ...

Scientific 'Laws', 'Hypotheses' and 'Theories'

Indian Academy of Sciences (India)

theories, defines a hypothesis as "any supposition which we may ... about the origin of the solar system are also hypotheses of this type. They are about the birth of the planets, an event, which has happened, in the past history of our Universe.

Scientific'Laws','Hypotheses' and'Theories'

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 12. Scientific 'Laws', 'Hypotheses' and 'Theories' - How are They Related? J R Lakshmana Rao. General Article Volume 3 Issue 12 December 1998 pp 55-61. Fulltext. Click here to view fulltext PDF. Permanent link:

Testing hypotheses for differences between linear regression lines

Science.gov (United States)

Stanley J. Zarnoch

2009-01-01

Five hypotheses are identified for testing differences between simple linear regression lines. The distinctions between these hypotheses are based on a priori assumptions and illustrated with full and reduced models. The contrast approach is presented as an easy and complete method for testing for overall differences between the regressions and for making pairwise...

Independence of long-term contextual memory and short-term perceptual hypotheses: evidence from contextual cueing of interrupted search

OpenAIRE

Schlagbauer, B.; Mink, M.; Muller, Hermann J.; Geyer, T.

2017-01-01

Observers are able to resume an interrupted search trial faster relative to responding to a new, unseen display. This finding of rapid resumption is attributed to short-term perceptual hypotheses generated on the current look and confirmed upon subsequent looks at the same display. It has been suggested that the contents of perceptual hypotheses are similar to those of other forms of memory acquired long-term through repeated exposure to the same search displays over the course of several tri...

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.

Mechanistic Mathematical Modeling Tests Hypotheses of the Neurovascular Coupling in fMRI.

Directory of Open Access Journals (Sweden)

Karin Lundengård

2016-06-01

Full Text Available Functional magnetic resonance imaging (fMRI measures brain activity by detecting the blood-oxygen-level dependent (BOLD response to neural activity. The BOLD response depends on the neurovascular coupling, which connects cerebral blood flow, cerebral blood volume, and deoxyhemoglobin level to neuronal activity. The exact mechanisms behind this neurovascular coupling are not yet fully investigated. There are at least three different ways in which these mechanisms are being discussed. Firstly, mathematical models involving the so-called Balloon model describes the relation between oxygen metabolism, cerebral blood volume, and cerebral blood flow. However, the Balloon model does not describe cellular and biochemical mechanisms. Secondly, the metabolic feedback hypothesis, which is based on experimental findings on metabolism associated with brain activation, and thirdly, the neurotransmitter feed-forward hypothesis which describes intracellular pathways leading to vasoactive substance release. Both the metabolic feedback and the neurotransmitter feed-forward hypotheses have been extensively studied, but only experimentally. These two hypotheses have never been implemented as mathematical models. Here we investigate these two hypotheses by mechanistic mathematical modeling using a systems biology approach; these methods have been used in biological research for many years but never been applied to the BOLD response in fMRI. In the current work, model structures describing the metabolic feedback and the neurotransmitter feed-forward hypotheses were applied to measured BOLD responses in the visual cortex of 12 healthy volunteers. Evaluating each hypothesis separately shows that neither hypothesis alone can describe the data in a biologically plausible way. However, by adding metabolism to the neurotransmitter feed-forward model structure, we obtained a new model structure which is able to fit the estimation data and successfully predict new

The current status of theoretically based approaches to the prediction of the critical heat flux in flow boiling

International Nuclear Information System (INIS)

Weisman, J.

1991-01-01

This paper reports on the phenomena governing the critical heat flux in flow boiling. Inducts which vary with the flow pattern. Separate models are needed for dryout in annular flow, wall overheating in plug or slug flow and formation of a vapor blanket in dispersed flow. The major theories and their current status are described for the annular and dispersed regions. The need for development of the theoretical approach in the plug and slug flow region is indicated

Independence of long-term contextual memory and short-term perceptual hypotheses: Evidence from contextual cueing of interrupted search.

Science.gov (United States)

Schlagbauer, Bernhard; Mink, Maurice; Müller, Hermann J; Geyer, Thomas

2017-02-01

Observers are able to resume an interrupted search trial faster relative to responding to a new, unseen display. This finding of rapid resumption is attributed to short-term perceptual hypotheses generated on the current look and confirmed upon subsequent looks at the same display. It has been suggested that the contents of perceptual hypotheses are similar to those of other forms of memory acquired long-term through repeated exposure to the same search displays over the course of several trials, that is, the memory supporting "contextual cueing." In three experiments, we investigated the relationship between short-term perceptual hypotheses and long-term contextual memory. The results indicated that long-term, contextual memory of repeated displays neither affected the generation nor the confirmation of short-term perceptual hypotheses for these displays. Furthermore, the analysis of eye movements suggests that long-term memory provides an initial benefit in guiding attention to the target, whereas in subsequent looks guidance is entirely based on short-term perceptual hypotheses. Overall, the results reveal a picture of both long- and short-term memory contributing to reliable performance gains in interrupted search, while exerting their effects in an independent manner.

In silico generation of alternative hypotheses using causal mapping (CMAP.

Directory of Open Access Journals (Sweden)

Gabriel E Weinreb

Full Text Available Previously, we introduced causal mapping (CMAP as an easy to use systems biology tool for studying the behavior of biological processes that occur at the cellular and molecular level. CMAP is a coarse-grained graphical modeling approach in which the system of interest is modeled as an interaction map between functional elements of the system, in a manner similar to portrayals of signaling pathways commonly used by molecular cell biologists. CMAP describes details of the interactions while maintaining the simplicity of other qualitative methods (e.g., Boolean networks.In this paper, we use the CMAP methodology as a tool for generating hypotheses about the mechanisms that regulate molecular and cellular systems. Furthermore, our approach allows competing hypotheses to be ranked according to a fitness index and suggests experimental tests to distinguish competing high fitness hypotheses. To motivate the CMAP as a hypotheses generating tool and demonstrate the methodology, we first apply this protocol to a simple test-case of a three-element signaling module. Our methods are next applied to the more complex phenomenon of cortical oscillations observed in spreading cells. This analysis produces two high fitness hypotheses for the mechanism that underlies this dynamic behavior and suggests experiments to distinguish the hypotheses. The method can be widely applied to other cellular systems to generate and compare alternative hypotheses based on experimentally observed data and using computer simulations.

Human female orgasm as evolved signal: a test of two hypotheses.

Science.gov (United States)

Ellsworth, Ryan M; Bailey, Drew H

2013-11-01

We present the results of a study designed to empirically test predictions derived from two hypotheses regarding human female orgasm behavior as an evolved communicative trait or signal. One hypothesis tested was the female fidelity hypothesis, which posits that human female orgasm signals a woman's sexual satisfaction and therefore her likelihood of future fidelity to a partner. The other was sire choice hypothesis, which posits that women's orgasm behavior signals increased chances of fertilization. To test the two hypotheses of human female orgasm, we administered a questionnaire to 138 females and 121 males who reported that they were currently in a romantic relationship. Key predictions of the female fidelity hypothesis were not supported. In particular, orgasm was not associated with female sexual fidelity nor was orgasm associated with male perceptions of partner sexual fidelity. However, faked orgasm was associated with female sexual infidelity and lower male relationship satisfaction. Overall, results were in greater support of the sire choice signaling hypothesis than the female fidelity hypothesis. Results also suggest that male satisfaction with, investment in, and sexual fidelity to a mate are benefits that favored the selection of orgasmic signaling in ancestral females.

Seed dormancy and germination - Emerging mechanisms and new hypotheses

Directory of Open Access Journals (Sweden)

Hiroyuki eNonogaki

2014-05-01

Full Text Available Seed dormancy has played a significant role in adaptation and evolution of seed plants. While its biological significance is clear, molecular mechanisms underlying seed dormancy induction, maintenance and alleviation still remain elusive. Intensive efforts have been made to investigate gibberellin and abscisic acid metabolism in seeds, which greatly contributed to the current understanding of seed dormancy mechanisms. Other mechanisms, which might be independent of hormones, or specific to the seed dormancy pathway, are also emerging from genetic analysis of seed dormancy mutants. These studies suggest that chromatin remodeling through histone ubiquitination, methylation and acetylation, which could lead to transcription elongation or gene silencing, may play a significant role in seed dormancy regulation. Small interfering RNA and/or long non-coding RNA might be a trigger of epigenetic changes at the seed dormancy or germination loci, such as DELAY OF GERMINATION1. While new mechanisms are emerging from genetic studies of seed dormancy, novel hypotheses are also generated from seed germination study with high throughput gene expression analysis. Recent studies on tissue-specific gene expression in tomato and Arabidopsis seeds, which suggested possible mechanosensing in the regulatory mechanisms, advanced our understanding of embryo-endosperm interaction and have potential to re-draw the traditional hypotheses or integrate them into a comprehensive scheme. The progress in basic seed science will enable knowledge translation, another frontier of research to be expanded for food and fuel production.

Theoretical physics division

International Nuclear Information System (INIS)

Anon.

The studies in 1977 are reviewed. In theoretical nuclear physics: nuclear structure, nuclear reactions, intermediate energy physics; in elementary particle physics: field theory, strong interactions dynamics, nucleon-nucleon interactions, new particles, current algebra, symmetries and quarks are studied [fr

New hypotheses regarding the Danish health puzzle.

Science.gov (United States)

Bakah, May; Raphael, Dennis

2017-12-01

Nordic welfare states have achieved admirable population health profiles as a result of public policies that provide economic and social security across the life course. Denmark has been an exception to this rule, as its life expectancies and infant mortality rates since the mid-1970s have lagged behind the other Nordic nations and, in the case of life expectancy, behind most Organisation for Economic Co-operation and Development nations. In this review paper, we identify a number of new hypotheses for why this may be the case. These hypotheses concern the health effects of neo-liberal restructuring of the economy and its institutions, the institution of flexi-security in Denmark's labour market and the influence of Denmark's tobacco and alcohol industries. Also of note is that Denmark experienced higher unemployment rates during its initial period of health stagnation, as well as its treatment of non-Western immigrants and high wealth inequality and, until recently, the fact that Denmark did not systematically address the issue of health inequalities. These hypotheses may serve as covering explanations for the usually provided accounts of elevated behavioural risks and psychosocial stress as being responsible for Denmark's health profile.

Theoretical behaviorism meets embodied cognition : Two theoretical analyses of behavior

NARCIS (Netherlands)

Keijzer, F.A.

2005-01-01

This paper aims to do three things: First, to provide a review of John Staddon's book Adaptive dynamics: The theoretical analysis of behavior. Second, to compare Staddon's behaviorist view with current ideas on embodied cognition. Third, to use this comparison to explicate some outlines for a

The revelation effect: A meta-analytic test of hypotheses.

Science.gov (United States)

Aßfalg, André; Bernstein, Daniel M; Hockley, William

2017-12-01

Judgments can depend on the activity directly preceding them. An example is the revelation effect whereby participants are more likely to claim that a stimulus is familiar after a preceding task, such as solving an anagram, than without a preceding task. We test conflicting predictions of four revelation-effect hypotheses in a meta-analysis of 26 years of revelation-effect research. The hypotheses' predictions refer to three subject areas: (1) the basis of judgments that are subject to the revelation effect (recollection vs. familiarity vs. fluency), (2) the degree of similarity between the task and test item, and (3) the difficulty of the preceding task. We use a hierarchical multivariate meta-analysis to account for dependent effect sizes and variance in experimental procedures. We test the revelation-effect hypotheses with a model selection procedure, where each model corresponds to a prediction of a revelation-effect hypothesis. We further quantify the amount of evidence for one model compared to another with Bayes factors. The results of this analysis suggest that none of the extant revelation-effect hypotheses can fully account for the data. The general vagueness of revelation-effect hypotheses and the scarcity of data were the major limiting factors in our analyses, emphasizing the need for formalized theories and further research into the puzzling revelation effect.

Theoretical Foundations of the Relations betweenControlling and Reporting according to IFRSDemonstrated by the Example of Segment Reporting according to IFRS 8

Directory of Open Access Journals (Sweden)

Marcell Schweitzer

2009-11-01

Full Text Available In this paper, the unilateral and reciprocal impact of transfer relations between controlling and reporting according to IFRS is analysed, using the example of internal and external segment reporting. In contrast to the pragmatic treatment of this problem by the International Accounting Standards Board (IASB, the transfer relations are examined in this paper on a theoretically substantiated basis. For this purpose, transfer hypotheses are formulated as general statements on the determinants and effects of reporting. They form the elements of a reporting theory. The analysis focuses on the full management approach, which has a number of effects for the transfer relation between internal and external segment reporting. In detail, on the basis of transfer hypotheses, the effects for controlling, for the structure of segment reporting, and for the auditing of segment reporting are presented and analysed. As the IFRS do not constitute a settled system of rules, open questions as to such a body of rules are also discussed. In doing so – also on the basis of transfer hypotheses – alternatives of the improvement of segment reporting are analysed. This is done with the aid of reliability hypotheses, valuation hypotheses, simplification hypotheses, steering hypotheses and addressees hypotheses. In this way, the theoretical substantiation of the transfer relations between controlling and reporting according to IFRS is scientifically established, both for the present structure of accounting and for future design alternatives.

Singularity hypotheses a scientific and philosophical assessment

CERN Document Server

Moor, James; Søraker, Johnny; Steinhart, Eric

2012-01-01

Singularity Hypotheses: A Scientific and Philosophical Assessment offers authoritative, jargon-free essays and critical commentaries on accelerating technological progress and the notion of technological singularity. It focuses on conjectures about the intelligence explosion, transhumanism, and whole brain emulation. Recent years have seen a plethora of forecasts about the profound, disruptive impact that is likely to result from further progress in these areas. Many commentators however doubt the scientific rigor of these forecasts, rejecting them as speculative and unfounded. We therefore invited prominent computer scientists, physicists, philosophers, biologists, economists and other thinkers to assess the singularity hypotheses. Their contributions go beyond speculation, providing deep insights into the main issues and a balanced picture of the debate.

Empathy Is a Protective Factor of Burnout in Physicians: New Neuro-Phenomenological Hypotheses Regarding Empathy and Sympathy in Care Relationship.

Science.gov (United States)

Thirioux, Bérangère; Birault, François; Jaafari, Nematollah

2016-01-01

Burnout is a multidimensional work-related syndrome that is characterized by emotional exhaustion, depersonalization-or cynicism-and diminution of personal accomplishment. Burnout particularly affects physicians. In medicine as well as other professions, burnout occurrence depends on personal, developmental-psychodynamic, professional, and environmental factors. Recently, it has been proposed to specifically define burnout in physicians as "pathology of care relationship." That is, burnout would arise, among the above-mentioned factors, from the specificity of the care relationship as it develops between the physician and the patient. Accordingly, experimental studies and theoretical approaches have suggested that burnout and empathy, which is one of the most important skills in physicians, are closely linked. However, the nature of the relation between burnout and empathy remains not yet understood, as reflected in the variety of theoretical and contradictory hypotheses attempting to causally relate these two phenomena. Firstly, we here question the epistemological problem concerning the modality of the burnout-empathy link. Secondly, we hypothesize that considering the multidimensional features of both burnout and empathy, on one hand, and on the other hand, the distinction between empathy and sympathy enables to overcome these contradictions and, consequently, gives a better understanding of the relationship between burnout and empathy in physicians. Thirdly, we propose that clarifying the link between burnout, empathy and sympathy would enable developing specific training in medical students and continuous professional formation in senior physicians and would potentially contribute to the prevention of burnout in medical care.

Empathy is a protective factor of burnout in physicians: new neuro-phenomenological hypotheses regarding empathy and sympathy in care relationship

Directory of Open Access Journals (Sweden)

Berangere eTHIRIOUX

2016-05-01

Full Text Available Burnout is a multidimensional work-related syndrome that is characterized by emotional exhaustion, depersonalization – or cynicism – and diminution of personal accomplishment. Burnout particularly affects physicians. In medicine as well as other professions, burnout occurrence depends on personal, developmental-psychodynamic, professional and environmental factors. Recently, it has been proposed to specifically define burnout in physicians as pathology of care relationship. That is, burnout would arise, among the above-mentioned factors, from the specificity of the care relationship as it develops between the physician and the patient. Accordingly, experimental studies and theoretical approaches have suggested that burnout and empathy, which is one of the most important skills in physicians, are closely linked. However, the nature of the relation between burnout and empathy remains not yet understood, as reflected in the variety of theoretical and contradictory hypotheses attempting to causally relate these two phenomena. Firstly, we here question the epistemological problem concerning the modality of the burnout-empathy link. Secondly, we hypothesize that considering the multidimensional features of both burnout and empathy, on one hand, and on the other hand, the distinction between empathy and sympathy enables to overcome these contradictions and, consequently, gives a better understanding of the relationship between burnout and empathy in physicians. Thirdly, we propose that clarifying the link between burnout, empathy and sympathy would enable developing specific training in medical students and continuous professional formation in senior physicians and would potentially contribute to the prevention of burnout in medical care.

Empathy Is a Protective Factor of Burnout in Physicians: New Neuro-Phenomenological Hypotheses Regarding Empathy and Sympathy in Care Relationship

Science.gov (United States)

Thirioux, Bérangère; Birault, François; Jaafari, Nematollah

2016-01-01

Burnout is a multidimensional work-related syndrome that is characterized by emotional exhaustion, depersonalization—or cynicism—and diminution of personal accomplishment. Burnout particularly affects physicians. In medicine as well as other professions, burnout occurrence depends on personal, developmental-psychodynamic, professional, and environmental factors. Recently, it has been proposed to specifically define burnout in physicians as “pathology of care relationship.” That is, burnout would arise, among the above-mentioned factors, from the specificity of the care relationship as it develops between the physician and the patient. Accordingly, experimental studies and theoretical approaches have suggested that burnout and empathy, which is one of the most important skills in physicians, are closely linked. However, the nature of the relation between burnout and empathy remains not yet understood, as reflected in the variety of theoretical and contradictory hypotheses attempting to causally relate these two phenomena. Firstly, we here question the epistemological problem concerning the modality of the burnout-empathy link. Secondly, we hypothesize that considering the multidimensional features of both burnout and empathy, on one hand, and on the other hand, the distinction between empathy and sympathy enables to overcome these contradictions and, consequently, gives a better understanding of the relationship between burnout and empathy in physicians. Thirdly, we propose that clarifying the link between burnout, empathy and sympathy would enable developing specific training in medical students and continuous professional formation in senior physicians and would potentially contribute to the prevention of burnout in medical care. PMID:27303328

Organizational culture and organizational effectiveness: a meta-analytic investigation of the competing values framework's theoretical suppositions.

Science.gov (United States)

Hartnell, Chad A; Ou, Amy Yi; Kinicki, Angelo

2011-07-01

We apply Quinn and Rohrbaugh's (1983) competing values framework (CVF) as an organizing taxonomy to meta-analytically test hypotheses about the relationship between 3 culture types and 3 major indices of organizational effectiveness (employee attitudes, operational performance [i.e., innovation and product and service quality], and financial performance). The paper also tests theoretical suppositions undergirding the CVF by investigating the framework's nomological validity and proposed internal structure (i.e., interrelationships among culture types). Results based on data from 84 empirical studies with 94 independent samples indicate that clan, adhocracy, and market cultures are differentially and positively associated with the effectiveness criteria, though not always as hypothesized. The findings provide mixed support for the CVF's nomological validity and fail to support aspects of the CVF's proposed internal structure. We propose an alternative theoretical approach to the CVF and delineate directions for future research.

Emotional Intelligence: A Theoretical Framework for Individual Differences in Affective Forecasting

Science.gov (United States)

Hoerger, Michael; Chapman, Benjamin P.; Epstein, Ronald M.; Duberstein, Paul R.

2011-01-01

Only recently have researchers begun to examine individual differences in affective forecasting. The present investigation was designed to make a theoretical contribution to this emerging literature by examining the role of emotional intelligence in affective forecasting. Emotional intelligence was hypothesized to be associated with affective forecasting accuracy, memory for emotional reactions, and subsequent improvement on an affective forecasting task involving emotionally-evocative pictures. Results from two studies (N = 511) supported our hypotheses. Emotional intelligence was associated with accuracy in predicting, encoding, and consolidating emotional reactions. Furthermore, emotional intelligence was associated with greater improvement on a second affective forecasting task, with the relationship explained by basic memory processes. Implications for future research on basic and applied decision making are discussed. PMID:22251053

Testing Adaptive Hypotheses of Convergence with Functional Landscapes: A Case Study of Bone-Cracking Hypercarnivores

Science.gov (United States)

Tseng, Zhijie Jack

2013-01-01

Morphological convergence is a well documented phenomenon in mammals, and adaptive explanations are commonly employed to infer similar functions for convergent characteristics. I present a study that adopts aspects of theoretical morphology and engineering optimization to test hypotheses about adaptive convergent evolution. Bone-cracking ecomorphologies in Carnivora were used as a case study. Previous research has shown that skull deepening and widening are major evolutionary patterns in convergent bone-cracking canids and hyaenids. A simple two-dimensional design space, with skull width-to-length and depth-to-length ratios as variables, was used to examine optimized shapes for two functional properties: mechanical advantage (MA) and strain energy (SE). Functionality of theoretical skull shapes was studied using finite element analysis (FEA) and visualized as functional landscapes. The distribution of actual skull shapes in the landscape showed a convergent trend of plesiomorphically low-MA and moderate-SE skulls evolving towards higher-MA and moderate-SE skulls; this is corroborated by FEA of 13 actual specimens. Nevertheless, regions exist in the landscape where high-MA and lower-SE shapes are not represented by existing species; their vacancy is observed even at higher taxonomic levels. Results highlight the interaction of biomechanical and non-biomechanical factors in constraining general skull dimensions to localized functional optima through evolution. PMID:23734244

Testing adaptive hypotheses of convergence with functional landscapes: a case study of bone-cracking hypercarnivores.

Directory of Open Access Journals (Sweden)

Zhijie Jack Tseng

Full Text Available Morphological convergence is a well documented phenomenon in mammals, and adaptive explanations are commonly employed to infer similar functions for convergent characteristics. I present a study that adopts aspects of theoretical morphology and engineering optimization to test hypotheses about adaptive convergent evolution. Bone-cracking ecomorphologies in Carnivora were used as a case study. Previous research has shown that skull deepening and widening are major evolutionary patterns in convergent bone-cracking canids and hyaenids. A simple two-dimensional design space, with skull width-to-length and depth-to-length ratios as variables, was used to examine optimized shapes for two functional properties: mechanical advantage (MA and strain energy (SE. Functionality of theoretical skull shapes was studied using finite element analysis (FEA and visualized as functional landscapes. The distribution of actual skull shapes in the landscape showed a convergent trend of plesiomorphically low-MA and moderate-SE skulls evolving towards higher-MA and moderate-SE skulls; this is corroborated by FEA of 13 actual specimens. Nevertheless, regions exist in the landscape where high-MA and lower-SE shapes are not represented by existing species; their vacancy is observed even at higher taxonomic levels. Results highlight the interaction of biomechanical and non-biomechanical factors in constraining general skull dimensions to localized functional optima through evolution.

Testing statistical hypotheses

CERN Document Server

Lehmann, E L

2005-01-01

The third edition of Testing Statistical Hypotheses updates and expands upon the classic graduate text, emphasizing optimality theory for hypothesis testing and confidence sets. The principal additions include a rigorous treatment of large sample optimality, together with the requisite tools. In addition, an introduction to the theory of resampling methods such as the bootstrap is developed. The sections on multiple testing and goodness of fit testing are expanded. The text is suitable for Ph.D. students in statistics and includes over 300 new problems out of a total of more than 760. E.L. Lehmann is Professor of Statistics Emeritus at the University of California, Berkeley. He is a member of the National Academy of Sciences and the American Academy of Arts and Sciences, and the recipient of honorary degrees from the University of Leiden, The Netherlands and the University of Chicago. He is the author of Elements of Large-Sample Theory and (with George Casella) he is also the author of Theory of Point Estimat...

Testing statistical hypotheses of equivalence

CERN Document Server

Wellek, Stefan

2010-01-01

Equivalence testing has grown significantly in importance over the last two decades, especially as its relevance to a variety of applications has become understood. Yet published work on the general methodology remains scattered in specialists' journals, and for the most part, it focuses on the relatively narrow topic of bioequivalence assessment.With a far broader perspective, Testing Statistical Hypotheses of Equivalence provides the first comprehensive treatment of statistical equivalence testing. The author addresses a spectrum of specific, two-sided equivalence testing problems, from the

Mirror bootstrap method for testing hypotheses of one mean

OpenAIRE

Varvak, Anna

2012-01-01

The general philosophy for bootstrap or permutation methods for testing hypotheses is to simulate the variation of the test statistic by generating the sampling distribution which assumes both that the null hypothesis is true, and that the data in the sample is somehow representative of the population. This philosophy is inapplicable for testing hypotheses for a single parameter like the population mean, since the two assumptions are contradictory (e.g., how can we assume both that the mean o...

Current hypotheses on the mechanisms of alcoholism.

Science.gov (United States)

Vetreno, R P; Crews, F T

2014-01-01

Chronic use of alcohol results in progressive changes to brain and behavior that often lead to the development of alcohol dependence and alcoholism. Although the mechanisms underlying the development of alcoholism remain to be fully elucidated, diminished executive functioning due to hypoactive prefrontal cortex executive control and hyperactive limbic system anxiety and negative emotion might contribute mechanistically to the shift from experimental use to alcoholism and dependence. In the chapter that follows, behavioral deficits associated with cortical dysfunction and neurodegeneration will be related to the behavioral characteristics of alcoholism (e.g., diminished executive function, impulsivity, altered limbic modulation). We will provide evidence that alterations in cyclic AMP-responsive element binding protein (CREB: neurotrophic) and NF-κB (neuroimmune) signaling contribute to the development and persistence of alcoholism. In addition, genetic predispositions and an earlier age of drinking onset will be discussed as contributing factors to the development of alcohol dependence and alcoholism. Overall chronic ethanol-induced neuroimmune gene induction is proposed to alter limbic and frontal neuronal networks contributing to the development and persistence of alcoholism. © 2014 Elsevier B.V. All rights reserved.

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

Theoretical models of neutron emission in fission

International Nuclear Information System (INIS)

Madland, D.G.

1992-01-01

A brief survey of theoretical representations of two of the observables in neutron emission in fission is given, namely, the prompt fission neutron spectrum N(E) and the average prompt neutron multiplicity bar v p . Early representations of the two observables are presented and their deficiencies are discussed. This is followed by summaries and examples of recent theoretical models for the calculation of these quantities. Emphasis is placed upon the predictability and accuracy of the new models. In particular, the dependencies of N(E) and bar v p upon the fissioning nucleus and its excitation energy are treated. Recent work in the calculation of the prompt fission neutron spectrum matrix N(E,E n ), where E n is the energy of the neutron inducing fission, is then discussed. Concluding remarks address the current status of our ability to calculate these observables with confidence, the direction of future theoretical efforts, and limititations to current and future calculations. Finally, recommendations are presented as to which model should be used currently and which model should be pursued in future efforts

Evaluating hypotheses in geolocation on a very large sample of Twitter

DEFF Research Database (Denmark)

Salehi, Bahar; Søgaard, Anders

2017-01-01

Recent work in geolocation has madeseveral hypotheses about what linguisticmarkers are relevant to detect where peoplewrite from. In this paper, we examinesix hypotheses against a corpus consistingof all geo-tagged tweets from theUS, or whose geo-tags could be inferred,in a 19% sample of Twitter...

Current and Current Fluctuations in Quantum Shuttles

DEFF Research Database (Denmark)

Jauho, Antti-Pekka; Flindt, Christian; Novotny, Tomas

2005-01-01

theoretical tools needed for the analysis, e.g., generalized master equations and Wigner functions, and we outline the methods how the resulting large numerical problems can be handled. Illustrative results are given for current, noise, and full counting statistics for a number of model systems. Throughout...... the review we focus on the physics behind the various approximations, and some simple examples are given to illustrate the theoretical concepts. We also comment on the experimental situation. ©2005 American Institute of Physics...

Cryogenic current leads

Energy Technology Data Exchange (ETDEWEB)

Zizek, F.

1982-01-01

Theoretical, technical and design questions are examined of cryogenic current leads for SP of magnetic systems. Simplified mathematical models are presented for the current leads. To illustrate modeling, the calculation is made of the real current leads for 500 A and three variants of current leads for 1500 A for the enterprise ''Shkoda.''

Causes of bat fatalities at wind turbines: Hypotheses and predictions

Science.gov (United States)

Cryan, P.M.; Barclay, R.M.R.

2009-01-01

Thousands of industrial-scale wind turbines are being built across the world each year to meet the growing demand for sustainable energy. Bats of certain species are dying at wind turbines in unprecedented numbers. Species of bats consistently affected by turbines tend to be those that rely on trees as roosts and most migrate long distances. Although considerable progress has been made in recent years toward better understanding the problem, the causes of bat fatalities at turbines remain unclear. In this synthesis, we review hypothesized causes of bat fatalities at turbines. Hypotheses of cause fall into 2 general categoriesproximate and ultimate. Proximate causes explain the direct means by which bats die at turbines and include collision with towers and rotating blades, and barotrauma. Ultimate causes explain why bats come close to turbines and include 3 general types: random collisions, coincidental collisions, and collisions that result from attraction of bats to turbines. The random collision hypothesis posits that interactions between bats and turbines are random events and that fatalities are representative of the bats present at a site. Coincidental hypotheses posit that certain aspects of bat distribution or behavior put them at risk of collision and include aggregation during migration and seasonal increases in flight activity associated with feeding or mating. A surprising number of attraction hypotheses suggest that bats might be attracted to turbines out of curiosity, misperception, or as potential feeding, roosting, flocking, and mating opportunities. Identifying, prioritizing, and testing hypothesized causes of bat collisions with wind turbines are vital steps toward developing practical solutions to the problem. ?? 2009 American Society of Mammalogists.

Adaptive hatching hypotheses do not explain asynchronous ...

African Journals Online (AJOL)

At the core of the suite of adaptive hatching hypotheses advanced to explain asynchronous hatching in birds is the assumption that if food is not limited then all the hatchlings will develop normally to adulthood. In this study Brown-headed Parrot Poicephalus cryptoxanthus chicks were hand fed and weighed on a daily basis.

Theoretical study of a flat eddy current probe

International Nuclear Information System (INIS)

Bouchard, A.; Dumont-Fillon, J.; Labbe, G.

1976-01-01

A mathematical model for the computation of the impedance of an eddy current probe has been determined in the case of flat product testing. Various applications are discussed with particular emphasis on ferromagnetic materials [fr

Merging Theoretical Models and Therapy Approaches in the Context of Internet Gaming Disorder: A Personal Perspective

Science.gov (United States)

Young, Kimberly S.; Brand, Matthias

2017-01-01

Although, it is not yet officially recognized as a clinical entity which is diagnosable, Internet Gaming Disorder (IGD) has been included in section III for further study in the DSM-5 by the American Psychiatric Association (APA, 2013). This is important because there is increasing evidence that people of all ages, in particular teens and young adults, are facing very real and sometimes very severe consequences in daily life resulting from an addictive use of online games. This article summarizes general aspects of IGD including diagnostic criteria and arguments for the classification as an addictive disorder including evidence from neurobiological studies. Based on previous theoretical considerations and empirical findings, this paper examines the use of one recently proposed model, the Interaction of Person-Affect-Cognition-Execution (I-PACE) model, for inspiring future research and for developing new treatment protocols for IGD. The I-PACE model is a theoretical framework that explains symptoms of Internet addiction by looking at interactions between predisposing factors, moderators, and mediators in combination with reduced executive functioning and diminished decision making. Finally, the paper discusses how current treatment protocols focusing on Cognitive-Behavioral Therapy for Internet addiction (CBT-IA) fit with the processes hypothesized in the I-PACE model. PMID:29104555

Merging Theoretical Models and Therapy Approaches in the Context of Internet Gaming Disorder: A Personal Perspective.

Science.gov (United States)

Young, Kimberly S; Brand, Matthias

2017-01-01

Although, it is not yet officially recognized as a clinical entity which is diagnosable, Internet Gaming Disorder (IGD) has been included in section III for further study in the DSM-5 by the American Psychiatric Association (APA, 2013). This is important because there is increasing evidence that people of all ages, in particular teens and young adults, are facing very real and sometimes very severe consequences in daily life resulting from an addictive use of online games. This article summarizes general aspects of IGD including diagnostic criteria and arguments for the classification as an addictive disorder including evidence from neurobiological studies. Based on previous theoretical considerations and empirical findings, this paper examines the use of one recently proposed model, the Interaction of Person-Affect-Cognition-Execution (I-PACE) model, for inspiring future research and for developing new treatment protocols for IGD. The I-PACE model is a theoretical framework that explains symptoms of Internet addiction by looking at interactions between predisposing factors, moderators, and mediators in combination with reduced executive functioning and diminished decision making. Finally, the paper discusses how current treatment protocols focusing on Cognitive-Behavioral Therapy for Internet addiction (CBT-IA) fit with the processes hypothesized in the I-PACE model.

Merging Theoretical Models and Therapy Approaches in the Context of Internet Gaming Disorder: A Personal Perspective

Directory of Open Access Journals (Sweden)

Kimberly S. Young

2017-10-01

Full Text Available Although, it is not yet officially recognized as a clinical entity which is diagnosable, Internet Gaming Disorder (IGD has been included in section III for further study in the DSM-5 by the American Psychiatric Association (APA, 2013. This is important because there is increasing evidence that people of all ages, in particular teens and young adults, are facing very real and sometimes very severe consequences in daily life resulting from an addictive use of online games. This article summarizes general aspects of IGD including diagnostic criteria and arguments for the classification as an addictive disorder including evidence from neurobiological studies. Based on previous theoretical considerations and empirical findings, this paper examines the use of one recently proposed model, the Interaction of Person-Affect-Cognition-Execution (I-PACE model, for inspiring future research and for developing new treatment protocols for IGD. The I-PACE model is a theoretical framework that explains symptoms of Internet addiction by looking at interactions between predisposing factors, moderators, and mediators in combination with reduced executive functioning and diminished decision making. Finally, the paper discusses how current treatment protocols focusing on Cognitive-Behavioral Therapy for Internet addiction (CBT-IA fit with the processes hypothesized in the I-PACE model.

Current status of antiproton impact ionization of atoms and molecules: theoretical and experimental perspectives

DEFF Research Database (Denmark)

Kirchner, Tom; Knudsen, Helge

2011-01-01

Experimental and theoretical progress in the field of antiproton-impact-induced ionization of atoms and molecules is reviewed. We describe the techniques used to measure ionization cross sections and give an overview of the experimental results supplemented by tables of all existing data. An atte......Experimental and theoretical progress in the field of antiproton-impact-induced ionization of atoms and molecules is reviewed. We describe the techniques used to measure ionization cross sections and give an overview of the experimental results supplemented by tables of all existing data...

Application of a two fluid theoretical plasma transport model on current tokamak reactor designs

International Nuclear Information System (INIS)

Ibrahim, E.; Fowler, T.K.

1987-06-01

In this work, the new theoretical transport models to TIBER II design calculations are described and the results are compared with recent experimental data in large tokamaks (TFTR, JET). Tang's method is extended to a two-fluid model treating ions and electrons separately. This allows for different ion and electron temperatures, as in recent low-density experiments in TFTR, and in the TIBER II design itself. The discussion is divided into two parts: (1) Development of the theoretical transport model and (2) calibration against experiments and application to TIBER II

Cancer stem cell hypotheses: Impact on modern molecular

Indian Academy of Sciences (India)

basis for the so-called cancer stem cell (CSC) hypotheses. The first exact proof of CSC ... or less equal ability for tumour regeneration and repopulation. (Nowell 1976 .... Also, there are reports that the 'stemness' (stem-like properties) of brain.

A novel approach to generating CER hypotheses based on mining clinical data.

Science.gov (United States)

Zhang, Shuo; Li, Lin; Yu, Yiqin; Sun, Xingzhi; Xu, Linhao; Zhao, Wei; Teng, Xiaofei; Pan, Yue

2013-01-01

Comparative effectiveness research (CER) is a scientific method of investigating the effectiveness of alternative intervention methods. In a CER study, clinical researchers typically start with a CER hypothesis, and aim to evaluate it by applying a series of medical statistical methods. Traditionally, the CER hypotheses are defined manually by clinical researchers. This makes the task of hypothesis generation very time-consuming and the quality of hypothesis heavily dependent on the researchers' skills. Recently, with more electronic medical data being collected, it is highly promising to apply the computerized method for discovering CER hypotheses from clinical data sets. In this poster, we proposes a novel approach to automatically generating CER hypotheses based on mining clinical data, and presents a case study showing that the approach can facilitate clinical researchers to identify potentially valuable hypotheses and eventually define high quality CER studies.

Theoretical physics

International Nuclear Information System (INIS)

Anon.

1980-01-01

The nuclear theory program deals with the properties of nuclei and with the reactions and interactions between nuclei and a variety of projectiles. The main areas of concentration are: heavy-ion direct reactions at nonrelativistic energies; nuclear shell theory and nuclear structure; nuclear matter and nuclear forces;intermediate-energy physics and pion-nucleus interactions; and high-energy collisions of heavy ions. Recent progress and plans for future work in these five main areas of concentration and a summary of other theoretical studies currently in progress or recently completed are presented

Testing hypotheses involving Cronbach's alpha using marginal models

NARCIS (Netherlands)

Kuijpers, R.E.; van der Ark, L.A.; Croon, M.A.

2013-01-01

We discuss the statistical testing of three relevant hypotheses involving Cronbach's alpha: one where alpha equals a particular criterion; a second testing the equality of two alpha coefficients for independent samples; and a third testing the equality of two alpha coefficients for dependent

Borosilicate nuclear waste glass alteration kinetics theoretical basis for the kinetic law of nuclear glass alteration

International Nuclear Information System (INIS)

Jegou, Ch.; Gin, St.; Advocat, Th.; Vernaz, E.

1997-01-01

Work carried out since the early 1980's to predict the long-term behavior of nuclear containment glasses has revealed the inadequacy of existing models, notably in accounting for the fundamental mechanisms involved in some complex systems (e.g. glass-water-clay), inciting us to examine and discuss the theoretical basis for the hypotheses generally assumed in our models. This paper discusses the theoretical basis for the Aagaard-Helgeson law and its application to nuclear glasses. The contribution of other types of kinetic laws is also considered to describe the alteration kinetics of nuclear glasses. (authors)

A Bayesian decision procedure for testing multiple hypotheses in DNA microarray experiments.

Science.gov (United States)

Gómez-Villegas, Miguel A; Salazar, Isabel; Sanz, Luis

2014-02-01

DNA microarray experiments require the use of multiple hypothesis testing procedures because thousands of hypotheses are simultaneously tested. We deal with this problem from a Bayesian decision theory perspective. We propose a decision criterion based on an estimation of the number of false null hypotheses (FNH), taking as an error measure the proportion of the posterior expected number of false positives with respect to the estimated number of true null hypotheses. The methodology is applied to a Gaussian model when testing bilateral hypotheses. The procedure is illustrated with both simulated and real data examples and the results are compared to those obtained by the Bayes rule when an additive loss function is considered for each joint action and the generalized loss 0-1 function for each individual action. Our procedure significantly reduced the percentage of false negatives whereas the percentage of false positives remains at an acceptable level.

Data-driven efficient score tests for deconvolution hypotheses

NARCIS (Netherlands)

Langovoy, M.

2008-01-01

We consider testing statistical hypotheses about densities of signals in deconvolution models. A new approach to this problem is proposed. We constructed score tests for the deconvolution density testing with the known noise density and efficient score tests for the case of unknown density. The

Theoretical Developments In Environmental Management Accounting And The Role And Importance Of MFCA

Directory of Open Access Journals (Sweden)

Doorasamy Mishelle

2015-06-01

Full Text Available Environmental Management Accounting (EMA is a broader concept of accounting which uses accounting tools and practices to support company-internal management decision making on environmental issues and its impact on company performance. Research on EMA can be divided into two broad categories: theoretical and empirical studies. The theoretical studies based on framework that aim to explain the nature of the relationship between economic and environmental performance and the adoption of Environmental Management Accounting in a business environment. The empirical studies follow two lines of research, instrumental studies aim to empirically test the relationships hypothesized in theoretical studies; descriptive studies are intended to examine the factors that encourage the adoption of EMA. This review paper examined the role of MFCA in identifying non-product output (waste and its impact on an organisations profitability. Various case studies are examined in this article that demonstrates MFCA to an important environmental management tool to ensure future sustainability of an organisation.

Theoretical atomic physics

CERN Document Server

Friedrich, Harald

2017-01-01

This expanded and updated well-established textbook contains an advanced presentation of quantum mechanics adapted to the requirements of modern atomic physics. It includes topics of current interest such as semiclassical theory, chaos, atom optics and Bose-Einstein condensation in atomic gases. In order to facilitate the consolidation of the material covered, various problems are included, together with complete solutions. The emphasis on theory enables the reader to appreciate the fundamental assumptions underlying standard theoretical constructs and to embark on independent research projects. The fourth edition of Theoretical Atomic Physics contains an updated treatment of the sections involving scattering theory and near-threshold phenomena manifest in the behaviour of cold atoms (and molecules). Special attention is given to the quantization of weakly bound states just below the continuum threshold and to low-energy scattering and quantum reflection just above. Particular emphasis is laid on the fundamen...

Toward Valid Measurement of Stephen Pepper's World Hypotheses.

Science.gov (United States)

Johnson, John A.

Two measures of the "world hypotheses" of Stephen Pepper were mailed to 100 sociobiologists, 87 behaviorists, 79 personality psychologists, and 45 human developmentalists. The World Hypothesis Scale (WHS) was designed to measure Pepper's four world views: (1) formism; (2) mechanism; (3) organicism; and (4) contextualism. The…

Current lead thermal analysis code 'CURRENT'

International Nuclear Information System (INIS)

Yamaguchi, Masahito; Tada, Eisuke; Shimamoto, Susumu; Hata, Kenichiro.

1985-08-01

Large gas-cooled current lead with the capacity more than 30 kA and 22 kV is required for superconducting toroidal and poloidal coils for fusion application. The current lead is used to carry electrical current from the power supply system at room temperature to the superconducting coil at 4 K. Accordingly, the thermal performance of the current lead is significantly important to determine the heat load requirements of the coil system at 4 K. Japan Atomic Energy Research Institute (JAERI) has being developed the large gas-cooled current leads with the optimum condition in which the heat load is around 1 W per 1 kA at 4 K. In order to design the current lead with the optimum thermal performances, JAERI developed thermal analysis code named as ''CURRENT'' which can theoretically calculate the optimum geometric shape and cooling conditions of the current lead. The basic equations and the instruction manual of the analysis code are described in this report. (author)

Dark matter: Theoretical perspectives

International Nuclear Information System (INIS)

Turner, M.S.

1993-01-01

I both review and make the case for the current theoretical prejudice: a flat Universe whose dominant constituent is nonbaryonic dark matter, emphasizing that this is still a prejudice and not yet fact. The theoretical motivation for nonbaryonic dark matter is discussed in the context of current elementary-particle theory, stressing that: (1) there are no dark matter candidates within the standard model of particle physics; (2) there are several compelling candidates within attractive extensions of the standard model of particle physics; and (3) the motivation for these compelling candidates comes first and foremost from particle physics. The dark-matter problem is now a pressing issue in both cosmology and particle physics, and the detection of particle dark matter would provide evidence for ''new physics.'' The compelling candidates are: a very light axion ( 10 -6 eV--10 -4 eV); a light neutrino (20 eV--90 eV); and a heavy neutralino (10 GeV--2 TeV). The production of these particles in the early Universe and the prospects for their detection are also discussed. I briefly mention more exotic possibilities for the dark matter, including a nonzero cosmological constant, superheavy magnetic monopoles, and decaying neutrinos

Numerical and theoretical evaluations of AC losses for single and infinite numbers of superconductor strips with direct and alternating transport currents in external AC magnetic field

Science.gov (United States)

Kajikawa, K.; Funaki, K.; Shikimachi, K.; Hirano, N.; Nagaya, S.

2010-11-01

AC losses in a superconductor strip are numerically evaluated by means of a finite element method formulated with a current vector potential. The expressions of AC losses in an infinite slab that corresponds to a simple model of infinitely stacked strips are also derived theoretically. It is assumed that the voltage-current characteristics of the superconductors are represented by Bean's critical state model. The typical operation pattern of a Superconducting Magnetic Energy Storage (SMES) coil with direct and alternating transport currents in an external AC magnetic field is taken into account as the electromagnetic environment for both the single strip and the infinite slab. By using the obtained results of AC losses, the influences of the transport currents on the total losses are discussed quantitatively.

What Is the Problem of Ad Hoc Hypotheses?

Science.gov (United States)

Bamford, Greg

1999-01-01

Philosophers' attempts to convincingly explicate the received view of an ad hoc hypothesis--that it accounts for only the observations it was designed to account for--have been unsuccessful. Familiar and firmer criteria for evaluating the hypotheses or modified theories so classified are characteristically available. Contains 41 references.…

For a new dialogue between theoretical and empirical studies in evo-devo

Directory of Open Access Journals (Sweden)

Giuseppe eFusco

2015-08-01

Full Text Available Despite its potentially broad scope, current evo-devo research is largely dominated by empirical developmental studies, whereas comparably little role is played by theoretical research. I argue that this represents an obstacle to a wider appreciation of evo-devo and its integration within a more comprehensive evolutionary theory, and that this situation is causally linked to a limited exchange between theoretical and experimental studies in evo-devo. I discuss some features of current theoretical work in evo-devo, highlighting some possibly concurring impediments to an effective dialogue with experimental studies. Finally, I advance two suggestions for enhancing fruitful cross-fertilization between theoretical and empirical studies in evo-devo: i to broaden the scope of evo-devo beyond its current conceptualization, teaming up with other variational approaches to the study of evolution, and ii to develop more effective forms of scientific interaction and communication.

Electroconvulsive therapy's mechanism of action: neuroendocrine hypotheses.

Science.gov (United States)

Haskett, Roger F

2014-06-01

Despite a range of etiological theories since the introduction of electroconvulsive therapy (ECT) more than 75 years ago, its mechanism of action remains poorly understood. The neuroendocrine hypothesis is based on the seizure-related release of hypothalamic hormones into the blood and cerebrospinal fluid and evidence of endocrine dysfunction in many patients with severe mood disorder. The specific effect of ECT was hypothesized to result from the transverse passage of current through the brain with direct stimulation of axial structures including the diencephalon. The prompt release of adrenocorticotropic hormone, cortisol, and prolactin into blood followed ECT with a return to pretreatment baseline levels in several hours. The elevated levels of hormones were absorbed by the cerebrospinal fluid, providing contact with brain cells and central nervous system structures. An apparently specific pattern of ECT-induced hormone changes, limited to prolactin and cortisol, suggested that ECT released a substance with dopaminergic antagonist and antipsychotic properties. As hypothalamic dysfunction is a key finding in endogenomorphic depression and the abnormal endocrine and physiological functions usually normalize with recovery, this led to a search for biological markers that would supplement clinical assessment of diagnosis and treatment response. One of these, the overnight dexamethasone suppression test found that 40% to 50% of melancholic depressed patients had abnormal results, whereas 90% of control patients suppressed normally. This was followed by a period of uncritical overenthusiasm followed by wholesale rejection of the clinical neuroendocrine strategies. Several key methodological issues received inadequate attention, and there have been calls to revisit this topic.

Revisiting the environmental Kuznets curve and pollution haven hypotheses: MIKTA sample.

Science.gov (United States)

Bakirtas, Ibrahim; Cetin, Mumin Atalay

2017-08-01

This study aims to examine the validity of the environmental Kuznets curve (EKC) and pollution haven hypotheses in Mexico, Indonesia, South Korea, Turkey, and Australia (MIKTA) countries from 1982 to 2011 by using a panel vector auto regressive (PVAR) model. Empirical findings imply that the EKC hypothesis is rejected by the MIKTA sample. However, PVAR estimations reveal Granger causality from income level, foreign direct investment (FDI) inward, and energy consumption to CO 2 emissions. Orthogonalized impulse-response functions are derived from PVAR estimations. According to the analysis results, the response of CO 2 emissions to a shock on FDI is positive. These results assert that FDI has a detrimental effect on environmental quality in MIKTA countries which means the pollution haven hypothesis is confirmed by the MIKTA sample. Therefore, MIKTA countries should revise their current economic growth plans to provide sustainable development and also re-organize their legal infrastructure to induce usage of renewable energy sources.

Black/White Differences in Adolescent Drug Use: A Test of Six Hypotheses

Science.gov (United States)

Rote, Sunshine M.; Taylor, John

2014-01-01

Six specific hypotheses have been developed to account for why Caucasians have higher rates of drug use compared to African-Americans. This article utilizes data from a South Florida-based community study of 893 young adults (1998-2002) to test these hypotheses. Specifically, Caucasians (1) initiate drug use at younger ages than African-Americans…

Experimental and Theoretical Investigation of Shock-Induced Reactions in Energetic Materials

Energy Technology Data Exchange (ETDEWEB)

Kay, Jeffrey J. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Park, Samuel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kohl, Ian Thomas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Knepper, Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Farrow, Darcie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tappan, Alexander S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-09-01

In this work, shock-induced reactions in high explosives and their chemical mechanisms were investigated using state-of-the-art experimental and theoretical techniques. Experimentally, ultrafast shock interrogation (USI, an ultrafast interferometry technique) and ultrafast absorption spectroscopy were used to interrogate shock compression and initiation of reaction on the picosecond timescale. The experiments yielded important new data that appear to indicate reaction of high explosives on the timescale of tens of picoseconds in response to shock compression, potentially setting new upper limits on the timescale of reaction. Theoretically, chemical mechanisms of shock-induced reactions were investigated using density functional theory. The calculations generated important insights regarding the ability of several hypothesized mechanisms to account for shock-induced reactions in explosive materials. The results of this work constitute significant advances in our understanding of the fundamental chemical reaction mechanisms that control explosive sensitivity and initiation of detonation.

Rescripting Memory, Redefining the Self: A Meta-Emotional Perspective on the Hypothesized Mechanism(s of Imagery Rescripting

Directory of Open Access Journals (Sweden)

Alessandra Mancini

2018-04-01

Full Text Available Imagery Rescripting (ImRs is a therapeutic technique that aims to reduce the distress associated with negative memories of early aversive experiences. It consists of prompting patients to rescript the autobiographical memory in line with their unmet needs. In recent years, ImRs was found effective in reducing symptoms of disorders such as depression, social phobia, obsessive-compulsive disorder, post-traumatic stress disorder, and personality disorders. However, the cognitive mechanisms underlying such broad effectiveness are currently an object of debate. Empirical evidence has shown that ImRs reduces the negative self-belief derived from aversive memories in different types of mental disorders. However, existing accounts are not very accurate in explaining how this change in self-belief occurs and therefore why ImRs is effective across psychopathologies. We propose that ImRs changes the semantic self-representation encapsulated in the aversive memory by reducing the meta-emotional problem (i.e., perceiving a negative emotion as problematic and unacceptable. Empirical evidence implicates the meta-emotional problem or “secondary problem” in the maintenance of different disorders and has shown that treating it leads to symptoms reduction. Here we hypothesize that: (i ImRs as a stand-alone treatment may lead to a reduction of symptoms; negative self-belief and the meta-emotional problem; and (ii the reduction of the meta-emotional problem might mediate the relation between symptoms and negative self-belief reduction. To test our hypothesis, we present an experimental procedure that could be used in future studies. We conclude discussing the existing theoretical frameworks that attempt to unravel the mechanisms that play a role in ImRs.

Human memory research: Current hypotheses and new perspectives

Directory of Open Access Journals (Sweden)

Antônio Jaeger

Full Text Available Abstract Research on human memory has increased significantly in the last few decades. Inconsistencies and controversies inherent to such research, however, are rarely articulated on published reports. The goal of the present article is to present and discuss a series of open questions related to major topics on human memory research that can be addressed by future research. The topics covered here are visual working memory, recognition memory, emotion and memory interaction, and methodological issues of false memories studies. Overall, the present work reveals a series of open questions and alternative analysis which could be useful for the process of hypothesis generation, and consequently for the design and implementation of future research on human memory.

Current hypotheses and research milestones in Alzheimer's disease

National Research Council Canada - National Science Library

Maccioni, Ricardo B; Perry, George

2009-01-01

.... This book contains 20 seminal chapters by authors with different views that in a multidisciplinary approach focus on the main issues of neuroanatomical, neuropathological, neuropsychological, neurological, and molecular biological aspects of AD. The idea for this collection arose during the preparation of the proceedings for the International Summit Meeting...

Current Hypotheses on How Microsatellite Instability Leads to Enhanced Survival of Lynch Syndrome Patients

Directory of Open Access Journals (Sweden)

Kristen M. Drescher

2010-01-01

Full Text Available High levels of microsatellite instability (MSI-high are a cardinal feature of colorectal tumors from patients with Lynch Syndrome. Other key characteristics of Lynch Syndrome are that these patients experience fewer metastases and have enhanced survival when compared to patients diagnosed with microsatellite stable (MSS colorectal cancer. Many of the characteristics associated with Lynch Syndrome including enhanced survival are also observed in patients with sporadic MSI-high colorectal cancer. In this review we will present the current state of knowledge regarding the mechanisms that are utilized by the host to control colorectal cancer in Lynch Syndrome and why these same mechanisms fail in MSS colorectal cancers.

Current hypotheses on how microsatellite instability leads to enhanced survival of Lynch Syndrome patients.

Science.gov (United States)

Drescher, Kristen M; Sharma, Poonam; Lynch, Henry T

2010-01-01

High levels of microsatellite instability (MSI-high) are a cardinal feature of colorectal tumors from patients with Lynch Syndrome. Other key characteristics of Lynch Syndrome are that these patients experience fewer metastases and have enhanced survival when compared to patients diagnosed with microsatellite stable (MSS) colorectal cancer. Many of the characteristics associated with Lynch Syndrome including enhanced survival are also observed in patients with sporadic MSI-high colorectal cancer. In this review we will present the current state of knowledge regarding the mechanisms that are utilized by the host to control colorectal cancer in Lynch Syndrome and why these same mechanisms fail in MSS colorectal cancers.

Siblings of Youth with Autism Spectrum Disorders: Theoretical Perspectives on Sibling Relationships and Individual Adjustment

Science.gov (United States)

McHale, Susan M.; Updegraff, Kimberly A.; Feinberg, Mark E.

2015-01-01

A burgeoning research literature investigates the sibling relationships of youth with Autism Spectrum Disorder (ASD) and their implications for individual adjustment. Focusing on four relationship domains-- behaviors, emotions, cognitions and involvement—and toward advancing this generally atheoretical literature, we review and apply tenets from a range of theoretical perspectives in an effort to illuminate the mechanisms underlying sibling relationship experiences and their adjustment implications. Our review suggests new directions for research to test theoretically-grounded hypotheses about how sibling relationships develop and are linked to individual adjustment. In addition, we consider how identifying underlying bio-psycho-social processes can aid in the development of interventions to promote warm and involved sibling relationships and positive youth development. PMID:26476737

Twelve testable hypotheses on the geobiology of weathering

Science.gov (United States)

S.L. Brantley; J.P. Megonigal; F.N. Scatena; Z. Balogh-Brunstad; R.T. Barnes; M.A. Bruns; P. van Cappelen; K. Dontsova; H.E. Hartnett; A.S. Hartshorn; A. Heimsath; E. Herndon; L. Jin; C.K. Keller; J.R. Leake; W.H. McDowell; F.C. Meinzer; T.J. Mozdzer; S. Petsch; J. Pett-Ridge; K.S. Pretziger; P.A. Raymond; C.S. Riebe; K. Shumaker; A. Sutton-Grier; R. Walter; K. Yoo

2011-01-01

Critical Zone (CZ) research investigates the chemical, physical, and biological processes that modulate the Earth's surface. Here, we advance 12 hypotheses that must be tested to improve our understanding of the CZ: (1) Solar-to-chemical conversion of energy by plants regulates flows of carbon, water, and nutrients through plant-microbe soil networks, thereby...

Transfer factor - hypotheses for its structure and function.

Science.gov (United States)

Shifrine, M; Scibienski, R

1975-01-01

Transfer factor (TF) is a dialyzable extract from primed lymphocytes that is able to transfer specific delayed hypersensitivity from one animal to another. On the basis of available data we suggest that TF is a polypeptide with a molecular weight below 15,000 daltons. We hypothesize that TF is the variable light or heavy chain domain of immunoglobulin: such a molecule conforms with the accepted properties of TF and also has the necessary specificity requirements. We also hypothesize that TF is part of a receptor site. beta-2-microglobulin, a molecule that is an integral part of cell surfaces, could be the anchor for TF. beta-2-microglobulin has homologies with the constant portion of immunoglobulin light or heavy chain and thus would combine with the variable domain (TF) to form a complete receptor site for a specific antigen. The properties of TF suggest its mode of action, which is discussed in detail in the text. The biologic advantages of TF is its ability to confer immediate (immunologie specific) protection while the 'normal' immune response develops.

A survey of etiologic hypotheses among testicular cancer researchers

DEFF Research Database (Denmark)

Stang, A; Trabert, B; Rusner, C

2015-01-01

Basic research results can provide new ideas and hypotheses to be examined in epidemiological studies. We conducted a survey among testicular cancer researchers on hypotheses concerning the etiology of this malignancy. All researchers on the mailing list of Copenhagen Testis Cancer Workshops...... and corresponding authors of PubMed-indexed articles identified by the search term 'testicular cancer' and published within 10 years (in total 2750 recipients) were invited to respond to an e-mail-based survey. Participants of the 8th Copenhagen Testis Cancer Workshop in May 2014 were subsequently asked to rate...... that scored as most plausible. We also present plans for improving the survey that may be repeated at a next international meeting of experts in testicular cancer. Overall 52 of 99 (53%) registered participants of the 8th Copenhagen Testis Cancer Workshop submitted the plausibility rating form. Fourteen of 27...

Systematic review, structural analysis, and new theoretical perspectives on the role of serotonin and associated genes in the etiology of psychopathy and sociopathy

NARCIS (Netherlands)

Yildirim, B.O.; Derksen, J.J.L.

2013-01-01

Since its theoretical inception, psychopathy has been considered by philosophers, clinicians, theorists, and empirical researchers to be substantially and critically explained by genetic factors. In this systematic review and structural analysis, new hypotheses will be introduced regarding gene–gene

Ultra-Low Voltage Class AB Switched Current Memory Cell

DEFF Research Database (Denmark)

Igor, Mucha

1996-01-01

This paper presents the theoretical basis for the design of class AB switched current memory cells employing floating-gate MOS transistors, suitable for ultra-low-voltage applications. To support the theoretical assumptions circuits based on these cells were designed using a CMOS process with thr......This paper presents the theoretical basis for the design of class AB switched current memory cells employing floating-gate MOS transistors, suitable for ultra-low-voltage applications. To support the theoretical assumptions circuits based on these cells were designed using a CMOS process...... with threshold voltages of 0.9V. Both hand calculations and PSPICE simulations showed that the cells designed allowed a maximum signal range better than +/-13 micoamp, with a supply voltage down to 1V and a quiescent bias current of 1 microamp, resulting in a very high current efficiency and effective power...

The Meaning of Life among Secondary School Pupils. A Theoretical Framework and Some Initial Results. Research Bulletin 65.

Science.gov (United States)

Niemi, Hannele

This monograph reports on an empirical survey of 394 secondary school students investigating their desire to seek the meaning of their own lives. The theoretical framework upon which the study was based is that of Viktor E. Frankl's hypotheses that a human being wants to seek the meaning in his own life. The questionnaire consisted of tests…

Landscape moderation of biodiversity patterns and processes - eight hypotheses

NARCIS (Netherlands)

Tscharntke, T.; Tylianakis, J.M.; Rand, T.A.; Didham, R.K.; Fahrig, L.; Batary, P.; Bengtsson, J.; Clough, Y.; Crist, T.O.; Dormann, C.; Ewers, R.M.; Frund, J.; Holt, R.D.; Holzschuh, A.; Klein, A.M.; Kleijn, D.; Kremen, C.; Landis, D.A.; Laurance, W.F.; Lindenmayer, D.B.; Scherber, C.; Sodhi, N.; Steffan-Dewenter, I.; Thies, C.; Putten, van der W.H.; Westphal, C.

2012-01-01

Understanding how landscape characteristics affect biodiversity patterns and ecological processes at local and landscape scales is critical for mitigating effects of global environmental change. In this review, we use knowledge gained from human-modified landscapes to suggest eight hypotheses, which

Dark matter: Theoretical perspectives

International Nuclear Information System (INIS)

Turner, M.S.

1993-01-01

The author both reviews and makes the case for the current theoretical prejudice: a flat Universe whose dominant constituent is nonbaryonic dark matter, emphasizing that this is still a prejudice and not yet fact. The theoretical motivation for nonbaryonic dark matter is discussed in the context of current elementary-particle theory, stressing that (i) there are no dark-matter candidates within the open-quotes standard modelclose quotes of particle physics, (ii) there are several compelling candidates within attractive extensions of the standard model of particle physics, and (iii) the motivation for these compelling candidates comes first and foremost from particle physics. The dark-matter problem is now a pressing issue in both cosmology and particle physics, and the detection of particle dark matter would provide evidence for open-quotes new physics.close quotes The compelling candidates are a very light axion (10 -6 --10 -4 eV), a light neutrino (20--90 eV), and a heavy neutralino (10 GeV--2 TeV). The production of these particles in the early Universe and the prospects for their detection are also discussed. The author briefly mentions more exotic possibilities for the dark matter, including a nonzero cosmological constant, superheavy magnetic monopoles, and decaying neutrinos. 119 refs

Dark matter: Theoretical perspectives

Energy Technology Data Exchange (ETDEWEB)

Turner, M.S. (Chicago Univ., IL (United States). Enrico Fermi Inst. Fermi National Accelerator Lab., Batavia, IL (United States))

1993-01-01

I both review and make the case for the current theoretical prejudice: a flat Universe whose dominant constituent is nonbaryonic dark matter, emphasizing that this is still a prejudice and not yet fact. The theoretical motivation for nonbaryonic dark matter is discussed in the context of current elementary-particle theory, stressing that: (1) there are no dark matter candidates within the standard model of particle physics; (2) there are several compelling candidates within attractive extensions of the standard model of particle physics; and (3) the motivation for these compelling candidates comes first and foremost from particle physics. The dark-matter problem is now a pressing issue in both cosmology and particle physics, and the detection of particle dark matter would provide evidence for new physics.'' The compelling candidates are: a very light axion ( 10[sup [minus]6] eV--10[sup [minus]4] eV); a light neutrino (20 eV--90 eV); and a heavy neutralino (10 GeV--2 TeV). The production of these particles in the early Universe and the prospects for their detection are also discussed. I briefly mention more exotic possibilities for the dark matter, including a nonzero cosmological constant, superheavy magnetic monopoles, and decaying neutrinos.

Dark matter: Theoretical perspectives

Energy Technology Data Exchange (ETDEWEB)

Turner, M.S. [Chicago Univ., IL (United States). Enrico Fermi Inst.]|[Fermi National Accelerator Lab., Batavia, IL (United States)

1993-01-01

I both review and make the case for the current theoretical prejudice: a flat Universe whose dominant constituent is nonbaryonic dark matter, emphasizing that this is still a prejudice and not yet fact. The theoretical motivation for nonbaryonic dark matter is discussed in the context of current elementary-particle theory, stressing that: (1) there are no dark matter candidates within the standard model of particle physics; (2) there are several compelling candidates within attractive extensions of the standard model of particle physics; and (3) the motivation for these compelling candidates comes first and foremost from particle physics. The dark-matter problem is now a pressing issue in both cosmology and particle physics, and the detection of particle dark matter would provide evidence for ``new physics.`` The compelling candidates are: a very light axion ( 10{sup {minus}6} eV--10{sup {minus}4} eV); a light neutrino (20 eV--90 eV); and a heavy neutralino (10 GeV--2 TeV). The production of these particles in the early Universe and the prospects for their detection are also discussed. I briefly mention more exotic possibilities for the dark matter, including a nonzero cosmological constant, superheavy magnetic monopoles, and decaying neutrinos.

Towards Self-Learning Based Hypotheses Generation in Biomedical Text Domain.

Science.gov (United States)

Gopalakrishnan, Vishrawas; Jha, Kishlay; Xun, Guangxu; Ngo, Hung Q; Zhang, Aidong

2017-12-26

The overwhelming amount of research articles in the domain of bio-medicine might cause important connections to remain unnoticed. Literature Based Discovery is a sub-field within biomedical text mining that peruses these articles to formulate high confident hypotheses on possible connections between medical concepts. Although many alternate methodologies have been proposed over the last decade, they still suffer from scalability issues. The primary reason, apart from the dense inter-connections between biological concepts, is the absence of information on the factors that lead to the edge-formation. In this work, we formulate this problem as a collaborative filtering task and leverage a relatively new concept of word-vectors to learn and mimic the implicit edge-formation process. Along with single-class classifier, we prune the search-space of redundant and irrelevant hypotheses to increase the efficiency of the system and at the same time maintaining and in some cases even boosting the overall accuracy. We show that our proposed framework is able to prune up to 90% of the hypotheses while still retaining high recall in top-K results. This level of efficiency enables the discovery algorithm to look for higher-order hypotheses, something that was infeasible until now. Furthermore, the generic formulation allows our approach to be agile to performboth open and closed discovery.We also experimentally validate that the core data-structures upon which the system bases its decision has a high concordance with the opinion of the experts.This coupled with the ability to understand the edge formation process provides us with interpretable results without any manual intervention. The relevant JAVA codes are available at: https://github.com/vishrawas/Medline-Code_v2. vishrawa@buffalo.edukishlayj@buffalo.edu. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email

Experiments with eddy currents: the eddy current brake

International Nuclear Information System (INIS)

Gonzalez, Manuel I

2004-01-01

A moderate-cost experimental setup is presented to help students to understand some qualitative and quantitative aspects of eddy currents. The setup operates like an eddy current brake, a device commonly used in heavy vehicles to dissipate kinetic energy by generating eddy currents. A set of simple experiments is proposed to measure eddy current losses and to relate them to various relevant parameters. Typical results for each of the experiments are presented, and comparisons with theoretical predictions are included. The experiments, which are devoted to first-year undergraduate students, deal also with other pedagogically relevant topics in electricity and magnetism, such as basic laws, electrical measurement techniques, the sources of the magnetic field and others

THEORETICAL CONCEPTIONS OF GEOGRAPHY TEACHERS

Directory of Open Access Journals (Sweden)

Eloy Montes Galbán

2007-11-01

Full Text Available The main goal of this research was to determine the current theoretical concepts handled by third stage basic education geography teachers. A non experimental descriptive study was made. Data was collected through a semi structured questionnaire. The population was conformed by the teachers who work at the National schools placed in the parishes Raul Leoni and Cacique Mara of Maracaibo city, Zulia State. There is not clarity in regard to the correct handling of the different geographic currents, and the slight notion teachers have leans towards a traditional, descriptive, retrospective memory based conception.

Superconducting dc fault current limiter

International Nuclear Information System (INIS)

Cointe, Y.

2007-12-01

Within the framework of the electric power market liberalization, DC networks have many interests compared to alternative ones, but their protections need to use new systems. Superconducting fault current limiters enable by an overstepping of the critical current to limit the fault current to a preset value, lower than the theoretical short-circuit current. For these applications, coated conductors offer excellent opportunities. We worked on the implementation of these materials and built a test bench. We carried out limiting experiments to estimate the quench homogeneity at various short-circuit parameters. An important point is the temperature measurement by deposited sensors on the ribbon, results are in good correlation with the theoretical models. Improved quench behaviours for temperatures close to the critical temperature have been confirmed. Our results enable to better understand the limitation mechanisms of coated conductors. (author)

Testing Hypotheses About Glacial Cycles Against the Observational Record

DEFF Research Database (Denmark)

Kaufmann, Robert; Juselius, Katarina

2013-01-01

We estimate an identified cointegrated vector autoregression (CVAR) model of the climate system to test hypotheses about the physical mechanisms that may drive glacial cycles during the late Pleistocene. Results indicate that a permanent doubling of CO2 generates a 11.1oC rise in Antarctic...

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.

How faith heals: a theoretical model.

Science.gov (United States)

Levin, Jeff

2009-01-01

This paper summarizes theoretical perspectives from psychology supportive of a healing effect of faith. First, faith is defined as a congruence of belief, trust, and obedience in relation to God or the divine. Second, evidence for a faith-healing association is presented, empirically and in theory. To exemplify religiously sanctioned affirmation of such a connection, selected passages are cited from the Jewish canon attesting to biblical and rabbinic support for a faith factor in longevity, disease risk, mental health and well-being, disease prevention, and healing. Third, reference to theories of hope, learned optimism, positive illusions, and opening up or disclosure, and to theory and research on psychoneuroimmunology and placebos, demonstrates that contemporary psychology can accommodate a healing power of faith. This is summarized in a typology of five hypothesized mechanisms underlying a faith-healing association, termed behavioral/conative, interpersonal, cognitive, affective, and psychophysiological. Finally, implications are discussed for the rapprochement of religion and medicine.

Hybrid quantum teleportation: A theoretical model

Energy Technology Data Exchange (ETDEWEB)

Takeda, Shuntaro; Mizuta, Takahiro; Fuwa, Maria; Yoshikawa, Jun-ichi; Yonezawa, Hidehiro; Furusawa, Akira [Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

2014-12-04

Hybrid quantum teleportation – continuous-variable teleportation of qubits – is a promising approach for deterministically teleporting photonic qubits. We propose how to implement it with current technology. Our theoretical model shows that faithful qubit transfer can be achieved for this teleportation by choosing an optimal gain for the teleporter’s classical channel.

A theoretical model of multielectrode DBR lasers

DEFF Research Database (Denmark)

Pan, Xing; Olesen, Henning; Tromborg, Bjarne

1988-01-01

A theoretical model for two- and three-section tunable distributed Bragg reflector (DBR) lasers is presented. The static tuning properties are studied in terms of threshold current, linewidth, oscillation frequency, and output power. Regions of continuous tuning for three-section DBR lasers...

Testing a theoretical model of clinical nurses' intent to stay.

Science.gov (United States)

Cowden, Tracy L; Cummings, Greta G

2015-01-01

Published theoretical models of nurses' intent to stay (ITS) report inconsistent outcomes, and not all hypothesized models have been adequately tested. Research has focused on cognitive rather than emotional determinants of nurses' ITS. The aim of this study was to empirically verify a complex theoretical model of nurses' ITS that includes both affective and cognitive determinants and to explore the influence of relational leadership on staff nurses' ITS. The study was a correlational, mixed-method, nonexperimental design. A subsample of the Quality Work Environment Study survey data 2009 (n = 415 nurses) was used to test our theoretical model of clinical nurses' ITS as a structural equation model. The model explained 63% of variance in ITS. Organizational commitment, empowerment, and desire to stay were the model concepts with the strongest effects on nurses' ITS. Leadership practices indirectly influenced ITS. How nurses evaluate and respond to their work environment is both an emotional and rational process. Health care organizations need to be cognizant of the influence that nurses' feelings and views of their work setting have on their intention decisions and integrate that knowledge into the development of retention strategies. Leadership practices play an important role in staff nurses' perceptions of the workplace. Identifying the mechanisms by which leadership influences staff nurses' intentions to stay presents additional focus areas for developing retention strategies.

A theoretical model of water and trade

Science.gov (United States)

Dang, Qian; Konar, Megan; Reimer, Jeffrey J.; Di Baldassarre, Giuliano; Lin, Xiaowen; Zeng, Ruijie

2016-03-01

Water is an essential input for agricultural production. Agriculture, in turn, is globalized through the trade of agricultural commodities. In this paper, we develop a theoretical model that emphasizes four tradeoffs involving water-use decision-making that are important yet not always considered in a consistent framework. One tradeoff focuses on competition for water among different economic sectors. A second tradeoff examines the possibility that certain types of agricultural investments can offset water use. A third tradeoff explores the possibility that the rest of the world can be a source of supply or demand for a country's water-using commodities. The fourth tradeoff concerns how variability in water supplies influences farmer decision-making. We show conditions under which trade liberalization affect water use. Two policy scenarios to reduce water use are evaluated. First, we derive a target tax that reduces water use without offsetting the gains from trade liberalization, although important tradeoffs exist between economic performance and resource use. Second, we show how subsidization of water-saving technologies can allow producers to use less water without reducing agricultural production, making such subsidization an indirect means of influencing water use decision-making. Finally, we outline conditions under which riskiness of water availability affects water use. These theoretical model results generate hypotheses that can be tested empirically in future work.

Automatic Bayes Factors for Testing Equality- and Inequality-Constrained Hypotheses on Variances.

Science.gov (United States)

Böing-Messing, Florian; Mulder, Joris

2018-05-03

In comparing characteristics of independent populations, researchers frequently expect a certain structure of the population variances. These expectations can be formulated as hypotheses with equality and/or inequality constraints on the variances. In this article, we consider the Bayes factor for testing such (in)equality-constrained hypotheses on variances. Application of Bayes factors requires specification of a prior under every hypothesis to be tested. However, specifying subjective priors for variances based on prior information is a difficult task. We therefore consider so-called automatic or default Bayes factors. These methods avoid the need for the user to specify priors by using information from the sample data. We present three automatic Bayes factors for testing variances. The first is a Bayes factor with equal priors on all variances, where the priors are specified automatically using a small share of the information in the sample data. The second is the fractional Bayes factor, where a fraction of the likelihood is used for automatic prior specification. The third is an adjustment of the fractional Bayes factor such that the parsimony of inequality-constrained hypotheses is properly taken into account. The Bayes factors are evaluated by investigating different properties such as information consistency and large sample consistency. Based on this evaluation, it is concluded that the adjusted fractional Bayes factor is generally recommendable for testing equality- and inequality-constrained hypotheses on variances.

Some Theoretical and Methodological Problems Related to Studying the Future of Adult Education

Directory of Open Access Journals (Sweden)

Ilija Lavrnja

1995-12-01

Full Text Available The following paper first discusses some epistemological and theoretically methodological initial theses for a futurological research in education. In analysing them, the author first dwells upon different orientations and doctrines for futuro logical research work (rational detenninism and indetenninism, agnosticism and probabil· ism. This article is focusing upon possibilities and limits of hypotheses, related to the educational development in the future. In doing so, re-orientation or reconstruction of knowledge, educational phenomena and pedagogical thinking related to the education as a factor inducing individual and social development are taken into account.

Reflections on the conceptualization and operationalization of a set-theoretic approach to employee motivation and performance research

Directory of Open Access Journals (Sweden)

James Christopher Ryan

2017-01-01

Full Text Available The current commentary offers a reflection on the conceptualizations of Lee and Raschke's (2016 proposal for a set-theoretic approach to employee motivation and organizational performance. The commentary is informed by the current author's operationalization of set-theoretic research on employee motivation which occurred contemporaneously to the work of Lee and Raschke. Observations on the state of current research on employee motivation, development of motivation theory and future directions of set-theoretic approaches to employee motivation and performance are offered.

How do trees die? A test of the hydraulic failure and carbon starvation hypotheses

Science.gov (United States)

Sevanto, Sanna; Mcdowell, Nate G; Dickman, L Turin; Pangle, Robert; Pockman, William T

2014-01-01

Despite decades of research on plant drought tolerance, the physiological mechanisms by which trees succumb to drought are still under debate. We report results from an experiment designed to separate and test the current leading hypotheses of tree mortality. We show that piñon pine (Pinus edulis) trees can die of both hydraulic failure and carbon starvation, and that during drought, the loss of conductivity and carbohydrate reserves can also co-occur. Hydraulic constraints on plant carbohydrate use determined survival time: turgor loss in the phloem limited access to carbohydrate reserves, but hydraulic control of respiration prolonged survival. Our data also demonstrate that hydraulic failure may be associated with loss of adequate tissue carbohydrate content required for osmoregulation, which then promotes failure to maintain hydraulic integrity. PMID:23730972

Theoretical and experimental study of an energy-reinforced braking radiation photon beam

International Nuclear Information System (INIS)

Bertin, Pierre-Yves

1966-01-01

This research thesis reports the theoretical study of a photon beam raised towards high energies, its experimental implementation, the definition of a gamma spectrometry method which aimed at checking various hypotheses used in the beam theoretical study. After a presentation of the theory of phenomena of electron braking radiation, of materialisation of photons into positon-negaton pair, and of issues related to multiple Coulomb diffusion, the author reports the study of the different solutions which allow a photon beam to be obtained. A braking radiation of mono-kinetic electron has been used. This braking radiation is reinforced by absorption of low energy protons in a column of lithium hydride. The author describes how the beam is built up, and the experimental approach. He describes how raw data are processed to get rid of the influence of the multiple Coulomb diffusion and of the braking radiation. Experimental results are compared with those obtained by convolution of photon spectra and differential cross section

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.

Evolution of microgastropods (Ellobioidea, Carychiidae): integrating taxonomic, phylogenetic and evolutionary hypotheses

Science.gov (United States)

2013-01-01

Background Current biodiversity patterns are considered largely the result of past climatic and tectonic changes. In an integrative approach, we combine taxonomic and phylogenetic hypotheses to analyze temporal and geographic diversification of epigean (Carychium) and subterranean (Zospeum) evolutionary lineages in Carychiidae (Eupulmonata, Ellobioidea). We explicitly test three hypotheses: 1) morphospecies encompass unrecognized evolutionary lineages, 2) limited dispersal results in a close genetic relationship of geographical proximally distributed taxa and 3) major climatic and tectonic events had an impact on lineage diversification within Carychiidae. Results Initial morphospecies assignments were investigated by different molecular delimitation approaches (threshold, ABGD, GMYC and SP). Despite a conservative delimitation strategy, carychiid morphospecies comprise a great number of unrecognized evolutionary lineages. We attribute this phenomenon to historic underestimation of morphological stasis and phenotypic variability amongst lineages. The first molecular phylogenetic hypothesis for the Carychiidae (based on COI, 16S and H3) reveals Carychium and Zospeum to be reciprocally monophyletic. Geographical proximally distributed lineages are often closely related. The temporal diversification of Carychiidae is best described by a constant rate model of diversification. The evolution of Carychiidae is characterized by relatively few (long distance) colonization events. We find support for an Asian origin of Carychium. Zospeum may have arrived in Europe before extant members of Carychium. Distantly related Carychium clades inhabit a wide spectrum of the available bioclimatic niche and demonstrate considerable niche overlap. Conclusions Carychiid taxonomy is in dire need of revision. An inferred wide distribution and variable phenotype suggest underestimated diversity in Zospeum. Several Carychium morphospecies are results of past taxonomic lumping. By collecting

THEORETICAL PRESSUPOSITIONS OF EDUCATION: SOME HISTORICAL REFLECTIONS

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Rodrigo Regert

2017-09-01

Full Text Available Education has always been a much discussed theme and continues to be so. Based on this idea, the goal of this article is to discuss the theoretical pressupositions of education, beginning with the idea itself of human intellectual development and passing through the Ancient, Medieval, Modern and Contemporary Ages. It is important to point out that the article does not have the intention of covering the whole of this theme, nor even all of the theoretical pressupositions, which would be impossible. But it intends to begin or at least continue this discussion. For this the research made use of the descriptive method and its technical procedures took place in a bibliographic way. We conclude that it is important to discuss the theoretical pressupositions of education in history since, without this, it is not even possible to understand current education.

Comparison for aphasic and control subjects of eye movements hypothesized in neurolinguistic programming.

Science.gov (United States)

Dooley, K O; Farmer, A

1988-08-01

Neurolinguistic programming's hypothesized eye movements were measured independently using videotapes of 10 nonfluent aphasic and 10 control subjects matched for age and sex. Chi-squared analysis indicated that eye-position responses were significantly different for the groups. Although earlier research has not supported the hypothesized eye positions for normal subjects, the present findings support the contention that eye-position responses may differ between neurologically normal and aphasic individuals.

Theoretical calculations of physico-chemical and spectroscopic properties of bioinorganic systems: current limits and perspectives.

Science.gov (United States)

Rokob, Tibor András; Srnec, Martin; Rulíšek, Lubomír

2012-05-21

In the last decade, we have witnessed substantial progress in the development of quantum chemical methodologies. Simultaneously, robust solvation models and various combined quantum and molecular mechanical (QM/MM) approaches have become an integral part of quantum chemical programs. Along with the steady growth of computer power and, more importantly, the dramatic increase of the computer performance to price ratio, this has led to a situation where computational chemistry, when exercised with the proper amount of diligence and expertise, reproduces, predicts, and complements the experimental data. In this perspective, we review some of the latest achievements in the field of theoretical (quantum) bioinorganic chemistry, concentrating mostly on accurate calculations of the spectroscopic and physico-chemical properties of open-shell bioinorganic systems by wave-function (ab initio) and DFT methods. In our opinion, the one-to-one mapping between the calculated properties and individual molecular structures represents a major advantage of quantum chemical modelling since this type of information is very difficult to obtain experimentally. Once (and only once) the physico-chemical, thermodynamic and spectroscopic properties of complex bioinorganic systems are quantitatively reproduced by theoretical calculations may we consider the outcome of theoretical modelling, such as reaction profiles and the various decompositions of the calculated parameters into individual spatial or physical contributions, to be reliable. In an ideal situation, agreement between theory and experiment may imply that the practical problem at hand, such as the reaction mechanism of the studied metalloprotein, can be considered as essentially solved.

Diode-Assisted Buck-Boost Current Source Inverters

DEFF Research Database (Denmark)

Gao, F.; Cai, Liang; Loh, P.C.

2007-01-01

This paper presents a couple of novel current source inverters (CSIs) with the enhanced current buckboost capability. With the unique diode-inductor network added between current source inverter circuitry and current boost elements, the proposed buck-boost current source inverters demonstrate...... uninfluenced. Lastly, all theoretical findings were verified experimentally using constructed laboratory prototypes....

Cosmopolitanism: Extending Our Theoretical Framework for Transcultural Technical Communication Research and Teaching

Science.gov (United States)

Palmer, Zsuzsanna Bacsa

2013-01-01

The effects of globalization on communication products and processes have resulted in document features and interactional practices that are sometimes difficult to describe within current theoretical frameworks of inter/transcultural technical communication. Although it has been recognized in our field that the old theoretical frameworks and…

Risk, innovation, electricity infrastructure and construction cost overruns: Testing six hypotheses

International Nuclear Information System (INIS)

Sovacool, Benjamin K.; Gilbert, Alex; Nugent, Daniel

2014-01-01

This study investigates the frequency and magnitude of cost and time overruns occurring during the construction of 401 electricity projects built between 1936 and 2014 in 57 countries. In aggregate, these projects required approximately $820 billion in investment, and amounted to 325,515 MW of installed capacity and 8495 km of transmission lines. We use this sample of projects to test six hypotheses about construction cost overruns related to (1) diseconomies of scale, (2) project delays, (3) technological learning, (4) regulation and markets, (5) decentralization and modularity, and (6) normalization of results to scale. We find that nuclear reactors are the riskiest technology in terms of mean cost escalation as a percentage of budget and frequency; that hydroelectric dams stand apart for their mean cost escalation in total dollars; that many of the hypotheses grounded in the literature appear wrong; and that financing, partnerships, modularity, and accountability may have more to do with overruns than technology. - Highlights: • Many hypotheses about construction overruns grounded in the literature appear wrong. • Nuclear reactors are the most prone to cost overruns as a percentage of budget and frequency. • Hydroelectric dams stand apart for their mean cost escalation in total dollars. • Solar and wind energy systems are least at risk to cost overruns

Study of the instability of a film streaming on a vertical plane plate and submitted to a gas counter-current. Transition towards the co-current upward flow

International Nuclear Information System (INIS)

Bachir, Aziz

1987-01-01

This research thesis addresses the study of a liquid film flowing on a vertical wall in presence of a counter-current gas flow, and of its transition towards an upward co-current flow due to the increase of gas rate, such transition being herein called flooding. In the first part, the author addresses this flooding phenomenon and reports a bibliographical study of experimental and theoretical works. In the second part, he proposes an original theoretical approach to the modelling of a counter-current flow evolving towards a co-current flow: main methods of study of liquid film stability without gas flow, elaboration of the proposed model, study of the linear stability, numerical resolution, and presentation of an original theoretical criterion defining the limits of counter-current flow. The next part reports the experimental works: visualisations of mechanisms resulting in flooding in a rectangular duct, development of an experimental installation, comparison between theoretical and experimental results [fr

Experienced physicians benefit from analyzing initial diagnostic hypotheses

Science.gov (United States)

Bass, Adam; Geddes, Colin; Wright, Bruce; Coderre, Sylvain; Rikers, Remy; McLaughlin, Kevin

2013-01-01

Background Most incorrect diagnoses involve at least one cognitive error, of which premature closure is the most prevalent. While metacognitive strategies can mitigate premature closure in inexperienced learners, these are rarely studied in experienced physicians. Our objective here was to evaluate the effect of analytic information processing on diagnostic performance of nephrologists and nephrology residents. Methods We asked nine nephrologists and six nephrology residents at the University of Calgary and Glasgow University to diagnose ten nephrology cases. We provided presenting features along with contextual information, after which we asked for an initial diagnosis. We then primed participants to use either hypothetico-deductive reasoning or scheme-inductive reasoning to analyze the remaining case data and generate a final diagnosis. Results After analyzing initial hypotheses, both nephrologists and residents improved the accuracy of final diagnoses (31.1% vs. 65.6%, p inductive reasoning (odds ratio [95% confidence interval] 5.69 [1.59, 20.33], p = 0.07), whereas the performance of experienced nephrologists did not differ between strategies (odds ratio 0.57 [0.23, 1.39], p = 0.20). Discussion Experienced nephrologists and nephrology residents can improve their performance by analyzing initial diagnostic hypotheses. The explanation of the interaction between experience and the effect of different reasoning strategies is unclear, but may relate to preferences in reasoning strategy, or the changes in knowledge structure with experience. PMID:26451203

Kolmogorov's refined similarity hypotheses for turbulence and general stochastic processes

International Nuclear Information System (INIS)

Stolovitzky, G.; Sreenivasan, K.R.

1994-01-01

Kolmogorov's refined similarity hypotheses are shown to hold true for a variety of stochastic processes besides high-Reynolds-number turbulent flows, for which they were originally proposed. In particular, just as hypothesized for turbulence, there exists a variable V whose probability density function attains a universal form. Analytical expressions for the probability density function of V are obtained for Brownian motion as well as for the general case of fractional Brownian motion---the latter under some mild assumptions justified a posteriori. The properties of V for the case of antipersistent fractional Brownian motion with the Hurst exponent of 1/3 are similar in many details to those of high-Reynolds-number turbulence in atmospheric boundary layers a few meters above the ground. The one conspicuous difference between turbulence and the antipersistent fractional Brownian motion is that the latter does not possess the required skewness. Broad implications of these results are discussed

Information theoretic preattentive saliency

DEFF Research Database (Denmark)

Loog, Marco

2011-01-01

Employing an information theoretic operational definition of bottom-up attention from the field of computational visual perception a very general expression for saliency is provided. As opposed to many of the current approaches to determining a saliency map there is no need for an explicit data...... of which features, image information is described. We illustrate our result by determining a few specific saliency maps based on particular choices of features. One of them makes the link with the mapping underlying well-known Harris interest points, which is a result recently obtained in isolation...

Theoretical Optics An Introduction

CERN Document Server

Römer, Hartmann

2004-01-01

Starting from basic electrodynamics, this volume provides a solid, yet concise introduction to theoretical optics, containing topics such as nonlinear optics, light-matter interaction, and modern topics in quantum optics, including entanglement, cryptography, and quantum computation. The author, with many years of experience in teaching and research, goes way beyond the scope of traditional lectures, enabling readers to keep up with the current state of knowledge. Both content and presentation make it essential reading for graduate and phD students as well as a valuable reference for researche

The Role of Trait Emotional Intelligence in Academic Performance: Theoretical Overview and Empirical Update.

Science.gov (United States)

Perera, Harsha N

2016-01-01

Considerable debate still exists among scholars over the role of trait emotional intelligence (TEI) in academic performance. The dominant theoretical position is that TEI should be orthogonal or only weakly related to achievement; yet, there are strong theoretical reasons to believe that TEI plays a key role in performance. The purpose of the current article is to provide (a) an overview of the possible theoretical mechanisms linking TEI with achievement and (b) an update on empirical research examining this relationship. To elucidate these theoretical mechanisms, the overview draws on multiple theories of emotion and regulation, including TEI theory, social-functional accounts of emotion, and expectancy-value and psychobiological model of emotion and regulation. Although these theoretical accounts variously emphasize different variables as focal constructs, when taken together, they provide a comprehensive picture of the possible mechanisms linking TEI with achievement. In this regard, the article redresses the problem of vaguely specified theoretical links currently hampering progress in the field. The article closes with a consideration of directions for future research.

A set working hypotheses towards a unified view of the universe

International Nuclear Information System (INIS)

Kecher, J.-C.; Vigier, J.P.; Centre National de la Recherche Scientifique, 75 - Paris; Paris-6 Univ., 75

1976-01-01

Some observation evidence (anisotropy and inhomogeneity of the Hubble constant, abnormal red shifts) led the authors to formulate working hypotheses compatible with these observations. The logics of these hypotheses led to consider the universe as a ''hierarchical'' universe similar to Charlier one, and to find the cause of the apparent expansion in the interactions affecting the path of the photons. As, in some cases, intrinsic red shifts are very important this reduces the distance of the considered objects and their absolute luminosity, and forces to link them with ordinary galaxies; a scheme of evolution of extragalactic objects is suggested, to account for the geometrical location of abnormal objects, and for some aspects of their morphology. Coherent picture of the universe might emerge from the suggested studies

Modelling secondary instability of co-current a thin gas-sheared film

Energy Technology Data Exchange (ETDEWEB)

Vozhakov, I S; Cherdantsev, A V; Arkhipov, D G, E-mail: vozhakov@gmail.com [Kutateladze Institute of Thermophysics, Novosibirsk (Russian Federation)

2016-12-15

Recent experimental works found the existence of two types of waves on the surface of gas-sheared thin films. Slower short-living ‘secondary waves’ appear due to the instability of the rear slopes of faster long-living ‘primary waves’. In this paper, modelling of spatiotemporal evolution of liquid film in such kind of flows is performed using relatively simple theoretical models. The modelling results are directly compared with the experimental data. It is found that the phenomenon of secondary waves generation at the rear slopes of the primary waves is reproduced by the model. This allows us to reduce the number of hypotheses which explain the mechanism responsible for such instability. Recommendations for future theoretical investigations are proposed. (paper)

Modelling secondary instability of co-current a thin gas-sheared film

International Nuclear Information System (INIS)

Vozhakov, I S; Cherdantsev, A V; Arkhipov, D G

2016-01-01

Recent experimental works found the existence of two types of waves on the surface of gas-sheared thin films. Slower short-living ‘secondary waves’ appear due to the instability of the rear slopes of faster long-living ‘primary waves’. In this paper, modelling of spatiotemporal evolution of liquid film in such kind of flows is performed using relatively simple theoretical models. The modelling results are directly compared with the experimental data. It is found that the phenomenon of secondary waves generation at the rear slopes of the primary waves is reproduced by the model. This allows us to reduce the number of hypotheses which explain the mechanism responsible for such instability. Recommendations for future theoretical investigations are proposed. (paper)

Development of working hypotheses linking management of the Missouri River to population dynamics of Scaphirhynchus albus (pallid sturgeon)

Science.gov (United States)

Jacobson, Robert B.; Parsley, Michael J.; Annis, Mandy L.; Colvin, Michael E.; Welker, Timothy L.; James, Daniel A.

2016-01-20

This report documents a process of filtering of hypotheses that relate Missouri River Scaphirhynchus albus (pallid sturgeon) population dynamics to management actions including flow alterations, channel reconfigurations, and pallid sturgeon population augmentation. The filtering process was a partnership among U.S. Geological Survey, U.S. Army Corps of Engineers, and U.S. Fish and Wildlife Service to contribute to the Missouri River Recovery Management Plan process. The objective of the filtering process was to produce a set of hypotheses with high relevance to pallid sturgeon population dynamics and decision making on the Missouri River. The Missouri River Pallid Sturgeon Effects Analysis team filtered hundreds of potential hypotheses implicit in conceptual ecological models to develop a set of 40 candidate dominant hypotheses that were identified by experts as being important in pallid sturgeon population dynamics. Using a modified Delphi process and additional expert opinion, the team reduced this set of hypotheses to 23 working dominant hypotheses. We then matched the 23 hypotheses with management actions that could influence the biotic outcomes, resulting in as many as 176 potential effects between management actions and pallid sturgeon in the Missouri River. This number was consolidated to a candidate set of 53 working management hypotheses because some management actions applied to multiple life stages of the pallid sturgeon. We used an additional round of expert surveys to identify a set of 30 working management hypotheses. Finally, the set of working management hypotheses was filtered by the U.S. Army Corps of Engineers, Missouri River Recovery Program for actions that were within the agency’s authority and jurisdiction. This round resulted in a set of 21 hypotheses for initial modeling of linkages from management to pallid sturgeon population responses.

Conceptual Commitments of the LIDA Model of Cognition

Science.gov (United States)

Franklin, Stan; Strain, Steve; McCall, Ryan; Baars, Bernard

2013-06-01

Significant debate on fundamental issues remains in the subfields of cognitive science, including perception, memory, attention, action selection, learning, and others. Psychology, neuroscience, and artificial intelligence each contribute alternative and sometimes conflicting perspectives on the supervening problem of artificial general intelligence (AGI). Current efforts toward a broad-based, systems-level model of minds cannot await theoretical convergence in each of the relevant subfields. Such work therefore requires the formulation of tentative hypotheses, based on current knowledge, that serve to connect cognitive functions into a theoretical framework for the study of the mind. We term such hypotheses "conceptual commitments" and describe the hypotheses underlying one such model, the Learning Intelligent Distribution Agent (LIDA) Model. Our intention is to initiate a discussion among AGI researchers about which conceptual commitments are essential, or particularly useful, toward creating AGI agents.

Theoretical trajectories: Dreams and dreaming from Freud to Bion.

Science.gov (United States)

Vinocur Fischbein, Susana; Miramón, Beatriz

2015-08-01

This paper aims at comparing Freud's and Bion's conceptual models on dreams and dreaming. Beyond both authors' shared disposition vis-à-vis problems posed by knowledge, a critical gap opens regarding their differing clinical practices. It is hypothesized that their ideas do not belong to irreconcilable paradigms, but that there are continuities besides discontinuities more frequently highlighted between Freudian statements on psychic functioning--described in his theory on dreams--and Bion's findings in his development of both the original theory and the connections between dreaming and thinking. Firstly, Freud's and Bion's epistemological sources are examined as well as their creative use and historical environment. Then certain general theoretical and clinical issues are considered concerning their theories on dreams, the evolution of their ideas and corresponding clinical contexts. In a third section, their confluences and dissimilarities are dealt with, including clinical vignettes belonging to the authors to illustrate their interpretative modes of working. This is meant to show both an implicit theoretical-clinical complementarity and the fact that, though their routes bifurcate about the function of dreams, there remain connecting paths. Lastly, the final remarks review certain issues that have frequently been controversial between these lines of thought. Copyright © 2015 Institute of Psychoanalysis.

Assessing hypotheses about nesting site occupancy dynamics

Science.gov (United States)

Bled, Florent; Royle, J. Andrew; Cam, Emmanuelle

2011-01-01

Hypotheses about habitat selection developed in the evolutionary ecology framework assume that individuals, under some conditions, select breeding habitat based on expected fitness in different habitat. The relationship between habitat quality and fitness may be reflected by breeding success of individuals, which may in turn be used to assess habitat quality. Habitat quality may also be assessed via local density: if high-quality sites are preferentially used, high density may reflect high-quality habitat. Here we assessed whether site occupancy dynamics vary with site surrogates for habitat quality. We modeled nest site use probability in a seabird subcolony (the Black-legged Kittiwake, Rissa tridactyla) over a 20-year period. We estimated site persistence (an occupied site remains occupied from time t to t + 1) and colonization through two subprocesses: first colonization (site creation at the timescale of the study) and recolonization (a site is colonized again after being deserted). Our model explicitly incorporated site-specific and neighboring breeding success and conspecific density in the neighborhood. Our results provided evidence that reproductively "successful'' sites have a higher persistence probability than "unsuccessful'' ones. Analyses of site fidelity in marked birds and of survival probability showed that high site persistence predominantly reflects site fidelity, not immediate colonization by new owners after emigration or death of previous owners. There is a negative quadratic relationship between local density and persistence probability. First colonization probability decreases with density, whereas recolonization probability is constant. This highlights the importance of distinguishing initial colonization and recolonization to understand site occupancy. All dynamics varied positively with neighboring breeding success. We found evidence of a positive interaction between site-specific and neighboring breeding success. We addressed local

Corrigendum to: Bayesian evaluation of informative hypotheses in SEM using Mplus

NARCIS (Netherlands)

van de Schoot, R.; Verhoeven, Marjolein; Hoijtink, H.

2014-01-01

This paper corrects: van de Schoot, R., Verhoeven, M., & Hoijtink, H. (2013). Bayesian evaluation ofinformative hypotheses in SEM using Mplus: A black bear story. EuropeanJournal of Developmental Psychology, 10, 81 –98.

A Simple theoretical model for 63Ni betavoltaic battery

International Nuclear Information System (INIS)

ZUO, Guoping; ZHOU, Jianliang; KE, Guotu

2013-01-01

A numerical simulation of the energy deposition distribution in semiconductors is performed for 63 Ni beta particles. Results show that the energy deposition distribution exhibits an approximate exponential decay law. A simple theoretical model is developed for 63 Ni betavoltaic battery based on the distribution characteristics. The correctness of the model is validated by two literature experiments. Results show that the theoretical short-circuit current agrees well with the experimental results, and the open-circuit voltage deviates from the experimental results in terms of the influence of the PN junction defects and the simplification of the source. The theoretical model can be applied to 63 Ni and 147 Pm betavoltaic batteries. - Highlights: • The energy deposition distribution is found following an approximate exponential decay law when beta particles emitted from 63 Ni pass through a semiconductor. • A simple theoretical model for 63 Ni betavoltaic battery is constructed based on the exponential decay law. • Theoretical model can be applied to the betavoltaic batteries which radioactive source has a similar energy spectrum with 63 Ni, such as 147 Pm

Dynamics and stabilization of peak current-mode controlled buck converter with constant current load

International Nuclear Information System (INIS)

Leng Min-Rui; Zhou Guo-Hua; Zhang Kai-Tun; Li Zhen-Hua

2015-01-01

The discrete iterative map model of peak current-mode controlled buck converter with constant current load (CCL), containing the output voltage feedback and ramp compensation, is established in this paper. Based on this model the complex dynamics of this converter is investigated by analyzing bifurcation diagrams and the Lyapunov exponent spectrum. The effects of ramp compensation and output voltage feedback on the stability of the converter are investigated. Experimental results verify the simulation and theoretical analysis. The stability boundary and chaos boundary are obtained under the theoretical conditions of period-doubling bifurcation and border collision. It is found that there are four operation regions in the peak current-mode controlled buck converter with CCL due to period-doubling bifurcation and border-collision bifurcation. Research results indicate that ramp compensation can extend the stable operation range and transfer the operating mode, and output voltage feedback can eventually eliminate the coexisting fast-slow scale instability. (paper)

Deformational plagiocephaly in normal infants: a systematic review of causes and hypotheses.

Science.gov (United States)

De Bock, Freia; Braun, Volker; Renz-Polster, Herbert

2017-06-01

Deformational plagiocephaly (DP) is one of the most prevalent abnormal findings in infants and a frequent reason for parents to seek paediatric advice. To systematically review the literature and identify evidence and hypotheses on the aetiology and determinants of DP in otherwise healthy infants. Systematic keyword search in all major biomedical databases to identify peer-reviewed publications reporting (a) empirical research or (b) hypotheses on the aetiology of DP in healthy, term infants. 3150 studies published between 1985 and 2016 and containing relevant keywords were screened. In a two-pronged approach, results were summarised separately for the body of empirical work (22 studies) and the body of hypotheses (110 articles). Only a few empirical studies have examined risk factors in non-selected patient populations on a higher grade methodological level. The most commonly reported risk factors were: male gender, supine sleep position, limited neck rotation or preference in head position, first-born child, lower level of activity and lack of tummy time. Agreement between empirical studies was poor for most exposures, including supine sleep position, tummy time and use of car seats. The articles reporting hypotheses on the aetiology of DP cover a wide field of environmental and biological factors, but include little suggestions as to the potential influence of the everyday care environment of the baby. The evidence on the aetiology of DP is fragmentary and heterogeneous. In addition, factors possibly relevant to the development of DP have not been appreciated in the scientific discussion. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Controversial hypotheses on the relationship between researcher and informant in qualitative research.

Science.gov (United States)

Wilde, V

1992-02-01

This paper addresses methodological issues that emerged unexpectedly during a qualitative study set up to explore nurses' descriptions of difficult, challenging and satisfying experiences at work. The purpose of the study had been to look for critical factors influencing nurses' perceptions of their performance in specific situations, and their labelling of each event. Ten nurses were asked to describe in detail three events; a difficult situation in which they had coped well, a difficult situation in which they would like to have coped better, and a satisfying or rewarding situation. The critical incident technique was used. Rich descriptions were obtained, tape recorded, transcribed verbatum, and analysed by constant comparative analysis, following the principles of grounded theory. Some suprising hypotheses emerged regarding the methodology of the informal interview in qualitative research. This paper addresses these hypotheses, which focus on the interaction between the researcher and informant, the role conflict facing the nurse researcher, the effect of the researcher's past experience on the interaction, the use of counselling strategies and the principle of self-disclosure. These hypotheses were incidental to the original area of study and were more exciting in their emergence because of this.

Estimating the Proportion of True Null Hypotheses in Multiple Testing Problems

Directory of Open Access Journals (Sweden)

Oluyemi Oyeniran

2016-01-01

Full Text Available The problem of estimating the proportion, π0, of the true null hypotheses in a multiple testing problem is important in cases where large scale parallel hypotheses tests are performed independently. While the problem is a quantity of interest in its own right in applications, the estimate of π0 can be used for assessing or controlling an overall false discovery rate. In this article, we develop an innovative nonparametric maximum likelihood approach to estimate π0. The nonparametric likelihood is proposed to be restricted to multinomial models and an EM algorithm is also developed to approximate the estimate of π0. Simulation studies show that the proposed method outperforms other existing methods. Using experimental microarray datasets, we demonstrate that the new method provides satisfactory estimate in practice.

Theoretical Approaches in Evolutionary Ecology: Environmental Feedback as a Unifying Perspective.

Science.gov (United States)

Lion, Sébastien

2018-01-01

Evolutionary biology and ecology have a strong theoretical underpinning, and this has fostered a variety of modeling approaches. A major challenge of this theoretical work has been to unravel the tangled feedback loop between ecology and evolution. This has prompted the development of two main classes of models. While quantitative genetics models jointly consider the ecological and evolutionary dynamics of a focal population, a separation of timescales between ecology and evolution is assumed by evolutionary game theory, adaptive dynamics, and inclusive fitness theory. As a result, theoretical evolutionary ecology tends to be divided among different schools of thought, with different toolboxes and motivations. My aim in this synthesis is to highlight the connections between these different approaches and clarify the current state of theory in evolutionary ecology. Central to this approach is to make explicit the dependence on environmental dynamics of the population and evolutionary dynamics, thereby materializing the eco-evolutionary feedback loop. This perspective sheds light on the interplay between environmental feedback and the timescales of ecological and evolutionary processes. I conclude by discussing some potential extensions and challenges to our current theoretical understanding of eco-evolutionary dynamics.

Recruitment processes in Baltic sprat - A re-evaluation of GLOBEC Germany hypotheses

Science.gov (United States)

Voss, Rüdiger; Peck, Myron A.; Hinrichsen, Hans-Harald; Clemmesen, Catriona; Baumann, Hannes; Stepputtis, Daniel; Bernreuther, Matthias; Schmidt, Jörn O.; Temming, Axel; Köster, Fritz W.

2012-12-01

The GLOBEC Germany program (2002-2007) had the ambitious goal to resolve the processes impacting the recruitment dynamics of Baltic sprat (Sprattus sprattus L.) by examining various factors affecting early life history stages. At the start of the research program, a number of general recruitment hypotheses were formulated, i.e. focusing on (1) predation, (2) food availability, (3) physical parameters, (4) the impact of current systems, and finally (5) the importance of top-down vs bottom-up effects. The present study synthesizes the results of field sampling (2002 and 2003), laboratory experiments, and modeling studies to re-evaluate these hypotheses for the Baltic sprat stock. Recruitment success was quite different in the 2 years investigated. Despite a lower spawning stock biomass in 2003, the total number of recruits was almost 2-fold higher that year compared to 2002. The higher recruitment success in 2003 could be attributed to enhanced survival success during the post-larval/juvenile stage, a life phase that appears to be critical for recruitment dynamics. In the state of the Baltic ecosystem during the period of investigation, we consider bottom-up control (e.g. temperature, prey abundance) to be more important than top-down control (predation mortality). This ranking in importance does not vary seasonally. Prevailing water circulation patterns and the transport dynamics of larval cohorts have a strong influence on sprat recruitment success. Pronounced transport to coastal areas is detrimental for year-class strength particularly at high sprat stock sizes. A suggested mechanism is density-dependant regulation of survival via intra- and inter-specific competition for prey in coastal areas. A documented change in larval vertical migration behavior between the early 1990s and early 2000s increased the transport potential to the coast, strengthening the coupling between inter-annual differences in the magnitude and direction of wind-driven surface currents and

Eddy currents in pulsed field measurements

International Nuclear Information System (INIS)

Kuepferling, M.; Groessinger, R.; Wimmer, A.; Taraba, M.; Scholz, W.

2002-01-01

Full text: One problem of pulsed field magnetometry is an error in magnetization, which appears in measurements of conducting samples. This error is due to eddy currents induced by a time varying field. To allow predictions how eddy currents exert influence on the hysteresis loop, systematic experimental and theoretical studies of pulsed field measurements of metallic samples were performed. The theoretical studies include analytical calculations as well as numerical ones using a 2D finite element software. In the measurements three physical parameters have been varied: i) the conductivity of the sample by using two different materials, in this case technical Cu and Al ii) size and shape of the sample by using cylinders, spheres and cuboids iii) the pulse duration of the external field by changing the capacitor battery from 8mF ( =9.1ms) to 24mF ( =15.7ms). The time dependence of the external field corresponds with a pulsed damped harmonic oscillation with a maximum value of 5.2T. The samples were studied in the as cast state (after machining) as well as after heat treatment. Theoretical calculations showed not only good agreement with the absolute values of the measured eddy current m agnetization , they also gave an explanation of the shape of the eddy current hysteresis and the dependence of the eddy current 'magnetization' on parameters as pulse duration of the external field and conductivity of the sample. (author)

Current Capability of Atomic Structure Theory

International Nuclear Information System (INIS)

Kim, Yong Ki

1993-01-01

Current capability of atomic structure theory is reviewed, and advantages, disadvantages and major features of popular atomic structure codes described. Comparisons between theoretical and experimental data on transition energies and lifetimes of excited levels are presented to illustrate the current capability of atomic structure codes.

Early Stuttering, Temperament and Anxiety: Two Hypotheses

Science.gov (United States)

Kefalianos, Elaina; Onslow, Mark; Block, Susan; Menzies, Ross; Reilly, Sheena

2012-01-01

Purpose: The topic of temperament and early stuttering and the extent to which it involves anxiety is theoretically and clinically relevant. The topic can contribute to theory development and clinical practices with early stuttering. Method: We present a review of the empirical literature for this area with a view to determining which of two…

Support for major hypotheses in invasion biology is uneven and declining

Czech Academy of Sciences Publication Activity Database

Jeschke, J.M.; Aparicio, L.G.; Haider, S.; Heger, T.; Lortie, C. J.; Pyšek, Petr; Strayer, D.L.

2012-01-01

Roč. 2012, č. 14 (2012), s. 1-20 ISSN 1619-0033 R&D Projects: GA ČR(CZ) GAP504/11/1028 Institutional support: RVO:67985939 Keywords : biological invasions * hypotheses * testing Subject RIV: EF - Botanics

Development of DSM-V and ICD-11: tendencies and potential of new classifications in psychiatry at the current state of knowledge.

Science.gov (United States)

Möller, Hans-Jürgen

2009-10-01

A reason for the necessity to revise ICD-10 and DSM-IV is the increase of knowledge in the past 20 years, especially neurobiological knowledge. But is this increase of knowledge, for example in the field of neurogenetics, of such magnitude that a revision of the psychiatric classification is necessary and promises to be fruitful? The current plans for DSM-V or ICD-11, respectively, focus on different improvements. In this context also the introduction of a purely syndromatic/dimensional approach without including etiopathogenetic hypotheses, is discussed. A switch to such a dimensional approach, which was discussed among others in the DSM-V task force Deconstructing Psychosis, would be the most radical development. It could avoid many theoretical pre-assumptions about causal hypotheses, which are still associated with ICD-10 and DSM-IV. This would indeed increase the validity of psychiatric classification, but it would also reduce the information as compared to traditional diagnostic categories with all the current implications concerning etiopathogenesis, therapy and prognosis. Such a dimensional approach would also mean that the syndromes would have to be assessed in a standardized way for each person seeking help from the psychiatric service system or for each person undergoing psychiatric research. This would have to be a multi-dimensional assessment covering all syndromes existing within different psychiatric disorders. Based on the different aspects that must be considered in this context, a careful revision seems more advisable than a radical change of classification.

Theoretical analyses of superconductivity in iron based ...

African Journals Online (AJOL)

This paper focuses on the theoretical analysis of superconductivity in iron based superconductor Ba1−xKxFe2As2. After reviewing the current findings on this system, we suggest that phononexciton combined mechanism gives a right order of superconducting transition temperature (TC) for Ba1−xKxFe2As2 . By developing ...

The First Galaxies Theoretical Predictions and Observational Clues

CERN Document Server

Mobasher, Bahram; Bromm, Volker

2013-01-01

New observations of the period between the cosmic recombination and the end of reionization are posing intriguing questions about where the first generations of stars were formed, how the first galaxies were assembled, whether these galaxies have low redshift counterparts, and what role the early galaxies played in the reionization process. Combining the new observational data with theoretical models can shed new light on open issues regarding the star formation process, its role in the reionization of the Universe, and the metal enrichment in galaxies at those early epochs. This volume brings together leading experts in the field to discuss our current level of understanding and what may come in the near future as our observational as well as theoretical tools improve. The book confronts the theory of how the first stars, black holes, and galaxies formed with current and planned observations. This synthesis is very timely, just ahead of the establishment of major new facilities, such as the James Webb Space ...

Serial Learning Process: Test of Chaining, Position, and Dual-Process Hypotheses

Science.gov (United States)

Giurintano, S. L.

1973-01-01

The chaining, position, and dual-process hypotheses of serial learning (SL) as well as serial recall, reordering, and relearning of paired-associate learning were examined to establish learning patterns. Results provide evidence for dual-process hypothesis. (DS)

Ground Return Current Behaviour in High Voltage Alternating Current Insulated Cables

Directory of Open Access Journals (Sweden)

Roberto Benato

2014-12-01

Full Text Available The knowledge of ground return current in fault occurrence plays a key role in the dimensioning of the earthing grid of substations and of cable sealing end compounds, in the computation of rise of earth potential at substation sites and in electromagnetic interference (EMI on neighbouring parallel metallic conductors (pipes, handrails, etc.. Moreover, the ground return current evaluation is also important in steady-state regime since this stray current can be responsible for EMI and also for alternating current (AC corrosion. In fault situations and under some assumptions, the ground return current value at a substation site can be computed by means of k-factors. The paper shows that these simplified and approximated approaches have a lot of limitations and only multiconductor analysis can show the ground return current behaviour along the cable (not only the two end values both in steady-state regime and in short circuit occurrence (e.g., phase-to-ground and phase-to-phase-to-ground. Multiconductor cell analysis (MCA considers the cable system in its real asymmetry without simplified and approximated hypotheses. The sensitivity of ground return current on circuit parameters (cross-bonding box resistances, substation earthing resistances, soil resistivity is presented in the paper.

Skin Stem Cell Hypotheses and Long Term Clone Survival - Explored Using Agent-based Modelling

OpenAIRE

Li, X.; Upadhyay, A.K.; Bullock, A.J.; Dicolandrea, T.; Xu, J.; Binder, R.L.; Robinson, M.K.; Finlay, D.R.; Mills, K.J.; Bascom, C.C.; Kelling, C.K.; Isfort, R.J.; Haycock, J.W.; MacNeil, S.; Smallwood, R.H.

2013-01-01

Epithelial renewal in skin is achieved by the constant turnover and differentiation of keratinocytes. Three popular hypotheses have been proposed to explain basal keratinocyte regeneration and epidermal homeostasis: 1) asymmetric division (stem-transit amplifying cell); 2) populational asymmetry (progenitor cell with stochastic fate); and 3) populational asymmetry with stem cells. In this study, we investigated lineage dynamics using these hypotheses with a 3D agent-based model of the epiderm...

ACCOUNTING AND AUDIT OPERATIONS ON CURRENT ACCOUNT

Directory of Open Access Journals (Sweden)

Koblyanska Olena

2018-03-01

Full Text Available Introduction. The article is devoted to theoretical, methodical and practical issues of accounting and auditing of operations on the current account. The purpose of the study is to deepen and consolidate the theoretical and practical knowledge of the issues of accounting and auditing of operations on the current account, identify practical problems with the implementation of the methodology and organization of accounting and auditing of operations on the current account and develop recommendations for the elimination of deficiencies and improve the accounting and auditing. Results. The issue of the relevance of proper accounting and audit of transactions on the current account in the bank is considered. The research of typical operations on the current account was carried out with using of the method of their reflection in the account on practical examples. Features of the audit of transactions on the current account are examined, the procedure for its implementation is presented, and types of abuses and violations that occur while performing operations on the current account are identified. The legal regulation of accounting, analysis and control of operations with cash on current accounts is considered. The problem issues related to the organization and conducting of the audit of funds in the accounts of the bank are analyzed, as well as the directions of their solution are determined. The proposals for determining the sequence of actions of the auditor during the check of cash flow on accounts in the bank are provided. Conclusions. The questions about theoretical, methodological and practical issues of accounting and auditing of operations on the current account in the bank. A study of typical operations with cash on the current account was carried out with the use of the method of their reflection in the accounts and the features of the auditing of cash on the account.

Vestigial Biological Structures: A Classroom-Applicable Test of Creationist Hypotheses

Science.gov (United States)

Senter, Phil; Ambrocio, Zenis; Andrade, Julia B.; Foust, Katanya K.; Gaston, Jasmine E.; Lewis, Ryshonda P.; Liniewski, Rachel M.; Ragin, Bobby A.; Robinson, Khanna L.; Stanley, Shane G.

2015-01-01

Lists of vestigial biological structures in biology textbooks are so short that some young-Earth creationist authors claim that scientists have lost confidence in the existence of vestigial structures and can no longer identify any verifiable ones. We tested these hypotheses with a method that is easily adapted to biology classes. We used online…

Theoretical rationale for music selection in oncology intervention research: an integrative review.

Science.gov (United States)

Burns, Debra S

2012-01-01

Music-based interventions have helped patients with cancer improve their quality of life, decrease treatment related distress, and manage pain. However, quantitative findings from music intervention studies are inconsistent. The purpose of this review was to explore the theoretical underpinnings for the selection of the music stimuli used to influence targeted outcomes. It was hypothesized that disparate findings were due in part to the atheoretical nature of music selection and the resulting diversity in music stimuli between and within studies. A systematic research synthesis including a comprehensive database and reference list search resulted in 22 studies. Included studies were compiled into two tables cataloging intervention theory, intervention content, and outcomes. A majority of studies did not provide a rationale or intervention theory for the delivery of music or choice of outcomes. Recorded music was the most common delivery method, but the specific music was rarely included within the report. Only two studies that included a theoretical framework reported null results on at least some of the outcomes. Null results are partially explained by an incomplete or mismatch in intervention theory and music selection and delivery. While the inclusion of an intervention theory does not guarantee positive results, including a theoretical rationale for the use of music, particular therapeutic processes or mechanisms, and the specifics of how music is selected and delivered increases scientific rigor and the probability of clinical translation.

Political Participation Online: The Replacement and the Mobilisation Hypotheses Revisited

DEFF Research Database (Denmark)

Jensen, Jakob Linaa

2013-01-01

This article discusses the state of political participation online more than ten years after the Internet’s great popular breakthrough as an everyday medium. Denmark is used as a case study to critically re-examine the frequently discussed replacement and mobilisation hypotheses on behalf of the ...... participation, efficacy and social capital seem to have less impact on online political participation. In the end, these findings are related to more overall discussions on the democratising potential of the Internet.......This article discusses the state of political participation online more than ten years after the Internet’s great popular breakthrough as an everyday medium. Denmark is used as a case study to critically re-examine the frequently discussed replacement and mobilisation hypotheses on behalf...... of the Internet. The pure replacement hypothesis is rejected. Instead, it is found that the Internet still supplements rather than replaces other media, even among heavy Internet users. The Internet is one among several media used by ‘media omnivores’, and political participation online supplements rather than...

Theoretical Model of Development of Information Competence among Students Enrolled in Elective Courses

Science.gov (United States)

Zhumasheva, Anara; Zhumabaeva, Zaida; Sakenov, Janat; Vedilina, Yelena; Zhaxylykova, Nuriya; Sekenova, Balkumis

2016-01-01

The current study focuses on the research topic of creating a theoretical model of development of information competence among students enrolled in elective courses. In order to examine specific features of the theoretical model of development of information competence among students enrolled in elective courses, we performed an analysis of…

Transitionality in addiction: A "temporal continuum" hypotheses involving the aberrant motivation, the hedonic dysregulation, and the aberrant learning.

Science.gov (United States)

Patrono, Enrico; Gasbarri, Antonella; Tomaz, Carlos; Nishijo, Hisao

2016-08-01

Addiction is a chronic compulsion and relapsing disorder. It involves several brain areas and circuits, which encode vary functions such as reward, motivation, and memory. Drug addiction is defined as a "pathological pattern of use of a substance", characterized by the loss of control on drug-taking-related behaviors, the pursuance of those behaviors even in the presence of negative consequences, and a strong motivated activity to assume substances. Three different theories guide experimental research on drug addiction. Each of these theories consider singles features, such as an aberrant motivation, a hedonic dysregulation, and an aberrant habit learning as the main actor to explain the entire process of the addictive behaviors. The major goal of this study is to present a new hypotheses of transitionality from a controlled use to abuse of addictive substances trough the overview of the three different theories, considering all the single features of each single theory together on the same "temporal continuum" from use to abuse of addictive substances. Recently, it has been suggested that common neural systems may be activated by natural and pharmacological stimuli, raising the hypotheses that binge-eating disorders could be considered as addictive behaviors. The second goal of this study is to present evidences in order to highlight a possible psycho-bio-physiological superimposition between drug and "food addiction". Finally, interesting questions are brought up starting from last findings about a theoretical/psycho-bio-physiological superimposition between drug and "food addiction" and their possibly same transitionality along the same "temporal continuum" from use to abuse of addictive substances in order to investigate new therapeutic strategies based on new therapeutic strategies based on the individual moments characterizing the transition from the voluntary intake of substances to the maladaptive addictive behavior. Copyright © 2016. Published by Elsevier

Dream-reality confusion in Borderline Personality Disorder: A theoretical analysis

Directory of Open Access Journals (Sweden)

Dagna eSkrzypińska

2015-09-01

Full Text Available This paper presents an analysis of dream-reality confusion (DRC in relation to the characteristics of borderline personality disorder (BPD, based on research findings and theoretical considerations. It is hypothesized that people with BPD are more likely to experience DRC compared to people in non-clinical population. Several variables related to this hypothesis were identified through a theoretical analysis of the scientific literature. Sleep disturbances: Problems with sleep are found in 15-95.5% of people with BPD (Hafizi, 2013, and unstable sleep and wake cycles, which occur in BPD (Fleischer et al., 2012, are linked to DRC. Dissociation: Nearly two-thirds of people with BPD experience dissociative symptoms (Korzekwa and Pain, 2009 and dissociative symptoms are correlated with a fantasy proneness; both dissociative symptoms and fantasy proneness are related to DRC (Giesbrecht and Merckelbach, 2006. Negative dream content: People with BPD have nightmares more often than other people (Semiz et al., 2008; dreams that are more likely to be confused with reality tend to be more realistic and unpleasant, and are reflected in waking behavior (Rassin et al., 2001. Cognitive disturbances: Many BPD patients experience various cognitive disturbances, including problems with reality testing (Fiqueierdo, 2006; Mosquera et al., 2011, which can foster DRC. Thin boundaries: People with thin boundaries are more prone to DRC than people with thick boundaries, and people with BPD tend to have thin boundaries (Hartmann, 2011. The theoretical analysis on the basis of these findings suggests that people who suffer from BPD may be more susceptible to confusing dream content with actual waking events.

A thermodynamic and theoretical view for enzyme regulation.

Science.gov (United States)

Zhao, Qinyi

2015-01-01

Precise regulation is fundamental to the proper functioning of enzymes in a cell. Current opinions about this, such as allosteric regulation and dynamic contribution to enzyme regulation, are experimental models and substantially empirical. Here we proposed a theoretical and thermodynamic model of enzyme regulation. The main idea is that enzyme regulation is processed via the regulation of abundance of active conformation in the reaction buffer. The theoretical foundation, experimental evidence, and experimental criteria to test our model are discussed and reviewed. We conclude that basic principles of enzyme regulation are laws of protein thermodynamics and it can be analyzed using the concept of distribution curve of active conformations of enzymes.

Causal null hypotheses of sustained treatment strategies: What can be tested with an instrumental variable?

Science.gov (United States)

Swanson, Sonja A; Labrecque, Jeremy; Hernán, Miguel A

2018-05-02

Sometimes instrumental variable methods are used to test whether a causal effect is null rather than to estimate the magnitude of a causal effect. However, when instrumental variable methods are applied to time-varying exposures, as in many Mendelian randomization studies, it is unclear what causal null hypothesis is tested. Here, we consider different versions of causal null hypotheses for time-varying exposures, show that the instrumental variable conditions alone are insufficient to test some of them, and describe additional assumptions that can be made to test a wider range of causal null hypotheses, including both sharp and average causal null hypotheses. Implications for interpretation and reporting of instrumental variable results are discussed.

Phenomenology of neutral current interactions

International Nuclear Information System (INIS)

Sakurai, J.J.

1978-01-01

Neutral-current interactions are discussed within a rather general phenomenological framework without commitment to any particular theoretical model. Three points are kept in mind: what various experiments really measure; the performing of complete experiments to determine the neutral-current couplings; and the testing of models in an objective, emotionally uninvolved manner. The following topics are considered: neutrino-electron scattering, hadronic currents and models, neutrino-induced inclusive hadronic reactions, neutrino-induced exclusive hadronic reactions, and neutral-current phenomena without neutrinos. In conclusion, what has actually been learned about neutral-current interactions is summarized. 9 figures, 2 tables

Emerging theoretical understanding of pluricentric coordination in public governance

DEFF Research Database (Denmark)

Reff Pedersen, Anne; Sehested, Karina; Sørensen, Eva

2011-01-01

Currently, we are witnessing a comprehensive change in the theoretical understandings of how coordination is provided in the pursuit of public governance. Traditional strands of theory took their departure from the presumption that coordination is the outcome of processes within coherent institut...

Double Exponential Relativity Theory Coupled Theoretically with Quantum Theory?

International Nuclear Information System (INIS)

Montero Garcia, Jose de la Luz; Novoa Blanco, Jesus Francisco

2007-01-01

Here the problem of special relativity is analyzed into the context of a new theoretical formulation: the Double Exponential Theory of Special Relativity with respect to which the current Special or Restricted Theory of Relativity (STR) turns to be a particular case only

Global changes of climate through human activities. New clues and hypotheses

Energy Technology Data Exchange (ETDEWEB)

Grassl, H

1988-02-01

New clues to world-wide changes of climate through human activities have been found or corroborated: Precipitation belts have shifted during the last 30 years; ozone over Antarctica in spring has fallen to its lowest level ever (1956); near-ground ozone in our latitudes has at least doubled in this century. Newly discussed hypotheses are: The oxidation capacity and, consequently, the purification capacity of the atmosphere decreases in the southern hemisphere owing above all to the increase in methane. Increased backscatter of solar radiation through low clouds during periods of turbid air in the atmosphere attenuates the greenhouse effect, the increase in icy clouds through condensation trails of jets flying at high altitudes intensifies the greenhouse effect of the atmosphere. The paper analyses these hypotheses and shows that the distinction between change of climate on the one hand and ecological damage on the other is not justifiable any longer. (orig./HSCH).

Using potential performance theory to test five hypotheses about meta-attribution.

Science.gov (United States)

Trafimow, David; Hunt, Gayle; Rice, Stephen; Geels, Kasha

2011-01-01

Based on I. Kant's (1991) distinction between perfect and imperfect duties and the attribution literature pertaining to that distinction, the authors proposed and tested 5 hypotheses about meta-attribution. More specifically, violations of perfect duties have been shown to arouse both more negative affect and stronger correspondent inferences than do violations of imperfect duties (e.g., D. Trafimow, I. K. Bromgard, K. A. Finlay, & T. Ketelaar, 2005). But when it comes to making meta-attributions-that is, guessing the attributions others would make-is the affect differential an advantage or a disadvantage? In addition to the null hypothesis of no effect, the authors proposed and tested additional hypotheses about how negative affect might increase or decrease the effectiveness of people's meta-attribution strategies and how even if there is no effect on strategy effectiveness, negative affect could increase or decrease the consistencies with which these strategies could be used.

PRICE DISCRIMINATION AND MARKET POWER: A THEORETICAL ANALYSIS

Directory of Open Access Journals (Sweden)

Olga Smirnova

2015-07-01

Full Text Available This paper analyzes the contemporary theoretical and empirical research in the field of impact assessment of market power and conclusions about the possibilities of the company to implement price discrimination in different market structures. The results of the analysis allow to evaluate current approaches to antitrust regulation of price discrimination.

Bayes Factor Approaches for Testing Interval Null Hypotheses

NARCIS (Netherlands)

Morey, Richard D.; Rouder, Jeffrey N.

2011-01-01

Psychological theories are statements of constraint. The role of hypothesis testing in psychology is to test whether specific theoretical constraints hold in data. Bayesian statistics is well suited to the task of finding supporting evidence for constraint, because it allows for comparing evidence

Host Lipid Mediators in Leprosy: The Hypothesized Contributions to Pathogenesis

Directory of Open Access Journals (Sweden)

Carlos A. M. Silva

2018-02-01

Full Text Available The spectrum of clinical forms observed in leprosy and its pathogenesis are dictated by the host’s immune response against Mycobacterium leprae, the etiological agent of leprosy. Previous results, based on metabolomics studies, demonstrated a strong relationship between clinical manifestations of leprosy and alterations in the metabolism of ω3 and ω6 polyunsaturated fatty acids (PUFAs, and the diverse set of lipid mediators derived from PUFAs. PUFA-derived lipid mediators provide multiple functions during acute inflammation, and some lipid mediators are able to induce both pro- and anti-inflammatory responses as determined by the cell surface receptors being expressed, as well as the cell type expressing the receptors. However, little is known about how these compounds influence cellular immune activities during chronic granulomatous infectious diseases, such as leprosy. Current evidence suggests that specialized pro-resolving lipid mediators (SPMs are involved in the down-modulation of the innate and adaptive immune response against M. leprae and that alteration in the homeostasis of pro-inflammatory lipid mediators versus SPMs is associated with dramatic shifts in the pathogenesis of leprosy. In this review, we discuss the possible consequences and present new hypotheses for the involvement of ω3 and ω6 PUFA metabolism in the pathogenesis of leprosy. A specific emphasis is placed on developing models of lipid mediator interactions with the innate and adaptive immune responses and the influence of these interactions on the outcome of leprosy.

Interactive 3D visualization for theoretical virtual observatories

Science.gov (United States)

Dykes, T.; Hassan, A.; Gheller, C.; Croton, D.; Krokos, M.

2018-06-01

Virtual observatories (VOs) are online hubs of scientific knowledge. They encompass a collection of platforms dedicated to the storage and dissemination of astronomical data, from simple data archives to e-research platforms offering advanced tools for data exploration and analysis. Whilst the more mature platforms within VOs primarily serve the observational community, there are also services fulfilling a similar role for theoretical data. Scientific visualization can be an effective tool for analysis and exploration of data sets made accessible through web platforms for theoretical data, which often contain spatial dimensions and properties inherently suitable for visualization via e.g. mock imaging in 2D or volume rendering in 3D. We analyse the current state of 3D visualization for big theoretical astronomical data sets through scientific web portals and virtual observatory services. We discuss some of the challenges for interactive 3D visualization and how it can augment the workflow of users in a virtual observatory context. Finally we showcase a lightweight client-server visualization tool for particle-based data sets, allowing quantitative visualization via data filtering, highlighting two example use cases within the Theoretical Astrophysical Observatory.

Experimental and theoretical study of magnetohydrodynamic ship models.

Science.gov (United States)

Cébron, David; Viroulet, Sylvain; Vidal, Jérémie; Masson, Jean-Paul; Viroulet, Philippe

2017-01-01

Magnetohydrodynamic (MHD) ships represent a clear demonstration of the Lorentz force in fluids, which explains the number of students practicals or exercises described on the web. However, the related literature is rather specific and no complete comparison between theory and typical small scale experiments is currently available. This work provides, in a self-consistent framework, a detailed presentation of the relevant theoretical equations for small MHD ships and experimental measurements for future benchmarks. Theoretical results of the literature are adapted to these simple battery/magnets powered ships moving on salt water. Comparison between theory and experiments are performed to validate each theoretical step such as the Tafel and the Kohlrausch laws, or the predicted ship speed. A successful agreement is obtained without any adjustable parameter. Finally, based on these results, an optimal design is then deduced from the theory. Therefore this work provides a solid theoretical and experimental ground for small scale MHD ships, by presenting in detail several approximations and how they affect the boat efficiency. Moreover, the theory is general enough to be adapted to other contexts, such as large scale ships or industrial flow measurement techniques.

Experimental and theoretical study of magnetohydrodynamic ship models.

Directory of Open Access Journals (Sweden)

David Cébron

Full Text Available Magnetohydrodynamic (MHD ships represent a clear demonstration of the Lorentz force in fluids, which explains the number of students practicals or exercises described on the web. However, the related literature is rather specific and no complete comparison between theory and typical small scale experiments is currently available. This work provides, in a self-consistent framework, a detailed presentation of the relevant theoretical equations for small MHD ships and experimental measurements for future benchmarks. Theoretical results of the literature are adapted to these simple battery/magnets powered ships moving on salt water. Comparison between theory and experiments are performed to validate each theoretical step such as the Tafel and the Kohlrausch laws, or the predicted ship speed. A successful agreement is obtained without any adjustable parameter. Finally, based on these results, an optimal design is then deduced from the theory. Therefore this work provides a solid theoretical and experimental ground for small scale MHD ships, by presenting in detail several approximations and how they affect the boat efficiency. Moreover, the theory is general enough to be adapted to other contexts, such as large scale ships or industrial flow measurement techniques.

Interactive 3D Visualization for Theoretical Virtual Observatories

Science.gov (United States)

Dykes, Tim; Hassan, A.; Gheller, C.; Croton, D.; Krokos, M.

2018-04-01

Virtual Observatories (VOs) are online hubs of scientific knowledge. They encompass a collection of platforms dedicated to the storage and dissemination of astronomical data, from simple data archives to e-research platforms offering advanced tools for data exploration and analysis. Whilst the more mature platforms within VOs primarily serve the observational community, there are also services fulfilling a similar role for theoretical data. Scientific visualization can be an effective tool for analysis and exploration of datasets made accessible through web platforms for theoretical data, which often contain spatial dimensions and properties inherently suitable for visualization via e.g. mock imaging in 2d or volume rendering in 3d. We analyze the current state of 3d visualization for big theoretical astronomical datasets through scientific web portals and virtual observatory services. We discuss some of the challenges for interactive 3d visualization and how it can augment the workflow of users in a virtual observatory context. Finally we showcase a lightweight client-server visualization tool for particle-based datasets allowing quantitative visualization via data filtering, highlighting two example use cases within the Theoretical Astrophysical Observatory.

INFLUENCES ON AND FROM THE SEGMENTATION OF NETWORKS - HYPOTHESES AND TESTS

NARCIS (Netherlands)

BAERVELDT, C; SNIJDERS, T

This article discusses (a) the influence of network structure on the diffusion of (new) cultural behavior within the network and (b) the influence of external events, especially of social programs, on the diffusion of (new) cultural behavior, and on the network structure. Hypotheses are formulated

Theoretical studies of combustion dynamics

Energy Technology Data Exchange (ETDEWEB)

Bowman, J.M. [Emory Univ., Atlanta, GA (United States)

1993-12-01

The basic objectives of this research program are to develop and apply theoretical techniques to fundamental dynamical processes of importance in gas-phase combustion. There are two major areas currently supported by this grant. One is reactive scattering of diatom-diatom systems, and the other is the dynamics of complex formation and decay based on L{sup 2} methods. In all of these studies, the authors focus on systems that are of interest experimentally, and for which potential energy surfaces based, at least in part, on ab initio calculations are available.

A theoretical limit on the Higgs mass

International Nuclear Information System (INIS)

Temiraliev, A.T.

2007-01-01

Full text: The standard model of particle physics, which describes masses through the Higgs mechanism, contains parameters - such as particle masses - whose origins are still unknown and which cannot be exactly predicted, but whose values are constrained through their interactions. In particular, the masses of the top quark and W boson constrain the mass of the long-hypothesized, but thus far not observed, Higgs boson. Several more or less precise arguments can set the upper limit for a standard model Higgs particle. All of them follows the line that the standard model breaks down of the Higgs mass is pushed too far upwards. The theoretical bounds will be reviewed. With gauge-top quark Yukawa coupling unification the standard model Higgs boson mass is estimated to be about 135 GeV. In the article will be consider an approximation of 4-fermion interactions. And as a result, the most likely Higgs mass is 150 GeV. The upper limit on the Higgs mass at the 90 % confidence level is about 250 GeV

Hypotheses about geoglyphs at Nasca, Peru: new discoveries

Directory of Open Access Journals (Sweden)

Jaroslav Klokočník

2016-07-01

Full Text Available The known hypotheses about the reasons why the geoglyphs in the Nasca and Palpa region of Peru were created are many: roads/paths, rituals/ceremonials, use of hallucinogens, astronomical meaning, influence of extraterrestrials, underground water… and so on. We present a new hypothesis, formulated by J. Sonnek (first published in 2011 in the context of all previous hypotheses.1 Sonnek explains the geoglyphs as tidied work areas for the production of rope and nets, although he goes much further than Stierlin. This eccentric hypothesis now has not only experimental but also archaeological and ethnographical support, which is presented here. Geoglyphs of a special shape were discovered in the pampas; they may represent technical objects – different types of ‘rope twisters’. Following this idea, Sonnek made technical devices (using today’s materials and tested them in practice; they work perfectly, see his YouTube videos.2 In November 2012, wooden pieces, which may be the remnants of ropemaking, were collected from the pampa near the towns of Nasca and Palpa, in vicinity of these hypothetic ropemaking places. Radiocarbon testing by 14C standardized radio-carbon age according to Stuiver-Polach convention and Accelerator Mass Spectroscopy (AMS of these wood pieces shows the age to be in a wide range from Early Nasca to the 17th century (and to our epoch with a fake geoglyph, too, thus supporting (but surely not proving the new hypothesis. Moreover, in the Quechua language, the word huasca, waskha (read: uasca means a rope or cord or place where these are produced. This word is very similar to ‘nasca’.

Experienced physicians benefit from analyzing initial diagnostic hypotheses

Directory of Open Access Journals (Sweden)

Adam Bass

2013-03-01

Full Text Available Background: Most incorrect diagnoses involve at least one cognitive error, of which premature closure is the most prevalent. While metacognitive strategies can mitigate premature closure in inexperienced learners, these are rarely studied in experienced physicians. Our objective here was to evaluate the effect of analytic information processing on diagnostic performance of nephrologists and nephrology residents. Methods: We asked nine nephrologists and six nephrology residents at the University of Calgary and Glasgow University to diagnose ten nephrology cases. We provided presenting features along with contextual information, after which we asked for an initial diagnosis. We then primed participants to use either hypothetico-deductive reasoning or scheme-inductive reasoning to analyze the remaining case data and generate a final diagnosis. Results: After analyzing initial hypotheses, both nephrologists and residents improved the accuracy of final diagnoses (31.1% vs. 65.6%, p < 0.001, and 40.0% vs. 70.0%, p < 0.001, respectively. We found a significant interaction between experience and analytic processing strategy (p = 0.002: nephrology residents had significantly increased odds of diagnostic success when using scheme-inductive reasoning (odds ratio [95% confidence interval] 5.69 [1.59, 20.33], p = 0.007, whereas the performance of experienced nephrologists did not differ between strategies (odds ratio 0.57 [0.23, 1.39], p = 0.2. Discussion: Experienced nephrologists and nephrology residents can improve their performance by analyzing initial diagnostic hypotheses. The explanation of the interaction between experience and the effect of different reasoning strategies is unclear, but may relate to preferences in reasoning strategy, or the changes in knowledge structure with experience.

Current issues in electromagnetic knockout reactions

International Nuclear Information System (INIS)

Giusti, C.

2002-01-01

The role of correlations and two-body currents in one-nucleon emission reactions induced by an electromagnetic probe is discussed. The theoretical framework for cross section calculations is outlined and some results are presented for the exclusive "1"6O(e,e'p) "1"5N and "1"6O(γ, p) "1"5N reactions in relativistic and nonrelativistic models. A reliable and consistent evaluation of different types of correlations is needed to determine the spectroscopic factors. A consistent description of (e,e'p) and (γ, p) data, with the same spectroscopic factors, can be obtained when meson-exchange currents (MEC) are included in the theoretical model. MEC give an important contribution to (γ, p) cross sections and have only a small effect in (e, e'p). In the relativistic model the two-body seagull current affects the calculated cross sections less than in the nonrelativistic calculations.

On precipitation monitoring with theoretical statistical distributions

Science.gov (United States)

Cindrić, Ksenija; Juras, Josip; Pasarić, Zoran

2018-04-01

A common practice in meteorological drought monitoring is to transform the observed precipitation amounts to the standardised precipitation index (SPI). Though the gamma distribution is usually employed for this purpose, some other distribution may be used, particularly in regions where zero precipitation amounts are recorded frequently. In this study, two distributions are considered alongside with the gamma distribution: the compound Poisson exponential distribution (CPE) and the square root normal distribution (SRN). They are fitted to monthly precipitation amounts measured at 24 stations in Croatia in the 55-year-long period (1961-2015). At five stations, long-term series (1901-2015) are available and they have been used for a more detailed investigation. The accommodation of the theoretical distributions to empirical ones is tested by comparison of the corresponding empirical and theoretical ratios of the skewness and the coefficient of variation. Furthermore, following the common approach to precipitation monitoring (CLIMAT reports), the comparison of the empirical and theoretical quintiles in the two periods (1961-1990 and 1991-2015) is examined. The results from the present study reveal that it would be more appropriate to implement theoretical distributions in such climate reports, since they provide better evaluation for monitoring purposes than the current empirical distribution. Nevertheless, deciding on an optimal theoretical distribution for different climate regimes and for different time periods is not easy to accomplish. With regard to Croatian stations (covering different climate regimes), the CPE or SRN distribution could also be the right choice in the climatological practice, in addition to the gamma distribution.

Mechanical properties of jennite: A theoretical and experimental study

Energy Technology Data Exchange (ETDEWEB)

Moon, Juhyuk, E-mail: juhyuk.moon@stonybrook.edu [Civil Engineering Program, Department of Mechanical Engineering, Stony Brook University, NY 11794 (United States); Yoon, Seyoon [School of Engineering, Kings College, University of Aberdeen, Aberdeen AB24 3UE (United Kingdom); Monteiro, Paulo J.M. [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)

2015-05-15

The objective of this study is to determine the mechanical properties of jennite. To date, several hypotheses have been proposed to predict the structural properties of jennite. For the first time as reported herein, the isothermal bulk modulus of jennite was measured experimentally. Synchrotron-based high-pressure x-ray diffraction experiments were performed to observe the variation of lattice parameters under pressure. First-principles calculations were applied to compare with the experimental results and predict additional structural properties. Accurately measured isothermal bulk modulus herein (K{sub 0} = 64(2) GPa) and the statistical assessment on experimental and theoretical results suggest reliable mechanical properties of shear and Young's modulus, Poisson's ratio, and elastic tensor coefficients. Determination of these fundamental structural properties is the first step toward greater understanding of calcium–silicate–hydrate, as well as provides a sound foundation for forthcoming atomic level simulations.

Corporate social responsibility audit: Theoretical aspects

OpenAIRE

Artem Koldovskyi

2015-01-01

This paper puts a conceptual framework to outline research for corporate social responsibility (CSR) audit based on the analysis of current CRS literature and audit models as implementation of CSR. It is intended to make clear the phenomena about the relationship between audit, implementation of business ethics principles and corporate governance. However, most studies do not take into account modify CSR audit. This paper reports part of a research we carried out on the theoretical interpreta...

State of the Art Review on Theoretical Tribology of Fluid Power Displacement Machines

DEFF Research Database (Denmark)

Cerimagic, Remzija; Johansen, Per; Andersen, Torben O.

2016-01-01

machines, and also the work done to validate the theoretical models. This review is not a complete historical account, but aim to describe current trends in fluid power displacement machine tribology. The review considers the rheological models used in the theoretical approaches, the modeling...... and wear mechanisms in the lubricating gaps in fluid power machines is confined to simulation models, as experimental treatments of these mechanisms are very difficult. The aim of this paper is a state of the art review on the theoretical work for the design and optimization of fluid power displacement...... of elastohydrodynamic effects, the modeling of thermal effects, and finally the experimental validation of the theoretical models....

Traditional fire-use, landscape transition, and the legacies of social theory past.

Science.gov (United States)

Coughlan, Michael R

2015-12-01

Fire-use and the scale and character of its effects on landscapes remain hotly debated in the paleo- and historical-fire literature. Since the second half of the nineteenth century, anthropology and geography have played important roles in providing theoretical propositions and testable hypotheses for advancing understandings of the ecological role of human-fire-use in landscape histories. This article reviews some of the most salient and persistent theoretical propositions and hypotheses concerning the role of humans in historical fire ecology. The review discusses this history in light of current research agendas, such as those offered by pyrogeography. The review suggests that a more theoretically cognizant historical fire ecology should strive to operationalize transdisciplinary theory capable of addressing the role of human variability in the evolutionary history of landscapes. To facilitate this process, researchers should focus attention on integrating more current human ecology theory into transdisciplinary research agendas.

Validity of the Environmental Kuznets Curve Hypotheses in Water Pollution A Case Study

Directory of Open Access Journals (Sweden)

Hediyeh Alishiri

2017-03-01

Full Text Available Among the different environmental pollutions, water pollution is of especial importance due to the rather unchanging supply of this vital resource on a global scale and because of the dire consequences of its pollution for human health. The relationship between water production and its pollution can thus established and used as a measure of environmental degradation. This relationship can then be captured and analyzed in terms of environmental Kuznets hypotheses. It may be claimed that the early stages of economic growth is associated with lower per capita income and water pollution but the trend is reversed with increasing per capita income and improved economic growth. The present study was conducted using the panel data technique and the Kuznets environmental hypotheses were examined for the two groups of developed and developing countries under the two scenarios of using either per capita GDP or the share of industry to the added value in GDP as an indicator of economic growth. Results indicate that under both scenarios, Kuznets hypotheses are confirmed when studying the situation in developing countries but refuted in the case of developed countries.

Theoretical foundations of intercultural business communication and their practical consequences

Directory of Open Access Journals (Sweden)

Pikhart Marcel

2016-01-01

Full Text Available Intercultural business communication is well researched regarding theoretical foundations; however, we still lack practical consequences of this theoretical enquiry. The aim of the paper is to bring crucial practical implications which could be efficiently used in everyday business activity (such as negotiations, advertising and meetings in the current global business environment. The current reality of business communication is based purely on interaction with people from other cultures, backgrounds, nations and continents. To communicate successfully we make surface adaptation so that we are able to cross cultural boundaries and transcendent culture, and not only survive in today multicultural society but we manage to prosper, and even economically. When being aware of the differences in rhetoric style and conversational style in various cultures, we can become better communicators and negotiators and therefore be more successful in the global market.

Hypotheses on citation practices as revealed in the literature of the ...

African Journals Online (AJOL)

Citations found in two historical articles, which appeared in Cancer Research, a top American Journal, were used to show both positive and negative attitudes towards my 22 historical publications on cancer carriage in the body. Therefore, scientific information concepts are cited critically and two hypotheses are advanced ...

Examining Preservice Science Teachers' Skills of Formulating Hypotheses and Identifying Variables

Science.gov (United States)

Aydogdu, Bülent

2015-01-01

The aim of this study is to examine preservice science teachers' skills of formulating hypotheses and identifying variables. The research has a phenomenological research design. The data was gathered qualitatively. In this study, preservice science teachers were first given two scenarios (Scenario-1 & Scenario-2) containing two different…

Experimental study of neoclassical currents

International Nuclear Information System (INIS)

Zarnstorff, M.C.; Prager, S.C.

1985-05-01

A detailed experimental study is presented of the bootstrap and Pfirsch-Schlueter currents that are predicted by neoclassical transport theory. In a toroidal octupole, on magnetic surfaces within the separatrix, the observed parallel plasma currents are in excellent quantitative agreement with neoclassical theory with regard to the spatial structure (along a magnetic surface), collisionality dependence and toroidal magnetic field dependence. On magnetic surfaces outside the separatrix, the ion portion of the parallel current is in agreement with neoclassical theory but the electron parallel current is observed to obtain a unidirectional component which deviates from and exceeds the theoretical prediction

CMOS Current-mode Operational Amplifier

DEFF Research Database (Denmark)

Kaulberg, Thomas

1992-01-01

current-mode feedback amplifier or a constant bandwidth in a transimpedance feedback amplifier. The amplifier is found to have a gain bandwidth product of 8 MHz, an offset current of 0.8 ¿A (signal-range ±700¿A) and a (theoretically) unlimited slew-rate. The amplifier is realized in a standard CMOS 2......A fully differential-input differential-output current-mode operational amplifier (COA) is described. The amplifier utilizes three second generation current-conveyors (CCII) as the basic building blocks. It can be configured to provide either a constant gain-bandwidth product in a fully balanced...

Thermal domains in inhomogeneous current-carrying superconductors. Current-voltage characteriscs and dynamics of domain formation after current jumps

International Nuclear Information System (INIS)

Bezuglyj, A.I.; Shklovskij, V.A.

1984-01-01

The static and dynamic behavior of thermal domains in inhomogeneous superconducting films, where the inhomogeneity behaves like a portion of the film with a reduced critical current, have been studied theoretically within the framework of the phenomenological approach, using the heat balance equation and the dependence of the superconductor critical current on temperature. Depending on the size of the inhomogeneity (local or extended) and on the relative values of parameters of the homogeneous and inhomogeneous regions, different types of current-voltage characteristics are obtained. The nonstationary problem of thermal domain formation near the inhomogeneity after a current jump has been solved, and the domain boundary (kink) dynamics at a distance from the inhomogeneity has been analyzed. A combination of the results allows one to describe the whole process of normal phase formation and its spread throughout the superconducting film

Operating tokamaks with steady-state toroidal current

International Nuclear Information System (INIS)

Fisch, N.J.

1981-04-01

Continuous operation of a tokamak requires, among other things, a means of continuously providing the toroidal current. Various methods have been proposed to provide this current including methods which utilize radio-frequency waves in any of several frequency regimes. Here we elaborate on the prospects of incorporating these current-drive techniques in tokamak reactors, concentrating on the theoretical minimization of the power requirements

Non-inductively driven currents in JET

International Nuclear Information System (INIS)

Challis, C.D.; Cordey, J.G.; Hamnen, H.; Stubberfield, P.M.; Christiansen, J.P.; Lazzaro, E.; Muir, D.G.; Stork, D.; Thompson, E.

1989-01-01

Neutral beam heating data from JET have been analysed in detail to determine what proportion of the current is driven non-inductively. It is found that in low density limiter discharges, currents of the order of 0.5 MA are driven, while in H-mode plasmas currents of the order of 0.7 MA are measured. These measured currents are found to be in reasonable agreement with theoretical predictions based on neoclassical models. In low density plasmas the beam driven current is large while the neoclassical bootstrap current dominates H-mode plasmas. (author). 19 refs, 11 figs

Collaborative Learning: Theoretical Foundations and Applicable Strategies to University

Science.gov (United States)

Roselli, Nestor D.

2016-01-01

Collaborative learning is a construct that identifies a current strong field, both in face-to-face and virtual education. Firstly, three converging theoretical sources are analyzed: socio-cognitive conflict theory, intersubjectivity theory and distributed cognition theory. Secondly, a model of strategies that can be implemented by teachers to…

Current status of baryon spectroscopy

International Nuclear Information System (INIS)

Wali, K.C.

1975-01-01

The basic ideas of some of the current models and the experimental numerical comparisons are discussed briefly. Included are realistic or constituent quark models, experimental comparison, the experimental and theoretical basis for the assignments, algebraic quark models, and confinement schemes

Rewards and Creative Performance: A Meta-Analytic Test of Theoretically Derived Hypotheses

Science.gov (United States)

Byron, Kris; Khazanchi, Shalini

2012-01-01

Although many scholars and practitioners are interested in understanding how to motivate individuals to be more creative, whether and how rewards affect creativity remain unclear. We argue that the conflicting evidence may be due to differences between studies in terms of reward conditions and the context in which rewards are offered.…

The three stages of building and testing mid-level theories in a realist RCT: a theoretical and methodological case-example.

Science.gov (United States)

Jamal, Farah; Fletcher, Adam; Shackleton, Nichola; Elbourne, Diana; Viner, Russell; Bonell, Chris

2015-10-15

Randomised controlled trials (RCTs) of social interventions are often criticised as failing to open the 'black box' whereby they only address questions about 'what works' without explaining the underlying processes of implementation and mechanisms of action, and how these vary by contextual characteristics of person and place. Realist RCTs are proposed as an approach to evaluation science that addresses these gaps while preserving the strengths of RCTs in providing evidence with strong internal validity in estimating effects. In the context of growing interest in designing and conducting realist trials, there is an urgent need to offer a worked example to provide guidance on how such an approach might be practically taken forward. The aim of this paper is to outline a three-staged theoretical and methodological process of undertaking a realist RCT using the example of the evaluation of a whole-school restorative intervention aiming to reduce aggression and bullying in English secondary schools. First, informed by the findings of our initial pilot trial and sociological theory, we elaborate our theory of change and specific a priori hypotheses about how intervention mechanisms interact with context to produce outcomes. Second, we describe how we will use emerging findings from the integral process evaluation within the RCT to refine, and add to, these a priori hypotheses before the collection of quantitative, follow-up data. Third, we will test our hypotheses using a combination of process and outcome data via quantitative analyses of effect mediation (examining mechanisms) and moderation (examining contextual contingencies). The results are then used to refine and further develop the theory of change. The aim of the realist RCT approach is thus not merely to assess whether the intervention is effective or not, but to develop empirically informed mid-range theory through a three-stage process. There are important implications for those involved with reporting and

Hypothesized eye movements of neurolinguistic programming: a statistical artifact.

Science.gov (United States)

Farmer, A; Rooney, R; Cunningham, J R

1985-12-01

Neurolinguistic programming's hypothesized eye-movements were measured independently from videotapes of 30 subjects, aged 15 to 76 yr., who were asked to recall visual pictures, recorded audio sounds, and textural objects. chi 2 indicated that subjects' responses were significantly different from those predicted. When chi 2 comparisons were weighted by number of eye positions assigned to each modality (3 visual, 3 auditory, 1 kinesthetic), subjects' responses did not differ significantly from the expected pattern. These data indicate that the eye-movement hypothesis may represent randomly occurring rather than sensory-modality-related positions.

Electroweak Physics at the Tevatron and LHC: Theoretical Status and Perspectives

OpenAIRE

Baur, U.

2005-01-01

I review the status of theoretical calculations relevant for electroweak physics at the Tevatron and LHC and discuss future directions. I also give a brief overview of current electroweak data and discuss future expectations.

Validity of Memory Tasks across the WJ III COG, NEPSYII, and WRAML-2 in a Mixed Clinical Sample of Children: Applicability to Four Neurocognitive Theories

Science.gov (United States)

Psimas, J. Lynsey

2012-01-01

Current research regarding the neurocognitive construct of memory in children and adolescents within clinical populations is insufficient (Hughes & Graham, 2002). Controversial theories of memory have led to divergent hypotheses about the construct of memory. Based on current disparity regarding the theoretical paradigm of memory, it cannot be…

How the mainstream limits the spreading of alternative hypotheses

Science.gov (United States)

Kalenda, Pavel

2014-05-01

that prof. Djuric had tried for more than 10 years to publish this article in various peer-reviewed journals. So, prof. Djuric got into the official book (list) of "scientific dissidents" among hundreds of other professors and doctors of science (De Climont 2012). These "scientific dissidents" do not have access to established journals and may possibly publish privately or at best on the web in marginal journals whose list was published by De Climont (2012). Such a marginal journal in the field of geophysics and geology is New Concepts in Global Tectonics. This journal has been established because the current hypothesis about the movement of the continents due to convection currents in the mantle becomes under the weight of new observation quite untenable. 4) Scientific consensus History has known many hypotheses that were accepted as proven truth but later, in the light of new knowledge, they completely failed. - No one has the right to decide which scientific hypotheses will be accepted and which will not get into print. Perhaps the worst situation is in climatology (due to global effects and impacts), when the plenary session of IPCC consensually stated that the current global warming was mainly due to the human activity. References De Climont, J. (2012): The worldwide list of dissident scientists. http://astrojan.hostei.com/droa.htm. Djurič, J. (2006): Unification Of Gravitation And Electromagnetism. http://jovandjuric.tripod.com/ David H. Douglass, John R. Christy, Benjamin D. Pearson and S. Fred Singer (2007): A comparison of tropical temperature trends with model predictions. International Journal of Climatology, Volume 28, Issue 13, 15 November 2008, Pages: 1693-1701. http://onlinelibrary.wiley.com/doi/10.1002/joc.1651/pdf. Einstein, A. : List of scientific publications by Albert Einstein. /wiki/List_of_scientific_publications_by_Albert_Einstein. Kolínský, P., Valenta, J. and Gaždová, R. (2012): Seismicity, groundwater level variations and earth tides in

Theoretical inputs and errors in the new hadronic currents in TAUOLA

International Nuclear Information System (INIS)

Roig, P.; Nugent, I. M.; Przedzinski, T.; Shekhovtsova, O.; Was, Z.

2012-01-01

The new hadronic currents implemented in the TAUOLA library are obtained in the unified and consistent framework of Resonance Chiral Theory: a Lagrangian approach in which the resonances exchanged in the hadronic tau decays are active degrees of freedom included in a way that reproduces the low-energy results of Chiral Perturbation Theory. The short-distance QCD constraints on the imaginary part of the spin-one correlators yield relations among the couplings that render the theory predictive. In this communication, the obtaining of the two- and three-meson form factors is sketched. One of the criticisms to our framework is that the error may be as large as 1/3, since it is a realization of the large-N C limit of QCD in a meson theory. A number of arguments are given which disfavor that claim pointing to smaller errors, which would explain the phenomenological success of our description in these decays. Finally, other minor sources of error and current improvements of the code are discussed.

Theoretical inputs and errors in the new hadronic currents in TAUOLA

CERN Document Server

Roig, P; Przedzinski, T; Shekhovtsova, O; Was, Z

2012-01-01

The new hadronic currents implemented in the TAUOLA library are obtained in the unified and consistent framework of Resonance Chiral Theory: a Lagrangian approach in which the resonances exchanged in the hadronic tau decays are active degrees of freedom included in a way that reproduces the low-energy results of Chiral Perturbation Theory. The short-distance QCD constraints on the imaginary part of the spin-one correlators yield relations among the couplings that render the theory predictive. In this communication, the obtaining of the two- and three-meson form factors is sketched. One of the criticisms to our framework is that the error may be as large as 1/3, since it is a realization of the large-N_C limit of QCD in a meson theory. A number of arguments are given which disfavor that claim pointing to smaller errors, which would explain the phenomenological success of our description in these decays. Finally, other minor sources of error and current improvements of the code are discussed.

A new theoretical approach to analyze complex processes in cytoskeleton proteins.

Science.gov (United States)

Li, Xin; Kolomeisky, Anatoly B

2014-03-20

Cytoskeleton proteins are filament structures that support a large number of important biological processes. These dynamic biopolymers exist in nonequilibrium conditions stimulated by hydrolysis chemical reactions in their monomers. Current theoretical methods provide a comprehensive picture of biochemical and biophysical processes in cytoskeleton proteins. However, the description is only qualitative under biologically relevant conditions because utilized theoretical mean-field models neglect correlations. We develop a new theoretical method to describe dynamic processes in cytoskeleton proteins that takes into account spatial correlations in the chemical composition of these biopolymers. Our approach is based on analysis of probabilities of different clusters of subunits. It allows us to obtain exact analytical expressions for a variety of dynamic properties of cytoskeleton filaments. By comparing theoretical predictions with Monte Carlo computer simulations, it is shown that our method provides a fully quantitative description of complex dynamic phenomena in cytoskeleton proteins under all conditions.

Theoretical backgrounds of investigating of intellectual and human capital

Directory of Open Access Journals (Sweden)

Vladimir Nikiforovich Belkin

2011-03-01

Full Text Available This paper reviews the theoretical aspects of a company's intellectual capital. This capital consists of stock and movement of knowledge which is useful for organizing. There are three components of intellectual capital - human, social and organizational capital. The differences of intellectual and human capital are established. In particular, if human capital is characterized by mundane knowledge, the intellectual one - by the new, and if the products of human capital are the usual goods and services, the products of intellectual capital are the result of translating and implementing new knowledge. The coincidence of research subjects of the theory of intellectual capital and the theory of innovative enterprise development is shown. The concept of "intellectual potential of the enterprise" is introduced and the building structure is discussed. This potential consists of intellectual capital, patents and licenses unrealized by the enterprises, formalized ideas and hypotheses and undiscovered creative potential of the staff. Finally, a realization model of the intellectual potential of the company is proposed.

Characterization of Input Current Interharmonics in Adjustable Speed Drives

DEFF Research Database (Denmark)

Soltani, Hamid; Davari, Pooya; Zare, Firuz

2017-01-01

This paper investigates the interharmonic generation process in the input current of double-stage Adjustable Speed Drives (ASDs) based on voltage source inverters and front-end diode rectifiers. The effects of the inverter output-side low order harmonics, caused by implementing the double......-edge symmetrical regularly sampled Space Vector Modulation (SVM) technique, on the input current interharmonic components are presented and discussed. Particular attention is also given to the influence of the asymmetrical regularly sampled modulation technique on the drive input current interharmonics....... The developed theoretical analysis predicts the drive interharmonic frequency locations with respect to the selected sampling strategies. Simulation and experimental results on a 2.5 kW ASD system verify the effectiveness of the theoretical analysis....

Theoretical aspects of lepton-hadron scattering

International Nuclear Information System (INIS)

Drell, S.D.

1992-01-01

In this paper, I will emphasize two points on Theoretical Aspects of Lepton-Hadron Scattering: (1) The crucial importance of testing the ''exact'' sum rules as tests of the local current algebra. Discrepancies, if found, between experiment and theory cannot be ''interpreted away'' in terms of more complex parton wave functions for the hadronic ground state. The three sum rules of interest are those of Adler, Bjorken, and Gross and Llewellyn-Smith. (2) An understanding of the corrections to scaling in QCD and what they teach us

Modelling in Accounting. Theoretical and Practical Dimensions

OpenAIRE

Teresa Szot -Gabryś

2010-01-01

Accounting in the theoretical approach is a scientific discipline based on specific paradigms. In the practical aspect, accounting manifests itself through the introduction of a system for measurement of economic quantities which operates in a particular business entity. A characteristic of accounting is its flexibility and ability of adaptation to information needs of information recipients. One of the main currents in the development of accounting theory and practice is to cover by economic...

Chapter 2. Theoretical aspects of aluminium production

International Nuclear Information System (INIS)

Yanko, E.A.; Kabirov, Sh.O.; Safiev, Kh.; Azizov, B.S.; Mirpochaev, Kh.A.

2011-01-01

This article is devoted to theoretical aspects of aluminium production. Thus, the electrochemistry of electrolysis process, calculation of base industrial indicators of aluminium electrolytic cell, and processes occurring on anode and cathode were considered. Factors, which increase the current output and electrolytic cell productivity were studied. The side effects, including anode effect, sodium extraction on cathode, aluminium dissolution in the electrolyte, aluminium carbide formation, and influence of admixtures in the electrolyte were studied as well.

Characterising Information Systems in Australia: A Theoretical Framework

Directory of Open Access Journals (Sweden)

Gail Ridley

2006-11-01

Full Text Available The study reported in this volume aims to investigate the state of the Information Systems academic discipline in Australia from a historical and current perspective, collecting evidence across a range of dimensions. To maximise the strategic potential of the study, the results need to be capable of integration, so that the relationships within and across the dimensions and geographical units are understood. A meaningful theoretical framework will help relate the results of the different dimensions of the study to characterise the discipline in the region, and assist in empowering the Australian IS research community. This paper reviewed literature on the development of disciplines, before deriving a theoretical framework for the broader study reported in this volume. The framework considered the current and past state of IS in Australian universities from the perspective of the development of a discipline. The components of the framework were derived and validated through a thematic analysis of both the IS and non-IS literature. This paper also presents brief vignettes of the development of two other related disciplines. The framework developed in this paper, which has been partly guided by Whitley’s Theory of Scientific Change, has been used to analyse data collated from the Australian states and the Australian Capital Territory. The degree of variation in Australian IS as an indication of its “professionalisation”, the nature of its body of knowledge and its mechanisms of control, will be used to frame the analysis. Research reported in several of the papers that follow in this volume has drawn upon the theoretical framework presented below.

[Masculinity and femininity scales: current state of the art].

Science.gov (United States)

Fernández, Juan; Quiroga, María A; Del Olmo, Isabel; Rodríguez, Antonio

2007-08-01

A theoretical and empirical review of masculinity and femininity scales was carried out after 30 years of their existence. Hypotheses to be tested were: (a) muldimensionality versus bidimensionality; (b) inadequate percentage of variance accounted for (less than 50%); (c) inconsistency between factor structure and the dualistic model. 618, 200 and 287 students took part in each of the three studies that were carried out. Factorial analyses (PAF) were performed. Results support multidimensionality, unsatisfactory percentage of variance accounted for, and lack of congruence between obtained factors and the dualistic model. All these data were analysed within the context of the twofold sex and gender reality model.

Theoretical vs. actual energy consumption of labelled dwellings in the Netherlands: Discrepancies and policy implications

International Nuclear Information System (INIS)

Majcen, D.; Itard, L.C.M.; Visscher, H.

2013-01-01

In Europe, the Energy Performance of Buildings Directive (EPBD) provides for compulsory energy performance certification (labelling) for all existing dwellings. In the Netherlands, a labelling scheme was introduced in 2008. Certificates contain the energy label of the dwelling and corresponding theoretical gas and electricity consumption, calculated based on the dwellings physical characteristics, its heating, ventilation and cooling systems and standard use characteristics. This paper reports on a large-scale study of around 200,000 dwellings comparing labels and theoretical energy use with data on actual energy use. The study shows that dwellings with a low energy label actually consume much less energy than predicted by the label, but on the other hand, energy-efficient dwellings consume more than predicted. In practice, policy targets are set according to the theoretical rather than the actual consumptions of the building stock. In line with identified discrepancies, the study shows that whereas most energy reduction targets can be met according to the theoretical energy consumption of the dwelling stock, the future actual energy reduction potential is much lower and fails to meet most of the current energy reduction targets. - Highlights: ► Actual gas consumption in Dutch dwellings is lower than the theoretical. ► In the dwellings with label A–B, theoretical gas consumption is lower than actual gas consumption. ► In less efficient dwellings, theoretical gas consumption is much higher than the actual. ► Most current energy reduction targets are unachievable if modelled with actual instead of theoretical energy consumption

NegaWatt 2011-2050 scenario - Hypotheses and method. Technical report, May 2014

International Nuclear Information System (INIS)

2014-05-01

This report proposes an analysis of the negaWatt 2011 scenario. It describes in detail the methodology adopted to elaborate this prospective scenario, and presents the major part of the hypotheses which structure this scenario. A first part presents the approach and methodology (constraints, scenario, model). The second part addresses the issue of energy saving and energy efficiency through a sector-based analysis (housing and office building, transports, industrial and agricultural production). The third part studies the substitution by renewable energies through a supply analysis: energy production based on biomass, renewable energies, and fissile and fossil energies. It outlines the major role of grids in the supply-demand balance. The results of the negaWatt 2011 scenario are presented in terms of final energy, primary energies, and impact on greenhouse gas emissions. Hypotheses and results related to the different sectors (building, transports, industry and agriculture, energy production) are given in appendix

Computer modelling of superconductive fault current limiters

Energy Technology Data Exchange (ETDEWEB)

Weller, R.A.; Campbell, A.M.; Coombs, T.A.; Cardwell, D.A.; Storey, R.J. [Cambridge Univ. (United Kingdom). Interdisciplinary Research Centre in Superconductivity (IRC); Hancox, J. [Rolls Royce, Applied Science Division, Derby (United Kingdom)

1998-05-01

Investigations are being carried out on the use of superconductors for fault current limiting applications. A number of computer programs are being developed to predict the behavior of different `resistive` fault current limiter designs under a variety of fault conditions. The programs achieve solution by iterative methods based around real measured data rather than theoretical models in order to achieve accuracy at high current densities. (orig.) 5 refs.

Cellular properties of slug flow in vertical co-current gas-liquid flow: slug-churn transition

International Nuclear Information System (INIS)

Lusseyran, Francois

1990-01-01

This research thesis reports the study and description of the structure of a slug flow regime in a co-current vertical cylindrical duct, and the characterization and prediction of its transition towards a slug-churn (de-structured) regime. Flow physical mechanisms highlighted by the measurement of two important dynamics variables (wall friction and thickness of liquid films) are related to hypotheses of cellular models. The author first proposes an overview of slug flow regimes: theoretical steady and one-dimensional analysis, mass assessment equations of cellular models, application to the assessment of the flow rate and of the thickness of the film surrounding the gas slug. In the second part, the author addresses the slug flow regime transition towards the slug-churn regime: assessment of the evolution of flow dynamic properties, use of average wall friction analysis to obtain a relevant transition criterion. The third part presents experimental conditions, and measurement methods: conductometry for thickness measurement, polarography for wall friction measurement, and gas phase detection by using an optic barrier or optic fibres [fr

Current algebra and πΔ photoproduction

International Nuclear Information System (INIS)

Chaichian, M.; Nelipa, N.F.

1980-01-01

By using the improved technique of current algebra, sum rules for the process γ+N→π+Δ(1236) are obtained. The estimated value for the coupling constant π + Δ + Δ ++ is g 2 /4π=105 in good agreement with old experimental determinations and as well with other theoretical predictions, but in discrepancy with a recent partial wave analysis of the latest bubble chamber data. This might put doubts on the recent data (analysis), since otherwise all the theoretical evaluations should suffer from a common shortcoming. (author)

Current algebra constraints on K13 form factors

International Nuclear Information System (INIS)

Simmons, L.D.

1975-01-01

New theoretical constraints on the divergence form factor in K 13 decays are derived. The assumptions underlying the derivation are presented. The constraints on the divergence form factor are derived and summarized in the form of a theorem. It is shown that the finiteness of the leakage charge is a natural consequence of the parallelΔI vectorparallel = 1 / 2 rule. The Lorentz invariance of current algebra sum rules is discussed. The theorem is rederived within the context of the conserved vector current hypothesis. Finally, the implications of the present work are noted with attention being paid to both the theoretical and experimental consequences

Theoretical model of the SOS effect

Energy Technology Data Exchange (ETDEWEB)

Darznek, S A; Mesyats, G A; Rukin, S N; Tsiranov, S N [Russian Academy of Sciences, Ural Division, Ekaterinburg (Russian Federation). Institute of Electrophysics

1997-12-31

Physical principles underlying the operation of semiconductor opening switches (SOS) are highlighted. The SOS effect occurs at a current density of up to 60 kA/cm{sup 2} in silicon p{sup +}-p-n-n{sup +} structures filled with residual electron-hole plasma. Using a theoretical model developed for plasma dynamic calculations, the mechanism by which current passes through the structure at the stage of high conduction and the processes that take place at the stage of current interruption were analyzed. The dynamics of the processes taking place in the structure was calculated with allowance for both diffusive and drift mechanisms of carrier transport. In addition, two recombination types, viz. recombination via impurities and impact Auger recombination, were included in the model. The effect of the structure on the pumping-circuit current and voltage was also taken into account. The real distribution of the doped impurity in the structure and the avalanche mechanism of carrier multiplication were considered. The results of calculations of a typical SOS are presented. The dynamics of the electron-hole plasma is analyzed. It is shown that the SOS effect represents a qualitatively new mechanism of current interruption in semiconductor structures. (author). 4 figs., 7 refs.

A Theoretical Framework towards Understanding of Emotional and Behavioural Difficulties

Science.gov (United States)

Poulou, Maria S.

2014-01-01

Children's emotional and behavioural difficulties are the result of multiple individual, social and contextual factors working in concert. The current paper proposes a theoretical framework to interpret students' emotional and behavioural difficulties in schools, by taking into consideration teacher-student relationships, students'…

An Attachment Theoretical Framework for Understanding Personality Disorders: Developmental, Neuroscience, and Psychotherapeutic Considerations

Directory of Open Access Journals (Sweden)

Kenneth N. Levy

2015-04-01

Full Text Available In this paper we propose that John Bowlby's attachment theory provides a theoretically coherent, empirically based, and clinically useful model for understanding personality pathology. This theoretical framework brings parsimony and breadth to the conceptualization of the etiology, maintenance, and treatment of personality disorders (PDs. Attachment theory can explain both the intrapersonal and interpersonal difficulties common in those with PDs and is consistent with findings from studies across multiple domains of knowledge, including evolutionary biology, ethology/comparative psychology, developmental psychology, experimental social-personality psychology, and neuroscience.PDs are characterized by significant interpersonal challenges. Recently, these challenges have been hypothesized to stem from underlying maladaptive attachment schemas. Our goal is to outline and elaborate on attachment theory as a foundation for the etiology and pathology of PDs and to highlight the implications of this theory for treatment. We begin with a brief review of attachment, describing its conceptualization and assessment in both children and adults in order to examine PD development. This theoretical foundation is supported by a body of empirical research, from which we present findings from neurobiological and developmental literatures linking attachment and PDs. We then examine the role of attachment in the psychotherapy process and in treatment outcome. Further, we outline research reporting changes in attachment patterns as a result of treatment. Finally, we summarize the implications of attachment theory for understanding PDs and present possible directions for future research.

Properties of hypothesis testing techniques and (Bayesian) model selection for exploration-based and theory-based (order-restricted) hypotheses.

Science.gov (United States)

Kuiper, Rebecca M; Nederhoff, Tim; Klugkist, Irene

2015-05-01

In this paper, the performance of six types of techniques for comparisons of means is examined. These six emerge from the distinction between the method employed (hypothesis testing, model selection using information criteria, or Bayesian model selection) and the set of hypotheses that is investigated (a classical, exploration-based set of hypotheses containing equality constraints on the means, or a theory-based limited set of hypotheses with equality and/or order restrictions). A simulation study is conducted to examine the performance of these techniques. We demonstrate that, if one has specific, a priori specified hypotheses, confirmation (i.e., investigating theory-based hypotheses) has advantages over exploration (i.e., examining all possible equality-constrained hypotheses). Furthermore, examining reasonable order-restricted hypotheses has more power to detect the true effect/non-null hypothesis than evaluating only equality restrictions. Additionally, when investigating more than one theory-based hypothesis, model selection is preferred over hypothesis testing. Because of the first two results, we further examine the techniques that are able to evaluate order restrictions in a confirmatory fashion by examining their performance when the homogeneity of variance assumption is violated. Results show that the techniques are robust to heterogeneity when the sample sizes are equal. When the sample sizes are unequal, the performance is affected by heterogeneity. The size and direction of the deviations from the baseline, where there is no heterogeneity, depend on the effect size (of the means) and on the trend in the group variances with respect to the ordering of the group sizes. Importantly, the deviations are less pronounced when the group variances and sizes exhibit the same trend (e.g., are both increasing with group number). © 2014 The British Psychological Society.

Theoretical modelling of semiconductor surfaces microscopic studies of electrons and photons

CERN Document Server

Srivastava, G P

1999-01-01

The state-of-the-art theoretical studies of ground state properties, electronic states and atomic vibrations for bulk semiconductors and their surfaces by the application of the pseudopotential method are discussed. Studies of bulk and surface phonon modes have been extended by the application of the phenomenological bond charge model. The coverage of the material, especially of the rapidly growing and technologically important topics of surface reconstruction and chemisorption, is up-to-date and beyond what is currently available in book form. Although theoretical in nature, the book provides

Modelling in Accounting. Theoretical and Practical Dimensions

Directory of Open Access Journals (Sweden)

Teresa Szot-Gabryś

2010-10-01

Full Text Available Accounting in the theoretical approach is a scientific discipline based on specific paradigms. In the practical aspect, accounting manifests itself through the introduction of a system for measurement of economic quantities which operates in a particular business entity. A characteristic of accounting is its flexibility and ability of adaptation to information needs of information recipients. One of the main currents in the development of accounting theory and practice is to cover by economic measurements areas which have not been hitherto covered by any accounting system (it applies, for example, to small businesses, agricultural farms, human capital, which requires the development of an appropriate theoretical and practical model. The article illustrates the issue of modelling in accounting based on the example of an accounting model developed for small businesses, i.e. economic entities which are not obliged by law to keep accounting records.

Spin currents in metallic nanostructures

Energy Technology Data Exchange (ETDEWEB)

Czeschka, Franz Dominik

2011-09-05

A pure spin current, i.e., a flow of angular momentum without accompanying net charge current, is a key ingredient in the field of spintronics. In this thesis, we experimentally investigated two different concepts for pure spin current sources suggested by theory. The first is based on a time-dependent magnetization precession which ''pumps'' a pure spin current into an adjacent non-magnetic conductor. Our experiments quantitatively corroborated important predictions expected theoretically for this approach, including the dependence of the spin current on the sample geometry and the microwave power. Even more important, we could show for the first time that the spin pumping concept is viable in a large variety of ferromagnetic materials and that it only depends on the magnetization damping. Therefore, our experiments established spin pumping as generic phenomenon and demonstrated that it is a powerful way to generate pure spin currents. The second theoretical concept is based on the conversion of charge currents into spin currents in non-magnetic nanostructures via the spin Hall effect. We experimentally investigated this approach in H-shaped, metallic nanodevices, and found that the predictions are linked to requirements not realizable with the present experimental techniques, neither in sample fabrication nor in measurement technique. Indeed, our experimental data could be consistently understood by a spin-independent transport model describing the transition from diffusive to ballistic transport. In addition, the implementation of advanced fabrication and measurement techniques allowed to discover a new non-local phenomenon, the non-local anisotropic magnetoresistance. Finally, we also studied spin-polarized supercurrents carried by spin-triplet Cooper pairs. We found that low resistance interfaces are a key requirement for further experiments in this direction. (orig.)

De bruikbaarheid van de ‘shaken baby syndroom’-hypothese in het strafproces

NARCIS (Netherlands)

Hoving, R.A.

In het Nederlandse strafproces wordt regelmatig gebruik gemaakt van deskundigenbewijs van deskundigen die uitgaan van de ‘shaken baby syndroom’-hypothese om aan te tonen dat een verdachte een baby heeft mishandeld of gedood. In onder meer de Verenigde Staten en Engeland woedt een felle discussie

The Ranschburg Effect: Tests of the Guessing-Bias and Proactive Interference Hypotheses

Science.gov (United States)

Walsh, Michael F.; Schwartz, Marian

1977-01-01

The guessing-bias and proactive interference hypotheses of the Ranschburg Effect were investigated by giving three groups different instructions as to guessing during recall. Results failed to support the prediction that the effect should be reduced or eliminated on shift trials. Neither hypothesis received significant support. (CHK)

Theoretical issues in PDF determination and associated uncertainties

CERN Document Server

Ball, Richard D.; Del Debbio, Luigi; Forte, Stefano; Guffanti, Alberto; Rojo, Juan; Ubiali, Maria

2013-01-01

We study several sources of theoretical uncertainty in the determination of parton distributions (PDFs) which may affect current PDF sets used for precision physics at the Large Hadron Collider, and explain discrepancies between them. We consider in particular the use of fixed-flavor versus variable-flavor number renormalization schemes, higher twist corrections, and nuclear corrections. We perform our study in the framework of the NNPDF2.3 global PDF determination, by quantifying in each case the impact of different theoretical assumptions on the output PDFs. We also study in each case the implications for benchmark cross sections at the LHC. We find that the impact in a global fit of a fixed-flavor number scheme is substantial, the impact of higher twists is negligible, and the impact of nuclear corrections is moderate and circumscribed.

Procoagulant State in Current and Former Anabolic Androgenic Steroid Abusers

DEFF Research Database (Denmark)

Chang, Simon; Rasmussen, Jon J; Frandsen, Mikkel N

2018-01-01

BACKGROUND:  Anabolic androgenic steroid (AAS) abusers are considered at increased risk of cardiovascular morbidity and mortality. We hypothesized that current and former AAS abuse would induce a procoagulant shift in the haemostatic balance. METHODS:  Men 18 to 50 years of age were included...

Urinary plasmin activates collecting duct ENaC current in preeclampsia

DEFF Research Database (Denmark)

Buhl, KB; Friis, Ulla Glenert; Svenningsen, Per

2012-01-01

In nephrotic syndrome, plasminogen is aberrantly filtered from plasma to the urinary space and activated along the tubular system. In vitro, plasmin increases ENaC current by proteolytic cleavage of the γ-subunit. It was hypothesized that preeclampsia is associated with plasmin-dependent ability...

Computational Identification of Novel Genes: Current and Future Perspectives.

Science.gov (United States)

Klasberg, Steffen; Bitard-Feildel, Tristan; Mallet, Ludovic

2016-01-01

While it has long been thought that all genomic novelties are derived from the existing material, many genes lacking homology to known genes were found in recent genome projects. Some of these novel genes were proposed to have evolved de novo, ie, out of noncoding sequences, whereas some have been shown to follow a duplication and divergence process. Their discovery called for an extension of the historical hypotheses about gene origination. Besides the theoretical breakthrough, increasing evidence accumulated that novel genes play important roles in evolutionary processes, including adaptation and speciation events. Different techniques are available to identify genes and classify them as novel. Their classification as novel is usually based on their similarity to known genes, or lack thereof, detected by comparative genomics or against databases. Computational approaches are further prime methods that can be based on existing models or leveraging biological evidences from experiments. Identification of novel genes remains however a challenging task. With the constant software and technologies updates, no gold standard, and no available benchmark, evaluation and characterization of genomic novelty is a vibrant field. In this review, the classical and state-of-the-art tools for gene prediction are introduced. The current methods for novel gene detection are presented; the methodological strategies and their limits are discussed along with perspective approaches for further studies.

A CMOS current-mode operational amplifier

DEFF Research Database (Denmark)

Kaulberg, Thomas

1993-01-01

current-mode feedback amplifier or a constant bandwidth in a transimpedance feedback amplifier. The amplifier is found to have a gain-bandwidth product of 3 MHz, an offset current of 0.8 μA (signal range ±700 μA), and a (theoretically) unlimited slew rate. The amplifier is realized in a standard CMOS 2......A fully differential-input, differential-output, current-mode operational amplifier (COA) is described. The amplifier utilizes three second-generation current conveyors (CCIIs) as the basic building blocks. It can be configured to provide either a constant gain-bandwidth product in a fully balanced...

Brains on Wheels: Theoretical and Ethical Issues in Bio-Robotics

DEFF Research Database (Denmark)

Bentzen, Martin Mose

2014-01-01

A number of theoretical problems and a couple of ethical issues in bio-robotics are investigated. It is found that claims made by researchers to have constructed robots controlled by rat brains are not fully justified by the results of current research. Further, the ethical implications of the re...

Current status of baryon spectroscopy

International Nuclear Information System (INIS)

Wali, K.C.

1975-08-01

In this review of baryon spectroscopy, the basic ideas of some of the current models and the experimental data for their claims to success are discussed including realistic or constituent quark models, experimental comparison, the experimental and theoretical basis for the assignments, algebraic quark models, and confinement schemes

The RNA-world and co-evolution hypotheses and the origin of life: Implications, research strategies and perspectives

Science.gov (United States)

Lahav, Noam

1993-12-01

The applicability of the RNA-world and co-evolution hypotheses to the study of the very first stages of the origin of life is discussed. The discussion focuses on the basic differences between the two hypotheses and their implications, with regard to the reconstruction methodology, ribosome emergence, balance between ribozymes and protein enzymes, and their major difficulties. Additional complexities of the two hypotheses, such as membranes and the energy source of the first reactions, are not treated in the present work. A central element in the proposed experimental strategies is the study of the catalytic activities of very small peptides and RNA-like oligomers, according to existing, as well as to yet-to-be-invented scenarios of the two hypotheses under consideration. It is suggested that the noveldirected molecular evolution technology, andmolecular computational modeling, can be applied to this research. This strategy is assumed to be essential for the suggested goal of future studies of the origin of life, namely, the establishment of a ‘Primordial Darwinian entity’.

Testing evolutionary hypotheses for phenotypic divergence using landscape genetics.

Science.gov (United States)

Funk, W Chris; Murphy, Melanie A

2010-02-01

Understanding the evolutionary causes of phenotypic variation among populations has long been a central theme in evolutionary biology. Several factors can influence phenotypic divergence, including geographic isolation, genetic drift, divergent natural or sexual selection, and phenotypic plasticity. But the relative importance of these factors in generating phenotypic divergence in nature is still a tantalizing and unresolved problem in evolutionary biology. The origin and maintenance of phenotypic divergence is also at the root of many ongoing debates in evolutionary biology, such as the extent to which gene flow constrains adaptive divergence (Garant et al. 2007) and the relative importance of genetic drift, natural selection, and sexual selection in initiating reproductive isolation and speciation (Coyne & Orr 2004). In this issue, Wang & Summers (2010) test the causes of one of the most fantastic examples of phenotypic divergence in nature: colour pattern divergence among populations of the strawberry poison frog (Dendrobates pumilio) in Panama and Costa Rica (Fig. 1). This study provides a beautiful example of the use of the emerging field of landscape genetics to differentiate among hypotheses for phenotypic divergence. Using landscape genetic analyses, Wang & Summers were able to reject the hypotheses that colour pattern divergence is due to isolation-by-distance (IBD) or landscape resistance. Instead, the hypothesis left standing is that colour divergence is due to divergent selection, in turn driving reproductive isolation among populations with different colour morphs. More generally, this study provides a wonderful example of how the emerging field of landscape genetics, which has primarily been applied to questions in conservation and ecology, now plays an essential role in evolutionary research.

A Decentralized Approach to the Formulation of Hypotheses: A Hierarchical Structural Model for a Prion Self-Assembled System

Science.gov (United States)

Wang, Mingyang; Zhang, Feifei; Song, Chao; Shi, Pengfei; Zhu, Jin

2016-07-01

Innovation in hypotheses is a key transformative driver for scientific development. The conventional centralized hypothesis formulation approach, where a dominant hypothesis is typically derived from a primary phenomenon, can, inevitably, impose restriction on the range of conceivable experiments and legitimate hypotheses, and ultimately impede understanding of the system of interest. We report herein the proposal of a decentralized approach for the formulation of hypotheses, through initial preconception-free phenomenon accumulation and subsequent reticular logical reasoning processes. The two-step approach can provide an unbiased, panoramic view of the system and as such should enable the generation of a set of more coherent and therefore plausible hypotheses. As a proof-of-concept demonstration of the utility of this open-ended approach, a hierarchical model has been developed for a prion self-assembled system, allowing insight into hitherto elusive static and dynamic features associated with this intriguing structure.

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.

Bullying Victimization and Adolescent Self-Harm: Testing Hypotheses from General Strain Theory

Science.gov (United States)

Hay, Carter; Meldrum, Ryan

2010-01-01

Self-harm is widely recognized as a significant adolescent social problem, and recent research has begun to explore its etiology. Drawing from Agnew's (1992) social psychological strain theory of deviance, this study considers this issue by testing three hypotheses about the effects of traditional and cyber bullying victimization on deliberate…

Streaming current and wall dissolution over 48h in silica nanochannels

DEFF Research Database (Denmark)

Andersen, Mathias Bækbo; Bruus, Henrik; Bardhan, Jaydeep P.

2011-01-01

We present theoretical and experimental studies of the streaming current induced by a pressure-driven flow in long, straight, electrolyte-filled nanochannels. The theoretical work builds on our recent one-dimensional model of electro-osmotic and capillary flow, which self-consistently treats both...

Measuring health lifestyles in a comparative analysis: theoretical issues and empirical findings.

Science.gov (United States)

Abel, T

1991-01-01

The concept of lifestyle bears great potential for research in medical sociology. Yet, weaknesses in current methods have restrained lifestyle research from realizing its full potentials. The present focus is on the links between theoretical conceptions and their empirical application. The paper divides into two parts. The first part provides a discussion of basic theoretical and methodological issues. In particular selected lines of thought from Max Weber are presented and their usefulness in providing a theoretical frame of reference for health lifestyle research is outlined. Next, a theory guided definition of the subject matter is introduced and basic problems in empirical applications of theoretical lifestyle concepts are discussed. In its second part the paper presents findings from comparative lifestyle analyses. Data from the U.S. and West Germany are utilized to explore issues of measurement equivalence and theoretical validity. Factor analyses indicate high conceptual equivalence for new measures of health lifestyle dimensions in both the U.S. and West Germany. Divisive cluster analyses detect three distinct lifestyle groups in both nations. Implications for future lifestyle research are discussed.

Oxidation of organics in water in microfluidic electrochemical reactors: Theoretical model and experiments

International Nuclear Information System (INIS)

Scialdone, Onofrio; Guarisco, Chiara; Galia, Alessandro

2011-01-01

The electrochemical oxidation of organics in water performed in micro reactors on boron doped diamond (BDD) anode was investigated both theoretically and experimentally in order to find the influence of various operative parameters on the conversion and the current efficiency CE of the process. The electrochemical oxidation of formic acid (FA) was selected as a model case. High conversions for a single passage of the electrolytic solution inside the cell were obtained by operating with proper residence times and low distances between cathode and anode. The effect of initial concentration, flow rate and current density was investigated in detail. Theoretical predictions were in very good agreement with experimental results for both mass transfer control, oxidation reaction control and mixed kinetic regimes in spite of the fact that no adjustable parameters was used. Mass transfer process was successfully modelled by considering for simplicity a constant Sh number (e.g., a constant mass transfer coefficient k m ) for a process performed with no high values of the current intensity to minimize the effect of the gas bubbling on the flowdynamic pattern. For mixed kinetic regimes, two different modelling approaches were used. In the first one, the oxidation of organics at BDD was assumed to be mass transfer controlled and to occur with an intrinsic 100% CE when applied current density is higher than the limiting current density. In the second case, the CE of the process was modelled assuming that the competition between organic and water oxidation depends only on the electrodic material and on the nature and the concentration of the organic. In the latter case a better agreement between experimental data and theoretical predictions was observed.

Charging/discharging processes in nanocrystaline MOS structures - Theoretical study

International Nuclear Information System (INIS)

Tanous, D; Mazurak, A; Majkusiak, B

2016-01-01

We present the study of impact of some parameters of the metal-insulator-semiconductor structure with nanocrystals embedded in the insulator layer on the current-voltage and capacitance-voltage characteristics with the bias voltage ramp rate as a parameter. The developed model is used as a tool for theoretical understanding the physics behind charging and discharging processes in the considered structures. (paper)

Magnetoacoustic waves in current-carrying plasmas

International Nuclear Information System (INIS)

Brennan, M.H.

1980-04-01

The results of theoretical and experimental investigations of the characteristics of magnetoacoustic waves in non-uniform, current-carrying plasmas are reviewed. Dissipative MHD and collisionless theories are considered. Also discussed is the use of magnetoacoustic waves in plasma diagnostics and plasma heating

Educational Transitions in Israel: A Test of the Industrialization and Credentialism Hypotheses.

Science.gov (United States)

Shavit, Yossi; Kraus, Vered

1990-01-01

Explores the industrialization and credentialism hypotheses and predictions of educational attainment levels. Finds the effects of the father's education and occupation were stable for those attending school in the 1940s, 1950s, and 1960s. Notes that the effects of ethnicity declined in the transition from primary to secondary school. (NL)

Exercise and Early-Onset Alzheimer’s Disease: Theoretical Considerations

Directory of Open Access Journals (Sweden)

Astrid M. Hooghiemstra

2012-04-01

Full Text Available Background/Aims: Although studies show a negative relationship between physical activity and the risk for cognitive impairment and late-onset Alzheimer’s disease, studies concerning early-onset Alzheimer’s disease (EOAD are lacking. This review aims to justify the value of exercise interventions in EOAD by providing theoretical considerations that include neurobiological processes. Methods: A literature search on key words related to early-onset dementia, exercise, imaging, neurobiological mechanisms, and cognitive reserve was performed. Results/Conclusion: Brain regions and neurobiological processes contributing to the positive effects of exercise are affected in EOAD and, thus, provide theoretical support for exercise interventions in EOAD. Finally, we present the design of a randomized controlled trial currently being conducted in early-onset dementia patients.

Theoretical predictions for glass flow into an evacuated canister

International Nuclear Information System (INIS)

Routt, K.R.; Crow, K.R.

1983-01-01

Radioactive waste currently stored at the Savannah River Plant in liquid form is to be immobilized by incorporating it into a borosilicate glass. The glass melter for this process will consist of a refractory lined, steel vessel operated at a glass temperature of 1150 0 C. At the end of a two-year projected melter lifetime, the glass inside the melter is to be drained prior to disposition of the melter vessel. One proposed technique for accomplishing this drainage is by sucking the glass into an evacuated canister. The theoretical bases for design of an evacuated canister for draining a glass melter have been developed and tested. The theoretical equations governing transient and steady-state flow were substantiated with both a silicone glass simulant and molten glass

Kolmogorov similarity hypotheses for scalar fields: sampling intermittent turbulent mixing in the ocean and galaxy

International Nuclear Information System (INIS)

Gibson, C.H.

1991-01-01

Kolmogorov's three universal similarity hypotheses are extrapolated to describe scalar fields like temperature mixed by turbulence. The analogous first and second hypotheses for scalars include the effects of Prandtl number and rate-of-strain mixing. Application of velocity and scalar similarity hypotheses to the ocean must take into account the damping of active turbulence by density stratification and the Earth's rotation to form fossil turbulence. By the analogous Kolmogorov third hypothesis for scalars, temperature dissipation rates χ averaged over lengths r > L K should be lognormally distributed with intermittency factors σ 2 that increase with increasing turbulence energy length scales L O as σ ln r 2 approx = μ θ ln(L O /r). Tests of kolmogorovian velocity and scalar universal similarity hypotheses for very large ranges of turbulence length and timescales are provided by data from the ocean and the galactic interstellar medium. These ranges are from 1 to 9 decades in the ocean, and over 12 decades in the interstellar medium. The universal constant for turbulent mixing intermittency μ θ is estimated from oceanic data to be 0.44±0.01, which is remarkably close to estimates for Kolmorgorov's turbulence intermittency constant μ of 0.45±0.05 from galactic as well as atmospheric data. Extreme intermittency complicates the oceanic sampling problem, and may lead to quantitative and qualitative undersampling errors in estimates of mean oceanic dissipation rates and fluxes. Intermittency of turbulence and mixing in the interstellar medium may be a factor in the formation of stars. (author)

Theoretical Characterizaiton of Visual Signatures (Muzzle Flash)

Science.gov (United States)

Kashinski, D. O.; Scales, A. N.; Vanderley, D. L.; Chase, G. M.; di Nallo, O. E.; Byrd, E. F. C.

2014-05-01

We are investigating the accuracy of theoretical models used to predict the visible, ultraviolet and infrared spectra of product materials ejected from the muzzle of currently fielded systems. Recent advances in solid propellants has made the management of muzzle signature (flash) a principle issue in weapons development across the calibers. A priori prediction of the electromagnetic spectra of formulations will allow researchers to tailor blends that yield desired signatures and determine spectrographic detection ranges. We are currently employing quantum chemistry methods at various levels of sophistication to optimize molecular geometries, compute vibrational frequencies, and determine the optical spectra of specific gas-phase molecules and radicals of interest. Electronic excitations are being computed using Time Dependent Density Functional Theory (TD-DFT). A comparison of computational results to experimental values found in the literature is used to assess the affect of basis set and functional choice on calculation accuracy. The current status of this work will be presented at the conference. Work supported by the ARL, and USMA.

Theoretical Perspectives of Enterprise Architecture for Technological Transformation

DEFF Research Database (Denmark)

Tambo, Torben

2017-01-01

The purpose of this article is to investigate the completeness of the theoretical foundations of Enterprise Architecture (EA) by reviewing four selected disciplines from Management of Technology (MOT). Often theory on EA is based on prior EA contributions or more distant contributions such as ser......The purpose of this article is to investigate the completeness of the theoretical foundations of Enterprise Architecture (EA) by reviewing four selected disciplines from Management of Technology (MOT). Often theory on EA is based on prior EA contributions or more distant contributions...... such as service science, semiotics, psycho-social constructs, business process analytics, and systems science. It is here argued that other theories might be more supportive to EA. The current article is based on a review of the MOT literature and a subsequent literature review within each of the four specialized...

Mapping For Literature Conceptual And Theoretical Framework And Methodology Case Of Hot Deep Mining Ventilation Engineering Evaluation And Design

Directory of Open Access Journals (Sweden)

Peter M. Lukonde

2017-09-01

Full Text Available The paper reports the layout of a mapping process for literature theoretical and conceptual framework and methodology for mining ventilation engineering evaluation design and methodology for a hot deep mine. The purpose of mine ventilation is to provide suitable environmental conditions in working places that promote comfort and efficiency as well as the safety and health of underground personnel. The objectives addressed in this paper include a evaluation of a current mine ventilation system for a hot deep-level mine taking into account the existing ventilation system infrastructure for building of a mine ventilation baseline parametric database for subsequent end of life mine ventilation design and b design of the extension end of mine life ventilation system taking into account increased production high geothermic gradient and subsequent increase in depth of mining. The methodology used in evaluating an existing underground mine ventilation system and designing the extension end of mine life ventilation system employed three stages i Literature mapping to identify authors titles and technical papers at global regional and nationaldistrict scales relevant to the research ii Conceptual and theoretical framework mapping to extract a kernel or core of concepts hypotheses and theories from the literature map to drive the formation of methods of implementation and iii Methodology and implementation mapping to direct and control the processes of data collection analysis and interpretation. A sample case study of a deep-level underground mine has been used in this paper to provide examples of data collection data analysis and interpretation key findings and results discussion and what is new conclusions and recommendations when the proposed mapping process is employed.

Theoretical nuclear physics

CERN Document Server

Blatt, John M

1979-01-01

A classic work by two leading physicists and scientific educators endures as an uncommonly clear and cogent investigation and correlation of key aspects of theoretical nuclear physics. It is probably the most widely adopted book on the subject. The authors approach the subject as ""the theoretical concepts, methods, and considerations which have been devised in order to interpret the experimental material and to advance our ability to predict and control nuclear phenomena.""The present volume does not pretend to cover all aspects of theoretical nuclear physics. Its coverage is restricted to

About hypotheses and paradigms: exploring the Discreetness-Chance Paradigm.

Science.gov (United States)

Kaellis, Eugene

2006-01-01

Hypotheses generally conform to paradigms which, over time, change, usually tardily, after they have become increasingly difficult to sustain under the impact of non-conforming evidence and alternative hypotheses, but more important, when they no longer are comfortably ensconced in the surrounding social-economic-political-cultural milieu. It is asserted that this milieu is the most important factor in shaping scientific theorizing. Some examples are cited: the rejection of the evidence that the world orbits around the sun (suspected by Pythagoras) in favor of centuries-long firm adherence to the Ptolemaic geocentric system; the early acceptance of Natural Selection in spite of its tautological essence and only conjectural supporting evidence, because it justified contemporaneous social-political ideologies as typified by, e.g., Spencer and Malthus. Economic, social, and cultural factors are cited as providing the ground, i.e., ideational substrate, for what is cited as the Discreetness-Chance Paradigm (DCP), that has increasingly dominated physics, biology, and medicine for over a century and which invokes small, discrete packets of energy/matter (quanta, genes, microorganisms, aberrant cells) functioning within an environment of statistical, not determined, causality. There is speculation on a possible paradigmatic shift from the DCP, which has fostered the proliferation, parallel with ("splitting") taxonomy, of alleged individual disease entities, their diagnoses, and, when available, their specific remedies, something particularly prominent in, e.g., psychiatry's Diagnostic and Statistical Manual, a codified compendium of alleged mental and behavioral disorders, but evident in any textbook of diagnosis and treatment of physical ailments. This presumed paradigm shift may be reflected in Western medicine, presently increasingly empirical and atomized, towards a growing acceptance of a more generalized, subject-oriented, approach to health and disease, a non

Limits on hypothesizing new quantum numbers

International Nuclear Information System (INIS)

Goldstein, G.R.; Moravcsik, M.J.

1986-01-01

According to a recent theorem, for a general quantum-mechanical system undergoing a process, one can tell from measurements on this system whether or not it is characterized by a quantum number, the existence of which is unknown to the observer, even though the detecting equipment used by the observer is unable to distinguish among the various possible values of the ''secret'' quantum number and hence always averages over them. The present paper deals with situations in which this averaging is avoided and hence the ''secret'' quantum number remains ''secret.'' This occurs when a new quantum number is hypothesized in such a way that all the past measurements pertain to the system with one and the same value of the ''secret'' quantum number, or when the new quantum number is related to the old ones by a specific dynamical model providing a one-to-one correspondence. In the first of these cases, however, the one and the same state of the ''secret'' quantum number needs to be a nondegenerate one. If it is degenerate, the theorem can again be applied. This last feature provides a tool for experimentally testing symmetry breaking and the reestablishment of symmetries in asymptotic regions. The situation is illustrated on historical examples like isospin and strangeness, as well as on some contemporary schemes involving spaces of higher dimensionality

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.

Theoretical chemistry in Belgium a topical collection from theoretical chemistry accounts

CERN Document Server

Champagne, Benoît; De Proft, Frank; Leyssens, Tom

2014-01-01

Readers of this volume can take a tour around the research locations in Belgium which are active in theoretical and computational chemistry. Selected researchers from Belgium present research highlights of their work. Originally published in the journal Theoretical Chemistry Accounts, these outstanding contributions are now available in a hardcover print format. This volume will be of benefit in particular to those research groups and libraries that have chosen to have only electronic access to the journal. It also provides valuable content for all researchers in theoretical chemistry.

Smart Companies, Inspiring the Future: A Theoretical Review

OpenAIRE

Echazarreta Soler, Carmen; Costa Marcé, Albert

2017-01-01

The economic and financial global crises have accelerated the search for alternative business models. The aim of this article is to describe the main characteristics of smart companies capable of overcoming the shortcomings of the current economic system. After conducting a theoretical review of the main studies related to this area, we conclude that there is a need for smart companies championed by leaders who promote the use of information technologies and communication as means...

Distinguishing 'Higgs' spin hypotheses using γγ and WW* decays

International Nuclear Information System (INIS)

Ellis, John; Fok, Ricky; Hwang, Dae Sung; Sanz, Veronica; You, Tevong

2013-01-01

The new particle X recently discovered by the ATLAS and CMS Collaborations in searches for the Higgs boson has been observed to decay into γγ, ZZ * and WW * , but its spin and parity, J P , remain a mystery, with J P = 0 + and 2 + being open possibilities. We use PYTHIA and Delphes to simulate an analysis of the angular distribution of gg → X → γγ decays in a full 2012 data set, including realistic background levels. We show that this angular distribution should provide strong discrimination between the possibilities of spin zero and spin two with graviton-like couplings: ∝3 σ if a conservative symmetric interpretation of the log-likelihood ratio (LLR) test statistic is used, and ∝6 σ if a less conservative asymmetric interpretation is used. The WW and ZZ couplings of the Standard Model Higgs boson and of a 2 + particle with graviton-like couplings are both expected to exhibit custodial symmetry. We simulate the present ATLAS and CMS search strategies for X → WW * using PYTHIA and Delphes, and show that their efficiencies in the case of a spin-2 particle with graviton-like couplings are a factor ≅ 1.9 smaller than in the spin-0 case. On the other hand, the ratio of X 2 + → WW * and ZZ * branching ratios is larger than that in the 0 + case by a factor ≅ 1.3. We find that the current ATLAS and CMS results for X → WW * and X → ZZ * decays are compatible with custodial symmetry under both the spin-0 and -2 hypotheses, and that the data expected to become available during 2012 are unlikely to discriminate significantly between these possibilities. (orig.)

HIRFL-SSC trim coil currents calculation by conjugate gradients method

International Nuclear Information System (INIS)

Liu, W.

2005-01-01

For accelerating different kinds of ions to various energies, the HIRFL-SSC should form the corresponding isochronous magnetic field by its main coil and trim coils. Previously, there were errors in fitting the theoretical isochronous magnetic field in the small radius region, which led to some operation difficulties for ion acceleration in the inject region. After further investigation of the restrictive condition of the maximum current limitation, the trim coil currents for fitting the theoretical isochronous magnetic field were recalculated by the conjugate gradients method. Better results were obtained in the operation of HIRFL-SSC. This article introduces the procedure to calculate the trim coil currents. The calculation method of conjugate gradients is introduced and the fitting error is analysed. (author)

Modulational instability development and current drive

International Nuclear Information System (INIS)

Popel, S.I.; Vladimirov, S.V.; Tsytovich, V.N.

1992-01-01

Recently many investigations on current driven by lower-hybrid (LH) waves in a plasma of toroidal nuclear fusion installations are carried out. Usually a theoretical approach taking into account quasilinear and binary collisions effects is used to describe current drive. However a problem of comparison of the results obtained with the aid of the above theoretical approach and experimental data takes place. Namely the experimentally observed currents driven by LH waves is two-three orders of magnitude larger than those calculated. The above discrepancy between theory and experiment is related with the existence of the so-called ''spectral gap'', that is the gap between the parallel phase velocities of LH waves ω/k || (where ω, k || are LH wave frequency and a component of wavenumber k parallel to the external magnetic field) which are necessary for effective Landau damping of LH waves (i.e. velocities as high as several electron thermal velocities) and the lowest parallel phase velocity in the injected LH wave spectrum. Experimentally observed current drive may be explained if one accounts for filling of the ''spectral gap'' by LH waves. Some nonlinear effects have been drawn in current drive description to explain the ''spectral gap'' filling by LH waves. However the LH wave modulational instability (MI) effect has not been considered yet in application to current drive description. The aim of this paper is to investigate this MI influence. We shall show that for sufficiently intensive pump level of LH wave the MI can lead to ''spectral gap'' filling. (author) 4 refs

An automated framework for hypotheses generation using literature

Directory of Open Access Journals (Sweden)

Abedi Vida

2012-08-01

Full Text Available Abstract Background In bio-medicine, exploratory studies and hypothesis generation often begin with researching existing literature to identify a set of factors and their association with diseases, phenotypes, or biological processes. Many scientists are overwhelmed by the sheer volume of literature on a disease when they plan to generate a new hypothesis or study a biological phenomenon. The situation is even worse for junior investigators who often find it difficult to formulate new hypotheses or, more importantly, corroborate if their hypothesis is consistent with existing literature. It is a daunting task to be abreast with so much being published and also remember all combinations of direct and indirect associations. Fortunately there is a growing trend of using literature mining and knowledge discovery tools in biomedical research. However, there is still a large gap between the huge amount of effort and resources invested in disease research and the little effort in harvesting the published knowledge. The proposed hypothesis generation framework (HGF finds “crisp semantic associations” among entities of interest - that is a step towards bridging such gaps. Methodology The proposed HGF shares similar end goals like the SWAN but are more holistic in nature and was designed and implemented using scalable and efficient computational models of disease-disease interaction. The integration of mapping ontologies with latent semantic analysis is critical in capturing domain specific direct and indirect “crisp” associations, and making assertions about entities (such as disease X is associated with a set of factors Z. Results Pilot studies were performed using two diseases. A comparative analysis of the computed “associations” and “assertions” with curated expert knowledge was performed to validate the results. It was observed that the HGF is able to capture “crisp” direct and indirect associations, and provide knowledge

An automated framework for hypotheses generation using literature.

Science.gov (United States)

Abedi, Vida; Zand, Ramin; Yeasin, Mohammed; Faisal, Fazle Elahi

2012-08-29

In bio-medicine, exploratory studies and hypothesis generation often begin with researching existing literature to identify a set of factors and their association with diseases, phenotypes, or biological processes. Many scientists are overwhelmed by the sheer volume of literature on a disease when they plan to generate a new hypothesis or study a biological phenomenon. The situation is even worse for junior investigators who often find it difficult to formulate new hypotheses or, more importantly, corroborate if their hypothesis is consistent with existing literature. It is a daunting task to be abreast with so much being published and also remember all combinations of direct and indirect associations. Fortunately there is a growing trend of using literature mining and knowledge discovery tools in biomedical research. However, there is still a large gap between the huge amount of effort and resources invested in disease research and the little effort in harvesting the published knowledge. The proposed hypothesis generation framework (HGF) finds "crisp semantic associations" among entities of interest - that is a step towards bridging such gaps. The proposed HGF shares similar end goals like the SWAN but are more holistic in nature and was designed and implemented using scalable and efficient computational models of disease-disease interaction. The integration of mapping ontologies with latent semantic analysis is critical in capturing domain specific direct and indirect "crisp" associations, and making assertions about entities (such as disease X is associated with a set of factors Z). Pilot studies were performed using two diseases. A comparative analysis of the computed "associations" and "assertions" with curated expert knowledge was performed to validate the results. It was observed that the HGF is able to capture "crisp" direct and indirect associations, and provide knowledge discovery on demand. The proposed framework is fast, efficient, and robust in

Dynamics and stabilization of peak current-mode controlled buck converter with constant current load

Science.gov (United States)

Leng, Min-Rui; Zhou, Guo-Hua; Zhang, Kai-Tun; Li, Zhen-Hua

2015-10-01

The discrete iterative map model of peak current-mode controlled buck converter with constant current load (CCL), containing the output voltage feedback and ramp compensation, is established in this paper. Based on this model the complex dynamics of this converter is investigated by analyzing bifurcation diagrams and the Lyapunov exponent spectrum. The effects of ramp compensation and output voltage feedback on the stability of the converter are investigated. Experimental results verify the simulation and theoretical analysis. The stability boundary and chaos boundary are obtained under the theoretical conditions of period-doubling bifurcation and border collision. It is found that there are four operation regions in the peak current-mode controlled buck converter with CCL due to period-doubling bifurcation and border-collision bifurcation. Research results indicate that ramp compensation can extend the stable operation range and transfer the operating mode, and output voltage feedback can eventually eliminate the coexisting fast-slow scale instability. Project supported by the National Natural Science Foundation of China (Grant No. 61371033), the Fok Ying-Tung Education Foundation for Young Teachers in the Higher Education Institutions of China (Grant No. 142027), the Sichuan Provincial Youth Science and Technology Fund, China (Grant Nos. 2014JQ0015 and 2013JQ0033), and the Fundamental Research Funds for the Central Universities, China (Grant No. SWJTU11CX029).

Williams Syndrome Hypersociability: A Neuropsychological Study of the Amygdala and Prefrontal Cortex Hypotheses

Science.gov (United States)

Capitao, Liliana; Sampaio, Adriana; Fernandez, Montse; Sousa, Nuno; Pinheiro, Ana; Goncalves, Oscar F.

2011-01-01

Individuals with Williams syndrome display indiscriminate approach towards strangers. Neuroimaging studies conducted so far have linked this social profile to structural and/or functional abnormalities in WS amygdala and prefrontal cortex. In this study, the neuropsychological hypotheses of amygdala and prefrontal cortex involvement in WS…

Toward a Theoretical Model of Decision-Making and Resistance to Change among Higher Education Online Course Designers

Science.gov (United States)

Dodd, Bucky J.

2013-01-01

Online course design is an emerging practice in higher education, yet few theoretical models currently exist to explain or predict how the diffusion of innovations occurs in this space. This study used a descriptive, quantitative survey research design to examine theoretical relationships between decision-making style and resistance to change…

A Case-Study Assignment to Teach Theoretical Perspectives in Abnormal Psychology.

Science.gov (United States)

Perkins, David V.

1991-01-01

Describes an assignment that requires students to organize, prepare, and revise a case study in abnormal behavior. Explains that students employ a single theoretical perspective in preparing a report on a figure from history, literature, the arts, or current events. Discusses the value of the assignment for students. (SG)

Theoretical implications of the resonance anomalies in the e+-e- system

International Nuclear Information System (INIS)

Pakvasa, S.; Rajasekaran, G.; Tuan, S.F.

1975-01-01

The phenomenological properties of the recent resonance anomalies at 3.1 GeV and 3.7 GeV in e + -e - systems are confronted in a fairly systematic way with models presently known to us. These include charm-related models, neutral-intermediate-boson-type hypotheses, gauge-related models, and exotic suggestions that the resonant states may have abnormal C parity or that the electromagnetic current has a color triplet piece. We conclude that none of the schemes proposed represents a really satisfactory interpretation of the data

Joint Czechoslovak-Soviet workshop on current drive in tokamaks

International Nuclear Information System (INIS)

1985-10-01

At the Joint Czechoslovak-Soviet Workshop on Current Drive in Tokamaks, five papers dealing with issues of general interest were presented. In a theoretical paper by Klima and Pavlo a one-dimensional model of the lower-hybrid current drive is described and the results of its analysis are used in a numerical simulation using T-7 tokamak parameters. In the second theoretical paper by Vojtsekhovich, Parail and Pereverzev the influence of the LH wave spectrum on the efficiency of the current drive is studied. Two papers deal with a new microwave system designed for experiments on LHCD in the T-7 tokamak. In particular, the power spectra of new four-waveguide grills are computed. In the last paper the non-inductive start-up of the discharge in the T-7 tokamak by means of electron cyclotron waves is investigated. (J.U.)

Why Be a Shrub? A Basic Model and Hypotheses for the Adaptive Values of a Common Growth Form

Science.gov (United States)

Götmark, Frank; Götmark, Elin; Jensen, Anna M.

2016-01-01

Shrubs are multi-stemmed short woody plants, more widespread than trees, important in many ecosystems, neglected in ecology compared to herbs and trees, but currently in focus due to their global expansion. We present a novel model based on scaling relationships and four hypotheses to explain the adaptive significance of shrubs, including a review of the literature with a test of one hypothesis. Our model describes advantages for a small shrub compared to a small tree with the same above-ground woody volume, based on larger cross-sectional stem area, larger area of photosynthetic tissue in bark and stem, larger vascular cambium area, larger epidermis (bark) area, and larger area for sprouting, and faster production of twigs and canopy. These components form our Hypothesis 1 that predicts higher growth rate for a small shrub than a small tree. This prediction was supported by available relevant empirical studies (14 publications). Further, a shrub will produce seeds faster than a tree (Hypothesis 2), multiple stems in shrubs insure future survival and growth if one or more stems die (Hypothesis 3), and three structural traits of short shrub stems improve survival compared to tall tree stems (Hypothesis 4)—all hypotheses have some empirical support. Multi-stemmed trees may be distinguished from shrubs by more upright stems, reducing bending moment. Improved understanding of shrubs can clarify their recent expansion on savannas, grasslands, and alpine heaths. More experiments and other empirical studies, followed by more elaborate models, are needed to understand why the shrub growth form is successful in many habitats. PMID:27507981

Blind spots of dynamic capabilities: A systems theoretic perspective

Directory of Open Access Journals (Sweden)

Robert Burisch

2016-05-01

Full Text Available Dynamic capabilities remain one of the most popular, but also one of the most controversial topics in current knowledge and innovation research. This study exposes strengths and weaknesses of existing conceptualizations of dynamic capabilities by using a systems theoretic lens. Systems theory suggests that organizations operate in environments they cannot fully understand. Thus, organizational action patterns inevitably involve simplification, selectivity and uncertainty leading to inherent blind spots in every kind of strategic action. As the resulting insight, fully flexible organizational capabilities might not be achievable and continuous adaptation to every kind of environmental change cannot be possible from a systems theoretic perspective. Accordingly, this work discusses empirical difficulties that derive from the preceding argumentation and outlines a corresponding re-conceptualization of the dynamic capabilities concept.

Flux consumption, current ramp-up and current diffusion in Tore Supra non-inductive Lower Hybrid scenarios

International Nuclear Information System (INIS)

Kazarian, F.; Litaudon, X.; Moreau, D.; Arslanbekov, R.; Hoang, G.T.; Joffrin, E.; Peysson, Y.; Allibert, J.P.; Ane, J.M.; Bremond, S.

1995-01-01

The main objective of the Lower Hybrid (LH) experiments performed on Tore Supra is to provide large flux savings for long pulse operation while controlling the plasma current density profile. This goal will be best achieved by applying LH wave directly during the current ramp-up phase. Experiments have been performed where a large fraction of the current is driven non-inductively during the ramp-up phase. A theoretical flux consumption scaling is presented and compared to experimental data. The time evolutions of the current density profiles are analysed with a new current diffusion code (CRONOS). In view to achieve fully non-inductive current drive discharges in a fast, systematic and reproducible way, experiments where the primary voltage is imposed have been carried out. In a complementary approach, an appropriate transformer flux feedback scheme has been also studied. (author) 6 refs.; 6 figs

Current disruption in toroidal devices

International Nuclear Information System (INIS)

1979-07-01

Attempts at raising the density or the plasma current in a tokamak above certain critical values generally result in termination of the discharge by a disruption. This sudden end of the plasma current and plasma confinement is accompanied by large induced voltages and currents in the outer structures which, in large tokamaks, can only be handled with considerable effort, and which will probably only be tolerable in reactors as rare accidents. Because of its crucial importance for the construction and operation of tokamaks, this phenomenon and its theoretical interpretation were the subject of a three-day symposium organized by the International Atomic Energy Agency and Max-Planck-Institut fuer Plasmaphysik at Garching from February 14 to 16. (orig./HT)

Theoretical Analysis of Potential and Current Distributions in Planar Electrodes of Lithium-ion Batteries

International Nuclear Information System (INIS)

Taheri, Peyman; Mansouri, Abraham; Yazdanpour, Maryam; Bahrami, Majid

2014-01-01

An analytical model is proposed to describe the two-dimensional distribution of potential and current in planar electrodes of pouch-type lithium-ion batteries. A concentration-independent polarization expression, obtained experimentally, is used to mimic the electrochemical performance of the battery. By numerically solving the charge balance equation on each electrode in conjugation with the polarization expression, the battery behavior during constant-current discharge processes is simulated. Our numerical simulations show that reaction current between the electrodes remains approximately uniform during most of the discharge process, in particular, when depth-of-discharge varies from 5% to 85%. This observation suggests to simplify the electrochemical behavior of the battery such that the charge balance equation on each electrode can be solved analytically to obtain closed-form solutions for potential and current density distributions. The analytical model shows fair agreement with numerical data at modest computational cost. The model is applicable for both charge and discharge processes, and its application is demonstrated for a prismatic 20 Ah nickel-manganese-cobalt lithium-ion battery during discharge processes

Coping with the Stigma of Mental Illness: Empirically-Grounded Hypotheses from Computer Simulations

Science.gov (United States)

Kroska, Amy; Har, Sarah K.

2011-01-01

This research demonstrates how affect control theory and its computer program, "Interact", can be used to develop empirically-grounded hypotheses regarding the connection between cultural labels and behaviors. Our demonstration focuses on propositions in the modified labeling theory of mental illness. According to the MLT, negative societal…

The Outwardly Rectifying Current of Layer 5 Neocortical Neurons that was Originally Identified as "Non-Specific Cationic" Is Essentially a Potassium Current.

Directory of Open Access Journals (Sweden)

Omer Revah

Full Text Available In whole-cell patch clamp recordings from layer 5 neocortical neurons, blockade of voltage gated sodium and calcium channels leaves a cesium current that is outward rectifying. This current was originally identified as a "non-specific cationic current", and subsequently it was hypothesized that it is mediated by TRP channels. In order to test this hypothesis, we used fluorescence imaging of intracellular sodium and calcium indicators, and found no evidence to suggest that it is associated with influx of either of these ions to the cell body or dendrites. Moreover, the current is still prominent in neurons from TRPC1-/- and TRPC5-/- mice. The effects on the current of various blocking agents, and especially its sensitivity to intracellular tetraethylammonium, suggest that it is not a non-specific cationic current, but rather that it is generated by cesium-permeable delayed rectifier potassium channels.

From themes to hypotheses: following up with quantitative methods.

Science.gov (United States)

Morgan, David L

2015-06-01

One important category of mixed-methods research designs consists of quantitative studies that follow up on qualitative research. In this case, the themes that serve as the results from the qualitative methods generate hypotheses for testing through the quantitative methods. That process requires operationalization to translate the concepts from the qualitative themes into quantitative variables. This article illustrates these procedures with examples that range from simple operationalization to the evaluation of complex models. It concludes with an argument for not only following up qualitative work with quantitative studies but also the reverse, and doing so by going beyond integrating methods within single projects to include broader mutual attention from qualitative and quantitative researchers who work in the same field. © The Author(s) 2015.

Why are there lasting effects from exposure to stress during development? An analysis of current models of early stress.

Science.gov (United States)

Chaby, Lauren E

2016-10-01

The potential for stressful experiences in early life to cause lasting changes in phenotype is well documented, but the functional and evolutionary context of these changes is not well understood. Many hypotheses have been proposed to explain the role of lasting effects of stress exposure during gestation and early development; the purpose of this review is to discuss these hypotheses in the context of human and non-human animal research in the last three decades in order to (i) further dialogues between those approaching early stress from biomedical and evolutionary/ecological perspectives, (ii) outline strengths and limitations of current hypotheses, with respect to species and context-specific effects of exposure to stress in early development, and (iii) address recent evidence suggesting that stress in early development can have beneficial effects in adulthood. It is suggested that the hypotheses discussed are not mutually exclusive, but the applicability of each hypothesis will depend upon the environmental conditions and stability a species, or perhaps even an individual, experiences in their lifetime. Potential investigations to clarify applications of the current hypotheses are discussed, including longitudinal studies that span multiple developmental stages and investigations of species where measures of fitness are possible. Copyright © 2016 Elsevier Inc. All rights reserved.

New Vehicle Detection Method with Aspect Ratio Estimation for Hypothesized Windows

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Jisu Kim

2015-12-01

Full Text Available All kinds of vehicles have different ratios of width to height, which are called the aspect ratios. Most previous works, however, use a fixed aspect ratio for vehicle detection (VD. The use of a fixed vehicle aspect ratio for VD degrades the performance. Thus, the estimation of a vehicle aspect ratio is an important part of robust VD. Taking this idea into account, a new on-road vehicle detection system is proposed in this paper. The proposed method estimates the aspect ratio of the hypothesized windows to improve the VD performance. Our proposed method uses an Aggregate Channel Feature (ACF and a support vector machine (SVM to verify the hypothesized windows with the estimated aspect ratio. The contribution of this paper is threefold. First, the estimation of vehicle aspect ratio is inserted between the HG (hypothesis generation and the HV (hypothesis verification. Second, a simple HG method named a signed horizontal edge map is proposed to speed up VD. Third, a new measure is proposed to represent the overlapping ratio between the ground truth and the detection results. This new measure is used to show that the proposed method is better than previous works in terms of robust VD. Finally, the Pittsburgh dataset is used to verify the performance of the proposed method.

Delinquency and Peer Acceptance in Adolescence: A Within-Person Test of Moffitt's Hypotheses

Science.gov (United States)

Rulison, Kelly L.; Kreager, Derek A.; Osgood, D. Wayne

2014-01-01

We tested 2 hypotheses derived from Moffitt's (1993) taxonomic theory of antisocial behavior, both of which are central to her explanation for the rise in delinquency during adolescence. We tested whether persistently delinquent individuals become more accepted by their peers during adolescence and whether individuals who abstain from delinquent…

Theoretical and experimental investigations of stochastic boundaries in tokamaks

International Nuclear Information System (INIS)

Ghendrih, Ph.; Grosman, A.; Capes, H.

1996-01-01

The physics of stochastic boundaries are reviewed. The stochastic properties of magnetic field lines are recalled and related to the spectrum of the radial magnetic perturbation. The stochastic region, referred to as the divertor volume, is shown to be bounded to the edge plasma. Theoretical predictions for the transport of energy, current and particles in the divertor volume are analysed for both the laminar and ergodic regimes. (K.A.)

How doctors generate diagnostic hypotheses: a study of radiological diagnosis with functional magnetic resonance imaging.

Directory of Open Access Journals (Sweden)

Marcio Melo

Full Text Available In medical practice, diagnostic hypotheses are often made by physicians in the first moments of contact with patients; sometimes even before they report their symptoms. We propose that generation of diagnostic hypotheses in this context is the result of cognitive processes subserved by brain mechanisms that are similar to those involved in naming objects or concepts in everyday life.To test this proposal we developed an experimental paradigm with functional magnetic resonance imaging (fMRI using radiological diagnosis as a model. Twenty-five radiologists diagnosed lesions in chest X-ray images and named non-medical targets (animals embedded in chest X-ray images while being scanned in a fMRI session. Images were presented for 1.5 seconds; response times (RTs and the ensuing cortical activations were assessed. The mean response time for diagnosing lesions was 1.33 (SD ±0.14 seconds and 1.23 (SD ±0.13 seconds for naming animals. 72% of the radiologists reported cogitating differential diagnoses during trials (3.5 seconds. The overall pattern of cortical activations was remarkably similar for both types of targets. However, within the neural systems shared by both stimuli, activation was significantly greater in left inferior frontal sulcus and posterior cingulate cortex for lesions relative to animals.Generation of diagnostic hypotheses and differential diagnoses made through the immediate visual recognition of clinical signs can be a fast and automatic process. The co-localization of significant brain activation for lesions and animals suggests that generating diagnostic hypotheses for lesions and naming animals are served by the same neuronal systems. Nevertheless, diagnosing lesions was cognitively more demanding and associated with more activation in higher order cortical areas. These results support the hypothesis that medical diagnoses based on prompt visual recognition of clinical signs and naming in everyday life are supported by similar

Fast wave current drive on DIII-D

International Nuclear Information System (INIS)

deGrassie, J.S.; Petty, C.C.; Pinsker, R.I.; Forest, C.B.; Ikezi, H.; Prater, R.; Baity, F.W.; Callis, R.W.; Cary, W.P.; Chiu, S.C.; Doyle, E.J.; Ferguson, S.W.; Hoffman, D.J.; Jaeger, E.F.; Kim, K.W.; Lee, J.H.; Lin-Liu, Y.R.; Murakami, M.; ONeill, R.C.; Porkolab, M.; Rhodes, T.L.; Swain, D.W.

1996-01-01

The physics of electron heating and current drive with the fast magnetosonic wave has been demonstrated on DIII-D, in reasonable agreement with theoretical modeling. A recently completed upgrade to the fast wave capability should allow full noninductive current drive in steady state advanced confinement discharges and provide some current density profile control for the Advanced Tokamak Program. DIII-D now has three four-strap fast wave antennas and three transmitters, each with nominally 2 MW of generator power. Extensive experiments have been conducted with the first system, at 60 MHz, while the two newer systems have come into operation within the past year. The newer systems are configured for 60 to 120 MHz. The measured FWCD efficiency is found to increase linearly with electron temperature as γ=0.4x10 18 T e0 (keV) [A/m 2 W], measured up to central electron temperature over 5 keV. A newly developed technique for determining the internal noninductive current density profile gives efficiencies in agreement with this scaling and profiles consistent with theoretical predictions. Full noninductive current drive at 170 kA was achieved in a discharge prepared by rampdown of the Ohmic current. Modulation of microwave reflectometry signals at the fast wave frequency is being used to investigate fast wave propagation and damping. Additionally, rf pick-up probes on the internal boundary of the vessel provide a comparison with ray tracing codes, with clear evidence for a toroidally directed wave with antenna phasing set for current drive. copyright 1996 American Institute of Physics

Converging Paradigms: A Reflection on Parallel Theoretical Developments in Psychoanalytic Metapsychology and Empirical Dream Research.

Science.gov (United States)

Schmelowszky, Ágoston

2016-08-01

In the last decades one can perceive a striking parallelism between the shifting perspective of leading representatives of empirical dream research concerning their conceptualization of dreaming and the paradigm shift within clinically based psychoanalytic metapsychology with respect to its theory on the significance of dreaming. In metapsychology, dreaming becomes more and more a central metaphor of mental functioning in general. The theories of Klein, Bion, and Matte-Blanco can be considered as milestones of this paradigm shift. In empirical dream research, the competing theories of Hobson and of Solms respectively argued for and against the meaningfulness of the dream-work in the functioning of the mind. In the meantime, empirical data coming from various sources seemed to prove the significance of dream consciousness for the development and maintenance of adaptive waking consciousness. Metapsychological speculations and hypotheses based on empirical research data seem to point in the same direction, promising for contemporary psychoanalytic practice a more secure theoretical base. In this paper the author brings together these diverse theoretical developments and presents conclusions regarding psychoanalytic theory and technique, as well as proposing an outline of an empirical research plan for testing the specificity of psychoanalysis in developing dream formation.

Exploration of miRNA families for hypotheses generation.

KAUST Repository

Kamanu, T.K.

2013-10-15

Technological improvements have resulted in increased discovery of new microRNAs (miRNAs) and refinement and enrichment of existing miRNA families. miRNA families are important because they suggest a common sequence or structure configuration in sets of genes that hint to a shared function. Exploratory tools to enhance investigation of characteristics of miRNA families and the functions of family-specific miRNA genes are lacking. We have developed, miRNAVISA, a user-friendly web-based tool that allows customized interrogation and comparisons of miRNA families for hypotheses generation, and comparison of per-species chromosomal distribution of miRNA genes in different families. This study illustrates hypothesis generation using miRNAVISA in seven species. Our results unveil a subclass of miRNAs that may be regulated by genomic imprinting, and also suggest that some miRNA families may be species-specific, as well as chromosome- and/or strand-specific.

Theoretical and experimental studies of the magnetic fields of Rotamak discharge

International Nuclear Information System (INIS)

Kirolous, H.

1986-12-01

In part I of this thesis, the self-generated bi-directional toroidal magnetic field structure which has been observed to exist in previous rotamak discharges is theoretically investigated. A possible explanation for the existence of this self-generated field, which relies on the presence of screening currents in the plasma, is advanced. Experimental studies of the magnetic field structure of a rotamak plasma configuration generated and sustained in a metal discharge vessel by means of a rotating magnetic field are described in part II. The rotating magnetic field was produced by feeding radio frequency (r.f.) currents, dephased by 90 degrees, through two orthogonal coils which were located inside the metal chamber. High power amplifiers were used to supply the r.f. current pulses. The efficiency of the r.f. power transfer to the plasma was maximized by using impedance matching networks. The effect on the rotating magnetic field of eddy currents induced in the conducting vessel has been theoretically and experimentally investigated. Extensive magnetic field measurements have been undertaken on one particular rotamak discharge. Measurements of the penetration of the rotating magnetic field into the plasma were made at various axial positions. The steady magnetic field structure was measured at a matrix of 2640 points and a two dimensional least square polynomial fitting algorithm was used to smooth the measured data. This fitting procedure enabled reliable plots of the poloidal flux and current density contours to be constructed. An attempt has been made to apply MHD equilibrium theory to the observed plasma/field configuration. 23 refs., 99 figs., ills

Valley current characterization of high current density resonant tunnelling diodes for terahertz-wave applications

Science.gov (United States)

Jacobs, K. J. P.; Stevens, B. J.; Baba, R.; Wada, O.; Mukai, T.; Hogg, R. A.

2017-10-01

We report valley current characterisation of high current density InGaAs/AlAs/InP resonant tunnelling diodes (RTDs) grown by metal-organic vapour phase epitaxy (MOVPE) for THz emission, with a view to investigate the origin of the valley current and optimize device performance. By applying a dual-pass fabrication technique, we are able to measure the RTD I-V characteristic for different perimeter/area ratios, which uniquely allows us to investigate the contribution of leakage current to the valley current and its effect on the PVCR from a single device. Temperature dependent (20 - 300 K) characteristics for a device are critically analysed and the effect of temperature on the maximum extractable power (PMAX) and the negative differential conductance (NDC) of the device is investigated. By performing theoretical modelling, we are able to explore the effect of typical variations in structural composition during the growth process on the tunnelling properties of the device, and hence the device performance.

STRUCTURAL AND METHODICAL MODEL OF INCREASING THE LEVEL OF THEORETICAL TRAINING OF CADETS USING INFORMATION AND COMMUNICATION TECHNOLOGIES

Directory of Open Access Journals (Sweden)

Vladislav V. Bulgakov

2018-03-01

Full Text Available Features of training in higher educational institutions of system of EMERCOM of Russia demand introduction of the new educational techniques and the technical means directed on intensification of educational process, providing an opportunity of preparation of cadets at any time in the independent mode and improving quality of their theoretical knowledge. The authors have developed a structural and methodological model of increasing the level of theoretical training of cadets using information and communication technologies. The proposed structural and methodological model that includes elements to stimulate and enhance cognitive activity, allows you to generate the trajectory of theoretical training of cadets for the entire period of study at the University, to organize a systematic independent work, objective, current and final control of theoretical knowledge. The structural and methodological model for improving the level of theoretical training consists of three main elements: the base of theoretical questions, functional modules "teacher" and "cadet". The basis of the structural and methodological model of increasing the level of theoretical training of cadets is the base of theoretical issues, developed in all disciplines specialty 20.05.01 – fire safety. The functional module "teacher" allows you to create theoretical questions of various kinds, edit questions and delete them from the database if necessary, as well as create tests and monitor their implementation. The functional module "cadet" provides ample opportunities for theoretical training through independent work, testing for current and final control, the implementation of the game form of training in the form of a duel, as well as for the formation of the results of the cadets in the form of statistics and rankings. Structural and methodical model of increasing the level of theoretical training of cadets is implemented in practice in the form of a multi-level automated system

Theoretical and computational analyses of LNG evaporator

Science.gov (United States)

Chidambaram, Palani Kumar; Jo, Yang Myung; Kim, Heuy Dong

2017-04-01

Theoretical and numerical analysis on the fluid flow and heat transfer inside a LNG evaporator is conducted in this work. Methane is used instead of LNG as the operating fluid. This is because; methane constitutes over 80% of natural gas. The analytical calculations are performed using simple mass and energy balance equations. The analytical calculations are made to assess the pressure and temperature variations in the steam tube. Multiphase numerical simulations are performed by solving the governing equations (basic flow equations of continuity, momentum and energy equations) in a portion of the evaporator domain consisting of a single steam pipe. The flow equations are solved along with equations of species transport. Multiphase modeling is incorporated using VOF method. Liquid methane is the primary phase. It vaporizes into the secondary phase gaseous methane. Steam is another secondary phase which flows through the heating coils. Turbulence is modeled by a two equation turbulence model. Both the theoretical and numerical predictions are seen to match well with each other. Further parametric studies are planned based on the current research.

Skin stem cell hypotheses and long term clone survival--explored using agent-based modelling.

Science.gov (United States)

Li, X; Upadhyay, A K; Bullock, A J; Dicolandrea, T; Xu, J; Binder, R L; Robinson, M K; Finlay, D R; Mills, K J; Bascom, C C; Kelling, C K; Isfort, R J; Haycock, J W; MacNeil, S; Smallwood, R H

2013-01-01

Epithelial renewal in skin is achieved by the constant turnover and differentiation of keratinocytes. Three popular hypotheses have been proposed to explain basal keratinocyte regeneration and epidermal homeostasis: 1) asymmetric division (stem-transit amplifying cell); 2) populational asymmetry (progenitor cell with stochastic fate); and 3) populational asymmetry with stem cells. In this study, we investigated lineage dynamics using these hypotheses with a 3D agent-based model of the epidermis. The model simulated the growth and maintenance of the epidermis over three years. The offspring of each proliferative cell was traced. While all lineages were preserved in asymmetric division, the vast majority were lost when assuming populational asymmetry. The third hypothesis provided the most reliable mechanism for self-renewal by preserving genetic heterogeneity in quiescent stem cells, and also inherent mechanisms for skin ageing and the accumulation of genetic mutation.

Current efficiency in the chlorate cell process

Directory of Open Access Journals (Sweden)

Spasojević Miroslav D.

2014-01-01

Full Text Available A mathematical model has been set up for current efficiency in a chlorate cell acting as an ideal electrochemical tubular reactor with a linear increase in hypochlorite concentration from the entrance to the exit. Good agreement was found between the results on current efficiency experimentally obtained under simulated industrial chlorate production conditions and the theoretical values provided by the mathematical model. [Projekat Ministarstva nauke Republike Srbije, br. 172057 i br. 172062

As the climatic disasters came. Hydrogen world view contra inflation of hypotheses; Als die Klimakatastrophen kamen. Wasserstoff-Weltbild kontra Hypothesen-Inflation

Energy Technology Data Exchange (ETDEWEB)

Gottfried, Rudolf J.

2009-07-01

The author of the contribution under consideration addresses to all persons which are interested scientifically and also are ready for leaving the well-trodden paths of conventional conceptions occasionally if it is shown that the paths mislead when continuing. In particular, here it is a matter of the controversy of the hydrogen conception of the world against hypothesis inflation. This book does not set up new hypotheses which are arranged in the numerously existing hypotheses according to the picture of the world. It is time to deliver the secured facts from the crusts of rigid hypotheses in order to look for new realizations without prejudices and in order to arrange the hypotheses meaningfully.

New Observational Tools and Datasources for Hydrology : Hydrological data Unlocked by Tinkering

NARCIS (Netherlands)

Hut, R.W.

2013-01-01

Advances in scientific understanding follow a cyclic pattern where new observational techniques lead to novel theoretical insight. From novel theories, in turn, hypotheses are derived that cannot be tested using current observations and thus create a demand for even newer observational techniques.

An Experimental and Theoretical High Energy Physics Program

Energy Technology Data Exchange (ETDEWEB)

Shipsey, Ian

2012-07-31

The Purdue High Energy Physics Group conducts research in experimental and theoretical elementary particle physics and experimental high energy astrophysics. Our goals, which we share with high energy physics colleagues around the world, are to understand at the most fundamental level the nature of matter, energy, space and time, and in order to explain the birth, evolution and fate of the Universe. The experiments in which we are currently involved are: CDF, CLEO-c, CMS, LSST, and VERITAS. We have been instrumental in establishing two major in-house facilities: The Purdue Particle Physics Microstructure Detector Facility (P3MD) in 1995 and the CMS Tier-2 center in 2005. The research efforts of the theory group span phenomenological and theoretical aspects of the Standard Model as well as many of its possible extensions. Recent work includes phenomenological consequences of supersymmetric models, string theory and applications of gauge/gravity duality, the cosmological implications of massive gravitons, and the physics of extra dimensions.

Theoretical model for plasma expansion generated by hypervelocity impact

International Nuclear Information System (INIS)

Ju, Yuanyuan; Zhang, Qingming; Zhang, Dongjiang; Long, Renrong; Chen, Li; Huang, Fenglei; Gong, Zizheng

2014-01-01

The hypervelocity impact experiments of spherical LY12 aluminum projectile diameter of 6.4 mm on LY12 aluminum target thickness of 23 mm have been conducted using a two-stage light gas gun. The impact velocity of the projectile is 5.2, 5.7, and 6.3 km/s, respectively. The experimental results show that the plasma phase transition appears under the current experiment conditions, and the plasma expansion consists of accumulation, equilibrium, and attenuation. The plasma characteristic parameters decrease as the plasma expands outward and are proportional with the third power of the impact velocity, i.e., (T e , n e ) ∝ v p 3 . Based on the experimental results, a theoretical model on the plasma expansion is developed and the theoretical results are consistent with the experimental data

Theoretical model for plasma expansion generated by hypervelocity impact

Energy Technology Data Exchange (ETDEWEB)

Ju, Yuanyuan; Zhang, Qingming, E-mail: qmzhang@bit.edu.cn; Zhang, Dongjiang; Long, Renrong; Chen, Li; Huang, Fenglei [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China); Gong, Zizheng [National Key Laboratory of Science and Technology on Reliability and Environment Engineering, Beijing Institute of Spacecraft Environment Engineering, Beijing 100094 (China)

2014-09-15

The hypervelocity impact experiments of spherical LY12 aluminum projectile diameter of 6.4 mm on LY12 aluminum target thickness of 23 mm have been conducted using a two-stage light gas gun. The impact velocity of the projectile is 5.2, 5.7, and 6.3 km/s, respectively. The experimental results show that the plasma phase transition appears under the current experiment conditions, and the plasma expansion consists of accumulation, equilibrium, and attenuation. The plasma characteristic parameters decrease as the plasma expands outward and are proportional with the third power of the impact velocity, i.e., (T{sub e}, n{sub e}) ∝ v{sub p}{sup 3}. Based on the experimental results, a theoretical model on the plasma expansion is developed and the theoretical results are consistent with the experimental data.

Theoretical analysis on ac loss properties of two-strand parallel conductors composed of superconducting multifilamentary strands

CERN Document Server

Iwakuma, M; Funaki, K

2002-01-01

The ac loss properties of two-strand parallel conductors composed of superconducting multifilamentary strands were theoretically investigated. The constituent strands generally need to be insulated and transposed for the sake of uniform current distribution and low ac loss. In case the transposition points deviate from the optimum ones, shielding current is induced according to the interlinkage magnetic flux of the twisted loop enclosed by the insulated strands and the contact resistances at the terminals. It produces an additional ac loss. Supposing a simple situation where a two-strand parallel conductor with one-point transposition is exposed to a uniform ac magnetic field, the basic equations for the magnetic field were proposed and the theoretical expressions of the additional ac losses derived. As a result, the following features were shown. The additional ac loss in the non-saturation case, where the induced shielding current is less than the critical current of a strand, is proportional to the square ...

Towards A Theoretical Biology: Reminiscences

Indian Academy of Sciences (India)

engaged in since the start of my career at the University of Chicago. Theoretical biology was ... research on theoretical problems in biology. Waddington, an ... aimed at stimulating the development of such a theoretical biology. The role the ...

An in-depth analysis of theoretical frameworks for the study of care coordination

Directory of Open Access Journals (Sweden)

Sabine Van Houdt

2013-06-01

Full Text Available Introduction: Complex chronic conditions often require long-term care from various healthcare professionals. Thus, maintaining quality care requires care coordination. Concepts for the study of care coordination require clarification to develop, study and evaluate coordination strategies. In 2007, the Agency for Healthcare Research and Quality defined care coordination and proposed five theoretical frameworks for exploring care coordination. This study aimed to update current theoretical frameworks and clarify key concepts related to care coordination. Methods: We performed a literature review to update existing theoretical frameworks. An in-depth analysis of these theoretical frameworks was conducted to formulate key concepts related to care coordination.Results: Our literature review found seven previously unidentified theoretical frameworks for studying care coordination. The in-depth analysis identified fourteen key concepts that the theoretical frameworks addressed. These were ‘external factors’, ‘structure’, ‘tasks characteristics’, ‘cultural factors’, ‘knowledge and technology’, ‘need for coordination’, ‘administrative operational processes’, ‘exchange of information’, ‘goals’, ‘roles’, ‘quality of relationship’, ‘patient outcome’, ‘team outcome’, and ‘(interorganizational outcome’.Conclusion: These 14 interrelated key concepts provide a base to develop or choose a framework for studying care coordination. The relational coordination theory and the multi-level framework are interesting as these are the most comprehensive.

Practical versus theoretical domestic energy consumption for space heating

International Nuclear Information System (INIS)

Audenaert, A.; Briffaerts, K.; Engels, L.

2011-01-01

Methods to calculate the theoretical energy consumption consider several things: the number of degree days per year that need to be compensated by heating, the characteristics of the dwelling, the number of occupants and the characteristics of the installation for space heating and sanitary hot water. However, these methods do not take into account consumer behaviour, which may affect the actual consumption. The theoretical calculation methods are based on assumptions and use a number of standardized parameters. The difference between the actual and the theoretical energy consumption, and the impact of the residents' behaviour on energy consumption, is analysed by means of a literature study and a practical research. An energy advice procedure (EAP) audit is executed in five dwellings, as well as a survey regarding the energy related behaviour of the households. The theoretically calculated consumption is compared with the billed actual energy consumption of the families. The results show some problems with the current procedure and give some options to improve it. Some research needs are identified to gain more insights in the influence of different behavioural factors on the actual energy use for heating. - Highlights: → The energy advice procedure (EAP) calculates the energy use for heating in dwellings. → Calculations are compared with the real energy use for 5 dwellings. → A survey on the occupants' behaviour is used to interpret the observed differences. → Default values used in the EAP can be very different from the observed behaviour.

Practical versus theoretical domestic energy consumption for space heating

Energy Technology Data Exchange (ETDEWEB)

Audenaert, A., E-mail: amaryllis.audenaert@artesis.be [Department of Applied Engineering: Construction, Artesis University College of Antwerp, Paardenmarkt 92, B-2000 Antwerp (Belgium); Department of Environment, Technology and Technology Management, University of Antwerp, Prinsstraat 13, B-2000 Antwerp (Belgium); Briffaerts, K. [Unit Transition Energy and Environment, VITO NV, Boeretang 200, B-2400 Mol (Belgium); Engels, L. [Department of Applied Engineering: Construction, Artesis University College of Antwerp, Paardenmarkt 92, B-2000 Antwerp (Belgium)

2011-09-15

Methods to calculate the theoretical energy consumption consider several things: the number of degree days per year that need to be compensated by heating, the characteristics of the dwelling, the number of occupants and the characteristics of the installation for space heating and sanitary hot water. However, these methods do not take into account consumer behaviour, which may affect the actual consumption. The theoretical calculation methods are based on assumptions and use a number of standardized parameters. The difference between the actual and the theoretical energy consumption, and the impact of the residents' behaviour on energy consumption, is analysed by means of a literature study and a practical research. An energy advice procedure (EAP) audit is executed in five dwellings, as well as a survey regarding the energy related behaviour of the households. The theoretically calculated consumption is compared with the billed actual energy consumption of the families. The results show some problems with the current procedure and give some options to improve it. Some research needs are identified to gain more insights in the influence of different behavioural factors on the actual energy use for heating. - Highlights: > The energy advice procedure (EAP) calculates the energy use for heating in dwellings. > Calculations are compared with the real energy use for 5 dwellings. > A survey on the occupants' behaviour is used to interpret the observed differences. > Default values used in the EAP can be very different from the observed behaviour.

Generalized Weyl modules for twisted current algebras

Science.gov (United States)

Makedonskyi, I. A.; Feigin, E. B.

2017-08-01

We introduce the notion of generalized Weyl modules for twisted current algebras. We study their representation-theoretic and combinatorial properties and also their connection with nonsymmetric Macdonald polynomials. As an application, we compute the dimension of the classical Weyl modules in the remaining unknown case.

Theoretical Physics Division

International Nuclear Information System (INIS)

This report is a survey of the studies done in the Theoretical Physics Division of the Nuclear Physics Institute; the subjects studied in theoretical nuclear physics were the few-nucleon problem, nuclear structure, nuclear reactions, weak interactions, intermediate energy and high energy physics. In this last field, the subjects studied were field theory, group theory, symmetry and strong interactions [fr

Theoretical currents of Archival Science

Directory of Open Access Journals (Sweden)

Carlos Alberto Ávila Araújo

2013-08-01

Full Text Available Archival Science was formed, as a scientific discipline, in the late nineteenth century, from the consolidation of a custody and heritage model. In the twentieth century, several theories have been developed, systematized in this article in four axes. As a result, Archival Science has expanded its scope of studies. As a result of this expansion, there are contemporary perspectives with systemic models, covering different types of archives, concerned with the sociocultural context of the archives, and also insering digital technologies in the practice of archives.

Harmonic and reactive behavior of the quasiparticle tunnel current in SIS junctions

Energy Technology Data Exchange (ETDEWEB)

Rashid, H., E-mail: hawal@chalmers.se; Desmaris, V.; Pavolotsky, A.; Belitsky, V. [Group for Advanced Receiver Development, Earth and Space Sciences Department, Chalmers University of Technology, Gothenburg, 412 96 (Sweden)

2016-04-15

In this paper, we show theoretically and experimentally that the reactive quasiparticle tunnel current of the superconductor tunnel junction could be directly measured at specific bias voltages for the higher harmonics of the quasiparticle tunnel current. We used the theory of quasiparticle tunneling to study the higher harmonics of the quasiparticle tunnel current in superconducting tunnel junction in the presence of rf irradiation. The impact of the reactive current on the harmonic behavior of the quasiparticle tunnel current was carefully studied by implementing a practical model with four parameters to model the dc I-V characteristics of the superconducting tunnel junction. The measured reactive current at the specific bias voltage is in good agreement with our theoretically calculated reactive current through the Kramers-Kronig transform. This study also shows that there is an excellent correspondence between the behavior of the predicted higher harmonics using the previously established theory of quasiparticle tunnel current in superconducting tunnel junctions by J.R. Tucker and M.J. Feldman and the measurements presented in this paper.

Harmonic and reactive behavior of the quasiparticle tunnel current in SIS junctions

International Nuclear Information System (INIS)

Rashid, H.; Desmaris, V.; Pavolotsky, A.; Belitsky, V.

2016-01-01

In this paper, we show theoretically and experimentally that the reactive quasiparticle tunnel current of the superconductor tunnel junction could be directly measured at specific bias voltages for the higher harmonics of the quasiparticle tunnel current. We used the theory of quasiparticle tunneling to study the higher harmonics of the quasiparticle tunnel current in superconducting tunnel junction in the presence of rf irradiation. The impact of the reactive current on the harmonic behavior of the quasiparticle tunnel current was carefully studied by implementing a practical model with four parameters to model the dc I-V characteristics of the superconducting tunnel junction. The measured reactive current at the specific bias voltage is in good agreement with our theoretically calculated reactive current through the Kramers-Kronig transform. This study also shows that there is an excellent correspondence between the behavior of the predicted higher harmonics using the previously established theory of quasiparticle tunnel current in superconducting tunnel junctions by J.R. Tucker and M.J. Feldman and the measurements presented in this paper.

"On Clocks and Clouds:" Confirming and Interpreting Climate Models as Scientific Hypotheses (Invited)

Science.gov (United States)

Donner, L.

2009-12-01

The certainty of climate change projected under various scenarios of emissions using general circulation models is an issue of vast societal importance. Unlike numerical weather prediction, a problem to which general circulation models are also applied, projected climate changes usually lie outside of the range of external forcings for which the models generating these changes have been directly evaluated. This presentation views climate models as complex scientific hypotheses and thereby frames these models within a well-defined process of both advancing scientific knowledge and recognizing its limitations. Karl Popper's Logik der Forschung (The Logic of Scientific Discovery, 1934) and 1965 essay “On Clocks and Clouds” capture well the methodologies and challenges associated with constructing climate models. Indeed, the process of a problem situation generating tentative theories, refined by error elimination, characterizes aptly the routine of general circulation model development. Limitations on certainty arise from the distinction Popper perceived in types of natural processes, which he exemplified by clocks, capable of exact measurement, and clouds, subject only to statistical approximation. Remarkably, the representation of clouds in general circulation models remains the key uncertainty in understanding atmospheric aspects of climate change. The asymmetry of hypothesis falsification by negation and much vaguer development of confidence in hypotheses consistent with some of their implications is an important practical challenge to confirming climate models. The presentation will discuss the ways in which predictions made by climate models for observable aspects of the present and past climate can be regarded as falsifiable hypotheses. The presentation will also include reasons why “passing” these tests does not provide complete confidence in predictions about the future by climate models. Finally, I will suggest that a “reductionist” view, in

Teaching the fluctuation test in silico by using mutate: a program to distinguish between the adaptive and spontaneous mutation hypotheses.

Science.gov (United States)

Carvajal-Rodríguez, Antonio

2012-07-01

Mutate is a program developed for teaching purposes to impart a virtual laboratory class for undergraduate students of Genetics in Biology. The program emulates the so-called fluctuation test whose aim is to distinguish between spontaneous and adaptive mutation hypotheses in bacteria. The plan is to train students in certain key multidisciplinary aspects of current genetics such as sequence databases, DNA mutations, and hypothesis testing, while introducing the fluctuation test. This seminal experiment was originally performed studying Escherichia coli resistance to the infection by bacteriophage T1. The fluctuation test initiated the modern bacterial genetics that 25 years later ushered in the era of the recombinant DNA. Nowadays we know that some deletions in fhuA, the gene responsible for E. coli membrane receptor of T1, could cause the E. coli resistance to this phage. For the sake of simplicity, we will introduce the assumption that a single mutation generates the resistance to T1. During the practical, the students use the program to download some fhuA gene sequences, manually introduce some stop codon mutations, and design a fluctuation test to obtain data for distinguishing between preadaptative (spontaneous) and induced (adaptive) mutation hypotheses. The program can be launched from a browser or, if preferred, its executable file can be downloaded from http://webs.uvigo.es/acraaj/MutateWeb/Mutate.html. It requires the Java 5.0 (or higher) Runtime Environment (freely available at http://www.java.com). Copyright © 2012 Wiley Periodicals, Inc.

Theoretical Beliefs and Instructional Practices Used for Teaching Spelling in Elementary Classrooms

Science.gov (United States)

McNeill, Brigid; Kirk, Cecilia

2014-01-01

The current study aimed to examine teachers' reported spelling assessment and instruction practices. Analysis of the match between teachers' theoretical beliefs about spelling and their reported pedagogy was conducted to elucidate factors that may support or impede the use of evidence-based teaching strategies in the classroom. An electronic…

A theoretical and experimental analysis of modulated laser fields and power spectra

DEFF Research Database (Denmark)

Olesen, Henning; Jacobsen, G.

1982-01-01

A general theoretical description of modulated laser fields and power spectra for a current modulated single-mode laser is derived, taking into account both the intensity and frequency modulation (IM and FM) of the emitted light. The theory relies on an explicit knowledge of the modulus as well...

Theoretical nuclear structure and astrophysics at FAIR

International Nuclear Information System (INIS)

Rodríguez, Tomás R

2014-01-01

Next generation of radioactive ion beam facilities like FAIR will open a bright future for nuclear structure and nuclear astrophysics research. In particular, very exotic nuclei (mainly neutron rich) isotopes will be produced and a lot of new exciting experimental data will help to test and improve the current nuclear models. In addition, these data (masses, reaction cross sections, beta decay half-lives, etc.) combined with the development of better theoretical approaches will be used as the nuclear physics input for astrophysical simulations. In this presentation I will review some of the state-of-the-art nuclear structure methods and their applications.

Message and source factors, market uncertainty and extrafunctional information processing : hypotheses and empirical evidence

NARCIS (Netherlands)

Song, X.M.

2001-01-01

This article examines how the perceived quality of extrafunctional information improves the innovation management process and contributes to success with innovations. Data collected from 420 Japanese managers and 270 US managers are used to test hypotheses about the antecedents of satisfaction with

Experimental tests and theoretical predictions for electroweak processes

International Nuclear Information System (INIS)

Martinelli, G.; Istituto Nazionale di Fisica Nucleare, Frascati

1987-01-01

In sect. 2, I will briefly recall the basic ingredients of the standard model and I will define the relevant parameters. Low-energy processes which enter into the determination of neutral-current couplings to fermions (in particular sin 2 θ W ) are presented in sect. 3. Radiative corrections to these processes are discussed in sect. 4. In sect. 5 the measurements of the W and Z 0 masses at the SPS collider are described and compared with theoretical predictions including one-loop radiative corrections. (orig./BBO)

Empirical and theoretical challenges in aboveground-belowground ecology

DEFF Research Database (Denmark)

W.H. van der Putten,; R.D. Bardgett; P.C. de Ruiter

2009-01-01

of the current conceptual succession models into more predictive models can help targeting empirical studies and generalising their results. Then, we discuss how understanding succession may help to enhance managing arable crops, grasslands and invasive plants, as well as provide insights into the effects...... and environmental settings, we explore where and how they can be supported by theoretical approaches to develop testable predictions and to generalise empirical results. We review four key areas where a combined aboveground-belowground approach offers perspectives for enhancing ecological understanding, namely...

Differences between previously married and never married 'gay' men: family background, childhood experiences and current attitudes.

Science.gov (United States)

Higgins, Daryl J

2004-01-01

Despite a large body of literature on the development of sexual orientation, little is known about why some gay men have been (or remain) married to a woman. In the current study, a self-selected sample of 43 never married gay men ('never married') and 26 gay men who were married to a woman ('previously married') completed a self-report questionnaire. Hypotheses were based on five possible explanations for gay men's marriages: (a) differences in sexual orientation (i.e., bisexuality); (b) internalized homophobia; (c) religious intolerance; (d) confusion created because of childhood/adolescent sexual experiences; and/or (e) poor psychological adjustment. Previously married described their families' religious beliefs as more fundamentalist than never married. No differences were found between married' and never married' ratings of their sexual orientation and identity, and levels of homophobia and self-depreciation. Family adaptability and family cohesion and the degree to which respondents reported having experienced child maltreatment did not distinguish between previously married and never married. The results highlight how little is understood of the reasons why gay men marry, and the need to develop an adequate theoretical model.

Proposal of a social alliance success model from a relationship marketing perspective: A meta-analytical study of the theoretical foundations

Directory of Open Access Journals (Sweden)

María Jesús Barroso-Méndez

2015-07-01

Full Text Available Partnerships between businesses and non-governmental organizations (NGOs have become widely adopted mechanisms for collaboration in addressing complex social issues, the aim being to take advantage of the two types of organizational rationale to generate mutual value. Many such alliances have proved to be unsuccessful, however. To assist managers improve the likelihood of success of their collaborative relationships, the authors propose a success model of business-NGO partnering processes based on Relationship Marketing Theory. They also analyse the theoretical bases of the model's hypotheses through a meta-analytical study of the existing literature.

Fast wave current drive on DIII-D

International Nuclear Information System (INIS)

deGrassie, J.S.; Petty, C.C.; Pinsker, R.I.

1995-01-01

The physics of electron heating and current drive with the fast magnetosonic wave has been demonstrated on DIII-D, in reasonable agreement with theoretical modeling. A recently completed upgrade to the fast wave capability should allow full noninductive current drive in steady state advanced confinement discharges and provide some current density profile control for the Advanced Tokamak Program. DIII-D now has three four-strap fast wave antennas and three transmitters, each with nominally 2 MW of generator power. Extensive experiments have been conducted with the first system, at 60 MHz, while the two newer systems have come into operation within the past year. The newer systems are configured for 60 to 120 MHz. The measured FWCD efficiency is found to increase linearly with electron temperature as γ = 0.4 x 10 18 T eo (keV) [A/m 2 W], measured up to central electron temperature over 5 keV. A newly developed technique for determining the internal noninductive current density profile gives efficiencies in agreement with this scaling and profiles consistent with theoretical predictions. Full noninductive current drive at 170 kA was achieved in a discharge prepared by rampdown of the Ohmic current. Modulation of microwave reflectometry signals at the fast wave frequency is being used to investigate fast wave propagation and damping. Additionally, rf pick-up probes on the internal boundary of the vessel provide a comparison with ray tracing codes, with dear evidence for a toroidally directed wave with antenna phasing set for current drive. There is some experimental evidence for fast wave absorption by energetic beam ions at high cyclotron harmonic resonances

Buck-Boost Current-Source Inverters With Diode-Inductor Network

DEFF Research Database (Denmark)

Gao, Feng; Liang, Chao; Loh, Poh Chiang

2009-01-01

This paper presents a number of novel currentsource inverters (CSIs) with enhanced current buck-boost capability. By adding a unique diode-inductor network between the inverter circuitry and current-boost elements, the proposed buck-boost CSIs demonstrate a doubling of current-boost capability......, as compared with other recently reported buck-boost CSIs. For controlling the proposed CSIs, two modulation schemes are designed for achieving either optimized harmonic performance or minimized commutation count without influencing the inverter current buck-boost gain. These theoretical findings were...

Current limiting capability of diffused resistors

International Nuclear Information System (INIS)

Shedd, W.; Cappelli, J.

1979-01-01

An experimental evaluation of the current limiting capability of dielectrically isolated diffused resistors at transient ionizing dose rates up to 6*10 12 rads(Si)/sec is presented. Existing theoretical predictions of the transient response of diffused resistors are summarized and compared to the experimentally measured values. The test resistors used allow the effects of sheet resistance and geometry on the transient response to be determined. The experimental results show that typical dielectrically isolated diffused resistors maintain adequate current limiting capability for use in radiation hardened integrated circuits

Improving the validity of quantitative measures in applied linguistics research

NARCIS (Netherlands)

Purpura, J.E.; Brown, J.D.; Schoonen, R.

2015-01-01

In empirical applied linguistics research it is essential that the key variables are operationalized in a valid and reliable way, and that the scores are treated appropriately, allowing for a proper testing of the hypotheses under investigation. The current article addresses several theoretical and

Critical current characteristics in high T/sub c/ oxide superconductors

International Nuclear Information System (INIS)

Matsushita, T.; Ni, B.

1989-01-01

Critical current densities are theoretically estimated for single-crystalline thin films, polycrystalline bulk materials with oriented and random textures of superconducting oxides. The percolation theory is used and the effect of depression of the transport current through grain boundaries is taken into account. A comparison is made with existing experimental results

Gender Relations and Economic Development: Hypotheses about the Reversal of Fortune in EurAsia

NARCIS (Netherlands)

de Pleijt, A.M.; van Zanden, J.L.; Carmichael, S.G.

2016-01-01

This paper develops an interrelated set of hypotheses about the links between gender relations, family systems and economic development in EurAsia. Firstly, we briefly discuss a number of ideas from the recent literature about the links between gender relations and economic development. Secondly, we

Application of radiofrequency superconductivity to accelerators for high-current ion beams

International Nuclear Information System (INIS)

Delayen, J.R.; Bohn, C.L.; Kennedy, W.L.; Roche, C.T.; Sagalovsky, L.

1992-01-01

A development program is underway to apply rf superconductivity to the design of continuous-wave (cw) linear accelerators for high-current, high-brightness ion beam. During the last few years, considerable progress has been made both experimentally and theoretically toward this application. Recent tests of niobium resonators for ion acceleration have yielded average accelerating gradients as high as 18 MV/m. In an experiment with a radio-frequency quadrupole geometry, niobium was found to sustain cw peak surface electric fields as high as 128 MV/m over large (10 cm) surface areas. Theoretical studies of beam halo, cumulative beam breakup and alternating-phase focusing have also yielded important results. This paper su-summarizes the recent progress and identifies current and future work in the areas of superconducting accelerator technology for high-current ion beams

Polarized parton distributions from charged-current deep-inelastic scattering and future neutrino factories

CERN Document Server

Forte, Stefano; Ridolfi, G; Forte, Stefano; Mangano, Michelangelo L.; Ridolfi, Giovanni

2001-01-01

We discuss the determination of polarized parton distributions from charged-current deep-inelastic scattering experiments. We summarize the next-to-leading order treatment of charged-current polarized structure functions, their relation to polarized parton distributions and scale dependence, and discuss their description by means of a next-to-leading order evolution code. We discuss current theoretical expectations and positivity constraints on the unmeasured C-odd combinations Delta q-Delta qbar of polarized quark distributions, and their determination in charged-current deep-inelastic scattering experiments. We give estimates of the expected errors on charged-current structure functions at a future neutrino factory, and perform a study of the accuracy in the determination of polarized parton distributions that would be possible at such a facility. We show that these measurements have the potential to distinguish between different theoretical scenarios for the proton spin structure.

Polarized parton distributions from charged-current deep-inelastic scattering and future neutrino factories

International Nuclear Information System (INIS)

Forte, Stefano; Mangano, Michelangelo L.; Ridolfi, Giovanni

2001-01-01

We discuss the determination of polarized parton distributions from charged-current deep-inelastic scattering experiments. We summarize the next-to-leading-order treatment of charged-current polarized structure functions, their relation to polarized parton distributions and scale dependence, and discuss their description by means of a next-to-leading-order evolution code. We discuss current theoretical expectations and positivity constraints on the unmeasured C-odd combinations Δq-Δq-bar of polarized quark distributions, and their determination in charged-current deep-inelastic scattering experiments. We give estimates of the expected errors on charged-current structure functions at a future neutrino factory, and perform a study of the accuracy in the determination of polarized parton distributions that would be possible at such a facility. We show that these measurements have the potential to distinguish between different theoretical scenarios for the proton spin structure

A New Theoretical Approach to Postsecondary Student Disability: Disability-Diversity (Dis)Connect Model

Science.gov (United States)

Aquino, Katherine C.

2016-01-01

Disability is often viewed as an obstacle to postsecondary inclusion, but not a characteristic of student diversity. Additionally, current theoretical frameworks isolate disability from other student diversity characteristics. In response, a new conceptual framework, the Disability-Diversity (Dis)Connect Model (DDDM), was created to address…

Predictions of fast wave heating, current drive, and current drive antenna arrays for advanced tokamaks

International Nuclear Information System (INIS)

Batchelor, D.B.; Baity, F.W.; Carter, M.D.

1994-01-01

The objective of the advanced tokamak program is to optimize plasma performance leading to a compact tokamak reactor through active, steady state control of the current profile using non-inductive current drive and profile control. To achieve these objectives requires compatibility and flexibility in the use of available heating and current drive systems--ion cyclotron radio frequency (ICRF), neutral beams, and lower hybrid. For any advanced tokamak, the following are important challenges to effective use of fast waves in various roles of direct electron heating, minority ion heating, and current drive: (1) to employ the heating and current drive systems to give self-consistent pressure and current profiles leading to the desired advanced tokamak operating modes; (2) to minimize absorption of the fast waves by parasitic resonances, which limit current drive; (3) to optimize and control the spectrum of fast waves launched by the antenna array for the required mix of simultaneous heating and current drive. The authors have addressed these issues using theoretical and computational tools developed at a number of institutions by benchmarking the computations against available experimental data and applying them to the specific case of TPX

Remote field eddy current testing

International Nuclear Information System (INIS)

Cheong, Y. M.; Jung, H. K.; Huh, H.; Lee, Y. S.; Shim, C. M.

2001-03-01

The state-of-art technology of the remote field eddy current, which is actively developed as an electromagnetic non-destructive testing tool for ferromagnetic tubes, is described. The historical background and recent R and D activities of remote-field eddy current technology are explained including the theoretical development of remote field eddy current, such as analytical and numerical approach, and the results of finite element analysis. The influencing factors for actual applications, such as the effect of frequency, magnetic permeability, receiving sensitivity, and difficulties of detection and classification of defects are also described. Finally, two examples of actual application, 1) the gap measurement between pressure tubes and calandria tube in CANDU reactor and, 2) the detection of defects in the ferromagnetic heat exchanger tubes, are described. The future research efforts are also included

Eddy current inspection of tubing

International Nuclear Information System (INIS)

Bauza, J. L. R.; Herrero, J.; Diaz, J.

1966-01-01

The Experimental research work carried out to develop a Eddy current testing equipment is described. Search coils with ferrite or air cores were used and the obtained results are discussed. Valuable information was gained from a improved channel in which a direct measure of the defect and the reference signal phase difference is obtained. Artificial defect used to evaluate resolution and sensitivity were produced by electro-machining and mechanical means. Finned SAP tubing was tested in a routine basis with the described equipment and the results plotted. Basic and theoretical considerations on the Eddy current testing technique are given in the last section of this report. (Author)

Testing Alternative Hypotheses Regarding the Association between Behavioral Inhibition and Language Development in Toddlerhood

Science.gov (United States)

Watts, Ashley K. Smith; Patel, Deepika; Corley, Robin P.; Friedman, Naomi P.; Hewitt, John K.; Robinson, JoAnn L.; Rhee, Soo H.

2014-01-01

Studies have reported an inverse association between language development and behavioral inhibition or shyness across childhood, but the direction of this association remains unclear. This study tested alternative hypotheses regarding this association in a large sample of toddlers. Data on behavioral inhibition and expressive and receptive…

Theoretical aspects of marketing management of consumer behavior

Directory of Open Access Journals (Sweden)

Danilenko Evgen

2015-11-01

Full Text Available The essence of consumer behavior finds expression in the actions of people under the influence of environmental factors and internal psychological or physical needs that arise in the process of life and socialization and are accompanied by information search, selection, acquisition, use of goods or services and getting rid of them. The article presents a synthesis of current theoretical terminology provisions on identification and definition of the nature of consumer behavior, allowing to improve conceptual and categorical apparatus by determining definitions of "marketing management", "consumer behavior".

Testing Hypotheses on Risk Factors for Scientific Misconduct via Matched-Control Analysis of Papers Containing Problematic Image Duplications.

Science.gov (United States)

Fanelli, Daniele; Costas, Rodrigo; Fang, Ferric C; Casadevall, Arturo; Bik, Elisabeth M

2018-02-19

It is commonly hypothesized that scientists are more likely to engage in data falsification and fabrication when they are subject to pressures to publish, when they are not restrained by forms of social control, when they work in countries lacking policies to tackle scientific misconduct, and when they are male. Evidence to test these hypotheses, however, is inconclusive due to the difficulties of obtaining unbiased data. Here we report a pre-registered test of these four hypotheses, conducted on papers that were identified in a previous study as containing problematic image duplications through a systematic screening of the journal PLoS ONE. Image duplications were classified into three categories based on their complexity, with category 1 being most likely to reflect unintentional error and category 3 being most likely to reflect intentional fabrication. We tested multiple parameters connected to the hypotheses above with a matched-control paradigm, by collecting two controls for each paper containing duplications. Category 1 duplications were mostly not associated with any of the parameters tested, as was predicted based on the assumption that these duplications were mostly not due to misconduct. Categories 2 and 3, however, exhibited numerous statistically significant associations. Results of univariable and multivariable analyses support the hypotheses that academic culture, peer control, cash-based publication incentives and national misconduct policies might affect scientific integrity. No clear support was found for the "pressures to publish" hypothesis. Female authors were found to be equally likely to publish duplicated images compared to males. Country-level parameters generally exhibited stronger effects than individual-level parameters, because developing countries were significantly more likely to produce problematic image duplications. This suggests that promoting good research practices in all countries should be a priority for the international

Elementary particle physics and cosmology: current status and prospects

International Nuclear Information System (INIS)

Rubakov, Valerii A

1999-01-01

The current status of elementary particle physics can be briefly summarized as follows: the Standard Model of elementary particles is perfectly (at the level of radiation effects!) adequate in describing all the available experimental data except for the recent indications of neutrino oscillations. At the same time, much (and possibly most) of today's cosmology is not encompassed by the Standard Model - a fact which, together with intrinsic theoretical difficulties and the neutrino oscillation challenge, strongly indicates that the Standard Model is incomplete. It is expected that in the current decade a 'new physics', i.e. particles and interactions beyond the Standard Model, will emerge. Major advances in cosmology, both in terms of qualitatively improved observations and theoretical analysis of the structure and evolution of the Universe, are expected as well. (special issue)

Dynamic response of HTS composite tapes to pulsed currents

International Nuclear Information System (INIS)

Meerovich, V; Sokolovsky, V; Prigozhin, L; Rozman, D

2006-01-01

Dynamic voltage-current characteristics of an HTS Ag/BiSCCO composite tape are studied both experimentally and theoretically. The tape is subjected to pulsed currents with different shapes and magnitudes and voltage traces are measured using the four-point method with different locations of potential taps on the sample surface. Clockwise and anticlockwise hysteresis loops are obtained for the same sample depending on the location of the potential taps. The dynamic characteristics deviate substantially from the DC characteristic, especially in the range of low voltages where a criterion for the critical current value is usually chosen (1-10 μV cm -1 ). The critical current determined from dynamic characteristics and its change with the pulse magnitude depend on the location of the potential taps and on the curve branch chosen for the critical current determination (ascending or descending). The theoretical analysis is based on a model of the magnetic flux diffusion into a composite tape for a superconductor described by the flux creep characteristic. Numerical simulation based on this model gives results in good agreement with the experimental ones and explains the observed peculiarities of the dynamic characteristics of HTS composite tapes. The difference between the magnetic diffusion into a tape and a slab is discussed

WRITTEN COLLABORATION/COOPERATION VIA INTERNET: THEORETICAL-PRACTICAL ISSUES TO INNOVATE WRITING PRACTICES AT SCHOOL

Directory of Open Access Journals (Sweden)

Petrilson Alan Pinheiro

2013-12-01

Full Text Available The objective of this paper is to carry out a theoretical discussion about collaborative text production (including the concepts of collaboration and coordination in the current socio-historical context. Such theoretical discussion is also based upon analyses of empirical data generated with a group of students of a public High School in the text production for a digital school newspaper, whose intention is to show how writing practices are constituted along a collaborative writing practices process and to present a conceptualization proposal of what I am calling ‘collaborative writing practices’

Landscape moderation of biodiversity patterns and processes - eight hypotheses.

Science.gov (United States)

Tscharntke, Teja; Tylianakis, Jason M; Rand, Tatyana A; Didham, Raphael K; Fahrig, Lenore; Batáry, Péter; Bengtsson, Janne; Clough, Yann; Crist, Thomas O; Dormann, Carsten F; Ewers, Robert M; Fründ, Jochen; Holt, Robert D; Holzschuh, Andrea; Klein, Alexandra M; Kleijn, David; Kremen, Claire; Landis, Doug A; Laurance, William; Lindenmayer, David; Scherber, Christoph; Sodhi, Navjot; Steffan-Dewenter, Ingolf; Thies, Carsten; van der Putten, Wim H; Westphal, Catrin

2012-08-01

Understanding how landscape characteristics affect biodiversity patterns and ecological processes at local and landscape scales is critical for mitigating effects of global environmental change. In this review, we use knowledge gained from human-modified landscapes to suggest eight hypotheses, which we hope will encourage more systematic research on the role of landscape composition and configuration in determining the structure of ecological communities, ecosystem functioning and services. We organize the eight hypotheses under four overarching themes. Section A: 'landscape moderation of biodiversity patterns' includes (1) the landscape species pool hypothesis-the size of the landscape-wide species pool moderates local (alpha) biodiversity, and (2) the dominance of beta diversity hypothesis-landscape-moderated dissimilarity of local communities determines landscape-wide biodiversity and overrides negative local effects of habitat fragmentation on biodiversity. Section B: 'landscape moderation of population dynamics' includes (3) the cross-habitat spillover hypothesis-landscape-moderated spillover of energy, resources and organisms across habitats, including between managed and natural ecosystems, influences landscape-wide community structure and associated processes and (4) the landscape-moderated concentration and dilution hypothesis-spatial and temporal changes in landscape composition can cause transient concentration or dilution of populations with functional consequences. Section C: 'landscape moderation of functional trait selection' includes (5) the landscape-moderated functional trait selection hypothesis-landscape moderation of species trait selection shapes the functional role and trajectory of community assembly, and (6) the landscape-moderated insurance hypothesis-landscape complexity provides spatial and temporal insurance, i.e. high resilience and stability of ecological processes in changing environments. Section D: 'landscape constraints on

Theoretical study on dynamical planar-chirality switching in checkerboard-like metasurfaces

Directory of Open Access Journals (Sweden)

Urade Yoshiro

2017-01-01

Full Text Available In this paper, we show that the handedness of a planar chiral checkerboard-like metasurface can be dynamically switched by modulating the local sheet impedance of the metasurface structure. We propose a metasurface design to realize the handedness switching and theoretically analyze its electromagnetic characteristic based on Babinet’s principle. Numerical simulations of the proposed metasurface are performed to validate the theoretical analysis. It is demonstrated that the polarity of asymmetric transmission for circularly polarized waves, which is determined by the planar chirality of the metasurface, is inverted by switching the sheet impedance at the interconnection points of the checkerboard-like structure. The physical origin of the asymmetric transmission is also discussed in terms of the surface current and charge distributions on the metasurface.

Method of Check of Statistical Hypotheses for Revealing of “Fraud” Point of Sale

Directory of Open Access Journals (Sweden)

T. M. Bolotskaya

2011-06-01

Full Text Available Application method checking of statistical hypotheses fraud Point of Sale working with purchasing cards and suspected of accomplishment of unauthorized operations is analyzed. On the basis of the received results the algorithm is developed, allowing receive an assessment of works of terminals in regime off-line.

Understanding Developmental Reversals in False Memory: Reply to Ghetti (2008) and Howe (2008)

Science.gov (United States)

Brainerd, C. J.; Reyna, V. F.; Ceci, S. J.; Holliday, R. E.

2008-01-01

S. Ghetti (2008) and M. L. Howe (2008) presented probative ideas for future research that will deepen scientific understanding of developmental reversals on false memory and establish boundary conditions for these counterintuitive patterns. Ghetti extended the purview of current theoretical principles by formulating hypotheses about how…

Children of Trauma: Stressful Life Events and Their Effects on Children and Adolescents. International Universities Press Stress and Health Series. Monograph 8.

Science.gov (United States)

Miller, Thomas W., Ed.

Clinical theory and practice models are provided along with current concepts in diagnosis and treatment. Theoretical formulations, hypotheses, issues, and implications related to life stress measurement are addressed and applied to medical and mental health concerns. Contributions include: (1) "Stress Response and Adaptation in Children:…

Quantifying heterogeneity attributable to polythetic diagnostic criteria: theoretical framework and empirical application.

Science.gov (United States)

Olbert, Charles M; Gala, Gary J; Tupler, Larry A

2014-05-01

Heterogeneity within psychiatric disorders is both theoretically and practically problematic: For many disorders, it is possible for 2 individuals to share very few or even no symptoms in common yet share the same diagnosis. Polythetic diagnostic criteria have long been recognized to contribute to this heterogeneity, yet no unified theoretical understanding of the coherence of symptom criteria sets currently exists. A general framework for analyzing the logical and mathematical structure, coherence, and diversity of Diagnostic and Statistical Manual diagnostic categories (DSM-5 and DSM-IV-TR) is proposed, drawing from combinatorial mathematics, set theory, and information theory. Theoretical application of this framework to 18 diagnostic categories indicates that in most categories, 2 individuals with the same diagnosis may share no symptoms in common, and that any 2 theoretically possible symptom combinations will share on average less than half their symptoms. Application of this framework to 2 large empirical datasets indicates that patients who meet symptom criteria for major depressive disorder and posttraumatic stress disorder tend to share approximately three-fifths of symptoms in common. For both disorders in each of the datasets, pairs of individuals who shared no common symptoms were observed. Any 2 individuals with either diagnosis were unlikely to exhibit identical symptomatology. The theoretical and empirical results stemming from this approach have substantive implications for etiological research into, and measurement of, psychiatric disorders.

Eddy-current effect on resonant magnetoelectric coupling in magnetostrictive-piezoelectric laminated composites

Science.gov (United States)

Liu, Guoxi; Zhang, Chunli; Chen, Weiqiu; Dong, Shuxiang

2013-07-01

An analytical model of resonant magnetoelectric (ME) coupling in magnetostrictive (MS)-piezoelectric (PE) laminated composites in consideration of eddy-current effect in MS layer using equivalent circuit method is presented. Numerical calculations show that: (1) the eddy-current has a strong effect on ME coupling in MS-PE laminated composites at resonant frequency; and (2) the resonant ME coupling is then significantly dependent on the sizes of ME laminated composites, which were neglected in most previous theoretical analyses. The achieved results provide a theoretical guidance for the practice engineering design, manufacture, and application of ME laminated composites and devices.

AN INVESTIGATION OF THE HYPOTHESES FOR FORMATION OF THE PLATY-RIDGED-POLYGONIZED TERRAIN IN ELYSIUM PLANITIA, MARS

Directory of Open Access Journals (Sweden)

Z. Yue

2017-07-01

Full Text Available The origin of the platy-ridged-polygonized (PRP terrains on Martian surface has long been debated. The terrain has generally been classified as water, pack ice, or basalt lava related flow. The crater counting results of the PRP terrains suggest they are geologically very young; therefore, they are significant in understanding the recent evolution of Mars. This work evaluated the current hypotheses through detailed analysis of the distribution and microtopographies with the High Resolution Imaging Science Experiment (HiRISE images for the PRP terrains in Elysium Planitia, Mars. Quantitative measurements and statistics of the typical features of the PRP terrains were also made. In addition, we also found an analog site in Tarim Basin in Xinjiang, China. Our results suggest that mud flow is responsible for the formation of the PRP terrains on the Mars surface, although the hypothesis of low-viscosity basalt lava floods cannot be completely excluded. This finding implies that a regional environment suitable for liquid water may have existed in recent geologic time, which has great importance for future Mars scientific exploration.

Hypotheses regarding the mechanisms of ayahuasca in the treatment of addictions.

Science.gov (United States)

Liester, Mitchell B; Prickett, James I

2012-01-01

Ayahuasca is a medicinal plant mixture utilized by indigenous peoples throughout the Amazon River basin for healing purposes. The "vine of the soul" or "vine of death," as it is known in South America, contains a combination of monoamine oxidase inhibitors and N,N-dimethyltryptamine (DMT). When ingested together, these medicines produce profound alterations in consciousness. Increasingly, ayahuasca is being utilized to treat addictions. However, the mechanism of action by which ayahuasca treats addictions remains unclear. We offer four hypotheses to explain possible biochemical, physiological, psychological, and transcendent mechanisms by which ayahuasca may exert its anti-addiction effects.

The critical current of superconductors: an historical review

International Nuclear Information System (INIS)

Dew-Hughes, D.

2001-01-01

The most important practical characteristic of a superconductor is its critical current density. This article traces the history, both of the experimental discoveries and of the development of the theoretical ideas that have lead to the understanding of those factors that control critical current densities. These include Silsbee's hypothesis, the Meissner effect, London, Ginsburg-Landau and Abrikosov theories, flux pinning and the critical state, and the control of texture in high temperature superconductors

Facial emotion recognition in Parkinson's disease: A review and new hypotheses

Science.gov (United States)

Vérin, Marc; Sauleau, Paul; Grandjean, Didier

2018-01-01

Abstract Parkinson's disease is a neurodegenerative disorder classically characterized by motor symptoms. Among them, hypomimia affects facial expressiveness and social communication and has a highly negative impact on patients' and relatives' quality of life. Patients also frequently experience nonmotor symptoms, including emotional‐processing impairments, leading to difficulty in recognizing emotions from faces. Aside from its theoretical importance, understanding the disruption of facial emotion recognition in PD is crucial for improving quality of life for both patients and caregivers, as this impairment is associated with heightened interpersonal difficulties. However, studies assessing abilities in recognizing facial emotions in PD still report contradictory outcomes. The origins of this inconsistency are unclear, and several questions (regarding the role of dopamine replacement therapy or the possible consequences of hypomimia) remain unanswered. We therefore undertook a fresh review of relevant articles focusing on facial emotion recognition in PD to deepen current understanding of this nonmotor feature, exploring multiple significant potential confounding factors, both clinical and methodological, and discussing probable pathophysiological mechanisms. This led us to examine recent proposals about the role of basal ganglia‐based circuits in emotion and to consider the involvement of facial mimicry in this deficit from the perspective of embodied simulation theory. We believe our findings will inform clinical practice and increase fundamental knowledge, particularly in relation to potential embodied emotion impairment in PD. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society. PMID:29473661

Current Status of Experimental and Theoretical Work on Sodium/Fuel Interaction (SFI) at Karlsruhe 'Code Developments'

International Nuclear Information System (INIS)

Beutel, H.; Bojarsky, E.; Reiser, H.; Caldarola, L.; Jacobs, H.; Zyszkowski, W.

1976-01-01

The theoretical work follows two main lines: A. Code development; B. Theoretical work on fragmentation. Two computer codes have been developed. The first code contains a heat transfer model (during the vaporization phase) based on the inverse Leidenfrost phenomenon (which has been observed experimentally in water). The exact solution of the heat diffusion equation in a sphere is included in the code. The code accounts for the time history of each fuel particle by means of specially averaged temperature values. The presence of fission gases can also be taken into account. A size distribution of fuel particles has also been incorporated in the code as well as the effect of the friction due to the channel walls and that of the pressure losses at channel outlet. An extensive parametric study has been carried out with this code. The main conclusions are the following: 1. Total mechanical work strongly decreases with the fragmentation and/or mixing time constants. 2. Vapour blanketing during the vaporization phase is effective only if accompanied by a relatively slow process of fragmentation and mixing. In this case total mechanical work strongly decreased with degree of vapour blanketing. 3. Total mechanical work rises with initial length of sodium piston. 4. Time to empty the 120 cm long channel is 15-20 msecs. for values of the fragmentation and/or mixing time constants of the order of 5-10 msecs. 5. Effects due to particle size distribution and gas content are important only fora rapid fragmentation and mixing process. It must be painted out that (as far as the gas is concerned) this conclusion is valid only within the limits of the effects (due to the gas) which have been considered in the model. Propagation effects can be analysed by using the second code. The interaction region can be subdivided into an arbitrary number of sections, each containing fuel and coolant. The thermal conductivity of the liquid sodium has also been taken into account, as well as the

Ultra-low current biosensor output detection using portable electronic reader

Science.gov (United States)

Yahaya, N. A. N.; Rajapaksha, R. D. A. A.; Uda, M. N. Afnan; Hashim, U.

2017-09-01

Generally, the electrical biosensor usually shows extremely low current signal output around pico ampere to microampere range. In this research, electronic reader with amplifier has been demonstrated to detect ultra low current via the biosensor. The operational amplifier Burr-Brown OPA 128 and Arduino Uno board were used to construct the portable electronic reader. There are two cascaded inverting amplifier were used to detect ultra low current through the biosensor from pico amperes (pA) to nano amperes ranges (nA). A small known input current was form by applying variable voltage between 0.1V to 5.0V across a 5GΩ high resistor to check the amplifier circuit. The amplifier operation was measured with the high impedance current source and has been compared with the theoretical measurement. The Arduino Uno was used to convert the analog signal to digital signal and process the data to display on reader screen. In this project, Proteus software was used to design and test the circuit. Then it was implemented together with Arduino Uno board. Arduino board was programmed using C programming language to make whole circuit communicate each order. The current was measured then it shows a small difference values compared to theoretical values, which is approximately 14pA.

A criterion for testing hypotheses about the covariance function of a stationary Gaussian stochastic process

OpenAIRE

Kozachenko, Yuriy; Troshki, Viktor

2015-01-01

We consider a measurable stationary Gaussian stochastic process. A criterion for testing hypotheses about the covariance function of such a process using estimates for its norm in the space $L_p(\\mathbb {T}),\\,p\\geq1$, is constructed.

CONSIDERATION REGARDING CURRENT ASSETS IN THE CONSTRUCTION ENTITIES

Directory of Open Access Journals (Sweden)

Laura Adriana COJOCARU (ALIONESCU

2014-06-01

Full Text Available Accounting for current assets mainly aims to obtain useful information on the management of their best in order to make management decisions. Counting efficiency of these assets, their importance, provides improved performance of the entity. In this paper we want to study the degree of implementation of policies and accounting treatments on the current assets in the specific construction economic entities, the problems of implementation and thus better addressing their theoretical and procedural to improve the information provided by financial statements. Due to the importance of proper conduct of business owned entities, accounting current assets should result in optimal and efficient control of current assets.

Learned Helplessness and Depression in a Clinical Population: A Test of Two Behavioral Hypotheses

Science.gov (United States)

And Others; Price, Kenneth P.

1978-01-01

This study was undertaken to extend the learned helplessness phenomenon to a clinical population and to test the competing hypotheses of Seligman and Lewinsohn. 96 male hospitalized psychiatric and medical patients were randomly assigned to one of four experimental conditions. Results replicate the learned helplessness phenomenon in a group of…

Skin Stem Cell Hypotheses and Long Term Clone Survival – Explored Using Agent-based Modelling

Science.gov (United States)

Li, X.; Upadhyay, A. K.; Bullock, A. J.; Dicolandrea, T.; Xu, J.; Binder, R. L.; Robinson, M. K.; Finlay, D. R.; Mills, K. J.; Bascom, C. C.; Kelling, C. K.; Isfort, R. J.; Haycock, J. W.; MacNeil, S.; Smallwood, R. H.

2013-01-01

Epithelial renewal in skin is achieved by the constant turnover and differentiation of keratinocytes. Three popular hypotheses have been proposed to explain basal keratinocyte regeneration and epidermal homeostasis: 1) asymmetric division (stem-transit amplifying cell); 2) populational asymmetry (progenitor cell with stochastic fate); and 3) populational asymmetry with stem cells. In this study, we investigated lineage dynamics using these hypotheses with a 3D agent-based model of the epidermis. The model simulated the growth and maintenance of the epidermis over three years. The offspring of each proliferative cell was traced. While all lineages were preserved in asymmetric division, the vast majority were lost when assuming populational asymmetry. The third hypothesis provided the most reliable mechanism for self-renewal by preserving genetic heterogeneity in quiescent stem cells, and also inherent mechanisms for skin ageing and the accumulation of genetic mutation. PMID:23712735

A survey of theoretical research on the EXTRAP concept

International Nuclear Information System (INIS)

Lehnert, B.

1988-12-01

A review is given of the theoretical analysis on the Extrap concept which consists of a Z-pinch being immersed in an octupole field generated by currents in a set of external conductors. This analysis includes research on plasma breakdown and start-up, equilibrium and stability, in terms of MHD and kinetic theory. Extrap theory includes an extensive area of diversified problems, being related to a high beta value, a non-circular plasma cross section with a magnetic separatrix, and strongly inhomogeneous plasma conditions in space. This also leads to unexplored and important areas of plasma physics, reaching far beyond the special applications to the Extrap configuration. At present progress has been made in the analysis of breakdown, of dissipation-free equilibria, and in identifying the instability modes and possible stabilizing meachanisms in Extrap. Nevertheless much work still remains within the area of dissipative equilibria and transport, as well as in the efforts to reach a complete theoretical understanding of the experimentally observed stability. (115 refs.)

Tidal current energy resource assessment in Ireland: Current status and future update

International Nuclear Information System (INIS)

O'Rourke, Fergal; Boyle, Fergal; Reynolds, Anthony

2010-01-01

Interest in renewable energy in Ireland has increased continually over the past decade. This interest is due primarily to security of supply issues and the effects of climate change. Ireland imports over 90% of its primary energy consumption, mostly in the form of fossil fuels. The exploitation of Ireland's vast indigenous renewable energy resources is required in order to reduce this over-dependence on fossil fuel imports to meet energy demand. Various targets have been set by the Irish government to incorporate renewable energy technologies into Ireland's energy market. As a result of these targets, the development in wind energy has increased substantially over the past decade; however this method of energy extraction is intermittent and unpredictable. Ireland has an excellent tidal current energy resource and the use of this resource will assist in the development of a sustainable energy future. Energy extraction using tidal current energy technologies offers a vast and predictable energy resource. This paper reviews the currently accepted tidal current energy resource assessment for Ireland. This assessment was compiled by Sustainable Energy Ireland in a report in 2004. The assessment employed a 2-dimensional numerical model of the tidal current velocities around Ireland, and from this numerical model the theoretical tidal current energy resource was identified. With the introduction of constraints and limitations, the technical, practical, accessible and viable tidal current energy resources were obtained. The paper discusses why the assessment needs updating including the effect on the assessment of the current stage of development of tidal current turbines and their deployment technology. (author)

Continuous infusion thermodilution for assessment of coronary flow: Theoretical background and in vitro validation

NARCIS (Netherlands)

Veer, van 't M.; Geven, M.C.F.; Rutten, M.C.M.; Horst, van der A.; Aarnoudse, W.H.; Pijls, N.H.J.; Vosse, van de F.N.

2009-01-01

Direct volumetric assessment of coronary flow during cardiac catheterization has not been available so far. In the current study continuous infusion thermodilution, a method based on continuous infusion of saline into a selective coronary artery is evaluated. Theoretically, volumetric flow can be

Testing contingency hypotheses in budgetary research: An evaluation of the use of moderated regression analysis

NARCIS (Netherlands)

Hartmann, Frank G.H.; Moers, Frank

1999-01-01

In the contingency literature on the behavioral and organizational effects of budgeting, use of the Moderated Regression Analysis (MRA) technique is prevalent. This technique is used to test contingency hypotheses that predict interaction effects between budgetary and contextual variables. This

Predictions of of fast wave heating, current drive, and current drive antenna arrays for advanced tokamaks

International Nuclear Information System (INIS)

Batchelor, D.B.; Baity, F.W.; Carter, M.D.

1995-01-01

The objective of the advanced tokamak program is to optimize plasma performance leading to a compact tokamak reactor through active, steady state control of the current profile using non-inductive current drive and profile control. To achieve this objective requires compatibility and flexibility in the use of available heating and current drive systems - ion cyclotron radio frequency (ICRF), neutral beams, and lower hybrid. For any advanced tokamak, the following are important challenges to effective use of fast waves in various role of direct electron heating, minority ion heating, and current drive: (1) to employ the heating and current drive systems to give self-consistent pressure and current profiles leading to the desired advanced tokamak operating modes; (2) to minimize absorption of the fast waves by parasitic resonances, which limit current drive; (3) to optimize and control the spectrum of fast waves launched by the antenna array for the required mix of simultaneous heating and current drive. The paper addresses these issues using theoretical and computational tools developed at a number of institutions by benchmarking the computations against available experimental data and applying them to the specific case of TPX. (author). 6 refs, 3 figs

Resistance and Renewal in Theoretical Psychology

DEFF Research Database (Denmark)

psychology, resistance and renewal, form the overall theme for a selection of theoretical papers that is framed — in this iteration of the International Society for Theoretical Psychology's (ISTP) proceedings — by reflections on the 30 year history of the ISTP as well as by considerations of the future....... The diversity and creativity of the work undertaken within theoretical psychology is further exemplified by papers on the history of the ISTP and theoretical psychology, a new paradigm for functional disorders, experimental introspection and techniques of self, the performativity of psychological science......Theoretical psychologists continue to challenge psychology, related disciplines and the work of other theoretical psychologists through a wide variety of activities that include conceptual clarification and creative theorizing. In many cases, these activities are experienced by the relevant...

The WIMP Paradigm: Current Status

International Nuclear Information System (INIS)

Feng, Jonathan

2011-01-01

The WIMP paradigm is the glue that joins together much of the high energy and cosmic frontiers. It postulates that most of the matter in the Universe is made of weakly-interacting massive particles, with implications for a broad range of experiments and observations. I will review the WIMP paradigm's underlying motivations, its current status in view of rapid experimental progress on several fronts, and recent theoretical variations on the WIMP paradigm theme.

Theoretic base of Edge Local Mode triggering by vertical displacements

Energy Technology Data Exchange (ETDEWEB)

Wang, Z. T. [Southwestern Institute of Physics, Chengdu 610041 (China); College of Physics Science and Technology, Sichuan University, Chengdu 610065 (China); He, Z. X.; Wang, Z. H. [Southwestern Institute of Physics, Chengdu 610041 (China); Wu, N.; Tang, C. J. [College of Physics Science and Technology, Sichuan University, Chengdu 610065 (China)

2015-05-15

Vertical instability is studied with R-dependent displacement. For Solovev's configuration, the stability boundary of the vertical instability is calculated. The pressure gradient is a destabilizing factor which is contrary to Rebhan's result. Equilibrium parallel current density, j{sub //}, at plasma boundary is a drive of the vertical instability similar to Peeling-ballooning modes; however, the vertical instability cannot be stabilized by the magnetic shear which tends towards infinity near the separatrix. The induced current observed in the Edge Local Mode (ELM) triggering experiment by vertical modulation is derived. The theory provides some theoretic explanation for the mitigation of type-I ELMS on ASDEX Upgrade. The principle could be also used for ITER.

Optimized calculation of the synergy conditions between electron cyclotron current drive and lower hybrid current drive on EAST

International Nuclear Information System (INIS)

Wei Wei; Ding Bo-Jiang; Li Miao-Hui; Zhang Xin-Jun; Wang Xiao-Jie; Peysson, Y; Decker, J; Zhang Lei

2016-01-01

The optimized synergy conditions between electron cyclotron current drive (ECCD) and lower hybrid current drive (LHCD) with normal parameters of the EAST tokamak are studied by using the C3PO/LUKE code based on the understanding of the synergy mechanisms so as to obtain a higher synergistic current and provide theoretical reference for the synergistic effect in the EAST experiment. The dependences of the synergistic effect on the parameters of two waves (lower hybrid wave (LHW) and electron cyclotron wave (ECW)), including the radial position of the power deposition, the power value of the LH and EC waves, and the parallel refractive indices of the LHW (N ∥ ) are presented and discussed. (paper)

Ion current prediction model considering columnar recombination in alpha radioactivity measurement using ionized air transportation

International Nuclear Information System (INIS)

Naito, Susumu; Hirata, Yosuke; Izumi, Mikio; Sano, Akira; Miyamoto, Yasuaki; Aoyama, Yoshio; Yamaguchi, Hiromi

2007-01-01

We present a reinforced ion current prediction model in alpha radioactivity measurement using ionized air transportation. Although our previous model explained the qualitative trend of the measured ion current values, the absolute values of the theoretical curves were about two times as large as the measured values. In order to accurately predict the measured values, we reinforced our model by considering columnar recombination and turbulent diffusion, which affects columnar recombination. Our new model explained the considerable ion loss in the early stage of ion diffusion and narrowed the gap between the theoretical and measured values. The model also predicted suppression of ion loss due to columnar recombination by spraying a high-speed air flow near a contaminated surface. This suppression was experimentally investigated and confirmed. In conclusion, we quantitatively clarified the theoretical relation between alpha radioactivity and ion current in laminar flow and turbulent pipe flow. (author)

Remote field eddy current testing of ferromagnetic tubes

International Nuclear Information System (INIS)

David, B.

1990-01-01

In order to test ferromagnetic tubes using internal probes, Intercontrole and the CEA have carried out theoretical and experimental works and developed a method to adapt the Remote Field Eddy Current technique which has been known and used for 30 years now. This document briefly recalls the basic principles of the Remote Field Eddy Current technique, the various steps of the works carried out and mainly describes examples of field inspection of ferromagnetic tubes and pipes [fr

General Potential-Current Model and Validation for Electrocoagulation

International Nuclear Information System (INIS)

Dubrawski, Kristian L.; Du, Codey; Mohseni, Madjid

2014-01-01

A model relating potential and current in continuous parallel plate iron electrocoagulation (EC) was developed for application in drinking water treatment. The general model can be applied to any EC parallel plate system relying only on geometric and tabulated input variables without the need of system-specific experimentally derived constants. For the theoretical model, the anode and cathode were vertically divided into n equipotential segments in a single pass, upflow, and adiabatic EC reactor. Potential and energy balances were simultaneously solved at each vertical segment, which included the contribution of ionic concentrations, solution temperature and conductivity, cathodic hydrogen flux, and gas/liquid ratio. We experimentally validated the numerical model with a vertical upflow EC reactor using a 24 cm height 99.99% pure iron anode divided into twelve 2 cm segments. Individual experimental currents from each segment were summed to determine total current, and compared with the theoretically derived value. Several key variables were studied to determine their impact on model accuracy: solute type, solute concentration, current density, flow rate, inter-electrode gap, and electrode surface condition. Model results were in good agreement with experimental values at cell potentials of 2-20 V (corresponding to a current density range of approximately 50-800 A/m 2 ), with mean relative deviation of 9% for low flow rate, narrow electrode gap, polished electrodes, and 150 mg/L NaCl. Highest deviation occurred with a large electrode gap, unpolished electrodes, and Na 2 SO 4 electrolyte, due to parasitic H 2 O oxidation and less than unity current efficiency. This is the first general model which can be applied to any parallel plate EC system for accurate electrochemical voltage or current prediction

Interactions between domestic and export markets for softwood lumber and plywood: tests of six hypotheses.

Science.gov (United States)

David R. Darr

1981-01-01

Price formation in export markets and available data on export and domestic markets are discussed. The results of tests of several hypotheses about interactions between domestic and export markets are presented and interpreted from the standpoints of trade promotion and trade policy.

Utility of Krashen's Five Hypotheses in the Saudi Context of Foreign Language Acquisition/Learning

Science.gov (United States)

Gulzar, Malik Ajmal; Gulnaz, Fahmeeda; Ijaz, Attiya

2014-01-01

In the last twenty years, the paradigm that has dominated the discipline of language teaching is the SLA theory and Krashen's five hypotheses which are still proving flexible to accommodate earlier reforms. This paper reviews second language acquisition (SLA) theory to establish an understanding of its role in the EFL/ESL classrooms. Other areas…

Testing the Efficacy of Theoretically Derived Improvements in the Treatment of Social Phobia

Science.gov (United States)

Rapee, Ronald M.; Gaston, Jonathan E.; Abbott, Maree J.

2009-01-01

Recent theoretical models of social phobia suggest that targeting several specific cognitive factors in treatment should enhance treatment efficacy over that of more traditional skills-based treatment programs. In the current study, 195 people with social phobia were randomly allocated to 1 of 3 treatments: standard cognitive restructuring plus in…

Structural Learning Theory: Current Status and New Perspectives.

Science.gov (United States)

Scandura, Joseph M.

2001-01-01

Presents the current status and new perspectives on the Structured Learning Theory (SLT), with special consideration given to how SLT has been influenced by recent research in software engineering. Topics include theoretical constructs; content domains; structural analysis; cognition; assessing behavior potential; and teaching and learning issues,…

Current Consumption Measurements with a Carrier Aggregation Smartphone

DEFF Research Database (Denmark)

Sanchez-Mejias, Rafael; Guo, Yu; Lauridsen, Mads

2014-01-01

on this topic. Currently there are only theoretical expansions of LTE release 8 power models available, but this article presents the first publicly available current consumption measurements on a commercial CA-capable UE. In this work it is examined how the activation and use of CA (10 + 10 MHz) affects the UE......Carrier Aggregation (CA) is introduced in LTE release 10 to improve data rates by allowing the User Equipment (UE) to receive data on more than one LTE carrier. The related increased complexity is expected to affect the UE current consumption, but yet no empirical evaluation has been published...

Theoretical aspects of an electrostatic aerosol filter for civilian turbofan engines

Directory of Open Access Journals (Sweden)

Valeriu DRAGAN

2012-03-01

Full Text Available The paper addresses the problem of aerosol filtration in turbofan engines. The current problem of very fine aerosol admission is the impossibility for mechanical filtration; another aspect of the problem is the high mass flow of air to be filtered. Non-attended, the aerosol admission can -and usually does- lead to clogging of turbine cooling passages and can damage the engine completely. The approach is theoretical and relies on the principles of electrostatic dust collectors known in other industries. An estimative equation is deduced in order to quantify the electrical charge required to obtain the desired filtration. Although the device still needs more theoretical and experimental work, it could one day be used as a means of increasing the safety of airplanes passing trough an aerosol laden mass of air.

Persistent currents in three-dimensional shell-doped nanorings

International Nuclear Information System (INIS)

Ning, Xu; Jian-Wen, Ding; Hong-Bo, Chen; Ming-Ming, Ma

2009-01-01

The persistent current in three-dimensional (P × N 2 ) nanorings as a function of the unit cell number (P), the channel number (M = N 2 ), surface disorder (ξ), and temperature (T) is theoretically investigated in terms of rotational symmetry. On the whole, the typical current increases linearly with √M but decreases exponentially with P, while wide fluctuations exist therein. In the presence of surface disorder, the persistent current decreases with ξ in the regime of weak disorder but increases in the regime of strong disorder. In addition, it is found that the persistent current in perfect rings decreases exponentially with temperature even at T * , while in most disorder rings, the typical current decreases slightly with temperature at T *

Nursing theory and the delivery of compassionate care.

Science.gov (United States)

Power, Louisa

2016-02-10

Compassionate care is a priority in current healthcare policy. However, its definition is amorphous, leading to difficulties standardising it in practice. This article discusses how nursing theory is central to the delivery of compassionate care. It emphasises the need to develop a theoretical framework that reflects the eclectic and pragmatic nature of nursing practice, and the importance of using patient feedback as an indicator of the quality of care and as a basis for adapting theoretical hypotheses.

Baring high-albedo soils by overgrazing - A hypothesized desertification mechanism

Science.gov (United States)

Otterman, J.

1974-01-01

Observations are reported of high-albedo soils denuded by overgrazing which appear bright, in high contrast to regions covered by natural vegetation. Measurements and modeling show that the denuded surfaces are cooler, when compared under sunlit conditions. This observed 'thermal depression' effect should, on theoretical grounds, result in a decreased lifting of air necessary for cloud formation and precipitation, and thus lead to regional climatic desertification.

Wireless Information-Theoretic Security in an Outdoor Topology with Obstacles: Theoretical Analysis and Experimental Measurements

Directory of Open Access Journals (Sweden)

Dagiuklas Tasos

2011-01-01

Full Text Available This paper presents a Wireless Information-Theoretic Security (WITS scheme, which has been recently introduced as a robust physical layer-based security solution, especially for infrastructureless networks. An autonomic network of moving users was implemented via 802.11n nodes of an ad hoc network for an outdoor topology with obstacles. Obstructed-Line-of-Sight (OLOS and Non-Line-of-Sight (NLOS propagation scenarios were examined. Low-speed user movement was considered, so that Doppler spread could be discarded. A transmitter and a legitimate receiver exchanged information in the presence of a moving eavesdropper. Average Signal-to-Noise Ratio (SNR values were acquired for both the main and the wiretap channel, and the Probability of Nonzero Secrecy Capacity was calculated based on theoretical formula. Experimental results validate theoretical findings stressing the importance of user location and mobility schemes on the robustness of Wireless Information-Theoretic Security and call for further theoretical analysis.

On the spreading and instability of gravity current fronts of arbitrary shape

Science.gov (United States)

Zgheib, N.; Bonometti, T.; Balachandar, S.

2012-11-01

Experiments, simulations and theoretical analysis were carried out to study the influence of geometry on the spreading of gravity currents. The horizontal spreading of three different intial planforms of initial release were investigated: an extended ellipse, a cross, and a circle. The experiments used a pulley system for a swift nearly instantaneous release. The case of the axisymmetric cylinder compared favorably with earlier simulations. We ran experiments for multiple aspect ratios for all three configurations. Perhaps the most intriguing of the three cases is the ``ellipse,'' which within a short period of release flipped the major and minor axes. This behavior cannot be captured by current theoretical methods (such as the Box Model). These cases have also been investigated using shallow water and direct numerical simulations. Also, in this study, we investigate the possibility of a Rayleigh-Taylor (RT) instability of the radially moving, but decelerating front. We present a simple theoretical framework based on the inviscid Shallow Water Equations. The theoretical results are supplemented and compared to highly resolved three-dimensional simulations with the Boussinesq approximation. Chateaubriand Fellowship - NSF PIRE grant OISE-0968313.

Pathways from Trauma to Psychotic Experiences: A Theoretically Informed Model of Posttraumatic Stress in Psychosis

Directory of Open Access Journals (Sweden)

Amy Hardy

2017-05-01

Full Text Available In recent years, empirical data and theoretical accounts relating to the relationship between childhood victimization and psychotic experiences have accumulated. Much of this work has focused on co-occurring Posttraumatic Stress Disorder or putative causal mechanisms in isolation from each other. The complexity of posttraumatic stress reactions experienced in psychosis remains poorly understood. This paper therefore attempts to synthesize the current evidence base into a theoretically informed, multifactorial model of posttraumatic stress in psychosis. Three trauma-related vulnerability factors are proposed to give rise to intrusions and to affect how people appraise and cope with them. First, understandable attempts to survive trauma become habitual ways of regulating emotion, manifesting in cognitive-affective, behavioral and interpersonal responses. Second, event memories, consisting of perceptual and episodic representations, are impacted by emotion experienced during trauma. Third, personal semantic memory, specifically appraisals of the self and others, are shaped by event memories. It is proposed these vulnerability factors have the potential to lead to two types of intrusions. The first type is anomalous experiences arising from emotion regulation and/or the generation of novel images derived from trauma memory. The second type is trauma memory intrusions reflecting, to varying degrees, the retrieval of perceptual, episodic and personal semantic representations. It is speculated trauma memory intrusions may be experienced on a continuum from contextualized to fragmented, depending on memory encoding and retrieval. Personal semantic memory will then impact on how intrusions are appraised, with habitual emotion regulation strategies influencing people’s coping responses to these. Three vignettes are outlined to illustrate how the model accounts for different pathways between victimization and psychosis, and implications for therapy are

Representing general theoretical concepts in structural equation models: The role of composite variables

Science.gov (United States)

Grace, J.B.; Bollen, K.A.

2008-01-01

Structural equation modeling (SEM) holds the promise of providing natural scientists the capacity to evaluate complex multivariate hypotheses about ecological systems. Building on its predecessors, path analysis and factor analysis, SEM allows for the incorporation of both observed and unobserved (latent) variables into theoretically-based probabilistic models. In this paper we discuss the interface between theory and data in SEM and the use of an additional variable type, the composite. In simple terms, composite variables specify the influences of collections of other variables and can be helpful in modeling heterogeneous concepts of the sort commonly of interest to ecologists. While long recognized as a potentially important element of SEM, composite variables have received very limited use, in part because of a lack of theoretical consideration, but also because of difficulties that arise in parameter estimation when using conventional solution procedures. In this paper we present a framework for discussing composites and demonstrate how the use of partially-reduced-form models can help to overcome some of the parameter estimation and evaluation problems associated with models containing composites. Diagnostic procedures for evaluating the most appropriate and effective use of composites are illustrated with an example from the ecological literature. It is argued that an ability to incorporate composite variables into structural equation models may be particularly valuable in the study of natural systems, where concepts are frequently multifaceted and the influence of suites of variables are often of interest. ?? Springer Science+Business Media, LLC 2007.

Theoretical methods and models for mechanical properties of soft biomaterials

Directory of Open Access Journals (Sweden)

Zhonggang Feng

2017-06-01

Full Text Available We review the most commonly used theoretical methods and models for the mechanical properties of soft biomaterials, which include phenomenological hyperelastic and viscoelastic models, structural biphasic and network models, and the structural alteration theory. We emphasize basic concepts and recent developments. In consideration of the current progress and needs of mechanobiology, we introduce methods and models for tackling micromechanical problems and their applications to cell biology. Finally, the challenges and perspectives in this field are discussed.

Theoretical computer science and the natural sciences

Science.gov (United States)

Marchal, Bruno

2005-12-01

I present some fundamental theorems in computer science and illustrate their relevance in Biology and Physics. I do not assume prerequisites in mathematics or computer science beyond the set N of natural numbers, functions from N to N, the use of some notational conveniences to describe functions, and at some point, a minimal amount of linear algebra and logic. I start with Cantor's transcendental proof by diagonalization of the non enumerability of the collection of functions from natural numbers to the natural numbers. I explain why this proof is not entirely convincing and show how, by restricting the notion of function in terms of discrete well defined processes, we are led to the non algorithmic enumerability of the computable functions, but also-through Church's thesis-to the algorithmic enumerability of partial computable functions. Such a notion of function constitutes, with respect to our purpose, a crucial generalization of that concept. This will make easy to justify deep and astonishing (counter-intuitive) incompleteness results about computers and similar machines. The modified Cantor diagonalization will provide a theory of concrete self-reference and I illustrate it by pointing toward an elementary theory of self-reproduction-in the Amoeba's way-and cellular self-regeneration-in the flatworm Planaria's way. To make it easier, I introduce a very simple and powerful formal system known as the Schoenfinkel-Curry combinators. I will use the combinators to illustrate in a more concrete way the notion introduced above. The combinators, thanks to their low-level fine grained design, will also make it possible to make a rough but hopefully illuminating description of the main lessons gained by the careful observation of nature, and to describe some new relations, which should exist between computer science, the science of life and the science of inert matter, once some philosophical, if not theological, hypotheses are made in the cognitive sciences. In the

Hash functions and information theoretic security

DEFF Research Database (Denmark)

Bagheri, Nasoor; Knudsen, Lars Ramkilde; Naderi, Majid

2009-01-01

Information theoretic security is an important security notion in cryptography as it provides a true lower bound for attack complexities. However, in practice attacks often have a higher cost than the information theoretic bound. In this paper we study the relationship between information theoretic...

Breaking the current density threshold in spin-orbit-torque magnetic random access memory

Science.gov (United States)

Zhang, Yin; Yuan, H. Y.; Wang, X. S.; Wang, X. R.

2018-04-01

Spin-orbit-torque magnetic random access memory (SOT-MRAM) is a promising technology for the next generation of data storage devices. The main bottleneck of this technology is the high reversal current density threshold. This outstanding problem is now solved by a new strategy in which the magnitude of the driven current density is fixed while the current direction varies with time. The theoretical limit of minimal reversal current density is only a fraction (the Gilbert damping coefficient) of the threshold current density of the conventional strategy. The Euler-Lagrange equation for the fastest magnetization reversal path and the optimal current pulse is derived for an arbitrary magnetic cell and arbitrary spin-orbit torque. The theoretical limit of minimal reversal current density and current density for a GHz switching rate of the new reversal strategy for CoFeB/Ta SOT-MRAMs are, respectively, of the order of 105 A/cm 2 and 106 A/cm 2 far below 107 A/cm 2 and 108 A/cm 2 in the conventional strategy. Furthermore, no external magnetic field is needed for a deterministic reversal in the new strategy.

Phylemon 2.0: a suite of web-tools for molecular evolution, phylogenetics, phylogenomics and hypotheses testing.

Science.gov (United States)

Sánchez, Rubén; Serra, François; Tárraga, Joaquín; Medina, Ignacio; Carbonell, José; Pulido, Luis; de María, Alejandro; Capella-Gutíerrez, Salvador; Huerta-Cepas, Jaime; Gabaldón, Toni; Dopazo, Joaquín; Dopazo, Hernán

2011-07-01

Phylemon 2.0 is a new release of the suite of web tools for molecular evolution, phylogenetics, phylogenomics and hypotheses testing. It has been designed as a response to the increasing demand of molecular sequence analyses for experts and non-expert users. Phylemon 2.0 has several unique features that differentiates it from other similar web resources: (i) it offers an integrated environment that enables evolutionary analyses, format conversion, file storage and edition of results; (ii) it suggests further analyses, thereby guiding the users through the web server; and (iii) it allows users to design and save phylogenetic pipelines to be used over multiple genes (phylogenomics). Altogether, Phylemon 2.0 integrates a suite of 30 tools covering sequence alignment reconstruction and trimming; tree reconstruction, visualization and manipulation; and evolutionary hypotheses testing.

Phylemon 2.0: a suite of web-tools for molecular evolution, phylogenetics, phylogenomics and hypotheses testing

Science.gov (United States)

Sánchez, Rubén; Serra, François; Tárraga, Joaquín; Medina, Ignacio; Carbonell, José; Pulido, Luis; de María, Alejandro; Capella-Gutíerrez, Salvador; Huerta-Cepas, Jaime; Gabaldón, Toni; Dopazo, Joaquín; Dopazo, Hernán

2011-01-01

Phylemon 2.0 is a new release of the suite of web tools for molecular evolution, phylogenetics, phylogenomics and hypotheses testing. It has been designed as a response to the increasing demand of molecular sequence analyses for experts and non-expert users. Phylemon 2.0 has several unique features that differentiates it from other similar web resources: (i) it offers an integrated environment that enables evolutionary analyses, format conversion, file storage and edition of results; (ii) it suggests further analyses, thereby guiding the users through the web server; and (iii) it allows users to design and save phylogenetic pipelines to be used over multiple genes (phylogenomics). Altogether, Phylemon 2.0 integrates a suite of 30 tools covering sequence alignment reconstruction and trimming; tree reconstruction, visualization and manipulation; and evolutionary hypotheses testing. PMID:21646336

Analysis of surface dark current dependent upon surface passivation in APD based on GaAs

International Nuclear Information System (INIS)

Song, Hong Joo; Roh, Cheong Hyun; Lee, Jun Ho; Choi, Hong Goo; Hahn, Cheol-Koo; Kim, Dong Ho; Park, Jung Ho

2009-01-01

In this paper, we investigated the dependence of reverse dark current on two types of surface passivation, one of which is polyimide and the other is SiN x , for InAs quantum dots/GaAs separate absorption, charge, multiplication avalanche photodiode (SACM APD). From the experimental results, we found that dark current was dominated by surface current, and not bulk current. It was also noted that SiN x passivation has a surface current that is lower by three to nine times in magnitude than that in polyimide passivation in the whole range of bias. To analyze the difference in dark current due to the passivation types, we propose the theoretical current components. This shows that the dark current of both passivation types is mainly composed of generation–recombination (G–R) and tunneling components, originating from the surface. However, each component has a different magnitude for passivation types, which can be explained by carrier concentration and trap density. The dependence of dark current on temperature shows the different behaviors between passivation types and supports a theoretical description of current components

Five hypotheses concerning the fate of the Singapore issues in the Doha Round

OpenAIRE

Evenett, Simon J.

2017-01-01

At the Cancún Ministerial Conference, the members of the World Trade Organization (WTO) disagreed on whether to launch negotiations on multilateral disciplines concerning the four areas of government policy collectively known as the ‘Singapore issues'. This amounted to a decision not to expand the WTO's boundaries along these dimensions. In this paper, five hypotheses concerning the treatment of the Singapore issues by the WTO's membership are described and assessed. The implications of this ...

Gravitational Waves from Coalescing Binary Black Holes: Theoretical and Experimental Challenges

CERN Multimedia

CERN. Geneva

2010-01-01

(LIGO/VIRGO/GEO/...) is currently taking data near its planned sensitivity. Coalescing black hole binaries are among the most promising, and most exciting, gravitational wave sources for these detectors. The talk will review the theoretical and experimental challenges that must be met in order to successfully detect gravitational waves from coalescing black hole binaries, and to be able to reliably measure the physical parameters of the source (masses, spins, ...).

Improving the Validity of Quantitative Measures in Applied Linguistics Research

Science.gov (United States)

Purpura, James E.; Brown, James Dean; Schoonen, Rob

2015-01-01

In empirical applied linguistics research it is essential that the key variables are operationalized in a valid and reliable way, and that the scores are treated appropriately, allowing for a proper testing of the hypotheses under investigation. The current article addresses several theoretical and practical issues regarding the use of measurement…

Music Therapy for Posttraumatic Stress in Adults: A Theoretical Review

Science.gov (United States)

Landis-Shack, Nora; Heinz, Adrienne J.; Bonn-Miller, Marcel O.

2017-01-01

Music therapy has been employed as a therapeutic intervention to facilitate healing across a variety of clinical populations. There is theoretical and empirical evidence to suggest that individuals with trauma exposure and Posttraumatic Stress Disorder (PTSD), a condition characterized by enduring symptoms of distressing memory intrusions, avoidance, emotional disturbance, and hyperarousal, may derive benefits from music therapy. The current narrative review describes the practice of music therapy and presents a theoretically-informed assessment and model of music therapy as a tool for addressing symptoms of PTSD. The review also presents key empirical studies that support the theoretical assessment. Social, cognitive, and neurobiological mechanisms (e.g., community building, emotion regulation, increased pleasure, anxiety reduction) that promote music therapy’s efficacy as an adjunctive treatment for individuals with posttraumatic stress are discussed. It is concluded that music therapy may be a useful therapeutic tool to reduce symptoms and improve functioning among individuals with trauma exposure and PTSD, though more rigorous empirical study is required. In addition, music therapy may help foster resilience and engage individuals who struggle with stigma associated with seeking professional help. Practical recommendations for incorporating music therapy into clinical practice are offered along with several suggestions for future research. PMID:29290641

Studies in Theoretical and Applied Statistics

CERN Document Server

Pratesi, Monica; Ruiz-Gazen, Anne

2018-01-01

This book includes a wide selection of the papers presented at the 48th Scientific Meeting of the Italian Statistical Society (SIS2016), held in Salerno on 8-10 June 2016. Covering a wide variety of topics ranging from modern data sources and survey design issues to measuring sustainable development, it provides a comprehensive overview of the current Italian scientific research in the fields of open data and big data in public administration and official statistics, survey sampling, ordinal and symbolic data, statistical models and methods for network data, time series forecasting, spatial analysis, environmental statistics, economic and financial data analysis, statistics in the education system, and sustainable development. Intended for researchers interested in theoretical and empirical issues, this volume provides interesting starting points for further research.

How Realistic Are the Scientific Assumptions of the Neuroenhancement Debate? Assessing the Pharmacological Optimism and Neuroenhancement Prevalence Hypotheses

Directory of Open Access Journals (Sweden)

Stephan Schleim

2018-01-01

Full Text Available Since two decades, neuroenhancement is a major topic in neuroethics and still receives much attention in the scholarly literature as well as in public media. In contrast to high hopes at the beginning of the “Decade of the Brain” in the United States and Europe that we subsume under the “pharmacological optimism hypothesis,” recent evidence from clinical neuroscience suggests that developing drugs that make healthy people smarter is even more difficult than finding new treatments for patients with mental disorders. However, cognitive enhancing drugs even for patients with impaired intellectual performance have not been successfully developed yet and new drugs that might have a disruptive impact on this field are unlikely to be developed in the near future. Additionally, we discuss theoretical, empirical, and historical evidence to assess whether cognitive enhancement of the healthy is common or even epidemic and if its application will further increase in the near future, as suggested by the “neuroenhancement prevalence hypothesis.” Reports, surveys, and reviews from the 1930s until today indicate that psychopharmacological neuroenhancement is a fact but less common than often stated, particularly in the public media. Non-medical use of psychostimulants for the purpose of cognitive enhancement exists since at least 80 years and it might actually have been more common in the past than today. Therefore, we conclude that the pharmacological optimism hypothesis and neuroenhancement prevalence hypotheses have to be rejected and argue that the neuroenhancement debate should take the available evidence more into account.

Oxidation of organic pollutants on BDD anodes using modulated current electrolysis

International Nuclear Information System (INIS)

Panizza, M.; Kapalka, Agnieszka; Comninellis, Ch.

2008-01-01

In this paper, a theoretical model is presented for organic pollutants mineralization at high current efficiency (close to 100%) and low energy consumption on boron-doped diamond electrodes. The model is formulated for a perfect mixed electrochemical reactor operated as a batch recirculation system under multiple current steps, in which the applied current is adjusted during the electrolysis to be close to the limiting value. An experimental validation with the anodic oxidation of 3,4,5-trihydroxybenzoic acid is also provided. The results have shown that multiple current steps electrolysis and continuous current control allowed obtaining high oxidation rate and current efficiency

Oxidation of organic pollutants on BDD anodes using modulated current electrolysis

Energy Technology Data Exchange (ETDEWEB)

Panizza, M. [Department of Chemical and Process Engineering, University of Genoa, P.le J.F. Kennedy 1, 16129 Genova (Italy)], E-mail: marco.panizza@unige.it; Kapalka, Agnieszka [Institute of Chemical Sciences and Engineering, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Comninellis, Ch. [Institute of Chemical Sciences and Engineering, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)], E-mail: christos.comninellis@epfl.ch

2008-01-01

In this paper, a theoretical model is presented for organic pollutants mineralization at high current efficiency (close to 100%) and low energy consumption on boron-doped diamond electrodes. The model is formulated for a perfect mixed electrochemical reactor operated as a batch recirculation system under multiple current steps, in which the applied current is adjusted during the electrolysis to be close to the limiting value. An experimental validation with the anodic oxidation of 3,4,5-trihydroxybenzoic acid is also provided. The results have shown that multiple current steps electrolysis and continuous current control allowed obtaining high oxidation rate and current efficiency.

A Systematic Review of Current Understandings of Employability

Science.gov (United States)

Williams, Stella; Dodd, Lorna J.; Steele, Catherine; Randall, Raymond

2016-01-01

A theoretical framework is essential for the effective evaluation of employability. However, there are a wide range of definitions of employability coexisting in current literature. A review into existing ways in which employability has been conceptualised is needed to inform a better understanding of the nature of contributions made by various…

Theoretical chemistry advances and perspectives

CERN Document Server

Eyring, Henry

1980-01-01

Theoretical Chemistry: Advances and Perspectives, Volume 5 covers articles concerning all aspects of theoretical chemistry. The book discusses the mean spherical approximation for simple electrolyte solutions; the representation of lattice sums as Mellin-transformed products of theta functions; and the evaluation of two-dimensional lattice sums by number theoretic means. The text also describes an application of contour integration; a lattice model of quantum fluid; as well as the computational aspects of chemical equilibrium in complex systems. Chemists and physicists will find the book usef

Analytic description of tokamak equilibrium sustained by high fraction bootstrap current

International Nuclear Information System (INIS)

Shi Bingren

2002-01-01

Recently, to save the current drive power and to obtain more favorable confinement merit for tokamak reactor, large faction bootstrap current sustained equilibrium has attracted great interests both theoretically and experimentally. An powerful expanding technique and the tokamak ordering are used to expand the Grad-Shafranov equation to obtain a series of ordinary differential equations which allow for different sets of input parameters. The fully bootstrap current sustained tokamak equilibria are then solved analytically

Theoretical and experimental study of fenofibrate and simvastatin

Science.gov (United States)

Nicolás Vázquez, Inés; Rodríguez-Núñez, Jesús Rubén; Peña-Caballero, Vicente; Ruvalcaba, Rene Miranda; Aceves-Hernandez, Juan Manuel

2017-12-01

Fenofibrate, an oral fibrate lipid lowering agent, and simvastatin, which reduces plasma levels of low-density lipoprotein cholesterol, are active pharmaceutical ingredients (APIs), currently in the market. We characterized these APIs by thermal analysis and conducted X-ray powder diffraction techniques. Studies should be carried out in the formulation stage before the final composition of a polypill may be established. Thus, it was found in thermochemical studies that both compounds present no chemical interactions in an equimolar mixture of solid samples at room temperature. Theoretical studies were employed to determine possible interactions between fenofibrate and simvastatin. A very weak intramolecular hydrogen bond is formed between the hydroxyl group (O5H5) of the simvastatin with chlorine and carbonyl group (C11O4, C1O2) of the fenofibrate molecule. These weak energy hydrogen bonds have no effect on the chemical stability of the compounds studied. The results were obtained using Density Functional Theory methods; particularly the BPE1BPE and B3LYP functional and 6-31++G** basis set. The values of energy show good approximation when are compared with similar calculations previously reported. Infrared spectra of monomers and dimers were obtained via theoretical calculations.

Theoretical study of near-threshold electron-molecule scattering

International Nuclear Information System (INIS)

Morrison, M.A.

1989-01-01

We have been engaged in carrying out a foundation study on problems pertaining to near-threshold nuclear excitations in e-H 2 scattering. The primary goals of this study are: to investigate the severity and nature of the anticipated breakdown of the adiabatic-nuclei (AN) approximation, first for rotation only (in the rigid-rotator approximation), and then for vibration; to determine a data base of accurate ab initio cross sections for this important system; to implement and test accurate, computationally-tractable model potentials for exchange and polarization effects; and to begin the exploration of alternative scattering theories for near-threshold collisions. This study has provided a well-defined theoretical context for our future investigations. Second, it has enabled us to identify and quantify several serious problems in the theory of near-threshold electron-molecule scattering that demand attention. And finally, it has led to the development of some of the theoretical and computational apparatus that will form the foundation of future work. In this report, we shall review our progress to date, emphasizing work completed during the current contract year. 17 refs., 5 figs., 1 tab

Electric Currents along Astrophysical Jets

Directory of Open Access Journals (Sweden)

Ioannis Contopoulos

2017-10-01

Full Text Available Astrophysical black holes and their surrounding accretion disks are believed to be threaded by grand design helical magnetic fields. There is strong theoretical evidence that the main driver of their winds and jets is the Lorentz force generated by these fields and their associated electric currents. Several researchers have reported direct evidence for large scale electric currents along astrophysical jets. Quite unexpectedly, their directions are not random as would have been the case if the magnetic field were generated by a magnetohydrodynamic dynamo. Instead, in all kpc-scale detections, the inferred electric currents are found to flow away from the galactic nucleus. This unexpected break of symmetry suggests that a battery mechanism is operating around the central black hole. In the present article, we summarize observational evidence for the existence of large scale electric currents and their associated grand design helical magnetic fields in kpc-scale astrophysical jets. We also present recent results of general relativistic radiation magnetohydrodynamic simulations which show the action of the Cosmic Battery in the vicinity of astrophysical black holes.

Statistical analysis of hypotheses on the cointegrating relations in the I(2) model

DEFF Research Database (Denmark)

Johansen, Søren

2006-01-01

The cointegrated vector autoregressive model for I(2) variables is a non-linear parametric restriction on the linear I(2) regression model for variables of order I(0), I(1) and I(2). In this paper we discuss non-linear submodels given by smooth parametrizations. We give conditions on the parametr......) and the reformulation is applied to show that some hypotheses on the cointegrating coefficients in the cointegrated I(2) model give asymptotic ¿² inference....

Department of Theoretical Physics - Overview

International Nuclear Information System (INIS)

Kwiecinski, J.

2002-01-01

Full text: Research activity of the Department of Theoretical Physics concerns theoretical high energy and elementary particle physics, intermediate energy particle physics, theoretical nuclear physics, theory of nuclear matter, theory of quark-gluon plasma and of relativistic heavy ion collisions, theoretical astrophysics and general physics. There is some emphasis on the phenomenological applications of the theoretical research yet the more formal problems are also considered. The detailed summary of the research projects and of the results obtained in various fields is given in the abstracts. Our Department successfully collaborates with other Departments of the Institute as well as with several scientific institutions both in Poland and abroad. In particular, members of our Department participate in the EC network which allows for the mobility of researchers. Several members of our Department have also participated in the research projects funded by the State Committee for Scientific Research. Besides pure research, members of our Department are also involved in graduate and undergraduate teaching activity both at our Institute and at other academic institutions in Cracow. At present, eight students are working towards their Ph.D. degrees under the supervision of senior members of the Department. (author)

Department of Theoretical Physics - Overview

International Nuclear Information System (INIS)

Kwiecinski, J.

2001-01-01

Full text: Research activity of the Department of Theoretical Physics concerns theoretical high-energy and elementary particle physics, intermediate energy particle physics, theoretical nuclear physics, theory of nuclear matter, theory of quark-gluon plasma and relativistic heavy-ion collisions, theoretical astrophysics and general physics. There is some emphasis on the phenomenological applications of the theoretical research yet more formal problems are also considered. A detailed summary of the research projects and of the results obtained in various field is given in the abstracts. Our Department actively collaborates with other Departments of the Institute as well as with several scientific institutions both in Poland and abroad. In particular, members of our Department participate in the EC network, which stimulates the mobility of researchers. Several members of our Department also participated in the research projects funded by the Polish Committee for Scientific Research (KBN). Besides pure research, members of our Department are also involved in graduate and up graduate teaching activity at our Institute as well as at other academic institution in Cracow. At present nine students are working on their Ph.D. degrees under the supervision of senior members of the Department. (author)

Ultra Low Voltage Class AB Switched Current Memory Cells Based on Floating Gate Transistors

DEFF Research Database (Denmark)

Mucha, Igor

1999-01-01

current memory cells were designed using a CMOS process with threshold voltages V-T0n = \\V-T0p\\ = 0.9 V for the n- and p-channel devices. Both hand calculations and PSPICE simulations showed that the designed example switched current memory cell allowed a maximum signal range better than +/-18 mu......A proposal for a class AB switched current memory cell, suitable for ultra-low-voltage applications is presented. The proposal employs transistors with floating gates, allowing to build analog building blocks for ultralow supply voltage operation also in CMOS processes with high threshold voltages....... This paper presents the theoretical basis for the design of "floating-gate'' switched current memory cells by giving a detailed description and analysis of the most important impacts degrading the performance of the cells. To support the theoretical assumptions circuits based on "floating-gate'' switched...

Nuclear Fermi Dynamics: physical content versus theoretical approach

International Nuclear Information System (INIS)

Griffin, J.J.

1977-01-01

Those qualitative properties of nuclei, and of their energetic collisions, which seem of most importance for the flow of nuclear matter are listed and briefly discussed. It is suggested that nuclear matter flow is novel among fluid dynamical problems. The name, Nuclear Fermi Dynamics, is proposed as an appropriate unambiguous label. The Principle of Commensurability, which suggests the measurement of the theoretical content of an approach against its expected predictive range is set forth and discussed. Several of the current approaches to the nuclear matter flow problem are listed and subjected to such a test. It is found that the Time-Dependent Hartree-Fock (TDHF) description, alone of all the major theoretical approaches currently in vogue, incorporates each of the major qualitative features within its very concise single mathematical assumption. Some limitations of the conventional TDHF method are noted, and one particular defect is discussed in detail: the Spurious Cross Channel Correlations which arise whenever several asymptotic reaction channels must be simultaneously described by a single determinant. A reformulated Time-Dependent-S-Matrix Hartree-Fock Theory is proposed, which obviates this difficulty. It is noted that the structure of TD-S-HF can be applied to a more general class of non-linear wave mechanical problems than simple TDHF. Physical requirements minimal to assure that TD-S-HF represents a sensible reaction theory are utilized to prescribe the definition of acceptable asymptotic channels. That definition, in turn, defines the physical range of the TD-S-HF theory as the description of collisions of certain mathematically well-defined objects of mixed quantal and classical character, the ''TDHF droplets.''

Cancer risks near nuclear facilities: the importance of research design and explicit study hypotheses.

Science.gov (United States)

Wing, Steve; Richardson, David B; Hoffmann, Wolfgang

2011-04-01

In April 2010, the U.S. Nuclear Regulatory Commission asked the National Academy of Sciences to update a 1990 study of cancer risks near nuclear facilities. Prior research on this topic has suffered from problems in hypothesis formulation and research design. We review epidemiologic principles used in studies of generic exposure-response associations and in studies of specific sources of exposure. We then describe logical problems with assumptions, formation of testable hypotheses, and interpretation of evidence in previous research on cancer risks near nuclear facilities. Advancement of knowledge about cancer risks near nuclear facilities depends on testing specific hypotheses grounded in physical and biological mechanisms of exposure and susceptibility while considering sample size and ability to adequately quantify exposure, ascertain cancer cases, and evaluate plausible confounders. Next steps in advancing knowledge about cancer risks near nuclear facilities require studies of childhood cancer incidence, focus on in utero and early childhood exposures, use of specific geographic information, and consideration of pathways for transport and uptake of radionuclides. Studies of cancer mortality among adults, cancers with long latencies, large geographic zones, and populations that reside at large distances from nuclear facilities are better suited for public relations than for scientific purposes.

Ion beams from high-current PF facilities

Energy Technology Data Exchange (ETDEWEB)

Sadowski, M [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland)

1997-12-31

Pulsed beams of fast deuterons and impurity or admixture ions emitted from high-current PF-type facilities operated in different laboratories are dealt with. A short comparative analysis of time-integrated and time-resolved studies is presented. Particular attention is paid to the microstructure of such ion beams, and to the verification of some theoretical models. (author). 5 figs., 19 refs.

The Theoretical Aspects of Controlling of Marketing in Enterprise

Directory of Open Access Journals (Sweden)

Liakh Inna S.

2017-07-01

Full Text Available The article is aimed at generalizing the theoretical provisions on controlling of marketing in enterprise: to clarify the place of controlling of marketing within the management system, constituents, goals, tasks, and functions. The controlling of marketing was considered in terms of concepts such as management of enterprise, management of marketing, operative management of marketing, controlling, strategic and operational controlling of marketing, and operative management of marketing costs. The constituents and tools of controlling of marketing at the strategic and the operational levels have been defined. The definition of operative controlling of marketing has been revised, which emphasizes managerial decision-making about marketing costs, taking account of current situation and optimality of such costs as to purposes of enterprise. A systematic approach to studying this issue provides a holistic view of controlling of marketing within the enterprise management system. A study on the theoretical aspects of controlling of marketing as a modern management concept will make it possible to approach the issue of decision-making on marketing activity in a holistic manner.

Graphene-Based FET Detector for E. coli K12 Real-Time Monitoring and Its Theoretical Analysis

Directory of Open Access Journals (Sweden)

Jieyi Zhu

2016-01-01

Full Text Available This paper presents a theoretical analysis for a graphene-based FET real-time detector of the target bacteria E. coli K12. The motivation for this study is to design a sensor device for detection of bacteria in food and water in order to guarantee food safety. Graphene is chosen as our material for sensor design, which has outstanding electrical, physical, and optical performance. In our sensor structure, graphene-based solution gate field effect transistor (FET is the device model; fabrication and functionalization protocol are presented together in this paper. What is more, a real-time signal display system is the accompanied equipment for our designed biosensor device. In this system, the sensor bias current signal Ids would change obviously when the target bacteria are attached to the sensor surface. And the bias current Ids increases when the E. coli concentration increases. In the latter part, a theoretical interpretation of the sensor signal is to explain the bias current Ids increasing after the E. coli K12 attachment.

ENTREPRENEURIAL LEADERSHIP: A THEORETICAL FRAMEWORK

Directory of Open Access Journals (Sweden)

Yusuf ESMER

2017-12-01

Full Text Available Today, having just leadership or entrepreneurship qualities by business managers is not enough for success of enterprises. Managers need to have both leadership and entrepreneurship qualities in order to be successful. At this point, the concept of entrepreneurial leadership emerges. Entrepreneurial leadership is a new and modern type of leadership that is a combination of leadership qualities and spirit of entrepreneurship. In addition, entrepreneurial leadership is creating new products, new processes and expansion opportunities in existing businesses, working in social institutions and dealing with ignored social issues, participating in social and political movements, contributing to the change of current services and policies implemented by civil society organizations and governments. In recent times, entrepreneurial leadership has become a new phenomenon in business management that needs to be discussed. In this regard, in this study, the importance of entrepreneurial leadership is emphasized by examining the concept of entrepreneurial leadership within a theoretical framework.

Solid surfaces : some theoretical aspects

International Nuclear Information System (INIS)

Das, M.P.

1978-01-01

An appraisal of the current situation concerning some of the theoretical aspects of solid surfaces is presented. First of all the characterization of the surfaces that involves the surface geometry and atomic composition for both the clean and adsorbed surfaces is discussed. Under this, the methods for determining the surface structure (such as low energy electron diffraction, field electron and field ion microscopy, photo emission spectroscopy and atomic scattering) and methods for determining the surface composition by the Auger electron spectroscopy are outlined. In the second part, emphasis is on the electronic structure of the clean and adsorbed surfaces. The measurements of ultra-violet and X-ray photo electron spectra are shown to yield the information about the surface electronic structure. In this context the many body effects such as, shake-up and relaxation energy etc. are discussed. Finally the status of the theory in relation to the experiments on angular resolved and polarization dependent photo emission are presented. (auth.)

[An increase in allergic diseases in childhood--current hypotheses and possible prevention].

Science.gov (United States)

Kurz, Herbert; Riedler, Jose

2003-01-01

During the last few decades there has ben a significant rise in the prevalence of allergic diseases such as asthma, hay fever and atopic dermatitis. Epidemiological studies strongly suggest that this increase is real and not due to changes in diagnostic labelling. It has become increasingly clear that a complex interplay between genetic and environmental factors account for this phenomenon. Genetically predisposed individuals are at an increased susceptibility to develop asthma or other allergic diseases when exposed to certain environmental or lifestyle factors. Particularly passive smoking has been shown to increase the risk for asthma in many studies and for atopy at least in some studies. This association is less clear for the exposure to sulfur dioxide, particulate matter, diesel exhaust and ozone. Lifestyle factors like socioeconomic status, sib-ship size, early childhood infections, dietary habits, growing up in antroposophic families or on a farm are more and more realised to be of great relevance for the development of allergic conditions. At the moment, there is a lot of uncertainty about which recommendations should be given for primary prevention. Recent studies have challenged the old paradigma that avoidance of early allergen contact could prevent the development of allergic disease. However, there is consensus that avoidance of smoking during pregnancy and avoidance of passive smoking during childhood should be recommended for primary prevention of asthma.

Charged Current Quasielastic Analysis from MINERνA

Energy Technology Data Exchange (ETDEWEB)

Ghosh, Anushree [Rio de Janeiro, CBPF

2015-08-01

The MINERνA detector situated in Fermilab, is designed to make precision cross-section measurements for scattering processes on various nuclei. In this proceeding, the results of the charged current quasi-elastic (CCQE) analysis using lepton kinematics and with proton kinematics have been presented. Comparison of these with theoretical models suggested that further studies are required to include the additional nuclear effects in the current simulations. The first direct measurement of electron-neutrino quasielastic-like scattering in the few-GeV region of incident neutrino energy has also been presented. All three analyses, discussed here, are carried out on hydrocarbon target.

Heavy-Ion Reactions: a current awareness bulletin

International Nuclear Information System (INIS)

Kinser, W.H.

1985-01-01

This current awareness bulletin announces on a semimonthly basis the current worldwide information entered into the Energy Data Base on theoretical and experimental studies (including instrumentation) of heavy-ion (A > 4) nuclear reactions for nuclear structure studies; for producing new isotopes and superheavy elements for nuclear, atomic, and chemical properties studies; for understanding quantum chromodynamics as an exact theory of the strong nuclear force; and for studying the equations of state and phases of nuclear matter (pion condensate and quark matter) of special interest in astrophysics, and cosmology. An abstract is included with each citation. Regular publication began in January 1985

Current scaling of plasma focus devices

International Nuclear Information System (INIS)

Schiuma, C.; Herold, H.; Kaeppeler, H.J.; Shakhatre, M.; Auluck, S.K.H.

1990-03-01

In continuation of the work by G. Decker et al. on current and neutron yield scaling of plasma focus devices an analytical solution for the circuit equation (with resistance R = 0) in the compression phase was derived. Together with the solution for the rundown phase from G. Decker et al, which was extended for finite resistance (R ≠ 0), there follows an analytical scaling theory for maximum and pinch currents. At the same time there exists the possibility to discuss the influence of finite resistance on current variation and scaling parameters. The model solutions were checked out by numerical integrations of the current equation. While at the beginning of the rundown phase the ohmic resistance cannot be neglected (the magnitude R/L plays an important role), its influence at the end of the rundown phase and in the compression phase is negligible. The theoretically determined values are compared with the results of numerous probe measurements. (orig.)

Theoretical White Dwarf Spectra on Demand: TheoSSA

Science.gov (United States)

Ringat, E.; Rauch, T.

2010-11-01

In the last decades, a lot of progress was made in spectral analysis. The quality (e.g. resolution, S/N ratio) of observed spectra has improved much and several model-atmosphere codes were developed. One of these is the ``Tübingen NLTE Model-Atmosphere Package'' (TMAP), that is a highly developed program for the calculation of model atmospheres of hot, compact objects. In the framework of the German Astrophysical Virtual Observatory (GAVO), theoretical spectral energy distributions (SEDs) can be downloaded via TheoSSA. In a pilot phase, TheoSSA is based on TMAP model atmospheres. We present the current state of this VO service.

Current transport modeling and experimental study of THz room temperature ballistic deflection transistors

Energy Technology Data Exchange (ETDEWEB)

Kaushal, Vikas; Margala, Martin [Department of Electrical and Computer Engineering, University of Massachusetts Lowell, MA, 01854 (United States); Yu Qiaoyan; Ampadu, Paul; Guarino, Gregg; Sobolewski, Roman, E-mail: vikas_kaushal@student.uml.ed [Department of Electrical and Computer Engineering, University of Rochester, NY, 14627 (United States)

2009-11-15

In this paper, two different theoretical models, Comsol Multiphysics{sup TM} (a Finite Element Analysis tool), and a field solver Atlas/Blaze from Silvaco, are compared qualitatively to study the effect of the deflector position, its size and electric field on the charge transport and its distribution along the channel, resulting in current outputs and leakages in ballistic deflection transistors (BDT). Silvaco simulations and experimental results were then used to study the lateral charge transport as a result of variation in electric field distribution, which controls the charge current along the channel in BDT. The electric field dependence of gain is also studied with experimental and theoretical results.

Current transport modeling and experimental study of THz room temperature ballistic deflection transistors

International Nuclear Information System (INIS)

Kaushal, Vikas; Margala, Martin; Yu Qiaoyan; Ampadu, Paul; Guarino, Gregg; Sobolewski, Roman

2009-01-01

In this paper, two different theoretical models, Comsol Multiphysics TM (a Finite Element Analysis tool), and a field solver Atlas/Blaze from Silvaco, are compared qualitatively to study the effect of the deflector position, its size and electric field on the charge transport and its distribution along the channel, resulting in current outputs and leakages in ballistic deflection transistors (BDT). Silvaco simulations and experimental results were then used to study the lateral charge transport as a result of variation in electric field distribution, which controls the charge current along the channel in BDT. The electric field dependence of gain is also studied with experimental and theoretical results.

Stator Current Harmonic Reduction in a Novel Half Quasi-Z-Source Wind Power Generation System

Directory of Open Access Journals (Sweden)

Shoudao Huang

2016-09-01

Full Text Available The generator stator current gets distorted with unacceptable levels of total harmonic distortion (THD because impedance-source wind power generation systems use three-phase diode rectifiers. The stator current harmonics will cause increasing losses and torque ripple, which reduce the efficiency and stability of the system. This paper proposes a novel half quasi-Z-source inverter (H-qZSI for grid-connected wind power generation systems, which can reduce the generator stator current harmonics a great deal. When H-qZSI operates in the shoot-through zero state, the derivative of the generator stator current is only determined by the instantaneous value of the generator stator voltage, so the nonlinear relationship between generator stator current and stator voltage is improved compared with the traditional impedance-source inverter. Theoretically, it is indicated that the stator current harmonics can be reduced effectively by means of the proposed H-qZSI. Finally, simulation and experimental results are given to verify the theoretical analysis.

New theoretical investigation resolving discrepancies of atomic form factors and attenuation coefficients in the near-edge soft x-ray regime

International Nuclear Information System (INIS)

Chantler, C.T.

2000-01-01

Full text: Reliable knowledge of the complex X-ray form factor and the photoelectric attenuation coefficient is required for crystallography, medical diagnosis, refractive index studies and XAFS. Discrepancies between currently used theoretical approaches of 200% exist for numerous elements from 1 keV to 3 keV X-ray energies. This work derives new theoretical results in near-edge soft X-ray regions and improves upon the theoretical uncertainty in these regions by a factor of 10. This work was also reported in J.Phys.Chem.Ref.Data (2000)

Capacitance measurement of Josephson tunnel junctions with microwave-induced dc quasiparticle tunneling currents

International Nuclear Information System (INIS)

Hamasaki, K.; Yoshida, K.; Irie, F.; Enpuku, K.

1982-01-01

The microwave response of the dc quasiparticle tunneling current in Josephson tunnel junctions, where the Josephson current is suppressed by an external magnetic field, has been studied quantitatively in order to clarify its characteristics as a probe for the measurement of the junction capacitance. Extensive experiments for both small and long junctions are carried out for distinguishing between microwave behaviors of lumped and distributed constant junctions. It is shown that the observed voltage dependence of the dc quasiparticle tunneling current modified by an applied rf field is in good agreement with a theoretical result which takes into account the influence of the microwave circuit connected to the junction. The comparison between theory and experiment gives the magnitude of the internal rf field in the junction. Together with the applied rf field, this internal rf field leads to the junction rf impedance which is dominated by the junction capacitance in our experimental condition. In the case of lumped junctions, this experimental rf impedance is in reasonable agreement with the theoretical one with the junction capacitance estimated from the Fiske step of the distributed junction fabricated on the same substrate; the obtained ratio of the experimental impedance to the theoretical one is approximately 0.6--1.7. In the case of distributed junctions, however, experimental values of their characteristic impedances are approximately 0.2--0.3 of theoretical values calculated by assuming the one-dimensional junction model and taking account of the standing-wave effect in the junction

First demonstration of HF-driven ionospheric currents

Science.gov (United States)

Papadopoulos, K.; Chang, C.-L.; Labenski, J.; Wallace, T.

2011-10-01

The first experimental demonstration of HF driven currents in the ionosphere at low ELF/ULF frequencies without relying in the presence of electrojets is presented. The effect was predicted by theoretical/computational means in a recent letter and given the name Ionospheric Current Drive (ICD). The effect relies on modulated F-region HF heating to generate Magneto-Sonic (MS) waves that drive Hall currents when they reach the E-region. The Hall currents inject ELF waves into the Earth-Ionosphere waveguide and helicon and Shear Alfven (SA) waves in the magnetosphere. The proof-of-concept experiments were conducted using the HAARP heater in Alaska under the BRIOCHE program. Waves between 0.1-70 Hz were measured at both near and far sites. The letter discusses the differences between ICD generated waves and those relying on modulation of electrojets.

How and when do expert emergency physicians generate and evaluate diagnostic hypotheses? A qualitative study using head-mounted video cued-recall interviews.

Science.gov (United States)

Pelaccia, Thierry; Tardif, Jacques; Triby, Emmanuel; Ammirati, Christine; Bertrand, Catherine; Dory, Valérie; Charlin, Bernard

2014-12-01

The ability to make a diagnosis is a crucial skill in emergency medicine. Little is known about the way emergency physicians reach a diagnosis. This study aims to identify how and when, during the initial patient examination, emergency physicians generate and evaluate diagnostic hypotheses. We carried out a qualitative research project based on semistructured interviews with emergency physicians. The interviews concerned management of an emergency situation during routine medical practice. They were associated with viewing the video recording of emergency situations filmed in an "own-point-of-view" perspective. The emergency physicians generated an average of 5 diagnostic hypotheses. Most of these hypotheses were generated before meeting the patient or within the first 5 minutes of the meeting. The hypotheses were then rank ordered within the context of a verification procedure based on identifying key information. These tasks were usually accomplished without conscious effort. No hypothesis was completely confirmed or refuted until the results of investigations were available. The generation and rank ordering of diagnostic hypotheses is based on the activation of cognitive processes, enabling expert emergency physicians to process environmental information and link it to past experiences. The physicians seemed to strive to avoid the risk of error by remaining aware of the possibility of alternative hypotheses as long as they did not have the results of investigations. Understanding the diagnostic process used by emergency physicians provides interesting ideas for training residents in a specialty in which the prevalence of reasoning errors leading to incorrect diagnoses is high. Copyright © 2014 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

The N2HDM under theoretical and experimental scrutiny

Energy Technology Data Exchange (ETDEWEB)

Mühlleitner, Margarete [Institute for Theoretical Physics, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Sampaio, Marco O.P. [Departamento de Física, Universidade de Aveiro and CIDMA, Campus de Santiago, 3810-183 Aveiro (Portugal); Santos, Rui [ISEL - Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, 1959-007 Lisboa (Portugal); Centro de Física Teórica e Computacional, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Edifício C8, 1749-016 Lisboa (Portugal); Wittbrodt, Jonas [Institute for Theoretical Physics, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, D-22607 Hamburg (Germany)

2017-03-17

The N2HDM is based on the CP-conserving 2HDM extended by a real scalar singlet field. Its enlarged parameter space and its fewer symmetry conditions as compared to supersymmetric models allow for an interesting phenomenology compatible with current experimental constraints, while adding to the 2HDM sector the possibility of Higgs-to-Higgs decays with three different Higgs bosons. In this paper the N2HDM is subjected to detailed scrutiny. Regarding the theoretical constraints we implement tests of tree-level perturbativity and vacuum stability. Moreover, we present, for the first time, a thorough analysis of the global minimum of the N2HDM. The model and the theoretical constraints have been implemented in ScannerS, and we provide N2HDECAY, a code based on HDECAY, for the computation of the N2HDM branching ratios and total widths including the state-of-the-art higher order QCD corrections and off-shell decays. We then perform an extensive parameter scan in the N2HDM parameter space, with all theoretical and experimental constraints applied, and analyse its allowed regions. We find that large singlet admixtures are still compatible with the Higgs data and investigate which observables will allow to restrict the singlet nature most effectively in the next runs of the LHC. Similarly to the 2HDM, the N2HDM exhibits a wrong-sign parameter regime, which will be constrained by future Higgs precision measurements.

The N2HDM under theoretical and experimental scrutiny

International Nuclear Information System (INIS)

Mühlleitner, Margarete; Sampaio, Marco O.P.; Santos, Rui; Wittbrodt, Jonas

2017-01-01

The N2HDM is based on the CP-conserving 2HDM extended by a real scalar singlet field. Its enlarged parameter space and its fewer symmetry conditions as compared to supersymmetric models allow for an interesting phenomenology compatible with current experimental constraints, while adding to the 2HDM sector the possibility of Higgs-to-Higgs decays with three different Higgs bosons. In this paper the N2HDM is subjected to detailed scrutiny. Regarding the theoretical constraints we implement tests of tree-level perturbativity and vacuum stability. Moreover, we present, for the first time, a thorough analysis of the global minimum of the N2HDM. The model and the theoretical constraints have been implemented in ScannerS, and we provide N2HDECAY, a code based on HDECAY, for the computation of the N2HDM branching ratios and total widths including the state-of-the-art higher order QCD corrections and off-shell decays. We then perform an extensive parameter scan in the N2HDM parameter space, with all theoretical and experimental constraints applied, and analyse its allowed regions. We find that large singlet admixtures are still compatible with the Higgs data and investigate which observables will allow to restrict the singlet nature most effectively in the next runs of the LHC. Similarly to the 2HDM, the N2HDM exhibits a wrong-sign parameter regime, which will be constrained by future Higgs precision measurements.

Set-theoretic methods in control

CERN Document Server

Blanchini, Franco

2015-01-01

The second edition of this monograph describes the set-theoretic approach for the control and analysis of dynamic systems, both from a theoretical and practical standpoint.  This approach is linked to fundamental control problems, such as Lyapunov stability analysis and stabilization, optimal control, control under constraints, persistent disturbance rejection, and uncertain systems analysis and synthesis.  Completely self-contained, this book provides a solid foundation of mathematical techniques and applications, extensive references to the relevant literature, and numerous avenues for further theoretical study. All the material from the first edition has been updated to reflect the most recent developments in the field, and a new chapter on switching systems has been added.  Each chapter contains examples, case studies, and exercises to allow for a better understanding of theoretical concepts by practical application. The mathematical language is kept to the minimum level necessary for the adequate for...

Spin current through quantum-dot spin valves

International Nuclear Information System (INIS)

Wang, J; Xing, D Y

2006-01-01

We report a theoretical study of the influence of the Coulomb interaction on the equilibrium spin current in a quantum-dot spin valve, in which the quantum dot described by the Anderson impurity model is coupled to two ferromagnetic leads with noncollinear magnetizations. In the Kondo regime, electrons transmit through the quantum dot via higher-order virtual processes, in which the spin of either lead electrons or a localized electron on the quantum dot may reverse. It is found that the magnitude of the spin current decreases with increasing Coulomb interactions due to spin flip effects on the dot. However, the spatial direction of the spin current remains unchanged; it is determined only by the exchange coupling between two noncollinear magnetizations

Tuning of tunneling current noise spectra singularities by localized states charging

OpenAIRE

Mantsevich, V. N.; Maslova, N. S.

2008-01-01

We report the results of theoretical investigations of tunneling current noise spectra in a wide range of applied bias voltage. Localized states of individual impurity atoms play an important role in tunneling current noise formation. It was found that switching "on" and "off" of Coulomb interaction of conduction electrons with two charged localized states results in power law singularity of low-frequency tunneling current noise spectrum ($1/f^{\\alpha}$) and also results on high frequency com...

The influence of interband tunneling on leakage current in manganite/titanate heterojunction

International Nuclear Information System (INIS)

Han Peng; Jia Jinfeng

2008-01-01

The behavior of leakage current at reverse bias in p-La 0.9 Sr 0.1 MnO 3 /n-SrNb 0.01 Ti 0.99 O 3 heterojunction has been theoretically studied by calculating interband tunneling current with various doping densities and temperatures. Our results reveal that the reduction of leakage current with decrease of doping density and increase of temperature originates from properties of interband tunneling

Masticatory-stress hypotheses and the supraorbital region of primates.

Science.gov (United States)

Hylander, W L; Picq, P G; Johnson, K R

1991-09-01

The purpose of this study is to test various masticatory-stress hypotheses about the evolution and function of well-developed browridges of higher primates. This was done by measuring and analyzing patterns of in vivo bone strain recorded from three-element rosette strain gages bonded to the supraorbital region and to other portions of the bony face of Macaca fascicularis and Papio anubis during mastication and incision. The magnitude and direction of the principal strains recorded support Endo's hypothesis that the supraorbital region during mastication and incision is bent in the frontal plane (Endo, 1966). Our data do not, however, support his hypothesis that the supraorbital region is bent more during incision than during mastication. The data also demonstrate that overall levels of supraorbital strain are not larger in more prognathic subjects. Most importantly, the data indicate that the supraorbital region of nonhuman catarrhines is strained very little during mastication and incision. This indicates that there is much more supraorbital bone than is necessary both to counter masticatory loads and to provide an adequate safety factor to failure for these loads. This in turn suggests that the macaque and baboon browridges can be considerably reduced in size and still maintain these required structural characteristics. Thus, our experiments provide no support whatsoever for those hypotheses that directly link browridge morphology to masticatory stress (cf. Endo, 1966; Russell, 1983, 1985). A recent review of Endo's original work indicates that this latter statement is also true for humans (Picq and Hylander, 1989). We conclude, therefore, that there is no good reason to believe that enlarged browridges in living and/or fossil primates are structural adaptations to counter intense masticatory forces. The evolution of browridge morphology in primates is best explained on the basis of factors related to the position of the brain relative to the orbits (Moss and

The Association between Relational Aggression and Perceived Popularity in Early Adolescence: A Test of Competing Hypotheses

Science.gov (United States)

Gangel, Meghan J.; Keane, Susan P.; Calkins, Susan D.; Shanahan, Lilly; O'Brien, Marion

2017-01-01

This study examined two competing hypotheses regarding the moderators of the association between relational aggression and peer status in early adolescence. The "mitigation relational aggression" hypothesis examined whether positive social behaviors reduced the negative effects of relational aggression, thus amplifying the association…

Total Cross Sections at current/Future Colliders, conventional models and QCD

CERN Document Server

Fazal-e-Aleem, M

1999-01-01

Rise in total cross sections for elastic scattering generated immense interest both for experimental measurements and theoretical investigations. How will total cross section behave at LHC and Cosmic Ray energies is therefore in the limelight of our future measurements. Theoretical studies become even more interesting when we take into consideration the ratio of real and imaginary parts of the scattering amplitudes. We will briefly undertake the current results and future prospects in the light of conventional as well as QCD-based phenomenology.

Coopersmith Self-Esteem: Two Different Hypothesized Factor Models--Both Acceptable for the Same Data Structure.

Science.gov (United States)

Hofmann, Rich; Sherman, Larry

Using data from 135 sixth-, seventh-, and eighth-graders between 11 and 15 years old attending a middle school in a suburban Southwest Ohio school district, two hypothesized models of the factor structures for the Coopersmith Self-Esteem Inventory were tested. One model represents the original Coopersmith factor structure, and the other model is…

Development of a patient-reported outcome measure of recovery after abdominal surgery: a hypothesized conceptual framework.

Science.gov (United States)

Alam, Roshni; Figueiredo, Sabrina M; Balvardi, Saba; Nauche, Bénédicte; Landry, Tara; Lee, Lawrence; Mayo, Nancy E; Feldman, Liane S; Fiore, Julio F

2018-05-17

We initiated a research program to develop a novel patient-reported outcome measure (PROM) to assess postoperative recovery from the perspective of abdominal surgery patients. In light of FDA recommendations, the first stage of our program aimed to, based on previous literature and expert input, develop a hypothesized conceptual framework portraying the health domains that are potentially relevant to the process of recovery after abdominal surgery. This study was conducted in three phases: (1) systematic review to identify PROMs with measurement properties appraised in the context of recovery after abdominal surgery, (2) content analysis to categorize the health domains covered by the PROMs according to the ICF, and (3) two-round Delphi study to gain expert input regarding which of these health domains are relevant to the process of recovery. Participants were experts in perioperative care identified through two major surgical societies (35 invited). The systematic review identified 19 PROMs covering 66 ICF domains. 23 experts (66%) participated in the Delphi process. After Round 2, experts agreed that 22 health domains (8 body functions, 14 activities and participation) are potentially relevant to the process of recovery after abdominal surgery. These domains were organized into a diagram, representing our hypothesized conceptual framework. This hypothesized conceptual framework is an important first step in our research program and will be further refined based on in-depth qualitative interviews with patients. The sound methodological approach used to derive this framework may be valuable for studies aimed to develop PROMs according to FDA standards.

Current trends in nursing theories.

Science.gov (United States)

Im, Eun-Ok; Chang, Sun Ju

2012-06-01

To explore current trends in nursing theories through an integrated literature review. The literature related to nursing theories during the past 10 years was searched through multiple databases and reviewed to determine themes reflecting current trends in nursing theories. The trends can be categorized into six themes: (a) foci on specifics; (b) coexistence of various types of theories; (c) close links to research; (d) international collaborative works; (e) integration to practice; and (f) selective evolution. We need to make our continuous efforts to link research and practice to theories, to identify specifics of our theories, to develop diverse types of theories, and to conduct international collaborative works. Our paper gives implications for future theoretical development in diverse clinical areas of nursing research and practice. © 2012 Sigma Theta Tau International.

Impact of Negative Sequence Current Injection by Wind Power Plants

DEFF Research Database (Denmark)

Chaudhary, Sanjay; Göksu, Ömer; Teodorescu, Remus

2013-01-01

This paper presents an analysis of the impact from negative sequence current injection by wind power plants in power systems under steady-state and short-term unbalanced conditions, including faults. The separate positive and negative sequence current control capability of the grid-side converters...... of full scale converter type wind turbines may be utilized to alter voltage imbalance at the point of connection and further into the grid, in turn changing the resultant negative sequence current flow in the grid. The effects of such control actions have been analyzed and discussed through theoretical...

Formation of modern theoretical regulations about organization concerning management development

Directory of Open Access Journals (Sweden)

Zhalinska I.V.

2017-03-01

Full Text Available The article deals with the scientific concepts about an organization as the entity of management concerning management development. The author studies the principal theoretical regulations about an organization within the most spread schools of management and context of development of other managerial concepts in particular, strategic management. It is found out that an organization and its development had not considered as the factor of an effective activity before. Researches paid their attention to single aspects of organization activity where the aspects allowed to increase economic efficiency. However, the objective complication of conditions of enterprises’ activities caused the necessity of scientific research of adequate models of functioning and development of organizations, which currently cannot be provided by traditional management concepts. Thus, theoretical and practical prerequisites arise for a separate scientific set of researches within the science of management such as the theory of an organization. The article describes the main classified approaches to the models of an organization. The paper researches the challenges in present management, and those ones, which have caused the crisis in modern management. It is singled out the following actual aspects of modern organizational processes as the all-round use of modern information and computer systems, the development of integration and in cooperation in management, the appearance of new management technologies, the use of new assessment criteria for organization activity, striving for organizational shifts and innovations. Due to the generalization of the study results, the authors single out such key aspects in the development of the science of management, as the crisis of traditional management influences upon practical activity of modern organizations; the achievements of traditional management schools are becoming necessary, but not determinant factors of organization

The physics and chemistry of dusty plasmas: A laboratory and theoretical investigation

Science.gov (United States)

Whipple, E. C.

1986-01-01

Theoretical work on dusty plasmas was conducted in three areas: collective effects in a dusty plasma, the role of dusty plasmas in cometary atmospheres, and the role of dusty plasmas in planetary atmospheres (particularly in the ring systems of the giant planets). Laboratory investigations consisted of studies of dust/plasma interactions and stimulated molecular excitation and infrared emission by charged dust grains. Also included is a list of current publications.

Spin currents from Helium in intense-field photo-ionization

International Nuclear Information System (INIS)

Bhattacharyya, S; Mukherjee, Mahua; Chakrabarti, J; Faisal, F H M

2007-01-01

Spin dynamics is studied by computing spin-dependent ionization current of He in intense laser field in relativistic field theoretic method. Spin-flip and spin-asymmetry in current generation is obtained with circularly polarized light. The spin-flip is a dynamical effect of intense laser field on an ionized spinning electron. Transformation properties of the up and down spin ionization amplitudes show that the sign of spin can be controlled by a change of helicity of the laser photons from outside

Theoretical studies of flash x-ray diagnostics for fuel motion experiments

International Nuclear Information System (INIS)

Halbleib, J.A. Sr.; Phillips, A.R.

1975-09-01

The results of preliminary theoretical studies concerning the possible employment of short-pulse, high-current field emission diodes as sources for the flash x-ray diagnostics of fuel-pin motion are reported. The predicted thick-target photon environments are obtained from state-of-the-art coupled electron/photon transport models. Through qualitative figures of merit these environments are used to study the importance of source current and voltage. For a selected experimental configuration a comparison is made between the absolute flash x-ray imaging signals predicted for these environments and Monte Carlo/analytic calculations of absolute fission-gamma backgrounds. These preliminary data suggest that field emission sources operating at voltages in the 1-to 5-MeV range and at currents of the order of 100-kA or greater may be adequate diagnostic sources for test-pin configurations as complex as a full LMFBR subassembly

Cathode fall model and current-voltage characteristics of field emission driven direct current microplasmas

Energy Technology Data Exchange (ETDEWEB)

Venkattraman, Ayyaswamy [Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036 (India)

2013-11-15

The post-breakdown characteristics of field emission driven microplasma are studied theoretically and numerically. A cathode fall model assuming a linearly varying electric field is used to obtain equations governing the operation of steady state field emission driven microplasmas. The results obtained from the model by solving these equations are compared with particle-in-cell with Monte Carlo collisions simulation results for parameters including the plasma potential, cathode fall thickness, ion number density in the cathode fall, and current density vs voltage curves. The model shows good overall agreement with the simulations but results in slightly overpredicted values for the plasma potential and the cathode fall thickness attributed to the assumed electric field profile. The current density vs voltage curves obtained show an arc region characterized by negative slope as well as an abnormal glow discharge characterized by a positive slope in gaps as small as 10 μm operating at atmospheric pressure. The model also retrieves the traditional macroscale current vs voltage theory in the absence of field emission.

Cathode fall model and current-voltage characteristics of field emission driven direct current microplasmas

International Nuclear Information System (INIS)

Venkattraman, Ayyaswamy

2013-01-01

The post-breakdown characteristics of field emission driven microplasma are studied theoretically and numerically. A cathode fall model assuming a linearly varying electric field is used to obtain equations governing the operation of steady state field emission driven microplasmas. The results obtained from the model by solving these equations are compared with particle-in-cell with Monte Carlo collisions simulation results for parameters including the plasma potential, cathode fall thickness, ion number density in the cathode fall, and current density vs voltage curves. The model shows good overall agreement with the simulations but results in slightly overpredicted values for the plasma potential and the cathode fall thickness attributed to the assumed electric field profile. The current density vs voltage curves obtained show an arc region characterized by negative slope as well as an abnormal glow discharge characterized by a positive slope in gaps as small as 10 μm operating at atmospheric pressure. The model also retrieves the traditional macroscale current vs voltage theory in the absence of field emission

Interface tuning of current-induced cooling in molecular circuits

Czech Academy of Sciences Publication Activity Database

Foti, Giuseppe; Vázquez, Héctor

2017-01-01

Roč. 121, č. 2 (2017), s. 1082-1088 ISSN 1932-7447 R&D Projects: GA ČR GA15-19672S Institutional support: RVO:68378271 Keywords : current-induced heating and cooling * molecular junction * Carbene Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.536, year: 2016

Reactor Core Coolability Analysis during Hypothesized Severe Accidents of OPR1000

International Nuclear Information System (INIS)

Lee, Yongjae; Seo, Seungwon; Kim, Sung Joong; Ha, Kwang Soon; Kim, Hwan-Yeol

2014-01-01

Assessment of the safety features over the hypothesized severe accidents may be performed experimentally or numerically. Due to the considerable time and expenditures, experimental assessment is implemented only to the limited cases. Therefore numerical assessment has played a major role in revisiting severe accident analysis of the existing or newly designed power plants. Computer codes for the numerical analysis of severe accidents are categorized as the fast running integral code and detailed code. Fast running integral codes are characterized by a well-balanced combination of detailed and simplified models for the simulation of the relevant phenomena within an NPP in the case of a severe accident. MAAP, MELCOR and ASTEC belong to the examples of fast running integral codes. Detailed code is to model as far as possible all relevant phenomena in detail by mechanistic models. The examples of detailed code is SCDAP/RELAP5. Using the MELCOR, Carbajo. investigated sensitivity studies of Station Black Out (SBO) using the MELCOR for Peach Bottom BWR. Park et al. conduct regulatory research of the PWR severe accident. Ahn et al. research sensitivity analysis of the severe accident for APR1400 with MELCOR 1.8.4. Lee et al. investigated RCS depressurization strategy and developed a core coolability map for independent scenarios of Small Break Loss-of-Coolant Accident (SBLOCA), SBO, and Total Loss of Feed Water (TLOFW). In this study, three initiating cases were selected, which are SBLOCA without SI, SBO, and TLOFW. The initiating cases exhibit the highest probability of transitioning into core damage according to PSA 1 of OPR 1000. The objective of this study is to investigate the reactor core coolability during hypothesized severe accidents of OPR1000. As a representative indicator, we have employed Jakob number and developed JaCET and JaMCT using the MELCOR simulation. Although the RCS pressures for the respective accident scenarios were different, the JaMCT and Ja

[The evolution of plant life span: facts and hypotheses].

Science.gov (United States)

2006-01-01

There are two different views on the evolution of life forms in Cormophyta: from woody plants to herbaceous ones or in opposite direction - from herbs to trees. In accordance with these views it is supposed that life span in plants changed in the course of evolution from many years (perennials) to few years (annuals, biennials), or went in reverse - from few years to many years. The author discusses the problems of senescence and longevity in Cormophyta in the context of various hypotheses of ageing (programmed death theory, mutation accumulation, antagonistic pleiotropy, disposable soma, genes of ageing, genes of longevity). Special attention is given to bio-morphological aspects of longevity and cases of non-ageing plants ("negative senescence", "potential immortality"). It is proposed to distinguish seven models of simple ontogenesis in Cormophyta that can exemplify the diversity of mechanisms of ageing and longevity. The evolution of life span in plants is considered as an indirect result of natural selection of other characteristics of organisms or as a consequence of fixation of modifications (episelectional evolution). It seems that short life span could emerge several times during evolution of one group of plants, thus favoring its adaptive radiation.

Investigation of the LH wave energy conversion and current drive efficiency in the HT-7 tokamak

International Nuclear Information System (INIS)

Chen, Z.Y.; Wan, B.N.; Shi, Y.J.; Lin, S.Y.; Hu, L.Q.; Asif, M.

2005-01-01

Lower hybrid current drive (LHCD) plasmas in the presence of DC electric filed have been investigated based on Karney-Fisch theory in the HT-7 tokamak. The relatively small scatter in the experimental data with various values of waveguide phasing and lower hybrid power, when plotted in the Karney-Fisch diagram, confirms that a reasonable theoretical interpretation is possible for the HT-7 data. The full non-inductively current drive efficiencies are obtained by fitting the experimental data to the theoretical curve. The efficiency strongly depends on the lower hybrid wave phase velocity

H-convergence for quasi-linear elliptic equations under natural hypotheses on the correctors

International Nuclear Information System (INIS)

Bensoussan, A.; Boccardo, L.; Dall'Aglio, A.; Murat, F.

1995-01-01

In this paper we study the behavior of the solutions of quasi-linear Dirichlet problems when the principal parts H-converge and when the lower order terms have quadratic growth with respect to the gradient. We show that the limit problem consists of a principal part which is the H-limit of the principal parts and of the lower order term which is constructed from the corresponding terms by using a linear corrector result. We assume only natural hypotheses on the correctors (i.e. L 2 equi-integrability and not L ∞ boundedness). (author)

Geophysical Evolution of Ch Asteroids and Testable Hypotheses for Future Missions

Science.gov (United States)

Castillo, J. C.

2017-12-01

The main population of asteroids related to meteorites in the collections remains to be explored in situ. Ch asteroids are the only midsized asteroids that display a signature of hydration (besides Pallas) and the spectral connection between Ch asteroids and CM chondrites suggests that the former represent potential parent bodies for the latter. This class of asteroids is particularly interesting because it hosts many objects 100-200 km in size, which are believed to belong to a primordial population of planetesimals. This presentation will explore multiple evolution pathways for Ch-asteroids leading to possible hypotheses on the geological, petrological, and geophysical properties that a disrupted parent body would present to a future mission. This work is being carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA.

Theoretical clarity is not “Manicheanism”

DEFF Research Database (Denmark)

Hjørland, Birger

2011-01-01

It is argued that in order to establish a new theoretical approach to information science it is necessary to express disagreement with some established views. The “social turn” in information science is not just exemplified in relation to the works of Marcia Bates but in relation to many different...... researchers in the field. Therefore it should not be taken personally, and the debate should focus on the substance. Marcia Bates has contributed considerably to information science. In spite of this some of her theoretical points of departure may be challenged. It is important to seek theoretical clarity...... and this may involve a degree of schematic confrontation that should not be confused with theoretical one-sidedness, “Manicheanism” or lack of respect....

Set-Theoretic Approach to Maturity Models

DEFF Research Database (Denmark)

Lasrado, Lester Allan

Despite being widely accepted and applied, maturity models in Information Systems (IS) have been criticized for the lack of theoretical grounding, methodological rigor, empirical validations, and ignorance of multiple and non-linear paths to maturity. This PhD thesis focuses on addressing...... these criticisms by incorporating recent developments in configuration theory, in particular application of set-theoretic approaches. The aim is to show the potential of employing a set-theoretic approach for maturity model research and empirically demonstrating equifinal paths to maturity. Specifically...... methodological guidelines consisting of detailed procedures to systematically apply set theoretic approaches for maturity model research and provides demonstrations of it application on three datasets. The thesis is a collection of six research papers that are written in a sequential manner. The first paper...

On Ion Cyclotron Current Drive for sawtooth control

International Nuclear Information System (INIS)

Eriksson, L.-G.; Johnson, T.; Hellsten, T.; Mayoral, M.-L.; McDonald, D.; Santala, M.; Vries, P. de; Coda, S.; Sauter, O.; Mueck, A.; Buttery, R.J.; Mantsinen, M.J.; Noterdaeme, J.-M.; Westerhof, E.

2006-01-01

Experiments using Ion Cyclotron Current Drive (ICCD) to control sawteeth are presented. In particular, discharges demonstrating shortening of fast ion induced long sawteeth reported in [L.-G. Eriksson et al., Physical Review Letters 92, 235004 (2004)] by ICCD have been analysed in detail. Numerical simulations of the ICCD driven currents are shown to be consistent with the experimental observations. They support the hypothesis that an increase of the magnetic shear, due to the driven current, at the surface where the safety factor is unity was the critical factor for the shortening of the sawteeth. In view of the potential utility of ICCD, the mechanisms for the current drive have been further investigated experimentally. This includes the influence of the averaged energy of the resonating ions carrying the current and the spectrum of the launched waves. The results of these experiments are discussed in the light of theoretical considerations. (author)

Theoretical estimation of Z´ boson mass

International Nuclear Information System (INIS)

Maji, Priya; Banerjee, Debika; Sahoo, Sukadev

2016-01-01

The discovery of Higgs boson at the LHC brings a renewed perspective in particle physics. With the help of Higgs mechanism, standard model (SM) allows the generation of particle mass. The ATLAS and CMS experiments at the LHC have predicted the mass of Higgs boson as m_H=125-126 GeV. Recently, it is claimed that the Higgs boson might interact with dark matter and there exists relation between the Higgs boson and dark matter (DM). Hertzberg has predicted a correlation between the Higgs mass and the abundance of dark matter. His theoretical result is in good agreement with current data. He has predicted the mass of Higgs boson as GeV. The Higgs boson could be coupled to the particle that constitutes all or part of the dark matter in the universe. Light Z´ boson could have important implications in dark matter phenomenology

Time evolution of the bootstrap current profile in LHD plasmas

International Nuclear Information System (INIS)

Nakamura, Yuji; Kawaoto, K.; Watanabe, K.Y.

2008-10-01

The direction of the bootstrap current is inverted in the outward shifted plasmas of the Large Helical Device (LHD). In order to verify the reliability of the theoretical models of the bootstrap current in helical plasmas, the rotational transform profiles are observed by the Motional Stark Effect measurement in the bootstrap current carrying plasmas of the LHD, and they are compared with the numerical simulations of the toroidal current profile including the bootstrap current. Since the toroidal current profile is not in the steady state in these plasmas, taking care of the inversely induced component of the toroidal current and finite duration of the resistive diffusion of the toroidal current are important in the numerical simulations. Reasonable agreement can be obtained between the rotational transform profiles measured in the experiments and those calculated in the numerical simulations. (author)

Research in theoretical elementary particle physics at the University of Florida: Task A. Annual progress report

International Nuclear Information System (INIS)

Field, R.D.; Ramond, P.M.; Sikivie, P.; Thorn, C.B.

1994-01-01

This is the Annual Progress Report of the theoretical particle theory group at the University of Florida under DOE Grant DE-FG05-86ER40272. At present our group consists of four Full Professors (Field, Ramond, Thorn, Sikivie), one Associate Professor (Woodard), and two Assistant Professors (Qiu, Kennedy). In addition, we have four postdoctoral research associates and seven graduate students. The research of our group covers a broad range of topics in theoretical high energy physics including both theory and phenomenology. Included in this report is a summary of the last several years, an outline of our current research program

Current-Induced Forces and Hot Spots in Biased Nanojunctions

DEFF Research Database (Denmark)

Lu, Jing Tao; Christensen, Rasmus Bjerregaard; Wang, Jian-Sheng

2015-01-01

We investigate theoretically the interplay of current-induced forces (CIFs), Joule heating, and heat transport inside a current-carrying nanoconductor. We find that the CIFs, due to the electron-phonon coherence, can control the spatial heat dissipation in the conductor. This yields a significant...... asymmetric concentration of excess heating (hot spot) even for a symmetric conductor. When coupled to the electrode phonons, CIFs drive different phonon heat flux into the two electrodes. First-principles calculations on realistic biased nanojunctions illustrate the importance of the effect....

ELECTRON CYCLOTRON CURRENT DRIVE EFFICIENCY IN GENERAL TOKAMAK GEOMETRY

International Nuclear Information System (INIS)

LIN-LUI, Y.R; CHAN, V.S; PRATER, R.

2003-01-01

Green's-function techniques are used to calculate electron cyclotron current drive (ECCD) efficiency in general tokamak geometry in the low-collisionality regime. Fully relativistic electron dynamics is employed in the theoretical formulation. The high-velocity collision model is used to model Coulomb collisions and a simplified quasi-linear rf diffusion operator describes wave-particle interactions. The approximate analytic solutions which are benchmarked with a widely used ECCD model, facilitate time-dependent simulations of tokamak operational scenarios using the non-inductive current drive of electron cyclotron waves

Evaluating Hypotheses of Plant Species Invasions on Mediterranean Islands: Inverse Patterns between Alien and Endemic Species

Directory of Open Access Journals (Sweden)

Alexander Bjarnason

2017-08-01

Full Text Available Invasive alien species cause major changes to ecosystem functioning and patterns of biodiversity, and the main factors involved in invasion success remain contested. Using the Mediterranean island of Crete, Greece as a case study, we suggest a framework for analyzing spatial data of alien species distributions, based on environmental predictors, aiming to gain an understanding of their spatial patterns and spread. Mediterranean islands are under strong ecological pressure from invading species due to their restricted size and increased human impact. Four hypotheses of invasibility, the “propagule pressure hypothesis” (H1, “biotic resistance hypothesis vs. acceptance hypothesis” (H2, “disturbance-mediated hypothesis” (H3, and “environmental heterogeneity hypothesis” (H4 were tested. Using data from alien, native, and endemic vascular plant species, the propagule pressure, biotic resistance vs. acceptance, disturbance-mediated, and environmental heterogeneity hypotheses were tested with Generalized Additive Modeling (GAM of 39 models. Based on model selection, the optimal model includes the positive covariates of native species richness, the negative covariates of endemic species richness, and land area. Variance partitioning between the four hypotheses indicated that the biotic resistance vs. acceptance hypothesis explained the vast majority of the total variance. These results show that areas of high species richness have greater invasibility and support the acceptance hypothesis and “rich-get-richer” distribution of alien species. The negative correlation between alien and endemic species appears to be predominantly driven by altitude, with fewer alien and more endemic species at greater altitudes, and habitat richness. The negative relationship between alien and endemic species richness provides potential for understanding patterns of endemic and alien species on islands, contributing to more effective conservation

The odderon: theoretical status and experimental tests

Energy Technology Data Exchange (ETDEWEB)

Ewerz, C. [Milano Univ., Dipt. di Fisica, and INFN (Italy); ECT, Trento (Italy)

2005-07-01

In QCD the odderon can be formed by 3 gluons in a symmetric color state. According to our understanding of high energy scattering based on the picture of gluon exchanges, the existence of the odderon is very likely. Surprisingly through, the experimental evidence for it is rather weak. Especially exclusive reactions that can be caused only by the odderon offer good chances to finally establish its existence. In perturbative QCD the odderon is under rather good control. It is already by itself a very interesting object from a theoretical point of view. It further is an important ingredient in effective theories of high energy scattering that are currently discussed. New insight into the behaviour of the non-perturbative odderon can be expected from lattice studies of glueball trajectories.

The power of theoretical knowledge.

Science.gov (United States)

Alligood, Martha Raile

2011-10-01

Nursing theoretical knowledge has demonstrated powerful contributions to education, research, administration and professional practice for guiding nursing thought and action. That knowledge has shifted the primary focus of the nurse from nursing functions to the person. Theoretical views of the person raise new questions, create new approaches and instruments for nursing research, and expand nursing scholarship throughout the world.

Theoretical and methodological foundations of the social accounting in the agricultural cooperative companies

Directory of Open Access Journals (Sweden)

Yamira Mirabal González

2013-12-01

• To value the paper of the Social Accounting in the agricultural cooperative companies.  The main results of the investigation are centered in: analysis of the peculiarities of the cooperativism in the context current Latin American and Caribbean, and in Cuba; valuation of the theoretical conceptions on Accounting, Countable Systems and Social Accounting, valuation of the paper of the Social Accounting in the agricultural cooperative companies.

Theoretical explanations for maintenance of behaviour change: a systematic review of behaviour theories

OpenAIRE

Kwasnicka, Dominika; Dombrowski, Stephan U; White, Martin; Sniehotta, Falko

2016-01-01

ABSTRACT Background: Behaviour change interventions are effective in supporting individuals in achieving temporary behaviour change. Behaviour change maintenance, however, is rarely attained. The aim of this review was to identify and synthesise current theoretical explanations for behaviour change maintenance to inform future research and practice. Methods: Potentially relevant theories were identified through systematic searches of electronic databases (Ovid MEDLINE, Embase, PsycINFO). In a...

Dynamic and energetic stabilization of persistent currents in Bose-Einstein condensates

KAUST Repository

Law, Kody; Neely, T. W.; Kevrekidis, P. G.; Anderson, B. P.; Bradley, A. S.; Carretero-Gonzá lez, R.

2014-01-01

We study conditions under which vortices in a highly oblate harmonically trapped Bose-Einstein condensate (BEC) can be stabilized due to pinning by a blue-detuned Gaussian laser beam, with particular emphasis on the potentially destabilizing effects of laser beam positioning within the BEC. Our approach involves theoretical and numerical exploration of dynamically and energetically stable pinning of vortices with winding number up to S=6, in correspondence with experimental observations. Stable pinning is quantified theoretically via Bogoliubov-de Gennes excitation spectrum computations and confirmed via direct numerical simulations for a range of conditions similar to those of experimental observations. The theoretical and numerical results indicate that the pinned winding number, or equivalently the winding number of the superfluid current about the laser beam, decays as a laser beam of fixed intensity moves away from the BEC center. Our theoretical analysis helps explain previous experimental observations and helps define limits of stable vortex pinning for future experiments involving vortex manipulation by laser beams.

Dynamic and energetic stabilization of persistent currents in Bose-Einstein condensates

KAUST Repository

Law, Kody

2014-05-09

We study conditions under which vortices in a highly oblate harmonically trapped Bose-Einstein condensate (BEC) can be stabilized due to pinning by a blue-detuned Gaussian laser beam, with particular emphasis on the potentially destabilizing effects of laser beam positioning within the BEC. Our approach involves theoretical and numerical exploration of dynamically and energetically stable pinning of vortices with winding number up to S=6, in correspondence with experimental observations. Stable pinning is quantified theoretically via Bogoliubov-de Gennes excitation spectrum computations and confirmed via direct numerical simulations for a range of conditions similar to those of experimental observations. The theoretical and numerical results indicate that the pinned winding number, or equivalently the winding number of the superfluid current about the laser beam, decays as a laser beam of fixed intensity moves away from the BEC center. Our theoretical analysis helps explain previous experimental observations and helps define limits of stable vortex pinning for future experiments involving vortex manipulation by laser beams.

Polarized parton distributions from charged-current deep-inelastic scattering

International Nuclear Information System (INIS)

Ridolfi, G

2003-01-01

We investigate the capabilities of a neutrino factory in the determination of polarized parton distributions from charged-current deep-inelastic scattering experiments, with special attention to the accuracy of this kind of measurements. We show that a neutrino factory would allow to distinguish between different theoretical scenarios for the proton spin structure

Distinguishing 'Higgs' spin hypotheses using {gamma}{gamma} and WW{sup *} decays

Energy Technology Data Exchange (ETDEWEB)

Ellis, John [King' s College London, Theoretical Particle Physics and Cosmology Group, Physics Department, London (United Kingdom); CERN, TH Division, Physics Department, Geneva (Switzerland); Fok, Ricky [York University, Department of Physics and Astronomy, Toronto, ON (Canada); Hwang, Dae Sung [Sejong University, Department of Physics, Seoul (Korea, Republic of); Sanz, Veronica [CERN, TH Division, Physics Department, Geneva (Switzerland); York University, Department of Physics and Astronomy, Toronto, ON (Canada); You, Tevong [King' s College London, Theoretical Particle Physics and Cosmology Group, Physics Department, London (United Kingdom)

2013-07-15

The new particle X recently discovered by the ATLAS and CMS Collaborations in searches for the Higgs boson has been observed to decay into {gamma}{gamma}, ZZ{sup *} and WW{sup *}, but its spin and parity, J{sup P}, remain a mystery, with J{sup P} = 0{sup +} and 2{sup +} being open possibilities. We use PYTHIA and Delphes to simulate an analysis of the angular distribution of gg {yields} X {yields} {gamma}{gamma} decays in a full 2012 data set, including realistic background levels. We show that this angular distribution should provide strong discrimination between the possibilities of spin zero and spin two with graviton-like couplings: {proportional_to}3 {sigma} if a conservative symmetric interpretation of the log-likelihood ratio (LLR) test statistic is used, and {proportional_to}6 {sigma} if a less conservative asymmetric interpretation is used. The WW and ZZ couplings of the Standard Model Higgs boson and of a 2{sup +} particle with graviton-like couplings are both expected to exhibit custodial symmetry. We simulate the present ATLAS and CMS search strategies for X {yields} WW{sup *} using PYTHIA and Delphes, and show that their efficiencies in the case of a spin-2 particle with graviton-like couplings are a factor {approx_equal} 1.9 smaller than in the spin-0 case. On the other hand, the ratio of X{sub 2{sup +}} {yields} WW{sup *} and ZZ{sup *} branching ratios is larger than that in the 0{sup +} case by a factor {approx_equal} 1.3. We find that the current ATLAS and CMS results for X {yields} WW{sup *} and X {yields} ZZ{sup *} decays are compatible with custodial symmetry under both the spin-0 and -2 hypotheses, and that the data expected to become available during 2012 are unlikely to discriminate significantly between these possibilities. (orig.)

Langmuir probe characteristic in a current - carrying magnetized plasma

International Nuclear Information System (INIS)

Stanojevic, M.; Cercek, M.; Gyergyek, T.

1995-01-01

Experimental investigation of the Langmuir probe characteristic is a magnetized plasma with an electron current along the magnetic field direction shows that the standard procedure for determination of the electron temperature and plasma density, which is applicable in a current - free magnetized plasma, gives erroneous results for these plasma parameters. However, more precise values of the plasma parameters can be calculated from the ion saturation currents and electron temperatures obtained with that procedure for two opposite orientations of the one - sided planar probe collecting surface with respect to the direction of the electron drift. With the existing theoretical models only the order of magnitude of the electron drift velocity can be accurately determined from the measured electron saturation currents for the two probe orientations. (author)

Positive deviance control-case life history: a method to develop grounded hypotheses about successful long-term avoidance of infection

Directory of Open Access Journals (Sweden)

Sandoval Milagros

2008-03-01

Full Text Available Abstract Background Prevalence rates for long-term injection drug users in some localities surpass 60% for HIV and 80% for HCV. We describe methods for developing grounded hypotheses about how some injectors avoid infection with either virus. Methods Subjects: 25 drug injectors who have injected drugs 8 – 15 years in New York City. 17 remain without antibody to either HIV or HCV; 3 are double-positives; and 5 are positive for HCV but not HIV. "Staying Safe" methodology compares serostatus groups using detailed biographical timelines and narratives; and information about how subjects maintain access to physical resources and social support; their strategies and tactics to remain safe; how they handle problems of addiction and demands by drug dealers and other drug users; and how their behaviors and strategies do or do not become socially-embedded practices. Grounded theory and life-history analysis techniques compare and contrast doubly-uninfected with those infected with both viruses or only with HCV. Results Themes and initial hypotheses emerging from analyses included two master hypotheses that, if confirmed, should help shape preventive interventions: 1 Staying uninfected is not simply a question of social structure or social position. It involves agency by drug injectors, including sustained hard work and adaptation to changing circumstances. 2 Multiple intentionalities contribute to remaining uninfected. These conscious goals include balancing one's need for drugs and one's income; developing ways to avoid drug withdrawal sickness; avoiding situations where other drug users importune you to share drugs; and avoiding HIV (and perhaps HCV infection. Thus, focusing on a single goal in prevention might be sub-optimal. Other hypotheses specify mechanisms of enacting these intentionalities. One example is finding ways to avoid extreme social ostracism. Conclusion We have identified strategies and tactics that some doubly-uninfected IDUs have

Department of Theoretical Physics - Overview

International Nuclear Information System (INIS)

Kwiecinski, J.

2000-01-01

Full text: Research activity of the Department of Theoretical Physics concerns theoretical high-energy and elementary particle physics, intermediate energy particle physics, theoretical nuclear physics, theory of nuclear matter, theory of quark-gluon plasma and of relativistic heavy-ion collisions, theoretical astrophysics and general physics. There is some emphasis on the phenomenological applications of the theoretical research, yet the more formal problems are also considered. The detailed summary of the research projects and of the results obtained in various fields is given in the abstracts. Our Department actively collaborates with other Departments of the Institute as well as with several scientific institutions both in Poland and abroad. In particular members of our Department participate in the EC network which allows mobility of researchers. Several members of our Department have also participated in the research projects funded by the Polish Committee for Scientific Research (KBN). The complete list of grants is listed separately. Besides pure research, members of our Department are also involved in graduate and undergraduate teaching activity both at our Institute as well as at other academic institutions in Cracow. At present five students are working for their Ph.D. or MSc degrees under supervision of the senior members from the Department. We continue our participation at the EC SOCRATES-ERASMUS educational programme which allows exchange of graduate students between our Department and the Department of Physics of the University of Durham in the UK. (author)

Non-superconducting persistent currents. Des courants permanents mais pas supraconducteurs

Energy Technology Data Exchange (ETDEWEB)

Benoit, A; Mailly, D

1993-03-01

Forecasted ten years ago a quantum effect is evidenced: persistent currents in small non-superconducting loops in a magnetic field at low temperature. The loop (diameter 2.5 micrometer) is etched in a semiconducting structure GaAs/GaAlAs, where the coherence length is 25 [mu]m, the current is measured with a squid on the same chip, a value of 4 nano amps is found which agrees well with the theoretical value of 5 nA.

Theoretical Mathematics

Science.gov (United States)

Stöltzner, Michael

Answering to the double-faced influence of string theory on mathematical practice and rigour, the mathematical physicists Arthur Jaffe and Frank Quinn have contemplated the idea that there exists a `theoretical' mathematics (alongside `theoretical' physics) whose basic structures and results still require independent corroboration by mathematical proof. In this paper, I shall take the Jaffe-Quinn debate mainly as a problem of mathematical ontology and analyse it against the backdrop of two philosophical views that are appreciative towards informal mathematical development and conjectural results: Lakatos's methodology of proofs and refutations and John von Neumann's opportunistic reading of Hilbert's axiomatic method. The comparison of both approaches shows that mitigating Lakatos's falsificationism makes his insights about mathematical quasi-ontology more relevant to 20th century mathematics in which new structures are introduced by axiomatisation and not necessarily motivated by informal ancestors. The final section discusses the consequences of string theorists' claim to finality for the theory's mathematical make-up. I argue that ontological reductionism as advocated by particle physicists and the quest for mathematically deeper axioms do not necessarily lead to identical results.